NEWS
author wenzelm
Tue Jul 21 01:05:10 2009 +0200 (2009-07-21)
changeset 32092 6a5995438266
parent 32079 5dc52b199815
child 32131 7913823f14e3
permissions -rw-r--r--
Display.pretty_thm now requires a proper context;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Discontinued old form of "escaped symbols" such as \\<forall>.  Only
    10 one backslash should be used, even in ML sources.
    11 
    12 
    13 *** Pure ***
    14 
    15 * On instantiation of classes, remaining undefined class parameters
    16 are formally declared.  INCOMPATIBILITY.
    17 
    18 
    19 *** HOL ***
    20 
    21 * Code generator attributes follow the usual underscore convention:
    22     code_unfold     replaces    code unfold
    23     code_post       replaces    code post
    24     etc.
    25   INCOMPATIBILITY.
    26 
    27 * New quickcheck implementation using new code generator.
    28 
    29 * New type class boolean_algebra.
    30 
    31 * Refinements to lattices classes:
    32   - added boolean_algebra type class
    33   - less default intro/elim rules in locale variant, more default
    34     intro/elim rules in class variant: more uniformity
    35   - lemma ge_sup_conv renamed to le_sup_iff, in accordance with le_inf_iff
    36   - dropped lemma alias inf_ACI for inf_aci (same for sup_ACI and sup_aci)
    37   - renamed ACI to inf_sup_aci
    38 
    39 * Class semiring_div requires superclass no_zero_divisors and proof of
    40 div_mult_mult1; theorems div_mult_mult1, div_mult_mult2,
    41 div_mult_mult1_if, div_mult_mult1 and div_mult_mult2 have been
    42 generalized to class semiring_div, subsuming former theorems
    43 zdiv_zmult_zmult1, zdiv_zmult_zmult1_if, zdiv_zmult_zmult1 and
    44 zdiv_zmult_zmult2.  div_mult_mult1 is now [simp] by default.
    45 INCOMPATIBILITY.
    46 
    47 * Power operations on relations and functions are now one dedicate
    48 constant compow with infix syntax "^^".  Power operations on
    49 multiplicative monoids retains syntax "^" and is now defined generic
    50 in class power.  INCOMPATIBILITY.
    51 
    52 * ML antiquotation @{code_datatype} inserts definition of a datatype
    53 generated by the code generator; see Predicate.thy for an example.
    54 
    55 * New method "linarith" invokes existing linear arithmetic decision
    56 procedure only.
    57 
    58 * Implementation of quickcheck using generic code generator; default
    59 generators are provided for all suitable HOL types, records and
    60 datatypes.
    61 
    62 * Constants Set.Pow and Set.image now with authentic syntax;
    63 object-logic definitions Set.Pow_def and Set.image_def.
    64 INCOMPATIBILITY.
    65 
    66 * Renamed theorems:
    67 Suc_eq_add_numeral_1 -> Suc_eq_plus1
    68 Suc_eq_add_numeral_1_left -> Suc_eq_plus1_left
    69 Suc_plus1 -> Suc_eq_plus1
    70 
    71 * New sledgehammer option "Full Types" in Proof General settings menu.
    72 Causes full type information to be output to the ATPs.  This slows
    73 ATPs down considerably but eliminates a source of unsound "proofs"
    74 that fail later.
    75 
    76 * Discontinued ancient tradition to suffix certain ML module names
    77 with "_package", e.g.:
    78 
    79     DatatypePackage ~> Datatype
    80     InductivePackage ~> Inductive
    81 
    82     etc.
    83 
    84 INCOMPATIBILITY.
    85 
    86 * NewNumberTheory: Jeremy Avigad's new version of part of
    87 NumberTheory.  If possible, use NewNumberTheory, not NumberTheory.
    88 
    89 * Simplified interfaces of datatype module.  INCOMPATIBILITY.
    90 
    91 * Abbreviation "arbitrary" of "undefined" has disappeared; use
    92 "undefined" directly.  INCOMPATIBILITY.
    93 
    94 * New evaluator "approximate" approximates an real valued term using
    95 the same method as the approximation method.
    96 
    97 * Method "approximate" supports now arithmetic expressions as
    98 boundaries of intervals and implements interval splitting and Taylor
    99 series expansion.
   100 
   101 * Changed DERIV_intros to a dynamic fact (via Named_Thms).  Each of
   102 the theorems in DERIV_intros assumes composition with an additional
   103 function and matches a variable to the derivative, which has to be
   104 solved by the simplifier.  Hence (auto intro!: DERIV_intros) computes
   105 the derivative of most elementary terms.
   106 
   107 * Maclauren.DERIV_tac and Maclauren.deriv_tac was removed, they are
   108 replaced by: (auto intro!: DERIV_intros).  INCOMPATIBILITY.
   109 
   110 
   111 *** ML ***
   112 
   113 * Renamed functor TableFun to Table, and GraphFun to Graph.  (Since
   114 functors have their own ML name space there is no point to mark them
   115 separately.)  Minor INCOMPATIBILITY.
   116 
   117 * Renamed NamedThmsFun to Named_Thms.  INCOMPATIBILITY.
   118 
   119 * Eliminated old Attrib.add_attributes, Method.add_methods and related
   120 cominators for "args".  INCOMPATIBILITY, need to use simplified
   121 Attrib/Method.setup introduced in Isabelle2009.
   122 
   123 * Display.pretty_thm now requires a proper context (cf. former
   124 ProofContext.pretty_thm).  May fall back on Display.pretty_thm_global
   125 or even Display.pretty_thm_without_context as last resort.
   126 INCOMPATIBILITY.
   127 
   128 
   129 *** System ***
   130 
   131 * Discontinued support for Poly/ML 4.x versions.
   132 
   133 * Removed "compress" option from isabelle-process and isabelle usedir;
   134 this is always enabled.
   135 
   136 * More fine-grained control of proof parallelism, cf.
   137 Goal.parallel_proofs in ML and usedir option -q LEVEL.
   138 
   139 
   140 
   141 New in Isabelle2009 (April 2009)
   142 --------------------------------
   143 
   144 *** General ***
   145 
   146 * Simplified main Isabelle executables, with less surprises on
   147 case-insensitive file-systems (such as Mac OS).
   148 
   149   - The main Isabelle tool wrapper is now called "isabelle" instead of
   150     "isatool."
   151 
   152   - The former "isabelle" alias for "isabelle-process" has been
   153     removed (should rarely occur to regular users).
   154 
   155   - The former "isabelle-interface" and its alias "Isabelle" have been
   156     removed (interfaces are now regular Isabelle tools).
   157 
   158 Within scripts and make files, the Isabelle environment variables
   159 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
   160 respectively.  (The latter are still available as legacy feature.)
   161 
   162 The old isabelle-interface wrapper could react in confusing ways if
   163 the interface was uninstalled or changed otherwise.  Individual
   164 interface tool configuration is now more explicit, see also the
   165 Isabelle system manual.  In particular, Proof General is now available
   166 via "isabelle emacs".
   167 
   168 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
   169 purge installed copies of Isabelle executables and re-run "isabelle
   170 install -p ...", or use symlinks.
   171 
   172 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
   173 old ~/isabelle, which was slightly non-standard and apt to cause
   174 surprises on case-insensitive file-systems (such as Mac OS).
   175 
   176 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
   177 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
   178 care is required when using older releases of Isabelle.  Note that
   179 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
   180 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
   181 
   182 * Proofs of fully specified statements are run in parallel on
   183 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
   184 a regular 4-core machine, if the initial heap space is made reasonably
   185 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
   186 
   187 * The main reference manuals ("isar-ref", "implementation", and
   188 "system") have been updated and extended.  Formally checked references
   189 as hyperlinks are now available uniformly.
   190 
   191 
   192 *** Pure ***
   193 
   194 * Complete re-implementation of locales.  INCOMPATIBILITY in several
   195 respects.  The most important changes are listed below.  See the
   196 Tutorial on Locales ("locales" manual) for details.
   197 
   198 - In locale expressions, instantiation replaces renaming.  Parameters
   199 must be declared in a for clause.  To aid compatibility with previous
   200 parameter inheritance, in locale declarations, parameters that are not
   201 'touched' (instantiation position "_" or omitted) are implicitly added
   202 with their syntax at the beginning of the for clause.
   203 
   204 - Syntax from abbreviations and definitions in locales is available in
   205 locale expressions and context elements.  The latter is particularly
   206 useful in locale declarations.
   207 
   208 - More flexible mechanisms to qualify names generated by locale
   209 expressions.  Qualifiers (prefixes) may be specified in locale
   210 expressions, and can be marked as mandatory (syntax: "name!:") or
   211 optional (syntax "name?:").  The default depends for plain "name:"
   212 depends on the situation where a locale expression is used: in
   213 commands 'locale' and 'sublocale' prefixes are optional, in
   214 'interpretation' and 'interpret' prefixes are mandatory.  The old
   215 implicit qualifiers derived from the parameter names of a locale are
   216 no longer generated.
   217 
   218 - Command "sublocale l < e" replaces "interpretation l < e".  The
   219 instantiation clause in "interpretation" and "interpret" (square
   220 brackets) is no longer available.  Use locale expressions.
   221 
   222 - When converting proof scripts, mandatory qualifiers in
   223 'interpretation' and 'interpret' should be retained by default, even
   224 if this is an INCOMPATIBILITY compared to former behavior.  In the
   225 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   226 in locale expressions range over a single locale instance only.
   227 
   228 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   229 In existing theorem specifications replace the includes element by the
   230 respective context elements of the included locale, omitting those
   231 that are already present in the theorem specification.  Multiple
   232 assume elements of a locale should be replaced by a single one
   233 involving the locale predicate.  In the proof body, declarations (most
   234 notably theorems) may be regained by interpreting the respective
   235 locales in the proof context as required (command "interpret").
   236 
   237 If using "includes" in replacement of a target solely because the
   238 parameter types in the theorem are not as general as in the target,
   239 consider declaring a new locale with additional type constraints on
   240 the parameters (context element "constrains").
   241 
   242 - Discontinued "locale (open)".  INCOMPATIBILITY.
   243 
   244 - Locale interpretation commands no longer attempt to simplify goal.
   245 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   246 methods intro_locales and unfold_locales to clarify.
   247 
   248 - Locale interpretation commands no longer accept interpretation
   249 attributes.  INCOMPATIBILITY.
   250 
   251 * Class declaration: so-called "base sort" must not be given in import
   252 list any longer, but is inferred from the specification.  Particularly
   253 in HOL, write
   254 
   255     class foo = ...
   256 
   257 instead of
   258 
   259     class foo = type + ...
   260 
   261 * Class target: global versions of theorems stemming do not carry a
   262 parameter prefix any longer.  INCOMPATIBILITY.
   263 
   264 * Class 'instance' command no longer accepts attached definitions.
   265 INCOMPATIBILITY, use proper 'instantiation' target instead.
   266 
   267 * Recovered hiding of consts, which was accidentally broken in
   268 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   269 makes c inaccessible; consider using ``hide (open) const c'' instead.
   270 
   271 * Slightly more coherent Pure syntax, with updated documentation in
   272 isar-ref manual.  Removed locales meta_term_syntax and
   273 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   274 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   275 directly in regular applications.
   276 
   277 * There is a new syntactic category "float_const" for signed decimal
   278 fractions (e.g. 123.45 or -123.45).
   279 
   280 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   281 interface with 'setup' command instead.
   282 
   283 * Command 'local_setup' is similar to 'setup', but operates on a local
   284 theory context.
   285 
   286 * The 'axiomatization' command now only works within a global theory
   287 context.  INCOMPATIBILITY.
   288 
   289 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   290 hypotheses.  Sorts required in the course of reasoning need to be
   291 covered by the constraints in the initial statement, completed by the
   292 type instance information of the background theory.  Non-trivial sort
   293 hypotheses, which rarely occur in practice, may be specified via
   294 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   295 
   296   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   297 
   298 The result contains an implicit sort hypotheses as before --
   299 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   300 normalization.
   301 
   302 * Generalized Isar history, with support for linear undo, direct state
   303 addressing etc.
   304 
   305 * Changed defaults for unify configuration options:
   306 
   307   unify_trace_bound = 50 (formerly 25)
   308   unify_search_bound = 60 (formerly 30)
   309 
   310 * Different bookkeeping for code equations (INCOMPATIBILITY):
   311 
   312   a) On theory merge, the last set of code equations for a particular
   313      constant is taken (in accordance with the policy applied by other
   314      parts of the code generator framework).
   315 
   316   b) Code equations stemming from explicit declarations (e.g. code
   317      attribute) gain priority over default code equations stemming
   318      from definition, primrec, fun etc.
   319 
   320 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   321 
   322 * Unified theorem tables for both code generators.  Thus [code
   323 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   324 
   325 * Command 'find_consts' searches for constants based on type and name
   326 patterns, e.g.
   327 
   328     find_consts "_ => bool"
   329 
   330 By default, matching is against subtypes, but it may be restricted to
   331 the whole type.  Searching by name is possible.  Multiple queries are
   332 conjunctive and queries may be negated by prefixing them with a
   333 hyphen:
   334 
   335     find_consts strict: "_ => bool" name: "Int" -"int => int"
   336 
   337 * New 'find_theorems' criterion "solves" matches theorems that
   338 directly solve the current goal (modulo higher-order unification).
   339 
   340 * Auto solve feature for main theorem statements: whenever a new goal
   341 is stated, "find_theorems solves" is called; any theorems that could
   342 solve the lemma directly are listed as part of the goal state.
   343 Cf. associated options in Proof General Isabelle settings menu,
   344 enabled by default, with reasonable timeout for pathological cases of
   345 higher-order unification.
   346 
   347 
   348 *** Document preparation ***
   349 
   350 * Antiquotation @{lemma} now imitates a regular terminal proof,
   351 demanding keyword 'by' and supporting the full method expression
   352 syntax just like the Isar command 'by'.
   353 
   354 
   355 *** HOL ***
   356 
   357 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   358 points Main and Complex_Main remain as before.
   359 
   360 * Logic image HOL-Plain provides a minimal HOL with the most important
   361 tools available (inductive, datatype, primrec, ...).  This facilitates
   362 experimentation and tool development.  Note that user applications
   363 (and library theories) should never refer to anything below theory
   364 Main, as before.
   365 
   366 * Logic image HOL-Main stops at theory Main, and thus facilitates
   367 experimentation due to shorter build times.
   368 
   369 * Logic image HOL-NSA contains theories of nonstandard analysis which
   370 were previously part of former HOL-Complex.  Entry point Hyperreal
   371 remains valid, but theories formerly using Complex_Main should now use
   372 new entry point Hypercomplex.
   373 
   374 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   375 Posix processes.  Avoids potentially expensive forking of the ML
   376 process.  New thread-based implementation also works on non-Unix
   377 platforms (Cygwin).  Provers are no longer hardwired, but defined
   378 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   379 commands are covered in the isar-ref manual.
   380 
   381 * Wrapper scripts for remote SystemOnTPTP service allows to use
   382 sledgehammer without local ATP installation (Vampire etc.). Other
   383 provers may be included via suitable ML wrappers, see also
   384 src/HOL/ATP_Linkup.thy.
   385 
   386 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   387 menu.
   388 
   389 * The metis method no longer fails because the theorem is too trivial
   390 (contains the empty clause).
   391 
   392 * The metis method now fails in the usual manner, rather than raising
   393 an exception, if it determines that it cannot prove the theorem.
   394 
   395 * Method "coherent" implements a prover for coherent logic (see also
   396 src/Tools/coherent.ML).
   397 
   398 * Constants "undefined" and "default" replace "arbitrary".  Usually
   399 "undefined" is the right choice to replace "arbitrary", though
   400 logically there is no difference.  INCOMPATIBILITY.
   401 
   402 * Command "value" now integrates different evaluation mechanisms.  The
   403 result of the first successful evaluation mechanism is printed.  In
   404 square brackets a particular named evaluation mechanisms may be
   405 specified (currently, [SML], [code] or [nbe]).  See further
   406 src/HOL/ex/Eval_Examples.thy.
   407 
   408 * Normalization by evaluation now allows non-leftlinear equations.
   409 Declare with attribute [code nbe].
   410 
   411 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   412 as the structured Isar versions "cases" and "induct", cf. the
   413 corresponding "cases" and "induct" attributes.  Mutual induction rules
   414 are now presented as a list of individual projections
   415 (e.g. foo_bar.inducts for types foo and bar); the old format with
   416 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   417 rare situations a different rule is selected --- notably nested tuple
   418 elimination instead of former prod.exhaust: use explicit (case_tac t
   419 rule: prod.exhaust) here.
   420 
   421 * Attributes "cases", "induct", "coinduct" support "del" option.
   422 
   423 * Removed fact "case_split_thm", which duplicates "case_split".
   424 
   425 * The option datatype has been moved to a new theory Option.  Renamed
   426 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   427 
   428 * New predicate "strict_mono" classifies strict functions on partial
   429 orders.  With strict functions on linear orders, reasoning about
   430 (in)equalities is facilitated by theorems "strict_mono_eq",
   431 "strict_mono_less_eq" and "strict_mono_less".
   432 
   433 * Some set operations are now proper qualified constants with
   434 authentic syntax.  INCOMPATIBILITY:
   435 
   436     op Int ~>   Set.Int
   437     op Un ~>    Set.Un
   438     INTER ~>    Set.INTER
   439     UNION ~>    Set.UNION
   440     Inter ~>    Set.Inter
   441     Union ~>    Set.Union
   442     {} ~>       Set.empty
   443     UNIV ~>     Set.UNIV
   444 
   445 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   446 theory Set.
   447 
   448 * Auxiliary class "itself" has disappeared -- classes without any
   449 parameter are treated as expected by the 'class' command.
   450 
   451 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   452 
   453 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   454 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   455 
   456 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   457 method "approximation".  It proves formulas on real values by using
   458 interval arithmetic.  In the formulas are also the transcendental
   459 functions sin, cos, tan, atan, ln, exp and the constant pi are
   460 allowed. For examples see
   461 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   462 
   463 * Theory "Reflection" now resides in HOL/Library.
   464 
   465 * Entry point to Word library now simply named "Word".
   466 INCOMPATIBILITY.
   467 
   468 * Made source layout more coherent with logical distribution
   469 structure:
   470 
   471     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   472     src/HOL/Library/Code_Message.thy ~> src/HOL/
   473     src/HOL/Library/GCD.thy ~> src/HOL/
   474     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   475     src/HOL/Library/Parity.thy ~> src/HOL/
   476     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   477     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   478     src/HOL/Real/Lubs.thy ~> src/HOL/
   479     src/HOL/Real/PReal.thy ~> src/HOL/
   480     src/HOL/Real/Rational.thy ~> src/HOL/
   481     src/HOL/Real/RComplete.thy ~> src/HOL/
   482     src/HOL/Real/RealDef.thy ~> src/HOL/
   483     src/HOL/Real/RealPow.thy ~> src/HOL/
   484     src/HOL/Real/Real.thy ~> src/HOL/
   485     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   486     src/HOL/Complex/Complex.thy ~> src/HOL/
   487     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   488     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   489     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   490     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   491     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   492     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   493     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   494     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   495     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   496     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   497     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   498     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   499     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   500     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   501     src/HOL/Real/Float ~> src/HOL/Library/
   502     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   503     src/HOL/Real/RealVector.thy ~> src/HOL/
   504 
   505     src/HOL/arith_data.ML ~> src/HOL/Tools
   506     src/HOL/hologic.ML ~> src/HOL/Tools
   507     src/HOL/simpdata.ML ~> src/HOL/Tools
   508     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   509     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   510     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   511     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   512     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   513     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   514     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   515 
   516     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   517     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   518     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   519     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   520     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   521     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   522 
   523 * If methods "eval" and "evaluation" encounter a structured proof
   524 state with !!/==>, only the conclusion is evaluated to True (if
   525 possible), avoiding strange error messages.
   526 
   527 * Method "sizechange" automates termination proofs using (a
   528 modification of) the size-change principle.  Requires SAT solver.  See
   529 src/HOL/ex/Termination.thy for examples.
   530 
   531 * Simplifier: simproc for let expressions now unfolds if bound
   532 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   533 
   534 * Method "arith": Linear arithmetic now ignores all inequalities when
   535 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   536 
   537 * New attribute "arith" for facts that should always be used
   538 automatically by arithmetic. It is intended to be used locally in
   539 proofs, e.g.
   540 
   541   assumes [arith]: "x > 0"
   542 
   543 Global usage is discouraged because of possible performance impact.
   544 
   545 * New classes "top" and "bot" with corresponding operations "top" and
   546 "bot" in theory Orderings; instantiation of class "complete_lattice"
   547 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   548 
   549 * Changed definition lemma "less_fun_def" in order to provide an
   550 instance for preorders on functions; use lemma "less_le" instead.
   551 INCOMPATIBILITY.
   552 
   553 * Theory Orderings: class "wellorder" moved here, with explicit
   554 induction rule "less_induct" as assumption.  For instantiation of
   555 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   556 INCOMPATIBILITY.
   557 
   558 * Theory Orderings: added class "preorder" as superclass of "order".
   559 INCOMPATIBILITY: Instantiation proofs for order, linorder
   560 etc. slightly changed.  Some theorems named order_class.* now named
   561 preorder_class.*.
   562 
   563 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   564 "diag" to "Id_on".
   565 
   566 * Theory Finite_Set: added a new fold combinator of type
   567 
   568   ('a => 'b => 'b) => 'b => 'a set => 'b
   569 
   570 Occasionally this is more convenient than the old fold combinator
   571 which is now defined in terms of the new one and renamed to
   572 fold_image.
   573 
   574 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   575 and "ring_simps" have been replaced by "algebra_simps" (which can be
   576 extended with further lemmas!).  At the moment both still exist but
   577 the former will disappear at some point.
   578 
   579 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   580 class recpower.  Type-specific simp rules for various recpower types
   581 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   582 
   583 rat_power_0    -> power_0
   584 rat_power_Suc  -> power_Suc
   585 realpow_0      -> power_0
   586 realpow_Suc    -> power_Suc
   587 complexpow_0   -> power_0
   588 complexpow_Suc -> power_Suc
   589 power_poly_0   -> power_0
   590 power_poly_Suc -> power_Suc
   591 
   592 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   593 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   594 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   595 of lemmas from Divides has been generalized from nat to class
   596 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   597 renames resulting from duplicate elimination:
   598 
   599     dvd_def_mod ~>          dvd_eq_mod_eq_0
   600     zero_dvd_iff ~>         dvd_0_left_iff
   601     dvd_0 ~>                dvd_0_right
   602     DIVISION_BY_ZERO_DIV ~> div_by_0
   603     DIVISION_BY_ZERO_MOD ~> mod_by_0
   604     mult_div ~>             div_mult_self2_is_id
   605     mult_mod ~>             mod_mult_self2_is_0
   606 
   607 * Theory IntDiv: removed many lemmas that are instances of class-based
   608 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   609 rename old lemmas as follows:
   610 
   611 dvd_diff               -> nat_dvd_diff
   612 dvd_zminus_iff         -> dvd_minus_iff
   613 mod_add1_eq            -> mod_add_eq
   614 mod_mult1_eq           -> mod_mult_right_eq
   615 mod_mult1_eq'          -> mod_mult_left_eq
   616 mod_mult_distrib_mod   -> mod_mult_eq
   617 nat_mod_add_left_eq    -> mod_add_left_eq
   618 nat_mod_add_right_eq   -> mod_add_right_eq
   619 nat_mod_div_trivial    -> mod_div_trivial
   620 nat_mod_mod_trivial    -> mod_mod_trivial
   621 zdiv_zadd_self1        -> div_add_self1
   622 zdiv_zadd_self2        -> div_add_self2
   623 zdiv_zmult_self1       -> div_mult_self2_is_id
   624 zdiv_zmult_self2       -> div_mult_self1_is_id
   625 zdvd_triv_left         -> dvd_triv_left
   626 zdvd_triv_right        -> dvd_triv_right
   627 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   628 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   629 zmod_zadd_left_eq      -> mod_add_left_eq
   630 zmod_zadd_right_eq     -> mod_add_right_eq
   631 zmod_zadd_self1        -> mod_add_self1
   632 zmod_zadd_self2        -> mod_add_self2
   633 zmod_zadd1_eq          -> mod_add_eq
   634 zmod_zdiff1_eq         -> mod_diff_eq
   635 zmod_zdvd_zmod         -> mod_mod_cancel
   636 zmod_zmod_cancel       -> mod_mod_cancel
   637 zmod_zmult_self1       -> mod_mult_self2_is_0
   638 zmod_zmult_self2       -> mod_mult_self1_is_0
   639 zmod_1                 -> mod_by_1
   640 zdiv_1                 -> div_by_1
   641 zdvd_abs1              -> abs_dvd_iff
   642 zdvd_abs2              -> dvd_abs_iff
   643 zdvd_refl              -> dvd_refl
   644 zdvd_trans             -> dvd_trans
   645 zdvd_zadd              -> dvd_add
   646 zdvd_zdiff             -> dvd_diff
   647 zdvd_zminus_iff        -> dvd_minus_iff
   648 zdvd_zminus2_iff       -> minus_dvd_iff
   649 zdvd_zmultD            -> dvd_mult_right
   650 zdvd_zmultD2           -> dvd_mult_left
   651 zdvd_zmult_mono        -> mult_dvd_mono
   652 zdvd_0_right           -> dvd_0_right
   653 zdvd_0_left            -> dvd_0_left_iff
   654 zdvd_1_left            -> one_dvd
   655 zminus_dvd_iff         -> minus_dvd_iff
   656 
   657 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   658 
   659 * The real numbers offer decimal input syntax: 12.34 is translated
   660 into 1234/10^2. This translation is not reversed upon output.
   661 
   662 * Theory Library/Polynomial defines an abstract type 'a poly of
   663 univariate polynomials with coefficients of type 'a.  In addition to
   664 the standard ring operations, it also supports div and mod.  Code
   665 generation is also supported, using list-style constructors.
   666 
   667 * Theory Library/Inner_Product defines a class of real_inner for real
   668 inner product spaces, with an overloaded operation inner :: 'a => 'a
   669 => real.  Class real_inner is a subclass of real_normed_vector from
   670 theory RealVector.
   671 
   672 * Theory Library/Product_Vector provides instances for the product
   673 type 'a * 'b of several classes from RealVector and Inner_Product.
   674 Definitions of addition, subtraction, scalar multiplication, norms,
   675 and inner products are included.
   676 
   677 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   678 addition to the field operations, numerals and case syntax are also
   679 supported.
   680 
   681 * Theory Library/Diagonalize provides constructive version of Cantor's
   682 first diagonalization argument.
   683 
   684 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   685 zlcm (for int); carried together from various gcd/lcm developements in
   686 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   687 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   688 may recover tupled syntax as follows:
   689 
   690     hide (open) const gcd
   691     abbreviation gcd where
   692       "gcd == (%(a, b). GCD.gcd a b)"
   693     notation (output)
   694       GCD.gcd ("gcd '(_, _')")
   695 
   696 The same works for lcm, zgcd, zlcm.
   697 
   698 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   699 instantiations for algebraic structures.  Removed some duplicate
   700 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   701 
   702 * ML antiquotation @{code} takes a constant as argument and generates
   703 corresponding code in background and inserts name of the corresponding
   704 resulting ML value/function/datatype constructor binding in place.
   705 All occurrences of @{code} with a single ML block are generated
   706 simultaneously.  Provides a generic and safe interface for
   707 instrumentalizing code generation.  See
   708 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   709 In future you ought to refrain from ad-hoc compiling generated SML
   710 code on the ML toplevel.  Note that (for technical reasons) @{code}
   711 cannot refer to constants for which user-defined serializations are
   712 set.  Refer to the corresponding ML counterpart directly in that
   713 cases.
