NEWS
author wenzelm
Wed Mar 11 23:59:34 2009 +0100 (2009-03-11)
changeset 30461 00323c45ea83
parent 30439 57c68b3af2ea
child 30530 03c120763ea8
child 30538 a77b7995062a
permissions -rw-r--r--
added 'local_setup' command;
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 * New command 'local_setup' is similar to 'setup', but operates on a
   202 local theory context.
   203 
   204 
   205 *** Document preparation ***
   206 
   207 * Antiquotation @{lemma} now imitates a regular terminal proof,
   208 demanding keyword 'by' and supporting the full method expression
   209 syntax just like the Isar command 'by'.
   210 
   211 
   212 *** HOL ***
   213 
   214 * Theory Library/Diagonalize.thy provides constructive version of
   215 Cantor's first diagonalization argument.
   216 
   217 * New predicate "strict_mono" classifies strict functions on partial orders.
   218 With strict functions on linear orders, reasoning about (in)equalities is
   219 facilitated by theorems "strict_mono_eq", "strict_mono_less_eq" and "strict_mono_less".
   220 
   221 * Some set operations are now proper qualified constants with authentic syntax.
   222 INCOMPATIBILITY:
   223 
   224     op Int ~>   Set.Int
   225     op Un ~>    Set.Un
   226     INTER ~>    Set.INTER
   227     UNION ~>    Set.UNION
   228     Inter ~>    Set.Inter
   229     Union ~>    Set.Union
   230     {} ~>       Set.empty
   231     UNIV ~>     Set.UNIV
   232 
   233 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in theory
   234 Set.
   235 
   236 * Auxiliary class "itself" has disappeared -- classes without any parameter
   237 are treated as expected by the 'class' command.
   238 
   239 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   240 
   241 * Common decision procedures (Cooper, MIR, Ferrack, Approximation, Dense_Linear_Order)
   242 now in directory HOL/Decision_Procs.
   243 
   244 * Theory HOL/Decisioin_Procs/Approximation.thy provides the new proof method
   245 "approximation".  It proves formulas on real values by using interval arithmetic.
   246 In the formulas are also the transcendental functions sin, cos, tan, atan, ln,
   247 exp and the constant pi are allowed. For examples see
   248 HOL/Descision_Procs/ex/Approximation_Ex.thy.
   249 
   250 * Theory "Reflection" now resides in HOL/Library.
   251 
   252 * Entry point to Word library now simply named "Word".  INCOMPATIBILITY.
   253 
   254 * Made source layout more coherent with logical distribution
   255 structure:
   256 
   257     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   258     src/HOL/Library/Code_Message.thy ~> src/HOL/
   259     src/HOL/Library/GCD.thy ~> src/HOL/
   260     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   261     src/HOL/Library/Parity.thy ~> src/HOL/
   262     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   263     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   264     src/HOL/Real/Lubs.thy ~> src/HOL/
   265     src/HOL/Real/PReal.thy ~> src/HOL/
   266     src/HOL/Real/Rational.thy ~> src/HOL/
   267     src/HOL/Real/RComplete.thy ~> src/HOL/
   268     src/HOL/Real/RealDef.thy ~> src/HOL/
   269     src/HOL/Real/RealPow.thy ~> src/HOL/
   270     src/HOL/Real/Real.thy ~> src/HOL/
   271     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   272     src/HOL/Complex/Complex.thy ~> src/HOL/
   273     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   274     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   275     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   276     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   277     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   278     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   279     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   280     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   281     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   282     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   283     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   284     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   285     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   286     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   287     src/HOL/Real/Float ~> src/HOL/Library/
   288     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   289     src/HOL/Real/RealVector.thy ~> src/HOL/
   290 
   291     src/HOL/arith_data.ML ~> src/HOL/Tools
   292     src/HOL/hologic.ML ~> src/HOL/Tools
   293     src/HOL/simpdata.ML ~> src/HOL/Tools
   294     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   295     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   296     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   297     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   298     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   299     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   300     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   301 
   302     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   303     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   304     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   305     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   306     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   307     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   308 
   309 * If methods "eval" and "evaluation" encounter a structured proof state
   310 with !!/==>, only the conclusion is evaluated to True (if possible),
   311 avoiding strange error messages.
   312 
   313 * Simplifier: simproc for let expressions now unfolds if bound variable
   314 occurs at most once in let expression body.  INCOMPATIBILITY.
   315 
   316 * New classes "top" and "bot" with corresponding operations "top" and "bot"
   317 in theory Orderings;  instantiation of class "complete_lattice" requires
   318 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   319 
   320 * Changed definition lemma "less_fun_def" in order to provide an instance
   321 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   322 
   323 * Unified theorem tables for both code code generators.  Thus
   324 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   325 
   326 * Constants "undefined" and "default" replace "arbitrary".  Usually
   327 "undefined" is the right choice to replace "arbitrary", though logically
   328 there is no difference.  INCOMPATIBILITY.
   329 
   330 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   331 Posix processes.  Avoids potentially expensive forking of the ML
   332 process.  New thread-based implementation also works on non-Unix
   333 platforms (Cygwin).  Provers are no longer hardwired, but defined
   334 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   335 commands are covered in the isar-ref manual.
   336 
   337 * Wrapper scripts for remote SystemOnTPTP service allows to use
   338 sledgehammer without local ATP installation (Vampire etc.).  See also
   339 ISABELLE_HOME/contrib/SystemOnTPTP and the VAMPIRE_HOME setting
   340 variable.  Other provers may be included via suitable ML wrappers, see
   341 also src/HOL/ATP_Linkup.thy.
   342 
   343 * Normalization by evaluation now allows non-leftlinear equations.
   344 Declare with attribute [code nbe].
   345 
   346 * Command "value" now integrates different evaluation
   347 mechanisms.  The result of the first successful evaluation mechanism
   348 is printed.  In square brackets a particular named evaluation
   349 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   350 further src/HOL/ex/Eval_Examples.thy.
   351 
   352 * New method "sizechange" to automate termination proofs using (a
   353 modification of) the size-change principle. Requires SAT solver. See
   354 src/HOL/ex/Termination.thy for examples.
   355 
   356 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   357 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   358 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   359 
   360 * HOL/Orderings: added class "preorder" as superclass of "order".
   361 INCOMPATIBILITY: Instantiation proofs for order, linorder
   362 etc. slightly changed.  Some theorems named order_class.* now named
   363 preorder_class.*.
   364 
   365 * HOL/Relation:
   366 Renamed "refl" to "refl_on", "reflexive" to "refl, "diag" to "Id_on".
   367 
   368 * HOL/Finite_Set: added a new fold combinator of type
   369   ('a => 'b => 'b) => 'b => 'a set => 'b
   370 Occasionally this is more convenient than the old fold combinator which is
   371 now defined in terms of the new one and renamed to fold_image.
   372 
   373 * HOL/Ring_and_Field and HOL/OrderedGroup: The lemmas "group_simps" and
   374 "ring_simps" have been replaced by "algebra_simps" (which can be extended with
   375 further lemmas!). At the moment both still exist but the former will disappear
   376 at some point.
   377 
   378 * HOL/Power: Lemma power_Suc is now declared as a simp rule in class
   379 recpower.  Type-specific simp rules for various recpower types have
   380 been removed.  INCOMPATIBILITY.  Rename old lemmas as follows:
   381 
   382 rat_power_0    -> power_0
   383 rat_power_Suc  -> power_Suc
   384 realpow_0      -> power_0
   385 realpow_Suc    -> power_Suc
   386 complexpow_0   -> power_0
   387 complexpow_Suc -> power_Suc
   388 power_poly_0   -> power_0
   389 power_poly_Suc -> power_Suc
   390 
   391 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   392 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   393 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   394 of lemmas from Divides has been generalized from nat to class
   395 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   396 renames resulting from duplicate elimination:
   397 
   398     dvd_def_mod ~>          dvd_eq_mod_eq_0
   399     zero_dvd_iff ~>         dvd_0_left_iff
   400     dvd_0 ~>                dvd_0_right
   401     DIVISION_BY_ZERO_DIV ~> div_by_0
   402     DIVISION_BY_ZERO_MOD ~> mod_by_0
   403     mult_div ~>             div_mult_self2_is_id
   404     mult_mod ~>             mod_mult_self2_is_0
   405 
   406 * HOL/IntDiv: removed many lemmas that are instances of class-based
   407 generalizations (from Divides and Ring_and_Field).
   408 INCOMPATIBILITY. Rename old lemmas as follows:
   409 
   410 dvd_diff               -> nat_dvd_diff
   411 dvd_zminus_iff         -> dvd_minus_iff
   412 mod_add1_eq            -> mod_add_eq
   413 mod_mult1_eq           -> mod_mult_right_eq
   414 mod_mult1_eq'          -> mod_mult_left_eq
   415 mod_mult_distrib_mod   -> mod_mult_eq
   416 nat_mod_add_left_eq    -> mod_add_left_eq
   417 nat_mod_add_right_eq   -> mod_add_right_eq
   418 nat_mod_div_trivial    -> mod_div_trivial
   419 nat_mod_mod_trivial    -> mod_mod_trivial
   420 zdiv_zadd_self1        -> div_add_self1
   421 zdiv_zadd_self2        -> div_add_self2
   422 zdiv_zmult_self1       -> div_mult_self2_is_id
   423 zdiv_zmult_self2       -> div_mult_self1_is_id
   424 zdvd_triv_left         -> dvd_triv_left
   425 zdvd_triv_right        -> dvd_triv_right
   426 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   427 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   428 zmod_zadd_left_eq      -> mod_add_left_eq
   429 zmod_zadd_right_eq     -> mod_add_right_eq
   430 zmod_zadd_self1        -> mod_add_self1
   431 zmod_zadd_self2        -> mod_add_self2
   432 zmod_zadd1_eq          -> mod_add_eq
   433 zmod_zdiff1_eq         -> mod_diff_eq
   434 zmod_zdvd_zmod         -> mod_mod_cancel
   435 zmod_zmod_cancel       -> mod_mod_cancel
   436 zmod_zmult_self1       -> mod_mult_self2_is_0
   437 zmod_zmult_self2       -> mod_mult_self1_is_0
   438 zmod_1                 -> mod_by_1
   439 zdiv_1                 -> div_by_1
   440 zdvd_abs1              -> abs_dvd_iff
   441 zdvd_abs2              -> dvd_abs_iff
   442 zdvd_refl              -> dvd_refl
   443 zdvd_trans             -> dvd_trans
   444 zdvd_zadd              -> dvd_add
   445 zdvd_zdiff             -> dvd_diff
   446 zdvd_zminus_iff        -> dvd_minus_iff
   447 zdvd_zminus2_iff       -> minus_dvd_iff
   448 zdvd_zmultD            -> dvd_mult_right
   449 zdvd_zmultD2           -> dvd_mult_left
   450 zdvd_zmult_mono        -> mult_dvd_mono
   451 zdvd_0_right           -> dvd_0_right
   452 zdvd_0_left            -> dvd_0_left_iff
   453 zdvd_1_left            -> one_dvd
   454 zminus_dvd_iff         -> minus_dvd_iff
   455 
   456 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   457 zlcm (for int); carried together from various gcd/lcm developements in
   458 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   459 corresponding theorems renamed accordingly.  INCOMPATIBILITY.  To
   460 recover tupled syntax, use syntax declarations like:
   461 
   462     hide (open) const gcd
   463     abbreviation gcd where
   464       "gcd == (%(a, b). GCD.gcd a b)"
   465     notation (output)
   466       GCD.gcd ("gcd '(_, _')")
   467 
   468 (analogously for lcm, zgcd, zlcm).
   469 
   470 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   471 
   472 * The real numbers offer decimal input syntax: 12.34 is translated into
   473   1234/10^2. This translation is not reversed upon output.
   474 
   475 * New ML antiquotation @{code}: takes constant as argument, generates
   476 corresponding code in background and inserts name of the corresponding
   477 resulting ML value/function/datatype constructor binding in place.
   478 All occurrences of @{code} with a single ML block are generated
   479 simultaneously.  Provides a generic and safe interface for
   480 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   481 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   482 application.  In future you ought refrain from ad-hoc compiling
   483 generated SML code on the ML toplevel.  Note that (for technical
   484 reasons) @{code} cannot refer to constants for which user-defined
   485 serializations are set.  Refer to the corresponding ML counterpart
   486 directly in that cases.
   487 
   488 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   489 Complex_Main.thy remain as they are.
   490 
   491 * New image HOL-Plain provides a minimal HOL with the most important
   492 tools available (inductive, datatype, primrec, ...).  By convention
   493 the corresponding theory Plain should be ancestor of every further
   494 (library) theory.  Some library theories now have ancestor Plain
   495 (instead of Main), thus theory Main occasionally has to be imported
   496 explicitly.
   497 
   498 * The metis method now fails in the usual manner, rather than raising
   499 an exception, if it determines that it cannot prove the theorem.
   500 
   501 * The metis method no longer fails because the theorem is too trivial
   502 (contains the empty clause).
   503 
   504 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   505 as the structured Isar versions "cases" and "induct", cf. the
   506 corresponding "cases" and "induct" attributes.  Mutual induction rules
   507 are now presented as a list of individual projections
   508 (e.g. foo_bar.inducts for types foo and bar); the old format with
   509 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   510 rare situations a different rule is selected --- notably nested tuple
   511 elimination instead of former prod.exhaust: use explicit (case_tac t
   512 rule: prod.exhaust) here.
   513 
   514 * Attributes "cases", "induct", "coinduct" support "del" option.
   515 
   516 * Removed fact "case_split_thm", which duplicates "case_split".
   517 
   518 * Command 'rep_datatype': instead of theorem names the command now
   519 takes a list of terms denoting the constructors of the type to be
   520 represented as datatype.  The characteristic theorems have to be
   521 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   522 have disappeared in favour of existing ones:
   523 
   524     unit_induct                 ~> unit.induct
   525     prod_induct                 ~> prod.induct
   526     sum_induct                  ~> sum.induct
   527     Suc_Suc_eq                  ~> nat.inject
   528     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   529 
   530 * The option datatype has been moved to a new theory HOL/Option.thy.
   531 Renamed option_map to Option.map, and o2s to Option.set.
   532 
   533 * Library/Nat_Infinity: added addition, numeral syntax and more
   534 instantiations for algebraic structures.  Removed some duplicate
   535 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   536 
   537 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   538 menu.
   539 
   540 * Linear arithmetic now ignores all inequalities when
   541 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   542 
   543 
   544 *** HOL-Algebra ***
   545 
   546 * New locales for orders and lattices where the equivalence relation
   547 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   548 locales use a record structure with field eq for the equivalence.
   549 
   550 * New theory of factorial domains.
   551 
   552 * Units_l_inv and Units_r_inv are now simprules by default.
   553 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   554 and/or r_inv will now also require deletion of these lemmas.
   555 
   556 * Renamed the following theorems.  INCOMPATIBILITY.
   557 UpperD ~> Upper_memD
   558 LowerD ~> Lower_memD
   559 least_carrier ~> least_closed
   560 greatest_carrier ~> greatest_closed
   561 greatest_Lower_above ~> greatest_Lower_below
   562 one_zero ~> carrier_one_zero
   563 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   564 
   565 
   566 *** HOL-NSA ***
   567 
   568 * Created new image HOL-NSA, containing theories of nonstandard
   569 analysis which were previously part of HOL-Complex.  Entry point
   570 Hyperreal.thy remains valid, but theories formerly using
   571 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   572 
   573 
   574 *** ZF ***
   575 
   576 * Proof of Zorn's Lemma for partial orders.
   577 
   578 
   579 *** HOLCF ***
   580 
   581 * Reimplemented the simplification procedure for proving continuity
   582 subgoals.  The new simproc is extensible; users can declare additional
   583 continuity introduction rules with the attribute [cont2cont].
   584 
   585 * The continuity simproc now uses a different introduction rule for
   586 solving continuity subgoals on terms with lambda abstractions.  In
   587 some rare cases the new simproc may fail to solve subgoals that the
   588 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   589 Potential INCOMPATIBILITY.
   590 
   591 * The syntax of the fixrec package has changed.  The specification
   592 syntax now conforms in style to definition, primrec, function, etc.
   593 See HOLCF/ex/Fixrec_ex.thy for examples.  INCOMPATIBILITY.
   594 
   595 
   596 *** ML ***
   597 
   598 * High-level support for concurrent ML programming, see
   599 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   600 particularly convenient to organize independent functional
   601 computations.  The concept of "synchronized variables" provides a
   602 higher-order interface for components with shared state, avoiding the
   603 delicate details of mutexes and condition variables.  [Poly/ML 5.2.1
   604 or later]
   605 
   606 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   607 to 'a -> thm, while results are always tagged with an authentic oracle
   608 name.  The Isar command 'oracle' is now polymorphic, no argument type
   609 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   610 accordingly.  Note that extra performance may be gained by producing
   611 the cterm carefully, avoiding slow Thm.cterm_of.
   612 
   613 * ML bindings produced via Isar commands are stored within the Isar
   614 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   615 become thread-safe and work with undo as expected (concerning
   616 top-level bindings, not side-effects on global references).
   617 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   618 compiler at runtime; really global bindings need to be given outside a
   619 theory. [Poly/ML 5.2 or later]
   620 
   621 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   622 context. Top-level ML bindings are stored within the proof context in
   623 a purely sequential fashion, disregarding the nested proof structure.
   624 ML bindings introduced by 'ML_prf' are discarded at the end of the
   625 proof.  [Poly/ML 5.2 or later]
   626 
   627 * Generic Toplevel.add_hook interface allows to analyze the result of
   628 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   629 for theorem dependency output of transactions resulting in a new
   630 theory state.
   631 
   632 * More systematic treatment of long names, abstract name bindings, and
   633 name space operations.  Basic operations on qualified names have been
   634 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   635 Long_Name.append.  Old type bstring has been mostly replaced by
   636 abstract type binding (see structure Binding), which supports precise
   637 qualification (by packages and local theory targets), as well as
   638 proper tracking of source positions.  INCOMPATIBILITY, need to wrap
   639 old bstring values into Binding.name, or better pass through abstract
   640 bindings everywhere.  See further src/Pure/General/long_name.ML,
   641 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   642 
   643 * Simplified interface for defining document antiquotations via
   644 ThyOutput.antiquotation, ThyOutput.output, and optionally
   645 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   646 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   647 examples.
   648 
   649 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   650 LocalTheory.note etc.) now refer to the *full* internal name, not the
   651 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   652 
   653 * Rules and tactics that read instantiations (read_instantiate,
   654 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   655 context, which is required for parsing and type-checking.  Moreover,
   656 the variables are specified as plain indexnames, not string encodings
   657 thereof.  INCOMPATIBILITY.
   658 
   659 * Disposed old type and term read functions (Sign.read_def_typ,
   660 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   661 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   662 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   663 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   664 resort for legacy applications.
   665 
   666 * Antiquotations: block-structured compilation context indicated by
   667 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   668 
   669   @{let ?pat = term}                      - term abbreviation (HO matching)
   670   @{note name = fact}                     - fact abbreviation
   671   @{thm fact}                             - singleton fact (with attributes)
   672   @{thms fact}                            - general fact (with attributes)
   673   @{lemma prop by method}                 - singleton goal
   674   @{lemma prop by meth1 meth2}            - singleton goal
   675   @{lemma prop1 ... propN by method}      - general goal
   676   @{lemma prop1 ... propN by meth1 meth2} - general goal
   677   @{lemma (open) ...}                     - open derivation
   678 
   679 
   680 *** System ***
   681 
   682 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   683 Poly/ML 5.2.1 or later.
   684 
   685 * The Isabelle "emacs" tool provides a specific interface to invoke
   686 Proof General / Emacs, with more explicit failure if that is not
   687 installed (the old isabelle-interface script silently falls back on
   688 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   689 installation location of the Proof General distribution.
   690 
   691 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   692 the Isabelle process into a JVM/Scala application.  See
   693 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   694 process wrapper has been discontinued.)
   695 
   696 * Status messages (with exact source position information) are
   697 emitted, if proper markup print mode is enabled.  This allows
   698 user-interface components to provide detailed feedback on internal
   699 prover operations.
   700 
   701 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   702 
   703 
   704 
   705 New in Isabelle2008 (June 2008)
   706 -------------------------------
   707 
   708 *** General ***
   709 
   710 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   711 and updated, with formally checked references as hyperlinks.
   712 
   713 * Theory loader: use_thy (and similar operations) no longer set the
   714 implicit ML context, which was occasionally hard to predict and in
   715 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   716 provides a proper context already.
   717 
   718 * Theory loader: old-style ML proof scripts being *attached* to a thy
   719 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   720 'use' within a theory file will do the job.
   721 
   722 * Name space merge now observes canonical order, i.e. the second space
   723 is inserted into the first one, while existing entries in the first
   724 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   725 swap theory imports.
   726 
   727 * Syntax: symbol \<chi> is now considered a letter.  Potential
   728 INCOMPATIBILITY in identifier syntax etc.
   729 
   730 * Outer syntax: string tokens no longer admit escaped white space,
   731 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   732 white space without escapes.
   733 
   734 * Outer syntax: string tokens may contain arbitrary character codes
   735 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   736 "foo_bar".
   737 
   738 
   739 *** Pure ***
   740 
   741 * Context-dependent token translations.  Default setup reverts locally
   742 fixed variables, and adds hilite markup for undeclared frees.
   743 
   744 * Unused theorems can be found using the new command 'unused_thms'.
   745 There are three ways of invoking it:
   746 
   747 (1) unused_thms
   748      Only finds unused theorems in the current theory.
   749 
   750 (2) unused_thms thy_1 ... thy_n -
   751      Finds unused theorems in the current theory and all of its ancestors,
   752      excluding the theories thy_1 ... thy_n and all of their ancestors.
   753 
   754 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   755      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   756      their ancestors, excluding the theories thy_1 ... thy_n and all of
   757      their ancestors.
   758 
   759 In order to increase the readability of the list produced by
   760 unused_thms, theorems that have been created by a particular instance
   761 of a theory command such as 'inductive' or 'function' are considered
   762 to belong to the same "group", meaning that if at least one theorem in
   763 this group is used, the other theorems in the same group are no longer
   764 reported as unused.  Moreover, if all theorems in the group are
   765 unused, only one theorem in the group is displayed.
   766 
   767 Note that proof objects have to be switched on in order for
   768 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   769 usually the case when using Proof General with the default settings).
   770 
   771 * Authentic naming of facts disallows ad-hoc overwriting of previous
   772 theorems within the same name space.  INCOMPATIBILITY, need to remove
   773 duplicate fact bindings, or even accidental fact duplications.  Note
   774 that tools may maintain dynamically scoped facts systematically, using
   775 PureThy.add_thms_dynamic.
   776 
   777 * Command 'hide' now allows to hide from "fact" name space as well.
   778 
   779 * Eliminated destructive theorem database, simpset, claset, and
   780 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   781 update of theories within ML code.
   782 
   783 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   784 INCOMPATIBILITY, object-logics depending on former Pure require
   785 additional setup PureThy.old_appl_syntax_setup; object-logics
   786 depending on former CPure need to refer to Pure.
   787 
   788 * Commands 'use' and 'ML' are now purely functional, operating on
   789 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   790 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   791 INCOMPATIBILITY.
   792 
   793 * Command 'setup': discontinued implicit version with ML reference.
   794 
   795 * Instantiation target allows for simultaneous specification of class
   796 instance operations together with an instantiation proof.
   797 Type-checking phase allows to refer to class operations uniformly.
   798 See src/HOL/Complex/Complex.thy for an Isar example and
   799 src/HOL/Library/Eval.thy for an ML example.
   800 
   801 * Indexing of literal facts: be more serious about including only
   802 facts from the visible specification/proof context, but not the
   803 background context (locale etc.).  Affects `prop` notation and method
   804 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   805 situations.
   806 
   807 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   808 "(open)" option, which used to expose internal bound variables to the
   809 proof text.
   810 
   811 * Isar statements: removed obsolete case "rule_context".
   812 INCOMPATIBILITY, better use explicit fixes/assumes.
   813 
   814 * Locale proofs: default proof step now includes 'unfold_locales';
   815 hence 'proof' without argument may be used to unfold locale
   816 predicates.
   817 
   818 
   819 *** Document preparation ***
   820 
   821 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   822 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   823 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   824 spot); renamed link color from "darkblue" to "linkcolor" (default
   825 value unchanged, can be redefined via \definecolor); no longer sets
   826 "a4paper" option (unnecessary or even intrusive).
   827 
   828 * Antiquotation @{lemma A method} proves proposition A by the given
   829 method (either a method name or a method name plus (optional) method
   830 arguments in parentheses) and prints A just like @{prop A}.
   831 
   832 
   833 *** HOL ***
   834 
   835 * New primrec package.  Specification syntax conforms in style to
   836 definition/function/....  No separate induction rule is provided.  The
   837 "primrec" command distinguishes old-style and new-style specifications
   838 by syntax.  The former primrec package is now named OldPrimrecPackage.
   839 When adjusting theories, beware: constants stemming from new-style
   840 primrec specifications have authentic syntax.
   841 
   842 * Metis prover is now an order of magnitude faster, and also works
   843 with multithreading.
   844 
   845 * Metis: the maximum number of clauses that can be produced from a
   846 theorem is now given by the attribute max_clauses.  Theorems that
   847 exceed this number are ignored, with a warning printed.
   848 
   849 * Sledgehammer no longer produces structured proofs by default. To
   850 enable, declare [[sledgehammer_full = true]].  Attributes
   851 reconstruction_modulus, reconstruction_sorts renamed
   852 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   853 
   854 * Method "induct_scheme" derives user-specified induction rules
   855 from well-founded induction and completeness of patterns. This factors
   856 out some operations that are done internally by the function package
   857 and makes them available separately.  See
   858 src/HOL/ex/Induction_Scheme.thy for examples.
   859 
   860 * More flexible generation of measure functions for termination
   861 proofs: Measure functions can be declared by proving a rule of the
   862 form "is_measure f" and giving it the [measure_function] attribute.
   863 The "is_measure" predicate is logically meaningless (always true), and
   864 just guides the heuristic.  To find suitable measure functions, the
   865 termination prover sets up the goal "is_measure ?f" of the appropriate
   866 type and generates all solutions by prolog-style backwards proof using
   867 the declared rules.
   868 
   869 This setup also deals with rules like 
   870 
   871   "is_measure f ==> is_measure (list_size f)"
   872 
   873 which accommodates nested datatypes that recurse through lists.
   874 Similar rules are predeclared for products and option types.
   875 
   876 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   877 
   878   INCOMPATIBILITIES:
   879 
   880   - Definitions of overloaded constants on sets have to be replaced by
   881     definitions on => and bool.
   882 
   883   - Some definitions of overloaded operators on sets can now be proved
   884     using the definitions of the operators on => and bool.  Therefore,
   885     the following theorems have been renamed:
   886 
   887       subset_def   -> subset_eq
   888       psubset_def  -> psubset_eq
   889       set_diff_def -> set_diff_eq
   890       Compl_def    -> Compl_eq
   891       Sup_set_def  -> Sup_set_eq
   892       Inf_set_def  -> Inf_set_eq
   893       sup_set_def  -> sup_set_eq
   894       inf_set_def  -> inf_set_eq
   895 
   896   - Due to the incompleteness of the HO unification algorithm, some
   897     rules such as subst may require manual instantiation, if some of
   898     the unknowns in the rule is a set.
   899 
   900   - Higher order unification and forward proofs:
   901     The proof pattern
   902 
   903       have "P (S::'a set)" <...>
   904       then have "EX S. P S" ..
   905 
   906     no longer works (due to the incompleteness of the HO unification
   907     algorithm) and must be replaced by the pattern
   908 
   909       have "EX S. P S"
   910       proof
   911         show "P S" <...>
   912       qed
   913 
   914   - Calculational reasoning with subst (or similar rules):
   915     The proof pattern
   916 
   917       have "P (S::'a set)" <...>
   918       also have "S = T" <...>
   919       finally have "P T" .
   920 
   921     no longer works (for similar reasons as the previous example) and
   922     must be replaced by something like
   923 
   924       have "P (S::'a set)" <...>
   925       moreover have "S = T" <...>
   926       ultimately have "P T" by simp
   927 
   928   - Tactics or packages written in ML code:
   929     Code performing pattern matching on types via
   930 
   931       Type ("set", [T]) => ...
   932 
   933     must be rewritten. Moreover, functions like strip_type or
   934     binder_types no longer return the right value when applied to a
   935     type of the form
   936 
   937       T1 => ... => Tn => U => bool
   938 
   939     rather than
   940 
   941       T1 => ... => Tn => U set
   942 
   943 * Merged theories Wellfounded_Recursion, Accessible_Part and
   944 Wellfounded_Relations to theory Wellfounded.
   945 
   946 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   947 
   948 * Class finite no longer treats UNIV as class parameter.  Use class
   949 enum from theory Library/Enum instead to achieve a similar effect.
   950 INCOMPATIBILITY.
   951 
   952 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   953 and "Cons".  INCOMPATIBILITY.
   954 
   955 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   956 Potential INCOMPATIBILITY.
   957 
   958 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   959 injective_fst_snd removed, use split_eta and prod_eqI instead.
   960 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   961 
   962 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   963 the same name in theory Orderings:
   964 
   965   less_trans
   966   less_linear
   967   le_imp_less_or_eq
   968   le_less_trans
   969   less_le_trans
   970   less_not_sym
   971   less_asym
   972 
   973 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   974 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   975 and different variable names.
   976 
   977 * Library/Option_ord.thy: Canonical order on option type.
   978 
   979 * Library/RBT.thy: Red-black trees, an efficient implementation of
   980 finite maps.
   981 
   982 * Library/Countable.thy: Type class for countable types.
   983 
   984 * Theory Int: The representation of numerals has changed.  The infix
   985 operator BIT and the bit datatype with constructors B0 and B1 have
   986 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   987 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   988 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   989 accordingly.
   990 
   991 * Theory Nat: definition of <= and < on natural numbers no longer
   992 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   993 le_def and less_def have disappeared.  Consider lemmas not_less
   994 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   995 
   996 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   997 (whose purpose mainly is for various fold_set functionals) have been
   998 abandoned in favor of the existing algebraic classes
   999 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1000 lower_semilattice (resp. upper_semilattice) and linorder.
  1001 INCOMPATIBILITY.
  1002 
  1003 * Theory Transitive_Closure: induct and cases rules now declare proper
  1004 case_names ("base" and "step").  INCOMPATIBILITY.
  1005 
  1006 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1007 lattices.  The form set-specific version is available as
  1008 Inductive.lfp_ordinal_induct_set.
  1009 
  1010 * Renamed theorems "power.simps" to "power_int.simps".
  1011 INCOMPATIBILITY.
  1012 
  1013 * Class semiring_div provides basic abstract properties of semirings
  1014 with division and modulo operations.  Subsumes former class dvd_mod.
  1015 
  1016 * Merged theories IntDef, Numeral and IntArith into unified theory
  1017 Int.  INCOMPATIBILITY.
  1018 
  1019 * Theory Library/Code_Index: type "index" now represents natural
  1020 numbers rather than integers.  INCOMPATIBILITY.
  1021 
  1022 * New class "uminus" with operation "uminus" (split of from class
  1023 "minus" which now only has operation "minus", binary).
  1024 INCOMPATIBILITY.
  1025 
  1026 * Constants "card", "internal_split", "option_map" now with authentic
  1027 syntax.  INCOMPATIBILITY.
  1028 
  1029 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1030 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1031 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1032 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1033 Sup_set_def, le_def, less_def, option_map_def now with object
  1034 equality.  INCOMPATIBILITY.
  1035 
  1036 * Records. Removed K_record, and replaced it by pure lambda term
  1037 %x. c. The simplifier setup is now more robust against eta expansion.
  1038 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1039 
  1040 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1041 
  1042 * Library/ListVector: new theory of arithmetic vector operations.
  1043 
  1044 * Library/Order_Relation: new theory of various orderings as sets of
  1045 pairs.  Defines preorders, partial orders, linear orders and
  1046 well-orders on sets and on types.
  1047 
  1048 
  1049 *** ZF ***
  1050 
  1051 * Renamed some theories to allow to loading both ZF and HOL in the
  1052 same session:
  1053 
  1054   Datatype  -> Datatype_ZF
  1055   Inductive -> Inductive_ZF
  1056   Int       -> Int_ZF
  1057   IntDiv    -> IntDiv_ZF
  1058   Nat       -> Nat_ZF
  1059   List      -> List_ZF
  1060   Main      -> Main_ZF
  1061 
  1062 INCOMPATIBILITY: ZF theories that import individual theories below
  1063 Main might need to be adapted.  Regular theory Main is still
  1064 available, as trivial extension of Main_ZF.
  1065 
  1066 
  1067 *** ML ***
  1068 
  1069 * ML within Isar: antiquotation @{const name} or @{const
  1070 name(typargs)} produces statically-checked Const term.
  1071 
  1072 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1073 (of the same name).  Removed obsolete print command.
  1074 
  1075 * Removed obsolete "use_legacy_bindings" function.
  1076 
  1077 * The ``print mode'' is now a thread-local value derived from a global
  1078 template (the former print_mode reference), thus access becomes
  1079 non-critical.  The global print_mode reference is for session
  1080 management only; user-code should use print_mode_value,
  1081 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1082 
  1083 * Functions system/system_out provide a robust way to invoke external
  1084 shell commands, with propagation of interrupts (requires Poly/ML
  1085 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1086 
  1087 
  1088 *** System ***
  1089 
  1090 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1091 in accordance with Proof General 3.7, which prefers GNU emacs.
  1092 
  1093 * isatool tty runs Isabelle process with plain tty interaction;
  1094 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1095 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1096 
  1097 * isatool browser now works with Cygwin as well, using general
  1098 "javapath" function defined in Isabelle process environment.
  1099 
  1100 * YXML notation provides a simple and efficient alternative to
  1101 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1102 isatool yxml as described in the Isabelle system manual.
  1103 
  1104 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1105 provides general wrapper for managing an Isabelle process in a robust
  1106 fashion, with ``cooked'' output from stdin/stderr.
  1107 
  1108 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1109 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1110 
  1111 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1112 way of changing the user's settings is via
  1113 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1114 script.
  1115 
  1116 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1117 cores of the underlying machine, which is a good starting point for
  1118 optimal performance tuning.  The corresponding usedir option -M allows
  1119 "max" as an alias for "0".  WARNING: does not work on certain versions
  1120 of Mac OS (with Poly/ML 5.1).
  1121 
  1122 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1123 adverse effect of Isabelle flooding interactive front-ends (notably
  1124 ProofGeneral / XEmacs).
  1125 
  1126 
  1127 
  1128 New in Isabelle2007 (November 2007)
  1129 -----------------------------------
  1130 
  1131 *** General ***
  1132 
  1133 * More uniform information about legacy features, notably a
  1134 warning/error of "Legacy feature: ...", depending on the state of the
  1135 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1136 legacy features will disappear eventually.
  1137 
  1138 * Theory syntax: the header format ``theory A = B + C:'' has been
  1139 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1140 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1141 
  1142 * Theory syntax: the old non-Isar theory file format has been
  1143 discontinued altogether.  Note that ML proof scripts may still be used
  1144 with Isar theories; migration is usually quite simple with the ML
  1145 function use_legacy_bindings.  INCOMPATIBILITY.
  1146 
  1147 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1148 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1149 quotes.
  1150 
  1151 * Theory loader: be more serious about observing the static theory
  1152 header specifications (including optional directories), but not the
  1153 accidental file locations of previously successful loads.  The strict
  1154 update policy of former update_thy is now already performed by
  1155 use_thy, so the former has been removed; use_thys updates several
  1156 theories simultaneously, just as 'imports' within a theory header
  1157 specification, but without merging the results.  Potential
  1158 INCOMPATIBILITY: may need to refine theory headers and commands
  1159 ROOT.ML which depend on load order.
  1160 
  1161 * Theory loader: optional support for content-based file
  1162 identification, instead of the traditional scheme of full physical
  1163 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1164 (cf. the system manual).  The new scheme allows to work with
  1165 non-finished theories in persistent session images, such that source
  1166 files may be moved later on without requiring reloads.
  1167 
  1168 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1169 file (with the same base name as the theory) are considered a legacy
  1170 feature, which will disappear eventually. Even now, the theory loader
  1171 no longer maintains dependencies on such files.
  1172 
  1173 * Syntax: the scope for resolving ambiguities via type-inference is
  1174 now limited to individual terms, instead of whole simultaneous
  1175 specifications as before. This greatly reduces the complexity of the
  1176 syntax module and improves flexibility by separating parsing and
  1177 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1178 'fixes' etc.) are required in rare situations.
  1179 
  1180 * Syntax: constants introduced by new-style packages ('definition',
  1181 'abbreviation' etc.) are passed through the syntax module in
  1182 ``authentic mode''. This means that associated mixfix annotations
  1183 really stick to such constants, independently of potential name space
  1184 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1185 trees are represented slightly differently, may need to adapt syntax
  1186 translations accordingly. Use CONST marker in 'translations' and
  1187 @{const_syntax} antiquotation in 'parse_translation' etc.
  1188 
  1189 * Legacy goal package: reduced interface to the bare minimum required
  1190 to keep existing proof scripts running.  Most other user-level
  1191 functions are now part of the OldGoals structure, which is *not* open
  1192 by default (consider isatool expandshort before open OldGoals).
  1193 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1194 these tend to cause confusion about the actual goal (!) context being
  1195 used here, which is not necessarily the same as the_context().
  1196 
  1197 * Command 'find_theorems': supports "*" wild-card in "name:"
  1198 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1199 support a specific search form (see ProofGeneral/CHANGES).
  1200 
  1201 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1202 by default, which means that "prems" (and also "fixed variables") are
  1203 suppressed from proof state output.  Note that the ProofGeneral
  1204 settings mechanism allows to change and save options persistently, but
  1205 older versions of Isabelle will fail to start up if a negative prems
  1206 limit is imposed.
  1207 
  1208 * Local theory targets may be specified by non-nested blocks of
  1209 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1210 contain definitions, theorems etc., including any derived mechanism
  1211 that has been implemented on top of these primitives.  This concept
  1212 generalizes the existing ``theorem (in ...)'' towards more versatility
  1213 and scalability.
  1214 
  1215 * Proof General interface: proper undo of final 'end' command;
  1216 discontinued Isabelle/classic mode (ML proof scripts).
  1217 
  1218 
  1219 *** Document preparation ***
  1220 
  1221 * Added antiquotation @{theory name} which prints the given name,
  1222 after checking that it refers to a valid ancestor theory in the
  1223 current context.
  1224 
  1225 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1226 check the given source text as ML type/structure, printing verbatim.
  1227 
  1228 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1229 "c args == rhs" given in the current context.  (Any number of
  1230 arguments may be given on the LHS.)
  1231 
  1232 
  1233 *** Pure ***
  1234 
  1235 * The 'class' package offers a combination of axclass and locale to
  1236 achieve Haskell-like type classes in Isabelle.  Definitions and
  1237 theorems within a class context produce both relative results (with
  1238 implicit parameters according to the locale context), and polymorphic
  1239 constants with qualified polymorphism (according to the class
  1240 context).  Within the body context of a 'class' target, a separate
  1241 syntax layer ("user space type system") takes care of converting
  1242 between global polymorphic consts and internal locale representation.
  1243 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1244 "isatool doc classes" provides a tutorial.
  1245 
  1246 * Generic code generator framework allows to generate executable
  1247 code for ML and Haskell (including Isabelle classes).  A short usage
  1248 sketch:
  1249 
  1250     internal compilation:
  1251         export_code <list of constants (term syntax)> in SML
  1252     writing SML code to a file:
  1253         export_code <list of constants (term syntax)> in SML <filename>
  1254     writing OCaml code to a file:
  1255         export_code <list of constants (term syntax)> in OCaml <filename>
  1256     writing Haskell code to a bunch of files:
  1257         export_code <list of constants (term syntax)> in Haskell <filename>
  1258 
  1259     evaluating closed propositions to True/False using code generation:
  1260         method ``eval''
  1261 
  1262 Reasonable default setup of framework in HOL.
  1263 
  1264 Theorem attributs for selecting and transforming function equations theorems:
  1265 
  1266     [code fun]:        select a theorem as function equation for a specific constant
  1267     [code fun del]:    deselect a theorem as function equation for a specific constant
  1268     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1269     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1270 
  1271 User-defined serializations (target in {SML, OCaml, Haskell}):
  1272 
  1273     code_const <and-list of constants (term syntax)>
  1274       {(target) <and-list of const target syntax>}+
  1275 
  1276     code_type <and-list of type constructors>
  1277       {(target) <and-list of type target syntax>}+
  1278 
  1279     code_instance <and-list of instances>
  1280       {(target)}+
  1281         where instance ::= <type constructor> :: <class>
  1282 
  1283     code_class <and_list of classes>
  1284       {(target) <and-list of class target syntax>}+
  1285         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1286 
  1287 code_instance and code_class only are effective to target Haskell.
  1288 
  1289 For example usage see src/HOL/ex/Codegenerator.thy and
  1290 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1291 generation from Isabelle/HOL theories is available via "isatool doc
  1292 codegen".
  1293 
  1294 * Code generator: consts in 'consts_code' Isar commands are now
  1295 referred to by usual term syntax (including optional type
  1296 annotations).
  1297 
  1298 * Command 'no_translations' removes translation rules from theory
  1299 syntax.
  1300 
  1301 * Overloaded definitions are now actually checked for acyclic
  1302 dependencies.  The overloading scheme is slightly more general than
  1303 that of Haskell98, although Isabelle does not demand an exact
  1304 correspondence to type class and instance declarations.
  1305 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1306 exotic versions of overloading -- at the discretion of the user!
  1307 
  1308 Polymorphic constants are represented via type arguments, i.e. the
  1309 instantiation that matches an instance against the most general
  1310 declaration given in the signature.  For example, with the declaration
  1311 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1312 as c(nat).  Overloading is essentially simultaneous structural
  1313 recursion over such type arguments.  Incomplete specification patterns
  1314 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1315 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1316 Command 'print_theory' outputs the normalized system of recursive
  1317 equations, see section "definitions".
  1318 
  1319 * Configuration options are maintained within the theory or proof
  1320 context (with name and type bool/int/string), providing a very simple
  1321 interface to a poor-man's version of general context data.  Tools may
  1322 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1323 these values using Config.get etc.  Users may change options via an
  1324 associated attribute of the same name.  This form of context
  1325 declaration works particularly well with commands 'declare' or
  1326 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1327 very easy to avoid global references, which would not observe Isar
  1328 toplevel undo/redo and fail to work with multithreading.
  1329 
  1330 Various global ML references of Pure and HOL have been turned into
  1331 configuration options:
  1332 
  1333   Unify.search_bound		unify_search_bound
  1334   Unify.trace_bound		unify_trace_bound
  1335   Unify.trace_simp		unify_trace_simp
  1336   Unify.trace_types		unify_trace_types
  1337   Simplifier.simp_depth_limit	simp_depth_limit
  1338   Blast.depth_limit		blast_depth_limit
  1339   DatatypeProp.dtK		datatype_distinctness_limit
  1340   fast_arith_neq_limit  	fast_arith_neq_limit
  1341   fast_arith_split_limit	fast_arith_split_limit
  1342 
  1343 * Named collections of theorems may be easily installed as context
  1344 data using the functor NamedThmsFun (see also
  1345 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1346 attributes; there is also a toplevel print command.  This facility is
  1347 just a common case of general context data, which is the preferred way
  1348 for anything more complex than just a list of facts in canonical
  1349 order.
  1350 
  1351 * Isar: command 'declaration' augments a local theory by generic
  1352 declaration functions written in ML.  This enables arbitrary content
  1353 being added to the context, depending on a morphism that tells the
  1354 difference of the original declaration context wrt. the application
  1355 context encountered later on.
  1356 
  1357 * Isar: proper interfaces for simplification procedures.  Command
  1358 'simproc_setup' declares named simprocs (with match patterns, and body
  1359 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1360 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1361 
  1362 * Isar: an extra pair of brackets around attribute declarations
  1363 abbreviates a theorem reference involving an internal dummy fact,
  1364 which will be ignored later --- only the effect of the attribute on
  1365 the background context will persist.  This form of in-place
  1366 declarations is particularly useful with commands like 'declare' and
  1367 'using', for example ``have A using [[simproc a]] by simp''.
  1368 
  1369 * Isar: method "assumption" (and implicit closing of subproofs) now
  1370 takes simple non-atomic goal assumptions into account: after applying
  1371 an assumption as a rule the resulting subgoals are solved by atomic
  1372 assumption steps.  This is particularly useful to finish 'obtain'
  1373 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1374 without referring to the original premise "!!x. P x ==> thesis" in the
  1375 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1376 more permissive.
  1377 
  1378 * Isar: implicit use of prems from the Isar proof context is
  1379 considered a legacy feature.  Common applications like ``have A .''
  1380 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1381 referencing facts explicitly here improves readability and
  1382 maintainability of proof texts.
  1383 
  1384 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1385 the obtained context from the course of reasoning!  For example:
  1386 
  1387   assume "EX x y. A x & B y"   -- "any previous fact"
  1388   then guess x and y by clarify
  1389 
  1390 This technique is potentially adventurous, depending on the facts and
  1391 proof tools being involved here.
  1392 
  1393 * Isar: known facts from the proof context may be specified as literal
  1394 propositions, using ASCII back-quote syntax.  This works wherever
  1395 named facts used to be allowed so far, in proof commands, proof
  1396 methods, attributes etc.  Literal facts are retrieved from the context
  1397 according to unification of type and term parameters.  For example,
  1398 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1399 theorems in the current context, then these are valid literal facts:
  1400 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1401 
  1402 There is also a proof method "fact" which does the same composition
  1403 for explicit goal states, e.g. the following proof texts coincide with
  1404 certain special cases of literal facts:
  1405 
  1406   have "A" by fact                 ==  note `A`
  1407   have "A ==> B" by fact           ==  note `A ==> B`
  1408   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1409   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1410 
  1411 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1412 outer syntax.  Thus symbolic identifiers may be used without
  1413 additional white space in declarations like this: ``assume *: A''.
  1414 
  1415 * Isar: 'print_facts' prints all local facts of the current context,
  1416 both named and unnamed ones.
  1417 
  1418 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1419 
  1420   def x == "t" and y == "u"
  1421 
  1422 * Isar: added command 'unfolding', which is structurally similar to
  1423 'using', but affects both the goal state and facts by unfolding given
  1424 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1425 'unfolded' attribute may be replaced by first-class proof text.
  1426 
  1427 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1428 and command 'unfolding' now all support object-level equalities
  1429 (potentially conditional).  The underlying notion of rewrite rule is
  1430 analogous to the 'rule_format' attribute, but *not* that of the
  1431 Simplifier (which is usually more generous).
  1432 
  1433 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1434 premises of a theorem by n. Useful in conjunction with drule.
  1435 
  1436 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1437 method expression within a sandbox consisting of the first N
  1438 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1439 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1440 simplifies all new goals that emerge from applying rule foo to the
  1441 originally first one.
  1442 
  1443 * Isar: schematic goals are no longer restricted to higher-order
  1444 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1445 expected.
  1446 
  1447 * Isar: the conclusion of a long theorem statement is now either
  1448 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1449 (essentially a disjunction of cases with local parameters and
  1450 assumptions).  The latter allows to express general elimination rules
  1451 adequately; in this notation common elimination rules look like this:
  1452 
  1453   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1454     assumes "EX x. P x"
  1455     obtains x where "P x"
  1456 
  1457   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1458     assumes "A & B"
  1459     obtains A and B
  1460 
  1461   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1462     assumes "A | B"
  1463     obtains
  1464       A
  1465     | B
  1466 
  1467 The subsequent classical rules even refer to the formal "thesis"
  1468 explicitly:
  1469 
  1470   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1471     obtains "~ thesis"
  1472 
  1473   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1474     obtains "thesis ==> something"
  1475 
  1476 The actual proof of an 'obtains' statement is analogous to that of the
  1477 Isar proof element 'obtain', only that there may be several cases.
  1478 Optional case names may be specified in parentheses; these will be
  1479 available both in the present proof and as annotations in the
  1480 resulting rule, for later use with the 'cases' method (cf. attribute
  1481 case_names).
  1482 
  1483 * Isar: the assumptions of a long theorem statement are available as
  1484 "assms" fact in the proof context.  This is more appropriate than the
  1485 (historical) "prems", which refers to all assumptions of the current
  1486 context, including those from the target locale, proof body etc.
  1487 
  1488 * Isar: 'print_statement' prints theorems from the current theory or
  1489 proof context in long statement form, according to the syntax of a
  1490 top-level lemma.
  1491 
  1492 * Isar: 'obtain' takes an optional case name for the local context
  1493 introduction rule (default "that").
  1494 
  1495 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1496 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1497 to occur.
  1498 
  1499 * Pure: syntax "CONST name" produces a fully internalized constant
  1500 according to the current context.  This is particularly useful for
  1501 syntax translations that should refer to internal constant
  1502 representations independently of name spaces.
  1503 
  1504 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1505 instead of "FOO ". This allows multiple binder declarations to coexist
  1506 in the same context.  INCOMPATIBILITY.
  1507 
  1508 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1509 primitive that also works in a locale context (both for constants and
  1510 fixed variables). Type declaration and internal syntactic representation
  1511 of given constants retrieved from the context. Likewise, the
  1512 'no_notation' command allows to remove given syntax annotations from the
  1513 current context.
  1514 
  1515 * Isar/locales: new derived specification elements 'axiomatization',
  1516 'definition', 'abbreviation', which support type-inference, admit
  1517 object-level specifications (equality, equivalence).  See also the
  1518 isar-ref manual.  Examples:
  1519 
  1520   axiomatization
  1521     eq  (infix "===" 50) where
  1522     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1523 
  1524   definition "f x y = x + y + 1"
  1525   definition g where "g x = f x x"
  1526 
  1527   abbreviation
  1528     neq  (infix "=!=" 50) where
  1529     "x =!= y == ~ (x === y)"
  1530 
  1531 These specifications may be also used in a locale context.  Then the
  1532 constants being introduced depend on certain fixed parameters, and the
  1533 constant name is qualified by the locale base name.  An internal
  1534 abbreviation takes care for convenient input and output, making the
  1535 parameters implicit and using the original short name.  See also
  1536 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1537 entities from a monomorphic theory.
  1538 
  1539 Presently, abbreviations are only available 'in' a target locale, but
  1540 not inherited by general import expressions.  Also note that
  1541 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1542 'translations' in common applications.  The "no_abbrevs" print mode
  1543 prevents folding of abbreviations in term output.
  1544 
  1545 Concrete syntax is attached to specified constants in internal form,
  1546 independently of name spaces.  The parse tree representation is
  1547 slightly different -- use 'notation' instead of raw 'syntax', and
  1548 'translations' with explicit "CONST" markup to accommodate this.
  1549 
  1550 * Pure/Isar: unified syntax for new-style specification mechanisms
  1551 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1552 full type inference and dummy patterns ("_").  For example:
  1553 
  1554   definition "K x _ = x"
  1555 
  1556   inductive conj for A B
  1557   where "A ==> B ==> conj A B"
  1558 
  1559 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1560 the current context.  Print mode "no_abbrevs" prevents inversion of
  1561 abbreviations on output.
  1562 
  1563 * Isar/locales: improved parameter handling: use of locales "var" and
  1564 "struct" no longer necessary; - parameter renamings are no longer
  1565 required to be injective.  For example, this allows to define
  1566 endomorphisms as locale endom = homom mult mult h.
  1567 
  1568 * Isar/locales: changed the way locales with predicates are defined.
  1569 Instead of accumulating the specification, the imported expression is
  1570 now an interpretation.  INCOMPATIBILITY: different normal form of
  1571 locale expressions.  In particular, in interpretations of locales with
  1572 predicates, goals repesenting already interpreted fragments are not
  1573 removed automatically.  Use methods `intro_locales' and
  1574 `unfold_locales'; see below.
  1575 
  1576 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1577 provide backward reasoning on locales predicates.  The methods are
  1578 aware of interpretations and discharge corresponding goals.
  1579 `intro_locales' is less aggressive then `unfold_locales' and does not
  1580 unfold predicates to assumptions.
  1581 
  1582 * Isar/locales: the order in which locale fragments are accumulated
  1583 has changed.  This enables to override declarations from fragments due
  1584 to interpretations -- for example, unwanted simp rules.
  1585 
  1586 * Isar/locales: interpretation in theories and proof contexts has been
  1587 extended.  One may now specify (and prove) equations, which are
  1588 unfolded in interpreted theorems.  This is useful for replacing
  1589 defined concepts (constants depending on locale parameters) by
  1590 concepts already existing in the target context.  Example:
  1591 
  1592   interpretation partial_order ["op <= :: [int, int] => bool"]
  1593     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1594 
  1595 Typically, the constant `partial_order.less' is created by a
  1596 definition specification element in the context of locale
  1597 partial_order.
  1598 
  1599 * Method "induct": improved internal context management to support
  1600 local fixes and defines on-the-fly. Thus explicit meta-level
  1601 connectives !!  and ==> are rarely required anymore in inductive goals
  1602 (using object-logic connectives for this purpose has been long
  1603 obsolete anyway). Common proof patterns are explained in
  1604 src/HOL/Induct/Common_Patterns.thy, see also
  1605 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1606 examples.
  1607 
  1608 * Method "induct": improved handling of simultaneous goals. Instead of
  1609 introducing object-level conjunction, the statement is now split into
  1610 several conclusions, while the corresponding symbolic cases are nested
  1611 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1612 see src/HOL/Induct/Common_Patterns.thy, for example.
  1613 
  1614 * Method "induct": mutual induction rules are now specified as a list
  1615 of rule sharing the same induction cases. HOL packages usually provide
  1616 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1617 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1618 mutual induction rules differently, i.e. like this:
  1619 
  1620   (induct rule: foo_bar.inducts)
  1621   (induct set: foo bar)
  1622   (induct pred: foo bar)
  1623   (induct type: foo bar)
  1624 
  1625 The ML function ProjectRule.projections turns old-style rules into the
  1626 new format.
  1627 
  1628 * Method "coinduct": dual of induction, see
  1629 src/HOL/Library/Coinductive_List.thy for various examples.
  1630 
  1631 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1632 considered a legacy feature.
  1633 
  1634 * Attribute "symmetric" produces result with standardized schematic
  1635 variables (index 0).  Potential INCOMPATIBILITY.
  1636 
  1637 * Simplifier: by default the simplifier trace only shows top level
  1638 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1639 default. Thus there is less danger of being flooded by the trace. The
  1640 trace indicates where parts have been suppressed.
  1641   
  1642 * Provers/classical: removed obsolete classical version of elim_format
  1643 attribute; classical elim/dest rules are now treated uniformly when
  1644 manipulating the claset.
  1645 
  1646 * Provers/classical: stricter checks to ensure that supplied intro,
  1647 dest and elim rules are well-formed; dest and elim rules must have at
  1648 least one premise.
  1649 
  1650 * Provers/classical: attributes dest/elim/intro take an optional
  1651 weight argument for the rule (just as the Pure versions).  Weights are
  1652 ignored by automated tools, but determine the search order of single
  1653 rule steps.
  1654 
  1655 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1656 where the body does not mention the bound variable.  Note that dummy
  1657 patterns implicitly depend on their context of bounds, which makes
  1658 "{_. _}" match any set comprehension as expected.  Potential
  1659 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1660 constant "_idtdummy" in the binding position.
  1661 
  1662 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1663 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1664 for example "A -> B" => "Pi A (%_. B)".
  1665 
  1666 * Pure: 'class_deps' command visualizes the subclass relation, using
  1667 the graph browser tool.
  1668 
  1669 * Pure: 'print_theory' now suppresses certain internal declarations by
  1670 default; use '!' option for full details.
  1671 
  1672 
  1673 *** HOL ***
  1674 
  1675 * Method "metis" proves goals by applying the Metis general-purpose
  1676 resolution prover (see also http://gilith.com/software/metis/).
  1677 Examples are in the directory MetisExamples.  WARNING: the
  1678 Isabelle/HOL-Metis integration does not yet work properly with
  1679 multi-threading.
  1680   
  1681 * Command 'sledgehammer' invokes external automatic theorem provers as
  1682 background processes.  It generates calls to the "metis" method if
  1683 successful. These can be pasted into the proof.  Users do not have to
  1684 wait for the automatic provers to return.  WARNING: does not really
  1685 work with multi-threading.
  1686 
  1687 * New "auto_quickcheck" feature tests outermost goal statements for
  1688 potential counter-examples.  Controlled by ML references
  1689 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1690 5000 milliseconds).  Fails silently if statements is outside of
  1691 executable fragment, or any other codgenerator problem occurs.
  1692 
  1693 * New constant "undefined" with axiom "undefined x = undefined".
  1694 
  1695 * Added class "HOL.eq", allowing for code generation with polymorphic
  1696 equality.
  1697 
  1698 * Some renaming of class constants due to canonical name prefixing in
  1699 the new 'class' package:
  1700 
  1701     HOL.abs ~> HOL.abs_class.abs
  1702     HOL.divide ~> HOL.divide_class.divide
  1703     0 ~> HOL.zero_class.zero
  1704     1 ~> HOL.one_class.one
  1705     op + ~> HOL.plus_class.plus
  1706     op - ~> HOL.minus_class.minus
  1707     uminus ~> HOL.minus_class.uminus
  1708     op * ~> HOL.times_class.times
  1709     op < ~> HOL.ord_class.less
  1710     op <= > HOL.ord_class.less_eq
  1711     Nat.power ~> Power.power_class.power
  1712     Nat.size ~> Nat.size_class.size
  1713     Numeral.number_of ~> Numeral.number_class.number_of
  1714     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1715     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1716     Orderings.min ~> Orderings.ord_class.min
  1717     Orderings.max ~> Orderings.ord_class.max
  1718     Divides.op div ~> Divides.div_class.div
  1719     Divides.op mod ~> Divides.div_class.mod
  1720     Divides.op dvd ~> Divides.div_class.dvd
  1721 
  1722 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1723 
  1724 a) User-defined constants using any of the names "plus", "minus",
  1725 "times", "less" or "less_eq". The standard syntax translations for
  1726 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1727 names.
  1728 
  1729 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1730 INCOMPATIBILITY: use more specific names.
  1731 
  1732 c) Permutative equations (e.g. "a + b = b + a")
  1733 Since the change of names also changes the order of terms, permutative
  1734 rewrite rules may get applied in a different order. Experience shows
  1735 that this is rarely the case (only two adaptions in the whole Isabelle
  1736 distribution).  INCOMPATIBILITY: rewrite proofs
  1737 
  1738 d) ML code directly refering to constant names
  1739 This in general only affects hand-written proof tactics, simprocs and
  1740 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1741 Consider using @{const_name} antiquotation.
  1742 
  1743 * New class "default" with associated constant "default".
  1744 
  1745 * Function "sgn" is now overloaded and available on int, real, complex
  1746 (and other numeric types), using class "sgn".  Two possible defs of
  1747 sgn are given as equational assumptions in the classes sgn_if and
  1748 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1749 INCOMPATIBILITY.
  1750 
  1751 * Locale "partial_order" now unified with class "order" (cf. theory
  1752 Orderings), added parameter "less".  INCOMPATIBILITY.
  1753 
  1754 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1755 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1756 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1757 
  1758 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1759 changed order of proof goals in instance proofs.
  1760 
  1761 * The transitivity reasoner for partial and linear orders is set up
  1762 for classes "order" and "linorder".  Instances of the reasoner are available
  1763 in all contexts importing or interpreting the corresponding locales.
  1764 Method "order" invokes the reasoner separately; the reasoner
  1765 is also integrated with the Simplifier as a solver.  Diagnostic
  1766 command 'print_orders' shows the available instances of the reasoner
  1767 in the current context.
  1768 
  1769 * Localized monotonicity predicate in theory "Orderings"; integrated
  1770 lemmas max_of_mono and min_of_mono with this predicate.
  1771 INCOMPATIBILITY.
  1772 
  1773 * Formulation of theorem "dense" changed slightly due to integration
  1774 with new class dense_linear_order.
  1775 
  1776 * Uniform lattice theory development in HOL.
  1777 
  1778     constants "meet" and "join" now named "inf" and "sup"
  1779     constant "Meet" now named "Inf"
  1780 
  1781     classes "meet_semilorder" and "join_semilorder" now named
  1782       "lower_semilattice" and "upper_semilattice"
  1783     class "lorder" now named "lattice"
  1784     class "comp_lat" now named "complete_lattice"
  1785 
  1786     Instantiation of lattice classes allows explicit definitions
  1787     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1788 
  1789   INCOMPATIBILITY.  Theorem renames:
  1790 
  1791     meet_left_le            ~> inf_le1
  1792     meet_right_le           ~> inf_le2
  1793     join_left_le            ~> sup_ge1
  1794     join_right_le           ~> sup_ge2
  1795     meet_join_le            ~> inf_sup_ord
  1796     le_meetI                ~> le_infI
  1797     join_leI                ~> le_supI
  1798     le_meet                 ~> le_inf_iff
  1799     le_join                 ~> ge_sup_conv
  1800     meet_idempotent         ~> inf_idem
  1801     join_idempotent         ~> sup_idem
  1802     meet_comm               ~> inf_commute
  1803     join_comm               ~> sup_commute
  1804     meet_leI1               ~> le_infI1
  1805     meet_leI2               ~> le_infI2
  1806     le_joinI1               ~> le_supI1
  1807     le_joinI2               ~> le_supI2
  1808     meet_assoc              ~> inf_assoc
  1809     join_assoc              ~> sup_assoc
  1810     meet_left_comm          ~> inf_left_commute
  1811     meet_left_idempotent    ~> inf_left_idem
  1812     join_left_comm          ~> sup_left_commute
  1813     join_left_idempotent    ~> sup_left_idem
  1814     meet_aci                ~> inf_aci
  1815     join_aci                ~> sup_aci
  1816     le_def_meet             ~> le_iff_inf
  1817     le_def_join             ~> le_iff_sup
  1818     join_absorp2            ~> sup_absorb2
  1819     join_absorp1            ~> sup_absorb1
  1820     meet_absorp1            ~> inf_absorb1
  1821     meet_absorp2            ~> inf_absorb2
  1822     meet_join_absorp        ~> inf_sup_absorb
  1823     join_meet_absorp        ~> sup_inf_absorb
  1824     distrib_join_le         ~> distrib_sup_le
  1825     distrib_meet_le         ~> distrib_inf_le
  1826 
  1827     add_meet_distrib_left   ~> add_inf_distrib_left
  1828     add_join_distrib_left   ~> add_sup_distrib_left
  1829     is_join_neg_meet        ~> is_join_neg_inf
  1830     is_meet_neg_join        ~> is_meet_neg_sup
  1831     add_meet_distrib_right  ~> add_inf_distrib_right
  1832     add_join_distrib_right  ~> add_sup_distrib_right
  1833     add_meet_join_distribs  ~> add_sup_inf_distribs
  1834     join_eq_neg_meet        ~> sup_eq_neg_inf
  1835     meet_eq_neg_join        ~> inf_eq_neg_sup
  1836     add_eq_meet_join        ~> add_eq_inf_sup
  1837     meet_0_imp_0            ~> inf_0_imp_0
  1838     join_0_imp_0            ~> sup_0_imp_0
  1839     meet_0_eq_0             ~> inf_0_eq_0
  1840     join_0_eq_0             ~> sup_0_eq_0
  1841     neg_meet_eq_join        ~> neg_inf_eq_sup
  1842     neg_join_eq_meet        ~> neg_sup_eq_inf
  1843     join_eq_if              ~> sup_eq_if
  1844 
  1845     mono_meet               ~> mono_inf
  1846     mono_join               ~> mono_sup
  1847     meet_bool_eq            ~> inf_bool_eq
  1848     join_bool_eq            ~> sup_bool_eq
  1849     meet_fun_eq             ~> inf_fun_eq
  1850     join_fun_eq             ~> sup_fun_eq
  1851     meet_set_eq             ~> inf_set_eq
  1852     join_set_eq             ~> sup_set_eq
  1853     meet1_iff               ~> inf1_iff
  1854     meet2_iff               ~> inf2_iff
  1855     meet1I                  ~> inf1I
  1856     meet2I                  ~> inf2I
  1857     meet1D1                 ~> inf1D1
  1858     meet2D1                 ~> inf2D1
  1859     meet1D2                 ~> inf1D2
  1860     meet2D2                 ~> inf2D2
  1861     meet1E                  ~> inf1E
  1862     meet2E                  ~> inf2E
  1863     join1_iff               ~> sup1_iff
  1864     join2_iff               ~> sup2_iff
  1865     join1I1                 ~> sup1I1
  1866     join2I1                 ~> sup2I1
  1867     join1I1                 ~> sup1I1
  1868     join2I2                 ~> sup1I2
  1869     join1CI                 ~> sup1CI
  1870     join2CI                 ~> sup2CI
  1871     join1E                  ~> sup1E
  1872     join2E                  ~> sup2E
  1873 
  1874     is_meet_Meet            ~> is_meet_Inf
  1875     Meet_bool_def           ~> Inf_bool_def
  1876     Meet_fun_def            ~> Inf_fun_def
  1877     Meet_greatest           ~> Inf_greatest
  1878     Meet_lower              ~> Inf_lower
  1879     Meet_set_def            ~> Inf_set_def
  1880 
  1881     Sup_def                 ~> Sup_Inf
  1882     Sup_bool_eq             ~> Sup_bool_def
  1883     Sup_fun_eq              ~> Sup_fun_def
  1884     Sup_set_eq              ~> Sup_set_def
  1885 
  1886     listsp_meetI            ~> listsp_infI
  1887     listsp_meet_eq          ~> listsp_inf_eq
  1888 
  1889     meet_min                ~> inf_min
  1890     join_max                ~> sup_max
  1891 
  1892 * Added syntactic class "size"; overloaded constant "size" now has
  1893 type "'a::size ==> bool"
  1894 
  1895 * Internal reorganisation of `size' of datatypes: size theorems
  1896 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1897 simplification rules by default!); theorems "prod.size" now named
  1898 "*.size".
  1899 
  1900 * Class "div" now inherits from class "times" rather than "type".
  1901 INCOMPATIBILITY.
  1902 
  1903 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1904 Linorder etc.  have disappeared; operations defined in terms of
  1905 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1906 
  1907 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1908 
  1909 * HOL-Word: New extensive library and type for generic, fixed size
  1910 machine words, with arithemtic, bit-wise, shifting and rotating
  1911 operations, reflection into int, nat, and bool lists, automation for
  1912 linear arithmetic (by automatic reflection into nat or int), including
  1913 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1914 arithmetic type classes, supporting automatic simplification of
  1915 numerals on all operations.
  1916 
  1917 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1918 
  1919 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1920 
  1921 * Code generator library theories:
  1922   - Code_Integer represents HOL integers by big integer literals in target
  1923     languages.
  1924   - Code_Char represents HOL characters by character literals in target
  1925     languages.
  1926   - Code_Char_chr like Code_Char, but also offers treatment of character
  1927     codes; includes Code_Integer.
  1928   - Executable_Set allows to generate code for finite sets using lists.
  1929   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1930     denominator).
  1931   - Executable_Real implements a subset of real numbers, namly those
  1932     representable by rational numbers.
  1933   - Efficient_Nat implements natural numbers by integers, which in general will
  1934     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1935     includes Code_Integer.
  1936   - Code_Index provides an additional datatype index which is mapped to
  1937     target-language built-in integers.
  1938   - Code_Message provides an additional datatype message_string which is isomorphic to
  1939     strings; messages are mapped to target-language strings.
  1940 
  1941 * New package for inductive predicates
  1942 
  1943   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1944 
  1945     inductive
  1946       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1947       for z_1 :: U_1 and ... and z_n :: U_m
  1948     where
  1949       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1950     | ...
  1951 
  1952   with full support for type-inference, rather than
  1953 
  1954     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1955 
  1956     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1957     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1958 
  1959     inductive "s z_1 ... z_m"
  1960     intros
  1961       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1962       ...
  1963 
  1964   For backward compatibility, there is a wrapper allowing inductive
  1965   sets to be defined with the new package via
  1966 
  1967     inductive_set
  1968       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1969       for z_1 :: U_1 and ... and z_n :: U_m
  1970     where
  1971       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1972     | ...
  1973 
  1974   or
  1975 
  1976     inductive_set
  1977       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1978       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1979       for z_1 :: U_1 and ... and z_n :: U_m
  1980     where
  1981       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1982     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1983     | ...
  1984 
  1985   if the additional syntax "p ..." is required.
  1986 
  1987   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1988   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1989 
  1990   INCOMPATIBILITIES:
  1991 
  1992   - Since declaration and definition of inductive sets or predicates
  1993     is no longer separated, abbreviations involving the newly
  1994     introduced sets or predicates must be specified together with the
  1995     introduction rules after the 'where' keyword (see above), rather
  1996     than before the actual inductive definition.
  1997 
  1998   - The variables in induction and elimination rules are now
  1999     quantified in the order of their occurrence in the introduction
  2000     rules, rather than in alphabetical order. Since this may break
  2001     some proofs, these proofs either have to be repaired, e.g. by
  2002     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2003     statements of the form
  2004 
  2005       case (rule_i a_i_1 ... a_i_{k_i})
  2006 
  2007     or the old order of quantification has to be restored by explicitly adding
  2008     meta-level quantifiers in the introduction rules, i.e.
  2009 
  2010       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2011 
  2012   - The format of the elimination rules is now
  2013 
  2014       p z_1 ... z_m x_1 ... x_n ==>
  2015         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2016         ==> ... ==> P
  2017 
  2018     for predicates and
  2019 
  2020       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2021         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2022         ==> ... ==> P
  2023 
  2024     for sets rather than
  2025 
  2026       x : s z_1 ... z_m ==>
  2027         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2028         ==> ... ==> P
  2029 
  2030     This may require terms in goals to be expanded to n-tuples
  2031     (e.g. using case_tac or simplification with the split_paired_all
  2032     rule) before the above elimination rule is applicable.
  2033 
  2034   - The elimination or case analysis rules for (mutually) inductive
  2035     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2036     list of rules "p_1_..._p_k.elims" is no longer available.
  2037 
  2038 * New package "function"/"fun" for general recursive functions,
  2039 supporting mutual and nested recursion, definitions in local contexts,
  2040 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2041 for small examples, and the separate tutorial on the function
  2042 package. The old recdef "package" is still available as before, but
  2043 users are encouraged to use the new package.
  2044 
  2045 * Method "lexicographic_order" automatically synthesizes termination
  2046 relations as lexicographic combinations of size measures. 
  2047 
  2048 * Case-expressions allow arbitrary constructor-patterns (including
  2049 "_") and take their order into account, like in functional
  2050 programming.  Internally, this is translated into nested
  2051 case-expressions; missing cases are added and mapped to the predefined
  2052 constant "undefined". In complicated cases printing may no longer show
  2053 the original input but the internal form. Lambda-abstractions allow
  2054 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2055 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2056 variable.
  2057 
  2058 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2059 is an abbreviation for "of_nat :: nat => int". The simplification
  2060 rules for "of_nat" have been changed to work like "int" did
  2061 previously.  Potential INCOMPATIBILITY:
  2062   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2063   - of_nat_diff and of_nat_mult are no longer default simp rules
  2064 
  2065 * Method "algebra" solves polynomial equations over (semi)rings using
  2066 Groebner bases. The (semi)ring structure is defined by locales and the
  2067 tool setup depends on that generic context. Installing the method for
  2068 a specific type involves instantiating the locale and possibly adding
  2069 declarations for computation on the coefficients.  The method is
  2070 already instantiated for natural numbers and for the axiomatic class
  2071 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2072 CALCULEMUS 2007 for the general principles underlying this
  2073 architecture of context-aware proof-tools.
  2074 
  2075 * Method "ferrack" implements quantifier elimination over
  2076 special-purpose dense linear orders using locales (analogous to
  2077 "algebra"). The method is already installed for class
  2078 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2079 rat, etc.
  2080 
  2081 * Former constant "List.op @" now named "List.append".  Use ML
  2082 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2083 circumvent possible incompatibilities when working on ML level.
  2084 
  2085 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2086 
  2087 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2088 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2089 
  2090 * New syntax for Haskell-like list comprehension (input only), eg.
  2091 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2092 
  2093 * The special syntax for function "filter" has changed from [x :
  2094 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2095 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2096 
  2097 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2098 defined on nat only, as an abbreviation for [a..<Suc b]
  2099 INCOMPATIBILITY.
  2100 
  2101 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2102 
  2103 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2104 
  2105 * New lemma collection field_simps (an extension of ring_simps) for
  2106 manipulating (in)equations involving division. Multiplies with all
  2107 denominators that can be proved to be non-zero (in equations) or
  2108 positive/negative (in inequations).
  2109 
  2110 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2111 have been improved and renamed to ring_simps, group_simps and
  2112 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2113 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2114 
  2115 * Theory Library/Commutative_Ring: switched from recdef to function
  2116 package; constants add, mul, pow now curried.  Infix syntax for
  2117 algebraic operations.
  2118 
  2119 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2120 INCOMPATIBILITY.
  2121 
  2122 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2123 INCOMPATIBILITY.
  2124 
  2125 * HOL/records: generalised field-update to take a function on the
  2126 field rather than the new value: r(|A := x|) is translated to A_update
  2127 (K x) r The K-combinator that is internally used is called K_record.
  2128 INCOMPATIBILITY: Usage of the plain update functions has to be
  2129 adapted.
  2130  
  2131 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2132 * x = 0, which are required for a semiring.  Richer structures do not
  2133 inherit from semiring_0 anymore, because this property is a theorem
  2134 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2135 there is more to prove, but this is mostly trivial.
  2136 
  2137 * Class "recpower" is generalized to arbitrary monoids, not just
  2138 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2139 commutativity or semiring properties additionally.
  2140 
  2141 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2142 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2143 better use 'abbreviation'.
  2144 
  2145 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2146 
  2147 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2148 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2149 significant changes for setting up numeral syntax for types:
  2150   - New constants Numeral.pred and Numeral.succ instead
  2151       of former Numeral.bin_pred and Numeral.bin_succ.
  2152   - Use integer operations instead of bin_add, bin_mult and so on.
  2153   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2154   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2155 
  2156 See src/HOL/Integ/IntArith.thy for an example setup.
  2157 
  2158 * Command 'normal_form' computes the normal form of a term that may
  2159 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2160 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2161 heavy-duty computations because the functions are compiled to ML
  2162 first.  Correspondingly, a method "normalization" is provided.  See
  2163 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2164 
  2165 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2166 25 like -->); output depends on the "iff" print_mode, the default is
  2167 "A = B" (with priority 50).
  2168 
  2169 * Relations less (<) and less_eq (<=) are also available on type bool.
  2170 Modified syntax to disallow nesting without explicit parentheses,
  2171 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2172 INCOMPATIBILITY.
  2173 
  2174 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2175 
  2176 * Relation composition operator "op O" now has precedence 75 and binds
  2177 stronger than union and intersection. INCOMPATIBILITY.
  2178 
  2179 * The old set interval syntax "{m..n(}" (and relatives) has been
  2180 removed.  Use "{m..<n}" (and relatives) instead.
  2181 
  2182 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2183 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2184 ``declare [[simproc del: neq]]''.
  2185 
  2186 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2187 True/False.
  2188 
  2189 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2190 
  2191 * Theorem setsum_mult renamed to setsum_right_distrib.
  2192 
  2193 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2194 ``rule'' method.
  2195 
  2196 * Reimplemented methods "sat" and "satx", with several improvements:
  2197 goals no longer need to be stated as "<prems> ==> False", equivalences
  2198 (i.e. "=" on type bool) are handled, variable names of the form
  2199 "lit_<n>" are no longer reserved, significant speedup.
  2200 
  2201 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2202 zChaff is still supported as well.
  2203 
  2204 * 'inductive' and 'datatype': provide projections of mutual rules,
  2205 bundled as foo_bar.inducts;
  2206 
  2207 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2208 Library.
  2209 
  2210 * Library: moved theory Accessible_Part to main HOL.
  2211 
  2212 * Library: added theory Coinductive_List of potentially infinite lists
  2213 as greatest fixed-point.
  2214 
  2215 * Library: added theory AssocList which implements (finite) maps as
  2216 association lists.
  2217 
  2218 * Method "evaluation" solves goals (i.e. a boolean expression)
  2219 efficiently by compiling it to ML.  The goal is "proved" (via an
  2220 oracle) if it evaluates to True.
  2221 
  2222 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2223 also when invoked by the simplifier.  This results in the Simplifier
  2224 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2225 Configuration option fast_arith_split_limit=0 recovers the old
  2226 behavior.
  2227 
  2228 * Support for hex (0x20) and binary (0b1001) numerals.
  2229 
  2230 * New method: reify eqs (t), where eqs are equations for an
  2231 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2232 parameter, computes a term s::'b and a list xs::'a list and proves the
  2233 theorem I xs s = t. This is also known as reification or quoting. The
  2234 resulting theorem is applied to the subgoal to substitute t with I xs
  2235 s.  If t is omitted, the subgoal itself is reified.
  2236 
  2237 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2238 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2239 where f is supposed to be a computable function (in the sense of code
  2240 generattion). The method uses reify to compute s and xs as above then
  2241 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2242 r and finally gets the theorem t = r, which is again applied to the
  2243 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2244 
  2245 * Reflection: Automatic reification now handels binding, an example is
  2246 available in src/HOL/ex/ReflectionEx.thy
  2247 
  2248 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2249 command 'statespace' that is similar to 'record', but introduces an
  2250 abstract specification based on the locale infrastructure instead of
  2251 HOL types.  This leads to extra flexibility in composing state spaces,
  2252 in particular multiple inheritance and renaming of components.
  2253 
  2254 
  2255 *** HOL-Complex ***
  2256 
  2257 * Hyperreal: Functions root and sqrt are now defined on negative real
  2258 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2259 Nonnegativity side conditions have been removed from many lemmas, so
  2260 that more subgoals may now be solved by simplification; potential
  2261 INCOMPATIBILITY.
  2262 
  2263 * Real: new type classes formalize real normed vector spaces and
  2264 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2265 and norm :: 'a => real.
  2266 
  2267 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2268 reals into other types. The overloaded constant Reals :: 'a set is now
  2269 defined as range of_real; potential INCOMPATIBILITY.
  2270 
  2271 * Real: proper support for ML code generation, including 'quickcheck'.
  2272 Reals are implemented as arbitrary precision rationals.
  2273 
  2274 * Hyperreal: Several constants that previously worked only for the
  2275 reals have been generalized, so they now work over arbitrary vector
  2276 spaces. Type annotations may need to be added in some cases; potential
  2277 INCOMPATIBILITY.
  2278 
  2279   Infinitesimal  :: ('a::real_normed_vector) star set
  2280   HFinite        :: ('a::real_normed_vector) star set
  2281   HInfinite      :: ('a::real_normed_vector) star set
  2282   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2283   monad          :: ('a::real_normed_vector) star => 'a star set
  2284   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2285   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2286   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2287   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2288   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2289   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2290   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2291   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2292   sgn            :: 'a::real_normed_vector => 'a
  2293   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2294 
  2295 * Complex: Some complex-specific constants are now abbreviations for
  2296 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2297 hnorm.  Other constants have been entirely removed in favor of the
  2298 polymorphic versions (INCOMPATIBILITY):
  2299 
  2300   approx        <-- capprox
  2301   HFinite       <-- CFinite
  2302   HInfinite     <-- CInfinite
  2303   Infinitesimal <-- CInfinitesimal
  2304   monad         <-- cmonad
  2305   galaxy        <-- cgalaxy
  2306   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2307   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2308   (ns)deriv     <-- (ns)cderiv
  2309 
  2310 
  2311 *** HOL-Algebra ***
  2312 
  2313 * Formalisation of ideals and the quotient construction over rings.
  2314 
  2315 * Order and lattice theory no longer based on records.
  2316 INCOMPATIBILITY.
  2317 
  2318 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2319 greatest_closed.  INCOMPATIBILITY.
  2320 
  2321 * Method algebra is now set up via an attribute.  For examples see
  2322 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2323 of algebraic structures.
  2324 
  2325 * Renamed theory CRing to Ring.
  2326 
  2327 
  2328 *** HOL-Nominal ***
  2329 
  2330 * Substantial, yet incomplete support for nominal datatypes (binding
  2331 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2332 src/HOL/Nominal/Examples.  Prospective users should consult
  2333 http://isabelle.in.tum.de/nominal/
  2334 
  2335 
  2336 *** ML ***
  2337 
  2338 * ML basics: just one true type int, which coincides with IntInf.int
  2339 (even on SML/NJ).
  2340 
  2341 * ML within Isar: antiquotations allow to embed statically-checked
  2342 formal entities in the source, referring to the context available at
  2343 compile-time.  For example:
  2344 
  2345 ML {* @{sort "{zero,one}"} *}
  2346 ML {* @{typ "'a => 'b"} *}
  2347 ML {* @{term "%x. x"} *}
  2348 ML {* @{prop "x == y"} *}
  2349 ML {* @{ctyp "'a => 'b"} *}
  2350 ML {* @{cterm "%x. x"} *}
  2351 ML {* @{cprop "x == y"} *}
  2352 ML {* @{thm asm_rl} *}
  2353 ML {* @{thms asm_rl} *}
  2354 ML {* @{type_name c} *}
  2355 ML {* @{type_syntax c} *}
  2356 ML {* @{const_name c} *}
  2357 ML {* @{const_syntax c} *}
  2358 ML {* @{context} *}
  2359 ML {* @{theory} *}
  2360 ML {* @{theory Pure} *}
  2361 ML {* @{theory_ref} *}
  2362 ML {* @{theory_ref Pure} *}
  2363 ML {* @{simpset} *}
  2364 ML {* @{claset} *}
  2365 ML {* @{clasimpset} *}
  2366 
  2367 The same works for sources being ``used'' within an Isar context.
  2368 
  2369 * ML in Isar: improved error reporting; extra verbosity with
  2370 ML_Context.trace enabled.
  2371 
  2372 * Pure/General/table.ML: the join operations now works via exceptions
  2373 DUP/SAME instead of type option. This is simpler in simple cases, and
  2374 admits slightly more efficient complex applications.
  2375 
  2376 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2377 use Context.generic instead of just theory.
  2378 
  2379 * Pure: datatype Context.generic joins theory/Proof.context and
  2380 provides some facilities for code that works in either kind of
  2381 context, notably GenericDataFun for uniform theory and proof data.
  2382 
  2383 * Pure: simplified internal attribute type, which is now always
  2384 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2385 local (Proof.context) attributes have been discontinued, while
  2386 minimizing code duplication. Thm.rule_attribute and
  2387 Thm.declaration_attribute build canonical attributes; see also structure
  2388 Context for further operations on Context.generic, notably
  2389 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2390 declarations and definitions.
  2391 
  2392 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2393 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2394 init only required for impure data. INCOMPATIBILITY: empty really need
  2395 to be empty (no dependencies on theory content!)
  2396 
  2397 * Pure/kernel: consts certification ignores sort constraints given in
  2398 signature declarations. (This information is not relevant to the
  2399 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2400 potential INCOMPATIBILITY.
  2401 
  2402 * Pure: axiomatic type classes are now purely definitional, with
  2403 explicit proofs of class axioms and super class relations performed
  2404 internally. See Pure/axclass.ML for the main internal interfaces --
  2405 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2406 AxClass.axiomatize_class/classrel/arity supersede
  2407 Sign.add_classes/classrel/arities.
  2408 
  2409 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2410 global/local versions on theory vs. Proof.context have been
  2411 discontinued; Attrib.syntax and Method.syntax have been adapted
  2412 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2413 attributes, methods, etc.
  2414 
  2415 * Pure: several functions of signature "... -> theory -> theory * ..."
  2416 have been reoriented to "... -> theory -> ... * theory" in order to
  2417 allow natural usage in combination with the ||>, ||>>, |-> and
  2418 fold_map combinators.
  2419 
  2420 * Pure: official theorem names (closed derivations) and additional
  2421 comments (tags) are now strictly separate.  Name hints -- which are
  2422 maintained as tags -- may be attached any time without affecting the
  2423 derivation.
  2424 
  2425 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2426 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2427 achieve the old behaviour.
  2428 
  2429 * Pure: the "Goal" constant is now called "prop", supporting a
  2430 slightly more general idea of ``protecting'' meta-level rule
  2431 statements.
  2432 
  2433 * Pure: Logic.(un)varify only works in a global context, which is now
  2434 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2435 Logic.legacy_(un)varify as temporary workaround.
  2436 
  2437 * Pure: structure Name provides scalable operations for generating
  2438 internal variable names, notably Name.variants etc.  This replaces
  2439 some popular functions from term.ML:
  2440 
  2441   Term.variant		->  Name.variant
  2442   Term.variantlist	->  Name.variant_list
  2443   Term.invent_names	->  Name.invent_list
  2444 
  2445 Note that low-level renaming rarely occurs in new code -- operations
  2446 from structure Variable are used instead (see below).
  2447 
  2448 * Pure: structure Variable provides fundamental operations for proper
  2449 treatment of fixed/schematic variables in a context.  For example,
  2450 Variable.import introduces fixes for schematics of given facts and
  2451 Variable.export reverses the effect (up to renaming) -- this replaces
  2452 various freeze_thaw operations.
  2453 
  2454 * Pure: structure Goal provides simple interfaces for
  2455 init/conclude/finish and tactical prove operations (replacing former
  2456 Tactic.prove).  Goal.prove is the canonical way to prove results
  2457 within a given context; Goal.prove_global is a degraded version for
  2458 theory level goals, including a global Drule.standard.  Note that
  2459 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2460 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2461 in a locale context).
  2462 
  2463 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2464 and type checking (Syntax.check_term etc.), with common combinations
  2465 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2466 which are considered legacy and await removal.
  2467 
  2468 * Pure/Syntax: generic interfaces for type unchecking
  2469 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2470 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2471 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2472 available for convenience, but refer to the very same operations using
  2473 a mere theory instead of a full context.
  2474 
  2475 * Isar: simplified treatment of user-level errors, using exception
  2476 ERROR of string uniformly.  Function error now merely raises ERROR,
  2477 without any side effect on output channels.  The Isar toplevel takes
  2478 care of proper display of ERROR exceptions.  ML code may use plain
  2479 handle/can/try; cat_error may be used to concatenate errors like this:
  2480 
  2481   ... handle ERROR msg => cat_error msg "..."
  2482 
  2483 Toplevel ML code (run directly or through the Isar toplevel) may be
  2484 embedded into the Isar toplevel with exception display/debug like
  2485 this:
  2486 
  2487   Isar.toplevel (fn () => ...)
  2488 
  2489 INCOMPATIBILITY, removed special transform_error facilities, removed
  2490 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2491 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2492 -- use plain ERROR instead.
  2493 
  2494 * Isar: theory setup now has type (theory -> theory), instead of a
  2495 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2496 
  2497 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2498 ProofContext.debug/verbose flags.
  2499 
  2500 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2501 theory before entering a proof state.  Transactions now always see a
  2502 quasi-functional intermediate checkpoint, both in interactive and
  2503 batch mode.
  2504 
  2505 * Isar: simplified interfaces for outer syntax.  Renamed
  2506 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2507 OuterSyntax.add_parsers -- this functionality is now included in
  2508 OuterSyntax.command etc.  INCOMPATIBILITY.
  2509 
  2510 * Simplifier: the simpset of a running simplification process now
  2511 contains a proof context (cf. Simplifier.the_context), which is the
  2512 very context that the initial simpset has been retrieved from (by
  2513 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2514 (solver, looper etc.) may depend on arbitrary proof data.
  2515 
  2516 * Simplifier.inherit_context inherits the proof context (plus the
  2517 local bounds) of the current simplification process; any simproc
  2518 etc. that calls the Simplifier recursively should do this!  Removed
  2519 former Simplifier.inherit_bounds, which is already included here --
  2520 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2521 specify an explicit context using Simplifier.context/theory_context.
  2522 
  2523 * Simplifier/Classical Reasoner: more abstract interfaces
  2524 change_simpset/claset for modifying the simpset/claset reference of a
  2525 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2526 INCOMPATIBILITY.
  2527 
  2528 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2529 "Trueprop" etc.
  2530 
  2531 
  2532 *** System ***
  2533 
  2534 * settings: the default heap location within ISABELLE_HOME_USER now
  2535 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2536 Isabelle installations.
  2537 
  2538 * isabelle-process: option -S (secure mode) disables some critical
  2539 operations, notably runtime compilation and evaluation of ML source
  2540 code.
  2541 
  2542 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2543 
  2544 * Support for parallel execution, using native multicore support of
  2545 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2546 independent theories, according to the given theory header
  2547 specifications. The maximum number of worker threads is specified via
  2548 usedir option -M or the "max-threads" setting in Proof General. A
  2549 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2550 to 6 on a 8-core machine.  User-code needs to observe certain
  2551 guidelines for thread-safe programming, see appendix A in the Isar
  2552 Implementation manual.
  2553 
  2554 
  2555 
  2556 New in Isabelle2005 (October 2005)
  2557 ----------------------------------
  2558 
  2559 *** General ***
  2560 
  2561 * Theory headers: the new header syntax for Isar theories is
  2562 
  2563   theory <name>
  2564   imports <theory1> ... <theoryN>
  2565   uses <file1> ... <fileM>
  2566   begin
  2567 
  2568 where the 'uses' part is optional.  The previous syntax
  2569 
  2570   theory <name> = <theory1> + ... + <theoryN>:
  2571 
  2572 will disappear in the next release.  Use isatool fixheaders to convert
  2573 existing theory files.  Note that there is no change in ancient
  2574 non-Isar theories now, but these will disappear soon.
  2575 
  2576 * Theory loader: parent theories can now also be referred to via
  2577 relative and absolute paths.
  2578 
  2579 * Command 'find_theorems' searches for a list of criteria instead of a
  2580 list of constants. Known criteria are: intro, elim, dest, name:string,
  2581 simp:term, and any term. Criteria can be preceded by '-' to select
  2582 theorems that do not match. Intro, elim, dest select theorems that
  2583 match the current goal, name:s selects theorems whose fully qualified
  2584 name contain s, and simp:term selects all simplification rules whose
  2585 lhs match term.  Any other term is interpreted as pattern and selects
  2586 all theorems matching the pattern. Available in ProofGeneral under
  2587 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2588 
  2589   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2590 
  2591 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2592 matching the current goal as introduction rule and not having "HOL."
  2593 in their name (i.e. not being defined in theory HOL).
  2594 
  2595 * Command 'thms_containing' has been discontinued in favour of
  2596 'find_theorems'; INCOMPATIBILITY.
  2597 
  2598 * Communication with Proof General is now 8bit clean, which means that
  2599 Unicode text in UTF-8 encoding may be used within theory texts (both
  2600 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2601 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2602 
  2603   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2604   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2605 
  2606 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2607 Classical Reasoner.  Typical big applications run around 2 times
  2608 faster.
  2609 
  2610 
  2611 *** Document preparation ***
  2612 
  2613 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2614 of raw sources.  Only those symbols that do not require additional
  2615 LaTeX packages (depending on comments in isabellesym.sty) are
  2616 displayed properly, everything else is left verbatim.  isatool display
  2617 and isatool print are used as front ends (these are subject to the
  2618 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2619 
  2620 * Command tags control specific markup of certain regions of text,
  2621 notably folding and hiding.  Predefined tags include "theory" (for
  2622 theory begin and end), "proof" for proof commands, and "ML" for
  2623 commands involving ML code; the additional tags "visible" and
  2624 "invisible" are unused by default.  Users may give explicit tag
  2625 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2626 interpretation of tags is determined by the LaTeX job during document
  2627 preparation: see option -V of isatool usedir, or options -n and -t of
  2628 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2629 \isadroptag.
  2630 
  2631 Several document versions may be produced at the same time via isatool
  2632 usedir (the generated index.html will link all of them).  Typical
  2633 specifications include ''-V document=theory,proof,ML'' to present
  2634 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2635 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2636 these parts without any formal replacement text.  The Isabelle site
  2637 default settings produce ''document'' and ''outline'' versions as
  2638 specified above.
  2639 
  2640 * Several new antiquotations:
  2641 
  2642   @{term_type term} prints a term with its type annotated;
  2643 
  2644   @{typeof term} prints the type of a term;
  2645 
  2646   @{const const} is the same as @{term const}, but checks that the
  2647   argument is a known logical constant;
  2648 
  2649   @{term_style style term} and @{thm_style style thm} print a term or
  2650   theorem applying a "style" to it
  2651 
  2652   @{ML text}
  2653 
  2654 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2655 definitions, equations, inequations etc., 'concl' printing only the
  2656 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2657 to print the specified premise.  TermStyle.add_style provides an ML
  2658 interface for introducing further styles.  See also the "LaTeX Sugar"
  2659 document practical applications.  The ML antiquotation prints
  2660 type-checked ML expressions verbatim.
  2661 
  2662 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2663 and 'text' support optional locale specification '(in loc)', which
  2664 specifies the default context for interpreting antiquotations.  For
  2665 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2666 
  2667 * Option 'locale=NAME' of antiquotations specifies an alternative
  2668 context interpreting the subsequent argument.  For example: @{thm
  2669 [locale=lattice] inf_assoc}.
  2670 
  2671 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2672 a proof context.
  2673 
  2674 * Proper output of antiquotations for theory commands involving a
  2675 proof context (such as 'locale' or 'theorem (in loc) ...').
  2676 
  2677 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2678 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2679 
  2680 * isatool usedir: new option -C (default true) controls whether option
  2681 -D should include a copy of the original document directory; -C false
  2682 prevents unwanted effects such as copying of administrative CVS data.
  2683 
  2684 
  2685 *** Pure ***
  2686 
  2687 * Considerably improved version of 'constdefs' command.  Now performs
  2688 automatic type-inference of declared constants; additional support for
  2689 local structure declarations (cf. locales and HOL records), see also
  2690 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2691 sequential dependencies of definitions within a single 'constdefs'
  2692 section; moreover, the declared name needs to be an identifier.  If
  2693 all fails, consider to fall back on 'consts' and 'defs' separately.
  2694 
  2695 * Improved indexed syntax and implicit structures.  First of all,
  2696 indexed syntax provides a notational device for subscripted
  2697 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2698 expressions.  Secondly, in a local context with structure
  2699 declarations, number indexes \<^sub>n or the empty index (default
  2700 number 1) refer to a certain fixed variable implicitly; option
  2701 show_structs controls printing of implicit structures.  Typical
  2702 applications of these concepts involve record types and locales.
  2703 
  2704 * New command 'no_syntax' removes grammar declarations (and
  2705 translations) resulting from the given syntax specification, which is
  2706 interpreted in the same manner as for the 'syntax' command.
  2707 
  2708 * 'Advanced' translation functions (parse_translation etc.) may depend
  2709 on the signature of the theory context being presently used for
  2710 parsing/printing, see also isar-ref manual.
  2711 
  2712 * Improved 'oracle' command provides a type-safe interface to turn an
  2713 ML expression of type theory -> T -> term into a primitive rule of
  2714 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2715 is already included here); see also FOL/ex/IffExample.thy;
  2716 INCOMPATIBILITY.
  2717 
  2718 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2719 before); "cI" is no longer bound, use "c.intro" instead.
  2720 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2721 axclasses vs. locales.
  2722 
  2723 * Improved internal renaming of symbolic identifiers -- attach primes
  2724 instead of base 26 numbers.
  2725 
  2726 * New flag show_question_marks controls printing of leading question
  2727 marks in schematic variable names.
  2728 
  2729 * In schematic variable names, *any* symbol following \<^isub> or
  2730 \<^isup> is now treated as part of the base name.  For example, the
  2731 following works without printing of awkward ".0" indexes:
  2732 
  2733   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2734     by simp
  2735 
  2736 * Inner syntax includes (*(*nested*) comments*).
  2737 
  2738 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2739 annotations as "(00...)".
  2740 
  2741 * Clear separation of logical types and nonterminals, where the latter
  2742 may only occur in 'syntax' specifications or type abbreviations.
  2743 Before that distinction was only partially implemented via type class
  2744 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2745 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2746 exotic syntax specifications may require further adaption
  2747 (e.g. Cube/Cube.thy).
  2748 
  2749 * Removed obsolete type class "logic", use the top sort {} instead.
  2750 Note that non-logical types should be declared as 'nonterminals'
  2751 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2752 specifications.
  2753 
  2754 * Attributes 'induct' and 'cases': type or set names may now be
  2755 locally fixed variables as well.
  2756 
  2757 * Simplifier: can now control the depth to which conditional rewriting
  2758 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2759 Limit.
  2760 
  2761 * Simplifier: simplification procedures may now take the current
  2762 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2763 interface), which is very useful for calling the Simplifier
  2764 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2765 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2766 low-level mk_simproc no longer applies Logic.varify internally, to
  2767 allow for use in a context of fixed variables.
  2768 
  2769 * thin_tac now works even if the assumption being deleted contains !!
  2770 or ==>.  More generally, erule now works even if the major premise of
  2771 the elimination rule contains !! or ==>.
  2772 
  2773 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2774 
  2775 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2776 from Pure, which contains all common declarations already.  Both
  2777 theories are defined via plain Isabelle/Isar .thy files.
  2778 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2779 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2780 use isatool fixcpure to adapt your theory and ML sources.
  2781 
  2782 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2783 selections of theorems in named facts via index ranges.
  2784 
  2785 * 'print_theorems': in theory mode, really print the difference
  2786 wrt. the last state (works for interactive theory development only),
  2787 in proof mode print all local facts (cf. 'print_facts');
  2788 
  2789 * 'hide': option '(open)' hides only base names.
  2790 
  2791 * More efficient treatment of intermediate checkpoints in interactive
  2792 theory development.
  2793 
  2794 * Code generator is now invoked via code_module (incremental code
  2795 generation) and code_library (modular code generation, ML structures
  2796 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2797 must be quoted when used as identifiers.
  2798 
  2799 * New 'value' command for reading, evaluating and printing terms using
  2800 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2801 quoted when used as identifier.
  2802 
  2803 
  2804 *** Locales ***
  2805 
  2806 * New commands for the interpretation of locale expressions in
  2807 theories (1), locales (2) and proof contexts (3).  These generate
  2808 proof obligations from the expression specification.  After the
  2809 obligations have been discharged, theorems of the expression are added
  2810 to the theory, target locale or proof context.  The synopsis of the
  2811 commands is a follows:
  2812 
  2813   (1) interpretation expr inst
  2814   (2) interpretation target < expr
  2815   (3) interpret expr inst
  2816 
  2817 Interpretation in theories and proof contexts require a parameter
  2818 instantiation of terms from the current context.  This is applied to
  2819 specifications and theorems of the interpreted expression.
  2820 Interpretation in locales only permits parameter renaming through the
  2821 locale expression.  Interpretation is smart in that interpretations
  2822 that are active already do not occur in proof obligations, neither are
  2823 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2824 inspect active interpretations of a particular locale.  For details,
  2825 see the Isar Reference manual.  Examples can be found in
  2826 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2827 
  2828 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2829 'interpret' instead.
  2830 
  2831 * New context element 'constrains' for adding type constraints to
  2832 parameters.
  2833 
  2834 * Context expressions: renaming of parameters with syntax
  2835 redeclaration.
  2836 
  2837 * Locale declaration: 'includes' disallowed.
  2838 
  2839 * Proper static binding of attribute syntax -- i.e. types / terms /
  2840 facts mentioned as arguments are always those of the locale definition
  2841 context, independently of the context of later invocations.  Moreover,
  2842 locale operations (renaming and type / term instantiation) are applied
  2843 to attribute arguments as expected.
  2844 
  2845 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2846 actual attributes; rare situations may require Attrib.attribute to
  2847 embed those attributes into Attrib.src that lack concrete syntax.
  2848 Attribute implementations need to cooperate properly with the static
  2849 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2850 Attrib.XXX_thm etc. already do the right thing without further
  2851 intervention.  Only unusual applications -- such as "where" or "of"
  2852 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2853 on the context and the facts involved -- may have to assign parsed
  2854 values to argument tokens explicitly.
  2855 
  2856 * Changed parameter management in theorem generation for long goal
  2857 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2858 theorem statement in rare situations.
  2859 
  2860 * Locale inspection command 'print_locale' omits notes elements.  Use
  2861 'print_locale!' to have them included in the output.
  2862 
  2863 
  2864 *** Provers ***
  2865 
  2866 * Provers/hypsubst.ML: improved version of the subst method, for
  2867 single-step rewriting: it now works in bound variable contexts. New is
  2868 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2869 rewrite a different subterm than the original subst method, which is
  2870 still available as 'simplesubst'.
  2871 
  2872 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2873 and quasi orders.
  2874 
  2875 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2876 reflexive-transitive closure of relations.
  2877 
  2878 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2879 limit (previously hard-coded with a value of 20) user-definable.
  2880 
  2881 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2882 is peformed already.  Object-logics merely need to finish their
  2883 initial simpset configuration as before.  INCOMPATIBILITY.
  2884 
  2885 
  2886 *** HOL ***
  2887 
  2888 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2889 
  2890   syntax (epsilon)
  2891     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2892 
  2893 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2894 and x-symbol; use option '-m epsilon' to get it actually printed.
  2895 Moreover, the mathematically important symbolic identifier \<epsilon>
  2896 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2897 
  2898 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2899 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2900 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2901 support corresponding Isar calculations.
  2902 
  2903 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2904 instead of ":".
  2905 
  2906 * theory SetInterval: changed the syntax for open intervals:
  2907 
  2908   Old       New
  2909   {..n(}    {..<n}
  2910   {)n..}    {n<..}
  2911   {m..n(}   {m..<n}
  2912   {)m..n}   {m<..n}
  2913   {)m..n(}  {m<..<n}
  2914 
  2915 The old syntax is still supported but will disappear in the next
  2916 release.  For conversion use the following Emacs search and replace
  2917 patterns (these are not perfect but work quite well):
  2918 
  2919   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2920   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2921 
  2922 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2923 equalities in commutative rings; method 'algebra' provides a generic
  2924 interface.
  2925 
  2926 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2927 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2928 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2929 be a tuple pattern.
  2930 
  2931 Some new syntax forms are available:
  2932 
  2933   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2934   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2935   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2936   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2937 
  2938 The latter form "\<Sum>x < k. e" used to be based on a separate
  2939 function "Summation", which has been discontinued.
  2940 
  2941 * theory Finite_Set: in structured induction proofs, the insert case
  2942 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2943 (insert F x)'.
  2944 
  2945 * The 'refute' command has been extended to support a much larger
  2946 fragment of HOL, including axiomatic type classes, constdefs and
  2947 typedefs, inductive datatypes and recursion.
  2948 
  2949 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2950 Requires zChaff with proof generation to be installed.  See
  2951 HOL/ex/SAT_Examples.thy for examples.
  2952 
  2953 * Datatype induction via method 'induct' now preserves the name of the
  2954 induction variable. For example, when proving P(xs::'a list) by
  2955 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2956 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2957 in unstructured proof scripts.
  2958 
  2959 * Reworked implementation of records.  Improved scalability for
  2960 records with many fields, avoiding performance problems for type
  2961 inference. Records are no longer composed of nested field types, but
  2962 of nested extension types. Therefore the record type only grows linear
  2963 in the number of extensions and not in the number of fields.  The
  2964 top-level (users) view on records is preserved.  Potential
  2965 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2966 old record representation. The type generated for a record is called
  2967 <record_name>_ext_type.
  2968 
  2969 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2970 proofs triggered by a record definition or a simproc (if
  2971 quick_and_dirty is enabled).  Definitions of large records can take
  2972 quite long.
  2973 
  2974 New simproc record_upd_simproc for simplification of multiple record
  2975 updates enabled by default.  Moreover, trivial updates are also
  2976 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2977 occasionally, since simplification is more powerful by default.
  2978 
  2979 * typedef: proper support for polymorphic sets, which contain extra
  2980 type-variables in the term.
  2981 
  2982 * Simplifier: automatically reasons about transitivity chains
  2983 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2984 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2985 old proofs break occasionally as simplification may now solve more
  2986 goals than previously.
  2987 
  2988 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2989 present.  Works for all partial orders (class "order"), in particular
  2990 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2991 just like y <= x.
  2992 
  2993 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2994 bound variable or a constant then the let is unfolded.  Otherwise
  2995 first a is simplified to b, and then f b is simplified to g. If
  2996 possible we abstract b from g arriving at "let x = b in h x",
  2997 otherwise we unfold the let and arrive at g.  The simproc can be
  2998 enabled/disabled by the reference use_let_simproc.  Potential
  2999 INCOMPATIBILITY since simplification is more powerful by default.
  3000 
  3001 * Classical reasoning: the meson method now accepts theorems as arguments.
  3002 
  3003 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3004 jobs to provide advice on the provability of subgoals.
  3005 
  3006 * Theory OrderedGroup and Ring_and_Field: various additions and
  3007 improvements to faciliate calculations involving equalities and
  3008 inequalities.
  3009 
  3010 The following theorems have been eliminated or modified
  3011 (INCOMPATIBILITY):
  3012 
  3013   abs_eq             now named abs_of_nonneg
  3014   abs_of_ge_0        now named abs_of_nonneg
  3015   abs_minus_eq       now named abs_of_nonpos
  3016   imp_abs_id         now named abs_of_nonneg
  3017   imp_abs_neg_id     now named abs_of_nonpos
  3018   mult_pos           now named mult_pos_pos
  3019   mult_pos_le        now named mult_nonneg_nonneg
  3020   mult_pos_neg_le    now named mult_nonneg_nonpos
  3021   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3022   mult_neg           now named mult_neg_neg
  3023   mult_neg_le        now named mult_nonpos_nonpos
  3024 
  3025 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3026      
  3027      zero_le_square
  3028      not_square_less_zero 
  3029 
  3030   The following lemmas have been deleted from Real/RealPow:
  3031   
  3032      realpow_zero_zero
  3033      realpow_two
  3034      realpow_less
  3035      zero_le_power
  3036      realpow_two_le
  3037      abs_realpow_two
  3038      realpow_two_abs     
  3039 
  3040 * Theory Parity: added rules for simplifying exponents.
  3041 
  3042 * Theory List:
  3043 
  3044 The following theorems have been eliminated or modified
  3045 (INCOMPATIBILITY):
  3046 
  3047   list_all_Nil       now named list_all.simps(1)
  3048   list_all_Cons      now named list_all.simps(2)
  3049   list_all_conv      now named list_all_iff
  3050   set_mem_eq         now named mem_iff
  3051 
  3052 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3053 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3054 
  3055 
  3056 *** HOL-Complex ***
  3057 
  3058 * Theory RealDef: better support for embedding natural numbers and
  3059 integers in the reals.
  3060 
  3061 The following theorems have been eliminated or modified
  3062 (INCOMPATIBILITY):
  3063 
  3064   exp_ge_add_one_self  now requires no hypotheses
  3065   real_of_int_add      reversed direction of equality (use [symmetric])
  3066   real_of_int_minus    reversed direction of equality (use [symmetric])
  3067   real_of_int_diff     reversed direction of equality (use [symmetric])
  3068   real_of_int_mult     reversed direction of equality (use [symmetric])
  3069 
  3070 * Theory RComplete: expanded support for floor and ceiling functions.
  3071 
  3072 * Theory Ln is new, with properties of the natural logarithm
  3073 
  3074 * Hyperreal: There is a new type constructor "star" for making
  3075 nonstandard types.  The old type names are now type synonyms:
  3076 
  3077   hypreal = real star
  3078   hypnat = nat star
  3079   hcomplex = complex star
  3080 
  3081 * Hyperreal: Many groups of similarly-defined constants have been
  3082 replaced by polymorphic versions (INCOMPATIBILITY):
  3083 
  3084   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3085 
  3086   starset      <-- starsetNat, starsetC
  3087   *s*          <-- *sNat*, *sc*
  3088   starset_n    <-- starsetNat_n, starsetC_n
  3089   *sn*         <-- *sNatn*, *scn*
  3090   InternalSets <-- InternalNatSets, InternalCSets
  3091 
  3092   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3093   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3094   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3095   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3096   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3097 
  3098 * Hyperreal: Many type-specific theorems have been removed in favor of
  3099 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3100 
  3101   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3102   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3103   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3104   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3105   right_minus <-- hypreal_add_minus
  3106   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3107   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3108   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3109   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3110   mult_1_right <-- hcomplex_mult_one_right
  3111   mult_zero_left <-- hcomplex_mult_zero_left
  3112   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3113   right_distrib <-- hypnat_add_mult_distrib2
  3114   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3115   right_inverse <-- hypreal_mult_inverse
  3116   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3117   order_refl <-- {hypreal,hypnat}_le_refl
  3118   order_trans <-- {hypreal,hypnat}_le_trans
  3119   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3120   order_less_le <-- {hypreal,hypnat}_less_le
  3121   linorder_linear <-- {hypreal,hypnat}_le_linear
  3122   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3123   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3124   add_nonneg_nonneg <-- hypreal_le_add_order
  3125 
  3126 * Hyperreal: Separate theorems having to do with type-specific
  3127 versions of constants have been merged into theorems that apply to the
  3128 new polymorphic constants (INCOMPATIBILITY):
  3129 
  3130   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3131   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3132   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3133   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3134   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3135   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3136   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3137   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3138   STAR_diff <-- {STAR,STARC}_diff
  3139   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3140     STARC_hcomplex_of_complex}_image_subset
  3141   starset_n_Un <-- starset{Nat,C}_n_Un
  3142   starset_n_Int <-- starset{Nat,C}_n_Int
  3143   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3144   starset_n_diff <-- starset{Nat,C}_n_diff
  3145   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3146   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3147   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3148   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3149   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3150   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3151   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3152   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3153   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3154   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3155   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3156   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3157   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3158   starfun_diff <-- starfun{C,RC,CR}_diff
  3159   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3160   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3161   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3162   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3163   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3164   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3165   starfun_Id <-- starfunC_Id
  3166   starfun_approx <-- starfun{Nat,CR}_approx
  3167   starfun_capprox <-- starfun{C,RC}_capprox
  3168   starfun_abs <-- starfunNat_rabs
  3169   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3170   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3171   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3172   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3173   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3174   starfun_add_approx <-- starfunCR_add_approx
  3175   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3176   starfun_divide <-- starfun{C,CR,RC}_divide
  3177   starfun_n <-- starfun{Nat,C}_n
  3178   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3179   starfun_n_add <-- starfun{Nat,C}_n_add
  3180   starfun_n_add_minus <-- starfunNat_n_add_minus
  3181   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3182   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3183   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3184 
  3185   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3186   star_n_minus <-- {hypreal,hcomplex}_minus
  3187   star_n_diff <-- {hypreal,hcomplex}_diff
  3188   star_n_mult <-- {hypreal,hcomplex}_mult
  3189   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3190   star_n_le <-- {hypreal,hypnat}_le
  3191   star_n_less <-- {hypreal,hypnat}_less
  3192   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3193   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3194   star_n_abs <-- hypreal_hrabs
  3195   star_n_divide <-- hcomplex_divide
  3196 
  3197   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3198   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3199   star_of_diff <-- hypreal_of_real_diff
  3200   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3201   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3202   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3203   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3204   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3205   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3206   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3207   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3208   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3209   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3210   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3211   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3212   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3213   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3214   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3215   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3216   star_of_power <-- hypreal_of_real_power
  3217   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3218 
  3219 * Hyperreal: new method "transfer" that implements the transfer
  3220 principle of nonstandard analysis. With a subgoal that mentions
  3221 nonstandard types like "'a star", the command "apply transfer"
  3222 replaces it with an equivalent one that mentions only standard types.
  3223 To be successful, all free variables must have standard types; non-
  3224 standard variables must have explicit universal quantifiers.
  3225 
  3226 * Hyperreal: A theory of Taylor series.
  3227 
  3228 
  3229 *** HOLCF ***
  3230 
  3231 * Discontinued special version of 'constdefs' (which used to support
  3232 continuous functions) in favor of the general Pure one with full
  3233 type-inference.
  3234 
  3235 * New simplification procedure for solving continuity conditions; it
  3236 is much faster on terms with many nested lambda abstractions (cubic
  3237 instead of exponential time).
  3238 
  3239 * New syntax for domain package: selector names are now optional.
  3240 Parentheses should be omitted unless argument is lazy, for example:
  3241 
  3242   domain 'a stream = cons "'a" (lazy "'a stream")
  3243 
  3244 * New command 'fixrec' for defining recursive functions with pattern
  3245 matching; defining multiple functions with mutual recursion is also
  3246 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3247 sinr, or any data constructor defined by the domain package. The given
  3248 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3249 syntax and examples.
  3250 
  3251 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3252 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3253 but the proof obligation additionally includes an admissibility
  3254 requirement. The packages generate instances of class cpo or pcpo,
  3255 with continuity and strictness theorems for Rep and Abs.
  3256 
  3257 * HOLCF: Many theorems have been renamed according to a more standard naming
  3258 scheme (INCOMPATIBILITY):
  3259 
  3260   foo_inject:  "foo$x = foo$y ==> x = y"
  3261   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3262   foo_less:    "(foo$x << foo$y) = (x << y)"
  3263   foo_strict:  "foo$UU = UU"
  3264   foo_defined: "... ==> foo$x ~= UU"
  3265   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3266 
  3267 
  3268 *** ZF ***
  3269 
  3270 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3271 including the First Isomorphism Theorem (on quotienting by the kernel
  3272 of a homomorphism).
  3273 
  3274 * ZF/Simplifier: install second copy of type solver that actually
  3275 makes use of TC rules declared to Isar proof contexts (or locales);
  3276 the old version is still required for ML proof scripts.
  3277 
  3278 
  3279 *** Cube ***
  3280 
  3281 * Converted to Isar theory format; use locales instead of axiomatic
  3282 theories.
  3283 
  3284 
  3285 *** ML ***
  3286 
  3287 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3288 for ||>, ||>>, |>>,
  3289 
  3290 * Pure/library.ML no longer defines its own option datatype, but uses
  3291 that of the SML basis, which has constructors NONE and SOME instead of
  3292 None and Some, as well as exception Option.Option instead of OPTION.
  3293 The functions the, if_none, is_some, is_none have been adapted
  3294 accordingly, while Option.map replaces apsome.
  3295 
  3296 * Pure/library.ML: the exception LIST has been given up in favour of
  3297 the standard exceptions Empty and Subscript, as well as
  3298 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3299 superceded by the standard hd and tl functions etc.
  3300 
  3301 A number of basic list functions are no longer exported to the ML
  3302 toplevel, as they are variants of predefined functions.  The following
  3303 suggests how one can translate existing code:
  3304 
  3305     rev_append xs ys = List.revAppend (xs, ys)
  3306     nth_elem (i, xs) = List.nth (xs, i)
  3307     last_elem xs = List.last xs
  3308     flat xss = List.concat xss
  3309     seq fs = List.app fs
  3310     partition P xs = List.partition P xs
  3311     mapfilter f xs = List.mapPartial f xs
  3312 
  3313 * Pure/library.ML: several combinators for linear functional
  3314 transformations, notably reverse application and composition:
  3315 
  3316   x |> f                f #> g
  3317   (x, y) |-> f          f #-> g
  3318 
  3319 * Pure/library.ML: introduced/changed precedence of infix operators:
  3320 
  3321   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3322   infix 2 ?;
  3323   infix 3 o oo ooo oooo;
  3324   infix 4 ~~ upto downto;
  3325 
  3326 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3327 infix operators.
  3328 
  3329 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3330 fold_map support linear functional transformations and nesting.  For
  3331 example:
  3332 
  3333   fold f [x1, ..., xN] y =
  3334     y |> f x1 |> ... |> f xN
  3335 
  3336   (fold o fold) f [xs1, ..., xsN] y =
  3337     y |> fold f xs1 |> ... |> fold f xsN
  3338 
  3339   fold f [x1, ..., xN] =
  3340     f x1 #> ... #> f xN
  3341 
  3342   (fold o fold) f [xs1, ..., xsN] =
  3343     fold f xs1 #> ... #> fold f xsN
  3344 
  3345 * Pure/library.ML: the following selectors on type 'a option are
  3346 available:
  3347 
  3348   the:               'a option -> 'a  (*partial*)
  3349   these:             'a option -> 'a  where 'a = 'b list
  3350   the_default: 'a -> 'a option -> 'a
  3351   the_list:          'a option -> 'a list
  3352 
  3353 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3354 basic operations for association lists, following natural argument
  3355 order; moreover the explicit equality predicate passed here avoids
  3356 potentially expensive polymorphic runtime equality checks.
  3357 The old functions may be expressed as follows:
  3358 
  3359   assoc = uncurry (AList.lookup (op =))
  3360   assocs = these oo AList.lookup (op =)
  3361   overwrite = uncurry (AList.update (op =)) o swap
  3362 
  3363 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3364 
  3365   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3366   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3367 
  3368 replacing make_keylist and keyfilter (occassionally used)
  3369 Naive rewrites:
  3370 
  3371   make_keylist = AList.make
  3372   keyfilter = AList.find (op =)
  3373 
  3374 * eq_fst and eq_snd now take explicit equality parameter, thus
  3375   avoiding eqtypes. Naive rewrites:
  3376 
  3377     eq_fst = eq_fst (op =)
  3378     eq_snd = eq_snd (op =)
  3379 
  3380 * Removed deprecated apl and apr (rarely used).
  3381   Naive rewrites:
  3382 
  3383     apl (n, op) =>>= curry op n
  3384     apr (op, m) =>>= fn n => op (n, m)
  3385 
  3386 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3387 provides a reasonably efficient light-weight implementation of sets as
  3388 lists.
  3389 
  3390 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3391 few new operations; existing lookup and update are now curried to
  3392 follow natural argument order (for use with fold etc.);
  3393 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3394 
  3395 * Pure/General: output via the Isabelle channels of
  3396 writeln/warning/error etc. is now passed through Output.output, with a
  3397 hook for arbitrary transformations depending on the print_mode
  3398 (cf. Output.add_mode -- the first active mode that provides a output
  3399 function wins).  Already formatted output may be embedded into further
  3400 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3401 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3402 accommodate easy composition of diagnostic messages etc.  Programmers
  3403 rarely need to care about Output.output or Output.raw at all, with
  3404 some notable exceptions: Output.output is required when bypassing the
  3405 standard channels (writeln etc.), or in token translations to produce
  3406 properly formatted results; Output.raw is required when capturing
  3407 already output material that will eventually be presented to the user
  3408 a second time.  For the default print mode, both Output.output and
  3409 Output.raw have no effect.
  3410 
  3411 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3412 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3413 cumulative results are displayed at the end of a batch session.
  3414 
  3415 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3416 replaced by File.platform_path and File.shell_path (with appropriate
  3417 hooks).  This provides a clean interface for unusual systems where the
  3418 internal and external process view of file names are different.
  3419 
  3420 * Pure: more efficient orders for basic syntactic entities: added
  3421 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3422 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3423 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3424 orders now -- potential INCOMPATIBILITY for code that depends on a
  3425 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3426 Library.sort_strings on result).
  3427 
  3428 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3429 fold_types traverse types/terms from left to right, observing natural
  3430 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3431 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3432 
  3433 * Pure: name spaces have been refined, with significant changes of the
  3434 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3435 to extern(_table).  The plain name entry path is superceded by a
  3436 general 'naming' context, which also includes the 'policy' to produce
  3437 a fully qualified name and external accesses of a fully qualified
  3438 name; NameSpace.extend is superceded by context dependent
  3439 Sign.declare_name.  Several theory and proof context operations modify
  3440 the naming context.  Especially note Theory.restore_naming and
  3441 ProofContext.restore_naming to get back to a sane state; note that
  3442 Theory.add_path is no longer sufficient to recover from
  3443 Theory.absolute_path in particular.
  3444 
  3445 * Pure: new flags short_names (default false) and unique_names
  3446 (default true) for controlling output of qualified names.  If
  3447 short_names is set, names are printed unqualified.  If unique_names is
  3448 reset, the name prefix is reduced to the minimum required to achieve
  3449 the original result when interning again, even if there is an overlap
  3450 with earlier declarations.
  3451 
  3452 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3453 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3454 (useful for printing error messages).  INCOMPATIBILITY.
  3455 
  3456 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3457 Theory.theory are now identified, referring to the universal
  3458 Context.theory (see Pure/context.ML).  Actual signature and theory
  3459 content is managed as theory data.  The old code and interfaces were
  3460 spread over many files and structures; the new arrangement introduces
  3461 considerable INCOMPATIBILITY to gain more clarity:
  3462 
  3463   Context -- theory management operations (name, identity, inclusion,
  3464     parents, ancestors, merge, etc.), plus generic theory data;
  3465 
  3466   Sign -- logical signature and syntax operations (declaring consts,
  3467     types, etc.), plus certify/read for common entities;
  3468 
  3469   Theory -- logical theory operations (stating axioms, definitions,
  3470     oracles), plus a copy of logical signature operations (consts,
  3471     types, etc.); also a few basic management operations (Theory.copy,
  3472     Theory.merge, etc.)
  3473 
  3474 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3475 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3476 for convenience -- they merely return the theory.
  3477 
  3478 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3479 
  3480 * Pure: the Isar proof context type is already defined early in Pure
  3481 as Context.proof (note that ProofContext.context and Proof.context are
  3482 aliases, where the latter is the preferred name).  This enables other
  3483 Isabelle components to refer to that type even before Isar is present.
  3484 
  3485 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3486 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3487 any of these kinds.  For example, Sign.intern typeK is now
  3488 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3489 Theory.hide_types.  Also note that former
  3490 Theory.hide_classes/types/consts are now
  3491 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3492 internalize their arguments!  INCOMPATIBILITY.
  3493 
  3494 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3495 datatype thmref (with constructors Name and NameSelection) instead of
  3496 plain string -- INCOMPATIBILITY;
  3497 
  3498 * Pure: cases produced by proof methods specify options, where NONE
  3499 means to remove case bindings -- INCOMPATIBILITY in
  3500 (RAW_)METHOD_CASES.
  3501 
  3502 * Pure: the following operations retrieve axioms or theorems from a
  3503 theory node or theory hierarchy, respectively:
  3504 
  3505   Theory.axioms_of: theory -> (string * term) list
  3506   Theory.all_axioms_of: theory -> (string * term) list
  3507   PureThy.thms_of: theory -> (string * thm) list
  3508   PureThy.all_thms_of: theory -> (string * thm) list
  3509 
  3510 * Pure: print_tac now outputs the goal through the trace channel.
  3511 
  3512 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3513 Reference Toplevel.debug (default false) controls detailed printing
  3514 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3515 controls execution profiling -- set to 1 for time and 2 for space
  3516 (both increase the runtime).
  3517 
  3518 * Isar session: The initial use of ROOT.ML is now always timed,
  3519 i.e. the log will show the actual process times, in contrast to the
  3520 elapsed wall-clock time that the outer shell wrapper produces.
  3521 
  3522 * Simplifier: improved handling of bound variables (nameless
  3523 representation, avoid allocating new strings).  Simprocs that invoke
  3524 the Simplifier recursively should use Simplifier.inherit_bounds to
  3525 avoid local name clashes.  Failure to do so produces warnings
  3526 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3527 for further details.
  3528 
  3529 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3530 bindings for all theorems stored within a given theory; this may help
  3531 in porting non-Isar theories to Isar ones, while keeping ML proof
  3532 scripts for the time being.
  3533 
  3534 * ML operator HTML.with_charset specifies the charset begin used for
  3535 generated HTML files.  For example:
  3536 
  3537   HTML.with_charset "utf-8" use_thy "Hebrew";
  3538   HTML.with_charset "utf-8" use_thy "Chinese";
  3539 
  3540 
  3541 *** System ***
  3542 
  3543 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3544 isabelle, isatool etc.).
  3545 
  3546 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3547 isatool doc, isatool mkdir, display_drafts etc.).
  3548 
  3549 * isatool usedir: option -f allows specification of the ML file to be
  3550 used by Isabelle; default is ROOT.ML.
  3551 
  3552 * New isatool version outputs the version identifier of the Isabelle
  3553 distribution being used.
  3554 
  3555 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3556 (containing Boolean satisfiability problems) into Isabelle/HOL
  3557 theories.
  3558 
  3559 
  3560 
  3561 New in Isabelle2004 (April 2004)
  3562 --------------------------------
  3563 
  3564 *** General ***
  3565 
  3566 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3567   Replaces linorder.ML.
  3568 
  3569 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3570   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3571   (\<a>...\<z>), are now considered normal letters, and can therefore
  3572   be used anywhere where an ASCII letter (a...zA...Z) has until
  3573   now. COMPATIBILITY: This obviously changes the parsing of some
  3574   terms, especially where a symbol has been used as a binder, say
  3575   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3576   as an identifier.  Fix it by inserting a space around former
  3577   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3578   existing theory and ML files.
  3579 
  3580 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3581 
  3582 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3583   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3584   a normal (but invisible) letter. For multiple letter subscripts repeat
  3585   \<^isub> like this: x\<^isub>1\<^isub>2.
  3586 
  3587 * Pure: There are now sub-/superscripts that can span more than one
  3588   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3589   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3590   superscript. The new control characters are not identifier parts.
  3591 
  3592 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3593   content of "..." to the latex file instead of \isacntrl... . The "..."
  3594   may consist of any printable characters excluding the end bracket >.
  3595 
  3596 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3597   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3598   declare constants "final", which prevents their being given a definition
  3599   later.  It is useful for constants whose behaviour is fixed axiomatically
  3600   rather than definitionally, such as the meta-logic connectives.
  3601 
  3602 * Pure: 'instance' now handles general arities with general sorts
  3603   (i.e. intersections of classes),
  3604 
  3605 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3606   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3607   It can be changed to alter the colors/layout of generated pages.
  3608 
  3609 
  3610 *** Isar ***
  3611 
  3612 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3613   cut_tac, subgoal_tac and thin_tac:
  3614   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3615     locales are no longer forced to write Isar proof scripts.
  3616     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3617     emulations.
  3618   - INCOMPATIBILITY: names of variables to be instantiated may no
  3619     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3620     This is consistent with the instantiation attribute "where".
  3621 
  3622 * Attributes "where" and "of":
  3623   - Now take type variables of instantiated theorem into account when reading
  3624     the instantiation string.  This fixes a bug that caused instantiated
  3625     theorems to have too special types in some circumstances.
  3626   - "where" permits explicit instantiations of type variables.
  3627 
  3628 * Calculation commands "moreover" and "also" no longer interfere with
  3629   current facts ("this"), admitting arbitrary combinations with "then"
  3630   and derived forms.
  3631 
  3632 * Locales:
  3633   - Goal statements involving the context element "includes" no longer
  3634     generate theorems with internal delta predicates (those ending on
  3635     "_axioms") in the premise.
  3636     Resolve particular premise with <locale>.intro to obtain old form.
  3637   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3638     specification and "includes" elements in goal statement.
  3639   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3640     [intro?] and [elim?] (respectively) by default.
  3641   - Experimental command for instantiation of locales in proof contexts:
  3642         instantiate <label>[<attrs>]: <loc>
  3643     Instantiates locale <loc> and adds all its theorems to the current context
  3644     taking into account their attributes.  Label and attrs are optional
  3645     modifiers, like in theorem declarations.  If present, names of
  3646     instantiated theorems are qualified with <label>, and the attributes
  3647     <attrs> are applied after any attributes these theorems might have already.
  3648       If the locale has assumptions, a chained fact of the form
  3649     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3650     are derived.  The command does not support old-style locales declared
  3651     with "locale (open)".
  3652       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3653 
  3654 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3655   (Isar) contexts.
  3656 
  3657 
  3658 *** HOL ***
  3659 
  3660 * Proof import: new image HOL4 contains the imported library from
  3661   the HOL4 system with about 2500 theorems. It is imported by
  3662   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3663   can be used like any other Isabelle image.  See
  3664   HOL/Import/HOL/README for more information.
  3665 
  3666 * Simplifier:
  3667   - Much improved handling of linear and partial orders.
  3668     Reasoners for linear and partial orders are set up for type classes
  3669     "linorder" and "order" respectively, and are added to the default simpset
  3670     as solvers.  This means that the simplifier can build transitivity chains
  3671     to solve goals from the assumptions.
  3672   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3673     of blast or auto after simplification become unnecessary because the goal
  3674     is solved by simplification already.
  3675 
  3676 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3677     all proved in axiomatic type classes for semirings, rings and fields.
  3678 
  3679 * Numerics:
  3680   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3681     now formalized using the Ring_and_Field theory mentioned above.
  3682   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3683     than before, because now they are set up once in a generic manner.
  3684   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3685     Look for the general versions in Ring_and_Field (and Power if they concern
  3686     exponentiation).
  3687 
  3688 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3689 
  3690 * Records:
  3691   - Record types are now by default printed with their type abbreviation
  3692     instead of the list of all field types. This can be configured via
  3693     the reference "print_record_type_abbr".
  3694   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3695     (not enabled by default).
  3696   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3697     EX x. x = sel r to True (not enabled by default).
  3698   - Tactic "record_split_simp_tac" to split and simplify records added.
  3699 
  3700 * 'specification' command added, allowing for definition by
  3701   specification.  There is also an 'ax_specification' command that
  3702   introduces the new constants axiomatically.
  3703 
  3704 * arith(_tac) is now able to generate counterexamples for reals as well.
  3705 
  3706 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3707 
  3708 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3709   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3710 
  3711 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3712   matrix theory to linear programming.
  3713 
  3714 * Unions and Intersections:
  3715   The latex output syntax of UN and INT has been changed
  3716   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3717   i.e. the index formulae has become a subscript.
  3718   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3719 
  3720 * Unions and Intersections over Intervals:
  3721   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3722   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3723   like in normal math, and corresponding versions for < and for intersection.
  3724 
  3725 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3726   lexicographic dictonary ordering has been added as "lexord".
  3727 
  3728 * ML: the legacy theory structures Int and List have been removed. They had
  3729   conflicted with ML Basis Library structures having the same names.
  3730 
  3731 * 'refute' command added to search for (finite) countermodels.  Only works
  3732   for a fragment of HOL.  The installation of an external SAT solver is
  3733   highly recommended.  See "HOL/Refute.thy" for details.
  3734 
  3735 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3736   formulae under an assignment of free variables to random values.
  3737   In contrast to 'refute', it can deal with inductive datatypes,
  3738   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3739   for examples.
  3740 
  3741 
  3742 *** HOLCF ***
  3743 
  3744 * Streams now come with concatenation and are part of the HOLCF image
  3745 
  3746 
  3747 
  3748 New in Isabelle2003 (May 2003)
  3749 ------------------------------
  3750 
  3751 *** General ***
  3752 
  3753 * Provers/simplifier:
  3754 
  3755   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3756     Assumptions are now subject to complete mutual simplification,
  3757     not just from left to right. The simplifier now preserves
  3758     the order of assumptions.
  3759 
  3760     Potential INCOMPATIBILITY:
  3761 
  3762     -- simp sometimes diverges where the old version did
  3763        not, e.g. invoking simp on the goal
  3764 
  3765         [| P (f x); y = x; f x = f y |] ==> Q
  3766 
  3767        now gives rise to the infinite reduction sequence
  3768 
  3769         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3770 
  3771        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3772        kind of problem.
  3773 
  3774     -- Tactics combining classical reasoner and simplification (such as auto)
  3775        are also affected by this change, because many of them rely on
  3776        simp. They may sometimes diverge as well or yield a different numbers
  3777        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3778        in case of problems. Sometimes subsequent calls to the classical
  3779        reasoner will fail because a preceeding call to the simplifier too
  3780        eagerly simplified the goal, e.g. deleted redundant premises.
  3781 
  3782   - The simplifier trace now shows the names of the applied rewrite rules
  3783 
  3784   - You can limit the number of recursive invocations of the simplifier
  3785     during conditional rewriting (where the simplifie tries to solve the
  3786     conditions before applying the rewrite rule):
  3787     ML "simp_depth_limit := n"
  3788     where n is an integer. Thus you can force termination where previously
  3789     the simplifier would diverge.
  3790 
  3791   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3792 
  3793   - No longer aborts on failed congruence proof.  Instead, the
  3794     congruence is ignored.
  3795 
  3796 * Pure: New generic framework for extracting programs from constructive
  3797   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3798   as HOL/Extraction for some case studies.
  3799 
  3800 * Pure: The main goal of the proof state is no longer shown by default, only
  3801 the subgoals. This behaviour is controlled by a new flag.
  3802    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3803 (ML: Proof.show_main_goal).
  3804 
  3805 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3806 rules whose conclusion matches subgoal 1:
  3807       PG menu: Isabelle/Isar -> Show me -> matching rules
  3808 The rules are ordered by how closely they match the subgoal.
  3809 In particular, rules that solve a subgoal outright are displayed first
  3810 (or rather last, the way they are printed).
  3811 (ML: ProofGeneral.print_intros())
  3812 
  3813 * Pure: New flag trace_unify_fail causes unification to print
  3814 diagnostic information (PG: in trace buffer) when it fails. This is
  3815 useful for figuring out why single step proofs like rule, erule or
  3816 assumption failed.
  3817 
  3818 * Pure: Locale specifications now produce predicate definitions
  3819 according to the body of text (covering assumptions modulo local
  3820 definitions); predicate "loc_axioms" covers newly introduced text,
  3821 while "loc" is cumulative wrt. all included locale expressions; the
  3822 latter view is presented only on export into the global theory
  3823 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3824 on the old view without predicates;
  3825 
  3826 * Pure: predefined locales "var" and "struct" are useful for sharing
  3827 parameters (as in CASL, for example); just specify something like
  3828 ``var x + var y + struct M'' as import;
  3829 
  3830 * Pure: improved thms_containing: proper indexing of facts instead of
  3831 raw theorems; check validity of results wrt. current name space;
  3832 include local facts of proof configuration (also covers active
  3833 locales), cover fixed variables in index; may use "_" in term
  3834 specification; an optional limit for the number of printed facts may
  3835 be given (the default is 40);
  3836 
  3837 * Pure: disallow duplicate fact bindings within new-style theory files
  3838 (batch-mode only);
  3839 
  3840 * Provers: improved induct method: assumptions introduced by case
  3841 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3842 the goal statement); "foo" still refers to all facts collectively;
  3843 
  3844 * Provers: the function blast.overloaded has been removed: all constants
  3845 are regarded as potentially overloaded, which improves robustness in exchange
  3846 for slight decrease in efficiency;
  3847 
  3848 * Provers/linorder: New generic prover for transitivity reasoning over
  3849 linear orders.  Note: this prover is not efficient!
  3850 
  3851 * Isar: preview of problems to finish 'show' now produce an error
  3852 rather than just a warning (in interactive mode);
  3853 
  3854 
  3855 *** HOL ***
  3856 
  3857 * arith(_tac)
  3858 
  3859  - Produces a counter example if it cannot prove a goal.
  3860    Note that the counter example may be spurious if the goal is not a formula
  3861    of quantifier-free linear arithmetic.
  3862    In ProofGeneral the counter example appears in the trace buffer.
  3863 
  3864  - Knows about div k and mod k where k is a numeral of type nat or int.
  3865 
  3866  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3867    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3868    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3869 
  3870 * simp's arithmetic capabilities have been enhanced a bit: it now
  3871 takes ~= in premises into account (by performing a case split);
  3872 
  3873 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3874 are distributed over a sum of terms;
  3875 
  3876 * New tactic "trans_tac" and method "trans" instantiate
  3877 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3878 "<=", "<" and "=").
  3879 
  3880 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3881 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3882 
  3883 * 'typedef' command has new option "open" to suppress the set
  3884 definition;
  3885 
  3886 * functions Min and Max on finite sets have been introduced (theory
  3887 Finite_Set);
  3888 
  3889 * attribute [symmetric] now works for relations as well; it turns
  3890 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3891 
  3892 * induct over a !!-quantified statement (say !!x1..xn):
  3893   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3894 
  3895 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3896 %x. None. Warning: empty_def now refers to the previously hidden definition
  3897 of the empty set.
  3898 
  3899 * Algebra: formalization of classical algebra.  Intended as base for
  3900 any algebraic development in Isabelle.  Currently covers group theory
  3901 (up to Sylow's theorem) and ring theory (Universal Property of
  3902 Univariate Polynomials).  Contributions welcome;
  3903 
  3904 * GroupTheory: deleted, since its material has been moved to Algebra;
  3905 
  3906 * Complex: new directory of the complex numbers with numeric constants,
  3907 nonstandard complex numbers, and some complex analysis, standard and
  3908 nonstandard (Jacques Fleuriot);
  3909 
  3910 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3911 
  3912 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3913 Fleuriot);
  3914 
  3915 * Real/HahnBanach: updated and adapted to locales;
  3916 
  3917 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3918 Gray and Kramer);
  3919 
  3920 * UNITY: added the Meier-Sanders theory of progress sets;
  3921 
  3922 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3923 as abstract algorithms, instantiated to the JVM;
  3924 
  3925 * Bali: Java source language formalization. Type system, operational
  3926 semantics, axiomatic semantics. Supported language features:
  3927 classes, interfaces, objects,virtual methods, static methods,
  3928 static/instance fields, arrays, access modifiers, definite
  3929 assignment, exceptions.
  3930 
  3931 
  3932 *** ZF ***
  3933 
  3934 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3935 universe, etc.);
  3936 
  3937 * Main ZF: virtually all theories converted to new-style format;
  3938 
  3939 
  3940 *** ML ***
  3941 
  3942 * Pure: Tactic.prove provides sane interface for internal proofs;
  3943 omits the infamous "standard" operation, so this is more appropriate
  3944 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3945 
  3946 * Pure: improved error reporting of simprocs;
  3947 
  3948 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3949 up simprocs;
  3950 
  3951 
  3952 *** Document preparation ***
  3953 
  3954 * uses \par instead of \\ for line breaks in theory text. This may
  3955 shift some page breaks in large documents. To get the old behaviour
  3956 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3957 
  3958 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3959 other packages
  3960 
  3961 * \<euro> now needs package babel/greek instead of marvosym (which
  3962 broke \Rightarrow)
  3963 
  3964 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3965 textcomp package)
  3966 
  3967 
  3968 
  3969 New in Isabelle2002 (March 2002)
  3970 --------------------------------
  3971 
  3972 *** Document preparation ***
  3973 
  3974 * greatly simplified document preparation setup, including more
  3975 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3976 instructive isatool mkdir; users should basically be able to get
  3977 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3978 users may run a separate document processing stage manually like this:
  3979 "isatool usedir -D output HOL Test && isatool document Test/output";
  3980 
  3981 * theory dependency graph may now be incorporated into documents;
  3982 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3983 with \includegraphics of LaTeX;
  3984 
  3985 * proper spacing of consecutive markup elements, especially text
  3986 blocks after section headings;
  3987 
  3988 * support bold style (for single symbols only), input syntax is like
  3989 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3990 
  3991 * \<bullet> is now output as bold \cdot by default, which looks much
  3992 better in printed text;
  3993 
  3994 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3995 note that these symbols are currently unavailable in Proof General /
  3996 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3997 
  3998 * isatool latex no longer depends on changed TEXINPUTS, instead
  3999 isatool document copies the Isabelle style files to the target
  4000 location;
  4001 
  4002 
  4003 *** Isar ***
  4004 
  4005 * Pure/Provers: improved proof by cases and induction;
  4006   - 'case' command admits impromptu naming of parameters (such as
  4007     "case (Suc n)");
  4008   - 'induct' method divinates rule instantiation from the inductive
  4009     claim; no longer requires excessive ?P bindings for proper
  4010     instantiation of cases;
  4011   - 'induct' method properly enumerates all possibilities of set/type
  4012     rules; as a consequence facts may be also passed through *type*
  4013     rules without further ado;
  4014   - 'induct' method now derives symbolic cases from the *rulified*
  4015     rule (before it used to rulify cases stemming from the internal
  4016     atomized version); this means that the context of a non-atomic
  4017     statement becomes is included in the hypothesis, avoiding the
  4018     slightly cumbersome show "PROP ?case" form;
  4019   - 'induct' may now use elim-style induction rules without chaining
  4020     facts, using ``missing'' premises from the goal state; this allows
  4021     rules stemming from inductive sets to be applied in unstructured
  4022     scripts, while still benefitting from proper handling of non-atomic
  4023     statements; NB: major inductive premises need to be put first, all
  4024     the rest of the goal is passed through the induction;
  4025   - 'induct' proper support for mutual induction involving non-atomic
  4026     rule statements (uses the new concept of simultaneous goals, see
  4027     below);
  4028   - append all possible rule selections, but only use the first
  4029     success (no backtracking);
  4030   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4031   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4032   - added 'print_induct_rules' (covered by help item in recent Proof
  4033     General versions);
  4034   - moved induct/cases attributes to Pure, methods to Provers;
  4035   - generic method setup instantiated for FOL and HOL;
  4036 
  4037 * Pure: support multiple simultaneous goal statements, for example
  4038 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4039 meta-level mechanism, this acts as if several individual goals had
  4040 been stated separately; in particular common proof methods need to be
  4041 repeated in order to cover all claims; note that a single elimination
  4042 step is *not* sufficient to establish the two conjunctions, so this
  4043 fails:
  4044 
  4045   assume "A & B" then have A and B ..   (*".." fails*)
  4046 
  4047 better use "obtain" in situations as above; alternative refer to
  4048 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4049 
  4050 * Pure: proper integration with ``locales''; unlike the original
  4051 version by Florian Kammller, Isar locales package high-level proof
  4052 contexts rather than raw logical ones (e.g. we admit to include
  4053 attributes everywhere); operations on locales include merge and
  4054 rename; support for implicit arguments (``structures''); simultaneous
  4055 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4056 some examples;
  4057 
  4058 * Pure: the following commands have been ``localized'', supporting a
  4059 target locale specification "(in name)": 'lemma', 'theorem',
  4060 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4061 stored both within the locale and at the theory level (exported and
  4062 qualified by the locale name);
  4063 
  4064 * Pure: theory goals may now be specified in ``long'' form, with
  4065 ad-hoc contexts consisting of arbitrary locale elements. for example
  4066 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4067 definitions may be given, too); the result is a meta-level rule with
  4068 the context elements being discharged in the obvious way;
  4069 
  4070 * Pure: new proof command 'using' allows to augment currently used
  4071 facts after a goal statement ('using' is syntactically analogous to
  4072 'apply', but acts on the goal's facts only); this allows chained facts
  4073 to be separated into parts given before and after a claim, as in
  4074 ``from a and b have C using d and e <proof>'';
  4075 
  4076 * Pure: renamed "antecedent" case to "rule_context";
  4077 
  4078 * Pure: new 'judgment' command records explicit information about the
  4079 object-logic embedding (used by several tools internally); no longer
  4080 use hard-wired "Trueprop";
  4081 
  4082 * Pure: added 'corollary' command;
  4083 
  4084 * Pure: fixed 'token_translation' command;
  4085 
  4086 * Pure: removed obsolete 'exported' attribute;
  4087 
  4088 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4089 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4090 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4091 
  4092 * Pure: method 'atomize' presents local goal premises as object-level
  4093 statements (atomic meta-level propositions); setup controlled via
  4094 rewrite rules declarations of 'atomize' attribute; example
  4095 application: 'induct' method with proper rule statements in improper
  4096 proof *scripts*;
  4097 
  4098 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4099 now consider the syntactic context of assumptions, giving a better
  4100 chance to get type-inference of the arguments right (this is
  4101 especially important for locales);
  4102 
  4103 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4104 mode;
  4105 
  4106 * Pure/obtain: the formal conclusion "thesis", being marked as
  4107 ``internal'', may no longer be reference directly in the text;
  4108 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4109 situations;
  4110 
  4111 * Pure: generic 'sym' attribute which declares a rule both as pure
  4112 'elim?' and for the 'symmetric' operation;
  4113 
  4114 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4115 text; the fixed correlation with particular command syntax has been
  4116 discontinued;
  4117 
  4118 * Pure: new method 'rules' is particularly well-suited for proof
  4119 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4120 but often produces more compact proof terms with less detours;
  4121 
  4122 * Pure/Provers/classical: simplified integration with pure rule
  4123 attributes and methods; the classical "intro?/elim?/dest?"
  4124 declarations coincide with the pure ones; the "rule" method no longer
  4125 includes classically swapped intros; "intro" and "elim" methods no
  4126 longer pick rules from the context; also got rid of ML declarations
  4127 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4128 INCOMPATIBILITY;
  4129 
  4130 * Provers/classical: attribute 'swapped' produces classical inversions
  4131 of introduction rules;
  4132 
  4133 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4134 rules instead of full simplifier context; 'iff' attribute handles
  4135 conditional rules;
  4136 
  4137 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4138 
  4139 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4140 "(permissive)" option to recover old behavior;
  4141 
  4142 * HOL: 'inductive' no longer features separate (collective) attributes
  4143 for 'intros' (was found too confusing);
  4144 
  4145 * HOL: properly declared induction rules less_induct and
  4146 wf_induct_rule;
  4147 
  4148 
  4149 *** HOL ***
  4150 
  4151 * HOL: moved over to sane numeral syntax; the new policy is as
  4152 follows:
  4153 
  4154   - 0 and 1 are polymorphic constants, which are defined on any
  4155   numeric type (nat, int, real etc.);
  4156 
  4157   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4158   binary representation internally;
  4159 
  4160   - type nat has special constructor Suc, and generally prefers Suc 0
  4161   over 1::nat and Suc (Suc 0) over 2::nat;
  4162 
  4163 This change may cause significant problems of INCOMPATIBILITY; here
  4164 are some hints on converting existing sources:
  4165 
  4166   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4167   entities, so expressions involving "-" (unary or binary minus) need
  4168   to be spaced properly;
  4169 
  4170   - existing occurrences of "1" may need to be constraint "1::nat" or
  4171   even replaced by Suc 0; similar for old "2";
  4172 
  4173   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4174 
  4175   - remove all special provisions on numerals in proofs;
  4176 
  4177 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4178 representation (depends on bin_arith_simps in the default context);
  4179 
  4180 * HOL: symbolic syntax for x^2 (numeral 2);
  4181 
  4182 * HOL: the class of all HOL types is now called "type" rather than
  4183 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4184 in axclass/classes, instance/arities, and (usually rare) occurrences
  4185 in typings (of consts etc.); internally the class is called
  4186 "HOL.type", ML programs should refer to HOLogic.typeS;
  4187 
  4188 * HOL/record package improvements:
  4189   - new derived operations "fields" to build a partial record section,
  4190     "extend" to promote a fixed record to a record scheme, and
  4191     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4192     declared as simp by default;
  4193   - shared operations ("more", "fields", etc.) now need to be always
  4194     qualified) --- potential INCOMPATIBILITY;
  4195   - removed "make_scheme" operations (use "make" with "extend") --
  4196     INCOMPATIBILITY;
  4197   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4198   - provides cases/induct rules for use with corresponding Isar
  4199     methods (for concrete records, record schemes, concrete more
  4200     parts, and schematic more parts -- in that order);
  4201   - internal definitions directly based on a light-weight abstract
  4202     theory of product types over typedef rather than datatype;
  4203 
  4204 * HOL: generic code generator for generating executable ML code from
  4205 specifications; specific support for HOL constructs such as inductive
  4206 datatypes and sets, as well as recursive functions; can be invoked
  4207 via 'generate_code' theory section;
  4208 
  4209 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4210 
  4211 * HOL: consolidated and renamed several theories.  In particular:
  4212         Ord.thy has been absorbed into HOL.thy
  4213         String.thy has been absorbed into List.thy
  4214 
  4215 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4216 (beware of argument permutation!);
  4217 
  4218 * HOL: linorder_less_split superseded by linorder_cases;
  4219 
  4220 * HOL/List: "nodups" renamed to "distinct";
  4221 
  4222 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4223 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4224   - Ex_def has changed, now need to use some_eq_ex
  4225 
  4226 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4227 in this (rare) case use:
  4228 
  4229   delSWrapper "split_all_tac"
  4230   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4231 
  4232 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4233 MAY FAIL;
  4234 
  4235 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4236 Isabelle's type classes, ^ on functions and relations has too general
  4237 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4238 necessary to attach explicit type constraints;
  4239 
  4240 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4241 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4242 renamed accordingly (eg "compI" -> "rel_compI").
  4243 
  4244 * HOL: syntax translations now work properly with numerals and records
  4245 expressions;
  4246 
  4247 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4248 of "lam" -- INCOMPATIBILITY;
  4249 
  4250 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4251 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4252 renamed "Product_Type.unit";
  4253 
  4254 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4255 
  4256 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4257 the "cases" method);
  4258 
  4259 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4260 Florian Kammller);
  4261 
  4262 * HOL/IMP: updated and converted to new-style theory format; several
  4263 parts turned into readable document, with proper Isar proof texts and
  4264 some explanations (by Gerwin Klein);
  4265 
  4266 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4267 
  4268 * HOL-Hyperreal is now a logic image;
  4269 
  4270 
  4271 *** HOLCF ***
  4272 
  4273 * Isar: consts/constdefs supports mixfix syntax for continuous
  4274 operations;
  4275 
  4276 * Isar: domain package adapted to new-style theory format, e.g. see
  4277 HOLCF/ex/Dnat.thy;
  4278 
  4279 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4280 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4281 lift.induct_tac, always use UU instead of Undef;
  4282 
  4283 * HOLCF/IMP: updated and converted to new-style theory;
  4284 
  4285 
  4286 *** ZF ***
  4287 
  4288 * Isar: proper integration of logic-specific tools and packages,
  4289 including theory commands '(co)inductive', '(co)datatype',
  4290 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4291 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4292 
  4293 * theory Main no longer includes AC; for the Axiom of Choice, base
  4294 your theory on Main_ZFC;
  4295 
  4296 * the integer library now covers quotients and remainders, with many
  4297 laws relating division to addition, multiplication, etc.;
  4298 
  4299 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4300 typeless version of the formalism;
  4301 
  4302 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4303 format;
  4304 
  4305 * ZF/Induct: new directory for examples of inductive definitions,
  4306 including theory Multiset for multiset orderings; converted to
  4307 new-style theory format;
  4308 
  4309 * ZF: many new theorems about lists, ordinals, etc.;
  4310 
  4311 
  4312 *** General ***
  4313 
  4314 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4315 variable proof controls level of detail: 0 = no proofs (only oracle
  4316 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4317 also ref manual for further ML interfaces;
  4318 
  4319 * Pure/axclass: removed obsolete ML interface
  4320 goal_subclass/goal_arity;
  4321 
  4322 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4323 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4324 separate tokens, so expressions involving minus need to be spaced
  4325 properly;
  4326 
  4327 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4328 rather than "infixl" or "infixr";
  4329 
  4330 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4331 sort constraint specifications in type inference; e.g. "x::_::foo"
  4332 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4333 type variable);
  4334 
  4335 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4336 control output of nested => (types); the default behavior is
  4337 "type_brackets";
  4338 
  4339 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4340 tokens into AST constants;
  4341 
  4342 * Pure/syntax: prefer later declarations of translations and print
  4343 translation functions; potential INCOMPATIBILITY: need to reverse
  4344 multiple declarations for same syntax element constant;
  4345 
  4346 * Pure/show_hyps reset by default (in accordance to existing Isar
  4347 practice);
  4348 
  4349 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4350 addSafter;
  4351 
  4352 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4353 as well;
  4354 
  4355 * system: tested support for MacOS X; should be able to get Isabelle +
  4356 Proof General to work in a plain Terminal after installing Poly/ML
  4357 (e.g. from the Isabelle distribution area) and GNU bash alone
  4358 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4359 support requires further installations, e.g. from
  4360 http://fink.sourceforge.net/);
  4361 
  4362 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4363 
  4364 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4365 of 40 MB), cf. ML_OPTIONS;
  4366 
  4367 * system: Proof General keywords specification is now part of the
  4368 Isabelle distribution (see etc/isar-keywords.el);
  4369 
  4370 * system: support for persistent Proof General sessions (refrain from
  4371 outdating all loaded theories on startup); user may create writable
  4372 logic images like this: ``isabelle -q HOL Test'';
  4373 
  4374 * system: smart selection of Isabelle process versus Isabelle
  4375 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4376 run both "isabelle" and "Isabelle" even if file names are badly
  4377 damaged (executable inspects the case of the first letter of its own
  4378 name); added separate "isabelle-process" and "isabelle-interface";
  4379 
  4380 * system: refrain from any attempt at filtering input streams; no
  4381 longer support ``8bit'' encoding of old isabelle font, instead proper
  4382 iso-latin characters may now be used; the related isatools
  4383 "symbolinput" and "nonascii" have disappeared as well;
  4384 
  4385 * system: removed old "xterm" interface (the print modes "xterm" and
  4386 "xterm_color" are still available for direct use in a suitable
  4387 terminal);
  4388 
  4389 
  4390 
  4391 New in Isabelle99-2 (February 2001)
  4392 -----------------------------------
  4393 
  4394 *** Overview of INCOMPATIBILITIES ***
  4395 
  4396 * HOL: please note that theories in the Library and elsewhere often use the
  4397 new-style (Isar) format; to refer to their theorems in an ML script you must
  4398 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4399 
  4400 * HOL: inductive package no longer splits induction rule aggressively,
  4401 but only as far as specified by the introductions given; the old
  4402 format may be recovered via ML function complete_split_rule or attribute
  4403 'split_rule (complete)';
  4404 
  4405 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4406 gfp_Tarski to gfp_unfold;
  4407 
  4408 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4409 
  4410 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4411 relation); infix "^^" has been renamed "``"; infix "``" has been
  4412 renamed "`"; "univalent" has been renamed "single_valued";
  4413 
  4414 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4415 operation;
  4416 
  4417 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4418 
  4419 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4420 
  4421 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4422 consequence, it is no longer monotonic wrt. the local goal context
  4423 (which is now passed through the inductive cases);
  4424 
  4425 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4426 \<gg> to \<ggreater>;
  4427 
  4428 
  4429 *** Document preparation ***
  4430 
  4431 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4432 available: are "it" for near math-mode best-style output, "sl" for
  4433 slanted text style, and "tt" for plain type-writer; if no
  4434 \isabellestyle command is given, output is according to slanted
  4435 type-writer);
  4436 
  4437 * support sub/super scripts (for single symbols only), input syntax is
  4438 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4439 
  4440 * some more standard symbols; see Appendix A of the system manual for
  4441 the complete list of symbols defined in isabellesym.sty;
  4442 
  4443 * improved isabelle style files; more abstract symbol implementation
  4444 (should now use \isamath{...} and \isatext{...} in custom symbol
  4445 definitions);
  4446 
  4447 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4448 state; Note that presentation of goal states does not conform to
  4449 actual human-readable proof documents.  Please do not include goal
  4450 states into document output unless you really know what you are doing!
  4451 
  4452 * proper indentation of antiquoted output with proportional LaTeX
  4453 fonts;
  4454 
  4455 * no_document ML operator temporarily disables LaTeX document
  4456 generation;
  4457 
  4458 * isatool unsymbolize tunes sources for plain ASCII communication;
  4459 
  4460 
  4461 *** Isar ***
  4462 
  4463 * Pure: Isar now suffers initial goal statements to contain unbound
  4464 schematic variables (this does not conform to actual readable proof
  4465 documents, due to unpredictable outcome and non-compositional proof
  4466 checking); users who know what they are doing may use schematic goals
  4467 for Prolog-style synthesis of proven results;
  4468 
  4469 * Pure: assumption method (an implicit finishing) now handles actual
  4470 rules as well;
  4471 
  4472 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4473 initial goal, declare "that" only as Pure intro (only for single
  4474 steps); the "that" rule assumption may now be involved in implicit
  4475 finishing, thus ".." becomes a feasible for trivial obtains;
  4476 
  4477 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4478 instance proofs may be performed by "..";
  4479 
  4480 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4481 statements as well;
  4482 
  4483 * Pure: more robust selection of calculational rules;
  4484 
  4485 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4486 rule (as well as the assumption rule);
  4487 
  4488 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4489 lemmas, using the graph browser tool;
  4490 
  4491 * Pure: predict failure of "show" in interactive mode;
  4492 
  4493 * Pure: 'thms_containing' now takes actual terms as arguments;
  4494 
  4495 * HOL: improved method 'induct' --- now handles non-atomic goals
  4496 (potential INCOMPATIBILITY); tuned error handling;
  4497 
  4498 * HOL: cases and induct rules now provide explicit hints about the
  4499 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4500 any remaining facts are inserted into the goal verbatim;
  4501 
  4502 * HOL: local contexts (aka cases) may now contain term bindings as
  4503 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4504 the result to be shown in each case;
  4505 
  4506 * HOL: added 'recdef_tc' command;
  4507 
  4508 * isatool convert assists in eliminating legacy ML scripts;
  4509 
  4510 
  4511 *** HOL ***
  4512 
  4513 * HOL/Library: a collection of generic theories to be used together
  4514 with main HOL; the theory loader path already includes this directory
  4515 by default; the following existing theories have been moved here:
  4516 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4517 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4518 
  4519 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4520 modelling and verification task performed in Isabelle/HOL +
  4521 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4522 
  4523 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4524 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4525 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4526 'domain', this makes the theory consistent with mathematical
  4527 literature;
  4528 
  4529 * HOL basics: added overloaded operations "inverse" and "divide"
  4530 (infix "/"), syntax for generic "abs" operation, generic summation
  4531 operator \<Sum>;
  4532 
  4533 * HOL/typedef: simplified package, provide more useful rules (see also
  4534 HOL/subset.thy);
  4535 
  4536 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4537 now expressed as a proper nested rule (old-style tactic scripts may
  4538 require atomize_strip_tac to cope with non-atomic premises);
  4539 
  4540 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4541 to "split_conv" (old name still available for compatibility);
  4542 
  4543 * HOL: improved concrete syntax for strings (e.g. allows translation
  4544 rules with string literals);
  4545 
  4546 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4547  and Fleuriot's mechanization of analysis, including the transcendental
  4548  functions for the reals;
  4549 
  4550 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4551 
  4552 
  4553 *** CTT ***
  4554 
  4555 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4556 "lam" is displayed as TWO lambda-symbols
  4557 
  4558 * CTT: theory Main now available, containing everything (that is, Bool
  4559 and Arith);
  4560 
  4561 
  4562 *** General ***
  4563 
  4564 * Pure: the Simplifier has been implemented properly as a derived rule
  4565 outside of the actual kernel (at last!); the overall performance
  4566 penalty in practical applications is about 50%, while reliability of
  4567 the Isabelle inference kernel has been greatly improved;
  4568 
  4569 * print modes "brackets" and "no_brackets" control output of nested =>
  4570 (types) and ==> (props); the default behaviour is "brackets";
  4571 
  4572 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4573 as assumptions as well;
  4574 
  4575 * system: support Poly/ML 4.0;
  4576 
  4577 * system: isatool install handles KDE version 1 or 2;
  4578 
  4579 
  4580 
  4581 New in Isabelle99-1 (October 2000)
  4582 ----------------------------------
  4583 
  4584 *** Overview of INCOMPATIBILITIES ***
  4585 
  4586 * HOL: simplification of natural numbers is much changed; to partly
  4587 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4588 issue the following ML commands:
  4589 
  4590   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4591   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4592 
  4593 * HOL: simplification no longer dives into case-expressions; this is
  4594 controlled by "t.weak_case_cong" for each datatype t;
  4595 
  4596 * HOL: nat_less_induct renamed to less_induct;
  4597 
  4598 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4599 fixsome to patch .thy and .ML sources automatically;
  4600 
  4601   select_equality  -> some_equality
  4602   select_eq_Ex     -> some_eq_ex
  4603   selectI2EX       -> someI2_ex
  4604   selectI2         -> someI2
  4605   selectI          -> someI
  4606   select1_equality -> some1_equality
  4607   Eps_sym_eq       -> some_sym_eq_trivial
  4608   Eps_eq           -> some_eq_trivial
  4609 
  4610 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4611 
  4612 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4613 instead);
  4614 
  4615 * HOL: the recursion equations generated by 'recdef' are now called
  4616 f.simps instead of f.rules;
  4617 
  4618 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4619 
  4620 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4621 sometimes be needed;
  4622 
  4623 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4624 
  4625 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4626 
  4627 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4628 product is now "<*>" instead of "Times"; the lexicographic product is
  4629 now "<*lex*>" instead of "**";
  4630 
  4631 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4632 of main HOL, but was unused); better use HOL's datatype package;
  4633 
  4634 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4635 the old syntax may be recovered as follows:
  4636 
  4637   syntax (symbols)
  4638     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4639       (infixl "\\<oplus>" 100)
  4640 
  4641 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4642 
  4643 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4644 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4645 internally;
  4646 
  4647 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4648 changed from A/r to A//r;
  4649 
  4650 * ZF: new treatment of arithmetic (nat & int) may break some old
  4651 proofs;
  4652 
  4653 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4654 rulify -> rule_format, elimify -> elim_format, ...);
  4655 
  4656 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4657 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4658 should have to change intro!! to intro? only); replaced "delrule" by
  4659 "rule del";
  4660 
  4661 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4662 
  4663 * Provers: strengthened force_tac by using new first_best_tac;
  4664 
  4665 * LaTeX document preparation: several changes of isabelle.sty (see
  4666 lib/texinputs);
  4667 
  4668 
  4669 *** Document preparation ***
  4670 
  4671 * formal comments (text blocks etc.) in new-style theories may now
  4672 contain antiquotations of thm/prop/term/typ/text to be presented
  4673 according to latex print mode; concrete syntax is like this:
  4674 @{term[show_types] "f(x) = a + x"};
  4675 
  4676 * isatool mkdir provides easy setup of Isabelle session directories,
  4677 including proper document sources;
  4678 
  4679 * generated LaTeX sources are now deleted after successful run
  4680 (isatool document -c); may retain a copy somewhere else via -D option
  4681 of isatool usedir;
  4682 
  4683 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4684 style files, achieving self-contained LaTeX sources and simplifying
  4685 LaTeX debugging;
  4686 
  4687 * old-style theories now produce (crude) LaTeX output as well;
  4688 
  4689 * browser info session directories are now self-contained (may be put
  4690 on WWW server seperately); improved graphs of nested sessions; removed
  4691 graph for 'all sessions';
  4692 
  4693 * several improvements in isabelle style files; \isabellestyle{it}
  4694 produces fake math mode output; \isamarkupheader is now \section by
  4695 default; see lib/texinputs/isabelle.sty etc.;
  4696 
  4697 
  4698 *** Isar ***
  4699 
  4700 * Isar/Pure: local results and corresponding term bindings are now
  4701 subject to Hindley-Milner polymorphism (similar to ML); this
  4702 accommodates incremental type-inference very nicely;
  4703 
  4704 * Isar/Pure: new derived language element 'obtain' supports
  4705 generalized existence reasoning;
  4706 
  4707 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4708 support accumulation of results, without applying any rules yet;
  4709 useful to collect intermediate results without explicit name
  4710 references, and for use with transitivity rules with more than 2
  4711 premises;
  4712 
  4713 * Isar/Pure: scalable support for case-analysis type proofs: new
  4714 'case' language element refers to local contexts symbolically, as
  4715 produced by certain proof methods; internally, case names are attached
  4716 to theorems as "tags";
  4717 
  4718 * Isar/Pure: theory command 'hide' removes declarations from
  4719 class/type/const name spaces;
  4720 
  4721 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4722 indicate potential overloading;
  4723 
  4724 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4725 
  4726 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4727 "{a,b,c}" instead of {a,b,c};
  4728 
  4729 * Isar/Pure now provides its own version of intro/elim/dest
  4730 attributes; useful for building new logics, but beware of confusion
  4731 with the version in Provers/classical;
  4732 
  4733 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4734 case name 'antecedent';
  4735 
  4736 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4737 to the current context is now done automatically);
  4738 
  4739 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4740 for definining proof methods in ML;
  4741 
  4742 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4743 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4744 most cases, one should have to change intro!! to intro? only);
  4745 replaced "delrule" by "rule del";
  4746 
  4747 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4748 'symmetric' attribute (the latter supercedes [RS sym]);
  4749 
  4750 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4751 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4752 well (including splits);
  4753 
  4754 * Isar/Provers: Simplifier and Classical methods now support all kind
  4755 of modifiers used in the past, including 'cong', 'iff', etc.
  4756 
  4757 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4758 of Simplifier and Classical reasoner);
  4759 
  4760 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4761 now support named cases; major packages (inductive, datatype, primrec,
  4762 recdef) support case names and properly name parameters;
  4763 
  4764 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4765 monotonicity conditions are extracted to be proven at end of
  4766 calculations;
  4767 
  4768 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4769 method anyway;
  4770 
  4771 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4772 split_if split_if_asm; datatype package provides theorems foo.splits =
  4773 foo.split foo.split_asm for each datatype;
  4774 
  4775 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4776 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4777 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4778 use "(cases (simplified))" method in proper proof texts);
  4779 
  4780 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4781 
  4782 * Isar: names of theorems etc. may be natural numbers as well;
  4783 
  4784 * Isar: 'pr' command: optional arguments for goals_limit and
  4785 ProofContext.prems_limit; no longer prints theory contexts, but only
  4786 proof states;
  4787 
  4788 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4789 additional print modes to be specified; e.g. "pr(latex)" will print
  4790 proof state according to the Isabelle LaTeX style;
  4791 
  4792 * Isar: improved support for emulating tactic scripts, including proof
  4793 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4794 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4795 (for HOL datatypes);
  4796 
  4797 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4798 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4799 'proof method scripts' have to be in depth-first order;
  4800 
  4801 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4802 
  4803 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4804 should instead use individual commands for printing items
  4805 (print_commands, print_methods etc.);
  4806 
  4807 * Isar: added 'nothing' --- the empty list of theorems;
  4808 
  4809 
  4810 *** HOL ***
  4811 
  4812 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4813 corresponding virtual machine and a specification of its bytecode
  4814 verifier and a lightweight bytecode verifier, including proofs of
  4815 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4816 Cornelia Pusch (see also the homepage of project Bali at
  4817 http://isabelle.in.tum.de/Bali/);
  4818 
  4819 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4820 Clemens Ballarin;
  4821 
  4822 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4823 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4824 Rasmussen;
  4825 
  4826 * HOL/Lattice: fundamental concepts of lattice theory and order
  4827 structures, including duals, properties of bounds versus algebraic
  4828 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4829 Theorem for complete lattices etc.; may also serve as a demonstration
  4830 for abstract algebraic reasoning using axiomatic type classes, and
  4831 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4832 
  4833 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4834 von Oheimb;
  4835 
  4836 * HOL/IMPP: extension of IMP with local variables and mutually
  4837 recursive procedures, by David von Oheimb;
  4838 
  4839 * HOL/Lambda: converted into new-style theory and document;
  4840 
  4841 * HOL/ex/Multiquote: example of multiple nested quotations and
  4842 anti-quotations -- basically a generalized version of de-Bruijn
  4843 representation; very useful in avoiding lifting of operations;
  4844 
  4845 * HOL/record: added general record equality rule to simpset; fixed
  4846 select-update simplification procedure to handle extended records as
  4847 well; admit "r" as field name;
  4848 
  4849 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4850 other numeric types and also as the identity of groups, rings, etc.;
  4851 
  4852 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4853 Types nat and int belong to this axclass;
  4854 
  4855 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4856    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4857    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4858   two terms #m*u and #n*u are replaced by #(m+n)*u
  4859     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4860   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4861     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4862 
  4863 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4864 powerful prover for predicate logic but knows nothing of clasets; see
  4865 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4866 
  4867 * HOL: new version of "case_tac" subsumes both boolean case split and
  4868 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4869 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4870 
  4871 * HOL: simplification no longer dives into case-expressions: only the
  4872 selector expression is simplified, but not the remaining arms; to
  4873 enable full simplification of case-expressions for datatype t, you may
  4874 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4875 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4876 
  4877 * HOL/recdef: the recursion equations generated by 'recdef' for
  4878 function 'f' are now called f.simps instead of f.rules; if all
  4879 termination conditions are proved automatically, these simplification
  4880 rules are added to the simpset, as in primrec; rules may be named
  4881 individually as well, resulting in a separate list of theorems for
  4882 each equation;
  4883 
  4884 * HOL/While is a new theory that provides a while-combinator. It
  4885 permits the definition of tail-recursive functions without the
  4886 provision of a termination measure. The latter is necessary once the
  4887 invariant proof rule for while is applied.
  4888 
  4889 * HOL: new (overloaded) notation for the set of elements below/above
  4890 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4891 
  4892 * HOL: theorems impI, allI, ballI bound as "strip";
  4893 
  4894 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4895 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4896 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4897 
  4898 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4899 
  4900 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4901 main HOL, but was unused);
  4902 
  4903 * HOL: fewer consts declared as global (e.g. have to refer to
  4904 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4905 
  4906 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4907 in case of overlap with user translations (e.g. judgements over
  4908 tuples); (note that the underlying logical represenation is still
  4909 bogus);
  4910 
  4911 
  4912 *** ZF ***
  4913 
  4914 * ZF: simplification automatically cancels common terms in arithmetic
  4915 expressions over nat and int;
  4916 
  4917 * ZF: new treatment of nat to minimize type-checking: all operators
  4918 coerce their operands to a natural number using the function natify,
  4919 making the algebraic laws unconditional;
  4920 
  4921 * ZF: as above, for int: operators coerce their operands to an integer
  4922 using the function intify;
  4923 
  4924 * ZF: the integer library now contains many of the usual laws for the
  4925 orderings, including $<=, and monotonicity laws for $+ and $*;
  4926 
  4927 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4928 simplification;
  4929 
  4930 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4931 to the simplifier and classical reasoner simultaneously;
  4932 
  4933 
  4934 *** General ***
  4935 
  4936 * Provers: blast_tac now handles actual object-logic rules as
  4937 assumptions; note that auto_tac uses blast_tac internally as well;
  4938 
  4939 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4940 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4941 
  4942 * Provers: delrules now handles destruct rules as well (no longer need
  4943 explicit make_elim);
  4944 
  4945 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4946   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4947 use instead the strong form,
  4948   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4949 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4950 from destruct-rules;
  4951 
  4952 * Provers: Simplifier.easy_setup provides a fast path to basic
  4953 Simplifier setup for new object-logics;
  4954 
  4955 * Pure: AST translation rules no longer require constant head on LHS;
  4956 
  4957 * Pure: improved name spaces: ambiguous output is qualified; support
  4958 for hiding of names;
  4959 
  4960 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4961 XSYMBOL_HOME; no longer need to do manual configuration in most
  4962 situations;
  4963 
  4964 * system: compression of ML heaps images may now be controlled via -c
  4965 option of isabelle and isatool usedir (currently only observed by
  4966 Poly/ML);
  4967 
  4968 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4969 useful for remote X11);
  4970 
  4971 * system: provide TAGS file for Isabelle sources;
  4972 
  4973 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4974 order;
  4975 
  4976 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4977 timing flag supersedes proof_timing and Toplevel.trace;
  4978 
  4979 * ML: new combinators |>> and |>>> for incremental transformations
  4980 with secondary results (e.g. certain theory extensions):
  4981 
  4982 * ML: PureThy.add_defs gets additional argument to indicate potential
  4983 overloading (usually false);
  4984 
  4985 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4986 results;
  4987 
  4988 
  4989 
  4990 New in Isabelle99 (October 1999)
  4991 --------------------------------
  4992 
  4993 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4994 
  4995 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4996 are no longer simplified.  (This allows the simplifier to unfold recursive
  4997 functional programs.)  To restore the old behaviour, declare
  4998 
  4999     Delcongs [if_weak_cong];
  5000 
  5001 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5002 complement;
  5003 
  5004 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5005 
  5006 * HOL/datatype: mutual_induct_tac no longer exists --
  5007   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5008 
  5009 * HOL/typedef: fixed type inference for representing set; type
  5010 arguments now have to occur explicitly on the rhs as type constraints;
  5011 
  5012 * ZF: The con_defs part of an inductive definition may no longer refer
  5013 to constants declared in the same theory;
  5014 
  5015 * HOL, ZF: the function mk_cases, generated by the inductive
  5016 definition package, has lost an argument.  To simplify its result, it
  5017 uses the default simpset instead of a supplied list of theorems.
  5018 
  5019 * HOL/List: the constructors of type list are now Nil and Cons;
  5020 
  5021 * Simplifier: the type of the infix ML functions
  5022         setSSolver addSSolver setSolver addSolver
  5023 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5024 for packaging solvers. A solver is created via
  5025         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5026 where the string argument is only a comment.
  5027 
  5028 
  5029 *** Proof tools ***
  5030 
  5031 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5032 decision procedure for linear arithmetic. Currently it is used for
  5033 types `nat', `int', and `real' in HOL (see below); it can, should and
  5034 will be instantiated for other types and logics as well.
  5035 
  5036 * The simplifier now accepts rewrite rules with flexible heads, eg
  5037      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5038   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5039   matching.
  5040 
  5041 
  5042 *** General ***
  5043 
  5044 * New Isabelle/Isar subsystem provides an alternative to traditional
  5045 tactical theorem proving; together with the ProofGeneral/isar user
  5046 interface it offers an interactive environment for developing human
  5047 readable proof documents (Isar == Intelligible semi-automated
  5048 reasoning); for further information see isatool doc isar-ref,
  5049 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5050 
  5051 * improved and simplified presentation of theories: better HTML markup
  5052 (including colors), graph views in several sizes; isatool usedir now
  5053 provides a proper interface for user theories (via -P option); actual
  5054 document preparation based on (PDF)LaTeX is available as well (for
  5055 new-style theories only); see isatool doc system for more information;
  5056 
  5057 * native support for Proof General, both for classic Isabelle and
  5058 Isabelle/Isar;
  5059 
  5060 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5061 using the graph browser tool;
  5062 
  5063 * Isabelle manuals now also available as PDF;
  5064 
  5065 * theory loader rewritten from scratch (may not be fully
  5066 bug-compatible); old loadpath variable has been replaced by show_path,
  5067 add_path, del_path, reset_path functions; new operations such as
  5068 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5069 isatool doc ref);
  5070 
  5071 * improved isatool install: option -k creates KDE application icon,
  5072 option -p DIR installs standalone binaries;
  5073 
  5074 * added ML_PLATFORM setting (useful for cross-platform installations);
  5075 more robust handling of platform specific ML images for SML/NJ;
  5076 
  5077 * the settings environment is now statically scoped, i.e. it is never
  5078 created again in sub-processes invoked from isabelle, isatool, or
  5079 Isabelle;
  5080 
  5081 * path element specification '~~' refers to '$ISABELLE_HOME';
  5082 
  5083 * in locales, the "assumes" and "defines" parts may be omitted if
  5084 empty;
  5085 
  5086 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5087 long arrows);
  5088 
  5089 * new print_mode "HTML";
  5090 
  5091 * new flag show_tags controls display of tags of theorems (which are
  5092 basically just comments that may be attached by some tools);
  5093 
  5094 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5095 mode and goal output format:
  5096 
  5097 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5098 244c244
  5099 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5100 ---
  5101 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5102 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5103 181c181
  5104 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5105 ---
  5106 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5107 
  5108 * function bind_thms stores lists of theorems (cf. bind_thm);
  5109 
  5110 * new shorthand tactics ftac, eatac, datac, fatac;
  5111 
  5112 * qed (and friends) now accept "" as result name; in that case the
  5113 theorem is not stored, but proper checks and presentation of the
  5114 result still apply;
  5115 
  5116 * theorem database now also indexes constants "Trueprop", "all",
  5117 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5118 
  5119 
  5120 *** HOL ***
  5121 
  5122 ** HOL arithmetic **
  5123 
  5124 * There are now decision procedures for linear arithmetic over nat and
  5125 int:
  5126 
  5127 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5128 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5129 are treated as atomic; subformulae not involving type `nat' or `int'
  5130 are ignored; quantified subformulae are ignored unless they are
  5131 positive universal or negative existential. The tactic has to be
  5132 invoked by hand and can be a little bit slow. In particular, the
  5133 running time is exponential in the number of occurrences of `min' and
  5134 `max', and `-' on `nat'.
  5135 
  5136 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5137 (negated) (in)equalities among the premises and the conclusion into
  5138 account (i.e. no compound formulae) and does not know about `min' and
  5139 `max', and `-' on `nat'. It is fast and is used automatically by the
  5140 simplifier.
  5141 
  5142 NB: At the moment, these decision procedures do not cope with mixed
  5143 nat/int formulae where the two parts interact, such as `m < n ==>
  5144 int(m) < int(n)'.
  5145 
  5146 * HOL/Numeral provides a generic theory of numerals (encoded
  5147 efficiently as bit strings); setup for types nat/int/real is in place;
  5148 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5149 int, existing theories and proof scripts may require a few additional
  5150 type constraints;
  5151 
  5152 * integer division and remainder can now be performed on constant
  5153 arguments;
  5154 
  5155 * many properties of integer multiplication, division and remainder
  5156 are now available;
  5157 
  5158 * An interface to the Stanford Validity Checker (SVC) is available through the
  5159 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5160 are proved automatically.  SVC must be installed separately, and its results
  5161 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5162 invocation of the underlying oracle).  For SVC see
  5163   http://verify.stanford.edu/SVC
  5164 
  5165 * IsaMakefile: the HOL-Real target now builds an actual image;
  5166 
  5167 
  5168 ** HOL misc **
  5169 
  5170 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5171 (in Isabelle/Isar) -- by Gertrud Bauer;
  5172 
  5173 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5174 analysis for assembly languages with subtypes;
  5175 
  5176 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5177 -- avoids syntactic ambiguities and treats state, transition, and
  5178 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5179 changed syntax and (many) tactics;
  5180 
  5181 * HOL/inductive: Now also handles more general introduction rules such
  5182   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5183   theorems are now maintained within the theory (maintained via the
  5184   "mono" attribute);
  5185 
  5186 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5187   (using function types) such as
  5188 
  5189   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5190 
  5191 * HOL/record: record_simproc (part of the default simpset) takes care
  5192 of selectors applied to updated records; record_split_tac is no longer
  5193 part of the default claset; update_defs may now be removed from the
  5194 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5195 
  5196   claset_ref () := claset() addSWrapper record_split_wrapper;
  5197   Delsimprocs [record_simproc]
  5198 
  5199 * HOL/typedef: fixed type inference for representing set; type
  5200 arguments now have to occur explicitly on the rhs as type constraints;
  5201 
  5202 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5203 names rather than an ML expression;
  5204 
  5205 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5206 supplied later.  Program schemes can be defined, such as
  5207     "While B C s = (if B s then While B C (C s) else s)"
  5208 where the well-founded relation can be chosen after B and C have been given.
  5209 
  5210 * HOL/List: the constructors of type list are now Nil and Cons;
  5211 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5212 course, ML tools referring to List.list.op # etc. have to be adapted;
  5213 
  5214 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5215 disabled by default; run isabelle with option -m HOL to get back to
  5216 the original Gordon/HOL-style output;
  5217 
  5218 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5219 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5220 
  5221 * HOL basic syntax simplified (more orthogonal): all variants of
  5222 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5223 Eps operator is provided as well: "SOME x. P[x]";
  5224 
  5225 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5226 
  5227 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5228 thus available for user theories;
  5229 
  5230 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5231 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5232 time;
  5233 
  5234 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5235 several times and then mp;
  5236 
  5237 
  5238 *** LK ***
  5239 
  5240 * the notation <<...>> is now available as a notation for sequences of
  5241 formulas;
  5242 
  5243 * the simplifier is now installed
  5244 
  5245 * the axiom system has been generalized (thanks to Soren Heilmann)
  5246 
  5247 * the classical reasoner now has a default rule database
  5248 
  5249 
  5250 *** ZF ***
  5251 
  5252 * new primrec section allows primitive recursive functions to be given
  5253 directly (as in HOL) over datatypes and the natural numbers;
  5254 
  5255 * new tactics induct_tac and exhaust_tac for induction (or case
  5256 analysis) over datatypes and the natural numbers;
  5257 
  5258 * the datatype declaration of type T now defines the recursor T_rec;
  5259 
  5260 * simplification automatically does freeness reasoning for datatype
  5261 constructors;
  5262 
  5263 * automatic type-inference, with AddTCs command to insert new
  5264 type-checking rules;
  5265 
  5266 * datatype introduction rules are now added as Safe Introduction rules
  5267 to the claset;
  5268 
  5269 * the syntax "if P then x else y" is now available in addition to
  5270 if(P,x,y);
  5271 
  5272 
  5273 *** Internal programming interfaces ***
  5274 
  5275 * tuned simplifier trace output; new flag debug_simp;
  5276 
  5277 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5278 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5279 
  5280 * AxClass.axclass_tac lost the theory argument;
  5281 
  5282 * tuned current_goals_markers semantics: begin / end goal avoids
  5283 printing empty lines;
  5284 
  5285 * removed prs and prs_fn hook, which was broken because it did not
  5286 include \n in its semantics, forcing writeln to add one
  5287 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5288 string -> unit if you really want to output text without newline;
  5289 
  5290 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5291 plain output, interface builders may have to enable 'isabelle_font'
  5292 mode to get Isabelle font glyphs as before;
  5293 
  5294 * refined token_translation interface; INCOMPATIBILITY: output length
  5295 now of type real instead of int;
  5296 
  5297 * theory loader actions may be traced via new ThyInfo.add_hook
  5298 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5299 your own database of information attached to *whole* theories -- as
  5300 opposed to intra-theory data slots offered via TheoryDataFun;
  5301 
  5302 * proper handling of dangling sort hypotheses (at last!);
  5303 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5304 extra sort hypotheses that can be witnessed from the type signature;
  5305 the force_strip_shyps flag is gone, any remaining shyps are simply
  5306 left in the theorem (with a warning issued by strip_shyps_warning);
  5307 
  5308 
  5309 
  5310 New in Isabelle98-1 (October 1998)
  5311 ----------------------------------
  5312 
  5313 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5314 
  5315 * several changes of automated proof tools;
  5316 
  5317 * HOL: major changes to the inductive and datatype packages, including
  5318 some minor incompatibilities of theory syntax;
  5319 
  5320 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5321 called `inj_on';
  5322 
  5323 * HOL: removed duplicate thms in Arith:
  5324   less_imp_add_less  should be replaced by  trans_less_add1
  5325   le_imp_add_le      should be replaced by  trans_le_add1
  5326 
  5327 * HOL: unary minus is now overloaded (new type constraints may be
  5328 required);
  5329 
  5330 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5331 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5332 now taken as an integer constant.
  5333 
  5334 * Pure: ML function 'theory_of' renamed to 'theory';
  5335 
  5336 
  5337 *** Proof tools ***
  5338 
  5339 * Simplifier:
  5340   1. Asm_full_simp_tac is now more aggressive.
  5341      1. It will sometimes reorient premises if that increases their power to
  5342         simplify.
  5343      2. It does no longer proceed strictly from left to right but may also
  5344         rotate premises to achieve further simplification.
  5345      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5346      old Asm_full_simp_tac in that it does not rotate premises.
  5347   2. The simplifier now knows a little bit about nat-arithmetic.
  5348 
  5349 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5350 allows for selected deletion of wrappers, by introduction of names for
  5351 wrapper functionals.  This implies that addbefore, addSbefore,
  5352 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5353 and that adding two tactics with the same name overwrites the first
  5354 one (emitting a warning).
  5355   type wrapper = (int -> tactic) -> (int -> tactic)
  5356   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5357   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5358   delWrapper, delSWrapper: claset *  string            -> claset
  5359   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5360 
  5361 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5362 semantics; addbefore now affects only the unsafe part of step_tac
  5363 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5364 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5365 by Force_tac;
  5366 
  5367 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5368 compWrapper; added safe wrapper (and access functions for it);
  5369 
  5370 * HOL/split_all_tac is now much faster and fails if there is nothing
  5371 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5372 and the names of the automatically generated variables have changed.
  5373 split_all_tac has moved within claset() from unsafe wrappers to safe
  5374 wrappers, which means that !!-bound variables are split much more
  5375 aggressively, and safe_tac and clarify_tac now split such variables.
  5376 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5377 Note: the same holds for record_split_tac, which does the job of
  5378 split_all_tac for record fields.
  5379 
  5380 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5381 permanently to the default simpset using Addsplits just like
  5382 Addsimps. They can be removed via Delsplits just like
  5383 Delsimps. Lower-case versions are also available.
  5384 
  5385 * HOL/Simplifier: The rule split_if is now part of the default
  5386 simpset. This means that the simplifier will eliminate all occurrences
  5387 of if-then-else in the conclusion of a goal. To prevent this, you can
  5388 either remove split_if completely from the default simpset by
  5389 `Delsplits [split_if]' or remove it in a specific call of the
  5390 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5391 other case splitting rules to/from the default simpset: every datatype
  5392 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5393 t is the name of the datatype).
  5394 
  5395 * Classical reasoner / Simplifier combination: new force_tac (and
  5396 derivatives Force_tac, force) combines rewriting and classical
  5397 reasoning (and whatever other tools) similarly to auto_tac, but is
  5398 aimed to solve the given subgoal completely.
  5399 
  5400 
  5401 *** General ***
  5402 
  5403 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5404 and `goalw': the theory is no longer needed as an explicit argument -
  5405 the current theory context is used; assumptions are no longer returned
  5406 at the ML-level unless one of them starts with ==> or !!; it is
  5407 recommended to convert to these new commands using isatool fixgoal
  5408 (backup your sources first!);
  5409 
  5410 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5411 the current theory context, and 'theory' to lookup stored theories;
  5412 
  5413 * new theory section 'locale' for declaring constants, assumptions and
  5414 definitions that have local scope;
  5415 
  5416 * new theory section 'nonterminals' for purely syntactic types;
  5417 
  5418 * new theory section 'setup' for generic ML setup functions
  5419 (e.g. package initialization);
  5420 
  5421 * the distribution now includes Isabelle icons: see
  5422 lib/logo/isabelle-{small,tiny}.xpm;
  5423 
  5424 * isatool install - install binaries with absolute references to
  5425 ISABELLE_HOME/bin;
  5426 
  5427 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5428 
  5429 * print mode 'emacs' reserved for Isamode;
  5430 
  5431 * support multiple print (ast) translations per constant name;
  5432 
  5433 * theorems involving oracles are now printed with a suffixed [!];
  5434 
  5435 
  5436 *** HOL ***
  5437 
  5438 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5439 
  5440 * HOL/inductive package reorganized and improved: now supports mutual
  5441 definitions such as
  5442 
  5443   inductive EVEN ODD
  5444     intrs
  5445       null "0 : EVEN"
  5446       oddI "n : EVEN ==> Suc n : ODD"
  5447       evenI "n : ODD ==> Suc n : EVEN"
  5448 
  5449 new theorem list "elims" contains an elimination rule for each of the
  5450 recursive sets; inductive definitions now handle disjunctive premises
  5451 correctly (also ZF);
  5452 
  5453 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5454 "mutual_induct" no longer exists - the induction rule is always
  5455 contained in "induct";
  5456 
  5457 
  5458 * HOL/datatype package re-implemented and greatly improved: now
  5459 supports mutually recursive datatypes such as
  5460 
  5461   datatype
  5462     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5463             | SUM ('a aexp) ('a aexp)
  5464             | DIFF ('a aexp) ('a aexp)
  5465             | NUM 'a
  5466   and
  5467     'a bexp = LESS ('a aexp) ('a aexp)
  5468             | AND ('a bexp) ('a bexp)
  5469             | OR ('a bexp) ('a bexp)
  5470 
  5471 as well as indirectly recursive datatypes such as
  5472 
  5473   datatype
  5474     ('a, 'b) term = Var 'a
  5475                   | App 'b ((('a, 'b) term) list)
  5476 
  5477 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5478 induction on mutually / indirectly recursive datatypes.
  5479 
  5480 Primrec equations are now stored in theory and can be accessed via
  5481 <function_name>.simps.
  5482 
  5483 INCOMPATIBILITIES:
  5484 
  5485   - Theories using datatypes must now have theory Datatype as an
  5486     ancestor.
  5487   - The specific <typename>.induct_tac no longer exists - use the
  5488     generic induct_tac instead.
  5489   - natE has been renamed to nat.exhaust - use exhaust_tac
  5490     instead of res_inst_tac ... natE. Note that the variable
  5491     names in nat.exhaust differ from the names in natE, this
  5492     may cause some "fragile" proofs to fail.
  5493   - The theorems split_<typename>_case and split_<typename>_case_asm
  5494     have been renamed to <typename>.split and <typename>.split_asm.
  5495   - Since default sorts of type variables are now handled correctly,
  5496     some datatype definitions may have to be annotated with explicit
  5497     sort constraints.
  5498   - Primrec definitions no longer require function name and type
  5499     of recursive argument.
  5500 
  5501 Consider using isatool fixdatatype to adapt your theories and proof
  5502 scripts to the new package (backup your sources first!).
  5503 
  5504 
  5505 * HOL/record package: considerably improved implementation; now
  5506 includes concrete syntax for record types, terms, updates; theorems
  5507 for surjective pairing and splitting !!-bound record variables; proof
  5508 support is as follows:
  5509 
  5510   1) standard conversions (selectors or updates applied to record
  5511 constructor terms) are part of the standard simpset;
  5512 
  5513   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5514 made part of standard simpset and claset via addIffs;
  5515 
  5516   3) a tactic for record field splitting (record_split_tac) is part of
  5517 the standard claset (addSWrapper);
  5518 
  5519 To get a better idea about these rules you may retrieve them via
  5520 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5521 the name of your record type.
  5522 
  5523 The split tactic 3) conceptually simplifies by the following rule:
  5524 
  5525   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5526 
  5527 Thus any record variable that is bound by meta-all will automatically
  5528 blow up into some record constructor term, consequently the
  5529 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5530 solve record problems automatically.
  5531 
  5532 
  5533 * reorganized the main HOL image: HOL/Integ and String loaded by
  5534 default; theory Main includes everything;
  5535 
  5536 * automatic simplification of integer sums and comparisons, using cancellation;
  5537 
  5538 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5539 
  5540 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5541 
  5542 * many new identities for unions, intersections, set difference, etc.;
  5543 
  5544 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5545 called split_if, split_split, split_sum_case and split_nat_case (to go
  5546 with add/delsplits);
  5547 
  5548 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5549 (?x::unit) = (); this is made part of the default simpset, which COULD
  5550 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5551 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5552 unit_abs_eta_conv is added in order to counter the effect of
  5553 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5554 %u.f();
  5555 
  5556 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5557 makes more sense);
  5558 
  5559 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5560   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5561   disjointness reasoning but breaking a few old proofs.
  5562 
  5563 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5564 to 'converse' from 'inverse' (for compatibility with ZF and some
  5565 literature);
  5566 
  5567 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5568 the well-founded relation;
  5569 
  5570 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5571     Compl A.  The "Compl" syntax remains available as input syntax for this
  5572     release ONLY.
  5573 
  5574 * HOL/Update: new theory of function updates:
  5575     f(a:=b) == %x. if x=a then b else f x
  5576 may also be iterated as in f(a:=b,c:=d,...);
  5577 
  5578 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5579 
  5580 * HOL/List:
  5581   - new function list_update written xs[i:=v] that updates the i-th
  5582     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5583   - new function `upt' written [i..j(] which generates the list
  5584     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5585     bound write [i..j], which is a shorthand for [i..j+1(].
  5586   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5587 
  5588 * HOL/Arith:
  5589   - removed 'pred' (predecessor) function;
  5590   - generalized some theorems about n-1;
  5591   - many new laws about "div" and "mod";
  5592   - new laws about greatest common divisors (see theory ex/Primes);
  5593 
  5594 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5595 instead of "inverse";
  5596 
  5597 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5598   of the multiset ordering;
  5599 
  5600 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5601   (not included by default);
  5602 
  5603 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5604 
  5605 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5606   programs, i.e. different program variables may have different types.
  5607 
  5608 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5609   [previously, this check worked only if the rewrite rule was unconditional]
  5610   Now rew can involve either definitions or equalities (either == or =).
  5611 
  5612 
  5613 *** ZF ***
  5614 
  5615 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5616   only the theorems proved on ZF.ML;
  5617 
  5618 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5619   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5620   disjointness reasoning but breaking a few old proofs.
  5621 
  5622 * ZF/Update: new theory of function updates
  5623     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5624   may also be iterated as in f(a:=b,c:=d,...);
  5625 
  5626 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5627 
  5628 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5629   [previously, this check worked only if the rewrite rule was unconditional]
  5630   Now rew can involve either definitions or equalities (either == or =).
  5631 
  5632 * case_tac provided for compatibility with HOL
  5633     (like the old excluded_middle_tac, but with subgoals swapped)
  5634 
  5635 
  5636 *** Internal programming interfaces ***
  5637 
  5638 * Pure: several new basic modules made available for general use, see
  5639 also src/Pure/README;
  5640 
  5641 * improved the theory data mechanism to support encapsulation (data
  5642 kind name replaced by private Object.kind, acting as authorization
  5643 key); new type-safe user interface via functor TheoryDataFun; generic
  5644 print_data function becomes basically useless;
  5645 
  5646 * removed global_names compatibility flag -- all theory declarations
  5647 are qualified by default;
  5648 
  5649 * module Pure/Syntax now offers quote / antiquote translation
  5650 functions (useful for Hoare logic etc. with implicit dependencies);
  5651 see HOL/ex/Antiquote for an example use;
  5652 
  5653 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5654 cterm -> thm;
  5655 
  5656 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5657 subgoal;
  5658 
  5659 * Display.print_goals function moved to Locale.print_goals;
  5660 
  5661 * standard print function for goals supports current_goals_markers
  5662 variable for marking begin of proof, end of proof, start of goal; the
  5663 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5664 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5665 for example;
  5666 
  5667 
  5668 
  5669 New in Isabelle98 (January 1998)
  5670 --------------------------------
  5671 
  5672 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5673 
  5674 * changed lexical syntax of terms / types: dots made part of long
  5675 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5676 
  5677 * simpset (and claset) reference variable replaced by functions
  5678 simpset / simpset_ref;
  5679 
  5680 * no longer supports theory aliases (via merge) and non-trivial
  5681 implicit merge of thms' signatures;
  5682 
  5683 * most internal names of constants changed due to qualified names;
  5684 
  5685 * changed Pure/Sequence interface (see Pure/seq.ML);
  5686 
  5687 
  5688 *** General Changes ***
  5689 
  5690 * hierachically structured name spaces (for consts, types, axms, thms
  5691 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5692 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5693 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5694 long_names for fully qualified output names; NOTE: ML programs
  5695 (special tactics, packages etc.) referring to internal names may have
  5696 to be adapted to cope with fully qualified names; in case of severe
  5697 backward campatibility problems try setting 'global_names' at compile
  5698 time to have enrything declared within a flat name space; one may also
  5699 fine tune name declarations in theories via the 'global' and 'local'
  5700 section;
  5701 
  5702 * reimplemented the implicit simpset and claset using the new anytype
  5703 data filed in signatures; references simpset:simpset ref etc. are
  5704 replaced by functions simpset:unit->simpset and
  5705 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5706 to patch your ML files accordingly;
  5707 
  5708 * HTML output now includes theory graph data for display with Java
  5709 applet or isatool browser; data generated automatically via isatool
  5710 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5711 
  5712 * defs may now be conditional; improved rewrite_goals_tac to handle
  5713 conditional equations;
  5714 
  5715 * defs now admits additional type arguments, using TYPE('a) syntax;
  5716 
  5717 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5718 creates a new theory node; implicit merge of thms' signatures is
  5719 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5720 transfer:theory->thm->thm in (rare) cases;
  5721 
  5722 * improved handling of draft signatures / theories; draft thms (and
  5723 ctyps, cterms) are automatically promoted to real ones;
  5724 
  5725 * slightly changed interfaces for oracles: admit many per theory, named
  5726 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5727 
  5728 * print_goals: optional output of const types (set show_consts and
  5729 show_types);
  5730 
  5731 * improved output of warnings (###) and errors (***);
  5732 
  5733 * subgoal_tac displays a warning if the new subgoal has type variables;
  5734 
  5735 * removed old README and Makefiles;
  5736 
  5737 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5738 
  5739 * removed obsolete init_pps and init_database;
  5740 
  5741 * deleted the obsolete tactical STATE, which was declared by
  5742     fun STATE tacfun st = tacfun st st;
  5743 
  5744 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5745 (which abbreviates $HOME);
  5746 
  5747 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5748 use isatool fixseq to adapt your ML programs (this works for fully
  5749 qualified references to the Sequence structure only!);
  5750 
  5751 * use_thy no longer requires writable current directory; it always
  5752 reloads .ML *and* .thy file, if either one is out of date;
  5753 
  5754 
  5755 *** Classical Reasoner ***
  5756 
  5757 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5758 tactics that use classical reasoning to simplify a subgoal without
  5759 splitting it into several subgoals;
  5760 
  5761 * Safe_tac: like safe_tac but uses the default claset;
  5762 
  5763 
  5764 *** Simplifier ***
  5765 
  5766 * added simplification meta rules:
  5767     (asm_)(full_)simplify: simpset -> thm -> thm;
  5768 
  5769 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5770 logics (again);
  5771 
  5772 * added prems argument to simplification procedures;
  5773 
  5774 * HOL, FOL, ZF: added infix function `addsplits':
  5775   instead of `<simpset> setloop (split_tac <thms>)'
  5776   you can simply write `<simpset> addsplits <thms>'
  5777 
  5778 
  5779 *** Syntax ***
  5780 
  5781 * TYPE('a) syntax for type reflection terms;
  5782 
  5783 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5784 
  5785 * pretty printer: changed order of mixfix annotation preference (again!);
  5786 
  5787 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5788 
  5789 
  5790 *** HOL ***
  5791 
  5792 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5793   with `addloop' of the simplifier to faciliate case splitting in premises.
  5794 
  5795 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5796 
  5797 * HOL/Auth: new protocol proofs including some for the Internet
  5798   protocol TLS;
  5799 
  5800 * HOL/Map: new theory of `maps' a la VDM;
  5801 
  5802 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5803 cancelling out common nat summands from =, <, <= (in)equalities, or
  5804 differences; simplification procedures nat_cancel_factor for
  5805 cancelling common factor from =, <, <= (in)equalities over natural
  5806 sums; nat_cancel contains both kinds of procedures, it is installed by
  5807 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5808 
  5809 * HOL/simplifier: terms of the form
  5810   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5811   are rewritten to
  5812   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5813   and those of the form
  5814   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5815   are rewritten to
  5816   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5817 
  5818 * HOL/datatype
  5819   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5820 
  5821   P(t_case f1 ... fn x) =
  5822      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5823         ...
  5824        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5825      )
  5826 
  5827   and a theorem `split_t_case_asm' of the form
  5828 
  5829   P(t_case f1 ... fn x) =
  5830     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5831         ...
  5832        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5833      )
  5834   which can be added to a simpset via `addsplits'. The existing theorems
  5835   expand_list_case and expand_option_case have been renamed to
  5836   split_list_case and split_option_case.
  5837 
  5838 * HOL/Arithmetic:
  5839   - `pred n' is automatically converted to `n-1'.
  5840     Users are strongly encouraged not to use `pred' any longer,
  5841     because it will disappear altogether at some point.
  5842   - Users are strongly encouraged to write "0 < n" rather than
  5843     "n ~= 0". Theorems and proof tools have been modified towards this
  5844     `standard'.
  5845 
  5846 * HOL/Lists:
  5847   the function "set_of_list" has been renamed "set" (and its theorems too);
  5848   the function "nth" now takes its arguments in the reverse order and
  5849   has acquired the infix notation "!" as in "xs!n".
  5850 
  5851 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5852 
  5853 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5854   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5855 
  5856 * HOL/record: extensible records with schematic structural subtyping
  5857 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5858 still lacks various theorems and concrete record syntax;
  5859 
  5860 
  5861 *** HOLCF ***
  5862 
  5863 * removed "axioms" and "generated by" sections;
  5864 
  5865 * replaced "ops" section by extended "consts" section, which is capable of
  5866   handling the continuous function space "->" directly;
  5867 
  5868 * domain package:
  5869   . proves theorems immediately and stores them in the theory,
  5870   . creates hierachical name space,
  5871   . now uses normal mixfix annotations (instead of cinfix...),
  5872   . minor changes to some names and values (for consistency),
  5873   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5874   . separator between mutual domain defs: changed "," to "and",
  5875   . improved handling of sort constraints;  now they have to
  5876     appear on the left-hand side of the equations only;
  5877 
  5878 * fixed LAM <x,y,zs>.b syntax;
  5879 
  5880 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5881 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5882 
  5883 
  5884 *** FOL and ZF ***
  5885 
  5886 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5887   with `addloop' of the simplifier to faciliate case splitting in premises.
  5888 
  5889 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5890 in HOL, they strip ALL and --> from proved theorems;
  5891 
  5892 
  5893 
  5894 New in Isabelle94-8 (May 1997)
  5895 ------------------------------
  5896 
  5897 *** General Changes ***
  5898 
  5899 * new utilities to build / run / maintain Isabelle etc. (in parts
  5900 still somewhat experimental); old Makefiles etc. still functional;
  5901 
  5902 * new 'Isabelle System Manual';
  5903 
  5904 * INSTALL text, together with ./configure and ./build scripts;
  5905 
  5906 * reimplemented type inference for greater efficiency, better error
  5907 messages and clean internal interface;
  5908 
  5909 * prlim command for dealing with lots of subgoals (an easier way of
  5910 setting goals_limit);
  5911 
  5912 
  5913 *** Syntax ***
  5914 
  5915 * supports alternative (named) syntax tables (parser and pretty
  5916 printer); internal interface is provided by add_modesyntax(_i);
  5917 
  5918 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5919 be used in conjunction with the Isabelle symbol font; uses the
  5920 "symbols" syntax table;
  5921 
  5922 * added token_translation interface (may translate name tokens in
  5923 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5924 the current print_mode); IMPORTANT: user print translation functions
  5925 are responsible for marking newly introduced bounds
  5926 (Syntax.mark_boundT);
  5927 
  5928 * token translations for modes "xterm" and "xterm_color" that display
  5929 names in bold, underline etc. or colors (which requires a color
  5930 version of xterm);
  5931 
  5932 * infixes may now be declared with names independent of their syntax;
  5933 
  5934 * added typed_print_translation (like print_translation, but may
  5935 access type of constant);
  5936 
  5937 
  5938 *** Classical Reasoner ***
  5939 
  5940 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5941 some limitations.  Blast_tac...
  5942   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5943   + ignores elimination rules that don't have the correct format
  5944         (the conclusion MUST be a formula variable)
  5945   + ignores types, which can make HOL proofs fail
  5946   + rules must not require higher-order unification, e.g. apply_type in ZF
  5947     [message "Function Var's argument not a bound variable" relates to this]
  5948   + its proof strategy is more general but can actually be slower
  5949 
  5950 * substitution with equality assumptions no longer permutes other
  5951 assumptions;
  5952 
  5953 * minor changes in semantics of addafter (now called addaltern); renamed
  5954 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5955 (and access functions for it);
  5956 
  5957 * improved combination of classical reasoner and simplifier:
  5958   + functions for handling clasimpsets
  5959   + improvement of addss: now the simplifier is called _after_ the
  5960     safe steps.
  5961   + safe variant of addss called addSss: uses safe simplifications
  5962     _during_ the safe steps. It is more complete as it allows multiple
  5963     instantiations of unknowns (e.g. with slow_tac).
  5964 
  5965 *** Simplifier ***
  5966 
  5967 * added interface for simplification procedures (functions that
  5968 produce *proven* rewrite rules on the fly, depending on current
  5969 redex);
  5970 
  5971 * ordering on terms as parameter (used for ordered rewriting);
  5972 
  5973 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5974 
  5975 * the solver is now split into a safe and an unsafe part.
  5976 This should be invisible for the normal user, except that the
  5977 functions setsolver and addsolver have been renamed to setSolver and
  5978 addSolver; added safe_asm_full_simp_tac;
  5979 
  5980 
  5981 *** HOL ***
  5982 
  5983 * a generic induction tactic `induct_tac' which works for all datatypes and
  5984 also for type `nat';
  5985 
  5986 * a generic case distinction tactic `exhaust_tac' which works for all
  5987 datatypes and also for type `nat';
  5988 
  5989 * each datatype comes with a function `size';
  5990 
  5991 * patterns in case expressions allow tuple patterns as arguments to
  5992 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5993 
  5994 * primrec now also works with type nat;
  5995 
  5996 * recdef: a new declaration form, allows general recursive functions to be
  5997 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5998 
  5999 * the constant for negation has been renamed from "not" to "Not" to
  6000 harmonize with FOL, ZF, LK, etc.;
  6001 
  6002 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6003 infinite lists;
  6004 
  6005 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6006 
  6007 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6008 problems in commutative rings, using axiomatic type classes for + and *;
  6009 
  6010 * more examples in HOL/MiniML and HOL/Auth;
  6011 
  6012 * more default rewrite rules for quantifiers, union/intersection;
  6013 
  6014 * a new constant `arbitrary == @x.False';
  6015 
  6016 * HOLCF/IOA replaces old HOL/IOA;
  6017 
  6018 * HOLCF changes: derived all rules and arities
  6019   + axiomatic type classes instead of classes
  6020   + typedef instead of faking type definitions
  6021   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6022   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6023   + eliminated the types void, one, tr
  6024   + use unit lift and bool lift (with translations) instead of one and tr
  6025   + eliminated blift from Lift3.thy (use Def instead of blift)
  6026   all eliminated rules are derived as theorems --> no visible changes ;
  6027 
  6028 
  6029 *** ZF ***
  6030 
  6031 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6032 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6033 as ZF_cs addSIs [equalityI];
  6034 
  6035 
  6036 
  6037 New in Isabelle94-7 (November 96)
  6038 ---------------------------------
  6039 
  6040 * allowing negative levels (as offsets) in prlev and choplev;
  6041 
  6042 * super-linear speedup for large simplifications;
  6043 
  6044 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6045 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6046 FAIL); can suppress it using the command Delsimps (ex_simps @
  6047 all_simps); De Morgan laws are also now included, by default;
  6048 
  6049 * improved printing of ==>  :  ~:
  6050 
  6051 * new object-logic "Sequents" adds linear logic, while replacing LK
  6052 and Modal (thanks to Sara Kalvala);
  6053 
  6054 * HOL/Auth: correctness proofs for authentication protocols;
  6055 
  6056 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6057 examples on HOL/Auth);
  6058 
  6059 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6060 the rewriter and classical reasoner simultaneously;
  6061 
  6062 * function uresult no longer returns theorems in "standard" format;
  6063 regain previous version by: val uresult = standard o uresult;
  6064 
  6065 
  6066 
  6067 New in Isabelle94-6
  6068 -------------------
  6069 
  6070 * oracles -- these establish an interface between Isabelle and trusted
  6071 external reasoners, which may deliver results as theorems;
  6072 
  6073 * proof objects (in particular record all uses of oracles);
  6074 
  6075 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6076 
  6077 * "constdefs" section in theory files;
  6078 
  6079 * "primrec" section (HOL) no longer requires names;
  6080 
  6081 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6082 
  6083 
  6084 
  6085 New in Isabelle94-5
  6086 -------------------
  6087 
  6088 * reduced space requirements;
  6089 
  6090 * automatic HTML generation from theories;
  6091 
  6092 * theory files no longer require "..." (quotes) around most types;
  6093 
  6094 * new examples, including two proofs of the Church-Rosser theorem;
  6095 
  6096 * non-curried (1994) version of HOL is no longer distributed;
  6097 
  6098 
  6099 
  6100 New in Isabelle94-4
  6101 -------------------
  6102 
  6103 * greatly reduced space requirements;
  6104 
  6105 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6106 
  6107 * searchable theorem database (see the section "Retrieving theorems" on
  6108 page 8 of the Reference Manual);
  6109 
  6110 * new examples, including Grabczewski's monumental case study of the
  6111 Axiom of Choice;
  6112 
  6113 * The previous version of HOL renamed to Old_HOL;
  6114 
  6115 * The new version of HOL (previously called CHOL) uses a curried syntax
  6116 for functions.  Application looks like f a b instead of f(a,b);
  6117 
  6118 * Mutually recursive inductive definitions finally work in HOL;
  6119 
  6120 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6121 translates to the operator "split";
  6122 
  6123 
  6124 
  6125 New in Isabelle94-3
  6126 -------------------
  6127 
  6128 * new infix operator, addss, allowing the classical reasoner to
  6129 perform simplification at each step of its search.  Example:
  6130         fast_tac (cs addss ss)
  6131 
  6132 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6133 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6134 look like (a,b) instead of <a,b>;
  6135 
  6136 * PLEASE NOTE: CHOL will eventually replace HOL!
  6137 
  6138 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6139 It translates to the operator "split".  A new theory of integers is available;
  6140 
  6141 * In ZF, integer numerals now denote two's-complement binary integers.
  6142 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6143 
  6144 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6145 of the Axiom of Choice;
  6146 
  6147 
  6148 
  6149 New in Isabelle94-2
  6150 -------------------
  6151 
  6152 * Significantly faster resolution;
  6153 
  6154 * the different sections in a .thy file can now be mixed and repeated
  6155 freely;
  6156 
  6157 * Database of theorems for FOL, HOL and ZF.  New
  6158 commands including qed, qed_goal and bind_thm store theorems in the database.
  6159 
  6160 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6161 a given theory (thms_of), or find out what theory a theorem was proved in
  6162 (theory_of_thm);
  6163 
  6164 * Bugs fixed in the inductive definition and datatype packages;
  6165 
  6166 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6167 and HOL_dup_cs obsolete;
  6168 
  6169 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6170 have been removed;
  6171 
  6172 * Simpler definition of function space in ZF;
  6173 
  6174 * new results about cardinal and ordinal arithmetic in ZF;
  6175 
  6176 * 'subtype' facility in HOL for introducing new types as subsets of existing
  6177 types;
  6178 
  6179 :mode=text:wrap=hard:maxLineLen=72: