NEWS
author hoelzl
Mon Jun 29 23:29:11 2009 +0200 (2009-06-29)
changeset 31863 e391eee8bf14
parent 31814 7c122634da81
child 31884 6129dea3d8a9
permissions -rw-r--r--
Implemented taylor series expansion for approximation
     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 * Class semiring_div requires superclass no_zero_divisors and proof of
    22 div_mult_mult1; theorems div_mult_mult1, div_mult_mult2,
    23 div_mult_mult1_if, div_mult_mult1 and div_mult_mult2 have been
    24 generalized to class semiring_div, subsuming former theorems
    25 zdiv_zmult_zmult1, zdiv_zmult_zmult1_if, zdiv_zmult_zmult1 and
    26 zdiv_zmult_zmult2.  div_mult_mult1 is now [simp] by default.
    27 INCOMPATIBILITY.
    28 
    29 * Power operations on relations and functions are now one dedicate
    30 constant compow with infix syntax "^^".  Power operations on
    31 multiplicative monoids retains syntax "^" and is now defined generic
    32 in class power.  INCOMPATIBILITY.
    33 
    34 * ML antiquotation @{code_datatype} inserts definition of a datatype
    35 generated by the code generator; see Predicate.thy for an example.
    36 
    37 * New method "linarith" invokes existing linear arithmetic decision
    38 procedure only.
    39 
    40 * Implementation of quickcheck using generic code generator; default generators
    41 are provided for all suitable HOL types, records and datatypes.
    42 
    43 * Constants Set.Pow and Set.image now with authentic syntax; object-logic definitions
    44 Set.Pow_def and Set.image_def.  INCOMPATIBILITY.
    45 
    46 * Renamed theorems:
    47 Suc_eq_add_numeral_1 -> Suc_eq_plus1
    48 Suc_eq_add_numeral_1_left -> Suc_eq_plus1_left
    49 Suc_plus1 -> Suc_eq_plus1
    50 
    51 * New sledgehammer option "Full Types" in Proof General settings menu.
    52 Causes full type information to be output to the ATPs. This slows ATPs down
    53 considerably but eliminates a source of unsound "proofs" that fail later.
    54 
    55 * Discontinued ancient tradition to suffix certain ML module names with "_package", e.g.:
    56 
    57     DatatypePackage ~> Datatype
    58     InductivePackage ~> Inductive
    59 
    60     etc.
    61 
    62 INCOMPATIBILITY.
    63 
    64 * NewNumberTheory: Jeremy Avigad's new version of part of NumberTheory.
    65 If possible, use NewNumberTheory, not NumberTheory.
    66 
    67 * Simplified interfaces of datatype module.  INCOMPATIBILITY.
    68 
    69 * Abbreviation "arbitrary" of "undefined" has disappeared; use "undefined" directly.
    70 INCOMPATIBILITY.
    71 
    72 * New evaluator "approximate" approximates an real valued term using the same method as the
    73 approximation method. 
    74 
    75 * "approximate" supports now arithmetic expressions as boundaries of intervals and implements
    76 interval splitting and taylor series expansion.
    77 
    78 
    79 *** ML ***
    80 
    81 * Eliminated old Attrib.add_attributes, Method.add_methods and related
    82 cominators for "args".  INCOMPATIBILITY, need to use simplified
    83 Attrib/Method.setup introduced in Isabelle2009.
    84 
    85 
    86 *** System ***
    87 
    88 * Discontinued support for Poly/ML 4.x versions.
    89 
    90 * Removed "compress" option from isabelle-process and isabelle usedir;
    91 this is always enabled.
    92 
    93 
    94 
    95 New in Isabelle2009 (April 2009)
    96 --------------------------------
    97 
    98 *** General ***
    99 
   100 * Simplified main Isabelle executables, with less surprises on
   101 case-insensitive file-systems (such as Mac OS).
   102 
   103   - The main Isabelle tool wrapper is now called "isabelle" instead of
   104     "isatool."
   105 
   106   - The former "isabelle" alias for "isabelle-process" has been
   107     removed (should rarely occur to regular users).
   108 
   109   - The former "isabelle-interface" and its alias "Isabelle" have been
   110     removed (interfaces are now regular Isabelle tools).
   111 
   112 Within scripts and make files, the Isabelle environment variables
   113 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
   114 respectively.  (The latter are still available as legacy feature.)
   115 
   116 The old isabelle-interface wrapper could react in confusing ways if
   117 the interface was uninstalled or changed otherwise.  Individual
   118 interface tool configuration is now more explicit, see also the
   119 Isabelle system manual.  In particular, Proof General is now available
   120 via "isabelle emacs".
   121 
   122 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
   123 purge installed copies of Isabelle executables and re-run "isabelle
   124 install -p ...", or use symlinks.
   125 
   126 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
   127 old ~/isabelle, which was slightly non-standard and apt to cause
   128 surprises on case-insensitive file-systems (such as Mac OS).
   129 
   130 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
   131 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
   132 care is required when using older releases of Isabelle.  Note that
   133 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
   134 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
   135 
   136 * Proofs of fully specified statements are run in parallel on
   137 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
   138 a regular 4-core machine, if the initial heap space is made reasonably
   139 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
   140 
   141 * The main reference manuals ("isar-ref", "implementation", and
   142 "system") have been updated and extended.  Formally checked references
   143 as hyperlinks are now available uniformly.
   144 
   145 
   146 *** Pure ***
   147 
   148 * Complete re-implementation of locales.  INCOMPATIBILITY in several
   149 respects.  The most important changes are listed below.  See the
   150 Tutorial on Locales ("locales" manual) for details.
   151 
   152 - In locale expressions, instantiation replaces renaming.  Parameters
   153 must be declared in a for clause.  To aid compatibility with previous
   154 parameter inheritance, in locale declarations, parameters that are not
   155 'touched' (instantiation position "_" or omitted) are implicitly added
   156 with their syntax at the beginning of the for clause.
   157 
   158 - Syntax from abbreviations and definitions in locales is available in
   159 locale expressions and context elements.  The latter is particularly
   160 useful in locale declarations.
   161 
   162 - More flexible mechanisms to qualify names generated by locale
   163 expressions.  Qualifiers (prefixes) may be specified in locale
   164 expressions, and can be marked as mandatory (syntax: "name!:") or
   165 optional (syntax "name?:").  The default depends for plain "name:"
   166 depends on the situation where a locale expression is used: in
   167 commands 'locale' and 'sublocale' prefixes are optional, in
   168 'interpretation' and 'interpret' prefixes are mandatory.  The old
   169 implicit qualifiers derived from the parameter names of a locale are
   170 no longer generated.
   171 
   172 - Command "sublocale l < e" replaces "interpretation l < e".  The
   173 instantiation clause in "interpretation" and "interpret" (square
   174 brackets) is no longer available.  Use locale expressions.
   175 
   176 - When converting proof scripts, mandatory qualifiers in
   177 'interpretation' and 'interpret' should be retained by default, even
   178 if this is an INCOMPATIBILITY compared to former behavior.  In the
   179 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   180 in locale expressions range over a single locale instance only.
   181 
   182 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   183 In existing theorem specifications replace the includes element by the
   184 respective context elements of the included locale, omitting those
   185 that are already present in the theorem specification.  Multiple
   186 assume elements of a locale should be replaced by a single one
   187 involving the locale predicate.  In the proof body, declarations (most
   188 notably theorems) may be regained by interpreting the respective
   189 locales in the proof context as required (command "interpret").
   190 
   191 If using "includes" in replacement of a target solely because the
   192 parameter types in the theorem are not as general as in the target,
   193 consider declaring a new locale with additional type constraints on
   194 the parameters (context element "constrains").
   195 
   196 - Discontinued "locale (open)".  INCOMPATIBILITY.
   197 
   198 - Locale interpretation commands no longer attempt to simplify goal.
   199 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   200 methods intro_locales and unfold_locales to clarify.
   201 
   202 - Locale interpretation commands no longer accept interpretation
   203 attributes.  INCOMPATIBILITY.
   204 
   205 * Class declaration: so-called "base sort" must not be given in import
   206 list any longer, but is inferred from the specification.  Particularly
   207 in HOL, write
   208 
   209     class foo = ...
   210 
   211 instead of
   212 
   213     class foo = type + ...
   214 
   215 * Class target: global versions of theorems stemming do not carry a
   216 parameter prefix any longer.  INCOMPATIBILITY.
   217 
   218 * Class 'instance' command no longer accepts attached definitions.
   219 INCOMPATIBILITY, use proper 'instantiation' target instead.
   220 
   221 * Recovered hiding of consts, which was accidentally broken in
   222 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   223 makes c inaccessible; consider using ``hide (open) const c'' instead.
   224 
   225 * Slightly more coherent Pure syntax, with updated documentation in
   226 isar-ref manual.  Removed locales meta_term_syntax and
   227 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   228 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   229 directly in regular applications.
   230 
   231 * There is a new syntactic category "float_const" for signed decimal
   232 fractions (e.g. 123.45 or -123.45).
   233 
   234 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   235 interface with 'setup' command instead.
   236 
   237 * Command 'local_setup' is similar to 'setup', but operates on a local
   238 theory context.
   239 
   240 * The 'axiomatization' command now only works within a global theory
   241 context.  INCOMPATIBILITY.
   242 
   243 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   244 hypotheses.  Sorts required in the course of reasoning need to be
   245 covered by the constraints in the initial statement, completed by the
   246 type instance information of the background theory.  Non-trivial sort
   247 hypotheses, which rarely occur in practice, may be specified via
   248 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   249 
   250   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   251 
   252 The result contains an implicit sort hypotheses as before --
   253 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   254 normalization.
   255 
   256 * Generalized Isar history, with support for linear undo, direct state
   257 addressing etc.
   258 
   259 * Changed defaults for unify configuration options:
   260 
   261   unify_trace_bound = 50 (formerly 25)
   262   unify_search_bound = 60 (formerly 30)
   263 
   264 * Different bookkeeping for code equations (INCOMPATIBILITY):
   265 
   266   a) On theory merge, the last set of code equations for a particular
   267      constant is taken (in accordance with the policy applied by other
   268      parts of the code generator framework).
   269 
   270   b) Code equations stemming from explicit declarations (e.g. code
   271      attribute) gain priority over default code equations stemming
   272      from definition, primrec, fun etc.
   273 
   274 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   275 
   276 * Unified theorem tables for both code generators.  Thus [code
   277 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   278 
   279 * Command 'find_consts' searches for constants based on type and name
   280 patterns, e.g.
   281 
   282     find_consts "_ => bool"
   283 
   284 By default, matching is against subtypes, but it may be restricted to
   285 the whole type.  Searching by name is possible.  Multiple queries are
   286 conjunctive and queries may be negated by prefixing them with a
   287 hyphen:
   288 
   289     find_consts strict: "_ => bool" name: "Int" -"int => int"
   290 
   291 * New 'find_theorems' criterion "solves" matches theorems that
   292 directly solve the current goal (modulo higher-order unification).
   293 
   294 * Auto solve feature for main theorem statements: whenever a new goal
   295 is stated, "find_theorems solves" is called; any theorems that could
   296 solve the lemma directly are listed as part of the goal state.
   297 Cf. associated options in Proof General Isabelle settings menu,
   298 enabled by default, with reasonable timeout for pathological cases of
   299 higher-order unification.
   300 
   301 
   302 *** Document preparation ***
   303 
   304 * Antiquotation @{lemma} now imitates a regular terminal proof,
   305 demanding keyword 'by' and supporting the full method expression
   306 syntax just like the Isar command 'by'.
   307 
   308 
   309 *** HOL ***
   310 
   311 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   312 points Main and Complex_Main remain as before.
   313 
   314 * Logic image HOL-Plain provides a minimal HOL with the most important
   315 tools available (inductive, datatype, primrec, ...).  This facilitates
   316 experimentation and tool development.  Note that user applications
   317 (and library theories) should never refer to anything below theory
   318 Main, as before.
   319 
   320 * Logic image HOL-Main stops at theory Main, and thus facilitates
   321 experimentation due to shorter build times.
   322 
   323 * Logic image HOL-NSA contains theories of nonstandard analysis which
   324 were previously part of former HOL-Complex.  Entry point Hyperreal
   325 remains valid, but theories formerly using Complex_Main should now use
   326 new entry point Hypercomplex.
   327 
   328 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   329 Posix processes.  Avoids potentially expensive forking of the ML
   330 process.  New thread-based implementation also works on non-Unix
   331 platforms (Cygwin).  Provers are no longer hardwired, but defined
   332 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   333 commands are covered in the isar-ref manual.
   334 
   335 * Wrapper scripts for remote SystemOnTPTP service allows to use
   336 sledgehammer without local ATP installation (Vampire etc.). Other
   337 provers may be included via suitable ML wrappers, see also
   338 src/HOL/ATP_Linkup.thy.
   339 
   340 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   341 menu.
   342 
   343 * The metis method no longer fails because the theorem is too trivial
   344 (contains the empty clause).
   345 
   346 * The metis method now fails in the usual manner, rather than raising
   347 an exception, if it determines that it cannot prove the theorem.
   348 
   349 * Method "coherent" implements a prover for coherent logic (see also
   350 src/Tools/coherent.ML).
   351 
   352 * Constants "undefined" and "default" replace "arbitrary".  Usually
   353 "undefined" is the right choice to replace "arbitrary", though
   354 logically there is no difference.  INCOMPATIBILITY.
   355 
   356 * Command "value" now integrates different evaluation mechanisms.  The
   357 result of the first successful evaluation mechanism is printed.  In
   358 square brackets a particular named evaluation mechanisms may be
   359 specified (currently, [SML], [code] or [nbe]).  See further
   360 src/HOL/ex/Eval_Examples.thy.
   361 
   362 * Normalization by evaluation now allows non-leftlinear equations.
   363 Declare with attribute [code nbe].
   364 
   365 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   366 as the structured Isar versions "cases" and "induct", cf. the
   367 corresponding "cases" and "induct" attributes.  Mutual induction rules
   368 are now presented as a list of individual projections
   369 (e.g. foo_bar.inducts for types foo and bar); the old format with
   370 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   371 rare situations a different rule is selected --- notably nested tuple
   372 elimination instead of former prod.exhaust: use explicit (case_tac t
   373 rule: prod.exhaust) here.
   374 
   375 * Attributes "cases", "induct", "coinduct" support "del" option.
   376 
   377 * Removed fact "case_split_thm", which duplicates "case_split".
   378 
   379 * The option datatype has been moved to a new theory Option.  Renamed
   380 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   381 
   382 * New predicate "strict_mono" classifies strict functions on partial
   383 orders.  With strict functions on linear orders, reasoning about
   384 (in)equalities is facilitated by theorems "strict_mono_eq",
   385 "strict_mono_less_eq" and "strict_mono_less".
   386 
   387 * Some set operations are now proper qualified constants with
   388 authentic syntax.  INCOMPATIBILITY:
   389 
   390     op Int ~>   Set.Int
   391     op Un ~>    Set.Un
   392     INTER ~>    Set.INTER
   393     UNION ~>    Set.UNION
   394     Inter ~>    Set.Inter
   395     Union ~>    Set.Union
   396     {} ~>       Set.empty
   397     UNIV ~>     Set.UNIV
   398 
   399 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   400 theory Set.
   401 
   402 * Auxiliary class "itself" has disappeared -- classes without any
   403 parameter are treated as expected by the 'class' command.
   404 
   405 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   406 
   407 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   408 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   409 
   410 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   411 method "approximation".  It proves formulas on real values by using
   412 interval arithmetic.  In the formulas are also the transcendental
   413 functions sin, cos, tan, atan, ln, exp and the constant pi are
   414 allowed. For examples see
   415 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   416 
   417 * Theory "Reflection" now resides in HOL/Library.
   418 
   419 * Entry point to Word library now simply named "Word".
   420 INCOMPATIBILITY.
   421 
   422 * Made source layout more coherent with logical distribution
   423 structure:
   424 
   425     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   426     src/HOL/Library/Code_Message.thy ~> src/HOL/
   427     src/HOL/Library/GCD.thy ~> src/HOL/
   428     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   429     src/HOL/Library/Parity.thy ~> src/HOL/
   430     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   431     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   432     src/HOL/Real/Lubs.thy ~> src/HOL/
   433     src/HOL/Real/PReal.thy ~> src/HOL/
   434     src/HOL/Real/Rational.thy ~> src/HOL/
   435     src/HOL/Real/RComplete.thy ~> src/HOL/
   436     src/HOL/Real/RealDef.thy ~> src/HOL/
   437     src/HOL/Real/RealPow.thy ~> src/HOL/
   438     src/HOL/Real/Real.thy ~> src/HOL/
   439     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   440     src/HOL/Complex/Complex.thy ~> src/HOL/
   441     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   442     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   443     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   444     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   445     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   446     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   447     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   448     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   449     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   450     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   451     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   452     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   453     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   454     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   455     src/HOL/Real/Float ~> src/HOL/Library/
   456     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   457     src/HOL/Real/RealVector.thy ~> src/HOL/
   458 
   459     src/HOL/arith_data.ML ~> src/HOL/Tools
   460     src/HOL/hologic.ML ~> src/HOL/Tools
   461     src/HOL/simpdata.ML ~> src/HOL/Tools
   462     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   463     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   464     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   465     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   466     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   467     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   468     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   469 
   470     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   471     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   472     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   473     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   474     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   475     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   476 
   477 * If methods "eval" and "evaluation" encounter a structured proof
   478 state with !!/==>, only the conclusion is evaluated to True (if
   479 possible), avoiding strange error messages.
   480 
   481 * Method "sizechange" automates termination proofs using (a
   482 modification of) the size-change principle.  Requires SAT solver.  See
   483 src/HOL/ex/Termination.thy for examples.
   484 
   485 * Simplifier: simproc for let expressions now unfolds if bound
   486 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   487 
   488 * Method "arith": Linear arithmetic now ignores all inequalities when
   489 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   490 
   491 * New attribute "arith" for facts that should always be used
   492 automatically by arithmetic. It is intended to be used locally in
   493 proofs, e.g.
   494 
   495   assumes [arith]: "x > 0"
   496 
   497 Global usage is discouraged because of possible performance impact.
   498 
   499 * New classes "top" and "bot" with corresponding operations "top" and
   500 "bot" in theory Orderings; instantiation of class "complete_lattice"
   501 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   502 
   503 * Changed definition lemma "less_fun_def" in order to provide an
   504 instance for preorders on functions; use lemma "less_le" instead.
   505 INCOMPATIBILITY.
   506 
   507 * Theory Orderings: class "wellorder" moved here, with explicit
   508 induction rule "less_induct" as assumption.  For instantiation of
   509 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   510 INCOMPATIBILITY.
   511 
   512 * Theory Orderings: added class "preorder" as superclass of "order".
   513 INCOMPATIBILITY: Instantiation proofs for order, linorder
   514 etc. slightly changed.  Some theorems named order_class.* now named
   515 preorder_class.*.
   516 
   517 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   518 "diag" to "Id_on".
   519 
   520 * Theory Finite_Set: added a new fold combinator of type
   521 
   522   ('a => 'b => 'b) => 'b => 'a set => 'b
   523 
   524 Occasionally this is more convenient than the old fold combinator
   525 which is now defined in terms of the new one and renamed to
   526 fold_image.
   527 
   528 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   529 and "ring_simps" have been replaced by "algebra_simps" (which can be
   530 extended with further lemmas!).  At the moment both still exist but
   531 the former will disappear at some point.
   532 
   533 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   534 class recpower.  Type-specific simp rules for various recpower types
   535 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   536 
   537 rat_power_0    -> power_0
   538 rat_power_Suc  -> power_Suc
   539 realpow_0      -> power_0
   540 realpow_Suc    -> power_Suc
   541 complexpow_0   -> power_0
   542 complexpow_Suc -> power_Suc
   543 power_poly_0   -> power_0
   544 power_poly_Suc -> power_Suc
   545 
   546 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   547 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   548 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   549 of lemmas from Divides has been generalized from nat to class
   550 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   551 renames resulting from duplicate elimination:
   552 
   553     dvd_def_mod ~>          dvd_eq_mod_eq_0
   554     zero_dvd_iff ~>         dvd_0_left_iff
   555     dvd_0 ~>                dvd_0_right
   556     DIVISION_BY_ZERO_DIV ~> div_by_0
   557     DIVISION_BY_ZERO_MOD ~> mod_by_0
   558     mult_div ~>             div_mult_self2_is_id
   559     mult_mod ~>             mod_mult_self2_is_0
   560 
   561 * Theory IntDiv: removed many lemmas that are instances of class-based
   562 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   563 rename old lemmas as follows:
   564 
   565 dvd_diff               -> nat_dvd_diff
   566 dvd_zminus_iff         -> dvd_minus_iff
   567 mod_add1_eq            -> mod_add_eq
   568 mod_mult1_eq           -> mod_mult_right_eq
   569 mod_mult1_eq'          -> mod_mult_left_eq
   570 mod_mult_distrib_mod   -> mod_mult_eq
   571 nat_mod_add_left_eq    -> mod_add_left_eq
   572 nat_mod_add_right_eq   -> mod_add_right_eq
   573 nat_mod_div_trivial    -> mod_div_trivial
   574 nat_mod_mod_trivial    -> mod_mod_trivial
   575 zdiv_zadd_self1        -> div_add_self1
   576 zdiv_zadd_self2        -> div_add_self2
   577 zdiv_zmult_self1       -> div_mult_self2_is_id
   578 zdiv_zmult_self2       -> div_mult_self1_is_id
   579 zdvd_triv_left         -> dvd_triv_left
   580 zdvd_triv_right        -> dvd_triv_right
   581 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   582 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   583 zmod_zadd_left_eq      -> mod_add_left_eq
   584 zmod_zadd_right_eq     -> mod_add_right_eq
   585 zmod_zadd_self1        -> mod_add_self1
   586 zmod_zadd_self2        -> mod_add_self2
   587 zmod_zadd1_eq          -> mod_add_eq
   588 zmod_zdiff1_eq         -> mod_diff_eq
   589 zmod_zdvd_zmod         -> mod_mod_cancel
   590 zmod_zmod_cancel       -> mod_mod_cancel
   591 zmod_zmult_self1       -> mod_mult_self2_is_0
   592 zmod_zmult_self2       -> mod_mult_self1_is_0
   593 zmod_1                 -> mod_by_1
   594 zdiv_1                 -> div_by_1
   595 zdvd_abs1              -> abs_dvd_iff
   596 zdvd_abs2              -> dvd_abs_iff
   597 zdvd_refl              -> dvd_refl
   598 zdvd_trans             -> dvd_trans
   599 zdvd_zadd              -> dvd_add
   600 zdvd_zdiff             -> dvd_diff
   601 zdvd_zminus_iff        -> dvd_minus_iff
   602 zdvd_zminus2_iff       -> minus_dvd_iff
   603 zdvd_zmultD            -> dvd_mult_right
   604 zdvd_zmultD2           -> dvd_mult_left
   605 zdvd_zmult_mono        -> mult_dvd_mono
   606 zdvd_0_right           -> dvd_0_right
   607 zdvd_0_left            -> dvd_0_left_iff
   608 zdvd_1_left            -> one_dvd
   609 zminus_dvd_iff         -> minus_dvd_iff
   610 
   611 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   612 
   613 * The real numbers offer decimal input syntax: 12.34 is translated
   614 into 1234/10^2. This translation is not reversed upon output.
   615 
   616 * Theory Library/Polynomial defines an abstract type 'a poly of
   617 univariate polynomials with coefficients of type 'a.  In addition to
   618 the standard ring operations, it also supports div and mod.  Code
   619 generation is also supported, using list-style constructors.
   620 
   621 * Theory Library/Inner_Product defines a class of real_inner for real
   622 inner product spaces, with an overloaded operation inner :: 'a => 'a
   623 => real.  Class real_inner is a subclass of real_normed_vector from
   624 theory RealVector.
   625 
   626 * Theory Library/Product_Vector provides instances for the product
   627 type 'a * 'b of several classes from RealVector and Inner_Product.
   628 Definitions of addition, subtraction, scalar multiplication, norms,
   629 and inner products are included.
   630 
   631 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   632 addition to the field operations, numerals and case syntax are also
   633 supported.
   634 
   635 * Theory Library/Diagonalize provides constructive version of Cantor's
   636 first diagonalization argument.
   637 
   638 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   639 zlcm (for int); carried together from various gcd/lcm developements in
   640 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   641 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   642 may recover tupled syntax as follows:
   643 
   644     hide (open) const gcd
   645     abbreviation gcd where
   646       "gcd == (%(a, b). GCD.gcd a b)"
   647     notation (output)
   648       GCD.gcd ("gcd '(_, _')")
   649 
   650 The same works for lcm, zgcd, zlcm.
   651 
   652 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   653 instantiations for algebraic structures.  Removed some duplicate
   654 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   655 
   656 * ML antiquotation @{code} takes a constant as argument and generates
   657 corresponding code in background and inserts name of the corresponding
   658 resulting ML value/function/datatype constructor binding in place.
   659 All occurrences of @{code} with a single ML block are generated
   660 simultaneously.  Provides a generic and safe interface for
   661 instrumentalizing code generation.  See
   662 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   663 In future you ought to refrain from ad-hoc compiling generated SML
   664 code on the ML toplevel.  Note that (for technical reasons) @{code}
   665 cannot refer to constants for which user-defined serializations are
   666 set.  Refer to the corresponding ML counterpart directly in that
   667 cases.
   668 
   669 * Command 'rep_datatype': instead of theorem names the command now
   670 takes a list of terms denoting the constructors of the type to be
   671 represented as datatype.  The characteristic theorems have to be
   672 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   673 have disappeared in favour of existing ones:
   674 
   675     unit_induct                 ~> unit.induct
   676     prod_induct                 ~> prod.induct
   677     sum_induct                  ~> sum.induct
   678     Suc_Suc_eq                  ~> nat.inject
   679     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   680 
   681 
   682 *** HOL-Algebra ***
   683 
   684 * New locales for orders and lattices where the equivalence relation
   685 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   686 locales use a record structure with field eq for the equivalence.
   687 
   688 * New theory of factorial domains.
   689 
   690 * Units_l_inv and Units_r_inv are now simp rules by default.
   691 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   692 and/or r_inv will now also require deletion of these lemmas.
   693 
   694 * Renamed the following theorems, INCOMPATIBILITY:
   695 
   696 UpperD ~> Upper_memD
   697 LowerD ~> Lower_memD
   698 least_carrier ~> least_closed
   699 greatest_carrier ~> greatest_closed
   700 greatest_Lower_above ~> greatest_Lower_below
   701 one_zero ~> carrier_one_zero
   702 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   703 
   704 
   705 *** HOL-Nominal ***
   706 
   707 * Nominal datatypes can now contain type-variables.
   708 
   709 * Commands 'nominal_inductive' and 'equivariance' work with local
   710 theory targets.
   711 
   712 * Nominal primrec can now works with local theory targets and its
   713 specification syntax now conforms to the general format as seen in
   714 'inductive' etc.
   715 
   716 * Method "perm_simp" honours the standard simplifier attributes
   717 (no_asm), (no_asm_use) etc.
   718 
   719 * The new predicate #* is defined like freshness, except that on the
   720 left hand side can be a set or list of atoms.
   721 
   722 * Experimental command 'nominal_inductive2' derives strong induction
   723 principles for inductive definitions.  In contrast to
   724 'nominal_inductive', which can only deal with a fixed number of
   725 binders, it can deal with arbitrary expressions standing for sets of
   726 atoms to be avoided.  The only inductive definition we have at the
   727 moment that needs this generalisation is the typing rule for Lets in
   728 the algorithm W:
   729 
   730  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   731  -----------------------------------------------------------------
   732          Gamma |- Let x be t1 in t2 : T2
   733 
   734 In this rule one wants to avoid all the binders that are introduced by
   735 "close Gamma T1".  We are looking for other examples where this
   736 feature might be useful.  Please let us know.
   737 
   738 
   739 *** HOLCF ***
   740 
   741 * Reimplemented the simplification procedure for proving continuity
   742 subgoals.  The new simproc is extensible; users can declare additional
   743 continuity introduction rules with the attribute [cont2cont].
   744 
   745 * The continuity simproc now uses a different introduction rule for
   746 solving continuity subgoals on terms with lambda abstractions.  In
   747 some rare cases the new simproc may fail to solve subgoals that the
   748 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   749 Potential INCOMPATIBILITY.
   750 
   751 * Command 'fixrec': specification syntax now conforms to the general
   752 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   753 examples.  INCOMPATIBILITY.
   754 
   755 
   756 *** ZF ***
   757 
   758 * Proof of Zorn's Lemma for partial orders.
   759 
   760 
   761 *** ML ***
   762 
   763 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   764 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   765 depends on multithreading, so timouts will not work before Poly/ML
   766 5.2.1!
   767 
   768 * High-level support for concurrent ML programming, see
   769 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   770 particularly convenient to organize independent functional
   771 computations.  The concept of "synchronized variables" provides a
   772 higher-order interface for components with shared state, avoiding the
   773 delicate details of mutexes and condition variables.  (Requires
   774 Poly/ML 5.2.1 or later.)
   775 
   776 * ML bindings produced via Isar commands are stored within the Isar
   777 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   778 become thread-safe and work with undo as expected (concerning
   779 top-level bindings, not side-effects on global references).
   780 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   781 compiler at runtime; really global bindings need to be given outside a
   782 theory.  (Requires Poly/ML 5.2 or later.)
   783 
   784 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   785 context.  Top-level ML bindings are stored within the proof context in
   786 a purely sequential fashion, disregarding the nested proof structure.
   787 ML bindings introduced by 'ML_prf' are discarded at the end of the
   788 proof.  (Requires Poly/ML 5.2 or later.)
   789 
   790 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   791 and Method.setup, as well as Isar commands 'attribute_setup' and
   792 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   793 existing code accordingly, or use plain 'setup' together with old
   794 Method.add_method.
   795 
   796 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   797 to 'a -> thm, while results are always tagged with an authentic oracle
   798 name.  The Isar command 'oracle' is now polymorphic, no argument type
   799 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   800 accordingly.  Note that extra performance may be gained by producing
   801 the cterm carefully, avoiding slow Thm.cterm_of.
   802 
   803 * Simplified interface for defining document antiquotations via
   804 ThyOutput.antiquotation, ThyOutput.output, and optionally
   805 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   806 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   807 examples.
   808 
   809 * More systematic treatment of long names, abstract name bindings, and
   810 name space operations.  Basic operations on qualified names have been
   811 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   812 Long_Name.append.  Old type bstring has been mostly replaced by
   813 abstract type binding (see structure Binding), which supports precise
   814 qualification by packages and local theory targets, as well as proper
   815 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   816 bstring values into Binding.name, or better pass through abstract
   817 bindings everywhere.  See further src/Pure/General/long_name.ML,
   818 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   819 
   820 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   821 LocalTheory.note etc.) now refer to the *full* internal name, not the
   822 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   823 
   824 * Disposed old type and term read functions (Sign.read_def_typ,
   825 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   826 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   827 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   828 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   829 resort for legacy applications.
   830 
   831 * Disposed old declarations, tactics, tactic combinators that refer to
   832 the simpset or claset of an implicit theory (such as Addsimps,
   833 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   834 embedded ML text, or local_simpset_of with a proper context passed as
   835 explicit runtime argument.
   836 
   837 * Rules and tactics that read instantiations (read_instantiate,
   838 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   839 context, which is required for parsing and type-checking.  Moreover,
   840 the variables are specified as plain indexnames, not string encodings
   841 thereof.  INCOMPATIBILITY.
   842 
   843 * Generic Toplevel.add_hook interface allows to analyze the result of
   844 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   845 for theorem dependency output of transactions resulting in a new
   846 theory state.
   847 
   848 * ML antiquotations: block-structured compilation context indicated by
   849 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   850 
   851   @{binding name}                         - basic name binding
   852   @{let ?pat = term}                      - term abbreviation (HO matching)
   853   @{note name = fact}                     - fact abbreviation
   854   @{thm fact}                             - singleton fact (with attributes)
   855   @{thms fact}                            - general fact (with attributes)
   856   @{lemma prop by method}                 - singleton goal
   857   @{lemma prop by meth1 meth2}            - singleton goal
   858   @{lemma prop1 ... propN by method}      - general goal
   859   @{lemma prop1 ... propN by meth1 meth2} - general goal
   860   @{lemma (open) ...}                     - open derivation
   861 
   862 
   863 *** System ***
   864 
   865 * The Isabelle "emacs" tool provides a specific interface to invoke
   866 Proof General / Emacs, with more explicit failure if that is not
   867 installed (the old isabelle-interface script silently falls back on
   868 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   869 installation location of the Proof General distribution.
   870 
   871 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   872 the Isabelle process into a JVM/Scala application.  See
   873 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   874 process wrapper has been discontinued.)
   875 
   876 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   877 
   878 * Various status messages (with exact source position information) are
   879 emitted, if proper markup print mode is enabled.  This allows
   880 user-interface components to provide detailed feedback on internal
   881 prover operations.
   882 
   883 
   884 
   885 New in Isabelle2008 (June 2008)
   886 -------------------------------
   887 
   888 *** General ***
   889 
   890 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   891 and updated, with formally checked references as hyperlinks.
   892 
   893 * Theory loader: use_thy (and similar operations) no longer set the
   894 implicit ML context, which was occasionally hard to predict and in
   895 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   896 provides a proper context already.
   897 
   898 * Theory loader: old-style ML proof scripts being *attached* to a thy
   899 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   900 'use' within a theory file will do the job.
   901 
   902 * Name space merge now observes canonical order, i.e. the second space
   903 is inserted into the first one, while existing entries in the first
   904 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   905 swap theory imports.
   906 
   907 * Syntax: symbol \<chi> is now considered a letter.  Potential
   908 INCOMPATIBILITY in identifier syntax etc.
   909 
   910 * Outer syntax: string tokens no longer admit escaped white space,
   911 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   912 white space without escapes.
   913 
   914 * Outer syntax: string tokens may contain arbitrary character codes
   915 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   916 "foo_bar".
   917 
   918 
   919 *** Pure ***
   920 
   921 * Context-dependent token translations.  Default setup reverts locally
   922 fixed variables, and adds hilite markup for undeclared frees.
   923 
   924 * Unused theorems can be found using the new command 'unused_thms'.
   925 There are three ways of invoking it:
   926 
   927 (1) unused_thms
   928      Only finds unused theorems in the current theory.
   929 
   930 (2) unused_thms thy_1 ... thy_n -
   931      Finds unused theorems in the current theory and all of its ancestors,
   932      excluding the theories thy_1 ... thy_n and all of their ancestors.
   933 
   934 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   935      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   936      their ancestors, excluding the theories thy_1 ... thy_n and all of
   937      their ancestors.
   938 
   939 In order to increase the readability of the list produced by
   940 unused_thms, theorems that have been created by a particular instance
   941 of a theory command such as 'inductive' or 'function' are considered
   942 to belong to the same "group", meaning that if at least one theorem in
   943 this group is used, the other theorems in the same group are no longer
   944 reported as unused.  Moreover, if all theorems in the group are
   945 unused, only one theorem in the group is displayed.
   946 
   947 Note that proof objects have to be switched on in order for
   948 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   949 usually the case when using Proof General with the default settings).
   950 
   951 * Authentic naming of facts disallows ad-hoc overwriting of previous
   952 theorems within the same name space.  INCOMPATIBILITY, need to remove
   953 duplicate fact bindings, or even accidental fact duplications.  Note
   954 that tools may maintain dynamically scoped facts systematically, using
   955 PureThy.add_thms_dynamic.
   956 
   957 * Command 'hide' now allows to hide from "fact" name space as well.
   958 
   959 * Eliminated destructive theorem database, simpset, claset, and
   960 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   961 update of theories within ML code.
   962 
   963 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   964 INCOMPATIBILITY, object-logics depending on former Pure require
   965 additional setup PureThy.old_appl_syntax_setup; object-logics
   966 depending on former CPure need to refer to Pure.
   967 
   968 * Commands 'use' and 'ML' are now purely functional, operating on
   969 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   970 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   971 INCOMPATIBILITY.
   972 
   973 * Command 'setup': discontinued implicit version with ML reference.
   974 
   975 * Instantiation target allows for simultaneous specification of class
   976 instance operations together with an instantiation proof.
   977 Type-checking phase allows to refer to class operations uniformly.
   978 See src/HOL/Complex/Complex.thy for an Isar example and
   979 src/HOL/Library/Eval.thy for an ML example.
   980 
   981 * Indexing of literal facts: be more serious about including only
   982 facts from the visible specification/proof context, but not the
   983 background context (locale etc.).  Affects `prop` notation and method
   984 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   985 situations.
   986 
   987 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   988 "(open)" option, which used to expose internal bound variables to the
   989 proof text.
   990 
   991 * Isar statements: removed obsolete case "rule_context".
   992 INCOMPATIBILITY, better use explicit fixes/assumes.
   993 
   994 * Locale proofs: default proof step now includes 'unfold_locales';
   995 hence 'proof' without argument may be used to unfold locale
   996 predicates.
   997 
   998 
   999 *** Document preparation ***
  1000 
  1001 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
  1002 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
  1003 obsolete thumbpdf setup (contemporary PDF viewers do this on the
  1004 spot); renamed link color from "darkblue" to "linkcolor" (default
  1005 value unchanged, can be redefined via \definecolor); no longer sets
  1006 "a4paper" option (unnecessary or even intrusive).
  1007 
  1008 * Antiquotation @{lemma A method} proves proposition A by the given
  1009 method (either a method name or a method name plus (optional) method
  1010 arguments in parentheses) and prints A just like @{prop A}.
  1011 
  1012 
  1013 *** HOL ***
  1014 
  1015 * New primrec package.  Specification syntax conforms in style to
  1016 definition/function/....  No separate induction rule is provided.  The
  1017 "primrec" command distinguishes old-style and new-style specifications
  1018 by syntax.  The former primrec package is now named OldPrimrecPackage.
  1019 When adjusting theories, beware: constants stemming from new-style
  1020 primrec specifications have authentic syntax.
  1021 
  1022 * Metis prover is now an order of magnitude faster, and also works
  1023 with multithreading.
  1024 
  1025 * Metis: the maximum number of clauses that can be produced from a
  1026 theorem is now given by the attribute max_clauses.  Theorems that
  1027 exceed this number are ignored, with a warning printed.
  1028 
  1029 * Sledgehammer no longer produces structured proofs by default. To
  1030 enable, declare [[sledgehammer_full = true]].  Attributes
  1031 reconstruction_modulus, reconstruction_sorts renamed
  1032 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
  1033 
  1034 * Method "induct_scheme" derives user-specified induction rules
  1035 from well-founded induction and completeness of patterns. This factors
  1036 out some operations that are done internally by the function package
  1037 and makes them available separately.  See
  1038 src/HOL/ex/Induction_Scheme.thy for examples.
  1039 
  1040 * More flexible generation of measure functions for termination
  1041 proofs: Measure functions can be declared by proving a rule of the
  1042 form "is_measure f" and giving it the [measure_function] attribute.
  1043 The "is_measure" predicate is logically meaningless (always true), and
  1044 just guides the heuristic.  To find suitable measure functions, the
  1045 termination prover sets up the goal "is_measure ?f" of the appropriate
  1046 type and generates all solutions by prolog-style backwards proof using
  1047 the declared rules.
  1048 
  1049 This setup also deals with rules like 
  1050 
  1051   "is_measure f ==> is_measure (list_size f)"
  1052 
  1053 which accommodates nested datatypes that recurse through lists.
  1054 Similar rules are predeclared for products and option types.
  1055 
  1056 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
  1057 
  1058   INCOMPATIBILITIES:
  1059 
  1060   - Definitions of overloaded constants on sets have to be replaced by
  1061     definitions on => and bool.
  1062 
  1063   - Some definitions of overloaded operators on sets can now be proved
  1064     using the definitions of the operators on => and bool.  Therefore,
  1065     the following theorems have been renamed:
  1066 
  1067       subset_def   -> subset_eq
  1068       psubset_def  -> psubset_eq
  1069       set_diff_def -> set_diff_eq
  1070       Compl_def    -> Compl_eq
  1071       Sup_set_def  -> Sup_set_eq
  1072       Inf_set_def  -> Inf_set_eq
  1073       sup_set_def  -> sup_set_eq
  1074       inf_set_def  -> inf_set_eq
  1075 
  1076   - Due to the incompleteness of the HO unification algorithm, some
  1077     rules such as subst may require manual instantiation, if some of
  1078     the unknowns in the rule is a set.
  1079 
  1080   - Higher order unification and forward proofs:
  1081     The proof pattern
  1082 
  1083       have "P (S::'a set)" <...>
  1084       then have "EX S. P S" ..
  1085 
  1086     no longer works (due to the incompleteness of the HO unification
  1087     algorithm) and must be replaced by the pattern
  1088 
  1089       have "EX S. P S"
  1090       proof
  1091         show "P S" <...>
  1092       qed
  1093 
  1094   - Calculational reasoning with subst (or similar rules):
  1095     The proof pattern
  1096 
  1097       have "P (S::'a set)" <...>
  1098       also have "S = T" <...>
  1099       finally have "P T" .
  1100 
  1101     no longer works (for similar reasons as the previous example) and
  1102     must be replaced by something like
  1103 
  1104       have "P (S::'a set)" <...>
  1105       moreover have "S = T" <...>
  1106       ultimately have "P T" by simp
  1107 
  1108   - Tactics or packages written in ML code:
  1109     Code performing pattern matching on types via
  1110 
  1111       Type ("set", [T]) => ...
  1112 
  1113     must be rewritten. Moreover, functions like strip_type or
  1114     binder_types no longer return the right value when applied to a
  1115     type of the form
  1116 
  1117       T1 => ... => Tn => U => bool
  1118 
  1119     rather than
  1120 
  1121       T1 => ... => Tn => U set
  1122 
  1123 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1124 Wellfounded_Relations to theory Wellfounded.
  1125 
  1126 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1127 
  1128 * Class finite no longer treats UNIV as class parameter.  Use class
  1129 enum from theory Library/Enum instead to achieve a similar effect.
  1130 INCOMPATIBILITY.
  1131 
  1132 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1133 and "Cons".  INCOMPATIBILITY.
  1134 
  1135 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1136 Potential INCOMPATIBILITY.
  1137 
  1138 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1139 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1140 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1141 
  1142 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1143 the same name in theory Orderings:
  1144 
  1145   less_trans
  1146   less_linear
  1147   le_imp_less_or_eq
  1148   le_less_trans
  1149   less_le_trans
  1150   less_not_sym
  1151   less_asym
  1152 
  1153 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1154 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1155 and different variable names.
  1156 
  1157 * Library/Option_ord.thy: Canonical order on option type.
  1158 
  1159 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1160 finite maps.
  1161 
  1162 * Library/Countable.thy: Type class for countable types.
  1163 
  1164 * Theory Int: The representation of numerals has changed.  The infix
  1165 operator BIT and the bit datatype with constructors B0 and B1 have
  1166 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1167 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1168 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1169 accordingly.
  1170 
  1171 * Theory Nat: definition of <= and < on natural numbers no longer
  1172 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1173 le_def and less_def have disappeared.  Consider lemmas not_less
  1174 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1175 
  1176 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1177 (whose purpose mainly is for various fold_set functionals) have been
  1178 abandoned in favor of the existing algebraic classes
  1179 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1180 lower_semilattice (resp. upper_semilattice) and linorder.
  1181 INCOMPATIBILITY.
  1182 
  1183 * Theory Transitive_Closure: induct and cases rules now declare proper
  1184 case_names ("base" and "step").  INCOMPATIBILITY.
  1185 
  1186 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1187 lattices.  The form set-specific version is available as
  1188 Inductive.lfp_ordinal_induct_set.
  1189 
  1190 * Renamed theorems "power.simps" to "power_int.simps".
  1191 INCOMPATIBILITY.
  1192 
  1193 * Class semiring_div provides basic abstract properties of semirings
  1194 with division and modulo operations.  Subsumes former class dvd_mod.
  1195 
  1196 * Merged theories IntDef, Numeral and IntArith into unified theory
  1197 Int.  INCOMPATIBILITY.
  1198 
  1199 * Theory Library/Code_Index: type "index" now represents natural
  1200 numbers rather than integers.  INCOMPATIBILITY.
  1201 
  1202 * New class "uminus" with operation "uminus" (split of from class
  1203 "minus" which now only has operation "minus", binary).
  1204 INCOMPATIBILITY.
  1205 
  1206 * Constants "card", "internal_split", "option_map" now with authentic
  1207 syntax.  INCOMPATIBILITY.
  1208 
  1209 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1210 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1211 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1212 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1213 Sup_set_def, le_def, less_def, option_map_def now with object
  1214 equality.  INCOMPATIBILITY.
  1215 
  1216 * Records. Removed K_record, and replaced it by pure lambda term
  1217 %x. c. The simplifier setup is now more robust against eta expansion.
  1218 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1219 
  1220 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1221 
  1222 * Library/ListVector: new theory of arithmetic vector operations.
  1223 
  1224 * Library/Order_Relation: new theory of various orderings as sets of
  1225 pairs.  Defines preorders, partial orders, linear orders and
  1226 well-orders on sets and on types.
  1227 
  1228 
  1229 *** ZF ***
  1230 
  1231 * Renamed some theories to allow to loading both ZF and HOL in the
  1232 same session:
  1233 
  1234   Datatype  -> Datatype_ZF
  1235   Inductive -> Inductive_ZF
  1236   Int       -> Int_ZF
  1237   IntDiv    -> IntDiv_ZF
  1238   Nat       -> Nat_ZF
  1239   List      -> List_ZF
  1240   Main      -> Main_ZF
  1241 
  1242 INCOMPATIBILITY: ZF theories that import individual theories below
  1243 Main might need to be adapted.  Regular theory Main is still
  1244 available, as trivial extension of Main_ZF.
  1245 
  1246 
  1247 *** ML ***
  1248 
  1249 * ML within Isar: antiquotation @{const name} or @{const
  1250 name(typargs)} produces statically-checked Const term.
  1251 
  1252 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1253 (of the same name).  Removed obsolete print command.
  1254 
  1255 * Removed obsolete "use_legacy_bindings" function.
  1256 
  1257 * The ``print mode'' is now a thread-local value derived from a global
  1258 template (the former print_mode reference), thus access becomes
  1259 non-critical.  The global print_mode reference is for session
  1260 management only; user-code should use print_mode_value,
  1261 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1262 
  1263 * Functions system/system_out provide a robust way to invoke external
  1264 shell commands, with propagation of interrupts (requires Poly/ML
  1265 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1266 
  1267 
  1268 *** System ***
  1269 
  1270 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1271 in accordance with Proof General 3.7, which prefers GNU emacs.
  1272 
  1273 * isatool tty runs Isabelle process with plain tty interaction;
  1274 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1275 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1276 
  1277 * isatool browser now works with Cygwin as well, using general
  1278 "javapath" function defined in Isabelle process environment.
  1279 
  1280 * YXML notation provides a simple and efficient alternative to
  1281 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1282 isatool yxml as described in the Isabelle system manual.
  1283 
  1284 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1285 provides general wrapper for managing an Isabelle process in a robust
  1286 fashion, with ``cooked'' output from stdin/stderr.
  1287 
  1288 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1289 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1290 
  1291 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1292 way of changing the user's settings is via
  1293 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1294 script.
  1295 
  1296 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1297 cores of the underlying machine, which is a good starting point for
  1298 optimal performance tuning.  The corresponding usedir option -M allows
  1299 "max" as an alias for "0".  WARNING: does not work on certain versions
  1300 of Mac OS (with Poly/ML 5.1).
  1301 
  1302 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1303 adverse effect of Isabelle flooding interactive front-ends (notably
  1304 ProofGeneral / XEmacs).
  1305 
  1306 
  1307 
  1308 New in Isabelle2007 (November 2007)
  1309 -----------------------------------
  1310 
  1311 *** General ***
  1312 
  1313 * More uniform information about legacy features, notably a
  1314 warning/error of "Legacy feature: ...", depending on the state of the
  1315 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1316 legacy features will disappear eventually.
  1317 
  1318 * Theory syntax: the header format ``theory A = B + C:'' has been
  1319 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1320 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1321 
  1322 * Theory syntax: the old non-Isar theory file format has been
  1323 discontinued altogether.  Note that ML proof scripts may still be used
  1324 with Isar theories; migration is usually quite simple with the ML
  1325 function use_legacy_bindings.  INCOMPATIBILITY.
  1326 
  1327 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1328 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1329 quotes.
  1330 
  1331 * Theory loader: be more serious about observing the static theory
  1332 header specifications (including optional directories), but not the
  1333 accidental file locations of previously successful loads.  The strict
  1334 update policy of former update_thy is now already performed by
  1335 use_thy, so the former has been removed; use_thys updates several
  1336 theories simultaneously, just as 'imports' within a theory header
  1337 specification, but without merging the results.  Potential
  1338 INCOMPATIBILITY: may need to refine theory headers and commands
  1339 ROOT.ML which depend on load order.
  1340 
  1341 * Theory loader: optional support for content-based file
  1342 identification, instead of the traditional scheme of full physical
  1343 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1344 (cf. the system manual).  The new scheme allows to work with
  1345 non-finished theories in persistent session images, such that source
  1346 files may be moved later on without requiring reloads.
  1347 
  1348 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1349 file (with the same base name as the theory) are considered a legacy
  1350 feature, which will disappear eventually. Even now, the theory loader
  1351 no longer maintains dependencies on such files.
  1352 
  1353 * Syntax: the scope for resolving ambiguities via type-inference is
  1354 now limited to individual terms, instead of whole simultaneous
  1355 specifications as before. This greatly reduces the complexity of the
  1356 syntax module and improves flexibility by separating parsing and
  1357 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1358 'fixes' etc.) are required in rare situations.
  1359 
  1360 * Syntax: constants introduced by new-style packages ('definition',
  1361 'abbreviation' etc.) are passed through the syntax module in
  1362 ``authentic mode''. This means that associated mixfix annotations
  1363 really stick to such constants, independently of potential name space
  1364 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1365 trees are represented slightly differently, may need to adapt syntax
  1366 translations accordingly. Use CONST marker in 'translations' and
  1367 @{const_syntax} antiquotation in 'parse_translation' etc.
  1368 
  1369 * Legacy goal package: reduced interface to the bare minimum required
  1370 to keep existing proof scripts running.  Most other user-level
  1371 functions are now part of the OldGoals structure, which is *not* open
  1372 by default (consider isatool expandshort before open OldGoals).
  1373 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1374 these tend to cause confusion about the actual goal (!) context being
  1375 used here, which is not necessarily the same as the_context().
  1376 
  1377 * Command 'find_theorems': supports "*" wild-card in "name:"
  1378 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1379 support a specific search form (see ProofGeneral/CHANGES).
  1380 
  1381 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1382 by default, which means that "prems" (and also "fixed variables") are
  1383 suppressed from proof state output.  Note that the ProofGeneral
  1384 settings mechanism allows to change and save options persistently, but
  1385 older versions of Isabelle will fail to start up if a negative prems
  1386 limit is imposed.
  1387 
  1388 * Local theory targets may be specified by non-nested blocks of
  1389 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1390 contain definitions, theorems etc., including any derived mechanism
  1391 that has been implemented on top of these primitives.  This concept
  1392 generalizes the existing ``theorem (in ...)'' towards more versatility
  1393 and scalability.
  1394 
  1395 * Proof General interface: proper undo of final 'end' command;
  1396 discontinued Isabelle/classic mode (ML proof scripts).
  1397 
  1398 
  1399 *** Document preparation ***
  1400 
  1401 * Added antiquotation @{theory name} which prints the given name,
  1402 after checking that it refers to a valid ancestor theory in the
  1403 current context.
  1404 
  1405 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1406 check the given source text as ML type/structure, printing verbatim.
  1407 
  1408 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1409 "c args == rhs" given in the current context.  (Any number of
  1410 arguments may be given on the LHS.)
  1411 
  1412 
  1413 *** Pure ***
  1414 
  1415 * The 'class' package offers a combination of axclass and locale to
  1416 achieve Haskell-like type classes in Isabelle.  Definitions and
  1417 theorems within a class context produce both relative results (with
  1418 implicit parameters according to the locale context), and polymorphic
  1419 constants with qualified polymorphism (according to the class
  1420 context).  Within the body context of a 'class' target, a separate
  1421 syntax layer ("user space type system") takes care of converting
  1422 between global polymorphic consts and internal locale representation.
  1423 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1424 "isatool doc classes" provides a tutorial.
  1425 
  1426 * Generic code generator framework allows to generate executable
  1427 code for ML and Haskell (including Isabelle classes).  A short usage
  1428 sketch:
  1429 
  1430     internal compilation:
  1431         export_code <list of constants (term syntax)> in SML
  1432     writing SML code to a file:
  1433         export_code <list of constants (term syntax)> in SML <filename>
  1434     writing OCaml code to a file:
  1435         export_code <list of constants (term syntax)> in OCaml <filename>
  1436     writing Haskell code to a bunch of files:
  1437         export_code <list of constants (term syntax)> in Haskell <filename>
  1438 
  1439     evaluating closed propositions to True/False using code generation:
  1440         method ``eval''
  1441 
  1442 Reasonable default setup of framework in HOL.
  1443 
  1444 Theorem attributs for selecting and transforming function equations theorems:
  1445 
  1446     [code fun]:        select a theorem as function equation for a specific constant
  1447     [code fun del]:    deselect a theorem as function equation for a specific constant
  1448     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1449     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1450 
  1451 User-defined serializations (target in {SML, OCaml, Haskell}):
  1452 
  1453     code_const <and-list of constants (term syntax)>
  1454       {(target) <and-list of const target syntax>}+
  1455 
  1456     code_type <and-list of type constructors>
  1457       {(target) <and-list of type target syntax>}+
  1458 
  1459     code_instance <and-list of instances>
  1460       {(target)}+
  1461         where instance ::= <type constructor> :: <class>
  1462 
  1463     code_class <and_list of classes>
  1464       {(target) <and-list of class target syntax>}+
  1465         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1466 
  1467 code_instance and code_class only are effective to target Haskell.
  1468 
  1469 For example usage see src/HOL/ex/Codegenerator.thy and
  1470 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1471 generation from Isabelle/HOL theories is available via "isatool doc
  1472 codegen".
  1473 
  1474 * Code generator: consts in 'consts_code' Isar commands are now
  1475 referred to by usual term syntax (including optional type
  1476 annotations).
  1477 
  1478 * Command 'no_translations' removes translation rules from theory
  1479 syntax.
  1480 
  1481 * Overloaded definitions are now actually checked for acyclic
  1482 dependencies.  The overloading scheme is slightly more general than
  1483 that of Haskell98, although Isabelle does not demand an exact
  1484 correspondence to type class and instance declarations.
  1485 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1486 exotic versions of overloading -- at the discretion of the user!
  1487 
  1488 Polymorphic constants are represented via type arguments, i.e. the
  1489 instantiation that matches an instance against the most general
  1490 declaration given in the signature.  For example, with the declaration
  1491 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1492 as c(nat).  Overloading is essentially simultaneous structural
  1493 recursion over such type arguments.  Incomplete specification patterns
  1494 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1495 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1496 Command 'print_theory' outputs the normalized system of recursive
  1497 equations, see section "definitions".
  1498 
  1499 * Configuration options are maintained within the theory or proof
  1500 context (with name and type bool/int/string), providing a very simple
  1501 interface to a poor-man's version of general context data.  Tools may
  1502 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1503 these values using Config.get etc.  Users may change options via an
  1504 associated attribute of the same name.  This form of context
  1505 declaration works particularly well with commands 'declare' or
  1506 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1507 very easy to avoid global references, which would not observe Isar
  1508 toplevel undo/redo and fail to work with multithreading.
  1509 
  1510 Various global ML references of Pure and HOL have been turned into
  1511 configuration options:
  1512 
  1513   Unify.search_bound		unify_search_bound
  1514   Unify.trace_bound		unify_trace_bound
  1515   Unify.trace_simp		unify_trace_simp
  1516   Unify.trace_types		unify_trace_types
  1517   Simplifier.simp_depth_limit	simp_depth_limit
  1518   Blast.depth_limit		blast_depth_limit
  1519   DatatypeProp.dtK		datatype_distinctness_limit
  1520   fast_arith_neq_limit  	fast_arith_neq_limit
  1521   fast_arith_split_limit	fast_arith_split_limit
  1522 
  1523 * Named collections of theorems may be easily installed as context
  1524 data using the functor NamedThmsFun (see also
  1525 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1526 attributes; there is also a toplevel print command.  This facility is
  1527 just a common case of general context data, which is the preferred way
  1528 for anything more complex than just a list of facts in canonical
  1529 order.
  1530 
  1531 * Isar: command 'declaration' augments a local theory by generic
  1532 declaration functions written in ML.  This enables arbitrary content
  1533 being added to the context, depending on a morphism that tells the
  1534 difference of the original declaration context wrt. the application
  1535 context encountered later on.
  1536 
  1537 * Isar: proper interfaces for simplification procedures.  Command
  1538 'simproc_setup' declares named simprocs (with match patterns, and body
  1539 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1540 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1541 
  1542 * Isar: an extra pair of brackets around attribute declarations
  1543 abbreviates a theorem reference involving an internal dummy fact,
  1544 which will be ignored later --- only the effect of the attribute on
  1545 the background context will persist.  This form of in-place
  1546 declarations is particularly useful with commands like 'declare' and
  1547 'using', for example ``have A using [[simproc a]] by simp''.
  1548 
  1549 * Isar: method "assumption" (and implicit closing of subproofs) now
  1550 takes simple non-atomic goal assumptions into account: after applying
  1551 an assumption as a rule the resulting subgoals are solved by atomic
  1552 assumption steps.  This is particularly useful to finish 'obtain'
  1553 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1554 without referring to the original premise "!!x. P x ==> thesis" in the
  1555 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1556 more permissive.
  1557 
  1558 * Isar: implicit use of prems from the Isar proof context is
  1559 considered a legacy feature.  Common applications like ``have A .''
  1560 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1561 referencing facts explicitly here improves readability and
  1562 maintainability of proof texts.
  1563 
  1564 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1565 the obtained context from the course of reasoning!  For example:
  1566 
  1567   assume "EX x y. A x & B y"   -- "any previous fact"
  1568   then guess x and y by clarify
  1569 
  1570 This technique is potentially adventurous, depending on the facts and
  1571 proof tools being involved here.
  1572 
  1573 * Isar: known facts from the proof context may be specified as literal
  1574 propositions, using ASCII back-quote syntax.  This works wherever
  1575 named facts used to be allowed so far, in proof commands, proof
  1576 methods, attributes etc.  Literal facts are retrieved from the context
  1577 according to unification of type and term parameters.  For example,
  1578 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1579 theorems in the current context, then these are valid literal facts:
  1580 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1581 
  1582 There is also a proof method "fact" which does the same composition
  1583 for explicit goal states, e.g. the following proof texts coincide with
  1584 certain special cases of literal facts:
  1585 
  1586   have "A" by fact                 ==  note `A`
  1587   have "A ==> B" by fact           ==  note `A ==> B`
  1588   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1589   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1590 
  1591 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1592 outer syntax.  Thus symbolic identifiers may be used without
  1593 additional white space in declarations like this: ``assume *: A''.
  1594 
  1595 * Isar: 'print_facts' prints all local facts of the current context,
  1596 both named and unnamed ones.
  1597 
  1598 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1599 
  1600   def x == "t" and y == "u"
  1601 
  1602 * Isar: added command 'unfolding', which is structurally similar to
  1603 'using', but affects both the goal state and facts by unfolding given
  1604 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1605 'unfolded' attribute may be replaced by first-class proof text.
  1606 
  1607 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1608 and command 'unfolding' now all support object-level equalities
  1609 (potentially conditional).  The underlying notion of rewrite rule is
  1610 analogous to the 'rule_format' attribute, but *not* that of the
  1611 Simplifier (which is usually more generous).
  1612 
  1613 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1614 premises of a theorem by n. Useful in conjunction with drule.
  1615 
  1616 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1617 method expression within a sandbox consisting of the first N
  1618 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1619 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1620 simplifies all new goals that emerge from applying rule foo to the
  1621 originally first one.
  1622 
  1623 * Isar: schematic goals are no longer restricted to higher-order
  1624 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1625 expected.
  1626 
  1627 * Isar: the conclusion of a long theorem statement is now either
  1628 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1629 (essentially a disjunction of cases with local parameters and
  1630 assumptions).  The latter allows to express general elimination rules
  1631 adequately; in this notation common elimination rules look like this:
  1632 
  1633   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1634     assumes "EX x. P x"
  1635     obtains x where "P x"
  1636 
  1637   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1638     assumes "A & B"
  1639     obtains A and B
  1640 
  1641   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1642     assumes "A | B"
  1643     obtains
  1644       A
  1645     | B
  1646 
  1647 The subsequent classical rules even refer to the formal "thesis"
  1648 explicitly:
  1649 
  1650   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1651     obtains "~ thesis"
  1652 
  1653   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1654     obtains "thesis ==> something"
  1655 
  1656 The actual proof of an 'obtains' statement is analogous to that of the
  1657 Isar proof element 'obtain', only that there may be several cases.
  1658 Optional case names may be specified in parentheses; these will be
  1659 available both in the present proof and as annotations in the
  1660 resulting rule, for later use with the 'cases' method (cf. attribute
  1661 case_names).
  1662 
  1663 * Isar: the assumptions of a long theorem statement are available as
  1664 "assms" fact in the proof context.  This is more appropriate than the
  1665 (historical) "prems", which refers to all assumptions of the current
  1666 context, including those from the target locale, proof body etc.
  1667 
  1668 * Isar: 'print_statement' prints theorems from the current theory or
  1669 proof context in long statement form, according to the syntax of a
  1670 top-level lemma.
  1671 
  1672 * Isar: 'obtain' takes an optional case name for the local context
  1673 introduction rule (default "that").
  1674 
  1675 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1676 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1677 to occur.
  1678 
  1679 * Pure: syntax "CONST name" produces a fully internalized constant
  1680 according to the current context.  This is particularly useful for
  1681 syntax translations that should refer to internal constant
  1682 representations independently of name spaces.
  1683 
  1684 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1685 instead of "FOO ". This allows multiple binder declarations to coexist
  1686 in the same context.  INCOMPATIBILITY.
  1687 
  1688 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1689 primitive that also works in a locale context (both for constants and
  1690 fixed variables). Type declaration and internal syntactic representation
  1691 of given constants retrieved from the context. Likewise, the
  1692 'no_notation' command allows to remove given syntax annotations from the
  1693 current context.
  1694 
  1695 * Isar/locales: new derived specification elements 'axiomatization',
  1696 'definition', 'abbreviation', which support type-inference, admit
  1697 object-level specifications (equality, equivalence).  See also the
  1698 isar-ref manual.  Examples:
  1699 
  1700   axiomatization
  1701     eq  (infix "===" 50) where
  1702     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1703 
  1704   definition "f x y = x + y + 1"
  1705   definition g where "g x = f x x"
  1706 
  1707   abbreviation
  1708     neq  (infix "=!=" 50) where
  1709     "x =!= y == ~ (x === y)"
  1710 
  1711 These specifications may be also used in a locale context.  Then the
  1712 constants being introduced depend on certain fixed parameters, and the
  1713 constant name is qualified by the locale base name.  An internal
  1714 abbreviation takes care for convenient input and output, making the
  1715 parameters implicit and using the original short name.  See also
  1716 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1717 entities from a monomorphic theory.
  1718 
  1719 Presently, abbreviations are only available 'in' a target locale, but
  1720 not inherited by general import expressions.  Also note that
  1721 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1722 'translations' in common applications.  The "no_abbrevs" print mode
  1723 prevents folding of abbreviations in term output.
  1724 
  1725 Concrete syntax is attached to specified constants in internal form,
  1726 independently of name spaces.  The parse tree representation is
  1727 slightly different -- use 'notation' instead of raw 'syntax', and
  1728 'translations' with explicit "CONST" markup to accommodate this.
  1729 
  1730 * Pure/Isar: unified syntax for new-style specification mechanisms
  1731 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1732 full type inference and dummy patterns ("_").  For example:
  1733 
  1734   definition "K x _ = x"
  1735 
  1736   inductive conj for A B
  1737   where "A ==> B ==> conj A B"
  1738 
  1739 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1740 the current context.  Print mode "no_abbrevs" prevents inversion of
  1741 abbreviations on output.
  1742 
  1743 * Isar/locales: improved parameter handling: use of locales "var" and
  1744 "struct" no longer necessary; - parameter renamings are no longer
  1745 required to be injective.  For example, this allows to define
  1746 endomorphisms as locale endom = homom mult mult h.
  1747 
  1748 * Isar/locales: changed the way locales with predicates are defined.
  1749 Instead of accumulating the specification, the imported expression is
  1750 now an interpretation.  INCOMPATIBILITY: different normal form of
  1751 locale expressions.  In particular, in interpretations of locales with
  1752 predicates, goals repesenting already interpreted fragments are not
  1753 removed automatically.  Use methods `intro_locales' and
  1754 `unfold_locales'; see below.
  1755 
  1756 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1757 provide backward reasoning on locales predicates.  The methods are
  1758 aware of interpretations and discharge corresponding goals.
  1759 `intro_locales' is less aggressive then `unfold_locales' and does not
  1760 unfold predicates to assumptions.
  1761 
  1762 * Isar/locales: the order in which locale fragments are accumulated
  1763 has changed.  This enables to override declarations from fragments due
  1764 to interpretations -- for example, unwanted simp rules.
  1765 
  1766 * Isar/locales: interpretation in theories and proof contexts has been
  1767 extended.  One may now specify (and prove) equations, which are
  1768 unfolded in interpreted theorems.  This is useful for replacing
  1769 defined concepts (constants depending on locale parameters) by
  1770 concepts already existing in the target context.  Example:
  1771 
  1772   interpretation partial_order ["op <= :: [int, int] => bool"]
  1773     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1774 
  1775 Typically, the constant `partial_order.less' is created by a
  1776 definition specification element in the context of locale
  1777 partial_order.
  1778 
  1779 * Method "induct": improved internal context management to support
  1780 local fixes and defines on-the-fly. Thus explicit meta-level
  1781 connectives !!  and ==> are rarely required anymore in inductive goals
  1782 (using object-logic connectives for this purpose has been long
  1783 obsolete anyway). Common proof patterns are explained in
  1784 src/HOL/Induct/Common_Patterns.thy, see also
  1785 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1786 examples.
  1787 
  1788 * Method "induct": improved handling of simultaneous goals. Instead of
  1789 introducing object-level conjunction, the statement is now split into
  1790 several conclusions, while the corresponding symbolic cases are nested
  1791 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1792 see src/HOL/Induct/Common_Patterns.thy, for example.
  1793 
  1794 * Method "induct": mutual induction rules are now specified as a list
  1795 of rule sharing the same induction cases. HOL packages usually provide
  1796 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1797 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1798 mutual induction rules differently, i.e. like this:
  1799 
  1800   (induct rule: foo_bar.inducts)
  1801   (induct set: foo bar)
  1802   (induct pred: foo bar)
  1803   (induct type: foo bar)
  1804 
  1805 The ML function ProjectRule.projections turns old-style rules into the
  1806 new format.
  1807 
  1808 * Method "coinduct": dual of induction, see
  1809 src/HOL/Library/Coinductive_List.thy for various examples.
  1810 
  1811 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1812 considered a legacy feature.
  1813 
  1814 * Attribute "symmetric" produces result with standardized schematic
  1815 variables (index 0).  Potential INCOMPATIBILITY.
  1816 
  1817 * Simplifier: by default the simplifier trace only shows top level
  1818 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1819 default. Thus there is less danger of being flooded by the trace. The
  1820 trace indicates where parts have been suppressed.
  1821   
  1822 * Provers/classical: removed obsolete classical version of elim_format
  1823 attribute; classical elim/dest rules are now treated uniformly when
  1824 manipulating the claset.
  1825 
  1826 * Provers/classical: stricter checks to ensure that supplied intro,
  1827 dest and elim rules are well-formed; dest and elim rules must have at
  1828 least one premise.
  1829 
  1830 * Provers/classical: attributes dest/elim/intro take an optional
  1831 weight argument for the rule (just as the Pure versions).  Weights are
  1832 ignored by automated tools, but determine the search order of single
  1833 rule steps.
  1834 
  1835 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1836 where the body does not mention the bound variable.  Note that dummy
  1837 patterns implicitly depend on their context of bounds, which makes
  1838 "{_. _}" match any set comprehension as expected.  Potential
  1839 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1840 constant "_idtdummy" in the binding position.
  1841 
  1842 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1843 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1844 for example "A -> B" => "Pi A (%_. B)".
  1845 
  1846 * Pure: 'class_deps' command visualizes the subclass relation, using
  1847 the graph browser tool.
  1848 
  1849 * Pure: 'print_theory' now suppresses certain internal declarations by
  1850 default; use '!' option for full details.
  1851 
  1852 
  1853 *** HOL ***
  1854 
  1855 * Method "metis" proves goals by applying the Metis general-purpose
  1856 resolution prover (see also http://gilith.com/software/metis/).
  1857 Examples are in the directory MetisExamples.  WARNING: the
  1858 Isabelle/HOL-Metis integration does not yet work properly with
  1859 multi-threading.
  1860   
  1861 * Command 'sledgehammer' invokes external automatic theorem provers as
  1862 background processes.  It generates calls to the "metis" method if
  1863 successful. These can be pasted into the proof.  Users do not have to
  1864 wait for the automatic provers to return.  WARNING: does not really
  1865 work with multi-threading.
  1866 
  1867 * New "auto_quickcheck" feature tests outermost goal statements for
  1868 potential counter-examples.  Controlled by ML references
  1869 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1870 5000 milliseconds).  Fails silently if statements is outside of
  1871 executable fragment, or any other codgenerator problem occurs.
  1872 
  1873 * New constant "undefined" with axiom "undefined x = undefined".
  1874 
  1875 * Added class "HOL.eq", allowing for code generation with polymorphic
  1876 equality.
  1877 
  1878 * Some renaming of class constants due to canonical name prefixing in
  1879 the new 'class' package:
  1880 
  1881     HOL.abs ~> HOL.abs_class.abs
  1882     HOL.divide ~> HOL.divide_class.divide
  1883     0 ~> HOL.zero_class.zero
  1884     1 ~> HOL.one_class.one
  1885     op + ~> HOL.plus_class.plus
  1886     op - ~> HOL.minus_class.minus
  1887     uminus ~> HOL.minus_class.uminus
  1888     op * ~> HOL.times_class.times
  1889     op < ~> HOL.ord_class.less
  1890     op <= > HOL.ord_class.less_eq
  1891     Nat.power ~> Power.power_class.power
  1892     Nat.size ~> Nat.size_class.size
  1893     Numeral.number_of ~> Numeral.number_class.number_of
  1894     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1895     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1896     Orderings.min ~> Orderings.ord_class.min
  1897     Orderings.max ~> Orderings.ord_class.max
  1898     Divides.op div ~> Divides.div_class.div
  1899     Divides.op mod ~> Divides.div_class.mod
  1900     Divides.op dvd ~> Divides.div_class.dvd
  1901 
  1902 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1903 
  1904 a) User-defined constants using any of the names "plus", "minus",
  1905 "times", "less" or "less_eq". The standard syntax translations for
  1906 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1907 names.
  1908 
  1909 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1910 INCOMPATIBILITY: use more specific names.
  1911 
  1912 c) Permutative equations (e.g. "a + b = b + a")
  1913 Since the change of names also changes the order of terms, permutative
  1914 rewrite rules may get applied in a different order. Experience shows
  1915 that this is rarely the case (only two adaptions in the whole Isabelle
  1916 distribution).  INCOMPATIBILITY: rewrite proofs
  1917 
  1918 d) ML code directly refering to constant names
  1919 This in general only affects hand-written proof tactics, simprocs and
  1920 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1921 Consider using @{const_name} antiquotation.
  1922 
  1923 * New class "default" with associated constant "default".
  1924 
  1925 * Function "sgn" is now overloaded and available on int, real, complex
  1926 (and other numeric types), using class "sgn".  Two possible defs of
  1927 sgn are given as equational assumptions in the classes sgn_if and
  1928 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1929 INCOMPATIBILITY.
  1930 
  1931 * Locale "partial_order" now unified with class "order" (cf. theory
  1932 Orderings), added parameter "less".  INCOMPATIBILITY.
  1933 
  1934 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1935 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1936 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1937 
  1938 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1939 changed order of proof goals in instance proofs.
  1940 
  1941 * The transitivity reasoner for partial and linear orders is set up
  1942 for classes "order" and "linorder".  Instances of the reasoner are available
  1943 in all contexts importing or interpreting the corresponding locales.
  1944 Method "order" invokes the reasoner separately; the reasoner
  1945 is also integrated with the Simplifier as a solver.  Diagnostic
  1946 command 'print_orders' shows the available instances of the reasoner
  1947 in the current context.
  1948 
  1949 * Localized monotonicity predicate in theory "Orderings"; integrated
  1950 lemmas max_of_mono and min_of_mono with this predicate.
  1951 INCOMPATIBILITY.
  1952 
  1953 * Formulation of theorem "dense" changed slightly due to integration
  1954 with new class dense_linear_order.
  1955 
  1956 * Uniform lattice theory development in HOL.
  1957 
  1958     constants "meet" and "join" now named "inf" and "sup"
  1959     constant "Meet" now named "Inf"
  1960 
  1961     classes "meet_semilorder" and "join_semilorder" now named
  1962       "lower_semilattice" and "upper_semilattice"
  1963     class "lorder" now named "lattice"
  1964     class "comp_lat" now named "complete_lattice"
  1965 
  1966     Instantiation of lattice classes allows explicit definitions
  1967     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1968 
  1969   INCOMPATIBILITY.  Theorem renames:
  1970 
  1971     meet_left_le            ~> inf_le1
  1972     meet_right_le           ~> inf_le2
  1973     join_left_le            ~> sup_ge1
  1974     join_right_le           ~> sup_ge2
  1975     meet_join_le            ~> inf_sup_ord
  1976     le_meetI                ~> le_infI
  1977     join_leI                ~> le_supI
  1978     le_meet                 ~> le_inf_iff
  1979     le_join                 ~> ge_sup_conv
  1980     meet_idempotent         ~> inf_idem
  1981     join_idempotent         ~> sup_idem
  1982     meet_comm               ~> inf_commute
  1983     join_comm               ~> sup_commute
  1984     meet_leI1               ~> le_infI1
  1985     meet_leI2               ~> le_infI2
  1986     le_joinI1               ~> le_supI1
  1987     le_joinI2               ~> le_supI2
  1988     meet_assoc              ~> inf_assoc
  1989     join_assoc              ~> sup_assoc
  1990     meet_left_comm          ~> inf_left_commute
  1991     meet_left_idempotent    ~> inf_left_idem
  1992     join_left_comm          ~> sup_left_commute
  1993     join_left_idempotent    ~> sup_left_idem
  1994     meet_aci                ~> inf_aci
  1995     join_aci                ~> sup_aci
  1996     le_def_meet             ~> le_iff_inf
  1997     le_def_join             ~> le_iff_sup
  1998     join_absorp2            ~> sup_absorb2
  1999     join_absorp1            ~> sup_absorb1
  2000     meet_absorp1            ~> inf_absorb1
  2001     meet_absorp2            ~> inf_absorb2
  2002     meet_join_absorp        ~> inf_sup_absorb
  2003     join_meet_absorp        ~> sup_inf_absorb
  2004     distrib_join_le         ~> distrib_sup_le
  2005     distrib_meet_le         ~> distrib_inf_le
  2006 
  2007     add_meet_distrib_left   ~> add_inf_distrib_left
  2008     add_join_distrib_left   ~> add_sup_distrib_left
  2009     is_join_neg_meet        ~> is_join_neg_inf
  2010     is_meet_neg_join        ~> is_meet_neg_sup
  2011     add_meet_distrib_right  ~> add_inf_distrib_right
  2012     add_join_distrib_right  ~> add_sup_distrib_right
  2013     add_meet_join_distribs  ~> add_sup_inf_distribs
  2014     join_eq_neg_meet        ~> sup_eq_neg_inf
  2015     meet_eq_neg_join        ~> inf_eq_neg_sup
  2016     add_eq_meet_join        ~> add_eq_inf_sup
  2017     meet_0_imp_0            ~> inf_0_imp_0
  2018     join_0_imp_0            ~> sup_0_imp_0
  2019     meet_0_eq_0             ~> inf_0_eq_0
  2020     join_0_eq_0             ~> sup_0_eq_0
  2021     neg_meet_eq_join        ~> neg_inf_eq_sup
  2022     neg_join_eq_meet        ~> neg_sup_eq_inf
  2023     join_eq_if              ~> sup_eq_if
  2024 
  2025     mono_meet               ~> mono_inf
  2026     mono_join               ~> mono_sup
  2027     meet_bool_eq            ~> inf_bool_eq
  2028     join_bool_eq            ~> sup_bool_eq
  2029     meet_fun_eq             ~> inf_fun_eq
  2030     join_fun_eq             ~> sup_fun_eq
  2031     meet_set_eq             ~> inf_set_eq
  2032     join_set_eq             ~> sup_set_eq
  2033     meet1_iff               ~> inf1_iff
  2034     meet2_iff               ~> inf2_iff
  2035     meet1I                  ~> inf1I
  2036     meet2I                  ~> inf2I
  2037     meet1D1                 ~> inf1D1
  2038     meet2D1                 ~> inf2D1
  2039     meet1D2                 ~> inf1D2
  2040     meet2D2                 ~> inf2D2
  2041     meet1E                  ~> inf1E
  2042     meet2E                  ~> inf2E
  2043     join1_iff               ~> sup1_iff
  2044     join2_iff               ~> sup2_iff
  2045     join1I1                 ~> sup1I1
  2046     join2I1                 ~> sup2I1
  2047     join1I1                 ~> sup1I1
  2048     join2I2                 ~> sup1I2
  2049     join1CI                 ~> sup1CI
  2050     join2CI                 ~> sup2CI
  2051     join1E                  ~> sup1E
  2052     join2E                  ~> sup2E
  2053 
  2054     is_meet_Meet            ~> is_meet_Inf
  2055     Meet_bool_def           ~> Inf_bool_def
  2056     Meet_fun_def            ~> Inf_fun_def
  2057     Meet_greatest           ~> Inf_greatest
  2058     Meet_lower              ~> Inf_lower
  2059     Meet_set_def            ~> Inf_set_def
  2060 
  2061     Sup_def                 ~> Sup_Inf
  2062     Sup_bool_eq             ~> Sup_bool_def
  2063     Sup_fun_eq              ~> Sup_fun_def
  2064     Sup_set_eq              ~> Sup_set_def
  2065 
  2066     listsp_meetI            ~> listsp_infI
  2067     listsp_meet_eq          ~> listsp_inf_eq
  2068 
  2069     meet_min                ~> inf_min
  2070     join_max                ~> sup_max
  2071 
  2072 * Added syntactic class "size"; overloaded constant "size" now has
  2073 type "'a::size ==> bool"
  2074 
  2075 * Internal reorganisation of `size' of datatypes: size theorems
  2076 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2077 simplification rules by default!); theorems "prod.size" now named
  2078 "*.size".
  2079 
  2080 * Class "div" now inherits from class "times" rather than "type".
  2081 INCOMPATIBILITY.
  2082 
  2083 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2084 Linorder etc.  have disappeared; operations defined in terms of
  2085 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2086 
  2087 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2088 
  2089 * HOL-Word: New extensive library and type for generic, fixed size
  2090 machine words, with arithemtic, bit-wise, shifting and rotating
  2091 operations, reflection into int, nat, and bool lists, automation for
  2092 linear arithmetic (by automatic reflection into nat or int), including
  2093 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2094 arithmetic type classes, supporting automatic simplification of
  2095 numerals on all operations.
  2096 
  2097 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2098 
  2099 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2100 
  2101 * Code generator library theories:
  2102   - Code_Integer represents HOL integers by big integer literals in target
  2103     languages.
  2104   - Code_Char represents HOL characters by character literals in target
  2105     languages.
  2106   - Code_Char_chr like Code_Char, but also offers treatment of character
  2107     codes; includes Code_Integer.
  2108   - Executable_Set allows to generate code for finite sets using lists.
  2109   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2110     denominator).
  2111   - Executable_Real implements a subset of real numbers, namly those
  2112     representable by rational numbers.
  2113   - Efficient_Nat implements natural numbers by integers, which in general will
  2114     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2115     includes Code_Integer.
  2116   - Code_Index provides an additional datatype index which is mapped to
  2117     target-language built-in integers.
  2118   - Code_Message provides an additional datatype message_string which is isomorphic to
  2119     strings; messages are mapped to target-language strings.
  2120 
  2121 * New package for inductive predicates
  2122 
  2123   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2124 
  2125     inductive
  2126       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2127       for z_1 :: U_1 and ... and z_n :: U_m
  2128     where
  2129       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2130     | ...
  2131 
  2132   with full support for type-inference, rather than
  2133 
  2134     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2135 
  2136     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2137     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2138 
  2139     inductive "s z_1 ... z_m"
  2140     intros
  2141       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2142       ...
  2143 
  2144   For backward compatibility, there is a wrapper allowing inductive
  2145   sets to be defined with the new package via
  2146 
  2147     inductive_set
  2148       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2149       for z_1 :: U_1 and ... and z_n :: U_m
  2150     where
  2151       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2152     | ...
  2153 
  2154   or
  2155 
  2156     inductive_set
  2157       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2158       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2159       for z_1 :: U_1 and ... and z_n :: U_m
  2160     where
  2161       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2162     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2163     | ...
  2164 
  2165   if the additional syntax "p ..." is required.
  2166 
  2167   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2168   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2169 
  2170   INCOMPATIBILITIES:
  2171 
  2172   - Since declaration and definition of inductive sets or predicates
  2173     is no longer separated, abbreviations involving the newly
  2174     introduced sets or predicates must be specified together with the
  2175     introduction rules after the 'where' keyword (see above), rather
  2176     than before the actual inductive definition.
  2177 
  2178   - The variables in induction and elimination rules are now
  2179     quantified in the order of their occurrence in the introduction
  2180     rules, rather than in alphabetical order. Since this may break
  2181     some proofs, these proofs either have to be repaired, e.g. by
  2182     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2183     statements of the form
  2184 
  2185       case (rule_i a_i_1 ... a_i_{k_i})
  2186 
  2187     or the old order of quantification has to be restored by explicitly adding
  2188     meta-level quantifiers in the introduction rules, i.e.
  2189 
  2190       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2191 
  2192   - The format of the elimination rules is now
  2193 
  2194       p z_1 ... z_m x_1 ... x_n ==>
  2195         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2196         ==> ... ==> P
  2197 
  2198     for predicates and
  2199 
  2200       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2201         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2202         ==> ... ==> P
  2203 
  2204     for sets rather than
  2205 
  2206       x : s z_1 ... z_m ==>
  2207         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2208         ==> ... ==> P
  2209 
  2210     This may require terms in goals to be expanded to n-tuples
  2211     (e.g. using case_tac or simplification with the split_paired_all
  2212     rule) before the above elimination rule is applicable.
  2213 
  2214   - The elimination or case analysis rules for (mutually) inductive
  2215     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2216     list of rules "p_1_..._p_k.elims" is no longer available.
  2217 
  2218 * New package "function"/"fun" for general recursive functions,
  2219 supporting mutual and nested recursion, definitions in local contexts,
  2220 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2221 for small examples, and the separate tutorial on the function
  2222 package. The old recdef "package" is still available as before, but
  2223 users are encouraged to use the new package.
  2224 
  2225 * Method "lexicographic_order" automatically synthesizes termination
  2226 relations as lexicographic combinations of size measures. 
  2227 
  2228 * Case-expressions allow arbitrary constructor-patterns (including
  2229 "_") and take their order into account, like in functional
  2230 programming.  Internally, this is translated into nested
  2231 case-expressions; missing cases are added and mapped to the predefined
  2232 constant "undefined". In complicated cases printing may no longer show
  2233 the original input but the internal form. Lambda-abstractions allow
  2234 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2235 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2236 variable.
  2237 
  2238 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2239 is an abbreviation for "of_nat :: nat => int". The simplification
  2240 rules for "of_nat" have been changed to work like "int" did
  2241 previously.  Potential INCOMPATIBILITY:
  2242   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2243   - of_nat_diff and of_nat_mult are no longer default simp rules
  2244 
  2245 * Method "algebra" solves polynomial equations over (semi)rings using
  2246 Groebner bases. The (semi)ring structure is defined by locales and the
  2247 tool setup depends on that generic context. Installing the method for
  2248 a specific type involves instantiating the locale and possibly adding
  2249 declarations for computation on the coefficients.  The method is
  2250 already instantiated for natural numbers and for the axiomatic class
  2251 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2252 CALCULEMUS 2007 for the general principles underlying this
  2253 architecture of context-aware proof-tools.
  2254 
  2255 * Method "ferrack" implements quantifier elimination over
  2256 special-purpose dense linear orders using locales (analogous to
  2257 "algebra"). The method is already installed for class
  2258 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2259 rat, etc.
  2260 
  2261 * Former constant "List.op @" now named "List.append".  Use ML
  2262 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2263 circumvent possible incompatibilities when working on ML level.
  2264 
  2265 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2266 
  2267 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2268 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2269 
  2270 * New syntax for Haskell-like list comprehension (input only), eg.
  2271 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2272 
  2273 * The special syntax for function "filter" has changed from [x :
  2274 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2275 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2276 
  2277 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2278 defined on nat only, as an abbreviation for [a..<Suc b]
  2279 INCOMPATIBILITY.
  2280 
  2281 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2282 
  2283 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2284 
  2285 * New lemma collection field_simps (an extension of ring_simps) for
  2286 manipulating (in)equations involving division. Multiplies with all
  2287 denominators that can be proved to be non-zero (in equations) or
  2288 positive/negative (in inequations).
  2289 
  2290 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2291 have been improved and renamed to ring_simps, group_simps and
  2292 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2293 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2294 
  2295 * Theory Library/Commutative_Ring: switched from recdef to function
  2296 package; constants add, mul, pow now curried.  Infix syntax for
  2297 algebraic operations.
  2298 
  2299 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2300 INCOMPATIBILITY.
  2301 
  2302 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2303 INCOMPATIBILITY.
  2304 
  2305 * HOL/records: generalised field-update to take a function on the
  2306 field rather than the new value: r(|A := x|) is translated to A_update
  2307 (K x) r The K-combinator that is internally used is called K_record.
  2308 INCOMPATIBILITY: Usage of the plain update functions has to be
  2309 adapted.
  2310  
  2311 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2312 * x = 0, which are required for a semiring.  Richer structures do not
  2313 inherit from semiring_0 anymore, because this property is a theorem
  2314 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2315 there is more to prove, but this is mostly trivial.
  2316 
  2317 * Class "recpower" is generalized to arbitrary monoids, not just
  2318 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2319 commutativity or semiring properties additionally.
  2320 
  2321 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2322 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2323 better use 'abbreviation'.
  2324 
  2325 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2326 
  2327 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2328 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2329 significant changes for setting up numeral syntax for types:
  2330   - New constants Numeral.pred and Numeral.succ instead
  2331       of former Numeral.bin_pred and Numeral.bin_succ.
  2332   - Use integer operations instead of bin_add, bin_mult and so on.
  2333   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2334   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2335 
  2336 See src/HOL/Integ/IntArith.thy for an example setup.
  2337 
  2338 * Command 'normal_form' computes the normal form of a term that may
  2339 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2340 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2341 heavy-duty computations because the functions are compiled to ML
  2342 first.  Correspondingly, a method "normalization" is provided.  See
  2343 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2344 
  2345 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2346 25 like -->); output depends on the "iff" print_mode, the default is
  2347 "A = B" (with priority 50).
  2348 
  2349 * Relations less (<) and less_eq (<=) are also available on type bool.
  2350 Modified syntax to disallow nesting without explicit parentheses,
  2351 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2352 INCOMPATIBILITY.
  2353 
  2354 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2355 
  2356 * Relation composition operator "op O" now has precedence 75 and binds
  2357 stronger than union and intersection. INCOMPATIBILITY.
  2358 
  2359 * The old set interval syntax "{m..n(}" (and relatives) has been
  2360 removed.  Use "{m..<n}" (and relatives) instead.
  2361 
  2362 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2363 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2364 ``declare [[simproc del: neq]]''.
  2365 
  2366 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2367 True/False.
  2368 
  2369 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2370 
  2371 * Theorem setsum_mult renamed to setsum_right_distrib.
  2372 
  2373 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2374 ``rule'' method.
  2375 
  2376 * Reimplemented methods "sat" and "satx", with several improvements:
  2377 goals no longer need to be stated as "<prems> ==> False", equivalences
  2378 (i.e. "=" on type bool) are handled, variable names of the form
  2379 "lit_<n>" are no longer reserved, significant speedup.
  2380 
  2381 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2382 zChaff is still supported as well.
  2383 
  2384 * 'inductive' and 'datatype': provide projections of mutual rules,
  2385 bundled as foo_bar.inducts;
  2386 
  2387 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2388 Library.
  2389 
  2390 * Library: moved theory Accessible_Part to main HOL.
  2391 
  2392 * Library: added theory Coinductive_List of potentially infinite lists
  2393 as greatest fixed-point.
  2394 
  2395 * Library: added theory AssocList which implements (finite) maps as
  2396 association lists.
  2397 
  2398 * Method "evaluation" solves goals (i.e. a boolean expression)
  2399 efficiently by compiling it to ML.  The goal is "proved" (via an
  2400 oracle) if it evaluates to True.
  2401 
  2402 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2403 also when invoked by the simplifier.  This results in the Simplifier
  2404 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2405 Configuration option fast_arith_split_limit=0 recovers the old
  2406 behavior.
  2407 
  2408 * Support for hex (0x20) and binary (0b1001) numerals.
  2409 
  2410 * New method: reify eqs (t), where eqs are equations for an
  2411 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2412 parameter, computes a term s::'b and a list xs::'a list and proves the
  2413 theorem I xs s = t. This is also known as reification or quoting. The
  2414 resulting theorem is applied to the subgoal to substitute t with I xs
  2415 s.  If t is omitted, the subgoal itself is reified.
  2416 
  2417 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2418 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2419 where f is supposed to be a computable function (in the sense of code
  2420 generattion). The method uses reify to compute s and xs as above then
  2421 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2422 r and finally gets the theorem t = r, which is again applied to the
  2423 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2424 
  2425 * Reflection: Automatic reification now handels binding, an example is
  2426 available in src/HOL/ex/ReflectionEx.thy
  2427 
  2428 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2429 command 'statespace' that is similar to 'record', but introduces an
  2430 abstract specification based on the locale infrastructure instead of
  2431 HOL types.  This leads to extra flexibility in composing state spaces,
  2432 in particular multiple inheritance and renaming of components.
  2433 
  2434 
  2435 *** HOL-Complex ***
  2436 
  2437 * Hyperreal: Functions root and sqrt are now defined on negative real
  2438 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2439 Nonnegativity side conditions have been removed from many lemmas, so
  2440 that more subgoals may now be solved by simplification; potential
  2441 INCOMPATIBILITY.
  2442 
  2443 * Real: new type classes formalize real normed vector spaces and
  2444 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2445 and norm :: 'a => real.
  2446 
  2447 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2448 reals into other types. The overloaded constant Reals :: 'a set is now
  2449 defined as range of_real; potential INCOMPATIBILITY.
  2450 
  2451 * Real: proper support for ML code generation, including 'quickcheck'.
  2452 Reals are implemented as arbitrary precision rationals.
  2453 
  2454 * Hyperreal: Several constants that previously worked only for the
  2455 reals have been generalized, so they now work over arbitrary vector
  2456 spaces. Type annotations may need to be added in some cases; potential
  2457 INCOMPATIBILITY.
  2458 
  2459   Infinitesimal  :: ('a::real_normed_vector) star set
  2460   HFinite        :: ('a::real_normed_vector) star set
  2461   HInfinite      :: ('a::real_normed_vector) star set
  2462   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2463   monad          :: ('a::real_normed_vector) star => 'a star set
  2464   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2465   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2466   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2467   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2468   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2469   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2470   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2471   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2472   sgn            :: 'a::real_normed_vector => 'a
  2473   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2474 
  2475 * Complex: Some complex-specific constants are now abbreviations for
  2476 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2477 hnorm.  Other constants have been entirely removed in favor of the
  2478 polymorphic versions (INCOMPATIBILITY):
  2479 
  2480   approx        <-- capprox
  2481   HFinite       <-- CFinite
  2482   HInfinite     <-- CInfinite
  2483   Infinitesimal <-- CInfinitesimal
  2484   monad         <-- cmonad
  2485   galaxy        <-- cgalaxy
  2486   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2487   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2488   (ns)deriv     <-- (ns)cderiv
  2489 
  2490 
  2491 *** HOL-Algebra ***
  2492 
  2493 * Formalisation of ideals and the quotient construction over rings.
  2494 
  2495 * Order and lattice theory no longer based on records.
  2496 INCOMPATIBILITY.
  2497 
  2498 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2499 greatest_closed.  INCOMPATIBILITY.
  2500 
  2501 * Method algebra is now set up via an attribute.  For examples see
  2502 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2503 of algebraic structures.
  2504 
  2505 * Renamed theory CRing to Ring.
  2506 
  2507 
  2508 *** HOL-Nominal ***
  2509 
  2510 * Substantial, yet incomplete support for nominal datatypes (binding
  2511 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2512 src/HOL/Nominal/Examples.  Prospective users should consult
  2513 http://isabelle.in.tum.de/nominal/
  2514 
  2515 
  2516 *** ML ***
  2517 
  2518 * ML basics: just one true type int, which coincides with IntInf.int
  2519 (even on SML/NJ).
  2520 
  2521 * ML within Isar: antiquotations allow to embed statically-checked
  2522 formal entities in the source, referring to the context available at
  2523 compile-time.  For example:
  2524 
  2525 ML {* @{sort "{zero,one}"} *}
  2526 ML {* @{typ "'a => 'b"} *}
  2527 ML {* @{term "%x. x"} *}
  2528 ML {* @{prop "x == y"} *}
  2529 ML {* @{ctyp "'a => 'b"} *}
  2530 ML {* @{cterm "%x. x"} *}
  2531 ML {* @{cprop "x == y"} *}
  2532 ML {* @{thm asm_rl} *}
  2533 ML {* @{thms asm_rl} *}
  2534 ML {* @{type_name c} *}
  2535 ML {* @{type_syntax c} *}
  2536 ML {* @{const_name c} *}
  2537 ML {* @{const_syntax c} *}
  2538 ML {* @{context} *}
  2539 ML {* @{theory} *}
  2540 ML {* @{theory Pure} *}
  2541 ML {* @{theory_ref} *}
  2542 ML {* @{theory_ref Pure} *}
  2543 ML {* @{simpset} *}
  2544 ML {* @{claset} *}
  2545 ML {* @{clasimpset} *}
  2546 
  2547 The same works for sources being ``used'' within an Isar context.
  2548 
  2549 * ML in Isar: improved error reporting; extra verbosity with
  2550 ML_Context.trace enabled.
  2551 
  2552 * Pure/General/table.ML: the join operations now works via exceptions
  2553 DUP/SAME instead of type option. This is simpler in simple cases, and
  2554 admits slightly more efficient complex applications.
  2555 
  2556 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2557 use Context.generic instead of just theory.
  2558 
  2559 * Pure: datatype Context.generic joins theory/Proof.context and
  2560 provides some facilities for code that works in either kind of
  2561 context, notably GenericDataFun for uniform theory and proof data.
  2562 
  2563 * Pure: simplified internal attribute type, which is now always
  2564 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2565 local (Proof.context) attributes have been discontinued, while
  2566 minimizing code duplication. Thm.rule_attribute and
  2567 Thm.declaration_attribute build canonical attributes; see also structure
  2568 Context for further operations on Context.generic, notably
  2569 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2570 declarations and definitions.
  2571 
  2572 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2573 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2574 init only required for impure data. INCOMPATIBILITY: empty really need
  2575 to be empty (no dependencies on theory content!)
  2576 
  2577 * Pure/kernel: consts certification ignores sort constraints given in
  2578 signature declarations. (This information is not relevant to the
  2579 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2580 potential INCOMPATIBILITY.
  2581 
  2582 * Pure: axiomatic type classes are now purely definitional, with
  2583 explicit proofs of class axioms and super class relations performed
  2584 internally. See Pure/axclass.ML for the main internal interfaces --
  2585 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2586 AxClass.axiomatize_class/classrel/arity supersede
  2587 Sign.add_classes/classrel/arities.
  2588 
  2589 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2590 global/local versions on theory vs. Proof.context have been
  2591 discontinued; Attrib.syntax and Method.syntax have been adapted
  2592 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2593 attributes, methods, etc.
  2594 
  2595 * Pure: several functions of signature "... -> theory -> theory * ..."
  2596 have been reoriented to "... -> theory -> ... * theory" in order to
  2597 allow natural usage in combination with the ||>, ||>>, |-> and
  2598 fold_map combinators.
  2599 
  2600 * Pure: official theorem names (closed derivations) and additional
  2601 comments (tags) are now strictly separate.  Name hints -- which are
  2602 maintained as tags -- may be attached any time without affecting the
  2603 derivation.
  2604 
  2605 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2606 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2607 achieve the old behaviour.
  2608 
  2609 * Pure: the "Goal" constant is now called "prop", supporting a
  2610 slightly more general idea of ``protecting'' meta-level rule
  2611 statements.
  2612 
  2613 * Pure: Logic.(un)varify only works in a global context, which is now
  2614 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2615 Logic.legacy_(un)varify as temporary workaround.
  2616 
  2617 * Pure: structure Name provides scalable operations for generating
  2618 internal variable names, notably Name.variants etc.  This replaces
  2619 some popular functions from term.ML:
  2620 
  2621   Term.variant		->  Name.variant
  2622   Term.variantlist	->  Name.variant_list
  2623   Term.invent_names	->  Name.invent_list
  2624 
  2625 Note that low-level renaming rarely occurs in new code -- operations
  2626 from structure Variable are used instead (see below).
  2627 
  2628 * Pure: structure Variable provides fundamental operations for proper
  2629 treatment of fixed/schematic variables in a context.  For example,
  2630 Variable.import introduces fixes for schematics of given facts and
  2631 Variable.export reverses the effect (up to renaming) -- this replaces
  2632 various freeze_thaw operations.
  2633 
  2634 * Pure: structure Goal provides simple interfaces for
  2635 init/conclude/finish and tactical prove operations (replacing former
  2636 Tactic.prove).  Goal.prove is the canonical way to prove results
  2637 within a given context; Goal.prove_global is a degraded version for
  2638 theory level goals, including a global Drule.standard.  Note that
  2639 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2640 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2641 in a locale context).
  2642 
  2643 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2644 and type checking (Syntax.check_term etc.), with common combinations
  2645 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2646 which are considered legacy and await removal.
  2647 
  2648 * Pure/Syntax: generic interfaces for type unchecking
  2649 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2650 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2651 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2652 available for convenience, but refer to the very same operations using
  2653 a mere theory instead of a full context.
  2654 
  2655 * Isar: simplified treatment of user-level errors, using exception
  2656 ERROR of string uniformly.  Function error now merely raises ERROR,
  2657 without any side effect on output channels.  The Isar toplevel takes
  2658 care of proper display of ERROR exceptions.  ML code may use plain
  2659 handle/can/try; cat_error may be used to concatenate errors like this:
  2660 
  2661   ... handle ERROR msg => cat_error msg "..."
  2662 
  2663 Toplevel ML code (run directly or through the Isar toplevel) may be
  2664 embedded into the Isar toplevel with exception display/debug like
  2665 this:
  2666 
  2667   Isar.toplevel (fn () => ...)
  2668 
  2669 INCOMPATIBILITY, removed special transform_error facilities, removed
  2670 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2671 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2672 -- use plain ERROR instead.
  2673 
  2674 * Isar: theory setup now has type (theory -> theory), instead of a
  2675 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2676 
  2677 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2678 ProofContext.debug/verbose flags.
  2679 
  2680 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2681 theory before entering a proof state.  Transactions now always see a
  2682 quasi-functional intermediate checkpoint, both in interactive and
  2683 batch mode.
  2684 
  2685 * Isar: simplified interfaces for outer syntax.  Renamed
  2686 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2687 OuterSyntax.add_parsers -- this functionality is now included in
  2688 OuterSyntax.command etc.  INCOMPATIBILITY.
  2689 
  2690 * Simplifier: the simpset of a running simplification process now
  2691 contains a proof context (cf. Simplifier.the_context), which is the
  2692 very context that the initial simpset has been retrieved from (by
  2693 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2694 (solver, looper etc.) may depend on arbitrary proof data.
  2695 
  2696 * Simplifier.inherit_context inherits the proof context (plus the
  2697 local bounds) of the current simplification process; any simproc
  2698 etc. that calls the Simplifier recursively should do this!  Removed
  2699 former Simplifier.inherit_bounds, which is already included here --
  2700 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2701 specify an explicit context using Simplifier.context/theory_context.
  2702 
  2703 * Simplifier/Classical Reasoner: more abstract interfaces
  2704 change_simpset/claset for modifying the simpset/claset reference of a
  2705 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2706 INCOMPATIBILITY.
  2707 
  2708 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2709 "Trueprop" etc.
  2710 
  2711 
  2712 *** System ***
  2713 
  2714 * settings: the default heap location within ISABELLE_HOME_USER now
  2715 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2716 Isabelle installations.
  2717 
  2718 * isabelle-process: option -S (secure mode) disables some critical
  2719 operations, notably runtime compilation and evaluation of ML source
  2720 code.
  2721 
  2722 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2723 
  2724 * Support for parallel execution, using native multicore support of
  2725 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2726 independent theories, according to the given theory header
  2727 specifications. The maximum number of worker threads is specified via
  2728 usedir option -M or the "max-threads" setting in Proof General. A
  2729 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2730 to 6 on a 8-core machine.  User-code needs to observe certain
  2731 guidelines for thread-safe programming, see appendix A in the Isar
  2732 Implementation manual.
  2733 
  2734 
  2735 
  2736 New in Isabelle2005 (October 2005)
  2737 ----------------------------------
  2738 
  2739 *** General ***
  2740 
  2741 * Theory headers: the new header syntax for Isar theories is
  2742 
  2743   theory <name>
  2744   imports <theory1> ... <theoryN>
  2745   uses <file1> ... <fileM>
  2746   begin
  2747 
  2748 where the 'uses' part is optional.  The previous syntax
  2749 
  2750   theory <name> = <theory1> + ... + <theoryN>:
  2751 
  2752 will disappear in the next release.  Use isatool fixheaders to convert
  2753 existing theory files.  Note that there is no change in ancient
  2754 non-Isar theories now, but these will disappear soon.
  2755 
  2756 * Theory loader: parent theories can now also be referred to via
  2757 relative and absolute paths.
  2758 
  2759 * Command 'find_theorems' searches for a list of criteria instead of a
  2760 list of constants. Known criteria are: intro, elim, dest, name:string,
  2761 simp:term, and any term. Criteria can be preceded by '-' to select
  2762 theorems that do not match. Intro, elim, dest select theorems that
  2763 match the current goal, name:s selects theorems whose fully qualified
  2764 name contain s, and simp:term selects all simplification rules whose
  2765 lhs match term.  Any other term is interpreted as pattern and selects
  2766 all theorems matching the pattern. Available in ProofGeneral under
  2767 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2768 
  2769   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2770 
  2771 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2772 matching the current goal as introduction rule and not having "HOL."
  2773 in their name (i.e. not being defined in theory HOL).
  2774 
  2775 * Command 'thms_containing' has been discontinued in favour of
  2776 'find_theorems'; INCOMPATIBILITY.
  2777 
  2778 * Communication with Proof General is now 8bit clean, which means that
  2779 Unicode text in UTF-8 encoding may be used within theory texts (both
  2780 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2781 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2782 
  2783   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2784   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2785 
  2786 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2787 Classical Reasoner.  Typical big applications run around 2 times
  2788 faster.
  2789 
  2790 
  2791 *** Document preparation ***
  2792 
  2793 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2794 of raw sources.  Only those symbols that do not require additional
  2795 LaTeX packages (depending on comments in isabellesym.sty) are
  2796 displayed properly, everything else is left verbatim.  isatool display
  2797 and isatool print are used as front ends (these are subject to the
  2798 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2799 
  2800 * Command tags control specific markup of certain regions of text,
  2801 notably folding and hiding.  Predefined tags include "theory" (for
  2802 theory begin and end), "proof" for proof commands, and "ML" for
  2803 commands involving ML code; the additional tags "visible" and
  2804 "invisible" are unused by default.  Users may give explicit tag
  2805 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2806 interpretation of tags is determined by the LaTeX job during document
  2807 preparation: see option -V of isatool usedir, or options -n and -t of
  2808 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2809 \isadroptag.
  2810 
  2811 Several document versions may be produced at the same time via isatool
  2812 usedir (the generated index.html will link all of them).  Typical
  2813 specifications include ''-V document=theory,proof,ML'' to present
  2814 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2815 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2816 these parts without any formal replacement text.  The Isabelle site
  2817 default settings produce ''document'' and ''outline'' versions as
  2818 specified above.
  2819 
  2820 * Several new antiquotations:
  2821 
  2822   @{term_type term} prints a term with its type annotated;
  2823 
  2824   @{typeof term} prints the type of a term;
  2825 
  2826   @{const const} is the same as @{term const}, but checks that the
  2827   argument is a known logical constant;
  2828 
  2829   @{term_style style term} and @{thm_style style thm} print a term or
  2830   theorem applying a "style" to it
  2831 
  2832   @{ML text}
  2833 
  2834 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2835 definitions, equations, inequations etc., 'concl' printing only the
  2836 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2837 to print the specified premise.  TermStyle.add_style provides an ML
  2838 interface for introducing further styles.  See also the "LaTeX Sugar"
  2839 document practical applications.  The ML antiquotation prints
  2840 type-checked ML expressions verbatim.
  2841 
  2842 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2843 and 'text' support optional locale specification '(in loc)', which
  2844 specifies the default context for interpreting antiquotations.  For
  2845 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2846 
  2847 * Option 'locale=NAME' of antiquotations specifies an alternative
  2848 context interpreting the subsequent argument.  For example: @{thm
  2849 [locale=lattice] inf_assoc}.
  2850 
  2851 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2852 a proof context.
  2853 
  2854 * Proper output of antiquotations for theory commands involving a
  2855 proof context (such as 'locale' or 'theorem (in loc) ...').
  2856 
  2857 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2858 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2859 
  2860 * isatool usedir: new option -C (default true) controls whether option
  2861 -D should include a copy of the original document directory; -C false
  2862 prevents unwanted effects such as copying of administrative CVS data.
  2863 
  2864 
  2865 *** Pure ***
  2866 
  2867 * Considerably improved version of 'constdefs' command.  Now performs
  2868 automatic type-inference of declared constants; additional support for
  2869 local structure declarations (cf. locales and HOL records), see also
  2870 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2871 sequential dependencies of definitions within a single 'constdefs'
  2872 section; moreover, the declared name needs to be an identifier.  If
  2873 all fails, consider to fall back on 'consts' and 'defs' separately.
  2874 
  2875 * Improved indexed syntax and implicit structures.  First of all,
  2876 indexed syntax provides a notational device for subscripted
  2877 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2878 expressions.  Secondly, in a local context with structure
  2879 declarations, number indexes \<^sub>n or the empty index (default
  2880 number 1) refer to a certain fixed variable implicitly; option
  2881 show_structs controls printing of implicit structures.  Typical
  2882 applications of these concepts involve record types and locales.
  2883 
  2884 * New command 'no_syntax' removes grammar declarations (and
  2885 translations) resulting from the given syntax specification, which is
  2886 interpreted in the same manner as for the 'syntax' command.
  2887 
  2888 * 'Advanced' translation functions (parse_translation etc.) may depend
  2889 on the signature of the theory context being presently used for
  2890 parsing/printing, see also isar-ref manual.
  2891 
  2892 * Improved 'oracle' command provides a type-safe interface to turn an
  2893 ML expression of type theory -> T -> term into a primitive rule of
  2894 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2895 is already included here); see also FOL/ex/IffExample.thy;
  2896 INCOMPATIBILITY.
  2897 
  2898 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2899 before); "cI" is no longer bound, use "c.intro" instead.
  2900 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2901 axclasses vs. locales.
  2902 
  2903 * Improved internal renaming of symbolic identifiers -- attach primes
  2904 instead of base 26 numbers.
  2905 
  2906 * New flag show_question_marks controls printing of leading question
  2907 marks in schematic variable names.
  2908 
  2909 * In schematic variable names, *any* symbol following \<^isub> or
  2910 \<^isup> is now treated as part of the base name.  For example, the
  2911 following works without printing of awkward ".0" indexes:
  2912 
  2913   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2914     by simp
  2915 
  2916 * Inner syntax includes (*(*nested*) comments*).
  2917 
  2918 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2919 annotations as "(00...)".
  2920 
  2921 * Clear separation of logical types and nonterminals, where the latter
  2922 may only occur in 'syntax' specifications or type abbreviations.
  2923 Before that distinction was only partially implemented via type class
  2924 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2925 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2926 exotic syntax specifications may require further adaption
  2927 (e.g. Cube/Cube.thy).
  2928 
  2929 * Removed obsolete type class "logic", use the top sort {} instead.
  2930 Note that non-logical types should be declared as 'nonterminals'
  2931 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2932 specifications.
  2933 
  2934 * Attributes 'induct' and 'cases': type or set names may now be
  2935 locally fixed variables as well.
  2936 
  2937 * Simplifier: can now control the depth to which conditional rewriting
  2938 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2939 Limit.
  2940 
  2941 * Simplifier: simplification procedures may now take the current
  2942 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2943 interface), which is very useful for calling the Simplifier
  2944 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2945 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2946 low-level mk_simproc no longer applies Logic.varify internally, to
  2947 allow for use in a context of fixed variables.
  2948 
  2949 * thin_tac now works even if the assumption being deleted contains !!
  2950 or ==>.  More generally, erule now works even if the major premise of
  2951 the elimination rule contains !! or ==>.
  2952 
  2953 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2954 
  2955 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2956 from Pure, which contains all common declarations already.  Both
  2957 theories are defined via plain Isabelle/Isar .thy files.
  2958 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2959 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2960 use isatool fixcpure to adapt your theory and ML sources.
  2961 
  2962 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2963 selections of theorems in named facts via index ranges.
  2964 
  2965 * 'print_theorems': in theory mode, really print the difference
  2966 wrt. the last state (works for interactive theory development only),
  2967 in proof mode print all local facts (cf. 'print_facts');
  2968 
  2969 * 'hide': option '(open)' hides only base names.
  2970 
  2971 * More efficient treatment of intermediate checkpoints in interactive
  2972 theory development.
  2973 
  2974 * Code generator is now invoked via code_module (incremental code
  2975 generation) and code_library (modular code generation, ML structures
  2976 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2977 must be quoted when used as identifiers.
  2978 
  2979 * New 'value' command for reading, evaluating and printing terms using
  2980 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2981 quoted when used as identifier.
  2982 
  2983 
  2984 *** Locales ***
  2985 
  2986 * New commands for the interpretation of locale expressions in
  2987 theories (1), locales (2) and proof contexts (3).  These generate
  2988 proof obligations from the expression specification.  After the
  2989 obligations have been discharged, theorems of the expression are added
  2990 to the theory, target locale or proof context.  The synopsis of the
  2991 commands is a follows:
  2992 
  2993   (1) interpretation expr inst
  2994   (2) interpretation target < expr
  2995   (3) interpret expr inst
  2996 
  2997 Interpretation in theories and proof contexts require a parameter
  2998 instantiation of terms from the current context.  This is applied to
  2999 specifications and theorems of the interpreted expression.
  3000 Interpretation in locales only permits parameter renaming through the
  3001 locale expression.  Interpretation is smart in that interpretations
  3002 that are active already do not occur in proof obligations, neither are
  3003 instantiated theorems stored in duplicate.  Use 'print_interps' to
  3004 inspect active interpretations of a particular locale.  For details,
  3005 see the Isar Reference manual.  Examples can be found in
  3006 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  3007 
  3008 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  3009 'interpret' instead.
  3010 
  3011 * New context element 'constrains' for adding type constraints to
  3012 parameters.
  3013 
  3014 * Context expressions: renaming of parameters with syntax
  3015 redeclaration.
  3016 
  3017 * Locale declaration: 'includes' disallowed.
  3018 
  3019 * Proper static binding of attribute syntax -- i.e. types / terms /
  3020 facts mentioned as arguments are always those of the locale definition
  3021 context, independently of the context of later invocations.  Moreover,
  3022 locale operations (renaming and type / term instantiation) are applied
  3023 to attribute arguments as expected.
  3024 
  3025 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  3026 actual attributes; rare situations may require Attrib.attribute to
  3027 embed those attributes into Attrib.src that lack concrete syntax.
  3028 Attribute implementations need to cooperate properly with the static
  3029 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  3030 Attrib.XXX_thm etc. already do the right thing without further
  3031 intervention.  Only unusual applications -- such as "where" or "of"
  3032 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  3033 on the context and the facts involved -- may have to assign parsed
  3034 values to argument tokens explicitly.
  3035 
  3036 * Changed parameter management in theorem generation for long goal
  3037 statements with 'includes'.  INCOMPATIBILITY: produces a different
  3038 theorem statement in rare situations.
  3039 
  3040 * Locale inspection command 'print_locale' omits notes elements.  Use
  3041 'print_locale!' to have them included in the output.
  3042 
  3043 
  3044 *** Provers ***
  3045 
  3046 * Provers/hypsubst.ML: improved version of the subst method, for
  3047 single-step rewriting: it now works in bound variable contexts. New is
  3048 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  3049 rewrite a different subterm than the original subst method, which is
  3050 still available as 'simplesubst'.
  3051 
  3052 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  3053 and quasi orders.
  3054 
  3055 * Provers/trancl.ML: new transitivity reasoner for transitive and
  3056 reflexive-transitive closure of relations.
  3057 
  3058 * Provers/blast.ML: new reference depth_limit to make blast's depth
  3059 limit (previously hard-coded with a value of 20) user-definable.
  3060 
  3061 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  3062 is peformed already.  Object-logics merely need to finish their
  3063 initial simpset configuration as before.  INCOMPATIBILITY.
  3064 
  3065 
  3066 *** HOL ***
  3067 
  3068 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3069 
  3070   syntax (epsilon)
  3071     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3072 
  3073 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3074 and x-symbol; use option '-m epsilon' to get it actually printed.
  3075 Moreover, the mathematically important symbolic identifier \<epsilon>
  3076 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3077 
  3078 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3079 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3080 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3081 support corresponding Isar calculations.
  3082 
  3083 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3084 instead of ":".
  3085 
  3086 * theory SetInterval: changed the syntax for open intervals:
  3087 
  3088   Old       New
  3089   {..n(}    {..<n}
  3090   {)n..}    {n<..}
  3091   {m..n(}   {m..<n}
  3092   {)m..n}   {m<..n}
  3093   {)m..n(}  {m<..<n}
  3094 
  3095 The old syntax is still supported but will disappear in the next
  3096 release.  For conversion use the following Emacs search and replace
  3097 patterns (these are not perfect but work quite well):
  3098 
  3099   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3100   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3101 
  3102 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3103 equalities in commutative rings; method 'algebra' provides a generic
  3104 interface.
  3105 
  3106 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3107 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3108 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3109 be a tuple pattern.
  3110 
  3111 Some new syntax forms are available:
  3112 
  3113   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3114   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3115   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3116   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3117 
  3118 The latter form "\<Sum>x < k. e" used to be based on a separate
  3119 function "Summation", which has been discontinued.
  3120 
  3121 * theory Finite_Set: in structured induction proofs, the insert case
  3122 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3123 (insert F x)'.
  3124 
  3125 * The 'refute' command has been extended to support a much larger
  3126 fragment of HOL, including axiomatic type classes, constdefs and
  3127 typedefs, inductive datatypes and recursion.
  3128 
  3129 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3130 Requires zChaff with proof generation to be installed.  See
  3131 HOL/ex/SAT_Examples.thy for examples.
  3132 
  3133 * Datatype induction via method 'induct' now preserves the name of the
  3134 induction variable. For example, when proving P(xs::'a list) by
  3135 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3136 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3137 in unstructured proof scripts.
  3138 
  3139 * Reworked implementation of records.  Improved scalability for
  3140 records with many fields, avoiding performance problems for type
  3141 inference. Records are no longer composed of nested field types, but
  3142 of nested extension types. Therefore the record type only grows linear
  3143 in the number of extensions and not in the number of fields.  The
  3144 top-level (users) view on records is preserved.  Potential
  3145 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3146 old record representation. The type generated for a record is called
  3147 <record_name>_ext_type.
  3148 
  3149 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3150 proofs triggered by a record definition or a simproc (if
  3151 quick_and_dirty is enabled).  Definitions of large records can take
  3152 quite long.
  3153 
  3154 New simproc record_upd_simproc for simplification of multiple record
  3155 updates enabled by default.  Moreover, trivial updates are also
  3156 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3157 occasionally, since simplification is more powerful by default.
  3158 
  3159 * typedef: proper support for polymorphic sets, which contain extra
  3160 type-variables in the term.
  3161 
  3162 * Simplifier: automatically reasons about transitivity chains
  3163 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3164 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3165 old proofs break occasionally as simplification may now solve more
  3166 goals than previously.
  3167 
  3168 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3169 present.  Works for all partial orders (class "order"), in particular
  3170 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3171 just like y <= x.
  3172 
  3173 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3174 bound variable or a constant then the let is unfolded.  Otherwise
  3175 first a is simplified to b, and then f b is simplified to g. If
  3176 possible we abstract b from g arriving at "let x = b in h x",
  3177 otherwise we unfold the let and arrive at g.  The simproc can be
  3178 enabled/disabled by the reference use_let_simproc.  Potential
  3179 INCOMPATIBILITY since simplification is more powerful by default.
  3180 
  3181 * Classical reasoning: the meson method now accepts theorems as arguments.
  3182 
  3183 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3184 jobs to provide advice on the provability of subgoals.
  3185 
  3186 * Theory OrderedGroup and Ring_and_Field: various additions and
  3187 improvements to faciliate calculations involving equalities and
  3188 inequalities.
  3189 
  3190 The following theorems have been eliminated or modified
  3191 (INCOMPATIBILITY):
  3192 
  3193   abs_eq             now named abs_of_nonneg
  3194   abs_of_ge_0        now named abs_of_nonneg
  3195   abs_minus_eq       now named abs_of_nonpos
  3196   imp_abs_id         now named abs_of_nonneg
  3197   imp_abs_neg_id     now named abs_of_nonpos
  3198   mult_pos           now named mult_pos_pos
  3199   mult_pos_le        now named mult_nonneg_nonneg
  3200   mult_pos_neg_le    now named mult_nonneg_nonpos
  3201   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3202   mult_neg           now named mult_neg_neg
  3203   mult_neg_le        now named mult_nonpos_nonpos
  3204 
  3205 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3206      
  3207      zero_le_square
  3208      not_square_less_zero 
  3209 
  3210   The following lemmas have been deleted from Real/RealPow:
  3211   
  3212      realpow_zero_zero
  3213      realpow_two
  3214      realpow_less
  3215      zero_le_power
  3216      realpow_two_le
  3217      abs_realpow_two
  3218      realpow_two_abs     
  3219 
  3220 * Theory Parity: added rules for simplifying exponents.
  3221 
  3222 * Theory List:
  3223 
  3224 The following theorems have been eliminated or modified
  3225 (INCOMPATIBILITY):
  3226 
  3227   list_all_Nil       now named list_all.simps(1)
  3228   list_all_Cons      now named list_all.simps(2)
  3229   list_all_conv      now named list_all_iff
  3230   set_mem_eq         now named mem_iff
  3231 
  3232 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3233 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3234 
  3235 
  3236 *** HOL-Complex ***
  3237 
  3238 * Theory RealDef: better support for embedding natural numbers and
  3239 integers in the reals.
  3240 
  3241 The following theorems have been eliminated or modified
  3242 (INCOMPATIBILITY):
  3243 
  3244   exp_ge_add_one_self  now requires no hypotheses
  3245   real_of_int_add      reversed direction of equality (use [symmetric])
  3246   real_of_int_minus    reversed direction of equality (use [symmetric])
  3247   real_of_int_diff     reversed direction of equality (use [symmetric])
  3248   real_of_int_mult     reversed direction of equality (use [symmetric])
  3249 
  3250 * Theory RComplete: expanded support for floor and ceiling functions.
  3251 
  3252 * Theory Ln is new, with properties of the natural logarithm
  3253 
  3254 * Hyperreal: There is a new type constructor "star" for making
  3255 nonstandard types.  The old type names are now type synonyms:
  3256 
  3257   hypreal = real star
  3258   hypnat = nat star
  3259   hcomplex = complex star
  3260 
  3261 * Hyperreal: Many groups of similarly-defined constants have been
  3262 replaced by polymorphic versions (INCOMPATIBILITY):
  3263 
  3264   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3265 
  3266   starset      <-- starsetNat, starsetC
  3267   *s*          <-- *sNat*, *sc*
  3268   starset_n    <-- starsetNat_n, starsetC_n
  3269   *sn*         <-- *sNatn*, *scn*
  3270   InternalSets <-- InternalNatSets, InternalCSets
  3271 
  3272   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3273   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3274   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3275   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3276   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3277 
  3278 * Hyperreal: Many type-specific theorems have been removed in favor of
  3279 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3280 
  3281   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3282   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3283   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3284   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3285   right_minus <-- hypreal_add_minus
  3286   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3287   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3288   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3289   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3290   mult_1_right <-- hcomplex_mult_one_right
  3291   mult_zero_left <-- hcomplex_mult_zero_left
  3292   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3293   right_distrib <-- hypnat_add_mult_distrib2
  3294   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3295   right_inverse <-- hypreal_mult_inverse
  3296   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3297   order_refl <-- {hypreal,hypnat}_le_refl
  3298   order_trans <-- {hypreal,hypnat}_le_trans
  3299   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3300   order_less_le <-- {hypreal,hypnat}_less_le
  3301   linorder_linear <-- {hypreal,hypnat}_le_linear
  3302   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3303   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3304   add_nonneg_nonneg <-- hypreal_le_add_order
  3305 
  3306 * Hyperreal: Separate theorems having to do with type-specific
  3307 versions of constants have been merged into theorems that apply to the
  3308 new polymorphic constants (INCOMPATIBILITY):
  3309 
  3310   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3311   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3312   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3313   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3314   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3315   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3316   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3317   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3318   STAR_diff <-- {STAR,STARC}_diff
  3319   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3320     STARC_hcomplex_of_complex}_image_subset
  3321   starset_n_Un <-- starset{Nat,C}_n_Un
  3322   starset_n_Int <-- starset{Nat,C}_n_Int
  3323   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3324   starset_n_diff <-- starset{Nat,C}_n_diff
  3325   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3326   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3327   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3328   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3329   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3330   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3331   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3332   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3333   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3334   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3335   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3336   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3337   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3338   starfun_diff <-- starfun{C,RC,CR}_diff
  3339   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3340   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3341   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3342   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3343   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3344   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3345   starfun_Id <-- starfunC_Id
  3346   starfun_approx <-- starfun{Nat,CR}_approx
  3347   starfun_capprox <-- starfun{C,RC}_capprox
  3348   starfun_abs <-- starfunNat_rabs
  3349   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3350   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3351   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3352   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3353   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3354   starfun_add_approx <-- starfunCR_add_approx
  3355   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3356   starfun_divide <-- starfun{C,CR,RC}_divide
  3357   starfun_n <-- starfun{Nat,C}_n
  3358   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3359   starfun_n_add <-- starfun{Nat,C}_n_add
  3360   starfun_n_add_minus <-- starfunNat_n_add_minus
  3361   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3362   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3363   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3364 
  3365   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3366   star_n_minus <-- {hypreal,hcomplex}_minus
  3367   star_n_diff <-- {hypreal,hcomplex}_diff
  3368   star_n_mult <-- {hypreal,hcomplex}_mult
  3369   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3370   star_n_le <-- {hypreal,hypnat}_le
  3371   star_n_less <-- {hypreal,hypnat}_less
  3372   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3373   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3374   star_n_abs <-- hypreal_hrabs
  3375   star_n_divide <-- hcomplex_divide
  3376 
  3377   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3378   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3379   star_of_diff <-- hypreal_of_real_diff
  3380   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3381   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3382   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3383   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3384   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3385   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3386   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3387   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3388   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3389   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3390   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3391   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3392   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3393   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3394   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3395   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3396   star_of_power <-- hypreal_of_real_power
  3397   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3398 
  3399 * Hyperreal: new method "transfer" that implements the transfer
  3400 principle of nonstandard analysis. With a subgoal that mentions
  3401 nonstandard types like "'a star", the command "apply transfer"
  3402 replaces it with an equivalent one that mentions only standard types.
  3403 To be successful, all free variables must have standard types; non-
  3404 standard variables must have explicit universal quantifiers.
  3405 
  3406 * Hyperreal: A theory of Taylor series.
  3407 
  3408 
  3409 *** HOLCF ***
  3410 
  3411 * Discontinued special version of 'constdefs' (which used to support
  3412 continuous functions) in favor of the general Pure one with full
  3413 type-inference.
  3414 
  3415 * New simplification procedure for solving continuity conditions; it
  3416 is much faster on terms with many nested lambda abstractions (cubic
  3417 instead of exponential time).
  3418 
  3419 * New syntax for domain package: selector names are now optional.
  3420 Parentheses should be omitted unless argument is lazy, for example:
  3421 
  3422   domain 'a stream = cons "'a" (lazy "'a stream")
  3423 
  3424 * New command 'fixrec' for defining recursive functions with pattern
  3425 matching; defining multiple functions with mutual recursion is also
  3426 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3427 sinr, or any data constructor defined by the domain package. The given
  3428 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3429 syntax and examples.
  3430 
  3431 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3432 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3433 but the proof obligation additionally includes an admissibility
  3434 requirement. The packages generate instances of class cpo or pcpo,
  3435 with continuity and strictness theorems for Rep and Abs.
  3436 
  3437 * HOLCF: Many theorems have been renamed according to a more standard naming
  3438 scheme (INCOMPATIBILITY):
  3439 
  3440   foo_inject:  "foo$x = foo$y ==> x = y"
  3441   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3442   foo_less:    "(foo$x << foo$y) = (x << y)"
  3443   foo_strict:  "foo$UU = UU"
  3444   foo_defined: "... ==> foo$x ~= UU"
  3445   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3446 
  3447 
  3448 *** ZF ***
  3449 
  3450 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3451 including the First Isomorphism Theorem (on quotienting by the kernel
  3452 of a homomorphism).
  3453 
  3454 * ZF/Simplifier: install second copy of type solver that actually
  3455 makes use of TC rules declared to Isar proof contexts (or locales);
  3456 the old version is still required for ML proof scripts.
  3457 
  3458 
  3459 *** Cube ***
  3460 
  3461 * Converted to Isar theory format; use locales instead of axiomatic
  3462 theories.
  3463 
  3464 
  3465 *** ML ***
  3466 
  3467 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3468 for ||>, ||>>, |>>,
  3469 
  3470 * Pure/library.ML no longer defines its own option datatype, but uses
  3471 that of the SML basis, which has constructors NONE and SOME instead of
  3472 None and Some, as well as exception Option.Option instead of OPTION.
  3473 The functions the, if_none, is_some, is_none have been adapted
  3474 accordingly, while Option.map replaces apsome.
  3475 
  3476 * Pure/library.ML: the exception LIST has been given up in favour of
  3477 the standard exceptions Empty and Subscript, as well as
  3478 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3479 superceded by the standard hd and tl functions etc.
  3480 
  3481 A number of basic list functions are no longer exported to the ML
  3482 toplevel, as they are variants of predefined functions.  The following
  3483 suggests how one can translate existing code:
  3484 
  3485     rev_append xs ys = List.revAppend (xs, ys)
  3486     nth_elem (i, xs) = List.nth (xs, i)
  3487     last_elem xs = List.last xs
  3488     flat xss = List.concat xss
  3489     seq fs = List.app fs
  3490     partition P xs = List.partition P xs
  3491     mapfilter f xs = List.mapPartial f xs
  3492 
  3493 * Pure/library.ML: several combinators for linear functional
  3494 transformations, notably reverse application and composition:
  3495 
  3496   x |> f                f #> g
  3497   (x, y) |-> f          f #-> g
  3498 
  3499 * Pure/library.ML: introduced/changed precedence of infix operators:
  3500 
  3501   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3502   infix 2 ?;
  3503   infix 3 o oo ooo oooo;
  3504   infix 4 ~~ upto downto;
  3505 
  3506 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3507 infix operators.
  3508 
  3509 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3510 fold_map support linear functional transformations and nesting.  For
  3511 example:
  3512 
  3513   fold f [x1, ..., xN] y =
  3514     y |> f x1 |> ... |> f xN
  3515 
  3516   (fold o fold) f [xs1, ..., xsN] y =
  3517     y |> fold f xs1 |> ... |> fold f xsN
  3518 
  3519   fold f [x1, ..., xN] =
  3520     f x1 #> ... #> f xN
  3521 
  3522   (fold o fold) f [xs1, ..., xsN] =
  3523     fold f xs1 #> ... #> fold f xsN
  3524 
  3525 * Pure/library.ML: the following selectors on type 'a option are
  3526 available:
  3527 
  3528   the:               'a option -> 'a  (*partial*)
  3529   these:             'a option -> 'a  where 'a = 'b list
  3530   the_default: 'a -> 'a option -> 'a
  3531   the_list:          'a option -> 'a list
  3532 
  3533 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3534 basic operations for association lists, following natural argument
  3535 order; moreover the explicit equality predicate passed here avoids
  3536 potentially expensive polymorphic runtime equality checks.
  3537 The old functions may be expressed as follows:
  3538 
  3539   assoc = uncurry (AList.lookup (op =))
  3540   assocs = these oo AList.lookup (op =)
  3541   overwrite = uncurry (AList.update (op =)) o swap
  3542 
  3543 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3544 
  3545   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3546   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3547 
  3548 replacing make_keylist and keyfilter (occassionally used)
  3549 Naive rewrites:
  3550 
  3551   make_keylist = AList.make
  3552   keyfilter = AList.find (op =)
  3553 
  3554 * eq_fst and eq_snd now take explicit equality parameter, thus
  3555   avoiding eqtypes. Naive rewrites:
  3556 
  3557     eq_fst = eq_fst (op =)
  3558     eq_snd = eq_snd (op =)
  3559 
  3560 * Removed deprecated apl and apr (rarely used).
  3561   Naive rewrites:
  3562 
  3563     apl (n, op) =>>= curry op n
  3564     apr (op, m) =>>= fn n => op (n, m)
  3565 
  3566 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3567 provides a reasonably efficient light-weight implementation of sets as
  3568 lists.
  3569 
  3570 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3571 few new operations; existing lookup and update are now curried to
  3572 follow natural argument order (for use with fold etc.);
  3573 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3574 
  3575 * Pure/General: output via the Isabelle channels of
  3576 writeln/warning/error etc. is now passed through Output.output, with a
  3577 hook for arbitrary transformations depending on the print_mode
  3578 (cf. Output.add_mode -- the first active mode that provides a output
  3579 function wins).  Already formatted output may be embedded into further
  3580 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3581 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3582 accommodate easy composition of diagnostic messages etc.  Programmers
  3583 rarely need to care about Output.output or Output.raw at all, with
  3584 some notable exceptions: Output.output is required when bypassing the
  3585 standard channels (writeln etc.), or in token translations to produce
  3586 properly formatted results; Output.raw is required when capturing
  3587 already output material that will eventually be presented to the user
  3588 a second time.  For the default print mode, both Output.output and
  3589 Output.raw have no effect.
  3590 
  3591 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3592 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3593 cumulative results are displayed at the end of a batch session.
  3594 
  3595 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3596 replaced by File.platform_path and File.shell_path (with appropriate
  3597 hooks).  This provides a clean interface for unusual systems where the
  3598 internal and external process view of file names are different.
  3599 
  3600 * Pure: more efficient orders for basic syntactic entities: added
  3601 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3602 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3603 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3604 orders now -- potential INCOMPATIBILITY for code that depends on a
  3605 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3606 Library.sort_strings on result).
  3607 
  3608 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3609 fold_types traverse types/terms from left to right, observing natural
  3610 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3611 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3612 
  3613 * Pure: name spaces have been refined, with significant changes of the
  3614 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3615 to extern(_table).  The plain name entry path is superceded by a
  3616 general 'naming' context, which also includes the 'policy' to produce
  3617 a fully qualified name and external accesses of a fully qualified
  3618 name; NameSpace.extend is superceded by context dependent
  3619 Sign.declare_name.  Several theory and proof context operations modify
  3620 the naming context.  Especially note Theory.restore_naming and
  3621 ProofContext.restore_naming to get back to a sane state; note that
  3622 Theory.add_path is no longer sufficient to recover from
  3623 Theory.absolute_path in particular.
  3624 
  3625 * Pure: new flags short_names (default false) and unique_names
  3626 (default true) for controlling output of qualified names.  If
  3627 short_names is set, names are printed unqualified.  If unique_names is
  3628 reset, the name prefix is reduced to the minimum required to achieve
  3629 the original result when interning again, even if there is an overlap
  3630 with earlier declarations.
  3631 
  3632 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3633 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3634 (useful for printing error messages).  INCOMPATIBILITY.
  3635 
  3636 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3637 Theory.theory are now identified, referring to the universal
  3638 Context.theory (see Pure/context.ML).  Actual signature and theory
  3639 content is managed as theory data.  The old code and interfaces were
  3640 spread over many files and structures; the new arrangement introduces
  3641 considerable INCOMPATIBILITY to gain more clarity:
  3642 
  3643   Context -- theory management operations (name, identity, inclusion,
  3644     parents, ancestors, merge, etc.), plus generic theory data;
  3645 
  3646   Sign -- logical signature and syntax operations (declaring consts,
  3647     types, etc.), plus certify/read for common entities;
  3648 
  3649   Theory -- logical theory operations (stating axioms, definitions,
  3650     oracles), plus a copy of logical signature operations (consts,
  3651     types, etc.); also a few basic management operations (Theory.copy,
  3652     Theory.merge, etc.)
  3653 
  3654 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3655 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3656 for convenience -- they merely return the theory.
  3657 
  3658 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3659 
  3660 * Pure: the Isar proof context type is already defined early in Pure
  3661 as Context.proof (note that ProofContext.context and Proof.context are
  3662 aliases, where the latter is the preferred name).  This enables other
  3663 Isabelle components to refer to that type even before Isar is present.
  3664 
  3665 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3666 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3667 any of these kinds.  For example, Sign.intern typeK is now
  3668 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3669 Theory.hide_types.  Also note that former
  3670 Theory.hide_classes/types/consts are now
  3671 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3672 internalize their arguments!  INCOMPATIBILITY.
  3673 
  3674 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3675 datatype thmref (with constructors Name and NameSelection) instead of
  3676 plain string -- INCOMPATIBILITY;
  3677 
  3678 * Pure: cases produced by proof methods specify options, where NONE
  3679 means to remove case bindings -- INCOMPATIBILITY in
  3680 (RAW_)METHOD_CASES.
  3681 
  3682 * Pure: the following operations retrieve axioms or theorems from a
  3683 theory node or theory hierarchy, respectively:
  3684 
  3685   Theory.axioms_of: theory -> (string * term) list
  3686   Theory.all_axioms_of: theory -> (string * term) list
  3687   PureThy.thms_of: theory -> (string * thm) list
  3688   PureThy.all_thms_of: theory -> (string * thm) list
  3689 
  3690 * Pure: print_tac now outputs the goal through the trace channel.
  3691 
  3692 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3693 Reference Toplevel.debug (default false) controls detailed printing
  3694 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3695 controls execution profiling -- set to 1 for time and 2 for space
  3696 (both increase the runtime).
  3697 
  3698 * Isar session: The initial use of ROOT.ML is now always timed,
  3699 i.e. the log will show the actual process times, in contrast to the
  3700 elapsed wall-clock time that the outer shell wrapper produces.
  3701 
  3702 * Simplifier: improved handling of bound variables (nameless
  3703 representation, avoid allocating new strings).  Simprocs that invoke
  3704 the Simplifier recursively should use Simplifier.inherit_bounds to
  3705 avoid local name clashes.  Failure to do so produces warnings
  3706 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3707 for further details.
  3708 
  3709 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3710 bindings for all theorems stored within a given theory; this may help
  3711 in porting non-Isar theories to Isar ones, while keeping ML proof
  3712 scripts for the time being.
  3713 
  3714 * ML operator HTML.with_charset specifies the charset begin used for
  3715 generated HTML files.  For example:
  3716 
  3717   HTML.with_charset "utf-8" use_thy "Hebrew";
  3718   HTML.with_charset "utf-8" use_thy "Chinese";
  3719 
  3720 
  3721 *** System ***
  3722 
  3723 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3724 isabelle, isatool etc.).
  3725 
  3726 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3727 isatool doc, isatool mkdir, display_drafts etc.).
  3728 
  3729 * isatool usedir: option -f allows specification of the ML file to be
  3730 used by Isabelle; default is ROOT.ML.
  3731 
  3732 * New isatool version outputs the version identifier of the Isabelle
  3733 distribution being used.
  3734 
  3735 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3736 (containing Boolean satisfiability problems) into Isabelle/HOL
  3737 theories.
  3738 
  3739 
  3740 
  3741 New in Isabelle2004 (April 2004)
  3742 --------------------------------
  3743 
  3744 *** General ***
  3745 
  3746 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3747   Replaces linorder.ML.
  3748 
  3749 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3750   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3751   (\<a>...\<z>), are now considered normal letters, and can therefore
  3752   be used anywhere where an ASCII letter (a...zA...Z) has until
  3753   now. COMPATIBILITY: This obviously changes the parsing of some
  3754   terms, especially where a symbol has been used as a binder, say
  3755   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3756   as an identifier.  Fix it by inserting a space around former
  3757   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3758   existing theory and ML files.
  3759 
  3760 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3761 
  3762 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3763   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3764   a normal (but invisible) letter. For multiple letter subscripts repeat
  3765   \<^isub> like this: x\<^isub>1\<^isub>2.
  3766 
  3767 * Pure: There are now sub-/superscripts that can span more than one
  3768   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3769   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3770   superscript. The new control characters are not identifier parts.
  3771 
  3772 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3773   content of "..." to the latex file instead of \isacntrl... . The "..."
  3774   may consist of any printable characters excluding the end bracket >.
  3775 
  3776 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3777   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3778   declare constants "final", which prevents their being given a definition
  3779   later.  It is useful for constants whose behaviour is fixed axiomatically
  3780   rather than definitionally, such as the meta-logic connectives.
  3781 
  3782 * Pure: 'instance' now handles general arities with general sorts
  3783   (i.e. intersections of classes),
  3784 
  3785 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3786   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3787   It can be changed to alter the colors/layout of generated pages.
  3788 
  3789 
  3790 *** Isar ***
  3791 
  3792 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3793   cut_tac, subgoal_tac and thin_tac:
  3794   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3795     locales are no longer forced to write Isar proof scripts.
  3796     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3797     emulations.
  3798   - INCOMPATIBILITY: names of variables to be instantiated may no
  3799     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3800     This is consistent with the instantiation attribute "where".
  3801 
  3802 * Attributes "where" and "of":
  3803   - Now take type variables of instantiated theorem into account when reading
  3804     the instantiation string.  This fixes a bug that caused instantiated
  3805     theorems to have too special types in some circumstances.
  3806   - "where" permits explicit instantiations of type variables.
  3807 
  3808 * Calculation commands "moreover" and "also" no longer interfere with
  3809   current facts ("this"), admitting arbitrary combinations with "then"
  3810   and derived forms.
  3811 
  3812 * Locales:
  3813   - Goal statements involving the context element "includes" no longer
  3814     generate theorems with internal delta predicates (those ending on
  3815     "_axioms") in the premise.
  3816     Resolve particular premise with <locale>.intro to obtain old form.
  3817   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3818     specification and "includes" elements in goal statement.
  3819   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3820     [intro?] and [elim?] (respectively) by default.
  3821   - Experimental command for instantiation of locales in proof contexts:
  3822         instantiate <label>[<attrs>]: <loc>
  3823     Instantiates locale <loc> and adds all its theorems to the current context
  3824     taking into account their attributes.  Label and attrs are optional
  3825     modifiers, like in theorem declarations.  If present, names of
  3826     instantiated theorems are qualified with <label>, and the attributes
  3827     <attrs> are applied after any attributes these theorems might have already.
  3828       If the locale has assumptions, a chained fact of the form
  3829     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3830     are derived.  The command does not support old-style locales declared
  3831     with "locale (open)".
  3832       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3833 
  3834 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3835   (Isar) contexts.
  3836 
  3837 
  3838 *** HOL ***
  3839 
  3840 * Proof import: new image HOL4 contains the imported library from
  3841   the HOL4 system with about 2500 theorems. It is imported by
  3842   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3843   can be used like any other Isabelle image.  See
  3844   HOL/Import/HOL/README for more information.
  3845 
  3846 * Simplifier:
  3847   - Much improved handling of linear and partial orders.
  3848     Reasoners for linear and partial orders are set up for type classes
  3849     "linorder" and "order" respectively, and are added to the default simpset
  3850     as solvers.  This means that the simplifier can build transitivity chains
  3851     to solve goals from the assumptions.
  3852   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3853     of blast or auto after simplification become unnecessary because the goal
  3854     is solved by simplification already.
  3855 
  3856 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3857     all proved in axiomatic type classes for semirings, rings and fields.
  3858 
  3859 * Numerics:
  3860   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3861     now formalized using the Ring_and_Field theory mentioned above.
  3862   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3863     than before, because now they are set up once in a generic manner.
  3864   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3865     Look for the general versions in Ring_and_Field (and Power if they concern
  3866     exponentiation).
  3867 
  3868 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3869 
  3870 * Records:
  3871   - Record types are now by default printed with their type abbreviation
  3872     instead of the list of all field types. This can be configured via
  3873     the reference "print_record_type_abbr".
  3874   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3875     (not enabled by default).
  3876   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3877     EX x. x = sel r to True (not enabled by default).
  3878   - Tactic "record_split_simp_tac" to split and simplify records added.
  3879 
  3880 * 'specification' command added, allowing for definition by
  3881   specification.  There is also an 'ax_specification' command that
  3882   introduces the new constants axiomatically.
  3883 
  3884 * arith(_tac) is now able to generate counterexamples for reals as well.
  3885 
  3886 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3887 
  3888 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3889   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3890 
  3891 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3892   matrix theory to linear programming.
  3893 
  3894 * Unions and Intersections:
  3895   The latex output syntax of UN and INT has been changed
  3896   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3897   i.e. the index formulae has become a subscript.
  3898   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3899 
  3900 * Unions and Intersections over Intervals:
  3901   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3902   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3903   like in normal math, and corresponding versions for < and for intersection.
  3904 
  3905 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3906   lexicographic dictonary ordering has been added as "lexord".
  3907 
  3908 * ML: the legacy theory structures Int and List have been removed. They had
  3909   conflicted with ML Basis Library structures having the same names.
  3910 
  3911 * 'refute' command added to search for (finite) countermodels.  Only works
  3912   for a fragment of HOL.  The installation of an external SAT solver is
  3913   highly recommended.  See "HOL/Refute.thy" for details.
  3914 
  3915 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3916   formulae under an assignment of free variables to random values.
  3917   In contrast to 'refute', it can deal with inductive datatypes,
  3918   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3919   for examples.
  3920 
  3921 
  3922 *** HOLCF ***
  3923 
  3924 * Streams now come with concatenation and are part of the HOLCF image
  3925 
  3926 
  3927 
  3928 New in Isabelle2003 (May 2003)
  3929 ------------------------------
  3930 
  3931 *** General ***
  3932 
  3933 * Provers/simplifier:
  3934 
  3935   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3936     Assumptions are now subject to complete mutual simplification,
  3937     not just from left to right. The simplifier now preserves
  3938     the order of assumptions.
  3939 
  3940     Potential INCOMPATIBILITY:
  3941 
  3942     -- simp sometimes diverges where the old version did
  3943        not, e.g. invoking simp on the goal
  3944 
  3945         [| P (f x); y = x; f x = f y |] ==> Q
  3946 
  3947        now gives rise to the infinite reduction sequence
  3948 
  3949         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3950 
  3951        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3952        kind of problem.
  3953 
  3954     -- Tactics combining classical reasoner and simplification (such as auto)
  3955        are also affected by this change, because many of them rely on
  3956        simp. They may sometimes diverge as well or yield a different numbers
  3957        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3958        in case of problems. Sometimes subsequent calls to the classical
  3959        reasoner will fail because a preceeding call to the simplifier too
  3960        eagerly simplified the goal, e.g. deleted redundant premises.
  3961 
  3962   - The simplifier trace now shows the names of the applied rewrite rules
  3963 
  3964   - You can limit the number of recursive invocations of the simplifier
  3965     during conditional rewriting (where the simplifie tries to solve the
  3966     conditions before applying the rewrite rule):
  3967     ML "simp_depth_limit := n"
  3968     where n is an integer. Thus you can force termination where previously
  3969     the simplifier would diverge.
  3970 
  3971   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3972 
  3973   - No longer aborts on failed congruence proof.  Instead, the
  3974     congruence is ignored.
  3975 
  3976 * Pure: New generic framework for extracting programs from constructive
  3977   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3978   as HOL/Extraction for some case studies.
  3979 
  3980 * Pure: The main goal of the proof state is no longer shown by default, only
  3981 the subgoals. This behaviour is controlled by a new flag.
  3982    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3983 (ML: Proof.show_main_goal).
  3984 
  3985 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3986 rules whose conclusion matches subgoal 1:
  3987       PG menu: Isabelle/Isar -> Show me -> matching rules
  3988 The rules are ordered by how closely they match the subgoal.
  3989 In particular, rules that solve a subgoal outright are displayed first
  3990 (or rather last, the way they are printed).
  3991 (ML: ProofGeneral.print_intros())
  3992 
  3993 * Pure: New flag trace_unify_fail causes unification to print
  3994 diagnostic information (PG: in trace buffer) when it fails. This is
  3995 useful for figuring out why single step proofs like rule, erule or
  3996 assumption failed.
  3997 
  3998 * Pure: Locale specifications now produce predicate definitions
  3999 according to the body of text (covering assumptions modulo local
  4000 definitions); predicate "loc_axioms" covers newly introduced text,
  4001 while "loc" is cumulative wrt. all included locale expressions; the
  4002 latter view is presented only on export into the global theory
  4003 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  4004 on the old view without predicates;
  4005 
  4006 * Pure: predefined locales "var" and "struct" are useful for sharing
  4007 parameters (as in CASL, for example); just specify something like
  4008 ``var x + var y + struct M'' as import;
  4009 
  4010 * Pure: improved thms_containing: proper indexing of facts instead of
  4011 raw theorems; check validity of results wrt. current name space;
  4012 include local facts of proof configuration (also covers active
  4013 locales), cover fixed variables in index; may use "_" in term
  4014 specification; an optional limit for the number of printed facts may
  4015 be given (the default is 40);
  4016 
  4017 * Pure: disallow duplicate fact bindings within new-style theory files
  4018 (batch-mode only);
  4019 
  4020 * Provers: improved induct method: assumptions introduced by case
  4021 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  4022 the goal statement); "foo" still refers to all facts collectively;
  4023 
  4024 * Provers: the function blast.overloaded has been removed: all constants
  4025 are regarded as potentially overloaded, which improves robustness in exchange
  4026 for slight decrease in efficiency;
  4027 
  4028 * Provers/linorder: New generic prover for transitivity reasoning over
  4029 linear orders.  Note: this prover is not efficient!
  4030 
  4031 * Isar: preview of problems to finish 'show' now produce an error
  4032 rather than just a warning (in interactive mode);
  4033 
  4034 
  4035 *** HOL ***
  4036 
  4037 * arith(_tac)
  4038 
  4039  - Produces a counter example if it cannot prove a goal.
  4040    Note that the counter example may be spurious if the goal is not a formula
  4041    of quantifier-free linear arithmetic.
  4042    In ProofGeneral the counter example appears in the trace buffer.
  4043 
  4044  - Knows about div k and mod k where k is a numeral of type nat or int.
  4045 
  4046  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  4047    linear arithmetic fails. This takes account of quantifiers and divisibility.
  4048    Presburger arithmetic can also be called explicitly via presburger(_tac).
  4049 
  4050 * simp's arithmetic capabilities have been enhanced a bit: it now
  4051 takes ~= in premises into account (by performing a case split);
  4052 
  4053 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  4054 are distributed over a sum of terms;
  4055 
  4056 * New tactic "trans_tac" and method "trans" instantiate
  4057 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  4058 "<=", "<" and "=").
  4059 
  4060 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  4061 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  4062 
  4063 * 'typedef' command has new option "open" to suppress the set
  4064 definition;
  4065 
  4066 * functions Min and Max on finite sets have been introduced (theory
  4067 Finite_Set);
  4068 
  4069 * attribute [symmetric] now works for relations as well; it turns
  4070 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4071 
  4072 * induct over a !!-quantified statement (say !!x1..xn):
  4073   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4074 
  4075 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4076 %x. None. Warning: empty_def now refers to the previously hidden definition
  4077 of the empty set.
  4078 
  4079 * Algebra: formalization of classical algebra.  Intended as base for
  4080 any algebraic development in Isabelle.  Currently covers group theory
  4081 (up to Sylow's theorem) and ring theory (Universal Property of
  4082 Univariate Polynomials).  Contributions welcome;
  4083 
  4084 * GroupTheory: deleted, since its material has been moved to Algebra;
  4085 
  4086 * Complex: new directory of the complex numbers with numeric constants,
  4087 nonstandard complex numbers, and some complex analysis, standard and
  4088 nonstandard (Jacques Fleuriot);
  4089 
  4090 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4091 
  4092 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4093 Fleuriot);
  4094 
  4095 * Real/HahnBanach: updated and adapted to locales;
  4096 
  4097 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4098 Gray and Kramer);
  4099 
  4100 * UNITY: added the Meier-Sanders theory of progress sets;
  4101 
  4102 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4103 as abstract algorithms, instantiated to the JVM;
  4104 
  4105 * Bali: Java source language formalization. Type system, operational
  4106 semantics, axiomatic semantics. Supported language features:
  4107 classes, interfaces, objects,virtual methods, static methods,
  4108 static/instance fields, arrays, access modifiers, definite
  4109 assignment, exceptions.
  4110 
  4111 
  4112 *** ZF ***
  4113 
  4114 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4115 universe, etc.);
  4116 
  4117 * Main ZF: virtually all theories converted to new-style format;
  4118 
  4119 
  4120 *** ML ***
  4121 
  4122 * Pure: Tactic.prove provides sane interface for internal proofs;
  4123 omits the infamous "standard" operation, so this is more appropriate
  4124 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4125 
  4126 * Pure: improved error reporting of simprocs;
  4127 
  4128 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4129 up simprocs;
  4130 
  4131 
  4132 *** Document preparation ***
  4133 
  4134 * uses \par instead of \\ for line breaks in theory text. This may
  4135 shift some page breaks in large documents. To get the old behaviour
  4136 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4137 
  4138 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4139 other packages
  4140 
  4141 * \<euro> now needs package babel/greek instead of marvosym (which
  4142 broke \Rightarrow)
  4143 
  4144 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4145 textcomp package)
  4146 
  4147 
  4148 
  4149 New in Isabelle2002 (March 2002)
  4150 --------------------------------
  4151 
  4152 *** Document preparation ***
  4153 
  4154 * greatly simplified document preparation setup, including more
  4155 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4156 instructive isatool mkdir; users should basically be able to get
  4157 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4158 users may run a separate document processing stage manually like this:
  4159 "isatool usedir -D output HOL Test && isatool document Test/output";
  4160 
  4161 * theory dependency graph may now be incorporated into documents;
  4162 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4163 with \includegraphics of LaTeX;
  4164 
  4165 * proper spacing of consecutive markup elements, especially text
  4166 blocks after section headings;
  4167 
  4168 * support bold style (for single symbols only), input syntax is like
  4169 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4170 
  4171 * \<bullet> is now output as bold \cdot by default, which looks much
  4172 better in printed text;
  4173 
  4174 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4175 note that these symbols are currently unavailable in Proof General /
  4176 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4177 
  4178 * isatool latex no longer depends on changed TEXINPUTS, instead
  4179 isatool document copies the Isabelle style files to the target
  4180 location;
  4181 
  4182 
  4183 *** Isar ***
  4184 
  4185 * Pure/Provers: improved proof by cases and induction;
  4186   - 'case' command admits impromptu naming of parameters (such as
  4187     "case (Suc n)");
  4188   - 'induct' method divinates rule instantiation from the inductive
  4189     claim; no longer requires excessive ?P bindings for proper
  4190     instantiation of cases;
  4191   - 'induct' method properly enumerates all possibilities of set/type
  4192     rules; as a consequence facts may be also passed through *type*
  4193     rules without further ado;
  4194   - 'induct' method now derives symbolic cases from the *rulified*
  4195     rule (before it used to rulify cases stemming from the internal
  4196     atomized version); this means that the context of a non-atomic
  4197     statement becomes is included in the hypothesis, avoiding the
  4198     slightly cumbersome show "PROP ?case" form;
  4199   - 'induct' may now use elim-style induction rules without chaining
  4200     facts, using ``missing'' premises from the goal state; this allows
  4201     rules stemming from inductive sets to be applied in unstructured
  4202     scripts, while still benefitting from proper handling of non-atomic
  4203     statements; NB: major inductive premises need to be put first, all
  4204     the rest of the goal is passed through the induction;
  4205   - 'induct' proper support for mutual induction involving non-atomic
  4206     rule statements (uses the new concept of simultaneous goals, see
  4207     below);
  4208   - append all possible rule selections, but only use the first
  4209     success (no backtracking);
  4210   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4211   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4212   - added 'print_induct_rules' (covered by help item in recent Proof
  4213     General versions);
  4214   - moved induct/cases attributes to Pure, methods to Provers;
  4215   - generic method setup instantiated for FOL and HOL;
  4216 
  4217 * Pure: support multiple simultaneous goal statements, for example
  4218 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4219 meta-level mechanism, this acts as if several individual goals had
  4220 been stated separately; in particular common proof methods need to be
  4221 repeated in order to cover all claims; note that a single elimination
  4222 step is *not* sufficient to establish the two conjunctions, so this
  4223 fails:
  4224 
  4225   assume "A & B" then have A and B ..   (*".." fails*)
  4226 
  4227 better use "obtain" in situations as above; alternative refer to
  4228 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4229 
  4230 * Pure: proper integration with ``locales''; unlike the original
  4231 version by Florian Kammller, Isar locales package high-level proof
  4232 contexts rather than raw logical ones (e.g. we admit to include
  4233 attributes everywhere); operations on locales include merge and
  4234 rename; support for implicit arguments (``structures''); simultaneous
  4235 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4236 some examples;
  4237 
  4238 * Pure: the following commands have been ``localized'', supporting a
  4239 target locale specification "(in name)": 'lemma', 'theorem',
  4240 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4241 stored both within the locale and at the theory level (exported and
  4242 qualified by the locale name);
  4243 
  4244 * Pure: theory goals may now be specified in ``long'' form, with
  4245 ad-hoc contexts consisting of arbitrary locale elements. for example
  4246 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4247 definitions may be given, too); the result is a meta-level rule with
  4248 the context elements being discharged in the obvious way;
  4249 
  4250 * Pure: new proof command 'using' allows to augment currently used
  4251 facts after a goal statement ('using' is syntactically analogous to
  4252 'apply', but acts on the goal's facts only); this allows chained facts
  4253 to be separated into parts given before and after a claim, as in
  4254 ``from a and b have C using d and e <proof>'';
  4255 
  4256 * Pure: renamed "antecedent" case to "rule_context";
  4257 
  4258 * Pure: new 'judgment' command records explicit information about the
  4259 object-logic embedding (used by several tools internally); no longer
  4260 use hard-wired "Trueprop";
  4261 
  4262 * Pure: added 'corollary' command;
  4263 
  4264 * Pure: fixed 'token_translation' command;
  4265 
  4266 * Pure: removed obsolete 'exported' attribute;
  4267 
  4268 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4269 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4270 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4271 
  4272 * Pure: method 'atomize' presents local goal premises as object-level
  4273 statements (atomic meta-level propositions); setup controlled via
  4274 rewrite rules declarations of 'atomize' attribute; example
  4275 application: 'induct' method with proper rule statements in improper
  4276 proof *scripts*;
  4277 
  4278 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4279 now consider the syntactic context of assumptions, giving a better
  4280 chance to get type-inference of the arguments right (this is
  4281 especially important for locales);
  4282 
  4283 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4284 mode;
  4285 
  4286 * Pure/obtain: the formal conclusion "thesis", being marked as
  4287 ``internal'', may no longer be reference directly in the text;
  4288 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4289 situations;
  4290 
  4291 * Pure: generic 'sym' attribute which declares a rule both as pure
  4292 'elim?' and for the 'symmetric' operation;
  4293 
  4294 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4295 text; the fixed correlation with particular command syntax has been
  4296 discontinued;
  4297 
  4298 * Pure: new method 'rules' is particularly well-suited for proof
  4299 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4300 but often produces more compact proof terms with less detours;
  4301 
  4302 * Pure/Provers/classical: simplified integration with pure rule
  4303 attributes and methods; the classical "intro?/elim?/dest?"
  4304 declarations coincide with the pure ones; the "rule" method no longer
  4305 includes classically swapped intros; "intro" and "elim" methods no
  4306 longer pick rules from the context; also got rid of ML declarations
  4307 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4308 INCOMPATIBILITY;
  4309 
  4310 * Provers/classical: attribute 'swapped' produces classical inversions
  4311 of introduction rules;
  4312 
  4313 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4314 rules instead of full simplifier context; 'iff' attribute handles
  4315 conditional rules;
  4316 
  4317 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4318 
  4319 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4320 "(permissive)" option to recover old behavior;
  4321 
  4322 * HOL: 'inductive' no longer features separate (collective) attributes
  4323 for 'intros' (was found too confusing);
  4324 
  4325 * HOL: properly declared induction rules less_induct and
  4326 wf_induct_rule;
  4327 
  4328 
  4329 *** HOL ***
  4330 
  4331 * HOL: moved over to sane numeral syntax; the new policy is as
  4332 follows:
  4333 
  4334   - 0 and 1 are polymorphic constants, which are defined on any
  4335   numeric type (nat, int, real etc.);
  4336 
  4337   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4338   binary representation internally;
  4339 
  4340   - type nat has special constructor Suc, and generally prefers Suc 0
  4341   over 1::nat and Suc (Suc 0) over 2::nat;
  4342 
  4343 This change may cause significant problems of INCOMPATIBILITY; here
  4344 are some hints on converting existing sources:
  4345 
  4346   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4347   entities, so expressions involving "-" (unary or binary minus) need
  4348   to be spaced properly;
  4349 
  4350   - existing occurrences of "1" may need to be constraint "1::nat" or
  4351   even replaced by Suc 0; similar for old "2";
  4352 
  4353   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4354 
  4355   - remove all special provisions on numerals in proofs;
  4356 
  4357 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4358 representation (depends on bin_arith_simps in the default context);
  4359 
  4360 * HOL: symbolic syntax for x^2 (numeral 2);
  4361 
  4362 * HOL: the class of all HOL types is now called "type" rather than
  4363 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4364 in axclass/classes, instance/arities, and (usually rare) occurrences
  4365 in typings (of consts etc.); internally the class is called
  4366 "HOL.type", ML programs should refer to HOLogic.typeS;
  4367 
  4368 * HOL/record package improvements:
  4369   - new derived operations "fields" to build a partial record section,
  4370     "extend" to promote a fixed record to a record scheme, and
  4371     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4372     declared as simp by default;
  4373   - shared operations ("more", "fields", etc.) now need to be always
  4374     qualified) --- potential INCOMPATIBILITY;
  4375   - removed "make_scheme" operations (use "make" with "extend") --
  4376     INCOMPATIBILITY;
  4377   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4378   - provides cases/induct rules for use with corresponding Isar
  4379     methods (for concrete records, record schemes, concrete more
  4380     parts, and schematic more parts -- in that order);
  4381   - internal definitions directly based on a light-weight abstract
  4382     theory of product types over typedef rather than datatype;
  4383 
  4384 * HOL: generic code generator for generating executable ML code from
  4385 specifications; specific support for HOL constructs such as inductive
  4386 datatypes and sets, as well as recursive functions; can be invoked
  4387 via 'generate_code' theory section;
  4388 
  4389 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4390 
  4391 * HOL: consolidated and renamed several theories.  In particular:
  4392         Ord.thy has been absorbed into HOL.thy
  4393         String.thy has been absorbed into List.thy
  4394 
  4395 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4396 (beware of argument permutation!);
  4397 
  4398 * HOL: linorder_less_split superseded by linorder_cases;
  4399 
  4400 * HOL/List: "nodups" renamed to "distinct";
  4401 
  4402 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4403 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4404   - Ex_def has changed, now need to use some_eq_ex
  4405 
  4406 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4407 in this (rare) case use:
  4408 
  4409   delSWrapper "split_all_tac"
  4410   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4411 
  4412 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4413 MAY FAIL;
  4414 
  4415 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4416 Isabelle's type classes, ^ on functions and relations has too general
  4417 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4418 necessary to attach explicit type constraints;
  4419 
  4420 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4421 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4422 renamed accordingly (eg "compI" -> "rel_compI").
  4423 
  4424 * HOL: syntax translations now work properly with numerals and records
  4425 expressions;
  4426 
  4427 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4428 of "lam" -- INCOMPATIBILITY;
  4429 
  4430 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4431 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4432 renamed "Product_Type.unit";
  4433 
  4434 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4435 
  4436 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4437 the "cases" method);
  4438 
  4439 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4440 Florian Kammller);
  4441 
  4442 * HOL/IMP: updated and converted to new-style theory format; several
  4443 parts turned into readable document, with proper Isar proof texts and
  4444 some explanations (by Gerwin Klein);
  4445 
  4446 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4447 
  4448 * HOL-Hyperreal is now a logic image;
  4449 
  4450 
  4451 *** HOLCF ***
  4452 
  4453 * Isar: consts/constdefs supports mixfix syntax for continuous
  4454 operations;
  4455 
  4456 * Isar: domain package adapted to new-style theory format, e.g. see
  4457 HOLCF/ex/Dnat.thy;
  4458 
  4459 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4460 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4461 lift.induct_tac, always use UU instead of Undef;
  4462 
  4463 * HOLCF/IMP: updated and converted to new-style theory;
  4464 
  4465 
  4466 *** ZF ***
  4467 
  4468 * Isar: proper integration of logic-specific tools and packages,
  4469 including theory commands '(co)inductive', '(co)datatype',
  4470 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4471 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4472 
  4473 * theory Main no longer includes AC; for the Axiom of Choice, base
  4474 your theory on Main_ZFC;
  4475 
  4476 * the integer library now covers quotients and remainders, with many
  4477 laws relating division to addition, multiplication, etc.;
  4478 
  4479 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4480 typeless version of the formalism;
  4481 
  4482 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4483 format;
  4484 
  4485 * ZF/Induct: new directory for examples of inductive definitions,
  4486 including theory Multiset for multiset orderings; converted to
  4487 new-style theory format;
  4488 
  4489 * ZF: many new theorems about lists, ordinals, etc.;
  4490 
  4491 
  4492 *** General ***
  4493 
  4494 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4495 variable proof controls level of detail: 0 = no proofs (only oracle
  4496 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4497 also ref manual for further ML interfaces;
  4498 
  4499 * Pure/axclass: removed obsolete ML interface
  4500 goal_subclass/goal_arity;
  4501 
  4502 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4503 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4504 separate tokens, so expressions involving minus need to be spaced
  4505 properly;
  4506 
  4507 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4508 rather than "infixl" or "infixr";
  4509 
  4510 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4511 sort constraint specifications in type inference; e.g. "x::_::foo"
  4512 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4513 type variable);
  4514 
  4515 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4516 control output of nested => (types); the default behavior is
  4517 "type_brackets";
  4518 
  4519 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4520 tokens into AST constants;
  4521 
  4522 * Pure/syntax: prefer later declarations of translations and print
  4523 translation functions; potential INCOMPATIBILITY: need to reverse
  4524 multiple declarations for same syntax element constant;
  4525 
  4526 * Pure/show_hyps reset by default (in accordance to existing Isar
  4527 practice);
  4528 
  4529 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4530 addSafter;
  4531 
  4532 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4533 as well;
  4534 
  4535 * system: tested support for MacOS X; should be able to get Isabelle +
  4536 Proof General to work in a plain Terminal after installing Poly/ML
  4537 (e.g. from the Isabelle distribution area) and GNU bash alone
  4538 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4539 support requires further installations, e.g. from
  4540 http://fink.sourceforge.net/);
  4541 
  4542 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4543 
  4544 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4545 of 40 MB), cf. ML_OPTIONS;
  4546 
  4547 * system: Proof General keywords specification is now part of the
  4548 Isabelle distribution (see etc/isar-keywords.el);
  4549 
  4550 * system: support for persistent Proof General sessions (refrain from
  4551 outdating all loaded theories on startup); user may create writable
  4552 logic images like this: ``isabelle -q HOL Test'';
  4553 
  4554 * system: smart selection of Isabelle process versus Isabelle
  4555 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4556 run both "isabelle" and "Isabelle" even if file names are badly
  4557 damaged (executable inspects the case of the first letter of its own
  4558 name); added separate "isabelle-process" and "isabelle-interface";
  4559 
  4560 * system: refrain from any attempt at filtering input streams; no
  4561 longer support ``8bit'' encoding of old isabelle font, instead proper
  4562 iso-latin characters may now be used; the related isatools
  4563 "symbolinput" and "nonascii" have disappeared as well;
  4564 
  4565 * system: removed old "xterm" interface (the print modes "xterm" and
  4566 "xterm_color" are still available for direct use in a suitable
  4567 terminal);
  4568 
  4569 
  4570 
  4571 New in Isabelle99-2 (February 2001)
  4572 -----------------------------------
  4573 
  4574 *** Overview of INCOMPATIBILITIES ***
  4575 
  4576 * HOL: please note that theories in the Library and elsewhere often use the
  4577 new-style (Isar) format; to refer to their theorems in an ML script you must
  4578 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4579 
  4580 * HOL: inductive package no longer splits induction rule aggressively,
  4581 but only as far as specified by the introductions given; the old
  4582 format may be recovered via ML function complete_split_rule or attribute
  4583 'split_rule (complete)';
  4584 
  4585 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4586 gfp_Tarski to gfp_unfold;
  4587 
  4588 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4589 
  4590 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4591 relation); infix "^^" has been renamed "``"; infix "``" has been
  4592 renamed "`"; "univalent" has been renamed "single_valued";
  4593 
  4594 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4595 operation;
  4596 
  4597 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4598 
  4599 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4600 
  4601 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4602 consequence, it is no longer monotonic wrt. the local goal context
  4603 (which is now passed through the inductive cases);
  4604 
  4605 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4606 \<gg> to \<ggreater>;
  4607 
  4608 
  4609 *** Document preparation ***
  4610 
  4611 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4612 available: are "it" for near math-mode best-style output, "sl" for
  4613 slanted text style, and "tt" for plain type-writer; if no
  4614 \isabellestyle command is given, output is according to slanted
  4615 type-writer);
  4616 
  4617 * support sub/super scripts (for single symbols only), input syntax is
  4618 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4619 
  4620 * some more standard symbols; see Appendix A of the system manual for
  4621 the complete list of symbols defined in isabellesym.sty;
  4622 
  4623 * improved isabelle style files; more abstract symbol implementation
  4624 (should now use \isamath{...} and \isatext{...} in custom symbol
  4625 definitions);
  4626 
  4627 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4628 state; Note that presentation of goal states does not conform to
  4629 actual human-readable proof documents.  Please do not include goal
  4630 states into document output unless you really know what you are doing!
  4631 
  4632 * proper indentation of antiquoted output with proportional LaTeX
  4633 fonts;
  4634 
  4635 * no_document ML operator temporarily disables LaTeX document
  4636 generation;
  4637 
  4638 * isatool unsymbolize tunes sources for plain ASCII communication;
  4639 
  4640 
  4641 *** Isar ***
  4642 
  4643 * Pure: Isar now suffers initial goal statements to contain unbound
  4644 schematic variables (this does not conform to actual readable proof
  4645 documents, due to unpredictable outcome and non-compositional proof
  4646 checking); users who know what they are doing may use schematic goals
  4647 for Prolog-style synthesis of proven results;
  4648 
  4649 * Pure: assumption method (an implicit finishing) now handles actual
  4650 rules as well;
  4651 
  4652 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4653 initial goal, declare "that" only as Pure intro (only for single
  4654 steps); the "that" rule assumption may now be involved in implicit
  4655 finishing, thus ".." becomes a feasible for trivial obtains;
  4656 
  4657 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4658 instance proofs may be performed by "..";
  4659 
  4660 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4661 statements as well;
  4662 
  4663 * Pure: more robust selection of calculational rules;
  4664 
  4665 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4666 rule (as well as the assumption rule);
  4667 
  4668 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4669 lemmas, using the graph browser tool;
  4670 
  4671 * Pure: predict failure of "show" in interactive mode;
  4672 
  4673 * Pure: 'thms_containing' now takes actual terms as arguments;
  4674 
  4675 * HOL: improved method 'induct' --- now handles non-atomic goals
  4676 (potential INCOMPATIBILITY); tuned error handling;
  4677 
  4678 * HOL: cases and induct rules now provide explicit hints about the
  4679 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4680 any remaining facts are inserted into the goal verbatim;
  4681 
  4682 * HOL: local contexts (aka cases) may now contain term bindings as
  4683 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4684 the result to be shown in each case;
  4685 
  4686 * HOL: added 'recdef_tc' command;
  4687 
  4688 * isatool convert assists in eliminating legacy ML scripts;
  4689 
  4690 
  4691 *** HOL ***
  4692 
  4693 * HOL/Library: a collection of generic theories to be used together
  4694 with main HOL; the theory loader path already includes this directory
  4695 by default; the following existing theories have been moved here:
  4696 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4697 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4698 
  4699 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4700 modelling and verification task performed in Isabelle/HOL +
  4701 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4702 
  4703 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4704 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4705 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4706 'domain', this makes the theory consistent with mathematical
  4707 literature;
  4708 
  4709 * HOL basics: added overloaded operations "inverse" and "divide"
  4710 (infix "/"), syntax for generic "abs" operation, generic summation
  4711 operator \<Sum>;
  4712 
  4713 * HOL/typedef: simplified package, provide more useful rules (see also
  4714 HOL/subset.thy);
  4715 
  4716 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4717 now expressed as a proper nested rule (old-style tactic scripts may
  4718 require atomize_strip_tac to cope with non-atomic premises);
  4719 
  4720 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4721 to "split_conv" (old name still available for compatibility);
  4722 
  4723 * HOL: improved concrete syntax for strings (e.g. allows translation
  4724 rules with string literals);
  4725 
  4726 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4727  and Fleuriot's mechanization of analysis, including the transcendental
  4728  functions for the reals;
  4729 
  4730 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4731 
  4732 
  4733 *** CTT ***
  4734 
  4735 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4736 "lam" is displayed as TWO lambda-symbols
  4737 
  4738 * CTT: theory Main now available, containing everything (that is, Bool
  4739 and Arith);
  4740 
  4741 
  4742 *** General ***
  4743 
  4744 * Pure: the Simplifier has been implemented properly as a derived rule
  4745 outside of the actual kernel (at last!); the overall performance
  4746 penalty in practical applications is about 50%, while reliability of
  4747 the Isabelle inference kernel has been greatly improved;
  4748 
  4749 * print modes "brackets" and "no_brackets" control output of nested =>
  4750 (types) and ==> (props); the default behaviour is "brackets";
  4751 
  4752 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4753 as assumptions as well;
  4754 
  4755 * system: support Poly/ML 4.0;
  4756 
  4757 * system: isatool install handles KDE version 1 or 2;
  4758 
  4759 
  4760 
  4761 New in Isabelle99-1 (October 2000)
  4762 ----------------------------------
  4763 
  4764 *** Overview of INCOMPATIBILITIES ***
  4765 
  4766 * HOL: simplification of natural numbers is much changed; to partly
  4767 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4768 issue the following ML commands:
  4769 
  4770   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4771   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4772 
  4773 * HOL: simplification no longer dives into case-expressions; this is
  4774 controlled by "t.weak_case_cong" for each datatype t;
  4775 
  4776 * HOL: nat_less_induct renamed to less_induct;
  4777 
  4778 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4779 fixsome to patch .thy and .ML sources automatically;
  4780 
  4781   select_equality  -> some_equality
  4782   select_eq_Ex     -> some_eq_ex
  4783   selectI2EX       -> someI2_ex
  4784   selectI2         -> someI2
  4785   selectI          -> someI
  4786   select1_equality -> some1_equality
  4787   Eps_sym_eq       -> some_sym_eq_trivial
  4788   Eps_eq           -> some_eq_trivial
  4789 
  4790 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4791 
  4792 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4793 instead);
  4794 
  4795 * HOL: the recursion equations generated by 'recdef' are now called
  4796 f.simps instead of f.rules;
  4797 
  4798 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4799 
  4800 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4801 sometimes be needed;
  4802 
  4803 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4804 
  4805 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4806 
  4807 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4808 product is now "<*>" instead of "Times"; the lexicographic product is
  4809 now "<*lex*>" instead of "**";
  4810 
  4811 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4812 of main HOL, but was unused); better use HOL's datatype package;
  4813 
  4814 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4815 the old syntax may be recovered as follows:
  4816 
  4817   syntax (symbols)
  4818     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4819       (infixl "\\<oplus>" 100)
  4820 
  4821 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4822 
  4823 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4824 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4825 internally;
  4826 
  4827 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4828 changed from A/r to A//r;
  4829 
  4830 * ZF: new treatment of arithmetic (nat & int) may break some old
  4831 proofs;
  4832 
  4833 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4834 rulify -> rule_format, elimify -> elim_format, ...);
  4835 
  4836 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4837 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4838 should have to change intro!! to intro? only); replaced "delrule" by
  4839 "rule del";
  4840 
  4841 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4842 
  4843 * Provers: strengthened force_tac by using new first_best_tac;
  4844 
  4845 * LaTeX document preparation: several changes of isabelle.sty (see
  4846 lib/texinputs);
  4847 
  4848 
  4849 *** Document preparation ***
  4850 
  4851 * formal comments (text blocks etc.) in new-style theories may now
  4852 contain antiquotations of thm/prop/term/typ/text to be presented
  4853 according to latex print mode; concrete syntax is like this:
  4854 @{term[show_types] "f(x) = a + x"};
  4855 
  4856 * isatool mkdir provides easy setup of Isabelle session directories,
  4857 including proper document sources;
  4858 
  4859 * generated LaTeX sources are now deleted after successful run
  4860 (isatool document -c); may retain a copy somewhere else via -D option
  4861 of isatool usedir;
  4862 
  4863 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4864 style files, achieving self-contained LaTeX sources and simplifying
  4865 LaTeX debugging;
  4866 
  4867 * old-style theories now produce (crude) LaTeX output as well;
  4868 
  4869 * browser info session directories are now self-contained (may be put
  4870 on WWW server seperately); improved graphs of nested sessions; removed
  4871 graph for 'all sessions';
  4872 
  4873 * several improvements in isabelle style files; \isabellestyle{it}
  4874 produces fake math mode output; \isamarkupheader is now \section by
  4875 default; see lib/texinputs/isabelle.sty etc.;
  4876 
  4877 
  4878 *** Isar ***
  4879 
  4880 * Isar/Pure: local results and corresponding term bindings are now
  4881 subject to Hindley-Milner polymorphism (similar to ML); this
  4882 accommodates incremental type-inference very nicely;
  4883 
  4884 * Isar/Pure: new derived language element 'obtain' supports
  4885 generalized existence reasoning;
  4886 
  4887 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4888 support accumulation of results, without applying any rules yet;
  4889 useful to collect intermediate results without explicit name
  4890 references, and for use with transitivity rules with more than 2
  4891 premises;
  4892 
  4893 * Isar/Pure: scalable support for case-analysis type proofs: new
  4894 'case' language element refers to local contexts symbolically, as
  4895 produced by certain proof methods; internally, case names are attached
  4896 to theorems as "tags";
  4897 
  4898 * Isar/Pure: theory command 'hide' removes declarations from
  4899 class/type/const name spaces;
  4900 
  4901 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4902 indicate potential overloading;
  4903 
  4904 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4905 
  4906 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4907 "{a,b,c}" instead of {a,b,c};
  4908 
  4909 * Isar/Pure now provides its own version of intro/elim/dest
  4910 attributes; useful for building new logics, but beware of confusion
  4911 with the version in Provers/classical;
  4912 
  4913 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4914 case name 'antecedent';
  4915 
  4916 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4917 to the current context is now done automatically);
  4918 
  4919 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4920 for definining proof methods in ML;
  4921 
  4922 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4923 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4924 most cases, one should have to change intro!! to intro? only);
  4925 replaced "delrule" by "rule del";
  4926 
  4927 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4928 'symmetric' attribute (the latter supercedes [RS sym]);
  4929 
  4930 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4931 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4932 well (including splits);
  4933 
  4934 * Isar/Provers: Simplifier and Classical methods now support all kind
  4935 of modifiers used in the past, including 'cong', 'iff', etc.
  4936 
  4937 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4938 of Simplifier and Classical reasoner);
  4939 
  4940 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4941 now support named cases; major packages (inductive, datatype, primrec,
  4942 recdef) support case names and properly name parameters;
  4943 
  4944 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4945 monotonicity conditions are extracted to be proven at end of
  4946 calculations;
  4947 
  4948 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4949 method anyway;
  4950 
  4951 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4952 split_if split_if_asm; datatype package provides theorems foo.splits =
  4953 foo.split foo.split_asm for each datatype;
  4954 
  4955 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4956 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4957 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4958 use "(cases (simplified))" method in proper proof texts);
  4959 
  4960 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4961 
  4962 * Isar: names of theorems etc. may be natural numbers as well;
  4963 
  4964 * Isar: 'pr' command: optional arguments for goals_limit and
  4965 ProofContext.prems_limit; no longer prints theory contexts, but only
  4966 proof states;
  4967 
  4968 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4969 additional print modes to be specified; e.g. "pr(latex)" will print
  4970 proof state according to the Isabelle LaTeX style;
  4971 
  4972 * Isar: improved support for emulating tactic scripts, including proof
  4973 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4974 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4975 (for HOL datatypes);
  4976 
  4977 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4978 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4979 'proof method scripts' have to be in depth-first order;
  4980 
  4981 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4982 
  4983 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4984 should instead use individual commands for printing items
  4985 (print_commands, print_methods etc.);
  4986 
  4987 * Isar: added 'nothing' --- the empty list of theorems;
  4988 
  4989 
  4990 *** HOL ***
  4991 
  4992 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4993 corresponding virtual machine and a specification of its bytecode
  4994 verifier and a lightweight bytecode verifier, including proofs of
  4995 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4996 Cornelia Pusch (see also the homepage of project Bali at
  4997 http://isabelle.in.tum.de/Bali/);
  4998 
  4999 * HOL/Algebra: new theory of rings and univariate polynomials, by
  5000 Clemens Ballarin;
  5001 
  5002 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  5003 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  5004 Rasmussen;
  5005 
  5006 * HOL/Lattice: fundamental concepts of lattice theory and order
  5007 structures, including duals, properties of bounds versus algebraic
  5008 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  5009 Theorem for complete lattices etc.; may also serve as a demonstration
  5010 for abstract algebraic reasoning using axiomatic type classes, and
  5011 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  5012 
  5013 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  5014 von Oheimb;
  5015 
  5016 * HOL/IMPP: extension of IMP with local variables and mutually
  5017 recursive procedures, by David von Oheimb;
  5018 
  5019 * HOL/Lambda: converted into new-style theory and document;
  5020 
  5021 * HOL/ex/Multiquote: example of multiple nested quotations and
  5022 anti-quotations -- basically a generalized version of de-Bruijn
  5023 representation; very useful in avoiding lifting of operations;
  5024 
  5025 * HOL/record: added general record equality rule to simpset; fixed
  5026 select-update simplification procedure to handle extended records as
  5027 well; admit "r" as field name;
  5028 
  5029 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  5030 other numeric types and also as the identity of groups, rings, etc.;
  5031 
  5032 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  5033 Types nat and int belong to this axclass;
  5034 
  5035 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  5036    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  5037    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  5038   two terms #m*u and #n*u are replaced by #(m+n)*u
  5039     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  5040   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  5041     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  5042 
  5043 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  5044 powerful prover for predicate logic but knows nothing of clasets; see
  5045 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  5046 
  5047 * HOL: new version of "case_tac" subsumes both boolean case split and
  5048 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  5049 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  5050 
  5051 * HOL: simplification no longer dives into case-expressions: only the
  5052 selector expression is simplified, but not the remaining arms; to
  5053 enable full simplification of case-expressions for datatype t, you may
  5054 remove t.weak_case_cong from the simpset, either globally (Delcongs
  5055 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  5056 
  5057 * HOL/recdef: the recursion equations generated by 'recdef' for
  5058 function 'f' are now called f.simps instead of f.rules; if all
  5059 termination conditions are proved automatically, these simplification
  5060 rules are added to the simpset, as in primrec; rules may be named
  5061 individually as well, resulting in a separate list of theorems for
  5062 each equation;
  5063 
  5064 * HOL/While is a new theory that provides a while-combinator. It
  5065 permits the definition of tail-recursive functions without the
  5066 provision of a termination measure. The latter is necessary once the
  5067 invariant proof rule for while is applied.
  5068 
  5069 * HOL: new (overloaded) notation for the set of elements below/above
  5070 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5071 
  5072 * HOL: theorems impI, allI, ballI bound as "strip";
  5073 
  5074 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5075 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5076 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5077 
  5078 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5079 
  5080 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5081 main HOL, but was unused);
  5082 
  5083 * HOL: fewer consts declared as global (e.g. have to refer to
  5084 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5085 
  5086 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5087 in case of overlap with user translations (e.g. judgements over
  5088 tuples); (note that the underlying logical represenation is still
  5089 bogus);
  5090 
  5091 
  5092 *** ZF ***
  5093 
  5094 * ZF: simplification automatically cancels common terms in arithmetic
  5095 expressions over nat and int;
  5096 
  5097 * ZF: new treatment of nat to minimize type-checking: all operators
  5098 coerce their operands to a natural number using the function natify,
  5099 making the algebraic laws unconditional;
  5100 
  5101 * ZF: as above, for int: operators coerce their operands to an integer
  5102 using the function intify;
  5103 
  5104 * ZF: the integer library now contains many of the usual laws for the
  5105 orderings, including $<=, and monotonicity laws for $+ and $*;
  5106 
  5107 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5108 simplification;
  5109 
  5110 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5111 to the simplifier and classical reasoner simultaneously;
  5112 
  5113 
  5114 *** General ***
  5115 
  5116 * Provers: blast_tac now handles actual object-logic rules as
  5117 assumptions; note that auto_tac uses blast_tac internally as well;
  5118 
  5119 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5120 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5121 
  5122 * Provers: delrules now handles destruct rules as well (no longer need
  5123 explicit make_elim);
  5124 
  5125 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5126   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5127 use instead the strong form,
  5128   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5129 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5130 from destruct-rules;
  5131 
  5132 * Provers: Simplifier.easy_setup provides a fast path to basic
  5133 Simplifier setup for new object-logics;
  5134 
  5135 * Pure: AST translation rules no longer require constant head on LHS;
  5136 
  5137 * Pure: improved name spaces: ambiguous output is qualified; support
  5138 for hiding of names;
  5139 
  5140 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5141 XSYMBOL_HOME; no longer need to do manual configuration in most
  5142 situations;
  5143 
  5144 * system: compression of ML heaps images may now be controlled via -c
  5145 option of isabelle and isatool usedir (currently only observed by
  5146 Poly/ML);
  5147 
  5148 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5149 useful for remote X11);
  5150 
  5151 * system: provide TAGS file for Isabelle sources;
  5152 
  5153 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5154 order;
  5155 
  5156 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5157 timing flag supersedes proof_timing and Toplevel.trace;
  5158 
  5159 * ML: new combinators |>> and |>>> for incremental transformations
  5160 with secondary results (e.g. certain theory extensions):
  5161 
  5162 * ML: PureThy.add_defs gets additional argument to indicate potential
  5163 overloading (usually false);
  5164 
  5165 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5166 results;
  5167 
  5168 
  5169 
  5170 New in Isabelle99 (October 1999)
  5171 --------------------------------
  5172 
  5173 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5174 
  5175 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5176 are no longer simplified.  (This allows the simplifier to unfold recursive
  5177 functional programs.)  To restore the old behaviour, declare
  5178 
  5179     Delcongs [if_weak_cong];
  5180 
  5181 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5182 complement;
  5183 
  5184 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5185 
  5186 * HOL/datatype: mutual_induct_tac no longer exists --
  5187   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5188 
  5189 * HOL/typedef: fixed type inference for representing set; type
  5190 arguments now have to occur explicitly on the rhs as type constraints;
  5191 
  5192 * ZF: The con_defs part of an inductive definition may no longer refer
  5193 to constants declared in the same theory;
  5194 
  5195 * HOL, ZF: the function mk_cases, generated by the inductive
  5196 definition package, has lost an argument.  To simplify its result, it
  5197 uses the default simpset instead of a supplied list of theorems.
  5198 
  5199 * HOL/List: the constructors of type list are now Nil and Cons;
  5200 
  5201 * Simplifier: the type of the infix ML functions
  5202         setSSolver addSSolver setSolver addSolver
  5203 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5204 for packaging solvers. A solver is created via
  5205         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5206 where the string argument is only a comment.
  5207 
  5208 
  5209 *** Proof tools ***
  5210 
  5211 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5212 decision procedure for linear arithmetic. Currently it is used for
  5213 types `nat', `int', and `real' in HOL (see below); it can, should and
  5214 will be instantiated for other types and logics as well.
  5215 
  5216 * The simplifier now accepts rewrite rules with flexible heads, eg
  5217      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5218   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5219   matching.
  5220 
  5221 
  5222 *** General ***
  5223 
  5224 * New Isabelle/Isar subsystem provides an alternative to traditional
  5225 tactical theorem proving; together with the ProofGeneral/isar user
  5226 interface it offers an interactive environment for developing human
  5227 readable proof documents (Isar == Intelligible semi-automated
  5228 reasoning); for further information see isatool doc isar-ref,
  5229 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5230 
  5231 * improved and simplified presentation of theories: better HTML markup
  5232 (including colors), graph views in several sizes; isatool usedir now
  5233 provides a proper interface for user theories (via -P option); actual
  5234 document preparation based on (PDF)LaTeX is available as well (for
  5235 new-style theories only); see isatool doc system for more information;
  5236 
  5237 * native support for Proof General, both for classic Isabelle and
  5238 Isabelle/Isar;
  5239 
  5240 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5241 using the graph browser tool;
  5242 
  5243 * Isabelle manuals now also available as PDF;
  5244 
  5245 * theory loader rewritten from scratch (may not be fully
  5246 bug-compatible); old loadpath variable has been replaced by show_path,
  5247 add_path, del_path, reset_path functions; new operations such as
  5248 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5249 isatool doc ref);
  5250 
  5251 * improved isatool install: option -k creates KDE application icon,
  5252 option -p DIR installs standalone binaries;
  5253 
  5254 * added ML_PLATFORM setting (useful for cross-platform installations);
  5255 more robust handling of platform specific ML images for SML/NJ;
  5256 
  5257 * the settings environment is now statically scoped, i.e. it is never
  5258 created again in sub-processes invoked from isabelle, isatool, or
  5259 Isabelle;
  5260 
  5261 * path element specification '~~' refers to '$ISABELLE_HOME';
  5262 
  5263 * in locales, the "assumes" and "defines" parts may be omitted if
  5264 empty;
  5265 
  5266 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5267 long arrows);
  5268 
  5269 * new print_mode "HTML";
  5270 
  5271 * new flag show_tags controls display of tags of theorems (which are
  5272 basically just comments that may be attached by some tools);
  5273 
  5274 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5275 mode and goal output format:
  5276 
  5277 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5278 244c244
  5279 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5280 ---
  5281 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5282 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5283 181c181
  5284 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5285 ---
  5286 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5287 
  5288 * function bind_thms stores lists of theorems (cf. bind_thm);
  5289 
  5290 * new shorthand tactics ftac, eatac, datac, fatac;
  5291 
  5292 * qed (and friends) now accept "" as result name; in that case the
  5293 theorem is not stored, but proper checks and presentation of the
  5294 result still apply;
  5295 
  5296 * theorem database now also indexes constants "Trueprop", "all",
  5297 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5298 
  5299 
  5300 *** HOL ***
  5301 
  5302 ** HOL arithmetic **
  5303 
  5304 * There are now decision procedures for linear arithmetic over nat and
  5305 int:
  5306 
  5307 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5308 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5309 are treated as atomic; subformulae not involving type `nat' or `int'
  5310 are ignored; quantified subformulae are ignored unless they are
  5311 positive universal or negative existential. The tactic has to be
  5312 invoked by hand and can be a little bit slow. In particular, the
  5313 running time is exponential in the number of occurrences of `min' and
  5314 `max', and `-' on `nat'.
  5315 
  5316 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5317 (negated) (in)equalities among the premises and the conclusion into
  5318 account (i.e. no compound formulae) and does not know about `min' and
  5319 `max', and `-' on `nat'. It is fast and is used automatically by the
  5320 simplifier.
  5321 
  5322 NB: At the moment, these decision procedures do not cope with mixed
  5323 nat/int formulae where the two parts interact, such as `m < n ==>
  5324 int(m) < int(n)'.
  5325 
  5326 * HOL/Numeral provides a generic theory of numerals (encoded
  5327 efficiently as bit strings); setup for types nat/int/real is in place;
  5328 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5329 int, existing theories and proof scripts may require a few additional
  5330 type constraints;
  5331 
  5332 * integer division and remainder can now be performed on constant
  5333 arguments;
  5334 
  5335 * many properties of integer multiplication, division and remainder
  5336 are now available;
  5337 
  5338 * An interface to the Stanford Validity Checker (SVC) is available through the
  5339 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5340 are proved automatically.  SVC must be installed separately, and its results
  5341 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5342 invocation of the underlying oracle).  For SVC see
  5343   http://verify.stanford.edu/SVC
  5344 
  5345 * IsaMakefile: the HOL-Real target now builds an actual image;
  5346 
  5347 
  5348 ** HOL misc **
  5349 
  5350 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5351 (in Isabelle/Isar) -- by Gertrud Bauer;
  5352 
  5353 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5354 analysis for assembly languages with subtypes;
  5355 
  5356 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5357 -- avoids syntactic ambiguities and treats state, transition, and
  5358 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5359 changed syntax and (many) tactics;
  5360 
  5361 * HOL/inductive: Now also handles more general introduction rules such
  5362   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5363   theorems are now maintained within the theory (maintained via the
  5364   "mono" attribute);
  5365 
  5366 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5367   (using function types) such as
  5368 
  5369   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5370 
  5371 * HOL/record: record_simproc (part of the default simpset) takes care
  5372 of selectors applied to updated records; record_split_tac is no longer
  5373 part of the default claset; update_defs may now be removed from the
  5374 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5375 
  5376   claset_ref () := claset() addSWrapper record_split_wrapper;
  5377   Delsimprocs [record_simproc]
  5378 
  5379 * HOL/typedef: fixed type inference for representing set; type
  5380 arguments now have to occur explicitly on the rhs as type constraints;
  5381 
  5382 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5383 names rather than an ML expression;
  5384 
  5385 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5386 supplied later.  Program schemes can be defined, such as
  5387     "While B C s = (if B s then While B C (C s) else s)"
  5388 where the well-founded relation can be chosen after B and C have been given.
  5389 
  5390 * HOL/List: the constructors of type list are now Nil and Cons;
  5391 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5392 course, ML tools referring to List.list.op # etc. have to be adapted;
  5393 
  5394 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5395 disabled by default; run isabelle with option -m HOL to get back to
  5396 the original Gordon/HOL-style output;
  5397 
  5398 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5399 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5400 
  5401 * HOL basic syntax simplified (more orthogonal): all variants of
  5402 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5403 Eps operator is provided as well: "SOME x. P[x]";
  5404 
  5405 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5406 
  5407 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5408 thus available for user theories;
  5409 
  5410 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5411 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5412 time;
  5413 
  5414 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5415 several times and then mp;
  5416 
  5417 
  5418 *** LK ***
  5419 
  5420 * the notation <<...>> is now available as a notation for sequences of
  5421 formulas;
  5422 
  5423 * the simplifier is now installed
  5424 
  5425 * the axiom system has been generalized (thanks to Soren Heilmann)
  5426 
  5427 * the classical reasoner now has a default rule database
  5428 
  5429 
  5430 *** ZF ***
  5431 
  5432 * new primrec section allows primitive recursive functions to be given
  5433 directly (as in HOL) over datatypes and the natural numbers;
  5434 
  5435 * new tactics induct_tac and exhaust_tac for induction (or case
  5436 analysis) over datatypes and the natural numbers;
  5437 
  5438 * the datatype declaration of type T now defines the recursor T_rec;
  5439 
  5440 * simplification automatically does freeness reasoning for datatype
  5441 constructors;
  5442 
  5443 * automatic type-inference, with AddTCs command to insert new
  5444 type-checking rules;
  5445 
  5446 * datatype introduction rules are now added as Safe Introduction rules
  5447 to the claset;
  5448 
  5449 * the syntax "if P then x else y" is now available in addition to
  5450 if(P,x,y);
  5451 
  5452 
  5453 *** Internal programming interfaces ***
  5454 
  5455 * tuned simplifier trace output; new flag debug_simp;
  5456 
  5457 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5458 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5459 
  5460 * AxClass.axclass_tac lost the theory argument;
  5461 
  5462 * tuned current_goals_markers semantics: begin / end goal avoids
  5463 printing empty lines;
  5464 
  5465 * removed prs and prs_fn hook, which was broken because it did not
  5466 include \n in its semantics, forcing writeln to add one
  5467 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5468 string -> unit if you really want to output text without newline;
  5469 
  5470 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5471 plain output, interface builders may have to enable 'isabelle_font'
  5472 mode to get Isabelle font glyphs as before;
  5473 
  5474 * refined token_translation interface; INCOMPATIBILITY: output length
  5475 now of type real instead of int;
  5476 
  5477 * theory loader actions may be traced via new ThyInfo.add_hook
  5478 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5479 your own database of information attached to *whole* theories -- as
  5480 opposed to intra-theory data slots offered via TheoryDataFun;
  5481 
  5482 * proper handling of dangling sort hypotheses (at last!);
  5483 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5484 extra sort hypotheses that can be witnessed from the type signature;
  5485 the force_strip_shyps flag is gone, any remaining shyps are simply
  5486 left in the theorem (with a warning issued by strip_shyps_warning);
  5487 
  5488 
  5489 
  5490 New in Isabelle98-1 (October 1998)
  5491 ----------------------------------
  5492 
  5493 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5494 
  5495 * several changes of automated proof tools;
  5496 
  5497 * HOL: major changes to the inductive and datatype packages, including
  5498 some minor incompatibilities of theory syntax;
  5499 
  5500 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5501 called `inj_on';
  5502 
  5503 * HOL: removed duplicate thms in Arith:
  5504   less_imp_add_less  should be replaced by  trans_less_add1
  5505   le_imp_add_le      should be replaced by  trans_le_add1
  5506 
  5507 * HOL: unary minus is now overloaded (new type constraints may be
  5508 required);
  5509 
  5510 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5511 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5512 now taken as an integer constant.
  5513 
  5514 * Pure: ML function 'theory_of' renamed to 'theory';
  5515 
  5516 
  5517 *** Proof tools ***
  5518 
  5519 * Simplifier:
  5520   1. Asm_full_simp_tac is now more aggressive.
  5521      1. It will sometimes reorient premises if that increases their power to
  5522         simplify.
  5523      2. It does no longer proceed strictly from left to right but may also
  5524         rotate premises to achieve further simplification.
  5525      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5526      old Asm_full_simp_tac in that it does not rotate premises.
  5527   2. The simplifier now knows a little bit about nat-arithmetic.
  5528 
  5529 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5530 allows for selected deletion of wrappers, by introduction of names for
  5531 wrapper functionals.  This implies that addbefore, addSbefore,
  5532 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5533 and that adding two tactics with the same name overwrites the first
  5534 one (emitting a warning).
  5535   type wrapper = (int -> tactic) -> (int -> tactic)
  5536   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5537   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5538   delWrapper, delSWrapper: claset *  string            -> claset
  5539   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5540 
  5541 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5542 semantics; addbefore now affects only the unsafe part of step_tac
  5543 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5544 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5545 by Force_tac;
  5546 
  5547 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5548 compWrapper; added safe wrapper (and access functions for it);
  5549 
  5550 * HOL/split_all_tac is now much faster and fails if there is nothing
  5551 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5552 and the names of the automatically generated variables have changed.
  5553 split_all_tac has moved within claset() from unsafe wrappers to safe
  5554 wrappers, which means that !!-bound variables are split much more
  5555 aggressively, and safe_tac and clarify_tac now split such variables.
  5556 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5557 Note: the same holds for record_split_tac, which does the job of
  5558 split_all_tac for record fields.
  5559 
  5560 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5561 permanently to the default simpset using Addsplits just like
  5562 Addsimps. They can be removed via Delsplits just like
  5563 Delsimps. Lower-case versions are also available.
  5564 
  5565 * HOL/Simplifier: The rule split_if is now part of the default
  5566 simpset. This means that the simplifier will eliminate all occurrences
  5567 of if-then-else in the conclusion of a goal. To prevent this, you can
  5568 either remove split_if completely from the default simpset by
  5569 `Delsplits [split_if]' or remove it in a specific call of the
  5570 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5571 other case splitting rules to/from the default simpset: every datatype
  5572 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5573 t is the name of the datatype).
  5574 
  5575 * Classical reasoner / Simplifier combination: new force_tac (and
  5576 derivatives Force_tac, force) combines rewriting and classical
  5577 reasoning (and whatever other tools) similarly to auto_tac, but is
  5578 aimed to solve the given subgoal completely.
  5579 
  5580 
  5581 *** General ***
  5582 
  5583 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5584 and `goalw': the theory is no longer needed as an explicit argument -
  5585 the current theory context is used; assumptions are no longer returned
  5586 at the ML-level unless one of them starts with ==> or !!; it is
  5587 recommended to convert to these new commands using isatool fixgoal
  5588 (backup your sources first!);
  5589 
  5590 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5591 the current theory context, and 'theory' to lookup stored theories;
  5592 
  5593 * new theory section 'locale' for declaring constants, assumptions and
  5594 definitions that have local scope;
  5595 
  5596 * new theory section 'nonterminals' for purely syntactic types;
  5597 
  5598 * new theory section 'setup' for generic ML setup functions
  5599 (e.g. package initialization);
  5600 
  5601 * the distribution now includes Isabelle icons: see
  5602 lib/logo/isabelle-{small,tiny}.xpm;
  5603 
  5604 * isatool install - install binaries with absolute references to
  5605 ISABELLE_HOME/bin;
  5606 
  5607 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5608 
  5609 * print mode 'emacs' reserved for Isamode;
  5610 
  5611 * support multiple print (ast) translations per constant name;
  5612 
  5613 * theorems involving oracles are now printed with a suffixed [!];
  5614 
  5615 
  5616 *** HOL ***
  5617 
  5618 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5619 
  5620 * HOL/inductive package reorganized and improved: now supports mutual
  5621 definitions such as
  5622 
  5623   inductive EVEN ODD
  5624     intrs
  5625       null "0 : EVEN"
  5626       oddI "n : EVEN ==> Suc n : ODD"
  5627       evenI "n : ODD ==> Suc n : EVEN"
  5628 
  5629 new theorem list "elims" contains an elimination rule for each of the
  5630 recursive sets; inductive definitions now handle disjunctive premises
  5631 correctly (also ZF);
  5632 
  5633 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5634 "mutual_induct" no longer exists - the induction rule is always
  5635 contained in "induct";
  5636 
  5637 
  5638 * HOL/datatype package re-implemented and greatly improved: now
  5639 supports mutually recursive datatypes such as
  5640 
  5641   datatype
  5642     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5643             | SUM ('a aexp) ('a aexp)
  5644             | DIFF ('a aexp) ('a aexp)
  5645             | NUM 'a
  5646   and
  5647     'a bexp = LESS ('a aexp) ('a aexp)
  5648             | AND ('a bexp) ('a bexp)
  5649             | OR ('a bexp) ('a bexp)
  5650 
  5651 as well as indirectly recursive datatypes such as
  5652 
  5653   datatype
  5654     ('a, 'b) term = Var 'a
  5655                   | App 'b ((('a, 'b) term) list)
  5656 
  5657 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5658 induction on mutually / indirectly recursive datatypes.
  5659 
  5660 Primrec equations are now stored in theory and can be accessed via
  5661 <function_name>.simps.
  5662 
  5663 INCOMPATIBILITIES:
  5664 
  5665   - Theories using datatypes must now have theory Datatype as an
  5666     ancestor.
  5667   - The specific <typename>.induct_tac no longer exists - use the
  5668     generic induct_tac instead.
  5669   - natE has been renamed to nat.exhaust - use exhaust_tac
  5670     instead of res_inst_tac ... natE. Note that the variable
  5671     names in nat.exhaust differ from the names in natE, this
  5672     may cause some "fragile" proofs to fail.
  5673   - The theorems split_<typename>_case and split_<typename>_case_asm
  5674     have been renamed to <typename>.split and <typename>.split_asm.
  5675   - Since default sorts of type variables are now handled correctly,
  5676     some datatype definitions may have to be annotated with explicit
  5677     sort constraints.
  5678   - Primrec definitions no longer require function name and type
  5679     of recursive argument.
  5680 
  5681 Consider using isatool fixdatatype to adapt your theories and proof
  5682 scripts to the new package (backup your sources first!).
  5683 
  5684 
  5685 * HOL/record package: considerably improved implementation; now
  5686 includes concrete syntax for record types, terms, updates; theorems
  5687 for surjective pairing and splitting !!-bound record variables; proof
  5688 support is as follows:
  5689 
  5690   1) standard conversions (selectors or updates applied to record
  5691 constructor terms) are part of the standard simpset;
  5692 
  5693   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5694 made part of standard simpset and claset via addIffs;
  5695 
  5696   3) a tactic for record field splitting (record_split_tac) is part of
  5697 the standard claset (addSWrapper);
  5698 
  5699 To get a better idea about these rules you may retrieve them via
  5700 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5701 the name of your record type.
  5702 
  5703 The split tactic 3) conceptually simplifies by the following rule:
  5704 
  5705   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5706 
  5707 Thus any record variable that is bound by meta-all will automatically
  5708 blow up into some record constructor term, consequently the
  5709 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5710 solve record problems automatically.
  5711 
  5712 
  5713 * reorganized the main HOL image: HOL/Integ and String loaded by
  5714 default; theory Main includes everything;
  5715 
  5716 * automatic simplification of integer sums and comparisons, using cancellation;
  5717 
  5718 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5719 
  5720 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5721 
  5722 * many new identities for unions, intersections, set difference, etc.;
  5723 
  5724 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5725 called split_if, split_split, split_sum_case and split_nat_case (to go
  5726 with add/delsplits);
  5727 
  5728 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5729 (?x::unit) = (); this is made part of the default simpset, which COULD
  5730 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5731 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5732 unit_abs_eta_conv is added in order to counter the effect of
  5733 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5734 %u.f();
  5735 
  5736 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5737 makes more sense);
  5738 
  5739 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5740   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5741   disjointness reasoning but breaking a few old proofs.
  5742 
  5743 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5744 to 'converse' from 'inverse' (for compatibility with ZF and some
  5745 literature);
  5746 
  5747 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5748 the well-founded relation;
  5749 
  5750 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5751     Compl A.  The "Compl" syntax remains available as input syntax for this
  5752     release ONLY.
  5753 
  5754 * HOL/Update: new theory of function updates:
  5755     f(a:=b) == %x. if x=a then b else f x
  5756 may also be iterated as in f(a:=b,c:=d,...);
  5757 
  5758 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5759 
  5760 * HOL/List:
  5761   - new function list_update written xs[i:=v] that updates the i-th
  5762     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5763   - new function `upt' written [i..j(] which generates the list
  5764     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5765     bound write [i..j], which is a shorthand for [i..j+1(].
  5766   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5767 
  5768 * HOL/Arith:
  5769   - removed 'pred' (predecessor) function;
  5770   - generalized some theorems about n-1;
  5771   - many new laws about "div" and "mod";
  5772   - new laws about greatest common divisors (see theory ex/Primes);
  5773 
  5774 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5775 instead of "inverse";
  5776 
  5777 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5778   of the multiset ordering;
  5779 
  5780 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5781   (not included by default);
  5782 
  5783 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5784 
  5785 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5786   programs, i.e. different program variables may have different types.
  5787 
  5788 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5789   [previously, this check worked only if the rewrite rule was unconditional]
  5790   Now rew can involve either definitions or equalities (either == or =).
  5791 
  5792 
  5793 *** ZF ***
  5794 
  5795 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5796   only the theorems proved on ZF.ML;
  5797 
  5798 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5799   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5800   disjointness reasoning but breaking a few old proofs.
  5801 
  5802 * ZF/Update: new theory of function updates
  5803     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5804   may also be iterated as in f(a:=b,c:=d,...);
  5805 
  5806 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5807 
  5808 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5809   [previously, this check worked only if the rewrite rule was unconditional]
  5810   Now rew can involve either definitions or equalities (either == or =).
  5811 
  5812 * case_tac provided for compatibility with HOL
  5813     (like the old excluded_middle_tac, but with subgoals swapped)
  5814 
  5815 
  5816 *** Internal programming interfaces ***
  5817 
  5818 * Pure: several new basic modules made available for general use, see
  5819 also src/Pure/README;
  5820 
  5821 * improved the theory data mechanism to support encapsulation (data
  5822 kind name replaced by private Object.kind, acting as authorization
  5823 key); new type-safe user interface via functor TheoryDataFun; generic
  5824 print_data function becomes basically useless;
  5825 
  5826 * removed global_names compatibility flag -- all theory declarations
  5827 are qualified by default;
  5828 
  5829 * module Pure/Syntax now offers quote / antiquote translation
  5830 functions (useful for Hoare logic etc. with implicit dependencies);
  5831 see HOL/ex/Antiquote for an example use;
  5832 
  5833 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5834 cterm -> thm;
  5835 
  5836 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5837 subgoal;
  5838 
  5839 * Display.print_goals function moved to Locale.print_goals;
  5840 
  5841 * standard print function for goals supports current_goals_markers
  5842 variable for marking begin of proof, end of proof, start of goal; the
  5843 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5844 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5845 for example;
  5846 
  5847 
  5848 
  5849 New in Isabelle98 (January 1998)
  5850 --------------------------------
  5851 
  5852 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5853 
  5854 * changed lexical syntax of terms / types: dots made part of long
  5855 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5856 
  5857 * simpset (and claset) reference variable replaced by functions
  5858 simpset / simpset_ref;
  5859 
  5860 * no longer supports theory aliases (via merge) and non-trivial
  5861 implicit merge of thms' signatures;
  5862 
  5863 * most internal names of constants changed due to qualified names;
  5864 
  5865 * changed Pure/Sequence interface (see Pure/seq.ML);
  5866 
  5867 
  5868 *** General Changes ***
  5869 
  5870 * hierachically structured name spaces (for consts, types, axms, thms
  5871 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5872 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5873 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5874 long_names for fully qualified output names; NOTE: ML programs
  5875 (special tactics, packages etc.) referring to internal names may have
  5876 to be adapted to cope with fully qualified names; in case of severe
  5877 backward campatibility problems try setting 'global_names' at compile
  5878 time to have enrything declared within a flat name space; one may also
  5879 fine tune name declarations in theories via the 'global' and 'local'
  5880 section;
  5881 
  5882 * reimplemented the implicit simpset and claset using the new anytype
  5883 data filed in signatures; references simpset:simpset ref etc. are
  5884 replaced by functions simpset:unit->simpset and
  5885 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5886 to patch your ML files accordingly;
  5887 
  5888 * HTML output now includes theory graph data for display with Java
  5889 applet or isatool browser; data generated automatically via isatool
  5890 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5891 
  5892 * defs may now be conditional; improved rewrite_goals_tac to handle
  5893 conditional equations;
  5894 
  5895 * defs now admits additional type arguments, using TYPE('a) syntax;
  5896 
  5897 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5898 creates a new theory node; implicit merge of thms' signatures is
  5899 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5900 transfer:theory->thm->thm in (rare) cases;
  5901 
  5902 * improved handling of draft signatures / theories; draft thms (and
  5903 ctyps, cterms) are automatically promoted to real ones;
  5904 
  5905 * slightly changed interfaces for oracles: admit many per theory, named
  5906 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5907 
  5908 * print_goals: optional output of const types (set show_consts and
  5909 show_types);
  5910 
  5911 * improved output of warnings (###) and errors (***);
  5912 
  5913 * subgoal_tac displays a warning if the new subgoal has type variables;
  5914 
  5915 * removed old README and Makefiles;
  5916 
  5917 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5918 
  5919 * removed obsolete init_pps and init_database;
  5920 
  5921 * deleted the obsolete tactical STATE, which was declared by
  5922     fun STATE tacfun st = tacfun st st;
  5923 
  5924 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5925 (which abbreviates $HOME);
  5926 
  5927 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5928 use isatool fixseq to adapt your ML programs (this works for fully
  5929 qualified references to the Sequence structure only!);
  5930 
  5931 * use_thy no longer requires writable current directory; it always
  5932 reloads .ML *and* .thy file, if either one is out of date;
  5933 
  5934 
  5935 *** Classical Reasoner ***
  5936 
  5937 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5938 tactics that use classical reasoning to simplify a subgoal without
  5939 splitting it into several subgoals;
  5940 
  5941 * Safe_tac: like safe_tac but uses the default claset;
  5942 
  5943 
  5944 *** Simplifier ***
  5945 
  5946 * added simplification meta rules:
  5947     (asm_)(full_)simplify: simpset -> thm -> thm;
  5948 
  5949 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5950 logics (again);
  5951 
  5952 * added prems argument to simplification procedures;
  5953 
  5954 * HOL, FOL, ZF: added infix function `addsplits':
  5955   instead of `<simpset> setloop (split_tac <thms>)'
  5956   you can simply write `<simpset> addsplits <thms>'
  5957 
  5958 
  5959 *** Syntax ***
  5960 
  5961 * TYPE('a) syntax for type reflection terms;
  5962 
  5963 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5964 
  5965 * pretty printer: changed order of mixfix annotation preference (again!);
  5966 
  5967 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5968 
  5969 
  5970 *** HOL ***
  5971 
  5972 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5973   with `addloop' of the simplifier to faciliate case splitting in premises.
  5974 
  5975 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5976 
  5977 * HOL/Auth: new protocol proofs including some for the Internet
  5978   protocol TLS;
  5979 
  5980 * HOL/Map: new theory of `maps' a la VDM;
  5981 
  5982 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5983 cancelling out common nat summands from =, <, <= (in)equalities, or
  5984 differences; simplification procedures nat_cancel_factor for
  5985 cancelling common factor from =, <, <= (in)equalities over natural
  5986 sums; nat_cancel contains both kinds of procedures, it is installed by
  5987 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5988 
  5989 * HOL/simplifier: terms of the form
  5990   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5991   are rewritten to
  5992   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5993   and those of the form
  5994   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5995   are rewritten to
  5996   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5997 
  5998 * HOL/datatype
  5999   Each datatype `t' now comes with a theorem `split_t_case' of the form
  6000 
  6001   P(t_case f1 ... fn x) =
  6002      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  6003         ...
  6004        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  6005      )
  6006 
  6007   and a theorem `split_t_case_asm' of the form
  6008 
  6009   P(t_case f1 ... fn x) =
  6010     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  6011         ...
  6012        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  6013      )
  6014   which can be added to a simpset via `addsplits'. The existing theorems
  6015   expand_list_case and expand_option_case have been renamed to
  6016   split_list_case and split_option_case.
  6017 
  6018 * HOL/Arithmetic:
  6019   - `pred n' is automatically converted to `n-1'.
  6020     Users are strongly encouraged not to use `pred' any longer,
  6021     because it will disappear altogether at some point.
  6022   - Users are strongly encouraged to write "0 < n" rather than
  6023     "n ~= 0". Theorems and proof tools have been modified towards this
  6024     `standard'.
  6025 
  6026 * HOL/Lists:
  6027   the function "set_of_list" has been renamed "set" (and its theorems too);
  6028   the function "nth" now takes its arguments in the reverse order and
  6029   has acquired the infix notation "!" as in "xs!n".
  6030 
  6031 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  6032 
  6033 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  6034   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  6035 
  6036 * HOL/record: extensible records with schematic structural subtyping
  6037 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  6038 still lacks various theorems and concrete record syntax;
  6039 
  6040 
  6041 *** HOLCF ***
  6042 
  6043 * removed "axioms" and "generated by" sections;
  6044 
  6045 * replaced "ops" section by extended "consts" section, which is capable of
  6046   handling the continuous function space "->" directly;
  6047 
  6048 * domain package:
  6049   . proves theorems immediately and stores them in the theory,
  6050   . creates hierachical name space,
  6051   . now uses normal mixfix annotations (instead of cinfix...),
  6052   . minor changes to some names and values (for consistency),
  6053   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  6054   . separator between mutual domain defs: changed "," to "and",
  6055   . improved handling of sort constraints;  now they have to
  6056     appear on the left-hand side of the equations only;
  6057 
  6058 * fixed LAM <x,y,zs>.b syntax;
  6059 
  6060 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  6061 adm (%x. P (t x)), where P is chainfinite and t continuous;
  6062 
  6063 
  6064 *** FOL and ZF ***
  6065 
  6066 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6067   with `addloop' of the simplifier to faciliate case splitting in premises.
  6068 
  6069 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6070 in HOL, they strip ALL and --> from proved theorems;
  6071 
  6072 
  6073 
  6074 New in Isabelle94-8 (May 1997)
  6075 ------------------------------
  6076 
  6077 *** General Changes ***
  6078 
  6079 * new utilities to build / run / maintain Isabelle etc. (in parts
  6080 still somewhat experimental); old Makefiles etc. still functional;
  6081 
  6082 * new 'Isabelle System Manual';
  6083 
  6084 * INSTALL text, together with ./configure and ./build scripts;
  6085 
  6086 * reimplemented type inference for greater efficiency, better error
  6087 messages and clean internal interface;
  6088 
  6089 * prlim command for dealing with lots of subgoals (an easier way of
  6090 setting goals_limit);
  6091 
  6092 
  6093 *** Syntax ***
  6094 
  6095 * supports alternative (named) syntax tables (parser and pretty
  6096 printer); internal interface is provided by add_modesyntax(_i);
  6097 
  6098 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6099 be used in conjunction with the Isabelle symbol font; uses the
  6100 "symbols" syntax table;
  6101 
  6102 * added token_translation interface (may translate name tokens in
  6103 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6104 the current print_mode); IMPORTANT: user print translation functions
  6105 are responsible for marking newly introduced bounds
  6106 (Syntax.mark_boundT);
  6107 
  6108 * token translations for modes "xterm" and "xterm_color" that display
  6109 names in bold, underline etc. or colors (which requires a color
  6110 version of xterm);
  6111 
  6112 * infixes may now be declared with names independent of their syntax;
  6113 
  6114 * added typed_print_translation (like print_translation, but may
  6115 access type of constant);
  6116 
  6117 
  6118 *** Classical Reasoner ***
  6119 
  6120 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6121 some limitations.  Blast_tac...
  6122   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6123   + ignores elimination rules that don't have the correct format
  6124         (the conclusion MUST be a formula variable)
  6125   + ignores types, which can make HOL proofs fail
  6126   + rules must not require higher-order unification, e.g. apply_type in ZF
  6127     [message "Function Var's argument not a bound variable" relates to this]
  6128   + its proof strategy is more general but can actually be slower
  6129 
  6130 * substitution with equality assumptions no longer permutes other
  6131 assumptions;
  6132 
  6133 * minor changes in semantics of addafter (now called addaltern); renamed
  6134 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6135 (and access functions for it);
  6136 
  6137 * improved combination of classical reasoner and simplifier:
  6138   + functions for handling clasimpsets
  6139   + improvement of addss: now the simplifier is called _after_ the
  6140     safe steps.
  6141   + safe variant of addss called addSss: uses safe simplifications
  6142     _during_ the safe steps. It is more complete as it allows multiple
  6143     instantiations of unknowns (e.g. with slow_tac).
  6144 
  6145 *** Simplifier ***
  6146 
  6147 * added interface for simplification procedures (functions that
  6148 produce *proven* rewrite rules on the fly, depending on current
  6149 redex);
  6150 
  6151 * ordering on terms as parameter (used for ordered rewriting);
  6152 
  6153 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6154 
  6155 * the solver is now split into a safe and an unsafe part.
  6156 This should be invisible for the normal user, except that the
  6157 functions setsolver and addsolver have been renamed to setSolver and
  6158 addSolver; added safe_asm_full_simp_tac;
  6159 
  6160 
  6161 *** HOL ***
  6162 
  6163 * a generic induction tactic `induct_tac' which works for all datatypes and
  6164 also for type `nat';
  6165 
  6166 * a generic case distinction tactic `exhaust_tac' which works for all
  6167 datatypes and also for type `nat';
  6168 
  6169 * each datatype comes with a function `size';
  6170 
  6171 * patterns in case expressions allow tuple patterns as arguments to
  6172 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6173 
  6174 * primrec now also works with type nat;
  6175 
  6176 * recdef: a new declaration form, allows general recursive functions to be
  6177 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6178 
  6179 * the constant for negation has been renamed from "not" to "Not" to
  6180 harmonize with FOL, ZF, LK, etc.;
  6181 
  6182 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6183 infinite lists;
  6184 
  6185 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6186 
  6187 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6188 problems in commutative rings, using axiomatic type classes for + and *;
  6189 
  6190 * more examples in HOL/MiniML and HOL/Auth;
  6191 
  6192 * more default rewrite rules for quantifiers, union/intersection;
  6193 
  6194 * a new constant `arbitrary == @x.False';
  6195 
  6196 * HOLCF/IOA replaces old HOL/IOA;
  6197 
  6198 * HOLCF changes: derived all rules and arities
  6199   + axiomatic type classes instead of classes
  6200   + typedef instead of faking type definitions
  6201   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6202   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6203   + eliminated the types void, one, tr
  6204   + use unit lift and bool lift (with translations) instead of one and tr
  6205   + eliminated blift from Lift3.thy (use Def instead of blift)
  6206   all eliminated rules are derived as theorems --> no visible changes ;
  6207 
  6208 
  6209 *** ZF ***
  6210 
  6211 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6212 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6213 as ZF_cs addSIs [equalityI];
  6214 
  6215 
  6216 
  6217 New in Isabelle94-7 (November 96)
  6218 ---------------------------------
  6219 
  6220 * allowing negative levels (as offsets) in prlev and choplev;
  6221 
  6222 * super-linear speedup for large simplifications;
  6223 
  6224 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6225 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6226 FAIL); can suppress it using the command Delsimps (ex_simps @
  6227 all_simps); De Morgan laws are also now included, by default;
  6228 
  6229 * improved printing of ==>  :  ~:
  6230 
  6231 * new object-logic "Sequents" adds linear logic, while replacing LK
  6232 and Modal (thanks to Sara Kalvala);
  6233 
  6234 * HOL/Auth: correctness proofs for authentication protocols;
  6235 
  6236 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6237 examples on HOL/Auth);
  6238 
  6239 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6240 the rewriter and classical reasoner simultaneously;
  6241 
  6242 * function uresult no longer returns theorems in "standard" format;
  6243 regain previous version by: val uresult = standard o uresult;
  6244 
  6245 
  6246 
  6247 New in Isabelle94-6
  6248 -------------------
  6249 
  6250 * oracles -- these establish an interface between Isabelle and trusted
  6251 external reasoners, which may deliver results as theorems;
  6252 
  6253 * proof objects (in particular record all uses of oracles);
  6254 
  6255 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6256 
  6257 * "constdefs" section in theory files;
  6258 
  6259 * "primrec" section (HOL) no longer requires names;