   714 
   715 * Command 'rep_datatype': instead of theorem names the command now
   716 takes a list of terms denoting the constructors of the type to be
   717 represented as datatype.  The characteristic theorems have to be
   718 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   719 have disappeared in favour of existing ones:
   720 
   721     unit_induct                 ~> unit.induct
   722     prod_induct                 ~> prod.induct
   723     sum_induct                  ~> sum.induct
   724     Suc_Suc_eq                  ~> nat.inject
   725     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   726 
   727 
   728 *** HOL-Algebra ***
   729 
   730 * New locales for orders and lattices where the equivalence relation
   731 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   732 locales use a record structure with field eq for the equivalence.
   733 
   734 * New theory of factorial domains.
   735 
   736 * Units_l_inv and Units_r_inv are now simp rules by default.
   737 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   738 and/or r_inv will now also require deletion of these lemmas.
   739 
   740 * Renamed the following theorems, INCOMPATIBILITY:
   741 
   742 UpperD ~> Upper_memD
   743 LowerD ~> Lower_memD
   744 least_carrier ~> least_closed
   745 greatest_carrier ~> greatest_closed
   746 greatest_Lower_above ~> greatest_Lower_below
   747 one_zero ~> carrier_one_zero
   748 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   749 
   750 
   751 *** HOL-Nominal ***
   752 
   753 * Nominal datatypes can now contain type-variables.
   754 
   755 * Commands 'nominal_inductive' and 'equivariance' work with local
   756 theory targets.
   757 
   758 * Nominal primrec can now works with local theory targets and its
   759 specification syntax now conforms to the general format as seen in
   760 'inductive' etc.
   761 
   762 * Method "perm_simp" honours the standard simplifier attributes
   763 (no_asm), (no_asm_use) etc.
   764 
   765 * The new predicate #* is defined like freshness, except that on the
   766 left hand side can be a set or list of atoms.
   767 
   768 * Experimental command 'nominal_inductive2' derives strong induction
   769 principles for inductive definitions.  In contrast to
   770 'nominal_inductive', which can only deal with a fixed number of
   771 binders, it can deal with arbitrary expressions standing for sets of
   772 atoms to be avoided.  The only inductive definition we have at the
   773 moment that needs this generalisation is the typing rule for Lets in
   774 the algorithm W:
   775 
   776  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   777  -----------------------------------------------------------------
   778          Gamma |- Let x be t1 in t2 : T2
   779 
   780 In this rule one wants to avoid all the binders that are introduced by
   781 "close Gamma T1".  We are looking for other examples where this
   782 feature might be useful.  Please let us know.
   783 
   784 
   785 *** HOLCF ***
   786 
   787 * Reimplemented the simplification procedure for proving continuity
   788 subgoals.  The new simproc is extensible; users can declare additional
   789 continuity introduction rules with the attribute [cont2cont].
   790 
   791 * The continuity simproc now uses a different introduction rule for
   792 solving continuity subgoals on terms with lambda abstractions.  In
   793 some rare cases the new simproc may fail to solve subgoals that the
   794 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   795 Potential INCOMPATIBILITY.
   796 
   797 * Command 'fixrec': specification syntax now conforms to the general
   798 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   799 examples.  INCOMPATIBILITY.
   800 
   801 
   802 *** ZF ***
   803 
   804 * Proof of Zorn's Lemma for partial orders.
   805 
   806 
   807 *** ML ***
   808 
   809 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   810 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   811 depends on multithreading, so timouts will not work before Poly/ML
   812 5.2.1!
   813 
   814 * High-level support for concurrent ML programming, see
   815 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   816 particularly convenient to organize independent functional
   817 computations.  The concept of "synchronized variables" provides a
   818 higher-order interface for components with shared state, avoiding the
   819 delicate details of mutexes and condition variables.  (Requires
   820 Poly/ML 5.2.1 or later.)
   821 
   822 * ML bindings produced via Isar commands are stored within the Isar
   823 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   824 become thread-safe and work with undo as expected (concerning
   825 top-level bindings, not side-effects on global references).
   826 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   827 compiler at runtime; really global bindings need to be given outside a
   828 theory.  (Requires Poly/ML 5.2 or later.)
   829 
   830 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   831 context.  Top-level ML bindings are stored within the proof context in
   832 a purely sequential fashion, disregarding the nested proof structure.
   833 ML bindings introduced by 'ML_prf' are discarded at the end of the
   834 proof.  (Requires Poly/ML 5.2 or later.)
   835 
   836 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   837 and Method.setup, as well as Isar commands 'attribute_setup' and
   838 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   839 existing code accordingly, or use plain 'setup' together with old
   840 Method.add_method.
   841 
   842 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   843 to 'a -> thm, while results are always tagged with an authentic oracle
   844 name.  The Isar command 'oracle' is now polymorphic, no argument type
   845 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   846 accordingly.  Note that extra performance may be gained by producing
   847 the cterm carefully, avoiding slow Thm.cterm_of.
   848 
   849 * Simplified interface for defining document antiquotations via
   850 ThyOutput.antiquotation, ThyOutput.output, and optionally
   851 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   852 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   853 examples.
   854 
   855 * More systematic treatment of long names, abstract name bindings, and
   856 name space operations.  Basic operations on qualified names have been
   857 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   858 Long_Name.append.  Old type bstring has been mostly replaced by
   859 abstract type binding (see structure Binding), which supports precise
   860 qualification by packages and local theory targets, as well as proper
   861 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   862 bstring values into Binding.name, or better pass through abstract
   863 bindings everywhere.  See further src/Pure/General/long_name.ML,
   864 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   865 
   866 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   867 LocalTheory.note etc.) now refer to the *full* internal name, not the
   868 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   869 
   870 * Disposed old type and term read functions (Sign.read_def_typ,
   871 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   872 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   873 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   874 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   875 resort for legacy applications.
   876 
   877 * Disposed old declarations, tactics, tactic combinators that refer to
   878 the simpset or claset of an implicit theory (such as Addsimps,
   879 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   880 embedded ML text, or local_simpset_of with a proper context passed as
   881 explicit runtime argument.
   882 
   883 * Rules and tactics that read instantiations (read_instantiate,
   884 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   885 context, which is required for parsing and type-checking.  Moreover,
   886 the variables are specified as plain indexnames, not string encodings
   887 thereof.  INCOMPATIBILITY.
   888 
   889 * Generic Toplevel.add_hook interface allows to analyze the result of
   890 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   891 for theorem dependency output of transactions resulting in a new
   892 theory state.
   893 
   894 * ML antiquotations: block-structured compilation context indicated by
   895 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   896 
   897   @{binding name}                         - basic name binding
   898   @{let ?pat = term}                      - term abbreviation (HO matching)
   899   @{note name = fact}                     - fact abbreviation
   900   @{thm fact}                             - singleton fact (with attributes)
   901   @{thms fact}                            - general fact (with attributes)
   902   @{lemma prop by method}                 - singleton goal
   903   @{lemma prop by meth1 meth2}            - singleton goal
   904   @{lemma prop1 ... propN by method}      - general goal
   905   @{lemma prop1 ... propN by meth1 meth2} - general goal
   906   @{lemma (open) ...}                     - open derivation
   907 
   908 
   909 *** System ***
   910 
   911 * The Isabelle "emacs" tool provides a specific interface to invoke
   912 Proof General / Emacs, with more explicit failure if that is not
   913 installed (the old isabelle-interface script silently falls back on
   914 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   915 installation location of the Proof General distribution.
   916 
   917 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   918 the Isabelle process into a JVM/Scala application.  See
   919 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   920 process wrapper has been discontinued.)
   921 
   922 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   923 
   924 * Various status messages (with exact source position information) are
   925 emitted, if proper markup print mode is enabled.  This allows
   926 user-interface components to provide detailed feedback on internal
   927 prover operations.
   928 
   929 
   930 
   931 New in Isabelle2008 (June 2008)
   932 -------------------------------
   933 
   934 *** General ***
   935 
   936 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   937 and updated, with formally checked references as hyperlinks.
   938 
   939 * Theory loader: use_thy (and similar operations) no longer set the
   940 implicit ML context, which was occasionally hard to predict and in
   941 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   942 provides a proper context already.
   943 
   944 * Theory loader: old-style ML proof scripts being *attached* to a thy
   945 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   946 'use' within a theory file will do the job.
   947 
   948 * Name space merge now observes canonical order, i.e. the second space
   949 is inserted into the first one, while existing entries in the first
   950 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   951 swap theory imports.
   952 
   953 * Syntax: symbol \<chi> is now considered a letter.  Potential
   954 INCOMPATIBILITY in identifier syntax etc.
   955 
   956 * Outer syntax: string tokens no longer admit escaped white space,
   957 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   958 white space without escapes.
   959 
   960 * Outer syntax: string tokens may contain arbitrary character codes
   961 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   962 "foo_bar".
   963 
   964 
   965 *** Pure ***
   966 
   967 * Context-dependent token translations.  Default setup reverts locally
   968 fixed variables, and adds hilite markup for undeclared frees.
   969 
   970 * Unused theorems can be found using the new command 'unused_thms'.
   971 There are three ways of invoking it:
   972 
   973 (1) unused_thms
   974      Only finds unused theorems in the current theory.
   975 
   976 (2) unused_thms thy_1 ... thy_n -
   977      Finds unused theorems in the current theory and all of its ancestors,
   978      excluding the theories thy_1 ... thy_n and all of their ancestors.
   979 
   980 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   981      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   982      their ancestors, excluding the theories thy_1 ... thy_n and all of
   983      their ancestors.
   984 
   985 In order to increase the readability of the list produced by
   986 unused_thms, theorems that have been created by a particular instance
   987 of a theory command such as 'inductive' or 'function' are considered
   988 to belong to the same "group", meaning that if at least one theorem in
   989 this group is used, the other theorems in the same group are no longer
   990 reported as unused.  Moreover, if all theorems in the group are
   991 unused, only one theorem in the group is displayed.
   992 
   993 Note that proof objects have to be switched on in order for
   994 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   995 usually the case when using Proof General with the default settings).
   996 
   997 * Authentic naming of facts disallows ad-hoc overwriting of previous
   998 theorems within the same name space.  INCOMPATIBILITY, need to remove
   999 duplicate fact bindings, or even accidental fact duplications.  Note
  1000 that tools may maintain dynamically scoped facts systematically, using
  1001 PureThy.add_thms_dynamic.
  1002 
  1003 * Command 'hide' now allows to hide from "fact" name space as well.
  1004 
  1005 * Eliminated destructive theorem database, simpset, claset, and
  1006 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
  1007 update of theories within ML code.
  1008 
  1009 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
  1010 INCOMPATIBILITY, object-logics depending on former Pure require
  1011 additional setup PureThy.old_appl_syntax_setup; object-logics
  1012 depending on former CPure need to refer to Pure.
  1013 
  1014 * Commands 'use' and 'ML' are now purely functional, operating on
  1015 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
  1016 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
  1017 INCOMPATIBILITY.
  1018 
  1019 * Command 'setup': discontinued implicit version with ML reference.
  1020 
  1021 * Instantiation target allows for simultaneous specification of class
  1022 instance operations together with an instantiation proof.
  1023 Type-checking phase allows to refer to class operations uniformly.
  1024 See src/HOL/Complex/Complex.thy for an Isar example and
  1025 src/HOL/Library/Eval.thy for an ML example.
  1026 
  1027 * Indexing of literal facts: be more serious about including only
  1028 facts from the visible specification/proof context, but not the
  1029 background context (locale etc.).  Affects `prop` notation and method
  1030 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
  1031 situations.
  1032 
  1033 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
  1034 "(open)" option, which used to expose internal bound variables to the
  1035 proof text.
  1036 
  1037 * Isar statements: removed obsolete case "rule_context".
  1038 INCOMPATIBILITY, better use explicit fixes/assumes.
  1039 
  1040 * Locale proofs: default proof step now includes 'unfold_locales';
  1041 hence 'proof' without argument may be used to unfold locale
  1042 predicates.
  1043 
  1044 
  1045 *** Document preparation ***
  1046 
  1047 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
  1048 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
  1049 obsolete thumbpdf setup (contemporary PDF viewers do this on the
  1050 spot); renamed link color from "darkblue" to "linkcolor" (default
  1051 value unchanged, can be redefined via \definecolor); no longer sets
  1052 "a4paper" option (unnecessary or even intrusive).
  1053 
  1054 * Antiquotation @{lemma A method} proves proposition A by the given
  1055 method (either a method name or a method name plus (optional) method
  1056 arguments in parentheses) and prints A just like @{prop A}.
  1057 
  1058 
  1059 *** HOL ***
  1060 
  1061 * New primrec package.  Specification syntax conforms in style to
  1062 definition/function/....  No separate induction rule is provided.  The
  1063 "primrec" command distinguishes old-style and new-style specifications
  1064 by syntax.  The former primrec package is now named OldPrimrecPackage.
  1065 When adjusting theories, beware: constants stemming from new-style
  1066 primrec specifications have authentic syntax.
  1067 
  1068 * Metis prover is now an order of magnitude faster, and also works
  1069 with multithreading.
  1070 
  1071 * Metis: the maximum number of clauses that can be produced from a
  1072 theorem is now given by the attribute max_clauses.  Theorems that
  1073 exceed this number are ignored, with a warning printed.
  1074 
  1075 * Sledgehammer no longer produces structured proofs by default. To
  1076 enable, declare [[sledgehammer_full = true]].  Attributes
  1077 reconstruction_modulus, reconstruction_sorts renamed
  1078 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
  1079 
  1080 * Method "induct_scheme" derives user-specified induction rules
  1081 from well-founded induction and completeness of patterns. This factors
  1082 out some operations that are done internally by the function package
  1083 and makes them available separately.  See
  1084 src/HOL/ex/Induction_Scheme.thy for examples.
  1085 
  1086 * More flexible generation of measure functions for termination
  1087 proofs: Measure functions can be declared by proving a rule of the
  1088 form "is_measure f" and giving it the [measure_function] attribute.
  1089 The "is_measure" predicate is logically meaningless (always true), and
  1090 just guides the heuristic.  To find suitable measure functions, the
  1091 termination prover sets up the goal "is_measure ?f" of the appropriate
  1092 type and generates all solutions by prolog-style backwards proof using
  1093 the declared rules.
  1094 
  1095 This setup also deals with rules like 
  1096 
  1097   "is_measure f ==> is_measure (list_size f)"
  1098 
  1099 which accommodates nested datatypes that recurse through lists.
  1100 Similar rules are predeclared for products and option types.
  1101 
  1102 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
  1103 
  1104   INCOMPATIBILITIES:
  1105 
  1106   - Definitions of overloaded constants on sets have to be replaced by
  1107     definitions on => and bool.
  1108 
  1109   - Some definitions of overloaded operators on sets can now be proved
  1110     using the definitions of the operators on => and bool.  Therefore,
  1111     the following theorems have been renamed:
  1112 
  1113       subset_def   -> subset_eq
  1114       psubset_def  -> psubset_eq
  1115       set_diff_def -> set_diff_eq
  1116       Compl_def    -> Compl_eq
  1117       Sup_set_def  -> Sup_set_eq
  1118       Inf_set_def  -> Inf_set_eq
  1119       sup_set_def  -> sup_set_eq
  1120       inf_set_def  -> inf_set_eq
  1121 
  1122   - Due to the incompleteness of the HO unification algorithm, some
  1123     rules such as subst may require manual instantiation, if some of
  1124     the unknowns in the rule is a set.
  1125 
  1126   - Higher order unification and forward proofs:
  1127     The proof pattern
  1128 
  1129       have "P (S::'a set)" <...>
  1130       then have "EX S. P S" ..
  1131 
  1132     no longer works (due to the incompleteness of the HO unification
  1133     algorithm) and must be replaced by the pattern
  1134 
  1135       have "EX S. P S"
  1136       proof
  1137         show "P S" <...>
  1138       qed
  1139 
  1140   - Calculational reasoning with subst (or similar rules):
  1141     The proof pattern
  1142 
  1143       have "P (S::'a set)" <...>
  1144       also have "S = T" <...>
  1145       finally have "P T" .
  1146 
  1147     no longer works (for similar reasons as the previous example) and
  1148     must be replaced by something like
  1149 
  1150       have "P (S::'a set)" <...>
  1151       moreover have "S = T" <...>
  1152       ultimately have "P T" by simp
  1153 
  1154   - Tactics or packages written in ML code:
  1155     Code performing pattern matching on types via
  1156 
  1157       Type ("set", [T]) => ...
  1158 
  1159     must be rewritten. Moreover, functions like strip_type or
  1160     binder_types no longer return the right value when applied to a
  1161     type of the form
  1162 
  1163       T1 => ... => Tn => U => bool
  1164 
  1165     rather than
  1166 
  1167       T1 => ... => Tn => U set
  1168 
  1169 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1170 Wellfounded_Relations to theory Wellfounded.
  1171 
  1172 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1173 
  1174 * Class finite no longer treats UNIV as class parameter.  Use class
  1175 enum from theory Library/Enum instead to achieve a similar effect.
  1176 INCOMPATIBILITY.
  1177 
  1178 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1179 and "Cons".  INCOMPATIBILITY.
  1180 
  1181 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1182 Potential INCOMPATIBILITY.
  1183 
  1184 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1185 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1186 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1187 
  1188 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1189 the same name in theory Orderings:
  1190 
  1191   less_trans
  1192   less_linear
  1193   le_imp_less_or_eq
  1194   le_less_trans
  1195   less_le_trans
  1196   less_not_sym
  1197   less_asym
  1198 
  1199 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1200 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1201 and different variable names.
  1202 
  1203 * Library/Option_ord.thy: Canonical order on option type.
  1204 
  1205 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1206 finite maps.
  1207 
  1208 * Library/Countable.thy: Type class for countable types.
  1209 
  1210 * Theory Int: The representation of numerals has changed.  The infix
  1211 operator BIT and the bit datatype with constructors B0 and B1 have
  1212 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1213 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1214 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1215 accordingly.
  1216 
  1217 * Theory Nat: definition of <= and < on natural numbers no longer
  1218 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1219 le_def and less_def have disappeared.  Consider lemmas not_less
  1220 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1221 
  1222 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1223 (whose purpose mainly is for various fold_set functionals) have been
  1224 abandoned in favor of the existing algebraic classes
  1225 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1226 lower_semilattice (resp. upper_semilattice) and linorder.
  1227 INCOMPATIBILITY.
  1228 
  1229 * Theory Transitive_Closure: induct and cases rules now declare proper
  1230 case_names ("base" and "step").  INCOMPATIBILITY.
  1231 
  1232 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1233 lattices.  The form set-specific version is available as
  1234 Inductive.lfp_ordinal_induct_set.
  1235 
  1236 * Renamed theorems "power.simps" to "power_int.simps".
  1237 INCOMPATIBILITY.
  1238 
  1239 * Class semiring_div provides basic abstract properties of semirings
  1240 with division and modulo operations.  Subsumes former class dvd_mod.
  1241 
  1242 * Merged theories IntDef, Numeral and IntArith into unified theory
  1243 Int.  INCOMPATIBILITY.
  1244 
  1245 * Theory Library/Code_Index: type "index" now represents natural
  1246 numbers rather than integers.  INCOMPATIBILITY.
  1247 
  1248 * New class "uminus" with operation "uminus" (split of from class
  1249 "minus" which now only has operation "minus", binary).
  1250 INCOMPATIBILITY.
  1251 
  1252 * Constants "card", "internal_split", "option_map" now with authentic
  1253 syntax.  INCOMPATIBILITY.
  1254 
  1255 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1256 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1257 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1258 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1259 Sup_set_def, le_def, less_def, option_map_def now with object
  1260 equality.  INCOMPATIBILITY.
  1261 
  1262 * Records. Removed K_record, and replaced it by pure lambda term
  1263 %x. c. The simplifier setup is now more robust against eta expansion.
  1264 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1265 
  1266 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1267 
  1268 * Library/ListVector: new theory of arithmetic vector operations.
  1269 
  1270 * Library/Order_Relation: new theory of various orderings as sets of
  1271 pairs.  Defines preorders, partial orders, linear orders and
  1272 well-orders on sets and on types.
  1273 
  1274 
  1275 *** ZF ***
  1276 
  1277 * Renamed some theories to allow to loading both ZF and HOL in the
  1278 same session:
  1279 
  1280   Datatype  -> Datatype_ZF
  1281   Inductive -> Inductive_ZF
  1282   Int       -> Int_ZF
  1283   IntDiv    -> IntDiv_ZF
  1284   Nat       -> Nat_ZF
  1285   List      -> List_ZF
  1286   Main      -> Main_ZF
  1287 
  1288 INCOMPATIBILITY: ZF theories that import individual theories below
  1289 Main might need to be adapted.  Regular theory Main is still
  1290 available, as trivial extension of Main_ZF.
  1291 
  1292 
  1293 *** ML ***
  1294 
  1295 * ML within Isar: antiquotation @{const name} or @{const
  1296 name(typargs)} produces statically-checked Const term.
  1297 
  1298 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1299 (of the same name).  Removed obsolete print command.
  1300 
  1301 * Removed obsolete "use_legacy_bindings" function.
  1302 
  1303 * The ``print mode'' is now a thread-local value derived from a global
  1304 template (the former print_mode reference), thus access becomes
  1305 non-critical.  The global print_mode reference is for session
  1306 management only; user-code should use print_mode_value,
  1307 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1308 
  1309 * Functions system/system_out provide a robust way to invoke external
  1310 shell commands, with propagation of interrupts (requires Poly/ML
  1311 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1312 
  1313 
  1314 *** System ***
  1315 
  1316 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1317 in accordance with Proof General 3.7, which prefers GNU emacs.
  1318 
  1319 * isatool tty runs Isabelle process with plain tty interaction;
  1320 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1321 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1322 
  1323 * isatool browser now works with Cygwin as well, using general
  1324 "javapath" function defined in Isabelle process environment.
  1325 
  1326 * YXML notation provides a simple and efficient alternative to
  1327 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1328 isatool yxml as described in the Isabelle system manual.
  1329 
  1330 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1331 provides general wrapper for managing an Isabelle process in a robust
  1332 fashion, with ``cooked'' output from stdin/stderr.
  1333 
  1334 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1335 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1336 
  1337 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1338 way of changing the user's settings is via
  1339 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1340 script.
  1341 
  1342 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1343 cores of the underlying machine, which is a good starting point for
  1344 optimal performance tuning.  The corresponding usedir option -M allows
  1345 "max" as an alias for "0".  WARNING: does not work on certain versions
  1346 of Mac OS (with Poly/ML 5.1).
  1347 
  1348 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1349 adverse effect of Isabelle flooding interactive front-ends (notably
  1350 ProofGeneral / XEmacs).
  1351 
  1352 
  1353 
  1354 New in Isabelle2007 (November 2007)
  1355 -----------------------------------
  1356 
  1357 *** General ***
  1358 
  1359 * More uniform information about legacy features, notably a
  1360 warning/error of "Legacy feature: ...", depending on the state of the
  1361 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1362 legacy features will disappear eventually.
  1363 
  1364 * Theory syntax: the header format ``theory A = B + C:'' has been
  1365 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1366 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1367 
  1368 * Theory syntax: the old non-Isar theory file format has been
  1369 discontinued altogether.  Note that ML proof scripts may still be used
  1370 with Isar theories; migration is usually quite simple with the ML
  1371 function use_legacy_bindings.  INCOMPATIBILITY.
  1372 
  1373 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1374 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1375 quotes.
  1376 
  1377 * Theory loader: be more serious about observing the static theory
  1378 header specifications (including optional directories), but not the
  1379 accidental file locations of previously successful loads.  The strict
  1380 update policy of former update_thy is now already performed by
  1381 use_thy, so the former has been removed; use_thys updates several
  1382 theories simultaneously, just as 'imports' within a theory header
  1383 specification, but without merging the results.  Potential
  1384 INCOMPATIBILITY: may need to refine theory headers and commands
  1385 ROOT.ML which depend on load order.
  1386 
  1387 * Theory loader: optional support for content-based file
  1388 identification, instead of the traditional scheme of full physical
  1389 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1390 (cf. the system manual).  The new scheme allows to work with
  1391 non-finished theories in persistent session images, such that source
  1392 files may be moved later on without requiring reloads.
  1393 
  1394 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1395 file (with the same base name as the theory) are considered a legacy
  1396 feature, which will disappear eventually. Even now, the theory loader
  1397 no longer maintains dependencies on such files.
  1398 
  1399 * Syntax: the scope for resolving ambiguities via type-inference is
  1400 now limited to individual terms, instead of whole simultaneous
  1401 specifications as before. This greatly reduces the complexity of the
  1402 syntax module and improves flexibility by separating parsing and
  1403 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1404 'fixes' etc.) are required in rare situations.
  1405 
  1406 * Syntax: constants introduced by new-style packages ('definition',
  1407 'abbreviation' etc.) are passed through the syntax module in
  1408 ``authentic mode''. This means that associated mixfix annotations
  1409 really stick to such constants, independently of potential name space
  1410 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1411 trees are represented slightly differently, may need to adapt syntax
  1412 translations accordingly. Use CONST marker in 'translations' and
  1413 @{const_syntax} antiquotation in 'parse_translation' etc.
  1414 
  1415 * Legacy goal package: reduced interface to the bare minimum required
  1416 to keep existing proof scripts running.  Most other user-level
  1417 functions are now part of the OldGoals structure, which is *not* open
  1418 by default (consider isatool expandshort before open OldGoals).
  1419 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1420 these tend to cause confusion about the actual goal (!) context being
  1421 used here, which is not necessarily the same as the_context().
  1422 
  1423 * Command 'find_theorems': supports "*" wild-card in "name:"
  1424 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1425 support a specific search form (see ProofGeneral/CHANGES).
  1426 
  1427 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1428 by default, which means that "prems" (and also "fixed variables") are
  1429 suppressed from proof state output.  Note that the ProofGeneral
  1430 settings mechanism allows to change and save options persistently, but
  1431 older versions of Isabelle will fail to start up if a negative prems
  1432 limit is imposed.
  1433 
  1434 * Local theory targets may be specified by non-nested blocks of
  1435 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1436 contain definitions, theorems etc., including any derived mechanism
  1437 that has been implemented on top of these primitives.  This concept
  1438 generalizes the existing ``theorem (in ...)'' towards more versatility
  1439 and scalability.
  1440 
  1441 * Proof General interface: proper undo of final 'end' command;
  1442 discontinued Isabelle/classic mode (ML proof scripts).
  1443 
  1444 
  1445 *** Document preparation ***
  1446 
  1447 * Added antiquotation @{theory name} which prints the given name,
  1448 after checking that it refers to a valid ancestor theory in the
  1449 current context.
  1450 
  1451 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1452 check the given source text as ML type/structure, printing verbatim.
  1453 
  1454 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1455 "c args == rhs" given in the current context.  (Any number of
  1456 arguments may be given on the LHS.)
  1457 
  1458 
  1459 *** Pure ***
  1460 
  1461 * The 'class' package offers a combination of axclass and locale to
  1462 achieve Haskell-like type classes in Isabelle.  Definitions and
  1463 theorems within a class context produce both relative results (with
  1464 implicit parameters according to the locale context), and polymorphic
  1465 constants with qualified polymorphism (according to the class
  1466 context).  Within the body context of a 'class' target, a separate
  1467 syntax layer ("user space type system") takes care of converting
  1468 between global polymorphic consts and internal locale representation.
  1469 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1470 "isatool doc classes" provides a tutorial.
  1471 
  1472 * Generic code generator framework allows to generate executable
  1473 code for ML and Haskell (including Isabelle classes).  A short usage
  1474 sketch:
  1475 
  1476     internal compilation:
  1477         export_code <list of constants (term syntax)> in SML
  1478     writing SML code to a file:
  1479         export_code <list of constants (term syntax)> in SML <filename>
  1480     writing OCaml code to a file:
  1481         export_code <list of constants (term syntax)> in OCaml <filename>
  1482     writing Haskell code to a bunch of files:
  1483         export_code <list of constants (term syntax)> in Haskell <filename>
  1484 
  1485     evaluating closed propositions to True/False using code generation:
  1486         method ``eval''
  1487 
  1488 Reasonable default setup of framework in HOL.
  1489 
  1490 Theorem attributs for selecting and transforming function equations theorems:
  1491 
  1492     [code fun]:        select a theorem as function equation for a specific constant
  1493     [code fun del]:    deselect a theorem as function equation for a specific constant
  1494     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1495     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1496 
  1497 User-defined serializations (target in {SML, OCaml, Haskell}):
  1498 
  1499     code_const <and-list of constants (term syntax)>
  1500       {(target) <and-list of const target syntax>}+
  1501 
  1502     code_type <and-list of type constructors>
  1503       {(target) <and-list of type target syntax>}+
  1504 
  1505     code_instance <and-list of instances>
  1506       {(target)}+
  1507         where instance ::= <type constructor> :: <class>
  1508 
  1509     code_class <and_list of classes>
  1510       {(target) <and-list of class target syntax>}+
  1511         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1512 
  1513 code_instance and code_class only are effective to target Haskell.
  1514 
  1515 For example usage see src/HOL/ex/Codegenerator.thy and
  1516 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1517 generation from Isabelle/HOL theories is available via "isatool doc
  1518 codegen".
  1519 
  1520 * Code generator: consts in 'consts_code' Isar commands are now
  1521 referred to by usual term syntax (including optional type
  1522 annotations).
  1523 
  1524 * Command 'no_translations' removes translation rules from theory
  1525 syntax.
  1526 
  1527 * Overloaded definitions are now actually checked for acyclic
  1528 dependencies.  The overloading scheme is slightly more general than
  1529 that of Haskell98, although Isabelle does not demand an exact
  1530 correspondence to type class and instance declarations.
  1531 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1532 exotic versions of overloading -- at the discretion of the user!
  1533 
  1534 Polymorphic constants are represented via type arguments, i.e. the
  1535 instantiation that matches an instance against the most general
  1536 declaration given in the signature.  For example, with the declaration
  1537 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1538 as c(nat).  Overloading is essentially simultaneous structural
  1539 recursion over such type arguments.  Incomplete specification patterns
  1540 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1541 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1542 Command 'print_theory' outputs the normalized system of recursive
  1543 equations, see section "definitions".
  1544 
  1545 * Configuration options are maintained within the theory or proof
  1546 context (with name and type bool/int/string), providing a very simple
  1547 interface to a poor-man's version of general context data.  Tools may
  1548 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1549 these values using Config.get etc.  Users may change options via an
  1550 associated attribute of the same name.  This form of context
  1551 declaration works particularly well with commands 'declare' or
  1552 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1553 very easy to avoid global references, which would not observe Isar
  1554 toplevel undo/redo and fail to work with multithreading.
  1555 
  1556 Various global ML references of Pure and HOL have been turned into
  1557 configuration options:
  1558 
  1559   Unify.search_bound		unify_search_bound
  1560   Unify.trace_bound		unify_trace_bound
  1561   Unify.trace_simp		unify_trace_simp
  1562   Unify.trace_types		unify_trace_types
  1563   Simplifier.simp_depth_limit	simp_depth_limit
  1564   Blast.depth_limit		blast_depth_limit
  1565   DatatypeProp.dtK		datatype_distinctness_limit
  1566   fast_arith_neq_limit  	fast_arith_neq_limit
  1567   fast_arith_split_limit	fast_arith_split_limit
  1568 
  1569 * Named collections of theorems may be easily installed as context
  1570 data using the functor NamedThmsFun (see also
  1571 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1572 attributes; there is also a toplevel print command.  This facility is
  1573 just a common case of general context data, which is the preferred way
  1574 for anything more complex than just a list of facts in canonical
  1575 order.
  1576 
  1577 * Isar: command 'declaration' augments a local theory by generic
  1578 declaration functions written in ML.  This enables arbitrary content
  1579 being added to the context, depending on a morphism that tells the
  1580 difference of the original declaration context wrt. the application
  1581 context encountered later on.
  1582 
  1583 * Isar: proper interfaces for simplification procedures.  Command
  1584 'simproc_setup' declares named simprocs (with match patterns, and body
  1585 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1586 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1587 
  1588 * Isar: an extra pair of brackets around attribute declarations
  1589 abbreviates a theorem reference involving an internal dummy fact,
  1590 which will be ignored later --- only the effect of the attribute on
  1591 the background context will persist.  This form of in-place
  1592 declarations is particularly useful with commands like 'declare' and
  1593 'using', for example ``have A using [[simproc a]] by simp''.
  1594 
  1595 * Isar: method "assumption" (and implicit closing of subproofs) now
  1596 takes simple non-atomic goal assumptions into account: after applying
  1597 an assumption as a rule the resulting subgoals are solved by atomic
  1598 assumption steps.  This is particularly useful to finish 'obtain'
  1599 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1600 without referring to the original premise "!!x. P x ==> thesis" in the
  1601 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1602 more permissive.
  1603 
  1604 * Isar: implicit use of prems from the Isar proof context is
  1605 considered a legacy feature.  Common applications like ``have A .''
  1606 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1607 referencing facts explicitly here improves readability and
  1608 maintainability of proof texts.
  1609 
  1610 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1611 the obtained context from the course of reasoning!  For example:
  1612 
  1613   assume "EX x y. A x & B y"   -- "any previous fact"
  1614   then guess x and y by clarify
  1615 
  1616 This technique is potentially adventurous, depending on the facts and
  1617 proof tools being involved here.
  1618 
  1619 * Isar: known facts from the proof context may be specified as literal
  1620 propositions, using ASCII back-quote syntax.  This works wherever
  1621 named facts used to be allowed so far, in proof commands, proof
  1622 methods, attributes etc.  Literal facts are retrieved from the context
  1623 according to unification of type and term parameters.  For example,
  1624 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1625 theorems in the current context, then these are valid literal facts:
  1626 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1627 
  1628 There is also a proof method "fact" which does the same composition
  1629 for explicit goal states, e.g. the following proof texts coincide with
  1630 certain special cases of literal facts:
  1631 
  1632   have "A" by fact                 ==  note `A`
  1633   have "A ==> B" by fact           ==  note `A ==> B`
  1634   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1635   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1636 
  1637 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1638 outer syntax.  Thus symbolic identifiers may be used without
  1639 additional white space in declarations like this: ``assume *: A''.
  1640 
  1641 * Isar: 'print_facts' prints all local facts of the current context,
  1642 both named and unnamed ones.
  1643 
  1644 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1645 
  1646   def x == "t" and y == "u"
  1647 
  1648 * Isar: added command 'unfolding', which is structurally similar to
  1649 'using', but affects both the goal state and facts by unfolding given
  1650 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1651 'unfolded' attribute may be replaced by first-class proof text.
  1652 
  1653 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1654 and command 'unfolding' now all support object-level equalities
  1655 (potentially conditional).  The underlying notion of rewrite rule is
  1656 analogous to the 'rule_format' attribute, but *not* that of the
  1657 Simplifier (which is usually more generous).
  1658 
  1659 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1660 premises of a theorem by n. Useful in conjunction with drule.
  1661 
  1662 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1663 method expression within a sandbox consisting of the first N
  1664 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1665 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1666 simplifies all new goals that emerge from applying rule foo to the
  1667 originally first one.
  1668 
  1669 * Isar: schematic goals are no longer restricted to higher-order
  1670 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1671 expected.
  1672 
  1673 * Isar: the conclusion of a long theorem statement is now either
  1674 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1675 (essentially a disjunction of cases with local parameters and
  1676 assumptions).  The latter allows to express general elimination rules
  1677 adequately; in this notation common elimination rules look like this:
  1678 
  1679   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1680     assumes "EX x. P x"
  1681     obtains x where "P x"
  1682 
  1683   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1684     assumes "A & B"
  1685     obtains A and B
  1686 
  1687   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1688     assumes "A | B"
  1689     obtains
  1690       A
  1691     | B
  1692 
  1693 The subsequent classical rules even refer to the formal "thesis"
  1694 explicitly:
  1695 
  1696   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1697     obtains "~ thesis"
  1698 
  1699   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1700     obtains "thesis ==> something"
  1701 
  1702 The actual proof of an 'obtains' statement is analogous to that of the
  1703 Isar proof element 'obtain', only that there may be several cases.
  1704 Optional case names may be specified in parentheses; these will be
  1705 available both in the present proof and as annotations in the
  1706 resulting rule, for later use with the 'cases' method (cf. attribute
  1707 case_names).
  1708 
  1709 * Isar: the assumptions of a long theorem statement are available as
  1710 "assms" fact in the proof context.  This is more appropriate than the
  1711 (historical) "prems", which refers to all assumptions of the current
  1712 context, including those from the target locale, proof body etc.
  1713 
  1714 * Isar: 'print_statement' prints theorems from the current theory or
  1715 proof context in long statement form, according to the syntax of a
  1716 top-level lemma.
  1717 
  1718 * Isar: 'obtain' takes an optional case name for the local context
  1719 introduction rule (default "that").
  1720 
  1721 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1722 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1723 to occur.
  1724 
  1725 * Pure: syntax "CONST name" produces a fully internalized constant
  1726 according to the current context.  This is particularly useful for
  1727 syntax translations that should refer to internal constant
  1728 representations independently of name spaces.
  1729 
  1730 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1731 instead of "FOO ". This allows multiple binder declarations to coexist
  1732 in the same context.  INCOMPATIBILITY.
  1733 
  1734 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1735 primitive that also works in a locale context (both for constants and
  1736 fixed variables). Type declaration and internal syntactic representation
  1737 of given constants retrieved from the context. Likewise, the
  1738 'no_notation' command allows to remove given syntax annotations from the
  1739 current context.
  1740 
  1741 * Isar/locales: new derived specification elements 'axiomatization',
  1742 'definition', 'abbreviation', which support type-inference, admit
  1743 object-level specifications (equality, equivalence).  See also the
  1744 isar-ref manual.  Examples:
  1745 
  1746   axiomatization
  1747     eq  (infix "===" 50) where
  1748     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1749 
  1750   definition "f x y = x + y + 1"
  1751   definition g where "g x = f x x"
  1752 
  1753   abbreviation
  1754     neq  (infix "=!=" 50) where
  1755     "x =!= y == ~ (x === y)"
  1756 
  1757 These specifications may be also used in a locale context.  Then the
  1758 constants being introduced depend on certain fixed parameters, and the
  1759 constant name is qualified by the locale base name.  An internal
  1760 abbreviation takes care for convenient input and output, making the
  1761 parameters implicit and using the original short name.  See also
  1762 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1763 entities from a monomorphic theory.
  1764 
  1765 Presently, abbreviations are only available 'in' a target locale, but
  1766 not inherited by general import expressions.  Also note that
  1767 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1768 'translations' in common applications.  The "no_abbrevs" print mode
  1769 prevents folding of abbreviations in term output.
  1770 
  1771 Concrete syntax is attached to specified constants in internal form,
  1772 independently of name spaces.  The parse tree representation is
  1773 slightly different -- use 'notation' instead of raw 'syntax', and
  1774 'translations' with explicit "CONST" markup to accommodate this.
  1775 
  1776 * Pure/Isar: unified syntax for new-style specification mechanisms
  1777 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1778 full type inference and dummy patterns ("_").  For example:
  1779 
  1780   definition "K x _ = x"
  1781 
  1782   inductive conj for A B
  1783   where "A ==> B ==> conj A B"
  1784 
  1785 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1786 the current context.  Print mode "no_abbrevs" prevents inversion of
  1787 abbreviations on output.
  1788 
  1789 * Isar/locales: improved parameter handling: use of locales "var" and
  1790 "struct" no longer necessary; - parameter renamings are no longer
  1791 required to be injective.  For example, this allows to define
  1792 endomorphisms as locale endom = homom mult mult h.
  1793 
  1794 * Isar/locales: changed the way locales with predicates are defined.
  1795 Instead of accumulating the specification, the imported expression is
  1796 now an interpretation.  INCOMPATIBILITY: different normal form of
  1797 locale expressions.  In particular, in interpretations of locales with
  1798 predicates, goals repesenting already interpreted fragments are not
  1799 removed automatically.  Use methods `intro_locales' and
  1800 `unfold_locales'; see below.
  1801 
  1802 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1803 provide backward reasoning on locales predicates.  The methods are
  1804 aware of interpretations and discharge corresponding goals.
  1805 `intro_locales' is less aggressive then `unfold_locales' and does not
  1806 unfold predicates to assumptions.
  1807 
  1808 * Isar/locales: the order in which locale fragments are accumulated
  1809 has changed.  This enables to override declarations from fragments due
  1810 to interpretations -- for example, unwanted simp rules.
  1811 
  1812 * Isar/locales: interpretation in theories and proof contexts has been
  1813 extended.  One may now specify (and prove) equations, which are
  1814 unfolded in interpreted theorems.  This is useful for replacing
  1815 defined concepts (constants depending on locale parameters) by
  1816 concepts already existing in the target context.  Example:
  1817 
  1818   interpretation partial_order ["op <= :: [int, int] => bool"]
  1819     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1820 
  1821 Typically, the constant `partial_order.less' is created by a
  1822 definition specification element in the context of locale
  1823 partial_order.
  1824 
  1825 * Method "induct": improved internal context management to support
  1826 local fixes and defines on-the-fly. Thus explicit meta-level
  1827 connectives !!  and ==> are rarely required anymore in inductive goals
  1828 (using object-logic connectives for this purpose has been long
  1829 obsolete anyway). Common proof patterns are explained in
  1830 src/HOL/Induct/Common_Patterns.thy, see also
  1831 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1832 examples.
  1833 
  1834 * Method "induct": improved handling of simultaneous goals. Instead of
  1835 introducing object-level conjunction, the statement is now split into
  1836 several conclusions, while the corresponding symbolic cases are nested
  1837 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1838 see src/HOL/Induct/Common_Patterns.thy, for example.
  1839 
  1840 * Method "induct": mutual induction rules are now specified as a list
  1841 of rule sharing the same induction cases. HOL packages usually provide
  1842 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1843 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1844 mutual induction rules differently, i.e. like this:
  1845 
  1846   (induct rule: foo_bar.inducts)
  1847   (induct set: foo bar)
  1848   (induct pred: foo bar)
  1849   (induct type: foo bar)
  1850 
  1851 The ML function ProjectRule.projections turns old-style rules into the
  1852 new format.
  1853 
  1854 * Method "coinduct": dual of induction, see
  1855 src/HOL/Library/Coinductive_List.thy for various examples.
  1856 
  1857 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1858 considered a legacy feature.
  1859 
  1860 * Attribute "symmetric" produces result with standardized schematic
  1861 variables (index 0).  Potential INCOMPATIBILITY.
  1862 
  1863 * Simplifier: by default the simplifier trace only shows top level
  1864 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1865 default. Thus there is less danger of being flooded by the trace. The
  1866 trace indicates where parts have been suppressed.
  1867   
  1868 * Provers/classical: removed obsolete classical version of elim_format
  1869 attribute; classical elim/dest rules are now treated uniformly when
  1870 manipulating the claset.
  1871 
  1872 * Provers/classical: stricter checks to ensure that supplied intro,
  1873 dest and elim rules are well-formed; dest and elim rules must have at
  1874 least one premise.
  1875 
  1876 * Provers/classical: attributes dest/elim/intro take an optional
  1877 weight argument for the rule (just as the Pure versions).  Weights are
  1878 ignored by automated tools, but determine the search order of single
  1879 rule steps.
  1880 
  1881 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1882 where the body does not mention the bound variable.  Note that dummy
  1883 patterns implicitly depend on their context of bounds, which makes
  1884 "{_. _}" match any set comprehension as expected.  Potential
  1885 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1886 constant "_idtdummy" in the binding position.
  1887 
  1888 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1889 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1890 for example "A -> B" => "Pi A (%_. B)".
  1891 
  1892 * Pure: 'class_deps' command visualizes the subclass relation, using
  1893 the graph browser tool.
  1894 
  1895 * Pure: 'print_theory' now suppresses certain internal declarations by
  1896 default; use '!' option for full details.
  1897 
  1898 
  1899 *** HOL ***
  1900 
  1901 * Method "metis" proves goals by applying the Metis general-purpose
  1902 resolution prover (see also http://gilith.com/software/metis/).
  1903 Examples are in the directory MetisExamples.  WARNING: the
  1904 Isabelle/HOL-Metis integration does not yet work properly with
  1905 multi-threading.
  1906   
  1907 * Command 'sledgehammer' invokes external automatic theorem provers as
  1908 background processes.  It generates calls to the "metis" method if
  1909 successful. These can be pasted into the proof.  Users do not have to
  1910 wait for the automatic provers to return.  WARNING: does not really
  1911 work with multi-threading.
  1912 
  1913 * New "auto_quickcheck" feature tests outermost goal statements for
  1914 potential counter-examples.  Controlled by ML references
  1915 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1916 5000 milliseconds).  Fails silently if statements is outside of
  1917 executable fragment, or any other codgenerator problem occurs.
  1918 
  1919 * New constant "undefined" with axiom "undefined x = undefined".
  1920 
  1921 * Added class "HOL.eq", allowing for code generation with polymorphic
  1922 equality.
  1923 
  1924 * Some renaming of class constants due to canonical name prefixing in
  1925 the new 'class' package:
  1926 
  1927     HOL.abs ~> HOL.abs_class.abs
  1928     HOL.divide ~> HOL.divide_class.divide
  1929     0 ~> HOL.zero_class.zero
  1930     1 ~> HOL.one_class.one
  1931     op + ~> HOL.plus_class.plus
  1932     op - ~> HOL.minus_class.minus
  1933     uminus ~> HOL.minus_class.uminus
  1934     op * ~> HOL.times_class.times
  1935     op < ~> HOL.ord_class.less
  1936     op <= > HOL.ord_class.less_eq
  1937     Nat.power ~> Power.power_class.power
  1938     Nat.size ~> Nat.size_class.size
  1939     Numeral.number_of ~> Numeral.number_class.number_of
  1940     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1941     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1942     Orderings.min ~> Orderings.ord_class.min
  1943     Orderings.max ~> Orderings.ord_class.max
  1944     Divides.op div ~> Divides.div_class.div
  1945     Divides.op mod ~> Divides.div_class.mod
  1946     Divides.op dvd ~> Divides.div_class.dvd
  1947 
  1948 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1949 
  1950 a) User-defined constants using any of the names "plus", "minus",
  1951 "times", "less" or "less_eq". The standard syntax translations for
  1952 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1953 names.
  1954 
  1955 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1956 INCOMPATIBILITY: use more specific names.
  1957 
  1958 c) Permutative equations (e.g. "a + b = b + a")
  1959 Since the change of names also changes the order of terms, permutative
  1960 rewrite rules may get applied in a different order. Experience shows
  1961 that this is rarely the case (only two adaptions in the whole Isabelle
  1962 distribution).  INCOMPATIBILITY: rewrite proofs
  1963 
  1964 d) ML code directly refering to constant names
  1965 This in general only affects hand-written proof tactics, simprocs and
  1966 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1967 Consider using @{const_name} antiquotation.
  1968 
  1969 * New class "default" with associated constant "default".
  1970 
  1971 * Function "sgn" is now overloaded and available on int, real, complex
  1972 (and other numeric types), using class "sgn".  Two possible defs of
  1973 sgn are given as equational assumptions in the classes sgn_if and
  1974 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1975 INCOMPATIBILITY.
  1976 
  1977 * Locale "partial_order" now unified with class "order" (cf. theory
  1978 Orderings), added parameter "less".  INCOMPATIBILITY.
  1979 
  1980 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1981 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1982 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1983 
  1984 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1985 changed order of proof goals in instance proofs.
  1986 
  1987 * The transitivity reasoner for partial and linear orders is set up
  1988 for classes "order" and "linorder".  Instances of the reasoner are available
  1989 in all contexts importing or interpreting the corresponding locales.
  1990 Method "order" invokes the reasoner separately; the reasoner
  1991 is also integrated with the Simplifier as a solver.  Diagnostic
  1992 command 'print_orders' shows the available instances of the reasoner
  1993 in the current context.
  1994 
  1995 * Localized monotonicity predicate in theory "Orderings"; integrated
  1996 lemmas max_of_mono and min_of_mono with this predicate.
  1997 INCOMPATIBILITY.
  1998 
  1999 * Formulation of theorem "dense" changed slightly due to integration
  2000 with new class dense_linear_order.
  2001 
  2002 * Uniform lattice theory development in HOL.
  2003 
  2004     constants "meet" and "join" now named "inf" and "sup"
  2005     constant "Meet" now named "Inf"
  2006 
  2007     classes "meet_semilorder" and "join_semilorder" now named
  2008       "lower_semilattice" and "upper_semilattice"
  2009     class "lorder" now named "lattice"
  2010     class "comp_lat" now named "complete_lattice"
  2011 
  2012     Instantiation of lattice classes allows explicit definitions
  2013     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  2014 
  2015   INCOMPATIBILITY.  Theorem renames:
  2016 
  2017     meet_left_le            ~> inf_le1
  2018     meet_right_le           ~> inf_le2
  2019     join_left_le            ~> sup_ge1
  2020     join_right_le           ~> sup_ge2
  2021     meet_join_le            ~> inf_sup_ord
  2022     le_meetI                ~> le_infI
  2023     join_leI                ~> le_supI
  2024     le_meet                 ~> le_inf_iff
  2025     le_join                 ~> ge_sup_conv
  2026     meet_idempotent         ~> inf_idem
  2027     join_idempotent         ~> sup_idem
  2028     meet_comm               ~> inf_commute
  2029     join_comm               ~> sup_commute
  2030     meet_leI1               ~> le_infI1
  2031     meet_leI2               ~> le_infI2
  2032     le_joinI1               ~> le_supI1
  2033     le_joinI2               ~> le_supI2
  2034     meet_assoc              ~> inf_assoc
  2035     join_assoc              ~> sup_assoc
  2036     meet_left_comm          ~> inf_left_commute
  2037     meet_left_idempotent    ~> inf_left_idem
  2038     join_left_comm          ~> sup_left_commute
  2039     join_left_idempotent    ~> sup_left_idem
  2040     meet_aci                ~> inf_aci
  2041     join_aci                ~> sup_aci
  2042     le_def_meet             ~> le_iff_inf
  2043     le_def_join             ~> le_iff_sup
  2044     join_absorp2            ~> sup_absorb2
  2045     join_absorp1            ~> sup_absorb1
  2046     meet_absorp1            ~> inf_absorb1
  2047     meet_absorp2            ~> inf_absorb2
  2048     meet_join_absorp        ~> inf_sup_absorb
  2049     join_meet_absorp        ~> sup_inf_absorb
  2050     distrib_join_le         ~> distrib_sup_le
  2051     distrib_meet_le         ~> distrib_inf_le
  2052 
  2053     add_meet_distrib_left   ~> add_inf_distrib_left
  2054     add_join_distrib_left   ~> add_sup_distrib_left
  2055     is_join_neg_meet        ~> is_join_neg_inf
  2056     is_meet_neg_join        ~> is_meet_neg_sup
  2057     add_meet_distrib_right  ~> add_inf_distrib_right
  2058     add_join_distrib_right  ~> add_sup_distrib_right
  2059     add_meet_join_distribs  ~> add_sup_inf_distribs
  2060     join_eq_neg_meet        ~> sup_eq_neg_inf
  2061     meet_eq_neg_join        ~> inf_eq_neg_sup
  2062     add_eq_meet_join        ~> add_eq_inf_sup
  2063     meet_0_imp_0            ~> inf_0_imp_0
  2064     join_0_imp_0            ~> sup_0_imp_0
  2065     meet_0_eq_0             ~> inf_0_eq_0
  2066     join_0_eq_0             ~> sup_0_eq_0
  2067     neg_meet_eq_join        ~> neg_inf_eq_sup
  2068     neg_join_eq_meet        ~> neg_sup_eq_inf
  2069     join_eq_if              ~> sup_eq_if
  2070 
  2071     mono_meet               ~> mono_inf
  2072     mono_join               ~> mono_sup
  2073     meet_bool_eq            ~> inf_bool_eq
  2074     join_bool_eq            ~> sup_bool_eq
  2075     meet_fun_eq             ~> inf_fun_eq
  2076     join_fun_eq             ~> sup_fun_eq
  2077     meet_set_eq             ~> inf_set_eq
  2078     join_set_eq             ~> sup_set_eq
  2079     meet1_iff               ~> inf1_iff
  2080     meet2_iff               ~> inf2_iff
  2081     meet1I                  ~> inf1I
  2082     meet2I                  ~> inf2I
  2083     meet1D1                 ~> inf1D1
  2084     meet2D1                 ~> inf2D1
  2085     meet1D2                 ~> inf1D2
  2086     meet2D2                 ~> inf2D2
  2087     meet1E                  ~> inf1E
  2088     meet2E                  ~> inf2E
  2089     join1_iff               ~> sup1_iff
  2090     join2_iff               ~> sup2_iff
  2091     join1I1                 ~> sup1I1
  2092     join2I1                 ~> sup2I1
  2093     join1I1                 ~> sup1I1
  2094     join2I2                 ~> sup1I2
  2095     join1CI                 ~> sup1CI
  2096     join2CI                 ~> sup2CI
  2097     join1E                  ~> sup1E
  2098     join2E                  ~> sup2E
  2099 
  2100     is_meet_Meet            ~> is_meet_Inf
  2101     Meet_bool_def           ~> Inf_bool_def
  2102     Meet_fun_def            ~> Inf_fun_def
  2103     Meet_greatest           ~> Inf_greatest
  2104     Meet_lower              ~> Inf_lower
  2105     Meet_set_def            ~> Inf_set_def
  2106 
  2107     Sup_def                 ~> Sup_Inf
  2108     Sup_bool_eq             ~> Sup_bool_def
  2109     Sup_fun_eq              ~> Sup_fun_def
  2110     Sup_set_eq              ~> Sup_set_def
  2111 
  2112     listsp_meetI            ~> listsp_infI
  2113     listsp_meet_eq          ~> listsp_inf_eq
  2114 
  2115     meet_min                ~> inf_min
  2116     join_max                ~> sup_max
  2117 
  2118 * Added syntactic class "size"; overloaded constant "size" now has
  2119 type "'a::size ==> bool"
  2120 
  2121 * Internal reorganisation of `size' of datatypes: size theorems
  2122 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2123 simplification rules by default!); theorems "prod.size" now named
  2124 "*.size".
  2125 
  2126 * Class "div" now inherits from class "times" rather than "type".
  2127 INCOMPATIBILITY.
  2128 
  2129 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2130 Linorder etc.  have disappeared; operations defined in terms of
  2131 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2132 
  2133 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2134 
  2135 * HOL-Word: New extensive library and type for generic, fixed size
  2136 machine words, with arithemtic, bit-wise, shifting and rotating
  2137 operations, reflection into int, nat, and bool lists, automation for
  2138 linear arithmetic (by automatic reflection into nat or int), including
  2139 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2140 arithmetic type classes, supporting automatic simplification of
  2141 numerals on all operations.
  2142 
  2143 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2144 
  2145 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2146 
  2147 * Code generator library theories:
  2148   - Code_Integer represents HOL integers by big integer literals in target
  2149     languages.
  2150   - Code_Char represents HOL characters by character literals in target
  2151     languages.
  2152   - Code_Char_chr like Code_Char, but also offers treatment of character
  2153     codes; includes Code_Integer.
  2154   - Executable_Set allows to generate code for finite sets using lists.
  2155   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2156     denominator).
  2157   - Executable_Real implements a subset of real numbers, namly those
  2158     representable by rational numbers.
  2159   - Efficient_Nat implements natural numbers by integers, which in general will
  2160     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2161     includes Code_Integer.
  2162   - Code_Index provides an additional datatype index which is mapped to
  2163     target-language built-in integers.
  2164   - Code_Message provides an additional datatype message_string which is isomorphic to
  2165     strings; messages are mapped to target-language strings.
  2166 
  2167 * New package for inductive predicates
  2168 
  2169   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2170 
  2171     inductive
  2172       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2173       for z_1 :: U_1 and ... and z_n :: U_m
  2174     where
  2175       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2176     | ...
  2177 
  2178   with full support for type-inference, rather than
  2179 
  2180     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2181 
  2182     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2183     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2184 
  2185     inductive "s z_1 ... z_m"
  2186     intros
  2187       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2188       ...
  2189 
  2190   For backward compatibility, there is a wrapper allowing inductive
  2191   sets to be defined with the new package via
  2192 
  2193     inductive_set
  2194       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2195       for z_1 :: U_1 and ... and z_n :: U_m
  2196     where
  2197       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2198     | ...
  2199 
  2200   or
  2201 
  2202     inductive_set
  2203       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2204       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2205       for z_1 :: U_1 and ... and z_n :: U_m
  2206     where
  2207       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2208     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2209     | ...
  2210 
  2211   if the additional syntax "p ..." is required.
  2212 
  2213   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2214   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2215 
  2216   INCOMPATIBILITIES:
  2217 
  2218   - Since declaration and definition of inductive sets or predicates
  2219     is no longer separated, abbreviations involving the newly
  2220     introduced sets or predicates must be specified together with the
  2221     introduction rules after the 'where' keyword (see above), rather
  2222     than before the actual inductive definition.
  2223 
  2224   - The variables in induction and elimination rules are now
  2225     quantified in the order of their occurrence in the introduction
  2226     rules, rather than in alphabetical order. Since this may break
  2227     some proofs, these proofs either have to be repaired, e.g. by
  2228     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2229     statements of the form
  2230 
  2231       case (rule_i a_i_1 ... a_i_{k_i})
  2232 
  2233     or the old order of quantification has to be restored by explicitly adding
  2234     meta-level quantifiers in the introduction rules, i.e.
  2235 
  2236       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2237 
  2238   - The format of the elimination rules is now
  2239 
  2240       p z_1 ... z_m x_1 ... x_n ==>
  2241         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2242         ==> ... ==> P
  2243 
  2244     for predicates and
  2245 
  2246       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2247         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2248         ==> ... ==> P
  2249 
  2250     for sets rather than
  2251 
  2252       x : s z_1 ... z_m ==>
  2253         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2254         ==> ... ==> P
  2255 
  2256     This may require terms in goals to be expanded to n-tuples
  2257     (e.g. using case_tac or simplification with the split_paired_all
  2258     rule) before the above elimination rule is applicable.
  2259 
  2260   - The elimination or case analysis rules for (mutually) inductive
  2261     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2262     list of rules "p_1_..._p_k.elims" is no longer available.
  2263 
  2264 * New package "function"/"fun" for general recursive functions,
  2265 supporting mutual and nested recursion, definitions in local contexts,
  2266 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2267 for small examples, and the separate tutorial on the function
  2268 package. The old recdef "package" is still available as before, but
  2269 users are encouraged to use the new package.
  2270 
  2271 * Method "lexicographic_order" automatically synthesizes termination
  2272 relations as lexicographic combinations of size measures. 
  2273 
  2274 * Case-expressions allow arbitrary constructor-patterns (including
  2275 "_") and take their order into account, like in functional
  2276 programming.  Internally, this is translated into nested
  2277 case-expressions; missing cases are added and mapped to the predefined
  2278 constant "undefined". In complicated cases printing may no longer show
  2279 the original input but the internal form. Lambda-abstractions allow
  2280 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2281 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2282 variable.
  2283 
  2284 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2285 is an abbreviation for "of_nat :: nat => int". The simplification
  2286 rules for "of_nat" have been changed to work like "int" did
  2287 previously.  Potential INCOMPATIBILITY:
  2288   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2289   - of_nat_diff and of_nat_mult are no longer default simp rules
  2290 
  2291 * Method "algebra" solves polynomial equations over (semi)rings using
  2292 Groebner bases. The (semi)ring structure is defined by locales and the
  2293 tool setup depends on that generic context. Installing the method for
  2294 a specific type involves instantiating the locale and possibly adding
  2295 declarations for computation on the coefficients.  The method is
  2296 already instantiated for natural numbers and for the axiomatic class
  2297 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2298 CALCULEMUS 2007 for the general principles underlying this
  2299 architecture of context-aware proof-tools.
  2300 
  2301 * Method "ferrack" implements quantifier elimination over
  2302 special-purpose dense linear orders using locales (analogous to
  2303 "algebra"). The method is already installed for class
  2304 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2305 rat, etc.
  2306 
  2307 * Former constant "List.op @" now named "List.append".  Use ML
  2308 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2309 circumvent possible incompatibilities when working on ML level.
  2310 
  2311 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2312 
  2313 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2314 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2315 
  2316 * New syntax for Haskell-like list comprehension (input only), eg.
  2317 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2318 
  2319 * The special syntax for function "filter" has changed from [x :
  2320 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2321 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2322 
  2323 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2324 defined on nat only, as an abbreviation for [a..<Suc b]
  2325 INCOMPATIBILITY.
  2326 
  2327 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2328 
  2329 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2330 
  2331 * New lemma collection field_simps (an extension of ring_simps) for
  2332 manipulating (in)equations involving division. Multiplies with all
  2333 denominators that can be proved to be non-zero (in equations) or
  2334 positive/negative (in inequations).
  2335 
  2336 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2337 have been improved and renamed to ring_simps, group_simps and
  2338 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2339 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2340 
  2341 * Theory Library/Commutative_Ring: switched from recdef to function
  2342 package; constants add, mul, pow now curried.  Infix syntax for
  2343 algebraic operations.
  2344 
  2345 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2346 INCOMPATIBILITY.
  2347 
  2348 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2349 INCOMPATIBILITY.
  2350 
  2351 * HOL/records: generalised field-update to take a function on the
  2352 field rather than the new value: r(|A := x|) is translated to A_update
  2353 (K x) r The K-combinator that is internally used is called K_record.
  2354 INCOMPATIBILITY: Usage of the plain update functions has to be
  2355 adapted.
  2356  
  2357 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2358 * x = 0, which are required for a semiring.  Richer structures do not
  2359 inherit from semiring_0 anymore, because this property is a theorem
  2360 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2361 there is more to prove, but this is mostly trivial.
  2362 
  2363 * Class "recpower" is generalized to arbitrary monoids, not just
  2364 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2365 commutativity or semiring properties additionally.
  2366 
  2367 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2368 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2369 better use 'abbreviation'.
  2370 
  2371 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2372 
  2373 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2374 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2375 significant changes for setting up numeral syntax for types:
  2376   - New constants Numeral.pred and Numeral.succ instead
  2377       of former Numeral.bin_pred and Numeral.bin_succ.
  2378   - Use integer operations instead of bin_add, bin_mult and so on.
  2379   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2380   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2381 
  2382 See src/HOL/Integ/IntArith.thy for an example setup.
  2383 
  2384 * Command 'normal_form' computes the normal form of a term that may
  2385 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2386 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2387 heavy-duty computations because the functions are compiled to ML
  2388 first.  Correspondingly, a method "normalization" is provided.  See
  2389 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2390 
  2391 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2392 25 like -->); output depends on the "iff" print_mode, the default is
  2393 "A = B" (with priority 50).
  2394 
  2395 * Relations less (<) and less_eq (<=) are also available on type bool.
  2396 Modified syntax to disallow nesting without explicit parentheses,
  2397 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2398 INCOMPATIBILITY.
  2399 
  2400 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2401 
  2402 * Relation composition operator "op O" now has precedence 75 and binds
  2403 stronger than union and intersection. INCOMPATIBILITY.
  2404 
  2405 * The old set interval syntax "{m..n(}" (and relatives) has been
  2406 removed.  Use "{m..<n}" (and relatives) instead.
  2407 
  2408 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2409 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2410 ``declare [[simproc del: neq]]''.
  2411 
  2412 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2413 True/False.
  2414 
  2415 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2416 
  2417 * Theorem setsum_mult renamed to setsum_right_distrib.
  2418 
  2419 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2420 ``rule'' method.
  2421 
  2422 * Reimplemented methods "sat" and "satx", with several improvements:
  2423 goals no longer need to be stated as "<prems> ==> False", equivalences
  2424 (i.e. "=" on type bool) are handled, variable names of the form
  2425 "lit_<n>" are no longer reserved, significant speedup.
  2426 
  2427 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2428 zChaff is still supported as well.
  2429 
  2430 * 'inductive' and 'datatype': provide projections of mutual rules,
  2431 bundled as foo_bar.inducts;
  2432 
  2433 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2434 Library.
  2435 
  2436 * Library: moved theory Accessible_Part to main HOL.
  2437 
  2438 * Library: added theory Coinductive_List of potentially infinite lists
  2439 as greatest fixed-point.
  2440 
  2441 * Library: added theory AssocList which implements (finite) maps as
  2442 association lists.
  2443 
  2444 * Method "evaluation" solves goals (i.e. a boolean expression)
  2445 efficiently by compiling it to ML.  The goal is "proved" (via an
  2446 oracle) if it evaluates to True.
  2447 
  2448 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2449 also when invoked by the simplifier.  This results in the Simplifier
  2450 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2451 Configuration option fast_arith_split_limit=0 recovers the old
  2452 behavior.
  2453 
  2454 * Support for hex (0x20) and binary (0b1001) numerals.
  2455 
  2456 * New method: reify eqs (t), where eqs are equations for an
  2457 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2458 parameter, computes a term s::'b and a list xs::'a list and proves the
  2459 theorem I xs s = t. This is also known as reification or quoting. The
  2460 resulting theorem is applied to the subgoal to substitute t with I xs
  2461 s.  If t is omitted, the subgoal itself is reified.
  2462 
  2463 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2464 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2465 where f is supposed to be a computable function (in the sense of code
  2466 generattion). The method uses reify to compute s and xs as above then
  2467 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2468 r and finally gets the theorem t = r, which is again applied to the
  2469 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2470 
  2471 * Reflection: Automatic reification now handels binding, an example is
  2472 available in src/HOL/ex/ReflectionEx.thy
  2473 
  2474 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2475 command 'statespace' that is similar to 'record', but introduces an
  2476 abstract specification based on the locale infrastructure instead of
  2477 HOL types.  This leads to extra flexibility in composing state spaces,
  2478 in particular multiple inheritance and renaming of components.
  2479 
  2480 
  2481 *** HOL-Complex ***
  2482 
  2483 * Hyperreal: Functions root and sqrt are now defined on negative real
  2484 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2485 Nonnegativity side conditions have been removed from many lemmas, so
  2486 that more subgoals may now be solved by simplification; potential
  2487 INCOMPATIBILITY.
  2488 
  2489 * Real: new type classes formalize real normed vector spaces and
  2490 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2491 and norm :: 'a => real.
  2492 
  2493 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2494 reals into other types. The overloaded constant Reals :: 'a set is now
  2495 defined as range of_real; potential INCOMPATIBILITY.
  2496 
  2497 * Real: proper support for ML code generation, including 'quickcheck'.
  2498 Reals are implemented as arbitrary precision rationals.
  2499 
  2500 * Hyperreal: Several constants that previously worked only for the
  2501 reals have been generalized, so they now work over arbitrary vector
  2502 spaces. Type annotations may need to be added in some cases; potential
  2503 INCOMPATIBILITY.
  2504 
  2505   Infinitesimal  :: ('a::real_normed_vector) star set
  2506   HFinite        :: ('a::real_normed_vector) star set
  2507   HInfinite      :: ('a::real_normed_vector) star set
  2508   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2509   monad          :: ('a::real_normed_vector) star => 'a star set
  2510   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2511   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2512   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2513   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2514   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2515   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2516   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2517   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2518   sgn            :: 'a::real_normed_vector => 'a
  2519   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2520 
  2521 * Complex: Some complex-specific constants are now abbreviations for
  2522 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2523 hnorm.  Other constants have been entirely removed in favor of the
  2524 polymorphic versions (INCOMPATIBILITY):
  2525 
  2526   approx        <-- capprox
  2527   HFinite       <-- CFinite
  2528   HInfinite     <-- CInfinite
  2529   Infinitesimal <-- CInfinitesimal
  2530   monad         <-- cmonad
  2531   galaxy        <-- cgalaxy
  2532   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2533   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2534   (ns)deriv     <-- (ns)cderiv
  2535 
  2536 
  2537 *** HOL-Algebra ***
  2538 
  2539 * Formalisation of ideals and the quotient construction over rings.
  2540 
  2541 * Order and lattice theory no longer based on records.
  2542 INCOMPATIBILITY.
  2543 
  2544 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2545 greatest_closed.  INCOMPATIBILITY.
  2546 
  2547 * Method algebra is now set up via an attribute.  For examples see
  2548 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2549 of algebraic structures.
  2550 
  2551 * Renamed theory CRing to Ring.
  2552 
  2553 
  2554 *** HOL-Nominal ***
  2555 
  2556 * Substantial, yet incomplete support for nominal datatypes (binding
  2557 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2558 src/HOL/Nominal/Examples.  Prospective users should consult
  2559 http://isabelle.in.tum.de/nominal/
  2560 
  2561 
  2562 *** ML ***
  2563 
  2564 * ML basics: just one true type int, which coincides with IntInf.int
  2565 (even on SML/NJ).
  2566 
  2567 * ML within Isar: antiquotations allow to embed statically-checked
  2568 formal entities in the source, referring to the context available at
  2569 compile-time.  For example:
  2570 
  2571 ML {* @{sort "{zero,one}"} *}
  2572 ML {* @{typ "'a => 'b"} *}
  2573 ML {* @{term "%x. x"} *}
  2574 ML {* @{prop "x == y"} *}
  2575 ML {* @{ctyp "'a => 'b"} *}
  2576 ML {* @{cterm "%x. x"} *}
  2577 ML {* @{cprop "x == y"} *}
  2578 ML {* @{thm asm_rl} *}
  2579 ML {* @{thms asm_rl} *}
  2580 ML {* @{type_name c} *}
  2581 ML {* @{type_syntax c} *}
  2582 ML {* @{const_name c} *}
  2583 ML {* @{const_syntax c} *}
  2584 ML {* @{context} *}
  2585 ML {* @{theory} *}
  2586 ML {* @{theory Pure} *}
  2587 ML {* @{theory_ref} *}
  2588 ML {* @{theory_ref Pure} *}
  2589 ML {* @{simpset} *}
  2590 ML {* @{claset} *}
  2591 ML {* @{clasimpset} *}
  2592 
  2593 The same works for sources being ``used'' within an Isar context.
  2594 
  2595 * ML in Isar: improved error reporting; extra verbosity with
  2596 ML_Context.trace enabled.
  2597 
  2598 * Pure/General/table.ML: the join operations now works via exceptions
  2599 DUP/SAME instead of type option. This is simpler in simple cases, and
  2600 admits slightly more efficient complex applications.
  2601 
  2602 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2603 use Context.generic instead of just theory.
  2604 
  2605 * Pure: datatype Context.generic joins theory/Proof.context and
  2606 provides some facilities for code that works in either kind of
  2607 context, notably GenericDataFun for uniform theory and proof data.
  2608 
  2609 * Pure: simplified internal attribute type, which is now always
  2610 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2611 local (Proof.context) attributes have been discontinued, while
  2612 minimizing code duplication. Thm.rule_attribute and
  2613 Thm.declaration_attribute build canonical attributes; see also structure
  2614 Context for further operations on Context.generic, notably
  2615 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2616 declarations and definitions.
  2617 
  2618 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2619 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2620 init only required for impure data. INCOMPATIBILITY: empty really need
  2621 to be empty (no dependencies on theory content!)
  2622 
  2623 * Pure/kernel: consts certification ignores sort constraints given in
  2624 signature declarations. (This information is not relevant to the
  2625 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2626 potential INCOMPATIBILITY.
  2627 
  2628 * Pure: axiomatic type classes are now purely definitional, with
  2629 explicit proofs of class axioms and super class relations performed
  2630 internally. See Pure/axclass.ML for the main internal interfaces --
  2631 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2632 AxClass.axiomatize_class/classrel/arity supersede
  2633 Sign.add_classes/classrel/arities.
  2634 
  2635 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2636 global/local versions on theory vs. Proof.context have been
  2637 discontinued; Attrib.syntax and Method.syntax have been adapted
  2638 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2639 attributes, methods, etc.
  2640 
  2641 * Pure: several functions of signature "... -> theory -> theory * ..."
  2642 have been reoriented to "... -> theory -> ... * theory" in order to
  2643 allow natural usage in combination with the ||>, ||>>, |-> and
  2644 fold_map combinators.
  2645 
  2646 * Pure: official theorem names (closed derivations) and additional
  2647 comments (tags) are now strictly separate.  Name hints -- which are
  2648 maintained as tags -- may be attached any time without affecting the
  2649 derivation.
  2650 
  2651 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2652 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2653 achieve the old behaviour.
  2654 
  2655 * Pure: the "Goal" constant is now called "prop", supporting a
  2656 slightly more general idea of ``protecting'' meta-level rule
  2657 statements.
  2658 
  2659 * Pure: Logic.(un)varify only works in a global context, which is now
  2660 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2661 Logic.legacy_(un)varify as temporary workaround.
  2662 
  2663 * Pure: structure Name provides scalable operations for generating
  2664 internal variable names, notably Name.variants etc.  This replaces
  2665 some popular functions from term.ML:
  2666 
  2667   Term.variant		->  Name.variant
  2668   Term.variantlist	->  Name.variant_list
  2669   Term.invent_names	->  Name.invent_list
  2670 
  2671 Note that low-level renaming rarely occurs in new code -- operations
  2672 from structure Variable are used instead (see below).
  2673 
  2674 * Pure: structure Variable provides fundamental operations for proper
  2675 treatment of fixed/schematic variables in a context.  For example,
  2676 Variable.import introduces fixes for schematics of given facts and
  2677 Variable.export reverses the effect (up to renaming) -- this replaces
  2678 various freeze_thaw operations.
  2679 
  2680 * Pure: structure Goal provides simple interfaces for
  2681 init/conclude/finish and tactical prove operations (replacing former
  2682 Tactic.prove).  Goal.prove is the canonical way to prove results
  2683 within a given context; Goal.prove_global is a degraded version for
  2684 theory level goals, including a global Drule.standard.  Note that
  2685 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2686 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2687 in a locale context).
  2688 
  2689 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2690 and type checking (Syntax.check_term etc.), with common combinations
  2691 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2692 which are considered legacy and await removal.
  2693 
  2694 * Pure/Syntax: generic interfaces for type unchecking
  2695 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2696 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2697 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2698 available for convenience, but refer to the very same operations using
  2699 a mere theory instead of a full context.
  2700 
  2701 * Isar: simplified treatment of user-level errors, using exception
  2702 ERROR of string uniformly.  Function error now merely raises ERROR,
  2703 without any side effect on output channels.  The Isar toplevel takes
  2704 care of proper display of ERROR exceptions.  ML code may use plain
  2705 handle/can/try; cat_error may be used to concatenate errors like this:
  2706 
  2707   ... handle ERROR msg => cat_error msg "..."
  2708 
  2709 Toplevel ML code (run directly or through the Isar toplevel) may be
  2710 embedded into the Isar toplevel with exception display/debug like
  2711 this:
  2712 
  2713   Isar.toplevel (fn () => ...)
  2714 
  2715 INCOMPATIBILITY, removed special transform_error facilities, removed
  2716 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2717 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2718 -- use plain ERROR instead.
  2719 
  2720 * Isar: theory setup now has type (theory -> theory), instead of a
  2721 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2722 
  2723 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2724 ProofContext.debug/verbose flags.
  2725 
  2726 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2727 theory before entering a proof state.  Transactions now always see a
  2728 quasi-functional intermediate checkpoint, both in interactive and
  2729 batch mode.
  2730 
  2731 * Isar: simplified interfaces for outer syntax.  Renamed
  2732 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2733 OuterSyntax.add_parsers -- this functionality is now included in
  2734 OuterSyntax.command etc.  INCOMPATIBILITY.
  2735 
  2736 * Simplifier: the simpset of a running simplification process now
  2737 contains a proof context (cf. Simplifier.the_context), which is the
  2738 very context that the initial simpset has been retrieved from (by
  2739 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2740 (solver, looper etc.) may depend on arbitrary proof data.
  2741 
  2742 * Simplifier.inherit_context inherits the proof context (plus the
  2743 local bounds) of the current simplification process; any simproc
  2744 etc. that calls the Simplifier recursively should do this!  Removed
  2745 former Simplifier.inherit_bounds, which is already included here --
  2746 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2747 specify an explicit context using Simplifier.context/theory_context.
  2748 
  2749 * Simplifier/Classical Reasoner: more abstract interfaces
  2750 change_simpset/claset for modifying the simpset/claset reference of a
  2751 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2752 INCOMPATIBILITY.
  2753 
  2754 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2755 "Trueprop" etc.
  2756 
  2757 
  2758 *** System ***
  2759 
  2760 * settings: the default heap location within ISABELLE_HOME_USER now
  2761 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2762 Isabelle installations.
  2763 
  2764 * isabelle-process: option -S (secure mode) disables some critical
  2765 operations, notably runtime compilation and evaluation of ML source
  2766 code.
  2767 
  2768 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2769 
  2770 * Support for parallel execution, using native multicore support of
  2771 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2772 independent theories, according to the given theory header
  2773 specifications. The maximum number of worker threads is specified via
  2774 usedir option -M or the "max-threads" setting in Proof General. A
  2775 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2776 to 6 on a 8-core machine.  User-code needs to observe certain
  2777 guidelines for thread-safe programming, see appendix A in the Isar
  2778 Implementation manual.
  2779 
  2780 
  2781 
  2782 New in Isabelle2005 (October 2005)
  2783 ----------------------------------
  2784 
  2785 *** General ***
  2786 
  2787 * Theory headers: the new header syntax for Isar theories is
  2788 
  2789   theory <name>
  2790   imports <theory1> ... <theoryN>
  2791   uses <file1> ... <fileM>
  2792   begin
  2793 
  2794 where the 'uses' part is optional.  The previous syntax
  2795 
  2796   theory <name> = <theory1> + ... + <theoryN>:
  2797 
  2798 will disappear in the next release.  Use isatool fixheaders to convert
  2799 existing theory files.  Note that there is no change in ancient
  2800 non-Isar theories now, but these will disappear soon.
  2801 
  2802 * Theory loader: parent theories can now also be referred to via
  2803 relative and absolute paths.
  2804 
  2805 * Command 'find_theorems' searches for a list of criteria instead of a
  2806 list of constants. Known criteria are: intro, elim, dest, name:string,
  2807 simp:term, and any term. Criteria can be preceded by '-' to select
  2808 theorems that do not match. Intro, elim, dest select theorems that
  2809 match the current goal, name:s selects theorems whose fully qualified
  2810 name contain s, and simp:term selects all simplification rules whose
  2811 lhs match term.  Any other term is interpreted as pattern and selects
  2812 all theorems matching the pattern. Available in ProofGeneral under
  2813 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2814 
  2815   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2816 
  2817 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2818 matching the current goal as introduction rule and not having "HOL."
  2819 in their name (i.e. not being defined in theory HOL).
  2820 
  2821 * Command 'thms_containing' has been discontinued in favour of
  2822 'find_theorems'; INCOMPATIBILITY.
  2823 
  2824 * Communication with Proof General is now 8bit clean, which means that
  2825 Unicode text in UTF-8 encoding may be used within theory texts (both
  2826 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2827 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2828 
  2829   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2830   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2831 
  2832 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2833 Classical Reasoner.  Typical big applications run around 2 times
  2834 faster.
  2835 
  2836 
  2837 *** Document preparation ***
  2838 
  2839 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2840 of raw sources.  Only those symbols that do not require additional
  2841 LaTeX packages (depending on comments in isabellesym.sty) are
  2842 displayed properly, everything else is left verbatim.  isatool display
  2843 and isatool print are used as front ends (these are subject to the
  2844 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2845 
  2846 * Command tags control specific markup of certain regions of text,
  2847 notably folding and hiding.  Predefined tags include "theory" (for
  2848 theory begin and end), "proof" for proof commands, and "ML" for
  2849 commands involving ML code; the additional tags "visible" and
  2850 "invisible" are unused by default.  Users may give explicit tag
  2851 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2852 interpretation of tags is determined by the LaTeX job during document
  2853 preparation: see option -V of isatool usedir, or options -n and -t of
  2854 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2855 \isadroptag.
  2856 
  2857 Several document versions may be produced at the same time via isatool
  2858 usedir (the generated index.html will link all of them).  Typical
  2859 specifications include ''-V document=theory,proof,ML'' to present
  2860 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2861 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2862 these parts without any formal replacement text.  The Isabelle site
  2863 default settings produce ''document'' and ''outline'' versions as
  2864 specified above.
  2865 
  2866 * Several new antiquotations:
  2867 
  2868   @{term_type term} prints a term with its type annotated;
  2869 
  2870   @{typeof term} prints the type of a term;
  2871 
  2872   @{const const} is the same as @{term const}, but checks that the
  2873   argument is a known logical constant;
  2874 
  2875   @{term_style style term} and @{thm_style style thm} print a term or
  2876   theorem applying a "style" to it
  2877 
  2878   @{ML text}
  2879 
  2880 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2881 definitions, equations, inequations etc., 'concl' printing only the
  2882 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2883 to print the specified premise.  TermStyle.add_style provides an ML
  2884 interface for introducing further styles.  See also the "LaTeX Sugar"
  2885 document practical applications.  The ML antiquotation prints
  2886 type-checked ML expressions verbatim.
  2887 
  2888 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2889 and 'text' support optional locale specification '(in loc)', which
  2890 specifies the default context for interpreting antiquotations.  For
  2891 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2892 
  2893 * Option 'locale=NAME' of antiquotations specifies an alternative
  2894 context interpreting the subsequent argument.  For example: @{thm
  2895 [locale=lattice] inf_assoc}.
  2896 
  2897 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2898 a proof context.
  2899 
  2900 * Proper output of antiquotations for theory commands involving a
  2901 proof context (such as 'locale' or 'theorem (in loc) ...').
  2902 
  2903 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2904 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2905 
  2906 * isatool usedir: new option -C (default true) controls whether option
  2907 -D should include a copy of the original document directory; -C false
  2908 prevents unwanted effects such as copying of administrative CVS data.
  2909 
  2910 
  2911 *** Pure ***
  2912 
  2913 * Considerably improved version of 'constdefs' command.  Now performs
  2914 automatic type-inference of declared constants; additional support for
  2915 local structure declarations (cf. locales and HOL records), see also
  2916 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2917 sequential dependencies of definitions within a single 'constdefs'
  2918 section; moreover, the declared name needs to be an identifier.  If
  2919 all fails, consider to fall back on 'consts' and 'defs' separately.
  2920 
  2921 * Improved indexed syntax and implicit structures.  First of all,
  2922 indexed syntax provides a notational device for subscripted
  2923 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2924 expressions.  Secondly, in a local context with structure
  2925 declarations, number indexes \<^sub>n or the empty index (default
  2926 number 1) refer to a certain fixed variable implicitly; option
  2927 show_structs controls printing of implicit structures.  Typical
  2928 applications of these concepts involve record types and locales.
  2929 
  2930 * New command 'no_syntax' removes grammar declarations (and
  2931 translations) resulting from the given syntax specification, which is
  2932 interpreted in the same manner as for the 'syntax' command.
  2933 
  2934 * 'Advanced' translation functions (parse_translation etc.) may depend
  2935 on the signature of the theory context being presently used for
  2936 parsing/printing, see also isar-ref manual.
  2937 
  2938 * Improved 'oracle' command provides a type-safe interface to turn an
  2939 ML expression of type theory -> T -> term into a primitive rule of
  2940 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2941 is already included here); see also FOL/ex/IffExample.thy;
  2942 INCOMPATIBILITY.
  2943 
  2944 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2945 before); "cI" is no longer bound, use "c.intro" instead.
  2946 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2947 axclasses vs. locales.
  2948 
  2949 * Improved internal renaming of symbolic identifiers -- attach primes
  2950 instead of base 26 numbers.
  2951 
  2952 * New flag show_question_marks controls printing of leading question
  2953 marks in schematic variable names.
  2954 
  2955 * In schematic variable names, *any* symbol following \<^isub> or
  2956 \<^isup> is now treated as part of the base name.  For example, the
  2957 following works without printing of awkward ".0" indexes:
  2958 
  2959   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2960     by simp
  2961 
  2962 * Inner syntax includes (*(*nested*) comments*).
  2963 
  2964 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2965 annotations as "(00...)".
  2966 
  2967 * Clear separation of logical types and nonterminals, where the latter
  2968 may only occur in 'syntax' specifications or type abbreviations.
  2969 Before that distinction was only partially implemented via type class
  2970 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2971 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2972 exotic syntax specifications may require further adaption
  2973 (e.g. Cube/Cube.thy).
  2974 
  2975 * Removed obsolete type class "logic", use the top sort {} instead.
  2976 Note that non-logical types should be declared as 'nonterminals'
  2977 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2978 specifications.
  2979 
  2980 * Attributes 'induct' and 'cases': type or set names may now be
  2981 locally fixed variables as well.
  2982 
  2983 * Simplifier: can now control the depth to which conditional rewriting
  2984 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2985 Limit.
  2986 
  2987 * Simplifier: simplification procedures may now take the current
  2988 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2989 interface), which is very useful for calling the Simplifier
  2990 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2991 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2992 low-level mk_simproc no longer applies Logic.varify internally, to
  2993 allow for use in a context of fixed variables.
  2994 
  2995 * thin_tac now works even if the assumption being deleted contains !!
  2996 or ==>.  More generally, erule now works even if the major premise of
  2997 the elimination rule contains !! or ==>.
  2998 
  2999 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  3000 
  3001 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  3002 from Pure, which contains all common declarations already.  Both
  3003 theories are defined via plain Isabelle/Isar .thy files.
  3004 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  3005 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  3006 use isatool fixcpure to adapt your theory and ML sources.
  3007 
  3008 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  3009 selections of theorems in named facts via index ranges.
  3010 
  3011 * 'print_theorems': in theory mode, really print the difference
  3012 wrt. the last state (works for interactive theory development only),
  3013 in proof mode print all local facts (cf. 'print_facts');
  3014 
  3015 * 'hide': option '(open)' hides only base names.
  3016 
  3017 * More efficient treatment of intermediate checkpoints in interactive
  3018 theory development.
  3019 
  3020 * Code generator is now invoked via code_module (incremental code
  3021 generation) and code_library (modular code generation, ML structures
  3022 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  3023 must be quoted when used as identifiers.
  3024 
  3025 * New 'value' command for reading, evaluating and printing terms using
  3026 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  3027 quoted when used as identifier.
  3028 
  3029 
  3030 *** Locales ***
  3031 
  3032 * New commands for the interpretation of locale expressions in
  3033 theories (1), locales (2) and proof contexts (3).  These generate
  3034 proof obligations from the expression specification.  After the
  3035 obligations have been discharged, theorems of the expression are added
  3036 to the theory, target locale or proof context.  The synopsis of the
  3037 commands is a follows:
  3038 
  3039   (1) interpretation expr inst
  3040   (2) interpretation target < expr
  3041   (3) interpret expr inst
  3042 
  3043 Interpretation in theories and proof contexts require a parameter
  3044 instantiation of terms from the current context.  This is applied to
  3045 specifications and theorems of the interpreted expression.
  3046 Interpretation in locales only permits parameter renaming through the
  3047 locale expression.  Interpretation is smart in that interpretations
  3048 that are active already do not occur in proof obligations, neither are
  3049 instantiated theorems stored in duplicate.  Use 'print_interps' to
  3050 inspect active interpretations of a particular locale.  For details,
  3051 see the Isar Reference manual.  Examples can be found in
  3052 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  3053 
  3054 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  3055 'interpret' instead.
  3056 
  3057 * New context element 'constrains' for adding type constraints to
  3058 parameters.
  3059 
  3060 * Context expressions: renaming of parameters with syntax
  3061 redeclaration.
  3062 
  3063 * Locale declaration: 'includes' disallowed.
  3064 
  3065 * Proper static binding of attribute syntax -- i.e. types / terms /
  3066 facts mentioned as arguments are always those of the locale definition
  3067 context, independently of the context of later invocations.  Moreover,
  3068 locale operations (renaming and type / term instantiation) are applied
  3069 to attribute arguments as expected.
  3070 
  3071 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  3072 actual attributes; rare situations may require Attrib.attribute to
  3073 embed those attributes into Attrib.src that lack concrete syntax.
  3074 Attribute implementations need to cooperate properly with the static
  3075 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  3076 Attrib.XXX_thm etc. already do the right thing without further
  3077 intervention.  Only unusual applications -- such as "where" or "of"
  3078 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  3079 on the context and the facts involved -- may have to assign parsed
  3080 values to argument tokens explicitly.
  3081 
  3082 * Changed parameter management in theorem generation for long goal
  3083 statements with 'includes'.  INCOMPATIBILITY: produces a different
  3084 theorem statement in rare situations.
  3085 
  3086 * Locale inspection command 'print_locale' omits notes elements.  Use
  3087 'print_locale!' to have them included in the output.
  3088 
  3089 
  3090 *** Provers ***
  3091 
  3092 * Provers/hypsubst.ML: improved version of the subst method, for
  3093 single-step rewriting: it now works in bound variable contexts. New is
  3094 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  3095 rewrite a different subterm than the original subst method, which is
  3096 still available as 'simplesubst'.
  3097 
  3098 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  3099 and quasi orders.
  3100 
  3101 * Provers/trancl.ML: new transitivity reasoner for transitive and
  3102 reflexive-transitive closure of relations.
  3103 
  3104 * Provers/blast.ML: new reference depth_limit to make blast's depth
  3105 limit (previously hard-coded with a value of 20) user-definable.
  3106 
  3107 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  3108 is peformed already.  Object-logics merely need to finish their
  3109 initial simpset configuration as before.  INCOMPATIBILITY.
  3110 
  3111 
  3112 *** HOL ***
  3113 
  3114 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3115 
  3116   syntax (epsilon)
  3117     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3118 
  3119 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3120 and x-symbol; use option '-m epsilon' to get it actually printed.
  3121 Moreover, the mathematically important symbolic identifier \<epsilon>
  3122 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3123 
  3124 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3125 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3126 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3127 support corresponding Isar calculations.
  3128 
  3129 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3130 instead of ":".
  3131 
  3132 * theory SetInterval: changed the syntax for open intervals:
  3133 
  3134   Old       New
  3135   {..n(}    {..<n}
  3136   {)n..}    {n<..}
  3137   {m..n(}   {m..<n}
  3138   {)m..n}   {m<..n}
  3139   {)m..n(}  {m<..<n}
  3140 
  3141 The old syntax is still supported but will disappear in the next
  3142 release.  For conversion use the following Emacs search and replace
  3143 patterns (these are not perfect but work quite well):
  3144 
  3145   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3146   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3147 
  3148 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3149 equalities in commutative rings; method 'algebra' provides a generic
  3150 interface.
  3151 
  3152 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3153 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3154 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3155 be a tuple pattern.
  3156 
  3157 Some new syntax forms are available:
  3158 
  3159   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3160   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3161   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3162   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3163 
  3164 The latter form "\<Sum>x < k. e" used to be based on a separate
  3165 function "Summation", which has been discontinued.
  3166 
  3167 * theory Finite_Set: in structured induction proofs, the insert case
  3168 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3169 (insert F x)'.
  3170 
  3171 * The 'refute' command has been extended to support a much larger
  3172 fragment of HOL, including axiomatic type classes, constdefs and
  3173 typedefs, inductive datatypes and recursion.
  3174 
  3175 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3176 Requires zChaff with proof generation to be installed.  See
  3177 HOL/ex/SAT_Examples.thy for examples.
  3178 
  3179 * Datatype induction via method 'induct' now preserves the name of the
  3180 induction variable. For example, when proving P(xs::'a list) by
  3181 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3182 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3183 in unstructured proof scripts.
  3184 
  3185 * Reworked implementation of records.  Improved scalability for
  3186 records with many fields, avoiding performance problems for type
  3187 inference. Records are no longer composed of nested field types, but
  3188 of nested extension types. Therefore the record type only grows linear
  3189 in the number of extensions and not in the number of fields.  The
  3190 top-level (users) view on records is preserved.  Potential
  3191 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3192 old record representation. The type generated for a record is called
  3193 <record_name>_ext_type.
  3194 
  3195 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3196 proofs triggered by a record definition or a simproc (if
  3197 quick_and_dirty is enabled).  Definitions of large records can take
  3198 quite long.
  3199 
  3200 New simproc record_upd_simproc for simplification of multiple record
  3201 updates enabled by default.  Moreover, trivial updates are also
  3202 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3203 occasionally, since simplification is more powerful by default.
  3204 
  3205 * typedef: proper support for polymorphic sets, which contain extra
  3206 type-variables in the term.
  3207 
  3208 * Simplifier: automatically reasons about transitivity chains
  3209 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3210 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3211 old proofs break occasionally as simplification may now solve more
  3212 goals than previously.
  3213 
  3214 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3215 present.  Works for all partial orders (class "order"), in particular
  3216 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3217 just like y <= x.
  3218 
  3219 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3220 bound variable or a constant then the let is unfolded.  Otherwise
  3221 first a is simplified to b, and then f b is simplified to g. If
  3222 possible we abstract b from g arriving at "let x = b in h x",
  3223 otherwise we unfold the let and arrive at g.  The simproc can be
  3224 enabled/disabled by the reference use_let_simproc.  Potential
  3225 INCOMPATIBILITY since simplification is more powerful by default.
  3226 
  3227 * Classical reasoning: the meson method now accepts theorems as arguments.
  3228 
  3229 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3230 jobs to provide advice on the provability of subgoals.
  3231 
  3232 * Theory OrderedGroup and Ring_and_Field: various additions and
  3233 improvements to faciliate calculations involving equalities and
  3234 inequalities.
  3235 
  3236 The following theorems have been eliminated or modified
  3237 (INCOMPATIBILITY):
  3238 
  3239   abs_eq             now named abs_of_nonneg
  3240   abs_of_ge_0        now named abs_of_nonneg
  3241   abs_minus_eq       now named abs_of_nonpos
  3242   imp_abs_id         now named abs_of_nonneg
  3243   imp_abs_neg_id     now named abs_of_nonpos
  3244   mult_pos           now named mult_pos_pos
  3245   mult_pos_le        now named mult_nonneg_nonneg
  3246   mult_pos_neg_le    now named mult_nonneg_nonpos
  3247   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3248   mult_neg           now named mult_neg_neg
  3249   mult_neg_le        now named mult_nonpos_nonpos
  3250 
  3251 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3252      
  3253      zero_le_square
  3254      not_square_less_zero 
  3255 
  3256   The following lemmas have been deleted from Real/RealPow:
  3257   
  3258      realpow_zero_zero
  3259      realpow_two
  3260      realpow_less
  3261      zero_le_power
  3262      realpow_two_le
  3263      abs_realpow_two
  3264      realpow_two_abs     
  3265 
  3266 * Theory Parity: added rules for simplifying exponents.
  3267 
  3268 * Theory List:
  3269 
  3270 The following theorems have been eliminated or modified
  3271 (INCOMPATIBILITY):
  3272 
  3273   list_all_Nil       now named list_all.simps(1)
  3274   list_all_Cons      now named list_all.simps(2)
  3275   list_all_conv      now named list_all_iff
  3276   set_mem_eq         now named mem_iff
  3277 
  3278 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3279 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3280 
  3281 
  3282 *** HOL-Complex ***
  3283 
  3284 * Theory RealDef: better support for embedding natural numbers and
  3285 integers in the reals.
  3286 
  3287 The following theorems have been eliminated or modified
  3288 (INCOMPATIBILITY):
  3289 
  3290   exp_ge_add_one_self  now requires no hypotheses
  3291   real_of_int_add      reversed direction of equality (use [symmetric])
  3292   real_of_int_minus    reversed direction of equality (use [symmetric])
  3293   real_of_int_diff     reversed direction of equality (use [symmetric])
  3294   real_of_int_mult     reversed direction of equality (use [symmetric])
  3295 
  3296 * Theory RComplete: expanded support for floor and ceiling functions.
  3297 
  3298 * Theory Ln is new, with properties of the natural logarithm
  3299 
  3300 * Hyperreal: There is a new type constructor "star" for making
  3301 nonstandard types.  The old type names are now type synonyms:
  3302 
  3303   hypreal = real star
  3304   hypnat = nat star
  3305   hcomplex = complex star
  3306 
  3307 * Hyperreal: Many groups of similarly-defined constants have been
  3308 replaced by polymorphic versions (INCOMPATIBILITY):
  3309 
  3310   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3311 
  3312   starset      <-- starsetNat, starsetC
  3313   *s*          <-- *sNat*, *sc*
  3314   starset_n    <-- starsetNat_n, starsetC_n
  3315   *sn*         <-- *sNatn*, *scn*
  3316   InternalSets <-- InternalNatSets, InternalCSets
  3317 
  3318   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3319   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3320   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3321   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3322   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3323 
  3324 * Hyperreal: Many type-specific theorems have been removed in favor of
  3325 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3326 
  3327   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3328   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3329   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3330   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3331   right_minus <-- hypreal_add_minus
  3332   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3333   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3334   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3335   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3336   mult_1_right <-- hcomplex_mult_one_right
  3337   mult_zero_left <-- hcomplex_mult_zero_left
  3338   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3339   right_distrib <-- hypnat_add_mult_distrib2
  3340   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3341   right_inverse <-- hypreal_mult_inverse
  3342   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3343   order_refl <-- {hypreal,hypnat}_le_refl
  3344   order_trans <-- {hypreal,hypnat}_le_trans
  3345   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3346   order_less_le <-- {hypreal,hypnat}_less_le
  3347   linorder_linear <-- {hypreal,hypnat}_le_linear
  3348   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3349   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3350   add_nonneg_nonneg <-- hypreal_le_add_order
  3351 
  3352 * Hyperreal: Separate theorems having to do with type-specific
  3353 versions of constants have been merged into theorems that apply to the
  3354 new polymorphic constants (INCOMPATIBILITY):
  3355 
  3356   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3357   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3358   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3359   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3360   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3361   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3362   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3363   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3364   STAR_diff <-- {STAR,STARC}_diff
  3365   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3366     STARC_hcomplex_of_complex}_image_subset
  3367   starset_n_Un <-- starset{Nat,C}_n_Un
  3368   starset_n_Int <-- starset{Nat,C}_n_Int
  3369   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3370   starset_n_diff <-- starset{Nat,C}_n_diff
  3371   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3372   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3373   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3374   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3375   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3376   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3377   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3378   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3379   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3380   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3381   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3382   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3383   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3384   starfun_diff <-- starfun{C,RC,CR}_diff
  3385   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3386   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3387   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3388   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3389   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3390   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3391   starfun_Id <-- starfunC_Id
  3392   starfun_approx <-- starfun{Nat,CR}_approx
  3393   starfun_capprox <-- starfun{C,RC}_capprox
  3394   starfun_abs <-- starfunNat_rabs
  3395   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3396   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3397   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3398   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3399   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3400   starfun_add_approx <-- starfunCR_add_approx
  3401   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3402   starfun_divide <-- starfun{C,CR,RC}_divide
  3403   starfun_n <-- starfun{Nat,C}_n
  3404   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3405   starfun_n_add <-- starfun{Nat,C}_n_add
  3406   starfun_n_add_minus <-- starfunNat_n_add_minus
  3407   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3408   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3409   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3410 
  3411   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3412   star_n_minus <-- {hypreal,hcomplex}_minus
  3413   star_n_diff <-- {hypreal,hcomplex}_diff
  3414   star_n_mult <-- {hypreal,hcomplex}_mult
  3415   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3416   star_n_le <-- {hypreal,hypnat}_le
  3417   star_n_less <-- {hypreal,hypnat}_less
  3418   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3419   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3420   star_n_abs <-- hypreal_hrabs
  3421   star_n_divide <-- hcomplex_divide
  3422 
  3423   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3424   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3425   star_of_diff <-- hypreal_of_real_diff
  3426   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3427   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3428   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3429   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3430   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3431   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3432   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3433   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3434   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3435   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3436   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3437   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3438   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3439   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3440   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3441   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3442   star_of_power <-- hypreal_of_real_power
  3443   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3444 
  3445 * Hyperreal: new method "transfer" that implements the transfer
  3446 principle of nonstandard analysis. With a subgoal that mentions
  3447 nonstandard types like "'a star", the command "apply transfer"
  3448 replaces it with an equivalent one that mentions only standard types.
  3449 To be successful, all free variables must have standard types; non-
  3450 standard variables must have explicit universal quantifiers.
  3451 
  3452 * Hyperreal: A theory of Taylor series.
  3453 
  3454 
  3455 *** HOLCF ***
  3456 
  3457 * Discontinued special version of 'constdefs' (which used to support
  3458 continuous functions) in favor of the general Pure one with full
  3459 type-inference.
  3460 
  3461 * New simplification procedure for solving continuity conditions; it
  3462 is much faster on terms with many nested lambda abstractions (cubic
  3463 instead of exponential time).
  3464 
  3465 * New syntax for domain package: selector names are now optional.
  3466 Parentheses should be omitted unless argument is lazy, for example:
  3467 
  3468   domain 'a stream = cons "'a" (lazy "'a stream")
  3469 
  3470 * New command 'fixrec' for defining recursive functions with pattern
  3471 matching; defining multiple functions with mutual recursion is also
  3472 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3473 sinr, or any data constructor defined by the domain package. The given
  3474 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3475 syntax and examples.
  3476 
  3477 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3478 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3479 but the proof obligation additionally includes an admissibility
  3480 requirement. The packages generate instances of class cpo or pcpo,
  3481 with continuity and strictness theorems for Rep and Abs.
  3482 
  3483 * HOLCF: Many theorems have been renamed according to a more standard naming
  3484 scheme (INCOMPATIBILITY):
  3485 
  3486   foo_inject:  "foo$x = foo$y ==> x = y"
  3487   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3488   foo_less:    "(foo$x << foo$y) = (x << y)"
  3489   foo_strict:  "foo$UU = UU"
  3490   foo_defined: "... ==> foo$x ~= UU"
  3491   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3492 
  3493 
  3494 *** ZF ***
  3495 
  3496 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3497 including the First Isomorphism Theorem (on quotienting by the kernel
  3498 of a homomorphism).
  3499 
  3500 * ZF/Simplifier: install second copy of type solver that actually
  3501 makes use of TC rules declared to Isar proof contexts (or locales);
  3502 the old version is still required for ML proof scripts.
  3503 
  3504 
  3505 *** Cube ***
  3506 
  3507 * Converted to Isar theory format; use locales instead of axiomatic
  3508 theories.
  3509 
  3510 
  3511 *** ML ***
  3512 
  3513 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3514 for ||>, ||>>, |>>,
  3515 
  3516 * Pure/library.ML no longer defines its own option datatype, but uses
  3517 that of the SML basis, which has constructors NONE and SOME instead of
  3518 None and Some, as well as exception Option.Option instead of OPTION.
  3519 The functions the, if_none, is_some, is_none have been adapted
  3520 accordingly, while Option.map replaces apsome.
  3521 
  3522 * Pure/library.ML: the exception LIST has been given up in favour of
  3523 the standard exceptions Empty and Subscript, as well as
  3524 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3525 superceded by the standard hd and tl functions etc.
  3526 
  3527 A number of basic list functions are no longer exported to the ML
  3528 toplevel, as they are variants of predefined functions.  The following
  3529 suggests how one can translate existing code:
  3530 
  3531     rev_append xs ys = List.revAppend (xs, ys)
  3532     nth_elem (i, xs) = List.nth (xs, i)
  3533     last_elem xs = List.last xs
  3534     flat xss = List.concat xss
  3535     seq fs = List.app fs
  3536     partition P xs = List.partition P xs
  3537     mapfilter f xs = List.mapPartial f xs
  3538 
  3539 * Pure/library.ML: several combinators for linear functional
  3540 transformations, notably reverse application and composition:
  3541 
  3542   x |> f                f #> g
  3543   (x, y) |-> f          f #-> g
  3544 
  3545 * Pure/library.ML: introduced/changed precedence of infix operators:
  3546 
  3547   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3548   infix 2 ?;
  3549   infix 3 o oo ooo oooo;
  3550   infix 4 ~~ upto downto;
  3551 
  3552 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3553 infix operators.
  3554 
  3555 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3556 fold_map support linear functional transformations and nesting.  For
  3557 example:
  3558 
  3559   fold f [x1, ..., xN] y =
  3560     y |> f x1 |> ... |> f xN
  3561 
  3562   (fold o fold) f [xs1, ..., xsN] y =
  3563     y |> fold f xs1 |> ... |> fold f xsN
  3564 
  3565   fold f [x1, ..., xN] =
  3566     f x1 #> ... #> f xN
  3567 
  3568   (fold o fold) f [xs1, ..., xsN] =
  3569     fold f xs1 #> ... #> fold f xsN
  3570 
  3571 * Pure/library.ML: the following selectors on type 'a option are
  3572 available:
  3573 
  3574   the:               'a option -> 'a  (*partial*)
  3575   these:             'a option -> 'a  where 'a = 'b list
  3576   the_default: 'a -> 'a option -> 'a
  3577   the_list:          'a option -> 'a list
  3578 
  3579 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3580 basic operations for association lists, following natural argument
  3581 order; moreover the explicit equality predicate passed here avoids
  3582 potentially expensive polymorphic runtime equality checks.
  3583 The old functions may be expressed as follows:
  3584 
  3585   assoc = uncurry (AList.lookup (op =))
  3586   assocs = these oo AList.lookup (op =)
  3587   overwrite = uncurry (AList.update (op =)) o swap
  3588 
  3589 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3590 
  3591   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3592   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3593 
  3594 replacing make_keylist and keyfilter (occassionally used)
  3595 Naive rewrites:
  3596 
  3597   make_keylist = AList.make
  3598   keyfilter = AList.find (op =)
  3599 
  3600 * eq_fst and eq_snd now take explicit equality parameter, thus
  3601   avoiding eqtypes. Naive rewrites:
  3602 
  3603     eq_fst = eq_fst (op =)
  3604     eq_snd = eq_snd (op =)
  3605 
  3606 * Removed deprecated apl and apr (rarely used).
  3607   Naive rewrites:
  3608 
  3609     apl (n, op) =>>= curry op n
  3610     apr (op, m) =>>= fn n => op (n, m)
  3611 
  3612 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3613 provides a reasonably efficient light-weight implementation of sets as
  3614 lists.
  3615 
  3616 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3617 few new operations; existing lookup and update are now curried to
  3618 follow natural argument order (for use with fold etc.);
  3619 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3620 
  3621 * Pure/General: output via the Isabelle channels of
  3622 writeln/warning/error etc. is now passed through Output.output, with a
  3623 hook for arbitrary transformations depending on the print_mode
  3624 (cf. Output.add_mode -- the first active mode that provides a output
  3625 function wins).  Already formatted output may be embedded into further
  3626 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3627 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3628 accommodate easy composition of diagnostic messages etc.  Programmers
  3629 rarely need to care about Output.output or Output.raw at all, with
  3630 some notable exceptions: Output.output is required when bypassing the
  3631 standard channels (writeln etc.), or in token translations to produce
  3632 properly formatted results; Output.raw is required when capturing
  3633 already output material that will eventually be presented to the user
  3634 a second time.  For the default print mode, both Output.output and
  3635 Output.raw have no effect.
  3636 
  3637 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3638 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3639 cumulative results are displayed at the end of a batch session.
  3640 
  3641 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3642 replaced by File.platform_path and File.shell_path (with appropriate
  3643 hooks).  This provides a clean interface for unusual systems where the
  3644 internal and external process view of file names are different.
  3645 
  3646 * Pure: more efficient orders for basic syntactic entities: added
  3647 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3648 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3649 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3650 orders now -- potential INCOMPATIBILITY for code that depends on a
  3651 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3652 Library.sort_strings on result).
  3653 
  3654 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3655 fold_types traverse types/terms from left to right, observing natural
  3656 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3657 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3658 
  3659 * Pure: name spaces have been refined, with significant changes of the
  3660 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3661 to extern(_table).  The plain name entry path is superceded by a
  3662 general 'naming' context, which also includes the 'policy' to produce
  3663 a fully qualified name and external accesses of a fully qualified
  3664 name; NameSpace.extend is superceded by context dependent
  3665 Sign.declare_name.  Several theory and proof context operations modify
  3666 the naming context.  Especially note Theory.restore_naming and
  3667 ProofContext.restore_naming to get back to a sane state; note that
  3668 Theory.add_path is no longer sufficient to recover from
  3669 Theory.absolute_path in particular.
  3670 
  3671 * Pure: new flags short_names (default false) and unique_names
  3672 (default true) for controlling output of qualified names.  If
  3673 short_names is set, names are printed unqualified.  If unique_names is
  3674 reset, the name prefix is reduced to the minimum required to achieve
  3675 the original result when interning again, even if there is an overlap
  3676 with earlier declarations.
  3677 
  3678 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3679 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3680 (useful for printing error messages).  INCOMPATIBILITY.
  3681 
  3682 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3683 Theory.theory are now identified, referring to the universal
  3684 Context.theory (see Pure/context.ML).  Actual signature and theory
  3685 content is managed as theory data.  The old code and interfaces were
  3686 spread over many files and structures; the new arrangement introduces
  3687 considerable INCOMPATIBILITY to gain more clarity:
  3688 
  3689   Context -- theory management operations (name, identity, inclusion,
  3690     parents, ancestors, merge, etc.), plus generic theory data;
  3691 
  3692   Sign -- logical signature and syntax operations (declaring consts,
  3693     types, etc.), plus certify/read for common entities;
  3694 
  3695   Theory -- logical theory operations (stating axioms, definitions,
  3696     oracles), plus a copy of logical signature operations (consts,
  3697     types, etc.); also a few basic management operations (Theory.copy,
  3698     Theory.merge, etc.)
  3699 
  3700 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3701 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3702 for convenience -- they merely return the theory.
  3703 
  3704 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3705 
  3706 * Pure: the Isar proof context type is already defined early in Pure
  3707 as Context.proof (note that ProofContext.context and Proof.context are
  3708 aliases, where the latter is the preferred name).  This enables other
  3709 Isabelle components to refer to that type even before Isar is present.
  3710 
  3711 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3712 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3713 any of these kinds.  For example, Sign.intern typeK is now
  3714 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3715 Theory.hide_types.  Also note that former
  3716 Theory.hide_classes/types/consts are now
  3717 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3718 internalize their arguments!  INCOMPATIBILITY.
  3719 
  3720 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3721 datatype thmref (with constructors Name and NameSelection) instead of
  3722 plain string -- INCOMPATIBILITY;
  3723 
  3724 * Pure: cases produced by proof methods specify options, where NONE
  3725 means to remove case bindings -- INCOMPATIBILITY in
  3726 (RAW_)METHOD_CASES.
  3727 
  3728 * Pure: the following operations retrieve axioms or theorems from a
  3729 theory node or theory hierarchy, respectively:
  3730 
  3731   Theory.axioms_of: theory -> (string * term) list
  3732   Theory.all_axioms_of: theory -> (string * term) list
  3733   PureThy.thms_of: theory -> (string * thm) list
  3734   PureThy.all_thms_of: theory -> (string * thm) list
  3735 
  3736 * Pure: print_tac now outputs the goal through the trace channel.
  3737 
  3738 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3739 Reference Toplevel.debug (default false) controls detailed printing
  3740 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3741 controls execution profiling -- set to 1 for time and 2 for space
  3742 (both increase the runtime).
  3743 
  3744 * Isar session: The initial use of ROOT.ML is now always timed,
  3745 i.e. the log will show the actual process times, in contrast to the
  3746 elapsed wall-clock time that the outer shell wrapper produces.
  3747 
  3748 * Simplifier: improved handling of bound variables (nameless
  3749 representation, avoid allocating new strings).  Simprocs that invoke
  3750 the Simplifier recursively should use Simplifier.inherit_bounds to
  3751 avoid local name clashes.  Failure to do so produces warnings
  3752 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3753 for further details.
  3754 
  3755 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3756 bindings for all theorems stored within a given theory; this may help
  3757 in porting non-Isar theories to Isar ones, while keeping ML proof
  3758 scripts for the time being.
  3759 
  3760 * ML operator HTML.with_charset specifies the charset begin used for
  3761 generated HTML files.  For example:
  3762 
  3763   HTML.with_charset "utf-8" use_thy "Hebrew";
  3764   HTML.with_charset "utf-8" use_thy "Chinese";
  3765 
  3766 
  3767 *** System ***
  3768 
  3769 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3770 isabelle, isatool etc.).
  3771 
  3772 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3773 isatool doc, isatool mkdir, display_drafts etc.).
  3774 
  3775 * isatool usedir: option -f allows specification of the ML file to be
  3776 used by Isabelle; default is ROOT.ML.
  3777 
  3778 * New isatool version outputs the version identifier of the Isabelle
  3779 distribution being used.
  3780 
  3781 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3782 (containing Boolean satisfiability problems) into Isabelle/HOL
  3783 theories.
  3784 
  3785 
  3786 
  3787 New in Isabelle2004 (April 2004)
  3788 --------------------------------
  3789 
  3790 *** General ***
  3791 
  3792 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3793   Replaces linorder.ML.
  3794 
  3795 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3796   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3797   (\<a>...\<z>), are now considered normal letters, and can therefore
  3798   be used anywhere where an ASCII letter (a...zA...Z) has until
  3799   now. COMPATIBILITY: This obviously changes the parsing of some
  3800   terms, especially where a symbol has been used as a binder, say
  3801   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3802   as an identifier.  Fix it by inserting a space around former
  3803   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3804   existing theory and ML files.
  3805 
  3806 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3807 
  3808 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3809   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3810   a normal (but invisible) letter. For multiple letter subscripts repeat
  3811   \<^isub> like this: x\<^isub>1\<^isub>2.
  3812 
  3813 * Pure: There are now sub-/superscripts that can span more than one
  3814   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3815   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3816   superscript. The new control characters are not identifier parts.
  3817 
  3818 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3819   content of "..." to the latex file instead of \isacntrl... . The "..."
  3820   may consist of any printable characters excluding the end bracket >.
  3821 
  3822 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3823   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3824   declare constants "final", which prevents their being given a definition
  3825   later.  It is useful for constants whose behaviour is fixed axiomatically
  3826   rather than definitionally, such as the meta-logic connectives.
  3827 
  3828 * Pure: 'instance' now handles general arities with general sorts
  3829   (i.e. intersections of classes),
  3830 
  3831 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3832   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3833   It can be changed to alter the colors/layout of generated pages.
  3834 
  3835 
  3836 *** Isar ***
  3837 
  3838 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3839   cut_tac, subgoal_tac and thin_tac:
  3840   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3841     locales are no longer forced to write Isar proof scripts.
  3842     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3843     emulations.
  3844   - INCOMPATIBILITY: names of variables to be instantiated may no
  3845     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3846     This is consistent with the instantiation attribute "where".
  3847 
  3848 * Attributes "where" and "of":
  3849   - Now take type variables of instantiated theorem into account when reading
  3850     the instantiation string.  This fixes a bug that caused instantiated
  3851     theorems to have too special types in some circumstances.
  3852   - "where" permits explicit instantiations of type variables.
  3853 
  3854 * Calculation commands "moreover" and "also" no longer interfere with
  3855   current facts ("this"), admitting arbitrary combinations with "then"
  3856   and derived forms.
  3857 
  3858 * Locales:
  3859   - Goal statements involving the context element "includes" no longer
  3860     generate theorems with internal delta predicates (those ending on
  3861     "_axioms") in the premise.
  3862     Resolve particular premise with <locale>.intro to obtain old form.
  3863   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3864     specification and "includes" elements in goal statement.
  3865   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3866     [intro?] and [elim?] (respectively) by default.
  3867   - Experimental command for instantiation of locales in proof contexts:
  3868         instantiate <label>[<attrs>]: <loc>
  3869     Instantiates locale <loc> and adds all its theorems to the current context
  3870     taking into account their attributes.  Label and attrs are optional
  3871     modifiers, like in theorem declarations.  If present, names of
  3872     instantiated theorems are qualified with <label>, and the attributes
  3873     <attrs> are applied after any attributes these theorems might have already.
  3874       If the locale has assumptions, a chained fact of the form
  3875     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3876     are derived.  The command does not support old-style locales declared
  3877     with "locale (open)".
  3878       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3879 
  3880 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3881   (Isar) contexts.
  3882 
  3883 
  3884 *** HOL ***
  3885 
  3886 * Proof import: new image HOL4 contains the imported library from
  3887   the HOL4 system with about 2500 theorems. It is imported by
  3888   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3889   can be used like any other Isabelle image.  See
  3890   HOL/Import/HOL/README for more information.
  3891 
  3892 * Simplifier:
  3893   - Much improved handling of linear and partial orders.
  3894     Reasoners for linear and partial orders are set up for type classes
  3895     "linorder" and "order" respectively, and are added to the default simpset
  3896     as solvers.  This means that the simplifier can build transitivity chains
  3897     to solve goals from the assumptions.
  3898   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3899     of blast or auto after simplification become unnecessary because the goal
  3900     is solved by simplification already.
  3901 
  3902 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3903     all proved in axiomatic type classes for semirings, rings and fields.
  3904 
  3905 * Numerics:
  3906   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3907     now formalized using the Ring_and_Field theory mentioned above.
  3908   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3909     than before, because now they are set up once in a generic manner.
  3910   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3911     Look for the general versions in Ring_and_Field (and Power if they concern
  3912     exponentiation).
  3913 
  3914 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3915 
  3916 * Records:
  3917   - Record types are now by default printed with their type abbreviation
  3918     instead of the list of all field types. This can be configured via
  3919     the reference "print_record_type_abbr".
  3920   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3921     (not enabled by default).
  3922   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3923     EX x. x = sel r to True (not enabled by default).
  3924   - Tactic "record_split_simp_tac" to split and simplify records added.
  3925 
  3926 * 'specification' command added, allowing for definition by
  3927   specification.  There is also an 'ax_specification' command that
  3928   introduces the new constants axiomatically.
  3929 
  3930 * arith(_tac) is now able to generate counterexamples for reals as well.
  3931 
  3932 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3933 
  3934 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3935   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3936 
  3937 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3938   matrix theory to linear programming.
  3939 
  3940 * Unions and Intersections:
  3941   The latex output syntax of UN and INT has been changed
  3942   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3943   i.e. the index formulae has become a subscript.
  3944   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3945 
  3946 * Unions and Intersections over Intervals:
  3947   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3948   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3949   like in normal math, and corresponding versions for < and for intersection.
  3950 
  3951 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3952   lexicographic dictonary ordering has been added as "lexord".
  3953 
  3954 * ML: the legacy theory structures Int and List have been removed. They had
  3955   conflicted with ML Basis Library structures having the same names.
  3956 
  3957 * 'refute' command added to search for (finite) countermodels.  Only works
  3958   for a fragment of HOL.  The installation of an external SAT solver is
  3959   highly recommended.  See "HOL/Refute.thy" for details.
  3960 
  3961 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3962   formulae under an assignment of free variables to random values.
  3963   In contrast to 'refute', it can deal with inductive datatypes,
  3964   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3965   for examples.
  3966 
  3967 
  3968 *** HOLCF ***
  3969 
  3970 * Streams now come with concatenation and are part of the HOLCF image
  3971 
  3972 
  3973 
  3974 New in Isabelle2003 (May 2003)
  3975 ------------------------------
  3976 
  3977 *** General ***
  3978 
  3979 * Provers/simplifier:
  3980 
  3981   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3982     Assumptions are now subject to complete mutual simplification,
  3983     not just from left to right. The simplifier now preserves
  3984     the order of assumptions.
  3985 
  3986     Potential INCOMPATIBILITY:
  3987 
  3988     -- simp sometimes diverges where the old version did
  3989        not, e.g. invoking simp on the goal
  3990 
  3991         [| P (f x); y = x; f x = f y |] ==> Q
  3992 
  3993        now gives rise to the infinite reduction sequence
  3994 
  3995         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3996 
  3997        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3998        kind of problem.
  3999 
  4000     -- Tactics combining classical reasoner and simplification (such as auto)
  4001        are also affected by this change, because many of them rely on
  4002        simp. They may sometimes diverge as well or yield a different numbers
  4003        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  4004        in case of problems. Sometimes subsequent calls to the classical
  4005        reasoner will fail because a preceeding call to the simplifier too
  4006        eagerly simplified the goal, e.g. deleted redundant premises.
  4007 
  4008   - The simplifier trace now shows the names of the applied rewrite rules
  4009 
  4010   - You can limit the number of recursive invocations of the simplifier
  4011     during conditional rewriting (where the simplifie tries to solve the
  4012     conditions before applying the rewrite rule):
  4013     ML "simp_depth_limit := n"
  4014     where n is an integer. Thus you can force termination where previously
  4015     the simplifier would diverge.
  4016 
  4017   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  4018 
  4019   - No longer aborts on failed congruence proof.  Instead, the
  4020     congruence is ignored.
  4021 
  4022 * Pure: New generic framework for extracting programs from constructive
  4023   proofs. See HOL/Extraction.thy for an example instantiation, as well
  4024   as HOL/Extraction for some case studies.
  4025 
  4026 * Pure: The main goal of the proof state is no longer shown by default, only
  4027 the subgoals. This behaviour is controlled by a new flag.
  4028    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  4029 (ML: Proof.show_main_goal).
  4030 
  4031 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  4032 rules whose conclusion matches subgoal 1:
  4033       PG menu: Isabelle/Isar -> Show me -> matching rules
  4034 The rules are ordered by how closely they match the subgoal.
  4035 In particular, rules that solve a subgoal outright are displayed first
  4036 (or rather last, the way they are printed).
  4037 (ML: ProofGeneral.print_intros())
  4038 
  4039 * Pure: New flag trace_unify_fail causes unification to print
  4040 diagnostic information (PG: in trace buffer) when it fails. This is
  4041 useful for figuring out why single step proofs like rule, erule or
  4042 assumption failed.
  4043 
  4044 * Pure: Locale specifications now produce predicate definitions
  4045 according to the body of text (covering assumptions modulo local
  4046 definitions); predicate "loc_axioms" covers newly introduced text,
  4047 while "loc" is cumulative wrt. all included locale expressions; the
  4048 latter view is presented only on export into the global theory
  4049 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  4050 on the old view without predicates;
  4051 
  4052 * Pure: predefined locales "var" and "struct" are useful for sharing
  4053 parameters (as in CASL, for example); just specify something like
  4054 ``var x + var y + struct M'' as import;
  4055 
  4056 * Pure: improved thms_containing: proper indexing of facts instead of
  4057 raw theorems; check validity of results wrt. current name space;
  4058 include local facts of proof configuration (also covers active
  4059 locales), cover fixed variables in index; may use "_" in term
  4060 specification; an optional limit for the number of printed facts may
  4061 be given (the default is 40);
  4062 
  4063 * Pure: disallow duplicate fact bindings within new-style theory files
  4064 (batch-mode only);
  4065 
  4066 * Provers: improved induct method: assumptions introduced by case
  4067 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  4068 the goal statement); "foo" still refers to all facts collectively;
  4069 
  4070 * Provers: the function blast.overloaded has been removed: all constants
  4071 are regarded as potentially overloaded, which improves robustness in exchange
  4072 for slight decrease in efficiency;
  4073 
  4074 * Provers/linorder: New generic prover for transitivity reasoning over
  4075 linear orders.  Note: this prover is not efficient!
  4076 
  4077 * Isar: preview of problems to finish 'show' now produce an error
  4078 rather than just a warning (in interactive mode);
  4079 
  4080 
  4081 *** HOL ***
  4082 
  4083 * arith(_tac)
  4084 
  4085  - Produces a counter example if it cannot prove a goal.
  4086    Note that the counter example may be spurious if the goal is not a formula
  4087    of quantifier-free linear arithmetic.
  4088    In ProofGeneral the counter example appears in the trace buffer.
  4089 
  4090  - Knows about div k and mod k where k is a numeral of type nat or int.
  4091 
  4092  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  4093    linear arithmetic fails. This takes account of quantifiers and divisibility.
  4094    Presburger arithmetic can also be called explicitly via presburger(_tac).
  4095 
  4096 * simp's arithmetic capabilities have been enhanced a bit: it now
  4097 takes ~= in premises into account (by performing a case split);
  4098 
  4099 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  4100 are distributed over a sum of terms;
  4101 
  4102 * New tactic "trans_tac" and method "trans" instantiate
  4103 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  4104 "<=", "<" and "=").
  4105 
  4106 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  4107 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  4108 
  4109 * 'typedef' command has new option "open" to suppress the set
  4110 definition;
  4111 
  4112 * functions Min and Max on finite sets have been introduced (theory
  4113 Finite_Set);
  4114 
  4115 * attribute [symmetric] now works for relations as well; it turns
  4116 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4117 
  4118 * induct over a !!-quantified statement (say !!x1..xn):
  4119   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4120 
  4121 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4122 %x. None. Warning: empty_def now refers to the previously hidden definition
  4123 of the empty set.
  4124 
  4125 * Algebra: formalization of classical algebra.  Intended as base for
  4126 any algebraic development in Isabelle.  Currently covers group theory
  4127 (up to Sylow's theorem) and ring theory (Universal Property of
  4128 Univariate Polynomials).  Contributions welcome;
  4129 
  4130 * GroupTheory: deleted, since its material has been moved to Algebra;
  4131 
  4132 * Complex: new directory of the complex numbers with numeric constants,
  4133 nonstandard complex numbers, and some complex analysis, standard and
  4134 nonstandard (Jacques Fleuriot);
  4135 
  4136 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4137 
  4138 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4139 Fleuriot);
  4140 
  4141 * Real/HahnBanach: updated and adapted to locales;
  4142 
  4143 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4144 Gray and Kramer);
  4145 
  4146 * UNITY: added the Meier-Sanders theory of progress sets;
  4147 
  4148 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4149 as abstract algorithms, instantiated to the JVM;
  4150 
  4151 * Bali: Java source language formalization. Type system, operational
  4152 semantics, axiomatic semantics. Supported language features:
  4153 classes, interfaces, objects,virtual methods, static methods,
  4154 static/instance fields, arrays, access modifiers, definite
  4155 assignment, exceptions.
  4156 
  4157 
  4158 *** ZF ***
  4159 
  4160 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4161 universe, etc.);
  4162 
  4163 * Main ZF: virtually all theories converted to new-style format;
  4164 
  4165 
  4166 *** ML ***
  4167 
  4168 * Pure: Tactic.prove provides sane interface for internal proofs;
  4169 omits the infamous "standard" operation, so this is more appropriate
  4170 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4171 
  4172 * Pure: improved error reporting of simprocs;
  4173 
  4174 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4175 up simprocs;
  4176 
  4177 
  4178 *** Document preparation ***
  4179 
  4180 * uses \par instead of \\ for line breaks in theory text. This may
  4181 shift some page breaks in large documents. To get the old behaviour
  4182 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4183 
  4184 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4185 other packages
  4186 
  4187 * \<euro> now needs package babel/greek instead of marvosym (which
  4188 broke \Rightarrow)
  4189 
  4190 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4191 textcomp package)
  4192 
  4193 
  4194 
  4195 New in Isabelle2002 (March 2002)
  4196 --------------------------------
  4197 
  4198 *** Document preparation ***
  4199 
  4200 * greatly simplified document preparation setup, including more
  4201 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4202 instructive isatool mkdir; users should basically be able to get
  4203 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4204 users may run a separate document processing stage manually like this:
  4205 "isatool usedir -D output HOL Test && isatool document Test/output";
  4206 
  4207 * theory dependency graph may now be incorporated into documents;
  4208 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4209 with \includegraphics of LaTeX;
  4210 
  4211 * proper spacing of consecutive markup elements, especially text
  4212 blocks after section headings;
  4213 
  4214 * support bold style (for single symbols only), input syntax is like
  4215 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4216 
  4217 * \<bullet> is now output as bold \cdot by default, which looks much
  4218 better in printed text;
  4219 
  4220 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4221 note that these symbols are currently unavailable in Proof General /
  4222 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4223 
  4224 * isatool latex no longer depends on changed TEXINPUTS, instead
  4225 isatool document copies the Isabelle style files to the target
  4226 location;
  4227 
  4228 
  4229 *** Isar ***
  4230 
  4231 * Pure/Provers: improved proof by cases and induction;
  4232   - 'case' command admits impromptu naming of parameters (such as
  4233     "case (Suc n)");
  4234   - 'induct' method divinates rule instantiation from the inductive
  4235     claim; no longer requires excessive ?P bindings for proper
  4236     instantiation of cases;
  4237   - 'induct' method properly enumerates all possibilities of set/type
  4238     rules; as a consequence facts may be also passed through *type*
  4239     rules without further ado;
  4240   - 'induct' method now derives symbolic cases from the *rulified*
  4241     rule (before it used to rulify cases stemming from the internal
  4242     atomized version); this means that the context of a non-atomic
  4243     statement becomes is included in the hypothesis, avoiding the
  4244     slightly cumbersome show "PROP ?case" form;
  4245   - 'induct' may now use elim-style induction rules without chaining
  4246     facts, using ``missing'' premises from the goal state; this allows
  4247     rules stemming from inductive sets to be applied in unstructured
  4248     scripts, while still benefitting from proper handling of non-atomic
  4249     statements; NB: major inductive premises need to be put first, all
  4250     the rest of the goal is passed through the induction;
  4251   - 'induct' proper support for mutual induction involving non-atomic
  4252     rule statements (uses the new concept of simultaneous goals, see
  4253     below);
  4254   - append all possible rule selections, but only use the first
  4255     success (no backtracking);
  4256   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4257   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4258   - added 'print_induct_rules' (covered by help item in recent Proof
  4259     General versions);
  4260   - moved induct/cases attributes to Pure, methods to Provers;
  4261   - generic method setup instantiated for FOL and HOL;
  4262 
  4263 * Pure: support multiple simultaneous goal statements, for example
  4264 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4265 meta-level mechanism, this acts as if several individual goals had
  4266 been stated separately; in particular common proof methods need to be
  4267 repeated in order to cover all claims; note that a single elimination
  4268 step is *not* sufficient to establish the two conjunctions, so this
  4269 fails:
  4270 
  4271   assume "A & B" then have A and B ..   (*".." fails*)
  4272 
  4273 better use "obtain" in situations as above; alternative refer to
  4274 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4275 
  4276 * Pure: proper integration with ``locales''; unlike the original
  4277 version by Florian Kammller, Isar locales package high-level proof
  4278 contexts rather than raw logical ones (e.g. we admit to include
  4279 attributes everywhere); operations on locales include merge and
  4280 rename; support for implicit arguments (``structures''); simultaneous
  4281 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4282 some examples;
  4283 
  4284 * Pure: the following commands have been ``localized'', supporting a
  4285 target locale specification "(in name)": 'lemma', 'theorem',
  4286 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4287 stored both within the locale and at the theory level (exported and
  4288 qualified by the locale name);
  4289 
  4290 * Pure: theory goals may now be specified in ``long'' form, with
  4291 ad-hoc contexts consisting of arbitrary locale elements. for example
  4292 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4293 definitions may be given, too); the result is a meta-level rule with
  4294 the context elements being discharged in the obvious way;
  4295 
  4296 * Pure: new proof command 'using' allows to augment currently used
  4297 facts after a goal statement ('using' is syntactically analogous to
  4298 'apply', but acts on the goal's facts only); this allows chained facts
  4299 to be separated into parts given before and after a claim, as in
  4300 ``from a and b have C using d and e <proof>'';
  4301 
  4302 * Pure: renamed "antecedent" case to "rule_context";
  4303 
  4304 * Pure: new 'judgment' command records explicit information about the
  4305 object-logic embedding (used by several tools internally); no longer
  4306 use hard-wired "Trueprop";
  4307 
  4308 * Pure: added 'corollary' command;
  4309 
  4310 * Pure: fixed 'token_translation' command;
  4311 
  4312 * Pure: removed obsolete 'exported' attribute;
  4313 
  4314 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4315 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4316 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4317 
  4318 * Pure: method 'atomize' presents local goal premises as object-level
  4319 statements (atomic meta-level propositions); setup controlled via
  4320 rewrite rules declarations of 'atomize' attribute; example
  4321 application: 'induct' method with proper rule statements in improper
  4322 proof *scripts*;
  4323 
  4324 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4325 now consider the syntactic context of assumptions, giving a better
  4326 chance to get type-inference of the arguments right (this is
  4327 especially important for locales);
  4328 
  4329 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4330 mode;
  4331 
  4332 * Pure/obtain: the formal conclusion "thesis", being marked as
  4333 ``internal'', may no longer be reference directly in the text;
  4334 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4335 situations;
  4336 
  4337 * Pure: generic 'sym' attribute which declares a rule both as pure
  4338 'elim?' and for the 'symmetric' operation;
  4339 
  4340 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4341 text; the fixed correlation with particular command syntax has been
  4342 discontinued;
  4343 
  4344 * Pure: new method 'rules' is particularly well-suited for proof
  4345 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4346 but often produces more compact proof terms with less detours;
  4347 
  4348 * Pure/Provers/classical: simplified integration with pure rule
  4349 attributes and methods; the classical "intro?/elim?/dest?"
  4350 declarations coincide with the pure ones; the "rule" method no longer
  4351 includes classically swapped intros; "intro" and "elim" methods no
  4352 longer pick rules from the context; also got rid of ML declarations
  4353 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4354 INCOMPATIBILITY;
  4355 
  4356 * Provers/classical: attribute 'swapped' produces classical inversions
  4357 of introduction rules;
  4358 
  4359 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4360 rules instead of full simplifier context; 'iff' attribute handles
  4361 conditional rules;
  4362 
  4363 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4364 
  4365 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4366 "(permissive)" option to recover old behavior;
  4367 
  4368 * HOL: 'inductive' no longer features separate (collective) attributes
  4369 for 'intros' (was found too confusing);
  4370 
  4371 * HOL: properly declared induction rules less_induct and
  4372 wf_induct_rule;
  4373 
  4374 
  4375 *** HOL ***
  4376 
  4377 * HOL: moved over to sane numeral syntax; the new policy is as
  4378 follows:
  4379 
  4380   - 0 and 1 are polymorphic constants, which are defined on any
  4381   numeric type (nat, int, real etc.);
  4382 
  4383   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4384   binary representation internally;
  4385 
  4386   - type nat has special constructor Suc, and generally prefers Suc 0
  4387   over 1::nat and Suc (Suc 0) over 2::nat;
  4388 
  4389 This change may cause significant problems of INCOMPATIBILITY; here
  4390 are some hints on converting existing sources:
  4391 
  4392   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4393   entities, so expressions involving "-" (unary or binary minus) need
  4394   to be spaced properly;
  4395 
  4396   - existing occurrences of "1" may need to be constraint "1::nat" or
  4397   even replaced by Suc 0; similar for old "2";
  4398 
  4399   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4400 
  4401   - remove all special provisions on numerals in proofs;
  4402 
  4403 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4404 representation (depends on bin_arith_simps in the default context);
  4405 
  4406 * HOL: symbolic syntax for x^2 (numeral 2);
  4407 
  4408 * HOL: the class of all HOL types is now called "type" rather than
  4409 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4410 in axclass/classes, instance/arities, and (usually rare) occurrences
  4411 in typings (of consts etc.); internally the class is called
  4412 "HOL.type", ML programs should refer to HOLogic.typeS;
  4413 
  4414 * HOL/record package improvements:
  4415   - new derived operations "fields" to build a partial record section,
  4416     "extend" to promote a fixed record to a record scheme, and
  4417     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4418     declared as simp by default;
  4419   - shared operations ("more", "fields", etc.) now need to be always
  4420     qualified) --- potential INCOMPATIBILITY;
  4421   - removed "make_scheme" operations (use "make" with "extend") --
  4422     INCOMPATIBILITY;
  4423   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4424   - provides cases/induct rules for use with corresponding Isar
  4425     methods (for concrete records, record schemes, concrete more
  4426     parts, and schematic more parts -- in that order);
  4427   - internal definitions directly based on a light-weight abstract
  4428     theory of product types over typedef rather than datatype;
  4429 
  4430 * HOL: generic code generator for generating executable ML code from
  4431 specifications; specific support for HOL constructs such as inductive
  4432 datatypes and sets, as well as recursive functions; can be invoked
  4433 via 'generate_code' theory section;
  4434 
  4435 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4436 
  4437 * HOL: consolidated and renamed several theories.  In particular:
  4438         Ord.thy has been absorbed into HOL.thy
  4439         String.thy has been absorbed into List.thy
  4440 
  4441 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4442 (beware of argument permutation!);
  4443 
  4444 * HOL: linorder_less_split superseded by linorder_cases;
  4445 
  4446 * HOL/List: "nodups" renamed to "distinct";
  4447 
  4448 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4449 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4450   - Ex_def has changed, now need to use some_eq_ex
  4451 
  4452 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4453 in this (rare) case use:
  4454 
  4455   delSWrapper "split_all_tac"
  4456   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4457 
  4458 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4459 MAY FAIL;
  4460 
  4461 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4462 Isabelle's type classes, ^ on functions and relations has too general
  4463 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4464 necessary to attach explicit type constraints;
  4465 
  4466 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4467 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4468 renamed accordingly (eg "compI" -> "rel_compI").
  4469 
  4470 * HOL: syntax translations now work properly with numerals and records
  4471 expressions;
  4472 
  4473 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4474 of "lam" -- INCOMPATIBILITY;
  4475 
  4476 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4477 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4478 renamed "Product_Type.unit";
  4479 
  4480 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4481 
  4482 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4483 the "cases" method);
  4484 
  4485 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4486 Florian Kammller);
  4487 
  4488 * HOL/IMP: updated and converted to new-style theory format; several
  4489 parts turned into readable document, with proper Isar proof texts and
  4490 some explanations (by Gerwin Klein);
  4491 
  4492 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4493 
  4494 * HOL-Hyperreal is now a logic image;
  4495 
  4496 
  4497 *** HOLCF ***
  4498 
  4499 * Isar: consts/constdefs supports mixfix syntax for continuous
  4500 operations;
  4501 
  4502 * Isar: domain package adapted to new-style theory format, e.g. see
  4503 HOLCF/ex/Dnat.thy;
  4504 
  4505 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4506 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4507 lift.induct_tac, always use UU instead of Undef;
  4508 
  4509 * HOLCF/IMP: updated and converted to new-style theory;
  4510 
  4511 
  4512 *** ZF ***
  4513 
  4514 * Isar: proper integration of logic-specific tools and packages,
  4515 including theory commands '(co)inductive', '(co)datatype',
  4516 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4517 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4518 
  4519 * theory Main no longer includes AC; for the Axiom of Choice, base
  4520 your theory on Main_ZFC;
  4521 
  4522 * the integer library now covers quotients and remainders, with many
  4523 laws relating division to addition, multiplication, etc.;
  4524 
  4525 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4526 typeless version of the formalism;
  4527 
  4528 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4529 format;
  4530 
  4531 * ZF/Induct: new directory for examples of inductive definitions,
  4532 including theory Multiset for multiset orderings; converted to
  4533 new-style theory format;
  4534 
  4535 * ZF: many new theorems about lists, ordinals, etc.;
  4536 
  4537 
  4538 *** General ***
  4539 
  4540 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4541 variable proof controls level of detail: 0 = no proofs (only oracle
  4542 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4543 also ref manual for further ML interfaces;
  4544 
  4545 * Pure/axclass: removed obsolete ML interface
  4546 goal_subclass/goal_arity;
  4547 
  4548 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4549 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4550 separate tokens, so expressions involving minus need to be spaced
  4551 properly;
  4552 
  4553 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4554 rather than "infixl" or "infixr";
  4555 
  4556 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4557 sort constraint specifications in type inference; e.g. "x::_::foo"
  4558 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4559 type variable);
  4560 
  4561 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4562 control output of nested => (types); the default behavior is
  4563 "type_brackets";
  4564 
  4565 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4566 tokens into AST constants;
  4567 
  4568 * Pure/syntax: prefer later declarations of translations and print
  4569 translation functions; potential INCOMPATIBILITY: need to reverse
  4570 multiple declarations for same syntax element constant;
  4571 
  4572 * Pure/show_hyps reset by default (in accordance to existing Isar
  4573 practice);
  4574 
  4575 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4576 addSafter;
  4577 
  4578 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4579 as well;
  4580 
  4581 * system: tested support for MacOS X; should be able to get Isabelle +
  4582 Proof General to work in a plain Terminal after installing Poly/ML
  4583 (e.g. from the Isabelle distribution area) and GNU bash alone
  4584 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4585 support requires further installations, e.g. from
  4586 http://fink.sourceforge.net/);
  4587 
  4588 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4589 
  4590 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4591 of 40 MB), cf. ML_OPTIONS;
  4592 
  4593 * system: Proof General keywords specification is now part of the
  4594 Isabelle distribution (see etc/isar-keywords.el);
  4595 
  4596 * system: support for persistent Proof General sessions (refrain from
  4597 outdating all loaded theories on startup); user may create writable
  4598 logic images like this: ``isabelle -q HOL Test'';
  4599 
  4600 * system: smart selection of Isabelle process versus Isabelle
  4601 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4602 run both "isabelle" and "Isabelle" even if file names are badly
  4603 damaged (executable inspects the case of the first letter of its own
  4604 name); added separate "isabelle-process" and "isabelle-interface";
  4605 
  4606 * system: refrain from any attempt at filtering input streams; no
  4607 longer support ``8bit'' encoding of old isabelle font, instead proper
  4608 iso-latin characters may now be used; the related isatools
  4609 "symbolinput" and "nonascii" have disappeared as well;
  4610 
  4611 * system: removed old "xterm" interface (the print modes "xterm" and
  4612 "xterm_color" are still available for direct use in a suitable
  4613 terminal);
  4614 
  4615 
  4616 
  4617 New in Isabelle99-2 (February 2001)
  4618 -----------------------------------
  4619 
  4620 *** Overview of INCOMPATIBILITIES ***
  4621 
  4622 * HOL: please note that theories in the Library and elsewhere often use the
  4623 new-style (Isar) format; to refer to their theorems in an ML script you must
  4624 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4625 
  4626 * HOL: inductive package no longer splits induction rule aggressively,
  4627 but only as far as specified by the introductions given; the old
  4628 format may be recovered via ML function complete_split_rule or attribute
  4629 'split_rule (complete)';
  4630 
  4631 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4632 gfp_Tarski to gfp_unfold;
  4633 
  4634 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4635 
  4636 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4637 relation); infix "^^" has been renamed "``"; infix "``" has been
  4638 renamed "`"; "univalent" has been renamed "single_valued";
  4639 
  4640 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4641 operation;
  4642 
  4643 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4644 
  4645 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4646 
  4647 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4648 consequence, it is no longer monotonic wrt. the local goal context
  4649 (which is now passed through the inductive cases);
  4650 
  4651 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4652 \<gg> to \<ggreater>;
  4653 
  4654 
  4655 *** Document preparation ***
  4656 
  4657 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4658 available: are "it" for near math-mode best-style output, "sl" for
  4659 slanted text style, and "tt" for plain type-writer; if no
  4660 \isabellestyle command is given, output is according to slanted
  4661 type-writer);
  4662 
  4663 * support sub/super scripts (for single symbols only), input syntax is
  4664 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4665 
  4666 * some more standard symbols; see Appendix A of the system manual for
  4667 the complete list of symbols defined in isabellesym.sty;
  4668 
  4669 * improved isabelle style files; more abstract symbol implementation
  4670 (should now use \isamath{...} and \isatext{...} in custom symbol
  4671 definitions);
  4672 
  4673 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4674 state; Note that presentation of goal states does not conform to
  4675 actual human-readable proof documents.  Please do not include goal
  4676 states into document output unless you really know what you are doing!
  4677 
  4678 * proper indentation of antiquoted output with proportional LaTeX
  4679 fonts;
  4680 
  4681 * no_document ML operator temporarily disables LaTeX document
  4682 generation;
  4683 
  4684 * isatool unsymbolize tunes sources for plain ASCII communication;
  4685 
  4686 
  4687 *** Isar ***
  4688 
  4689 * Pure: Isar now suffers initial goal statements to contain unbound
  4690 schematic variables (this does not conform to actual readable proof
  4691 documents, due to unpredictable outcome and non-compositional proof
  4692 checking); users who know what they are doing may use schematic goals
  4693 for Prolog-style synthesis of proven results;
  4694 
  4695 * Pure: assumption method (an implicit finishing) now handles actual
  4696 rules as well;
  4697 
  4698 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4699 initial goal, declare "that" only as Pure intro (only for single
  4700 steps); the "that" rule assumption may now be involved in implicit
  4701 finishing, thus ".." becomes a feasible for trivial obtains;
  4702 
  4703 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4704 instance proofs may be performed by "..";
  4705 
  4706 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4707 statements as well;
  4708 
  4709 * Pure: more robust selection of calculational rules;
  4710 
  4711 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4712 rule (as well as the assumption rule);
  4713 
  4714 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4715 lemmas, using the graph browser tool;
  4716 
  4717 * Pure: predict failure of "show" in interactive mode;
  4718 
  4719 * Pure: 'thms_containing' now takes actual terms as arguments;
  4720 
  4721 * HOL: improved method 'induct' --- now handles non-atomic goals
  4722 (potential INCOMPATIBILITY); tuned error handling;
  4723 
  4724 * HOL: cases and induct rules now provide explicit hints about the
  4725 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4726 any remaining facts are inserted into the goal verbatim;
  4727 
  4728 * HOL: local contexts (aka cases) may now contain term bindings as
  4729 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4730 the result to be shown in each case;
  4731 
  4732 * HOL: added 'recdef_tc' command;
  4733 
  4734 * isatool convert assists in eliminating legacy ML scripts;
  4735 
  4736 
  4737 *** HOL ***
  4738 
  4739 * HOL/Library: a collection of generic theories to be used together
  4740 with main HOL; the theory loader path already includes this directory
  4741 by default; the following existing theories have been moved here:
  4742 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4743 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4744 
  4745 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4746 modelling and verification task performed in Isabelle/HOL +
  4747 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4748 
  4749 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4750 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4751 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4752 'domain', this makes the theory consistent with mathematical
  4753 literature;
  4754 
  4755 * HOL basics: added overloaded operations "inverse" and "divide"
  4756 (infix "/"), syntax for generic "abs" operation, generic summation
  4757 operator \<Sum>;
  4758 
  4759 * HOL/typedef: simplified package, provide more useful rules (see also
  4760 HOL/subset.thy);
  4761 
  4762 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4763 now expressed as a proper nested rule (old-style tactic scripts may
  4764 require atomize_strip_tac to cope with non-atomic premises);
  4765 
  4766 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4767 to "split_conv" (old name still available for compatibility);
  4768 
  4769 * HOL: improved concrete syntax for strings (e.g. allows translation
  4770 rules with string literals);
  4771 
  4772 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4773  and Fleuriot's mechanization of analysis, including the transcendental
  4774  functions for the reals;
  4775 
  4776 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4777 
  4778 
  4779 *** CTT ***
  4780 
  4781 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4782 "lam" is displayed as TWO lambda-symbols
  4783 
  4784 * CTT: theory Main now available, containing everything (that is, Bool
  4785 and Arith);
  4786 
  4787 
  4788 *** General ***
  4789 
  4790 * Pure: the Simplifier has been implemented properly as a derived rule
  4791 outside of the actual kernel (at last!); the overall performance
  4792 penalty in practical applications is about 50%, while reliability of
  4793 the Isabelle inference kernel has been greatly improved;
  4794 
  4795 * print modes "brackets" and "no_brackets" control output of nested =>
  4796 (types) and ==> (props); the default behaviour is "brackets";
  4797 
  4798 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4799 as assumptions as well;
  4800 
  4801 * system: support Poly/ML 4.0;
  4802 
  4803 * system: isatool install handles KDE version 1 or 2;
  4804 
  4805 
  4806 
  4807 New in Isabelle99-1 (October 2000)
  4808 ----------------------------------
  4809 
  4810 *** Overview of INCOMPATIBILITIES ***
  4811 
  4812 * HOL: simplification of natural numbers is much changed; to partly
  4813 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4814 issue the following ML commands:
  4815 
  4816   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4817   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4818 
  4819 * HOL: simplification no longer dives into case-expressions; this is
  4820 controlled by "t.weak_case_cong" for each datatype t;
  4821 
  4822 * HOL: nat_less_induct renamed to less_induct;
  4823 
  4824 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4825 fixsome to patch .thy and .ML sources automatically;
  4826 
  4827   select_equality  -> some_equality
  4828   select_eq_Ex     -> some_eq_ex
  4829   selectI2EX       -> someI2_ex
  4830   selectI2         -> someI2
  4831   selectI          -> someI
  4832   select1_equality -> some1_equality
  4833   Eps_sym_eq       -> some_sym_eq_trivial
  4834   Eps_eq           -> some_eq_trivial
  4835 
  4836 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4837 
  4838 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4839 instead);
  4840 
  4841 * HOL: the recursion equations generated by 'recdef' are now called
  4842 f.simps instead of f.rules;
  4843 
  4844 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4845 
  4846 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4847 sometimes be needed;
  4848 
  4849 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4850 
  4851 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4852 
  4853 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4854 product is now "<*>" instead of "Times"; the lexicographic product is
  4855 now "<*lex*>" instead of "**";
  4856 
  4857 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4858 of main HOL, but was unused); better use HOL's datatype package;
  4859 
  4860 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4861 the old syntax may be recovered as follows:
  4862 
  4863   syntax (symbols)
  4864     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4865       (infixl "\\<oplus>" 100)
  4866 
  4867 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4868 
  4869 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4870 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4871 internally;
  4872 
  4873 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4874 changed from A/r to A//r;
  4875 
  4876 * ZF: new treatment of arithmetic (nat & int) may break some old
  4877 proofs;
  4878 
  4879 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4880 rulify -> rule_format, elimify -> elim_format, ...);
  4881 
  4882 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4883 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4884 should have to change intro!! to intro? only); replaced "delrule" by
  4885 "rule del";
  4886 
  4887 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4888 
  4889 * Provers: strengthened force_tac by using new first_best_tac;
  4890 
  4891 * LaTeX document preparation: several changes of isabelle.sty (see
  4892 lib/texinputs);
  4893 
  4894 
  4895 *** Document preparation ***
  4896 
  4897 * formal comments (text blocks etc.) in new-style theories may now
  4898 contain antiquotations of thm/prop/term/typ/text to be presented
  4899 according to latex print mode; concrete syntax is like this:
  4900 @{term[show_types] "f(x) = a + x"};
  4901 
  4902 * isatool mkdir provides easy setup of Isabelle session directories,
  4903 including proper document sources;
  4904 
  4905 * generated LaTeX sources are now deleted after successful run
  4906 (isatool document -c); may retain a copy somewhere else via -D option
  4907 of isatool usedir;
  4908 
  4909 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4910 style files, achieving self-contained LaTeX sources and simplifying
  4911 LaTeX debugging;
  4912 
  4913 * old-style theories now produce (crude) LaTeX output as well;
  4914 
  4915 * browser info session directories are now self-contained (may be put
  4916 on WWW server seperately); improved graphs of nested sessions; removed
  4917 graph for 'all sessions';
  4918 
  4919 * several improvements in isabelle style files; \isabellestyle{it}
  4920 produces fake math mode output; \isamarkupheader is now \section by
  4921 default; see lib/texinputs/isabelle.sty etc.;
  4922 
  4923 
  4924 *** Isar ***
  4925 
  4926 * Isar/Pure: local results and corresponding term bindings are now
  4927 subject to Hindley-Milner polymorphism (similar to ML); this
  4928 accommodates incremental type-inference very nicely;
  4929 
  4930 * Isar/Pure: new derived language element 'obtain' supports
  4931 generalized existence reasoning;
  4932 
  4933 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4934 support accumulation of results, without applying any rules yet;
  4935 useful to collect intermediate results without explicit name
  4936 references, and for use with transitivity rules with more than 2
  4937 premises;
  4938 
  4939 * Isar/Pure: scalable support for case-analysis type proofs: new
  4940 'case' language element refers to local contexts symbolically, as
  4941 produced by certain proof methods; internally, case names are attached
  4942 to theorems as "tags";
  4943 
  4944 * Isar/Pure: theory command 'hide' removes declarations from
  4945 class/type/const name spaces;
  4946 
  4947 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4948 indicate potential overloading;
  4949 
  4950 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4951 
  4952 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4953 "{a,b,c}" instead of {a,b,c};
  4954 
  4955 * Isar/Pure now provides its own version of intro/elim/dest
  4956 attributes; useful for building new logics, but beware of confusion
  4957 with the version in Provers/classical;
  4958 
  4959 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4960 case name 'antecedent';
  4961 
  4962 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4963 to the current context is now done automatically);
  4964 
  4965 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4966 for definining proof methods in ML;
  4967 
  4968 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4969 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4970 most cases, one should have to change intro!! to intro? only);
  4971 replaced "delrule" by "rule del";
  4972 
  4973 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4974 'symmetric' attribute (the latter supercedes [RS sym]);
  4975 
  4976 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4977 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4978 well (including splits);
  4979 
  4980 * Isar/Provers: Simplifier and Classical methods now support all kind
  4981 of modifiers used in the past, including 'cong', 'iff', etc.
  4982 
  4983 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4984 of Simplifier and Classical reasoner);
  4985 
  4986 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4987 now support named cases; major packages (inductive, datatype, primrec,
  4988 recdef) support case names and properly name parameters;
  4989 
  4990 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4991 monotonicity conditions are extracted to be proven at end of
  4992 calculations;
  4993 
  4994 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4995 method anyway;
  4996 
  4997 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4998 split_if split_if_asm; datatype package provides theorems foo.splits =
  4999 foo.split foo.split_asm for each datatype;
  5000 
  5001 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  5002 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  5003 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  5004 use "(cases (simplified))" method in proper proof texts);
  5005 
  5006 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  5007 
  5008 * Isar: names of theorems etc. may be natural numbers as well;
  5009 
  5010 * Isar: 'pr' command: optional arguments for goals_limit and
  5011 ProofContext.prems_limit; no longer prints theory contexts, but only
  5012 proof states;
  5013 
  5014 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  5015 additional print modes to be specified; e.g. "pr(latex)" will print
  5016 proof state according to the Isabelle LaTeX style;
  5017 
  5018 * Isar: improved support for emulating tactic scripts, including proof
  5019 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  5020 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  5021 (for HOL datatypes);
  5022 
  5023 * Isar: simplified (more robust) goal selection of proof methods: 1st
  5024 goal, all goals, or explicit goal specifier (tactic emulation); thus
  5025 'proof method scripts' have to be in depth-first order;
  5026 
  5027 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  5028 
  5029 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  5030 should instead use individual commands for printing items
  5031 (print_commands, print_methods etc.);
  5032 
  5033 * Isar: added 'nothing' --- the empty list of theorems;
  5034 
  5035 
  5036 *** HOL ***
  5037 
  5038 * HOL/MicroJava: formalization of a fragment of Java, together with a
  5039 corresponding virtual machine and a specification of its bytecode
  5040 verifier and a lightweight bytecode verifier, including proofs of
  5041 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  5042 Cornelia Pusch (see also the homepage of project Bali at
  5043 http://isabelle.in.tum.de/Bali/);
  5044 
  5045 * HOL/Algebra: new theory of rings and univariate polynomials, by
  5046 Clemens Ballarin;
  5047 
  5048 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  5049 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  5050 Rasmussen;
  5051 
  5052 * HOL/Lattice: fundamental concepts of lattice theory and order
  5053 structures, including duals, properties of bounds versus algebraic
  5054 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  5055 Theorem for complete lattices etc.; may also serve as a demonstration
  5056 for abstract algebraic reasoning using axiomatic type classes, and
  5057 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  5058 
  5059 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  5060 von Oheimb;
  5061 
  5062 * HOL/IMPP: extension of IMP with local variables and mutually
  5063 recursive procedures, by David von Oheimb;
  5064 
  5065 * HOL/Lambda: converted into new-style theory and document;
  5066 
  5067 * HOL/ex/Multiquote: example of multiple nested quotations and
  5068 anti-quotations -- basically a generalized version of de-Bruijn
  5069 representation; very useful in avoiding lifting of operations;
  5070 
  5071 * HOL/record: added general record equality rule to simpset; fixed
  5072 select-update simplification procedure to handle extended records as
  5073 well; admit "r" as field name;
  5074 
  5075 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  5076 other numeric types and also as the identity of groups, rings, etc.;
  5077 
  5078 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  5079 Types nat and int belong to this axclass;
  5080 
  5081 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  5082    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  5083    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  5084   two terms #m*u and #n*u are replaced by #(m+n)*u
  5085     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  5086   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  5087     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  5088 
  5089 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  5090 powerful prover for predicate logic but knows nothing of clasets; see
  5091 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  5092 
  5093 * HOL: new version of "case_tac" subsumes both boolean case split and
  5094 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  5095 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  5096 
  5097 * HOL: simplification no longer dives into case-expressions: only the
  5098 selector expression is simplified, but not the remaining arms; to
  5099 enable full simplification of case-expressions for datatype t, you may
  5100 remove t.weak_case_cong from the simpset, either globally (Delcongs
  5101 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  5102 
  5103 * HOL/recdef: the recursion equations generated by 'recdef' for
  5104 function 'f' are now called f.simps instead of f.rules; if all
  5105 termination conditions are proved automatically, these simplification
  5106 rules are added to the simpset, as in primrec; rules may be named
  5107 individually as well, resulting in a separate list of theorems for
  5108 each equation;
  5109 
  5110 * HOL/While is a new theory that provides a while-combinator. It
  5111 permits the definition of tail-recursive functions without the
  5112 provision of a termination measure. The latter is necessary once the
  5113 invariant proof rule for while is applied.
  5114 
  5115 * HOL: new (overloaded) notation for the set of elements below/above
  5116 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5117 
  5118 * HOL: theorems impI, allI, ballI bound as "strip";
  5119 
  5120 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5121 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5122 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5123 
  5124 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5125 
  5126 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5127 main HOL, but was unused);
  5128 
  5129 * HOL: fewer consts declared as global (e.g. have to refer to
  5130 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5131 
  5132 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5133 in case of overlap with user translations (e.g. judgements over
  5134 tuples); (note that the underlying logical represenation is still
  5135 bogus);
  5136 
  5137 
  5138 *** ZF ***
  5139 
  5140 * ZF: simplification automatically cancels common terms in arithmetic
  5141 expressions over nat and int;
  5142 
  5143 * ZF: new treatment of nat to minimize type-checking: all operators
  5144 coerce their operands to a natural number using the function natify,
  5145 making the algebraic laws unconditional;
  5146 
  5147 * ZF: as above, for int: operators coerce their operands to an integer
  5148 using the function intify;
  5149 
  5150 * ZF: the integer library now contains many of the usual laws for the
  5151 orderings, including $<=, and monotonicity laws for $+ and $*;
  5152 
  5153 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5154 simplification;
  5155 
  5156 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5157 to the simplifier and classical reasoner simultaneously;
  5158 
  5159 
  5160 *** General ***
  5161 
  5162 * Provers: blast_tac now handles actual object-logic rules as
  5163 assumptions; note that auto_tac uses blast_tac internally as well;
  5164 
  5165 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5166 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5167 
  5168 * Provers: delrules now handles destruct rules as well (no longer need
  5169 explicit make_elim);
  5170 
  5171 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5172   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5173 use instead the strong form,
  5174   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5175 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5176 from destruct-rules;
  5177 
  5178 * Provers: Simplifier.easy_setup provides a fast path to basic
  5179 Simplifier setup for new object-logics;
  5180 
  5181 * Pure: AST translation rules no longer require constant head on LHS;
  5182 
  5183 * Pure: improved name spaces: ambiguous output is qualified; support
  5184 for hiding of names;
  5185 
  5186 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5187 XSYMBOL_HOME; no longer need to do manual configuration in most
  5188 situations;
  5189 
  5190 * system: compression of ML heaps images may now be controlled via -c
  5191 option of isabelle and isatool usedir (currently only observed by
  5192 Poly/ML);
  5193 
  5194 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5195 useful for remote X11);
  5196 
  5197 * system: provide TAGS file for Isabelle sources;
  5198 
  5199 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5200 order;
  5201 
  5202 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5203 timing flag supersedes proof_timing and Toplevel.trace;
  5204 
  5205 * ML: new combinators |>> and |>>> for incremental transformations
  5206 with secondary results (e.g. certain theory extensions):
  5207 
  5208 * ML: PureThy.add_defs gets additional argument to indicate potential
  5209 overloading (usually false);
  5210 
  5211 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5212 results;
  5213 
  5214 
  5215 
  5216 New in Isabelle99 (October 1999)
  5217 --------------------------------
  5218 
  5219 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5220 
  5221 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5222 are no longer simplified.  (This allows the simplifier to unfold recursive
  5223 functional programs.)  To restore the old behaviour, declare
  5224 
  5225     Delcongs [if_weak_cong];
  5226 
  5227 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5228 complement;
  5229 
  5230 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5231 
  5232 * HOL/datatype: mutual_induct_tac no longer exists --
  5233   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5234 
  5235 * HOL/typedef: fixed type inference for representing set; type
  5236 arguments now have to occur explicitly on the rhs as type constraints;
  5237 
  5238 * ZF: The con_defs part of an inductive definition may no longer refer
  5239 to constants declared in the same theory;
  5240 
  5241 * HOL, ZF: the function mk_cases, generated by the inductive
  5242 definition package, has lost an argument.  To simplify its result, it
  5243 uses the default simpset instead of a supplied list of theorems.
  5244 
  5245 * HOL/List: the constructors of type list are now Nil and Cons;
  5246 
  5247 * Simplifier: the type of the infix ML functions
  5248         setSSolver addSSolver setSolver addSolver
  5249 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5250 for packaging solvers. A solver is created via
  5251         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5252 where the string argument is only a comment.
  5253 
  5254 
  5255 *** Proof tools ***
  5256 
  5257 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5258 decision procedure for linear arithmetic. Currently it is used for
  5259 types `nat', `int', and `real' in HOL (see below); it can, should and
  5260 will be instantiated for other types and logics as well.
  5261 
  5262 * The simplifier now accepts rewrite rules with flexible heads, eg
  5263      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5264   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5265   matching.
  5266 
  5267 
  5268 *** General ***
  5269 
  5270 * New Isabelle/Isar subsystem provides an alternative to traditional
  5271 tactical theorem proving; together with the ProofGeneral/isar user
  5272 interface it offers an interactive environment for developing human
  5273 readable proof documents (Isar == Intelligible semi-automated
  5274 reasoning); for further information see isatool doc isar-ref,
  5275 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5276 
  5277 * improved and simplified presentation of theories: better HTML markup
  5278 (including colors), graph views in several sizes; isatool usedir now
  5279 provides a proper interface for user theories (via -P option); actual
  5280 document preparation based on (PDF)LaTeX is available as well (for
  5281 new-style theories only); see isatool doc system for more information;
  5282 
  5283 * native support for Proof General, both for classic Isabelle and
  5284 Isabelle/Isar;
  5285 
  5286 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5287 using the graph browser tool;
  5288 
  5289 * Isabelle manuals now also available as PDF;
  5290 
  5291 * theory loader rewritten from scratch (may not be fully
  5292 bug-compatible); old loadpath variable has been replaced by show_path,
  5293 add_path, del_path, reset_path functions; new operations such as
  5294 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5295 isatool doc ref);
  5296 
  5297 * improved isatool install: option -k creates KDE application icon,
  5298 option -p DIR installs standalone binaries;
  5299 
  5300 * added ML_PLATFORM setting (useful for cross-platform installations);
  5301 more robust handling of platform specific ML images for SML/NJ;
  5302 
  5303 * the settings environment is now statically scoped, i.e. it is never
  5304 created again in sub-processes invoked from isabelle, isatool, or
  5305 Isabelle;
  5306 
  5307 * path element specification '~~' refers to '$ISABELLE_HOME';
  5308 
  5309 * in locales, the "assumes" and "defines" parts may be omitted if
  5310 empty;
  5311 
  5312 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5313 long arrows);
  5314 
  5315 * new print_mode "HTML";
  5316 
  5317 * new flag show_tags controls display of tags of theorems (which are
  5318 basically just comments that may be attached by some tools);
  5319 
  5320 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5321 mode and goal output format:
  5322 
  5323 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5324 244c244
  5325 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5326 ---
  5327 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5328 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5329 181c181
  5330 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5331 ---
  5332 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5333 
  5334 * function bind_thms stores lists of theorems (cf. bind_thm);
  5335 
  5336 * new shorthand tactics ftac, eatac, datac, fatac;
  5337 
  5338 * qed (and friends) now accept "" as result name; in that case the
  5339 theorem is not stored, but proper checks and presentation of the
  5340 result still apply;
  5341 
  5342 * theorem database now also indexes constants "Trueprop", "all",
  5343 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5344 
  5345 
  5346 *** HOL ***
  5347 
  5348 ** HOL arithmetic **
  5349 
  5350 * There are now decision procedures for linear arithmetic over nat and
  5351 int:
  5352 
  5353 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5354 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5355 are treated as atomic; subformulae not involving type `nat' or `int'
  5356 are ignored; quantified subformulae are ignored unless they are
  5357 positive universal or negative existential. The tactic has to be
  5358 invoked by hand and can be a little bit slow. In particular, the
  5359 running time is exponential in the number of occurrences of `min' and
  5360 `max', and `-' on `nat'.
  5361 
  5362 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5363 (negated) (in)equalities among the premises and the conclusion into
  5364 account (i.e. no compound formulae) and does not know about `min' and
  5365 `max', and `-' on `nat'. It is fast and is used automatically by the
  5366 simplifier.
  5367 
  5368 NB: At the moment, these decision procedures do not cope with mixed
  5369 nat/int formulae where the two parts interact, such as `m < n ==>
  5370 int(m) < int(n)'.
  5371 
  5372 * HOL/Numeral provides a generic theory of numerals (encoded
  5373 efficiently as bit strings); setup for types nat/int/real is in place;
  5374 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5375 int, existing theories and proof scripts may require a few additional
  5376 type constraints;
  5377 
  5378 * integer division and remainder can now be performed on constant
  5379 arguments;
  5380 
  5381 * many properties of integer multiplication, division and remainder
  5382 are now available;
  5383 
  5384 * An interface to the Stanford Validity Checker (SVC) is available through the
  5385 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5386 are proved automatically.  SVC must be installed separately, and its results
  5387 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5388 invocation of the underlying oracle).  For SVC see
  5389   http://verify.stanford.edu/SVC
  5390 
  5391 * IsaMakefile: the HOL-Real target now builds an actual image;
  5392 
  5393 
  5394 ** HOL misc **
  5395 
  5396 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5397 (in Isabelle/Isar) -- by Gertrud Bauer;
  5398 
  5399 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5400 analysis for assembly languages with subtypes;
  5401 
  5402 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5403 -- avoids syntactic ambiguities and treats state, transition, and
  5404 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5405 changed syntax and (many) tactics;
  5406 
  5407 * HOL/inductive: Now also handles more general introduction rules such
  5408   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5409   theorems are now maintained within the theory (maintained via the
  5410   "mono" attribute);
  5411 
  5412 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5413   (using function types) such as
  5414 
  5415   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5416 
  5417 * HOL/record: record_simproc (part of the default simpset) takes care
  5418 of selectors applied to updated records; record_split_tac is no longer
  5419 part of the default claset; update_defs may now be removed from the
  5420 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5421 
  5422   claset_ref () := claset() addSWrapper record_split_wrapper;
  5423   Delsimprocs [record_simproc]
  5424 
  5425 * HOL/typedef: fixed type inference for representing set; type
  5426 arguments now have to occur explicitly on the rhs as type constraints;
  5427 
  5428 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5429 names rather than an ML expression;
  5430 
  5431 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5432 supplied later.  Program schemes can be defined, such as
  5433     "While B C s = (if B s then While B C (C s) else s)"
  5434 where the well-founded relation can be chosen after B and C have been given.
  5435 
  5436 * HOL/List: the constructors of type list are now Nil and Cons;
  5437 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5438 course, ML tools referring to List.list.op # etc. have to be adapted;
  5439 
  5440 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5441 disabled by default; run isabelle with option -m HOL to get back to
  5442 the original Gordon/HOL-style output;
  5443 
  5444 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5445 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5446 
  5447 * HOL basic syntax simplified (more orthogonal): all variants of
  5448 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5449 Eps operator is provided as well: "SOME x. P[x]";
  5450 
  5451 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5452 
  5453 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5454 thus available for user theories;
  5455 
  5456 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5457 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5458 time;
  5459 
  5460 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5461 several times and then mp;
  5462 
  5463 
  5464 *** LK ***
  5465 
  5466 * the notation <<...>> is now available as a notation for sequences of
  5467 formulas;
  5468 
  5469 * the simplifier is now installed
  5470 
  5471 * the axiom system has been generalized (thanks to Soren Heilmann)
  5472 
  5473 * the classical reasoner now has a default rule database
  5474 
  5475 
  5476 *** ZF ***
  5477 
  5478 * new primrec section allows primitive recursive functions to be given
  5479 directly (as in HOL) over datatypes and the natural numbers;
  5480 
  5481 * new tactics induct_tac and exhaust_tac for induction (or case
  5482 analysis) over datatypes and the natural numbers;
  5483 
  5484 * the datatype declaration of type T now defines the recursor T_rec;
  5485 
  5486 * simplification automatically does freeness reasoning for datatype
  5487 constructors;
  5488 
  5489 * automatic type-inference, with AddTCs command to insert new
  5490 type-checking rules;
  5491 
  5492 * datatype introduction rules are now added as Safe Introduction rules
  5493 to the claset;
  5494 
  5495 * the syntax "if P then x else y" is now available in addition to
  5496 if(P,x,y);
  5497 
  5498 
  5499 *** Internal programming interfaces ***
  5500 
  5501 * tuned simplifier trace output; new flag debug_simp;
  5502 
  5503 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5504 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5505 
  5506 * AxClass.axclass_tac lost the theory argument;
  5507 
  5508 * tuned current_goals_markers semantics: begin / end goal avoids
  5509 printing empty lines;
  5510 
  5511 * removed prs and prs_fn hook, which was broken because it did not
  5512 include \n in its semantics, forcing writeln to add one
  5513 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5514 string -> unit if you really want to output text without newline;
  5515 
  5516 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5517 plain output, interface builders may have to enable 'isabelle_font'
  5518 mode to get Isabelle font glyphs as before;
  5519 
  5520 * refined token_translation interface; INCOMPATIBILITY: output length
  5521 now of type real instead of int;
  5522 
  5523 * theory loader actions may be traced via new ThyInfo.add_hook
  5524 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5525 your own database of information attached to *whole* theories -- as
  5526 opposed to intra-theory data slots offered via TheoryDataFun;
  5527 
  5528 * proper handling of dangling sort hypotheses (at last!);
  5529 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5530 extra sort hypotheses that can be witnessed from the type signature;
  5531 the force_strip_shyps flag is gone, any remaining shyps are simply
  5532 left in the theorem (with a warning issued by strip_shyps_warning);
  5533 
  5534 
  5535 
  5536 New in Isabelle98-1 (October 1998)
  5537 ----------------------------------
  5538 
  5539 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5540 
  5541 * several changes of automated proof tools;
  5542 
  5543 * HOL: major changes to the inductive and datatype packages, including
  5544 some minor incompatibilities of theory syntax;
  5545 
  5546 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5547 called `inj_on';
  5548 
  5549 * HOL: removed duplicate thms in Arith:
  5550   less_imp_add_less  should be replaced by  trans_less_add1
  5551   le_imp_add_le      should be replaced by  trans_le_add1
  5552 
  5553 * HOL: unary minus is now overloaded (new type constraints may be
  5554 required);
  5555 
  5556 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5557 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5558 now taken as an integer constant.
  5559 
  5560 * Pure: ML function 'theory_of' renamed to 'theory';
  5561 
  5562 
  5563 *** Proof tools ***
  5564 
  5565 * Simplifier:
  5566   1. Asm_full_simp_tac is now more aggressive.
  5567      1. It will sometimes reorient premises if that increases their power to
  5568         simplify.
  5569      2. It does no longer proceed strictly from left to right but may also
  5570         rotate premises to achieve further simplification.
  5571      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5572      old Asm_full_simp_tac in that it does not rotate premises.
  5573   2. The simplifier now knows a little bit about nat-arithmetic.
  5574 
  5575 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5576 allows for selected deletion of wrappers, by introduction of names for
  5577 wrapper functionals.  This implies that addbefore, addSbefore,
  5578 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5579 and that adding two tactics with the same name overwrites the first
  5580 one (emitting a warning).
  5581   type wrapper = (int -> tactic) -> (int -> tactic)
  5582   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5583   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5584   delWrapper, delSWrapper: claset *  string            -> claset
  5585   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5586 
  5587 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5588 semantics; addbefore now affects only the unsafe part of step_tac
  5589 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5590 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5591 by Force_tac;
  5592 
  5593 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5594 compWrapper; added safe wrapper (and access functions for it);
  5595 
  5596 * HOL/split_all_tac is now much faster and fails if there is nothing
  5597 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5598 and the names of the automatically generated variables have changed.
  5599 split_all_tac has moved within claset() from unsafe wrappers to safe
  5600 wrappers, which means that !!-bound variables are split much more
  5601 aggressively, and safe_tac and clarify_tac now split such variables.
  5602 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5603 Note: the same holds for record_split_tac, which does the job of
  5604 split_all_tac for record fields.
  5605 
  5606 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5607 permanently to the default simpset using Addsplits just like
  5608 Addsimps. They can be removed via Delsplits just like
  5609 Delsimps. Lower-case versions are also available.
  5610 
  5611 * HOL/Simplifier: The rule split_if is now part of the default
  5612 simpset. This means that the simplifier will eliminate all occurrences
  5613 of if-then-else in the conclusion of a goal. To prevent this, you can
  5614 either remove split_if completely from the default simpset by
  5615 `Delsplits [split_if]' or remove it in a specific call of the
  5616 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5617 other case splitting rules to/from the default simpset: every datatype
  5618 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5619 t is the name of the datatype).
  5620 
  5621 * Classical reasoner / Simplifier combination: new force_tac (and
  5622 derivatives Force_tac, force) combines rewriting and classical
  5623 reasoning (and whatever other tools) similarly to auto_tac, but is
  5624 aimed to solve the given subgoal completely.
  5625 
  5626 
  5627 *** General ***
  5628 
  5629 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5630 and `goalw': the theory is no longer needed as an explicit argument -
  5631 the current theory context is used; assumptions are no longer returned
  5632 at the ML-level unless one of them starts with ==> or !!; it is
  5633 recommended to convert to these new commands using isatool fixgoal
  5634 (backup your sources first!);
  5635 
  5636 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5637 the current theory context, and 'theory' to lookup stored theories;
  5638 
  5639 * new theory section 'locale' for declaring constants, assumptions and
  5640 definitions that have local scope;
  5641 
  5642 * new theory section 'nonterminals' for purely syntactic types;
  5643 
  5644 * new theory section 'setup' for generic ML setup functions
  5645 (e.g. package initialization);
  5646 
  5647 * the distribution now includes Isabelle icons: see
  5648 lib/logo/isabelle-{small,tiny}.xpm;
  5649 
  5650 * isatool install - install binaries with absolute references to
  5651 ISABELLE_HOME/bin;
  5652 
  5653 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5654 
  5655 * print mode 'emacs' reserved for Isamode;
  5656 
  5657 * support multiple print (ast) translations per constant name;
  5658 
  5659 * theorems involving oracles are now printed with a suffixed [!];
  5660 
  5661 
  5662 *** HOL ***
  5663 
  5664 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5665 
  5666 * HOL/inductive package reorganized and improved: now supports mutual
  5667 definitions such as
  5668 
  5669   inductive EVEN ODD
  5670     intrs
  5671       null "0 : EVEN"
  5672       oddI "n : EVEN ==> Suc n : ODD"
  5673       evenI "n : ODD ==> Suc n : EVEN"
  5674 
  5675 new theorem list "elims" contains an elimination rule for each of the
  5676 recursive sets; inductive definitions now handle disjunctive premises
  5677 correctly (also ZF);
  5678 
  5679 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5680 "mutual_induct" no longer exists - the induction rule is always
  5681 contained in "induct";
  5682 
  5683 
  5684 * HOL/datatype package re-implemented and greatly improved: now
  5685 supports mutually recursive datatypes such as
  5686 
  5687   datatype
  5688     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5689             | SUM ('a aexp) ('a aexp)
  5690             | DIFF ('a aexp) ('a aexp)
  5691             | NUM 'a
  5692   and
  5693     'a bexp = LESS ('a aexp) ('a aexp)
  5694             | AND ('a bexp) ('a bexp)
  5695             | OR ('a bexp) ('a bexp)
  5696 
  5697 as well as indirectly recursive datatypes such as
  5698 
  5699   datatype
  5700     ('a, 'b) term = Var 'a
  5701                   | App 'b ((('a, 'b) term) list)
  5702 
  5703 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5704 induction on mutually / indirectly recursive datatypes.
  5705 
  5706 Primrec equations are now stored in theory and can be accessed via
  5707 <function_name>.simps.
  5708 
  5709 INCOMPATIBILITIES:
  5710 
  5711   - Theories using datatypes must now have theory Datatype as an
  5712     ancestor.
  5713   - The specific <typename>.induct_tac no longer exists - use the
  5714     generic induct_tac instead.
  5715   - natE has been renamed to nat.exhaust - use exhaust_tac
  5716     instead of res_inst_tac ... natE. Note that the variable
  5717     names in nat.exhaust differ from the names in natE, this
  5718     may cause some "fragile" proofs to fail.
  5719   - The theorems split_<typename>_case and split_<typename>_case_asm
  5720     have been renamed to <typename>.split and <typename>.split_asm.
  5721   - Since default sorts of type variables are now handled correctly,
  5722     some datatype definitions may have to be annotated with explicit
  5723     sort constraints.
  5724   - Primrec definitions no longer require function name and type
  5725     of recursive argument.
  5726 
  5727 Consider using isatool fixdatatype to adapt your theories and proof
  5728 scripts to the new package (backup your sources first!).
  5729 
  5730 
  5731 * HOL/record package: considerably improved implementation; now
  5732 includes concrete syntax for record types, terms, updates; theorems
  5733 for surjective pairing and splitting !!-bound record variables; proof
  5734 support is as follows:
  5735 
  5736   1) standard conversions (selectors or updates applied to record
  5737 constructor terms) are part of the standard simpset;
  5738 
  5739   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5740 made part of standard simpset and claset via addIffs;
  5741 
  5742   3) a tactic for record field splitting (record_split_tac) is part of
  5743 the standard claset (addSWrapper);
  5744 
  5745 To get a better idea about these rules you may retrieve them via
  5746 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5747 the name of your record type.
  5748 
  5749 The split tactic 3) conceptually simplifies by the following rule:
  5750 
  5751   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5752 
  5753 Thus any record variable that is bound by meta-all will automatically
  5754 blow up into some record constructor term, consequently the
  5755 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5756 solve record problems automatically.
  5757 
  5758 
  5759 * reorganized the main HOL image: HOL/Integ and String loaded by
  5760 default; theory Main includes everything;
  5761 
  5762 * automatic simplification of integer sums and comparisons, using cancellation;
  5763 
  5764 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5765 
  5766 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5767 
  5768 * many new identities for unions, intersections, set difference, etc.;
  5769 
  5770 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5771 called split_if, split_split, split_sum_case and split_nat_case (to go
  5772 with add/delsplits);
  5773 
  5774 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5775 (?x::unit) = (); this is made part of the default simpset, which COULD
  5776 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5777 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5778 unit_abs_eta_conv is added in order to counter the effect of
  5779 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5780 %u.f();
  5781 
  5782 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5783 makes more sense);
  5784 
  5785 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5786   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5787   disjointness reasoning but breaking a few old proofs.
  5788 
  5789 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5790 to 'converse' from 'inverse' (for compatibility with ZF and some
  5791 literature);
  5792 
  5793 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5794 the well-founded relation;
  5795 
  5796 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5797     Compl A.  The "Compl" syntax remains available as input syntax for this
  5798     release ONLY.
  5799 
  5800 * HOL/Update: new theory of function updates:
  5801     f(a:=b) == %x. if x=a then b else f x
  5802 may also be iterated as in f(a:=b,c:=d,...);
  5803 
  5804 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5805 
  5806 * HOL/List:
  5807   - new function list_update written xs[i:=v] that updates the i-th
  5808     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5809   - new function `upt' written [i..j(] which generates the list
  5810     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5811     bound write [i..j], which is a shorthand for [i..j+1(].
  5812   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5813 
  5814 * HOL/Arith:
  5815   - removed 'pred' (predecessor) function;
  5816   - generalized some theorems about n-1;
  5817   - many new laws about "div" and "mod";
  5818   - new laws about greatest common divisors (see theory ex/Primes);
  5819 
  5820 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5821 instead of "inverse";
  5822 
  5823 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5824   of the multiset ordering;
  5825 
  5826 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5827   (not included by default);
  5828 
  5829 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5830 
  5831 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5832   programs, i.e. different program variables may have different types.
  5833 
  5834 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5835   [previously, this check worked only if the rewrite rule was unconditional]
  5836   Now rew can involve either definitions or equalities (either == or =).
  5837 
  5838 
  5839 *** ZF ***
  5840 
  5841 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5842   only the theorems proved on ZF.ML;
  5843 
  5844 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5845   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5846   disjointness reasoning but breaking a few old proofs.
  5847 
  5848 * ZF/Update: new theory of function updates
  5849     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5850   may also be iterated as in f(a:=b,c:=d,...);
  5851 
  5852 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5853 
  5854 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5855   [previously, this check worked only if the rewrite rule was unconditional]
  5856   Now rew can involve either definitions or equalities (either == or =).
  5857 
  5858 * case_tac provided for compatibility with HOL
  5859     (like the old excluded_middle_tac, but with subgoals swapped)
  5860 
  5861 
  5862 *** Internal programming interfaces ***
  5863 
  5864 * Pure: several new basic modules made available for general use, see
  5865 also src/Pure/README;
  5866 
  5867 * improved the theory data mechanism to support encapsulation (data
  5868 kind name replaced by private Object.kind, acting as authorization
  5869 key); new type-safe user interface via functor TheoryDataFun; generic
  5870 print_data function becomes basically useless;
  5871 
  5872 * removed global_names compatibility flag -- all theory declarations
  5873 are qualified by default;
  5874 
  5875 * module Pure/Syntax now offers quote / antiquote translation
  5876 functions (useful for Hoare logic etc. with implicit dependencies);
  5877 see HOL/ex/Antiquote for an example use;
  5878 
  5879 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5880 cterm -> thm;
  5881 
  5882 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5883 subgoal;
  5884 
  5885 * Display.print_goals function moved to Locale.print_goals;
  5886 
  5887 * standard print function for goals supports current_goals_markers
  5888 variable for marking begin of proof, end of proof, start of goal; the
  5889 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5890 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5891 for example;
  5892 
  5893 
  5894 
  5895 New in Isabelle98 (January 1998)
  5896 --------------------------------
  5897 
  5898 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5899 
  5900 * changed lexical syntax of terms / types: dots made part of long
  5901 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5902 
  5903 * simpset (and claset) reference variable replaced by functions
  5904 simpset / simpset_ref;
  5905 
  5906 * no longer supports theory aliases (via merge) and non-trivial
  5907 implicit merge of thms' signatures;
  5908 
  5909 * most internal names of constants changed due to qualified names;
  5910 
  5911 * changed Pure/Sequence interface (see Pure/seq.ML);
  5912 
  5913 
  5914 *** General Changes ***
  5915 
  5916 * hierachically structured name spaces (for consts, types, axms, thms
  5917 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5918 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5919 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5920 long_names for fully qualified output names; NOTE: ML programs
  5921 (special tactics, packages etc.) referring to internal names may have
  5922 to be adapted to cope with fully qualified names; in case of severe
  5923 backward campatibility problems try setting 'global_names' at compile
  5924 time to have enrything declared within a flat name space; one may also
  5925 fine tune name declarations in theories via the 'global' and 'local'
  5926 section;
  5927 
  5928 * reimplemented the implicit simpset and claset using the new anytype
  5929 data filed in signatures; references simpset:simpset ref etc. are
  5930 replaced by functions simpset:unit->simpset and
  5931 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5932 to patch your ML files accordingly;
  5933 
  5934 * HTML output now includes theory graph data for display with Java
  5935 applet or isatool browser; data generated automatically via isatool
  5936 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5937 
  5938 * defs may now be conditional; improved rewrite_goals_tac to handle
  5939 conditional equations;
  5940 
  5941 * defs now admits additional type arguments, using TYPE('a) syntax;
  5942 
  5943 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5944 creates a new theory node; implicit merge of thms' signatures is
  5945 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5946 transfer:theory->thm->thm in (rare) cases;
  5947 
  5948 * improved handling of draft signatures / theories; draft thms (and
  5949 ctyps, cterms) are automatically promoted to real ones;
  5950 
  5951 * slightly changed interfaces for oracles: admit many per theory, named
  5952 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5953 
  5954 * print_goals: optional output of const types (set show_consts and
  5955 show_types);
  5956 
  5957 * improved output of warnings (###) and errors (***);
  5958 
  5959 * subgoal_tac displays a warning if the new subgoal has type variables;
  5960 
  5961 * removed old README and Makefiles;
  5962 
  5963 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5964 
  5965 * removed obsolete init_pps and init_database;
  5966 
  5967 * deleted the obsolete tactical STATE, which was declared by
  5968     fun STATE tacfun st = tacfun st st;
  5969 
  5970 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5971 (which abbreviates $HOME);
  5972 
  5973 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5974 use isatool fixseq to adapt your ML programs (this works for fully
  5975 qualified references to the Sequence structure only!);
  5976 
  5977 * use_thy no longer requires writable current directory; it always
  5978 reloads .ML *and* .thy file, if either one is out of date;
  5979 
  5980 
  5981 *** Classical Reasoner ***
  5982 
  5983 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5984 tactics that use classical reasoning to simplify a subgoal without
  5985 splitting it into several subgoals;
  5986 
  5987 * Safe_tac: like safe_tac but uses the default claset;
  5988 
  5989 
  5990 *** Simplifier ***
  5991 
  5992 * added simplification meta rules:
  5993     (asm_)(full_)simplify: simpset -> thm -> thm;
  5994 
  5995 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5996 logics (again);
  5997 
  5998 * added prems argument to simplification procedures;
  5999 
  6000 * HOL, FOL, ZF: added infix function `addsplits':
  6001   instead of `<simpset> setloop (split_tac <thms>)'
  6002   you can simply write `<simpset> addsplits <thms>'
  6003 
  6004 
  6005 *** Syntax ***
  6006 
  6007 * TYPE('a) syntax for type reflection terms;
  6008 
  6009 * no longer handles consts with name "" -- declare as 'syntax' instead;
  6010 
  6011 * pretty printer: changed order of mixfix annotation preference (again!);
  6012 
  6013 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  6014 
  6015 
  6016 *** HOL ***
  6017 
  6018 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6019   with `addloop' of the simplifier to faciliate case splitting in premises.
  6020 
  6021 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  6022 
  6023 * HOL/Auth: new protocol proofs including some for the Internet
  6024   protocol TLS;
  6025 
  6026 * HOL/Map: new theory of `maps' a la VDM;
  6027 
  6028 * HOL/simplifier: simplification procedures nat_cancel_sums for
  6029 cancelling out common nat summands from =, <, <= (in)equalities, or
  6030 differences; simplification procedures nat_cancel_factor for
  6031 cancelling common factor from =, <, <= (in)equalities over natural
  6032 sums; nat_cancel contains both kinds of procedures, it is installed by
  6033 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  6034 
  6035 * HOL/simplifier: terms of the form
  6036   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  6037   are rewritten to
  6038   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  6039   and those of the form
  6040   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  6041   are rewritten to
  6042   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  6043 
  6044 * HOL/datatype
  6045   Each datatype `t' now comes with a theorem `split_t_case' of the form
  6046 
  6047   P(t_case f1 ... fn x) =
  6048      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  6049         ...
  6050        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  6051      )
  6052 
  6053   and a theorem `split_t_case_asm' of the form
  6054 
  6055   P(t_case f1 ... fn x) =
  6056     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  6057         ...
  6058        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  6059      )
  6060   which can be added to a simpset via `addsplits'. The existing theorems
  6061   expand_list_case and expand_option_case have been renamed to
  6062   split_list_case and split_option_case.
  6063 
  6064 * HOL/Arithmetic:
  6065   - `pred n' is automatically converted to `n-1'.
  6066     Users are strongly encouraged not to use `pred' any longer,
  6067     because it will disappear altogether at some point.
  6068   - Users are strongly encouraged to write "0 < n" rather than
  6069     "n ~= 0". Theorems and proof tools have been modified towards this
  6070     `standard'.
  6071 
  6072 * HOL/Lists:
  6073   the function "set_of_list" has been renamed "set" (and its theorems too);
  6074   the function "nth" now takes its arguments in the reverse order and
  6075   has acquired the infix notation "!" as in "xs!n".
  6076 
  6077 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  6078 
  6079 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  6080   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  6081 
  6082 * HOL/record: extensible records with schematic structural subtyping
  6083 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  6084 still lacks various theorems and concrete record syntax;
  6085 
  6086 
  6087 *** HOLCF ***
  6088 
  6089 * removed "axioms" and "generated by" sections;
  6090 
  6091 * replaced "ops" section by extended "consts" section, which is capable of
  6092   handling the continuous function space "->" directly;
  6093 
  6094 * domain package:
  6095   . proves theorems immediately and stores them in the theory,
  6096   . creates hierachical name space,
  6097   . now uses normal mixfix annotations (instead of cinfix...),
  6098   . minor changes to some names and values (for consistency),
  6099   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  6100   . separator between mutual domain defs: changed "," to "and",
  6101   . improved handling of sort constraints;  now they have to
  6102     appear on the left-hand side of the equations only;
  6103 
  6104 * fixed LAM <x,y,zs>.b syntax;
  6105 
  6106 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  6107 adm (%x. P (t x)), where P is chainfinite and t continuous;
  6108 
  6109 
  6110 *** FOL and ZF ***
  6111 
  6112 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6113   with `addloop' of the simplifier to faciliate case splitting in premises.
  6114 
  6115 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6116 in HOL, they strip ALL and --> from proved theorems;
  6117 
  6118 
  6119 
  6120 New in Isabelle94-8 (May 1997)
  6121 ------------------------------
  6122 
  6123 *** General Changes ***
  6124 
  6125 * new utilities to build / run / maintain Isabelle etc. (in parts
  6126 still somewhat experimental); old Makefiles etc. still functional;
  6127 
  6128 * new 'Isabelle System Manual';
  6129 
  6130 * INSTALL text, together with ./configure and ./build scripts;
  6131 
  6132 * reimplemented type inference for greater efficiency, better error
  6133 messages and clean internal interface;
  6134 
  6135 * prlim command for dealing with lots of subgoals (an easier way of
  6136 setting goals_limit);
  6137 
  6138 
  6139 *** Syntax ***
  6140 
  6141 * supports alternative (named) syntax tables (parser and pretty
  6142 printer); internal interface is provided by add_modesyntax(_i);
  6143 
  6144 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6145 be used in conjunction with the Isabelle symbol font; uses the
  6146 "symbols" syntax table;
  6147 
  6148 * added token_translation interface (may translate name tokens in
  6149 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6150 the current print_mode); IMPORTANT: user print translation functions
  6151 are responsible for marking newly introduced bounds
  6152 (Syntax.mark_boundT);
  6153 
  6154 * token translations for modes "xterm" and "xterm_color" that display
  6155 names in bold, underline etc. or colors (which requires a color
  6156 version of xterm);
  6157 
  6158 * infixes may now be declared with names independent of their syntax;
  6159 
  6160 * added typed_print_translation (like print_translation, but may
  6161 access type of constant);
  6162 
  6163 
  6164 *** Classical Reasoner ***
  6165 
  6166 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6167 some limitations.  Blast_tac...
  6168   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6169   + ignores elimination rules that don't have the correct format
  6170         (the conclusion MUST be a formula variable)
  6171   + ignores types, which can make HOL proofs fail
  6172   + rules must not require higher-order unification, e.g. apply_type in ZF
  6173     [message "Function Var's argument not a bound variable" relates to this]
  6174   + its proof strategy is more general but can actually be slower
  6175 
  6176 * substitution with equality assumptions no longer permutes other
  6177 assumptions;
  6178 
  6179 * minor changes in semantics of addafter (now called addaltern); renamed
  6180 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6181 (and access functions for it);
  6182 
  6183 * improved combination of classical reasoner and simplifier:
  6184   + functions for handling clasimpsets
  6185   + improvement of addss: now the simplifier is called _after_ the
  6186     safe steps.
  6187   + safe variant of addss called addSss: uses safe simplifications
  6188     _during_ the safe steps. It is more complete as it allows multiple
  6189     instantiations of unknowns (e.g. with slow_tac).
  6190 
  6191 *** Simplifier ***
  6192 
  6193 * added interface for simplification procedures (functions that
  6194 produce *proven* rewrite rules on the fly, depending on current
  6195 redex);
  6196 
  6197 * ordering on terms as parameter (used for ordered rewriting);
  6198 
  6199 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6200 
  6201 * the solver is now split into a safe and an unsafe part.
  6202 This should be invisible for the normal user, except that the
  6203 functions setsolver and addsolver have been renamed to setSolver and
  6204 addSolver; added safe_asm_full_simp_tac;
  6205 
  6206 
  6207 *** HOL ***
  6208 
  6209 * a generic induction tactic `induct_tac' which works for all datatypes and
  6210 also for type `nat';
  6211 
  6212 * a generic case distinction tactic `exhaust_tac' which works for all
  6213 datatypes and also for type `nat';
  6214 
  6215 * each datatype comes with a function `size';
  6216 
  6217 * patterns in case expressions allow tuple patterns as arguments to
  6218 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6219 
  6220 * primrec now also works with type nat;
  6221 
  6222 * recdef: a new declaration form, allows general recursive functions to be
  6223 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6224 
  6225 * the constant for negation has been renamed from "not" to "Not" to
  6226 harmonize with FOL, ZF, LK, etc.;
  6227 
  6228 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6229 infinite lists;
  6230 
  6231 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6232 
  6233 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6234 problems in commutative rings, using axiomatic type classes for + and *;
  6235 
  6236 * more examples in HOL/MiniML and HOL/Auth;
  6237 
  6238 * more default rewrite rules for quantifiers, union/intersection;
  6239 
  6240 * a new constant `arbitrary == @x.False';
  6241 
  6242 * HOLCF/IOA replaces old HOL/IOA;
  6243 
  6244 * HOLCF changes: derived all rules and arities
  6245   + axiomatic type classes instead of classes
  6246   + typedef instead of faking type definitions
  6247   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6248   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6249   + eliminated the types void, one, tr
  6250   + use unit lift and bool lift (with translations) instead of one and tr
  6251   + eliminated blift from Lift3.thy (use Def instead of blift)
  6252   all eliminated rules are derived as theorems --> no visible changes ;
  6253 
  6254 
  6255 *** ZF ***
  6256 
  6257 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6258 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back