NEWS
author wenzelm
Mon Jul 20 13:52:27 2009 +0200 (2009-07-20)
changeset 32079 5dc52b199815
parent 32066 091f1e304120
parent 32061 11f8ee55662d
child 32092 6a5995438266
child 32130 2a0645733185
child 32134 ee143615019c
permissions -rw-r--r--
merged
     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 
   124 *** System ***
   125 
   126 * Discontinued support for Poly/ML 4.x versions.
   127 
   128 * Removed "compress" option from isabelle-process and isabelle usedir;
   129 this is always enabled.
   130 
   131 * More fine-grained control of proof parallelism, cf.
   132 Goal.parallel_proofs in ML and usedir option -q LEVEL.
   133 
   134 
   135 
   136 New in Isabelle2009 (April 2009)
   137 --------------------------------
   138 
   139 *** General ***
   140 
   141 * Simplified main Isabelle executables, with less surprises on
   142 case-insensitive file-systems (such as Mac OS).
   143 
   144   - The main Isabelle tool wrapper is now called "isabelle" instead of
   145     "isatool."
   146 
   147   - The former "isabelle" alias for "isabelle-process" has been
   148     removed (should rarely occur to regular users).
   149 
   150   - The former "isabelle-interface" and its alias "Isabelle" have been
   151     removed (interfaces are now regular Isabelle tools).
   152 
   153 Within scripts and make files, the Isabelle environment variables
   154 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
   155 respectively.  (The latter are still available as legacy feature.)
   156 
   157 The old isabelle-interface wrapper could react in confusing ways if
   158 the interface was uninstalled or changed otherwise.  Individual
   159 interface tool configuration is now more explicit, see also the
   160 Isabelle system manual.  In particular, Proof General is now available
   161 via "isabelle emacs".
   162 
   163 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
   164 purge installed copies of Isabelle executables and re-run "isabelle
   165 install -p ...", or use symlinks.
   166 
   167 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
   168 old ~/isabelle, which was slightly non-standard and apt to cause
   169 surprises on case-insensitive file-systems (such as Mac OS).
   170 
   171 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
   172 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
   173 care is required when using older releases of Isabelle.  Note that
   174 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
   175 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
   176 
   177 * Proofs of fully specified statements are run in parallel on
   178 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
   179 a regular 4-core machine, if the initial heap space is made reasonably
   180 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
   181 
   182 * The main reference manuals ("isar-ref", "implementation", and
   183 "system") have been updated and extended.  Formally checked references
   184 as hyperlinks are now available uniformly.
   185 
   186 
   187 *** Pure ***
   188 
   189 * Complete re-implementation of locales.  INCOMPATIBILITY in several
   190 respects.  The most important changes are listed below.  See the
   191 Tutorial on Locales ("locales" manual) for details.
   192 
   193 - In locale expressions, instantiation replaces renaming.  Parameters
   194 must be declared in a for clause.  To aid compatibility with previous
   195 parameter inheritance, in locale declarations, parameters that are not
   196 'touched' (instantiation position "_" or omitted) are implicitly added
   197 with their syntax at the beginning of the for clause.
   198 
   199 - Syntax from abbreviations and definitions in locales is available in
   200 locale expressions and context elements.  The latter is particularly
   201 useful in locale declarations.
   202 
   203 - More flexible mechanisms to qualify names generated by locale
   204 expressions.  Qualifiers (prefixes) may be specified in locale
   205 expressions, and can be marked as mandatory (syntax: "name!:") or
   206 optional (syntax "name?:").  The default depends for plain "name:"
   207 depends on the situation where a locale expression is used: in
   208 commands 'locale' and 'sublocale' prefixes are optional, in
   209 'interpretation' and 'interpret' prefixes are mandatory.  The old
   210 implicit qualifiers derived from the parameter names of a locale are
   211 no longer generated.
   212 
   213 - Command "sublocale l < e" replaces "interpretation l < e".  The
   214 instantiation clause in "interpretation" and "interpret" (square
   215 brackets) is no longer available.  Use locale expressions.
   216 
   217 - When converting proof scripts, mandatory qualifiers in
   218 'interpretation' and 'interpret' should be retained by default, even
   219 if this is an INCOMPATIBILITY compared to former behavior.  In the
   220 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   221 in locale expressions range over a single locale instance only.
   222 
   223 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   224 In existing theorem specifications replace the includes element by the
   225 respective context elements of the included locale, omitting those
   226 that are already present in the theorem specification.  Multiple
   227 assume elements of a locale should be replaced by a single one
   228 involving the locale predicate.  In the proof body, declarations (most
   229 notably theorems) may be regained by interpreting the respective
   230 locales in the proof context as required (command "interpret").
   231 
   232 If using "includes" in replacement of a target solely because the
   233 parameter types in the theorem are not as general as in the target,
   234 consider declaring a new locale with additional type constraints on
   235 the parameters (context element "constrains").
   236 
   237 - Discontinued "locale (open)".  INCOMPATIBILITY.
   238 
   239 - Locale interpretation commands no longer attempt to simplify goal.
   240 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   241 methods intro_locales and unfold_locales to clarify.
   242 
   243 - Locale interpretation commands no longer accept interpretation
   244 attributes.  INCOMPATIBILITY.
   245 
   246 * Class declaration: so-called "base sort" must not be given in import
   247 list any longer, but is inferred from the specification.  Particularly
   248 in HOL, write
   249 
   250     class foo = ...
   251 
   252 instead of
   253 
   254     class foo = type + ...
   255 
   256 * Class target: global versions of theorems stemming do not carry a
   257 parameter prefix any longer.  INCOMPATIBILITY.
   258 
   259 * Class 'instance' command no longer accepts attached definitions.
   260 INCOMPATIBILITY, use proper 'instantiation' target instead.
   261 
   262 * Recovered hiding of consts, which was accidentally broken in
   263 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   264 makes c inaccessible; consider using ``hide (open) const c'' instead.
   265 
   266 * Slightly more coherent Pure syntax, with updated documentation in
   267 isar-ref manual.  Removed locales meta_term_syntax and
   268 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   269 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   270 directly in regular applications.
   271 
   272 * There is a new syntactic category "float_const" for signed decimal
   273 fractions (e.g. 123.45 or -123.45).
   274 
   275 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   276 interface with 'setup' command instead.
   277 
   278 * Command 'local_setup' is similar to 'setup', but operates on a local
   279 theory context.
   280 
   281 * The 'axiomatization' command now only works within a global theory
   282 context.  INCOMPATIBILITY.
   283 
   284 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   285 hypotheses.  Sorts required in the course of reasoning need to be
   286 covered by the constraints in the initial statement, completed by the
   287 type instance information of the background theory.  Non-trivial sort
   288 hypotheses, which rarely occur in practice, may be specified via
   289 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   290 
   291   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   292 
   293 The result contains an implicit sort hypotheses as before --
   294 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   295 normalization.
   296 
   297 * Generalized Isar history, with support for linear undo, direct state
   298 addressing etc.
   299 
   300 * Changed defaults for unify configuration options:
   301 
   302   unify_trace_bound = 50 (formerly 25)
   303   unify_search_bound = 60 (formerly 30)
   304 
   305 * Different bookkeeping for code equations (INCOMPATIBILITY):
   306 
   307   a) On theory merge, the last set of code equations for a particular
   308      constant is taken (in accordance with the policy applied by other
   309      parts of the code generator framework).
   310 
   311   b) Code equations stemming from explicit declarations (e.g. code
   312      attribute) gain priority over default code equations stemming
   313      from definition, primrec, fun etc.
   314 
   315 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   316 
   317 * Unified theorem tables for both code generators.  Thus [code
   318 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   319 
   320 * Command 'find_consts' searches for constants based on type and name
   321 patterns, e.g.
   322 
   323     find_consts "_ => bool"
   324 
   325 By default, matching is against subtypes, but it may be restricted to
   326 the whole type.  Searching by name is possible.  Multiple queries are
   327 conjunctive and queries may be negated by prefixing them with a
   328 hyphen:
   329 
   330     find_consts strict: "_ => bool" name: "Int" -"int => int"
   331 
   332 * New 'find_theorems' criterion "solves" matches theorems that
   333 directly solve the current goal (modulo higher-order unification).
   334 
   335 * Auto solve feature for main theorem statements: whenever a new goal
   336 is stated, "find_theorems solves" is called; any theorems that could
   337 solve the lemma directly are listed as part of the goal state.
   338 Cf. associated options in Proof General Isabelle settings menu,
   339 enabled by default, with reasonable timeout for pathological cases of
   340 higher-order unification.
   341 
   342 
   343 *** Document preparation ***
   344 
   345 * Antiquotation @{lemma} now imitates a regular terminal proof,
   346 demanding keyword 'by' and supporting the full method expression
   347 syntax just like the Isar command 'by'.
   348 
   349 
   350 *** HOL ***
   351 
   352 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   353 points Main and Complex_Main remain as before.
   354 
   355 * Logic image HOL-Plain provides a minimal HOL with the most important
   356 tools available (inductive, datatype, primrec, ...).  This facilitates
   357 experimentation and tool development.  Note that user applications
   358 (and library theories) should never refer to anything below theory
   359 Main, as before.
   360 
   361 * Logic image HOL-Main stops at theory Main, and thus facilitates
   362 experimentation due to shorter build times.
   363 
   364 * Logic image HOL-NSA contains theories of nonstandard analysis which
   365 were previously part of former HOL-Complex.  Entry point Hyperreal
   366 remains valid, but theories formerly using Complex_Main should now use
   367 new entry point Hypercomplex.
   368 
   369 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   370 Posix processes.  Avoids potentially expensive forking of the ML
   371 process.  New thread-based implementation also works on non-Unix
   372 platforms (Cygwin).  Provers are no longer hardwired, but defined
   373 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   374 commands are covered in the isar-ref manual.
   375 
   376 * Wrapper scripts for remote SystemOnTPTP service allows to use
   377 sledgehammer without local ATP installation (Vampire etc.). Other
   378 provers may be included via suitable ML wrappers, see also
   379 src/HOL/ATP_Linkup.thy.
   380 
   381 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   382 menu.
   383 
   384 * The metis method no longer fails because the theorem is too trivial
   385 (contains the empty clause).
   386 
   387 * The metis method now fails in the usual manner, rather than raising
   388 an exception, if it determines that it cannot prove the theorem.
   389 
   390 * Method "coherent" implements a prover for coherent logic (see also
   391 src/Tools/coherent.ML).
   392 
   393 * Constants "undefined" and "default" replace "arbitrary".  Usually
   394 "undefined" is the right choice to replace "arbitrary", though
   395 logically there is no difference.  INCOMPATIBILITY.
   396 
   397 * Command "value" now integrates different evaluation mechanisms.  The
   398 result of the first successful evaluation mechanism is printed.  In
   399 square brackets a particular named evaluation mechanisms may be
   400 specified (currently, [SML], [code] or [nbe]).  See further
   401 src/HOL/ex/Eval_Examples.thy.
   402 
   403 * Normalization by evaluation now allows non-leftlinear equations.
   404 Declare with attribute [code nbe].
   405 
   406 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   407 as the structured Isar versions "cases" and "induct", cf. the
   408 corresponding "cases" and "induct" attributes.  Mutual induction rules
   409 are now presented as a list of individual projections
   410 (e.g. foo_bar.inducts for types foo and bar); the old format with
   411 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   412 rare situations a different rule is selected --- notably nested tuple
   413 elimination instead of former prod.exhaust: use explicit (case_tac t
   414 rule: prod.exhaust) here.
   415 
   416 * Attributes "cases", "induct", "coinduct" support "del" option.
   417 
   418 * Removed fact "case_split_thm", which duplicates "case_split".
   419 
   420 * The option datatype has been moved to a new theory Option.  Renamed
   421 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   422 
   423 * New predicate "strict_mono" classifies strict functions on partial
   424 orders.  With strict functions on linear orders, reasoning about
   425 (in)equalities is facilitated by theorems "strict_mono_eq",
   426 "strict_mono_less_eq" and "strict_mono_less".
   427 
   428 * Some set operations are now proper qualified constants with
   429 authentic syntax.  INCOMPATIBILITY:
   430 
   431     op Int ~>   Set.Int
   432     op Un ~>    Set.Un
   433     INTER ~>    Set.INTER
   434     UNION ~>    Set.UNION
   435     Inter ~>    Set.Inter
   436     Union ~>    Set.Union
   437     {} ~>       Set.empty
   438     UNIV ~>     Set.UNIV
   439 
   440 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   441 theory Set.
   442 
   443 * Auxiliary class "itself" has disappeared -- classes without any
   444 parameter are treated as expected by the 'class' command.
   445 
   446 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   447 
   448 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   449 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   450 
   451 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   452 method "approximation".  It proves formulas on real values by using
   453 interval arithmetic.  In the formulas are also the transcendental
   454 functions sin, cos, tan, atan, ln, exp and the constant pi are
   455 allowed. For examples see
   456 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   457 
   458 * Theory "Reflection" now resides in HOL/Library.
   459 
   460 * Entry point to Word library now simply named "Word".
   461 INCOMPATIBILITY.
   462 
   463 * Made source layout more coherent with logical distribution
   464 structure:
   465 
   466     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   467     src/HOL/Library/Code_Message.thy ~> src/HOL/
   468     src/HOL/Library/GCD.thy ~> src/HOL/
   469     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   470     src/HOL/Library/Parity.thy ~> src/HOL/
   471     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   472     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   473     src/HOL/Real/Lubs.thy ~> src/HOL/
   474     src/HOL/Real/PReal.thy ~> src/HOL/
   475     src/HOL/Real/Rational.thy ~> src/HOL/
   476     src/HOL/Real/RComplete.thy ~> src/HOL/
   477     src/HOL/Real/RealDef.thy ~> src/HOL/
   478     src/HOL/Real/RealPow.thy ~> src/HOL/
   479     src/HOL/Real/Real.thy ~> src/HOL/
   480     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   481     src/HOL/Complex/Complex.thy ~> src/HOL/
   482     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   483     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   484     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   485     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   486     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   487     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   488     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   489     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   490     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   491     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   492     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   493     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   494     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   495     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   496     src/HOL/Real/Float ~> src/HOL/Library/
   497     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   498     src/HOL/Real/RealVector.thy ~> src/HOL/
   499 
   500     src/HOL/arith_data.ML ~> src/HOL/Tools
   501     src/HOL/hologic.ML ~> src/HOL/Tools
   502     src/HOL/simpdata.ML ~> src/HOL/Tools
   503     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   504     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   505     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   506     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   507     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   508     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   509     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   510 
   511     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   512     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   513     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   514     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   515     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   516     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   517 
   518 * If methods "eval" and "evaluation" encounter a structured proof
   519 state with !!/==>, only the conclusion is evaluated to True (if
   520 possible), avoiding strange error messages.
   521 
   522 * Method "sizechange" automates termination proofs using (a
   523 modification of) the size-change principle.  Requires SAT solver.  See
   524 src/HOL/ex/Termination.thy for examples.
   525 
   526 * Simplifier: simproc for let expressions now unfolds if bound
   527 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   528 
   529 * Method "arith": Linear arithmetic now ignores all inequalities when
   530 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   531 
   532 * New attribute "arith" for facts that should always be used
   533 automatically by arithmetic. It is intended to be used locally in
   534 proofs, e.g.
   535 
   536   assumes [arith]: "x > 0"
   537 
   538 Global usage is discouraged because of possible performance impact.
   539 
   540 * New classes "top" and "bot" with corresponding operations "top" and
   541 "bot" in theory Orderings; instantiation of class "complete_lattice"
   542 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   543 
   544 * Changed definition lemma "less_fun_def" in order to provide an
   545 instance for preorders on functions; use lemma "less_le" instead.
   546 INCOMPATIBILITY.
   547 
   548 * Theory Orderings: class "wellorder" moved here, with explicit
   549 induction rule "less_induct" as assumption.  For instantiation of
   550 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   551 INCOMPATIBILITY.
   552 
   553 * Theory Orderings: added class "preorder" as superclass of "order".
   554 INCOMPATIBILITY: Instantiation proofs for order, linorder
   555 etc. slightly changed.  Some theorems named order_class.* now named
   556 preorder_class.*.
   557 
   558 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   559 "diag" to "Id_on".
   560 
   561 * Theory Finite_Set: added a new fold combinator of type
   562 
   563   ('a => 'b => 'b) => 'b => 'a set => 'b
   564 
   565 Occasionally this is more convenient than the old fold combinator
   566 which is now defined in terms of the new one and renamed to
   567 fold_image.
   568 
   569 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   570 and "ring_simps" have been replaced by "algebra_simps" (which can be
   571 extended with further lemmas!).  At the moment both still exist but
   572 the former will disappear at some point.
   573 
   574 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   575 class recpower.  Type-specific simp rules for various recpower types
   576 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   577 
   578 rat_power_0    -> power_0
   579 rat_power_Suc  -> power_Suc
   580 realpow_0      -> power_0
   581 realpow_Suc    -> power_Suc
   582 complexpow_0   -> power_0
   583 complexpow_Suc -> power_Suc
   584 power_poly_0   -> power_0
   585 power_poly_Suc -> power_Suc
   586 
   587 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   588 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   589 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   590 of lemmas from Divides has been generalized from nat to class
   591 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   592 renames resulting from duplicate elimination:
   593 
   594     dvd_def_mod ~>          dvd_eq_mod_eq_0
   595     zero_dvd_iff ~>         dvd_0_left_iff
   596     dvd_0 ~>                dvd_0_right
   597     DIVISION_BY_ZERO_DIV ~> div_by_0
   598     DIVISION_BY_ZERO_MOD ~> mod_by_0
   599     mult_div ~>             div_mult_self2_is_id
   600     mult_mod ~>             mod_mult_self2_is_0
   601 
   602 * Theory IntDiv: removed many lemmas that are instances of class-based
   603 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   604 rename old lemmas as follows:
   605 
   606 dvd_diff               -> nat_dvd_diff
   607 dvd_zminus_iff         -> dvd_minus_iff
   608 mod_add1_eq            -> mod_add_eq
   609 mod_mult1_eq           -> mod_mult_right_eq
   610 mod_mult1_eq'          -> mod_mult_left_eq
   611 mod_mult_distrib_mod   -> mod_mult_eq
   612 nat_mod_add_left_eq    -> mod_add_left_eq
   613 nat_mod_add_right_eq   -> mod_add_right_eq
   614 nat_mod_div_trivial    -> mod_div_trivial
   615 nat_mod_mod_trivial    -> mod_mod_trivial
   616 zdiv_zadd_self1        -> div_add_self1
   617 zdiv_zadd_self2        -> div_add_self2
   618 zdiv_zmult_self1       -> div_mult_self2_is_id
   619 zdiv_zmult_self2       -> div_mult_self1_is_id
   620 zdvd_triv_left         -> dvd_triv_left
   621 zdvd_triv_right        -> dvd_triv_right
   622 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   623 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   624 zmod_zadd_left_eq      -> mod_add_left_eq
   625 zmod_zadd_right_eq     -> mod_add_right_eq
   626 zmod_zadd_self1        -> mod_add_self1
   627 zmod_zadd_self2        -> mod_add_self2
   628 zmod_zadd1_eq          -> mod_add_eq
   629 zmod_zdiff1_eq         -> mod_diff_eq
   630 zmod_zdvd_zmod         -> mod_mod_cancel
   631 zmod_zmod_cancel       -> mod_mod_cancel
   632 zmod_zmult_self1       -> mod_mult_self2_is_0
   633 zmod_zmult_self2       -> mod_mult_self1_is_0
   634 zmod_1                 -> mod_by_1
   635 zdiv_1                 -> div_by_1
   636 zdvd_abs1              -> abs_dvd_iff
   637 zdvd_abs2              -> dvd_abs_iff
   638 zdvd_refl              -> dvd_refl
   639 zdvd_trans             -> dvd_trans
   640 zdvd_zadd              -> dvd_add
   641 zdvd_zdiff             -> dvd_diff
   642 zdvd_zminus_iff        -> dvd_minus_iff
   643 zdvd_zminus2_iff       -> minus_dvd_iff
   644 zdvd_zmultD            -> dvd_mult_right
   645 zdvd_zmultD2           -> dvd_mult_left
   646 zdvd_zmult_mono        -> mult_dvd_mono
   647 zdvd_0_right           -> dvd_0_right
   648 zdvd_0_left            -> dvd_0_left_iff
   649 zdvd_1_left            -> one_dvd
   650 zminus_dvd_iff         -> minus_dvd_iff
   651 
   652 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   653 
   654 * The real numbers offer decimal input syntax: 12.34 is translated
   655 into 1234/10^2. This translation is not reversed upon output.
   656 
   657 * Theory Library/Polynomial defines an abstract type 'a poly of
   658 univariate polynomials with coefficients of type 'a.  In addition to
   659 the standard ring operations, it also supports div and mod.  Code
   660 generation is also supported, using list-style constructors.
   661 
   662 * Theory Library/Inner_Product defines a class of real_inner for real
   663 inner product spaces, with an overloaded operation inner :: 'a => 'a
   664 => real.  Class real_inner is a subclass of real_normed_vector from
   665 theory RealVector.
   666 
   667 * Theory Library/Product_Vector provides instances for the product
   668 type 'a * 'b of several classes from RealVector and Inner_Product.
   669 Definitions of addition, subtraction, scalar multiplication, norms,
   670 and inner products are included.
   671 
   672 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   673 addition to the field operations, numerals and case syntax are also
   674 supported.
   675 
   676 * Theory Library/Diagonalize provides constructive version of Cantor's
   677 first diagonalization argument.
   678 
   679 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   680 zlcm (for int); carried together from various gcd/lcm developements in
   681 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   682 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   683 may recover tupled syntax as follows:
   684 
   685     hide (open) const gcd
   686     abbreviation gcd where
   687       "gcd == (%(a, b). GCD.gcd a b)"
   688     notation (output)
   689       GCD.gcd ("gcd '(_, _')")
   690 
   691 The same works for lcm, zgcd, zlcm.
   692 
   693 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   694 instantiations for algebraic structures.  Removed some duplicate
   695 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   696 
   697 * ML antiquotation @{code} takes a constant as argument and generates
   698 corresponding code in background and inserts name of the corresponding
   699 resulting ML value/function/datatype constructor binding in place.
   700 All occurrences of @{code} with a single ML block are generated
   701 simultaneously.  Provides a generic and safe interface for
   702 instrumentalizing code generation.  See
   703 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   704 In future you ought to refrain from ad-hoc compiling generated SML
   705 code on the ML toplevel.  Note that (for technical reasons) @{code}
   706 cannot refer to constants for which user-defined serializations are
   707 set.  Refer to the corresponding ML counterpart directly in that
   708 cases.
   709 
   710 * Command 'rep_datatype': instead of theorem names the command now
   711 takes a list of terms denoting the constructors of the type to be
   712 represented as datatype.  The characteristic theorems have to be
   713 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   714 have disappeared in favour of existing ones:
   715 
   716     unit_induct                 ~> unit.induct
   717     prod_induct                 ~> prod.induct
   718     sum_induct                  ~> sum.induct
   719     Suc_Suc_eq                  ~> nat.inject
   720     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   721 
   722 
   723 *** HOL-Algebra ***
   724 
   725 * New locales for orders and lattices where the equivalence relation
   726 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   727 locales use a record structure with field eq for the equivalence.
   728 
   729 * New theory of factorial domains.
   730 
   731 * Units_l_inv and Units_r_inv are now simp rules by default.
   732 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   733 and/or r_inv will now also require deletion of these lemmas.
   734 
   735 * Renamed the following theorems, INCOMPATIBILITY:
   736 
   737 UpperD ~> Upper_memD
   738 LowerD ~> Lower_memD
   739 least_carrier ~> least_closed
   740 greatest_carrier ~> greatest_closed
   741 greatest_Lower_above ~> greatest_Lower_below
   742 one_zero ~> carrier_one_zero
   743 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   744 
   745 
   746 *** HOL-Nominal ***
   747 
   748 * Nominal datatypes can now contain type-variables.
   749 
   750 * Commands 'nominal_inductive' and 'equivariance' work with local
   751 theory targets.
   752 
   753 * Nominal primrec can now works with local theory targets and its
   754 specification syntax now conforms to the general format as seen in
   755 'inductive' etc.
   756 
   757 * Method "perm_simp" honours the standard simplifier attributes
   758 (no_asm), (no_asm_use) etc.
   759 
   760 * The new predicate #* is defined like freshness, except that on the
   761 left hand side can be a set or list of atoms.
   762 
   763 * Experimental command 'nominal_inductive2' derives strong induction
   764 principles for inductive definitions.  In contrast to
   765 'nominal_inductive', which can only deal with a fixed number of
   766 binders, it can deal with arbitrary expressions standing for sets of
   767 atoms to be avoided.  The only inductive definition we have at the
   768 moment that needs this generalisation is the typing rule for Lets in
   769 the algorithm W:
   770 
   771  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   772  -----------------------------------------------------------------
   773          Gamma |- Let x be t1 in t2 : T2
   774 
   775 In this rule one wants to avoid all the binders that are introduced by
   776 "close Gamma T1".  We are looking for other examples where this
   777 feature might be useful.  Please let us know.
   778 
   779 
   780 *** HOLCF ***
   781 
   782 * Reimplemented the simplification procedure for proving continuity
   783 subgoals.  The new simproc is extensible; users can declare additional
   784 continuity introduction rules with the attribute [cont2cont].
   785 
   786 * The continuity simproc now uses a different introduction rule for
   787 solving continuity subgoals on terms with lambda abstractions.  In
   788 some rare cases the new simproc may fail to solve subgoals that the
   789 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   790 Potential INCOMPATIBILITY.
   791 
   792 * Command 'fixrec': specification syntax now conforms to the general
   793 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   794 examples.  INCOMPATIBILITY.
   795 
   796 
   797 *** ZF ***
   798 
   799 * Proof of Zorn's Lemma for partial orders.
   800 
   801 
   802 *** ML ***
   803 
   804 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   805 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   806 depends on multithreading, so timouts will not work before Poly/ML
   807 5.2.1!
   808 
   809 * High-level support for concurrent ML programming, see
   810 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   811 particularly convenient to organize independent functional
   812 computations.  The concept of "synchronized variables" provides a
   813 higher-order interface for components with shared state, avoiding the
   814 delicate details of mutexes and condition variables.  (Requires
   815 Poly/ML 5.2.1 or later.)
   816 
   817 * ML bindings produced via Isar commands are stored within the Isar
   818 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   819 become thread-safe and work with undo as expected (concerning
   820 top-level bindings, not side-effects on global references).
   821 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   822 compiler at runtime; really global bindings need to be given outside a
   823 theory.  (Requires Poly/ML 5.2 or later.)
   824 
   825 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   826 context.  Top-level ML bindings are stored within the proof context in
   827 a purely sequential fashion, disregarding the nested proof structure.
   828 ML bindings introduced by 'ML_prf' are discarded at the end of the
   829 proof.  (Requires Poly/ML 5.2 or later.)
   830 
   831 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   832 and Method.setup, as well as Isar commands 'attribute_setup' and
   833 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   834 existing code accordingly, or use plain 'setup' together with old
   835 Method.add_method.
   836 
   837 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   838 to 'a -> thm, while results are always tagged with an authentic oracle
   839 name.  The Isar command 'oracle' is now polymorphic, no argument type
   840 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   841 accordingly.  Note that extra performance may be gained by producing
   842 the cterm carefully, avoiding slow Thm.cterm_of.
   843 
   844 * Simplified interface for defining document antiquotations via
   845 ThyOutput.antiquotation, ThyOutput.output, and optionally
   846 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   847 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   848 examples.
   849 
   850 * More systematic treatment of long names, abstract name bindings, and
   851 name space operations.  Basic operations on qualified names have been
   852 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   853 Long_Name.append.  Old type bstring has been mostly replaced by
   854 abstract type binding (see structure Binding), which supports precise
   855 qualification by packages and local theory targets, as well as proper
   856 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   857 bstring values into Binding.name, or better pass through abstract
   858 bindings everywhere.  See further src/Pure/General/long_name.ML,
   859 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   860 
   861 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   862 LocalTheory.note etc.) now refer to the *full* internal name, not the
   863 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   864 
   865 * Disposed old type and term read functions (Sign.read_def_typ,
   866 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   867 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   868 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   869 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   870 resort for legacy applications.
   871 
   872 * Disposed old declarations, tactics, tactic combinators that refer to
   873 the simpset or claset of an implicit theory (such as Addsimps,
   874 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   875 embedded ML text, or local_simpset_of with a proper context passed as
   876 explicit runtime argument.
   877 
   878 * Rules and tactics that read instantiations (read_instantiate,
   879 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   880 context, which is required for parsing and type-checking.  Moreover,
   881 the variables are specified as plain indexnames, not string encodings
   882 thereof.  INCOMPATIBILITY.
   883 
   884 * Generic Toplevel.add_hook interface allows to analyze the result of
   885 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   886 for theorem dependency output of transactions resulting in a new
   887 theory state.
   888 
   889 * ML antiquotations: block-structured compilation context indicated by
   890 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   891 
   892   @{binding name}                         - basic name binding
   893   @{let ?pat = term}                      - term abbreviation (HO matching)
   894   @{note name = fact}                     - fact abbreviation
   895   @{thm fact}                             - singleton fact (with attributes)
   896   @{thms fact}                            - general fact (with attributes)
   897   @{lemma prop by method}                 - singleton goal
   898   @{lemma prop by meth1 meth2}            - singleton goal
   899   @{lemma prop1 ... propN by method}      - general goal
   900   @{lemma prop1 ... propN by meth1 meth2} - general goal
   901   @{lemma (open) ...}                     - open derivation
   902 
   903 
   904 *** System ***
   905 
   906 * The Isabelle "emacs" tool provides a specific interface to invoke
   907 Proof General / Emacs, with more explicit failure if that is not
   908 installed (the old isabelle-interface script silently falls back on
   909 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   910 installation location of the Proof General distribution.
   911 
   912 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   913 the Isabelle process into a JVM/Scala application.  See
   914 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   915 process wrapper has been discontinued.)
   916 
   917 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   918 
   919 * Various status messages (with exact source position information) are
   920 emitted, if proper markup print mode is enabled.  This allows
   921 user-interface components to provide detailed feedback on internal
   922 prover operations.
   923 
   924 
   925 
   926 New in Isabelle2008 (June 2008)
   927 -------------------------------
   928 
   929 *** General ***
   930 
   931 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   932 and updated, with formally checked references as hyperlinks.
   933 
   934 * Theory loader: use_thy (and similar operations) no longer set the
   935 implicit ML context, which was occasionally hard to predict and in
   936 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   937 provides a proper context already.
   938 
   939 * Theory loader: old-style ML proof scripts being *attached* to a thy
   940 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   941 'use' within a theory file will do the job.
   942 
   943 * Name space merge now observes canonical order, i.e. the second space
   944 is inserted into the first one, while existing entries in the first
   945 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   946 swap theory imports.
   947 
   948 * Syntax: symbol \<chi> is now considered a letter.  Potential
   949 INCOMPATIBILITY in identifier syntax etc.
   950 
   951 * Outer syntax: string tokens no longer admit escaped white space,
   952 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   953 white space without escapes.
   954 
   955 * Outer syntax: string tokens may contain arbitrary character codes
   956 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   957 "foo_bar".
   958 
   959 
   960 *** Pure ***
   961 
   962 * Context-dependent token translations.  Default setup reverts locally
   963 fixed variables, and adds hilite markup for undeclared frees.
   964 
   965 * Unused theorems can be found using the new command 'unused_thms'.
   966 There are three ways of invoking it:
   967 
   968 (1) unused_thms
   969      Only finds unused theorems in the current theory.
   970 
   971 (2) unused_thms thy_1 ... thy_n -
   972      Finds unused theorems in the current theory and all of its ancestors,
   973      excluding the theories thy_1 ... thy_n and all of their ancestors.
   974 
   975 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   976      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   977      their ancestors, excluding the theories thy_1 ... thy_n and all of
   978      their ancestors.
   979 
   980 In order to increase the readability of the list produced by
   981 unused_thms, theorems that have been created by a particular instance
   982 of a theory command such as 'inductive' or 'function' are considered
   983 to belong to the same "group", meaning that if at least one theorem in
   984 this group is used, the other theorems in the same group are no longer
   985 reported as unused.  Moreover, if all theorems in the group are
   986 unused, only one theorem in the group is displayed.
   987 
   988 Note that proof objects have to be switched on in order for
   989 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   990 usually the case when using Proof General with the default settings).
   991 
   992 * Authentic naming of facts disallows ad-hoc overwriting of previous
   993 theorems within the same name space.  INCOMPATIBILITY, need to remove
   994 duplicate fact bindings, or even accidental fact duplications.  Note
   995 that tools may maintain dynamically scoped facts systematically, using
   996 PureThy.add_thms_dynamic.
   997 
   998 * Command 'hide' now allows to hide from "fact" name space as well.
   999 
  1000 * Eliminated destructive theorem database, simpset, claset, and
  1001 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
  1002 update of theories within ML code.
  1003 
  1004 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
  1005 INCOMPATIBILITY, object-logics depending on former Pure require
  1006 additional setup PureThy.old_appl_syntax_setup; object-logics
  1007 depending on former CPure need to refer to Pure.
  1008 
  1009 * Commands 'use' and 'ML' are now purely functional, operating on
  1010 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
  1011 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
  1012 INCOMPATIBILITY.
  1013 
  1014 * Command 'setup': discontinued implicit version with ML reference.
  1015 
  1016 * Instantiation target allows for simultaneous specification of class
  1017 instance operations together with an instantiation proof.
  1018 Type-checking phase allows to refer to class operations uniformly.
  1019 See src/HOL/Complex/Complex.thy for an Isar example and
  1020 src/HOL/Library/Eval.thy for an ML example.
  1021 
  1022 * Indexing of literal facts: be more serious about including only
  1023 facts from the visible specification/proof context, but not the
  1024 background context (locale etc.).  Affects `prop` notation and method
  1025 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
  1026 situations.
  1027 
  1028 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
  1029 "(open)" option, which used to expose internal bound variables to the
  1030 proof text.
  1031 
  1032 * Isar statements: removed obsolete case "rule_context".
  1033 INCOMPATIBILITY, better use explicit fixes/assumes.
  1034 
  1035 * Locale proofs: default proof step now includes 'unfold_locales';
  1036 hence 'proof' without argument may be used to unfold locale
  1037 predicates.
  1038 
  1039 
  1040 *** Document preparation ***
  1041 
  1042 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
  1043 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
  1044 obsolete thumbpdf setup (contemporary PDF viewers do this on the
  1045 spot); renamed link color from "darkblue" to "linkcolor" (default
  1046 value unchanged, can be redefined via \definecolor); no longer sets
  1047 "a4paper" option (unnecessary or even intrusive).
  1048 
  1049 * Antiquotation @{lemma A method} proves proposition A by the given
  1050 method (either a method name or a method name plus (optional) method
  1051 arguments in parentheses) and prints A just like @{prop A}.
  1052 
  1053 
  1054 *** HOL ***
  1055 
  1056 * New primrec package.  Specification syntax conforms in style to
  1057 definition/function/....  No separate induction rule is provided.  The
  1058 "primrec" command distinguishes old-style and new-style specifications
  1059 by syntax.  The former primrec package is now named OldPrimrecPackage.
  1060 When adjusting theories, beware: constants stemming from new-style
  1061 primrec specifications have authentic syntax.
  1062 
  1063 * Metis prover is now an order of magnitude faster, and also works
  1064 with multithreading.
  1065 
  1066 * Metis: the maximum number of clauses that can be produced from a
  1067 theorem is now given by the attribute max_clauses.  Theorems that
  1068 exceed this number are ignored, with a warning printed.
  1069 
  1070 * Sledgehammer no longer produces structured proofs by default. To
  1071 enable, declare [[sledgehammer_full = true]].  Attributes
  1072 reconstruction_modulus, reconstruction_sorts renamed
  1073 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
  1074 
  1075 * Method "induct_scheme" derives user-specified induction rules
  1076 from well-founded induction and completeness of patterns. This factors
  1077 out some operations that are done internally by the function package
  1078 and makes them available separately.  See
  1079 src/HOL/ex/Induction_Scheme.thy for examples.
  1080 
  1081 * More flexible generation of measure functions for termination
  1082 proofs: Measure functions can be declared by proving a rule of the
  1083 form "is_measure f" and giving it the [measure_function] attribute.
  1084 The "is_measure" predicate is logically meaningless (always true), and
  1085 just guides the heuristic.  To find suitable measure functions, the
  1086 termination prover sets up the goal "is_measure ?f" of the appropriate
  1087 type and generates all solutions by prolog-style backwards proof using
  1088 the declared rules.
  1089 
  1090 This setup also deals with rules like 
  1091 
  1092   "is_measure f ==> is_measure (list_size f)"
  1093 
  1094 which accommodates nested datatypes that recurse through lists.
  1095 Similar rules are predeclared for products and option types.
  1096 
  1097 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
  1098 
  1099   INCOMPATIBILITIES:
  1100 
  1101   - Definitions of overloaded constants on sets have to be replaced by
  1102     definitions on => and bool.
  1103 
  1104   - Some definitions of overloaded operators on sets can now be proved
  1105     using the definitions of the operators on => and bool.  Therefore,
  1106     the following theorems have been renamed:
  1107 
  1108       subset_def   -> subset_eq
  1109       psubset_def  -> psubset_eq
  1110       set_diff_def -> set_diff_eq
  1111       Compl_def    -> Compl_eq
  1112       Sup_set_def  -> Sup_set_eq
  1113       Inf_set_def  -> Inf_set_eq
  1114       sup_set_def  -> sup_set_eq
  1115       inf_set_def  -> inf_set_eq
  1116 
  1117   - Due to the incompleteness of the HO unification algorithm, some
  1118     rules such as subst may require manual instantiation, if some of
  1119     the unknowns in the rule is a set.
  1120 
  1121   - Higher order unification and forward proofs:
  1122     The proof pattern
  1123 
  1124       have "P (S::'a set)" <...>
  1125       then have "EX S. P S" ..
  1126 
  1127     no longer works (due to the incompleteness of the HO unification
  1128     algorithm) and must be replaced by the pattern
  1129 
  1130       have "EX S. P S"
  1131       proof
  1132         show "P S" <...>
  1133       qed
  1134 
  1135   - Calculational reasoning with subst (or similar rules):
  1136     The proof pattern
  1137 
  1138       have "P (S::'a set)" <...>
  1139       also have "S = T" <...>
  1140       finally have "P T" .
  1141 
  1142     no longer works (for similar reasons as the previous example) and
  1143     must be replaced by something like
  1144 
  1145       have "P (S::'a set)" <...>
  1146       moreover have "S = T" <...>
  1147       ultimately have "P T" by simp
  1148 
  1149   - Tactics or packages written in ML code:
  1150     Code performing pattern matching on types via
  1151 
  1152       Type ("set", [T]) => ...
  1153 
  1154     must be rewritten. Moreover, functions like strip_type or
  1155     binder_types no longer return the right value when applied to a
  1156     type of the form
  1157 
  1158       T1 => ... => Tn => U => bool
  1159 
  1160     rather than
  1161 
  1162       T1 => ... => Tn => U set
  1163 
  1164 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1165 Wellfounded_Relations to theory Wellfounded.
  1166 
  1167 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1168 
  1169 * Class finite no longer treats UNIV as class parameter.  Use class
  1170 enum from theory Library/Enum instead to achieve a similar effect.
  1171 INCOMPATIBILITY.
  1172 
  1173 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1174 and "Cons".  INCOMPATIBILITY.
  1175 
  1176 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1177 Potential INCOMPATIBILITY.
  1178 
  1179 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1180 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1181 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1182 
  1183 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1184 the same name in theory Orderings:
  1185 
  1186   less_trans
  1187   less_linear
  1188   le_imp_less_or_eq
  1189   le_less_trans
  1190   less_le_trans
  1191   less_not_sym
  1192   less_asym
  1193 
  1194 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1195 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1196 and different variable names.
  1197 
  1198 * Library/Option_ord.thy: Canonical order on option type.
  1199 
  1200 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1201 finite maps.
  1202 
  1203 * Library/Countable.thy: Type class for countable types.
  1204 
  1205 * Theory Int: The representation of numerals has changed.  The infix
  1206 operator BIT and the bit datatype with constructors B0 and B1 have
  1207 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1208 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1209 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1210 accordingly.
  1211 
  1212 * Theory Nat: definition of <= and < on natural numbers no longer
  1213 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1214 le_def and less_def have disappeared.  Consider lemmas not_less
  1215 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1216 
  1217 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1218 (whose purpose mainly is for various fold_set functionals) have been
  1219 abandoned in favor of the existing algebraic classes
  1220 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1221 lower_semilattice (resp. upper_semilattice) and linorder.
  1222 INCOMPATIBILITY.
  1223 
  1224 * Theory Transitive_Closure: induct and cases rules now declare proper
  1225 case_names ("base" and "step").  INCOMPATIBILITY.
  1226 
  1227 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1228 lattices.  The form set-specific version is available as
  1229 Inductive.lfp_ordinal_induct_set.
  1230 
  1231 * Renamed theorems "power.simps" to "power_int.simps".
  1232 INCOMPATIBILITY.
  1233 
  1234 * Class semiring_div provides basic abstract properties of semirings
  1235 with division and modulo operations.  Subsumes former class dvd_mod.
  1236 
  1237 * Merged theories IntDef, Numeral and IntArith into unified theory
  1238 Int.  INCOMPATIBILITY.
  1239 
  1240 * Theory Library/Code_Index: type "index" now represents natural
  1241 numbers rather than integers.  INCOMPATIBILITY.
  1242 
  1243 * New class "uminus" with operation "uminus" (split of from class
  1244 "minus" which now only has operation "minus", binary).
  1245 INCOMPATIBILITY.
  1246 
  1247 * Constants "card", "internal_split", "option_map" now with authentic
  1248 syntax.  INCOMPATIBILITY.
  1249 
  1250 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1251 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1252 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1253 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1254 Sup_set_def, le_def, less_def, option_map_def now with object
  1255 equality.  INCOMPATIBILITY.
  1256 
  1257 * Records. Removed K_record, and replaced it by pure lambda term
  1258 %x. c. The simplifier setup is now more robust against eta expansion.
  1259 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1260 
  1261 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1262 
  1263 * Library/ListVector: new theory of arithmetic vector operations.
  1264 
  1265 * Library/Order_Relation: new theory of various orderings as sets of
  1266 pairs.  Defines preorders, partial orders, linear orders and
  1267 well-orders on sets and on types.
  1268 
  1269 
  1270 *** ZF ***
  1271 
  1272 * Renamed some theories to allow to loading both ZF and HOL in the
  1273 same session:
  1274 
  1275   Datatype  -> Datatype_ZF
  1276   Inductive -> Inductive_ZF
  1277   Int       -> Int_ZF
  1278   IntDiv    -> IntDiv_ZF
  1279   Nat       -> Nat_ZF
  1280   List      -> List_ZF
  1281   Main      -> Main_ZF
  1282 
  1283 INCOMPATIBILITY: ZF theories that import individual theories below
  1284 Main might need to be adapted.  Regular theory Main is still
  1285 available, as trivial extension of Main_ZF.
  1286 
  1287 
  1288 *** ML ***
  1289 
  1290 * ML within Isar: antiquotation @{const name} or @{const
  1291 name(typargs)} produces statically-checked Const term.
  1292 
  1293 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1294 (of the same name).  Removed obsolete print command.
  1295 
  1296 * Removed obsolete "use_legacy_bindings" function.
  1297 
  1298 * The ``print mode'' is now a thread-local value derived from a global
  1299 template (the former print_mode reference), thus access becomes
  1300 non-critical.  The global print_mode reference is for session
  1301 management only; user-code should use print_mode_value,
  1302 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1303 
  1304 * Functions system/system_out provide a robust way to invoke external
  1305 shell commands, with propagation of interrupts (requires Poly/ML
  1306 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1307 
  1308 
  1309 *** System ***
  1310 
  1311 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1312 in accordance with Proof General 3.7, which prefers GNU emacs.
  1313 
  1314 * isatool tty runs Isabelle process with plain tty interaction;
  1315 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1316 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1317 
  1318 * isatool browser now works with Cygwin as well, using general
  1319 "javapath" function defined in Isabelle process environment.
  1320 
  1321 * YXML notation provides a simple and efficient alternative to
  1322 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1323 isatool yxml as described in the Isabelle system manual.
  1324 
  1325 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1326 provides general wrapper for managing an Isabelle process in a robust
  1327 fashion, with ``cooked'' output from stdin/stderr.
  1328 
  1329 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1330 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1331 
  1332 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1333 way of changing the user's settings is via
  1334 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1335 script.
  1336 
  1337 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1338 cores of the underlying machine, which is a good starting point for
  1339 optimal performance tuning.  The corresponding usedir option -M allows
  1340 "max" as an alias for "0".  WARNING: does not work on certain versions
  1341 of Mac OS (with Poly/ML 5.1).
  1342 
  1343 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1344 adverse effect of Isabelle flooding interactive front-ends (notably
  1345 ProofGeneral / XEmacs).
  1346 
  1347 
  1348 
  1349 New in Isabelle2007 (November 2007)
  1350 -----------------------------------
  1351 
  1352 *** General ***
  1353 
  1354 * More uniform information about legacy features, notably a
  1355 warning/error of "Legacy feature: ...", depending on the state of the
  1356 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1357 legacy features will disappear eventually.
  1358 
  1359 * Theory syntax: the header format ``theory A = B + C:'' has been
  1360 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1361 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1362 
  1363 * Theory syntax: the old non-Isar theory file format has been
  1364 discontinued altogether.  Note that ML proof scripts may still be used
  1365 with Isar theories; migration is usually quite simple with the ML
  1366 function use_legacy_bindings.  INCOMPATIBILITY.
  1367 
  1368 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1369 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1370 quotes.
  1371 
  1372 * Theory loader: be more serious about observing the static theory
  1373 header specifications (including optional directories), but not the
  1374 accidental file locations of previously successful loads.  The strict
  1375 update policy of former update_thy is now already performed by
  1376 use_thy, so the former has been removed; use_thys updates several
  1377 theories simultaneously, just as 'imports' within a theory header
  1378 specification, but without merging the results.  Potential
  1379 INCOMPATIBILITY: may need to refine theory headers and commands
  1380 ROOT.ML which depend on load order.
  1381 
  1382 * Theory loader: optional support for content-based file
  1383 identification, instead of the traditional scheme of full physical
  1384 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1385 (cf. the system manual).  The new scheme allows to work with
  1386 non-finished theories in persistent session images, such that source
  1387 files may be moved later on without requiring reloads.
  1388 
  1389 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1390 file (with the same base name as the theory) are considered a legacy
  1391 feature, which will disappear eventually. Even now, the theory loader
  1392 no longer maintains dependencies on such files.
  1393 
  1394 * Syntax: the scope for resolving ambiguities via type-inference is
  1395 now limited to individual terms, instead of whole simultaneous
  1396 specifications as before. This greatly reduces the complexity of the
  1397 syntax module and improves flexibility by separating parsing and
  1398 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1399 'fixes' etc.) are required in rare situations.
  1400 
  1401 * Syntax: constants introduced by new-style packages ('definition',
  1402 'abbreviation' etc.) are passed through the syntax module in
  1403 ``authentic mode''. This means that associated mixfix annotations
  1404 really stick to such constants, independently of potential name space
  1405 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1406 trees are represented slightly differently, may need to adapt syntax
  1407 translations accordingly. Use CONST marker in 'translations' and
  1408 @{const_syntax} antiquotation in 'parse_translation' etc.
  1409 
  1410 * Legacy goal package: reduced interface to the bare minimum required
  1411 to keep existing proof scripts running.  Most other user-level
  1412 functions are now part of the OldGoals structure, which is *not* open
  1413 by default (consider isatool expandshort before open OldGoals).
  1414 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1415 these tend to cause confusion about the actual goal (!) context being
  1416 used here, which is not necessarily the same as the_context().
  1417 
  1418 * Command 'find_theorems': supports "*" wild-card in "name:"
  1419 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1420 support a specific search form (see ProofGeneral/CHANGES).
  1421 
  1422 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1423 by default, which means that "prems" (and also "fixed variables") are
  1424 suppressed from proof state output.  Note that the ProofGeneral
  1425 settings mechanism allows to change and save options persistently, but
  1426 older versions of Isabelle will fail to start up if a negative prems
  1427 limit is imposed.
  1428 
  1429 * Local theory targets may be specified by non-nested blocks of
  1430 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1431 contain definitions, theorems etc., including any derived mechanism
  1432 that has been implemented on top of these primitives.  This concept
  1433 generalizes the existing ``theorem (in ...)'' towards more versatility
  1434 and scalability.
  1435 
  1436 * Proof General interface: proper undo of final 'end' command;
  1437 discontinued Isabelle/classic mode (ML proof scripts).
  1438 
  1439 
  1440 *** Document preparation ***
  1441 
  1442 * Added antiquotation @{theory name} which prints the given name,
  1443 after checking that it refers to a valid ancestor theory in the
  1444 current context.
  1445 
  1446 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1447 check the given source text as ML type/structure, printing verbatim.
  1448 
  1449 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1450 "c args == rhs" given in the current context.  (Any number of
  1451 arguments may be given on the LHS.)
  1452 
  1453 
  1454 *** Pure ***
  1455 
  1456 * The 'class' package offers a combination of axclass and locale to
  1457 achieve Haskell-like type classes in Isabelle.  Definitions and
  1458 theorems within a class context produce both relative results (with
  1459 implicit parameters according to the locale context), and polymorphic
  1460 constants with qualified polymorphism (according to the class
  1461 context).  Within the body context of a 'class' target, a separate
  1462 syntax layer ("user space type system") takes care of converting
  1463 between global polymorphic consts and internal locale representation.
  1464 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1465 "isatool doc classes" provides a tutorial.
  1466 
  1467 * Generic code generator framework allows to generate executable
  1468 code for ML and Haskell (including Isabelle classes).  A short usage
  1469 sketch:
  1470 
  1471     internal compilation:
  1472         export_code <list of constants (term syntax)> in SML
  1473     writing SML code to a file:
  1474         export_code <list of constants (term syntax)> in SML <filename>
  1475     writing OCaml code to a file:
  1476         export_code <list of constants (term syntax)> in OCaml <filename>
  1477     writing Haskell code to a bunch of files:
  1478         export_code <list of constants (term syntax)> in Haskell <filename>
  1479 
  1480     evaluating closed propositions to True/False using code generation:
  1481         method ``eval''
  1482 
  1483 Reasonable default setup of framework in HOL.
  1484 
  1485 Theorem attributs for selecting and transforming function equations theorems:
  1486 
  1487     [code fun]:        select a theorem as function equation for a specific constant
  1488     [code fun del]:    deselect a theorem as function equation for a specific constant
  1489     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1490     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1491 
  1492 User-defined serializations (target in {SML, OCaml, Haskell}):
  1493 
  1494     code_const <and-list of constants (term syntax)>
  1495       {(target) <and-list of const target syntax>}+
  1496 
  1497     code_type <and-list of type constructors>
  1498       {(target) <and-list of type target syntax>}+
  1499 
  1500     code_instance <and-list of instances>
  1501       {(target)}+
  1502         where instance ::= <type constructor> :: <class>
  1503 
  1504     code_class <and_list of classes>
  1505       {(target) <and-list of class target syntax>}+
  1506         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1507 
  1508 code_instance and code_class only are effective to target Haskell.
  1509 
  1510 For example usage see src/HOL/ex/Codegenerator.thy and
  1511 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1512 generation from Isabelle/HOL theories is available via "isatool doc
  1513 codegen".
  1514 
  1515 * Code generator: consts in 'consts_code' Isar commands are now
  1516 referred to by usual term syntax (including optional type
  1517 annotations).
  1518 
  1519 * Command 'no_translations' removes translation rules from theory
  1520 syntax.
  1521 
  1522 * Overloaded definitions are now actually checked for acyclic
  1523 dependencies.  The overloading scheme is slightly more general than
  1524 that of Haskell98, although Isabelle does not demand an exact
  1525 correspondence to type class and instance declarations.
  1526 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1527 exotic versions of overloading -- at the discretion of the user!
  1528 
  1529 Polymorphic constants are represented via type arguments, i.e. the
  1530 instantiation that matches an instance against the most general
  1531 declaration given in the signature.  For example, with the declaration
  1532 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1533 as c(nat).  Overloading is essentially simultaneous structural
  1534 recursion over such type arguments.  Incomplete specification patterns
  1535 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1536 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1537 Command 'print_theory' outputs the normalized system of recursive
  1538 equations, see section "definitions".
  1539 
  1540 * Configuration options are maintained within the theory or proof
  1541 context (with name and type bool/int/string), providing a very simple
  1542 interface to a poor-man's version of general context data.  Tools may
  1543 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1544 these values using Config.get etc.  Users may change options via an
  1545 associated attribute of the same name.  This form of context
  1546 declaration works particularly well with commands 'declare' or
  1547 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1548 very easy to avoid global references, which would not observe Isar
  1549 toplevel undo/redo and fail to work with multithreading.
  1550 
  1551 Various global ML references of Pure and HOL have been turned into
  1552 configuration options:
  1553 
  1554   Unify.search_bound		unify_search_bound
  1555   Unify.trace_bound		unify_trace_bound
  1556   Unify.trace_simp		unify_trace_simp
  1557   Unify.trace_types		unify_trace_types
  1558   Simplifier.simp_depth_limit	simp_depth_limit
  1559   Blast.depth_limit		blast_depth_limit
  1560   DatatypeProp.dtK		datatype_distinctness_limit
  1561   fast_arith_neq_limit  	fast_arith_neq_limit
  1562   fast_arith_split_limit	fast_arith_split_limit
  1563 
  1564 * Named collections of theorems may be easily installed as context
  1565 data using the functor NamedThmsFun (see also
  1566 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1567 attributes; there is also a toplevel print command.  This facility is
  1568 just a common case of general context data, which is the preferred way
  1569 for anything more complex than just a list of facts in canonical
  1570 order.
  1571 
  1572 * Isar: command 'declaration' augments a local theory by generic
  1573 declaration functions written in ML.  This enables arbitrary content
  1574 being added to the context, depending on a morphism that tells the
  1575 difference of the original declaration context wrt. the application
  1576 context encountered later on.
  1577 
  1578 * Isar: proper interfaces for simplification procedures.  Command
  1579 'simproc_setup' declares named simprocs (with match patterns, and body
  1580 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1581 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1582 
  1583 * Isar: an extra pair of brackets around attribute declarations
  1584 abbreviates a theorem reference involving an internal dummy fact,
  1585 which will be ignored later --- only the effect of the attribute on
  1586 the background context will persist.  This form of in-place
  1587 declarations is particularly useful with commands like 'declare' and
  1588 'using', for example ``have A using [[simproc a]] by simp''.
  1589 
  1590 * Isar: method "assumption" (and implicit closing of subproofs) now
  1591 takes simple non-atomic goal assumptions into account: after applying
  1592 an assumption as a rule the resulting subgoals are solved by atomic
  1593 assumption steps.  This is particularly useful to finish 'obtain'
  1594 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1595 without referring to the original premise "!!x. P x ==> thesis" in the
  1596 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1597 more permissive.
  1598 
  1599 * Isar: implicit use of prems from the Isar proof context is
  1600 considered a legacy feature.  Common applications like ``have A .''
  1601 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1602 referencing facts explicitly here improves readability and
  1603 maintainability of proof texts.
  1604 
  1605 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1606 the obtained context from the course of reasoning!  For example:
  1607 
  1608   assume "EX x y. A x & B y"   -- "any previous fact"
  1609   then guess x and y by clarify
  1610 
  1611 This technique is potentially adventurous, depending on the facts and
  1612 proof tools being involved here.
  1613 
  1614 * Isar: known facts from the proof context may be specified as literal
  1615 propositions, using ASCII back-quote syntax.  This works wherever
  1616 named facts used to be allowed so far, in proof commands, proof
  1617 methods, attributes etc.  Literal facts are retrieved from the context
  1618 according to unification of type and term parameters.  For example,
  1619 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1620 theorems in the current context, then these are valid literal facts:
  1621 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1622 
  1623 There is also a proof method "fact" which does the same composition
  1624 for explicit goal states, e.g. the following proof texts coincide with
  1625 certain special cases of literal facts:
  1626 
  1627   have "A" by fact                 ==  note `A`
  1628   have "A ==> B" by fact           ==  note `A ==> B`
  1629   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1630   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1631 
  1632 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1633 outer syntax.  Thus symbolic identifiers may be used without
  1634 additional white space in declarations like this: ``assume *: A''.
  1635 
  1636 * Isar: 'print_facts' prints all local facts of the current context,
  1637 both named and unnamed ones.
  1638 
  1639 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1640 
  1641   def x == "t" and y == "u"
  1642 
  1643 * Isar: added command 'unfolding', which is structurally similar to
  1644 'using', but affects both the goal state and facts by unfolding given
  1645 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1646 'unfolded' attribute may be replaced by first-class proof text.
  1647 
  1648 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1649 and command 'unfolding' now all support object-level equalities
  1650 (potentially conditional).  The underlying notion of rewrite rule is
  1651 analogous to the 'rule_format' attribute, but *not* that of the
  1652 Simplifier (which is usually more generous).
  1653 
  1654 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1655 premises of a theorem by n. Useful in conjunction with drule.
  1656 
  1657 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1658 method expression within a sandbox consisting of the first N
  1659 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1660 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1661 simplifies all new goals that emerge from applying rule foo to the
  1662 originally first one.
  1663 
  1664 * Isar: schematic goals are no longer restricted to higher-order
  1665 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1666 expected.
  1667 
  1668 * Isar: the conclusion of a long theorem statement is now either
  1669 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1670 (essentially a disjunction of cases with local parameters and
  1671 assumptions).  The latter allows to express general elimination rules
  1672 adequately; in this notation common elimination rules look like this:
  1673 
  1674   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1675     assumes "EX x. P x"
  1676     obtains x where "P x"
  1677 
  1678   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1679     assumes "A & B"
  1680     obtains A and B
  1681 
  1682   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1683     assumes "A | B"
  1684     obtains
  1685       A
  1686     | B
  1687 
  1688 The subsequent classical rules even refer to the formal "thesis"
  1689 explicitly:
  1690 
  1691   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1692     obtains "~ thesis"
  1693 
  1694   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1695     obtains "thesis ==> something"
  1696 
  1697 The actual proof of an 'obtains' statement is analogous to that of the
  1698 Isar proof element 'obtain', only that there may be several cases.
  1699 Optional case names may be specified in parentheses; these will be
  1700 available both in the present proof and as annotations in the
  1701 resulting rule, for later use with the 'cases' method (cf. attribute
  1702 case_names).
  1703 
  1704 * Isar: the assumptions of a long theorem statement are available as
  1705 "assms" fact in the proof context.  This is more appropriate than the
  1706 (historical) "prems", which refers to all assumptions of the current
  1707 context, including those from the target locale, proof body etc.
  1708 
  1709 * Isar: 'print_statement' prints theorems from the current theory or
  1710 proof context in long statement form, according to the syntax of a
  1711 top-level lemma.
  1712 
  1713 * Isar: 'obtain' takes an optional case name for the local context
  1714 introduction rule (default "that").
  1715 
  1716 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1717 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1718 to occur.
  1719 
  1720 * Pure: syntax "CONST name" produces a fully internalized constant
  1721 according to the current context.  This is particularly useful for
  1722 syntax translations that should refer to internal constant
  1723 representations independently of name spaces.
  1724 
  1725 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1726 instead of "FOO ". This allows multiple binder declarations to coexist
  1727 in the same context.  INCOMPATIBILITY.
  1728 
  1729 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1730 primitive that also works in a locale context (both for constants and
  1731 fixed variables). Type declaration and internal syntactic representation
  1732 of given constants retrieved from the context. Likewise, the
  1733 'no_notation' command allows to remove given syntax annotations from the
  1734 current context.
  1735 
  1736 * Isar/locales: new derived specification elements 'axiomatization',
  1737 'definition', 'abbreviation', which support type-inference, admit
  1738 object-level specifications (equality, equivalence).  See also the
  1739 isar-ref manual.  Examples:
  1740 
  1741   axiomatization
  1742     eq  (infix "===" 50) where
  1743     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1744 
  1745   definition "f x y = x + y + 1"
  1746   definition g where "g x = f x x"
  1747 
  1748   abbreviation
  1749     neq  (infix "=!=" 50) where
  1750     "x =!= y == ~ (x === y)"
  1751 
  1752 These specifications may be also used in a locale context.  Then the
  1753 constants being introduced depend on certain fixed parameters, and the
  1754 constant name is qualified by the locale base name.  An internal
  1755 abbreviation takes care for convenient input and output, making the
  1756 parameters implicit and using the original short name.  See also
  1757 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1758 entities from a monomorphic theory.
  1759 
  1760 Presently, abbreviations are only available 'in' a target locale, but
  1761 not inherited by general import expressions.  Also note that
  1762 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1763 'translations' in common applications.  The "no_abbrevs" print mode
  1764 prevents folding of abbreviations in term output.
  1765 
  1766 Concrete syntax is attached to specified constants in internal form,
  1767 independently of name spaces.  The parse tree representation is
  1768 slightly different -- use 'notation' instead of raw 'syntax', and
  1769 'translations' with explicit "CONST" markup to accommodate this.
  1770 
  1771 * Pure/Isar: unified syntax for new-style specification mechanisms
  1772 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1773 full type inference and dummy patterns ("_").  For example:
  1774 
  1775   definition "K x _ = x"
  1776 
  1777   inductive conj for A B
  1778   where "A ==> B ==> conj A B"
  1779 
  1780 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1781 the current context.  Print mode "no_abbrevs" prevents inversion of
  1782 abbreviations on output.
  1783 
  1784 * Isar/locales: improved parameter handling: use of locales "var" and
  1785 "struct" no longer necessary; - parameter renamings are no longer
  1786 required to be injective.  For example, this allows to define
  1787 endomorphisms as locale endom = homom mult mult h.
  1788 
  1789 * Isar/locales: changed the way locales with predicates are defined.
  1790 Instead of accumulating the specification, the imported expression is
  1791 now an interpretation.  INCOMPATIBILITY: different normal form of
  1792 locale expressions.  In particular, in interpretations of locales with
  1793 predicates, goals repesenting already interpreted fragments are not
  1794 removed automatically.  Use methods `intro_locales' and
  1795 `unfold_locales'; see below.
  1796 
  1797 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1798 provide backward reasoning on locales predicates.  The methods are
  1799 aware of interpretations and discharge corresponding goals.
  1800 `intro_locales' is less aggressive then `unfold_locales' and does not
  1801 unfold predicates to assumptions.
  1802 
  1803 * Isar/locales: the order in which locale fragments are accumulated
  1804 has changed.  This enables to override declarations from fragments due
  1805 to interpretations -- for example, unwanted simp rules.
  1806 
  1807 * Isar/locales: interpretation in theories and proof contexts has been
  1808 extended.  One may now specify (and prove) equations, which are
  1809 unfolded in interpreted theorems.  This is useful for replacing
  1810 defined concepts (constants depending on locale parameters) by
  1811 concepts already existing in the target context.  Example:
  1812 
  1813   interpretation partial_order ["op <= :: [int, int] => bool"]
  1814     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1815 
  1816 Typically, the constant `partial_order.less' is created by a
  1817 definition specification element in the context of locale
  1818 partial_order.
  1819 
  1820 * Method "induct": improved internal context management to support
  1821 local fixes and defines on-the-fly. Thus explicit meta-level
  1822 connectives !!  and ==> are rarely required anymore in inductive goals
  1823 (using object-logic connectives for this purpose has been long
  1824 obsolete anyway). Common proof patterns are explained in
  1825 src/HOL/Induct/Common_Patterns.thy, see also
  1826 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1827 examples.
  1828 
  1829 * Method "induct": improved handling of simultaneous goals. Instead of
  1830 introducing object-level conjunction, the statement is now split into
  1831 several conclusions, while the corresponding symbolic cases are nested
  1832 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1833 see src/HOL/Induct/Common_Patterns.thy, for example.
  1834 
  1835 * Method "induct": mutual induction rules are now specified as a list
  1836 of rule sharing the same induction cases. HOL packages usually provide
  1837 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1838 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1839 mutual induction rules differently, i.e. like this:
  1840 
  1841   (induct rule: foo_bar.inducts)
  1842   (induct set: foo bar)
  1843   (induct pred: foo bar)
  1844   (induct type: foo bar)
  1845 
  1846 The ML function ProjectRule.projections turns old-style rules into the
  1847 new format.
  1848 
  1849 * Method "coinduct": dual of induction, see
  1850 src/HOL/Library/Coinductive_List.thy for various examples.
  1851 
  1852 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1853 considered a legacy feature.
  1854 
  1855 * Attribute "symmetric" produces result with standardized schematic
  1856 variables (index 0).  Potential INCOMPATIBILITY.
  1857 
  1858 * Simplifier: by default the simplifier trace only shows top level
  1859 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1860 default. Thus there is less danger of being flooded by the trace. The
  1861 trace indicates where parts have been suppressed.
  1862   
  1863 * Provers/classical: removed obsolete classical version of elim_format
  1864 attribute; classical elim/dest rules are now treated uniformly when
  1865 manipulating the claset.
  1866 
  1867 * Provers/classical: stricter checks to ensure that supplied intro,
  1868 dest and elim rules are well-formed; dest and elim rules must have at
  1869 least one premise.
  1870 
  1871 * Provers/classical: attributes dest/elim/intro take an optional
  1872 weight argument for the rule (just as the Pure versions).  Weights are
  1873 ignored by automated tools, but determine the search order of single
  1874 rule steps.
  1875 
  1876 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1877 where the body does not mention the bound variable.  Note that dummy
  1878 patterns implicitly depend on their context of bounds, which makes
  1879 "{_. _}" match any set comprehension as expected.  Potential
  1880 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1881 constant "_idtdummy" in the binding position.
  1882 
  1883 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1884 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1885 for example "A -> B" => "Pi A (%_. B)".
  1886 
  1887 * Pure: 'class_deps' command visualizes the subclass relation, using
  1888 the graph browser tool.
  1889 
  1890 * Pure: 'print_theory' now suppresses certain internal declarations by
  1891 default; use '!' option for full details.
  1892 
  1893 
  1894 *** HOL ***
  1895 
  1896 * Method "metis" proves goals by applying the Metis general-purpose
  1897 resolution prover (see also http://gilith.com/software/metis/).
  1898 Examples are in the directory MetisExamples.  WARNING: the
  1899 Isabelle/HOL-Metis integration does not yet work properly with
  1900 multi-threading.
  1901   
  1902 * Command 'sledgehammer' invokes external automatic theorem provers as
  1903 background processes.  It generates calls to the "metis" method if
  1904 successful. These can be pasted into the proof.  Users do not have to
  1905 wait for the automatic provers to return.  WARNING: does not really
  1906 work with multi-threading.
  1907 
  1908 * New "auto_quickcheck" feature tests outermost goal statements for
  1909 potential counter-examples.  Controlled by ML references
  1910 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1911 5000 milliseconds).  Fails silently if statements is outside of
  1912 executable fragment, or any other codgenerator problem occurs.
  1913 
  1914 * New constant "undefined" with axiom "undefined x = undefined".
  1915 
  1916 * Added class "HOL.eq", allowing for code generation with polymorphic
  1917 equality.
  1918 
  1919 * Some renaming of class constants due to canonical name prefixing in
  1920 the new 'class' package:
  1921 
  1922     HOL.abs ~> HOL.abs_class.abs
  1923     HOL.divide ~> HOL.divide_class.divide
  1924     0 ~> HOL.zero_class.zero
  1925     1 ~> HOL.one_class.one
  1926     op + ~> HOL.plus_class.plus
  1927     op - ~> HOL.minus_class.minus
  1928     uminus ~> HOL.minus_class.uminus
  1929     op * ~> HOL.times_class.times
  1930     op < ~> HOL.ord_class.less
  1931     op <= > HOL.ord_class.less_eq
  1932     Nat.power ~> Power.power_class.power
  1933     Nat.size ~> Nat.size_class.size
  1934     Numeral.number_of ~> Numeral.number_class.number_of
  1935     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1936     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1937     Orderings.min ~> Orderings.ord_class.min
  1938     Orderings.max ~> Orderings.ord_class.max
  1939     Divides.op div ~> Divides.div_class.div
  1940     Divides.op mod ~> Divides.div_class.mod
  1941     Divides.op dvd ~> Divides.div_class.dvd
  1942 
  1943 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1944 
  1945 a) User-defined constants using any of the names "plus", "minus",
  1946 "times", "less" or "less_eq". The standard syntax translations for
  1947 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1948 names.
  1949 
  1950 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1951 INCOMPATIBILITY: use more specific names.
  1952 
  1953 c) Permutative equations (e.g. "a + b = b + a")
  1954 Since the change of names also changes the order of terms, permutative
  1955 rewrite rules may get applied in a different order. Experience shows
  1956 that this is rarely the case (only two adaptions in the whole Isabelle
  1957 distribution).  INCOMPATIBILITY: rewrite proofs
  1958 
  1959 d) ML code directly refering to constant names
  1960 This in general only affects hand-written proof tactics, simprocs and
  1961 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1962 Consider using @{const_name} antiquotation.
  1963 
  1964 * New class "default" with associated constant "default".
  1965 
  1966 * Function "sgn" is now overloaded and available on int, real, complex
  1967 (and other numeric types), using class "sgn".  Two possible defs of
  1968 sgn are given as equational assumptions in the classes sgn_if and
  1969 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1970 INCOMPATIBILITY.
  1971 
  1972 * Locale "partial_order" now unified with class "order" (cf. theory
  1973 Orderings), added parameter "less".  INCOMPATIBILITY.
  1974 
  1975 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1976 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1977 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1978 
  1979 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1980 changed order of proof goals in instance proofs.
  1981 
  1982 * The transitivity reasoner for partial and linear orders is set up
  1983 for classes "order" and "linorder".  Instances of the reasoner are available
  1984 in all contexts importing or interpreting the corresponding locales.
  1985 Method "order" invokes the reasoner separately; the reasoner
  1986 is also integrated with the Simplifier as a solver.  Diagnostic
  1987 command 'print_orders' shows the available instances of the reasoner
  1988 in the current context.
  1989 
  1990 * Localized monotonicity predicate in theory "Orderings"; integrated
  1991 lemmas max_of_mono and min_of_mono with this predicate.
  1992 INCOMPATIBILITY.
  1993 
  1994 * Formulation of theorem "dense" changed slightly due to integration
  1995 with new class dense_linear_order.
  1996 
  1997 * Uniform lattice theory development in HOL.
  1998 
  1999     constants "meet" and "join" now named "inf" and "sup"
  2000     constant "Meet" now named "Inf"
  2001 
  2002     classes "meet_semilorder" and "join_semilorder" now named
  2003       "lower_semilattice" and "upper_semilattice"
  2004     class "lorder" now named "lattice"
  2005     class "comp_lat" now named "complete_lattice"
  2006 
  2007     Instantiation of lattice classes allows explicit definitions
  2008     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  2009 
  2010   INCOMPATIBILITY.  Theorem renames:
  2011 
  2012     meet_left_le            ~> inf_le1
  2013     meet_right_le           ~> inf_le2
  2014     join_left_le            ~> sup_ge1
  2015     join_right_le           ~> sup_ge2
  2016     meet_join_le            ~> inf_sup_ord
  2017     le_meetI                ~> le_infI
  2018     join_leI                ~> le_supI
  2019     le_meet                 ~> le_inf_iff
  2020     le_join                 ~> ge_sup_conv
  2021     meet_idempotent         ~> inf_idem
  2022     join_idempotent         ~> sup_idem
  2023     meet_comm               ~> inf_commute
  2024     join_comm               ~> sup_commute
  2025     meet_leI1               ~> le_infI1
  2026     meet_leI2               ~> le_infI2
  2027     le_joinI1               ~> le_supI1
  2028     le_joinI2               ~> le_supI2
  2029     meet_assoc              ~> inf_assoc
  2030     join_assoc              ~> sup_assoc
  2031     meet_left_comm          ~> inf_left_commute
  2032     meet_left_idempotent    ~> inf_left_idem
  2033     join_left_comm          ~> sup_left_commute
  2034     join_left_idempotent    ~> sup_left_idem
  2035     meet_aci                ~> inf_aci
  2036     join_aci                ~> sup_aci
  2037     le_def_meet             ~> le_iff_inf
  2038     le_def_join             ~> le_iff_sup
  2039     join_absorp2            ~> sup_absorb2
  2040     join_absorp1            ~> sup_absorb1
  2041     meet_absorp1            ~> inf_absorb1
  2042     meet_absorp2            ~> inf_absorb2
  2043     meet_join_absorp        ~> inf_sup_absorb
  2044     join_meet_absorp        ~> sup_inf_absorb
  2045     distrib_join_le         ~> distrib_sup_le
  2046     distrib_meet_le         ~> distrib_inf_le
  2047 
  2048     add_meet_distrib_left   ~> add_inf_distrib_left
  2049     add_join_distrib_left   ~> add_sup_distrib_left
  2050     is_join_neg_meet        ~> is_join_neg_inf
  2051     is_meet_neg_join        ~> is_meet_neg_sup
  2052     add_meet_distrib_right  ~> add_inf_distrib_right
  2053     add_join_distrib_right  ~> add_sup_distrib_right
  2054     add_meet_join_distribs  ~> add_sup_inf_distribs
  2055     join_eq_neg_meet        ~> sup_eq_neg_inf
  2056     meet_eq_neg_join        ~> inf_eq_neg_sup
  2057     add_eq_meet_join        ~> add_eq_inf_sup
  2058     meet_0_imp_0            ~> inf_0_imp_0
  2059     join_0_imp_0            ~> sup_0_imp_0
  2060     meet_0_eq_0             ~> inf_0_eq_0
  2061     join_0_eq_0             ~> sup_0_eq_0
  2062     neg_meet_eq_join        ~> neg_inf_eq_sup
  2063     neg_join_eq_meet        ~> neg_sup_eq_inf
  2064     join_eq_if              ~> sup_eq_if
  2065 
  2066     mono_meet               ~> mono_inf
  2067     mono_join               ~> mono_sup
  2068     meet_bool_eq            ~> inf_bool_eq
  2069     join_bool_eq            ~> sup_bool_eq
  2070     meet_fun_eq             ~> inf_fun_eq
  2071     join_fun_eq             ~> sup_fun_eq
  2072     meet_set_eq             ~> inf_set_eq
  2073     join_set_eq             ~> sup_set_eq
  2074     meet1_iff               ~> inf1_iff
  2075     meet2_iff               ~> inf2_iff
  2076     meet1I                  ~> inf1I
  2077     meet2I                  ~> inf2I
  2078     meet1D1                 ~> inf1D1
  2079     meet2D1                 ~> inf2D1
  2080     meet1D2                 ~> inf1D2
  2081     meet2D2                 ~> inf2D2
  2082     meet1E                  ~> inf1E
  2083     meet2E                  ~> inf2E
  2084     join1_iff               ~> sup1_iff
  2085     join2_iff               ~> sup2_iff
  2086     join1I1                 ~> sup1I1
  2087     join2I1                 ~> sup2I1
  2088     join1I1                 ~> sup1I1
  2089     join2I2                 ~> sup1I2
  2090     join1CI                 ~> sup1CI
  2091     join2CI                 ~> sup2CI
  2092     join1E                  ~> sup1E
  2093     join2E                  ~> sup2E
  2094 
  2095     is_meet_Meet            ~> is_meet_Inf
  2096     Meet_bool_def           ~> Inf_bool_def
  2097     Meet_fun_def            ~> Inf_fun_def
  2098     Meet_greatest           ~> Inf_greatest
  2099     Meet_lower              ~> Inf_lower
  2100     Meet_set_def            ~> Inf_set_def
  2101 
  2102     Sup_def                 ~> Sup_Inf
  2103     Sup_bool_eq             ~> Sup_bool_def
  2104     Sup_fun_eq              ~> Sup_fun_def
  2105     Sup_set_eq              ~> Sup_set_def
  2106 
  2107     listsp_meetI            ~> listsp_infI
  2108     listsp_meet_eq          ~> listsp_inf_eq
  2109 
  2110     meet_min                ~> inf_min
  2111     join_max                ~> sup_max
  2112 
  2113 * Added syntactic class "size"; overloaded constant "size" now has
  2114 type "'a::size ==> bool"
  2115 
  2116 * Internal reorganisation of `size' of datatypes: size theorems
  2117 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2118 simplification rules by default!); theorems "prod.size" now named
  2119 "*.size".
  2120 
  2121 * Class "div" now inherits from class "times" rather than "type".
  2122 INCOMPATIBILITY.
  2123 
  2124 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2125 Linorder etc.  have disappeared; operations defined in terms of
  2126 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2127 
  2128 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2129 
  2130 * HOL-Word: New extensive library and type for generic, fixed size
  2131 machine words, with arithemtic, bit-wise, shifting and rotating
  2132 operations, reflection into int, nat, and bool lists, automation for
  2133 linear arithmetic (by automatic reflection into nat or int), including
  2134 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2135 arithmetic type classes, supporting automatic simplification of
  2136 numerals on all operations.
  2137 
  2138 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2139 
  2140 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2141 
  2142 * Code generator library theories:
  2143   - Code_Integer represents HOL integers by big integer literals in target
  2144     languages.
  2145   - Code_Char represents HOL characters by character literals in target
  2146     languages.
  2147   - Code_Char_chr like Code_Char, but also offers treatment of character
  2148     codes; includes Code_Integer.
  2149   - Executable_Set allows to generate code for finite sets using lists.
  2150   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2151     denominator).
  2152   - Executable_Real implements a subset of real numbers, namly those
  2153     representable by rational numbers.
  2154   - Efficient_Nat implements natural numbers by integers, which in general will
  2155     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2156     includes Code_Integer.
  2157   - Code_Index provides an additional datatype index which is mapped to
  2158     target-language built-in integers.
  2159   - Code_Message provides an additional datatype message_string which is isomorphic to
  2160     strings; messages are mapped to target-language strings.
  2161 
  2162 * New package for inductive predicates
  2163 
  2164   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2165 
  2166     inductive
  2167       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2168       for z_1 :: U_1 and ... and z_n :: U_m
  2169     where
  2170       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2171     | ...
  2172 
  2173   with full support for type-inference, rather than
  2174 
  2175     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2176 
  2177     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2178     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2179 
  2180     inductive "s z_1 ... z_m"
  2181     intros
  2182       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2183       ...
  2184 
  2185   For backward compatibility, there is a wrapper allowing inductive
  2186   sets to be defined with the new package via
  2187 
  2188     inductive_set
  2189       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2190       for z_1 :: U_1 and ... and z_n :: U_m
  2191     where
  2192       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2193     | ...
  2194 
  2195   or
  2196 
  2197     inductive_set
  2198       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2199       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2200       for z_1 :: U_1 and ... and z_n :: U_m
  2201     where
  2202       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2203     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2204     | ...
  2205 
  2206   if the additional syntax "p ..." is required.
  2207 
  2208   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2209   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2210 
  2211   INCOMPATIBILITIES:
  2212 
  2213   - Since declaration and definition of inductive sets or predicates
  2214     is no longer separated, abbreviations involving the newly
  2215     introduced sets or predicates must be specified together with the
  2216     introduction rules after the 'where' keyword (see above), rather
  2217     than before the actual inductive definition.
  2218 
  2219   - The variables in induction and elimination rules are now
  2220     quantified in the order of their occurrence in the introduction
  2221     rules, rather than in alphabetical order. Since this may break
  2222     some proofs, these proofs either have to be repaired, e.g. by
  2223     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2224     statements of the form
  2225 
  2226       case (rule_i a_i_1 ... a_i_{k_i})
  2227 
  2228     or the old order of quantification has to be restored by explicitly adding
  2229     meta-level quantifiers in the introduction rules, i.e.
  2230 
  2231       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2232 
  2233   - The format of the elimination rules is now
  2234 
  2235       p z_1 ... z_m x_1 ... x_n ==>
  2236         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2237         ==> ... ==> P
  2238 
  2239     for predicates and
  2240 
  2241       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2242         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2243         ==> ... ==> P
  2244 
  2245     for sets rather than
  2246 
  2247       x : s z_1 ... z_m ==>
  2248         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2249         ==> ... ==> P
  2250 
  2251     This may require terms in goals to be expanded to n-tuples
  2252     (e.g. using case_tac or simplification with the split_paired_all
  2253     rule) before the above elimination rule is applicable.
  2254 
  2255   - The elimination or case analysis rules for (mutually) inductive
  2256     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2257     list of rules "p_1_..._p_k.elims" is no longer available.
  2258 
  2259 * New package "function"/"fun" for general recursive functions,
  2260 supporting mutual and nested recursion, definitions in local contexts,
  2261 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2262 for small examples, and the separate tutorial on the function
  2263 package. The old recdef "package" is still available as before, but
  2264 users are encouraged to use the new package.
  2265 
  2266 * Method "lexicographic_order" automatically synthesizes termination
  2267 relations as lexicographic combinations of size measures. 
  2268 
  2269 * Case-expressions allow arbitrary constructor-patterns (including
  2270 "_") and take their order into account, like in functional
  2271 programming.  Internally, this is translated into nested
  2272 case-expressions; missing cases are added and mapped to the predefined
  2273 constant "undefined". In complicated cases printing may no longer show
  2274 the original input but the internal form. Lambda-abstractions allow
  2275 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2276 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2277 variable.
  2278 
  2279 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2280 is an abbreviation for "of_nat :: nat => int". The simplification
  2281 rules for "of_nat" have been changed to work like "int" did
  2282 previously.  Potential INCOMPATIBILITY:
  2283   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2284   - of_nat_diff and of_nat_mult are no longer default simp rules
  2285 
  2286 * Method "algebra" solves polynomial equations over (semi)rings using
  2287 Groebner bases. The (semi)ring structure is defined by locales and the
  2288 tool setup depends on that generic context. Installing the method for
  2289 a specific type involves instantiating the locale and possibly adding
  2290 declarations for computation on the coefficients.  The method is
  2291 already instantiated for natural numbers and for the axiomatic class
  2292 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2293 CALCULEMUS 2007 for the general principles underlying this
  2294 architecture of context-aware proof-tools.
  2295 
  2296 * Method "ferrack" implements quantifier elimination over
  2297 special-purpose dense linear orders using locales (analogous to
  2298 "algebra"). The method is already installed for class
  2299 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2300 rat, etc.
  2301 
  2302 * Former constant "List.op @" now named "List.append".  Use ML
  2303 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2304 circumvent possible incompatibilities when working on ML level.
  2305 
  2306 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2307 
  2308 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2309 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2310 
  2311 * New syntax for Haskell-like list comprehension (input only), eg.
  2312 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2313 
  2314 * The special syntax for function "filter" has changed from [x :
  2315 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2316 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2317 
  2318 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2319 defined on nat only, as an abbreviation for [a..<Suc b]
  2320 INCOMPATIBILITY.
  2321 
  2322 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2323 
  2324 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2325 
  2326 * New lemma collection field_simps (an extension of ring_simps) for
  2327 manipulating (in)equations involving division. Multiplies with all
  2328 denominators that can be proved to be non-zero (in equations) or
  2329 positive/negative (in inequations).
  2330 
  2331 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2332 have been improved and renamed to ring_simps, group_simps and
  2333 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2334 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2335 
  2336 * Theory Library/Commutative_Ring: switched from recdef to function
  2337 package; constants add, mul, pow now curried.  Infix syntax for
  2338 algebraic operations.
  2339 
  2340 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2341 INCOMPATIBILITY.
  2342 
  2343 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2344 INCOMPATIBILITY.
  2345 
  2346 * HOL/records: generalised field-update to take a function on the
  2347 field rather than the new value: r(|A := x|) is translated to A_update
  2348 (K x) r The K-combinator that is internally used is called K_record.
  2349 INCOMPATIBILITY: Usage of the plain update functions has to be
  2350 adapted.
  2351  
  2352 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2353 * x = 0, which are required for a semiring.  Richer structures do not
  2354 inherit from semiring_0 anymore, because this property is a theorem
  2355 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2356 there is more to prove, but this is mostly trivial.
  2357 
  2358 * Class "recpower" is generalized to arbitrary monoids, not just
  2359 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2360 commutativity or semiring properties additionally.
  2361 
  2362 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2363 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2364 better use 'abbreviation'.
  2365 
  2366 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2367 
  2368 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2369 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2370 significant changes for setting up numeral syntax for types:
  2371   - New constants Numeral.pred and Numeral.succ instead
  2372       of former Numeral.bin_pred and Numeral.bin_succ.
  2373   - Use integer operations instead of bin_add, bin_mult and so on.
  2374   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2375   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2376 
  2377 See src/HOL/Integ/IntArith.thy for an example setup.
  2378 
  2379 * Command 'normal_form' computes the normal form of a term that may
  2380 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2381 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2382 heavy-duty computations because the functions are compiled to ML
  2383 first.  Correspondingly, a method "normalization" is provided.  See
  2384 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2385 
  2386 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2387 25 like -->); output depends on the "iff" print_mode, the default is
  2388 "A = B" (with priority 50).
  2389 
  2390 * Relations less (<) and less_eq (<=) are also available on type bool.
  2391 Modified syntax to disallow nesting without explicit parentheses,
  2392 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2393 INCOMPATIBILITY.
  2394 
  2395 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2396 
  2397 * Relation composition operator "op O" now has precedence 75 and binds
  2398 stronger than union and intersection. INCOMPATIBILITY.
  2399 
  2400 * The old set interval syntax "{m..n(}" (and relatives) has been
  2401 removed.  Use "{m..<n}" (and relatives) instead.
  2402 
  2403 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2404 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2405 ``declare [[simproc del: neq]]''.
  2406 
  2407 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2408 True/False.
  2409 
  2410 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2411 
  2412 * Theorem setsum_mult renamed to setsum_right_distrib.
  2413 
  2414 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2415 ``rule'' method.
  2416 
  2417 * Reimplemented methods "sat" and "satx", with several improvements:
  2418 goals no longer need to be stated as "<prems> ==> False", equivalences
  2419 (i.e. "=" on type bool) are handled, variable names of the form
  2420 "lit_<n>" are no longer reserved, significant speedup.
  2421 
  2422 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2423 zChaff is still supported as well.
  2424 
  2425 * 'inductive' and 'datatype': provide projections of mutual rules,
  2426 bundled as foo_bar.inducts;
  2427 
  2428 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2429 Library.
  2430 
  2431 * Library: moved theory Accessible_Part to main HOL.
  2432 
  2433 * Library: added theory Coinductive_List of potentially infinite lists
  2434 as greatest fixed-point.
  2435 
  2436 * Library: added theory AssocList which implements (finite) maps as
  2437 association lists.
  2438 
  2439 * Method "evaluation" solves goals (i.e. a boolean expression)
  2440 efficiently by compiling it to ML.  The goal is "proved" (via an
  2441 oracle) if it evaluates to True.
  2442 
  2443 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2444 also when invoked by the simplifier.  This results in the Simplifier
  2445 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2446 Configuration option fast_arith_split_limit=0 recovers the old
  2447 behavior.
  2448 
  2449 * Support for hex (0x20) and binary (0b1001) numerals.
  2450 
  2451 * New method: reify eqs (t), where eqs are equations for an
  2452 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2453 parameter, computes a term s::'b and a list xs::'a list and proves the
  2454 theorem I xs s = t. This is also known as reification or quoting. The
  2455 resulting theorem is applied to the subgoal to substitute t with I xs
  2456 s.  If t is omitted, the subgoal itself is reified.
  2457 
  2458 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2459 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2460 where f is supposed to be a computable function (in the sense of code
  2461 generattion). The method uses reify to compute s and xs as above then
  2462 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2463 r and finally gets the theorem t = r, which is again applied to the
  2464 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2465 
  2466 * Reflection: Automatic reification now handels binding, an example is
  2467 available in src/HOL/ex/ReflectionEx.thy
  2468 
  2469 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2470 command 'statespace' that is similar to 'record', but introduces an
  2471 abstract specification based on the locale infrastructure instead of
  2472 HOL types.  This leads to extra flexibility in composing state spaces,
  2473 in particular multiple inheritance and renaming of components.
  2474 
  2475 
  2476 *** HOL-Complex ***
  2477 
  2478 * Hyperreal: Functions root and sqrt are now defined on negative real
  2479 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2480 Nonnegativity side conditions have been removed from many lemmas, so
  2481 that more subgoals may now be solved by simplification; potential
  2482 INCOMPATIBILITY.
  2483 
  2484 * Real: new type classes formalize real normed vector spaces and
  2485 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2486 and norm :: 'a => real.
  2487 
  2488 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2489 reals into other types. The overloaded constant Reals :: 'a set is now
  2490 defined as range of_real; potential INCOMPATIBILITY.
  2491 
  2492 * Real: proper support for ML code generation, including 'quickcheck'.
  2493 Reals are implemented as arbitrary precision rationals.
  2494 
  2495 * Hyperreal: Several constants that previously worked only for the
  2496 reals have been generalized, so they now work over arbitrary vector
  2497 spaces. Type annotations may need to be added in some cases; potential
  2498 INCOMPATIBILITY.
  2499 
  2500   Infinitesimal  :: ('a::real_normed_vector) star set
  2501   HFinite        :: ('a::real_normed_vector) star set
  2502   HInfinite      :: ('a::real_normed_vector) star set
  2503   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2504   monad          :: ('a::real_normed_vector) star => 'a star set
  2505   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2506   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2507   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2508   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2509   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2510   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2511   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2512   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2513   sgn            :: 'a::real_normed_vector => 'a
  2514   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2515 
  2516 * Complex: Some complex-specific constants are now abbreviations for
  2517 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2518 hnorm.  Other constants have been entirely removed in favor of the
  2519 polymorphic versions (INCOMPATIBILITY):
  2520 
  2521   approx        <-- capprox
  2522   HFinite       <-- CFinite
  2523   HInfinite     <-- CInfinite
  2524   Infinitesimal <-- CInfinitesimal
  2525   monad         <-- cmonad
  2526   galaxy        <-- cgalaxy
  2527   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2528   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2529   (ns)deriv     <-- (ns)cderiv
  2530 
  2531 
  2532 *** HOL-Algebra ***
  2533 
  2534 * Formalisation of ideals and the quotient construction over rings.
  2535 
  2536 * Order and lattice theory no longer based on records.
  2537 INCOMPATIBILITY.
  2538 
  2539 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2540 greatest_closed.  INCOMPATIBILITY.
  2541 
  2542 * Method algebra is now set up via an attribute.  For examples see
  2543 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2544 of algebraic structures.
  2545 
  2546 * Renamed theory CRing to Ring.
  2547 
  2548 
  2549 *** HOL-Nominal ***
  2550 
  2551 * Substantial, yet incomplete support for nominal datatypes (binding
  2552 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2553 src/HOL/Nominal/Examples.  Prospective users should consult
  2554 http://isabelle.in.tum.de/nominal/
  2555 
  2556 
  2557 *** ML ***
  2558 
  2559 * ML basics: just one true type int, which coincides with IntInf.int
  2560 (even on SML/NJ).
  2561 
  2562 * ML within Isar: antiquotations allow to embed statically-checked
  2563 formal entities in the source, referring to the context available at
  2564 compile-time.  For example:
  2565 
  2566 ML {* @{sort "{zero,one}"} *}
  2567 ML {* @{typ "'a => 'b"} *}
  2568 ML {* @{term "%x. x"} *}
  2569 ML {* @{prop "x == y"} *}
  2570 ML {* @{ctyp "'a => 'b"} *}
  2571 ML {* @{cterm "%x. x"} *}
  2572 ML {* @{cprop "x == y"} *}
  2573 ML {* @{thm asm_rl} *}
  2574 ML {* @{thms asm_rl} *}
  2575 ML {* @{type_name c} *}
  2576 ML {* @{type_syntax c} *}
  2577 ML {* @{const_name c} *}
  2578 ML {* @{const_syntax c} *}
  2579 ML {* @{context} *}
  2580 ML {* @{theory} *}
  2581 ML {* @{theory Pure} *}
  2582 ML {* @{theory_ref} *}
  2583 ML {* @{theory_ref Pure} *}
  2584 ML {* @{simpset} *}
  2585 ML {* @{claset} *}
  2586 ML {* @{clasimpset} *}
  2587 
  2588 The same works for sources being ``used'' within an Isar context.
  2589 
  2590 * ML in Isar: improved error reporting; extra verbosity with
  2591 ML_Context.trace enabled.
  2592 
  2593 * Pure/General/table.ML: the join operations now works via exceptions
  2594 DUP/SAME instead of type option. This is simpler in simple cases, and
  2595 admits slightly more efficient complex applications.
  2596 
  2597 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2598 use Context.generic instead of just theory.
  2599 
  2600 * Pure: datatype Context.generic joins theory/Proof.context and
  2601 provides some facilities for code that works in either kind of
  2602 context, notably GenericDataFun for uniform theory and proof data.
  2603 
  2604 * Pure: simplified internal attribute type, which is now always
  2605 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2606 local (Proof.context) attributes have been discontinued, while
  2607 minimizing code duplication. Thm.rule_attribute and
  2608 Thm.declaration_attribute build canonical attributes; see also structure
  2609 Context for further operations on Context.generic, notably
  2610 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2611 declarations and definitions.
  2612 
  2613 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2614 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2615 init only required for impure data. INCOMPATIBILITY: empty really need
  2616 to be empty (no dependencies on theory content!)
  2617 
  2618 * Pure/kernel: consts certification ignores sort constraints given in
  2619 signature declarations. (This information is not relevant to the
  2620 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2621 potential INCOMPATIBILITY.
  2622 
  2623 * Pure: axiomatic type classes are now purely definitional, with
  2624 explicit proofs of class axioms and super class relations performed
  2625 internally. See Pure/axclass.ML for the main internal interfaces --
  2626 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2627 AxClass.axiomatize_class/classrel/arity supersede
  2628 Sign.add_classes/classrel/arities.
  2629 
  2630 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2631 global/local versions on theory vs. Proof.context have been
  2632 discontinued; Attrib.syntax and Method.syntax have been adapted
  2633 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2634 attributes, methods, etc.
  2635 
  2636 * Pure: several functions of signature "... -> theory -> theory * ..."
  2637 have been reoriented to "... -> theory -> ... * theory" in order to
  2638 allow natural usage in combination with the ||>, ||>>, |-> and
  2639 fold_map combinators.
  2640 
  2641 * Pure: official theorem names (closed derivations) and additional
  2642 comments (tags) are now strictly separate.  Name hints -- which are
  2643 maintained as tags -- may be attached any time without affecting the
  2644 derivation.
  2645 
  2646 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2647 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2648 achieve the old behaviour.
  2649 
  2650 * Pure: the "Goal" constant is now called "prop", supporting a
  2651 slightly more general idea of ``protecting'' meta-level rule
  2652 statements.
  2653 
  2654 * Pure: Logic.(un)varify only works in a global context, which is now
  2655 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2656 Logic.legacy_(un)varify as temporary workaround.
  2657 
  2658 * Pure: structure Name provides scalable operations for generating
  2659 internal variable names, notably Name.variants etc.  This replaces
  2660 some popular functions from term.ML:
  2661 
  2662   Term.variant		->  Name.variant
  2663   Term.variantlist	->  Name.variant_list
  2664   Term.invent_names	->  Name.invent_list
  2665 
  2666 Note that low-level renaming rarely occurs in new code -- operations
  2667 from structure Variable are used instead (see below).
  2668 
  2669 * Pure: structure Variable provides fundamental operations for proper
  2670 treatment of fixed/schematic variables in a context.  For example,
  2671 Variable.import introduces fixes for schematics of given facts and
  2672 Variable.export reverses the effect (up to renaming) -- this replaces
  2673 various freeze_thaw operations.
  2674 
  2675 * Pure: structure Goal provides simple interfaces for
  2676 init/conclude/finish and tactical prove operations (replacing former
  2677 Tactic.prove).  Goal.prove is the canonical way to prove results
  2678 within a given context; Goal.prove_global is a degraded version for
  2679 theory level goals, including a global Drule.standard.  Note that
  2680 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2681 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2682 in a locale context).
  2683 
  2684 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2685 and type checking (Syntax.check_term etc.), with common combinations
  2686 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2687 which are considered legacy and await removal.
  2688 
  2689 * Pure/Syntax: generic interfaces for type unchecking
  2690 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2691 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2692 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2693 available for convenience, but refer to the very same operations using
  2694 a mere theory instead of a full context.
  2695 
  2696 * Isar: simplified treatment of user-level errors, using exception
  2697 ERROR of string uniformly.  Function error now merely raises ERROR,
  2698 without any side effect on output channels.  The Isar toplevel takes
  2699 care of proper display of ERROR exceptions.  ML code may use plain
  2700 handle/can/try; cat_error may be used to concatenate errors like this:
  2701 
  2702   ... handle ERROR msg => cat_error msg "..."
  2703 
  2704 Toplevel ML code (run directly or through the Isar toplevel) may be
  2705 embedded into the Isar toplevel with exception display/debug like
  2706 this:
  2707 
  2708   Isar.toplevel (fn () => ...)
  2709 
  2710 INCOMPATIBILITY, removed special transform_error facilities, removed
  2711 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2712 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2713 -- use plain ERROR instead.
  2714 
  2715 * Isar: theory setup now has type (theory -> theory), instead of a
  2716 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2717 
  2718 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2719 ProofContext.debug/verbose flags.
  2720 
  2721 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2722 theory before entering a proof state.  Transactions now always see a
  2723 quasi-functional intermediate checkpoint, both in interactive and
  2724 batch mode.
  2725 
  2726 * Isar: simplified interfaces for outer syntax.  Renamed
  2727 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2728 OuterSyntax.add_parsers -- this functionality is now included in
  2729 OuterSyntax.command etc.  INCOMPATIBILITY.
  2730 
  2731 * Simplifier: the simpset of a running simplification process now
  2732 contains a proof context (cf. Simplifier.the_context), which is the
  2733 very context that the initial simpset has been retrieved from (by
  2734 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2735 (solver, looper etc.) may depend on arbitrary proof data.
  2736 
  2737 * Simplifier.inherit_context inherits the proof context (plus the
  2738 local bounds) of the current simplification process; any simproc
  2739 etc. that calls the Simplifier recursively should do this!  Removed
  2740 former Simplifier.inherit_bounds, which is already included here --
  2741 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2742 specify an explicit context using Simplifier.context/theory_context.
  2743 
  2744 * Simplifier/Classical Reasoner: more abstract interfaces
  2745 change_simpset/claset for modifying the simpset/claset reference of a
  2746 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2747 INCOMPATIBILITY.
  2748 
  2749 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2750 "Trueprop" etc.
  2751 
  2752 
  2753 *** System ***
  2754 
  2755 * settings: the default heap location within ISABELLE_HOME_USER now
  2756 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2757 Isabelle installations.
  2758 
  2759 * isabelle-process: option -S (secure mode) disables some critical
  2760 operations, notably runtime compilation and evaluation of ML source
  2761 code.
  2762 
  2763 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2764 
  2765 * Support for parallel execution, using native multicore support of
  2766 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2767 independent theories, according to the given theory header
  2768 specifications. The maximum number of worker threads is specified via
  2769 usedir option -M or the "max-threads" setting in Proof General. A
  2770 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2771 to 6 on a 8-core machine.  User-code needs to observe certain
  2772 guidelines for thread-safe programming, see appendix A in the Isar
  2773 Implementation manual.
  2774 
  2775 
  2776 
  2777 New in Isabelle2005 (October 2005)
  2778 ----------------------------------
  2779 
  2780 *** General ***
  2781 
  2782 * Theory headers: the new header syntax for Isar theories is
  2783 
  2784   theory <name>
  2785   imports <theory1> ... <theoryN>
  2786   uses <file1> ... <fileM>
  2787   begin
  2788 
  2789 where the 'uses' part is optional.  The previous syntax
  2790 
  2791   theory <name> = <theory1> + ... + <theoryN>:
  2792 
  2793 will disappear in the next release.  Use isatool fixheaders to convert
  2794 existing theory files.  Note that there is no change in ancient
  2795 non-Isar theories now, but these will disappear soon.
  2796 
  2797 * Theory loader: parent theories can now also be referred to via
  2798 relative and absolute paths.
  2799 
  2800 * Command 'find_theorems' searches for a list of criteria instead of a
  2801 list of constants. Known criteria are: intro, elim, dest, name:string,
  2802 simp:term, and any term. Criteria can be preceded by '-' to select
  2803 theorems that do not match. Intro, elim, dest select theorems that
  2804 match the current goal, name:s selects theorems whose fully qualified
  2805 name contain s, and simp:term selects all simplification rules whose
  2806 lhs match term.  Any other term is interpreted as pattern and selects
  2807 all theorems matching the pattern. Available in ProofGeneral under
  2808 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2809 
  2810   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2811 
  2812 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2813 matching the current goal as introduction rule and not having "HOL."
  2814 in their name (i.e. not being defined in theory HOL).
  2815 
  2816 * Command 'thms_containing' has been discontinued in favour of
  2817 'find_theorems'; INCOMPATIBILITY.
  2818 
  2819 * Communication with Proof General is now 8bit clean, which means that
  2820 Unicode text in UTF-8 encoding may be used within theory texts (both
  2821 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2822 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2823 
  2824   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2825   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2826 
  2827 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2828 Classical Reasoner.  Typical big applications run around 2 times
  2829 faster.
  2830 
  2831 
  2832 *** Document preparation ***
  2833 
  2834 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2835 of raw sources.  Only those symbols that do not require additional
  2836 LaTeX packages (depending on comments in isabellesym.sty) are
  2837 displayed properly, everything else is left verbatim.  isatool display
  2838 and isatool print are used as front ends (these are subject to the
  2839 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2840 
  2841 * Command tags control specific markup of certain regions of text,
  2842 notably folding and hiding.  Predefined tags include "theory" (for
  2843 theory begin and end), "proof" for proof commands, and "ML" for
  2844 commands involving ML code; the additional tags "visible" and
  2845 "invisible" are unused by default.  Users may give explicit tag
  2846 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2847 interpretation of tags is determined by the LaTeX job during document
  2848 preparation: see option -V of isatool usedir, or options -n and -t of
  2849 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2850 \isadroptag.
  2851 
  2852 Several document versions may be produced at the same time via isatool
  2853 usedir (the generated index.html will link all of them).  Typical
  2854 specifications include ''-V document=theory,proof,ML'' to present
  2855 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2856 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2857 these parts without any formal replacement text.  The Isabelle site
  2858 default settings produce ''document'' and ''outline'' versions as
  2859 specified above.
  2860 
  2861 * Several new antiquotations:
  2862 
  2863   @{term_type term} prints a term with its type annotated;
  2864 
  2865   @{typeof term} prints the type of a term;
  2866 
  2867   @{const const} is the same as @{term const}, but checks that the
  2868   argument is a known logical constant;
  2869 
  2870   @{term_style style term} and @{thm_style style thm} print a term or
  2871   theorem applying a "style" to it
  2872 
  2873   @{ML text}
  2874 
  2875 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2876 definitions, equations, inequations etc., 'concl' printing only the
  2877 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2878 to print the specified premise.  TermStyle.add_style provides an ML
  2879 interface for introducing further styles.  See also the "LaTeX Sugar"
  2880 document practical applications.  The ML antiquotation prints
  2881 type-checked ML expressions verbatim.
  2882 
  2883 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2884 and 'text' support optional locale specification '(in loc)', which
  2885 specifies the default context for interpreting antiquotations.  For
  2886 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2887 
  2888 * Option 'locale=NAME' of antiquotations specifies an alternative
  2889 context interpreting the subsequent argument.  For example: @{thm
  2890 [locale=lattice] inf_assoc}.
  2891 
  2892 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2893 a proof context.
  2894 
  2895 * Proper output of antiquotations for theory commands involving a
  2896 proof context (such as 'locale' or 'theorem (in loc) ...').
  2897 
  2898 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2899 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2900 
  2901 * isatool usedir: new option -C (default true) controls whether option
  2902 -D should include a copy of the original document directory; -C false
  2903 prevents unwanted effects such as copying of administrative CVS data.
  2904 
  2905 
  2906 *** Pure ***
  2907 
  2908 * Considerably improved version of 'constdefs' command.  Now performs
  2909 automatic type-inference of declared constants; additional support for
  2910 local structure declarations (cf. locales and HOL records), see also
  2911 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2912 sequential dependencies of definitions within a single 'constdefs'
  2913 section; moreover, the declared name needs to be an identifier.  If
  2914 all fails, consider to fall back on 'consts' and 'defs' separately.
  2915 
  2916 * Improved indexed syntax and implicit structures.  First of all,
  2917 indexed syntax provides a notational device for subscripted
  2918 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2919 expressions.  Secondly, in a local context with structure
  2920 declarations, number indexes \<^sub>n or the empty index (default
  2921 number 1) refer to a certain fixed variable implicitly; option
  2922 show_structs controls printing of implicit structures.  Typical
  2923 applications of these concepts involve record types and locales.
  2924 
  2925 * New command 'no_syntax' removes grammar declarations (and
  2926 translations) resulting from the given syntax specification, which is
  2927 interpreted in the same manner as for the 'syntax' command.
  2928 
  2929 * 'Advanced' translation functions (parse_translation etc.) may depend
  2930 on the signature of the theory context being presently used for
  2931 parsing/printing, see also isar-ref manual.
  2932 
  2933 * Improved 'oracle' command provides a type-safe interface to turn an
  2934 ML expression of type theory -> T -> term into a primitive rule of
  2935 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2936 is already included here); see also FOL/ex/IffExample.thy;
  2937 INCOMPATIBILITY.
  2938 
  2939 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2940 before); "cI" is no longer bound, use "c.intro" instead.
  2941 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2942 axclasses vs. locales.
  2943 
  2944 * Improved internal renaming of symbolic identifiers -- attach primes
  2945 instead of base 26 numbers.
  2946 
  2947 * New flag show_question_marks controls printing of leading question
  2948 marks in schematic variable names.
  2949 
  2950 * In schematic variable names, *any* symbol following \<^isub> or
  2951 \<^isup> is now treated as part of the base name.  For example, the
  2952 following works without printing of awkward ".0" indexes:
  2953 
  2954   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2955     by simp
  2956 
  2957 * Inner syntax includes (*(*nested*) comments*).
  2958 
  2959 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2960 annotations as "(00...)".
  2961 
  2962 * Clear separation of logical types and nonterminals, where the latter
  2963 may only occur in 'syntax' specifications or type abbreviations.
  2964 Before that distinction was only partially implemented via type class
  2965 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2966 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2967 exotic syntax specifications may require further adaption
  2968 (e.g. Cube/Cube.thy).
  2969 
  2970 * Removed obsolete type class "logic", use the top sort {} instead.
  2971 Note that non-logical types should be declared as 'nonterminals'
  2972 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2973 specifications.
  2974 
  2975 * Attributes 'induct' and 'cases': type or set names may now be
  2976 locally fixed variables as well.
  2977 
  2978 * Simplifier: can now control the depth to which conditional rewriting
  2979 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2980 Limit.
  2981 
  2982 * Simplifier: simplification procedures may now take the current
  2983 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2984 interface), which is very useful for calling the Simplifier
  2985 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2986 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2987 low-level mk_simproc no longer applies Logic.varify internally, to
  2988 allow for use in a context of fixed variables.
  2989 
  2990 * thin_tac now works even if the assumption being deleted contains !!
  2991 or ==>.  More generally, erule now works even if the major premise of
  2992 the elimination rule contains !! or ==>.
  2993 
  2994 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2995 
  2996 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2997 from Pure, which contains all common declarations already.  Both
  2998 theories are defined via plain Isabelle/Isar .thy files.
  2999 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  3000 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  3001 use isatool fixcpure to adapt your theory and ML sources.
  3002 
  3003 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  3004 selections of theorems in named facts via index ranges.
  3005 
  3006 * 'print_theorems': in theory mode, really print the difference
  3007 wrt. the last state (works for interactive theory development only),
  3008 in proof mode print all local facts (cf. 'print_facts');
  3009 
  3010 * 'hide': option '(open)' hides only base names.
  3011 
  3012 * More efficient treatment of intermediate checkpoints in interactive
  3013 theory development.
  3014 
  3015 * Code generator is now invoked via code_module (incremental code
  3016 generation) and code_library (modular code generation, ML structures
  3017 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  3018 must be quoted when used as identifiers.
  3019 
  3020 * New 'value' command for reading, evaluating and printing terms using
  3021 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  3022 quoted when used as identifier.
  3023 
  3024 
  3025 *** Locales ***
  3026 
  3027 * New commands for the interpretation of locale expressions in
  3028 theories (1), locales (2) and proof contexts (3).  These generate
  3029 proof obligations from the expression specification.  After the
  3030 obligations have been discharged, theorems of the expression are added
  3031 to the theory, target locale or proof context.  The synopsis of the
  3032 commands is a follows:
  3033 
  3034   (1) interpretation expr inst
  3035   (2) interpretation target < expr
  3036   (3) interpret expr inst
  3037 
  3038 Interpretation in theories and proof contexts require a parameter
  3039 instantiation of terms from the current context.  This is applied to
  3040 specifications and theorems of the interpreted expression.
  3041 Interpretation in locales only permits parameter renaming through the
  3042 locale expression.  Interpretation is smart in that interpretations
  3043 that are active already do not occur in proof obligations, neither are
  3044 instantiated theorems stored in duplicate.  Use 'print_interps' to
  3045 inspect active interpretations of a particular locale.  For details,
  3046 see the Isar Reference manual.  Examples can be found in
  3047 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  3048 
  3049 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  3050 'interpret' instead.
  3051 
  3052 * New context element 'constrains' for adding type constraints to
  3053 parameters.
  3054 
  3055 * Context expressions: renaming of parameters with syntax
  3056 redeclaration.
  3057 
  3058 * Locale declaration: 'includes' disallowed.
  3059 
  3060 * Proper static binding of attribute syntax -- i.e. types / terms /
  3061 facts mentioned as arguments are always those of the locale definition
  3062 context, independently of the context of later invocations.  Moreover,
  3063 locale operations (renaming and type / term instantiation) are applied
  3064 to attribute arguments as expected.
  3065 
  3066 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  3067 actual attributes; rare situations may require Attrib.attribute to
  3068 embed those attributes into Attrib.src that lack concrete syntax.
  3069 Attribute implementations need to cooperate properly with the static
  3070 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  3071 Attrib.XXX_thm etc. already do the right thing without further
  3072 intervention.  Only unusual applications -- such as "where" or "of"
  3073 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  3074 on the context and the facts involved -- may have to assign parsed
  3075 values to argument tokens explicitly.
  3076 
  3077 * Changed parameter management in theorem generation for long goal
  3078 statements with 'includes'.  INCOMPATIBILITY: produces a different
  3079 theorem statement in rare situations.
  3080 
  3081 * Locale inspection command 'print_locale' omits notes elements.  Use
  3082 'print_locale!' to have them included in the output.
  3083 
  3084 
  3085 *** Provers ***
  3086 
  3087 * Provers/hypsubst.ML: improved version of the subst method, for
  3088 single-step rewriting: it now works in bound variable contexts. New is
  3089 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  3090 rewrite a different subterm than the original subst method, which is
  3091 still available as 'simplesubst'.
  3092 
  3093 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  3094 and quasi orders.
  3095 
  3096 * Provers/trancl.ML: new transitivity reasoner for transitive and
  3097 reflexive-transitive closure of relations.
  3098 
  3099 * Provers/blast.ML: new reference depth_limit to make blast's depth
  3100 limit (previously hard-coded with a value of 20) user-definable.
  3101 
  3102 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  3103 is peformed already.  Object-logics merely need to finish their
  3104 initial simpset configuration as before.  INCOMPATIBILITY.
  3105 
  3106 
  3107 *** HOL ***
  3108 
  3109 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3110 
  3111   syntax (epsilon)
  3112     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3113 
  3114 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3115 and x-symbol; use option '-m epsilon' to get it actually printed.
  3116 Moreover, the mathematically important symbolic identifier \<epsilon>
  3117 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3118 
  3119 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3120 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3121 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3122 support corresponding Isar calculations.
  3123 
  3124 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3125 instead of ":".
  3126 
  3127 * theory SetInterval: changed the syntax for open intervals:
  3128 
  3129   Old       New
  3130   {..n(}    {..<n}
  3131   {)n..}    {n<..}
  3132   {m..n(}   {m..<n}
  3133   {)m..n}   {m<..n}
  3134   {)m..n(}  {m<..<n}
  3135 
  3136 The old syntax is still supported but will disappear in the next
  3137 release.  For conversion use the following Emacs search and replace
  3138 patterns (these are not perfect but work quite well):
  3139 
  3140   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3141   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3142 
  3143 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3144 equalities in commutative rings; method 'algebra' provides a generic
  3145 interface.
  3146 
  3147 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3148 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3149 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3150 be a tuple pattern.
  3151 
  3152 Some new syntax forms are available:
  3153 
  3154   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3155   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3156   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3157   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3158 
  3159 The latter form "\<Sum>x < k. e" used to be based on a separate
  3160 function "Summation", which has been discontinued.
  3161 
  3162 * theory Finite_Set: in structured induction proofs, the insert case
  3163 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3164 (insert F x)'.
  3165 
  3166 * The 'refute' command has been extended to support a much larger
  3167 fragment of HOL, including axiomatic type classes, constdefs and
  3168 typedefs, inductive datatypes and recursion.
  3169 
  3170 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3171 Requires zChaff with proof generation to be installed.  See
  3172 HOL/ex/SAT_Examples.thy for examples.
  3173 
  3174 * Datatype induction via method 'induct' now preserves the name of the
  3175 induction variable. For example, when proving P(xs::'a list) by
  3176 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3177 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3178 in unstructured proof scripts.
  3179 
  3180 * Reworked implementation of records.  Improved scalability for
  3181 records with many fields, avoiding performance problems for type
  3182 inference. Records are no longer composed of nested field types, but
  3183 of nested extension types. Therefore the record type only grows linear
  3184 in the number of extensions and not in the number of fields.  The
  3185 top-level (users) view on records is preserved.  Potential
  3186 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3187 old record representation. The type generated for a record is called
  3188 <record_name>_ext_type.
  3189 
  3190 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3191 proofs triggered by a record definition or a simproc (if
  3192 quick_and_dirty is enabled).  Definitions of large records can take
  3193 quite long.
  3194 
  3195 New simproc record_upd_simproc for simplification of multiple record
  3196 updates enabled by default.  Moreover, trivial updates are also
  3197 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3198 occasionally, since simplification is more powerful by default.
  3199 
  3200 * typedef: proper support for polymorphic sets, which contain extra
  3201 type-variables in the term.
  3202 
  3203 * Simplifier: automatically reasons about transitivity chains
  3204 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3205 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3206 old proofs break occasionally as simplification may now solve more
  3207 goals than previously.
  3208 
  3209 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3210 present.  Works for all partial orders (class "order"), in particular
  3211 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3212 just like y <= x.
  3213 
  3214 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3215 bound variable or a constant then the let is unfolded.  Otherwise
  3216 first a is simplified to b, and then f b is simplified to g. If
  3217 possible we abstract b from g arriving at "let x = b in h x",
  3218 otherwise we unfold the let and arrive at g.  The simproc can be
  3219 enabled/disabled by the reference use_let_simproc.  Potential
  3220 INCOMPATIBILITY since simplification is more powerful by default.
  3221 
  3222 * Classical reasoning: the meson method now accepts theorems as arguments.
  3223 
  3224 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3225 jobs to provide advice on the provability of subgoals.
  3226 
  3227 * Theory OrderedGroup and Ring_and_Field: various additions and
  3228 improvements to faciliate calculations involving equalities and
  3229 inequalities.
  3230 
  3231 The following theorems have been eliminated or modified
  3232 (INCOMPATIBILITY):
  3233 
  3234   abs_eq             now named abs_of_nonneg
  3235   abs_of_ge_0        now named abs_of_nonneg
  3236   abs_minus_eq       now named abs_of_nonpos
  3237   imp_abs_id         now named abs_of_nonneg
  3238   imp_abs_neg_id     now named abs_of_nonpos
  3239   mult_pos           now named mult_pos_pos
  3240   mult_pos_le        now named mult_nonneg_nonneg
  3241   mult_pos_neg_le    now named mult_nonneg_nonpos
  3242   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3243   mult_neg           now named mult_neg_neg
  3244   mult_neg_le        now named mult_nonpos_nonpos
  3245 
  3246 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3247      
  3248      zero_le_square
  3249      not_square_less_zero 
  3250 
  3251   The following lemmas have been deleted from Real/RealPow:
  3252   
  3253      realpow_zero_zero
  3254      realpow_two
  3255      realpow_less
  3256      zero_le_power
  3257      realpow_two_le
  3258      abs_realpow_two
  3259      realpow_two_abs     
  3260 
  3261 * Theory Parity: added rules for simplifying exponents.
  3262 
  3263 * Theory List:
  3264 
  3265 The following theorems have been eliminated or modified
  3266 (INCOMPATIBILITY):
  3267 
  3268   list_all_Nil       now named list_all.simps(1)
  3269   list_all_Cons      now named list_all.simps(2)
  3270   list_all_conv      now named list_all_iff
  3271   set_mem_eq         now named mem_iff
  3272 
  3273 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3274 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3275 
  3276 
  3277 *** HOL-Complex ***
  3278 
  3279 * Theory RealDef: better support for embedding natural numbers and
  3280 integers in the reals.
  3281 
  3282 The following theorems have been eliminated or modified
  3283 (INCOMPATIBILITY):
  3284 
  3285   exp_ge_add_one_self  now requires no hypotheses
  3286   real_of_int_add      reversed direction of equality (use [symmetric])
  3287   real_of_int_minus    reversed direction of equality (use [symmetric])
  3288   real_of_int_diff     reversed direction of equality (use [symmetric])
  3289   real_of_int_mult     reversed direction of equality (use [symmetric])
  3290 
  3291 * Theory RComplete: expanded support for floor and ceiling functions.
  3292 
  3293 * Theory Ln is new, with properties of the natural logarithm
  3294 
  3295 * Hyperreal: There is a new type constructor "star" for making
  3296 nonstandard types.  The old type names are now type synonyms:
  3297 
  3298   hypreal = real star
  3299   hypnat = nat star
  3300   hcomplex = complex star
  3301 
  3302 * Hyperreal: Many groups of similarly-defined constants have been
  3303 replaced by polymorphic versions (INCOMPATIBILITY):
  3304 
  3305   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3306 
  3307   starset      <-- starsetNat, starsetC
  3308   *s*          <-- *sNat*, *sc*
  3309   starset_n    <-- starsetNat_n, starsetC_n
  3310   *sn*         <-- *sNatn*, *scn*
  3311   InternalSets <-- InternalNatSets, InternalCSets
  3312 
  3313   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3314   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3315   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3316   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3317   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3318 
  3319 * Hyperreal: Many type-specific theorems have been removed in favor of
  3320 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3321 
  3322   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3323   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3324   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3325   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3326   right_minus <-- hypreal_add_minus
  3327   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3328   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3329   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3330   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3331   mult_1_right <-- hcomplex_mult_one_right
  3332   mult_zero_left <-- hcomplex_mult_zero_left
  3333   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3334   right_distrib <-- hypnat_add_mult_distrib2
  3335   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3336   right_inverse <-- hypreal_mult_inverse
  3337   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3338   order_refl <-- {hypreal,hypnat}_le_refl
  3339   order_trans <-- {hypreal,hypnat}_le_trans
  3340   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3341   order_less_le <-- {hypreal,hypnat}_less_le
  3342   linorder_linear <-- {hypreal,hypnat}_le_linear
  3343   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3344   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3345   add_nonneg_nonneg <-- hypreal_le_add_order
  3346 
  3347 * Hyperreal: Separate theorems having to do with type-specific
  3348 versions of constants have been merged into theorems that apply to the
  3349 new polymorphic constants (INCOMPATIBILITY):
  3350 
  3351   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3352   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3353   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3354   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3355   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3356   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3357   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3358   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3359   STAR_diff <-- {STAR,STARC}_diff
  3360   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3361     STARC_hcomplex_of_complex}_image_subset
  3362   starset_n_Un <-- starset{Nat,C}_n_Un
  3363   starset_n_Int <-- starset{Nat,C}_n_Int
  3364   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3365   starset_n_diff <-- starset{Nat,C}_n_diff
  3366   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3367   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3368   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3369   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3370   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3371   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3372   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3373   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3374   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3375   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3376   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3377   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3378   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3379   starfun_diff <-- starfun{C,RC,CR}_diff
  3380   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3381   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3382   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3383   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3384   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3385   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3386   starfun_Id <-- starfunC_Id
  3387   starfun_approx <-- starfun{Nat,CR}_approx
  3388   starfun_capprox <-- starfun{C,RC}_capprox
  3389   starfun_abs <-- starfunNat_rabs
  3390   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3391   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3392   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3393   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3394   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3395   starfun_add_approx <-- starfunCR_add_approx
  3396   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3397   starfun_divide <-- starfun{C,CR,RC}_divide
  3398   starfun_n <-- starfun{Nat,C}_n
  3399   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3400   starfun_n_add <-- starfun{Nat,C}_n_add
  3401   starfun_n_add_minus <-- starfunNat_n_add_minus
  3402   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3403   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3404   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3405 
  3406   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3407   star_n_minus <-- {hypreal,hcomplex}_minus
  3408   star_n_diff <-- {hypreal,hcomplex}_diff
  3409   star_n_mult <-- {hypreal,hcomplex}_mult
  3410   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3411   star_n_le <-- {hypreal,hypnat}_le
  3412   star_n_less <-- {hypreal,hypnat}_less
  3413   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3414   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3415   star_n_abs <-- hypreal_hrabs
  3416   star_n_divide <-- hcomplex_divide
  3417 
  3418   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3419   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3420   star_of_diff <-- hypreal_of_real_diff
  3421   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3422   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3423   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3424   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3425   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3426   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3427   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3428   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3429   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3430   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3431   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3432   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3433   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3434   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3435   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3436   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3437   star_of_power <-- hypreal_of_real_power
  3438   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3439 
  3440 * Hyperreal: new method "transfer" that implements the transfer
  3441 principle of nonstandard analysis. With a subgoal that mentions
  3442 nonstandard types like "'a star", the command "apply transfer"
  3443 replaces it with an equivalent one that mentions only standard types.
  3444 To be successful, all free variables must have standard types; non-
  3445 standard variables must have explicit universal quantifiers.
  3446 
  3447 * Hyperreal: A theory of Taylor series.
  3448 
  3449 
  3450 *** HOLCF ***
  3451 
  3452 * Discontinued special version of 'constdefs' (which used to support
  3453 continuous functions) in favor of the general Pure one with full
  3454 type-inference.
  3455 
  3456 * New simplification procedure for solving continuity conditions; it
  3457 is much faster on terms with many nested lambda abstractions (cubic
  3458 instead of exponential time).
  3459 
  3460 * New syntax for domain package: selector names are now optional.
  3461 Parentheses should be omitted unless argument is lazy, for example:
  3462 
  3463   domain 'a stream = cons "'a" (lazy "'a stream")
  3464 
  3465 * New command 'fixrec' for defining recursive functions with pattern
  3466 matching; defining multiple functions with mutual recursion is also
  3467 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3468 sinr, or any data constructor defined by the domain package. The given
  3469 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3470 syntax and examples.
  3471 
  3472 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3473 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3474 but the proof obligation additionally includes an admissibility
  3475 requirement. The packages generate instances of class cpo or pcpo,
  3476 with continuity and strictness theorems for Rep and Abs.
  3477 
  3478 * HOLCF: Many theorems have been renamed according to a more standard naming
  3479 scheme (INCOMPATIBILITY):
  3480 
  3481   foo_inject:  "foo$x = foo$y ==> x = y"
  3482   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3483   foo_less:    "(foo$x << foo$y) = (x << y)"
  3484   foo_strict:  "foo$UU = UU"
  3485   foo_defined: "... ==> foo$x ~= UU"
  3486   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3487 
  3488 
  3489 *** ZF ***
  3490 
  3491 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3492 including the First Isomorphism Theorem (on quotienting by the kernel
  3493 of a homomorphism).
  3494 
  3495 * ZF/Simplifier: install second copy of type solver that actually
  3496 makes use of TC rules declared to Isar proof contexts (or locales);
  3497 the old version is still required for ML proof scripts.
  3498 
  3499 
  3500 *** Cube ***
  3501 
  3502 * Converted to Isar theory format; use locales instead of axiomatic
  3503 theories.
  3504 
  3505 
  3506 *** ML ***
  3507 
  3508 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3509 for ||>, ||>>, |>>,
  3510 
  3511 * Pure/library.ML no longer defines its own option datatype, but uses
  3512 that of the SML basis, which has constructors NONE and SOME instead of
  3513 None and Some, as well as exception Option.Option instead of OPTION.
  3514 The functions the, if_none, is_some, is_none have been adapted
  3515 accordingly, while Option.map replaces apsome.
  3516 
  3517 * Pure/library.ML: the exception LIST has been given up in favour of
  3518 the standard exceptions Empty and Subscript, as well as
  3519 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3520 superceded by the standard hd and tl functions etc.
  3521 
  3522 A number of basic list functions are no longer exported to the ML
  3523 toplevel, as they are variants of predefined functions.  The following
  3524 suggests how one can translate existing code:
  3525 
  3526     rev_append xs ys = List.revAppend (xs, ys)
  3527     nth_elem (i, xs) = List.nth (xs, i)
  3528     last_elem xs = List.last xs
  3529     flat xss = List.concat xss
  3530     seq fs = List.app fs
  3531     partition P xs = List.partition P xs
  3532     mapfilter f xs = List.mapPartial f xs
  3533 
  3534 * Pure/library.ML: several combinators for linear functional
  3535 transformations, notably reverse application and composition:
  3536 
  3537   x |> f                f #> g
  3538   (x, y) |-> f          f #-> g
  3539 
  3540 * Pure/library.ML: introduced/changed precedence of infix operators:
  3541 
  3542   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3543   infix 2 ?;
  3544   infix 3 o oo ooo oooo;
  3545   infix 4 ~~ upto downto;
  3546 
  3547 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3548 infix operators.
  3549 
  3550 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3551 fold_map support linear functional transformations and nesting.  For
  3552 example:
  3553 
  3554   fold f [x1, ..., xN] y =
  3555     y |> f x1 |> ... |> f xN
  3556 
  3557   (fold o fold) f [xs1, ..., xsN] y =
  3558     y |> fold f xs1 |> ... |> fold f xsN
  3559 
  3560   fold f [x1, ..., xN] =
  3561     f x1 #> ... #> f xN
  3562 
  3563   (fold o fold) f [xs1, ..., xsN] =
  3564     fold f xs1 #> ... #> fold f xsN
  3565 
  3566 * Pure/library.ML: the following selectors on type 'a option are
  3567 available:
  3568 
  3569   the:               'a option -> 'a  (*partial*)
  3570   these:             'a option -> 'a  where 'a = 'b list
  3571   the_default: 'a -> 'a option -> 'a
  3572   the_list:          'a option -> 'a list
  3573 
  3574 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3575 basic operations for association lists, following natural argument
  3576 order; moreover the explicit equality predicate passed here avoids
  3577 potentially expensive polymorphic runtime equality checks.
  3578 The old functions may be expressed as follows:
  3579 
  3580   assoc = uncurry (AList.lookup (op =))
  3581   assocs = these oo AList.lookup (op =)
  3582   overwrite = uncurry (AList.update (op =)) o swap
  3583 
  3584 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3585 
  3586   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3587   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3588 
  3589 replacing make_keylist and keyfilter (occassionally used)
  3590 Naive rewrites:
  3591 
  3592   make_keylist = AList.make
  3593   keyfilter = AList.find (op =)
  3594 
  3595 * eq_fst and eq_snd now take explicit equality parameter, thus
  3596   avoiding eqtypes. Naive rewrites:
  3597 
  3598     eq_fst = eq_fst (op =)
  3599     eq_snd = eq_snd (op =)
  3600 
  3601 * Removed deprecated apl and apr (rarely used).
  3602   Naive rewrites:
  3603 
  3604     apl (n, op) =>>= curry op n
  3605     apr (op, m) =>>= fn n => op (n, m)
  3606 
  3607 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3608 provides a reasonably efficient light-weight implementation of sets as
  3609 lists.
  3610 
  3611 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3612 few new operations; existing lookup and update are now curried to
  3613 follow natural argument order (for use with fold etc.);
  3614 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3615 
  3616 * Pure/General: output via the Isabelle channels of
  3617 writeln/warning/error etc. is now passed through Output.output, with a
  3618 hook for arbitrary transformations depending on the print_mode
  3619 (cf. Output.add_mode -- the first active mode that provides a output
  3620 function wins).  Already formatted output may be embedded into further
  3621 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3622 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3623 accommodate easy composition of diagnostic messages etc.  Programmers
  3624 rarely need to care about Output.output or Output.raw at all, with
  3625 some notable exceptions: Output.output is required when bypassing the
  3626 standard channels (writeln etc.), or in token translations to produce
  3627 properly formatted results; Output.raw is required when capturing
  3628 already output material that will eventually be presented to the user
  3629 a second time.  For the default print mode, both Output.output and
  3630 Output.raw have no effect.
  3631 
  3632 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3633 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3634 cumulative results are displayed at the end of a batch session.
  3635 
  3636 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3637 replaced by File.platform_path and File.shell_path (with appropriate
  3638 hooks).  This provides a clean interface for unusual systems where the
  3639 internal and external process view of file names are different.
  3640 
  3641 * Pure: more efficient orders for basic syntactic entities: added
  3642 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3643 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3644 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3645 orders now -- potential INCOMPATIBILITY for code that depends on a
  3646 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3647 Library.sort_strings on result).
  3648 
  3649 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3650 fold_types traverse types/terms from left to right, observing natural
  3651 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3652 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3653 
  3654 * Pure: name spaces have been refined, with significant changes of the
  3655 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3656 to extern(_table).  The plain name entry path is superceded by a
  3657 general 'naming' context, which also includes the 'policy' to produce
  3658 a fully qualified name and external accesses of a fully qualified
  3659 name; NameSpace.extend is superceded by context dependent
  3660 Sign.declare_name.  Several theory and proof context operations modify
  3661 the naming context.  Especially note Theory.restore_naming and
  3662 ProofContext.restore_naming to get back to a sane state; note that
  3663 Theory.add_path is no longer sufficient to recover from
  3664 Theory.absolute_path in particular.
  3665 
  3666 * Pure: new flags short_names (default false) and unique_names
  3667 (default true) for controlling output of qualified names.  If
  3668 short_names is set, names are printed unqualified.  If unique_names is
  3669 reset, the name prefix is reduced to the minimum required to achieve
  3670 the original result when interning again, even if there is an overlap
  3671 with earlier declarations.
  3672 
  3673 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3674 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3675 (useful for printing error messages).  INCOMPATIBILITY.
  3676 
  3677 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3678 Theory.theory are now identified, referring to the universal
  3679 Context.theory (see Pure/context.ML).  Actual signature and theory
  3680 content is managed as theory data.  The old code and interfaces were
  3681 spread over many files and structures; the new arrangement introduces
  3682 considerable INCOMPATIBILITY to gain more clarity:
  3683 
  3684   Context -- theory management operations (name, identity, inclusion,
  3685     parents, ancestors, merge, etc.), plus generic theory data;
  3686 
  3687   Sign -- logical signature and syntax operations (declaring consts,
  3688     types, etc.), plus certify/read for common entities;
  3689 
  3690   Theory -- logical theory operations (stating axioms, definitions,
  3691     oracles), plus a copy of logical signature operations (consts,
  3692     types, etc.); also a few basic management operations (Theory.copy,
  3693     Theory.merge, etc.)
  3694 
  3695 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3696 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3697 for convenience -- they merely return the theory.
  3698 
  3699 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3700 
  3701 * Pure: the Isar proof context type is already defined early in Pure
  3702 as Context.proof (note that ProofContext.context and Proof.context are
  3703 aliases, where the latter is the preferred name).  This enables other
  3704 Isabelle components to refer to that type even before Isar is present.
  3705 
  3706 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3707 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3708 any of these kinds.  For example, Sign.intern typeK is now
  3709 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3710 Theory.hide_types.  Also note that former
  3711 Theory.hide_classes/types/consts are now
  3712 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3713 internalize their arguments!  INCOMPATIBILITY.
  3714 
  3715 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3716 datatype thmref (with constructors Name and NameSelection) instead of
  3717 plain string -- INCOMPATIBILITY;
  3718 
  3719 * Pure: cases produced by proof methods specify options, where NONE
  3720 means to remove case bindings -- INCOMPATIBILITY in
  3721 (RAW_)METHOD_CASES.
  3722 
  3723 * Pure: the following operations retrieve axioms or theorems from a
  3724 theory node or theory hierarchy, respectively:
  3725 
  3726   Theory.axioms_of: theory -> (string * term) list
  3727   Theory.all_axioms_of: theory -> (string * term) list
  3728   PureThy.thms_of: theory -> (string * thm) list
  3729   PureThy.all_thms_of: theory -> (string * thm) list
  3730 
  3731 * Pure: print_tac now outputs the goal through the trace channel.
  3732 
  3733 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3734 Reference Toplevel.debug (default false) controls detailed printing
  3735 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3736 controls execution profiling -- set to 1 for time and 2 for space
  3737 (both increase the runtime).
  3738 
  3739 * Isar session: The initial use of ROOT.ML is now always timed,
  3740 i.e. the log will show the actual process times, in contrast to the
  3741 elapsed wall-clock time that the outer shell wrapper produces.
  3742 
  3743 * Simplifier: improved handling of bound variables (nameless
  3744 representation, avoid allocating new strings).  Simprocs that invoke
  3745 the Simplifier recursively should use Simplifier.inherit_bounds to
  3746 avoid local name clashes.  Failure to do so produces warnings
  3747 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3748 for further details.
  3749 
  3750 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3751 bindings for all theorems stored within a given theory; this may help
  3752 in porting non-Isar theories to Isar ones, while keeping ML proof
  3753 scripts for the time being.
  3754 
  3755 * ML operator HTML.with_charset specifies the charset begin used for
  3756 generated HTML files.  For example:
  3757 
  3758   HTML.with_charset "utf-8" use_thy "Hebrew";
  3759   HTML.with_charset "utf-8" use_thy "Chinese";
  3760 
  3761 
  3762 *** System ***
  3763 
  3764 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3765 isabelle, isatool etc.).
  3766 
  3767 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3768 isatool doc, isatool mkdir, display_drafts etc.).
  3769 
  3770 * isatool usedir: option -f allows specification of the ML file to be
  3771 used by Isabelle; default is ROOT.ML.
  3772 
  3773 * New isatool version outputs the version identifier of the Isabelle
  3774 distribution being used.
  3775 
  3776 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3777 (containing Boolean satisfiability problems) into Isabelle/HOL
  3778 theories.
  3779 
  3780 
  3781 
  3782 New in Isabelle2004 (April 2004)
  3783 --------------------------------
  3784 
  3785 *** General ***
  3786 
  3787 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3788   Replaces linorder.ML.
  3789 
  3790 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3791   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3792   (\<a>...\<z>), are now considered normal letters, and can therefore
  3793   be used anywhere where an ASCII letter (a...zA...Z) has until
  3794   now. COMPATIBILITY: This obviously changes the parsing of some
  3795   terms, especially where a symbol has been used as a binder, say
  3796   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3797   as an identifier.  Fix it by inserting a space around former
  3798   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3799   existing theory and ML files.
  3800 
  3801 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3802 
  3803 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3804   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3805   a normal (but invisible) letter. For multiple letter subscripts repeat
  3806   \<^isub> like this: x\<^isub>1\<^isub>2.
  3807 
  3808 * Pure: There are now sub-/superscripts that can span more than one
  3809   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3810   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3811   superscript. The new control characters are not identifier parts.
  3812 
  3813 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3814   content of "..." to the latex file instead of \isacntrl... . The "..."
  3815   may consist of any printable characters excluding the end bracket >.
  3816 
  3817 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3818   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3819   declare constants "final", which prevents their being given a definition
  3820   later.  It is useful for constants whose behaviour is fixed axiomatically
  3821   rather than definitionally, such as the meta-logic connectives.
  3822 
  3823 * Pure: 'instance' now handles general arities with general sorts
  3824   (i.e. intersections of classes),
  3825 
  3826 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3827   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3828   It can be changed to alter the colors/layout of generated pages.
  3829 
  3830 
  3831 *** Isar ***
  3832 
  3833 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3834   cut_tac, subgoal_tac and thin_tac:
  3835   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3836     locales are no longer forced to write Isar proof scripts.
  3837     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3838     emulations.
  3839   - INCOMPATIBILITY: names of variables to be instantiated may no
  3840     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3841     This is consistent with the instantiation attribute "where".
  3842 
  3843 * Attributes "where" and "of":
  3844   - Now take type variables of instantiated theorem into account when reading
  3845     the instantiation string.  This fixes a bug that caused instantiated
  3846     theorems to have too special types in some circumstances.
  3847   - "where" permits explicit instantiations of type variables.
  3848 
  3849 * Calculation commands "moreover" and "also" no longer interfere with
  3850   current facts ("this"), admitting arbitrary combinations with "then"
  3851   and derived forms.
  3852 
  3853 * Locales:
  3854   - Goal statements involving the context element "includes" no longer
  3855     generate theorems with internal delta predicates (those ending on
  3856     "_axioms") in the premise.
  3857     Resolve particular premise with <locale>.intro to obtain old form.
  3858   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3859     specification and "includes" elements in goal statement.
  3860   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3861     [intro?] and [elim?] (respectively) by default.
  3862   - Experimental command for instantiation of locales in proof contexts:
  3863         instantiate <label>[<attrs>]: <loc>
  3864     Instantiates locale <loc> and adds all its theorems to the current context
  3865     taking into account their attributes.  Label and attrs are optional
  3866     modifiers, like in theorem declarations.  If present, names of
  3867     instantiated theorems are qualified with <label>, and the attributes
  3868     <attrs> are applied after any attributes these theorems might have already.
  3869       If the locale has assumptions, a chained fact of the form
  3870     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3871     are derived.  The command does not support old-style locales declared
  3872     with "locale (open)".
  3873       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3874 
  3875 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3876   (Isar) contexts.
  3877 
  3878 
  3879 *** HOL ***
  3880 
  3881 * Proof import: new image HOL4 contains the imported library from
  3882   the HOL4 system with about 2500 theorems. It is imported by
  3883   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3884   can be used like any other Isabelle image.  See
  3885   HOL/Import/HOL/README for more information.
  3886 
  3887 * Simplifier:
  3888   - Much improved handling of linear and partial orders.
  3889     Reasoners for linear and partial orders are set up for type classes
  3890     "linorder" and "order" respectively, and are added to the default simpset
  3891     as solvers.  This means that the simplifier can build transitivity chains
  3892     to solve goals from the assumptions.
  3893   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3894     of blast or auto after simplification become unnecessary because the goal
  3895     is solved by simplification already.
  3896 
  3897 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3898     all proved in axiomatic type classes for semirings, rings and fields.
  3899 
  3900 * Numerics:
  3901   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3902     now formalized using the Ring_and_Field theory mentioned above.
  3903   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3904     than before, because now they are set up once in a generic manner.
  3905   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3906     Look for the general versions in Ring_and_Field (and Power if they concern
  3907     exponentiation).
  3908 
  3909 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3910 
  3911 * Records:
  3912   - Record types are now by default printed with their type abbreviation
  3913     instead of the list of all field types. This can be configured via
  3914     the reference "print_record_type_abbr".
  3915   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3916     (not enabled by default).
  3917   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3918     EX x. x = sel r to True (not enabled by default).
  3919   - Tactic "record_split_simp_tac" to split and simplify records added.
  3920 
  3921 * 'specification' command added, allowing for definition by
  3922   specification.  There is also an 'ax_specification' command that
  3923   introduces the new constants axiomatically.
  3924 
  3925 * arith(_tac) is now able to generate counterexamples for reals as well.
  3926 
  3927 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3928 
  3929 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3930   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3931 
  3932 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3933   matrix theory to linear programming.
  3934 
  3935 * Unions and Intersections:
  3936   The latex output syntax of UN and INT has been changed
  3937   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3938   i.e. the index formulae has become a subscript.
  3939   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3940 
  3941 * Unions and Intersections over Intervals:
  3942   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3943   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3944   like in normal math, and corresponding versions for < and for intersection.
  3945 
  3946 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3947   lexicographic dictonary ordering has been added as "lexord".
  3948 
  3949 * ML: the legacy theory structures Int and List have been removed. They had
  3950   conflicted with ML Basis Library structures having the same names.
  3951 
  3952 * 'refute' command added to search for (finite) countermodels.  Only works
  3953   for a fragment of HOL.  The installation of an external SAT solver is
  3954   highly recommended.  See "HOL/Refute.thy" for details.
  3955 
  3956 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3957   formulae under an assignment of free variables to random values.
  3958   In contrast to 'refute', it can deal with inductive datatypes,
  3959   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3960   for examples.
  3961 
  3962 
  3963 *** HOLCF ***
  3964 
  3965 * Streams now come with concatenation and are part of the HOLCF image
  3966 
  3967 
  3968 
  3969 New in Isabelle2003 (May 2003)
  3970 ------------------------------
  3971 
  3972 *** General ***
  3973 
  3974 * Provers/simplifier:
  3975 
  3976   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3977     Assumptions are now subject to complete mutual simplification,
  3978     not just from left to right. The simplifier now preserves
  3979     the order of assumptions.
  3980 
  3981     Potential INCOMPATIBILITY:
  3982 
  3983     -- simp sometimes diverges where the old version did
  3984        not, e.g. invoking simp on the goal
  3985 
  3986         [| P (f x); y = x; f x = f y |] ==> Q
  3987 
  3988        now gives rise to the infinite reduction sequence
  3989 
  3990         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3991 
  3992        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3993        kind of problem.
  3994 
  3995     -- Tactics combining classical reasoner and simplification (such as auto)
  3996        are also affected by this change, because many of them rely on
  3997        simp. They may sometimes diverge as well or yield a different numbers
  3998        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3999        in case of problems. Sometimes subsequent calls to the classical
  4000        reasoner will fail because a preceeding call to the simplifier too
  4001        eagerly simplified the goal, e.g. deleted redundant premises.
  4002 
  4003   - The simplifier trace now shows the names of the applied rewrite rules
  4004 
  4005   - You can limit the number of recursive invocations of the simplifier
  4006     during conditional rewriting (where the simplifie tries to solve the
  4007     conditions before applying the rewrite rule):
  4008     ML "simp_depth_limit := n"
  4009     where n is an integer. Thus you can force termination where previously
  4010     the simplifier would diverge.
  4011 
  4012   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  4013 
  4014   - No longer aborts on failed congruence proof.  Instead, the
  4015     congruence is ignored.
  4016 
  4017 * Pure: New generic framework for extracting programs from constructive
  4018   proofs. See HOL/Extraction.thy for an example instantiation, as well
  4019   as HOL/Extraction for some case studies.
  4020 
  4021 * Pure: The main goal of the proof state is no longer shown by default, only
  4022 the subgoals. This behaviour is controlled by a new flag.
  4023    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  4024 (ML: Proof.show_main_goal).
  4025 
  4026 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  4027 rules whose conclusion matches subgoal 1:
  4028       PG menu: Isabelle/Isar -> Show me -> matching rules
  4029 The rules are ordered by how closely they match the subgoal.
  4030 In particular, rules that solve a subgoal outright are displayed first
  4031 (or rather last, the way they are printed).
  4032 (ML: ProofGeneral.print_intros())
  4033 
  4034 * Pure: New flag trace_unify_fail causes unification to print
  4035 diagnostic information (PG: in trace buffer) when it fails. This is
  4036 useful for figuring out why single step proofs like rule, erule or
  4037 assumption failed.
  4038 
  4039 * Pure: Locale specifications now produce predicate definitions
  4040 according to the body of text (covering assumptions modulo local
  4041 definitions); predicate "loc_axioms" covers newly introduced text,
  4042 while "loc" is cumulative wrt. all included locale expressions; the
  4043 latter view is presented only on export into the global theory
  4044 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  4045 on the old view without predicates;
  4046 
  4047 * Pure: predefined locales "var" and "struct" are useful for sharing
  4048 parameters (as in CASL, for example); just specify something like
  4049 ``var x + var y + struct M'' as import;
  4050 
  4051 * Pure: improved thms_containing: proper indexing of facts instead of
  4052 raw theorems; check validity of results wrt. current name space;
  4053 include local facts of proof configuration (also covers active
  4054 locales), cover fixed variables in index; may use "_" in term
  4055 specification; an optional limit for the number of printed facts may
  4056 be given (the default is 40);
  4057 
  4058 * Pure: disallow duplicate fact bindings within new-style theory files
  4059 (batch-mode only);
  4060 
  4061 * Provers: improved induct method: assumptions introduced by case
  4062 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  4063 the goal statement); "foo" still refers to all facts collectively;
  4064 
  4065 * Provers: the function blast.overloaded has been removed: all constants
  4066 are regarded as potentially overloaded, which improves robustness in exchange
  4067 for slight decrease in efficiency;
  4068 
  4069 * Provers/linorder: New generic prover for transitivity reasoning over
  4070 linear orders.  Note: this prover is not efficient!
  4071 
  4072 * Isar: preview of problems to finish 'show' now produce an error
  4073 rather than just a warning (in interactive mode);
  4074 
  4075 
  4076 *** HOL ***
  4077 
  4078 * arith(_tac)
  4079 
  4080  - Produces a counter example if it cannot prove a goal.
  4081    Note that the counter example may be spurious if the goal is not a formula
  4082    of quantifier-free linear arithmetic.
  4083    In ProofGeneral the counter example appears in the trace buffer.
  4084 
  4085  - Knows about div k and mod k where k is a numeral of type nat or int.
  4086 
  4087  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  4088    linear arithmetic fails. This takes account of quantifiers and divisibility.
  4089    Presburger arithmetic can also be called explicitly via presburger(_tac).
  4090 
  4091 * simp's arithmetic capabilities have been enhanced a bit: it now
  4092 takes ~= in premises into account (by performing a case split);
  4093 
  4094 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  4095 are distributed over a sum of terms;
  4096 
  4097 * New tactic "trans_tac" and method "trans" instantiate
  4098 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  4099 "<=", "<" and "=").
  4100 
  4101 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  4102 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  4103 
  4104 * 'typedef' command has new option "open" to suppress the set
  4105 definition;
  4106 
  4107 * functions Min and Max on finite sets have been introduced (theory
  4108 Finite_Set);
  4109 
  4110 * attribute [symmetric] now works for relations as well; it turns
  4111 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4112 
  4113 * induct over a !!-quantified statement (say !!x1..xn):
  4114   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4115 
  4116 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4117 %x. None. Warning: empty_def now refers to the previously hidden definition
  4118 of the empty set.
  4119 
  4120 * Algebra: formalization of classical algebra.  Intended as base for
  4121 any algebraic development in Isabelle.  Currently covers group theory
  4122 (up to Sylow's theorem) and ring theory (Universal Property of
  4123 Univariate Polynomials).  Contributions welcome;
  4124 
  4125 * GroupTheory: deleted, since its material has been moved to Algebra;
  4126 
  4127 * Complex: new directory of the complex numbers with numeric constants,
  4128 nonstandard complex numbers, and some complex analysis, standard and
  4129 nonstandard (Jacques Fleuriot);
  4130 
  4131 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4132 
  4133 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4134 Fleuriot);
  4135 
  4136 * Real/HahnBanach: updated and adapted to locales;
  4137 
  4138 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4139 Gray and Kramer);
  4140 
  4141 * UNITY: added the Meier-Sanders theory of progress sets;
  4142 
  4143 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4144 as abstract algorithms, instantiated to the JVM;
  4145 
  4146 * Bali: Java source language formalization. Type system, operational
  4147 semantics, axiomatic semantics. Supported language features:
  4148 classes, interfaces, objects,virtual methods, static methods,
  4149 static/instance fields, arrays, access modifiers, definite
  4150 assignment, exceptions.
  4151 
  4152 
  4153 *** ZF ***
  4154 
  4155 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4156 universe, etc.);
  4157 
  4158 * Main ZF: virtually all theories converted to new-style format;
  4159 
  4160 
  4161 *** ML ***
  4162 
  4163 * Pure: Tactic.prove provides sane interface for internal proofs;
  4164 omits the infamous "standard" operation, so this is more appropriate
  4165 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4166 
  4167 * Pure: improved error reporting of simprocs;
  4168 
  4169 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4170 up simprocs;
  4171 
  4172 
  4173 *** Document preparation ***
  4174 
  4175 * uses \par instead of \\ for line breaks in theory text. This may
  4176 shift some page breaks in large documents. To get the old behaviour
  4177 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4178 
  4179 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4180 other packages
  4181 
  4182 * \<euro> now needs package babel/greek instead of marvosym (which
  4183 broke \Rightarrow)
  4184 
  4185 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4186 textcomp package)
  4187 
  4188 
  4189 
  4190 New in Isabelle2002 (March 2002)
  4191 --------------------------------
  4192 
  4193 *** Document preparation ***
  4194 
  4195 * greatly simplified document preparation setup, including more
  4196 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4197 instructive isatool mkdir; users should basically be able to get
  4198 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4199 users may run a separate document processing stage manually like this:
  4200 "isatool usedir -D output HOL Test && isatool document Test/output";
  4201 
  4202 * theory dependency graph may now be incorporated into documents;
  4203 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4204 with \includegraphics of LaTeX;
  4205 
  4206 * proper spacing of consecutive markup elements, especially text
  4207 blocks after section headings;
  4208 
  4209 * support bold style (for single symbols only), input syntax is like
  4210 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4211 
  4212 * \<bullet> is now output as bold \cdot by default, which looks much
  4213 better in printed text;
  4214 
  4215 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4216 note that these symbols are currently unavailable in Proof General /
  4217 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4218 
  4219 * isatool latex no longer depends on changed TEXINPUTS, instead
  4220 isatool document copies the Isabelle style files to the target
  4221 location;
  4222 
  4223 
  4224 *** Isar ***
  4225 
  4226 * Pure/Provers: improved proof by cases and induction;
  4227   - 'case' command admits impromptu naming of parameters (such as
  4228     "case (Suc n)");
  4229   - 'induct' method divinates rule instantiation from the inductive
  4230     claim; no longer requires excessive ?P bindings for proper
  4231     instantiation of cases;
  4232   - 'induct' method properly enumerates all possibilities of set/type
  4233     rules; as a consequence facts may be also passed through *type*
  4234     rules without further ado;
  4235   - 'induct' method now derives symbolic cases from the *rulified*
  4236     rule (before it used to rulify cases stemming from the internal
  4237     atomized version); this means that the context of a non-atomic
  4238     statement becomes is included in the hypothesis, avoiding the
  4239     slightly cumbersome show "PROP ?case" form;
  4240   - 'induct' may now use elim-style induction rules without chaining
  4241     facts, using ``missing'' premises from the goal state; this allows
  4242     rules stemming from inductive sets to be applied in unstructured
  4243     scripts, while still benefitting from proper handling of non-atomic
  4244     statements; NB: major inductive premises need to be put first, all
  4245     the rest of the goal is passed through the induction;
  4246   - 'induct' proper support for mutual induction involving non-atomic
  4247     rule statements (uses the new concept of simultaneous goals, see
  4248     below);
  4249   - append all possible rule selections, but only use the first
  4250     success (no backtracking);
  4251   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4252   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4253   - added 'print_induct_rules' (covered by help item in recent Proof
  4254     General versions);
  4255   - moved induct/cases attributes to Pure, methods to Provers;
  4256   - generic method setup instantiated for FOL and HOL;
  4257 
  4258 * Pure: support multiple simultaneous goal statements, for example
  4259 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4260 meta-level mechanism, this acts as if several individual goals had
  4261 been stated separately; in particular common proof methods need to be
  4262 repeated in order to cover all claims; note that a single elimination
  4263 step is *not* sufficient to establish the two conjunctions, so this
  4264 fails:
  4265 
  4266   assume "A & B" then have A and B ..   (*".." fails*)
  4267 
  4268 better use "obtain" in situations as above; alternative refer to
  4269 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4270 
  4271 * Pure: proper integration with ``locales''; unlike the original
  4272 version by Florian Kammller, Isar locales package high-level proof
  4273 contexts rather than raw logical ones (e.g. we admit to include
  4274 attributes everywhere); operations on locales include merge and
  4275 rename; support for implicit arguments (``structures''); simultaneous
  4276 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4277 some examples;
  4278 
  4279 * Pure: the following commands have been ``localized'', supporting a
  4280 target locale specification "(in name)": 'lemma', 'theorem',
  4281 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4282 stored both within the locale and at the theory level (exported and
  4283 qualified by the locale name);
  4284 
  4285 * Pure: theory goals may now be specified in ``long'' form, with
  4286 ad-hoc contexts consisting of arbitrary locale elements. for example
  4287 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4288 definitions may be given, too); the result is a meta-level rule with
  4289 the context elements being discharged in the obvious way;
  4290 
  4291 * Pure: new proof command 'using' allows to augment currently used
  4292 facts after a goal statement ('using' is syntactically analogous to
  4293 'apply', but acts on the goal's facts only); this allows chained facts
  4294 to be separated into parts given before and after a claim, as in
  4295 ``from a and b have C using d and e <proof>'';
  4296 
  4297 * Pure: renamed "antecedent" case to "rule_context";
  4298 
  4299 * Pure: new 'judgment' command records explicit information about the
  4300 object-logic embedding (used by several tools internally); no longer
  4301 use hard-wired "Trueprop";
  4302 
  4303 * Pure: added 'corollary' command;
  4304 
  4305 * Pure: fixed 'token_translation' command;
  4306 
  4307 * Pure: removed obsolete 'exported' attribute;
  4308 
  4309 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4310 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4311 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4312 
  4313 * Pure: method 'atomize' presents local goal premises as object-level
  4314 statements (atomic meta-level propositions); setup controlled via
  4315 rewrite rules declarations of 'atomize' attribute; example
  4316 application: 'induct' method with proper rule statements in improper
  4317 proof *scripts*;
  4318 
  4319 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4320 now consider the syntactic context of assumptions, giving a better
  4321 chance to get type-inference of the arguments right (this is
  4322 especially important for locales);
  4323 
  4324 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4325 mode;
  4326 
  4327 * Pure/obtain: the formal conclusion "thesis", being marked as
  4328 ``internal'', may no longer be reference directly in the text;
  4329 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4330 situations;
  4331 
  4332 * Pure: generic 'sym' attribute which declares a rule both as pure
  4333 'elim?' and for the 'symmetric' operation;
  4334 
  4335 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4336 text; the fixed correlation with particular command syntax has been
  4337 discontinued;
  4338 
  4339 * Pure: new method 'rules' is particularly well-suited for proof
  4340 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4341 but often produces more compact proof terms with less detours;
  4342 
  4343 * Pure/Provers/classical: simplified integration with pure rule
  4344 attributes and methods; the classical "intro?/elim?/dest?"
  4345 declarations coincide with the pure ones; the "rule" method no longer
  4346 includes classically swapped intros; "intro" and "elim" methods no
  4347 longer pick rules from the context; also got rid of ML declarations
  4348 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4349 INCOMPATIBILITY;
  4350 
  4351 * Provers/classical: attribute 'swapped' produces classical inversions
  4352 of introduction rules;
  4353 
  4354 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4355 rules instead of full simplifier context; 'iff' attribute handles
  4356 conditional rules;
  4357 
  4358 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4359 
  4360 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4361 "(permissive)" option to recover old behavior;
  4362 
  4363 * HOL: 'inductive' no longer features separate (collective) attributes
  4364 for 'intros' (was found too confusing);
  4365 
  4366 * HOL: properly declared induction rules less_induct and
  4367 wf_induct_rule;
  4368 
  4369 
  4370 *** HOL ***
  4371 
  4372 * HOL: moved over to sane numeral syntax; the new policy is as
  4373 follows:
  4374 
  4375   - 0 and 1 are polymorphic constants, which are defined on any
  4376   numeric type (nat, int, real etc.);
  4377 
  4378   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4379   binary representation internally;
  4380 
  4381   - type nat has special constructor Suc, and generally prefers Suc 0
  4382   over 1::nat and Suc (Suc 0) over 2::nat;
  4383 
  4384 This change may cause significant problems of INCOMPATIBILITY; here
  4385 are some hints on converting existing sources:
  4386 
  4387   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4388   entities, so expressions involving "-" (unary or binary minus) need
  4389   to be spaced properly;
  4390 
  4391   - existing occurrences of "1" may need to be constraint "1::nat" or
  4392   even replaced by Suc 0; similar for old "2";
  4393 
  4394   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4395 
  4396   - remove all special provisions on numerals in proofs;
  4397 
  4398 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4399 representation (depends on bin_arith_simps in the default context);
  4400 
  4401 * HOL: symbolic syntax for x^2 (numeral 2);
  4402 
  4403 * HOL: the class of all HOL types is now called "type" rather than
  4404 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4405 in axclass/classes, instance/arities, and (usually rare) occurrences
  4406 in typings (of consts etc.); internally the class is called
  4407 "HOL.type", ML programs should refer to HOLogic.typeS;
  4408 
  4409 * HOL/record package improvements:
  4410   - new derived operations "fields" to build a partial record section,
  4411     "extend" to promote a fixed record to a record scheme, and
  4412     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4413     declared as simp by default;
  4414   - shared operations ("more", "fields", etc.) now need to be always
  4415     qualified) --- potential INCOMPATIBILITY;
  4416   - removed "make_scheme" operations (use "make" with "extend") --
  4417     INCOMPATIBILITY;
  4418   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4419   - provides cases/induct rules for use with corresponding Isar
  4420     methods (for concrete records, record schemes, concrete more
  4421     parts, and schematic more parts -- in that order);
  4422   - internal definitions directly based on a light-weight abstract
  4423     theory of product types over typedef rather than datatype;
  4424 
  4425 * HOL: generic code generator for generating executable ML code from
  4426 specifications; specific support for HOL constructs such as inductive
  4427 datatypes and sets, as well as recursive functions; can be invoked
  4428 via 'generate_code' theory section;
  4429 
  4430 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4431 
  4432 * HOL: consolidated and renamed several theories.  In particular:
  4433         Ord.thy has been absorbed into HOL.thy
  4434         String.thy has been absorbed into List.thy
  4435 
  4436 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4437 (beware of argument permutation!);
  4438 
  4439 * HOL: linorder_less_split superseded by linorder_cases;
  4440 
  4441 * HOL/List: "nodups" renamed to "distinct";
  4442 
  4443 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4444 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4445   - Ex_def has changed, now need to use some_eq_ex
  4446 
  4447 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4448 in this (rare) case use:
  4449 
  4450   delSWrapper "split_all_tac"
  4451   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4452 
  4453 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4454 MAY FAIL;
  4455 
  4456 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4457 Isabelle's type classes, ^ on functions and relations has too general
  4458 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4459 necessary to attach explicit type constraints;
  4460 
  4461 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4462 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4463 renamed accordingly (eg "compI" -> "rel_compI").
  4464 
  4465 * HOL: syntax translations now work properly with numerals and records
  4466 expressions;
  4467 
  4468 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4469 of "lam" -- INCOMPATIBILITY;
  4470 
  4471 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4472 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4473 renamed "Product_Type.unit";
  4474 
  4475 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4476 
  4477 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4478 the "cases" method);
  4479 
  4480 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4481 Florian Kammller);
  4482 
  4483 * HOL/IMP: updated and converted to new-style theory format; several
  4484 parts turned into readable document, with proper Isar proof texts and
  4485 some explanations (by Gerwin Klein);
  4486 
  4487 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4488 
  4489 * HOL-Hyperreal is now a logic image;
  4490 
  4491 
  4492 *** HOLCF ***
  4493 
  4494 * Isar: consts/constdefs supports mixfix syntax for continuous
  4495 operations;
  4496 
  4497 * Isar: domain package adapted to new-style theory format, e.g. see
  4498 HOLCF/ex/Dnat.thy;
  4499 
  4500 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4501 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4502 lift.induct_tac, always use UU instead of Undef;
  4503 
  4504 * HOLCF/IMP: updated and converted to new-style theory;
  4505 
  4506 
  4507 *** ZF ***
  4508 
  4509 * Isar: proper integration of logic-specific tools and packages,
  4510 including theory commands '(co)inductive', '(co)datatype',
  4511 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4512 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4513 
  4514 * theory Main no longer includes AC; for the Axiom of Choice, base
  4515 your theory on Main_ZFC;
  4516 
  4517 * the integer library now covers quotients and remainders, with many
  4518 laws relating division to addition, multiplication, etc.;
  4519 
  4520 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4521 typeless version of the formalism;
  4522 
  4523 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4524 format;
  4525 
  4526 * ZF/Induct: new directory for examples of inductive definitions,
  4527 including theory Multiset for multiset orderings; converted to
  4528 new-style theory format;
  4529 
  4530 * ZF: many new theorems about lists, ordinals, etc.;
  4531 
  4532 
  4533 *** General ***
  4534 
  4535 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4536 variable proof controls level of detail: 0 = no proofs (only oracle
  4537 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4538 also ref manual for further ML interfaces;
  4539 
  4540 * Pure/axclass: removed obsolete ML interface
  4541 goal_subclass/goal_arity;
  4542 
  4543 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4544 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4545 separate tokens, so expressions involving minus need to be spaced
  4546 properly;
  4547 
  4548 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4549 rather than "infixl" or "infixr";
  4550 
  4551 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4552 sort constraint specifications in type inference; e.g. "x::_::foo"
  4553 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4554 type variable);
  4555 
  4556 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4557 control output of nested => (types); the default behavior is
  4558 "type_brackets";
  4559 
  4560 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4561 tokens into AST constants;
  4562 
  4563 * Pure/syntax: prefer later declarations of translations and print
  4564 translation functions; potential INCOMPATIBILITY: need to reverse
  4565 multiple declarations for same syntax element constant;
  4566 
  4567 * Pure/show_hyps reset by default (in accordance to existing Isar
  4568 practice);
  4569 
  4570 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4571 addSafter;
  4572 
  4573 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4574 as well;
  4575 
  4576 * system: tested support for MacOS X; should be able to get Isabelle +
  4577 Proof General to work in a plain Terminal after installing Poly/ML
  4578 (e.g. from the Isabelle distribution area) and GNU bash alone
  4579 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4580 support requires further installations, e.g. from
  4581 http://fink.sourceforge.net/);
  4582 
  4583 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4584 
  4585 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4586 of 40 MB), cf. ML_OPTIONS;
  4587 
  4588 * system: Proof General keywords specification is now part of the
  4589 Isabelle distribution (see etc/isar-keywords.el);
  4590 
  4591 * system: support for persistent Proof General sessions (refrain from
  4592 outdating all loaded theories on startup); user may create writable
  4593 logic images like this: ``isabelle -q HOL Test'';
  4594 
  4595 * system: smart selection of Isabelle process versus Isabelle
  4596 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4597 run both "isabelle" and "Isabelle" even if file names are badly
  4598 damaged (executable inspects the case of the first letter of its own
  4599 name); added separate "isabelle-process" and "isabelle-interface";
  4600 
  4601 * system: refrain from any attempt at filtering input streams; no
  4602 longer support ``8bit'' encoding of old isabelle font, instead proper
  4603 iso-latin characters may now be used; the related isatools
  4604 "symbolinput" and "nonascii" have disappeared as well;
  4605 
  4606 * system: removed old "xterm" interface (the print modes "xterm" and
  4607 "xterm_color" are still available for direct use in a suitable
  4608 terminal);
  4609 
  4610 
  4611 
  4612 New in Isabelle99-2 (February 2001)
  4613 -----------------------------------
  4614 
  4615 *** Overview of INCOMPATIBILITIES ***
  4616 
  4617 * HOL: please note that theories in the Library and elsewhere often use the
  4618 new-style (Isar) format; to refer to their theorems in an ML script you must
  4619 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4620 
  4621 * HOL: inductive package no longer splits induction rule aggressively,
  4622 but only as far as specified by the introductions given; the old
  4623 format may be recovered via ML function complete_split_rule or attribute
  4624 'split_rule (complete)';
  4625 
  4626 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4627 gfp_Tarski to gfp_unfold;
  4628 
  4629 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4630 
  4631 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4632 relation); infix "^^" has been renamed "``"; infix "``" has been
  4633 renamed "`"; "univalent" has been renamed "single_valued";
  4634 
  4635 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4636 operation;
  4637 
  4638 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4639 
  4640 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4641 
  4642 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4643 consequence, it is no longer monotonic wrt. the local goal context
  4644 (which is now passed through the inductive cases);
  4645 
  4646 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4647 \<gg> to \<ggreater>;
  4648 
  4649 
  4650 *** Document preparation ***
  4651 
  4652 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4653 available: are "it" for near math-mode best-style output, "sl" for
  4654 slanted text style, and "tt" for plain type-writer; if no
  4655 \isabellestyle command is given, output is according to slanted
  4656 type-writer);
  4657 
  4658 * support sub/super scripts (for single symbols only), input syntax is
  4659 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4660 
  4661 * some more standard symbols; see Appendix A of the system manual for
  4662 the complete list of symbols defined in isabellesym.sty;
  4663 
  4664 * improved isabelle style files; more abstract symbol implementation
  4665 (should now use \isamath{...} and \isatext{...} in custom symbol
  4666 definitions);
  4667 
  4668 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4669 state; Note that presentation of goal states does not conform to
  4670 actual human-readable proof documents.  Please do not include goal
  4671 states into document output unless you really know what you are doing!
  4672 
  4673 * proper indentation of antiquoted output with proportional LaTeX
  4674 fonts;
  4675 
  4676 * no_document ML operator temporarily disables LaTeX document
  4677 generation;
  4678 
  4679 * isatool unsymbolize tunes sources for plain ASCII communication;
  4680 
  4681 
  4682 *** Isar ***
  4683 
  4684 * Pure: Isar now suffers initial goal statements to contain unbound
  4685 schematic variables (this does not conform to actual readable proof
  4686 documents, due to unpredictable outcome and non-compositional proof
  4687 checking); users who know what they are doing may use schematic goals
  4688 for Prolog-style synthesis of proven results;
  4689 
  4690 * Pure: assumption method (an implicit finishing) now handles actual
  4691 rules as well;
  4692 
  4693 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4694 initial goal, declare "that" only as Pure intro (only for single
  4695 steps); the "that" rule assumption may now be involved in implicit
  4696 finishing, thus ".." becomes a feasible for trivial obtains;
  4697 
  4698 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4699 instance proofs may be performed by "..";
  4700 
  4701 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4702 statements as well;
  4703 
  4704 * Pure: more robust selection of calculational rules;
  4705 
  4706 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4707 rule (as well as the assumption rule);
  4708 
  4709 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4710 lemmas, using the graph browser tool;
  4711 
  4712 * Pure: predict failure of "show" in interactive mode;
  4713 
  4714 * Pure: 'thms_containing' now takes actual terms as arguments;
  4715 
  4716 * HOL: improved method 'induct' --- now handles non-atomic goals
  4717 (potential INCOMPATIBILITY); tuned error handling;
  4718 
  4719 * HOL: cases and induct rules now provide explicit hints about the
  4720 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4721 any remaining facts are inserted into the goal verbatim;
  4722 
  4723 * HOL: local contexts (aka cases) may now contain term bindings as
  4724 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4725 the result to be shown in each case;
  4726 
  4727 * HOL: added 'recdef_tc' command;
  4728 
  4729 * isatool convert assists in eliminating legacy ML scripts;
  4730 
  4731 
  4732 *** HOL ***
  4733 
  4734 * HOL/Library: a collection of generic theories to be used together
  4735 with main HOL; the theory loader path already includes this directory
  4736 by default; the following existing theories have been moved here:
  4737 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4738 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4739 
  4740 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4741 modelling and verification task performed in Isabelle/HOL +
  4742 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4743 
  4744 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4745 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4746 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4747 'domain', this makes the theory consistent with mathematical
  4748 literature;
  4749 
  4750 * HOL basics: added overloaded operations "inverse" and "divide"
  4751 (infix "/"), syntax for generic "abs" operation, generic summation
  4752 operator \<Sum>;
  4753 
  4754 * HOL/typedef: simplified package, provide more useful rules (see also
  4755 HOL/subset.thy);
  4756 
  4757 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4758 now expressed as a proper nested rule (old-style tactic scripts may
  4759 require atomize_strip_tac to cope with non-atomic premises);
  4760 
  4761 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4762 to "split_conv" (old name still available for compatibility);
  4763 
  4764 * HOL: improved concrete syntax for strings (e.g. allows translation
  4765 rules with string literals);
  4766 
  4767 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4768  and Fleuriot's mechanization of analysis, including the transcendental
  4769  functions for the reals;
  4770 
  4771 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4772 
  4773 
  4774 *** CTT ***
  4775 
  4776 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4777 "lam" is displayed as TWO lambda-symbols
  4778 
  4779 * CTT: theory Main now available, containing everything (that is, Bool
  4780 and Arith);
  4781 
  4782 
  4783 *** General ***
  4784 
  4785 * Pure: the Simplifier has been implemented properly as a derived rule
  4786 outside of the actual kernel (at last!); the overall performance
  4787 penalty in practical applications is about 50%, while reliability of
  4788 the Isabelle inference kernel has been greatly improved;
  4789 
  4790 * print modes "brackets" and "no_brackets" control output of nested =>
  4791 (types) and ==> (props); the default behaviour is "brackets";
  4792 
  4793 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4794 as assumptions as well;
  4795 
  4796 * system: support Poly/ML 4.0;
  4797 
  4798 * system: isatool install handles KDE version 1 or 2;
  4799 
  4800 
  4801 
  4802 New in Isabelle99-1 (October 2000)
  4803 ----------------------------------
  4804 
  4805 *** Overview of INCOMPATIBILITIES ***
  4806 
  4807 * HOL: simplification of natural numbers is much changed; to partly
  4808 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4809 issue the following ML commands:
  4810 
  4811   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4812   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4813 
  4814 * HOL: simplification no longer dives into case-expressions; this is
  4815 controlled by "t.weak_case_cong" for each datatype t;
  4816 
  4817 * HOL: nat_less_induct renamed to less_induct;
  4818 
  4819 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4820 fixsome to patch .thy and .ML sources automatically;
  4821 
  4822   select_equality  -> some_equality
  4823   select_eq_Ex     -> some_eq_ex
  4824   selectI2EX       -> someI2_ex
  4825   selectI2         -> someI2
  4826   selectI          -> someI
  4827   select1_equality -> some1_equality
  4828   Eps_sym_eq       -> some_sym_eq_trivial
  4829   Eps_eq           -> some_eq_trivial
  4830 
  4831 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4832 
  4833 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4834 instead);
  4835 
  4836 * HOL: the recursion equations generated by 'recdef' are now called
  4837 f.simps instead of f.rules;
  4838 
  4839 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4840 
  4841 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4842 sometimes be needed;
  4843 
  4844 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4845 
  4846 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4847 
  4848 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4849 product is now "<*>" instead of "Times"; the lexicographic product is
  4850 now "<*lex*>" instead of "**";
  4851 
  4852 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4853 of main HOL, but was unused); better use HOL's datatype package;
  4854 
  4855 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4856 the old syntax may be recovered as follows:
  4857 
  4858   syntax (symbols)
  4859     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4860       (infixl "\\<oplus>" 100)
  4861 
  4862 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4863 
  4864 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4865 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4866 internally;
  4867 
  4868 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4869 changed from A/r to A//r;
  4870 
  4871 * ZF: new treatment of arithmetic (nat & int) may break some old
  4872 proofs;
  4873 
  4874 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4875 rulify -> rule_format, elimify -> elim_format, ...);
  4876 
  4877 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4878 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4879 should have to change intro!! to intro? only); replaced "delrule" by
  4880 "rule del";
  4881 
  4882 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4883 
  4884 * Provers: strengthened force_tac by using new first_best_tac;
  4885 
  4886 * LaTeX document preparation: several changes of isabelle.sty (see
  4887 lib/texinputs);
  4888 
  4889 
  4890 *** Document preparation ***
  4891 
  4892 * formal comments (text blocks etc.) in new-style theories may now
  4893 contain antiquotations of thm/prop/term/typ/text to be presented
  4894 according to latex print mode; concrete syntax is like this:
  4895 @{term[show_types] "f(x) = a + x"};
  4896 
  4897 * isatool mkdir provides easy setup of Isabelle session directories,
  4898 including proper document sources;
  4899 
  4900 * generated LaTeX sources are now deleted after successful run
  4901 (isatool document -c); may retain a copy somewhere else via -D option
  4902 of isatool usedir;
  4903 
  4904 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4905 style files, achieving self-contained LaTeX sources and simplifying
  4906 LaTeX debugging;
  4907 
  4908 * old-style theories now produce (crude) LaTeX output as well;
  4909 
  4910 * browser info session directories are now self-contained (may be put
  4911 on WWW server seperately); improved graphs of nested sessions; removed
  4912 graph for 'all sessions';
  4913 
  4914 * several improvements in isabelle style files; \isabellestyle{it}
  4915 produces fake math mode output; \isamarkupheader is now \section by
  4916 default; see lib/texinputs/isabelle.sty etc.;
  4917 
  4918 
  4919 *** Isar ***
  4920 
  4921 * Isar/Pure: local results and corresponding term bindings are now
  4922 subject to Hindley-Milner polymorphism (similar to ML); this
  4923 accommodates incremental type-inference very nicely;
  4924 
  4925 * Isar/Pure: new derived language element 'obtain' supports
  4926 generalized existence reasoning;
  4927 
  4928 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4929 support accumulation of results, without applying any rules yet;
  4930 useful to collect intermediate results without explicit name
  4931 references, and for use with transitivity rules with more than 2
  4932 premises;
  4933 
  4934 * Isar/Pure: scalable support for case-analysis type proofs: new
  4935 'case' language element refers to local contexts symbolically, as
  4936 produced by certain proof methods; internally, case names are attached
  4937 to theorems as "tags";
  4938 
  4939 * Isar/Pure: theory command 'hide' removes declarations from
  4940 class/type/const name spaces;
  4941 
  4942 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4943 indicate potential overloading;
  4944 
  4945 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4946 
  4947 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4948 "{a,b,c}" instead of {a,b,c};
  4949 
  4950 * Isar/Pure now provides its own version of intro/elim/dest
  4951 attributes; useful for building new logics, but beware of confusion
  4952 with the version in Provers/classical;
  4953 
  4954 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4955 case name 'antecedent';
  4956 
  4957 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4958 to the current context is now done automatically);
  4959 
  4960 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4961 for definining proof methods in ML;
  4962 
  4963 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4964 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4965 most cases, one should have to change intro!! to intro? only);
  4966 replaced "delrule" by "rule del";
  4967 
  4968 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4969 'symmetric' attribute (the latter supercedes [RS sym]);
  4970 
  4971 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4972 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4973 well (including splits);
  4974 
  4975 * Isar/Provers: Simplifier and Classical methods now support all kind
  4976 of modifiers used in the past, including 'cong', 'iff', etc.
  4977 
  4978 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4979 of Simplifier and Classical reasoner);
  4980 
  4981 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4982 now support named cases; major packages (inductive, datatype, primrec,
  4983 recdef) support case names and properly name parameters;
  4984 
  4985 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4986 monotonicity conditions are extracted to be proven at end of
  4987 calculations;
  4988 
  4989 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4990 method anyway;
  4991 
  4992 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4993 split_if split_if_asm; datatype package provides theorems foo.splits =
  4994 foo.split foo.split_asm for each datatype;
  4995 
  4996 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4997 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4998 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4999 use "(cases (simplified))" method in proper proof texts);
  5000 
  5001 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  5002 
  5003 * Isar: names of theorems etc. may be natural numbers as well;
  5004 
  5005 * Isar: 'pr' command: optional arguments for goals_limit and
  5006 ProofContext.prems_limit; no longer prints theory contexts, but only
  5007 proof states;
  5008 
  5009 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  5010 additional print modes to be specified; e.g. "pr(latex)" will print
  5011 proof state according to the Isabelle LaTeX style;
  5012 
  5013 * Isar: improved support for emulating tactic scripts, including proof
  5014 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  5015 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  5016 (for HOL datatypes);
  5017 
  5018 * Isar: simplified (more robust) goal selection of proof methods: 1st
  5019 goal, all goals, or explicit goal specifier (tactic emulation); thus
  5020 'proof method scripts' have to be in depth-first order;
  5021 
  5022 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  5023 
  5024 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  5025 should instead use individual commands for printing items
  5026 (print_commands, print_methods etc.);
  5027 
  5028 * Isar: added 'nothing' --- the empty list of theorems;
  5029 
  5030 
  5031 *** HOL ***
  5032 
  5033 * HOL/MicroJava: formalization of a fragment of Java, together with a
  5034 corresponding virtual machine and a specification of its bytecode
  5035 verifier and a lightweight bytecode verifier, including proofs of
  5036 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  5037 Cornelia Pusch (see also the homepage of project Bali at
  5038 http://isabelle.in.tum.de/Bali/);
  5039 
  5040 * HOL/Algebra: new theory of rings and univariate polynomials, by
  5041 Clemens Ballarin;
  5042 
  5043 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  5044 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  5045 Rasmussen;
  5046 
  5047 * HOL/Lattice: fundamental concepts of lattice theory and order
  5048 structures, including duals, properties of bounds versus algebraic
  5049 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  5050 Theorem for complete lattices etc.; may also serve as a demonstration
  5051 for abstract algebraic reasoning using axiomatic type classes, and
  5052 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  5053 
  5054 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  5055 von Oheimb;
  5056 
  5057 * HOL/IMPP: extension of IMP with local variables and mutually
  5058 recursive procedures, by David von Oheimb;
  5059 
  5060 * HOL/Lambda: converted into new-style theory and document;
  5061 
  5062 * HOL/ex/Multiquote: example of multiple nested quotations and
  5063 anti-quotations -- basically a generalized version of de-Bruijn
  5064 representation; very useful in avoiding lifting of operations;
  5065 
  5066 * HOL/record: added general record equality rule to simpset; fixed
  5067 select-update simplification procedure to handle extended records as
  5068 well; admit "r" as field name;
  5069 
  5070 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  5071 other numeric types and also as the identity of groups, rings, etc.;
  5072 
  5073 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  5074 Types nat and int belong to this axclass;
  5075 
  5076 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  5077    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  5078    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  5079   two terms #m*u and #n*u are replaced by #(m+n)*u
  5080     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  5081   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  5082     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  5083 
  5084 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  5085 powerful prover for predicate logic but knows nothing of clasets; see
  5086 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  5087 
  5088 * HOL: new version of "case_tac" subsumes both boolean case split and
  5089 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  5090 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  5091 
  5092 * HOL: simplification no longer dives into case-expressions: only the
  5093 selector expression is simplified, but not the remaining arms; to
  5094 enable full simplification of case-expressions for datatype t, you may
  5095 remove t.weak_case_cong from the simpset, either globally (Delcongs
  5096 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  5097 
  5098 * HOL/recdef: the recursion equations generated by 'recdef' for
  5099 function 'f' are now called f.simps instead of f.rules; if all
  5100 termination conditions are proved automatically, these simplification
  5101 rules are added to the simpset, as in primrec; rules may be named
  5102 individually as well, resulting in a separate list of theorems for
  5103 each equation;
  5104 
  5105 * HOL/While is a new theory that provides a while-combinator. It
  5106 permits the definition of tail-recursive functions without the
  5107 provision of a termination measure. The latter is necessary once the
  5108 invariant proof rule for while is applied.
  5109 
  5110 * HOL: new (overloaded) notation for the set of elements below/above
  5111 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5112 
  5113 * HOL: theorems impI, allI, ballI bound as "strip";
  5114 
  5115 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5116 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5117 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5118 
  5119 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5120 
  5121 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5122 main HOL, but was unused);
  5123 
  5124 * HOL: fewer consts declared as global (e.g. have to refer to
  5125 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5126 
  5127 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5128 in case of overlap with user translations (e.g. judgements over
  5129 tuples); (note that the underlying logical represenation is still
  5130 bogus);
  5131 
  5132 
  5133 *** ZF ***
  5134 
  5135 * ZF: simplification automatically cancels common terms in arithmetic
  5136 expressions over nat and int;
  5137 
  5138 * ZF: new treatment of nat to minimize type-checking: all operators
  5139 coerce their operands to a natural number using the function natify,
  5140 making the algebraic laws unconditional;
  5141 
  5142 * ZF: as above, for int: operators coerce their operands to an integer
  5143 using the function intify;
  5144 
  5145 * ZF: the integer library now contains many of the usual laws for the
  5146 orderings, including $<=, and monotonicity laws for $+ and $*;
  5147 
  5148 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5149 simplification;
  5150 
  5151 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5152 to the simplifier and classical reasoner simultaneously;
  5153 
  5154 
  5155 *** General ***
  5156 
  5157 * Provers: blast_tac now handles actual object-logic rules as
  5158 assumptions; note that auto_tac uses blast_tac internally as well;
  5159 
  5160 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5161 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5162 
  5163 * Provers: delrules now handles destruct rules as well (no longer need
  5164 explicit make_elim);
  5165 
  5166 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5167   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5168 use instead the strong form,
  5169   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5170 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5171 from destruct-rules;
  5172 
  5173 * Provers: Simplifier.easy_setup provides a fast path to basic
  5174 Simplifier setup for new object-logics;
  5175 
  5176 * Pure: AST translation rules no longer require constant head on LHS;
  5177 
  5178 * Pure: improved name spaces: ambiguous output is qualified; support
  5179 for hiding of names;
  5180 
  5181 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5182 XSYMBOL_HOME; no longer need to do manual configuration in most
  5183 situations;
  5184 
  5185 * system: compression of ML heaps images may now be controlled via -c
  5186 option of isabelle and isatool usedir (currently only observed by
  5187 Poly/ML);
  5188 
  5189 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5190 useful for remote X11);
  5191 
  5192 * system: provide TAGS file for Isabelle sources;
  5193 
  5194 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5195 order;
  5196 
  5197 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5198 timing flag supersedes proof_timing and Toplevel.trace;
  5199 
  5200 * ML: new combinators |>> and |>>> for incremental transformations
  5201 with secondary results (e.g. certain theory extensions):
  5202 
  5203 * ML: PureThy.add_defs gets additional argument to indicate potential
  5204 overloading (usually false);
  5205 
  5206 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5207 results;
  5208 
  5209 
  5210 
  5211 New in Isabelle99 (October 1999)
  5212 --------------------------------
  5213 
  5214 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5215 
  5216 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5217 are no longer simplified.  (This allows the simplifier to unfold recursive
  5218 functional programs.)  To restore the old behaviour, declare
  5219 
  5220     Delcongs [if_weak_cong];
  5221 
  5222 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5223 complement;
  5224 
  5225 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5226 
  5227 * HOL/datatype: mutual_induct_tac no longer exists --
  5228   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5229 
  5230 * HOL/typedef: fixed type inference for representing set; type
  5231 arguments now have to occur explicitly on the rhs as type constraints;
  5232 
  5233 * ZF: The con_defs part of an inductive definition may no longer refer
  5234 to constants declared in the same theory;
  5235 
  5236 * HOL, ZF: the function mk_cases, generated by the inductive
  5237 definition package, has lost an argument.  To simplify its result, it
  5238 uses the default simpset instead of a supplied list of theorems.
  5239 
  5240 * HOL/List: the constructors of type list are now Nil and Cons;
  5241 
  5242 * Simplifier: the type of the infix ML functions
  5243         setSSolver addSSolver setSolver addSolver
  5244 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5245 for packaging solvers. A solver is created via
  5246         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5247 where the string argument is only a comment.
  5248 
  5249 
  5250 *** Proof tools ***
  5251 
  5252 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5253 decision procedure for linear arithmetic. Currently it is used for
  5254 types `nat', `int', and `real' in HOL (see below); it can, should and
  5255 will be instantiated for other types and logics as well.
  5256 
  5257 * The simplifier now accepts rewrite rules with flexible heads, eg
  5258      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5259   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5260   matching.
  5261 
  5262 
  5263 *** General ***
  5264 
  5265 * New Isabelle/Isar subsystem provides an alternative to traditional
  5266 tactical theorem proving; together with the ProofGeneral/isar user
  5267 interface it offers an interactive environment for developing human
  5268 readable proof documents (Isar == Intelligible semi-automated
  5269 reasoning); for further information see isatool doc isar-ref,
  5270 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5271 
  5272 * improved and simplified presentation of theories: better HTML markup
  5273 (including colors), graph views in several sizes; isatool usedir now
  5274 provides a proper interface for user theories (via -P option); actual
  5275 document preparation based on (PDF)LaTeX is available as well (for
  5276 new-style theories only); see isatool doc system for more information;
  5277 
  5278 * native support for Proof General, both for classic Isabelle and
  5279 Isabelle/Isar;
  5280 
  5281 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5282 using the graph browser tool;
  5283 
  5284 * Isabelle manuals now also available as PDF;
  5285 
  5286 * theory loader rewritten from scratch (may not be fully
  5287 bug-compatible); old loadpath variable has been replaced by show_path,
  5288 add_path, del_path, reset_path functions; new operations such as
  5289 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5290 isatool doc ref);
  5291 
  5292 * improved isatool install: option -k creates KDE application icon,
  5293 option -p DIR installs standalone binaries;
  5294 
  5295 * added ML_PLATFORM setting (useful for cross-platform installations);
  5296 more robust handling of platform specific ML images for SML/NJ;
  5297 
  5298 * the settings environment is now statically scoped, i.e. it is never
  5299 created again in sub-processes invoked from isabelle, isatool, or
  5300 Isabelle;
  5301 
  5302 * path element specification '~~' refers to '$ISABELLE_HOME';
  5303 
  5304 * in locales, the "assumes" and "defines" parts may be omitted if
  5305 empty;
  5306 
  5307 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5308 long arrows);
  5309 
  5310 * new print_mode "HTML";
  5311 
  5312 * new flag show_tags controls display of tags of theorems (which are
  5313 basically just comments that may be attached by some tools);
  5314 
  5315 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5316 mode and goal output format:
  5317 
  5318 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5319 244c244
  5320 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5321 ---
  5322 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5323 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5324 181c181
  5325 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5326 ---
  5327 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5328 
  5329 * function bind_thms stores lists of theorems (cf. bind_thm);
  5330 
  5331 * new shorthand tactics ftac, eatac, datac, fatac;
  5332 
  5333 * qed (and friends) now accept "" as result name; in that case the
  5334 theorem is not stored, but proper checks and presentation of the
  5335 result still apply;
  5336 
  5337 * theorem database now also indexes constants "Trueprop", "all",
  5338 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5339 
  5340 
  5341 *** HOL ***
  5342 
  5343 ** HOL arithmetic **
  5344 
  5345 * There are now decision procedures for linear arithmetic over nat and
  5346 int:
  5347 
  5348 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5349 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5350 are treated as atomic; subformulae not involving type `nat' or `int'
  5351 are ignored; quantified subformulae are ignored unless they are
  5352 positive universal or negative existential. The tactic has to be
  5353 invoked by hand and can be a little bit slow. In particular, the
  5354 running time is exponential in the number of occurrences of `min' and
  5355 `max', and `-' on `nat'.
  5356 
  5357 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5358 (negated) (in)equalities among the premises and the conclusion into
  5359 account (i.e. no compound formulae) and does not know about `min' and
  5360 `max', and `-' on `nat'. It is fast and is used automatically by the
  5361 simplifier.
  5362 
  5363 NB: At the moment, these decision procedures do not cope with mixed
  5364 nat/int formulae where the two parts interact, such as `m < n ==>
  5365 int(m) < int(n)'.
  5366 
  5367 * HOL/Numeral provides a generic theory of numerals (encoded
  5368 efficiently as bit strings); setup for types nat/int/real is in place;
  5369 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5370 int, existing theories and proof scripts may require a few additional
  5371 type constraints;
  5372 
  5373 * integer division and remainder can now be performed on constant
  5374 arguments;
  5375 
  5376 * many properties of integer multiplication, division and remainder
  5377 are now available;
  5378 
  5379 * An interface to the Stanford Validity Checker (SVC) is available through the
  5380 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5381 are proved automatically.  SVC must be installed separately, and its results
  5382 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5383 invocation of the underlying oracle).  For SVC see
  5384   http://verify.stanford.edu/SVC
  5385 
  5386 * IsaMakefile: the HOL-Real target now builds an actual image;
  5387 
  5388 
  5389 ** HOL misc **
  5390 
  5391 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5392 (in Isabelle/Isar) -- by Gertrud Bauer;
  5393 
  5394 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5395 analysis for assembly languages with subtypes;
  5396 
  5397 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5398 -- avoids syntactic ambiguities and treats state, transition, and
  5399 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5400 changed syntax and (many) tactics;
  5401 
  5402 * HOL/inductive: Now also handles more general introduction rules such
  5403   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5404   theorems are now maintained within the theory (maintained via the
  5405   "mono" attribute);
  5406 
  5407 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5408   (using function types) such as
  5409 
  5410   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5411 
  5412 * HOL/record: record_simproc (part of the default simpset) takes care
  5413 of selectors applied to updated records; record_split_tac is no longer
  5414 part of the default claset; update_defs may now be removed from the
  5415 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5416 
  5417   claset_ref () := claset() addSWrapper record_split_wrapper;
  5418   Delsimprocs [record_simproc]
  5419 
  5420 * HOL/typedef: fixed type inference for representing set; type
  5421 arguments now have to occur explicitly on the rhs as type constraints;
  5422 
  5423 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5424 names rather than an ML expression;
  5425 
  5426 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5427 supplied later.  Program schemes can be defined, such as
  5428     "While B C s = (if B s then While B C (C s) else s)"
  5429 where the well-founded relation can be chosen after B and C have been given.
  5430 
  5431 * HOL/List: the constructors of type list are now Nil and Cons;
  5432 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5433 course, ML tools referring to List.list.op # etc. have to be adapted;
  5434 
  5435 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5436 disabled by default; run isabelle with option -m HOL to get back to
  5437 the original Gordon/HOL-style output;
  5438 
  5439 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5440 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5441 
  5442 * HOL basic syntax simplified (more orthogonal): all variants of
  5443 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5444 Eps operator is provided as well: "SOME x. P[x]";
  5445 
  5446 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5447 
  5448 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5449 thus available for user theories;
  5450 
  5451 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5452 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5453 time;
  5454 
  5455 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5456 several times and then mp;
  5457 
  5458 
  5459 *** LK ***
  5460 
  5461 * the notation <<...>> is now available as a notation for sequences of
  5462 formulas;
  5463 
  5464 * the simplifier is now installed
  5465 
  5466 * the axiom system has been generalized (thanks to Soren Heilmann)
  5467 
  5468 * the classical reasoner now has a default rule database
  5469 
  5470 
  5471 *** ZF ***
  5472 
  5473 * new primrec section allows primitive recursive functions to be given
  5474 directly (as in HOL) over datatypes and the natural numbers;
  5475 
  5476 * new tactics induct_tac and exhaust_tac for induction (or case
  5477 analysis) over datatypes and the natural numbers;
  5478 
  5479 * the datatype declaration of type T now defines the recursor T_rec;
  5480 
  5481 * simplification automatically does freeness reasoning for datatype
  5482 constructors;
  5483 
  5484 * automatic type-inference, with AddTCs command to insert new
  5485 type-checking rules;
  5486 
  5487 * datatype introduction rules are now added as Safe Introduction rules
  5488 to the claset;
  5489 
  5490 * the syntax "if P then x else y" is now available in addition to
  5491 if(P,x,y);
  5492 
  5493 
  5494 *** Internal programming interfaces ***
  5495 
  5496 * tuned simplifier trace output; new flag debug_simp;
  5497 
  5498 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5499 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5500 
  5501 * AxClass.axclass_tac lost the theory argument;
  5502 
  5503 * tuned current_goals_markers semantics: begin / end goal avoids
  5504 printing empty lines;
  5505 
  5506 * removed prs and prs_fn hook, which was broken because it did not
  5507 include \n in its semantics, forcing writeln to add one
  5508 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5509 string -> unit if you really want to output text without newline;
  5510 
  5511 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5512 plain output, interface builders may have to enable 'isabelle_font'
  5513 mode to get Isabelle font glyphs as before;
  5514 
  5515 * refined token_translation interface; INCOMPATIBILITY: output length
  5516 now of type real instead of int;
  5517 
  5518 * theory loader actions may be traced via new ThyInfo.add_hook
  5519 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5520 your own database of information attached to *whole* theories -- as
  5521 opposed to intra-theory data slots offered via TheoryDataFun;
  5522 
  5523 * proper handling of dangling sort hypotheses (at last!);
  5524 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5525 extra sort hypotheses that can be witnessed from the type signature;
  5526 the force_strip_shyps flag is gone, any remaining shyps are simply
  5527 left in the theorem (with a warning issued by strip_shyps_warning);
  5528 
  5529 
  5530 
  5531 New in Isabelle98-1 (October 1998)
  5532 ----------------------------------
  5533 
  5534 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5535 
  5536 * several changes of automated proof tools;
  5537 
  5538 * HOL: major changes to the inductive and datatype packages, including
  5539 some minor incompatibilities of theory syntax;
  5540 
  5541 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5542 called `inj_on';
  5543 
  5544 * HOL: removed duplicate thms in Arith:
  5545   less_imp_add_less  should be replaced by  trans_less_add1
  5546   le_imp_add_le      should be replaced by  trans_le_add1
  5547 
  5548 * HOL: unary minus is now overloaded (new type constraints may be
  5549 required);
  5550 
  5551 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5552 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5553 now taken as an integer constant.
  5554 
  5555 * Pure: ML function 'theory_of' renamed to 'theory';
  5556 
  5557 
  5558 *** Proof tools ***
  5559 
  5560 * Simplifier:
  5561   1. Asm_full_simp_tac is now more aggressive.
  5562      1. It will sometimes reorient premises if that increases their power to
  5563         simplify.
  5564      2. It does no longer proceed strictly from left to right but may also
  5565         rotate premises to achieve further simplification.
  5566      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5567      old Asm_full_simp_tac in that it does not rotate premises.
  5568   2. The simplifier now knows a little bit about nat-arithmetic.
  5569 
  5570 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5571 allows for selected deletion of wrappers, by introduction of names for
  5572 wrapper functionals.  This implies that addbefore, addSbefore,
  5573 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5574 and that adding two tactics with the same name overwrites the first
  5575 one (emitting a warning).
  5576   type wrapper = (int -> tactic) -> (int -> tactic)
  5577   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5578   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5579   delWrapper, delSWrapper: claset *  string            -> claset
  5580   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5581 
  5582 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5583 semantics; addbefore now affects only the unsafe part of step_tac
  5584 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5585 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5586 by Force_tac;
  5587 
  5588 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5589 compWrapper; added safe wrapper (and access functions for it);
  5590 
  5591 * HOL/split_all_tac is now much faster and fails if there is nothing
  5592 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5593 and the names of the automatically generated variables have changed.
  5594 split_all_tac has moved within claset() from unsafe wrappers to safe
  5595 wrappers, which means that !!-bound variables are split much more
  5596 aggressively, and safe_tac and clarify_tac now split such variables.
  5597 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5598 Note: the same holds for record_split_tac, which does the job of
  5599 split_all_tac for record fields.
  5600 
  5601 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5602 permanently to the default simpset using Addsplits just like
  5603 Addsimps. They can be removed via Delsplits just like
  5604 Delsimps. Lower-case versions are also available.
  5605 
  5606 * HOL/Simplifier: The rule split_if is now part of the default
  5607 simpset. This means that the simplifier will eliminate all occurrences
  5608 of if-then-else in the conclusion of a goal. To prevent this, you can
  5609 either remove split_if completely from the default simpset by
  5610 `Delsplits [split_if]' or remove it in a specific call of the
  5611 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5612 other case splitting rules to/from the default simpset: every datatype
  5613 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5614 t is the name of the datatype).
  5615 
  5616 * Classical reasoner / Simplifier combination: new force_tac (and
  5617 derivatives Force_tac, force) combines rewriting and classical
  5618 reasoning (and whatever other tools) similarly to auto_tac, but is
  5619 aimed to solve the given subgoal completely.
  5620 
  5621 
  5622 *** General ***
  5623 
  5624 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5625 and `goalw': the theory is no longer needed as an explicit argument -
  5626 the current theory context is used; assumptions are no longer returned
  5627 at the ML-level unless one of them starts with ==> or !!; it is
  5628 recommended to convert to these new commands using isatool fixgoal
  5629 (backup your sources first!);
  5630 
  5631 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5632 the current theory context, and 'theory' to lookup stored theories;
  5633 
  5634 * new theory section 'locale' for declaring constants, assumptions and
  5635 definitions that have local scope;
  5636 
  5637 * new theory section 'nonterminals' for purely syntactic types;
  5638 
  5639 * new theory section 'setup' for generic ML setup functions
  5640 (e.g. package initialization);
  5641 
  5642 * the distribution now includes Isabelle icons: see
  5643 lib/logo/isabelle-{small,tiny}.xpm;
  5644 
  5645 * isatool install - install binaries with absolute references to
  5646 ISABELLE_HOME/bin;
  5647 
  5648 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5649 
  5650 * print mode 'emacs' reserved for Isamode;
  5651 
  5652 * support multiple print (ast) translations per constant name;
  5653 
  5654 * theorems involving oracles are now printed with a suffixed [!];
  5655 
  5656 
  5657 *** HOL ***
  5658 
  5659 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5660 
  5661 * HOL/inductive package reorganized and improved: now supports mutual
  5662 definitions such as
  5663 
  5664   inductive EVEN ODD
  5665     intrs
  5666       null "0 : EVEN"
  5667       oddI "n : EVEN ==> Suc n : ODD"
  5668       evenI "n : ODD ==> Suc n : EVEN"
  5669 
  5670 new theorem list "elims" contains an elimination rule for each of the
  5671 recursive sets; inductive definitions now handle disjunctive premises
  5672 correctly (also ZF);
  5673 
  5674 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5675 "mutual_induct" no longer exists - the induction rule is always
  5676 contained in "induct";
  5677 
  5678 
  5679 * HOL/datatype package re-implemented and greatly improved: now
  5680 supports mutually recursive datatypes such as
  5681 
  5682   datatype
  5683     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5684             | SUM ('a aexp) ('a aexp)
  5685             | DIFF ('a aexp) ('a aexp)
  5686             | NUM 'a
  5687   and
  5688     'a bexp = LESS ('a aexp) ('a aexp)
  5689             | AND ('a bexp) ('a bexp)
  5690             | OR ('a bexp) ('a bexp)
  5691 
  5692 as well as indirectly recursive datatypes such as
  5693 
  5694   datatype
  5695     ('a, 'b) term = Var 'a
  5696                   | App 'b ((('a, 'b) term) list)
  5697 
  5698 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5699 induction on mutually / indirectly recursive datatypes.
  5700 
  5701 Primrec equations are now stored in theory and can be accessed via
  5702 <function_name>.simps.
  5703 
  5704 INCOMPATIBILITIES:
  5705 
  5706   - Theories using datatypes must now have theory Datatype as an
  5707     ancestor.
  5708   - The specific <typename>.induct_tac no longer exists - use the
  5709     generic induct_tac instead.
  5710   - natE has been renamed to nat.exhaust - use exhaust_tac
  5711     instead of res_inst_tac ... natE. Note that the variable
  5712     names in nat.exhaust differ from the names in natE, this
  5713     may cause some "fragile" proofs to fail.
  5714   - The theorems split_<typename>_case and split_<typename>_case_asm
  5715     have been renamed to <typename>.split and <typename>.split_asm.
  5716   - Since default sorts of type variables are now handled correctly,
  5717     some datatype definitions may have to be annotated with explicit
  5718     sort constraints.
  5719   - Primrec definitions no longer require function name and type
  5720     of recursive argument.
  5721 
  5722 Consider using isatool fixdatatype to adapt your theories and proof
  5723 scripts to the new package (backup your sources first!).
  5724 
  5725 
  5726 * HOL/record package: considerably improved implementation; now
  5727 includes concrete syntax for record types, terms, updates; theorems
  5728 for surjective pairing and splitting !!-bound record variables; proof
  5729 support is as follows:
  5730 
  5731   1) standard conversions (selectors or updates applied to record
  5732 constructor terms) are part of the standard simpset;
  5733 
  5734   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5735 made part of standard simpset and claset via addIffs;
  5736 
  5737   3) a tactic for record field splitting (record_split_tac) is part of
  5738 the standard claset (addSWrapper);
  5739 
  5740 To get a better idea about these rules you may retrieve them via
  5741 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5742 the name of your record type.
  5743 
  5744 The split tactic 3) conceptually simplifies by the following rule:
  5745 
  5746   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5747 
  5748 Thus any record variable that is bound by meta-all will automatically
  5749 blow up into some record constructor term, consequently the
  5750 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5751 solve record problems automatically.
  5752 
  5753 
  5754 * reorganized the main HOL image: HOL/Integ and String loaded by
  5755 default; theory Main includes everything;
  5756 
  5757 * automatic simplification of integer sums and comparisons, using cancellation;
  5758 
  5759 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5760 
  5761 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5762 
  5763 * many new identities for unions, intersections, set difference, etc.;
  5764 
  5765 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5766 called split_if, split_split, split_sum_case and split_nat_case (to go
  5767 with add/delsplits);
  5768 
  5769 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5770 (?x::unit) = (); this is made part of the default simpset, which COULD
  5771 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5772 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5773 unit_abs_eta_conv is added in order to counter the effect of
  5774 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5775 %u.f();
  5776 
  5777 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5778 makes more sense);
  5779 
  5780 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5781   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5782   disjointness reasoning but breaking a few old proofs.
  5783 
  5784 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5785 to 'converse' from 'inverse' (for compatibility with ZF and some
  5786 literature);
  5787 
  5788 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5789 the well-founded relation;
  5790 
  5791 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5792     Compl A.  The "Compl" syntax remains available as input syntax for this
  5793     release ONLY.
  5794 
  5795 * HOL/Update: new theory of function updates:
  5796     f(a:=b) == %x. if x=a then b else f x
  5797 may also be iterated as in f(a:=b,c:=d,...);
  5798 
  5799 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5800 
  5801 * HOL/List:
  5802   - new function list_update written xs[i:=v] that updates the i-th
  5803     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5804   - new function `upt' written [i..j(] which generates the list
  5805     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5806     bound write [i..j], which is a shorthand for [i..j+1(].
  5807   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5808 
  5809 * HOL/Arith:
  5810   - removed 'pred' (predecessor) function;
  5811   - generalized some theorems about n-1;
  5812   - many new laws about "div" and "mod";
  5813   - new laws about greatest common divisors (see theory ex/Primes);
  5814 
  5815 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5816 instead of "inverse";
  5817 
  5818 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5819   of the multiset ordering;
  5820 
  5821 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5822   (not included by default);
  5823 
  5824 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5825 
  5826 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5827   programs, i.e. different program variables may have different types.
  5828 
  5829 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5830   [previously, this check worked only if the rewrite rule was unconditional]
  5831   Now rew can involve either definitions or equalities (either == or =).
  5832 
  5833 
  5834 *** ZF ***
  5835 
  5836 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5837   only the theorems proved on ZF.ML;
  5838 
  5839 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5840   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5841   disjointness reasoning but breaking a few old proofs.
  5842 
  5843 * ZF/Update: new theory of function updates
  5844     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5845   may also be iterated as in f(a:=b,c:=d,...);
  5846 
  5847 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5848 
  5849 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5850   [previously, this check worked only if the rewrite rule was unconditional]
  5851   Now rew can involve either definitions or equalities (either == or =).
  5852 
  5853 * case_tac provided for compatibility with HOL
  5854     (like the old excluded_middle_tac, but with subgoals swapped)
  5855 
  5856 
  5857 *** Internal programming interfaces ***
  5858 
  5859 * Pure: several new basic modules made available for general use, see
  5860 also src/Pure/README;
  5861 
  5862 * improved the theory data mechanism to support encapsulation (data
  5863 kind name replaced by private Object.kind, acting as authorization
  5864 key); new type-safe user interface via functor TheoryDataFun; generic
  5865 print_data function becomes basically useless;
  5866 
  5867 * removed global_names compatibility flag -- all theory declarations
  5868 are qualified by default;
  5869 
  5870 * module Pure/Syntax now offers quote / antiquote translation
  5871 functions (useful for Hoare logic etc. with implicit dependencies);
  5872 see HOL/ex/Antiquote for an example use;
  5873 
  5874 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5875 cterm -> thm;
  5876 
  5877 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5878 subgoal;
  5879 
  5880 * Display.print_goals function moved to Locale.print_goals;
  5881 
  5882 * standard print function for goals supports current_goals_markers
  5883 variable for marking begin of proof, end of proof, start of goal; the
  5884 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5885 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5886 for example;
  5887 
  5888 
  5889 
  5890 New in Isabelle98 (January 1998)
  5891 --------------------------------
  5892 
  5893 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5894 
  5895 * changed lexical syntax of terms / types: dots made part of long
  5896 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5897 
  5898 * simpset (and claset) reference variable replaced by functions
  5899 simpset / simpset_ref;
  5900 
  5901 * no longer supports theory aliases (via merge) and non-trivial
  5902 implicit merge of thms' signatures;
  5903 
  5904 * most internal names of constants changed due to qualified names;
  5905 
  5906 * changed Pure/Sequence interface (see Pure/seq.ML);
  5907 
  5908 
  5909 *** General Changes ***
  5910 
  5911 * hierachically structured name spaces (for consts, types, axms, thms
  5912 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5913 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5914 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5915 long_names for fully qualified output names; NOTE: ML programs
  5916 (special tactics, packages etc.) referring to internal names may have
  5917 to be adapted to cope with fully qualified names; in case of severe
  5918 backward campatibility problems try setting 'global_names' at compile
  5919 time to have enrything declared within a flat name space; one may also
  5920 fine tune name declarations in theories via the 'global' and 'local'
  5921 section;
  5922 
  5923 * reimplemented the implicit simpset and claset using the new anytype
  5924 data filed in signatures; references simpset:simpset ref etc. are
  5925 replaced by functions simpset:unit->simpset and
  5926 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5927 to patch your ML files accordingly;
  5928 
  5929 * HTML output now includes theory graph data for display with Java
  5930 applet or isatool browser; data generated automatically via isatool
  5931 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5932 
  5933 * defs may now be conditional; improved rewrite_goals_tac to handle
  5934 conditional equations;
  5935 
  5936 * defs now admits additional type arguments, using TYPE('a) syntax;
  5937 
  5938 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5939 creates a new theory node; implicit merge of thms' signatures is
  5940 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5941 transfer:theory->thm->thm in (rare) cases;
  5942 
  5943 * improved handling of draft signatures / theories; draft thms (and
  5944 ctyps, cterms) are automatically promoted to real ones;
  5945 
  5946 * slightly changed interfaces for oracles: admit many per theory, named
  5947 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5948 
  5949 * print_goals: optional output of const types (set show_consts and
  5950 show_types);
  5951 
  5952 * improved output of warnings (###) and errors (***);
  5953 
  5954 * subgoal_tac displays a warning if the new subgoal has type variables;
  5955 
  5956 * removed old README and Makefiles;
  5957 
  5958 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5959 
  5960 * removed obsolete init_pps and init_database;
  5961 
  5962 * deleted the obsolete tactical STATE, which was declared by
  5963     fun STATE tacfun st = tacfun st st;
  5964 
  5965 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5966 (which abbreviates $HOME);
  5967 
  5968 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5969 use isatool fixseq to adapt your ML programs (this works for fully
  5970 qualified references to the Sequence structure only!);
  5971 
  5972 * use_thy no longer requires writable current directory; it always
  5973 reloads .ML *and* .thy file, if either one is out of date;
  5974 
  5975 
  5976 *** Classical Reasoner ***
  5977 
  5978 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5979 tactics that use classical reasoning to simplify a subgoal without
  5980 splitting it into several subgoals;
  5981 
  5982 * Safe_tac: like safe_tac but uses the default claset;
  5983 
  5984 
  5985 *** Simplifier ***
  5986 
  5987 * added simplification meta rules:
  5988     (asm_)(full_)simplify: simpset -> thm -> thm;
  5989 
  5990 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5991 logics (again);
  5992 
  5993 * added prems argument to simplification procedures;
  5994 
  5995 * HOL, FOL, ZF: added infix function `addsplits':
  5996   instead of `<simpset> setloop (split_tac <thms>)'
  5997   you can simply write `<simpset> addsplits <thms>'
  5998 
  5999 
  6000 *** Syntax ***
  6001 
  6002 * TYPE('a) syntax for type reflection terms;
  6003 
  6004 * no longer handles consts with name "" -- declare as 'syntax' instead;
  6005 
  6006 * pretty printer: changed order of mixfix annotation preference (again!);
  6007 
  6008 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  6009 
  6010 
  6011 *** HOL ***
  6012 
  6013 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6014   with `addloop' of the simplifier to faciliate case splitting in premises.
  6015 
  6016 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  6017 
  6018 * HOL/Auth: new protocol proofs including some for the Internet
  6019   protocol TLS;
  6020 
  6021 * HOL/Map: new theory of `maps' a la VDM;
  6022 
  6023 * HOL/simplifier: simplification procedures nat_cancel_sums for
  6024 cancelling out common nat summands from =, <, <= (in)equalities, or
  6025 differences; simplification procedures nat_cancel_factor for
  6026 cancelling common factor from =, <, <= (in)equalities over natural
  6027 sums; nat_cancel contains both kinds of procedures, it is installed by
  6028 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  6029 
  6030 * HOL/simplifier: terms of the form
  6031   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  6032   are rewritten to
  6033   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  6034   and those of the form
  6035   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  6036   are rewritten to
  6037   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  6038 
  6039 * HOL/datatype
  6040   Each datatype `t' now comes with a theorem `split_t_case' of the form
  6041 
  6042   P(t_case f1 ... fn x) =
  6043      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  6044         ...
  6045        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  6046      )
  6047 
  6048   and a theorem `split_t_case_asm' of the form
  6049 
  6050   P(t_case f1 ... fn x) =
  6051     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  6052         ...
  6053        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  6054      )
  6055   which can be added to a simpset via `addsplits'. The existing theorems
  6056   expand_list_case and expand_option_case have been renamed to
  6057   split_list_case and split_option_case.
  6058 
  6059 * HOL/Arithmetic:
  6060   - `pred n' is automatically converted to `n-1'.
  6061     Users are strongly encouraged not to use `pred' any longer,
  6062     because it will disappear altogether at some point.
  6063   - Users are strongly encouraged to write "0 < n" rather than
  6064     "n ~= 0". Theorems and proof tools have been modified towards this
  6065     `standard'.
  6066 
  6067 * HOL/Lists:
  6068   the function "set_of_list" has been renamed "set" (and its theorems too);
  6069   the function "nth" now takes its arguments in the reverse order and
  6070   has acquired the infix notation "!" as in "xs!n".
  6071 
  6072 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  6073 
  6074 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  6075   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  6076 
  6077 * HOL/record: extensible records with schematic structural subtyping
  6078 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  6079 still lacks various theorems and concrete record syntax;
  6080 
  6081 
  6082 *** HOLCF ***
  6083 
  6084 * removed "axioms" and "generated by" sections;
  6085 
  6086 * replaced "ops" section by extended "consts" section, which is capable of
  6087   handling the continuous function space "->" directly;
  6088 
  6089 * domain package:
  6090   . proves theorems immediately and stores them in the theory,
  6091   . creates hierachical name space,
  6092   . now uses normal mixfix annotations (instead of cinfix...),
  6093   . minor changes to some names and values (for consistency),
  6094   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  6095   . separator between mutual domain defs: changed "," to "and",
  6096   . improved handling of sort constraints;  now they have to
  6097     appear on the left-hand side of the equations only;
  6098 
  6099 * fixed LAM <x,y,zs>.b syntax;
  6100 
  6101 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  6102 adm (%x. P (t x)), where P is chainfinite and t continuous;
  6103 
  6104 
  6105 *** FOL and ZF ***
  6106 
  6107 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6108   with `addloop' of the simplifier to faciliate case splitting in premises.
  6109 
  6110 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6111 in HOL, they strip ALL and --> from proved theorems;
  6112 
  6113 
  6114 
  6115 New in Isabelle94-8 (May 1997)
  6116 ------------------------------
  6117 
  6118 *** General Changes ***
  6119 
  6120 * new utilities to build / run / maintain Isabelle etc. (in parts
  6121 still somewhat experimental); old Makefiles etc. still functional;
  6122 
  6123 * new 'Isabelle System Manual';
  6124 
  6125 * INSTALL text, together with ./configure and ./build scripts;
  6126 
  6127 * reimplemented type inference for greater efficiency, better error
  6128 messages and clean internal interface;
  6129 
  6130 * prlim command for dealing with lots of subgoals (an easier way of
  6131 setting goals_limit);
  6132 
  6133 
  6134 *** Syntax ***
  6135 
  6136 * supports alternative (named) syntax tables (parser and pretty
  6137 printer); internal interface is provided by add_modesyntax(_i);
  6138 
  6139 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6140 be used in conjunction with the Isabelle symbol font; uses the
  6141 "symbols" syntax table;
  6142 
  6143 * added token_translation interface (may translate name tokens in
  6144 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6145 the current print_mode); IMPORTANT: user print translation functions
  6146 are responsible for marking newly introduced bounds
  6147 (Syntax.mark_boundT);
  6148 
  6149 * token translations for modes "xterm" and "xterm_color" that display
  6150 names in bold, underline etc. or colors (which requires a color
  6151 version of xterm);
  6152 
  6153 * infixes may now be declared with names independent of their syntax;
  6154 
  6155 * added typed_print_translation (like print_translation, but may
  6156 access type of constant);
  6157 
  6158 
  6159 *** Classical Reasoner ***
  6160 
  6161 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6162 some limitations.  Blast_tac...
  6163   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6164   + ignores elimination rules that don't have the correct format
  6165         (the conclusion MUST be a formula variable)
  6166   + ignores types, which can make HOL proofs fail
  6167   + rules must not require higher-order unification, e.g. apply_type in ZF
  6168     [message "Function Var's argument not a bound variable" relates to this]
  6169   + its proof strategy is more general but can actually be slower
  6170 
  6171 * substitution with equality assumptions no longer permutes other
  6172 assumptions;
  6173 
  6174 * minor changes in semantics of addafter (now called addaltern); renamed
  6175 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6176 (and access functions for it);
  6177 
  6178 * improved combination of classical reasoner and simplifier:
  6179   + functions for handling clasimpsets
  6180   + improvement of addss: now the simplifier is called _after_ the
  6181     safe steps.
  6182   + safe variant of addss called addSss: uses safe simplifications
  6183     _during_ the safe steps. It is more complete as it allows multiple
  6184     instantiations of unknowns (e.g. with slow_tac).
  6185 
  6186 *** Simplifier ***
  6187 
  6188 * added interface for simplification procedures (functions that
  6189 produce *proven* rewrite rules on the fly, depending on current
  6190 redex);
  6191 
  6192 * ordering on terms as parameter (used for ordered rewriting);
  6193 
  6194 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6195 
  6196 * the solver is now split into a safe and an unsafe part.
  6197 This should be invisible for the normal user, except that the
  6198 functions setsolver and addsolver have been renamed to setSolver and
  6199 addSolver; added safe_asm_full_simp_tac;
  6200 
  6201 
  6202 *** HOL ***
  6203 
  6204 * a generic induction tactic `induct_tac' which works for all datatypes and
  6205 also for type `nat';
  6206 
  6207 * a generic case distinction tactic `exhaust_tac' which works for all
  6208 datatypes and also for type `nat';
  6209 
  6210 * each datatype comes with a function `size';
  6211 
  6212 * patterns in case expressions allow tuple patterns as arguments to
  6213 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6214 
  6215 * primrec now also works with type nat;
  6216 
  6217 * recdef: a new declaration form, allows general recursive functions to be
  6218 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6219 
  6220 * the constant for negation has been renamed from "not" to "Not" to
  6221 harmonize with FOL, ZF, LK, etc.;
  6222 
  6223 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6224 infinite lists;
  6225 
  6226 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6227 
  6228 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6229 problems in commutative rings, using axiomatic type classes for + and *;
  6230 
  6231 * more examples in HOL/MiniML and HOL/Auth;
  6232 
  6233 * more default rewrite rules for quantifiers, union/intersection;
  6234 
  6235 * a new constant `arbitrary == @x.False';
  6236 
  6237 * HOLCF/IOA replaces old HOL/IOA;
  6238 
  6239 * HOLCF changes: derived all rules and arities
  6240   + axiomatic type classes instead of classes
  6241   + typedef instead of faking type definitions
  6242   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6243   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6244   + eliminated the types void, one, tr
  6245   + use unit lift and bool lift (with translations) instead of one and tr
  6246   + eliminated blift from Lift3.thy (use Def instead of blift)
  6247   all eliminated rules are derived as theorems --> no visible changes ;
  6248 
  6249 
  6250 *** ZF ***
  6251 
  6252 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6253 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6254 as ZF_cs addSIs [equalityI];
  6255 
  6256