NEWS
author wenzelm
Mon Mar 16 17:51:07 2009 +0100 (2009-03-16)
changeset 30547 4c2514625873
parent 30539 c96c72709a20
child 30562 7b0017587e7d
permissions -rw-r--r--
simplifief 'method_setup' command;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * The main reference manuals (isar-ref, implementation, system) have
    10 been updated and extended.  Formally checked references as hyperlinks
    11 are now available in uniform manner.
    12 
    13 * Simplified main Isabelle executables, with less surprises on
    14 case-insensitive file-systems (such as Mac OS).
    15 
    16   - The main Isabelle tool wrapper is now called "isabelle" instead of
    17     "isatool."
    18 
    19   - The former "isabelle" alias for "isabelle-process" has been
    20     removed (should rarely occur to regular users).
    21 
    22   - The former "isabelle-interface" and its alias "Isabelle" have been
    23     removed (interfaces are now regular Isabelle tools).
    24 
    25 Within scripts and make files, the Isabelle environment variables
    26 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    27 respectively.  (The latter are still available as legacy feature.)
    28 
    29 The old isabelle-interface wrapper could react in confusing ways if
    30 the interface was uninstalled or changed otherwise.  Individual
    31 interface tool configuration is now more explicit, see also the
    32 Isabelle system manual.  In particular, Proof General is now available
    33 via "isabelle emacs".
    34 
    35 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    36 purge installed copies of Isabelle executables and re-run "isabelle
    37 install -p ...", or use symlinks.
    38 
    39 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    40 old ~/isabelle, which was slightly non-standard and apt cause
    41 surprises on case-insensitive file-systems.
    42 
    43 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    44 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    45 care is required when using older releases of Isabelle.  Note that
    46 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    47 Isabelle distribution.
    48 
    49 * Proofs of fully specified statements are run in parallel on
    50 multi-core systems.  A speedup factor of 2-3 can be expected on a
    51 regular 4-core machine, if the initial heap space is made reasonably
    52 large (cf. Poly/ML option -H).  [Poly/ML 5.2.1 or later]
    53 
    54 * Generalized Isar history, with support for linear undo, direct state
    55 addressing etc.
    56 
    57 * Recovered hiding of consts, which was accidentally broken in
    58 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
    59 makes c inaccessible; consider using ``hide (open) const c'' instead.
    60 
    61 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
    62 interface instead.
    63 
    64 * There is a new syntactic category "float_const" for signed decimal
    65 fractions (e.g. 123.45 or -123.45).
    66 
    67 * New prover for coherent logic (see src/Tools/coherent.ML).
    68 
    69 
    70 *** Pure ***
    71 
    72 * Class declaration: sc. "base sort" must not be given in import list
    73 any longer but is inferred from the specification.  Particularly in HOL,
    74 write
    75 
    76     class foo = ...     instead of      class foo = type + ...
    77 
    78 * Module moves in repository:
    79     src/Pure/Tools/value.ML ~> src/Tools/
    80     src/Pure/Tools/quickcheck.ML ~> src/Tools/
    81 
    82 * Slightly more coherent Pure syntax, with updated documentation in
    83 isar-ref manual.  Removed locales meta_term_syntax and
    84 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
    85 INCOMPATIBILITY in rare situations.
    86 
    87 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
    88 hypotheses.  Sorts required in the course of reasoning need to be
    89 covered by the constraints in the initial statement, completed by the
    90 type instance information of the background theory.  Non-trivial sort
    91 hypotheses, which rarely occur in practice, may be specified via
    92 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
    93 
    94   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
    95 
    96 The result contains an implicit sort hypotheses as before --
    97 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
    98 normalization.
    99 
   100 * Changed defaults for unify configuration options:
   101 
   102   unify_trace_bound = 50 (formerly 25)
   103   unify_search_bound = 60 (formerly 30)
   104 
   105 * Different bookkeeping for code equations (INCOMPATIBILITY):
   106 
   107   a) On theory merge, the last set of code equations for a particular
   108      constant is taken (in accordance with the policy applied by other
   109      parts of the code generator framework).
   110 
   111   b) Code equations stemming from explicit declarations (e.g. code
   112      attribute) gain priority over default code equations stemming
   113      from definition, primrec, fun etc.
   114 
   115 * Global versions of theorems stemming from classes do not carry a
   116 parameter prefix any longer.  INCOMPATIBILITY.
   117 
   118 * Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   119 In existing theorem specifications replace the includes element by the
   120 respective context elements of the included locale, omitting those
   121 that are already present in the theorem specification.  Multiple
   122 assume elements of a locale should be replaced by a single one
   123 involving the locale predicate.  In the proof body, declarations (most
   124 notably theorems) may be regained by interpreting the respective
   125 locales in the proof context as required (command "interpret").
   126 
   127 If using "includes" in replacement of a target solely because the
   128 parameter types in the theorem are not as general as in the target,
   129 consider declaring a new locale with additional type constraints on
   130 the parameters (context element "constrains").
   131 
   132 * Dropped "locale (open)".  INCOMPATIBILITY.
   133 
   134 * Interpretation commands no longer attempt to simplify goal.
   135 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   136 methods intro_locales and unfold_locales to clarify.
   137 
   138 * Interpretation commands no longer accept interpretation attributes.
   139 INCOMPATBILITY.
   140 
   141 * Complete re-implementation of locales.  INCOMPATIBILITY.  The most
   142 important changes are listed below.  See documentation (forthcoming)
   143 and tutorial (also forthcoming) for details.
   144 
   145 - In locale expressions, instantiation replaces renaming.  Parameters
   146 must be declared in a for clause.  To aid compatibility with previous
   147 parameter inheritance, in locale declarations, parameters that are not
   148 'touched' (instantiation position "_" or omitted) are implicitly added
   149 with their syntax at the beginning of the for clause.
   150 
   151 - Syntax from abbreviations and definitions in locales is available in
   152 locale expressions and context elements.  The latter is particularly
   153 useful in locale declarations.
   154 
   155 - More flexible mechanisms to qualify names generated by locale
   156 expressions.  Qualifiers (prefixes) may be specified in locale
   157 expressions.  Available are normal qualifiers (syntax "name:") and
   158 strict qualifiers (syntax "name!:").  The latter must occur in name
   159 references and are useful to avoid accidental hiding of names, the
   160 former are optional.  Qualifiers derived from the parameter names of a
   161 locale are no longer generated.
   162 
   163 - "sublocale l < e" replaces "interpretation l < e".  The
   164 instantiation clause in "interpretation" and "interpret" (square
   165 brackets) is no longer available.  Use locale expressions.
   166 
   167 - When converting proof scripts, be sure to replace qualifiers in
   168 "interpretation" and "interpret" by strict qualifiers.  Qualifiers in
   169 locale expressions range over a single locale instance only.
   170 
   171 * Command 'instance': attached definitions no longer accepted.
   172 INCOMPATIBILITY, use proper 'instantiation' target.
   173 
   174 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   175 
   176 * The 'axiomatization' command now only works within a global theory
   177 context.  INCOMPATIBILITY.
   178 
   179 * New find_theorems criterion "solves" matching theorems that directly
   180 solve the current goal. Try "find_theorems solves".
   181 
   182 * Added an auto solve option, which can be enabled through the
   183 ProofGeneral Isabelle settings menu (disabled by default).
   184  
   185 When enabled, find_theorems solves is called whenever a new lemma is
   186 stated. Any theorems that could solve the lemma directly are listed
   187 underneath the goal.
   188 
   189 * New command 'find_consts' searches for constants based on type and
   190 name patterns, e.g.
   191 
   192     find_consts "_ => bool"
   193 
   194 By default, matching is against subtypes, but it may be restricted to
   195 the whole type. Searching by name is possible. Multiple queries are
   196 conjunctive and queries may be negated by prefixing them with a
   197 hyphen:
   198 
   199     find_consts strict: "_ => bool" name: "Int" -"int => int"
   200 
   201 * New command 'local_setup' is similar to 'setup', but operates on a
   202 local theory context.
   203 
   204 
   205 *** Document preparation ***
   206 
   207 * Antiquotation @{lemma} now imitates a regular terminal proof,
   208 demanding keyword 'by' and supporting the full method expression
   209 syntax just like the Isar command 'by'.
   210 
   211 
   212 *** HOL ***
   213 
   214 * Theory Library/Diagonalize.thy provides constructive version of
   215 Cantor's first diagonalization argument.
   216 
   217 * New predicate "strict_mono" classifies strict functions on partial orders.
   218 With strict functions on linear orders, reasoning about (in)equalities is
   219 facilitated by theorems "strict_mono_eq", "strict_mono_less_eq" and "strict_mono_less".
   220 
   221 * Some set operations are now proper qualified constants with authentic syntax.
   222 INCOMPATIBILITY:
   223 
   224     op Int ~>   Set.Int
   225     op Un ~>    Set.Un
   226     INTER ~>    Set.INTER
   227     UNION ~>    Set.UNION
   228     Inter ~>    Set.Inter
   229     Union ~>    Set.Union
   230     {} ~>       Set.empty
   231     UNIV ~>     Set.UNIV
   232 
   233 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in theory
   234 Set.
   235 
   236 * Auxiliary class "itself" has disappeared -- classes without any parameter
   237 are treated as expected by the 'class' command.
   238 
   239 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   240 
   241 * Common decision procedures (Cooper, MIR, Ferrack, Approximation, Dense_Linear_Order)
   242 now in directory HOL/Decision_Procs.
   243 
   244 * Theory HOL/Decisioin_Procs/Approximation.thy provides the new proof method
   245 "approximation".  It proves formulas on real values by using interval arithmetic.
   246 In the formulas are also the transcendental functions sin, cos, tan, atan, ln,
   247 exp and the constant pi are allowed. For examples see
   248 HOL/Descision_Procs/ex/Approximation_Ex.thy.
   249 
   250 * Theory "Reflection" now resides in HOL/Library.
   251 
   252 * Entry point to Word library now simply named "Word".  INCOMPATIBILITY.
   253 
   254 * Made source layout more coherent with logical distribution
   255 structure:
   256 
   257     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   258     src/HOL/Library/Code_Message.thy ~> src/HOL/
   259     src/HOL/Library/GCD.thy ~> src/HOL/
   260     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   261     src/HOL/Library/Parity.thy ~> src/HOL/
   262     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   263     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   264     src/HOL/Real/Lubs.thy ~> src/HOL/
   265     src/HOL/Real/PReal.thy ~> src/HOL/
   266     src/HOL/Real/Rational.thy ~> src/HOL/
   267     src/HOL/Real/RComplete.thy ~> src/HOL/
   268     src/HOL/Real/RealDef.thy ~> src/HOL/
   269     src/HOL/Real/RealPow.thy ~> src/HOL/
   270     src/HOL/Real/Real.thy ~> src/HOL/
   271     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   272     src/HOL/Complex/Complex.thy ~> src/HOL/
   273     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   274     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   275     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   276     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   277     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   278     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   279     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   280     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   281     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   282     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   283     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   284     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   285     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   286     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   287     src/HOL/Real/Float ~> src/HOL/Library/
   288     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   289     src/HOL/Real/RealVector.thy ~> src/HOL/
   290 
   291     src/HOL/arith_data.ML ~> src/HOL/Tools
   292     src/HOL/hologic.ML ~> src/HOL/Tools
   293     src/HOL/simpdata.ML ~> src/HOL/Tools
   294     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   295     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   296     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   297     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   298     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   299     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   300     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   301 
   302     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   303     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   304     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   305     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   306     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   307     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   308 
   309 * If methods "eval" and "evaluation" encounter a structured proof state
   310 with !!/==>, only the conclusion is evaluated to True (if possible),
   311 avoiding strange error messages.
   312 
   313 * Simplifier: simproc for let expressions now unfolds if bound variable
   314 occurs at most once in let expression body.  INCOMPATIBILITY.
   315 
   316 * New classes "top" and "bot" with corresponding operations "top" and "bot"
   317 in theory Orderings;  instantiation of class "complete_lattice" requires
   318 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   319 
   320 * Changed definition lemma "less_fun_def" in order to provide an instance
   321 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   322 
   323 * Unified theorem tables for both code code generators.  Thus
   324 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   325 
   326 * Constants "undefined" and "default" replace "arbitrary".  Usually
   327 "undefined" is the right choice to replace "arbitrary", though logically
   328 there is no difference.  INCOMPATIBILITY.
   329 
   330 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   331 Posix processes.  Avoids potentially expensive forking of the ML
   332 process.  New thread-based implementation also works on non-Unix
   333 platforms (Cygwin).  Provers are no longer hardwired, but defined
   334 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   335 commands are covered in the isar-ref manual.
   336 
   337 * Wrapper scripts for remote SystemOnTPTP service allows to use
   338 sledgehammer without local ATP installation (Vampire etc.). Other
   339 provers may be included via suitable ML wrappers, see also
   340 src/HOL/ATP_Linkup.thy.
   341 
   342 * Normalization by evaluation now allows non-leftlinear equations.
   343 Declare with attribute [code nbe].
   344 
   345 * Command "value" now integrates different evaluation
   346 mechanisms.  The result of the first successful evaluation mechanism
   347 is printed.  In square brackets a particular named evaluation
   348 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   349 further src/HOL/ex/Eval_Examples.thy.
   350 
   351 * New method "sizechange" to automate termination proofs using (a
   352 modification of) the size-change principle. Requires SAT solver. See
   353 src/HOL/ex/Termination.thy for examples.
   354 
   355 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   356 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   357 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   358 
   359 * HOL/Orderings: added class "preorder" as superclass of "order".
   360 INCOMPATIBILITY: Instantiation proofs for order, linorder
   361 etc. slightly changed.  Some theorems named order_class.* now named
   362 preorder_class.*.
   363 
   364 * HOL/Relation:
   365 Renamed "refl" to "refl_on", "reflexive" to "refl, "diag" to "Id_on".
   366 
   367 * HOL/Finite_Set: added a new fold combinator of type
   368   ('a => 'b => 'b) => 'b => 'a set => 'b
   369 Occasionally this is more convenient than the old fold combinator which is
   370 now defined in terms of the new one and renamed to fold_image.
   371 
   372 * HOL/Ring_and_Field and HOL/OrderedGroup: The lemmas "group_simps" and
   373 "ring_simps" have been replaced by "algebra_simps" (which can be extended with
   374 further lemmas!). At the moment both still exist but the former will disappear
   375 at some point.
   376 
   377 * HOL/Power: Lemma power_Suc is now declared as a simp rule in class
   378 recpower.  Type-specific simp rules for various recpower types have
   379 been removed.  INCOMPATIBILITY.  Rename old lemmas as follows:
   380 
   381 rat_power_0    -> power_0
   382 rat_power_Suc  -> power_Suc
   383 realpow_0      -> power_0
   384 realpow_Suc    -> power_Suc
   385 complexpow_0   -> power_0
   386 complexpow_Suc -> power_Suc
   387 power_poly_0   -> power_0
   388 power_poly_Suc -> power_Suc
   389 
   390 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   391 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   392 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   393 of lemmas from Divides has been generalized from nat to class
   394 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   395 renames resulting from duplicate elimination:
   396 
   397     dvd_def_mod ~>          dvd_eq_mod_eq_0
   398     zero_dvd_iff ~>         dvd_0_left_iff
   399     dvd_0 ~>                dvd_0_right
   400     DIVISION_BY_ZERO_DIV ~> div_by_0
   401     DIVISION_BY_ZERO_MOD ~> mod_by_0
   402     mult_div ~>             div_mult_self2_is_id
   403     mult_mod ~>             mod_mult_self2_is_0
   404 
   405 * HOL/IntDiv: removed many lemmas that are instances of class-based
   406 generalizations (from Divides and Ring_and_Field).
   407 INCOMPATIBILITY. Rename old lemmas as follows:
   408 
   409 dvd_diff               -> nat_dvd_diff
   410 dvd_zminus_iff         -> dvd_minus_iff
   411 mod_add1_eq            -> mod_add_eq
   412 mod_mult1_eq           -> mod_mult_right_eq
   413 mod_mult1_eq'          -> mod_mult_left_eq
   414 mod_mult_distrib_mod   -> mod_mult_eq
   415 nat_mod_add_left_eq    -> mod_add_left_eq
   416 nat_mod_add_right_eq   -> mod_add_right_eq
   417 nat_mod_div_trivial    -> mod_div_trivial
   418 nat_mod_mod_trivial    -> mod_mod_trivial
   419 zdiv_zadd_self1        -> div_add_self1
   420 zdiv_zadd_self2        -> div_add_self2
   421 zdiv_zmult_self1       -> div_mult_self2_is_id
   422 zdiv_zmult_self2       -> div_mult_self1_is_id
   423 zdvd_triv_left         -> dvd_triv_left
   424 zdvd_triv_right        -> dvd_triv_right
   425 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   426 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   427 zmod_zadd_left_eq      -> mod_add_left_eq
   428 zmod_zadd_right_eq     -> mod_add_right_eq
   429 zmod_zadd_self1        -> mod_add_self1
   430 zmod_zadd_self2        -> mod_add_self2
   431 zmod_zadd1_eq          -> mod_add_eq
   432 zmod_zdiff1_eq         -> mod_diff_eq
   433 zmod_zdvd_zmod         -> mod_mod_cancel
   434 zmod_zmod_cancel       -> mod_mod_cancel
   435 zmod_zmult_self1       -> mod_mult_self2_is_0
   436 zmod_zmult_self2       -> mod_mult_self1_is_0
   437 zmod_1                 -> mod_by_1
   438 zdiv_1                 -> div_by_1
   439 zdvd_abs1              -> abs_dvd_iff
   440 zdvd_abs2              -> dvd_abs_iff
   441 zdvd_refl              -> dvd_refl
   442 zdvd_trans             -> dvd_trans
   443 zdvd_zadd              -> dvd_add
   444 zdvd_zdiff             -> dvd_diff
   445 zdvd_zminus_iff        -> dvd_minus_iff
   446 zdvd_zminus2_iff       -> minus_dvd_iff
   447 zdvd_zmultD            -> dvd_mult_right
   448 zdvd_zmultD2           -> dvd_mult_left
   449 zdvd_zmult_mono        -> mult_dvd_mono
   450 zdvd_0_right           -> dvd_0_right
   451 zdvd_0_left            -> dvd_0_left_iff
   452 zdvd_1_left            -> one_dvd
   453 zminus_dvd_iff         -> minus_dvd_iff
   454 
   455 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   456 zlcm (for int); carried together from various gcd/lcm developements in
   457 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   458 corresponding theorems renamed accordingly.  INCOMPATIBILITY.  To
   459 recover tupled syntax, use syntax declarations like:
   460 
   461     hide (open) const gcd
   462     abbreviation gcd where
   463       "gcd == (%(a, b). GCD.gcd a b)"
   464     notation (output)
   465       GCD.gcd ("gcd '(_, _')")
   466 
   467 (analogously for lcm, zgcd, zlcm).
   468 
   469 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   470 
   471 * The real numbers offer decimal input syntax: 12.34 is translated into
   472   1234/10^2. This translation is not reversed upon output.
   473 
   474 * New ML antiquotation @{code}: takes constant as argument, generates
   475 corresponding code in background and inserts name of the corresponding
   476 resulting ML value/function/datatype constructor binding in place.
   477 All occurrences of @{code} with a single ML block are generated
   478 simultaneously.  Provides a generic and safe interface for
   479 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   480 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   481 application.  In future you ought refrain from ad-hoc compiling
   482 generated SML code on the ML toplevel.  Note that (for technical
   483 reasons) @{code} cannot refer to constants for which user-defined
   484 serializations are set.  Refer to the corresponding ML counterpart
   485 directly in that cases.
   486 
   487 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   488 Complex_Main.thy remain as they are.
   489 
   490 * New image HOL-Plain provides a minimal HOL with the most important
   491 tools available (inductive, datatype, primrec, ...).  By convention
   492 the corresponding theory Plain should be ancestor of every further
   493 (library) theory.  Some library theories now have ancestor Plain
   494 (instead of Main), thus theory Main occasionally has to be imported
   495 explicitly.
   496 
   497 * The metis method now fails in the usual manner, rather than raising
   498 an exception, if it determines that it cannot prove the theorem.
   499 
   500 * The metis method no longer fails because the theorem is too trivial
   501 (contains the empty clause).
   502 
   503 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   504 as the structured Isar versions "cases" and "induct", cf. the
   505 corresponding "cases" and "induct" attributes.  Mutual induction rules
   506 are now presented as a list of individual projections
   507 (e.g. foo_bar.inducts for types foo and bar); the old format with
   508 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   509 rare situations a different rule is selected --- notably nested tuple
   510 elimination instead of former prod.exhaust: use explicit (case_tac t
   511 rule: prod.exhaust) here.
   512 
   513 * Attributes "cases", "induct", "coinduct" support "del" option.
   514 
   515 * Removed fact "case_split_thm", which duplicates "case_split".
   516 
   517 * Command 'rep_datatype': instead of theorem names the command now
   518 takes a list of terms denoting the constructors of the type to be
   519 represented as datatype.  The characteristic theorems have to be
   520 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   521 have disappeared in favour of existing ones:
   522 
   523     unit_induct                 ~> unit.induct
   524     prod_induct                 ~> prod.induct
   525     sum_induct                  ~> sum.induct
   526     Suc_Suc_eq                  ~> nat.inject
   527     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   528 
   529 * The option datatype has been moved to a new theory HOL/Option.thy.
   530 Renamed option_map to Option.map, and o2s to Option.set.
   531 
   532 * Library/Nat_Infinity: added addition, numeral syntax and more
   533 instantiations for algebraic structures.  Removed some duplicate
   534 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   535 
   536 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   537 menu.
   538 
   539 * Linear arithmetic now ignores all inequalities when
   540 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   541 
   542 
   543 *** HOL-Algebra ***
   544 
   545 * New locales for orders and lattices where the equivalence relation
   546 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   547 locales use a record structure with field eq for the equivalence.
   548 
   549 * New theory of factorial domains.
   550 
   551 * Units_l_inv and Units_r_inv are now simprules by default.
   552 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   553 and/or r_inv will now also require deletion of these lemmas.
   554 
   555 * Renamed the following theorems.  INCOMPATIBILITY.
   556 UpperD ~> Upper_memD
   557 LowerD ~> Lower_memD
   558 least_carrier ~> least_closed
   559 greatest_carrier ~> greatest_closed
   560 greatest_Lower_above ~> greatest_Lower_below
   561 one_zero ~> carrier_one_zero
   562 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   563 
   564 
   565 *** HOL-NSA ***
   566 
   567 * Created new image HOL-NSA, containing theories of nonstandard
   568 analysis which were previously part of HOL-Complex.  Entry point
   569 Hyperreal.thy remains valid, but theories formerly using
   570 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   571 
   572 
   573 *** ZF ***
   574 
   575 * Proof of Zorn's Lemma for partial orders.
   576 
   577 
   578 *** HOLCF ***
   579 
   580 * Reimplemented the simplification procedure for proving continuity
   581 subgoals.  The new simproc is extensible; users can declare additional
   582 continuity introduction rules with the attribute [cont2cont].
   583 
   584 * The continuity simproc now uses a different introduction rule for
   585 solving continuity subgoals on terms with lambda abstractions.  In
   586 some rare cases the new simproc may fail to solve subgoals that the
   587 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   588 Potential INCOMPATIBILITY.
   589 
   590 * The syntax of the fixrec package has changed.  The specification
   591 syntax now conforms in style to definition, primrec, function, etc.
   592 See HOLCF/ex/Fixrec_ex.thy for examples.  INCOMPATIBILITY.
   593 
   594 
   595 *** ML ***
   596 
   597 * High-level support for concurrent ML programming, see
   598 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   599 particularly convenient to organize independent functional
   600 computations.  The concept of "synchronized variables" provides a
   601 higher-order interface for components with shared state, avoiding the
   602 delicate details of mutexes and condition variables.  [Poly/ML 5.2.1
   603 or later]
   604 
   605 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   606 and Method.setup, as well as commands 'attribute_setup' and
   607 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   608 existing code accordingly, or use plain 'setup' together with old
   609 Method.add_method.
   610 
   611 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   612 to 'a -> thm, while results are always tagged with an authentic oracle
   613 name.  The Isar command 'oracle' is now polymorphic, no argument type
   614 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   615 accordingly.  Note that extra performance may be gained by producing
   616 the cterm carefully, avoiding slow Thm.cterm_of.
   617 
   618 * ML bindings produced via Isar commands are stored within the Isar
   619 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   620 become thread-safe and work with undo as expected (concerning
   621 top-level bindings, not side-effects on global references).
   622 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   623 compiler at runtime; really global bindings need to be given outside a
   624 theory. [Poly/ML 5.2 or later]
   625 
   626 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   627 context. Top-level ML bindings are stored within the proof context in
   628 a purely sequential fashion, disregarding the nested proof structure.
   629 ML bindings introduced by 'ML_prf' are discarded at the end of the
   630 proof.  [Poly/ML 5.2 or later]
   631 
   632 * Generic Toplevel.add_hook interface allows to analyze the result of
   633 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   634 for theorem dependency output of transactions resulting in a new
   635 theory state.
   636 
   637 * More systematic treatment of long names, abstract name bindings, and
   638 name space operations.  Basic operations on qualified names have been
   639 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   640 Long_Name.append.  Old type bstring has been mostly replaced by
   641 abstract type binding (see structure Binding), which supports precise
   642 qualification (by packages and local theory targets), as well as
   643 proper tracking of source positions.  INCOMPATIBILITY, need to wrap
   644 old bstring values into Binding.name, or better pass through abstract
   645 bindings everywhere.  See further src/Pure/General/long_name.ML,
   646 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   647 
   648 * Simplified interface for defining document antiquotations via
   649 ThyOutput.antiquotation, ThyOutput.output, and optionally
   650 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   651 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   652 examples.
   653 
   654 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   655 LocalTheory.note etc.) now refer to the *full* internal name, not the
   656 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   657 
   658 * Rules and tactics that read instantiations (read_instantiate,
   659 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   660 context, which is required for parsing and type-checking.  Moreover,
   661 the variables are specified as plain indexnames, not string encodings
   662 thereof.  INCOMPATIBILITY.
   663 
   664 * Disposed old type and term read functions (Sign.read_def_typ,
   665 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   666 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   667 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   668 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   669 resort for legacy applications.
   670 
   671 * Antiquotations: block-structured compilation context indicated by
   672 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   673 
   674   @{let ?pat = term}                      - term abbreviation (HO matching)
   675   @{note name = fact}                     - fact abbreviation
   676   @{thm fact}                             - singleton fact (with attributes)
   677   @{thms fact}                            - general fact (with attributes)
   678   @{lemma prop by method}                 - singleton goal
   679   @{lemma prop by meth1 meth2}            - singleton goal
   680   @{lemma prop1 ... propN by method}      - general goal
   681   @{lemma prop1 ... propN by meth1 meth2} - general goal
   682   @{lemma (open) ...}                     - open derivation
   683 
   684 
   685 *** System ***
   686 
   687 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   688 Poly/ML 5.2.1 or later.
   689 
   690 * The Isabelle "emacs" tool provides a specific interface to invoke
   691 Proof General / Emacs, with more explicit failure if that is not
   692 installed (the old isabelle-interface script silently falls back on
   693 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   694 installation location of the Proof General distribution.
   695 
   696 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   697 the Isabelle process into a JVM/Scala application.  See
   698 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   699 process wrapper has been discontinued.)
   700 
   701 * Status messages (with exact source position information) are
   702 emitted, if proper markup print mode is enabled.  This allows
   703 user-interface components to provide detailed feedback on internal
   704 prover operations.
   705 
   706 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   707 
   708 
   709 
   710 New in Isabelle2008 (June 2008)
   711 -------------------------------
   712 
   713 *** General ***
   714 
   715 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   716 and updated, with formally checked references as hyperlinks.
   717 
   718 * Theory loader: use_thy (and similar operations) no longer set the
   719 implicit ML context, which was occasionally hard to predict and in
   720 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   721 provides a proper context already.
   722 
   723 * Theory loader: old-style ML proof scripts being *attached* to a thy
   724 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   725 'use' within a theory file will do the job.
   726 
   727 * Name space merge now observes canonical order, i.e. the second space
   728 is inserted into the first one, while existing entries in the first
   729 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   730 swap theory imports.
   731 
   732 * Syntax: symbol \<chi> is now considered a letter.  Potential
   733 INCOMPATIBILITY in identifier syntax etc.
   734 
   735 * Outer syntax: string tokens no longer admit escaped white space,
   736 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   737 white space without escapes.
   738 
   739 * Outer syntax: string tokens may contain arbitrary character codes
   740 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   741 "foo_bar".
   742 
   743 
   744 *** Pure ***
   745 
   746 * Context-dependent token translations.  Default setup reverts locally
   747 fixed variables, and adds hilite markup for undeclared frees.
   748 
   749 * Unused theorems can be found using the new command 'unused_thms'.
   750 There are three ways of invoking it:
   751 
   752 (1) unused_thms
   753      Only finds unused theorems in the current theory.
   754 
   755 (2) unused_thms thy_1 ... thy_n -
   756      Finds unused theorems in the current theory and all of its ancestors,
   757      excluding the theories thy_1 ... thy_n and all of their ancestors.
   758 
   759 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   760      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   761      their ancestors, excluding the theories thy_1 ... thy_n and all of
   762      their ancestors.
   763 
   764 In order to increase the readability of the list produced by
   765 unused_thms, theorems that have been created by a particular instance
   766 of a theory command such as 'inductive' or 'function' are considered
   767 to belong to the same "group", meaning that if at least one theorem in
   768 this group is used, the other theorems in the same group are no longer
   769 reported as unused.  Moreover, if all theorems in the group are
   770 unused, only one theorem in the group is displayed.
   771 
   772 Note that proof objects have to be switched on in order for
   773 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   774 usually the case when using Proof General with the default settings).
   775 
   776 * Authentic naming of facts disallows ad-hoc overwriting of previous
   777 theorems within the same name space.  INCOMPATIBILITY, need to remove
   778 duplicate fact bindings, or even accidental fact duplications.  Note
   779 that tools may maintain dynamically scoped facts systematically, using
   780 PureThy.add_thms_dynamic.
   781 
   782 * Command 'hide' now allows to hide from "fact" name space as well.
   783 
   784 * Eliminated destructive theorem database, simpset, claset, and
   785 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   786 update of theories within ML code.
   787 
   788 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   789 INCOMPATIBILITY, object-logics depending on former Pure require
   790 additional setup PureThy.old_appl_syntax_setup; object-logics
   791 depending on former CPure need to refer to Pure.
   792 
   793 * Commands 'use' and 'ML' are now purely functional, operating on
   794 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   795 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   796 INCOMPATIBILITY.
   797 
   798 * Command 'setup': discontinued implicit version with ML reference.
   799 
   800 * Instantiation target allows for simultaneous specification of class
   801 instance operations together with an instantiation proof.
   802 Type-checking phase allows to refer to class operations uniformly.
   803 See src/HOL/Complex/Complex.thy for an Isar example and
   804 src/HOL/Library/Eval.thy for an ML example.
   805 
   806 * Indexing of literal facts: be more serious about including only
   807 facts from the visible specification/proof context, but not the
   808 background context (locale etc.).  Affects `prop` notation and method
   809 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   810 situations.
   811 
   812 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   813 "(open)" option, which used to expose internal bound variables to the
   814 proof text.
   815 
   816 * Isar statements: removed obsolete case "rule_context".
   817 INCOMPATIBILITY, better use explicit fixes/assumes.
   818 
   819 * Locale proofs: default proof step now includes 'unfold_locales';
   820 hence 'proof' without argument may be used to unfold locale
   821 predicates.
   822 
   823 
   824 *** Document preparation ***
   825 
   826 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   827 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   828 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   829 spot); renamed link color from "darkblue" to "linkcolor" (default
   830 value unchanged, can be redefined via \definecolor); no longer sets
   831 "a4paper" option (unnecessary or even intrusive).
   832 
   833 * Antiquotation @{lemma A method} proves proposition A by the given
   834 method (either a method name or a method name plus (optional) method
   835 arguments in parentheses) and prints A just like @{prop A}.
   836 
   837 
   838 *** HOL ***
   839 
   840 * New primrec package.  Specification syntax conforms in style to
   841 definition/function/....  No separate induction rule is provided.  The
   842 "primrec" command distinguishes old-style and new-style specifications
   843 by syntax.  The former primrec package is now named OldPrimrecPackage.
   844 When adjusting theories, beware: constants stemming from new-style
   845 primrec specifications have authentic syntax.
   846 
   847 * Metis prover is now an order of magnitude faster, and also works
   848 with multithreading.
   849 
   850 * Metis: the maximum number of clauses that can be produced from a
   851 theorem is now given by the attribute max_clauses.  Theorems that
   852 exceed this number are ignored, with a warning printed.
   853 
   854 * Sledgehammer no longer produces structured proofs by default. To
   855 enable, declare [[sledgehammer_full = true]].  Attributes
   856 reconstruction_modulus, reconstruction_sorts renamed
   857 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   858 
   859 * Method "induct_scheme" derives user-specified induction rules
   860 from well-founded induction and completeness of patterns. This factors
   861 out some operations that are done internally by the function package
   862 and makes them available separately.  See
   863 src/HOL/ex/Induction_Scheme.thy for examples.
   864 
   865 * More flexible generation of measure functions for termination
   866 proofs: Measure functions can be declared by proving a rule of the
   867 form "is_measure f" and giving it the [measure_function] attribute.
   868 The "is_measure" predicate is logically meaningless (always true), and
   869 just guides the heuristic.  To find suitable measure functions, the
   870 termination prover sets up the goal "is_measure ?f" of the appropriate
   871 type and generates all solutions by prolog-style backwards proof using
   872 the declared rules.
   873 
   874 This setup also deals with rules like 
   875 
   876   "is_measure f ==> is_measure (list_size f)"
   877 
   878 which accommodates nested datatypes that recurse through lists.
   879 Similar rules are predeclared for products and option types.
   880 
   881 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   882 
   883   INCOMPATIBILITIES:
   884 
   885   - Definitions of overloaded constants on sets have to be replaced by
   886     definitions on => and bool.
   887 
   888   - Some definitions of overloaded operators on sets can now be proved
   889     using the definitions of the operators on => and bool.  Therefore,
   890     the following theorems have been renamed:
   891 
   892       subset_def   -> subset_eq
   893       psubset_def  -> psubset_eq
   894       set_diff_def -> set_diff_eq
   895       Compl_def    -> Compl_eq
   896       Sup_set_def  -> Sup_set_eq
   897       Inf_set_def  -> Inf_set_eq
   898       sup_set_def  -> sup_set_eq
   899       inf_set_def  -> inf_set_eq
   900 
   901   - Due to the incompleteness of the HO unification algorithm, some
   902     rules such as subst may require manual instantiation, if some of
   903     the unknowns in the rule is a set.
   904 
   905   - Higher order unification and forward proofs:
   906     The proof pattern
   907 
   908       have "P (S::'a set)" <...>
   909       then have "EX S. P S" ..
   910 
   911     no longer works (due to the incompleteness of the HO unification
   912     algorithm) and must be replaced by the pattern
   913 
   914       have "EX S. P S"
   915       proof
   916         show "P S" <...>
   917       qed
   918 
   919   - Calculational reasoning with subst (or similar rules):
   920     The proof pattern
   921 
   922       have "P (S::'a set)" <...>
   923       also have "S = T" <...>
   924       finally have "P T" .
   925 
   926     no longer works (for similar reasons as the previous example) and
   927     must be replaced by something like
   928 
   929       have "P (S::'a set)" <...>
   930       moreover have "S = T" <...>
   931       ultimately have "P T" by simp
   932 
   933   - Tactics or packages written in ML code:
   934     Code performing pattern matching on types via
   935 
   936       Type ("set", [T]) => ...
   937 
   938     must be rewritten. Moreover, functions like strip_type or
   939     binder_types no longer return the right value when applied to a
   940     type of the form
   941 
   942       T1 => ... => Tn => U => bool
   943 
   944     rather than
   945 
   946       T1 => ... => Tn => U set
   947 
   948 * Merged theories Wellfounded_Recursion, Accessible_Part and
   949 Wellfounded_Relations to theory Wellfounded.
   950 
   951 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   952 
   953 * Class finite no longer treats UNIV as class parameter.  Use class
   954 enum from theory Library/Enum instead to achieve a similar effect.
   955 INCOMPATIBILITY.
   956 
   957 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   958 and "Cons".  INCOMPATIBILITY.
   959 
   960 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   961 Potential INCOMPATIBILITY.
   962 
   963 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   964 injective_fst_snd removed, use split_eta and prod_eqI instead.
   965 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   966 
   967 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   968 the same name in theory Orderings:
   969 
   970   less_trans
   971   less_linear
   972   le_imp_less_or_eq
   973   le_less_trans
   974   less_le_trans
   975   less_not_sym
   976   less_asym
   977 
   978 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   979 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   980 and different variable names.
   981 
   982 * Library/Option_ord.thy: Canonical order on option type.
   983 
   984 * Library/RBT.thy: Red-black trees, an efficient implementation of
   985 finite maps.
   986 
   987 * Library/Countable.thy: Type class for countable types.
   988 
   989 * Theory Int: The representation of numerals has changed.  The infix
   990 operator BIT and the bit datatype with constructors B0 and B1 have
   991 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   992 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   993 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   994 accordingly.
   995 
   996 * Theory Nat: definition of <= and < on natural numbers no longer
   997 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   998 le_def and less_def have disappeared.  Consider lemmas not_less
   999 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1000 
  1001 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1002 (whose purpose mainly is for various fold_set functionals) have been
  1003 abandoned in favor of the existing algebraic classes
  1004 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1005 lower_semilattice (resp. upper_semilattice) and linorder.
  1006 INCOMPATIBILITY.
  1007 
  1008 * Theory Transitive_Closure: induct and cases rules now declare proper
  1009 case_names ("base" and "step").  INCOMPATIBILITY.
  1010 
  1011 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1012 lattices.  The form set-specific version is available as
  1013 Inductive.lfp_ordinal_induct_set.
  1014 
  1015 * Renamed theorems "power.simps" to "power_int.simps".
  1016 INCOMPATIBILITY.
  1017 
  1018 * Class semiring_div provides basic abstract properties of semirings
  1019 with division and modulo operations.  Subsumes former class dvd_mod.
  1020 
  1021 * Merged theories IntDef, Numeral and IntArith into unified theory
  1022 Int.  INCOMPATIBILITY.
  1023 
  1024 * Theory Library/Code_Index: type "index" now represents natural
  1025 numbers rather than integers.  INCOMPATIBILITY.
  1026 
  1027 * New class "uminus" with operation "uminus" (split of from class
  1028 "minus" which now only has operation "minus", binary).
  1029 INCOMPATIBILITY.
  1030 
  1031 * Constants "card", "internal_split", "option_map" now with authentic
  1032 syntax.  INCOMPATIBILITY.
  1033 
  1034 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1035 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1036 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1037 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1038 Sup_set_def, le_def, less_def, option_map_def now with object
  1039 equality.  INCOMPATIBILITY.
  1040 
  1041 * Records. Removed K_record, and replaced it by pure lambda term
  1042 %x. c. The simplifier setup is now more robust against eta expansion.
  1043 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1044 
  1045 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1046 
  1047 * Library/ListVector: new theory of arithmetic vector operations.
  1048 
  1049 * Library/Order_Relation: new theory of various orderings as sets of
  1050 pairs.  Defines preorders, partial orders, linear orders and
  1051 well-orders on sets and on types.
  1052 
  1053 
  1054 *** ZF ***
  1055 
  1056 * Renamed some theories to allow to loading both ZF and HOL in the
  1057 same session:
  1058 
  1059   Datatype  -> Datatype_ZF
  1060   Inductive -> Inductive_ZF
  1061   Int       -> Int_ZF
  1062   IntDiv    -> IntDiv_ZF
  1063   Nat       -> Nat_ZF
  1064   List      -> List_ZF
  1065   Main      -> Main_ZF
  1066 
  1067 INCOMPATIBILITY: ZF theories that import individual theories below
  1068 Main might need to be adapted.  Regular theory Main is still
  1069 available, as trivial extension of Main_ZF.
  1070 
  1071 
  1072 *** ML ***
  1073 
  1074 * ML within Isar: antiquotation @{const name} or @{const
  1075 name(typargs)} produces statically-checked Const term.
  1076 
  1077 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1078 (of the same name).  Removed obsolete print command.
  1079 
  1080 * Removed obsolete "use_legacy_bindings" function.
  1081 
  1082 * The ``print mode'' is now a thread-local value derived from a global
  1083 template (the former print_mode reference), thus access becomes
  1084 non-critical.  The global print_mode reference is for session
  1085 management only; user-code should use print_mode_value,
  1086 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1087 
  1088 * Functions system/system_out provide a robust way to invoke external
  1089 shell commands, with propagation of interrupts (requires Poly/ML
  1090 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1091 
  1092 
  1093 *** System ***
  1094 
  1095 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1096 in accordance with Proof General 3.7, which prefers GNU emacs.
  1097 
  1098 * isatool tty runs Isabelle process with plain tty interaction;
  1099 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1100 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1101 
  1102 * isatool browser now works with Cygwin as well, using general
  1103 "javapath" function defined in Isabelle process environment.
  1104 
  1105 * YXML notation provides a simple and efficient alternative to
  1106 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1107 isatool yxml as described in the Isabelle system manual.
  1108 
  1109 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1110 provides general wrapper for managing an Isabelle process in a robust
  1111 fashion, with ``cooked'' output from stdin/stderr.
  1112 
  1113 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1114 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1115 
  1116 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1117 way of changing the user's settings is via
  1118 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1119 script.
  1120 
  1121 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1122 cores of the underlying machine, which is a good starting point for
  1123 optimal performance tuning.  The corresponding usedir option -M allows
  1124 "max" as an alias for "0".  WARNING: does not work on certain versions
  1125 of Mac OS (with Poly/ML 5.1).
  1126 
  1127 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1128 adverse effect of Isabelle flooding interactive front-ends (notably
  1129 ProofGeneral / XEmacs).
  1130 
  1131 
  1132 
  1133 New in Isabelle2007 (November 2007)
  1134 -----------------------------------
  1135 
  1136 *** General ***
  1137 
  1138 * More uniform information about legacy features, notably a
  1139 warning/error of "Legacy feature: ...", depending on the state of the
  1140 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1141 legacy features will disappear eventually.
  1142 
  1143 * Theory syntax: the header format ``theory A = B + C:'' has been
  1144 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1145 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1146 
  1147 * Theory syntax: the old non-Isar theory file format has been
  1148 discontinued altogether.  Note that ML proof scripts may still be used
  1149 with Isar theories; migration is usually quite simple with the ML
  1150 function use_legacy_bindings.  INCOMPATIBILITY.
  1151 
  1152 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1153 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1154 quotes.
  1155 
  1156 * Theory loader: be more serious about observing the static theory
  1157 header specifications (including optional directories), but not the
  1158 accidental file locations of previously successful loads.  The strict
  1159 update policy of former update_thy is now already performed by
  1160 use_thy, so the former has been removed; use_thys updates several
  1161 theories simultaneously, just as 'imports' within a theory header
  1162 specification, but without merging the results.  Potential
  1163 INCOMPATIBILITY: may need to refine theory headers and commands
  1164 ROOT.ML which depend on load order.
  1165 
  1166 * Theory loader: optional support for content-based file
  1167 identification, instead of the traditional scheme of full physical
  1168 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1169 (cf. the system manual).  The new scheme allows to work with
  1170 non-finished theories in persistent session images, such that source
  1171 files may be moved later on without requiring reloads.
  1172 
  1173 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1174 file (with the same base name as the theory) are considered a legacy
  1175 feature, which will disappear eventually. Even now, the theory loader
  1176 no longer maintains dependencies on such files.
  1177 
  1178 * Syntax: the scope for resolving ambiguities via type-inference is
  1179 now limited to individual terms, instead of whole simultaneous
  1180 specifications as before. This greatly reduces the complexity of the
  1181 syntax module and improves flexibility by separating parsing and
  1182 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1183 'fixes' etc.) are required in rare situations.
  1184 
  1185 * Syntax: constants introduced by new-style packages ('definition',
  1186 'abbreviation' etc.) are passed through the syntax module in
  1187 ``authentic mode''. This means that associated mixfix annotations
  1188 really stick to such constants, independently of potential name space
  1189 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1190 trees are represented slightly differently, may need to adapt syntax
  1191 translations accordingly. Use CONST marker in 'translations' and
  1192 @{const_syntax} antiquotation in 'parse_translation' etc.
  1193 
  1194 * Legacy goal package: reduced interface to the bare minimum required
  1195 to keep existing proof scripts running.  Most other user-level
  1196 functions are now part of the OldGoals structure, which is *not* open
  1197 by default (consider isatool expandshort before open OldGoals).
  1198 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1199 these tend to cause confusion about the actual goal (!) context being
  1200 used here, which is not necessarily the same as the_context().
  1201 
  1202 * Command 'find_theorems': supports "*" wild-card in "name:"
  1203 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1204 support a specific search form (see ProofGeneral/CHANGES).
  1205 
  1206 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1207 by default, which means that "prems" (and also "fixed variables") are
  1208 suppressed from proof state output.  Note that the ProofGeneral
  1209 settings mechanism allows to change and save options persistently, but
  1210 older versions of Isabelle will fail to start up if a negative prems
  1211 limit is imposed.
  1212 
  1213 * Local theory targets may be specified by non-nested blocks of
  1214 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1215 contain definitions, theorems etc., including any derived mechanism
  1216 that has been implemented on top of these primitives.  This concept
  1217 generalizes the existing ``theorem (in ...)'' towards more versatility
  1218 and scalability.
  1219 
  1220 * Proof General interface: proper undo of final 'end' command;
  1221 discontinued Isabelle/classic mode (ML proof scripts).
  1222 
  1223 
  1224 *** Document preparation ***
  1225 
  1226 * Added antiquotation @{theory name} which prints the given name,
  1227 after checking that it refers to a valid ancestor theory in the
  1228 current context.
  1229 
  1230 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1231 check the given source text as ML type/structure, printing verbatim.
  1232 
  1233 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1234 "c args == rhs" given in the current context.  (Any number of
  1235 arguments may be given on the LHS.)
  1236 
  1237 
  1238 *** Pure ***
  1239 
  1240 * The 'class' package offers a combination of axclass and locale to
  1241 achieve Haskell-like type classes in Isabelle.  Definitions and
  1242 theorems within a class context produce both relative results (with
  1243 implicit parameters according to the locale context), and polymorphic
  1244 constants with qualified polymorphism (according to the class
  1245 context).  Within the body context of a 'class' target, a separate
  1246 syntax layer ("user space type system") takes care of converting
  1247 between global polymorphic consts and internal locale representation.
  1248 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1249 "isatool doc classes" provides a tutorial.
  1250 
  1251 * Generic code generator framework allows to generate executable
  1252 code for ML and Haskell (including Isabelle classes).  A short usage
  1253 sketch:
  1254 
  1255     internal compilation:
  1256         export_code <list of constants (term syntax)> in SML
  1257     writing SML code to a file:
  1258         export_code <list of constants (term syntax)> in SML <filename>
  1259     writing OCaml code to a file:
  1260         export_code <list of constants (term syntax)> in OCaml <filename>
  1261     writing Haskell code to a bunch of files:
  1262         export_code <list of constants (term syntax)> in Haskell <filename>
  1263 
  1264     evaluating closed propositions to True/False using code generation:
  1265         method ``eval''
  1266 
  1267 Reasonable default setup of framework in HOL.
  1268 
  1269 Theorem attributs for selecting and transforming function equations theorems:
  1270 
  1271     [code fun]:        select a theorem as function equation for a specific constant
  1272     [code fun del]:    deselect a theorem as function equation for a specific constant
  1273     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1274     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1275 
  1276 User-defined serializations (target in {SML, OCaml, Haskell}):
  1277 
  1278     code_const <and-list of constants (term syntax)>
  1279       {(target) <and-list of const target syntax>}+
  1280 
  1281     code_type <and-list of type constructors>
  1282       {(target) <and-list of type target syntax>}+
  1283 
  1284     code_instance <and-list of instances>
  1285       {(target)}+
  1286         where instance ::= <type constructor> :: <class>
  1287 
  1288     code_class <and_list of classes>
  1289       {(target) <and-list of class target syntax>}+
  1290         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1291 
  1292 code_instance and code_class only are effective to target Haskell.
  1293 
  1294 For example usage see src/HOL/ex/Codegenerator.thy and
  1295 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1296 generation from Isabelle/HOL theories is available via "isatool doc
  1297 codegen".
  1298 
  1299 * Code generator: consts in 'consts_code' Isar commands are now
  1300 referred to by usual term syntax (including optional type
  1301 annotations).
  1302 
  1303 * Command 'no_translations' removes translation rules from theory
  1304 syntax.
  1305 
  1306 * Overloaded definitions are now actually checked for acyclic
  1307 dependencies.  The overloading scheme is slightly more general than
  1308 that of Haskell98, although Isabelle does not demand an exact
  1309 correspondence to type class and instance declarations.
  1310 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1311 exotic versions of overloading -- at the discretion of the user!
  1312 
  1313 Polymorphic constants are represented via type arguments, i.e. the
  1314 instantiation that matches an instance against the most general
  1315 declaration given in the signature.  For example, with the declaration
  1316 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1317 as c(nat).  Overloading is essentially simultaneous structural
  1318 recursion over such type arguments.  Incomplete specification patterns
  1319 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1320 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1321 Command 'print_theory' outputs the normalized system of recursive
  1322 equations, see section "definitions".
  1323 
  1324 * Configuration options are maintained within the theory or proof
  1325 context (with name and type bool/int/string), providing a very simple
  1326 interface to a poor-man's version of general context data.  Tools may
  1327 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1328 these values using Config.get etc.  Users may change options via an
  1329 associated attribute of the same name.  This form of context
  1330 declaration works particularly well with commands 'declare' or
  1331 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1332 very easy to avoid global references, which would not observe Isar
  1333 toplevel undo/redo and fail to work with multithreading.
  1334 
  1335 Various global ML references of Pure and HOL have been turned into
  1336 configuration options:
  1337 
  1338   Unify.search_bound		unify_search_bound
  1339   Unify.trace_bound		unify_trace_bound
  1340   Unify.trace_simp		unify_trace_simp
  1341   Unify.trace_types		unify_trace_types
  1342   Simplifier.simp_depth_limit	simp_depth_limit
  1343   Blast.depth_limit		blast_depth_limit
  1344   DatatypeProp.dtK		datatype_distinctness_limit
  1345   fast_arith_neq_limit  	fast_arith_neq_limit
  1346   fast_arith_split_limit	fast_arith_split_limit
  1347 
  1348 * Named collections of theorems may be easily installed as context
  1349 data using the functor NamedThmsFun (see also
  1350 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1351 attributes; there is also a toplevel print command.  This facility is
  1352 just a common case of general context data, which is the preferred way
  1353 for anything more complex than just a list of facts in canonical
  1354 order.
  1355 
  1356 * Isar: command 'declaration' augments a local theory by generic
  1357 declaration functions written in ML.  This enables arbitrary content
  1358 being added to the context, depending on a morphism that tells the
  1359 difference of the original declaration context wrt. the application
  1360 context encountered later on.
  1361 
  1362 * Isar: proper interfaces for simplification procedures.  Command
  1363 'simproc_setup' declares named simprocs (with match patterns, and body
  1364 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1365 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1366 
  1367 * Isar: an extra pair of brackets around attribute declarations
  1368 abbreviates a theorem reference involving an internal dummy fact,
  1369 which will be ignored later --- only the effect of the attribute on
  1370 the background context will persist.  This form of in-place
  1371 declarations is particularly useful with commands like 'declare' and
  1372 'using', for example ``have A using [[simproc a]] by simp''.
  1373 
  1374 * Isar: method "assumption" (and implicit closing of subproofs) now
  1375 takes simple non-atomic goal assumptions into account: after applying
  1376 an assumption as a rule the resulting subgoals are solved by atomic
  1377 assumption steps.  This is particularly useful to finish 'obtain'
  1378 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1379 without referring to the original premise "!!x. P x ==> thesis" in the
  1380 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1381 more permissive.
  1382 
  1383 * Isar: implicit use of prems from the Isar proof context is
  1384 considered a legacy feature.  Common applications like ``have A .''
  1385 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1386 referencing facts explicitly here improves readability and
  1387 maintainability of proof texts.
  1388 
  1389 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1390 the obtained context from the course of reasoning!  For example:
  1391 
  1392   assume "EX x y. A x & B y"   -- "any previous fact"
  1393   then guess x and y by clarify
  1394 
  1395 This technique is potentially adventurous, depending on the facts and
  1396 proof tools being involved here.
  1397 
  1398 * Isar: known facts from the proof context may be specified as literal
  1399 propositions, using ASCII back-quote syntax.  This works wherever
  1400 named facts used to be allowed so far, in proof commands, proof
  1401 methods, attributes etc.  Literal facts are retrieved from the context
  1402 according to unification of type and term parameters.  For example,
  1403 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1404 theorems in the current context, then these are valid literal facts:
  1405 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1406 
  1407 There is also a proof method "fact" which does the same composition
  1408 for explicit goal states, e.g. the following proof texts coincide with
  1409 certain special cases of literal facts:
  1410 
  1411   have "A" by fact                 ==  note `A`
  1412   have "A ==> B" by fact           ==  note `A ==> B`
  1413   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1414   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1415 
  1416 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1417 outer syntax.  Thus symbolic identifiers may be used without
  1418 additional white space in declarations like this: ``assume *: A''.
  1419 
  1420 * Isar: 'print_facts' prints all local facts of the current context,
  1421 both named and unnamed ones.
  1422 
  1423 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1424 
  1425   def x == "t" and y == "u"
  1426 
  1427 * Isar: added command 'unfolding', which is structurally similar to
  1428 'using', but affects both the goal state and facts by unfolding given
  1429 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1430 'unfolded' attribute may be replaced by first-class proof text.
  1431 
  1432 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1433 and command 'unfolding' now all support object-level equalities
  1434 (potentially conditional).  The underlying notion of rewrite rule is
  1435 analogous to the 'rule_format' attribute, but *not* that of the
  1436 Simplifier (which is usually more generous).
  1437 
  1438 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1439 premises of a theorem by n. Useful in conjunction with drule.
  1440 
  1441 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1442 method expression within a sandbox consisting of the first N
  1443 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1444 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1445 simplifies all new goals that emerge from applying rule foo to the
  1446 originally first one.
  1447 
  1448 * Isar: schematic goals are no longer restricted to higher-order
  1449 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1450 expected.
  1451 
  1452 * Isar: the conclusion of a long theorem statement is now either
  1453 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1454 (essentially a disjunction of cases with local parameters and
  1455 assumptions).  The latter allows to express general elimination rules
  1456 adequately; in this notation common elimination rules look like this:
  1457 
  1458   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1459     assumes "EX x. P x"
  1460     obtains x where "P x"
  1461 
  1462   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1463     assumes "A & B"
  1464     obtains A and B
  1465 
  1466   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1467     assumes "A | B"
  1468     obtains
  1469       A
  1470     | B
  1471 
  1472 The subsequent classical rules even refer to the formal "thesis"
  1473 explicitly:
  1474 
  1475   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1476     obtains "~ thesis"
  1477 
  1478   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1479     obtains "thesis ==> something"
  1480 
  1481 The actual proof of an 'obtains' statement is analogous to that of the
  1482 Isar proof element 'obtain', only that there may be several cases.
  1483 Optional case names may be specified in parentheses; these will be
  1484 available both in the present proof and as annotations in the
  1485 resulting rule, for later use with the 'cases' method (cf. attribute
  1486 case_names).
  1487 
  1488 * Isar: the assumptions of a long theorem statement are available as
  1489 "assms" fact in the proof context.  This is more appropriate than the
  1490 (historical) "prems", which refers to all assumptions of the current
  1491 context, including those from the target locale, proof body etc.
  1492 
  1493 * Isar: 'print_statement' prints theorems from the current theory or
  1494 proof context in long statement form, according to the syntax of a
  1495 top-level lemma.
  1496 
  1497 * Isar: 'obtain' takes an optional case name for the local context
  1498 introduction rule (default "that").
  1499 
  1500 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1501 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1502 to occur.
  1503 
  1504 * Pure: syntax "CONST name" produces a fully internalized constant
  1505 according to the current context.  This is particularly useful for
  1506 syntax translations that should refer to internal constant
  1507 representations independently of name spaces.
  1508 
  1509 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1510 instead of "FOO ". This allows multiple binder declarations to coexist
  1511 in the same context.  INCOMPATIBILITY.
  1512 
  1513 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1514 primitive that also works in a locale context (both for constants and
  1515 fixed variables). Type declaration and internal syntactic representation
  1516 of given constants retrieved from the context. Likewise, the
  1517 'no_notation' command allows to remove given syntax annotations from the
  1518 current context.
  1519 
  1520 * Isar/locales: new derived specification elements 'axiomatization',
  1521 'definition', 'abbreviation', which support type-inference, admit
  1522 object-level specifications (equality, equivalence).  See also the
  1523 isar-ref manual.  Examples:
  1524 
  1525   axiomatization
  1526     eq  (infix "===" 50) where
  1527     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1528 
  1529   definition "f x y = x + y + 1"
  1530   definition g where "g x = f x x"
  1531 
  1532   abbreviation
  1533     neq  (infix "=!=" 50) where
  1534     "x =!= y == ~ (x === y)"
  1535 
  1536 These specifications may be also used in a locale context.  Then the
  1537 constants being introduced depend on certain fixed parameters, and the
  1538 constant name is qualified by the locale base name.  An internal
  1539 abbreviation takes care for convenient input and output, making the
  1540 parameters implicit and using the original short name.  See also
  1541 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1542 entities from a monomorphic theory.
  1543 
  1544 Presently, abbreviations are only available 'in' a target locale, but
  1545 not inherited by general import expressions.  Also note that
  1546 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1547 'translations' in common applications.  The "no_abbrevs" print mode
  1548 prevents folding of abbreviations in term output.
  1549 
  1550 Concrete syntax is attached to specified constants in internal form,
  1551 independently of name spaces.  The parse tree representation is
  1552 slightly different -- use 'notation' instead of raw 'syntax', and
  1553 'translations' with explicit "CONST" markup to accommodate this.
  1554 
  1555 * Pure/Isar: unified syntax for new-style specification mechanisms
  1556 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1557 full type inference and dummy patterns ("_").  For example:
  1558 
  1559   definition "K x _ = x"
  1560 
  1561   inductive conj for A B
  1562   where "A ==> B ==> conj A B"
  1563 
  1564 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1565 the current context.  Print mode "no_abbrevs" prevents inversion of
  1566 abbreviations on output.
  1567 
  1568 * Isar/locales: improved parameter handling: use of locales "var" and
  1569 "struct" no longer necessary; - parameter renamings are no longer
  1570 required to be injective.  For example, this allows to define
  1571 endomorphisms as locale endom = homom mult mult h.
  1572 
  1573 * Isar/locales: changed the way locales with predicates are defined.
  1574 Instead of accumulating the specification, the imported expression is
  1575 now an interpretation.  INCOMPATIBILITY: different normal form of
  1576 locale expressions.  In particular, in interpretations of locales with
  1577 predicates, goals repesenting already interpreted fragments are not
  1578 removed automatically.  Use methods `intro_locales' and
  1579 `unfold_locales'; see below.
  1580 
  1581 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1582 provide backward reasoning on locales predicates.  The methods are
  1583 aware of interpretations and discharge corresponding goals.
  1584 `intro_locales' is less aggressive then `unfold_locales' and does not
  1585 unfold predicates to assumptions.
  1586 
  1587 * Isar/locales: the order in which locale fragments are accumulated
  1588 has changed.  This enables to override declarations from fragments due
  1589 to interpretations -- for example, unwanted simp rules.
  1590 
  1591 * Isar/locales: interpretation in theories and proof contexts has been
  1592 extended.  One may now specify (and prove) equations, which are
  1593 unfolded in interpreted theorems.  This is useful for replacing
  1594 defined concepts (constants depending on locale parameters) by
  1595 concepts already existing in the target context.  Example:
  1596 
  1597   interpretation partial_order ["op <= :: [int, int] => bool"]
  1598     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1599 
  1600 Typically, the constant `partial_order.less' is created by a
  1601 definition specification element in the context of locale
  1602 partial_order.
  1603 
  1604 * Method "induct": improved internal context management to support
  1605 local fixes and defines on-the-fly. Thus explicit meta-level
  1606 connectives !!  and ==> are rarely required anymore in inductive goals
  1607 (using object-logic connectives for this purpose has been long
  1608 obsolete anyway). Common proof patterns are explained in
  1609 src/HOL/Induct/Common_Patterns.thy, see also
  1610 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1611 examples.
  1612 
  1613 * Method "induct": improved handling of simultaneous goals. Instead of
  1614 introducing object-level conjunction, the statement is now split into
  1615 several conclusions, while the corresponding symbolic cases are nested
  1616 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1617 see src/HOL/Induct/Common_Patterns.thy, for example.
  1618 
  1619 * Method "induct": mutual induction rules are now specified as a list
  1620 of rule sharing the same induction cases. HOL packages usually provide
  1621 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1622 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1623 mutual induction rules differently, i.e. like this:
  1624 
  1625   (induct rule: foo_bar.inducts)
  1626   (induct set: foo bar)
  1627   (induct pred: foo bar)
  1628   (induct type: foo bar)
  1629 
  1630 The ML function ProjectRule.projections turns old-style rules into the
  1631 new format.
  1632 
  1633 * Method "coinduct": dual of induction, see
  1634 src/HOL/Library/Coinductive_List.thy for various examples.
  1635 
  1636 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1637 considered a legacy feature.
  1638 
  1639 * Attribute "symmetric" produces result with standardized schematic
  1640 variables (index 0).  Potential INCOMPATIBILITY.
  1641 
  1642 * Simplifier: by default the simplifier trace only shows top level
  1643 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1644 default. Thus there is less danger of being flooded by the trace. The
  1645 trace indicates where parts have been suppressed.
  1646   
  1647 * Provers/classical: removed obsolete classical version of elim_format
  1648 attribute; classical elim/dest rules are now treated uniformly when
  1649 manipulating the claset.
  1650 
  1651 * Provers/classical: stricter checks to ensure that supplied intro,
  1652 dest and elim rules are well-formed; dest and elim rules must have at
  1653 least one premise.
  1654 
  1655 * Provers/classical: attributes dest/elim/intro take an optional
  1656 weight argument for the rule (just as the Pure versions).  Weights are
  1657 ignored by automated tools, but determine the search order of single
  1658 rule steps.
  1659 
  1660 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1661 where the body does not mention the bound variable.  Note that dummy
  1662 patterns implicitly depend on their context of bounds, which makes
  1663 "{_. _}" match any set comprehension as expected.  Potential
  1664 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1665 constant "_idtdummy" in the binding position.
  1666 
  1667 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1668 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1669 for example "A -> B" => "Pi A (%_. B)".
  1670 
  1671 * Pure: 'class_deps' command visualizes the subclass relation, using
  1672 the graph browser tool.
  1673 
  1674 * Pure: 'print_theory' now suppresses certain internal declarations by
  1675 default; use '!' option for full details.
  1676 
  1677 
  1678 *** HOL ***
  1679 
  1680 * Method "metis" proves goals by applying the Metis general-purpose
  1681 resolution prover (see also http://gilith.com/software/metis/).
  1682 Examples are in the directory MetisExamples.  WARNING: the
  1683 Isabelle/HOL-Metis integration does not yet work properly with
  1684 multi-threading.
  1685   
  1686 * Command 'sledgehammer' invokes external automatic theorem provers as
  1687 background processes.  It generates calls to the "metis" method if
  1688 successful. These can be pasted into the proof.  Users do not have to
  1689 wait for the automatic provers to return.  WARNING: does not really
  1690 work with multi-threading.
  1691 
  1692 * New "auto_quickcheck" feature tests outermost goal statements for
  1693 potential counter-examples.  Controlled by ML references
  1694 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1695 5000 milliseconds).  Fails silently if statements is outside of
  1696 executable fragment, or any other codgenerator problem occurs.
  1697 
  1698 * New constant "undefined" with axiom "undefined x = undefined".
  1699 
  1700 * Added class "HOL.eq", allowing for code generation with polymorphic
  1701 equality.
  1702 
  1703 * Some renaming of class constants due to canonical name prefixing in
  1704 the new 'class' package:
  1705 
  1706     HOL.abs ~> HOL.abs_class.abs
  1707     HOL.divide ~> HOL.divide_class.divide
  1708     0 ~> HOL.zero_class.zero
  1709     1 ~> HOL.one_class.one
  1710     op + ~> HOL.plus_class.plus
  1711     op - ~> HOL.minus_class.minus
  1712     uminus ~> HOL.minus_class.uminus
  1713     op * ~> HOL.times_class.times
  1714     op < ~> HOL.ord_class.less
  1715     op <= > HOL.ord_class.less_eq
  1716     Nat.power ~> Power.power_class.power
  1717     Nat.size ~> Nat.size_class.size
  1718     Numeral.number_of ~> Numeral.number_class.number_of
  1719     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1720     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1721     Orderings.min ~> Orderings.ord_class.min
  1722     Orderings.max ~> Orderings.ord_class.max
  1723     Divides.op div ~> Divides.div_class.div
  1724     Divides.op mod ~> Divides.div_class.mod
  1725     Divides.op dvd ~> Divides.div_class.dvd
  1726 
  1727 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1728 
  1729 a) User-defined constants using any of the names "plus", "minus",
  1730 "times", "less" or "less_eq". The standard syntax translations for
  1731 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1732 names.
  1733 
  1734 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1735 INCOMPATIBILITY: use more specific names.
  1736 
  1737 c) Permutative equations (e.g. "a + b = b + a")
  1738 Since the change of names also changes the order of terms, permutative
  1739 rewrite rules may get applied in a different order. Experience shows
  1740 that this is rarely the case (only two adaptions in the whole Isabelle
  1741 distribution).  INCOMPATIBILITY: rewrite proofs
  1742 
  1743 d) ML code directly refering to constant names
  1744 This in general only affects hand-written proof tactics, simprocs and
  1745 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1746 Consider using @{const_name} antiquotation.
  1747 
  1748 * New class "default" with associated constant "default".
  1749 
  1750 * Function "sgn" is now overloaded and available on int, real, complex
  1751 (and other numeric types), using class "sgn".  Two possible defs of
  1752 sgn are given as equational assumptions in the classes sgn_if and
  1753 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1754 INCOMPATIBILITY.
  1755 
  1756 * Locale "partial_order" now unified with class "order" (cf. theory
  1757 Orderings), added parameter "less".  INCOMPATIBILITY.
  1758 
  1759 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1760 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1761 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1762 
  1763 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1764 changed order of proof goals in instance proofs.
  1765 
  1766 * The transitivity reasoner for partial and linear orders is set up
  1767 for classes "order" and "linorder".  Instances of the reasoner are available
  1768 in all contexts importing or interpreting the corresponding locales.
  1769 Method "order" invokes the reasoner separately; the reasoner
  1770 is also integrated with the Simplifier as a solver.  Diagnostic
  1771 command 'print_orders' shows the available instances of the reasoner
  1772 in the current context.
  1773 
  1774 * Localized monotonicity predicate in theory "Orderings"; integrated
  1775 lemmas max_of_mono and min_of_mono with this predicate.
  1776 INCOMPATIBILITY.
  1777 
  1778 * Formulation of theorem "dense" changed slightly due to integration
  1779 with new class dense_linear_order.
  1780 
  1781 * Uniform lattice theory development in HOL.
  1782 
  1783     constants "meet" and "join" now named "inf" and "sup"
  1784     constant "Meet" now named "Inf"
  1785 
  1786     classes "meet_semilorder" and "join_semilorder" now named
  1787       "lower_semilattice" and "upper_semilattice"
  1788     class "lorder" now named "lattice"
  1789     class "comp_lat" now named "complete_lattice"
  1790 
  1791     Instantiation of lattice classes allows explicit definitions
  1792     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1793 
  1794   INCOMPATIBILITY.  Theorem renames:
  1795 
  1796     meet_left_le            ~> inf_le1
  1797     meet_right_le           ~> inf_le2
  1798     join_left_le            ~> sup_ge1
  1799     join_right_le           ~> sup_ge2
  1800     meet_join_le            ~> inf_sup_ord
  1801     le_meetI                ~> le_infI
  1802     join_leI                ~> le_supI
  1803     le_meet                 ~> le_inf_iff
  1804     le_join                 ~> ge_sup_conv
  1805     meet_idempotent         ~> inf_idem
  1806     join_idempotent         ~> sup_idem
  1807     meet_comm               ~> inf_commute
  1808     join_comm               ~> sup_commute
  1809     meet_leI1               ~> le_infI1
  1810     meet_leI2               ~> le_infI2
  1811     le_joinI1               ~> le_supI1
  1812     le_joinI2               ~> le_supI2
  1813     meet_assoc              ~> inf_assoc
  1814     join_assoc              ~> sup_assoc
  1815     meet_left_comm          ~> inf_left_commute
  1816     meet_left_idempotent    ~> inf_left_idem
  1817     join_left_comm          ~> sup_left_commute
  1818     join_left_idempotent    ~> sup_left_idem
  1819     meet_aci                ~> inf_aci
  1820     join_aci                ~> sup_aci
  1821     le_def_meet             ~> le_iff_inf
  1822     le_def_join             ~> le_iff_sup
  1823     join_absorp2            ~> sup_absorb2
  1824     join_absorp1            ~> sup_absorb1
  1825     meet_absorp1            ~> inf_absorb1
  1826     meet_absorp2            ~> inf_absorb2
  1827     meet_join_absorp        ~> inf_sup_absorb
  1828     join_meet_absorp        ~> sup_inf_absorb
  1829     distrib_join_le         ~> distrib_sup_le
  1830     distrib_meet_le         ~> distrib_inf_le
  1831 
  1832     add_meet_distrib_left   ~> add_inf_distrib_left
  1833     add_join_distrib_left   ~> add_sup_distrib_left
  1834     is_join_neg_meet        ~> is_join_neg_inf
  1835     is_meet_neg_join        ~> is_meet_neg_sup
  1836     add_meet_distrib_right  ~> add_inf_distrib_right
  1837     add_join_distrib_right  ~> add_sup_distrib_right
  1838     add_meet_join_distribs  ~> add_sup_inf_distribs
  1839     join_eq_neg_meet        ~> sup_eq_neg_inf
  1840     meet_eq_neg_join        ~> inf_eq_neg_sup
  1841     add_eq_meet_join        ~> add_eq_inf_sup
  1842     meet_0_imp_0            ~> inf_0_imp_0
  1843     join_0_imp_0            ~> sup_0_imp_0
  1844     meet_0_eq_0             ~> inf_0_eq_0
  1845     join_0_eq_0             ~> sup_0_eq_0
  1846     neg_meet_eq_join        ~> neg_inf_eq_sup
  1847     neg_join_eq_meet        ~> neg_sup_eq_inf
  1848     join_eq_if              ~> sup_eq_if
  1849 
  1850     mono_meet               ~> mono_inf
  1851     mono_join               ~> mono_sup
  1852     meet_bool_eq            ~> inf_bool_eq
  1853     join_bool_eq            ~> sup_bool_eq
  1854     meet_fun_eq             ~> inf_fun_eq
  1855     join_fun_eq             ~> sup_fun_eq
  1856     meet_set_eq             ~> inf_set_eq
  1857     join_set_eq             ~> sup_set_eq
  1858     meet1_iff               ~> inf1_iff
  1859     meet2_iff               ~> inf2_iff
  1860     meet1I                  ~> inf1I
  1861     meet2I                  ~> inf2I
  1862     meet1D1                 ~> inf1D1
  1863     meet2D1                 ~> inf2D1
  1864     meet1D2                 ~> inf1D2
  1865     meet2D2                 ~> inf2D2
  1866     meet1E                  ~> inf1E
  1867     meet2E                  ~> inf2E
  1868     join1_iff               ~> sup1_iff
  1869     join2_iff               ~> sup2_iff
  1870     join1I1                 ~> sup1I1
  1871     join2I1                 ~> sup2I1
  1872     join1I1                 ~> sup1I1
  1873     join2I2                 ~> sup1I2
  1874     join1CI                 ~> sup1CI
  1875     join2CI                 ~> sup2CI
  1876     join1E                  ~> sup1E
  1877     join2E                  ~> sup2E
  1878 
  1879     is_meet_Meet            ~> is_meet_Inf
  1880     Meet_bool_def           ~> Inf_bool_def
  1881     Meet_fun_def            ~> Inf_fun_def
  1882     Meet_greatest           ~> Inf_greatest
  1883     Meet_lower              ~> Inf_lower
  1884     Meet_set_def            ~> Inf_set_def
  1885 
  1886     Sup_def                 ~> Sup_Inf
  1887     Sup_bool_eq             ~> Sup_bool_def
  1888     Sup_fun_eq              ~> Sup_fun_def
  1889     Sup_set_eq              ~> Sup_set_def
  1890 
  1891     listsp_meetI            ~> listsp_infI
  1892     listsp_meet_eq          ~> listsp_inf_eq
  1893 
  1894     meet_min                ~> inf_min
  1895     join_max                ~> sup_max
  1896 
  1897 * Added syntactic class "size"; overloaded constant "size" now has
  1898 type "'a::size ==> bool"
  1899 
  1900 * Internal reorganisation of `size' of datatypes: size theorems
  1901 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1902 simplification rules by default!); theorems "prod.size" now named
  1903 "*.size".
  1904 
  1905 * Class "div" now inherits from class "times" rather than "type".
  1906 INCOMPATIBILITY.
  1907 
  1908 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1909 Linorder etc.  have disappeared; operations defined in terms of
  1910 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1911 
  1912 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1913 
  1914 * HOL-Word: New extensive library and type for generic, fixed size
  1915 machine words, with arithemtic, bit-wise, shifting and rotating
  1916 operations, reflection into int, nat, and bool lists, automation for
  1917 linear arithmetic (by automatic reflection into nat or int), including
  1918 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1919 arithmetic type classes, supporting automatic simplification of
  1920 numerals on all operations.
  1921 
  1922 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1923 
  1924 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1925 
  1926 * Code generator library theories:
  1927   - Code_Integer represents HOL integers by big integer literals in target
  1928     languages.
  1929   - Code_Char represents HOL characters by character literals in target
  1930     languages.
  1931   - Code_Char_chr like Code_Char, but also offers treatment of character
  1932     codes; includes Code_Integer.
  1933   - Executable_Set allows to generate code for finite sets using lists.
  1934   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1935     denominator).
  1936   - Executable_Real implements a subset of real numbers, namly those
  1937     representable by rational numbers.
  1938   - Efficient_Nat implements natural numbers by integers, which in general will
  1939     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1940     includes Code_Integer.
  1941   - Code_Index provides an additional datatype index which is mapped to
  1942     target-language built-in integers.
  1943   - Code_Message provides an additional datatype message_string which is isomorphic to
  1944     strings; messages are mapped to target-language strings.
  1945 
  1946 * New package for inductive predicates
  1947 
  1948   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1949 
  1950     inductive
  1951       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1952       for z_1 :: U_1 and ... and z_n :: U_m
  1953     where
  1954       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1955     | ...
  1956 
  1957   with full support for type-inference, rather than
  1958 
  1959     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1960 
  1961     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1962     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1963 
  1964     inductive "s z_1 ... z_m"
  1965     intros
  1966       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1967       ...
  1968 
  1969   For backward compatibility, there is a wrapper allowing inductive
  1970   sets to be defined with the new package via
  1971 
  1972     inductive_set
  1973       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1974       for z_1 :: U_1 and ... and z_n :: U_m
  1975     where
  1976       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1977     | ...
  1978 
  1979   or
  1980 
  1981     inductive_set
  1982       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1983       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1984       for z_1 :: U_1 and ... and z_n :: U_m
  1985     where
  1986       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1987     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1988     | ...
  1989 
  1990   if the additional syntax "p ..." is required.
  1991 
  1992   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1993   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1994 
  1995   INCOMPATIBILITIES:
  1996 
  1997   - Since declaration and definition of inductive sets or predicates
  1998     is no longer separated, abbreviations involving the newly
  1999     introduced sets or predicates must be specified together with the
  2000     introduction rules after the 'where' keyword (see above), rather
  2001     than before the actual inductive definition.
  2002 
  2003   - The variables in induction and elimination rules are now
  2004     quantified in the order of their occurrence in the introduction
  2005     rules, rather than in alphabetical order. Since this may break
  2006     some proofs, these proofs either have to be repaired, e.g. by
  2007     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2008     statements of the form
  2009 
  2010       case (rule_i a_i_1 ... a_i_{k_i})
  2011 
  2012     or the old order of quantification has to be restored by explicitly adding
  2013     meta-level quantifiers in the introduction rules, i.e.
  2014 
  2015       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2016 
  2017   - The format of the elimination rules is now
  2018 
  2019       p z_1 ... z_m x_1 ... x_n ==>
  2020         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2021         ==> ... ==> P
  2022 
  2023     for predicates and
  2024 
  2025       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2026         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2027         ==> ... ==> P
  2028 
  2029     for sets rather than
  2030 
  2031       x : s z_1 ... z_m ==>
  2032         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2033         ==> ... ==> P
  2034 
  2035     This may require terms in goals to be expanded to n-tuples
  2036     (e.g. using case_tac or simplification with the split_paired_all
  2037     rule) before the above elimination rule is applicable.
  2038 
  2039   - The elimination or case analysis rules for (mutually) inductive
  2040     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2041     list of rules "p_1_..._p_k.elims" is no longer available.
  2042 
  2043 * New package "function"/"fun" for general recursive functions,
  2044 supporting mutual and nested recursion, definitions in local contexts,
  2045 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2046 for small examples, and the separate tutorial on the function
  2047 package. The old recdef "package" is still available as before, but
  2048 users are encouraged to use the new package.
  2049 
  2050 * Method "lexicographic_order" automatically synthesizes termination
  2051 relations as lexicographic combinations of size measures. 
  2052 
  2053 * Case-expressions allow arbitrary constructor-patterns (including
  2054 "_") and take their order into account, like in functional
  2055 programming.  Internally, this is translated into nested
  2056 case-expressions; missing cases are added and mapped to the predefined
  2057 constant "undefined". In complicated cases printing may no longer show
  2058 the original input but the internal form. Lambda-abstractions allow
  2059 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2060 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2061 variable.
  2062 
  2063 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2064 is an abbreviation for "of_nat :: nat => int". The simplification
  2065 rules for "of_nat" have been changed to work like "int" did
  2066 previously.  Potential INCOMPATIBILITY:
  2067   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2068   - of_nat_diff and of_nat_mult are no longer default simp rules
  2069 
  2070 * Method "algebra" solves polynomial equations over (semi)rings using
  2071 Groebner bases. The (semi)ring structure is defined by locales and the
  2072 tool setup depends on that generic context. Installing the method for
  2073 a specific type involves instantiating the locale and possibly adding
  2074 declarations for computation on the coefficients.  The method is
  2075 already instantiated for natural numbers and for the axiomatic class
  2076 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2077 CALCULEMUS 2007 for the general principles underlying this
  2078 architecture of context-aware proof-tools.
  2079 
  2080 * Method "ferrack" implements quantifier elimination over
  2081 special-purpose dense linear orders using locales (analogous to
  2082 "algebra"). The method is already installed for class
  2083 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2084 rat, etc.
  2085 
  2086 * Former constant "List.op @" now named "List.append".  Use ML
  2087 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2088 circumvent possible incompatibilities when working on ML level.
  2089 
  2090 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2091 
  2092 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2093 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2094 
  2095 * New syntax for Haskell-like list comprehension (input only), eg.
  2096 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2097 
  2098 * The special syntax for function "filter" has changed from [x :
  2099 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2100 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2101 
  2102 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2103 defined on nat only, as an abbreviation for [a..<Suc b]
  2104 INCOMPATIBILITY.
  2105 
  2106 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2107 
  2108 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2109 
  2110 * New lemma collection field_simps (an extension of ring_simps) for
  2111 manipulating (in)equations involving division. Multiplies with all
  2112 denominators that can be proved to be non-zero (in equations) or
  2113 positive/negative (in inequations).
  2114 
  2115 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2116 have been improved and renamed to ring_simps, group_simps and
  2117 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2118 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2119 
  2120 * Theory Library/Commutative_Ring: switched from recdef to function
  2121 package; constants add, mul, pow now curried.  Infix syntax for
  2122 algebraic operations.
  2123 
  2124 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2125 INCOMPATIBILITY.
  2126 
  2127 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2128 INCOMPATIBILITY.
  2129 
  2130 * HOL/records: generalised field-update to take a function on the
  2131 field rather than the new value: r(|A := x|) is translated to A_update
  2132 (K x) r The K-combinator that is internally used is called K_record.
  2133 INCOMPATIBILITY: Usage of the plain update functions has to be
  2134 adapted.
  2135  
  2136 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2137 * x = 0, which are required for a semiring.  Richer structures do not
  2138 inherit from semiring_0 anymore, because this property is a theorem
  2139 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2140 there is more to prove, but this is mostly trivial.
  2141 
  2142 * Class "recpower" is generalized to arbitrary monoids, not just
  2143 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2144 commutativity or semiring properties additionally.
  2145 
  2146 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2147 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2148 better use 'abbreviation'.
  2149 
  2150 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2151 
  2152 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2153 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2154 significant changes for setting up numeral syntax for types:
  2155   - New constants Numeral.pred and Numeral.succ instead
  2156       of former Numeral.bin_pred and Numeral.bin_succ.
  2157   - Use integer operations instead of bin_add, bin_mult and so on.
  2158   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2159   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2160 
  2161 See src/HOL/Integ/IntArith.thy for an example setup.
  2162 
  2163 * Command 'normal_form' computes the normal form of a term that may
  2164 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2165 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2166 heavy-duty computations because the functions are compiled to ML
  2167 first.  Correspondingly, a method "normalization" is provided.  See
  2168 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2169 
  2170 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2171 25 like -->); output depends on the "iff" print_mode, the default is
  2172 "A = B" (with priority 50).
  2173 
  2174 * Relations less (<) and less_eq (<=) are also available on type bool.
  2175 Modified syntax to disallow nesting without explicit parentheses,
  2176 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2177 INCOMPATIBILITY.
  2178 
  2179 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2180 
  2181 * Relation composition operator "op O" now has precedence 75 and binds
  2182 stronger than union and intersection. INCOMPATIBILITY.
  2183 
  2184 * The old set interval syntax "{m..n(}" (and relatives) has been
  2185 removed.  Use "{m..<n}" (and relatives) instead.
  2186 
  2187 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2188 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2189 ``declare [[simproc del: neq]]''.
  2190 
  2191 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2192 True/False.
  2193 
  2194 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2195 
  2196 * Theorem setsum_mult renamed to setsum_right_distrib.
  2197 
  2198 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2199 ``rule'' method.
  2200 
  2201 * Reimplemented methods "sat" and "satx", with several improvements:
  2202 goals no longer need to be stated as "<prems> ==> False", equivalences
  2203 (i.e. "=" on type bool) are handled, variable names of the form
  2204 "lit_<n>" are no longer reserved, significant speedup.
  2205 
  2206 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2207 zChaff is still supported as well.
  2208 
  2209 * 'inductive' and 'datatype': provide projections of mutual rules,
  2210 bundled as foo_bar.inducts;
  2211 
  2212 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2213 Library.
  2214 
  2215 * Library: moved theory Accessible_Part to main HOL.
  2216 
  2217 * Library: added theory Coinductive_List of potentially infinite lists
  2218 as greatest fixed-point.
  2219 
  2220 * Library: added theory AssocList which implements (finite) maps as
  2221 association lists.
  2222 
  2223 * Method "evaluation" solves goals (i.e. a boolean expression)
  2224 efficiently by compiling it to ML.  The goal is "proved" (via an
  2225 oracle) if it evaluates to True.
  2226 
  2227 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2228 also when invoked by the simplifier.  This results in the Simplifier
  2229 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2230 Configuration option fast_arith_split_limit=0 recovers the old
  2231 behavior.
  2232 
  2233 * Support for hex (0x20) and binary (0b1001) numerals.
  2234 
  2235 * New method: reify eqs (t), where eqs are equations for an
  2236 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2237 parameter, computes a term s::'b and a list xs::'a list and proves the
  2238 theorem I xs s = t. This is also known as reification or quoting. The
  2239 resulting theorem is applied to the subgoal to substitute t with I xs
  2240 s.  If t is omitted, the subgoal itself is reified.
  2241 
  2242 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2243 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2244 where f is supposed to be a computable function (in the sense of code
  2245 generattion). The method uses reify to compute s and xs as above then
  2246 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2247 r and finally gets the theorem t = r, which is again applied to the
  2248 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2249 
  2250 * Reflection: Automatic reification now handels binding, an example is
  2251 available in src/HOL/ex/ReflectionEx.thy
  2252 
  2253 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2254 command 'statespace' that is similar to 'record', but introduces an
  2255 abstract specification based on the locale infrastructure instead of
  2256 HOL types.  This leads to extra flexibility in composing state spaces,
  2257 in particular multiple inheritance and renaming of components.
  2258 
  2259 
  2260 *** HOL-Complex ***
  2261 
  2262 * Hyperreal: Functions root and sqrt are now defined on negative real
  2263 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2264 Nonnegativity side conditions have been removed from many lemmas, so
  2265 that more subgoals may now be solved by simplification; potential
  2266 INCOMPATIBILITY.
  2267 
  2268 * Real: new type classes formalize real normed vector spaces and
  2269 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2270 and norm :: 'a => real.
  2271 
  2272 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2273 reals into other types. The overloaded constant Reals :: 'a set is now
  2274 defined as range of_real; potential INCOMPATIBILITY.
  2275 
  2276 * Real: proper support for ML code generation, including 'quickcheck'.
  2277 Reals are implemented as arbitrary precision rationals.
  2278 
  2279 * Hyperreal: Several constants that previously worked only for the
  2280 reals have been generalized, so they now work over arbitrary vector
  2281 spaces. Type annotations may need to be added in some cases; potential
  2282 INCOMPATIBILITY.
  2283 
  2284   Infinitesimal  :: ('a::real_normed_vector) star set
  2285   HFinite        :: ('a::real_normed_vector) star set
  2286   HInfinite      :: ('a::real_normed_vector) star set
  2287   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2288   monad          :: ('a::real_normed_vector) star => 'a star set
  2289   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2290   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2291   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2292   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2293   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2294   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2295   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2296   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2297   sgn            :: 'a::real_normed_vector => 'a
  2298   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2299 
  2300 * Complex: Some complex-specific constants are now abbreviations for
  2301 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2302 hnorm.  Other constants have been entirely removed in favor of the
  2303 polymorphic versions (INCOMPATIBILITY):
  2304 
  2305   approx        <-- capprox
  2306   HFinite       <-- CFinite
  2307   HInfinite     <-- CInfinite
  2308   Infinitesimal <-- CInfinitesimal
  2309   monad         <-- cmonad
  2310   galaxy        <-- cgalaxy
  2311   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2312   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2313   (ns)deriv     <-- (ns)cderiv
  2314 
  2315 
  2316 *** HOL-Algebra ***
  2317 
  2318 * Formalisation of ideals and the quotient construction over rings.
  2319 
  2320 * Order and lattice theory no longer based on records.
  2321 INCOMPATIBILITY.
  2322 
  2323 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2324 greatest_closed.  INCOMPATIBILITY.
  2325 
  2326 * Method algebra is now set up via an attribute.  For examples see
  2327 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2328 of algebraic structures.
  2329 
  2330 * Renamed theory CRing to Ring.
  2331 
  2332 
  2333 *** HOL-Nominal ***
  2334 
  2335 * Substantial, yet incomplete support for nominal datatypes (binding
  2336 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2337 src/HOL/Nominal/Examples.  Prospective users should consult
  2338 http://isabelle.in.tum.de/nominal/
  2339 
  2340 
  2341 *** ML ***
  2342 
  2343 * ML basics: just one true type int, which coincides with IntInf.int
  2344 (even on SML/NJ).
  2345 
  2346 * ML within Isar: antiquotations allow to embed statically-checked
  2347 formal entities in the source, referring to the context available at
  2348 compile-time.  For example:
  2349 
  2350 ML {* @{sort "{zero,one}"} *}
  2351 ML {* @{typ "'a => 'b"} *}
  2352 ML {* @{term "%x. x"} *}
  2353 ML {* @{prop "x == y"} *}
  2354 ML {* @{ctyp "'a => 'b"} *}
  2355 ML {* @{cterm "%x. x"} *}
  2356 ML {* @{cprop "x == y"} *}
  2357 ML {* @{thm asm_rl} *}
  2358 ML {* @{thms asm_rl} *}
  2359 ML {* @{type_name c} *}
  2360 ML {* @{type_syntax c} *}
  2361 ML {* @{const_name c} *}
  2362 ML {* @{const_syntax c} *}
  2363 ML {* @{context} *}
  2364 ML {* @{theory} *}
  2365 ML {* @{theory Pure} *}
  2366 ML {* @{theory_ref} *}
  2367 ML {* @{theory_ref Pure} *}
  2368 ML {* @{simpset} *}
  2369 ML {* @{claset} *}
  2370 ML {* @{clasimpset} *}
  2371 
  2372 The same works for sources being ``used'' within an Isar context.
  2373 
  2374 * ML in Isar: improved error reporting; extra verbosity with
  2375 ML_Context.trace enabled.
  2376 
  2377 * Pure/General/table.ML: the join operations now works via exceptions
  2378 DUP/SAME instead of type option. This is simpler in simple cases, and
  2379 admits slightly more efficient complex applications.
  2380 
  2381 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2382 use Context.generic instead of just theory.
  2383 
  2384 * Pure: datatype Context.generic joins theory/Proof.context and
  2385 provides some facilities for code that works in either kind of
  2386 context, notably GenericDataFun for uniform theory and proof data.
  2387 
  2388 * Pure: simplified internal attribute type, which is now always
  2389 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2390 local (Proof.context) attributes have been discontinued, while
  2391 minimizing code duplication. Thm.rule_attribute and
  2392 Thm.declaration_attribute build canonical attributes; see also structure
  2393 Context for further operations on Context.generic, notably
  2394 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2395 declarations and definitions.
  2396 
  2397 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2398 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2399 init only required for impure data. INCOMPATIBILITY: empty really need
  2400 to be empty (no dependencies on theory content!)
  2401 
  2402 * Pure/kernel: consts certification ignores sort constraints given in
  2403 signature declarations. (This information is not relevant to the
  2404 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2405 potential INCOMPATIBILITY.
  2406 
  2407 * Pure: axiomatic type classes are now purely definitional, with
  2408 explicit proofs of class axioms and super class relations performed
  2409 internally. See Pure/axclass.ML for the main internal interfaces --
  2410 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2411 AxClass.axiomatize_class/classrel/arity supersede
  2412 Sign.add_classes/classrel/arities.
  2413 
  2414 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2415 global/local versions on theory vs. Proof.context have been
  2416 discontinued; Attrib.syntax and Method.syntax have been adapted
  2417 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2418 attributes, methods, etc.
  2419 
  2420 * Pure: several functions of signature "... -> theory -> theory * ..."
  2421 have been reoriented to "... -> theory -> ... * theory" in order to
  2422 allow natural usage in combination with the ||>, ||>>, |-> and
  2423 fold_map combinators.
  2424 
  2425 * Pure: official theorem names (closed derivations) and additional
  2426 comments (tags) are now strictly separate.  Name hints -- which are
  2427 maintained as tags -- may be attached any time without affecting the
  2428 derivation.
  2429 
  2430 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2431 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2432 achieve the old behaviour.
  2433 
  2434 * Pure: the "Goal" constant is now called "prop", supporting a
  2435 slightly more general idea of ``protecting'' meta-level rule
  2436 statements.
  2437 
  2438 * Pure: Logic.(un)varify only works in a global context, which is now
  2439 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2440 Logic.legacy_(un)varify as temporary workaround.
  2441 
  2442 * Pure: structure Name provides scalable operations for generating
  2443 internal variable names, notably Name.variants etc.  This replaces
  2444 some popular functions from term.ML:
  2445 
  2446   Term.variant		->  Name.variant
  2447   Term.variantlist	->  Name.variant_list
  2448   Term.invent_names	->  Name.invent_list
  2449 
  2450 Note that low-level renaming rarely occurs in new code -- operations
  2451 from structure Variable are used instead (see below).
  2452 
  2453 * Pure: structure Variable provides fundamental operations for proper
  2454 treatment of fixed/schematic variables in a context.  For example,
  2455 Variable.import introduces fixes for schematics of given facts and
  2456 Variable.export reverses the effect (up to renaming) -- this replaces
  2457 various freeze_thaw operations.
  2458 
  2459 * Pure: structure Goal provides simple interfaces for
  2460 init/conclude/finish and tactical prove operations (replacing former
  2461 Tactic.prove).  Goal.prove is the canonical way to prove results
  2462 within a given context; Goal.prove_global is a degraded version for
  2463 theory level goals, including a global Drule.standard.  Note that
  2464 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2465 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2466 in a locale context).
  2467 
  2468 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2469 and type checking (Syntax.check_term etc.), with common combinations
  2470 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2471 which are considered legacy and await removal.
  2472 
  2473 * Pure/Syntax: generic interfaces for type unchecking
  2474 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2475 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2476 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2477 available for convenience, but refer to the very same operations using
  2478 a mere theory instead of a full context.
  2479 
  2480 * Isar: simplified treatment of user-level errors, using exception
  2481 ERROR of string uniformly.  Function error now merely raises ERROR,
  2482 without any side effect on output channels.  The Isar toplevel takes
  2483 care of proper display of ERROR exceptions.  ML code may use plain
  2484 handle/can/try; cat_error may be used to concatenate errors like this:
  2485 
  2486   ... handle ERROR msg => cat_error msg "..."
  2487 
  2488 Toplevel ML code (run directly or through the Isar toplevel) may be
  2489 embedded into the Isar toplevel with exception display/debug like
  2490 this:
  2491 
  2492   Isar.toplevel (fn () => ...)
  2493 
  2494 INCOMPATIBILITY, removed special transform_error facilities, removed
  2495 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2496 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2497 -- use plain ERROR instead.
  2498 
  2499 * Isar: theory setup now has type (theory -> theory), instead of a
  2500 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2501 
  2502 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2503 ProofContext.debug/verbose flags.
  2504 
  2505 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2506 theory before entering a proof state.  Transactions now always see a
  2507 quasi-functional intermediate checkpoint, both in interactive and
  2508 batch mode.
  2509 
  2510 * Isar: simplified interfaces for outer syntax.  Renamed
  2511 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2512 OuterSyntax.add_parsers -- this functionality is now included in
  2513 OuterSyntax.command etc.  INCOMPATIBILITY.
  2514 
  2515 * Simplifier: the simpset of a running simplification process now
  2516 contains a proof context (cf. Simplifier.the_context), which is the
  2517 very context that the initial simpset has been retrieved from (by
  2518 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2519 (solver, looper etc.) may depend on arbitrary proof data.
  2520 
  2521 * Simplifier.inherit_context inherits the proof context (plus the
  2522 local bounds) of the current simplification process; any simproc
  2523 etc. that calls the Simplifier recursively should do this!  Removed
  2524 former Simplifier.inherit_bounds, which is already included here --
  2525 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2526 specify an explicit context using Simplifier.context/theory_context.
  2527 
  2528 * Simplifier/Classical Reasoner: more abstract interfaces
  2529 change_simpset/claset for modifying the simpset/claset reference of a
  2530 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2531 INCOMPATIBILITY.
  2532 
  2533 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2534 "Trueprop" etc.
  2535 
  2536 
  2537 *** System ***
  2538 
  2539 * settings: the default heap location within ISABELLE_HOME_USER now
  2540 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2541 Isabelle installations.
  2542 
  2543 * isabelle-process: option -S (secure mode) disables some critical
  2544 operations, notably runtime compilation and evaluation of ML source
  2545 code.
  2546 
  2547 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2548 
  2549 * Support for parallel execution, using native multicore support of
  2550 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2551 independent theories, according to the given theory header
  2552 specifications. The maximum number of worker threads is specified via
  2553 usedir option -M or the "max-threads" setting in Proof General. A
  2554 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2555 to 6 on a 8-core machine.  User-code needs to observe certain
  2556 guidelines for thread-safe programming, see appendix A in the Isar
  2557 Implementation manual.
  2558 
  2559 
  2560 
  2561 New in Isabelle2005 (October 2005)
  2562 ----------------------------------
  2563 
  2564 *** General ***
  2565 
  2566 * Theory headers: the new header syntax for Isar theories is
  2567 
  2568   theory <name>
  2569   imports <theory1> ... <theoryN>
  2570   uses <file1> ... <fileM>
  2571   begin
  2572 
  2573 where the 'uses' part is optional.  The previous syntax
  2574 
  2575   theory <name> = <theory1> + ... + <theoryN>:
  2576 
  2577 will disappear in the next release.  Use isatool fixheaders to convert
  2578 existing theory files.  Note that there is no change in ancient
  2579 non-Isar theories now, but these will disappear soon.
  2580 
  2581 * Theory loader: parent theories can now also be referred to via
  2582 relative and absolute paths.
  2583 
  2584 * Command 'find_theorems' searches for a list of criteria instead of a
  2585 list of constants. Known criteria are: intro, elim, dest, name:string,
  2586 simp:term, and any term. Criteria can be preceded by '-' to select
  2587 theorems that do not match. Intro, elim, dest select theorems that
  2588 match the current goal, name:s selects theorems whose fully qualified
  2589 name contain s, and simp:term selects all simplification rules whose
  2590 lhs match term.  Any other term is interpreted as pattern and selects
  2591 all theorems matching the pattern. Available in ProofGeneral under
  2592 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2593 
  2594   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2595 
  2596 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2597 matching the current goal as introduction rule and not having "HOL."
  2598 in their name (i.e. not being defined in theory HOL).
  2599 
  2600 * Command 'thms_containing' has been discontinued in favour of
  2601 'find_theorems'; INCOMPATIBILITY.
  2602 
  2603 * Communication with Proof General is now 8bit clean, which means that
  2604 Unicode text in UTF-8 encoding may be used within theory texts (both
  2605 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2606 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2607 
  2608   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2609   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2610 
  2611 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2612 Classical Reasoner.  Typical big applications run around 2 times
  2613 faster.
  2614 
  2615 
  2616 *** Document preparation ***
  2617 
  2618 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2619 of raw sources.  Only those symbols that do not require additional
  2620 LaTeX packages (depending on comments in isabellesym.sty) are
  2621 displayed properly, everything else is left verbatim.  isatool display
  2622 and isatool print are used as front ends (these are subject to the
  2623 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2624 
  2625 * Command tags control specific markup of certain regions of text,
  2626 notably folding and hiding.  Predefined tags include "theory" (for
  2627 theory begin and end), "proof" for proof commands, and "ML" for
  2628 commands involving ML code; the additional tags "visible" and
  2629 "invisible" are unused by default.  Users may give explicit tag
  2630 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2631 interpretation of tags is determined by the LaTeX job during document
  2632 preparation: see option -V of isatool usedir, or options -n and -t of
  2633 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2634 \isadroptag.
  2635 
  2636 Several document versions may be produced at the same time via isatool
  2637 usedir (the generated index.html will link all of them).  Typical
  2638 specifications include ''-V document=theory,proof,ML'' to present
  2639 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2640 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2641 these parts without any formal replacement text.  The Isabelle site
  2642 default settings produce ''document'' and ''outline'' versions as
  2643 specified above.
  2644 
  2645 * Several new antiquotations:
  2646 
  2647   @{term_type term} prints a term with its type annotated;
  2648 
  2649   @{typeof term} prints the type of a term;
  2650 
  2651   @{const const} is the same as @{term const}, but checks that the
  2652   argument is a known logical constant;
  2653 
  2654   @{term_style style term} and @{thm_style style thm} print a term or
  2655   theorem applying a "style" to it
  2656 
  2657   @{ML text}
  2658 
  2659 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2660 definitions, equations, inequations etc., 'concl' printing only the
  2661 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2662 to print the specified premise.  TermStyle.add_style provides an ML
  2663 interface for introducing further styles.  See also the "LaTeX Sugar"
  2664 document practical applications.  The ML antiquotation prints
  2665 type-checked ML expressions verbatim.
  2666 
  2667 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2668 and 'text' support optional locale specification '(in loc)', which
  2669 specifies the default context for interpreting antiquotations.  For
  2670 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2671 
  2672 * Option 'locale=NAME' of antiquotations specifies an alternative
  2673 context interpreting the subsequent argument.  For example: @{thm
  2674 [locale=lattice] inf_assoc}.
  2675 
  2676 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2677 a proof context.
  2678 
  2679 * Proper output of antiquotations for theory commands involving a
  2680 proof context (such as 'locale' or 'theorem (in loc) ...').
  2681 
  2682 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2683 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2684 
  2685 * isatool usedir: new option -C (default true) controls whether option
  2686 -D should include a copy of the original document directory; -C false
  2687 prevents unwanted effects such as copying of administrative CVS data.
  2688 
  2689 
  2690 *** Pure ***
  2691 
  2692 * Considerably improved version of 'constdefs' command.  Now performs
  2693 automatic type-inference of declared constants; additional support for
  2694 local structure declarations (cf. locales and HOL records), see also
  2695 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2696 sequential dependencies of definitions within a single 'constdefs'
  2697 section; moreover, the declared name needs to be an identifier.  If
  2698 all fails, consider to fall back on 'consts' and 'defs' separately.
  2699 
  2700 * Improved indexed syntax and implicit structures.  First of all,
  2701 indexed syntax provides a notational device for subscripted
  2702 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2703 expressions.  Secondly, in a local context with structure
  2704 declarations, number indexes \<^sub>n or the empty index (default
  2705 number 1) refer to a certain fixed variable implicitly; option
  2706 show_structs controls printing of implicit structures.  Typical
  2707 applications of these concepts involve record types and locales.
  2708 
  2709 * New command 'no_syntax' removes grammar declarations (and
  2710 translations) resulting from the given syntax specification, which is
  2711 interpreted in the same manner as for the 'syntax' command.
  2712 
  2713 * 'Advanced' translation functions (parse_translation etc.) may depend
  2714 on the signature of the theory context being presently used for
  2715 parsing/printing, see also isar-ref manual.
  2716 
  2717 * Improved 'oracle' command provides a type-safe interface to turn an
  2718 ML expression of type theory -> T -> term into a primitive rule of
  2719 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2720 is already included here); see also FOL/ex/IffExample.thy;
  2721 INCOMPATIBILITY.
  2722 
  2723 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2724 before); "cI" is no longer bound, use "c.intro" instead.
  2725 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2726 axclasses vs. locales.
  2727 
  2728 * Improved internal renaming of symbolic identifiers -- attach primes
  2729 instead of base 26 numbers.
  2730 
  2731 * New flag show_question_marks controls printing of leading question
  2732 marks in schematic variable names.
  2733 
  2734 * In schematic variable names, *any* symbol following \<^isub> or
  2735 \<^isup> is now treated as part of the base name.  For example, the
  2736 following works without printing of awkward ".0" indexes:
  2737 
  2738   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2739     by simp
  2740 
  2741 * Inner syntax includes (*(*nested*) comments*).
  2742 
  2743 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2744 annotations as "(00...)".
  2745 
  2746 * Clear separation of logical types and nonterminals, where the latter
  2747 may only occur in 'syntax' specifications or type abbreviations.
  2748 Before that distinction was only partially implemented via type class
  2749 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2750 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2751 exotic syntax specifications may require further adaption
  2752 (e.g. Cube/Cube.thy).
  2753 
  2754 * Removed obsolete type class "logic", use the top sort {} instead.
  2755 Note that non-logical types should be declared as 'nonterminals'
  2756 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2757 specifications.
  2758 
  2759 * Attributes 'induct' and 'cases': type or set names may now be
  2760 locally fixed variables as well.
  2761 
  2762 * Simplifier: can now control the depth to which conditional rewriting
  2763 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2764 Limit.
  2765 
  2766 * Simplifier: simplification procedures may now take the current
  2767 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2768 interface), which is very useful for calling the Simplifier
  2769 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2770 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2771 low-level mk_simproc no longer applies Logic.varify internally, to
  2772 allow for use in a context of fixed variables.
  2773 
  2774 * thin_tac now works even if the assumption being deleted contains !!
  2775 or ==>.  More generally, erule now works even if the major premise of
  2776 the elimination rule contains !! or ==>.
  2777 
  2778 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2779 
  2780 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2781 from Pure, which contains all common declarations already.  Both
  2782 theories are defined via plain Isabelle/Isar .thy files.
  2783 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2784 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2785 use isatool fixcpure to adapt your theory and ML sources.
  2786 
  2787 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2788 selections of theorems in named facts via index ranges.
  2789 
  2790 * 'print_theorems': in theory mode, really print the difference
  2791 wrt. the last state (works for interactive theory development only),
  2792 in proof mode print all local facts (cf. 'print_facts');
  2793 
  2794 * 'hide': option '(open)' hides only base names.
  2795 
  2796 * More efficient treatment of intermediate checkpoints in interactive
  2797 theory development.
  2798 
  2799 * Code generator is now invoked via code_module (incremental code
  2800 generation) and code_library (modular code generation, ML structures
  2801 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2802 must be quoted when used as identifiers.
  2803 
  2804 * New 'value' command for reading, evaluating and printing terms using
  2805 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2806 quoted when used as identifier.
  2807 
  2808 
  2809 *** Locales ***
  2810 
  2811 * New commands for the interpretation of locale expressions in
  2812 theories (1), locales (2) and proof contexts (3).  These generate
  2813 proof obligations from the expression specification.  After the
  2814 obligations have been discharged, theorems of the expression are added
  2815 to the theory, target locale or proof context.  The synopsis of the
  2816 commands is a follows:
  2817 
  2818   (1) interpretation expr inst
  2819   (2) interpretation target < expr
  2820   (3) interpret expr inst
  2821 
  2822 Interpretation in theories and proof contexts require a parameter
  2823 instantiation of terms from the current context.  This is applied to
  2824 specifications and theorems of the interpreted expression.
  2825 Interpretation in locales only permits parameter renaming through the
  2826 locale expression.  Interpretation is smart in that interpretations
  2827 that are active already do not occur in proof obligations, neither are
  2828 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2829 inspect active interpretations of a particular locale.  For details,
  2830 see the Isar Reference manual.  Examples can be found in
  2831 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2832 
  2833 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2834 'interpret' instead.
  2835 
  2836 * New context element 'constrains' for adding type constraints to
  2837 parameters.
  2838 
  2839 * Context expressions: renaming of parameters with syntax
  2840 redeclaration.
  2841 
  2842 * Locale declaration: 'includes' disallowed.
  2843 
  2844 * Proper static binding of attribute syntax -- i.e. types / terms /
  2845 facts mentioned as arguments are always those of the locale definition
  2846 context, independently of the context of later invocations.  Moreover,
  2847 locale operations (renaming and type / term instantiation) are applied
  2848 to attribute arguments as expected.
  2849 
  2850 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2851 actual attributes; rare situations may require Attrib.attribute to
  2852 embed those attributes into Attrib.src that lack concrete syntax.
  2853 Attribute implementations need to cooperate properly with the static
  2854 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2855 Attrib.XXX_thm etc. already do the right thing without further
  2856 intervention.  Only unusual applications -- such as "where" or "of"
  2857 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2858 on the context and the facts involved -- may have to assign parsed
  2859 values to argument tokens explicitly.
  2860 
  2861 * Changed parameter management in theorem generation for long goal
  2862 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2863 theorem statement in rare situations.
  2864 
  2865 * Locale inspection command 'print_locale' omits notes elements.  Use
  2866 'print_locale!' to have them included in the output.
  2867 
  2868 
  2869 *** Provers ***
  2870 
  2871 * Provers/hypsubst.ML: improved version of the subst method, for
  2872 single-step rewriting: it now works in bound variable contexts. New is
  2873 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2874 rewrite a different subterm than the original subst method, which is
  2875 still available as 'simplesubst'.
  2876 
  2877 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2878 and quasi orders.
  2879 
  2880 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2881 reflexive-transitive closure of relations.
  2882 
  2883 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2884 limit (previously hard-coded with a value of 20) user-definable.
  2885 
  2886 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2887 is peformed already.  Object-logics merely need to finish their
  2888 initial simpset configuration as before.  INCOMPATIBILITY.
  2889 
  2890 
  2891 *** HOL ***
  2892 
  2893 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2894 
  2895   syntax (epsilon)
  2896     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2897 
  2898 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2899 and x-symbol; use option '-m epsilon' to get it actually printed.
  2900 Moreover, the mathematically important symbolic identifier \<epsilon>
  2901 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2902 
  2903 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2904 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2905 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2906 support corresponding Isar calculations.
  2907 
  2908 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2909 instead of ":".
  2910 
  2911 * theory SetInterval: changed the syntax for open intervals:
  2912 
  2913   Old       New
  2914   {..n(}    {..<n}
  2915   {)n..}    {n<..}
  2916   {m..n(}   {m..<n}
  2917   {)m..n}   {m<..n}
  2918   {)m..n(}  {m<..<n}
  2919 
  2920 The old syntax is still supported but will disappear in the next
  2921 release.  For conversion use the following Emacs search and replace
  2922 patterns (these are not perfect but work quite well):
  2923 
  2924   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2925   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2926 
  2927 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2928 equalities in commutative rings; method 'algebra' provides a generic
  2929 interface.
  2930 
  2931 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2932 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2933 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2934 be a tuple pattern.
  2935 
  2936 Some new syntax forms are available:
  2937 
  2938   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2939   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2940   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2941   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2942 
  2943 The latter form "\<Sum>x < k. e" used to be based on a separate
  2944 function "Summation", which has been discontinued.
  2945 
  2946 * theory Finite_Set: in structured induction proofs, the insert case
  2947 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2948 (insert F x)'.
  2949 
  2950 * The 'refute' command has been extended to support a much larger
  2951 fragment of HOL, including axiomatic type classes, constdefs and
  2952 typedefs, inductive datatypes and recursion.
  2953 
  2954 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2955 Requires zChaff with proof generation to be installed.  See
  2956 HOL/ex/SAT_Examples.thy for examples.
  2957 
  2958 * Datatype induction via method 'induct' now preserves the name of the
  2959 induction variable. For example, when proving P(xs::'a list) by
  2960 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2961 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2962 in unstructured proof scripts.
  2963 
  2964 * Reworked implementation of records.  Improved scalability for
  2965 records with many fields, avoiding performance problems for type
  2966 inference. Records are no longer composed of nested field types, but
  2967 of nested extension types. Therefore the record type only grows linear
  2968 in the number of extensions and not in the number of fields.  The
  2969 top-level (users) view on records is preserved.  Potential
  2970 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2971 old record representation. The type generated for a record is called
  2972 <record_name>_ext_type.
  2973 
  2974 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2975 proofs triggered by a record definition or a simproc (if
  2976 quick_and_dirty is enabled).  Definitions of large records can take
  2977 quite long.
  2978 
  2979 New simproc record_upd_simproc for simplification of multiple record
  2980 updates enabled by default.  Moreover, trivial updates are also
  2981 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2982 occasionally, since simplification is more powerful by default.
  2983 
  2984 * typedef: proper support for polymorphic sets, which contain extra
  2985 type-variables in the term.
  2986 
  2987 * Simplifier: automatically reasons about transitivity chains
  2988 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2989 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2990 old proofs break occasionally as simplification may now solve more
  2991 goals than previously.
  2992 
  2993 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2994 present.  Works for all partial orders (class "order"), in particular
  2995 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2996 just like y <= x.
  2997 
  2998 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2999 bound variable or a constant then the let is unfolded.  Otherwise
  3000 first a is simplified to b, and then f b is simplified to g. If
  3001 possible we abstract b from g arriving at "let x = b in h x",
  3002 otherwise we unfold the let and arrive at g.  The simproc can be
  3003 enabled/disabled by the reference use_let_simproc.  Potential
  3004 INCOMPATIBILITY since simplification is more powerful by default.
  3005 
  3006 * Classical reasoning: the meson method now accepts theorems as arguments.
  3007 
  3008 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3009 jobs to provide advice on the provability of subgoals.
  3010 
  3011 * Theory OrderedGroup and Ring_and_Field: various additions and
  3012 improvements to faciliate calculations involving equalities and
  3013 inequalities.
  3014 
  3015 The following theorems have been eliminated or modified
  3016 (INCOMPATIBILITY):
  3017 
  3018   abs_eq             now named abs_of_nonneg
  3019   abs_of_ge_0        now named abs_of_nonneg
  3020   abs_minus_eq       now named abs_of_nonpos
  3021   imp_abs_id         now named abs_of_nonneg
  3022   imp_abs_neg_id     now named abs_of_nonpos
  3023   mult_pos           now named mult_pos_pos
  3024   mult_pos_le        now named mult_nonneg_nonneg
  3025   mult_pos_neg_le    now named mult_nonneg_nonpos
  3026   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3027   mult_neg           now named mult_neg_neg
  3028   mult_neg_le        now named mult_nonpos_nonpos
  3029 
  3030 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3031      
  3032      zero_le_square
  3033      not_square_less_zero 
  3034 
  3035   The following lemmas have been deleted from Real/RealPow:
  3036   
  3037      realpow_zero_zero
  3038      realpow_two
  3039      realpow_less
  3040      zero_le_power
  3041      realpow_two_le
  3042      abs_realpow_two
  3043      realpow_two_abs     
  3044 
  3045 * Theory Parity: added rules for simplifying exponents.
  3046 
  3047 * Theory List:
  3048 
  3049 The following theorems have been eliminated or modified
  3050 (INCOMPATIBILITY):
  3051 
  3052   list_all_Nil       now named list_all.simps(1)
  3053   list_all_Cons      now named list_all.simps(2)
  3054   list_all_conv      now named list_all_iff
  3055   set_mem_eq         now named mem_iff
  3056 
  3057 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3058 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3059 
  3060 
  3061 *** HOL-Complex ***
  3062 
  3063 * Theory RealDef: better support for embedding natural numbers and
  3064 integers in the reals.
  3065 
  3066 The following theorems have been eliminated or modified
  3067 (INCOMPATIBILITY):
  3068 
  3069   exp_ge_add_one_self  now requires no hypotheses
  3070   real_of_int_add      reversed direction of equality (use [symmetric])
  3071   real_of_int_minus    reversed direction of equality (use [symmetric])
  3072   real_of_int_diff     reversed direction of equality (use [symmetric])
  3073   real_of_int_mult     reversed direction of equality (use [symmetric])
  3074 
  3075 * Theory RComplete: expanded support for floor and ceiling functions.
  3076 
  3077 * Theory Ln is new, with properties of the natural logarithm
  3078 
  3079 * Hyperreal: There is a new type constructor "star" for making
  3080 nonstandard types.  The old type names are now type synonyms:
  3081 
  3082   hypreal = real star
  3083   hypnat = nat star
  3084   hcomplex = complex star
  3085 
  3086 * Hyperreal: Many groups of similarly-defined constants have been
  3087 replaced by polymorphic versions (INCOMPATIBILITY):
  3088 
  3089   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3090 
  3091   starset      <-- starsetNat, starsetC
  3092   *s*          <-- *sNat*, *sc*
  3093   starset_n    <-- starsetNat_n, starsetC_n
  3094   *sn*         <-- *sNatn*, *scn*
  3095   InternalSets <-- InternalNatSets, InternalCSets
  3096 
  3097   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3098   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3099   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3100   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3101   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3102 
  3103 * Hyperreal: Many type-specific theorems have been removed in favor of
  3104 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3105 
  3106   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3107   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3108   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3109   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3110   right_minus <-- hypreal_add_minus
  3111   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3112   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3113   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3114   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3115   mult_1_right <-- hcomplex_mult_one_right
  3116   mult_zero_left <-- hcomplex_mult_zero_left
  3117   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3118   right_distrib <-- hypnat_add_mult_distrib2
  3119   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3120   right_inverse <-- hypreal_mult_inverse
  3121   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3122   order_refl <-- {hypreal,hypnat}_le_refl
  3123   order_trans <-- {hypreal,hypnat}_le_trans
  3124   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3125   order_less_le <-- {hypreal,hypnat}_less_le
  3126   linorder_linear <-- {hypreal,hypnat}_le_linear
  3127   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3128   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3129   add_nonneg_nonneg <-- hypreal_le_add_order
  3130 
  3131 * Hyperreal: Separate theorems having to do with type-specific
  3132 versions of constants have been merged into theorems that apply to the
  3133 new polymorphic constants (INCOMPATIBILITY):
  3134 
  3135   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3136   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3137   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3138   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3139   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3140   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3141   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3142   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3143   STAR_diff <-- {STAR,STARC}_diff
  3144   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3145     STARC_hcomplex_of_complex}_image_subset
  3146   starset_n_Un <-- starset{Nat,C}_n_Un
  3147   starset_n_Int <-- starset{Nat,C}_n_Int
  3148   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3149   starset_n_diff <-- starset{Nat,C}_n_diff
  3150   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3151   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3152   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3153   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3154   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3155   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3156   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3157   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3158   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3159   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3160   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3161   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3162   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3163   starfun_diff <-- starfun{C,RC,CR}_diff
  3164   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3165   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3166   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3167   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3168   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3169   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3170   starfun_Id <-- starfunC_Id
  3171   starfun_approx <-- starfun{Nat,CR}_approx
  3172   starfun_capprox <-- starfun{C,RC}_capprox
  3173   starfun_abs <-- starfunNat_rabs
  3174   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3175   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3176   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3177   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3178   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3179   starfun_add_approx <-- starfunCR_add_approx
  3180   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3181   starfun_divide <-- starfun{C,CR,RC}_divide
  3182   starfun_n <-- starfun{Nat,C}_n
  3183   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3184   starfun_n_add <-- starfun{Nat,C}_n_add
  3185   starfun_n_add_minus <-- starfunNat_n_add_minus
  3186   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3187   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3188   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3189 
  3190   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3191   star_n_minus <-- {hypreal,hcomplex}_minus
  3192   star_n_diff <-- {hypreal,hcomplex}_diff
  3193   star_n_mult <-- {hypreal,hcomplex}_mult
  3194   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3195   star_n_le <-- {hypreal,hypnat}_le
  3196   star_n_less <-- {hypreal,hypnat}_less
  3197   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3198   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3199   star_n_abs <-- hypreal_hrabs
  3200   star_n_divide <-- hcomplex_divide
  3201 
  3202   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3203   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3204   star_of_diff <-- hypreal_of_real_diff
  3205   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3206   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3207   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3208   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3209   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3210   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3211   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3212   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3213   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3214   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3215   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3216   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3217   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3218   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3219   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3220   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3221   star_of_power <-- hypreal_of_real_power
  3222   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3223 
  3224 * Hyperreal: new method "transfer" that implements the transfer
  3225 principle of nonstandard analysis. With a subgoal that mentions
  3226 nonstandard types like "'a star", the command "apply transfer"
  3227 replaces it with an equivalent one that mentions only standard types.
  3228 To be successful, all free variables must have standard types; non-
  3229 standard variables must have explicit universal quantifiers.
  3230 
  3231 * Hyperreal: A theory of Taylor series.
  3232 
  3233 
  3234 *** HOLCF ***
  3235 
  3236 * Discontinued special version of 'constdefs' (which used to support
  3237 continuous functions) in favor of the general Pure one with full
  3238 type-inference.
  3239 
  3240 * New simplification procedure for solving continuity conditions; it
  3241 is much faster on terms with many nested lambda abstractions (cubic
  3242 instead of exponential time).
  3243 
  3244 * New syntax for domain package: selector names are now optional.
  3245 Parentheses should be omitted unless argument is lazy, for example:
  3246 
  3247   domain 'a stream = cons "'a" (lazy "'a stream")
  3248 
  3249 * New command 'fixrec' for defining recursive functions with pattern
  3250 matching; defining multiple functions with mutual recursion is also
  3251 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3252 sinr, or any data constructor defined by the domain package. The given
  3253 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3254 syntax and examples.
  3255 
  3256 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3257 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3258 but the proof obligation additionally includes an admissibility
  3259 requirement. The packages generate instances of class cpo or pcpo,
  3260 with continuity and strictness theorems for Rep and Abs.
  3261 
  3262 * HOLCF: Many theorems have been renamed according to a more standard naming
  3263 scheme (INCOMPATIBILITY):
  3264 
  3265   foo_inject:  "foo$x = foo$y ==> x = y"
  3266   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3267   foo_less:    "(foo$x << foo$y) = (x << y)"
  3268   foo_strict:  "foo$UU = UU"
  3269   foo_defined: "... ==> foo$x ~= UU"
  3270   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3271 
  3272 
  3273 *** ZF ***
  3274 
  3275 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3276 including the First Isomorphism Theorem (on quotienting by the kernel
  3277 of a homomorphism).
  3278 
  3279 * ZF/Simplifier: install second copy of type solver that actually
  3280 makes use of TC rules declared to Isar proof contexts (or locales);
  3281 the old version is still required for ML proof scripts.
  3282 
  3283 
  3284 *** Cube ***
  3285 
  3286 * Converted to Isar theory format; use locales instead of axiomatic
  3287 theories.
  3288 
  3289 
  3290 *** ML ***
  3291 
  3292 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3293 for ||>, ||>>, |>>,
  3294 
  3295 * Pure/library.ML no longer defines its own option datatype, but uses
  3296 that of the SML basis, which has constructors NONE and SOME instead of
  3297 None and Some, as well as exception Option.Option instead of OPTION.
  3298 The functions the, if_none, is_some, is_none have been adapted
  3299 accordingly, while Option.map replaces apsome.
  3300 
  3301 * Pure/library.ML: the exception LIST has been given up in favour of
  3302 the standard exceptions Empty and Subscript, as well as
  3303 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3304 superceded by the standard hd and tl functions etc.
  3305 
  3306 A number of basic list functions are no longer exported to the ML
  3307 toplevel, as they are variants of predefined functions.  The following
  3308 suggests how one can translate existing code:
  3309 
  3310     rev_append xs ys = List.revAppend (xs, ys)
  3311     nth_elem (i, xs) = List.nth (xs, i)
  3312     last_elem xs = List.last xs
  3313     flat xss = List.concat xss
  3314     seq fs = List.app fs
  3315     partition P xs = List.partition P xs
  3316     mapfilter f xs = List.mapPartial f xs
  3317 
  3318 * Pure/library.ML: several combinators for linear functional
  3319 transformations, notably reverse application and composition:
  3320 
  3321   x |> f                f #> g
  3322   (x, y) |-> f          f #-> g
  3323 
  3324 * Pure/library.ML: introduced/changed precedence of infix operators:
  3325 
  3326   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3327   infix 2 ?;
  3328   infix 3 o oo ooo oooo;
  3329   infix 4 ~~ upto downto;
  3330 
  3331 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3332 infix operators.
  3333 
  3334 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3335 fold_map support linear functional transformations and nesting.  For
  3336 example:
  3337 
  3338   fold f [x1, ..., xN] y =
  3339     y |> f x1 |> ... |> f xN
  3340 
  3341   (fold o fold) f [xs1, ..., xsN] y =
  3342     y |> fold f xs1 |> ... |> fold f xsN
  3343 
  3344   fold f [x1, ..., xN] =
  3345     f x1 #> ... #> f xN
  3346 
  3347   (fold o fold) f [xs1, ..., xsN] =
  3348     fold f xs1 #> ... #> fold f xsN
  3349 
  3350 * Pure/library.ML: the following selectors on type 'a option are
  3351 available:
  3352 
  3353   the:               'a option -> 'a  (*partial*)
  3354   these:             'a option -> 'a  where 'a = 'b list
  3355   the_default: 'a -> 'a option -> 'a
  3356   the_list:          'a option -> 'a list
  3357 
  3358 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3359 basic operations for association lists, following natural argument
  3360 order; moreover the explicit equality predicate passed here avoids
  3361 potentially expensive polymorphic runtime equality checks.
  3362 The old functions may be expressed as follows:
  3363 
  3364   assoc = uncurry (AList.lookup (op =))
  3365   assocs = these oo AList.lookup (op =)
  3366   overwrite = uncurry (AList.update (op =)) o swap
  3367 
  3368 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3369 
  3370   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3371   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3372 
  3373 replacing make_keylist and keyfilter (occassionally used)
  3374 Naive rewrites:
  3375 
  3376   make_keylist = AList.make
  3377   keyfilter = AList.find (op =)
  3378 
  3379 * eq_fst and eq_snd now take explicit equality parameter, thus
  3380   avoiding eqtypes. Naive rewrites:
  3381 
  3382     eq_fst = eq_fst (op =)
  3383     eq_snd = eq_snd (op =)
  3384 
  3385 * Removed deprecated apl and apr (rarely used).
  3386   Naive rewrites:
  3387 
  3388     apl (n, op) =>>= curry op n
  3389     apr (op, m) =>>= fn n => op (n, m)
  3390 
  3391 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3392 provides a reasonably efficient light-weight implementation of sets as
  3393 lists.
  3394 
  3395 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3396 few new operations; existing lookup and update are now curried to
  3397 follow natural argument order (for use with fold etc.);
  3398 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3399 
  3400 * Pure/General: output via the Isabelle channels of
  3401 writeln/warning/error etc. is now passed through Output.output, with a
  3402 hook for arbitrary transformations depending on the print_mode
  3403 (cf. Output.add_mode -- the first active mode that provides a output
  3404 function wins).  Already formatted output may be embedded into further
  3405 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3406 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3407 accommodate easy composition of diagnostic messages etc.  Programmers
  3408 rarely need to care about Output.output or Output.raw at all, with
  3409 some notable exceptions: Output.output is required when bypassing the
  3410 standard channels (writeln etc.), or in token translations to produce
  3411 properly formatted results; Output.raw is required when capturing
  3412 already output material that will eventually be presented to the user
  3413 a second time.  For the default print mode, both Output.output and
  3414 Output.raw have no effect.
  3415 
  3416 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3417 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3418 cumulative results are displayed at the end of a batch session.
  3419 
  3420 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3421 replaced by File.platform_path and File.shell_path (with appropriate
  3422 hooks).  This provides a clean interface for unusual systems where the
  3423 internal and external process view of file names are different.
  3424 
  3425 * Pure: more efficient orders for basic syntactic entities: added
  3426 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3427 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3428 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3429 orders now -- potential INCOMPATIBILITY for code that depends on a
  3430 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3431 Library.sort_strings on result).
  3432 
  3433 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3434 fold_types traverse types/terms from left to right, observing natural
  3435 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3436 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3437 
  3438 * Pure: name spaces have been refined, with significant changes of the
  3439 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3440 to extern(_table).  The plain name entry path is superceded by a
  3441 general 'naming' context, which also includes the 'policy' to produce
  3442 a fully qualified name and external accesses of a fully qualified
  3443 name; NameSpace.extend is superceded by context dependent
  3444 Sign.declare_name.  Several theory and proof context operations modify
  3445 the naming context.  Especially note Theory.restore_naming and
  3446 ProofContext.restore_naming to get back to a sane state; note that
  3447 Theory.add_path is no longer sufficient to recover from
  3448 Theory.absolute_path in particular.
  3449 
  3450 * Pure: new flags short_names (default false) and unique_names
  3451 (default true) for controlling output of qualified names.  If
  3452 short_names is set, names are printed unqualified.  If unique_names is
  3453 reset, the name prefix is reduced to the minimum required to achieve
  3454 the original result when interning again, even if there is an overlap
  3455 with earlier declarations.
  3456 
  3457 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3458 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3459 (useful for printing error messages).  INCOMPATIBILITY.
  3460 
  3461 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3462 Theory.theory are now identified, referring to the universal
  3463 Context.theory (see Pure/context.ML).  Actual signature and theory
  3464 content is managed as theory data.  The old code and interfaces were
  3465 spread over many files and structures; the new arrangement introduces
  3466 considerable INCOMPATIBILITY to gain more clarity:
  3467 
  3468   Context -- theory management operations (name, identity, inclusion,
  3469     parents, ancestors, merge, etc.), plus generic theory data;
  3470 
  3471   Sign -- logical signature and syntax operations (declaring consts,
  3472     types, etc.), plus certify/read for common entities;
  3473 
  3474   Theory -- logical theory operations (stating axioms, definitions,
  3475     oracles), plus a copy of logical signature operations (consts,
  3476     types, etc.); also a few basic management operations (Theory.copy,
  3477     Theory.merge, etc.)
  3478 
  3479 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3480 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3481 for convenience -- they merely return the theory.
  3482 
  3483 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3484 
  3485 * Pure: the Isar proof context type is already defined early in Pure
  3486 as Context.proof (note that ProofContext.context and Proof.context are
  3487 aliases, where the latter is the preferred name).  This enables other
  3488 Isabelle components to refer to that type even before Isar is present.
  3489 
  3490 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3491 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3492 any of these kinds.  For example, Sign.intern typeK is now
  3493 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3494 Theory.hide_types.  Also note that former
  3495 Theory.hide_classes/types/consts are now
  3496 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3497 internalize their arguments!  INCOMPATIBILITY.
  3498 
  3499 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3500 datatype thmref (with constructors Name and NameSelection) instead of
  3501 plain string -- INCOMPATIBILITY;
  3502 
  3503 * Pure: cases produced by proof methods specify options, where NONE
  3504 means to remove case bindings -- INCOMPATIBILITY in
  3505 (RAW_)METHOD_CASES.
  3506 
  3507 * Pure: the following operations retrieve axioms or theorems from a
  3508 theory node or theory hierarchy, respectively:
  3509 
  3510   Theory.axioms_of: theory -> (string * term) list
  3511   Theory.all_axioms_of: theory -> (string * term) list
  3512   PureThy.thms_of: theory -> (string * thm) list
  3513   PureThy.all_thms_of: theory -> (string * thm) list
  3514 
  3515 * Pure: print_tac now outputs the goal through the trace channel.
  3516 
  3517 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3518 Reference Toplevel.debug (default false) controls detailed printing
  3519 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3520 controls execution profiling -- set to 1 for time and 2 for space
  3521 (both increase the runtime).
  3522 
  3523 * Isar session: The initial use of ROOT.ML is now always timed,
  3524 i.e. the log will show the actual process times, in contrast to the
  3525 elapsed wall-clock time that the outer shell wrapper produces.
  3526 
  3527 * Simplifier: improved handling of bound variables (nameless
  3528 representation, avoid allocating new strings).  Simprocs that invoke
  3529 the Simplifier recursively should use Simplifier.inherit_bounds to
  3530 avoid local name clashes.  Failure to do so produces warnings
  3531 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3532 for further details.
  3533 
  3534 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3535 bindings for all theorems stored within a given theory; this may help
  3536 in porting non-Isar theories to Isar ones, while keeping ML proof
  3537 scripts for the time being.
  3538 
  3539 * ML operator HTML.with_charset specifies the charset begin used for
  3540 generated HTML files.  For example:
  3541 
  3542   HTML.with_charset "utf-8" use_thy "Hebrew";
  3543   HTML.with_charset "utf-8" use_thy "Chinese";
  3544 
  3545 
  3546 *** System ***
  3547 
  3548 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3549 isabelle, isatool etc.).
  3550 
  3551 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3552 isatool doc, isatool mkdir, display_drafts etc.).
  3553 
  3554 * isatool usedir: option -f allows specification of the ML file to be
  3555 used by Isabelle; default is ROOT.ML.
  3556 
  3557 * New isatool version outputs the version identifier of the Isabelle
  3558 distribution being used.
  3559 
  3560 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3561 (containing Boolean satisfiability problems) into Isabelle/HOL
  3562 theories.
  3563 
  3564 
  3565 
  3566 New in Isabelle2004 (April 2004)
  3567 --------------------------------
  3568 
  3569 *** General ***
  3570 
  3571 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3572   Replaces linorder.ML.
  3573 
  3574 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3575   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3576   (\<a>...\<z>), are now considered normal letters, and can therefore
  3577   be used anywhere where an ASCII letter (a...zA...Z) has until
  3578   now. COMPATIBILITY: This obviously changes the parsing of some
  3579   terms, especially where a symbol has been used as a binder, say
  3580   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3581   as an identifier.  Fix it by inserting a space around former
  3582   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3583   existing theory and ML files.
  3584 
  3585 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3586 
  3587 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3588   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3589   a normal (but invisible) letter. For multiple letter subscripts repeat
  3590   \<^isub> like this: x\<^isub>1\<^isub>2.
  3591 
  3592 * Pure: There are now sub-/superscripts that can span more than one
  3593   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3594   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3595   superscript. The new control characters are not identifier parts.
  3596 
  3597 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3598   content of "..." to the latex file instead of \isacntrl... . The "..."
  3599   may consist of any printable characters excluding the end bracket >.
  3600 
  3601 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3602   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3603   declare constants "final", which prevents their being given a definition
  3604   later.  It is useful for constants whose behaviour is fixed axiomatically
  3605   rather than definitionally, such as the meta-logic connectives.
  3606 
  3607 * Pure: 'instance' now handles general arities with general sorts
  3608   (i.e. intersections of classes),
  3609 
  3610 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3611   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3612   It can be changed to alter the colors/layout of generated pages.
  3613 
  3614 
  3615 *** Isar ***
  3616 
  3617 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3618   cut_tac, subgoal_tac and thin_tac:
  3619   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3620     locales are no longer forced to write Isar proof scripts.
  3621     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3622     emulations.
  3623   - INCOMPATIBILITY: names of variables to be instantiated may no
  3624     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3625     This is consistent with the instantiation attribute "where".
  3626 
  3627 * Attributes "where" and "of":
  3628   - Now take type variables of instantiated theorem into account when reading
  3629     the instantiation string.  This fixes a bug that caused instantiated
  3630     theorems to have too special types in some circumstances.
  3631   - "where" permits explicit instantiations of type variables.
  3632 
  3633 * Calculation commands "moreover" and "also" no longer interfere with
  3634   current facts ("this"), admitting arbitrary combinations with "then"
  3635   and derived forms.
  3636 
  3637 * Locales:
  3638   - Goal statements involving the context element "includes" no longer
  3639     generate theorems with internal delta predicates (those ending on
  3640     "_axioms") in the premise.
  3641     Resolve particular premise with <locale>.intro to obtain old form.
  3642   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3643     specification and "includes" elements in goal statement.
  3644   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3645     [intro?] and [elim?] (respectively) by default.
  3646   - Experimental command for instantiation of locales in proof contexts:
  3647         instantiate <label>[<attrs>]: <loc>
  3648     Instantiates locale <loc> and adds all its theorems to the current context
  3649     taking into account their attributes.  Label and attrs are optional
  3650     modifiers, like in theorem declarations.  If present, names of
  3651     instantiated theorems are qualified with <label>, and the attributes
  3652     <attrs> are applied after any attributes these theorems might have already.
  3653       If the locale has assumptions, a chained fact of the form
  3654     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3655     are derived.  The command does not support old-style locales declared
  3656     with "locale (open)".
  3657       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3658 
  3659 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3660   (Isar) contexts.
  3661 
  3662 
  3663 *** HOL ***
  3664 
  3665 * Proof import: new image HOL4 contains the imported library from
  3666   the HOL4 system with about 2500 theorems. It is imported by
  3667   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3668   can be used like any other Isabelle image.  See
  3669   HOL/Import/HOL/README for more information.
  3670 
  3671 * Simplifier:
  3672   - Much improved handling of linear and partial orders.
  3673     Reasoners for linear and partial orders are set up for type classes
  3674     "linorder" and "order" respectively, and are added to the default simpset
  3675     as solvers.  This means that the simplifier can build transitivity chains
  3676     to solve goals from the assumptions.
  3677   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3678     of blast or auto after simplification become unnecessary because the goal
  3679     is solved by simplification already.
  3680 
  3681 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3682     all proved in axiomatic type classes for semirings, rings and fields.
  3683 
  3684 * Numerics:
  3685   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3686     now formalized using the Ring_and_Field theory mentioned above.
  3687   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3688     than before, because now they are set up once in a generic manner.
  3689   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3690     Look for the general versions in Ring_and_Field (and Power if they concern
  3691     exponentiation).
  3692 
  3693 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3694 
  3695 * Records:
  3696   - Record types are now by default printed with their type abbreviation
  3697     instead of the list of all field types. This can be configured via
  3698     the reference "print_record_type_abbr".
  3699   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3700     (not enabled by default).
  3701   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3702     EX x. x = sel r to True (not enabled by default).
  3703   - Tactic "record_split_simp_tac" to split and simplify records added.
  3704 
  3705 * 'specification' command added, allowing for definition by
  3706   specification.  There is also an 'ax_specification' command that
  3707   introduces the new constants axiomatically.
  3708 
  3709 * arith(_tac) is now able to generate counterexamples for reals as well.
  3710 
  3711 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3712 
  3713 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3714   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3715 
  3716 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3717   matrix theory to linear programming.
  3718 
  3719 * Unions and Intersections:
  3720   The latex output syntax of UN and INT has been changed
  3721   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3722   i.e. the index formulae has become a subscript.
  3723   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3724 
  3725 * Unions and Intersections over Intervals:
  3726   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3727   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3728   like in normal math, and corresponding versions for < and for intersection.
  3729 
  3730 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3731   lexicographic dictonary ordering has been added as "lexord".
  3732 
  3733 * ML: the legacy theory structures Int and List have been removed. They had
  3734   conflicted with ML Basis Library structures having the same names.
  3735 
  3736 * 'refute' command added to search for (finite) countermodels.  Only works
  3737   for a fragment of HOL.  The installation of an external SAT solver is
  3738   highly recommended.  See "HOL/Refute.thy" for details.
  3739 
  3740 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3741   formulae under an assignment of free variables to random values.
  3742   In contrast to 'refute', it can deal with inductive datatypes,
  3743   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3744   for examples.
  3745 
  3746 
  3747 *** HOLCF ***
  3748 
  3749 * Streams now come with concatenation and are part of the HOLCF image
  3750 
  3751 
  3752 
  3753 New in Isabelle2003 (May 2003)
  3754 ------------------------------
  3755 
  3756 *** General ***
  3757 
  3758 * Provers/simplifier:
  3759 
  3760   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3761     Assumptions are now subject to complete mutual simplification,
  3762     not just from left to right. The simplifier now preserves
  3763     the order of assumptions.
  3764 
  3765     Potential INCOMPATIBILITY:
  3766 
  3767     -- simp sometimes diverges where the old version did
  3768        not, e.g. invoking simp on the goal
  3769 
  3770         [| P (f x); y = x; f x = f y |] ==> Q
  3771 
  3772        now gives rise to the infinite reduction sequence
  3773 
  3774         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3775 
  3776        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3777        kind of problem.
  3778 
  3779     -- Tactics combining classical reasoner and simplification (such as auto)
  3780        are also affected by this change, because many of them rely on
  3781        simp. They may sometimes diverge as well or yield a different numbers
  3782        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3783        in case of problems. Sometimes subsequent calls to the classical
  3784        reasoner will fail because a preceeding call to the simplifier too
  3785        eagerly simplified the goal, e.g. deleted redundant premises.
  3786 
  3787   - The simplifier trace now shows the names of the applied rewrite rules
  3788 
  3789   - You can limit the number of recursive invocations of the simplifier
  3790     during conditional rewriting (where the simplifie tries to solve the
  3791     conditions before applying the rewrite rule):
  3792     ML "simp_depth_limit := n"
  3793     where n is an integer. Thus you can force termination where previously
  3794     the simplifier would diverge.
  3795 
  3796   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3797 
  3798   - No longer aborts on failed congruence proof.  Instead, the
  3799     congruence is ignored.
  3800 
  3801 * Pure: New generic framework for extracting programs from constructive
  3802   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3803   as HOL/Extraction for some case studies.
  3804 
  3805 * Pure: The main goal of the proof state is no longer shown by default, only
  3806 the subgoals. This behaviour is controlled by a new flag.
  3807    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3808 (ML: Proof.show_main_goal).
  3809 
  3810 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3811 rules whose conclusion matches subgoal 1:
  3812       PG menu: Isabelle/Isar -> Show me -> matching rules
  3813 The rules are ordered by how closely they match the subgoal.
  3814 In particular, rules that solve a subgoal outright are displayed first
  3815 (or rather last, the way they are printed).
  3816 (ML: ProofGeneral.print_intros())
  3817 
  3818 * Pure: New flag trace_unify_fail causes unification to print
  3819 diagnostic information (PG: in trace buffer) when it fails. This is
  3820 useful for figuring out why single step proofs like rule, erule or
  3821 assumption failed.
  3822 
  3823 * Pure: Locale specifications now produce predicate definitions
  3824 according to the body of text (covering assumptions modulo local
  3825 definitions); predicate "loc_axioms" covers newly introduced text,
  3826 while "loc" is cumulative wrt. all included locale expressions; the
  3827 latter view is presented only on export into the global theory
  3828 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3829 on the old view without predicates;
  3830 
  3831 * Pure: predefined locales "var" and "struct" are useful for sharing
  3832 parameters (as in CASL, for example); just specify something like
  3833 ``var x + var y + struct M'' as import;
  3834 
  3835 * Pure: improved thms_containing: proper indexing of facts instead of
  3836 raw theorems; check validity of results wrt. current name space;
  3837 include local facts of proof configuration (also covers active
  3838 locales), cover fixed variables in index; may use "_" in term
  3839 specification; an optional limit for the number of printed facts may
  3840 be given (the default is 40);
  3841 
  3842 * Pure: disallow duplicate fact bindings within new-style theory files
  3843 (batch-mode only);
  3844 
  3845 * Provers: improved induct method: assumptions introduced by case
  3846 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3847 the goal statement); "foo" still refers to all facts collectively;
  3848 
  3849 * Provers: the function blast.overloaded has been removed: all constants
  3850 are regarded as potentially overloaded, which improves robustness in exchange
  3851 for slight decrease in efficiency;
  3852 
  3853 * Provers/linorder: New generic prover for transitivity reasoning over
  3854 linear orders.  Note: this prover is not efficient!
  3855 
  3856 * Isar: preview of problems to finish 'show' now produce an error
  3857 rather than just a warning (in interactive mode);
  3858 
  3859 
  3860 *** HOL ***
  3861 
  3862 * arith(_tac)
  3863 
  3864  - Produces a counter example if it cannot prove a goal.
  3865    Note that the counter example may be spurious if the goal is not a formula
  3866    of quantifier-free linear arithmetic.
  3867    In ProofGeneral the counter example appears in the trace buffer.
  3868 
  3869  - Knows about div k and mod k where k is a numeral of type nat or int.
  3870 
  3871  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3872    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3873    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3874 
  3875 * simp's arithmetic capabilities have been enhanced a bit: it now
  3876 takes ~= in premises into account (by performing a case split);
  3877 
  3878 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3879 are distributed over a sum of terms;
  3880 
  3881 * New tactic "trans_tac" and method "trans" instantiate
  3882 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3883 "<=", "<" and "=").
  3884 
  3885 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3886 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3887 
  3888 * 'typedef' command has new option "open" to suppress the set
  3889 definition;
  3890 
  3891 * functions Min and Max on finite sets have been introduced (theory
  3892 Finite_Set);
  3893 
  3894 * attribute [symmetric] now works for relations as well; it turns
  3895 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3896 
  3897 * induct over a !!-quantified statement (say !!x1..xn):
  3898   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3899 
  3900 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3901 %x. None. Warning: empty_def now refers to the previously hidden definition
  3902 of the empty set.
  3903 
  3904 * Algebra: formalization of classical algebra.  Intended as base for
  3905 any algebraic development in Isabelle.  Currently covers group theory
  3906 (up to Sylow's theorem) and ring theory (Universal Property of
  3907 Univariate Polynomials).  Contributions welcome;
  3908 
  3909 * GroupTheory: deleted, since its material has been moved to Algebra;
  3910 
  3911 * Complex: new directory of the complex numbers with numeric constants,
  3912 nonstandard complex numbers, and some complex analysis, standard and
  3913 nonstandard (Jacques Fleuriot);
  3914 
  3915 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3916 
  3917 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3918 Fleuriot);
  3919 
  3920 * Real/HahnBanach: updated and adapted to locales;
  3921 
  3922 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3923 Gray and Kramer);
  3924 
  3925 * UNITY: added the Meier-Sanders theory of progress sets;
  3926 
  3927 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3928 as abstract algorithms, instantiated to the JVM;
  3929 
  3930 * Bali: Java source language formalization. Type system, operational
  3931 semantics, axiomatic semantics. Supported language features:
  3932 classes, interfaces, objects,virtual methods, static methods,
  3933 static/instance fields, arrays, access modifiers, definite
  3934 assignment, exceptions.
  3935 
  3936 
  3937 *** ZF ***
  3938 
  3939 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3940 universe, etc.);
  3941 
  3942 * Main ZF: virtually all theories converted to new-style format;
  3943 
  3944 
  3945 *** ML ***
  3946 
  3947 * Pure: Tactic.prove provides sane interface for internal proofs;
  3948 omits the infamous "standard" operation, so this is more appropriate
  3949 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3950 
  3951 * Pure: improved error reporting of simprocs;
  3952 
  3953 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3954 up simprocs;
  3955 
  3956 
  3957 *** Document preparation ***
  3958 
  3959 * uses \par instead of \\ for line breaks in theory text. This may
  3960 shift some page breaks in large documents. To get the old behaviour
  3961 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3962 
  3963 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3964 other packages
  3965 
  3966 * \<euro> now needs package babel/greek instead of marvosym (which
  3967 broke \Rightarrow)
  3968 
  3969 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3970 textcomp package)
  3971 
  3972 
  3973 
  3974 New in Isabelle2002 (March 2002)
  3975 --------------------------------
  3976 
  3977 *** Document preparation ***
  3978 
  3979 * greatly simplified document preparation setup, including more
  3980 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3981 instructive isatool mkdir; users should basically be able to get
  3982 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3983 users may run a separate document processing stage manually like this:
  3984 "isatool usedir -D output HOL Test && isatool document Test/output";
  3985 
  3986 * theory dependency graph may now be incorporated into documents;
  3987 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3988 with \includegraphics of LaTeX;
  3989 
  3990 * proper spacing of consecutive markup elements, especially text
  3991 blocks after section headings;
  3992 
  3993 * support bold style (for single symbols only), input syntax is like
  3994 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3995 
  3996 * \<bullet> is now output as bold \cdot by default, which looks much
  3997 better in printed text;
  3998 
  3999 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4000 note that these symbols are currently unavailable in Proof General /
  4001 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4002 
  4003 * isatool latex no longer depends on changed TEXINPUTS, instead
  4004 isatool document copies the Isabelle style files to the target
  4005 location;
  4006 
  4007 
  4008 *** Isar ***
  4009 
  4010 * Pure/Provers: improved proof by cases and induction;
  4011   - 'case' command admits impromptu naming of parameters (such as
  4012     "case (Suc n)");
  4013   - 'induct' method divinates rule instantiation from the inductive
  4014     claim; no longer requires excessive ?P bindings for proper
  4015     instantiation of cases;
  4016   - 'induct' method properly enumerates all possibilities of set/type
  4017     rules; as a consequence facts may be also passed through *type*
  4018     rules without further ado;
  4019   - 'induct' method now derives symbolic cases from the *rulified*
  4020     rule (before it used to rulify cases stemming from the internal
  4021     atomized version); this means that the context of a non-atomic
  4022     statement becomes is included in the hypothesis, avoiding the
  4023     slightly cumbersome show "PROP ?case" form;
  4024   - 'induct' may now use elim-style induction rules without chaining
  4025     facts, using ``missing'' premises from the goal state; this allows
  4026     rules stemming from inductive sets to be applied in unstructured
  4027     scripts, while still benefitting from proper handling of non-atomic
  4028     statements; NB: major inductive premises need to be put first, all
  4029     the rest of the goal is passed through the induction;
  4030   - 'induct' proper support for mutual induction involving non-atomic
  4031     rule statements (uses the new concept of simultaneous goals, see
  4032     below);
  4033   - append all possible rule selections, but only use the first
  4034     success (no backtracking);
  4035   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4036   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4037   - added 'print_induct_rules' (covered by help item in recent Proof
  4038     General versions);
  4039   - moved induct/cases attributes to Pure, methods to Provers;
  4040   - generic method setup instantiated for FOL and HOL;
  4041 
  4042 * Pure: support multiple simultaneous goal statements, for example
  4043 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4044 meta-level mechanism, this acts as if several individual goals had
  4045 been stated separately; in particular common proof methods need to be
  4046 repeated in order to cover all claims; note that a single elimination
  4047 step is *not* sufficient to establish the two conjunctions, so this
  4048 fails:
  4049 
  4050   assume "A & B" then have A and B ..   (*".." fails*)
  4051 
  4052 better use "obtain" in situations as above; alternative refer to
  4053 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4054 
  4055 * Pure: proper integration with ``locales''; unlike the original
  4056 version by Florian Kammller, Isar locales package high-level proof
  4057 contexts rather than raw logical ones (e.g. we admit to include
  4058 attributes everywhere); operations on locales include merge and
  4059 rename; support for implicit arguments (``structures''); simultaneous
  4060 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4061 some examples;
  4062 
  4063 * Pure: the following commands have been ``localized'', supporting a
  4064 target locale specification "(in name)": 'lemma', 'theorem',
  4065 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4066 stored both within the locale and at the theory level (exported and
  4067 qualified by the locale name);
  4068 
  4069 * Pure: theory goals may now be specified in ``long'' form, with
  4070 ad-hoc contexts consisting of arbitrary locale elements. for example
  4071 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4072 definitions may be given, too); the result is a meta-level rule with
  4073 the context elements being discharged in the obvious way;
  4074 
  4075 * Pure: new proof command 'using' allows to augment currently used
  4076 facts after a goal statement ('using' is syntactically analogous to
  4077 'apply', but acts on the goal's facts only); this allows chained facts
  4078 to be separated into parts given before and after a claim, as in
  4079 ``from a and b have C using d and e <proof>'';
  4080 
  4081 * Pure: renamed "antecedent" case to "rule_context";
  4082 
  4083 * Pure: new 'judgment' command records explicit information about the
  4084 object-logic embedding (used by several tools internally); no longer
  4085 use hard-wired "Trueprop";
  4086 
  4087 * Pure: added 'corollary' command;
  4088 
  4089 * Pure: fixed 'token_translation' command;
  4090 
  4091 * Pure: removed obsolete 'exported' attribute;
  4092 
  4093 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4094 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4095 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4096 
  4097 * Pure: method 'atomize' presents local goal premises as object-level
  4098 statements (atomic meta-level propositions); setup controlled via
  4099 rewrite rules declarations of 'atomize' attribute; example
  4100 application: 'induct' method with proper rule statements in improper
  4101 proof *scripts*;
  4102 
  4103 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4104 now consider the syntactic context of assumptions, giving a better
  4105 chance to get type-inference of the arguments right (this is
  4106 especially important for locales);
  4107 
  4108 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4109 mode;
  4110 
  4111 * Pure/obtain: the formal conclusion "thesis", being marked as
  4112 ``internal'', may no longer be reference directly in the text;
  4113 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4114 situations;
  4115 
  4116 * Pure: generic 'sym' attribute which declares a rule both as pure
  4117 'elim?' and for the 'symmetric' operation;
  4118 
  4119 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4120 text; the fixed correlation with particular command syntax has been
  4121 discontinued;
  4122 
  4123 * Pure: new method 'rules' is particularly well-suited for proof
  4124 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4125 but often produces more compact proof terms with less detours;
  4126 
  4127 * Pure/Provers/classical: simplified integration with pure rule
  4128 attributes and methods; the classical "intro?/elim?/dest?"
  4129 declarations coincide with the pure ones; the "rule" method no longer
  4130 includes classically swapped intros; "intro" and "elim" methods no
  4131 longer pick rules from the context; also got rid of ML declarations
  4132 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4133 INCOMPATIBILITY;
  4134 
  4135 * Provers/classical: attribute 'swapped' produces classical inversions
  4136 of introduction rules;
  4137 
  4138 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4139 rules instead of full simplifier context; 'iff' attribute handles
  4140 conditional rules;
  4141 
  4142 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4143 
  4144 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4145 "(permissive)" option to recover old behavior;
  4146 
  4147 * HOL: 'inductive' no longer features separate (collective) attributes
  4148 for 'intros' (was found too confusing);
  4149 
  4150 * HOL: properly declared induction rules less_induct and
  4151 wf_induct_rule;
  4152 
  4153 
  4154 *** HOL ***
  4155 
  4156 * HOL: moved over to sane numeral syntax; the new policy is as
  4157 follows:
  4158 
  4159   - 0 and 1 are polymorphic constants, which are defined on any
  4160   numeric type (nat, int, real etc.);
  4161 
  4162   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4163   binary representation internally;
  4164 
  4165   - type nat has special constructor Suc, and generally prefers Suc 0
  4166   over 1::nat and Suc (Suc 0) over 2::nat;
  4167 
  4168 This change may cause significant problems of INCOMPATIBILITY; here
  4169 are some hints on converting existing sources:
  4170 
  4171   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4172   entities, so expressions involving "-" (unary or binary minus) need
  4173   to be spaced properly;
  4174 
  4175   - existing occurrences of "1" may need to be constraint "1::nat" or
  4176   even replaced by Suc 0; similar for old "2";
  4177 
  4178   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4179 
  4180   - remove all special provisions on numerals in proofs;
  4181 
  4182 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4183 representation (depends on bin_arith_simps in the default context);
  4184 
  4185 * HOL: symbolic syntax for x^2 (numeral 2);
  4186 
  4187 * HOL: the class of all HOL types is now called "type" rather than
  4188 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4189 in axclass/classes, instance/arities, and (usually rare) occurrences
  4190 in typings (of consts etc.); internally the class is called
  4191 "HOL.type", ML programs should refer to HOLogic.typeS;
  4192 
  4193 * HOL/record package improvements:
  4194   - new derived operations "fields" to build a partial record section,
  4195     "extend" to promote a fixed record to a record scheme, and
  4196     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4197     declared as simp by default;
  4198   - shared operations ("more", "fields", etc.) now need to be always
  4199     qualified) --- potential INCOMPATIBILITY;
  4200   - removed "make_scheme" operations (use "make" with "extend") --
  4201     INCOMPATIBILITY;
  4202   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4203   - provides cases/induct rules for use with corresponding Isar
  4204     methods (for concrete records, record schemes, concrete more
  4205     parts, and schematic more parts -- in that order);
  4206   - internal definitions directly based on a light-weight abstract
  4207     theory of product types over typedef rather than datatype;
  4208 
  4209 * HOL: generic code generator for generating executable ML code from
  4210 specifications; specific support for HOL constructs such as inductive
  4211 datatypes and sets, as well as recursive functions; can be invoked
  4212 via 'generate_code' theory section;
  4213 
  4214 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4215 
  4216 * HOL: consolidated and renamed several theories.  In particular:
  4217         Ord.thy has been absorbed into HOL.thy
  4218         String.thy has been absorbed into List.thy
  4219 
  4220 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4221 (beware of argument permutation!);
  4222 
  4223 * HOL: linorder_less_split superseded by linorder_cases;
  4224 
  4225 * HOL/List: "nodups" renamed to "distinct";
  4226 
  4227 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4228 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4229   - Ex_def has changed, now need to use some_eq_ex
  4230 
  4231 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4232 in this (rare) case use:
  4233 
  4234   delSWrapper "split_all_tac"
  4235   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4236 
  4237 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4238 MAY FAIL;
  4239 
  4240 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4241 Isabelle's type classes, ^ on functions and relations has too general
  4242 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4243 necessary to attach explicit type constraints;
  4244 
  4245 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4246 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4247 renamed accordingly (eg "compI" -> "rel_compI").
  4248 
  4249 * HOL: syntax translations now work properly with numerals and records
  4250 expressions;
  4251 
  4252 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4253 of "lam" -- INCOMPATIBILITY;
  4254 
  4255 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4256 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4257 renamed "Product_Type.unit";
  4258 
  4259 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4260 
  4261 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4262 the "cases" method);
  4263 
  4264 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4265 Florian Kammller);
  4266 
  4267 * HOL/IMP: updated and converted to new-style theory format; several
  4268 parts turned into readable document, with proper Isar proof texts and
  4269 some explanations (by Gerwin Klein);
  4270 
  4271 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4272 
  4273 * HOL-Hyperreal is now a logic image;
  4274 
  4275 
  4276 *** HOLCF ***
  4277 
  4278 * Isar: consts/constdefs supports mixfix syntax for continuous
  4279 operations;
  4280 
  4281 * Isar: domain package adapted to new-style theory format, e.g. see
  4282 HOLCF/ex/Dnat.thy;
  4283 
  4284 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4285 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4286 lift.induct_tac, always use UU instead of Undef;
  4287 
  4288 * HOLCF/IMP: updated and converted to new-style theory;
  4289 
  4290 
  4291 *** ZF ***
  4292 
  4293 * Isar: proper integration of logic-specific tools and packages,
  4294 including theory commands '(co)inductive', '(co)datatype',
  4295 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4296 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4297 
  4298 * theory Main no longer includes AC; for the Axiom of Choice, base
  4299 your theory on Main_ZFC;
  4300 
  4301 * the integer library now covers quotients and remainders, with many
  4302 laws relating division to addition, multiplication, etc.;
  4303 
  4304 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4305 typeless version of the formalism;
  4306 
  4307 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4308 format;
  4309 
  4310 * ZF/Induct: new directory for examples of inductive definitions,
  4311 including theory Multiset for multiset orderings; converted to
  4312 new-style theory format;
  4313 
  4314 * ZF: many new theorems about lists, ordinals, etc.;
  4315 
  4316 
  4317 *** General ***
  4318 
  4319 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4320 variable proof controls level of detail: 0 = no proofs (only oracle
  4321 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4322 also ref manual for further ML interfaces;
  4323 
  4324 * Pure/axclass: removed obsolete ML interface
  4325 goal_subclass/goal_arity;
  4326 
  4327 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4328 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4329 separate tokens, so expressions involving minus need to be spaced
  4330 properly;
  4331 
  4332 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4333 rather than "infixl" or "infixr";
  4334 
  4335 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4336 sort constraint specifications in type inference; e.g. "x::_::foo"
  4337 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4338 type variable);
  4339 
  4340 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4341 control output of nested => (types); the default behavior is
  4342 "type_brackets";
  4343 
  4344 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4345 tokens into AST constants;
  4346 
  4347 * Pure/syntax: prefer later declarations of translations and print
  4348 translation functions; potential INCOMPATIBILITY: need to reverse
  4349 multiple declarations for same syntax element constant;
  4350 
  4351 * Pure/show_hyps reset by default (in accordance to existing Isar
  4352 practice);
  4353 
  4354 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4355 addSafter;
  4356 
  4357 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4358 as well;
  4359 
  4360 * system: tested support for MacOS X; should be able to get Isabelle +
  4361 Proof General to work in a plain Terminal after installing Poly/ML
  4362 (e.g. from the Isabelle distribution area) and GNU bash alone
  4363 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4364 support requires further installations, e.g. from
  4365 http://fink.sourceforge.net/);
  4366 
  4367 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4368 
  4369 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4370 of 40 MB), cf. ML_OPTIONS;
  4371 
  4372 * system: Proof General keywords specification is now part of the
  4373 Isabelle distribution (see etc/isar-keywords.el);
  4374 
  4375 * system: support for persistent Proof General sessions (refrain from
  4376 outdating all loaded theories on startup); user may create writable
  4377 logic images like this: ``isabelle -q HOL Test'';
  4378 
  4379 * system: smart selection of Isabelle process versus Isabelle
  4380 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4381 run both "isabelle" and "Isabelle" even if file names are badly
  4382 damaged (executable inspects the case of the first letter of its own
  4383 name); added separate "isabelle-process" and "isabelle-interface";
  4384 
  4385 * system: refrain from any attempt at filtering input streams; no
  4386 longer support ``8bit'' encoding of old isabelle font, instead proper
  4387 iso-latin characters may now be used; the related isatools
  4388 "symbolinput" and "nonascii" have disappeared as well;
  4389 
  4390 * system: removed old "xterm" interface (the print modes "xterm" and
  4391 "xterm_color" are still available for direct use in a suitable
  4392 terminal);
  4393 
  4394 
  4395 
  4396 New in Isabelle99-2 (February 2001)
  4397 -----------------------------------
  4398 
  4399 *** Overview of INCOMPATIBILITIES ***
  4400 
  4401 * HOL: please note that theories in the Library and elsewhere often use the
  4402 new-style (Isar) format; to refer to their theorems in an ML script you must
  4403 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4404 
  4405 * HOL: inductive package no longer splits induction rule aggressively,
  4406 but only as far as specified by the introductions given; the old
  4407 format may be recovered via ML function complete_split_rule or attribute
  4408 'split_rule (complete)';
  4409 
  4410 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4411 gfp_Tarski to gfp_unfold;
  4412 
  4413 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4414 
  4415 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4416 relation); infix "^^" has been renamed "``"; infix "``" has been
  4417 renamed "`"; "univalent" has been renamed "single_valued";
  4418 
  4419 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4420 operation;
  4421 
  4422 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4423 
  4424 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4425 
  4426 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4427 consequence, it is no longer monotonic wrt. the local goal context
  4428 (which is now passed through the inductive cases);
  4429 
  4430 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4431 \<gg> to \<ggreater>;
  4432 
  4433 
  4434 *** Document preparation ***
  4435 
  4436 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4437 available: are "it" for near math-mode best-style output, "sl" for
  4438 slanted text style, and "tt" for plain type-writer; if no
  4439 \isabellestyle command is given, output is according to slanted
  4440 type-writer);
  4441 
  4442 * support sub/super scripts (for single symbols only), input syntax is
  4443 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4444 
  4445 * some more standard symbols; see Appendix A of the system manual for
  4446 the complete list of symbols defined in isabellesym.sty;
  4447 
  4448 * improved isabelle style files; more abstract symbol implementation
  4449 (should now use \isamath{...} and \isatext{...} in custom symbol
  4450 definitions);
  4451 
  4452 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4453 state; Note that presentation of goal states does not conform to
  4454 actual human-readable proof documents.  Please do not include goal
  4455 states into document output unless you really know what you are doing!
  4456 
  4457 * proper indentation of antiquoted output with proportional LaTeX
  4458 fonts;
  4459 
  4460 * no_document ML operator temporarily disables LaTeX document
  4461 generation;
  4462 
  4463 * isatool unsymbolize tunes sources for plain ASCII communication;
  4464 
  4465 
  4466 *** Isar ***
  4467 
  4468 * Pure: Isar now suffers initial goal statements to contain unbound
  4469 schematic variables (this does not conform to actual readable proof
  4470 documents, due to unpredictable outcome and non-compositional proof
  4471 checking); users who know what they are doing may use schematic goals
  4472 for Prolog-style synthesis of proven results;
  4473 
  4474 * Pure: assumption method (an implicit finishing) now handles actual
  4475 rules as well;
  4476 
  4477 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4478 initial goal, declare "that" only as Pure intro (only for single
  4479 steps); the "that" rule assumption may now be involved in implicit
  4480 finishing, thus ".." becomes a feasible for trivial obtains;
  4481 
  4482 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4483 instance proofs may be performed by "..";
  4484 
  4485 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4486 statements as well;
  4487 
  4488 * Pure: more robust selection of calculational rules;
  4489 
  4490 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4491 rule (as well as the assumption rule);
  4492 
  4493 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4494 lemmas, using the graph browser tool;
  4495 
  4496 * Pure: predict failure of "show" in interactive mode;
  4497 
  4498 * Pure: 'thms_containing' now takes actual terms as arguments;
  4499 
  4500 * HOL: improved method 'induct' --- now handles non-atomic goals
  4501 (potential INCOMPATIBILITY); tuned error handling;
  4502 
  4503 * HOL: cases and induct rules now provide explicit hints about the
  4504 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4505 any remaining facts are inserted into the goal verbatim;
  4506 
  4507 * HOL: local contexts (aka cases) may now contain term bindings as
  4508 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4509 the result to be shown in each case;
  4510 
  4511 * HOL: added 'recdef_tc' command;
  4512 
  4513 * isatool convert assists in eliminating legacy ML scripts;
  4514 
  4515 
  4516 *** HOL ***
  4517 
  4518 * HOL/Library: a collection of generic theories to be used together
  4519 with main HOL; the theory loader path already includes this directory
  4520 by default; the following existing theories have been moved here:
  4521 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4522 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4523 
  4524 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4525 modelling and verification task performed in Isabelle/HOL +
  4526 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4527 
  4528 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4529 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4530 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4531 'domain', this makes the theory consistent with mathematical
  4532 literature;
  4533 
  4534 * HOL basics: added overloaded operations "inverse" and "divide"
  4535 (infix "/"), syntax for generic "abs" operation, generic summation
  4536 operator \<Sum>;
  4537 
  4538 * HOL/typedef: simplified package, provide more useful rules (see also
  4539 HOL/subset.thy);
  4540 
  4541 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4542 now expressed as a proper nested rule (old-style tactic scripts may
  4543 require atomize_strip_tac to cope with non-atomic premises);
  4544 
  4545 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4546 to "split_conv" (old name still available for compatibility);
  4547 
  4548 * HOL: improved concrete syntax for strings (e.g. allows translation
  4549 rules with string literals);
  4550 
  4551 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4552  and Fleuriot's mechanization of analysis, including the transcendental
  4553  functions for the reals;
  4554 
  4555 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4556 
  4557 
  4558 *** CTT ***
  4559 
  4560 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4561 "lam" is displayed as TWO lambda-symbols
  4562 
  4563 * CTT: theory Main now available, containing everything (that is, Bool
  4564 and Arith);
  4565 
  4566 
  4567 *** General ***
  4568 
  4569 * Pure: the Simplifier has been implemented properly as a derived rule
  4570 outside of the actual kernel (at last!); the overall performance
  4571 penalty in practical applications is about 50%, while reliability of
  4572 the Isabelle inference kernel has been greatly improved;
  4573 
  4574 * print modes "brackets" and "no_brackets" control output of nested =>
  4575 (types) and ==> (props); the default behaviour is "brackets";
  4576 
  4577 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4578 as assumptions as well;
  4579 
  4580 * system: support Poly/ML 4.0;
  4581 
  4582 * system: isatool install handles KDE version 1 or 2;
  4583 
  4584 
  4585 
  4586 New in Isabelle99-1 (October 2000)
  4587 ----------------------------------
  4588 
  4589 *** Overview of INCOMPATIBILITIES ***
  4590 
  4591 * HOL: simplification of natural numbers is much changed; to partly
  4592 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4593 issue the following ML commands:
  4594 
  4595   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4596   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4597 
  4598 * HOL: simplification no longer dives into case-expressions; this is
  4599 controlled by "t.weak_case_cong" for each datatype t;
  4600 
  4601 * HOL: nat_less_induct renamed to less_induct;
  4602 
  4603 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4604 fixsome to patch .thy and .ML sources automatically;
  4605 
  4606   select_equality  -> some_equality
  4607   select_eq_Ex     -> some_eq_ex
  4608   selectI2EX       -> someI2_ex
  4609   selectI2         -> someI2
  4610   selectI          -> someI
  4611   select1_equality -> some1_equality
  4612   Eps_sym_eq       -> some_sym_eq_trivial
  4613   Eps_eq           -> some_eq_trivial
  4614 
  4615 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4616 
  4617 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4618 instead);
  4619 
  4620 * HOL: the recursion equations generated by 'recdef' are now called
  4621 f.simps instead of f.rules;
  4622 
  4623 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4624 
  4625 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4626 sometimes be needed;
  4627 
  4628 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4629 
  4630 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4631 
  4632 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4633 product is now "<*>" instead of "Times"; the lexicographic product is
  4634 now "<*lex*>" instead of "**";
  4635 
  4636 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4637 of main HOL, but was unused); better use HOL's datatype package;
  4638 
  4639 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4640 the old syntax may be recovered as follows:
  4641 
  4642   syntax (symbols)
  4643     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4644       (infixl "\\<oplus>" 100)
  4645 
  4646 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4647 
  4648 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4649 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4650 internally;
  4651 
  4652 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4653 changed from A/r to A//r;
  4654 
  4655 * ZF: new treatment of arithmetic (nat & int) may break some old
  4656 proofs;
  4657 
  4658 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4659 rulify -> rule_format, elimify -> elim_format, ...);
  4660 
  4661 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4662 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4663 should have to change intro!! to intro? only); replaced "delrule" by
  4664 "rule del";
  4665 
  4666 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4667 
  4668 * Provers: strengthened force_tac by using new first_best_tac;
  4669 
  4670 * LaTeX document preparation: several changes of isabelle.sty (see
  4671 lib/texinputs);
  4672 
  4673 
  4674 *** Document preparation ***
  4675 
  4676 * formal comments (text blocks etc.) in new-style theories may now
  4677 contain antiquotations of thm/prop/term/typ/text to be presented
  4678 according to latex print mode; concrete syntax is like this:
  4679 @{term[show_types] "f(x) = a + x"};
  4680 
  4681 * isatool mkdir provides easy setup of Isabelle session directories,
  4682 including proper document sources;
  4683 
  4684 * generated LaTeX sources are now deleted after successful run
  4685 (isatool document -c); may retain a copy somewhere else via -D option
  4686 of isatool usedir;
  4687 
  4688 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4689 style files, achieving self-contained LaTeX sources and simplifying
  4690 LaTeX debugging;
  4691 
  4692 * old-style theories now produce (crude) LaTeX output as well;
  4693 
  4694 * browser info session directories are now self-contained (may be put
  4695 on WWW server seperately); improved graphs of nested sessions; removed
  4696 graph for 'all sessions';
  4697 
  4698 * several improvements in isabelle style files; \isabellestyle{it}
  4699 produces fake math mode output; \isamarkupheader is now \section by
  4700 default; see lib/texinputs/isabelle.sty etc.;
  4701 
  4702 
  4703 *** Isar ***
  4704 
  4705 * Isar/Pure: local results and corresponding term bindings are now
  4706 subject to Hindley-Milner polymorphism (similar to ML); this
  4707 accommodates incremental type-inference very nicely;
  4708 
  4709 * Isar/Pure: new derived language element 'obtain' supports
  4710 generalized existence reasoning;
  4711 
  4712 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4713 support accumulation of results, without applying any rules yet;
  4714 useful to collect intermediate results without explicit name
  4715 references, and for use with transitivity rules with more than 2
  4716 premises;
  4717 
  4718 * Isar/Pure: scalable support for case-analysis type proofs: new
  4719 'case' language element refers to local contexts symbolically, as
  4720 produced by certain proof methods; internally, case names are attached
  4721 to theorems as "tags";
  4722 
  4723 * Isar/Pure: theory command 'hide' removes declarations from
  4724 class/type/const name spaces;
  4725 
  4726 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4727 indicate potential overloading;
  4728 
  4729 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4730 
  4731 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4732 "{a,b,c}" instead of {a,b,c};
  4733 
  4734 * Isar/Pure now provides its own version of intro/elim/dest
  4735 attributes; useful for building new logics, but beware of confusion
  4736 with the version in Provers/classical;
  4737 
  4738 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4739 case name 'antecedent';
  4740 
  4741 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4742 to the current context is now done automatically);
  4743 
  4744 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4745 for definining proof methods in ML;
  4746 
  4747 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4748 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4749 most cases, one should have to change intro!! to intro? only);
  4750 replaced "delrule" by "rule del";
  4751 
  4752 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4753 'symmetric' attribute (the latter supercedes [RS sym]);
  4754 
  4755 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4756 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4757 well (including splits);
  4758 
  4759 * Isar/Provers: Simplifier and Classical methods now support all kind
  4760 of modifiers used in the past, including 'cong', 'iff', etc.
  4761 
  4762 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4763 of Simplifier and Classical reasoner);
  4764 
  4765 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4766 now support named cases; major packages (inductive, datatype, primrec,
  4767 recdef) support case names and properly name parameters;
  4768 
  4769 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4770 monotonicity conditions are extracted to be proven at end of
  4771 calculations;
  4772 
  4773 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4774 method anyway;
  4775 
  4776 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4777 split_if split_if_asm; datatype package provides theorems foo.splits =
  4778 foo.split foo.split_asm for each datatype;
  4779 
  4780 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4781 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4782 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4783 use "(cases (simplified))" method in proper proof texts);
  4784 
  4785 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4786 
  4787 * Isar: names of theorems etc. may be natural numbers as well;
  4788 
  4789 * Isar: 'pr' command: optional arguments for goals_limit and
  4790 ProofContext.prems_limit; no longer prints theory contexts, but only
  4791 proof states;
  4792 
  4793 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4794 additional print modes to be specified; e.g. "pr(latex)" will print
  4795 proof state according to the Isabelle LaTeX style;
  4796 
  4797 * Isar: improved support for emulating tactic scripts, including proof
  4798 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4799 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4800 (for HOL datatypes);
  4801 
  4802 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4803 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4804 'proof method scripts' have to be in depth-first order;
  4805 
  4806 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4807 
  4808 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4809 should instead use individual commands for printing items
  4810 (print_commands, print_methods etc.);
  4811 
  4812 * Isar: added 'nothing' --- the empty list of theorems;
  4813 
  4814 
  4815 *** HOL ***
  4816 
  4817 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4818 corresponding virtual machine and a specification of its bytecode
  4819 verifier and a lightweight bytecode verifier, including proofs of
  4820 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4821 Cornelia Pusch (see also the homepage of project Bali at
  4822 http://isabelle.in.tum.de/Bali/);
  4823 
  4824 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4825 Clemens Ballarin;
  4826 
  4827 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4828 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4829 Rasmussen;
  4830 
  4831 * HOL/Lattice: fundamental concepts of lattice theory and order
  4832 structures, including duals, properties of bounds versus algebraic
  4833 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4834 Theorem for complete lattices etc.; may also serve as a demonstration
  4835 for abstract algebraic reasoning using axiomatic type classes, and
  4836 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4837 
  4838 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4839 von Oheimb;
  4840 
  4841 * HOL/IMPP: extension of IMP with local variables and mutually
  4842 recursive procedures, by David von Oheimb;
  4843 
  4844 * HOL/Lambda: converted into new-style theory and document;
  4845 
  4846 * HOL/ex/Multiquote: example of multiple nested quotations and
  4847 anti-quotations -- basically a generalized version of de-Bruijn
  4848 representation; very useful in avoiding lifting of operations;
  4849 
  4850 * HOL/record: added general record equality rule to simpset; fixed
  4851 select-update simplification procedure to handle extended records as
  4852 well; admit "r" as field name;
  4853 
  4854 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4855 other numeric types and also as the identity of groups, rings, etc.;
  4856 
  4857 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4858 Types nat and int belong to this axclass;
  4859 
  4860 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4861    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4862    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4863   two terms #m*u and #n*u are replaced by #(m+n)*u
  4864     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4865   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4866     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4867 
  4868 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4869 powerful prover for predicate logic but knows nothing of clasets; see
  4870 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4871 
  4872 * HOL: new version of "case_tac" subsumes both boolean case split and
  4873 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4874 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4875 
  4876 * HOL: simplification no longer dives into case-expressions: only the
  4877 selector expression is simplified, but not the remaining arms; to
  4878 enable full simplification of case-expressions for datatype t, you may
  4879 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4880 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4881 
  4882 * HOL/recdef: the recursion equations generated by 'recdef' for
  4883 function 'f' are now called f.simps instead of f.rules; if all
  4884 termination conditions are proved automatically, these simplification
  4885 rules are added to the simpset, as in primrec; rules may be named
  4886 individually as well, resulting in a separate list of theorems for
  4887 each equation;
  4888 
  4889 * HOL/While is a new theory that provides a while-combinator. It
  4890 permits the definition of tail-recursive functions without the
  4891 provision of a termination measure. The latter is necessary once the
  4892 invariant proof rule for while is applied.
  4893 
  4894 * HOL: new (overloaded) notation for the set of elements below/above
  4895 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4896 
  4897 * HOL: theorems impI, allI, ballI bound as "strip";
  4898 
  4899 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4900 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4901 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4902 
  4903 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4904 
  4905 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4906 main HOL, but was unused);
  4907 
  4908 * HOL: fewer consts declared as global (e.g. have to refer to
  4909 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4910 
  4911 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4912 in case of overlap with user translations (e.g. judgements over
  4913 tuples); (note that the underlying logical represenation is still
  4914 bogus);
  4915 
  4916 
  4917 *** ZF ***
  4918 
  4919 * ZF: simplification automatically cancels common terms in arithmetic
  4920 expressions over nat and int;
  4921 
  4922 * ZF: new treatment of nat to minimize type-checking: all operators
  4923 coerce their operands to a natural number using the function natify,
  4924 making the algebraic laws unconditional;
  4925 
  4926 * ZF: as above, for int: operators coerce their operands to an integer
  4927 using the function intify;
  4928 
  4929 * ZF: the integer library now contains many of the usual laws for the
  4930 orderings, including $<=, and monotonicity laws for $+ and $*;
  4931 
  4932 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4933 simplification;
  4934 
  4935 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4936 to the simplifier and classical reasoner simultaneously;
  4937 
  4938 
  4939 *** General ***
  4940 
  4941 * Provers: blast_tac now handles actual object-logic rules as
  4942 assumptions; note that auto_tac uses blast_tac internally as well;
  4943 
  4944 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4945 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4946 
  4947 * Provers: delrules now handles destruct rules as well (no longer need
  4948 explicit make_elim);
  4949 
  4950 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4951   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4952 use instead the strong form,
  4953   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4954 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4955 from destruct-rules;
  4956 
  4957 * Provers: Simplifier.easy_setup provides a fast path to basic
  4958 Simplifier setup for new object-logics;
  4959 
  4960 * Pure: AST translation rules no longer require constant head on LHS;
  4961 
  4962 * Pure: improved name spaces: ambiguous output is qualified; support
  4963 for hiding of names;
  4964 
  4965 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4966 XSYMBOL_HOME; no longer need to do manual configuration in most
  4967 situations;
  4968 
  4969 * system: compression of ML heaps images may now be controlled via -c
  4970 option of isabelle and isatool usedir (currently only observed by
  4971 Poly/ML);
  4972 
  4973 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4974 useful for remote X11);
  4975 
  4976 * system: provide TAGS file for Isabelle sources;
  4977 
  4978 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4979 order;
  4980 
  4981 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4982 timing flag supersedes proof_timing and Toplevel.trace;
  4983 
  4984 * ML: new combinators |>> and |>>> for incremental transformations
  4985 with secondary results (e.g. certain theory extensions):
  4986 
  4987 * ML: PureThy.add_defs gets additional argument to indicate potential
  4988 overloading (usually false);
  4989 
  4990 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4991 results;
  4992 
  4993 
  4994 
  4995 New in Isabelle99 (October 1999)
  4996 --------------------------------
  4997 
  4998 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4999 
  5000 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5001 are no longer simplified.  (This allows the simplifier to unfold recursive
  5002 functional programs.)  To restore the old behaviour, declare
  5003 
  5004     Delcongs [if_weak_cong];
  5005 
  5006 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5007 complement;
  5008 
  5009 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5010 
  5011 * HOL/datatype: mutual_induct_tac no longer exists --
  5012   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5013 
  5014 * HOL/typedef: fixed type inference for representing set; type
  5015 arguments now have to occur explicitly on the rhs as type constraints;
  5016 
  5017 * ZF: The con_defs part of an inductive definition may no longer refer
  5018 to constants declared in the same theory;
  5019 
  5020 * HOL, ZF: the function mk_cases, generated by the inductive
  5021 definition package, has lost an argument.  To simplify its result, it
  5022 uses the default simpset instead of a supplied list of theorems.
  5023 
  5024 * HOL/List: the constructors of type list are now Nil and Cons;
  5025 
  5026 * Simplifier: the type of the infix ML functions
  5027         setSSolver addSSolver setSolver addSolver
  5028 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5029 for packaging solvers. A solver is created via
  5030         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5031 where the string argument is only a comment.
  5032 
  5033 
  5034 *** Proof tools ***
  5035 
  5036 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5037 decision procedure for linear arithmetic. Currently it is used for
  5038 types `nat', `int', and `real' in HOL (see below); it can, should and
  5039 will be instantiated for other types and logics as well.
  5040 
  5041 * The simplifier now accepts rewrite rules with flexible heads, eg
  5042      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5043   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5044   matching.
  5045 
  5046 
  5047 *** General ***
  5048 
  5049 * New Isabelle/Isar subsystem provides an alternative to traditional
  5050 tactical theorem proving; together with the ProofGeneral/isar user
  5051 interface it offers an interactive environment for developing human
  5052 readable proof documents (Isar == Intelligible semi-automated
  5053 reasoning); for further information see isatool doc isar-ref,
  5054 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5055 
  5056 * improved and simplified presentation of theories: better HTML markup
  5057 (including colors), graph views in several sizes; isatool usedir now
  5058 provides a proper interface for user theories (via -P option); actual
  5059 document preparation based on (PDF)LaTeX is available as well (for
  5060 new-style theories only); see isatool doc system for more information;
  5061 
  5062 * native support for Proof General, both for classic Isabelle and
  5063 Isabelle/Isar;
  5064 
  5065 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5066 using the graph browser tool;
  5067 
  5068 * Isabelle manuals now also available as PDF;
  5069 
  5070 * theory loader rewritten from scratch (may not be fully
  5071 bug-compatible); old loadpath variable has been replaced by show_path,
  5072 add_path, del_path, reset_path functions; new operations such as
  5073 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5074 isatool doc ref);
  5075 
  5076 * improved isatool install: option -k creates KDE application icon,
  5077 option -p DIR installs standalone binaries;
  5078 
  5079 * added ML_PLATFORM setting (useful for cross-platform installations);
  5080 more robust handling of platform specific ML images for SML/NJ;
  5081 
  5082 * the settings environment is now statically scoped, i.e. it is never
  5083 created again in sub-processes invoked from isabelle, isatool, or
  5084 Isabelle;
  5085 
  5086 * path element specification '~~' refers to '$ISABELLE_HOME';
  5087 
  5088 * in locales, the "assumes" and "defines" parts may be omitted if
  5089 empty;
  5090 
  5091 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5092 long arrows);
  5093 
  5094 * new print_mode "HTML";
  5095 
  5096 * new flag show_tags controls display of tags of theorems (which are
  5097 basically just comments that may be attached by some tools);
  5098 
  5099 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5100 mode and goal output format:
  5101 
  5102 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5103 244c244
  5104 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5105 ---
  5106 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5107 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5108 181c181
  5109 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5110 ---
  5111 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5112 
  5113 * function bind_thms stores lists of theorems (cf. bind_thm);
  5114 
  5115 * new shorthand tactics ftac, eatac, datac, fatac;
  5116 
  5117 * qed (and friends) now accept "" as result name; in that case the
  5118 theorem is not stored, but proper checks and presentation of the
  5119 result still apply;
  5120 
  5121 * theorem database now also indexes constants "Trueprop", "all",
  5122 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5123 
  5124 
  5125 *** HOL ***
  5126 
  5127 ** HOL arithmetic **
  5128 
  5129 * There are now decision procedures for linear arithmetic over nat and
  5130 int:
  5131 
  5132 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5133 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5134 are treated as atomic; subformulae not involving type `nat' or `int'
  5135 are ignored; quantified subformulae are ignored unless they are
  5136 positive universal or negative existential. The tactic has to be
  5137 invoked by hand and can be a little bit slow. In particular, the
  5138 running time is exponential in the number of occurrences of `min' and
  5139 `max', and `-' on `nat'.
  5140 
  5141 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5142 (negated) (in)equalities among the premises and the conclusion into
  5143 account (i.e. no compound formulae) and does not know about `min' and
  5144 `max', and `-' on `nat'. It is fast and is used automatically by the
  5145 simplifier.
  5146 
  5147 NB: At the moment, these decision procedures do not cope with mixed
  5148 nat/int formulae where the two parts interact, such as `m < n ==>
  5149 int(m) < int(n)'.
  5150 
  5151 * HOL/Numeral provides a generic theory of numerals (encoded
  5152 efficiently as bit strings); setup for types nat/int/real is in place;
  5153 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5154 int, existing theories and proof scripts may require a few additional
  5155 type constraints;
  5156 
  5157 * integer division and remainder can now be performed on constant
  5158 arguments;
  5159 
  5160 * many properties of integer multiplication, division and remainder
  5161 are now available;
  5162 
  5163 * An interface to the Stanford Validity Checker (SVC) is available through the
  5164 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5165 are proved automatically.  SVC must be installed separately, and its results
  5166 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5167 invocation of the underlying oracle).  For SVC see
  5168   http://verify.stanford.edu/SVC
  5169 
  5170 * IsaMakefile: the HOL-Real target now builds an actual image;
  5171 
  5172 
  5173 ** HOL misc **
  5174 
  5175 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5176 (in Isabelle/Isar) -- by Gertrud Bauer;
  5177 
  5178 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5179 analysis for assembly languages with subtypes;
  5180 
  5181 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5182 -- avoids syntactic ambiguities and treats state, transition, and
  5183 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5184 changed syntax and (many) tactics;
  5185 
  5186 * HOL/inductive: Now also handles more general introduction rules such
  5187   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5188   theorems are now maintained within the theory (maintained via the
  5189   "mono" attribute);
  5190 
  5191 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5192   (using function types) such as
  5193 
  5194   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5195 
  5196 * HOL/record: record_simproc (part of the default simpset) takes care
  5197 of selectors applied to updated records; record_split_tac is no longer
  5198 part of the default claset; update_defs may now be removed from the
  5199 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5200 
  5201   claset_ref () := claset() addSWrapper record_split_wrapper;
  5202   Delsimprocs [record_simproc]
  5203 
  5204 * HOL/typedef: fixed type inference for representing set; type
  5205 arguments now have to occur explicitly on the rhs as type constraints;
  5206 
  5207 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5208 names rather than an ML expression;
  5209 
  5210 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5211 supplied later.  Program schemes can be defined, such as
  5212     "While B C s = (if B s then While B C (C s) else s)"
  5213 where the well-founded relation can be chosen after B and C have been given.
  5214 
  5215 * HOL/List: the constructors of type list are now Nil and Cons;
  5216 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5217 course, ML tools referring to List.list.op # etc. have to be adapted;
  5218 
  5219 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5220 disabled by default; run isabelle with option -m HOL to get back to
  5221 the original Gordon/HOL-style output;
  5222 
  5223 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5224 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5225 
  5226 * HOL basic syntax simplified (more orthogonal): all variants of
  5227 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5228 Eps operator is provided as well: "SOME x. P[x]";
  5229 
  5230 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5231 
  5232 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5233 thus available for user theories;
  5234 
  5235 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5236 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5237 time;
  5238 
  5239 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5240 several times and then mp;
  5241 
  5242 
  5243 *** LK ***
  5244 
  5245 * the notation <<...>> is now available as a notation for sequences of
  5246 formulas;
  5247 
  5248 * the simplifier is now installed
  5249 
  5250 * the axiom system has been generalized (thanks to Soren Heilmann)
  5251 
  5252 * the classical reasoner now has a default rule database
  5253 
  5254 
  5255 *** ZF ***
  5256 
  5257 * new primrec section allows primitive recursive functions to be given
  5258 directly (as in HOL) over datatypes and the natural numbers;
  5259 
  5260 * new tactics induct_tac and exhaust_tac for induction (or case
  5261 analysis) over datatypes and the natural numbers;
  5262 
  5263 * the datatype declaration of type T now defines the recursor T_rec;
  5264 
  5265 * simplification automatically does freeness reasoning for datatype
  5266 constructors;
  5267 
  5268 * automatic type-inference, with AddTCs command to insert new
  5269 type-checking rules;
  5270 
  5271 * datatype introduction rules are now added as Safe Introduction rules
  5272 to the claset;
  5273 
  5274 * the syntax "if P then x else y" is now available in addition to
  5275 if(P,x,y);
  5276 
  5277 
  5278 *** Internal programming interfaces ***
  5279 
  5280 * tuned simplifier trace output; new flag debug_simp;
  5281 
  5282 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5283 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5284 
  5285 * AxClass.axclass_tac lost the theory argument;
  5286 
  5287 * tuned current_goals_markers semantics: begin / end goal avoids
  5288 printing empty lines;
  5289 
  5290 * removed prs and prs_fn hook, which was broken because it did not
  5291 include \n in its semantics, forcing writeln to add one
  5292 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5293 string -> unit if you really want to output text without newline;
  5294 
  5295 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5296 plain output, interface builders may have to enable 'isabelle_font'
  5297 mode to get Isabelle font glyphs as before;
  5298 
  5299 * refined token_translation interface; INCOMPATIBILITY: output length
  5300 now of type real instead of int;
  5301 
  5302 * theory loader actions may be traced via new ThyInfo.add_hook
  5303 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5304 your own database of information attached to *whole* theories -- as
  5305 opposed to intra-theory data slots offered via TheoryDataFun;
  5306 
  5307 * proper handling of dangling sort hypotheses (at last!);
  5308 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5309 extra sort hypotheses that can be witnessed from the type signature;
  5310 the force_strip_shyps flag is gone, any remaining shyps are simply
  5311 left in the theorem (with a warning issued by strip_shyps_warning);
  5312 
  5313 
  5314 
  5315 New in Isabelle98-1 (October 1998)
  5316 ----------------------------------
  5317 
  5318 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5319 
  5320 * several changes of automated proof tools;
  5321 
  5322 * HOL: major changes to the inductive and datatype packages, including
  5323 some minor incompatibilities of theory syntax;
  5324 
  5325 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5326 called `inj_on';
  5327 
  5328 * HOL: removed duplicate thms in Arith:
  5329   less_imp_add_less  should be replaced by  trans_less_add1
  5330   le_imp_add_le      should be replaced by  trans_le_add1
  5331 
  5332 * HOL: unary minus is now overloaded (new type constraints may be
  5333 required);
  5334 
  5335 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5336 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5337 now taken as an integer constant.
  5338 
  5339 * Pure: ML function 'theory_of' renamed to 'theory';
  5340 
  5341 
  5342 *** Proof tools ***
  5343 
  5344 * Simplifier:
  5345   1. Asm_full_simp_tac is now more aggressive.
  5346      1. It will sometimes reorient premises if that increases their power to
  5347         simplify.
  5348      2. It does no longer proceed strictly from left to right but may also
  5349         rotate premises to achieve further simplification.
  5350      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5351      old Asm_full_simp_tac in that it does not rotate premises.
  5352   2. The simplifier now knows a little bit about nat-arithmetic.
  5353 
  5354 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5355 allows for selected deletion of wrappers, by introduction of names for
  5356 wrapper functionals.  This implies that addbefore, addSbefore,
  5357 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5358 and that adding two tactics with the same name overwrites the first
  5359 one (emitting a warning).
  5360   type wrapper = (int -> tactic) -> (int -> tactic)
  5361   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5362   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5363   delWrapper, delSWrapper: claset *  string            -> claset
  5364   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5365 
  5366 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5367 semantics; addbefore now affects only the unsafe part of step_tac
  5368 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5369 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5370 by Force_tac;
  5371 
  5372 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5373 compWrapper; added safe wrapper (and access functions for it);
  5374 
  5375 * HOL/split_all_tac is now much faster and fails if there is nothing
  5376 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5377 and the names of the automatically generated variables have changed.
  5378 split_all_tac has moved within claset() from unsafe wrappers to safe
  5379 wrappers, which means that !!-bound variables are split much more
  5380 aggressively, and safe_tac and clarify_tac now split such variables.
  5381 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5382 Note: the same holds for record_split_tac, which does the job of
  5383 split_all_tac for record fields.
  5384 
  5385 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5386 permanently to the default simpset using Addsplits just like
  5387 Addsimps. They can be removed via Delsplits just like
  5388 Delsimps. Lower-case versions are also available.
  5389 
  5390 * HOL/Simplifier: The rule split_if is now part of the default
  5391 simpset. This means that the simplifier will eliminate all occurrences
  5392 of if-then-else in the conclusion of a goal. To prevent this, you can
  5393 either remove split_if completely from the default simpset by
  5394 `Delsplits [split_if]' or remove it in a specific call of the
  5395 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5396 other case splitting rules to/from the default simpset: every datatype
  5397 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5398 t is the name of the datatype).
  5399 
  5400 * Classical reasoner / Simplifier combination: new force_tac (and
  5401 derivatives Force_tac, force) combines rewriting and classical
  5402 reasoning (and whatever other tools) similarly to auto_tac, but is
  5403 aimed to solve the given subgoal completely.
  5404 
  5405 
  5406 *** General ***
  5407 
  5408 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5409 and `goalw': the theory is no longer needed as an explicit argument -
  5410 the current theory context is used; assumptions are no longer returned
  5411 at the ML-level unless one of them starts with ==> or !!; it is
  5412 recommended to convert to these new commands using isatool fixgoal
  5413 (backup your sources first!);
  5414 
  5415 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5416 the current theory context, and 'theory' to lookup stored theories;
  5417 
  5418 * new theory section 'locale' for declaring constants, assumptions and
  5419 definitions that have local scope;
  5420 
  5421 * new theory section 'nonterminals' for purely syntactic types;
  5422 
  5423 * new theory section 'setup' for generic ML setup functions
  5424 (e.g. package initialization);
  5425 
  5426 * the distribution now includes Isabelle icons: see
  5427 lib/logo/isabelle-{small,tiny}.xpm;
  5428 
  5429 * isatool install - install binaries with absolute references to
  5430 ISABELLE_HOME/bin;
  5431 
  5432 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5433 
  5434 * print mode 'emacs' reserved for Isamode;
  5435 
  5436 * support multiple print (ast) translations per constant name;
  5437 
  5438 * theorems involving oracles are now printed with a suffixed [!];
  5439 
  5440 
  5441 *** HOL ***
  5442 
  5443 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5444 
  5445 * HOL/inductive package reorganized and improved: now supports mutual
  5446 definitions such as
  5447 
  5448   inductive EVEN ODD
  5449     intrs
  5450       null "0 : EVEN"
  5451       oddI "n : EVEN ==> Suc n : ODD"
  5452       evenI "n : ODD ==> Suc n : EVEN"
  5453 
  5454 new theorem list "elims" contains an elimination rule for each of the
  5455 recursive sets; inductive definitions now handle disjunctive premises
  5456 correctly (also ZF);
  5457 
  5458 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5459 "mutual_induct" no longer exists - the induction rule is always
  5460 contained in "induct";
  5461 
  5462 
  5463 * HOL/datatype package re-implemented and greatly improved: now
  5464 supports mutually recursive datatypes such as
  5465 
  5466   datatype
  5467     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5468             | SUM ('a aexp) ('a aexp)
  5469             | DIFF ('a aexp) ('a aexp)
  5470             | NUM 'a
  5471   and
  5472     'a bexp = LESS ('a aexp) ('a aexp)
  5473             | AND ('a bexp) ('a bexp)
  5474             | OR ('a bexp) ('a bexp)
  5475 
  5476 as well as indirectly recursive datatypes such as
  5477 
  5478   datatype
  5479     ('a, 'b) term = Var 'a
  5480                   | App 'b ((('a, 'b) term) list)
  5481 
  5482 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5483 induction on mutually / indirectly recursive datatypes.
  5484 
  5485 Primrec equations are now stored in theory and can be accessed via
  5486 <function_name>.simps.
  5487 
  5488 INCOMPATIBILITIES:
  5489 
  5490   - Theories using datatypes must now have theory Datatype as an
  5491     ancestor.
  5492   - The specific <typename>.induct_tac no longer exists - use the
  5493     generic induct_tac instead.
  5494   - natE has been renamed to nat.exhaust - use exhaust_tac
  5495     instead of res_inst_tac ... natE. Note that the variable
  5496     names in nat.exhaust differ from the names in natE, this
  5497     may cause some "fragile" proofs to fail.
  5498   - The theorems split_<typename>_case and split_<typename>_case_asm
  5499     have been renamed to <typename>.split and <typename>.split_asm.
  5500   - Since default sorts of type variables are now handled correctly,
  5501     some datatype definitions may have to be annotated with explicit
  5502     sort constraints.
  5503   - Primrec definitions no longer require function name and type
  5504     of recursive argument.
  5505 
  5506 Consider using isatool fixdatatype to adapt your theories and proof
  5507 scripts to the new package (backup your sources first!).
  5508 
  5509 
  5510 * HOL/record package: considerably improved implementation; now
  5511 includes concrete syntax for record types, terms, updates; theorems
  5512 for surjective pairing and splitting !!-bound record variables; proof
  5513 support is as follows:
  5514 
  5515   1) standard conversions (selectors or updates applied to record
  5516 constructor terms) are part of the standard simpset;
  5517 
  5518   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5519 made part of standard simpset and claset via addIffs;
  5520 
  5521   3) a tactic for record field splitting (record_split_tac) is part of
  5522 the standard claset (addSWrapper);
  5523 
  5524 To get a better idea about these rules you may retrieve them via
  5525 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5526 the name of your record type.
  5527 
  5528 The split tactic 3) conceptually simplifies by the following rule:
  5529 
  5530   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5531 
  5532 Thus any record variable that is bound by meta-all will automatically
  5533 blow up into some record constructor term, consequently the
  5534 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5535 solve record problems automatically.
  5536 
  5537 
  5538 * reorganized the main HOL image: HOL/Integ and String loaded by
  5539 default; theory Main includes everything;
  5540 
  5541 * automatic simplification of integer sums and comparisons, using cancellation;
  5542 
  5543 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5544 
  5545 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5546 
  5547 * many new identities for unions, intersections, set difference, etc.;
  5548 
  5549 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5550 called split_if, split_split, split_sum_case and split_nat_case (to go
  5551 with add/delsplits);
  5552 
  5553 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5554 (?x::unit) = (); this is made part of the default simpset, which COULD
  5555 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5556 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5557 unit_abs_eta_conv is added in order to counter the effect of
  5558 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5559 %u.f();
  5560 
  5561 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5562 makes more sense);
  5563 
  5564 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5565   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5566   disjointness reasoning but breaking a few old proofs.
  5567 
  5568 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5569 to 'converse' from 'inverse' (for compatibility with ZF and some
  5570 literature);
  5571 
  5572 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5573 the well-founded relation;
  5574 
  5575 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5576     Compl A.  The "Compl" syntax remains available as input syntax for this
  5577     release ONLY.
  5578 
  5579 * HOL/Update: new theory of function updates:
  5580     f(a:=b) == %x. if x=a then b else f x
  5581 may also be iterated as in f(a:=b,c:=d,...);
  5582 
  5583 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5584 
  5585 * HOL/List:
  5586   - new function list_update written xs[i:=v] that updates the i-th
  5587     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5588   - new function `upt' written [i..j(] which generates the list
  5589     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5590     bound write [i..j], which is a shorthand for [i..j+1(].
  5591   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5592 
  5593 * HOL/Arith:
  5594   - removed 'pred' (predecessor) function;
  5595   - generalized some theorems about n-1;
  5596   - many new laws about "div" and "mod";
  5597   - new laws about greatest common divisors (see theory ex/Primes);
  5598 
  5599 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5600 instead of "inverse";
  5601 
  5602 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5603   of the multiset ordering;
  5604 
  5605 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5606   (not included by default);
  5607 
  5608 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5609 
  5610 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5611   programs, i.e. different program variables may have different types.
  5612 
  5613 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5614   [previously, this check worked only if the rewrite rule was unconditional]
  5615   Now rew can involve either definitions or equalities (either == or =).
  5616 
  5617 
  5618 *** ZF ***
  5619 
  5620 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5621   only the theorems proved on ZF.ML;
  5622 
  5623 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5624   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5625   disjointness reasoning but breaking a few old proofs.
  5626 
  5627 * ZF/Update: new theory of function updates
  5628     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5629   may also be iterated as in f(a:=b,c:=d,...);
  5630 
  5631 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5632 
  5633 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5634   [previously, this check worked only if the rewrite rule was unconditional]
  5635   Now rew can involve either definitions or equalities (either == or =).
  5636 
  5637 * case_tac provided for compatibility with HOL
  5638     (like the old excluded_middle_tac, but with subgoals swapped)
  5639 
  5640 
  5641 *** Internal programming interfaces ***
  5642 
  5643 * Pure: several new basic modules made available for general use, see
  5644 also src/Pure/README;
  5645 
  5646 * improved the theory data mechanism to support encapsulation (data
  5647 kind name replaced by private Object.kind, acting as authorization
  5648 key); new type-safe user interface via functor TheoryDataFun; generic
  5649 print_data function becomes basically useless;
  5650 
  5651 * removed global_names compatibility flag -- all theory declarations
  5652 are qualified by default;
  5653 
  5654 * module Pure/Syntax now offers quote / antiquote translation
  5655 functions (useful for Hoare logic etc. with implicit dependencies);
  5656 see HOL/ex/Antiquote for an example use;
  5657 
  5658 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5659 cterm -> thm;
  5660 
  5661 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5662 subgoal;
  5663 
  5664 * Display.print_goals function moved to Locale.print_goals;
  5665 
  5666 * standard print function for goals supports current_goals_markers
  5667 variable for marking begin of proof, end of proof, start of goal; the
  5668 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5669 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5670 for example;
  5671 
  5672 
  5673 
  5674 New in Isabelle98 (January 1998)
  5675 --------------------------------
  5676 
  5677 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5678 
  5679 * changed lexical syntax of terms / types: dots made part of long
  5680 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5681 
  5682 * simpset (and claset) reference variable replaced by functions
  5683 simpset / simpset_ref;
  5684 
  5685 * no longer supports theory aliases (via merge) and non-trivial
  5686 implicit merge of thms' signatures;
  5687 
  5688 * most internal names of constants changed due to qualified names;
  5689 
  5690 * changed Pure/Sequence interface (see Pure/seq.ML);
  5691 
  5692 
  5693 *** General Changes ***
  5694 
  5695 * hierachically structured name spaces (for consts, types, axms, thms
  5696 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5697 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5698 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5699 long_names for fully qualified output names; NOTE: ML programs
  5700 (special tactics, packages etc.) referring to internal names may have
  5701 to be adapted to cope with fully qualified names; in case of severe
  5702 backward campatibility problems try setting 'global_names' at compile
  5703 time to have enrything declared within a flat name space; one may also
  5704 fine tune name declarations in theories via the 'global' and 'local'
  5705 section;
  5706 
  5707 * reimplemented the implicit simpset and claset using the new anytype
  5708 data filed in signatures; references simpset:simpset ref etc. are
  5709 replaced by functions simpset:unit->simpset and
  5710 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5711 to patch your ML files accordingly;
  5712 
  5713 * HTML output now includes theory graph data for display with Java
  5714 applet or isatool browser; data generated automatically via isatool
  5715 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5716 
  5717 * defs may now be conditional; improved rewrite_goals_tac to handle
  5718 conditional equations;
  5719 
  5720 * defs now admits additional type arguments, using TYPE('a) syntax;
  5721 
  5722 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5723 creates a new theory node; implicit merge of thms' signatures is
  5724 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5725 transfer:theory->thm->thm in (rare) cases;
  5726 
  5727 * improved handling of draft signatures / theories; draft thms (and
  5728 ctyps, cterms) are automatically promoted to real ones;
  5729 
  5730 * slightly changed interfaces for oracles: admit many per theory, named
  5731 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5732 
  5733 * print_goals: optional output of const types (set show_consts and
  5734 show_types);
  5735 
  5736 * improved output of warnings (###) and errors (***);
  5737 
  5738 * subgoal_tac displays a warning if the new subgoal has type variables;
  5739 
  5740 * removed old README and Makefiles;
  5741 
  5742 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5743 
  5744 * removed obsolete init_pps and init_database;
  5745 
  5746 * deleted the obsolete tactical STATE, which was declared by
  5747     fun STATE tacfun st = tacfun st st;
  5748 
  5749 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5750 (which abbreviates $HOME);
  5751 
  5752 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5753 use isatool fixseq to adapt your ML programs (this works for fully
  5754 qualified references to the Sequence structure only!);
  5755 
  5756 * use_thy no longer requires writable current directory; it always
  5757 reloads .ML *and* .thy file, if either one is out of date;
  5758 
  5759 
  5760 *** Classical Reasoner ***
  5761 
  5762 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5763 tactics that use classical reasoning to simplify a subgoal without
  5764 splitting it into several subgoals;
  5765 
  5766 * Safe_tac: like safe_tac but uses the default claset;
  5767 
  5768 
  5769 *** Simplifier ***
  5770 
  5771 * added simplification meta rules:
  5772     (asm_)(full_)simplify: simpset -> thm -> thm;
  5773 
  5774 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5775 logics (again);
  5776 
  5777 * added prems argument to simplification procedures;
  5778 
  5779 * HOL, FOL, ZF: added infix function `addsplits':
  5780   instead of `<simpset> setloop (split_tac <thms>)'
  5781   you can simply write `<simpset> addsplits <thms>'
  5782 
  5783 
  5784 *** Syntax ***
  5785 
  5786 * TYPE('a) syntax for type reflection terms;
  5787 
  5788 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5789 
  5790 * pretty printer: changed order of mixfix annotation preference (again!);
  5791 
  5792 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5793 
  5794 
  5795 *** HOL ***
  5796 
  5797 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5798   with `addloop' of the simplifier to faciliate case splitting in premises.
  5799 
  5800 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5801 
  5802 * HOL/Auth: new protocol proofs including some for the Internet
  5803   protocol TLS;
  5804 
  5805 * HOL/Map: new theory of `maps' a la VDM;
  5806 
  5807 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5808 cancelling out common nat summands from =, <, <= (in)equalities, or
  5809 differences; simplification procedures nat_cancel_factor for
  5810 cancelling common factor from =, <, <= (in)equalities over natural
  5811 sums; nat_cancel contains both kinds of procedures, it is installed by
  5812 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5813 
  5814 * HOL/simplifier: terms of the form
  5815   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5816   are rewritten to
  5817   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5818   and those of the form
  5819   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5820   are rewritten to
  5821   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5822 
  5823 * HOL/datatype
  5824   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5825 
  5826   P(t_case f1 ... fn x) =
  5827      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5828         ...
  5829        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5830      )
  5831 
  5832   and a theorem `split_t_case_asm' of the form
  5833 
  5834   P(t_case f1 ... fn x) =
  5835     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5836         ...
  5837        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5838      )
  5839   which can be added to a simpset via `addsplits'. The existing theorems
  5840   expand_list_case and expand_option_case have been renamed to
  5841   split_list_case and split_option_case.
  5842 
  5843 * HOL/Arithmetic:
  5844   - `pred n' is automatically converted to `n-1'.
  5845     Users are strongly encouraged not to use `pred' any longer,
  5846     because it will disappear altogether at some point.
  5847   - Users are strongly encouraged to write "0 < n" rather than
  5848     "n ~= 0". Theorems and proof tools have been modified towards this
  5849     `standard'.
  5850 
  5851 * HOL/Lists:
  5852   the function "set_of_list" has been renamed "set" (and its theorems too);
  5853   the function "nth" now takes its arguments in the reverse order and
  5854   has acquired the infix notation "!" as in "xs!n".
  5855 
  5856 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5857 
  5858 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5859   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5860 
  5861 * HOL/record: extensible records with schematic structural subtyping
  5862 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5863 still lacks various theorems and concrete record syntax;
  5864 
  5865 
  5866 *** HOLCF ***
  5867 
  5868 * removed "axioms" and "generated by" sections;
  5869 
  5870 * replaced "ops" section by extended "consts" section, which is capable of
  5871   handling the continuous function space "->" directly;
  5872 
  5873 * domain package:
  5874   . proves theorems immediately and stores them in the theory,
  5875   . creates hierachical name space,
  5876   . now uses normal mixfix annotations (instead of cinfix...),
  5877   . minor changes to some names and values (for consistency),
  5878   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5879   . separator between mutual domain defs: changed "," to "and",
  5880   . improved handling of sort constraints;  now they have to
  5881     appear on the left-hand side of the equations only;
  5882 
  5883 * fixed LAM <x,y,zs>.b syntax;
  5884 
  5885 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5886 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5887 
  5888 
  5889 *** FOL and ZF ***
  5890 
  5891 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5892   with `addloop' of the simplifier to faciliate case splitting in premises.
  5893 
  5894 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5895 in HOL, they strip ALL and --> from proved theorems;
  5896 
  5897 
  5898 
  5899 New in Isabelle94-8 (May 1997)
  5900 ------------------------------
  5901 
  5902 *** General Changes ***
  5903 
  5904 * new utilities to build / run / maintain Isabelle etc. (in parts
  5905 still somewhat experimental); old Makefiles etc. still functional;
  5906 
  5907 * new 'Isabelle System Manual';
  5908 
  5909 * INSTALL text, together with ./configure and ./build scripts;
  5910 
  5911 * reimplemented type inference for greater efficiency, better error
  5912 messages and clean internal interface;
  5913 
  5914 * prlim command for dealing with lots of subgoals (an easier way of
  5915 setting goals_limit);
  5916 
  5917 
  5918 *** Syntax ***
  5919 
  5920 * supports alternative (named) syntax tables (parser and pretty
  5921 printer); internal interface is provided by add_modesyntax(_i);
  5922 
  5923 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5924 be used in conjunction with the Isabelle symbol font; uses the
  5925 "symbols" syntax table;
  5926 
  5927 * added token_translation interface (may translate name tokens in
  5928 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5929 the current print_mode); IMPORTANT: user print translation functions
  5930 are responsible for marking newly introduced bounds
  5931 (Syntax.mark_boundT);
  5932 
  5933 * token translations for modes "xterm" and "xterm_color" that display
  5934 names in bold, underline etc. or colors (which requires a color
  5935 version of xterm);
  5936 
  5937 * infixes may now be declared with names independent of their syntax;
  5938 
  5939 * added typed_print_translation (like print_translation, but may
  5940 access type of constant);
  5941 
  5942 
  5943 *** Classical Reasoner ***
  5944 
  5945 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5946 some limitations.  Blast_tac...
  5947   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5948   + ignores elimination rules that don't have the correct format
  5949         (the conclusion MUST be a formula variable)
  5950   + ignores types, which can make HOL proofs fail
  5951   + rules must not require higher-order unification, e.g. apply_type in ZF
  5952     [message "Function Var's argument not a bound variable" relates to this]
  5953   + its proof strategy is more general but can actually be slower
  5954 
  5955 * substitution with equality assumptions no longer permutes other
  5956 assumptions;
  5957 
  5958 * minor changes in semantics of addafter (now called addaltern); renamed
  5959 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5960 (and access functions for it);
  5961 
  5962 * improved combination of classical reasoner and simplifier:
  5963   + functions for handling clasimpsets
  5964   + improvement of addss: now the simplifier is called _after_ the
  5965     safe steps.
  5966   + safe variant of addss called addSss: uses safe simplifications
  5967     _during_ the safe steps. It is more complete as it allows multiple
  5968     instantiations of unknowns (e.g. with slow_tac).
  5969 
  5970 *** Simplifier ***
  5971 
  5972 * added interface for simplification procedures (functions that
  5973 produce *proven* rewrite rules on the fly, depending on current
  5974 redex);
  5975 
  5976 * ordering on terms as parameter (used for ordered rewriting);
  5977 
  5978 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5979 
  5980 * the solver is now split into a safe and an unsafe part.
  5981 This should be invisible for the normal user, except that the
  5982 functions setsolver and addsolver have been renamed to setSolver and
  5983 addSolver; added safe_asm_full_simp_tac;
  5984 
  5985 
  5986 *** HOL ***
  5987 
  5988 * a generic induction tactic `induct_tac' which works for all datatypes and
  5989 also for type `nat';
  5990 
  5991 * a generic case distinction tactic `exhaust_tac' which works for all
  5992 datatypes and also for type `nat';
  5993 
  5994 * each datatype comes with a function `size';
  5995 
  5996 * patterns in case expressions allow tuple patterns as arguments to
  5997 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5998 
  5999 * primrec now also works with type nat;
  6000 
  6001 * recdef: a new declaration form, allows general recursive functions to be
  6002 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6003 
  6004 * the constant for negation has been renamed from "not" to "Not" to
  6005 harmonize with FOL, ZF, LK, etc.;
  6006 
  6007 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6008 infinite lists;
  6009 
  6010 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6011 
  6012 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6013 problems in commutative rings, using axiomatic type classes for + and *;
  6014 
  6015 * more examples in HOL/MiniML and HOL/Auth;
  6016 
  6017 * more default rewrite rules for quantifiers, union/intersection;
  6018 
  6019 * a new constant `arbitrary == @x.False';
  6020 
  6021 * HOLCF/IOA replaces old HOL/IOA;
  6022 
  6023 * HOLCF changes: derived all rules and arities
  6024   + axiomatic type classes instead of classes
  6025   + typedef instead of faking type definitions
  6026   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6027   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6028   + eliminated the types void, one, tr
  6029   + use unit lift and bool lift (with translations) instead of one and tr
  6030   + eliminated blift from Lift3.thy (use Def instead of blift)
  6031   all eliminated rules are derived as theorems --> no visible changes ;
  6032 
  6033 
  6034 *** ZF ***
  6035 
  6036 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6037 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6038 as ZF_cs addSIs [equalityI];
  6039 
  6040 
  6041 
  6042 New in Isabelle94-7 (November 96)
  6043 ---------------------------------
  6044 
  6045 * allowing negative levels (as offsets) in prlev and choplev;
  6046 
  6047 * super-linear speedup for large simplifications;
  6048 
  6049 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6050 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6051 FAIL); can suppress it using the command Delsimps (ex_simps @
  6052 all_simps); De Morgan laws are also now included, by default;
  6053 
  6054 * improved printing of ==>  :  ~:
  6055 
  6056 * new object-logic "Sequents" adds linear logic, while replacing LK
  6057 and Modal (thanks to Sara Kalvala);
  6058 
  6059 * HOL/Auth: correctness proofs for authentication protocols;
  6060 
  6061 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6062 examples on HOL/Auth);
  6063 
  6064 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6065 the rewriter and classical reasoner simultaneously;
  6066 
  6067 * function uresult no longer returns theorems in "standard" format;
  6068 regain previous version by: val uresult = standard o uresult;
  6069 
  6070 
  6071 
  6072 New in Isabelle94-6
  6073 -------------------
  6074 
  6075 * oracles -- these establish an interface between Isabelle and trusted
  6076 external reasoners, which may deliver results as theorems;
  6077 
  6078 * proof objects (in particular record all uses of oracles);
  6079 
  6080 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6081 
  6082 * "constdefs" section in theory files;
  6083 
  6084 * "primrec" section (HOL) no longer requires names;
  6085 
  6086 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6087 
  6088 
  6089 
  6090 New in Isabelle94-5
  6091 -------------------
  6092 
  6093 * reduced space requirements;
  6094 
  6095 * automatic HTML generation from theories;
  6096 
  6097 * theory files no longer require "..." (quotes) around most types;
  6098 
  6099 * new examples, including two proofs of the Church-Rosser theorem;
  6100 
  6101 * non-curried (1994) version of HOL is no longer distributed;
  6102 
  6103 
  6104 
  6105 New in Isabelle94-4
  6106 -------------------
  6107 
  6108 * greatly reduced space requirements;
  6109 
  6110 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6111 
  6112 * searchable theorem database (see the section "Retrieving theorems" on
  6113 page 8 of the Reference Manual);
  6114 
  6115 * new examples, including Grabczewski's monumental case study of the
  6116 Axiom of Choice;
  6117 
  6118 * The previous version of HOL renamed to Old_HOL;
  6119 
  6120 * The new version of HOL (previously called CHOL) uses a curried syntax
  6121 for functions.  Application looks like f a b instead of f(a,b);
  6122 
  6123 * Mutually recursive inductive definitions finally work in HOL;
  6124 
  6125 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6126 translates to the operator "split";
  6127 
  6128 
  6129 
  6130 New in Isabelle94-3
  6131 -------------------
  6132 
  6133 * new infix operator, addss, allowing the classical reasoner to
  6134 perform simplification at each step of its search.  Example:
  6135         fast_tac (cs addss ss)
  6136 
  6137 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6138 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6139 look like (a,b) instead of <a,b>;
  6140 
  6141 * PLEASE NOTE: CHOL will eventually replace HOL!
  6142 
  6143 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6144 It translates to the operator "split".  A new theory of integers is available;
  6145 
  6146 * In ZF, integer numerals now denote two's-complement binary integers.
  6147 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6148 
  6149 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6150 of the Axiom of Choice;
  6151 
  6152 
  6153 
  6154 New in Isabelle94-2
  6155 -------------------
  6156 
  6157 * Significantly faster resolution;
  6158 
  6159 * the different sections in a .thy file can now be mixed and repeated
  6160 freely;
  6161 
  6162 * Database of theorems for FOL, HOL and ZF.  New
  6163 commands including qed, qed_goal and bind_thm store theorems in the database.
  6164 
  6165 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6166 a given theory (thms_of), or find out what theory a theorem was proved in
  6167 (theory_of_thm);
  6168 
  6169 * Bugs fixed in the inductive definition and datatype packages;
  6170 
  6171 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6172 and HOL_dup_cs obsolete;
  6173 
  6174 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6175 have been removed;
  6176 
  6177 * Simpler definition of function space in ZF;
  6178 
  6179 * new results about cardinal and ordinal arithmetic in ZF;
  6180 
  6181 * 'subtype' facility in HOL for introducing new types as subsets of existing
  6182 types;
  6183 
  6184 :mode=text:wrap=hard:maxLineLen=72: