NEWS
author wenzelm
Mon Mar 09 22:43:25 2009 +0100 (2009-03-09)
changeset 30399 a4772a650b4e
parent 30395 f3103bd2b167
child 30415 9501af91c4a3
permissions -rw-r--r--
tuned;
     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 
   202 *** Document preparation ***
   203 
   204 * Antiquotation @{lemma} now imitates a regular terminal proof,
   205 demanding keyword 'by' and supporting the full method expression
   206 syntax just like the Isar command 'by'.
   207 
   208 
   209 *** HOL ***
   210 
   211 * Theory Library/Diagonalize.thy provides constructive version of
   212 Cantor's first diagonalization argument.
   213 
   214 * New predicate "strict_mono" classifies strict functions on partial orders.
   215 With strict functions on linear orders, reasoning about (in)equalities is
   216 facilitated by theorems "strict_mono_eq", "strict_mono_less_eq" and "strict_mono_less".
   217 
   218 * Some set operations are now proper qualified constants with authentic syntax.
   219 INCOMPATIBILITY:
   220 
   221     op Int ~>   Set.Int
   222     op Un ~>    Set.Un
   223     INTER ~>    Set.INTER
   224     UNION ~>    Set.UNION
   225     Inter ~>    Set.Inter
   226     Union ~>    Set.Union
   227     {} ~>       Set.empty
   228     UNIV ~>     Set.UNIV
   229 
   230 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in theory
   231 Set.
   232 
   233 * Auxiliary class "itself" has disappeared -- classes without any parameter
   234 are treated as expected by the 'class' command.
   235 
   236 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   237 
   238 * Common decision procedures (Cooper, MIR, Ferrack, Approximation, Dense_Linear_Order)
   239 now in directory HOL/Decision_Procs.
   240 
   241 * Theory HOL/Decisioin_Procs/Approximation.thy provides the new proof method
   242 "approximation".  It proves formulas on real values by using interval arithmetic.
   243 In the formulas are also the transcendental functions sin, cos, tan, atan, ln,
   244 exp and the constant pi are allowed.  For examples see HOL/ex/ApproximationEx.thy.
   245 
   246 * Theory "Reflection" now resides in HOL/Library.
   247 
   248 * Entry point to Word library now simply named "Word".  INCOMPATIBILITY.
   249 
   250 * Made source layout more coherent with logical distribution
   251 structure:
   252 
   253     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   254     src/HOL/Library/Code_Message.thy ~> src/HOL/
   255     src/HOL/Library/GCD.thy ~> src/HOL/
   256     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   257     src/HOL/Library/Parity.thy ~> src/HOL/
   258     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   259     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   260     src/HOL/Real/Lubs.thy ~> src/HOL/
   261     src/HOL/Real/PReal.thy ~> src/HOL/
   262     src/HOL/Real/Rational.thy ~> src/HOL/
   263     src/HOL/Real/RComplete.thy ~> src/HOL/
   264     src/HOL/Real/RealDef.thy ~> src/HOL/
   265     src/HOL/Real/RealPow.thy ~> src/HOL/
   266     src/HOL/Real/Real.thy ~> src/HOL/
   267     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   268     src/HOL/Complex/Complex.thy ~> src/HOL/
   269     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   270     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   271     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   272     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   273     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   274     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   275     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   276     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   277     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   278     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   279     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   280     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   281     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   282     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   283     src/HOL/Real/Float ~> src/HOL/Library/
   284     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   285     src/HOL/Real/RealVector.thy ~> src/HOL/
   286 
   287     src/HOL/arith_data.ML ~> src/HOL/Tools
   288     src/HOL/hologic.ML ~> src/HOL/Tools
   289     src/HOL/simpdata.ML ~> src/HOL/Tools
   290     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   291     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   292     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   293     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   294     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   295     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   296     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   297 
   298     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   299     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   300     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   301     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   302     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   303     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   304 
   305 * If methods "eval" and "evaluation" encounter a structured proof state
   306 with !!/==>, only the conclusion is evaluated to True (if possible),
   307 avoiding strange error messages.
   308 
   309 * Simplifier: simproc for let expressions now unfolds if bound variable
   310 occurs at most once in let expression body.  INCOMPATIBILITY.
   311 
   312 * New classes "top" and "bot" with corresponding operations "top" and "bot"
   313 in theory Orderings;  instantiation of class "complete_lattice" requires
   314 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   315 
   316 * Changed definition lemma "less_fun_def" in order to provide an instance
   317 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   318 
   319 * Unified theorem tables for both code code generators.  Thus
   320 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   321 
   322 * Constants "undefined" and "default" replace "arbitrary".  Usually
   323 "undefined" is the right choice to replace "arbitrary", though logically
   324 there is no difference.  INCOMPATIBILITY.
   325 
   326 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   327 Posix processes.  Avoids potentially expensive forking of the ML
   328 process.  New thread-based implementation also works on non-Unix
   329 platforms (Cygwin).  Provers are no longer hardwired, but defined
   330 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   331 commands are covered in the isar-ref manual.
   332 
   333 * Wrapper scripts for remote SystemOnTPTP service allows to use
   334 sledgehammer without local ATP installation (Vampire etc.).  See also
   335 ISABELLE_HOME/contrib/SystemOnTPTP and the VAMPIRE_HOME setting
   336 variable.  Other provers may be included via suitable ML wrappers, see
   337 also src/HOL/ATP_Linkup.thy.
   338 
   339 * Normalization by evaluation now allows non-leftlinear equations.
   340 Declare with attribute [code nbe].
   341 
   342 * Command "value" now integrates different evaluation
   343 mechanisms.  The result of the first successful evaluation mechanism
   344 is printed.  In square brackets a particular named evaluation
   345 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   346 further src/HOL/ex/Eval_Examples.thy.
   347 
   348 * New method "sizechange" to automate termination proofs using (a
   349 modification of) the size-change principle. Requires SAT solver. See
   350 src/HOL/ex/Termination.thy for examples.
   351 
   352 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   353 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   354 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   355 
   356 * HOL/Orderings: added class "preorder" as superclass of "order".
   357 INCOMPATIBILITY: Instantiation proofs for order, linorder
   358 etc. slightly changed.  Some theorems named order_class.* now named
   359 preorder_class.*.
   360 
   361 * HOL/Relation:
   362 Renamed "refl" to "refl_on", "reflexive" to "refl, "diag" to "Id_on".
   363 
   364 * HOL/Finite_Set: added a new fold combinator of type
   365   ('a => 'b => 'b) => 'b => 'a set => 'b
   366 Occasionally this is more convenient than the old fold combinator which is
   367 now defined in terms of the new one and renamed to fold_image.
   368 
   369 * HOL/Ring_and_Field and HOL/OrderedGroup: The lemmas "group_simps" and
   370 "ring_simps" have been replaced by "algebra_simps" (which can be extended with
   371 further lemmas!). At the moment both still exist but the former will disappear
   372 at some point.
   373 
   374 * HOL/Power: Lemma power_Suc is now declared as a simp rule in class
   375 recpower.  Type-specific simp rules for various recpower types have
   376 been removed.  INCOMPATIBILITY.  Rename old lemmas as follows:
   377 
   378 rat_power_0    -> power_0
   379 rat_power_Suc  -> power_Suc
   380 realpow_0      -> power_0
   381 realpow_Suc    -> power_Suc
   382 complexpow_0   -> power_0
   383 complexpow_Suc -> power_Suc
   384 power_poly_0   -> power_0
   385 power_poly_Suc -> power_Suc
   386 
   387 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   388 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   389 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   390 of lemmas from Divides has been generalized from nat to class
   391 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   392 renames resulting from duplicate elimination:
   393 
   394     dvd_def_mod ~>          dvd_eq_mod_eq_0
   395     zero_dvd_iff ~>         dvd_0_left_iff
   396     dvd_0 ~>                dvd_0_right
   397     DIVISION_BY_ZERO_DIV ~> div_by_0
   398     DIVISION_BY_ZERO_MOD ~> mod_by_0
   399     mult_div ~>             div_mult_self2_is_id
   400     mult_mod ~>             mod_mult_self2_is_0
   401 
   402 * HOL/IntDiv: removed many lemmas that are instances of class-based
   403 generalizations (from Divides and Ring_and_Field).
   404 INCOMPATIBILITY. Rename old lemmas as follows:
   405 
   406 dvd_diff               -> nat_dvd_diff
   407 dvd_zminus_iff         -> dvd_minus_iff
   408 mod_add1_eq            -> mod_add_eq
   409 mod_mult1_eq           -> mod_mult_right_eq
   410 mod_mult1_eq'          -> mod_mult_left_eq
   411 mod_mult_distrib_mod   -> mod_mult_eq
   412 nat_mod_add_left_eq    -> mod_add_left_eq
   413 nat_mod_add_right_eq   -> mod_add_right_eq
   414 nat_mod_div_trivial    -> mod_div_trivial
   415 nat_mod_mod_trivial    -> mod_mod_trivial
   416 zdiv_zadd_self1        -> div_add_self1
   417 zdiv_zadd_self2        -> div_add_self2
   418 zdiv_zmult_self1       -> div_mult_self2_is_id
   419 zdiv_zmult_self2       -> div_mult_self1_is_id
   420 zdvd_triv_left         -> dvd_triv_left
   421 zdvd_triv_right        -> dvd_triv_right
   422 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   423 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   424 zmod_zadd_left_eq      -> mod_add_left_eq
   425 zmod_zadd_right_eq     -> mod_add_right_eq
   426 zmod_zadd_self1        -> mod_add_self1
   427 zmod_zadd_self2        -> mod_add_self2
   428 zmod_zadd1_eq          -> mod_add_eq
   429 zmod_zdiff1_eq         -> mod_diff_eq
   430 zmod_zdvd_zmod         -> mod_mod_cancel
   431 zmod_zmod_cancel       -> mod_mod_cancel
   432 zmod_zmult_self1       -> mod_mult_self2_is_0
   433 zmod_zmult_self2       -> mod_mult_self1_is_0
   434 zmod_1                 -> mod_by_1
   435 zdiv_1                 -> div_by_1
   436 zdvd_abs1              -> abs_dvd_iff
   437 zdvd_abs2              -> dvd_abs_iff
   438 zdvd_refl              -> dvd_refl
   439 zdvd_trans             -> dvd_trans
   440 zdvd_zadd              -> dvd_add
   441 zdvd_zdiff             -> dvd_diff
   442 zdvd_zminus_iff        -> dvd_minus_iff
   443 zdvd_zminus2_iff       -> minus_dvd_iff
   444 zdvd_zmultD            -> dvd_mult_right
   445 zdvd_zmultD2           -> dvd_mult_left
   446 zdvd_zmult_mono        -> mult_dvd_mono
   447 zdvd_0_right           -> dvd_0_right
   448 zdvd_0_left            -> dvd_0_left_iff
   449 zdvd_1_left            -> one_dvd
   450 zminus_dvd_iff         -> minus_dvd_iff
   451 
   452 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   453 zlcm (for int); carried together from various gcd/lcm developements in
   454 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   455 corresponding theorems renamed accordingly.  INCOMPATIBILITY.  To
   456 recover tupled syntax, use syntax declarations like:
   457 
   458     hide (open) const gcd
   459     abbreviation gcd where
   460       "gcd == (%(a, b). GCD.gcd a b)"
   461     notation (output)
   462       GCD.gcd ("gcd '(_, _')")
   463 
   464 (analogously for lcm, zgcd, zlcm).
   465 
   466 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   467 
   468 * The real numbers offer decimal input syntax: 12.34 is translated into
   469   1234/10^2. This translation is not reversed upon output.
   470 
   471 * New ML antiquotation @{code}: takes constant as argument, generates
   472 corresponding code in background and inserts name of the corresponding
   473 resulting ML value/function/datatype constructor binding in place.
   474 All occurrences of @{code} with a single ML block are generated
   475 simultaneously.  Provides a generic and safe interface for
   476 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   477 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   478 application.  In future you ought refrain from ad-hoc compiling
   479 generated SML code on the ML toplevel.  Note that (for technical
   480 reasons) @{code} cannot refer to constants for which user-defined
   481 serializations are set.  Refer to the corresponding ML counterpart
   482 directly in that cases.
   483 
   484 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   485 Complex_Main.thy remain as they are.
   486 
   487 * New image HOL-Plain provides a minimal HOL with the most important
   488 tools available (inductive, datatype, primrec, ...).  By convention
   489 the corresponding theory Plain should be ancestor of every further
   490 (library) theory.  Some library theories now have ancestor Plain
   491 (instead of Main), thus theory Main occasionally has to be imported
   492 explicitly.
   493 
   494 * The metis method now fails in the usual manner, rather than raising
   495 an exception, if it determines that it cannot prove the theorem.
   496 
   497 * The metis method no longer fails because the theorem is too trivial
   498 (contains the empty clause).
   499 
   500 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   501 as the structured Isar versions "cases" and "induct", cf. the
   502 corresponding "cases" and "induct" attributes.  Mutual induction rules
   503 are now presented as a list of individual projections
   504 (e.g. foo_bar.inducts for types foo and bar); the old format with
   505 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   506 rare situations a different rule is selected --- notably nested tuple
   507 elimination instead of former prod.exhaust: use explicit (case_tac t
   508 rule: prod.exhaust) here.
   509 
   510 * Attributes "cases", "induct", "coinduct" support "del" option.
   511 
   512 * Removed fact "case_split_thm", which duplicates "case_split".
   513 
   514 * Command 'rep_datatype': instead of theorem names the command now
   515 takes a list of terms denoting the constructors of the type to be
   516 represented as datatype.  The characteristic theorems have to be
   517 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   518 have disappeared in favour of existing ones:
   519 
   520     unit_induct                 ~> unit.induct
   521     prod_induct                 ~> prod.induct
   522     sum_induct                  ~> sum.induct
   523     Suc_Suc_eq                  ~> nat.inject
   524     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   525 
   526 * The option datatype has been moved to a new theory HOL/Option.thy.
   527 Renamed option_map to Option.map, and o2s to Option.set.
   528 
   529 * Library/Nat_Infinity: added addition, numeral syntax and more
   530 instantiations for algebraic structures.  Removed some duplicate
   531 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   532 
   533 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   534 menu.
   535 
   536 
   537 *** HOL-Algebra ***
   538 
   539 * New locales for orders and lattices where the equivalence relation
   540 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   541 locales use a record structure with field eq for the equivalence.
   542 
   543 * New theory of factorial domains.
   544 
   545 * Units_l_inv and Units_r_inv are now simprules by default.
   546 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   547 and/or r_inv will now also require deletion of these lemmas.
   548 
   549 * Renamed the following theorems.  INCOMPATIBILITY.
   550 UpperD ~> Upper_memD
   551 LowerD ~> Lower_memD
   552 least_carrier ~> least_closed
   553 greatest_carrier ~> greatest_closed
   554 greatest_Lower_above ~> greatest_Lower_below
   555 one_zero ~> carrier_one_zero
   556 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   557 
   558 
   559 *** HOL-NSA ***
   560 
   561 * Created new image HOL-NSA, containing theories of nonstandard
   562 analysis which were previously part of HOL-Complex.  Entry point
   563 Hyperreal.thy remains valid, but theories formerly using
   564 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   565 
   566 
   567 *** ZF ***
   568 
   569 * Proof of Zorn's Lemma for partial orders.
   570 
   571 
   572 *** HOLCF ***
   573 
   574 * Reimplemented the simplification procedure for proving continuity
   575 subgoals.  The new simproc is extensible; users can declare additional
   576 continuity introduction rules with the attribute [cont2cont].
   577 
   578 * The continuity simproc now uses a different introduction rule for
   579 solving continuity subgoals on terms with lambda abstractions.  In
   580 some rare cases the new simproc may fail to solve subgoals that the
   581 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   582 Potential INCOMPATIBILITY.
   583 
   584 * The syntax of the fixrec package has changed.  The specification
   585 syntax now conforms in style to definition, primrec, function, etc.
   586 See HOLCF/ex/Fixrec_ex.thy for examples.  INCOMPATIBILITY.
   587 
   588 
   589 *** ML ***
   590 
   591 * High-level support for concurrent ML programming, see
   592 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   593 particularly convenient to organize independent functional
   594 computations.  The concept of "synchronized variables" provides a
   595 higher-order interface for components with shared state, avoiding the
   596 delicate details of mutexes and condition variables.  [Poly/ML 5.2.1
   597 or later]
   598 
   599 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   600 to 'a -> thm, while results are always tagged with an authentic oracle
   601 name.  The Isar command 'oracle' is now polymorphic, no argument type
   602 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   603 accordingly.  Note that extra performance may be gained by producing
   604 the cterm carefully, avoiding slow Thm.cterm_of.
   605 
   606 * ML bindings produced via Isar commands are stored within the Isar
   607 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   608 become thread-safe and work with undo as expected (concerning
   609 top-level bindings, not side-effects on global references).
   610 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   611 compiler at runtime; really global bindings need to be given outside a
   612 theory. [Poly/ML 5.2 or later]
   613 
   614 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   615 context. Top-level ML bindings are stored within the proof context in
   616 a purely sequential fashion, disregarding the nested proof structure.
   617 ML bindings introduced by 'ML_prf' are discarded at the end of the
   618 proof.  [Poly/ML 5.2 or later]
   619 
   620 * Generic Toplevel.add_hook interface allows to analyze the result of
   621 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   622 for theorem dependency output of transactions resulting in a new
   623 theory state.
   624 
   625 * More systematic treatment of long names, abstract name bindings, and
   626 name space operations.  Basic operations on qualified names have been
   627 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   628 Long_Name.append.  Old type bstring has been mostly replaced by
   629 abstract type binding (see structure Binding), which supports precise
   630 qualification (by packages and local theory targets), as well as
   631 proper tracking of source positions.  INCOMPATIBILITY, need to wrap
   632 old bstring values into Binding.name, or better pass through abstract
   633 bindings everywhere.  See further src/Pure/General/long_name.ML,
   634 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   635 
   636 * Simplified interface for defining document antiquotations via
   637 ThyOutput.antiquotation, ThyOutput.output, and optionally
   638 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   639 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   640 examples.
   641 
   642 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   643 LocalTheory.note etc.) now refer to the *full* internal name, not the
   644 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   645 
   646 * Rules and tactics that read instantiations (read_instantiate,
   647 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   648 context, which is required for parsing and type-checking.  Moreover,
   649 the variables are specified as plain indexnames, not string encodings
   650 thereof.  INCOMPATIBILITY.
   651 
   652 * Disposed old type and term read functions (Sign.read_def_typ,
   653 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   654 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   655 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   656 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   657 resort for legacy applications.
   658 
   659 * Antiquotations: block-structured compilation context indicated by
   660 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   661 
   662   @{let ?pat = term}                      - term abbreviation (HO matching)
   663   @{note name = fact}                     - fact abbreviation
   664   @{thm fact}                             - singleton fact (with attributes)
   665   @{thms fact}                            - general fact (with attributes)
   666   @{lemma prop by method}                 - singleton goal
   667   @{lemma prop by meth1 meth2}            - singleton goal
   668   @{lemma prop1 ... propN by method}      - general goal
   669   @{lemma prop1 ... propN by meth1 meth2} - general goal
   670   @{lemma (open) ...}                     - open derivation
   671 
   672 
   673 *** System ***
   674 
   675 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   676 Poly/ML 5.2.1 or later.
   677 
   678 * The Isabelle "emacs" tool provides a specific interface to invoke
   679 Proof General / Emacs, with more explicit failure if that is not
   680 installed (the old isabelle-interface script silently falls back on
   681 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   682 installation location of the Proof General distribution.
   683 
   684 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   685 the Isabelle process into a JVM/Scala application.  See
   686 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   687 process wrapper has been discontinued.)
   688 
   689 * Status messages (with exact source position information) are
   690 emitted, if proper markup print mode is enabled.  This allows
   691 user-interface components to provide detailed feedback on internal
   692 prover operations.
   693 
   694 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   695 
   696 
   697 
   698 New in Isabelle2008 (June 2008)
   699 -------------------------------
   700 
   701 *** General ***
   702 
   703 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   704 and updated, with formally checked references as hyperlinks.
   705 
   706 * Theory loader: use_thy (and similar operations) no longer set the
   707 implicit ML context, which was occasionally hard to predict and in
   708 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   709 provides a proper context already.
   710 
   711 * Theory loader: old-style ML proof scripts being *attached* to a thy
   712 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   713 'use' within a theory file will do the job.
   714 
   715 * Name space merge now observes canonical order, i.e. the second space
   716 is inserted into the first one, while existing entries in the first
   717 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   718 swap theory imports.
   719 
   720 * Syntax: symbol \<chi> is now considered a letter.  Potential
   721 INCOMPATIBILITY in identifier syntax etc.
   722 
   723 * Outer syntax: string tokens no longer admit escaped white space,
   724 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   725 white space without escapes.
   726 
   727 * Outer syntax: string tokens may contain arbitrary character codes
   728 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   729 "foo_bar".
   730 
   731 
   732 *** Pure ***
   733 
   734 * Context-dependent token translations.  Default setup reverts locally
   735 fixed variables, and adds hilite markup for undeclared frees.
   736 
   737 * Unused theorems can be found using the new command 'unused_thms'.
   738 There are three ways of invoking it:
   739 
   740 (1) unused_thms
   741      Only finds unused theorems in the current theory.
   742 
   743 (2) unused_thms thy_1 ... thy_n -
   744      Finds unused theorems in the current theory and all of its ancestors,
   745      excluding the theories thy_1 ... thy_n and all of their ancestors.
   746 
   747 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   748      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   749      their ancestors, excluding the theories thy_1 ... thy_n and all of
   750      their ancestors.
   751 
   752 In order to increase the readability of the list produced by
   753 unused_thms, theorems that have been created by a particular instance
   754 of a theory command such as 'inductive' or 'function' are considered
   755 to belong to the same "group", meaning that if at least one theorem in
   756 this group is used, the other theorems in the same group are no longer
   757 reported as unused.  Moreover, if all theorems in the group are
   758 unused, only one theorem in the group is displayed.
   759 
   760 Note that proof objects have to be switched on in order for
   761 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   762 usually the case when using Proof General with the default settings).
   763 
   764 * Authentic naming of facts disallows ad-hoc overwriting of previous
   765 theorems within the same name space.  INCOMPATIBILITY, need to remove
   766 duplicate fact bindings, or even accidental fact duplications.  Note
   767 that tools may maintain dynamically scoped facts systematically, using
   768 PureThy.add_thms_dynamic.
   769 
   770 * Command 'hide' now allows to hide from "fact" name space as well.
   771 
   772 * Eliminated destructive theorem database, simpset, claset, and
   773 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   774 update of theories within ML code.
   775 
   776 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   777 INCOMPATIBILITY, object-logics depending on former Pure require
   778 additional setup PureThy.old_appl_syntax_setup; object-logics
   779 depending on former CPure need to refer to Pure.
   780 
   781 * Commands 'use' and 'ML' are now purely functional, operating on
   782 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   783 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   784 INCOMPATIBILITY.
   785 
   786 * Command 'setup': discontinued implicit version with ML reference.
   787 
   788 * Instantiation target allows for simultaneous specification of class
   789 instance operations together with an instantiation proof.
   790 Type-checking phase allows to refer to class operations uniformly.
   791 See src/HOL/Complex/Complex.thy for an Isar example and
   792 src/HOL/Library/Eval.thy for an ML example.
   793 
   794 * Indexing of literal facts: be more serious about including only
   795 facts from the visible specification/proof context, but not the
   796 background context (locale etc.).  Affects `prop` notation and method
   797 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   798 situations.
   799 
   800 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   801 "(open)" option, which used to expose internal bound variables to the
   802 proof text.
   803 
   804 * Isar statements: removed obsolete case "rule_context".
   805 INCOMPATIBILITY, better use explicit fixes/assumes.
   806 
   807 * Locale proofs: default proof step now includes 'unfold_locales';
   808 hence 'proof' without argument may be used to unfold locale
   809 predicates.
   810 
   811 
   812 *** Document preparation ***
   813 
   814 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   815 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   816 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   817 spot); renamed link color from "darkblue" to "linkcolor" (default
   818 value unchanged, can be redefined via \definecolor); no longer sets
   819 "a4paper" option (unnecessary or even intrusive).
   820 
   821 * Antiquotation @{lemma A method} proves proposition A by the given
   822 method (either a method name or a method name plus (optional) method
   823 arguments in parentheses) and prints A just like @{prop A}.
   824 
   825 
   826 *** HOL ***
   827 
   828 * New primrec package.  Specification syntax conforms in style to
   829 definition/function/....  No separate induction rule is provided.  The
   830 "primrec" command distinguishes old-style and new-style specifications
   831 by syntax.  The former primrec package is now named OldPrimrecPackage.
   832 When adjusting theories, beware: constants stemming from new-style
   833 primrec specifications have authentic syntax.
   834 
   835 * Metis prover is now an order of magnitude faster, and also works
   836 with multithreading.
   837 
   838 * Metis: the maximum number of clauses that can be produced from a
   839 theorem is now given by the attribute max_clauses.  Theorems that
   840 exceed this number are ignored, with a warning printed.
   841 
   842 * Sledgehammer no longer produces structured proofs by default. To
   843 enable, declare [[sledgehammer_full = true]].  Attributes
   844 reconstruction_modulus, reconstruction_sorts renamed
   845 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   846 
   847 * Method "induct_scheme" derives user-specified induction rules
   848 from well-founded induction and completeness of patterns. This factors
   849 out some operations that are done internally by the function package
   850 and makes them available separately.  See
   851 src/HOL/ex/Induction_Scheme.thy for examples.
   852 
   853 * More flexible generation of measure functions for termination
   854 proofs: Measure functions can be declared by proving a rule of the
   855 form "is_measure f" and giving it the [measure_function] attribute.
   856 The "is_measure" predicate is logically meaningless (always true), and
   857 just guides the heuristic.  To find suitable measure functions, the
   858 termination prover sets up the goal "is_measure ?f" of the appropriate
   859 type and generates all solutions by prolog-style backwards proof using
   860 the declared rules.
   861 
   862 This setup also deals with rules like 
   863 
   864   "is_measure f ==> is_measure (list_size f)"
   865 
   866 which accommodates nested datatypes that recurse through lists.
   867 Similar rules are predeclared for products and option types.
   868 
   869 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   870 
   871   INCOMPATIBILITIES:
   872 
   873   - Definitions of overloaded constants on sets have to be replaced by
   874     definitions on => and bool.
   875 
   876   - Some definitions of overloaded operators on sets can now be proved
   877     using the definitions of the operators on => and bool.  Therefore,
   878     the following theorems have been renamed:
   879 
   880       subset_def   -> subset_eq
   881       psubset_def  -> psubset_eq
   882       set_diff_def -> set_diff_eq
   883       Compl_def    -> Compl_eq
   884       Sup_set_def  -> Sup_set_eq
   885       Inf_set_def  -> Inf_set_eq
   886       sup_set_def  -> sup_set_eq
   887       inf_set_def  -> inf_set_eq
   888 
   889   - Due to the incompleteness of the HO unification algorithm, some
   890     rules such as subst may require manual instantiation, if some of
   891     the unknowns in the rule is a set.
   892 
   893   - Higher order unification and forward proofs:
   894     The proof pattern
   895 
   896       have "P (S::'a set)" <...>
   897       then have "EX S. P S" ..
   898 
   899     no longer works (due to the incompleteness of the HO unification
   900     algorithm) and must be replaced by the pattern
   901 
   902       have "EX S. P S"
   903       proof
   904         show "P S" <...>
   905       qed
   906 
   907   - Calculational reasoning with subst (or similar rules):
   908     The proof pattern
   909 
   910       have "P (S::'a set)" <...>
   911       also have "S = T" <...>
   912       finally have "P T" .
   913 
   914     no longer works (for similar reasons as the previous example) and
   915     must be replaced by something like
   916 
   917       have "P (S::'a set)" <...>
   918       moreover have "S = T" <...>
   919       ultimately have "P T" by simp
   920 
   921   - Tactics or packages written in ML code:
   922     Code performing pattern matching on types via
   923 
   924       Type ("set", [T]) => ...
   925 
   926     must be rewritten. Moreover, functions like strip_type or
   927     binder_types no longer return the right value when applied to a
   928     type of the form
   929 
   930       T1 => ... => Tn => U => bool
   931 
   932     rather than
   933 
   934       T1 => ... => Tn => U set
   935 
   936 * Merged theories Wellfounded_Recursion, Accessible_Part and
   937 Wellfounded_Relations to theory Wellfounded.
   938 
   939 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   940 
   941 * Class finite no longer treats UNIV as class parameter.  Use class
   942 enum from theory Library/Enum instead to achieve a similar effect.
   943 INCOMPATIBILITY.
   944 
   945 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   946 and "Cons".  INCOMPATIBILITY.
   947 
   948 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   949 Potential INCOMPATIBILITY.
   950 
   951 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   952 injective_fst_snd removed, use split_eta and prod_eqI instead.
   953 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   954 
   955 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   956 the same name in theory Orderings:
   957 
   958   less_trans
   959   less_linear
   960   le_imp_less_or_eq
   961   le_less_trans
   962   less_le_trans
   963   less_not_sym
   964   less_asym
   965 
   966 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   967 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   968 and different variable names.
   969 
   970 * Library/Option_ord.thy: Canonical order on option type.
   971 
   972 * Library/RBT.thy: Red-black trees, an efficient implementation of
   973 finite maps.
   974 
   975 * Library/Countable.thy: Type class for countable types.
   976 
   977 * Theory Int: The representation of numerals has changed.  The infix
   978 operator BIT and the bit datatype with constructors B0 and B1 have
   979 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   980 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   981 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   982 accordingly.
   983 
   984 * Theory Nat: definition of <= and < on natural numbers no longer
   985 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   986 le_def and less_def have disappeared.  Consider lemmas not_less
   987 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   988 
   989 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   990 (whose purpose mainly is for various fold_set functionals) have been
   991 abandoned in favor of the existing algebraic classes
   992 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   993 lower_semilattice (resp. upper_semilattice) and linorder.
   994 INCOMPATIBILITY.
   995 
   996 * Theory Transitive_Closure: induct and cases rules now declare proper
   997 case_names ("base" and "step").  INCOMPATIBILITY.
   998 
   999 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1000 lattices.  The form set-specific version is available as
  1001 Inductive.lfp_ordinal_induct_set.
  1002 
  1003 * Renamed theorems "power.simps" to "power_int.simps".
  1004 INCOMPATIBILITY.
  1005 
  1006 * Class semiring_div provides basic abstract properties of semirings
  1007 with division and modulo operations.  Subsumes former class dvd_mod.
  1008 
  1009 * Merged theories IntDef, Numeral and IntArith into unified theory
  1010 Int.  INCOMPATIBILITY.
  1011 
  1012 * Theory Library/Code_Index: type "index" now represents natural
  1013 numbers rather than integers.  INCOMPATIBILITY.
  1014 
  1015 * New class "uminus" with operation "uminus" (split of from class
  1016 "minus" which now only has operation "minus", binary).
  1017 INCOMPATIBILITY.
  1018 
  1019 * Constants "card", "internal_split", "option_map" now with authentic
  1020 syntax.  INCOMPATIBILITY.
  1021 
  1022 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1023 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1024 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1025 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1026 Sup_set_def, le_def, less_def, option_map_def now with object
  1027 equality.  INCOMPATIBILITY.
  1028 
  1029 * Records. Removed K_record, and replaced it by pure lambda term
  1030 %x. c. The simplifier setup is now more robust against eta expansion.
  1031 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1032 
  1033 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1034 
  1035 * Library/ListVector: new theory of arithmetic vector operations.
  1036 
  1037 * Library/Order_Relation: new theory of various orderings as sets of
  1038 pairs.  Defines preorders, partial orders, linear orders and
  1039 well-orders on sets and on types.
  1040 
  1041 
  1042 *** ZF ***
  1043 
  1044 * Renamed some theories to allow to loading both ZF and HOL in the
  1045 same session:
  1046 
  1047   Datatype  -> Datatype_ZF
  1048   Inductive -> Inductive_ZF
  1049   Int       -> Int_ZF
  1050   IntDiv    -> IntDiv_ZF
  1051   Nat       -> Nat_ZF
  1052   List      -> List_ZF
  1053   Main      -> Main_ZF
  1054 
  1055 INCOMPATIBILITY: ZF theories that import individual theories below
  1056 Main might need to be adapted.  Regular theory Main is still
  1057 available, as trivial extension of Main_ZF.
  1058 
  1059 
  1060 *** ML ***
  1061 
  1062 * ML within Isar: antiquotation @{const name} or @{const
  1063 name(typargs)} produces statically-checked Const term.
  1064 
  1065 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1066 (of the same name).  Removed obsolete print command.
  1067 
  1068 * Removed obsolete "use_legacy_bindings" function.
  1069 
  1070 * The ``print mode'' is now a thread-local value derived from a global
  1071 template (the former print_mode reference), thus access becomes
  1072 non-critical.  The global print_mode reference is for session
  1073 management only; user-code should use print_mode_value,
  1074 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1075 
  1076 * Functions system/system_out provide a robust way to invoke external
  1077 shell commands, with propagation of interrupts (requires Poly/ML
  1078 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1079 
  1080 
  1081 *** System ***
  1082 
  1083 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1084 in accordance with Proof General 3.7, which prefers GNU emacs.
  1085 
  1086 * isatool tty runs Isabelle process with plain tty interaction;
  1087 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1088 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1089 
  1090 * isatool browser now works with Cygwin as well, using general
  1091 "javapath" function defined in Isabelle process environment.
  1092 
  1093 * YXML notation provides a simple and efficient alternative to
  1094 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1095 isatool yxml as described in the Isabelle system manual.
  1096 
  1097 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1098 provides general wrapper for managing an Isabelle process in a robust
  1099 fashion, with ``cooked'' output from stdin/stderr.
  1100 
  1101 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1102 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1103 
  1104 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1105 way of changing the user's settings is via
  1106 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1107 script.
  1108 
  1109 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1110 cores of the underlying machine, which is a good starting point for
  1111 optimal performance tuning.  The corresponding usedir option -M allows
  1112 "max" as an alias for "0".  WARNING: does not work on certain versions
  1113 of Mac OS (with Poly/ML 5.1).
  1114 
  1115 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1116 adverse effect of Isabelle flooding interactive front-ends (notably
  1117 ProofGeneral / XEmacs).
  1118 
  1119 
  1120 
  1121 New in Isabelle2007 (November 2007)
  1122 -----------------------------------
  1123 
  1124 *** General ***
  1125 
  1126 * More uniform information about legacy features, notably a
  1127 warning/error of "Legacy feature: ...", depending on the state of the
  1128 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1129 legacy features will disappear eventually.
  1130 
  1131 * Theory syntax: the header format ``theory A = B + C:'' has been
  1132 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1133 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1134 
  1135 * Theory syntax: the old non-Isar theory file format has been
  1136 discontinued altogether.  Note that ML proof scripts may still be used
  1137 with Isar theories; migration is usually quite simple with the ML
  1138 function use_legacy_bindings.  INCOMPATIBILITY.
  1139 
  1140 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1141 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1142 quotes.
  1143 
  1144 * Theory loader: be more serious about observing the static theory
  1145 header specifications (including optional directories), but not the
  1146 accidental file locations of previously successful loads.  The strict
  1147 update policy of former update_thy is now already performed by
  1148 use_thy, so the former has been removed; use_thys updates several
  1149 theories simultaneously, just as 'imports' within a theory header
  1150 specification, but without merging the results.  Potential
  1151 INCOMPATIBILITY: may need to refine theory headers and commands
  1152 ROOT.ML which depend on load order.
  1153 
  1154 * Theory loader: optional support for content-based file
  1155 identification, instead of the traditional scheme of full physical
  1156 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1157 (cf. the system manual).  The new scheme allows to work with
  1158 non-finished theories in persistent session images, such that source
  1159 files may be moved later on without requiring reloads.
  1160 
  1161 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1162 file (with the same base name as the theory) are considered a legacy
  1163 feature, which will disappear eventually. Even now, the theory loader
  1164 no longer maintains dependencies on such files.
  1165 
  1166 * Syntax: the scope for resolving ambiguities via type-inference is
  1167 now limited to individual terms, instead of whole simultaneous
  1168 specifications as before. This greatly reduces the complexity of the
  1169 syntax module and improves flexibility by separating parsing and
  1170 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1171 'fixes' etc.) are required in rare situations.
  1172 
  1173 * Syntax: constants introduced by new-style packages ('definition',
  1174 'abbreviation' etc.) are passed through the syntax module in
  1175 ``authentic mode''. This means that associated mixfix annotations
  1176 really stick to such constants, independently of potential name space
  1177 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1178 trees are represented slightly differently, may need to adapt syntax
  1179 translations accordingly. Use CONST marker in 'translations' and
  1180 @{const_syntax} antiquotation in 'parse_translation' etc.
  1181 
  1182 * Legacy goal package: reduced interface to the bare minimum required
  1183 to keep existing proof scripts running.  Most other user-level
  1184 functions are now part of the OldGoals structure, which is *not* open
  1185 by default (consider isatool expandshort before open OldGoals).
  1186 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1187 these tend to cause confusion about the actual goal (!) context being
  1188 used here, which is not necessarily the same as the_context().
  1189 
  1190 * Command 'find_theorems': supports "*" wild-card in "name:"
  1191 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1192 support a specific search form (see ProofGeneral/CHANGES).
  1193 
  1194 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1195 by default, which means that "prems" (and also "fixed variables") are
  1196 suppressed from proof state output.  Note that the ProofGeneral
  1197 settings mechanism allows to change and save options persistently, but
  1198 older versions of Isabelle will fail to start up if a negative prems
  1199 limit is imposed.
  1200 
  1201 * Local theory targets may be specified by non-nested blocks of
  1202 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1203 contain definitions, theorems etc., including any derived mechanism
  1204 that has been implemented on top of these primitives.  This concept
  1205 generalizes the existing ``theorem (in ...)'' towards more versatility
  1206 and scalability.
  1207 
  1208 * Proof General interface: proper undo of final 'end' command;
  1209 discontinued Isabelle/classic mode (ML proof scripts).
  1210 
  1211 
  1212 *** Document preparation ***
  1213 
  1214 * Added antiquotation @{theory name} which prints the given name,
  1215 after checking that it refers to a valid ancestor theory in the
  1216 current context.
  1217 
  1218 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1219 check the given source text as ML type/structure, printing verbatim.
  1220 
  1221 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1222 "c args == rhs" given in the current context.  (Any number of
  1223 arguments may be given on the LHS.)
  1224 
  1225 
  1226 *** Pure ***
  1227 
  1228 * The 'class' package offers a combination of axclass and locale to
  1229 achieve Haskell-like type classes in Isabelle.  Definitions and
  1230 theorems within a class context produce both relative results (with
  1231 implicit parameters according to the locale context), and polymorphic
  1232 constants with qualified polymorphism (according to the class
  1233 context).  Within the body context of a 'class' target, a separate
  1234 syntax layer ("user space type system") takes care of converting
  1235 between global polymorphic consts and internal locale representation.
  1236 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1237 "isatool doc classes" provides a tutorial.
  1238 
  1239 * Generic code generator framework allows to generate executable
  1240 code for ML and Haskell (including Isabelle classes).  A short usage
  1241 sketch:
  1242 
  1243     internal compilation:
  1244         export_code <list of constants (term syntax)> in SML
  1245     writing SML code to a file:
  1246         export_code <list of constants (term syntax)> in SML <filename>
  1247     writing OCaml code to a file:
  1248         export_code <list of constants (term syntax)> in OCaml <filename>
  1249     writing Haskell code to a bunch of files:
  1250         export_code <list of constants (term syntax)> in Haskell <filename>
  1251 
  1252     evaluating closed propositions to True/False using code generation:
  1253         method ``eval''
  1254 
  1255 Reasonable default setup of framework in HOL.
  1256 
  1257 Theorem attributs for selecting and transforming function equations theorems:
  1258 
  1259     [code fun]:        select a theorem as function equation for a specific constant
  1260     [code fun del]:    deselect a theorem as function equation for a specific constant
  1261     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1262     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1263 
  1264 User-defined serializations (target in {SML, OCaml, Haskell}):
  1265 
  1266     code_const <and-list of constants (term syntax)>
  1267       {(target) <and-list of const target syntax>}+
  1268 
  1269     code_type <and-list of type constructors>
  1270       {(target) <and-list of type target syntax>}+
  1271 
  1272     code_instance <and-list of instances>
  1273       {(target)}+
  1274         where instance ::= <type constructor> :: <class>
  1275 
  1276     code_class <and_list of classes>
  1277       {(target) <and-list of class target syntax>}+
  1278         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1279 
  1280 code_instance and code_class only are effective to target Haskell.
  1281 
  1282 For example usage see src/HOL/ex/Codegenerator.thy and
  1283 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1284 generation from Isabelle/HOL theories is available via "isatool doc
  1285 codegen".
  1286 
  1287 * Code generator: consts in 'consts_code' Isar commands are now
  1288 referred to by usual term syntax (including optional type
  1289 annotations).
  1290 
  1291 * Command 'no_translations' removes translation rules from theory
  1292 syntax.
  1293 
  1294 * Overloaded definitions are now actually checked for acyclic
  1295 dependencies.  The overloading scheme is slightly more general than
  1296 that of Haskell98, although Isabelle does not demand an exact
  1297 correspondence to type class and instance declarations.
  1298 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1299 exotic versions of overloading -- at the discretion of the user!
  1300 
  1301 Polymorphic constants are represented via type arguments, i.e. the
  1302 instantiation that matches an instance against the most general
  1303 declaration given in the signature.  For example, with the declaration
  1304 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1305 as c(nat).  Overloading is essentially simultaneous structural
  1306 recursion over such type arguments.  Incomplete specification patterns
  1307 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1308 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1309 Command 'print_theory' outputs the normalized system of recursive
  1310 equations, see section "definitions".
  1311 
  1312 * Configuration options are maintained within the theory or proof
  1313 context (with name and type bool/int/string), providing a very simple
  1314 interface to a poor-man's version of general context data.  Tools may
  1315 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1316 these values using Config.get etc.  Users may change options via an
  1317 associated attribute of the same name.  This form of context
  1318 declaration works particularly well with commands 'declare' or
  1319 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1320 very easy to avoid global references, which would not observe Isar
  1321 toplevel undo/redo and fail to work with multithreading.
  1322 
  1323 Various global ML references of Pure and HOL have been turned into
  1324 configuration options:
  1325 
  1326   Unify.search_bound		unify_search_bound
  1327   Unify.trace_bound		unify_trace_bound
  1328   Unify.trace_simp		unify_trace_simp
  1329   Unify.trace_types		unify_trace_types
  1330   Simplifier.simp_depth_limit	simp_depth_limit
  1331   Blast.depth_limit		blast_depth_limit
  1332   DatatypeProp.dtK		datatype_distinctness_limit
  1333   fast_arith_neq_limit  	fast_arith_neq_limit
  1334   fast_arith_split_limit	fast_arith_split_limit
  1335 
  1336 * Named collections of theorems may be easily installed as context
  1337 data using the functor NamedThmsFun (see also
  1338 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1339 attributes; there is also a toplevel print command.  This facility is
  1340 just a common case of general context data, which is the preferred way
  1341 for anything more complex than just a list of facts in canonical
  1342 order.
  1343 
  1344 * Isar: command 'declaration' augments a local theory by generic
  1345 declaration functions written in ML.  This enables arbitrary content
  1346 being added to the context, depending on a morphism that tells the
  1347 difference of the original declaration context wrt. the application
  1348 context encountered later on.
  1349 
  1350 * Isar: proper interfaces for simplification procedures.  Command
  1351 'simproc_setup' declares named simprocs (with match patterns, and body
  1352 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1353 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1354 
  1355 * Isar: an extra pair of brackets around attribute declarations
  1356 abbreviates a theorem reference involving an internal dummy fact,
  1357 which will be ignored later --- only the effect of the attribute on
  1358 the background context will persist.  This form of in-place
  1359 declarations is particularly useful with commands like 'declare' and
  1360 'using', for example ``have A using [[simproc a]] by simp''.
  1361 
  1362 * Isar: method "assumption" (and implicit closing of subproofs) now
  1363 takes simple non-atomic goal assumptions into account: after applying
  1364 an assumption as a rule the resulting subgoals are solved by atomic
  1365 assumption steps.  This is particularly useful to finish 'obtain'
  1366 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1367 without referring to the original premise "!!x. P x ==> thesis" in the
  1368 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1369 more permissive.
  1370 
  1371 * Isar: implicit use of prems from the Isar proof context is
  1372 considered a legacy feature.  Common applications like ``have A .''
  1373 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1374 referencing facts explicitly here improves readability and
  1375 maintainability of proof texts.
  1376 
  1377 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1378 the obtained context from the course of reasoning!  For example:
  1379 
  1380   assume "EX x y. A x & B y"   -- "any previous fact"
  1381   then guess x and y by clarify
  1382 
  1383 This technique is potentially adventurous, depending on the facts and
  1384 proof tools being involved here.
  1385 
  1386 * Isar: known facts from the proof context may be specified as literal
  1387 propositions, using ASCII back-quote syntax.  This works wherever
  1388 named facts used to be allowed so far, in proof commands, proof
  1389 methods, attributes etc.  Literal facts are retrieved from the context
  1390 according to unification of type and term parameters.  For example,
  1391 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1392 theorems in the current context, then these are valid literal facts:
  1393 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1394 
  1395 There is also a proof method "fact" which does the same composition
  1396 for explicit goal states, e.g. the following proof texts coincide with
  1397 certain special cases of literal facts:
  1398 
  1399   have "A" by fact                 ==  note `A`
  1400   have "A ==> B" by fact           ==  note `A ==> B`
  1401   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1402   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1403 
  1404 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1405 outer syntax.  Thus symbolic identifiers may be used without
  1406 additional white space in declarations like this: ``assume *: A''.
  1407 
  1408 * Isar: 'print_facts' prints all local facts of the current context,
  1409 both named and unnamed ones.
  1410 
  1411 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1412 
  1413   def x == "t" and y == "u"
  1414 
  1415 * Isar: added command 'unfolding', which is structurally similar to
  1416 'using', but affects both the goal state and facts by unfolding given
  1417 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1418 'unfolded' attribute may be replaced by first-class proof text.
  1419 
  1420 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1421 and command 'unfolding' now all support object-level equalities
  1422 (potentially conditional).  The underlying notion of rewrite rule is
  1423 analogous to the 'rule_format' attribute, but *not* that of the
  1424 Simplifier (which is usually more generous).
  1425 
  1426 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1427 premises of a theorem by n. Useful in conjunction with drule.
  1428 
  1429 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1430 method expression within a sandbox consisting of the first N
  1431 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1432 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1433 simplifies all new goals that emerge from applying rule foo to the
  1434 originally first one.
  1435 
  1436 * Isar: schematic goals are no longer restricted to higher-order
  1437 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1438 expected.
  1439 
  1440 * Isar: the conclusion of a long theorem statement is now either
  1441 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1442 (essentially a disjunction of cases with local parameters and
  1443 assumptions).  The latter allows to express general elimination rules
  1444 adequately; in this notation common elimination rules look like this:
  1445 
  1446   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1447     assumes "EX x. P x"
  1448     obtains x where "P x"
  1449 
  1450   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1451     assumes "A & B"
  1452     obtains A and B
  1453 
  1454   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1455     assumes "A | B"
  1456     obtains
  1457       A
  1458     | B
  1459 
  1460 The subsequent classical rules even refer to the formal "thesis"
  1461 explicitly:
  1462 
  1463   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1464     obtains "~ thesis"
  1465 
  1466   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1467     obtains "thesis ==> something"
  1468 
  1469 The actual proof of an 'obtains' statement is analogous to that of the
  1470 Isar proof element 'obtain', only that there may be several cases.
  1471 Optional case names may be specified in parentheses; these will be
  1472 available both in the present proof and as annotations in the
  1473 resulting rule, for later use with the 'cases' method (cf. attribute
  1474 case_names).
  1475 
  1476 * Isar: the assumptions of a long theorem statement are available as
  1477 "assms" fact in the proof context.  This is more appropriate than the
  1478 (historical) "prems", which refers to all assumptions of the current
  1479 context, including those from the target locale, proof body etc.
  1480 
  1481 * Isar: 'print_statement' prints theorems from the current theory or
  1482 proof context in long statement form, according to the syntax of a
  1483 top-level lemma.
  1484 
  1485 * Isar: 'obtain' takes an optional case name for the local context
  1486 introduction rule (default "that").
  1487 
  1488 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1489 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1490 to occur.
  1491 
  1492 * Pure: syntax "CONST name" produces a fully internalized constant
  1493 according to the current context.  This is particularly useful for
  1494 syntax translations that should refer to internal constant
  1495 representations independently of name spaces.
  1496 
  1497 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1498 instead of "FOO ". This allows multiple binder declarations to coexist
  1499 in the same context.  INCOMPATIBILITY.
  1500 
  1501 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1502 primitive that also works in a locale context (both for constants and
  1503 fixed variables). Type declaration and internal syntactic representation
  1504 of given constants retrieved from the context. Likewise, the
  1505 'no_notation' command allows to remove given syntax annotations from the
  1506 current context.
  1507 
  1508 * Isar/locales: new derived specification elements 'axiomatization',
  1509 'definition', 'abbreviation', which support type-inference, admit
  1510 object-level specifications (equality, equivalence).  See also the
  1511 isar-ref manual.  Examples:
  1512 
  1513   axiomatization
  1514     eq  (infix "===" 50) where
  1515     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1516 
  1517   definition "f x y = x + y + 1"
  1518   definition g where "g x = f x x"
  1519 
  1520   abbreviation
  1521     neq  (infix "=!=" 50) where
  1522     "x =!= y == ~ (x === y)"
  1523 
  1524 These specifications may be also used in a locale context.  Then the
  1525 constants being introduced depend on certain fixed parameters, and the
  1526 constant name is qualified by the locale base name.  An internal
  1527 abbreviation takes care for convenient input and output, making the
  1528 parameters implicit and using the original short name.  See also
  1529 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1530 entities from a monomorphic theory.
  1531 
  1532 Presently, abbreviations are only available 'in' a target locale, but
  1533 not inherited by general import expressions.  Also note that
  1534 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1535 'translations' in common applications.  The "no_abbrevs" print mode
  1536 prevents folding of abbreviations in term output.
  1537 
  1538 Concrete syntax is attached to specified constants in internal form,
  1539 independently of name spaces.  The parse tree representation is
  1540 slightly different -- use 'notation' instead of raw 'syntax', and
  1541 'translations' with explicit "CONST" markup to accommodate this.
  1542 
  1543 * Pure/Isar: unified syntax for new-style specification mechanisms
  1544 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1545 full type inference and dummy patterns ("_").  For example:
  1546 
  1547   definition "K x _ = x"
  1548 
  1549   inductive conj for A B
  1550   where "A ==> B ==> conj A B"
  1551 
  1552 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1553 the current context.  Print mode "no_abbrevs" prevents inversion of
  1554 abbreviations on output.
  1555 
  1556 * Isar/locales: improved parameter handling: use of locales "var" and
  1557 "struct" no longer necessary; - parameter renamings are no longer
  1558 required to be injective.  For example, this allows to define
  1559 endomorphisms as locale endom = homom mult mult h.
  1560 
  1561 * Isar/locales: changed the way locales with predicates are defined.
  1562 Instead of accumulating the specification, the imported expression is
  1563 now an interpretation.  INCOMPATIBILITY: different normal form of
  1564 locale expressions.  In particular, in interpretations of locales with
  1565 predicates, goals repesenting already interpreted fragments are not
  1566 removed automatically.  Use methods `intro_locales' and
  1567 `unfold_locales'; see below.
  1568 
  1569 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1570 provide backward reasoning on locales predicates.  The methods are
  1571 aware of interpretations and discharge corresponding goals.
  1572 `intro_locales' is less aggressive then `unfold_locales' and does not
  1573 unfold predicates to assumptions.
  1574 
  1575 * Isar/locales: the order in which locale fragments are accumulated
  1576 has changed.  This enables to override declarations from fragments due
  1577 to interpretations -- for example, unwanted simp rules.
  1578 
  1579 * Isar/locales: interpretation in theories and proof contexts has been
  1580 extended.  One may now specify (and prove) equations, which are
  1581 unfolded in interpreted theorems.  This is useful for replacing
  1582 defined concepts (constants depending on locale parameters) by
  1583 concepts already existing in the target context.  Example:
  1584 
  1585   interpretation partial_order ["op <= :: [int, int] => bool"]
  1586     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1587 
  1588 Typically, the constant `partial_order.less' is created by a
  1589 definition specification element in the context of locale
  1590 partial_order.
  1591 
  1592 * Method "induct": improved internal context management to support
  1593 local fixes and defines on-the-fly. Thus explicit meta-level
  1594 connectives !!  and ==> are rarely required anymore in inductive goals
  1595 (using object-logic connectives for this purpose has been long
  1596 obsolete anyway). Common proof patterns are explained in
  1597 src/HOL/Induct/Common_Patterns.thy, see also
  1598 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1599 examples.
  1600 
  1601 * Method "induct": improved handling of simultaneous goals. Instead of
  1602 introducing object-level conjunction, the statement is now split into
  1603 several conclusions, while the corresponding symbolic cases are nested
  1604 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1605 see src/HOL/Induct/Common_Patterns.thy, for example.
  1606 
  1607 * Method "induct": mutual induction rules are now specified as a list
  1608 of rule sharing the same induction cases. HOL packages usually provide
  1609 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1610 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1611 mutual induction rules differently, i.e. like this:
  1612 
  1613   (induct rule: foo_bar.inducts)
  1614   (induct set: foo bar)
  1615   (induct pred: foo bar)
  1616   (induct type: foo bar)
  1617 
  1618 The ML function ProjectRule.projections turns old-style rules into the
  1619 new format.
  1620 
  1621 * Method "coinduct": dual of induction, see
  1622 src/HOL/Library/Coinductive_List.thy for various examples.
  1623 
  1624 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1625 considered a legacy feature.
  1626 
  1627 * Attribute "symmetric" produces result with standardized schematic
  1628 variables (index 0).  Potential INCOMPATIBILITY.
  1629 
  1630 * Simplifier: by default the simplifier trace only shows top level
  1631 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1632 default. Thus there is less danger of being flooded by the trace. The
  1633 trace indicates where parts have been suppressed.
  1634   
  1635 * Provers/classical: removed obsolete classical version of elim_format
  1636 attribute; classical elim/dest rules are now treated uniformly when
  1637 manipulating the claset.
  1638 
  1639 * Provers/classical: stricter checks to ensure that supplied intro,
  1640 dest and elim rules are well-formed; dest and elim rules must have at
  1641 least one premise.
  1642 
  1643 * Provers/classical: attributes dest/elim/intro take an optional
  1644 weight argument for the rule (just as the Pure versions).  Weights are
  1645 ignored by automated tools, but determine the search order of single
  1646 rule steps.
  1647 
  1648 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1649 where the body does not mention the bound variable.  Note that dummy
  1650 patterns implicitly depend on their context of bounds, which makes
  1651 "{_. _}" match any set comprehension as expected.  Potential
  1652 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1653 constant "_idtdummy" in the binding position.
  1654 
  1655 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1656 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1657 for example "A -> B" => "Pi A (%_. B)".
  1658 
  1659 * Pure: 'class_deps' command visualizes the subclass relation, using
  1660 the graph browser tool.
  1661 
  1662 * Pure: 'print_theory' now suppresses certain internal declarations by
  1663 default; use '!' option for full details.
  1664 
  1665 
  1666 *** HOL ***
  1667 
  1668 * Method "metis" proves goals by applying the Metis general-purpose
  1669 resolution prover (see also http://gilith.com/software/metis/).
  1670 Examples are in the directory MetisExamples.  WARNING: the
  1671 Isabelle/HOL-Metis integration does not yet work properly with
  1672 multi-threading.
  1673   
  1674 * Command 'sledgehammer' invokes external automatic theorem provers as
  1675 background processes.  It generates calls to the "metis" method if
  1676 successful. These can be pasted into the proof.  Users do not have to
  1677 wait for the automatic provers to return.  WARNING: does not really
  1678 work with multi-threading.
  1679 
  1680 * New "auto_quickcheck" feature tests outermost goal statements for
  1681 potential counter-examples.  Controlled by ML references
  1682 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1683 5000 milliseconds).  Fails silently if statements is outside of
  1684 executable fragment, or any other codgenerator problem occurs.
  1685 
  1686 * New constant "undefined" with axiom "undefined x = undefined".
  1687 
  1688 * Added class "HOL.eq", allowing for code generation with polymorphic
  1689 equality.
  1690 
  1691 * Some renaming of class constants due to canonical name prefixing in
  1692 the new 'class' package:
  1693 
  1694     HOL.abs ~> HOL.abs_class.abs
  1695     HOL.divide ~> HOL.divide_class.divide
  1696     0 ~> HOL.zero_class.zero
  1697     1 ~> HOL.one_class.one
  1698     op + ~> HOL.plus_class.plus
  1699     op - ~> HOL.minus_class.minus
  1700     uminus ~> HOL.minus_class.uminus
  1701     op * ~> HOL.times_class.times
  1702     op < ~> HOL.ord_class.less
  1703     op <= > HOL.ord_class.less_eq
  1704     Nat.power ~> Power.power_class.power
  1705     Nat.size ~> Nat.size_class.size
  1706     Numeral.number_of ~> Numeral.number_class.number_of
  1707     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1708     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1709     Orderings.min ~> Orderings.ord_class.min
  1710     Orderings.max ~> Orderings.ord_class.max
  1711     Divides.op div ~> Divides.div_class.div
  1712     Divides.op mod ~> Divides.div_class.mod
  1713     Divides.op dvd ~> Divides.div_class.dvd
  1714 
  1715 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1716 
  1717 a) User-defined constants using any of the names "plus", "minus",
  1718 "times", "less" or "less_eq". The standard syntax translations for
  1719 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1720 names.
  1721 
  1722 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1723 INCOMPATIBILITY: use more specific names.
  1724 
  1725 c) Permutative equations (e.g. "a + b = b + a")
  1726 Since the change of names also changes the order of terms, permutative
  1727 rewrite rules may get applied in a different order. Experience shows
  1728 that this is rarely the case (only two adaptions in the whole Isabelle
  1729 distribution).  INCOMPATIBILITY: rewrite proofs
  1730 
  1731 d) ML code directly refering to constant names
  1732 This in general only affects hand-written proof tactics, simprocs and
  1733 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1734 Consider using @{const_name} antiquotation.
  1735 
  1736 * New class "default" with associated constant "default".
  1737 
  1738 * Function "sgn" is now overloaded and available on int, real, complex
  1739 (and other numeric types), using class "sgn".  Two possible defs of
  1740 sgn are given as equational assumptions in the classes sgn_if and
  1741 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1742 INCOMPATIBILITY.
  1743 
  1744 * Locale "partial_order" now unified with class "order" (cf. theory
  1745 Orderings), added parameter "less".  INCOMPATIBILITY.
  1746 
  1747 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1748 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1749 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1750 
  1751 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1752 changed order of proof goals in instance proofs.
  1753 
  1754 * The transitivity reasoner for partial and linear orders is set up
  1755 for classes "order" and "linorder".  Instances of the reasoner are available
  1756 in all contexts importing or interpreting the corresponding locales.
  1757 Method "order" invokes the reasoner separately; the reasoner
  1758 is also integrated with the Simplifier as a solver.  Diagnostic
  1759 command 'print_orders' shows the available instances of the reasoner
  1760 in the current context.
  1761 
  1762 * Localized monotonicity predicate in theory "Orderings"; integrated
  1763 lemmas max_of_mono and min_of_mono with this predicate.
  1764 INCOMPATIBILITY.
  1765 
  1766 * Formulation of theorem "dense" changed slightly due to integration
  1767 with new class dense_linear_order.
  1768 
  1769 * Uniform lattice theory development in HOL.
  1770 
  1771     constants "meet" and "join" now named "inf" and "sup"
  1772     constant "Meet" now named "Inf"
  1773 
  1774     classes "meet_semilorder" and "join_semilorder" now named
  1775       "lower_semilattice" and "upper_semilattice"
  1776     class "lorder" now named "lattice"
  1777     class "comp_lat" now named "complete_lattice"
  1778 
  1779     Instantiation of lattice classes allows explicit definitions
  1780     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1781 
  1782   INCOMPATIBILITY.  Theorem renames:
  1783 
  1784     meet_left_le            ~> inf_le1
  1785     meet_right_le           ~> inf_le2
  1786     join_left_le            ~> sup_ge1
  1787     join_right_le           ~> sup_ge2
  1788     meet_join_le            ~> inf_sup_ord
  1789     le_meetI                ~> le_infI
  1790     join_leI                ~> le_supI
  1791     le_meet                 ~> le_inf_iff
  1792     le_join                 ~> ge_sup_conv
  1793     meet_idempotent         ~> inf_idem
  1794     join_idempotent         ~> sup_idem
  1795     meet_comm               ~> inf_commute
  1796     join_comm               ~> sup_commute
  1797     meet_leI1               ~> le_infI1
  1798     meet_leI2               ~> le_infI2
  1799     le_joinI1               ~> le_supI1
  1800     le_joinI2               ~> le_supI2
  1801     meet_assoc              ~> inf_assoc
  1802     join_assoc              ~> sup_assoc
  1803     meet_left_comm          ~> inf_left_commute
  1804     meet_left_idempotent    ~> inf_left_idem
  1805     join_left_comm          ~> sup_left_commute
  1806     join_left_idempotent    ~> sup_left_idem
  1807     meet_aci                ~> inf_aci
  1808     join_aci                ~> sup_aci
  1809     le_def_meet             ~> le_iff_inf
  1810     le_def_join             ~> le_iff_sup
  1811     join_absorp2            ~> sup_absorb2
  1812     join_absorp1            ~> sup_absorb1
  1813     meet_absorp1            ~> inf_absorb1
  1814     meet_absorp2            ~> inf_absorb2
  1815     meet_join_absorp        ~> inf_sup_absorb
  1816     join_meet_absorp        ~> sup_inf_absorb
  1817     distrib_join_le         ~> distrib_sup_le
  1818     distrib_meet_le         ~> distrib_inf_le
  1819 
  1820     add_meet_distrib_left   ~> add_inf_distrib_left
  1821     add_join_distrib_left   ~> add_sup_distrib_left
  1822     is_join_neg_meet        ~> is_join_neg_inf
  1823     is_meet_neg_join        ~> is_meet_neg_sup
  1824     add_meet_distrib_right  ~> add_inf_distrib_right
  1825     add_join_distrib_right  ~> add_sup_distrib_right
  1826     add_meet_join_distribs  ~> add_sup_inf_distribs
  1827     join_eq_neg_meet        ~> sup_eq_neg_inf
  1828     meet_eq_neg_join        ~> inf_eq_neg_sup
  1829     add_eq_meet_join        ~> add_eq_inf_sup
  1830     meet_0_imp_0            ~> inf_0_imp_0
  1831     join_0_imp_0            ~> sup_0_imp_0
  1832     meet_0_eq_0             ~> inf_0_eq_0
  1833     join_0_eq_0             ~> sup_0_eq_0
  1834     neg_meet_eq_join        ~> neg_inf_eq_sup
  1835     neg_join_eq_meet        ~> neg_sup_eq_inf
  1836     join_eq_if              ~> sup_eq_if
  1837 
  1838     mono_meet               ~> mono_inf
  1839     mono_join               ~> mono_sup
  1840     meet_bool_eq            ~> inf_bool_eq
  1841     join_bool_eq            ~> sup_bool_eq
  1842     meet_fun_eq             ~> inf_fun_eq
  1843     join_fun_eq             ~> sup_fun_eq
  1844     meet_set_eq             ~> inf_set_eq
  1845     join_set_eq             ~> sup_set_eq
  1846     meet1_iff               ~> inf1_iff
  1847     meet2_iff               ~> inf2_iff
  1848     meet1I                  ~> inf1I
  1849     meet2I                  ~> inf2I
  1850     meet1D1                 ~> inf1D1
  1851     meet2D1                 ~> inf2D1
  1852     meet1D2                 ~> inf1D2
  1853     meet2D2                 ~> inf2D2
  1854     meet1E                  ~> inf1E
  1855     meet2E                  ~> inf2E
  1856     join1_iff               ~> sup1_iff
  1857     join2_iff               ~> sup2_iff
  1858     join1I1                 ~> sup1I1
  1859     join2I1                 ~> sup2I1
  1860     join1I1                 ~> sup1I1
  1861     join2I2                 ~> sup1I2
  1862     join1CI                 ~> sup1CI
  1863     join2CI                 ~> sup2CI
  1864     join1E                  ~> sup1E
  1865     join2E                  ~> sup2E
  1866 
  1867     is_meet_Meet            ~> is_meet_Inf
  1868     Meet_bool_def           ~> Inf_bool_def
  1869     Meet_fun_def            ~> Inf_fun_def
  1870     Meet_greatest           ~> Inf_greatest
  1871     Meet_lower              ~> Inf_lower
  1872     Meet_set_def            ~> Inf_set_def
  1873 
  1874     Sup_def                 ~> Sup_Inf
  1875     Sup_bool_eq             ~> Sup_bool_def
  1876     Sup_fun_eq              ~> Sup_fun_def
  1877     Sup_set_eq              ~> Sup_set_def
  1878 
  1879     listsp_meetI            ~> listsp_infI
  1880     listsp_meet_eq          ~> listsp_inf_eq
  1881 
  1882     meet_min                ~> inf_min
  1883     join_max                ~> sup_max
  1884 
  1885 * Added syntactic class "size"; overloaded constant "size" now has
  1886 type "'a::size ==> bool"
  1887 
  1888 * Internal reorganisation of `size' of datatypes: size theorems
  1889 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1890 simplification rules by default!); theorems "prod.size" now named
  1891 "*.size".
  1892 
  1893 * Class "div" now inherits from class "times" rather than "type".
  1894 INCOMPATIBILITY.
  1895 
  1896 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1897 Linorder etc.  have disappeared; operations defined in terms of
  1898 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1899 
  1900 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1901 
  1902 * HOL-Word: New extensive library and type for generic, fixed size
  1903 machine words, with arithemtic, bit-wise, shifting and rotating
  1904 operations, reflection into int, nat, and bool lists, automation for
  1905 linear arithmetic (by automatic reflection into nat or int), including
  1906 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1907 arithmetic type classes, supporting automatic simplification of
  1908 numerals on all operations.
  1909 
  1910 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1911 
  1912 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1913 
  1914 * Code generator library theories:
  1915   - Code_Integer represents HOL integers by big integer literals in target
  1916     languages.
  1917   - Code_Char represents HOL characters by character literals in target
  1918     languages.
  1919   - Code_Char_chr like Code_Char, but also offers treatment of character
  1920     codes; includes Code_Integer.
  1921   - Executable_Set allows to generate code for finite sets using lists.
  1922   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1923     denominator).
  1924   - Executable_Real implements a subset of real numbers, namly those
  1925     representable by rational numbers.
  1926   - Efficient_Nat implements natural numbers by integers, which in general will
  1927     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1928     includes Code_Integer.
  1929   - Code_Index provides an additional datatype index which is mapped to
  1930     target-language built-in integers.
  1931   - Code_Message provides an additional datatype message_string which is isomorphic to
  1932     strings; messages are mapped to target-language strings.
  1933 
  1934 * New package for inductive predicates
  1935 
  1936   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1937 
  1938     inductive
  1939       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1940       for z_1 :: U_1 and ... and z_n :: U_m
  1941     where
  1942       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1943     | ...
  1944 
  1945   with full support for type-inference, rather than
  1946 
  1947     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1948 
  1949     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1950     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1951 
  1952     inductive "s z_1 ... z_m"
  1953     intros
  1954       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1955       ...
  1956 
  1957   For backward compatibility, there is a wrapper allowing inductive
  1958   sets to be defined with the new package via
  1959 
  1960     inductive_set
  1961       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1962       for z_1 :: U_1 and ... and z_n :: U_m
  1963     where
  1964       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1965     | ...
  1966 
  1967   or
  1968 
  1969     inductive_set
  1970       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1971       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1972       for z_1 :: U_1 and ... and z_n :: U_m
  1973     where
  1974       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1975     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1976     | ...
  1977 
  1978   if the additional syntax "p ..." is required.
  1979 
  1980   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1981   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1982 
  1983   INCOMPATIBILITIES:
  1984 
  1985   - Since declaration and definition of inductive sets or predicates
  1986     is no longer separated, abbreviations involving the newly
  1987     introduced sets or predicates must be specified together with the
  1988     introduction rules after the 'where' keyword (see above), rather
  1989     than before the actual inductive definition.
  1990 
  1991   - The variables in induction and elimination rules are now
  1992     quantified in the order of their occurrence in the introduction
  1993     rules, rather than in alphabetical order. Since this may break
  1994     some proofs, these proofs either have to be repaired, e.g. by
  1995     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1996     statements of the form
  1997 
  1998       case (rule_i a_i_1 ... a_i_{k_i})
  1999 
  2000     or the old order of quantification has to be restored by explicitly adding
  2001     meta-level quantifiers in the introduction rules, i.e.
  2002 
  2003       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2004 
  2005   - The format of the elimination rules is now
  2006 
  2007       p z_1 ... z_m x_1 ... x_n ==>
  2008         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2009         ==> ... ==> P
  2010 
  2011     for predicates and
  2012 
  2013       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2014         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2015         ==> ... ==> P
  2016 
  2017     for sets rather than
  2018 
  2019       x : s z_1 ... z_m ==>
  2020         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2021         ==> ... ==> P
  2022 
  2023     This may require terms in goals to be expanded to n-tuples
  2024     (e.g. using case_tac or simplification with the split_paired_all
  2025     rule) before the above elimination rule is applicable.
  2026 
  2027   - The elimination or case analysis rules for (mutually) inductive
  2028     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2029     list of rules "p_1_..._p_k.elims" is no longer available.
  2030 
  2031 * New package "function"/"fun" for general recursive functions,
  2032 supporting mutual and nested recursion, definitions in local contexts,
  2033 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2034 for small examples, and the separate tutorial on the function
  2035 package. The old recdef "package" is still available as before, but
  2036 users are encouraged to use the new package.
  2037 
  2038 * Method "lexicographic_order" automatically synthesizes termination
  2039 relations as lexicographic combinations of size measures. 
  2040 
  2041 * Case-expressions allow arbitrary constructor-patterns (including
  2042 "_") and take their order into account, like in functional
  2043 programming.  Internally, this is translated into nested
  2044 case-expressions; missing cases are added and mapped to the predefined
  2045 constant "undefined". In complicated cases printing may no longer show
  2046 the original input but the internal form. Lambda-abstractions allow
  2047 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2048 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2049 variable.
  2050 
  2051 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2052 is an abbreviation for "of_nat :: nat => int". The simplification
  2053 rules for "of_nat" have been changed to work like "int" did
  2054 previously.  Potential INCOMPATIBILITY:
  2055   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2056   - of_nat_diff and of_nat_mult are no longer default simp rules
  2057 
  2058 * Method "algebra" solves polynomial equations over (semi)rings using
  2059 Groebner bases. The (semi)ring structure is defined by locales and the
  2060 tool setup depends on that generic context. Installing the method for
  2061 a specific type involves instantiating the locale and possibly adding
  2062 declarations for computation on the coefficients.  The method is
  2063 already instantiated for natural numbers and for the axiomatic class
  2064 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2065 CALCULEMUS 2007 for the general principles underlying this
  2066 architecture of context-aware proof-tools.
  2067 
  2068 * Method "ferrack" implements quantifier elimination over
  2069 special-purpose dense linear orders using locales (analogous to
  2070 "algebra"). The method is already installed for class
  2071 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2072 rat, etc.
  2073 
  2074 * Former constant "List.op @" now named "List.append".  Use ML
  2075 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2076 circumvent possible incompatibilities when working on ML level.
  2077 
  2078 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2079 
  2080 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2081 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2082 
  2083 * New syntax for Haskell-like list comprehension (input only), eg.
  2084 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2085 
  2086 * The special syntax for function "filter" has changed from [x :
  2087 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2088 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2089 
  2090 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2091 defined on nat only, as an abbreviation for [a..<Suc b]
  2092 INCOMPATIBILITY.
  2093 
  2094 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2095 
  2096 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2097 
  2098 * New lemma collection field_simps (an extension of ring_simps) for
  2099 manipulating (in)equations involving division. Multiplies with all
  2100 denominators that can be proved to be non-zero (in equations) or
  2101 positive/negative (in inequations).
  2102 
  2103 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2104 have been improved and renamed to ring_simps, group_simps and
  2105 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2106 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2107 
  2108 * Theory Library/Commutative_Ring: switched from recdef to function
  2109 package; constants add, mul, pow now curried.  Infix syntax for
  2110 algebraic operations.
  2111 
  2112 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2113 INCOMPATIBILITY.
  2114 
  2115 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2116 INCOMPATIBILITY.
  2117 
  2118 * HOL/records: generalised field-update to take a function on the
  2119 field rather than the new value: r(|A := x|) is translated to A_update
  2120 (K x) r The K-combinator that is internally used is called K_record.
  2121 INCOMPATIBILITY: Usage of the plain update functions has to be
  2122 adapted.
  2123  
  2124 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2125 * x = 0, which are required for a semiring.  Richer structures do not
  2126 inherit from semiring_0 anymore, because this property is a theorem
  2127 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2128 there is more to prove, but this is mostly trivial.
  2129 
  2130 * Class "recpower" is generalized to arbitrary monoids, not just
  2131 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2132 commutativity or semiring properties additionally.
  2133 
  2134 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2135 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2136 better use 'abbreviation'.
  2137 
  2138 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2139 
  2140 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2141 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2142 significant changes for setting up numeral syntax for types:
  2143   - New constants Numeral.pred and Numeral.succ instead
  2144       of former Numeral.bin_pred and Numeral.bin_succ.
  2145   - Use integer operations instead of bin_add, bin_mult and so on.
  2146   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2147   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2148 
  2149 See src/HOL/Integ/IntArith.thy for an example setup.
  2150 
  2151 * Command 'normal_form' computes the normal form of a term that may
  2152 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2153 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2154 heavy-duty computations because the functions are compiled to ML
  2155 first.  Correspondingly, a method "normalization" is provided.  See
  2156 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2157 
  2158 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2159 25 like -->); output depends on the "iff" print_mode, the default is
  2160 "A = B" (with priority 50).
  2161 
  2162 * Relations less (<) and less_eq (<=) are also available on type bool.
  2163 Modified syntax to disallow nesting without explicit parentheses,
  2164 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2165 INCOMPATIBILITY.
  2166 
  2167 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2168 
  2169 * Relation composition operator "op O" now has precedence 75 and binds
  2170 stronger than union and intersection. INCOMPATIBILITY.
  2171 
  2172 * The old set interval syntax "{m..n(}" (and relatives) has been
  2173 removed.  Use "{m..<n}" (and relatives) instead.
  2174 
  2175 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2176 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2177 ``declare [[simproc del: neq]]''.
  2178 
  2179 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2180 True/False.
  2181 
  2182 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2183 
  2184 * Theorem setsum_mult renamed to setsum_right_distrib.
  2185 
  2186 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2187 ``rule'' method.
  2188 
  2189 * Reimplemented methods "sat" and "satx", with several improvements:
  2190 goals no longer need to be stated as "<prems> ==> False", equivalences
  2191 (i.e. "=" on type bool) are handled, variable names of the form
  2192 "lit_<n>" are no longer reserved, significant speedup.
  2193 
  2194 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2195 zChaff is still supported as well.
  2196 
  2197 * 'inductive' and 'datatype': provide projections of mutual rules,
  2198 bundled as foo_bar.inducts;
  2199 
  2200 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2201 Library.
  2202 
  2203 * Library: moved theory Accessible_Part to main HOL.
  2204 
  2205 * Library: added theory Coinductive_List of potentially infinite lists
  2206 as greatest fixed-point.
  2207 
  2208 * Library: added theory AssocList which implements (finite) maps as
  2209 association lists.
  2210 
  2211 * Method "evaluation" solves goals (i.e. a boolean expression)
  2212 efficiently by compiling it to ML.  The goal is "proved" (via an
  2213 oracle) if it evaluates to True.
  2214 
  2215 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2216 also when invoked by the simplifier.  This results in the Simplifier
  2217 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2218 Configuration option fast_arith_split_limit=0 recovers the old
  2219 behavior.
  2220 
  2221 * Support for hex (0x20) and binary (0b1001) numerals.
  2222 
  2223 * New method: reify eqs (t), where eqs are equations for an
  2224 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2225 parameter, computes a term s::'b and a list xs::'a list and proves the
  2226 theorem I xs s = t. This is also known as reification or quoting. The
  2227 resulting theorem is applied to the subgoal to substitute t with I xs
  2228 s.  If t is omitted, the subgoal itself is reified.
  2229 
  2230 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2231 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2232 where f is supposed to be a computable function (in the sense of code
  2233 generattion). The method uses reify to compute s and xs as above then
  2234 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2235 r and finally gets the theorem t = r, which is again applied to the
  2236 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2237 
  2238 * Reflection: Automatic reification now handels binding, an example is
  2239 available in src/HOL/ex/ReflectionEx.thy
  2240 
  2241 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2242 command 'statespace' that is similar to 'record', but introduces an
  2243 abstract specification based on the locale infrastructure instead of
  2244 HOL types.  This leads to extra flexibility in composing state spaces,
  2245 in particular multiple inheritance and renaming of components.
  2246 
  2247 
  2248 *** HOL-Complex ***
  2249 
  2250 * Hyperreal: Functions root and sqrt are now defined on negative real
  2251 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2252 Nonnegativity side conditions have been removed from many lemmas, so
  2253 that more subgoals may now be solved by simplification; potential
  2254 INCOMPATIBILITY.
  2255 
  2256 * Real: new type classes formalize real normed vector spaces and
  2257 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2258 and norm :: 'a => real.
  2259 
  2260 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2261 reals into other types. The overloaded constant Reals :: 'a set is now
  2262 defined as range of_real; potential INCOMPATIBILITY.
  2263 
  2264 * Real: proper support for ML code generation, including 'quickcheck'.
  2265 Reals are implemented as arbitrary precision rationals.
  2266 
  2267 * Hyperreal: Several constants that previously worked only for the
  2268 reals have been generalized, so they now work over arbitrary vector
  2269 spaces. Type annotations may need to be added in some cases; potential
  2270 INCOMPATIBILITY.
  2271 
  2272   Infinitesimal  :: ('a::real_normed_vector) star set
  2273   HFinite        :: ('a::real_normed_vector) star set
  2274   HInfinite      :: ('a::real_normed_vector) star set
  2275   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2276   monad          :: ('a::real_normed_vector) star => 'a star set
  2277   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2278   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2279   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2280   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2281   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2282   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2283   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2284   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2285   sgn            :: 'a::real_normed_vector => 'a
  2286   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2287 
  2288 * Complex: Some complex-specific constants are now abbreviations for
  2289 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2290 hnorm.  Other constants have been entirely removed in favor of the
  2291 polymorphic versions (INCOMPATIBILITY):
  2292 
  2293   approx        <-- capprox
  2294   HFinite       <-- CFinite
  2295   HInfinite     <-- CInfinite
  2296   Infinitesimal <-- CInfinitesimal
  2297   monad         <-- cmonad
  2298   galaxy        <-- cgalaxy
  2299   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2300   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2301   (ns)deriv     <-- (ns)cderiv
  2302 
  2303 
  2304 *** HOL-Algebra ***
  2305 
  2306 * Formalisation of ideals and the quotient construction over rings.
  2307 
  2308 * Order and lattice theory no longer based on records.
  2309 INCOMPATIBILITY.
  2310 
  2311 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2312 greatest_closed.  INCOMPATIBILITY.
  2313 
  2314 * Method algebra is now set up via an attribute.  For examples see
  2315 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2316 of algebraic structures.
  2317 
  2318 * Renamed theory CRing to Ring.
  2319 
  2320 
  2321 *** HOL-Nominal ***
  2322 
  2323 * Substantial, yet incomplete support for nominal datatypes (binding
  2324 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2325 src/HOL/Nominal/Examples.  Prospective users should consult
  2326 http://isabelle.in.tum.de/nominal/
  2327 
  2328 
  2329 *** ML ***
  2330 
  2331 * ML basics: just one true type int, which coincides with IntInf.int
  2332 (even on SML/NJ).
  2333 
  2334 * ML within Isar: antiquotations allow to embed statically-checked
  2335 formal entities in the source, referring to the context available at
  2336 compile-time.  For example:
  2337 
  2338 ML {* @{sort "{zero,one}"} *}
  2339 ML {* @{typ "'a => 'b"} *}
  2340 ML {* @{term "%x. x"} *}
  2341 ML {* @{prop "x == y"} *}
  2342 ML {* @{ctyp "'a => 'b"} *}
  2343 ML {* @{cterm "%x. x"} *}
  2344 ML {* @{cprop "x == y"} *}
  2345 ML {* @{thm asm_rl} *}
  2346 ML {* @{thms asm_rl} *}
  2347 ML {* @{type_name c} *}
  2348 ML {* @{type_syntax c} *}
  2349 ML {* @{const_name c} *}
  2350 ML {* @{const_syntax c} *}
  2351 ML {* @{context} *}
  2352 ML {* @{theory} *}
  2353 ML {* @{theory Pure} *}
  2354 ML {* @{theory_ref} *}
  2355 ML {* @{theory_ref Pure} *}
  2356 ML {* @{simpset} *}
  2357 ML {* @{claset} *}
  2358 ML {* @{clasimpset} *}
  2359 
  2360 The same works for sources being ``used'' within an Isar context.
  2361 
  2362 * ML in Isar: improved error reporting; extra verbosity with
  2363 ML_Context.trace enabled.
  2364 
  2365 * Pure/General/table.ML: the join operations now works via exceptions
  2366 DUP/SAME instead of type option. This is simpler in simple cases, and
  2367 admits slightly more efficient complex applications.
  2368 
  2369 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2370 use Context.generic instead of just theory.
  2371 
  2372 * Pure: datatype Context.generic joins theory/Proof.context and
  2373 provides some facilities for code that works in either kind of
  2374 context, notably GenericDataFun for uniform theory and proof data.
  2375 
  2376 * Pure: simplified internal attribute type, which is now always
  2377 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2378 local (Proof.context) attributes have been discontinued, while
  2379 minimizing code duplication. Thm.rule_attribute and
  2380 Thm.declaration_attribute build canonical attributes; see also structure
  2381 Context for further operations on Context.generic, notably
  2382 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2383 declarations and definitions.
  2384 
  2385 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2386 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2387 init only required for impure data. INCOMPATIBILITY: empty really need
  2388 to be empty (no dependencies on theory content!)
  2389 
  2390 * Pure/kernel: consts certification ignores sort constraints given in
  2391 signature declarations. (This information is not relevant to the
  2392 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2393 potential INCOMPATIBILITY.
  2394 
  2395 * Pure: axiomatic type classes are now purely definitional, with
  2396 explicit proofs of class axioms and super class relations performed
  2397 internally. See Pure/axclass.ML for the main internal interfaces --
  2398 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2399 AxClass.axiomatize_class/classrel/arity supersede
  2400 Sign.add_classes/classrel/arities.
  2401 
  2402 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2403 global/local versions on theory vs. Proof.context have been
  2404 discontinued; Attrib.syntax and Method.syntax have been adapted
  2405 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2406 attributes, methods, etc.
  2407 
  2408 * Pure: several functions of signature "... -> theory -> theory * ..."
  2409 have been reoriented to "... -> theory -> ... * theory" in order to
  2410 allow natural usage in combination with the ||>, ||>>, |-> and
  2411 fold_map combinators.
  2412 
  2413 * Pure: official theorem names (closed derivations) and additional
  2414 comments (tags) are now strictly separate.  Name hints -- which are
  2415 maintained as tags -- may be attached any time without affecting the
  2416 derivation.
  2417 
  2418 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2419 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2420 achieve the old behaviour.
  2421 
  2422 * Pure: the "Goal" constant is now called "prop", supporting a
  2423 slightly more general idea of ``protecting'' meta-level rule
  2424 statements.
  2425 
  2426 * Pure: Logic.(un)varify only works in a global context, which is now
  2427 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2428 Logic.legacy_(un)varify as temporary workaround.
  2429 
  2430 * Pure: structure Name provides scalable operations for generating
  2431 internal variable names, notably Name.variants etc.  This replaces
  2432 some popular functions from term.ML:
  2433 
  2434   Term.variant		->  Name.variant
  2435   Term.variantlist	->  Name.variant_list
  2436   Term.invent_names	->  Name.invent_list
  2437 
  2438 Note that low-level renaming rarely occurs in new code -- operations
  2439 from structure Variable are used instead (see below).
  2440 
  2441 * Pure: structure Variable provides fundamental operations for proper
  2442 treatment of fixed/schematic variables in a context.  For example,
  2443 Variable.import introduces fixes for schematics of given facts and
  2444 Variable.export reverses the effect (up to renaming) -- this replaces
  2445 various freeze_thaw operations.
  2446 
  2447 * Pure: structure Goal provides simple interfaces for
  2448 init/conclude/finish and tactical prove operations (replacing former
  2449 Tactic.prove).  Goal.prove is the canonical way to prove results
  2450 within a given context; Goal.prove_global is a degraded version for
  2451 theory level goals, including a global Drule.standard.  Note that
  2452 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2453 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2454 in a locale context).
  2455 
  2456 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2457 and type checking (Syntax.check_term etc.), with common combinations
  2458 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2459 which are considered legacy and await removal.
  2460 
  2461 * Pure/Syntax: generic interfaces for type unchecking
  2462 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2463 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2464 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2465 available for convenience, but refer to the very same operations using
  2466 a mere theory instead of a full context.
  2467 
  2468 * Isar: simplified treatment of user-level errors, using exception
  2469 ERROR of string uniformly.  Function error now merely raises ERROR,
  2470 without any side effect on output channels.  The Isar toplevel takes
  2471 care of proper display of ERROR exceptions.  ML code may use plain
  2472 handle/can/try; cat_error may be used to concatenate errors like this:
  2473 
  2474   ... handle ERROR msg => cat_error msg "..."
  2475 
  2476 Toplevel ML code (run directly or through the Isar toplevel) may be
  2477 embedded into the Isar toplevel with exception display/debug like
  2478 this:
  2479 
  2480   Isar.toplevel (fn () => ...)
  2481 
  2482 INCOMPATIBILITY, removed special transform_error facilities, removed
  2483 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2484 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2485 -- use plain ERROR instead.
  2486 
  2487 * Isar: theory setup now has type (theory -> theory), instead of a
  2488 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2489 
  2490 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2491 ProofContext.debug/verbose flags.
  2492 
  2493 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2494 theory before entering a proof state.  Transactions now always see a
  2495 quasi-functional intermediate checkpoint, both in interactive and
  2496 batch mode.
  2497 
  2498 * Isar: simplified interfaces for outer syntax.  Renamed
  2499 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2500 OuterSyntax.add_parsers -- this functionality is now included in
  2501 OuterSyntax.command etc.  INCOMPATIBILITY.
  2502 
  2503 * Simplifier: the simpset of a running simplification process now
  2504 contains a proof context (cf. Simplifier.the_context), which is the
  2505 very context that the initial simpset has been retrieved from (by
  2506 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2507 (solver, looper etc.) may depend on arbitrary proof data.
  2508 
  2509 * Simplifier.inherit_context inherits the proof context (plus the
  2510 local bounds) of the current simplification process; any simproc
  2511 etc. that calls the Simplifier recursively should do this!  Removed
  2512 former Simplifier.inherit_bounds, which is already included here --
  2513 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2514 specify an explicit context using Simplifier.context/theory_context.
  2515 
  2516 * Simplifier/Classical Reasoner: more abstract interfaces
  2517 change_simpset/claset for modifying the simpset/claset reference of a
  2518 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2519 INCOMPATIBILITY.
  2520 
  2521 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2522 "Trueprop" etc.
  2523 
  2524 
  2525 *** System ***
  2526 
  2527 * settings: the default heap location within ISABELLE_HOME_USER now
  2528 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2529 Isabelle installations.
  2530 
  2531 * isabelle-process: option -S (secure mode) disables some critical
  2532 operations, notably runtime compilation and evaluation of ML source
  2533 code.
  2534 
  2535 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2536 
  2537 * Support for parallel execution, using native multicore support of
  2538 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2539 independent theories, according to the given theory header
  2540 specifications. The maximum number of worker threads is specified via
  2541 usedir option -M or the "max-threads" setting in Proof General. A
  2542 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2543 to 6 on a 8-core machine.  User-code needs to observe certain
  2544 guidelines for thread-safe programming, see appendix A in the Isar
  2545 Implementation manual.
  2546 
  2547 
  2548 
  2549 New in Isabelle2005 (October 2005)
  2550 ----------------------------------
  2551 
  2552 *** General ***
  2553 
  2554 * Theory headers: the new header syntax for Isar theories is
  2555 
  2556   theory <name>
  2557   imports <theory1> ... <theoryN>
  2558   uses <file1> ... <fileM>
  2559   begin
  2560 
  2561 where the 'uses' part is optional.  The previous syntax
  2562 
  2563   theory <name> = <theory1> + ... + <theoryN>:
  2564 
  2565 will disappear in the next release.  Use isatool fixheaders to convert
  2566 existing theory files.  Note that there is no change in ancient
  2567 non-Isar theories now, but these will disappear soon.
  2568 
  2569 * Theory loader: parent theories can now also be referred to via
  2570 relative and absolute paths.
  2571 
  2572 * Command 'find_theorems' searches for a list of criteria instead of a
  2573 list of constants. Known criteria are: intro, elim, dest, name:string,
  2574 simp:term, and any term. Criteria can be preceded by '-' to select
  2575 theorems that do not match. Intro, elim, dest select theorems that
  2576 match the current goal, name:s selects theorems whose fully qualified
  2577 name contain s, and simp:term selects all simplification rules whose
  2578 lhs match term.  Any other term is interpreted as pattern and selects
  2579 all theorems matching the pattern. Available in ProofGeneral under
  2580 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2581 
  2582   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2583 
  2584 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2585 matching the current goal as introduction rule and not having "HOL."
  2586 in their name (i.e. not being defined in theory HOL).
  2587 
  2588 * Command 'thms_containing' has been discontinued in favour of
  2589 'find_theorems'; INCOMPATIBILITY.
  2590 
  2591 * Communication with Proof General is now 8bit clean, which means that
  2592 Unicode text in UTF-8 encoding may be used within theory texts (both
  2593 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2594 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2595 
  2596   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2597   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2598 
  2599 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2600 Classical Reasoner.  Typical big applications run around 2 times
  2601 faster.
  2602 
  2603 
  2604 *** Document preparation ***
  2605 
  2606 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2607 of raw sources.  Only those symbols that do not require additional
  2608 LaTeX packages (depending on comments in isabellesym.sty) are
  2609 displayed properly, everything else is left verbatim.  isatool display
  2610 and isatool print are used as front ends (these are subject to the
  2611 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2612 
  2613 * Command tags control specific markup of certain regions of text,
  2614 notably folding and hiding.  Predefined tags include "theory" (for
  2615 theory begin and end), "proof" for proof commands, and "ML" for
  2616 commands involving ML code; the additional tags "visible" and
  2617 "invisible" are unused by default.  Users may give explicit tag
  2618 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2619 interpretation of tags is determined by the LaTeX job during document
  2620 preparation: see option -V of isatool usedir, or options -n and -t of
  2621 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2622 \isadroptag.
  2623 
  2624 Several document versions may be produced at the same time via isatool
  2625 usedir (the generated index.html will link all of them).  Typical
  2626 specifications include ''-V document=theory,proof,ML'' to present
  2627 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2628 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2629 these parts without any formal replacement text.  The Isabelle site
  2630 default settings produce ''document'' and ''outline'' versions as
  2631 specified above.
  2632 
  2633 * Several new antiquotations:
  2634 
  2635   @{term_type term} prints a term with its type annotated;
  2636 
  2637   @{typeof term} prints the type of a term;
  2638 
  2639   @{const const} is the same as @{term const}, but checks that the
  2640   argument is a known logical constant;
  2641 
  2642   @{term_style style term} and @{thm_style style thm} print a term or
  2643   theorem applying a "style" to it
  2644 
  2645   @{ML text}
  2646 
  2647 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2648 definitions, equations, inequations etc., 'concl' printing only the
  2649 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2650 to print the specified premise.  TermStyle.add_style provides an ML
  2651 interface for introducing further styles.  See also the "LaTeX Sugar"
  2652 document practical applications.  The ML antiquotation prints
  2653 type-checked ML expressions verbatim.
  2654 
  2655 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2656 and 'text' support optional locale specification '(in loc)', which
  2657 specifies the default context for interpreting antiquotations.  For
  2658 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2659 
  2660 * Option 'locale=NAME' of antiquotations specifies an alternative
  2661 context interpreting the subsequent argument.  For example: @{thm
  2662 [locale=lattice] inf_assoc}.
  2663 
  2664 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2665 a proof context.
  2666 
  2667 * Proper output of antiquotations for theory commands involving a
  2668 proof context (such as 'locale' or 'theorem (in loc) ...').
  2669 
  2670 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2671 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2672 
  2673 * isatool usedir: new option -C (default true) controls whether option
  2674 -D should include a copy of the original document directory; -C false
  2675 prevents unwanted effects such as copying of administrative CVS data.
  2676 
  2677 
  2678 *** Pure ***
  2679 
  2680 * Considerably improved version of 'constdefs' command.  Now performs
  2681 automatic type-inference of declared constants; additional support for
  2682 local structure declarations (cf. locales and HOL records), see also
  2683 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2684 sequential dependencies of definitions within a single 'constdefs'
  2685 section; moreover, the declared name needs to be an identifier.  If
  2686 all fails, consider to fall back on 'consts' and 'defs' separately.
  2687 
  2688 * Improved indexed syntax and implicit structures.  First of all,
  2689 indexed syntax provides a notational device for subscripted
  2690 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2691 expressions.  Secondly, in a local context with structure
  2692 declarations, number indexes \<^sub>n or the empty index (default
  2693 number 1) refer to a certain fixed variable implicitly; option
  2694 show_structs controls printing of implicit structures.  Typical
  2695 applications of these concepts involve record types and locales.
  2696 
  2697 * New command 'no_syntax' removes grammar declarations (and
  2698 translations) resulting from the given syntax specification, which is
  2699 interpreted in the same manner as for the 'syntax' command.
  2700 
  2701 * 'Advanced' translation functions (parse_translation etc.) may depend
  2702 on the signature of the theory context being presently used for
  2703 parsing/printing, see also isar-ref manual.
  2704 
  2705 * Improved 'oracle' command provides a type-safe interface to turn an
  2706 ML expression of type theory -> T -> term into a primitive rule of
  2707 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2708 is already included here); see also FOL/ex/IffExample.thy;
  2709 INCOMPATIBILITY.
  2710 
  2711 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2712 before); "cI" is no longer bound, use "c.intro" instead.
  2713 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2714 axclasses vs. locales.
  2715 
  2716 * Improved internal renaming of symbolic identifiers -- attach primes
  2717 instead of base 26 numbers.
  2718 
  2719 * New flag show_question_marks controls printing of leading question
  2720 marks in schematic variable names.
  2721 
  2722 * In schematic variable names, *any* symbol following \<^isub> or
  2723 \<^isup> is now treated as part of the base name.  For example, the
  2724 following works without printing of awkward ".0" indexes:
  2725 
  2726   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2727     by simp
  2728 
  2729 * Inner syntax includes (*(*nested*) comments*).
  2730 
  2731 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2732 annotations as "(00...)".
  2733 
  2734 * Clear separation of logical types and nonterminals, where the latter
  2735 may only occur in 'syntax' specifications or type abbreviations.
  2736 Before that distinction was only partially implemented via type class
  2737 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2738 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2739 exotic syntax specifications may require further adaption
  2740 (e.g. Cube/Cube.thy).
  2741 
  2742 * Removed obsolete type class "logic", use the top sort {} instead.
  2743 Note that non-logical types should be declared as 'nonterminals'
  2744 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2745 specifications.
  2746 
  2747 * Attributes 'induct' and 'cases': type or set names may now be
  2748 locally fixed variables as well.
  2749 
  2750 * Simplifier: can now control the depth to which conditional rewriting
  2751 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2752 Limit.
  2753 
  2754 * Simplifier: simplification procedures may now take the current
  2755 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2756 interface), which is very useful for calling the Simplifier
  2757 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2758 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2759 low-level mk_simproc no longer applies Logic.varify internally, to
  2760 allow for use in a context of fixed variables.
  2761 
  2762 * thin_tac now works even if the assumption being deleted contains !!
  2763 or ==>.  More generally, erule now works even if the major premise of
  2764 the elimination rule contains !! or ==>.
  2765 
  2766 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2767 
  2768 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2769 from Pure, which contains all common declarations already.  Both
  2770 theories are defined via plain Isabelle/Isar .thy files.
  2771 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2772 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2773 use isatool fixcpure to adapt your theory and ML sources.
  2774 
  2775 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2776 selections of theorems in named facts via index ranges.
  2777 
  2778 * 'print_theorems': in theory mode, really print the difference
  2779 wrt. the last state (works for interactive theory development only),
  2780 in proof mode print all local facts (cf. 'print_facts');
  2781 
  2782 * 'hide': option '(open)' hides only base names.
  2783 
  2784 * More efficient treatment of intermediate checkpoints in interactive
  2785 theory development.
  2786 
  2787 * Code generator is now invoked via code_module (incremental code
  2788 generation) and code_library (modular code generation, ML structures
  2789 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2790 must be quoted when used as identifiers.
  2791 
  2792 * New 'value' command for reading, evaluating and printing terms using
  2793 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2794 quoted when used as identifier.
  2795 
  2796 
  2797 *** Locales ***
  2798 
  2799 * New commands for the interpretation of locale expressions in
  2800 theories (1), locales (2) and proof contexts (3).  These generate
  2801 proof obligations from the expression specification.  After the
  2802 obligations have been discharged, theorems of the expression are added
  2803 to the theory, target locale or proof context.  The synopsis of the
  2804 commands is a follows:
  2805 
  2806   (1) interpretation expr inst
  2807   (2) interpretation target < expr
  2808   (3) interpret expr inst
  2809 
  2810 Interpretation in theories and proof contexts require a parameter
  2811 instantiation of terms from the current context.  This is applied to
  2812 specifications and theorems of the interpreted expression.
  2813 Interpretation in locales only permits parameter renaming through the
  2814 locale expression.  Interpretation is smart in that interpretations
  2815 that are active already do not occur in proof obligations, neither are
  2816 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2817 inspect active interpretations of a particular locale.  For details,
  2818 see the Isar Reference manual.  Examples can be found in
  2819 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2820 
  2821 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2822 'interpret' instead.
  2823 
  2824 * New context element 'constrains' for adding type constraints to
  2825 parameters.
  2826 
  2827 * Context expressions: renaming of parameters with syntax
  2828 redeclaration.
  2829 
  2830 * Locale declaration: 'includes' disallowed.
  2831 
  2832 * Proper static binding of attribute syntax -- i.e. types / terms /
  2833 facts mentioned as arguments are always those of the locale definition
  2834 context, independently of the context of later invocations.  Moreover,
  2835 locale operations (renaming and type / term instantiation) are applied
  2836 to attribute arguments as expected.
  2837 
  2838 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2839 actual attributes; rare situations may require Attrib.attribute to
  2840 embed those attributes into Attrib.src that lack concrete syntax.
  2841 Attribute implementations need to cooperate properly with the static
  2842 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2843 Attrib.XXX_thm etc. already do the right thing without further
  2844 intervention.  Only unusual applications -- such as "where" or "of"
  2845 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2846 on the context and the facts involved -- may have to assign parsed
  2847 values to argument tokens explicitly.
  2848 
  2849 * Changed parameter management in theorem generation for long goal
  2850 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2851 theorem statement in rare situations.
  2852 
  2853 * Locale inspection command 'print_locale' omits notes elements.  Use
  2854 'print_locale!' to have them included in the output.
  2855 
  2856 
  2857 *** Provers ***
  2858 
  2859 * Provers/hypsubst.ML: improved version of the subst method, for
  2860 single-step rewriting: it now works in bound variable contexts. New is
  2861 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2862 rewrite a different subterm than the original subst method, which is
  2863 still available as 'simplesubst'.
  2864 
  2865 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2866 and quasi orders.
  2867 
  2868 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2869 reflexive-transitive closure of relations.
  2870 
  2871 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2872 limit (previously hard-coded with a value of 20) user-definable.
  2873 
  2874 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2875 is peformed already.  Object-logics merely need to finish their
  2876 initial simpset configuration as before.  INCOMPATIBILITY.
  2877 
  2878 
  2879 *** HOL ***
  2880 
  2881 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2882 
  2883   syntax (epsilon)
  2884     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2885 
  2886 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2887 and x-symbol; use option '-m epsilon' to get it actually printed.
  2888 Moreover, the mathematically important symbolic identifier \<epsilon>
  2889 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2890 
  2891 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2892 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2893 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2894 support corresponding Isar calculations.
  2895 
  2896 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2897 instead of ":".
  2898 
  2899 * theory SetInterval: changed the syntax for open intervals:
  2900 
  2901   Old       New
  2902   {..n(}    {..<n}
  2903   {)n..}    {n<..}
  2904   {m..n(}   {m..<n}
  2905   {)m..n}   {m<..n}
  2906   {)m..n(}  {m<..<n}
  2907 
  2908 The old syntax is still supported but will disappear in the next
  2909 release.  For conversion use the following Emacs search and replace
  2910 patterns (these are not perfect but work quite well):
  2911 
  2912   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2913   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2914 
  2915 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2916 equalities in commutative rings; method 'algebra' provides a generic
  2917 interface.
  2918 
  2919 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2920 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2921 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2922 be a tuple pattern.
  2923 
  2924 Some new syntax forms are available:
  2925 
  2926   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2927   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2928   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2929   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2930 
  2931 The latter form "\<Sum>x < k. e" used to be based on a separate
  2932 function "Summation", which has been discontinued.
  2933 
  2934 * theory Finite_Set: in structured induction proofs, the insert case
  2935 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2936 (insert F x)'.
  2937 
  2938 * The 'refute' command has been extended to support a much larger
  2939 fragment of HOL, including axiomatic type classes, constdefs and
  2940 typedefs, inductive datatypes and recursion.
  2941 
  2942 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2943 Requires zChaff with proof generation to be installed.  See
  2944 HOL/ex/SAT_Examples.thy for examples.
  2945 
  2946 * Datatype induction via method 'induct' now preserves the name of the
  2947 induction variable. For example, when proving P(xs::'a list) by
  2948 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2949 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2950 in unstructured proof scripts.
  2951 
  2952 * Reworked implementation of records.  Improved scalability for
  2953 records with many fields, avoiding performance problems for type
  2954 inference. Records are no longer composed of nested field types, but
  2955 of nested extension types. Therefore the record type only grows linear
  2956 in the number of extensions and not in the number of fields.  The
  2957 top-level (users) view on records is preserved.  Potential
  2958 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2959 old record representation. The type generated for a record is called
  2960 <record_name>_ext_type.
  2961 
  2962 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2963 proofs triggered by a record definition or a simproc (if
  2964 quick_and_dirty is enabled).  Definitions of large records can take
  2965 quite long.
  2966 
  2967 New simproc record_upd_simproc for simplification of multiple record
  2968 updates enabled by default.  Moreover, trivial updates are also
  2969 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2970 occasionally, since simplification is more powerful by default.
  2971 
  2972 * typedef: proper support for polymorphic sets, which contain extra
  2973 type-variables in the term.
  2974 
  2975 * Simplifier: automatically reasons about transitivity chains
  2976 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2977 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2978 old proofs break occasionally as simplification may now solve more
  2979 goals than previously.
  2980 
  2981 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2982 present.  Works for all partial orders (class "order"), in particular
  2983 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2984 just like y <= x.
  2985 
  2986 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2987 bound variable or a constant then the let is unfolded.  Otherwise
  2988 first a is simplified to b, and then f b is simplified to g. If
  2989 possible we abstract b from g arriving at "let x = b in h x",
  2990 otherwise we unfold the let and arrive at g.  The simproc can be
  2991 enabled/disabled by the reference use_let_simproc.  Potential
  2992 INCOMPATIBILITY since simplification is more powerful by default.
  2993 
  2994 * Classical reasoning: the meson method now accepts theorems as arguments.
  2995 
  2996 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2997 jobs to provide advice on the provability of subgoals.
  2998 
  2999 * Theory OrderedGroup and Ring_and_Field: various additions and
  3000 improvements to faciliate calculations involving equalities and
  3001 inequalities.
  3002 
  3003 The following theorems have been eliminated or modified
  3004 (INCOMPATIBILITY):
  3005 
  3006   abs_eq             now named abs_of_nonneg
  3007   abs_of_ge_0        now named abs_of_nonneg
  3008   abs_minus_eq       now named abs_of_nonpos
  3009   imp_abs_id         now named abs_of_nonneg
  3010   imp_abs_neg_id     now named abs_of_nonpos
  3011   mult_pos           now named mult_pos_pos
  3012   mult_pos_le        now named mult_nonneg_nonneg
  3013   mult_pos_neg_le    now named mult_nonneg_nonpos
  3014   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3015   mult_neg           now named mult_neg_neg
  3016   mult_neg_le        now named mult_nonpos_nonpos
  3017 
  3018 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3019      
  3020      zero_le_square
  3021      not_square_less_zero 
  3022 
  3023   The following lemmas have been deleted from Real/RealPow:
  3024   
  3025      realpow_zero_zero
  3026      realpow_two
  3027      realpow_less
  3028      zero_le_power
  3029      realpow_two_le
  3030      abs_realpow_two
  3031      realpow_two_abs     
  3032 
  3033 * Theory Parity: added rules for simplifying exponents.
  3034 
  3035 * Theory List:
  3036 
  3037 The following theorems have been eliminated or modified
  3038 (INCOMPATIBILITY):
  3039 
  3040   list_all_Nil       now named list_all.simps(1)
  3041   list_all_Cons      now named list_all.simps(2)
  3042   list_all_conv      now named list_all_iff
  3043   set_mem_eq         now named mem_iff
  3044 
  3045 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3046 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3047 
  3048 
  3049 *** HOL-Complex ***
  3050 
  3051 * Theory RealDef: better support for embedding natural numbers and
  3052 integers in the reals.
  3053 
  3054 The following theorems have been eliminated or modified
  3055 (INCOMPATIBILITY):
  3056 
  3057   exp_ge_add_one_self  now requires no hypotheses
  3058   real_of_int_add      reversed direction of equality (use [symmetric])
  3059   real_of_int_minus    reversed direction of equality (use [symmetric])
  3060   real_of_int_diff     reversed direction of equality (use [symmetric])
  3061   real_of_int_mult     reversed direction of equality (use [symmetric])
  3062 
  3063 * Theory RComplete: expanded support for floor and ceiling functions.
  3064 
  3065 * Theory Ln is new, with properties of the natural logarithm
  3066 
  3067 * Hyperreal: There is a new type constructor "star" for making
  3068 nonstandard types.  The old type names are now type synonyms:
  3069 
  3070   hypreal = real star
  3071   hypnat = nat star
  3072   hcomplex = complex star
  3073 
  3074 * Hyperreal: Many groups of similarly-defined constants have been
  3075 replaced by polymorphic versions (INCOMPATIBILITY):
  3076 
  3077   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3078 
  3079   starset      <-- starsetNat, starsetC
  3080   *s*          <-- *sNat*, *sc*
  3081   starset_n    <-- starsetNat_n, starsetC_n
  3082   *sn*         <-- *sNatn*, *scn*
  3083   InternalSets <-- InternalNatSets, InternalCSets
  3084 
  3085   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3086   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3087   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3088   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3089   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3090 
  3091 * Hyperreal: Many type-specific theorems have been removed in favor of
  3092 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3093 
  3094   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3095   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3096   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3097   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3098   right_minus <-- hypreal_add_minus
  3099   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3100   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3101   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3102   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3103   mult_1_right <-- hcomplex_mult_one_right
  3104   mult_zero_left <-- hcomplex_mult_zero_left
  3105   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3106   right_distrib <-- hypnat_add_mult_distrib2
  3107   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3108   right_inverse <-- hypreal_mult_inverse
  3109   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3110   order_refl <-- {hypreal,hypnat}_le_refl
  3111   order_trans <-- {hypreal,hypnat}_le_trans
  3112   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3113   order_less_le <-- {hypreal,hypnat}_less_le
  3114   linorder_linear <-- {hypreal,hypnat}_le_linear
  3115   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3116   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3117   add_nonneg_nonneg <-- hypreal_le_add_order
  3118 
  3119 * Hyperreal: Separate theorems having to do with type-specific
  3120 versions of constants have been merged into theorems that apply to the
  3121 new polymorphic constants (INCOMPATIBILITY):
  3122 
  3123   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3124   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3125   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3126   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3127   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3128   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3129   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3130   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3131   STAR_diff <-- {STAR,STARC}_diff
  3132   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3133     STARC_hcomplex_of_complex}_image_subset
  3134   starset_n_Un <-- starset{Nat,C}_n_Un
  3135   starset_n_Int <-- starset{Nat,C}_n_Int
  3136   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3137   starset_n_diff <-- starset{Nat,C}_n_diff
  3138   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3139   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3140   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3141   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3142   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3143   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3144   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3145   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3146   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3147   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3148   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3149   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3150   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3151   starfun_diff <-- starfun{C,RC,CR}_diff
  3152   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3153   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3154   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3155   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3156   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3157   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3158   starfun_Id <-- starfunC_Id
  3159   starfun_approx <-- starfun{Nat,CR}_approx
  3160   starfun_capprox <-- starfun{C,RC}_capprox
  3161   starfun_abs <-- starfunNat_rabs
  3162   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3163   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3164   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3165   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3166   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3167   starfun_add_approx <-- starfunCR_add_approx
  3168   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3169   starfun_divide <-- starfun{C,CR,RC}_divide
  3170   starfun_n <-- starfun{Nat,C}_n
  3171   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3172   starfun_n_add <-- starfun{Nat,C}_n_add
  3173   starfun_n_add_minus <-- starfunNat_n_add_minus
  3174   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3175   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3176   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3177 
  3178   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3179   star_n_minus <-- {hypreal,hcomplex}_minus
  3180   star_n_diff <-- {hypreal,hcomplex}_diff
  3181   star_n_mult <-- {hypreal,hcomplex}_mult
  3182   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3183   star_n_le <-- {hypreal,hypnat}_le
  3184   star_n_less <-- {hypreal,hypnat}_less
  3185   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3186   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3187   star_n_abs <-- hypreal_hrabs
  3188   star_n_divide <-- hcomplex_divide
  3189 
  3190   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3191   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3192   star_of_diff <-- hypreal_of_real_diff
  3193   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3194   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3195   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3196   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3197   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3198   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3199   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3200   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3201   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3202   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3203   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3204   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3205   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3206   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3207   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3208   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3209   star_of_power <-- hypreal_of_real_power
  3210   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3211 
  3212 * Hyperreal: new method "transfer" that implements the transfer
  3213 principle of nonstandard analysis. With a subgoal that mentions
  3214 nonstandard types like "'a star", the command "apply transfer"
  3215 replaces it with an equivalent one that mentions only standard types.
  3216 To be successful, all free variables must have standard types; non-
  3217 standard variables must have explicit universal quantifiers.
  3218 
  3219 * Hyperreal: A theory of Taylor series.
  3220 
  3221 
  3222 *** HOLCF ***
  3223 
  3224 * Discontinued special version of 'constdefs' (which used to support
  3225 continuous functions) in favor of the general Pure one with full
  3226 type-inference.
  3227 
  3228 * New simplification procedure for solving continuity conditions; it
  3229 is much faster on terms with many nested lambda abstractions (cubic
  3230 instead of exponential time).
  3231 
  3232 * New syntax for domain package: selector names are now optional.
  3233 Parentheses should be omitted unless argument is lazy, for example:
  3234 
  3235   domain 'a stream = cons "'a" (lazy "'a stream")
  3236 
  3237 * New command 'fixrec' for defining recursive functions with pattern
  3238 matching; defining multiple functions with mutual recursion is also
  3239 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3240 sinr, or any data constructor defined by the domain package. The given
  3241 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3242 syntax and examples.
  3243 
  3244 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3245 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3246 but the proof obligation additionally includes an admissibility
  3247 requirement. The packages generate instances of class cpo or pcpo,
  3248 with continuity and strictness theorems for Rep and Abs.
  3249 
  3250 * HOLCF: Many theorems have been renamed according to a more standard naming
  3251 scheme (INCOMPATIBILITY):
  3252 
  3253   foo_inject:  "foo$x = foo$y ==> x = y"
  3254   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3255   foo_less:    "(foo$x << foo$y) = (x << y)"
  3256   foo_strict:  "foo$UU = UU"
  3257   foo_defined: "... ==> foo$x ~= UU"
  3258   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3259 
  3260 
  3261 *** ZF ***
  3262 
  3263 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3264 including the First Isomorphism Theorem (on quotienting by the kernel
  3265 of a homomorphism).
  3266 
  3267 * ZF/Simplifier: install second copy of type solver that actually
  3268 makes use of TC rules declared to Isar proof contexts (or locales);
  3269 the old version is still required for ML proof scripts.
  3270 
  3271 
  3272 *** Cube ***
  3273 
  3274 * Converted to Isar theory format; use locales instead of axiomatic
  3275 theories.
  3276 
  3277 
  3278 *** ML ***
  3279 
  3280 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3281 for ||>, ||>>, |>>,
  3282 
  3283 * Pure/library.ML no longer defines its own option datatype, but uses
  3284 that of the SML basis, which has constructors NONE and SOME instead of
  3285 None and Some, as well as exception Option.Option instead of OPTION.
  3286 The functions the, if_none, is_some, is_none have been adapted
  3287 accordingly, while Option.map replaces apsome.
  3288 
  3289 * Pure/library.ML: the exception LIST has been given up in favour of
  3290 the standard exceptions Empty and Subscript, as well as
  3291 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3292 superceded by the standard hd and tl functions etc.
  3293 
  3294 A number of basic list functions are no longer exported to the ML
  3295 toplevel, as they are variants of predefined functions.  The following
  3296 suggests how one can translate existing code:
  3297 
  3298     rev_append xs ys = List.revAppend (xs, ys)
  3299     nth_elem (i, xs) = List.nth (xs, i)
  3300     last_elem xs = List.last xs
  3301     flat xss = List.concat xss
  3302     seq fs = List.app fs
  3303     partition P xs = List.partition P xs
  3304     mapfilter f xs = List.mapPartial f xs
  3305 
  3306 * Pure/library.ML: several combinators for linear functional
  3307 transformations, notably reverse application and composition:
  3308 
  3309   x |> f                f #> g
  3310   (x, y) |-> f          f #-> g
  3311 
  3312 * Pure/library.ML: introduced/changed precedence of infix operators:
  3313 
  3314   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3315   infix 2 ?;
  3316   infix 3 o oo ooo oooo;
  3317   infix 4 ~~ upto downto;
  3318 
  3319 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3320 infix operators.
  3321 
  3322 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3323 fold_map support linear functional transformations and nesting.  For
  3324 example:
  3325 
  3326   fold f [x1, ..., xN] y =
  3327     y |> f x1 |> ... |> f xN
  3328 
  3329   (fold o fold) f [xs1, ..., xsN] y =
  3330     y |> fold f xs1 |> ... |> fold f xsN
  3331 
  3332   fold f [x1, ..., xN] =
  3333     f x1 #> ... #> f xN
  3334 
  3335   (fold o fold) f [xs1, ..., xsN] =
  3336     fold f xs1 #> ... #> fold f xsN
  3337 
  3338 * Pure/library.ML: the following selectors on type 'a option are
  3339 available:
  3340 
  3341   the:               'a option -> 'a  (*partial*)
  3342   these:             'a option -> 'a  where 'a = 'b list
  3343   the_default: 'a -> 'a option -> 'a
  3344   the_list:          'a option -> 'a list
  3345 
  3346 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3347 basic operations for association lists, following natural argument
  3348 order; moreover the explicit equality predicate passed here avoids
  3349 potentially expensive polymorphic runtime equality checks.
  3350 The old functions may be expressed as follows:
  3351 
  3352   assoc = uncurry (AList.lookup (op =))
  3353   assocs = these oo AList.lookup (op =)
  3354   overwrite = uncurry (AList.update (op =)) o swap
  3355 
  3356 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3357 
  3358   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3359   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3360 
  3361 replacing make_keylist and keyfilter (occassionally used)
  3362 Naive rewrites:
  3363 
  3364   make_keylist = AList.make
  3365   keyfilter = AList.find (op =)
  3366 
  3367 * eq_fst and eq_snd now take explicit equality parameter, thus
  3368   avoiding eqtypes. Naive rewrites:
  3369 
  3370     eq_fst = eq_fst (op =)
  3371     eq_snd = eq_snd (op =)
  3372 
  3373 * Removed deprecated apl and apr (rarely used).
  3374   Naive rewrites:
  3375 
  3376     apl (n, op) =>>= curry op n
  3377     apr (op, m) =>>= fn n => op (n, m)
  3378 
  3379 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3380 provides a reasonably efficient light-weight implementation of sets as
  3381 lists.
  3382 
  3383 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3384 few new operations; existing lookup and update are now curried to
  3385 follow natural argument order (for use with fold etc.);
  3386 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3387 
  3388 * Pure/General: output via the Isabelle channels of
  3389 writeln/warning/error etc. is now passed through Output.output, with a
  3390 hook for arbitrary transformations depending on the print_mode
  3391 (cf. Output.add_mode -- the first active mode that provides a output
  3392 function wins).  Already formatted output may be embedded into further
  3393 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3394 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3395 accommodate easy composition of diagnostic messages etc.  Programmers
  3396 rarely need to care about Output.output or Output.raw at all, with
  3397 some notable exceptions: Output.output is required when bypassing the
  3398 standard channels (writeln etc.), or in token translations to produce
  3399 properly formatted results; Output.raw is required when capturing
  3400 already output material that will eventually be presented to the user
  3401 a second time.  For the default print mode, both Output.output and
  3402 Output.raw have no effect.
  3403 
  3404 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3405 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3406 cumulative results are displayed at the end of a batch session.
  3407 
  3408 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3409 replaced by File.platform_path and File.shell_path (with appropriate
  3410 hooks).  This provides a clean interface for unusual systems where the
  3411 internal and external process view of file names are different.
  3412 
  3413 * Pure: more efficient orders for basic syntactic entities: added
  3414 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3415 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3416 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3417 orders now -- potential INCOMPATIBILITY for code that depends on a
  3418 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3419 Library.sort_strings on result).
  3420 
  3421 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3422 fold_types traverse types/terms from left to right, observing natural
  3423 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3424 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3425 
  3426 * Pure: name spaces have been refined, with significant changes of the
  3427 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3428 to extern(_table).  The plain name entry path is superceded by a
  3429 general 'naming' context, which also includes the 'policy' to produce
  3430 a fully qualified name and external accesses of a fully qualified
  3431 name; NameSpace.extend is superceded by context dependent
  3432 Sign.declare_name.  Several theory and proof context operations modify
  3433 the naming context.  Especially note Theory.restore_naming and
  3434 ProofContext.restore_naming to get back to a sane state; note that
  3435 Theory.add_path is no longer sufficient to recover from
  3436 Theory.absolute_path in particular.
  3437 
  3438 * Pure: new flags short_names (default false) and unique_names
  3439 (default true) for controlling output of qualified names.  If
  3440 short_names is set, names are printed unqualified.  If unique_names is
  3441 reset, the name prefix is reduced to the minimum required to achieve
  3442 the original result when interning again, even if there is an overlap
  3443 with earlier declarations.
  3444 
  3445 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3446 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3447 (useful for printing error messages).  INCOMPATIBILITY.
  3448 
  3449 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3450 Theory.theory are now identified, referring to the universal
  3451 Context.theory (see Pure/context.ML).  Actual signature and theory
  3452 content is managed as theory data.  The old code and interfaces were
  3453 spread over many files and structures; the new arrangement introduces
  3454 considerable INCOMPATIBILITY to gain more clarity:
  3455 
  3456   Context -- theory management operations (name, identity, inclusion,
  3457     parents, ancestors, merge, etc.), plus generic theory data;
  3458 
  3459   Sign -- logical signature and syntax operations (declaring consts,
  3460     types, etc.), plus certify/read for common entities;
  3461 
  3462   Theory -- logical theory operations (stating axioms, definitions,
  3463     oracles), plus a copy of logical signature operations (consts,
  3464     types, etc.); also a few basic management operations (Theory.copy,
  3465     Theory.merge, etc.)
  3466 
  3467 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3468 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3469 for convenience -- they merely return the theory.
  3470 
  3471 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3472 
  3473 * Pure: the Isar proof context type is already defined early in Pure
  3474 as Context.proof (note that ProofContext.context and Proof.context are
  3475 aliases, where the latter is the preferred name).  This enables other
  3476 Isabelle components to refer to that type even before Isar is present.
  3477 
  3478 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3479 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3480 any of these kinds.  For example, Sign.intern typeK is now
  3481 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3482 Theory.hide_types.  Also note that former
  3483 Theory.hide_classes/types/consts are now
  3484 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3485 internalize their arguments!  INCOMPATIBILITY.
  3486 
  3487 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3488 datatype thmref (with constructors Name and NameSelection) instead of
  3489 plain string -- INCOMPATIBILITY;
  3490 
  3491 * Pure: cases produced by proof methods specify options, where NONE
  3492 means to remove case bindings -- INCOMPATIBILITY in
  3493 (RAW_)METHOD_CASES.
  3494 
  3495 * Pure: the following operations retrieve axioms or theorems from a
  3496 theory node or theory hierarchy, respectively:
  3497 
  3498   Theory.axioms_of: theory -> (string * term) list
  3499   Theory.all_axioms_of: theory -> (string * term) list
  3500   PureThy.thms_of: theory -> (string * thm) list
  3501   PureThy.all_thms_of: theory -> (string * thm) list
  3502 
  3503 * Pure: print_tac now outputs the goal through the trace channel.
  3504 
  3505 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3506 Reference Toplevel.debug (default false) controls detailed printing
  3507 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3508 controls execution profiling -- set to 1 for time and 2 for space
  3509 (both increase the runtime).
  3510 
  3511 * Isar session: The initial use of ROOT.ML is now always timed,
  3512 i.e. the log will show the actual process times, in contrast to the
  3513 elapsed wall-clock time that the outer shell wrapper produces.
  3514 
  3515 * Simplifier: improved handling of bound variables (nameless
  3516 representation, avoid allocating new strings).  Simprocs that invoke
  3517 the Simplifier recursively should use Simplifier.inherit_bounds to
  3518 avoid local name clashes.  Failure to do so produces warnings
  3519 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3520 for further details.
  3521 
  3522 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3523 bindings for all theorems stored within a given theory; this may help
  3524 in porting non-Isar theories to Isar ones, while keeping ML proof
  3525 scripts for the time being.
  3526 
  3527 * ML operator HTML.with_charset specifies the charset begin used for
  3528 generated HTML files.  For example:
  3529 
  3530   HTML.with_charset "utf-8" use_thy "Hebrew";
  3531   HTML.with_charset "utf-8" use_thy "Chinese";
  3532 
  3533 
  3534 *** System ***
  3535 
  3536 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3537 isabelle, isatool etc.).
  3538 
  3539 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3540 isatool doc, isatool mkdir, display_drafts etc.).
  3541 
  3542 * isatool usedir: option -f allows specification of the ML file to be
  3543 used by Isabelle; default is ROOT.ML.
  3544 
  3545 * New isatool version outputs the version identifier of the Isabelle
  3546 distribution being used.
  3547 
  3548 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3549 (containing Boolean satisfiability problems) into Isabelle/HOL
  3550 theories.
  3551 
  3552 
  3553 
  3554 New in Isabelle2004 (April 2004)
  3555 --------------------------------
  3556 
  3557 *** General ***
  3558 
  3559 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3560   Replaces linorder.ML.
  3561 
  3562 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3563   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3564   (\<a>...\<z>), are now considered normal letters, and can therefore
  3565   be used anywhere where an ASCII letter (a...zA...Z) has until
  3566   now. COMPATIBILITY: This obviously changes the parsing of some
  3567   terms, especially where a symbol has been used as a binder, say
  3568   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3569   as an identifier.  Fix it by inserting a space around former
  3570   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3571   existing theory and ML files.
  3572 
  3573 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3574 
  3575 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3576   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3577   a normal (but invisible) letter. For multiple letter subscripts repeat
  3578   \<^isub> like this: x\<^isub>1\<^isub>2.
  3579 
  3580 * Pure: There are now sub-/superscripts that can span more than one
  3581   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3582   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3583   superscript. The new control characters are not identifier parts.
  3584 
  3585 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3586   content of "..." to the latex file instead of \isacntrl... . The "..."
  3587   may consist of any printable characters excluding the end bracket >.
  3588 
  3589 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3590   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3591   declare constants "final", which prevents their being given a definition
  3592   later.  It is useful for constants whose behaviour is fixed axiomatically
  3593   rather than definitionally, such as the meta-logic connectives.
  3594 
  3595 * Pure: 'instance' now handles general arities with general sorts
  3596   (i.e. intersections of classes),
  3597 
  3598 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3599   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3600   It can be changed to alter the colors/layout of generated pages.
  3601 
  3602 
  3603 *** Isar ***
  3604 
  3605 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3606   cut_tac, subgoal_tac and thin_tac:
  3607   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3608     locales are no longer forced to write Isar proof scripts.
  3609     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3610     emulations.
  3611   - INCOMPATIBILITY: names of variables to be instantiated may no
  3612     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3613     This is consistent with the instantiation attribute "where".
  3614 
  3615 * Attributes "where" and "of":
  3616   - Now take type variables of instantiated theorem into account when reading
  3617     the instantiation string.  This fixes a bug that caused instantiated
  3618     theorems to have too special types in some circumstances.
  3619   - "where" permits explicit instantiations of type variables.
  3620 
  3621 * Calculation commands "moreover" and "also" no longer interfere with
  3622   current facts ("this"), admitting arbitrary combinations with "then"
  3623   and derived forms.
  3624 
  3625 * Locales:
  3626   - Goal statements involving the context element "includes" no longer
  3627     generate theorems with internal delta predicates (those ending on
  3628     "_axioms") in the premise.
  3629     Resolve particular premise with <locale>.intro to obtain old form.
  3630   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3631     specification and "includes" elements in goal statement.
  3632   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3633     [intro?] and [elim?] (respectively) by default.
  3634   - Experimental command for instantiation of locales in proof contexts:
  3635         instantiate <label>[<attrs>]: <loc>
  3636     Instantiates locale <loc> and adds all its theorems to the current context
  3637     taking into account their attributes.  Label and attrs are optional
  3638     modifiers, like in theorem declarations.  If present, names of
  3639     instantiated theorems are qualified with <label>, and the attributes
  3640     <attrs> are applied after any attributes these theorems might have already.
  3641       If the locale has assumptions, a chained fact of the form
  3642     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3643     are derived.  The command does not support old-style locales declared
  3644     with "locale (open)".
  3645       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3646 
  3647 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3648   (Isar) contexts.
  3649 
  3650 
  3651 *** HOL ***
  3652 
  3653 * Proof import: new image HOL4 contains the imported library from
  3654   the HOL4 system with about 2500 theorems. It is imported by
  3655   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3656   can be used like any other Isabelle image.  See
  3657   HOL/Import/HOL/README for more information.
  3658 
  3659 * Simplifier:
  3660   - Much improved handling of linear and partial orders.
  3661     Reasoners for linear and partial orders are set up for type classes
  3662     "linorder" and "order" respectively, and are added to the default simpset
  3663     as solvers.  This means that the simplifier can build transitivity chains
  3664     to solve goals from the assumptions.
  3665   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3666     of blast or auto after simplification become unnecessary because the goal
  3667     is solved by simplification already.
  3668 
  3669 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3670     all proved in axiomatic type classes for semirings, rings and fields.
  3671 
  3672 * Numerics:
  3673   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3674     now formalized using the Ring_and_Field theory mentioned above.
  3675   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3676     than before, because now they are set up once in a generic manner.
  3677   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3678     Look for the general versions in Ring_and_Field (and Power if they concern
  3679     exponentiation).
  3680 
  3681 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3682 
  3683 * Records:
  3684   - Record types are now by default printed with their type abbreviation
  3685     instead of the list of all field types. This can be configured via
  3686     the reference "print_record_type_abbr".
  3687   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3688     (not enabled by default).
  3689   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3690     EX x. x = sel r to True (not enabled by default).
  3691   - Tactic "record_split_simp_tac" to split and simplify records added.
  3692 
  3693 * 'specification' command added, allowing for definition by
  3694   specification.  There is also an 'ax_specification' command that
  3695   introduces the new constants axiomatically.
  3696 
  3697 * arith(_tac) is now able to generate counterexamples for reals as well.
  3698 
  3699 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3700 
  3701 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3702   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3703 
  3704 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3705   matrix theory to linear programming.
  3706 
  3707 * Unions and Intersections:
  3708   The latex output syntax of UN and INT has been changed
  3709   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3710   i.e. the index formulae has become a subscript.
  3711   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3712 
  3713 * Unions and Intersections over Intervals:
  3714   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3715   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3716   like in normal math, and corresponding versions for < and for intersection.
  3717 
  3718 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3719   lexicographic dictonary ordering has been added as "lexord".
  3720 
  3721 * ML: the legacy theory structures Int and List have been removed. They had
  3722   conflicted with ML Basis Library structures having the same names.
  3723 
  3724 * 'refute' command added to search for (finite) countermodels.  Only works
  3725   for a fragment of HOL.  The installation of an external SAT solver is
  3726   highly recommended.  See "HOL/Refute.thy" for details.
  3727 
  3728 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3729   formulae under an assignment of free variables to random values.
  3730   In contrast to 'refute', it can deal with inductive datatypes,
  3731   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3732   for examples.
  3733 
  3734 
  3735 *** HOLCF ***
  3736 
  3737 * Streams now come with concatenation and are part of the HOLCF image
  3738 
  3739 
  3740 
  3741 New in Isabelle2003 (May 2003)
  3742 ------------------------------
  3743 
  3744 *** General ***
  3745 
  3746 * Provers/simplifier:
  3747 
  3748   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3749     Assumptions are now subject to complete mutual simplification,
  3750     not just from left to right. The simplifier now preserves
  3751     the order of assumptions.
  3752 
  3753     Potential INCOMPATIBILITY:
  3754 
  3755     -- simp sometimes diverges where the old version did
  3756        not, e.g. invoking simp on the goal
  3757 
  3758         [| P (f x); y = x; f x = f y |] ==> Q
  3759 
  3760        now gives rise to the infinite reduction sequence
  3761 
  3762         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3763 
  3764        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3765        kind of problem.
  3766 
  3767     -- Tactics combining classical reasoner and simplification (such as auto)
  3768        are also affected by this change, because many of them rely on
  3769        simp. They may sometimes diverge as well or yield a different numbers
  3770        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3771        in case of problems. Sometimes subsequent calls to the classical
  3772        reasoner will fail because a preceeding call to the simplifier too
  3773        eagerly simplified the goal, e.g. deleted redundant premises.
  3774 
  3775   - The simplifier trace now shows the names of the applied rewrite rules
  3776 
  3777   - You can limit the number of recursive invocations of the simplifier
  3778     during conditional rewriting (where the simplifie tries to solve the
  3779     conditions before applying the rewrite rule):
  3780     ML "simp_depth_limit := n"
  3781     where n is an integer. Thus you can force termination where previously
  3782     the simplifier would diverge.
  3783 
  3784   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3785 
  3786   - No longer aborts on failed congruence proof.  Instead, the
  3787     congruence is ignored.
  3788 
  3789 * Pure: New generic framework for extracting programs from constructive
  3790   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3791   as HOL/Extraction for some case studies.
  3792 
  3793 * Pure: The main goal of the proof state is no longer shown by default, only
  3794 the subgoals. This behaviour is controlled by a new flag.
  3795    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3796 (ML: Proof.show_main_goal).
  3797 
  3798 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3799 rules whose conclusion matches subgoal 1:
  3800       PG menu: Isabelle/Isar -> Show me -> matching rules
  3801 The rules are ordered by how closely they match the subgoal.
  3802 In particular, rules that solve a subgoal outright are displayed first
  3803 (or rather last, the way they are printed).
  3804 (ML: ProofGeneral.print_intros())
  3805 
  3806 * Pure: New flag trace_unify_fail causes unification to print
  3807 diagnostic information (PG: in trace buffer) when it fails. This is
  3808 useful for figuring out why single step proofs like rule, erule or
  3809 assumption failed.
  3810 
  3811 * Pure: Locale specifications now produce predicate definitions
  3812 according to the body of text (covering assumptions modulo local
  3813 definitions); predicate "loc_axioms" covers newly introduced text,
  3814 while "loc" is cumulative wrt. all included locale expressions; the
  3815 latter view is presented only on export into the global theory
  3816 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3817 on the old view without predicates;
  3818 
  3819 * Pure: predefined locales "var" and "struct" are useful for sharing
  3820 parameters (as in CASL, for example); just specify something like
  3821 ``var x + var y + struct M'' as import;
  3822 
  3823 * Pure: improved thms_containing: proper indexing of facts instead of
  3824 raw theorems; check validity of results wrt. current name space;
  3825 include local facts of proof configuration (also covers active
  3826 locales), cover fixed variables in index; may use "_" in term
  3827 specification; an optional limit for the number of printed facts may
  3828 be given (the default is 40);
  3829 
  3830 * Pure: disallow duplicate fact bindings within new-style theory files
  3831 (batch-mode only);
  3832 
  3833 * Provers: improved induct method: assumptions introduced by case
  3834 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3835 the goal statement); "foo" still refers to all facts collectively;
  3836 
  3837 * Provers: the function blast.overloaded has been removed: all constants
  3838 are regarded as potentially overloaded, which improves robustness in exchange
  3839 for slight decrease in efficiency;
  3840 
  3841 * Provers/linorder: New generic prover for transitivity reasoning over
  3842 linear orders.  Note: this prover is not efficient!
  3843 
  3844 * Isar: preview of problems to finish 'show' now produce an error
  3845 rather than just a warning (in interactive mode);
  3846 
  3847 
  3848 *** HOL ***
  3849 
  3850 * arith(_tac)
  3851 
  3852  - Produces a counter example if it cannot prove a goal.
  3853    Note that the counter example may be spurious if the goal is not a formula
  3854    of quantifier-free linear arithmetic.
  3855    In ProofGeneral the counter example appears in the trace buffer.
  3856 
  3857  - Knows about div k and mod k where k is a numeral of type nat or int.
  3858 
  3859  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3860    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3861    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3862 
  3863 * simp's arithmetic capabilities have been enhanced a bit: it now
  3864 takes ~= in premises into account (by performing a case split);
  3865 
  3866 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3867 are distributed over a sum of terms;
  3868 
  3869 * New tactic "trans_tac" and method "trans" instantiate
  3870 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3871 "<=", "<" and "=").
  3872 
  3873 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3874 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3875 
  3876 * 'typedef' command has new option "open" to suppress the set
  3877 definition;
  3878 
  3879 * functions Min and Max on finite sets have been introduced (theory
  3880 Finite_Set);
  3881 
  3882 * attribute [symmetric] now works for relations as well; it turns
  3883 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3884 
  3885 * induct over a !!-quantified statement (say !!x1..xn):
  3886   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3887 
  3888 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3889 %x. None. Warning: empty_def now refers to the previously hidden definition
  3890 of the empty set.
  3891 
  3892 * Algebra: formalization of classical algebra.  Intended as base for
  3893 any algebraic development in Isabelle.  Currently covers group theory
  3894 (up to Sylow's theorem) and ring theory (Universal Property of
  3895 Univariate Polynomials).  Contributions welcome;
  3896 
  3897 * GroupTheory: deleted, since its material has been moved to Algebra;
  3898 
  3899 * Complex: new directory of the complex numbers with numeric constants,
  3900 nonstandard complex numbers, and some complex analysis, standard and
  3901 nonstandard (Jacques Fleuriot);
  3902 
  3903 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3904 
  3905 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3906 Fleuriot);
  3907 
  3908 * Real/HahnBanach: updated and adapted to locales;
  3909 
  3910 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3911 Gray and Kramer);
  3912 
  3913 * UNITY: added the Meier-Sanders theory of progress sets;
  3914 
  3915 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3916 as abstract algorithms, instantiated to the JVM;
  3917 
  3918 * Bali: Java source language formalization. Type system, operational
  3919 semantics, axiomatic semantics. Supported language features:
  3920 classes, interfaces, objects,virtual methods, static methods,
  3921 static/instance fields, arrays, access modifiers, definite
  3922 assignment, exceptions.
  3923 
  3924 
  3925 *** ZF ***
  3926 
  3927 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3928 universe, etc.);
  3929 
  3930 * Main ZF: virtually all theories converted to new-style format;
  3931 
  3932 
  3933 *** ML ***
  3934 
  3935 * Pure: Tactic.prove provides sane interface for internal proofs;
  3936 omits the infamous "standard" operation, so this is more appropriate
  3937 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3938 
  3939 * Pure: improved error reporting of simprocs;
  3940 
  3941 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3942 up simprocs;
  3943 
  3944 
  3945 *** Document preparation ***
  3946 
  3947 * uses \par instead of \\ for line breaks in theory text. This may
  3948 shift some page breaks in large documents. To get the old behaviour
  3949 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3950 
  3951 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3952 other packages
  3953 
  3954 * \<euro> now needs package babel/greek instead of marvosym (which
  3955 broke \Rightarrow)
  3956 
  3957 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3958 textcomp package)
  3959 
  3960 
  3961 
  3962 New in Isabelle2002 (March 2002)
  3963 --------------------------------
  3964 
  3965 *** Document preparation ***
  3966 
  3967 * greatly simplified document preparation setup, including more
  3968 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3969 instructive isatool mkdir; users should basically be able to get
  3970 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3971 users may run a separate document processing stage manually like this:
  3972 "isatool usedir -D output HOL Test && isatool document Test/output";
  3973 
  3974 * theory dependency graph may now be incorporated into documents;
  3975 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3976 with \includegraphics of LaTeX;
  3977 
  3978 * proper spacing of consecutive markup elements, especially text
  3979 blocks after section headings;
  3980 
  3981 * support bold style (for single symbols only), input syntax is like
  3982 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3983 
  3984 * \<bullet> is now output as bold \cdot by default, which looks much
  3985 better in printed text;
  3986 
  3987 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3988 note that these symbols are currently unavailable in Proof General /
  3989 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3990 
  3991 * isatool latex no longer depends on changed TEXINPUTS, instead
  3992 isatool document copies the Isabelle style files to the target
  3993 location;
  3994 
  3995 
  3996 *** Isar ***
  3997 
  3998 * Pure/Provers: improved proof by cases and induction;
  3999   - 'case' command admits impromptu naming of parameters (such as
  4000     "case (Suc n)");
  4001   - 'induct' method divinates rule instantiation from the inductive
  4002     claim; no longer requires excessive ?P bindings for proper
  4003     instantiation of cases;
  4004   - 'induct' method properly enumerates all possibilities of set/type
  4005     rules; as a consequence facts may be also passed through *type*
  4006     rules without further ado;
  4007   - 'induct' method now derives symbolic cases from the *rulified*
  4008     rule (before it used to rulify cases stemming from the internal
  4009     atomized version); this means that the context of a non-atomic
  4010     statement becomes is included in the hypothesis, avoiding the
  4011     slightly cumbersome show "PROP ?case" form;
  4012   - 'induct' may now use elim-style induction rules without chaining
  4013     facts, using ``missing'' premises from the goal state; this allows
  4014     rules stemming from inductive sets to be applied in unstructured
  4015     scripts, while still benefitting from proper handling of non-atomic
  4016     statements; NB: major inductive premises need to be put first, all
  4017     the rest of the goal is passed through the induction;
  4018   - 'induct' proper support for mutual induction involving non-atomic
  4019     rule statements (uses the new concept of simultaneous goals, see
  4020     below);
  4021   - append all possible rule selections, but only use the first
  4022     success (no backtracking);
  4023   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4024   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4025   - added 'print_induct_rules' (covered by help item in recent Proof
  4026     General versions);
  4027   - moved induct/cases attributes to Pure, methods to Provers;
  4028   - generic method setup instantiated for FOL and HOL;
  4029 
  4030 * Pure: support multiple simultaneous goal statements, for example
  4031 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4032 meta-level mechanism, this acts as if several individual goals had
  4033 been stated separately; in particular common proof methods need to be
  4034 repeated in order to cover all claims; note that a single elimination
  4035 step is *not* sufficient to establish the two conjunctions, so this
  4036 fails:
  4037 
  4038   assume "A & B" then have A and B ..   (*".." fails*)
  4039 
  4040 better use "obtain" in situations as above; alternative refer to
  4041 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4042 
  4043 * Pure: proper integration with ``locales''; unlike the original
  4044 version by Florian Kammller, Isar locales package high-level proof
  4045 contexts rather than raw logical ones (e.g. we admit to include
  4046 attributes everywhere); operations on locales include merge and
  4047 rename; support for implicit arguments (``structures''); simultaneous
  4048 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4049 some examples;
  4050 
  4051 * Pure: the following commands have been ``localized'', supporting a
  4052 target locale specification "(in name)": 'lemma', 'theorem',
  4053 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4054 stored both within the locale and at the theory level (exported and
  4055 qualified by the locale name);
  4056 
  4057 * Pure: theory goals may now be specified in ``long'' form, with
  4058 ad-hoc contexts consisting of arbitrary locale elements. for example
  4059 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4060 definitions may be given, too); the result is a meta-level rule with
  4061 the context elements being discharged in the obvious way;
  4062 
  4063 * Pure: new proof command 'using' allows to augment currently used
  4064 facts after a goal statement ('using' is syntactically analogous to
  4065 'apply', but acts on the goal's facts only); this allows chained facts
  4066 to be separated into parts given before and after a claim, as in
  4067 ``from a and b have C using d and e <proof>'';
  4068 
  4069 * Pure: renamed "antecedent" case to "rule_context";
  4070 
  4071 * Pure: new 'judgment' command records explicit information about the
  4072 object-logic embedding (used by several tools internally); no longer
  4073 use hard-wired "Trueprop";
  4074 
  4075 * Pure: added 'corollary' command;
  4076 
  4077 * Pure: fixed 'token_translation' command;
  4078 
  4079 * Pure: removed obsolete 'exported' attribute;
  4080 
  4081 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4082 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4083 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4084 
  4085 * Pure: method 'atomize' presents local goal premises as object-level
  4086 statements (atomic meta-level propositions); setup controlled via
  4087 rewrite rules declarations of 'atomize' attribute; example
  4088 application: 'induct' method with proper rule statements in improper
  4089 proof *scripts*;
  4090 
  4091 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4092 now consider the syntactic context of assumptions, giving a better
  4093 chance to get type-inference of the arguments right (this is
  4094 especially important for locales);
  4095 
  4096 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4097 mode;
  4098 
  4099 * Pure/obtain: the formal conclusion "thesis", being marked as
  4100 ``internal'', may no longer be reference directly in the text;
  4101 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4102 situations;
  4103 
  4104 * Pure: generic 'sym' attribute which declares a rule both as pure
  4105 'elim?' and for the 'symmetric' operation;
  4106 
  4107 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4108 text; the fixed correlation with particular command syntax has been
  4109 discontinued;
  4110 
  4111 * Pure: new method 'rules' is particularly well-suited for proof
  4112 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4113 but often produces more compact proof terms with less detours;
  4114 
  4115 * Pure/Provers/classical: simplified integration with pure rule
  4116 attributes and methods; the classical "intro?/elim?/dest?"
  4117 declarations coincide with the pure ones; the "rule" method no longer
  4118 includes classically swapped intros; "intro" and "elim" methods no
  4119 longer pick rules from the context; also got rid of ML declarations
  4120 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4121 INCOMPATIBILITY;
  4122 
  4123 * Provers/classical: attribute 'swapped' produces classical inversions
  4124 of introduction rules;
  4125 
  4126 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4127 rules instead of full simplifier context; 'iff' attribute handles
  4128 conditional rules;
  4129 
  4130 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4131 
  4132 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4133 "(permissive)" option to recover old behavior;
  4134 
  4135 * HOL: 'inductive' no longer features separate (collective) attributes
  4136 for 'intros' (was found too confusing);
  4137 
  4138 * HOL: properly declared induction rules less_induct and
  4139 wf_induct_rule;
  4140 
  4141 
  4142 *** HOL ***
  4143 
  4144 * HOL: moved over to sane numeral syntax; the new policy is as
  4145 follows:
  4146 
  4147   - 0 and 1 are polymorphic constants, which are defined on any
  4148   numeric type (nat, int, real etc.);
  4149 
  4150   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4151   binary representation internally;
  4152 
  4153   - type nat has special constructor Suc, and generally prefers Suc 0
  4154   over 1::nat and Suc (Suc 0) over 2::nat;
  4155 
  4156 This change may cause significant problems of INCOMPATIBILITY; here
  4157 are some hints on converting existing sources:
  4158 
  4159   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4160   entities, so expressions involving "-" (unary or binary minus) need
  4161   to be spaced properly;
  4162 
  4163   - existing occurrences of "1" may need to be constraint "1::nat" or
  4164   even replaced by Suc 0; similar for old "2";
  4165 
  4166   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4167 
  4168   - remove all special provisions on numerals in proofs;
  4169 
  4170 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4171 representation (depends on bin_arith_simps in the default context);
  4172 
  4173 * HOL: symbolic syntax for x^2 (numeral 2);
  4174 
  4175 * HOL: the class of all HOL types is now called "type" rather than
  4176 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4177 in axclass/classes, instance/arities, and (usually rare) occurrences
  4178 in typings (of consts etc.); internally the class is called
  4179 "HOL.type", ML programs should refer to HOLogic.typeS;
  4180 
  4181 * HOL/record package improvements:
  4182   - new derived operations "fields" to build a partial record section,
  4183     "extend" to promote a fixed record to a record scheme, and
  4184     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4185     declared as simp by default;
  4186   - shared operations ("more", "fields", etc.) now need to be always
  4187     qualified) --- potential INCOMPATIBILITY;
  4188   - removed "make_scheme" operations (use "make" with "extend") --
  4189     INCOMPATIBILITY;
  4190   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4191   - provides cases/induct rules for use with corresponding Isar
  4192     methods (for concrete records, record schemes, concrete more
  4193     parts, and schematic more parts -- in that order);
  4194   - internal definitions directly based on a light-weight abstract
  4195     theory of product types over typedef rather than datatype;
  4196 
  4197 * HOL: generic code generator for generating executable ML code from
  4198 specifications; specific support for HOL constructs such as inductive
  4199 datatypes and sets, as well as recursive functions; can be invoked
  4200 via 'generate_code' theory section;
  4201 
  4202 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4203 
  4204 * HOL: consolidated and renamed several theories.  In particular:
  4205         Ord.thy has been absorbed into HOL.thy
  4206         String.thy has been absorbed into List.thy
  4207 
  4208 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4209 (beware of argument permutation!);
  4210 
  4211 * HOL: linorder_less_split superseded by linorder_cases;
  4212 
  4213 * HOL/List: "nodups" renamed to "distinct";
  4214 
  4215 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4216 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4217   - Ex_def has changed, now need to use some_eq_ex
  4218 
  4219 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4220 in this (rare) case use:
  4221 
  4222   delSWrapper "split_all_tac"
  4223   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4224 
  4225 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4226 MAY FAIL;
  4227 
  4228 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4229 Isabelle's type classes, ^ on functions and relations has too general
  4230 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4231 necessary to attach explicit type constraints;
  4232 
  4233 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4234 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4235 renamed accordingly (eg "compI" -> "rel_compI").
  4236 
  4237 * HOL: syntax translations now work properly with numerals and records
  4238 expressions;
  4239 
  4240 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4241 of "lam" -- INCOMPATIBILITY;
  4242 
  4243 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4244 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4245 renamed "Product_Type.unit";
  4246 
  4247 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4248 
  4249 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4250 the "cases" method);
  4251 
  4252 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4253 Florian Kammller);
  4254 
  4255 * HOL/IMP: updated and converted to new-style theory format; several
  4256 parts turned into readable document, with proper Isar proof texts and
  4257 some explanations (by Gerwin Klein);
  4258 
  4259 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4260 
  4261 * HOL-Hyperreal is now a logic image;
  4262 
  4263 
  4264 *** HOLCF ***
  4265 
  4266 * Isar: consts/constdefs supports mixfix syntax for continuous
  4267 operations;
  4268 
  4269 * Isar: domain package adapted to new-style theory format, e.g. see
  4270 HOLCF/ex/Dnat.thy;
  4271 
  4272 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4273 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4274 lift.induct_tac, always use UU instead of Undef;
  4275 
  4276 * HOLCF/IMP: updated and converted to new-style theory;
  4277 
  4278 
  4279 *** ZF ***
  4280 
  4281 * Isar: proper integration of logic-specific tools and packages,
  4282 including theory commands '(co)inductive', '(co)datatype',
  4283 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4284 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4285 
  4286 * theory Main no longer includes AC; for the Axiom of Choice, base
  4287 your theory on Main_ZFC;
  4288 
  4289 * the integer library now covers quotients and remainders, with many
  4290 laws relating division to addition, multiplication, etc.;
  4291 
  4292 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4293 typeless version of the formalism;
  4294 
  4295 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4296 format;
  4297 
  4298 * ZF/Induct: new directory for examples of inductive definitions,
  4299 including theory Multiset for multiset orderings; converted to
  4300 new-style theory format;
  4301 
  4302 * ZF: many new theorems about lists, ordinals, etc.;
  4303 
  4304 
  4305 *** General ***
  4306 
  4307 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4308 variable proof controls level of detail: 0 = no proofs (only oracle
  4309 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4310 also ref manual for further ML interfaces;
  4311 
  4312 * Pure/axclass: removed obsolete ML interface
  4313 goal_subclass/goal_arity;
  4314 
  4315 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4316 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4317 separate tokens, so expressions involving minus need to be spaced
  4318 properly;
  4319 
  4320 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4321 rather than "infixl" or "infixr";
  4322 
  4323 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4324 sort constraint specifications in type inference; e.g. "x::_::foo"
  4325 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4326 type variable);
  4327 
  4328 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4329 control output of nested => (types); the default behavior is
  4330 "type_brackets";
  4331 
  4332 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4333 tokens into AST constants;
  4334 
  4335 * Pure/syntax: prefer later declarations of translations and print
  4336 translation functions; potential INCOMPATIBILITY: need to reverse
  4337 multiple declarations for same syntax element constant;
  4338 
  4339 * Pure/show_hyps reset by default (in accordance to existing Isar
  4340 practice);
  4341 
  4342 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4343 addSafter;
  4344 
  4345 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4346 as well;
  4347 
  4348 * system: tested support for MacOS X; should be able to get Isabelle +
  4349 Proof General to work in a plain Terminal after installing Poly/ML
  4350 (e.g. from the Isabelle distribution area) and GNU bash alone
  4351 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4352 support requires further installations, e.g. from
  4353 http://fink.sourceforge.net/);
  4354 
  4355 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4356 
  4357 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4358 of 40 MB), cf. ML_OPTIONS;
  4359 
  4360 * system: Proof General keywords specification is now part of the
  4361 Isabelle distribution (see etc/isar-keywords.el);
  4362 
  4363 * system: support for persistent Proof General sessions (refrain from
  4364 outdating all loaded theories on startup); user may create writable
  4365 logic images like this: ``isabelle -q HOL Test'';
  4366 
  4367 * system: smart selection of Isabelle process versus Isabelle
  4368 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4369 run both "isabelle" and "Isabelle" even if file names are badly
  4370 damaged (executable inspects the case of the first letter of its own
  4371 name); added separate "isabelle-process" and "isabelle-interface";
  4372 
  4373 * system: refrain from any attempt at filtering input streams; no
  4374 longer support ``8bit'' encoding of old isabelle font, instead proper
  4375 iso-latin characters may now be used; the related isatools
  4376 "symbolinput" and "nonascii" have disappeared as well;
  4377 
  4378 * system: removed old "xterm" interface (the print modes "xterm" and
  4379 "xterm_color" are still available for direct use in a suitable
  4380 terminal);
  4381 
  4382 
  4383 
  4384 New in Isabelle99-2 (February 2001)
  4385 -----------------------------------
  4386 
  4387 *** Overview of INCOMPATIBILITIES ***
  4388 
  4389 * HOL: please note that theories in the Library and elsewhere often use the
  4390 new-style (Isar) format; to refer to their theorems in an ML script you must
  4391 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4392 
  4393 * HOL: inductive package no longer splits induction rule aggressively,
  4394 but only as far as specified by the introductions given; the old
  4395 format may be recovered via ML function complete_split_rule or attribute
  4396 'split_rule (complete)';
  4397 
  4398 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4399 gfp_Tarski to gfp_unfold;
  4400 
  4401 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4402 
  4403 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4404 relation); infix "^^" has been renamed "``"; infix "``" has been
  4405 renamed "`"; "univalent" has been renamed "single_valued";
  4406 
  4407 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4408 operation;
  4409 
  4410 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4411 
  4412 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4413 
  4414 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4415 consequence, it is no longer monotonic wrt. the local goal context
  4416 (which is now passed through the inductive cases);
  4417 
  4418 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4419 \<gg> to \<ggreater>;
  4420 
  4421 
  4422 *** Document preparation ***
  4423 
  4424 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4425 available: are "it" for near math-mode best-style output, "sl" for
  4426 slanted text style, and "tt" for plain type-writer; if no
  4427 \isabellestyle command is given, output is according to slanted
  4428 type-writer);
  4429 
  4430 * support sub/super scripts (for single symbols only), input syntax is
  4431 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4432 
  4433 * some more standard symbols; see Appendix A of the system manual for
  4434 the complete list of symbols defined in isabellesym.sty;
  4435 
  4436 * improved isabelle style files; more abstract symbol implementation
  4437 (should now use \isamath{...} and \isatext{...} in custom symbol
  4438 definitions);
  4439 
  4440 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4441 state; Note that presentation of goal states does not conform to
  4442 actual human-readable proof documents.  Please do not include goal
  4443 states into document output unless you really know what you are doing!
  4444 
  4445 * proper indentation of antiquoted output with proportional LaTeX
  4446 fonts;
  4447 
  4448 * no_document ML operator temporarily disables LaTeX document
  4449 generation;
  4450 
  4451 * isatool unsymbolize tunes sources for plain ASCII communication;
  4452 
  4453 
  4454 *** Isar ***
  4455 
  4456 * Pure: Isar now suffers initial goal statements to contain unbound
  4457 schematic variables (this does not conform to actual readable proof
  4458 documents, due to unpredictable outcome and non-compositional proof
  4459 checking); users who know what they are doing may use schematic goals
  4460 for Prolog-style synthesis of proven results;
  4461 
  4462 * Pure: assumption method (an implicit finishing) now handles actual
  4463 rules as well;
  4464 
  4465 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4466 initial goal, declare "that" only as Pure intro (only for single
  4467 steps); the "that" rule assumption may now be involved in implicit
  4468 finishing, thus ".." becomes a feasible for trivial obtains;
  4469 
  4470 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4471 instance proofs may be performed by "..";
  4472 
  4473 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4474 statements as well;
  4475 
  4476 * Pure: more robust selection of calculational rules;
  4477 
  4478 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4479 rule (as well as the assumption rule);
  4480 
  4481 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4482 lemmas, using the graph browser tool;
  4483 
  4484 * Pure: predict failure of "show" in interactive mode;
  4485 
  4486 * Pure: 'thms_containing' now takes actual terms as arguments;
  4487 
  4488 * HOL: improved method 'induct' --- now handles non-atomic goals
  4489 (potential INCOMPATIBILITY); tuned error handling;
  4490 
  4491 * HOL: cases and induct rules now provide explicit hints about the
  4492 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4493 any remaining facts are inserted into the goal verbatim;
  4494 
  4495 * HOL: local contexts (aka cases) may now contain term bindings as
  4496 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4497 the result to be shown in each case;
  4498 
  4499 * HOL: added 'recdef_tc' command;
  4500 
  4501 * isatool convert assists in eliminating legacy ML scripts;
  4502 
  4503 
  4504 *** HOL ***
  4505 
  4506 * HOL/Library: a collection of generic theories to be used together
  4507 with main HOL; the theory loader path already includes this directory
  4508 by default; the following existing theories have been moved here:
  4509 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4510 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4511 
  4512 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4513 modelling and verification task performed in Isabelle/HOL +
  4514 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4515 
  4516 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4517 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4518 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4519 'domain', this makes the theory consistent with mathematical
  4520 literature;
  4521 
  4522 * HOL basics: added overloaded operations "inverse" and "divide"
  4523 (infix "/"), syntax for generic "abs" operation, generic summation
  4524 operator \<Sum>;
  4525 
  4526 * HOL/typedef: simplified package, provide more useful rules (see also
  4527 HOL/subset.thy);
  4528 
  4529 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4530 now expressed as a proper nested rule (old-style tactic scripts may
  4531 require atomize_strip_tac to cope with non-atomic premises);
  4532 
  4533 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4534 to "split_conv" (old name still available for compatibility);
  4535 
  4536 * HOL: improved concrete syntax for strings (e.g. allows translation
  4537 rules with string literals);
  4538 
  4539 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4540  and Fleuriot's mechanization of analysis, including the transcendental
  4541  functions for the reals;
  4542 
  4543 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4544 
  4545 
  4546 *** CTT ***
  4547 
  4548 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4549 "lam" is displayed as TWO lambda-symbols
  4550 
  4551 * CTT: theory Main now available, containing everything (that is, Bool
  4552 and Arith);
  4553 
  4554 
  4555 *** General ***
  4556 
  4557 * Pure: the Simplifier has been implemented properly as a derived rule
  4558 outside of the actual kernel (at last!); the overall performance
  4559 penalty in practical applications is about 50%, while reliability of
  4560 the Isabelle inference kernel has been greatly improved;
  4561 
  4562 * print modes "brackets" and "no_brackets" control output of nested =>
  4563 (types) and ==> (props); the default behaviour is "brackets";
  4564 
  4565 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4566 as assumptions as well;
  4567 
  4568 * system: support Poly/ML 4.0;
  4569 
  4570 * system: isatool install handles KDE version 1 or 2;
  4571 
  4572 
  4573 
  4574 New in Isabelle99-1 (October 2000)
  4575 ----------------------------------
  4576 
  4577 *** Overview of INCOMPATIBILITIES ***
  4578 
  4579 * HOL: simplification of natural numbers is much changed; to partly
  4580 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4581 issue the following ML commands:
  4582 
  4583   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4584   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4585 
  4586 * HOL: simplification no longer dives into case-expressions; this is
  4587 controlled by "t.weak_case_cong" for each datatype t;
  4588 
  4589 * HOL: nat_less_induct renamed to less_induct;
  4590 
  4591 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4592 fixsome to patch .thy and .ML sources automatically;
  4593 
  4594   select_equality  -> some_equality
  4595   select_eq_Ex     -> some_eq_ex
  4596   selectI2EX       -> someI2_ex
  4597   selectI2         -> someI2
  4598   selectI          -> someI
  4599   select1_equality -> some1_equality
  4600   Eps_sym_eq       -> some_sym_eq_trivial
  4601   Eps_eq           -> some_eq_trivial
  4602 
  4603 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4604 
  4605 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4606 instead);
  4607 
  4608 * HOL: the recursion equations generated by 'recdef' are now called
  4609 f.simps instead of f.rules;
  4610 
  4611 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4612 
  4613 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4614 sometimes be needed;
  4615 
  4616 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4617 
  4618 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4619 
  4620 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4621 product is now "<*>" instead of "Times"; the lexicographic product is
  4622 now "<*lex*>" instead of "**";
  4623 
  4624 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4625 of main HOL, but was unused); better use HOL's datatype package;
  4626 
  4627 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4628 the old syntax may be recovered as follows:
  4629 
  4630   syntax (symbols)
  4631     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4632       (infixl "\\<oplus>" 100)
  4633 
  4634 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4635 
  4636 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4637 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4638 internally;
  4639 
  4640 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4641 changed from A/r to A//r;
  4642 
  4643 * ZF: new treatment of arithmetic (nat & int) may break some old
  4644 proofs;
  4645 
  4646 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4647 rulify -> rule_format, elimify -> elim_format, ...);
  4648 
  4649 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4650 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4651 should have to change intro!! to intro? only); replaced "delrule" by
  4652 "rule del";
  4653 
  4654 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4655 
  4656 * Provers: strengthened force_tac by using new first_best_tac;
  4657 
  4658 * LaTeX document preparation: several changes of isabelle.sty (see
  4659 lib/texinputs);
  4660 
  4661 
  4662 *** Document preparation ***
  4663 
  4664 * formal comments (text blocks etc.) in new-style theories may now
  4665 contain antiquotations of thm/prop/term/typ/text to be presented
  4666 according to latex print mode; concrete syntax is like this:
  4667 @{term[show_types] "f(x) = a + x"};
  4668 
  4669 * isatool mkdir provides easy setup of Isabelle session directories,
  4670 including proper document sources;
  4671 
  4672 * generated LaTeX sources are now deleted after successful run
  4673 (isatool document -c); may retain a copy somewhere else via -D option
  4674 of isatool usedir;
  4675 
  4676 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4677 style files, achieving self-contained LaTeX sources and simplifying
  4678 LaTeX debugging;
  4679 
  4680 * old-style theories now produce (crude) LaTeX output as well;
  4681 
  4682 * browser info session directories are now self-contained (may be put
  4683 on WWW server seperately); improved graphs of nested sessions; removed
  4684 graph for 'all sessions';
  4685 
  4686 * several improvements in isabelle style files; \isabellestyle{it}
  4687 produces fake math mode output; \isamarkupheader is now \section by
  4688 default; see lib/texinputs/isabelle.sty etc.;
  4689 
  4690 
  4691 *** Isar ***
  4692 
  4693 * Isar/Pure: local results and corresponding term bindings are now
  4694 subject to Hindley-Milner polymorphism (similar to ML); this
  4695 accommodates incremental type-inference very nicely;
  4696 
  4697 * Isar/Pure: new derived language element 'obtain' supports
  4698 generalized existence reasoning;
  4699 
  4700 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4701 support accumulation of results, without applying any rules yet;
  4702 useful to collect intermediate results without explicit name
  4703 references, and for use with transitivity rules with more than 2
  4704 premises;
  4705 
  4706 * Isar/Pure: scalable support for case-analysis type proofs: new
  4707 'case' language element refers to local contexts symbolically, as
  4708 produced by certain proof methods; internally, case names are attached
  4709 to theorems as "tags";
  4710 
  4711 * Isar/Pure: theory command 'hide' removes declarations from
  4712 class/type/const name spaces;
  4713 
  4714 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4715 indicate potential overloading;
  4716 
  4717 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4718 
  4719 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4720 "{a,b,c}" instead of {a,b,c};
  4721 
  4722 * Isar/Pure now provides its own version of intro/elim/dest
  4723 attributes; useful for building new logics, but beware of confusion
  4724 with the version in Provers/classical;
  4725 
  4726 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4727 case name 'antecedent';
  4728 
  4729 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4730 to the current context is now done automatically);
  4731 
  4732 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4733 for definining proof methods in ML;
  4734 
  4735 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4736 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4737 most cases, one should have to change intro!! to intro? only);
  4738 replaced "delrule" by "rule del";
  4739 
  4740 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4741 'symmetric' attribute (the latter supercedes [RS sym]);
  4742 
  4743 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4744 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4745 well (including splits);
  4746 
  4747 * Isar/Provers: Simplifier and Classical methods now support all kind
  4748 of modifiers used in the past, including 'cong', 'iff', etc.
  4749 
  4750 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4751 of Simplifier and Classical reasoner);
  4752 
  4753 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4754 now support named cases; major packages (inductive, datatype, primrec,
  4755 recdef) support case names and properly name parameters;
  4756 
  4757 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4758 monotonicity conditions are extracted to be proven at end of
  4759 calculations;
  4760 
  4761 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4762 method anyway;
  4763 
  4764 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4765 split_if split_if_asm; datatype package provides theorems foo.splits =
  4766 foo.split foo.split_asm for each datatype;
  4767 
  4768 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4769 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4770 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4771 use "(cases (simplified))" method in proper proof texts);
  4772 
  4773 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4774 
  4775 * Isar: names of theorems etc. may be natural numbers as well;
  4776 
  4777 * Isar: 'pr' command: optional arguments for goals_limit and
  4778 ProofContext.prems_limit; no longer prints theory contexts, but only
  4779 proof states;
  4780 
  4781 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4782 additional print modes to be specified; e.g. "pr(latex)" will print
  4783 proof state according to the Isabelle LaTeX style;
  4784 
  4785 * Isar: improved support for emulating tactic scripts, including proof
  4786 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4787 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4788 (for HOL datatypes);
  4789 
  4790 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4791 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4792 'proof method scripts' have to be in depth-first order;
  4793 
  4794 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4795 
  4796 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4797 should instead use individual commands for printing items
  4798 (print_commands, print_methods etc.);
  4799 
  4800 * Isar: added 'nothing' --- the empty list of theorems;
  4801 
  4802 
  4803 *** HOL ***
  4804 
  4805 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4806 corresponding virtual machine and a specification of its bytecode
  4807 verifier and a lightweight bytecode verifier, including proofs of
  4808 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4809 Cornelia Pusch (see also the homepage of project Bali at
  4810 http://isabelle.in.tum.de/Bali/);
  4811 
  4812 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4813 Clemens Ballarin;
  4814 
  4815 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4816 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4817 Rasmussen;
  4818 
  4819 * HOL/Lattice: fundamental concepts of lattice theory and order
  4820 structures, including duals, properties of bounds versus algebraic
  4821 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4822 Theorem for complete lattices etc.; may also serve as a demonstration
  4823 for abstract algebraic reasoning using axiomatic type classes, and
  4824 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4825 
  4826 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4827 von Oheimb;
  4828 
  4829 * HOL/IMPP: extension of IMP with local variables and mutually
  4830 recursive procedures, by David von Oheimb;
  4831 
  4832 * HOL/Lambda: converted into new-style theory and document;
  4833 
  4834 * HOL/ex/Multiquote: example of multiple nested quotations and
  4835 anti-quotations -- basically a generalized version of de-Bruijn
  4836 representation; very useful in avoiding lifting of operations;
  4837 
  4838 * HOL/record: added general record equality rule to simpset; fixed
  4839 select-update simplification procedure to handle extended records as
  4840 well; admit "r" as field name;
  4841 
  4842 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4843 other numeric types and also as the identity of groups, rings, etc.;
  4844 
  4845 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4846 Types nat and int belong to this axclass;
  4847 
  4848 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4849    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4850    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4851   two terms #m*u and #n*u are replaced by #(m+n)*u
  4852     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4853   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4854     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4855 
  4856 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4857 powerful prover for predicate logic but knows nothing of clasets; see
  4858 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4859 
  4860 * HOL: new version of "case_tac" subsumes both boolean case split and
  4861 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4862 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4863 
  4864 * HOL: simplification no longer dives into case-expressions: only the
  4865 selector expression is simplified, but not the remaining arms; to
  4866 enable full simplification of case-expressions for datatype t, you may
  4867 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4868 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4869 
  4870 * HOL/recdef: the recursion equations generated by 'recdef' for
  4871 function 'f' are now called f.simps instead of f.rules; if all
  4872 termination conditions are proved automatically, these simplification
  4873 rules are added to the simpset, as in primrec; rules may be named
  4874 individually as well, resulting in a separate list of theorems for
  4875 each equation;
  4876 
  4877 * HOL/While is a new theory that provides a while-combinator. It
  4878 permits the definition of tail-recursive functions without the
  4879 provision of a termination measure. The latter is necessary once the
  4880 invariant proof rule for while is applied.
  4881 
  4882 * HOL: new (overloaded) notation for the set of elements below/above
  4883 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4884 
  4885 * HOL: theorems impI, allI, ballI bound as "strip";
  4886 
  4887 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4888 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4889 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4890 
  4891 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4892 
  4893 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4894 main HOL, but was unused);
  4895 
  4896 * HOL: fewer consts declared as global (e.g. have to refer to
  4897 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4898 
  4899 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4900 in case of overlap with user translations (e.g. judgements over
  4901 tuples); (note that the underlying logical represenation is still
  4902 bogus);
  4903 
  4904 
  4905 *** ZF ***
  4906 
  4907 * ZF: simplification automatically cancels common terms in arithmetic
  4908 expressions over nat and int;
  4909 
  4910 * ZF: new treatment of nat to minimize type-checking: all operators
  4911 coerce their operands to a natural number using the function natify,
  4912 making the algebraic laws unconditional;
  4913 
  4914 * ZF: as above, for int: operators coerce their operands to an integer
  4915 using the function intify;
  4916 
  4917 * ZF: the integer library now contains many of the usual laws for the
  4918 orderings, including $<=, and monotonicity laws for $+ and $*;
  4919 
  4920 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4921 simplification;
  4922 
  4923 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4924 to the simplifier and classical reasoner simultaneously;
  4925 
  4926 
  4927 *** General ***
  4928 
  4929 * Provers: blast_tac now handles actual object-logic rules as
  4930 assumptions; note that auto_tac uses blast_tac internally as well;
  4931 
  4932 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4933 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4934 
  4935 * Provers: delrules now handles destruct rules as well (no longer need
  4936 explicit make_elim);
  4937 
  4938 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4939   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4940 use instead the strong form,
  4941   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4942 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4943 from destruct-rules;
  4944 
  4945 * Provers: Simplifier.easy_setup provides a fast path to basic
  4946 Simplifier setup for new object-logics;
  4947 
  4948 * Pure: AST translation rules no longer require constant head on LHS;
  4949 
  4950 * Pure: improved name spaces: ambiguous output is qualified; support
  4951 for hiding of names;
  4952 
  4953 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4954 XSYMBOL_HOME; no longer need to do manual configuration in most
  4955 situations;
  4956 
  4957 * system: compression of ML heaps images may now be controlled via -c
  4958 option of isabelle and isatool usedir (currently only observed by
  4959 Poly/ML);
  4960 
  4961 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4962 useful for remote X11);
  4963 
  4964 * system: provide TAGS file for Isabelle sources;
  4965 
  4966 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4967 order;
  4968 
  4969 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4970 timing flag supersedes proof_timing and Toplevel.trace;
  4971 
  4972 * ML: new combinators |>> and |>>> for incremental transformations
  4973 with secondary results (e.g. certain theory extensions):
  4974 
  4975 * ML: PureThy.add_defs gets additional argument to indicate potential
  4976 overloading (usually false);
  4977 
  4978 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4979 results;
  4980 
  4981 
  4982 
  4983 New in Isabelle99 (October 1999)
  4984 --------------------------------
  4985 
  4986 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4987 
  4988 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4989 are no longer simplified.  (This allows the simplifier to unfold recursive
  4990 functional programs.)  To restore the old behaviour, declare
  4991 
  4992     Delcongs [if_weak_cong];
  4993 
  4994 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4995 complement;
  4996 
  4997 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4998 
  4999 * HOL/datatype: mutual_induct_tac no longer exists --
  5000   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5001 
  5002 * HOL/typedef: fixed type inference for representing set; type
  5003 arguments now have to occur explicitly on the rhs as type constraints;
  5004 
  5005 * ZF: The con_defs part of an inductive definition may no longer refer
  5006 to constants declared in the same theory;
  5007 
  5008 * HOL, ZF: the function mk_cases, generated by the inductive
  5009 definition package, has lost an argument.  To simplify its result, it
  5010 uses the default simpset instead of a supplied list of theorems.
  5011 
  5012 * HOL/List: the constructors of type list are now Nil and Cons;
  5013 
  5014 * Simplifier: the type of the infix ML functions
  5015         setSSolver addSSolver setSolver addSolver
  5016 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5017 for packaging solvers. A solver is created via
  5018         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5019 where the string argument is only a comment.
  5020 
  5021 
  5022 *** Proof tools ***
  5023 
  5024 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5025 decision procedure for linear arithmetic. Currently it is used for
  5026 types `nat', `int', and `real' in HOL (see below); it can, should and
  5027 will be instantiated for other types and logics as well.
  5028 
  5029 * The simplifier now accepts rewrite rules with flexible heads, eg
  5030      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5031   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5032   matching.
  5033 
  5034 
  5035 *** General ***
  5036 
  5037 * New Isabelle/Isar subsystem provides an alternative to traditional
  5038 tactical theorem proving; together with the ProofGeneral/isar user
  5039 interface it offers an interactive environment for developing human
  5040 readable proof documents (Isar == Intelligible semi-automated
  5041 reasoning); for further information see isatool doc isar-ref,
  5042 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5043 
  5044 * improved and simplified presentation of theories: better HTML markup
  5045 (including colors), graph views in several sizes; isatool usedir now
  5046 provides a proper interface for user theories (via -P option); actual
  5047 document preparation based on (PDF)LaTeX is available as well (for
  5048 new-style theories only); see isatool doc system for more information;
  5049 
  5050 * native support for Proof General, both for classic Isabelle and
  5051 Isabelle/Isar;
  5052 
  5053 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5054 using the graph browser tool;
  5055 
  5056 * Isabelle manuals now also available as PDF;
  5057 
  5058 * theory loader rewritten from scratch (may not be fully
  5059 bug-compatible); old loadpath variable has been replaced by show_path,
  5060 add_path, del_path, reset_path functions; new operations such as
  5061 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5062 isatool doc ref);
  5063 
  5064 * improved isatool install: option -k creates KDE application icon,
  5065 option -p DIR installs standalone binaries;
  5066 
  5067 * added ML_PLATFORM setting (useful for cross-platform installations);
  5068 more robust handling of platform specific ML images for SML/NJ;
  5069 
  5070 * the settings environment is now statically scoped, i.e. it is never
  5071 created again in sub-processes invoked from isabelle, isatool, or
  5072 Isabelle;
  5073 
  5074 * path element specification '~~' refers to '$ISABELLE_HOME';
  5075 
  5076 * in locales, the "assumes" and "defines" parts may be omitted if
  5077 empty;
  5078 
  5079 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5080 long arrows);
  5081 
  5082 * new print_mode "HTML";
  5083 
  5084 * new flag show_tags controls display of tags of theorems (which are
  5085 basically just comments that may be attached by some tools);
  5086 
  5087 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5088 mode and goal output format:
  5089 
  5090 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5091 244c244
  5092 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5093 ---
  5094 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5095 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5096 181c181
  5097 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5098 ---
  5099 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5100 
  5101 * function bind_thms stores lists of theorems (cf. bind_thm);
  5102 
  5103 * new shorthand tactics ftac, eatac, datac, fatac;
  5104 
  5105 * qed (and friends) now accept "" as result name; in that case the
  5106 theorem is not stored, but proper checks and presentation of the
  5107 result still apply;
  5108 
  5109 * theorem database now also indexes constants "Trueprop", "all",
  5110 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5111 
  5112 
  5113 *** HOL ***
  5114 
  5115 ** HOL arithmetic **
  5116 
  5117 * There are now decision procedures for linear arithmetic over nat and
  5118 int:
  5119 
  5120 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5121 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5122 are treated as atomic; subformulae not involving type `nat' or `int'
  5123 are ignored; quantified subformulae are ignored unless they are
  5124 positive universal or negative existential. The tactic has to be
  5125 invoked by hand and can be a little bit slow. In particular, the
  5126 running time is exponential in the number of occurrences of `min' and
  5127 `max', and `-' on `nat'.
  5128 
  5129 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5130 (negated) (in)equalities among the premises and the conclusion into
  5131 account (i.e. no compound formulae) and does not know about `min' and
  5132 `max', and `-' on `nat'. It is fast and is used automatically by the
  5133 simplifier.
  5134 
  5135 NB: At the moment, these decision procedures do not cope with mixed
  5136 nat/int formulae where the two parts interact, such as `m < n ==>
  5137 int(m) < int(n)'.
  5138 
  5139 * HOL/Numeral provides a generic theory of numerals (encoded
  5140 efficiently as bit strings); setup for types nat/int/real is in place;
  5141 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5142 int, existing theories and proof scripts may require a few additional
  5143 type constraints;
  5144 
  5145 * integer division and remainder can now be performed on constant
  5146 arguments;
  5147 
  5148 * many properties of integer multiplication, division and remainder
  5149 are now available;
  5150 
  5151 * An interface to the Stanford Validity Checker (SVC) is available through the
  5152 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5153 are proved automatically.  SVC must be installed separately, and its results
  5154 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5155 invocation of the underlying oracle).  For SVC see
  5156   http://verify.stanford.edu/SVC
  5157 
  5158 * IsaMakefile: the HOL-Real target now builds an actual image;
  5159 
  5160 
  5161 ** HOL misc **
  5162 
  5163 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5164 (in Isabelle/Isar) -- by Gertrud Bauer;
  5165 
  5166 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5167 analysis for assembly languages with subtypes;
  5168 
  5169 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5170 -- avoids syntactic ambiguities and treats state, transition, and
  5171 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5172 changed syntax and (many) tactics;
  5173 
  5174 * HOL/inductive: Now also handles more general introduction rules such
  5175   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5176   theorems are now maintained within the theory (maintained via the
  5177   "mono" attribute);
  5178 
  5179 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5180   (using function types) such as
  5181 
  5182   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5183 
  5184 * HOL/record: record_simproc (part of the default simpset) takes care
  5185 of selectors applied to updated records; record_split_tac is no longer
  5186 part of the default claset; update_defs may now be removed from the
  5187 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5188 
  5189   claset_ref () := claset() addSWrapper record_split_wrapper;
  5190   Delsimprocs [record_simproc]
  5191 
  5192 * HOL/typedef: fixed type inference for representing set; type
  5193 arguments now have to occur explicitly on the rhs as type constraints;
  5194 
  5195 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5196 names rather than an ML expression;
  5197 
  5198 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5199 supplied later.  Program schemes can be defined, such as
  5200     "While B C s = (if B s then While B C (C s) else s)"
  5201 where the well-founded relation can be chosen after B and C have been given.
  5202 
  5203 * HOL/List: the constructors of type list are now Nil and Cons;
  5204 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5205 course, ML tools referring to List.list.op # etc. have to be adapted;
  5206 
  5207 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5208 disabled by default; run isabelle with option -m HOL to get back to
  5209 the original Gordon/HOL-style output;
  5210 
  5211 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5212 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5213 
  5214 * HOL basic syntax simplified (more orthogonal): all variants of
  5215 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5216 Eps operator is provided as well: "SOME x. P[x]";
  5217 
  5218 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5219 
  5220 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5221 thus available for user theories;
  5222 
  5223 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5224 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5225 time;
  5226 
  5227 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5228 several times and then mp;
  5229 
  5230 
  5231 *** LK ***
  5232 
  5233 * the notation <<...>> is now available as a notation for sequences of
  5234 formulas;
  5235 
  5236 * the simplifier is now installed
  5237 
  5238 * the axiom system has been generalized (thanks to Soren Heilmann)
  5239 
  5240 * the classical reasoner now has a default rule database
  5241 
  5242 
  5243 *** ZF ***
  5244 
  5245 * new primrec section allows primitive recursive functions to be given
  5246 directly (as in HOL) over datatypes and the natural numbers;
  5247 
  5248 * new tactics induct_tac and exhaust_tac for induction (or case
  5249 analysis) over datatypes and the natural numbers;
  5250 
  5251 * the datatype declaration of type T now defines the recursor T_rec;
  5252 
  5253 * simplification automatically does freeness reasoning for datatype
  5254 constructors;
  5255 
  5256 * automatic type-inference, with AddTCs command to insert new
  5257 type-checking rules;
  5258 
  5259 * datatype introduction rules are now added as Safe Introduction rules
  5260 to the claset;
  5261 
  5262 * the syntax "if P then x else y" is now available in addition to
  5263 if(P,x,y);
  5264 
  5265 
  5266 *** Internal programming interfaces ***
  5267 
  5268 * tuned simplifier trace output; new flag debug_simp;
  5269 
  5270 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5271 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5272 
  5273 * AxClass.axclass_tac lost the theory argument;
  5274 
  5275 * tuned current_goals_markers semantics: begin / end goal avoids
  5276 printing empty lines;
  5277 
  5278 * removed prs and prs_fn hook, which was broken because it did not
  5279 include \n in its semantics, forcing writeln to add one
  5280 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5281 string -> unit if you really want to output text without newline;
  5282 
  5283 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5284 plain output, interface builders may have to enable 'isabelle_font'
  5285 mode to get Isabelle font glyphs as before;
  5286 
  5287 * refined token_translation interface; INCOMPATIBILITY: output length
  5288 now of type real instead of int;
  5289 
  5290 * theory loader actions may be traced via new ThyInfo.add_hook
  5291 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5292 your own database of information attached to *whole* theories -- as
  5293 opposed to intra-theory data slots offered via TheoryDataFun;
  5294 
  5295 * proper handling of dangling sort hypotheses (at last!);
  5296 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5297 extra sort hypotheses that can be witnessed from the type signature;
  5298 the force_strip_shyps flag is gone, any remaining shyps are simply
  5299 left in the theorem (with a warning issued by strip_shyps_warning);
  5300 
  5301 
  5302 
  5303 New in Isabelle98-1 (October 1998)
  5304 ----------------------------------
  5305 
  5306 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5307 
  5308 * several changes of automated proof tools;
  5309 
  5310 * HOL: major changes to the inductive and datatype packages, including
  5311 some minor incompatibilities of theory syntax;
  5312 
  5313 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5314 called `inj_on';
  5315 
  5316 * HOL: removed duplicate thms in Arith:
  5317   less_imp_add_less  should be replaced by  trans_less_add1
  5318   le_imp_add_le      should be replaced by  trans_le_add1
  5319 
  5320 * HOL: unary minus is now overloaded (new type constraints may be
  5321 required);
  5322 
  5323 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5324 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5325 now taken as an integer constant.
  5326 
  5327 * Pure: ML function 'theory_of' renamed to 'theory';
  5328 
  5329 
  5330 *** Proof tools ***
  5331 
  5332 * Simplifier:
  5333   1. Asm_full_simp_tac is now more aggressive.
  5334      1. It will sometimes reorient premises if that increases their power to
  5335         simplify.
  5336      2. It does no longer proceed strictly from left to right but may also
  5337         rotate premises to achieve further simplification.
  5338      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5339      old Asm_full_simp_tac in that it does not rotate premises.
  5340   2. The simplifier now knows a little bit about nat-arithmetic.
  5341 
  5342 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5343 allows for selected deletion of wrappers, by introduction of names for
  5344 wrapper functionals.  This implies that addbefore, addSbefore,
  5345 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5346 and that adding two tactics with the same name overwrites the first
  5347 one (emitting a warning).
  5348   type wrapper = (int -> tactic) -> (int -> tactic)
  5349   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5350   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5351   delWrapper, delSWrapper: claset *  string            -> claset
  5352   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5353 
  5354 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5355 semantics; addbefore now affects only the unsafe part of step_tac
  5356 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5357 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5358 by Force_tac;
  5359 
  5360 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5361 compWrapper; added safe wrapper (and access functions for it);
  5362 
  5363 * HOL/split_all_tac is now much faster and fails if there is nothing
  5364 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5365 and the names of the automatically generated variables have changed.
  5366 split_all_tac has moved within claset() from unsafe wrappers to safe
  5367 wrappers, which means that !!-bound variables are split much more
  5368 aggressively, and safe_tac and clarify_tac now split such variables.
  5369 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5370 Note: the same holds for record_split_tac, which does the job of
  5371 split_all_tac for record fields.
  5372 
  5373 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5374 permanently to the default simpset using Addsplits just like
  5375 Addsimps. They can be removed via Delsplits just like
  5376 Delsimps. Lower-case versions are also available.
  5377 
  5378 * HOL/Simplifier: The rule split_if is now part of the default
  5379 simpset. This means that the simplifier will eliminate all occurrences
  5380 of if-then-else in the conclusion of a goal. To prevent this, you can
  5381 either remove split_if completely from the default simpset by
  5382 `Delsplits [split_if]' or remove it in a specific call of the
  5383 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5384 other case splitting rules to/from the default simpset: every datatype
  5385 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5386 t is the name of the datatype).
  5387 
  5388 * Classical reasoner / Simplifier combination: new force_tac (and
  5389 derivatives Force_tac, force) combines rewriting and classical
  5390 reasoning (and whatever other tools) similarly to auto_tac, but is
  5391 aimed to solve the given subgoal completely.
  5392 
  5393 
  5394 *** General ***
  5395 
  5396 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5397 and `goalw': the theory is no longer needed as an explicit argument -
  5398 the current theory context is used; assumptions are no longer returned
  5399 at the ML-level unless one of them starts with ==> or !!; it is
  5400 recommended to convert to these new commands using isatool fixgoal
  5401 (backup your sources first!);
  5402 
  5403 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5404 the current theory context, and 'theory' to lookup stored theories;
  5405 
  5406 * new theory section 'locale' for declaring constants, assumptions and
  5407 definitions that have local scope;
  5408 
  5409 * new theory section 'nonterminals' for purely syntactic types;
  5410 
  5411 * new theory section 'setup' for generic ML setup functions
  5412 (e.g. package initialization);
  5413 
  5414 * the distribution now includes Isabelle icons: see
  5415 lib/logo/isabelle-{small,tiny}.xpm;
  5416 
  5417 * isatool install - install binaries with absolute references to
  5418 ISABELLE_HOME/bin;
  5419 
  5420 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5421 
  5422 * print mode 'emacs' reserved for Isamode;
  5423 
  5424 * support multiple print (ast) translations per constant name;
  5425 
  5426 * theorems involving oracles are now printed with a suffixed [!];
  5427 
  5428 
  5429 *** HOL ***
  5430 
  5431 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5432 
  5433 * HOL/inductive package reorganized and improved: now supports mutual
  5434 definitions such as
  5435 
  5436   inductive EVEN ODD
  5437     intrs
  5438       null "0 : EVEN"
  5439       oddI "n : EVEN ==> Suc n : ODD"
  5440       evenI "n : ODD ==> Suc n : EVEN"
  5441 
  5442 new theorem list "elims" contains an elimination rule for each of the
  5443 recursive sets; inductive definitions now handle disjunctive premises
  5444 correctly (also ZF);
  5445 
  5446 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5447 "mutual_induct" no longer exists - the induction rule is always
  5448 contained in "induct";
  5449 
  5450 
  5451 * HOL/datatype package re-implemented and greatly improved: now
  5452 supports mutually recursive datatypes such as
  5453 
  5454   datatype
  5455     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5456             | SUM ('a aexp) ('a aexp)
  5457             | DIFF ('a aexp) ('a aexp)
  5458             | NUM 'a
  5459   and
  5460     'a bexp = LESS ('a aexp) ('a aexp)
  5461             | AND ('a bexp) ('a bexp)
  5462             | OR ('a bexp) ('a bexp)
  5463 
  5464 as well as indirectly recursive datatypes such as
  5465 
  5466   datatype
  5467     ('a, 'b) term = Var 'a
  5468                   | App 'b ((('a, 'b) term) list)
  5469 
  5470 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5471 induction on mutually / indirectly recursive datatypes.
  5472 
  5473 Primrec equations are now stored in theory and can be accessed via
  5474 <function_name>.simps.
  5475 
  5476 INCOMPATIBILITIES:
  5477 
  5478   - Theories using datatypes must now have theory Datatype as an
  5479     ancestor.
  5480   - The specific <typename>.induct_tac no longer exists - use the
  5481     generic induct_tac instead.
  5482   - natE has been renamed to nat.exhaust - use exhaust_tac
  5483     instead of res_inst_tac ... natE. Note that the variable
  5484     names in nat.exhaust differ from the names in natE, this
  5485     may cause some "fragile" proofs to fail.
  5486   - The theorems split_<typename>_case and split_<typename>_case_asm
  5487     have been renamed to <typename>.split and <typename>.split_asm.
  5488   - Since default sorts of type variables are now handled correctly,
  5489     some datatype definitions may have to be annotated with explicit
  5490     sort constraints.
  5491   - Primrec definitions no longer require function name and type
  5492     of recursive argument.
  5493 
  5494 Consider using isatool fixdatatype to adapt your theories and proof
  5495 scripts to the new package (backup your sources first!).
  5496 
  5497 
  5498 * HOL/record package: considerably improved implementation; now
  5499 includes concrete syntax for record types, terms, updates; theorems
  5500 for surjective pairing and splitting !!-bound record variables; proof
  5501 support is as follows:
  5502 
  5503   1) standard conversions (selectors or updates applied to record
  5504 constructor terms) are part of the standard simpset;
  5505 
  5506   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5507 made part of standard simpset and claset via addIffs;
  5508 
  5509   3) a tactic for record field splitting (record_split_tac) is part of
  5510 the standard claset (addSWrapper);
  5511 
  5512 To get a better idea about these rules you may retrieve them via
  5513 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5514 the name of your record type.
  5515 
  5516 The split tactic 3) conceptually simplifies by the following rule:
  5517 
  5518   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5519 
  5520 Thus any record variable that is bound by meta-all will automatically
  5521 blow up into some record constructor term, consequently the
  5522 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5523 solve record problems automatically.
  5524 
  5525 
  5526 * reorganized the main HOL image: HOL/Integ and String loaded by
  5527 default; theory Main includes everything;
  5528 
  5529 * automatic simplification of integer sums and comparisons, using cancellation;
  5530 
  5531 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5532 
  5533 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5534 
  5535 * many new identities for unions, intersections, set difference, etc.;
  5536 
  5537 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5538 called split_if, split_split, split_sum_case and split_nat_case (to go
  5539 with add/delsplits);
  5540 
  5541 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5542 (?x::unit) = (); this is made part of the default simpset, which COULD
  5543 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5544 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5545 unit_abs_eta_conv is added in order to counter the effect of
  5546 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5547 %u.f();
  5548 
  5549 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5550 makes more sense);
  5551 
  5552 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5553   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5554   disjointness reasoning but breaking a few old proofs.
  5555 
  5556 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5557 to 'converse' from 'inverse' (for compatibility with ZF and some
  5558 literature);
  5559 
  5560 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5561 the well-founded relation;
  5562 
  5563 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5564     Compl A.  The "Compl" syntax remains available as input syntax for this
  5565     release ONLY.
  5566 
  5567 * HOL/Update: new theory of function updates:
  5568     f(a:=b) == %x. if x=a then b else f x
  5569 may also be iterated as in f(a:=b,c:=d,...);
  5570 
  5571 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5572 
  5573 * HOL/List:
  5574   - new function list_update written xs[i:=v] that updates the i-th
  5575     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5576   - new function `upt' written [i..j(] which generates the list
  5577     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5578     bound write [i..j], which is a shorthand for [i..j+1(].
  5579   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5580 
  5581 * HOL/Arith:
  5582   - removed 'pred' (predecessor) function;
  5583   - generalized some theorems about n-1;
  5584   - many new laws about "div" and "mod";
  5585   - new laws about greatest common divisors (see theory ex/Primes);
  5586 
  5587 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5588 instead of "inverse";
  5589 
  5590 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5591   of the multiset ordering;
  5592 
  5593 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5594   (not included by default);
  5595 
  5596 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5597 
  5598 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5599   programs, i.e. different program variables may have different types.
  5600 
  5601 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5602   [previously, this check worked only if the rewrite rule was unconditional]
  5603   Now rew can involve either definitions or equalities (either == or =).
  5604 
  5605 
  5606 *** ZF ***
  5607 
  5608 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5609   only the theorems proved on ZF.ML;
  5610 
  5611 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5612   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5613   disjointness reasoning but breaking a few old proofs.
  5614 
  5615 * ZF/Update: new theory of function updates
  5616     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5617   may also be iterated as in f(a:=b,c:=d,...);
  5618 
  5619 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5620 
  5621 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5622   [previously, this check worked only if the rewrite rule was unconditional]
  5623   Now rew can involve either definitions or equalities (either == or =).
  5624 
  5625 * case_tac provided for compatibility with HOL
  5626     (like the old excluded_middle_tac, but with subgoals swapped)
  5627 
  5628 
  5629 *** Internal programming interfaces ***
  5630 
  5631 * Pure: several new basic modules made available for general use, see
  5632 also src/Pure/README;
  5633 
  5634 * improved the theory data mechanism to support encapsulation (data
  5635 kind name replaced by private Object.kind, acting as authorization
  5636 key); new type-safe user interface via functor TheoryDataFun; generic
  5637 print_data function becomes basically useless;
  5638 
  5639 * removed global_names compatibility flag -- all theory declarations
  5640 are qualified by default;
  5641 
  5642 * module Pure/Syntax now offers quote / antiquote translation
  5643 functions (useful for Hoare logic etc. with implicit dependencies);
  5644 see HOL/ex/Antiquote for an example use;
  5645 
  5646 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5647 cterm -> thm;
  5648 
  5649 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5650 subgoal;
  5651 
  5652 * Display.print_goals function moved to Locale.print_goals;
  5653 
  5654 * standard print function for goals supports current_goals_markers
  5655 variable for marking begin of proof, end of proof, start of goal; the
  5656 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5657 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5658 for example;
  5659 
  5660 
  5661 
  5662 New in Isabelle98 (January 1998)
  5663 --------------------------------
  5664 
  5665 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5666 
  5667 * changed lexical syntax of terms / types: dots made part of long
  5668 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5669 
  5670 * simpset (and claset) reference variable replaced by functions
  5671 simpset / simpset_ref;
  5672 
  5673 * no longer supports theory aliases (via merge) and non-trivial
  5674 implicit merge of thms' signatures;
  5675 
  5676 * most internal names of constants changed due to qualified names;
  5677 
  5678 * changed Pure/Sequence interface (see Pure/seq.ML);
  5679 
  5680 
  5681 *** General Changes ***
  5682 
  5683 * hierachically structured name spaces (for consts, types, axms, thms
  5684 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5685 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5686 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5687 long_names for fully qualified output names; NOTE: ML programs
  5688 (special tactics, packages etc.) referring to internal names may have
  5689 to be adapted to cope with fully qualified names; in case of severe
  5690 backward campatibility problems try setting 'global_names' at compile
  5691 time to have enrything declared within a flat name space; one may also
  5692 fine tune name declarations in theories via the 'global' and 'local'
  5693 section;
  5694 
  5695 * reimplemented the implicit simpset and claset using the new anytype
  5696 data filed in signatures; references simpset:simpset ref etc. are
  5697 replaced by functions simpset:unit->simpset and
  5698 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5699 to patch your ML files accordingly;
  5700 
  5701 * HTML output now includes theory graph data for display with Java
  5702 applet or isatool browser; data generated automatically via isatool
  5703 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5704 
  5705 * defs may now be conditional; improved rewrite_goals_tac to handle
  5706 conditional equations;
  5707 
  5708 * defs now admits additional type arguments, using TYPE('a) syntax;
  5709 
  5710 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5711 creates a new theory node; implicit merge of thms' signatures is
  5712 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5713 transfer:theory->thm->thm in (rare) cases;
  5714 
  5715 * improved handling of draft signatures / theories; draft thms (and
  5716 ctyps, cterms) are automatically promoted to real ones;
  5717 
  5718 * slightly changed interfaces for oracles: admit many per theory, named
  5719 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5720 
  5721 * print_goals: optional output of const types (set show_consts and
  5722 show_types);
  5723 
  5724 * improved output of warnings (###) and errors (***);
  5725 
  5726 * subgoal_tac displays a warning if the new subgoal has type variables;
  5727 
  5728 * removed old README and Makefiles;
  5729 
  5730 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5731 
  5732 * removed obsolete init_pps and init_database;
  5733 
  5734 * deleted the obsolete tactical STATE, which was declared by
  5735     fun STATE tacfun st = tacfun st st;
  5736 
  5737 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5738 (which abbreviates $HOME);
  5739 
  5740 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5741 use isatool fixseq to adapt your ML programs (this works for fully
  5742 qualified references to the Sequence structure only!);
  5743 
  5744 * use_thy no longer requires writable current directory; it always
  5745 reloads .ML *and* .thy file, if either one is out of date;
  5746 
  5747 
  5748 *** Classical Reasoner ***
  5749 
  5750 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5751 tactics that use classical reasoning to simplify a subgoal without
  5752 splitting it into several subgoals;
  5753 
  5754 * Safe_tac: like safe_tac but uses the default claset;
  5755 
  5756 
  5757 *** Simplifier ***
  5758 
  5759 * added simplification meta rules:
  5760     (asm_)(full_)simplify: simpset -> thm -> thm;
  5761 
  5762 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5763 logics (again);
  5764 
  5765 * added prems argument to simplification procedures;
  5766 
  5767 * HOL, FOL, ZF: added infix function `addsplits':
  5768   instead of `<simpset> setloop (split_tac <thms>)'
  5769   you can simply write `<simpset> addsplits <thms>'
  5770 
  5771 
  5772 *** Syntax ***
  5773 
  5774 * TYPE('a) syntax for type reflection terms;
  5775 
  5776 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5777 
  5778 * pretty printer: changed order of mixfix annotation preference (again!);
  5779 
  5780 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5781 
  5782 
  5783 *** HOL ***
  5784 
  5785 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5786   with `addloop' of the simplifier to faciliate case splitting in premises.
  5787 
  5788 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5789 
  5790 * HOL/Auth: new protocol proofs including some for the Internet
  5791   protocol TLS;
  5792 
  5793 * HOL/Map: new theory of `maps' a la VDM;
  5794 
  5795 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5796 cancelling out common nat summands from =, <, <= (in)equalities, or
  5797 differences; simplification procedures nat_cancel_factor for
  5798 cancelling common factor from =, <, <= (in)equalities over natural
  5799 sums; nat_cancel contains both kinds of procedures, it is installed by
  5800 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5801 
  5802 * HOL/simplifier: terms of the form
  5803   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5804   are rewritten to
  5805   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5806   and those of the form
  5807   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5808   are rewritten to
  5809   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5810 
  5811 * HOL/datatype
  5812   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5813 
  5814   P(t_case f1 ... fn x) =
  5815      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5816         ...
  5817        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5818      )
  5819 
  5820   and a theorem `split_t_case_asm' of the form
  5821 
  5822   P(t_case f1 ... fn x) =
  5823     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5824         ...
  5825        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5826      )
  5827   which can be added to a simpset via `addsplits'. The existing theorems
  5828   expand_list_case and expand_option_case have been renamed to
  5829   split_list_case and split_option_case.
  5830 
  5831 * HOL/Arithmetic:
  5832   - `pred n' is automatically converted to `n-1'.
  5833     Users are strongly encouraged not to use `pred' any longer,
  5834     because it will disappear altogether at some point.
  5835   - Users are strongly encouraged to write "0 < n" rather than
  5836     "n ~= 0". Theorems and proof tools have been modified towards this
  5837     `standard'.
  5838 
  5839 * HOL/Lists:
  5840   the function "set_of_list" has been renamed "set" (and its theorems too);
  5841   the function "nth" now takes its arguments in the reverse order and
  5842   has acquired the infix notation "!" as in "xs!n".
  5843 
  5844 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5845 
  5846 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5847   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5848 
  5849 * HOL/record: extensible records with schematic structural subtyping
  5850 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5851 still lacks various theorems and concrete record syntax;
  5852 
  5853 
  5854 *** HOLCF ***
  5855 
  5856 * removed "axioms" and "generated by" sections;
  5857 
  5858 * replaced "ops" section by extended "consts" section, which is capable of
  5859   handling the continuous function space "->" directly;
  5860 
  5861 * domain package:
  5862   . proves theorems immediately and stores them in the theory,
  5863   . creates hierachical name space,
  5864   . now uses normal mixfix annotations (instead of cinfix...),
  5865   . minor changes to some names and values (for consistency),
  5866   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5867   . separator between mutual domain defs: changed "," to "and",
  5868   . improved handling of sort constraints;  now they have to
  5869     appear on the left-hand side of the equations only;
  5870 
  5871 * fixed LAM <x,y,zs>.b syntax;
  5872 
  5873 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5874 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5875 
  5876 
  5877 *** FOL and ZF ***
  5878 
  5879 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5880   with `addloop' of the simplifier to faciliate case splitting in premises.
  5881 
  5882 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5883 in HOL, they strip ALL and --> from proved theorems;
  5884 
  5885 
  5886 
  5887 New in Isabelle94-8 (May 1997)
  5888 ------------------------------
  5889 
  5890 *** General Changes ***
  5891 
  5892 * new utilities to build / run / maintain Isabelle etc. (in parts
  5893 still somewhat experimental); old Makefiles etc. still functional;
  5894 
  5895 * new 'Isabelle System Manual';
  5896 
  5897 * INSTALL text, together with ./configure and ./build scripts;
  5898 
  5899 * reimplemented type inference for greater efficiency, better error
  5900 messages and clean internal interface;
  5901 
  5902 * prlim command for dealing with lots of subgoals (an easier way of
  5903 setting goals_limit);
  5904 
  5905 
  5906 *** Syntax ***
  5907 
  5908 * supports alternative (named) syntax tables (parser and pretty
  5909 printer); internal interface is provided by add_modesyntax(_i);
  5910 
  5911 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5912 be used in conjunction with the Isabelle symbol font; uses the
  5913 "symbols" syntax table;
  5914 
  5915 * added token_translation interface (may translate name tokens in
  5916 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5917 the current print_mode); IMPORTANT: user print translation functions
  5918 are responsible for marking newly introduced bounds
  5919 (Syntax.mark_boundT);
  5920 
  5921 * token translations for modes "xterm" and "xterm_color" that display
  5922 names in bold, underline etc. or colors (which requires a color
  5923 version of xterm);
  5924 
  5925 * infixes may now be declared with names independent of their syntax;
  5926 
  5927 * added typed_print_translation (like print_translation, but may
  5928 access type of constant);
  5929 
  5930 
  5931 *** Classical Reasoner ***
  5932 
  5933 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5934 some limitations.  Blast_tac...
  5935   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5936   + ignores elimination rules that don't have the correct format
  5937         (the conclusion MUST be a formula variable)
  5938   + ignores types, which can make HOL proofs fail
  5939   + rules must not require higher-order unification, e.g. apply_type in ZF
  5940     [message "Function Var's argument not a bound variable" relates to this]
  5941   + its proof strategy is more general but can actually be slower
  5942 
  5943 * substitution with equality assumptions no longer permutes other
  5944 assumptions;
  5945 
  5946 * minor changes in semantics of addafter (now called addaltern); renamed
  5947 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5948 (and access functions for it);
  5949 
  5950 * improved combination of classical reasoner and simplifier:
  5951   + functions for handling clasimpsets
  5952   + improvement of addss: now the simplifier is called _after_ the
  5953     safe steps.
  5954   + safe variant of addss called addSss: uses safe simplifications
  5955     _during_ the safe steps. It is more complete as it allows multiple
  5956     instantiations of unknowns (e.g. with slow_tac).
  5957 
  5958 *** Simplifier ***
  5959 
  5960 * added interface for simplification procedures (functions that
  5961 produce *proven* rewrite rules on the fly, depending on current
  5962 redex);
  5963 
  5964 * ordering on terms as parameter (used for ordered rewriting);
  5965 
  5966 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5967 
  5968 * the solver is now split into a safe and an unsafe part.
  5969 This should be invisible for the normal user, except that the
  5970 functions setsolver and addsolver have been renamed to setSolver and
  5971 addSolver; added safe_asm_full_simp_tac;
  5972 
  5973 
  5974 *** HOL ***
  5975 
  5976 * a generic induction tactic `induct_tac' which works for all datatypes and
  5977 also for type `nat';
  5978 
  5979 * a generic case distinction tactic `exhaust_tac' which works for all
  5980 datatypes and also for type `nat';
  5981 
  5982 * each datatype comes with a function `size';
  5983 
  5984 * patterns in case expressions allow tuple patterns as arguments to
  5985 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5986 
  5987 * primrec now also works with type nat;
  5988 
  5989 * recdef: a new declaration form, allows general recursive functions to be
  5990 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5991 
  5992 * the constant for negation has been renamed from "not" to "Not" to
  5993 harmonize with FOL, ZF, LK, etc.;
  5994 
  5995 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5996 infinite lists;
  5997 
  5998 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5999 
  6000 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6001 problems in commutative rings, using axiomatic type classes for + and *;
  6002 
  6003 * more examples in HOL/MiniML and HOL/Auth;
  6004 
  6005 * more default rewrite rules for quantifiers, union/intersection;
  6006 
  6007 * a new constant `arbitrary == @x.False';
  6008 
  6009 * HOLCF/IOA replaces old HOL/IOA;
  6010 
  6011 * HOLCF changes: derived all rules and arities
  6012   + axiomatic type classes instead of classes
  6013   + typedef instead of faking type definitions
  6014   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6015   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6016   + eliminated the types void, one, tr
  6017   + use unit lift and bool lift (with translations) instead of one and tr
  6018   + eliminated blift from Lift3.thy (use Def instead of blift)
  6019   all eliminated rules are derived as theorems --> no visible changes ;
  6020 
  6021 
  6022 *** ZF ***
  6023 
  6024 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6025 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6026 as ZF_cs addSIs [equalityI];
  6027 
  6028 
  6029 
  6030 New in Isabelle94-7 (November 96)
  6031 ---------------------------------
  6032 
  6033 * allowing negative levels (as offsets) in prlev and choplev;
  6034 
  6035 * super-linear speedup for large simplifications;
  6036 
  6037 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6038 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6039 FAIL); can suppress it using the command Delsimps (ex_simps @
  6040 all_simps); De Morgan laws are also now included, by default;
  6041 
  6042 * improved printing of ==>  :  ~:
  6043 
  6044 * new object-logic "Sequents" adds linear logic, while replacing LK
  6045 and Modal (thanks to Sara Kalvala);
  6046 
  6047 * HOL/Auth: correctness proofs for authentication protocols;
  6048 
  6049 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6050 examples on HOL/Auth);
  6051 
  6052 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6053 the rewriter and classical reasoner simultaneously;
  6054 
  6055 * function uresult no longer returns theorems in "standard" format;
  6056 regain previous version by: val uresult = standard o uresult;
  6057 
  6058 
  6059 
  6060 New in Isabelle94-6
  6061 -------------------
  6062 
  6063 * oracles -- these establish an interface between Isabelle and trusted
  6064 external reasoners, which may deliver results as theorems;
  6065 
  6066 * proof objects (in particular record all uses of oracles);
  6067 
  6068 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6069 
  6070 * "constdefs" section in theory files;
  6071 
  6072 * "primrec" section (HOL) no longer requires names;
  6073 
  6074 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6075 
  6076 
  6077 
  6078 New in Isabelle94-5
  6079 -------------------
  6080 
  6081 * reduced space requirements;
  6082 
  6083 * automatic HTML generation from theories;
  6084 
  6085 * theory files no longer require "..." (quotes) around most types;
  6086 
  6087 * new examples, including two proofs of the Church-Rosser theorem;
  6088 
  6089 * non-curried (1994) version of HOL is no longer distributed;
  6090 
  6091 
  6092 
  6093 New in Isabelle94-4
  6094 -------------------
  6095 
  6096 * greatly reduced space requirements;
  6097 
  6098 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6099 
  6100 * searchable theorem database (see the section "Retrieving theorems" on
  6101 page 8 of the Reference Manual);
  6102 
  6103 * new examples, including Grabczewski's monumental case study of the
  6104 Axiom of Choice;
  6105 
  6106 * The previous version of HOL renamed to Old_HOL;
  6107 
  6108 * The new version of HOL (previously called CHOL) uses a curried syntax
  6109 for functions.  Application looks like f a b instead of f(a,b);
  6110 
  6111 * Mutually recursive inductive definitions finally work in HOL;
  6112 
  6113 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6114 translates to the operator "split";
  6115 
  6116 
  6117 
  6118 New in Isabelle94-3
  6119 -------------------
  6120 
  6121 * new infix operator, addss, allowing the classical reasoner to
  6122 perform simplification at each step of its search.  Example:
  6123         fast_tac (cs addss ss)
  6124 
  6125 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6126 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6127 look like (a,b) instead of <a,b>;
  6128 
  6129 * PLEASE NOTE: CHOL will eventually replace HOL!
  6130 
  6131 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6132 It translates to the operator "split".  A new theory of integers is available;
  6133 
  6134 * In ZF, integer numerals now denote two's-complement binary integers.
  6135 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6136 
  6137 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6138 of the Axiom of Choice;
  6139 
  6140 
  6141 
  6142 New in Isabelle94-2
  6143 -------------------
  6144 
  6145 * Significantly faster resolution;
  6146 
  6147 * the different sections in a .thy file can now be mixed and repeated
  6148 freely;
  6149 
  6150 * Database of theorems for FOL, HOL and ZF.  New
  6151 commands including qed, qed_goal and bind_thm store theorems in the database.
  6152 
  6153 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6154 a given theory (thms_of), or find out what theory a theorem was proved in
  6155 (theory_of_thm);
  6156 
  6157 * Bugs fixed in the inductive definition and datatype packages;
  6158 
  6159 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6160 and HOL_dup_cs obsolete;
  6161 
  6162 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6163 have been removed;
  6164 
  6165 * Simpler definition of function space in ZF;
  6166 
  6167 * new results about cardinal and ordinal arithmetic in ZF;
  6168 
  6169 * 'subtype' facility in HOL for introducing new types as subsets of existing
  6170 types;
  6171 
  6172 :mode=text:wrap=hard:maxLineLen=72: