NEWS
author wenzelm
Sun Mar 15 16:59:17 2009 +0100 (2009-03-15)
changeset 30539 c96c72709a20
parent 30538 a77b7995062a
parent 30530 03c120763ea8
child 30547 4c2514625873
permissions -rw-r--r--
merged
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * The main reference manuals (isar-ref, implementation, system) have
    10 been updated and extended.  Formally checked references as hyperlinks
    11 are now available in uniform manner.
    12 
    13 * Simplified main Isabelle executables, with less surprises on
    14 case-insensitive file-systems (such as Mac OS).
    15 
    16   - The main Isabelle tool wrapper is now called "isabelle" instead of
    17     "isatool."
    18 
    19   - The former "isabelle" alias for "isabelle-process" has been
    20     removed (should rarely occur to regular users).
    21 
    22   - The former "isabelle-interface" and its alias "Isabelle" have been
    23     removed (interfaces are now regular Isabelle tools).
    24 
    25 Within scripts and make files, the Isabelle environment variables
    26 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    27 respectively.  (The latter are still available as legacy feature.)
    28 
    29 The old isabelle-interface wrapper could react in confusing ways if
    30 the interface was uninstalled or changed otherwise.  Individual
    31 interface tool configuration is now more explicit, see also the
    32 Isabelle system manual.  In particular, Proof General is now available
    33 via "isabelle emacs".
    34 
    35 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    36 purge installed copies of Isabelle executables and re-run "isabelle
    37 install -p ...", or use symlinks.
    38 
    39 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    40 old ~/isabelle, which was slightly non-standard and apt cause
    41 surprises on case-insensitive file-systems.
    42 
    43 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    44 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    45 care is required when using older releases of Isabelle.  Note that
    46 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    47 Isabelle distribution.
    48 
    49 * Proofs of fully specified statements are run in parallel on
    50 multi-core systems.  A speedup factor of 2-3 can be expected on a
    51 regular 4-core machine, if the initial heap space is made reasonably
    52 large (cf. Poly/ML option -H).  [Poly/ML 5.2.1 or later]
    53 
    54 * Generalized Isar history, with support for linear undo, direct state
    55 addressing etc.
    56 
    57 * Recovered hiding of consts, which was accidentally broken in
    58 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
    59 makes c inaccessible; consider using ``hide (open) const c'' instead.
    60 
    61 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
    62 interface instead.
    63 
    64 * There is a new syntactic category "float_const" for signed decimal
    65 fractions (e.g. 123.45 or -123.45).
    66 
    67 * New prover for coherent logic (see src/Tools/coherent.ML).
    68 
    69 
    70 *** Pure ***
    71 
    72 * Class declaration: sc. "base sort" must not be given in import list
    73 any longer but is inferred from the specification.  Particularly in HOL,
    74 write
    75 
    76     class foo = ...     instead of      class foo = type + ...
    77 
    78 * Module moves in repository:
    79     src/Pure/Tools/value.ML ~> src/Tools/
    80     src/Pure/Tools/quickcheck.ML ~> src/Tools/
    81 
    82 * Slightly more coherent Pure syntax, with updated documentation in
    83 isar-ref manual.  Removed locales meta_term_syntax and
    84 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
    85 INCOMPATIBILITY in rare situations.
    86 
    87 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
    88 hypotheses.  Sorts required in the course of reasoning need to be
    89 covered by the constraints in the initial statement, completed by the
    90 type instance information of the background theory.  Non-trivial sort
    91 hypotheses, which rarely occur in practice, may be specified via
    92 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
    93 
    94   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
    95 
    96 The result contains an implicit sort hypotheses as before --
    97 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
    98 normalization.
    99 
   100 * Changed defaults for unify configuration options:
   101 
   102   unify_trace_bound = 50 (formerly 25)
   103   unify_search_bound = 60 (formerly 30)
   104 
   105 * Different bookkeeping for code equations (INCOMPATIBILITY):
   106 
   107   a) On theory merge, the last set of code equations for a particular
   108      constant is taken (in accordance with the policy applied by other
   109      parts of the code generator framework).
   110 
   111   b) Code equations stemming from explicit declarations (e.g. code
   112      attribute) gain priority over default code equations stemming
   113      from definition, primrec, fun etc.
   114 
   115 * Global versions of theorems stemming from classes do not carry a
   116 parameter prefix any longer.  INCOMPATIBILITY.
   117 
   118 * Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   119 In existing theorem specifications replace the includes element by the
   120 respective context elements of the included locale, omitting those
   121 that are already present in the theorem specification.  Multiple
   122 assume elements of a locale should be replaced by a single one
   123 involving the locale predicate.  In the proof body, declarations (most
   124 notably theorems) may be regained by interpreting the respective
   125 locales in the proof context as required (command "interpret").
   126 
   127 If using "includes" in replacement of a target solely because the
   128 parameter types in the theorem are not as general as in the target,
   129 consider declaring a new locale with additional type constraints on
   130 the parameters (context element "constrains").
   131 
   132 * Dropped "locale (open)".  INCOMPATIBILITY.
   133 
   134 * Interpretation commands no longer attempt to simplify goal.
   135 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   136 methods intro_locales and unfold_locales to clarify.
   137 
   138 * Interpretation commands no longer accept interpretation attributes.
   139 INCOMPATBILITY.
   140 
   141 * Complete re-implementation of locales.  INCOMPATIBILITY.  The most
   142 important changes are listed below.  See documentation (forthcoming)
   143 and tutorial (also forthcoming) for details.
   144 
   145 - In locale expressions, instantiation replaces renaming.  Parameters
   146 must be declared in a for clause.  To aid compatibility with previous
   147 parameter inheritance, in locale declarations, parameters that are not
   148 'touched' (instantiation position "_" or omitted) are implicitly added
   149 with their syntax at the beginning of the for clause.
   150 
   151 - Syntax from abbreviations and definitions in locales is available in
   152 locale expressions and context elements.  The latter is particularly
   153 useful in locale declarations.
   154 
   155 - More flexible mechanisms to qualify names generated by locale
   156 expressions.  Qualifiers (prefixes) may be specified in locale
   157 expressions.  Available are normal qualifiers (syntax "name:") and
   158 strict qualifiers (syntax "name!:").  The latter must occur in name
   159 references and are useful to avoid accidental hiding of names, the
   160 former are optional.  Qualifiers derived from the parameter names of a
   161 locale are no longer generated.
   162 
   163 - "sublocale l < e" replaces "interpretation l < e".  The
   164 instantiation clause in "interpretation" and "interpret" (square
   165 brackets) is no longer available.  Use locale expressions.
   166 
   167 - When converting proof scripts, be sure to replace qualifiers in
   168 "interpretation" and "interpret" by strict qualifiers.  Qualifiers in
   169 locale expressions range over a single locale instance only.
   170 
   171 * Command 'instance': attached definitions no longer accepted.
   172 INCOMPATIBILITY, use proper 'instantiation' target.
   173 
   174 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   175 
   176 * The 'axiomatization' command now only works within a global theory
   177 context.  INCOMPATIBILITY.
   178 
   179 * New find_theorems criterion "solves" matching theorems that directly
   180 solve the current goal. Try "find_theorems solves".
   181 
   182 * Added an auto solve option, which can be enabled through the
   183 ProofGeneral Isabelle settings menu (disabled by default).
   184  
   185 When enabled, find_theorems solves is called whenever a new lemma is
   186 stated. Any theorems that could solve the lemma directly are listed
   187 underneath the goal.
   188 
   189 * New command 'find_consts' searches for constants based on type and
   190 name patterns, e.g.
   191 
   192     find_consts "_ => bool"
   193 
   194 By default, matching is against subtypes, but it may be restricted to
   195 the whole type. Searching by name is possible. Multiple queries are
   196 conjunctive and queries may be negated by prefixing them with a
   197 hyphen:
   198 
   199     find_consts strict: "_ => bool" name: "Int" -"int => int"
   200 
   201 * New command 'local_setup' is similar to 'setup', but operates on a
   202 local theory context.
   203 
   204 
   205 *** Document preparation ***
   206 
   207 * Antiquotation @{lemma} now imitates a regular terminal proof,
   208 demanding keyword 'by' and supporting the full method expression
   209 syntax just like the Isar command 'by'.
   210 
   211 
   212 *** HOL ***
   213 
   214 * Theory Library/Diagonalize.thy provides constructive version of
   215 Cantor's first diagonalization argument.
   216 
   217 * New predicate "strict_mono" classifies strict functions on partial orders.
   218 With strict functions on linear orders, reasoning about (in)equalities is
   219 facilitated by theorems "strict_mono_eq", "strict_mono_less_eq" and "strict_mono_less".
   220 
   221 * Some set operations are now proper qualified constants with authentic syntax.
   222 INCOMPATIBILITY:
   223 
   224     op Int ~>   Set.Int
   225     op Un ~>    Set.Un
   226     INTER ~>    Set.INTER
   227     UNION ~>    Set.UNION
   228     Inter ~>    Set.Inter
   229     Union ~>    Set.Union
   230     {} ~>       Set.empty
   231     UNIV ~>     Set.UNIV
   232 
   233 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in theory
   234 Set.
   235 
   236 * Auxiliary class "itself" has disappeared -- classes without any parameter
   237 are treated as expected by the 'class' command.
   238 
   239 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   240 
   241 * Common decision procedures (Cooper, MIR, Ferrack, Approximation, Dense_Linear_Order)
   242 now in directory HOL/Decision_Procs.
   243 
   244 * Theory HOL/Decisioin_Procs/Approximation.thy provides the new proof method
   245 "approximation".  It proves formulas on real values by using interval arithmetic.
   246 In the formulas are also the transcendental functions sin, cos, tan, atan, ln,
   247 exp and the constant pi are allowed. For examples see
   248 HOL/Descision_Procs/ex/Approximation_Ex.thy.
   249 
   250 * Theory "Reflection" now resides in HOL/Library.
   251 
   252 * Entry point to Word library now simply named "Word".  INCOMPATIBILITY.
   253 
   254 * Made source layout more coherent with logical distribution
   255 structure:
   256 
   257     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   258     src/HOL/Library/Code_Message.thy ~> src/HOL/
   259     src/HOL/Library/GCD.thy ~> src/HOL/
   260     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   261     src/HOL/Library/Parity.thy ~> src/HOL/
   262     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   263     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   264     src/HOL/Real/Lubs.thy ~> src/HOL/
   265     src/HOL/Real/PReal.thy ~> src/HOL/
   266     src/HOL/Real/Rational.thy ~> src/HOL/
   267     src/HOL/Real/RComplete.thy ~> src/HOL/
   268     src/HOL/Real/RealDef.thy ~> src/HOL/
   269     src/HOL/Real/RealPow.thy ~> src/HOL/
   270     src/HOL/Real/Real.thy ~> src/HOL/
   271     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   272     src/HOL/Complex/Complex.thy ~> src/HOL/
   273     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   274     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   275     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   276     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   277     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   278     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   279     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   280     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   281     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   282     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   283     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   284     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   285     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   286     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   287     src/HOL/Real/Float ~> src/HOL/Library/
   288     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   289     src/HOL/Real/RealVector.thy ~> src/HOL/
   290 
   291     src/HOL/arith_data.ML ~> src/HOL/Tools
   292     src/HOL/hologic.ML ~> src/HOL/Tools
   293     src/HOL/simpdata.ML ~> src/HOL/Tools
   294     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   295     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   296     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   297     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   298     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   299     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   300     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   301 
   302     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   303     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   304     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   305     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   306     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   307     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   308 
   309 * If methods "eval" and "evaluation" encounter a structured proof state
   310 with !!/==>, only the conclusion is evaluated to True (if possible),
   311 avoiding strange error messages.
   312 
   313 * Simplifier: simproc for let expressions now unfolds if bound variable
   314 occurs at most once in let expression body.  INCOMPATIBILITY.
   315 
   316 * New classes "top" and "bot" with corresponding operations "top" and "bot"
   317 in theory Orderings;  instantiation of class "complete_lattice" requires
   318 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   319 
   320 * Changed definition lemma "less_fun_def" in order to provide an instance
   321 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   322 
   323 * Unified theorem tables for both code code generators.  Thus
   324 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   325 
   326 * Constants "undefined" and "default" replace "arbitrary".  Usually
   327 "undefined" is the right choice to replace "arbitrary", though logically
   328 there is no difference.  INCOMPATIBILITY.
   329 
   330 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   331 Posix processes.  Avoids potentially expensive forking of the ML
   332 process.  New thread-based implementation also works on non-Unix
   333 platforms (Cygwin).  Provers are no longer hardwired, but defined
   334 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   335 commands are covered in the isar-ref manual.
   336 
   337 * Wrapper scripts for remote SystemOnTPTP service allows to use
   338 sledgehammer without local ATP installation (Vampire etc.). Other
   339 provers may be included via suitable ML wrappers, see also
   340 src/HOL/ATP_Linkup.thy.
   341 
   342 * Normalization by evaluation now allows non-leftlinear equations.
   343 Declare with attribute [code nbe].
   344 
   345 * Command "value" now integrates different evaluation
   346 mechanisms.  The result of the first successful evaluation mechanism
   347 is printed.  In square brackets a particular named evaluation
   348 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   349 further src/HOL/ex/Eval_Examples.thy.
   350 
   351 * New method "sizechange" to automate termination proofs using (a
   352 modification of) the size-change principle. Requires SAT solver. See
   353 src/HOL/ex/Termination.thy for examples.
   354 
   355 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   356 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   357 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   358 
   359 * HOL/Orderings: added class "preorder" as superclass of "order".
   360 INCOMPATIBILITY: Instantiation proofs for order, linorder
   361 etc. slightly changed.  Some theorems named order_class.* now named
   362 preorder_class.*.
   363 
   364 * HOL/Relation:
   365 Renamed "refl" to "refl_on", "reflexive" to "refl, "diag" to "Id_on".
   366 
   367 * HOL/Finite_Set: added a new fold combinator of type
   368   ('a => 'b => 'b) => 'b => 'a set => 'b
   369 Occasionally this is more convenient than the old fold combinator which is
   370 now defined in terms of the new one and renamed to fold_image.
   371 
   372 * HOL/Ring_and_Field and HOL/OrderedGroup: The lemmas "group_simps" and
   373 "ring_simps" have been replaced by "algebra_simps" (which can be extended with
   374 further lemmas!). At the moment both still exist but the former will disappear
   375 at some point.
   376 
   377 * HOL/Power: Lemma power_Suc is now declared as a simp rule in class
   378 recpower.  Type-specific simp rules for various recpower types have
   379 been removed.  INCOMPATIBILITY.  Rename old lemmas as follows:
   380 
   381 rat_power_0    -> power_0
   382 rat_power_Suc  -> power_Suc
   383 realpow_0      -> power_0
   384 realpow_Suc    -> power_Suc
   385 complexpow_0   -> power_0
   386 complexpow_Suc -> power_Suc
   387 power_poly_0   -> power_0
   388 power_poly_Suc -> power_Suc
   389 
   390 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   391 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   392 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   393 of lemmas from Divides has been generalized from nat to class
   394 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   395 renames resulting from duplicate elimination:
   396 
   397     dvd_def_mod ~>          dvd_eq_mod_eq_0
   398     zero_dvd_iff ~>         dvd_0_left_iff
   399     dvd_0 ~>                dvd_0_right
   400     DIVISION_BY_ZERO_DIV ~> div_by_0
   401     DIVISION_BY_ZERO_MOD ~> mod_by_0
   402     mult_div ~>             div_mult_self2_is_id
   403     mult_mod ~>             mod_mult_self2_is_0
   404 
   405 * HOL/IntDiv: removed many lemmas that are instances of class-based
   406 generalizations (from Divides and Ring_and_Field).
   407 INCOMPATIBILITY. Rename old lemmas as follows:
   408 
   409 dvd_diff               -> nat_dvd_diff
   410 dvd_zminus_iff         -> dvd_minus_iff
   411 mod_add1_eq            -> mod_add_eq
   412 mod_mult1_eq           -> mod_mult_right_eq
   413 mod_mult1_eq'          -> mod_mult_left_eq
   414 mod_mult_distrib_mod   -> mod_mult_eq
   415 nat_mod_add_left_eq    -> mod_add_left_eq
   416 nat_mod_add_right_eq   -> mod_add_right_eq
   417 nat_mod_div_trivial    -> mod_div_trivial
   418 nat_mod_mod_trivial    -> mod_mod_trivial
   419 zdiv_zadd_self1        -> div_add_self1
   420 zdiv_zadd_self2        -> div_add_self2
   421 zdiv_zmult_self1       -> div_mult_self2_is_id
   422 zdiv_zmult_self2       -> div_mult_self1_is_id
   423 zdvd_triv_left         -> dvd_triv_left
   424 zdvd_triv_right        -> dvd_triv_right
   425 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   426 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   427 zmod_zadd_left_eq      -> mod_add_left_eq
   428 zmod_zadd_right_eq     -> mod_add_right_eq
   429 zmod_zadd_self1        -> mod_add_self1
   430 zmod_zadd_self2        -> mod_add_self2
   431 zmod_zadd1_eq          -> mod_add_eq
   432 zmod_zdiff1_eq         -> mod_diff_eq
   433 zmod_zdvd_zmod         -> mod_mod_cancel
   434 zmod_zmod_cancel       -> mod_mod_cancel
   435 zmod_zmult_self1       -> mod_mult_self2_is_0
   436 zmod_zmult_self2       -> mod_mult_self1_is_0
   437 zmod_1                 -> mod_by_1
   438 zdiv_1                 -> div_by_1
   439 zdvd_abs1              -> abs_dvd_iff
   440 zdvd_abs2              -> dvd_abs_iff
   441 zdvd_refl              -> dvd_refl
   442 zdvd_trans             -> dvd_trans
   443 zdvd_zadd              -> dvd_add
   444 zdvd_zdiff             -> dvd_diff
   445 zdvd_zminus_iff        -> dvd_minus_iff
   446 zdvd_zminus2_iff       -> minus_dvd_iff
   447 zdvd_zmultD            -> dvd_mult_right
   448 zdvd_zmultD2           -> dvd_mult_left
   449 zdvd_zmult_mono        -> mult_dvd_mono
   450 zdvd_0_right           -> dvd_0_right
   451 zdvd_0_left            -> dvd_0_left_iff
   452 zdvd_1_left            -> one_dvd
   453 zminus_dvd_iff         -> minus_dvd_iff
   454 
   455 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   456 zlcm (for int); carried together from various gcd/lcm developements in
   457 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   458 corresponding theorems renamed accordingly.  INCOMPATIBILITY.  To
   459 recover tupled syntax, use syntax declarations like:
   460 
   461     hide (open) const gcd
   462     abbreviation gcd where
   463       "gcd == (%(a, b). GCD.gcd a b)"
   464     notation (output)
   465       GCD.gcd ("gcd '(_, _')")
   466 
   467 (analogously for lcm, zgcd, zlcm).
   468 
   469 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   470 
   471 * The real numbers offer decimal input syntax: 12.34 is translated into
   472   1234/10^2. This translation is not reversed upon output.
   473 
   474 * New ML antiquotation @{code}: takes constant as argument, generates
   475 corresponding code in background and inserts name of the corresponding
   476 resulting ML value/function/datatype constructor binding in place.
   477 All occurrences of @{code} with a single ML block are generated
   478 simultaneously.  Provides a generic and safe interface for
   479 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   480 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   481 application.  In future you ought refrain from ad-hoc compiling
   482 generated SML code on the ML toplevel.  Note that (for technical
   483 reasons) @{code} cannot refer to constants for which user-defined
   484 serializations are set.  Refer to the corresponding ML counterpart
   485 directly in that cases.
   486 
   487 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   488 Complex_Main.thy remain as they are.
   489 
   490 * New image HOL-Plain provides a minimal HOL with the most important
   491 tools available (inductive, datatype, primrec, ...).  By convention
   492 the corresponding theory Plain should be ancestor of every further
   493 (library) theory.  Some library theories now have ancestor Plain
   494 (instead of Main), thus theory Main occasionally has to be imported
   495 explicitly.
   496 
   497 * The metis method now fails in the usual manner, rather than raising
   498 an exception, if it determines that it cannot prove the theorem.
   499 
   500 * The metis method no longer fails because the theorem is too trivial
   501 (contains the empty clause).
   502 
   503 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   504 as the structured Isar versions "cases" and "induct", cf. the
   505 corresponding "cases" and "induct" attributes.  Mutual induction rules
   506 are now presented as a list of individual projections
   507 (e.g. foo_bar.inducts for types foo and bar); the old format with
   508 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   509 rare situations a different rule is selected --- notably nested tuple
   510 elimination instead of former prod.exhaust: use explicit (case_tac t
   511 rule: prod.exhaust) here.
   512 
   513 * Attributes "cases", "induct", "coinduct" support "del" option.
   514 
   515 * Removed fact "case_split_thm", which duplicates "case_split".
   516 
   517 * Command 'rep_datatype': instead of theorem names the command now
   518 takes a list of terms denoting the constructors of the type to be
   519 represented as datatype.  The characteristic theorems have to be
   520 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   521 have disappeared in favour of existing ones:
   522 
   523     unit_induct                 ~> unit.induct
   524     prod_induct                 ~> prod.induct
   525     sum_induct                  ~> sum.induct
   526     Suc_Suc_eq                  ~> nat.inject
   527     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   528 
   529 * The option datatype has been moved to a new theory HOL/Option.thy.
   530 Renamed option_map to Option.map, and o2s to Option.set.
   531 
   532 * Library/Nat_Infinity: added addition, numeral syntax and more
   533 instantiations for algebraic structures.  Removed some duplicate
   534 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   535 
   536 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   537 menu.
   538 
   539 * Linear arithmetic now ignores all inequalities when
   540 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   541 
   542 
   543 *** HOL-Algebra ***
   544 
   545 * New locales for orders and lattices where the equivalence relation
   546 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   547 locales use a record structure with field eq for the equivalence.
   548 
   549 * New theory of factorial domains.
   550 
   551 * Units_l_inv and Units_r_inv are now simprules by default.
   552 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   553 and/or r_inv will now also require deletion of these lemmas.
   554 
   555 * Renamed the following theorems.  INCOMPATIBILITY.
   556 UpperD ~> Upper_memD
   557 LowerD ~> Lower_memD
   558 least_carrier ~> least_closed
   559 greatest_carrier ~> greatest_closed
   560 greatest_Lower_above ~> greatest_Lower_below
   561 one_zero ~> carrier_one_zero
   562 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   563 
   564 
   565 *** HOL-NSA ***
   566 
   567 * Created new image HOL-NSA, containing theories of nonstandard
   568 analysis which were previously part of HOL-Complex.  Entry point
   569 Hyperreal.thy remains valid, but theories formerly using
   570 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   571 
   572 
   573 *** ZF ***
   574 
   575 * Proof of Zorn's Lemma for partial orders.
   576 
   577 
   578 *** HOLCF ***
   579 
   580 * Reimplemented the simplification procedure for proving continuity
   581 subgoals.  The new simproc is extensible; users can declare additional
   582 continuity introduction rules with the attribute [cont2cont].
   583 
   584 * The continuity simproc now uses a different introduction rule for
   585 solving continuity subgoals on terms with lambda abstractions.  In
   586 some rare cases the new simproc may fail to solve subgoals that the
   587 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   588 Potential INCOMPATIBILITY.
   589 
   590 * The syntax of the fixrec package has changed.  The specification
   591 syntax now conforms in style to definition, primrec, function, etc.
   592 See HOLCF/ex/Fixrec_ex.thy for examples.  INCOMPATIBILITY.
   593 
   594 
   595 *** ML ***
   596 
   597 * High-level support for concurrent ML programming, see
   598 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   599 particularly convenient to organize independent functional
   600 computations.  The concept of "synchronized variables" provides a
   601 higher-order interface for components with shared state, avoiding the
   602 delicate details of mutexes and condition variables.  [Poly/ML 5.2.1
   603 or later]
   604 
   605 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   606 and Method.setup, as well as commands 'attribute_setup'.
   607 
   608 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   609 to 'a -> thm, while results are always tagged with an authentic oracle
   610 name.  The Isar command 'oracle' is now polymorphic, no argument type
   611 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   612 accordingly.  Note that extra performance may be gained by producing
   613 the cterm carefully, avoiding slow Thm.cterm_of.
   614 
   615 * ML bindings produced via Isar commands are stored within the Isar
   616 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   617 become thread-safe and work with undo as expected (concerning
   618 top-level bindings, not side-effects on global references).
   619 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   620 compiler at runtime; really global bindings need to be given outside a
   621 theory. [Poly/ML 5.2 or later]
   622 
   623 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   624 context. Top-level ML bindings are stored within the proof context in
   625 a purely sequential fashion, disregarding the nested proof structure.
   626 ML bindings introduced by 'ML_prf' are discarded at the end of the
   627 proof.  [Poly/ML 5.2 or later]
   628 
   629 * Generic Toplevel.add_hook interface allows to analyze the result of
   630 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   631 for theorem dependency output of transactions resulting in a new
   632 theory state.
   633 
   634 * More systematic treatment of long names, abstract name bindings, and
   635 name space operations.  Basic operations on qualified names have been
   636 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   637 Long_Name.append.  Old type bstring has been mostly replaced by
   638 abstract type binding (see structure Binding), which supports precise
   639 qualification (by packages and local theory targets), as well as
   640 proper tracking of source positions.  INCOMPATIBILITY, need to wrap
   641 old bstring values into Binding.name, or better pass through abstract
   642 bindings everywhere.  See further src/Pure/General/long_name.ML,
   643 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   644 
   645 * Simplified interface for defining document antiquotations via
   646 ThyOutput.antiquotation, ThyOutput.output, and optionally
   647 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   648 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   649 examples.
   650 
   651 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   652 LocalTheory.note etc.) now refer to the *full* internal name, not the
   653 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   654 
   655 * Rules and tactics that read instantiations (read_instantiate,
   656 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   657 context, which is required for parsing and type-checking.  Moreover,
   658 the variables are specified as plain indexnames, not string encodings
   659 thereof.  INCOMPATIBILITY.
   660 
   661 * Disposed old type and term read functions (Sign.read_def_typ,
   662 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   663 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   664 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   665 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   666 resort for legacy applications.
   667 
   668 * Antiquotations: block-structured compilation context indicated by
   669 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   670 
   671   @{let ?pat = term}                      - term abbreviation (HO matching)
   672   @{note name = fact}                     - fact abbreviation
   673   @{thm fact}                             - singleton fact (with attributes)
   674   @{thms fact}                            - general fact (with attributes)
   675   @{lemma prop by method}                 - singleton goal
   676   @{lemma prop by meth1 meth2}            - singleton goal
   677   @{lemma prop1 ... propN by method}      - general goal
   678   @{lemma prop1 ... propN by meth1 meth2} - general goal
   679   @{lemma (open) ...}                     - open derivation
   680 
   681 
   682 *** System ***
   683 
   684 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   685 Poly/ML 5.2.1 or later.
   686 
   687 * The Isabelle "emacs" tool provides a specific interface to invoke
   688 Proof General / Emacs, with more explicit failure if that is not
   689 installed (the old isabelle-interface script silently falls back on
   690 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   691 installation location of the Proof General distribution.
   692 
   693 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   694 the Isabelle process into a JVM/Scala application.  See
   695 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   696 process wrapper has been discontinued.)
   697 
   698 * Status messages (with exact source position information) are
   699 emitted, if proper markup print mode is enabled.  This allows
   700 user-interface components to provide detailed feedback on internal
   701 prover operations.
   702 
   703 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   704 
   705 
   706 
   707 New in Isabelle2008 (June 2008)
   708 -------------------------------
   709 
   710 *** General ***
   711 
   712 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   713 and updated, with formally checked references as hyperlinks.
   714 
   715 * Theory loader: use_thy (and similar operations) no longer set the
   716 implicit ML context, which was occasionally hard to predict and in
   717 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   718 provides a proper context already.
   719 
   720 * Theory loader: old-style ML proof scripts being *attached* to a thy
   721 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   722 'use' within a theory file will do the job.
   723 
   724 * Name space merge now observes canonical order, i.e. the second space
   725 is inserted into the first one, while existing entries in the first
   726 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   727 swap theory imports.
   728 
   729 * Syntax: symbol \<chi> is now considered a letter.  Potential
   730 INCOMPATIBILITY in identifier syntax etc.
   731 
   732 * Outer syntax: string tokens no longer admit escaped white space,
   733 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   734 white space without escapes.
   735 
   736 * Outer syntax: string tokens may contain arbitrary character codes
   737 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   738 "foo_bar".
   739 
   740 
   741 *** Pure ***
   742 
   743 * Context-dependent token translations.  Default setup reverts locally
   744 fixed variables, and adds hilite markup for undeclared frees.
   745 
   746 * Unused theorems can be found using the new command 'unused_thms'.
   747 There are three ways of invoking it:
   748 
   749 (1) unused_thms
   750      Only finds unused theorems in the current theory.
   751 
   752 (2) unused_thms thy_1 ... thy_n -
   753      Finds unused theorems in the current theory and all of its ancestors,
   754      excluding the theories thy_1 ... thy_n and all of their ancestors.
   755 
   756 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   757      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   758      their ancestors, excluding the theories thy_1 ... thy_n and all of
   759      their ancestors.
   760 
   761 In order to increase the readability of the list produced by
   762 unused_thms, theorems that have been created by a particular instance
   763 of a theory command such as 'inductive' or 'function' are considered
   764 to belong to the same "group", meaning that if at least one theorem in
   765 this group is used, the other theorems in the same group are no longer
   766 reported as unused.  Moreover, if all theorems in the group are
   767 unused, only one theorem in the group is displayed.
   768 
   769 Note that proof objects have to be switched on in order for
   770 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   771 usually the case when using Proof General with the default settings).
   772 
   773 * Authentic naming of facts disallows ad-hoc overwriting of previous
   774 theorems within the same name space.  INCOMPATIBILITY, need to remove
   775 duplicate fact bindings, or even accidental fact duplications.  Note
   776 that tools may maintain dynamically scoped facts systematically, using
   777 PureThy.add_thms_dynamic.
   778 
   779 * Command 'hide' now allows to hide from "fact" name space as well.
   780 
   781 * Eliminated destructive theorem database, simpset, claset, and
   782 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   783 update of theories within ML code.
   784 
   785 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   786 INCOMPATIBILITY, object-logics depending on former Pure require
   787 additional setup PureThy.old_appl_syntax_setup; object-logics
   788 depending on former CPure need to refer to Pure.
   789 
   790 * Commands 'use' and 'ML' are now purely functional, operating on
   791 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   792 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   793 INCOMPATIBILITY.
   794 
   795 * Command 'setup': discontinued implicit version with ML reference.
   796 
   797 * Instantiation target allows for simultaneous specification of class
   798 instance operations together with an instantiation proof.
   799 Type-checking phase allows to refer to class operations uniformly.
   800 See src/HOL/Complex/Complex.thy for an Isar example and
   801 src/HOL/Library/Eval.thy for an ML example.
   802 
   803 * Indexing of literal facts: be more serious about including only
   804 facts from the visible specification/proof context, but not the
   805 background context (locale etc.).  Affects `prop` notation and method
   806 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   807 situations.
   808 
   809 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   810 "(open)" option, which used to expose internal bound variables to the
   811 proof text.
   812 
   813 * Isar statements: removed obsolete case "rule_context".
   814 INCOMPATIBILITY, better use explicit fixes/assumes.
   815 
   816 * Locale proofs: default proof step now includes 'unfold_locales';
   817 hence 'proof' without argument may be used to unfold locale
   818 predicates.
   819 
   820 
   821 *** Document preparation ***
   822 
   823 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   824 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   825 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   826 spot); renamed link color from "darkblue" to "linkcolor" (default
   827 value unchanged, can be redefined via \definecolor); no longer sets
   828 "a4paper" option (unnecessary or even intrusive).
   829 
   830 * Antiquotation @{lemma A method} proves proposition A by the given
   831 method (either a method name or a method name plus (optional) method
   832 arguments in parentheses) and prints A just like @{prop A}.
   833 
   834 
   835 *** HOL ***
   836 
   837 * New primrec package.  Specification syntax conforms in style to
   838 definition/function/....  No separate induction rule is provided.  The
   839 "primrec" command distinguishes old-style and new-style specifications
   840 by syntax.  The former primrec package is now named OldPrimrecPackage.
   841 When adjusting theories, beware: constants stemming from new-style
   842 primrec specifications have authentic syntax.
   843 
   844 * Metis prover is now an order of magnitude faster, and also works
   845 with multithreading.
   846 
   847 * Metis: the maximum number of clauses that can be produced from a
   848 theorem is now given by the attribute max_clauses.  Theorems that
   849 exceed this number are ignored, with a warning printed.
   850 
   851 * Sledgehammer no longer produces structured proofs by default. To
   852 enable, declare [[sledgehammer_full = true]].  Attributes
   853 reconstruction_modulus, reconstruction_sorts renamed
   854 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   855 
   856 * Method "induct_scheme" derives user-specified induction rules
   857 from well-founded induction and completeness of patterns. This factors
   858 out some operations that are done internally by the function package
   859 and makes them available separately.  See
   860 src/HOL/ex/Induction_Scheme.thy for examples.
   861 
   862 * More flexible generation of measure functions for termination
   863 proofs: Measure functions can be declared by proving a rule of the
   864 form "is_measure f" and giving it the [measure_function] attribute.
   865 The "is_measure" predicate is logically meaningless (always true), and
   866 just guides the heuristic.  To find suitable measure functions, the
   867 termination prover sets up the goal "is_measure ?f" of the appropriate
   868 type and generates all solutions by prolog-style backwards proof using
   869 the declared rules.
   870 
   871 This setup also deals with rules like 
   872 
   873   "is_measure f ==> is_measure (list_size f)"
   874 
   875 which accommodates nested datatypes that recurse through lists.
   876 Similar rules are predeclared for products and option types.
   877 
   878 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   879 
   880   INCOMPATIBILITIES:
   881 
   882   - Definitions of overloaded constants on sets have to be replaced by
   883     definitions on => and bool.
   884 
   885   - Some definitions of overloaded operators on sets can now be proved
   886     using the definitions of the operators on => and bool.  Therefore,
   887     the following theorems have been renamed:
   888 
   889       subset_def   -> subset_eq
   890       psubset_def  -> psubset_eq
   891       set_diff_def -> set_diff_eq
   892       Compl_def    -> Compl_eq
   893       Sup_set_def  -> Sup_set_eq
   894       Inf_set_def  -> Inf_set_eq
   895       sup_set_def  -> sup_set_eq
   896       inf_set_def  -> inf_set_eq
   897 
   898   - Due to the incompleteness of the HO unification algorithm, some
   899     rules such as subst may require manual instantiation, if some of
   900     the unknowns in the rule is a set.
   901 
   902   - Higher order unification and forward proofs:
   903     The proof pattern
   904 
   905       have "P (S::'a set)" <...>
   906       then have "EX S. P S" ..
   907 
   908     no longer works (due to the incompleteness of the HO unification
   909     algorithm) and must be replaced by the pattern
   910 
   911       have "EX S. P S"
   912       proof
   913         show "P S" <...>
   914       qed
   915 
   916   - Calculational reasoning with subst (or similar rules):
   917     The proof pattern
   918 
   919       have "P (S::'a set)" <...>
   920       also have "S = T" <...>
   921       finally have "P T" .
   922 
   923     no longer works (for similar reasons as the previous example) and
   924     must be replaced by something like
   925 
   926       have "P (S::'a set)" <...>
   927       moreover have "S = T" <...>
   928       ultimately have "P T" by simp
   929 
   930   - Tactics or packages written in ML code:
   931     Code performing pattern matching on types via
   932 
   933       Type ("set", [T]) => ...
   934 
   935     must be rewritten. Moreover, functions like strip_type or
   936     binder_types no longer return the right value when applied to a
   937     type of the form
   938 
   939       T1 => ... => Tn => U => bool
   940 
   941     rather than
   942 
   943       T1 => ... => Tn => U set
   944 
   945 * Merged theories Wellfounded_Recursion, Accessible_Part and
   946 Wellfounded_Relations to theory Wellfounded.
   947 
   948 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   949 
   950 * Class finite no longer treats UNIV as class parameter.  Use class
   951 enum from theory Library/Enum instead to achieve a similar effect.
   952 INCOMPATIBILITY.
   953 
   954 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   955 and "Cons".  INCOMPATIBILITY.
   956 
   957 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   958 Potential INCOMPATIBILITY.
   959 
   960 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   961 injective_fst_snd removed, use split_eta and prod_eqI instead.
   962 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   963 
   964 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   965 the same name in theory Orderings:
   966 
   967   less_trans
   968   less_linear
   969   le_imp_less_or_eq
   970   le_less_trans
   971   less_le_trans
   972   less_not_sym
   973   less_asym
   974 
   975 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   976 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   977 and different variable names.
   978 
   979 * Library/Option_ord.thy: Canonical order on option type.
   980 
   981 * Library/RBT.thy: Red-black trees, an efficient implementation of
   982 finite maps.
   983 
   984 * Library/Countable.thy: Type class for countable types.
   985 
   986 * Theory Int: The representation of numerals has changed.  The infix
   987 operator BIT and the bit datatype with constructors B0 and B1 have
   988 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   989 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   990 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   991 accordingly.
   992 
   993 * Theory Nat: definition of <= and < on natural numbers no longer
   994 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   995 le_def and less_def have disappeared.  Consider lemmas not_less
   996 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   997 
   998 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   999 (whose purpose mainly is for various fold_set functionals) have been
  1000 abandoned in favor of the existing algebraic classes
  1001 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1002 lower_semilattice (resp. upper_semilattice) and linorder.
  1003 INCOMPATIBILITY.
  1004 
  1005 * Theory Transitive_Closure: induct and cases rules now declare proper
  1006 case_names ("base" and "step").  INCOMPATIBILITY.
  1007 
  1008 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1009 lattices.  The form set-specific version is available as
  1010 Inductive.lfp_ordinal_induct_set.
  1011 
  1012 * Renamed theorems "power.simps" to "power_int.simps".
  1013 INCOMPATIBILITY.
  1014 
  1015 * Class semiring_div provides basic abstract properties of semirings
  1016 with division and modulo operations.  Subsumes former class dvd_mod.
  1017 
  1018 * Merged theories IntDef, Numeral and IntArith into unified theory
  1019 Int.  INCOMPATIBILITY.
  1020 
  1021 * Theory Library/Code_Index: type "index" now represents natural
  1022 numbers rather than integers.  INCOMPATIBILITY.
  1023 
  1024 * New class "uminus" with operation "uminus" (split of from class
  1025 "minus" which now only has operation "minus", binary).
  1026 INCOMPATIBILITY.
  1027 
  1028 * Constants "card", "internal_split", "option_map" now with authentic
  1029 syntax.  INCOMPATIBILITY.
  1030 
  1031 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1032 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1033 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1034 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1035 Sup_set_def, le_def, less_def, option_map_def now with object
  1036 equality.  INCOMPATIBILITY.
  1037 
  1038 * Records. Removed K_record, and replaced it by pure lambda term
  1039 %x. c. The simplifier setup is now more robust against eta expansion.
  1040 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1041 
  1042 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1043 
  1044 * Library/ListVector: new theory of arithmetic vector operations.
  1045 
  1046 * Library/Order_Relation: new theory of various orderings as sets of
  1047 pairs.  Defines preorders, partial orders, linear orders and
  1048 well-orders on sets and on types.
  1049 
  1050 
  1051 *** ZF ***
  1052 
  1053 * Renamed some theories to allow to loading both ZF and HOL in the
  1054 same session:
  1055 
  1056   Datatype  -> Datatype_ZF
  1057   Inductive -> Inductive_ZF
  1058   Int       -> Int_ZF
  1059   IntDiv    -> IntDiv_ZF
  1060   Nat       -> Nat_ZF
  1061   List      -> List_ZF
  1062   Main      -> Main_ZF
  1063 
  1064 INCOMPATIBILITY: ZF theories that import individual theories below
  1065 Main might need to be adapted.  Regular theory Main is still
  1066 available, as trivial extension of Main_ZF.
  1067 
  1068 
  1069 *** ML ***
  1070 
  1071 * ML within Isar: antiquotation @{const name} or @{const
  1072 name(typargs)} produces statically-checked Const term.
  1073 
  1074 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1075 (of the same name).  Removed obsolete print command.
  1076 
  1077 * Removed obsolete "use_legacy_bindings" function.
  1078 
  1079 * The ``print mode'' is now a thread-local value derived from a global
  1080 template (the former print_mode reference), thus access becomes
  1081 non-critical.  The global print_mode reference is for session
  1082 management only; user-code should use print_mode_value,
  1083 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1084 
  1085 * Functions system/system_out provide a robust way to invoke external
  1086 shell commands, with propagation of interrupts (requires Poly/ML
  1087 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1088 
  1089 
  1090 *** System ***
  1091 
  1092 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1093 in accordance with Proof General 3.7, which prefers GNU emacs.
  1094 
  1095 * isatool tty runs Isabelle process with plain tty interaction;
  1096 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1097 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1098 
  1099 * isatool browser now works with Cygwin as well, using general
  1100 "javapath" function defined in Isabelle process environment.
  1101 
  1102 * YXML notation provides a simple and efficient alternative to
  1103 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1104 isatool yxml as described in the Isabelle system manual.
  1105 
  1106 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1107 provides general wrapper for managing an Isabelle process in a robust
  1108 fashion, with ``cooked'' output from stdin/stderr.
  1109 
  1110 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1111 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1112 
  1113 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1114 way of changing the user's settings is via
  1115 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1116 script.
  1117 
  1118 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1119 cores of the underlying machine, which is a good starting point for
  1120 optimal performance tuning.  The corresponding usedir option -M allows
  1121 "max" as an alias for "0".  WARNING: does not work on certain versions
  1122 of Mac OS (with Poly/ML 5.1).
  1123 
  1124 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1125 adverse effect of Isabelle flooding interactive front-ends (notably
  1126 ProofGeneral / XEmacs).
  1127 
  1128 
  1129 
  1130 New in Isabelle2007 (November 2007)
  1131 -----------------------------------
  1132 
  1133 *** General ***
  1134 
  1135 * More uniform information about legacy features, notably a
  1136 warning/error of "Legacy feature: ...", depending on the state of the
  1137 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1138 legacy features will disappear eventually.
  1139 
  1140 * Theory syntax: the header format ``theory A = B + C:'' has been
  1141 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1142 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1143 
  1144 * Theory syntax: the old non-Isar theory file format has been
  1145 discontinued altogether.  Note that ML proof scripts may still be used
  1146 with Isar theories; migration is usually quite simple with the ML
  1147 function use_legacy_bindings.  INCOMPATIBILITY.
  1148 
  1149 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1150 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1151 quotes.
  1152 
  1153 * Theory loader: be more serious about observing the static theory
  1154 header specifications (including optional directories), but not the
  1155 accidental file locations of previously successful loads.  The strict
  1156 update policy of former update_thy is now already performed by
  1157 use_thy, so the former has been removed; use_thys updates several
  1158 theories simultaneously, just as 'imports' within a theory header
  1159 specification, but without merging the results.  Potential
  1160 INCOMPATIBILITY: may need to refine theory headers and commands
  1161 ROOT.ML which depend on load order.
  1162 
  1163 * Theory loader: optional support for content-based file
  1164 identification, instead of the traditional scheme of full physical
  1165 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1166 (cf. the system manual).  The new scheme allows to work with
  1167 non-finished theories in persistent session images, such that source
  1168 files may be moved later on without requiring reloads.
  1169 
  1170 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1171 file (with the same base name as the theory) are considered a legacy
  1172 feature, which will disappear eventually. Even now, the theory loader
  1173 no longer maintains dependencies on such files.
  1174 
  1175 * Syntax: the scope for resolving ambiguities via type-inference is
  1176 now limited to individual terms, instead of whole simultaneous
  1177 specifications as before. This greatly reduces the complexity of the
  1178 syntax module and improves flexibility by separating parsing and
  1179 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1180 'fixes' etc.) are required in rare situations.
  1181 
  1182 * Syntax: constants introduced by new-style packages ('definition',
  1183 'abbreviation' etc.) are passed through the syntax module in
  1184 ``authentic mode''. This means that associated mixfix annotations
  1185 really stick to such constants, independently of potential name space
  1186 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1187 trees are represented slightly differently, may need to adapt syntax
  1188 translations accordingly. Use CONST marker in 'translations' and
  1189 @{const_syntax} antiquotation in 'parse_translation' etc.
  1190 
  1191 * Legacy goal package: reduced interface to the bare minimum required
  1192 to keep existing proof scripts running.  Most other user-level
  1193 functions are now part of the OldGoals structure, which is *not* open
  1194 by default (consider isatool expandshort before open OldGoals).
  1195 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1196 these tend to cause confusion about the actual goal (!) context being
  1197 used here, which is not necessarily the same as the_context().
  1198 
  1199 * Command 'find_theorems': supports "*" wild-card in "name:"
  1200 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1201 support a specific search form (see ProofGeneral/CHANGES).
  1202 
  1203 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1204 by default, which means that "prems" (and also "fixed variables") are
  1205 suppressed from proof state output.  Note that the ProofGeneral
  1206 settings mechanism allows to change and save options persistently, but
  1207 older versions of Isabelle will fail to start up if a negative prems
  1208 limit is imposed.
  1209 
  1210 * Local theory targets may be specified by non-nested blocks of
  1211 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1212 contain definitions, theorems etc., including any derived mechanism
  1213 that has been implemented on top of these primitives.  This concept
  1214 generalizes the existing ``theorem (in ...)'' towards more versatility
  1215 and scalability.
  1216 
  1217 * Proof General interface: proper undo of final 'end' command;
  1218 discontinued Isabelle/classic mode (ML proof scripts).
  1219 
  1220 
  1221 *** Document preparation ***
  1222 
  1223 * Added antiquotation @{theory name} which prints the given name,
  1224 after checking that it refers to a valid ancestor theory in the
  1225 current context.
  1226 
  1227 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1228 check the given source text as ML type/structure, printing verbatim.
  1229 
  1230 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1231 "c args == rhs" given in the current context.  (Any number of
  1232 arguments may be given on the LHS.)
  1233 
  1234 
  1235 *** Pure ***
  1236 
  1237 * The 'class' package offers a combination of axclass and locale to
  1238 achieve Haskell-like type classes in Isabelle.  Definitions and
  1239 theorems within a class context produce both relative results (with
  1240 implicit parameters according to the locale context), and polymorphic
  1241 constants with qualified polymorphism (according to the class
  1242 context).  Within the body context of a 'class' target, a separate
  1243 syntax layer ("user space type system") takes care of converting
  1244 between global polymorphic consts and internal locale representation.
  1245 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1246 "isatool doc classes" provides a tutorial.
  1247 
  1248 * Generic code generator framework allows to generate executable
  1249 code for ML and Haskell (including Isabelle classes).  A short usage
  1250 sketch:
  1251 
  1252     internal compilation:
  1253         export_code <list of constants (term syntax)> in SML
  1254     writing SML code to a file:
  1255         export_code <list of constants (term syntax)> in SML <filename>
  1256     writing OCaml code to a file:
  1257         export_code <list of constants (term syntax)> in OCaml <filename>
  1258     writing Haskell code to a bunch of files:
  1259         export_code <list of constants (term syntax)> in Haskell <filename>
  1260 
  1261     evaluating closed propositions to True/False using code generation:
  1262         method ``eval''
  1263 
  1264 Reasonable default setup of framework in HOL.
  1265 
  1266 Theorem attributs for selecting and transforming function equations theorems:
  1267 
  1268     [code fun]:        select a theorem as function equation for a specific constant
  1269     [code fun del]:    deselect a theorem as function equation for a specific constant
  1270     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1271     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1272 
  1273 User-defined serializations (target in {SML, OCaml, Haskell}):
  1274 
  1275     code_const <and-list of constants (term syntax)>
  1276       {(target) <and-list of const target syntax>}+
  1277 
  1278     code_type <and-list of type constructors>
  1279       {(target) <and-list of type target syntax>}+
  1280 
  1281     code_instance <and-list of instances>
  1282       {(target)}+
  1283         where instance ::= <type constructor> :: <class>
  1284 
  1285     code_class <and_list of classes>
  1286       {(target) <and-list of class target syntax>}+
  1287         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1288 
  1289 code_instance and code_class only are effective to target Haskell.
  1290 
  1291 For example usage see src/HOL/ex/Codegenerator.thy and
  1292 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1293 generation from Isabelle/HOL theories is available via "isatool doc
  1294 codegen".
  1295 
  1296 * Code generator: consts in 'consts_code' Isar commands are now
  1297 referred to by usual term syntax (including optional type
  1298 annotations).
  1299 
  1300 * Command 'no_translations' removes translation rules from theory
  1301 syntax.
  1302 
  1303 * Overloaded definitions are now actually checked for acyclic
  1304 dependencies.  The overloading scheme is slightly more general than
  1305 that of Haskell98, although Isabelle does not demand an exact
  1306 correspondence to type class and instance declarations.
  1307 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1308 exotic versions of overloading -- at the discretion of the user!
  1309 
  1310 Polymorphic constants are represented via type arguments, i.e. the
  1311 instantiation that matches an instance against the most general
  1312 declaration given in the signature.  For example, with the declaration
  1313 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1314 as c(nat).  Overloading is essentially simultaneous structural
  1315 recursion over such type arguments.  Incomplete specification patterns
  1316 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1317 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1318 Command 'print_theory' outputs the normalized system of recursive
  1319 equations, see section "definitions".
  1320 
  1321 * Configuration options are maintained within the theory or proof
  1322 context (with name and type bool/int/string), providing a very simple
  1323 interface to a poor-man's version of general context data.  Tools may
  1324 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1325 these values using Config.get etc.  Users may change options via an
  1326 associated attribute of the same name.  This form of context
  1327 declaration works particularly well with commands 'declare' or
  1328 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1329 very easy to avoid global references, which would not observe Isar
  1330 toplevel undo/redo and fail to work with multithreading.
  1331 
  1332 Various global ML references of Pure and HOL have been turned into
  1333 configuration options:
  1334 
  1335   Unify.search_bound		unify_search_bound
  1336   Unify.trace_bound		unify_trace_bound
  1337   Unify.trace_simp		unify_trace_simp
  1338   Unify.trace_types		unify_trace_types
  1339   Simplifier.simp_depth_limit	simp_depth_limit
  1340   Blast.depth_limit		blast_depth_limit
  1341   DatatypeProp.dtK		datatype_distinctness_limit
  1342   fast_arith_neq_limit  	fast_arith_neq_limit
  1343   fast_arith_split_limit	fast_arith_split_limit
  1344 
  1345 * Named collections of theorems may be easily installed as context
  1346 data using the functor NamedThmsFun (see also
  1347 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1348 attributes; there is also a toplevel print command.  This facility is
  1349 just a common case of general context data, which is the preferred way
  1350 for anything more complex than just a list of facts in canonical
  1351 order.
  1352 
  1353 * Isar: command 'declaration' augments a local theory by generic
  1354 declaration functions written in ML.  This enables arbitrary content
  1355 being added to the context, depending on a morphism that tells the
  1356 difference of the original declaration context wrt. the application
  1357 context encountered later on.
  1358 
  1359 * Isar: proper interfaces for simplification procedures.  Command
  1360 'simproc_setup' declares named simprocs (with match patterns, and body
  1361 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1362 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1363 
  1364 * Isar: an extra pair of brackets around attribute declarations
  1365 abbreviates a theorem reference involving an internal dummy fact,
  1366 which will be ignored later --- only the effect of the attribute on
  1367 the background context will persist.  This form of in-place
  1368 declarations is particularly useful with commands like 'declare' and
  1369 'using', for example ``have A using [[simproc a]] by simp''.
  1370 
  1371 * Isar: method "assumption" (and implicit closing of subproofs) now
  1372 takes simple non-atomic goal assumptions into account: after applying
  1373 an assumption as a rule the resulting subgoals are solved by atomic
  1374 assumption steps.  This is particularly useful to finish 'obtain'
  1375 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1376 without referring to the original premise "!!x. P x ==> thesis" in the
  1377 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1378 more permissive.
  1379 
  1380 * Isar: implicit use of prems from the Isar proof context is
  1381 considered a legacy feature.  Common applications like ``have A .''
  1382 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1383 referencing facts explicitly here improves readability and
  1384 maintainability of proof texts.
  1385 
  1386 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1387 the obtained context from the course of reasoning!  For example:
  1388 
  1389   assume "EX x y. A x & B y"   -- "any previous fact"
  1390   then guess x and y by clarify
  1391 
  1392 This technique is potentially adventurous, depending on the facts and
  1393 proof tools being involved here.
  1394 
  1395 * Isar: known facts from the proof context may be specified as literal
  1396 propositions, using ASCII back-quote syntax.  This works wherever
  1397 named facts used to be allowed so far, in proof commands, proof
  1398 methods, attributes etc.  Literal facts are retrieved from the context
  1399 according to unification of type and term parameters.  For example,
  1400 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1401 theorems in the current context, then these are valid literal facts:
  1402 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1403 
  1404 There is also a proof method "fact" which does the same composition
  1405 for explicit goal states, e.g. the following proof texts coincide with
  1406 certain special cases of literal facts:
  1407 
  1408   have "A" by fact                 ==  note `A`
  1409   have "A ==> B" by fact           ==  note `A ==> B`
  1410   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1411   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1412 
  1413 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1414 outer syntax.  Thus symbolic identifiers may be used without
  1415 additional white space in declarations like this: ``assume *: A''.
  1416 
  1417 * Isar: 'print_facts' prints all local facts of the current context,
  1418 both named and unnamed ones.
  1419 
  1420 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1421 
  1422   def x == "t" and y == "u"
  1423 
  1424 * Isar: added command 'unfolding', which is structurally similar to
  1425 'using', but affects both the goal state and facts by unfolding given
  1426 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1427 'unfolded' attribute may be replaced by first-class proof text.
  1428 
  1429 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1430 and command 'unfolding' now all support object-level equalities
  1431 (potentially conditional).  The underlying notion of rewrite rule is
  1432 analogous to the 'rule_format' attribute, but *not* that of the
  1433 Simplifier (which is usually more generous).
  1434 
  1435 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1436 premises of a theorem by n. Useful in conjunction with drule.
  1437 
  1438 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1439 method expression within a sandbox consisting of the first N
  1440 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1441 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1442 simplifies all new goals that emerge from applying rule foo to the
  1443 originally first one.
  1444 
  1445 * Isar: schematic goals are no longer restricted to higher-order
  1446 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1447 expected.
  1448 
  1449 * Isar: the conclusion of a long theorem statement is now either
  1450 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1451 (essentially a disjunction of cases with local parameters and
  1452 assumptions).  The latter allows to express general elimination rules
  1453 adequately; in this notation common elimination rules look like this:
  1454 
  1455   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1456     assumes "EX x. P x"
  1457     obtains x where "P x"
  1458 
  1459   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1460     assumes "A & B"
  1461     obtains A and B
  1462 
  1463   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1464     assumes "A | B"
  1465     obtains
  1466       A
  1467     | B
  1468 
  1469 The subsequent classical rules even refer to the formal "thesis"
  1470 explicitly:
  1471 
  1472   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1473     obtains "~ thesis"
  1474 
  1475   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1476     obtains "thesis ==> something"
  1477 
  1478 The actual proof of an 'obtains' statement is analogous to that of the
  1479 Isar proof element 'obtain', only that there may be several cases.
  1480 Optional case names may be specified in parentheses; these will be
  1481 available both in the present proof and as annotations in the
  1482 resulting rule, for later use with the 'cases' method (cf. attribute
  1483 case_names).
  1484 
  1485 * Isar: the assumptions of a long theorem statement are available as
  1486 "assms" fact in the proof context.  This is more appropriate than the
  1487 (historical) "prems", which refers to all assumptions of the current
  1488 context, including those from the target locale, proof body etc.
  1489 
  1490 * Isar: 'print_statement' prints theorems from the current theory or
  1491 proof context in long statement form, according to the syntax of a
  1492 top-level lemma.
  1493 
  1494 * Isar: 'obtain' takes an optional case name for the local context
  1495 introduction rule (default "that").
  1496 
  1497 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1498 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1499 to occur.
  1500 
  1501 * Pure: syntax "CONST name" produces a fully internalized constant
  1502 according to the current context.  This is particularly useful for
  1503 syntax translations that should refer to internal constant
  1504 representations independently of name spaces.
  1505 
  1506 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1507 instead of "FOO ". This allows multiple binder declarations to coexist
  1508 in the same context.  INCOMPATIBILITY.
  1509 
  1510 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1511 primitive that also works in a locale context (both for constants and
  1512 fixed variables). Type declaration and internal syntactic representation
  1513 of given constants retrieved from the context. Likewise, the
  1514 'no_notation' command allows to remove given syntax annotations from the
  1515 current context.
  1516 
  1517 * Isar/locales: new derived specification elements 'axiomatization',
  1518 'definition', 'abbreviation', which support type-inference, admit
  1519 object-level specifications (equality, equivalence).  See also the
  1520 isar-ref manual.  Examples:
  1521 
  1522   axiomatization
  1523     eq  (infix "===" 50) where
  1524     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1525 
  1526   definition "f x y = x + y + 1"
  1527   definition g where "g x = f x x"
  1528 
  1529   abbreviation
  1530     neq  (infix "=!=" 50) where
  1531     "x =!= y == ~ (x === y)"
  1532 
  1533 These specifications may be also used in a locale context.  Then the
  1534 constants being introduced depend on certain fixed parameters, and the
  1535 constant name is qualified by the locale base name.  An internal
  1536 abbreviation takes care for convenient input and output, making the
  1537 parameters implicit and using the original short name.  See also
  1538 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1539 entities from a monomorphic theory.
  1540 
  1541 Presently, abbreviations are only available 'in' a target locale, but
  1542 not inherited by general import expressions.  Also note that
  1543 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1544 'translations' in common applications.  The "no_abbrevs" print mode
  1545 prevents folding of abbreviations in term output.
  1546 
  1547 Concrete syntax is attached to specified constants in internal form,
  1548 independently of name spaces.  The parse tree representation is
  1549 slightly different -- use 'notation' instead of raw 'syntax', and
  1550 'translations' with explicit "CONST" markup to accommodate this.
  1551 
  1552 * Pure/Isar: unified syntax for new-style specification mechanisms
  1553 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1554 full type inference and dummy patterns ("_").  For example:
  1555 
  1556   definition "K x _ = x"
  1557 
  1558   inductive conj for A B
  1559   where "A ==> B ==> conj A B"
  1560 
  1561 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1562 the current context.  Print mode "no_abbrevs" prevents inversion of
  1563 abbreviations on output.
  1564 
  1565 * Isar/locales: improved parameter handling: use of locales "var" and
  1566 "struct" no longer necessary; - parameter renamings are no longer
  1567 required to be injective.  For example, this allows to define
  1568 endomorphisms as locale endom = homom mult mult h.
  1569 
  1570 * Isar/locales: changed the way locales with predicates are defined.
  1571 Instead of accumulating the specification, the imported expression is
  1572 now an interpretation.  INCOMPATIBILITY: different normal form of
  1573 locale expressions.  In particular, in interpretations of locales with
  1574 predicates, goals repesenting already interpreted fragments are not
  1575 removed automatically.  Use methods `intro_locales' and
  1576 `unfold_locales'; see below.
  1577 
  1578 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1579 provide backward reasoning on locales predicates.  The methods are
  1580 aware of interpretations and discharge corresponding goals.
  1581 `intro_locales' is less aggressive then `unfold_locales' and does not
  1582 unfold predicates to assumptions.
  1583 
  1584 * Isar/locales: the order in which locale fragments are accumulated
  1585 has changed.  This enables to override declarations from fragments due
  1586 to interpretations -- for example, unwanted simp rules.
  1587 
  1588 * Isar/locales: interpretation in theories and proof contexts has been
  1589 extended.  One may now specify (and prove) equations, which are
  1590 unfolded in interpreted theorems.  This is useful for replacing
  1591 defined concepts (constants depending on locale parameters) by
  1592 concepts already existing in the target context.  Example:
  1593 
  1594   interpretation partial_order ["op <= :: [int, int] => bool"]
  1595     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1596 
  1597 Typically, the constant `partial_order.less' is created by a
  1598 definition specification element in the context of locale
  1599 partial_order.
  1600 
  1601 * Method "induct": improved internal context management to support
  1602 local fixes and defines on-the-fly. Thus explicit meta-level
  1603 connectives !!  and ==> are rarely required anymore in inductive goals
  1604 (using object-logic connectives for this purpose has been long
  1605 obsolete anyway). Common proof patterns are explained in
  1606 src/HOL/Induct/Common_Patterns.thy, see also
  1607 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1608 examples.
  1609 
  1610 * Method "induct": improved handling of simultaneous goals. Instead of
  1611 introducing object-level conjunction, the statement is now split into
  1612 several conclusions, while the corresponding symbolic cases are nested
  1613 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1614 see src/HOL/Induct/Common_Patterns.thy, for example.
  1615 
  1616 * Method "induct": mutual induction rules are now specified as a list
  1617 of rule sharing the same induction cases. HOL packages usually provide
  1618 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1619 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1620 mutual induction rules differently, i.e. like this:
  1621 
  1622   (induct rule: foo_bar.inducts)
  1623   (induct set: foo bar)
  1624   (induct pred: foo bar)
  1625   (induct type: foo bar)
  1626 
  1627 The ML function ProjectRule.projections turns old-style rules into the
  1628 new format.
  1629 
  1630 * Method "coinduct": dual of induction, see
  1631 src/HOL/Library/Coinductive_List.thy for various examples.
  1632 
  1633 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1634 considered a legacy feature.
  1635 
  1636 * Attribute "symmetric" produces result with standardized schematic
  1637 variables (index 0).  Potential INCOMPATIBILITY.
  1638 
  1639 * Simplifier: by default the simplifier trace only shows top level
  1640 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1641 default. Thus there is less danger of being flooded by the trace. The
  1642 trace indicates where parts have been suppressed.
  1643   
  1644 * Provers/classical: removed obsolete classical version of elim_format
  1645 attribute; classical elim/dest rules are now treated uniformly when
  1646 manipulating the claset.
  1647 
  1648 * Provers/classical: stricter checks to ensure that supplied intro,
  1649 dest and elim rules are well-formed; dest and elim rules must have at
  1650 least one premise.
  1651 
  1652 * Provers/classical: attributes dest/elim/intro take an optional
  1653 weight argument for the rule (just as the Pure versions).  Weights are
  1654 ignored by automated tools, but determine the search order of single
  1655 rule steps.
  1656 
  1657 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1658 where the body does not mention the bound variable.  Note that dummy
  1659 patterns implicitly depend on their context of bounds, which makes
  1660 "{_. _}" match any set comprehension as expected.  Potential
  1661 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1662 constant "_idtdummy" in the binding position.
  1663 
  1664 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1665 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1666 for example "A -> B" => "Pi A (%_. B)".
  1667 
  1668 * Pure: 'class_deps' command visualizes the subclass relation, using
  1669 the graph browser tool.
  1670 
  1671 * Pure: 'print_theory' now suppresses certain internal declarations by
  1672 default; use '!' option for full details.
  1673 
  1674 
  1675 *** HOL ***
  1676 
  1677 * Method "metis" proves goals by applying the Metis general-purpose
  1678 resolution prover (see also http://gilith.com/software/metis/).
  1679 Examples are in the directory MetisExamples.  WARNING: the
  1680 Isabelle/HOL-Metis integration does not yet work properly with
  1681 multi-threading.
  1682   
  1683 * Command 'sledgehammer' invokes external automatic theorem provers as
  1684 background processes.  It generates calls to the "metis" method if
  1685 successful. These can be pasted into the proof.  Users do not have to
  1686 wait for the automatic provers to return.  WARNING: does not really
  1687 work with multi-threading.
  1688 
  1689 * New "auto_quickcheck" feature tests outermost goal statements for
  1690 potential counter-examples.  Controlled by ML references
  1691 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1692 5000 milliseconds).  Fails silently if statements is outside of
  1693 executable fragment, or any other codgenerator problem occurs.
  1694 
  1695 * New constant "undefined" with axiom "undefined x = undefined".
  1696 
  1697 * Added class "HOL.eq", allowing for code generation with polymorphic
  1698 equality.
  1699 
  1700 * Some renaming of class constants due to canonical name prefixing in
  1701 the new 'class' package:
  1702 
  1703     HOL.abs ~> HOL.abs_class.abs
  1704     HOL.divide ~> HOL.divide_class.divide
  1705     0 ~> HOL.zero_class.zero
  1706     1 ~> HOL.one_class.one
  1707     op + ~> HOL.plus_class.plus
  1708     op - ~> HOL.minus_class.minus
  1709     uminus ~> HOL.minus_class.uminus
  1710     op * ~> HOL.times_class.times
  1711     op < ~> HOL.ord_class.less
  1712     op <= > HOL.ord_class.less_eq
  1713     Nat.power ~> Power.power_class.power
  1714     Nat.size ~> Nat.size_class.size
  1715     Numeral.number_of ~> Numeral.number_class.number_of
  1716     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1717     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1718     Orderings.min ~> Orderings.ord_class.min
  1719     Orderings.max ~> Orderings.ord_class.max
  1720     Divides.op div ~> Divides.div_class.div
  1721     Divides.op mod ~> Divides.div_class.mod
  1722     Divides.op dvd ~> Divides.div_class.dvd
  1723 
  1724 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1725 
  1726 a) User-defined constants using any of the names "plus", "minus",
  1727 "times", "less" or "less_eq". The standard syntax translations for
  1728 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1729 names.
  1730 
  1731 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1732 INCOMPATIBILITY: use more specific names.
  1733 
  1734 c) Permutative equations (e.g. "a + b = b + a")
  1735 Since the change of names also changes the order of terms, permutative
  1736 rewrite rules may get applied in a different order. Experience shows
  1737 that this is rarely the case (only two adaptions in the whole Isabelle
  1738 distribution).  INCOMPATIBILITY: rewrite proofs
  1739 
  1740 d) ML code directly refering to constant names
  1741 This in general only affects hand-written proof tactics, simprocs and
  1742 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1743 Consider using @{const_name} antiquotation.
  1744 
  1745 * New class "default" with associated constant "default".
  1746 
  1747 * Function "sgn" is now overloaded and available on int, real, complex
  1748 (and other numeric types), using class "sgn".  Two possible defs of
  1749 sgn are given as equational assumptions in the classes sgn_if and
  1750 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1751 INCOMPATIBILITY.
  1752 
  1753 * Locale "partial_order" now unified with class "order" (cf. theory
  1754 Orderings), added parameter "less".  INCOMPATIBILITY.
  1755 
  1756 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1757 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1758 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1759 
  1760 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1761 changed order of proof goals in instance proofs.
  1762 
  1763 * The transitivity reasoner for partial and linear orders is set up
  1764 for classes "order" and "linorder".  Instances of the reasoner are available
  1765 in all contexts importing or interpreting the corresponding locales.
  1766 Method "order" invokes the reasoner separately; the reasoner
  1767 is also integrated with the Simplifier as a solver.  Diagnostic
  1768 command 'print_orders' shows the available instances of the reasoner
  1769 in the current context.
  1770 
  1771 * Localized monotonicity predicate in theory "Orderings"; integrated
  1772 lemmas max_of_mono and min_of_mono with this predicate.
  1773 INCOMPATIBILITY.
  1774 
  1775 * Formulation of theorem "dense" changed slightly due to integration
  1776 with new class dense_linear_order.
  1777 
  1778 * Uniform lattice theory development in HOL.
  1779 
  1780     constants "meet" and "join" now named "inf" and "sup"
  1781     constant "Meet" now named "Inf"
  1782 
  1783     classes "meet_semilorder" and "join_semilorder" now named
  1784       "lower_semilattice" and "upper_semilattice"
  1785     class "lorder" now named "lattice"
  1786     class "comp_lat" now named "complete_lattice"
  1787 
  1788     Instantiation of lattice classes allows explicit definitions
  1789     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1790 
  1791   INCOMPATIBILITY.  Theorem renames:
  1792 
  1793     meet_left_le            ~> inf_le1
  1794     meet_right_le           ~> inf_le2
  1795     join_left_le            ~> sup_ge1
  1796     join_right_le           ~> sup_ge2
  1797     meet_join_le            ~> inf_sup_ord
  1798     le_meetI                ~> le_infI
  1799     join_leI                ~> le_supI
  1800     le_meet                 ~> le_inf_iff
  1801     le_join                 ~> ge_sup_conv
  1802     meet_idempotent         ~> inf_idem
  1803     join_idempotent         ~> sup_idem
  1804     meet_comm               ~> inf_commute
  1805     join_comm               ~> sup_commute
  1806     meet_leI1               ~> le_infI1
  1807     meet_leI2               ~> le_infI2
  1808     le_joinI1               ~> le_supI1
  1809     le_joinI2               ~> le_supI2
  1810     meet_assoc              ~> inf_assoc
  1811     join_assoc              ~> sup_assoc
  1812     meet_left_comm          ~> inf_left_commute
  1813     meet_left_idempotent    ~> inf_left_idem
  1814     join_left_comm          ~> sup_left_commute
  1815     join_left_idempotent    ~> sup_left_idem
  1816     meet_aci                ~> inf_aci
  1817     join_aci                ~> sup_aci
  1818     le_def_meet             ~> le_iff_inf
  1819     le_def_join             ~> le_iff_sup
  1820     join_absorp2            ~> sup_absorb2
  1821     join_absorp1            ~> sup_absorb1
  1822     meet_absorp1            ~> inf_absorb1
  1823     meet_absorp2            ~> inf_absorb2
  1824     meet_join_absorp        ~> inf_sup_absorb
  1825     join_meet_absorp        ~> sup_inf_absorb
  1826     distrib_join_le         ~> distrib_sup_le
  1827     distrib_meet_le         ~> distrib_inf_le
  1828 
  1829     add_meet_distrib_left   ~> add_inf_distrib_left
  1830     add_join_distrib_left   ~> add_sup_distrib_left
  1831     is_join_neg_meet        ~> is_join_neg_inf
  1832     is_meet_neg_join        ~> is_meet_neg_sup
  1833     add_meet_distrib_right  ~> add_inf_distrib_right
  1834     add_join_distrib_right  ~> add_sup_distrib_right
  1835     add_meet_join_distribs  ~> add_sup_inf_distribs
  1836     join_eq_neg_meet        ~> sup_eq_neg_inf
  1837     meet_eq_neg_join        ~> inf_eq_neg_sup
  1838     add_eq_meet_join        ~> add_eq_inf_sup
  1839     meet_0_imp_0            ~> inf_0_imp_0
  1840     join_0_imp_0            ~> sup_0_imp_0
  1841     meet_0_eq_0             ~> inf_0_eq_0
  1842     join_0_eq_0             ~> sup_0_eq_0
  1843     neg_meet_eq_join        ~> neg_inf_eq_sup
  1844     neg_join_eq_meet        ~> neg_sup_eq_inf
  1845     join_eq_if              ~> sup_eq_if
  1846 
  1847     mono_meet               ~> mono_inf
  1848     mono_join               ~> mono_sup
  1849     meet_bool_eq            ~> inf_bool_eq
  1850     join_bool_eq            ~> sup_bool_eq
  1851     meet_fun_eq             ~> inf_fun_eq
  1852     join_fun_eq             ~> sup_fun_eq
  1853     meet_set_eq             ~> inf_set_eq
  1854     join_set_eq             ~> sup_set_eq
  1855     meet1_iff               ~> inf1_iff
  1856     meet2_iff               ~> inf2_iff
  1857     meet1I                  ~> inf1I
  1858     meet2I                  ~> inf2I
  1859     meet1D1                 ~> inf1D1
  1860     meet2D1                 ~> inf2D1
  1861     meet1D2                 ~> inf1D2
  1862     meet2D2                 ~> inf2D2
  1863     meet1E                  ~> inf1E
  1864     meet2E                  ~> inf2E
  1865     join1_iff               ~> sup1_iff
  1866     join2_iff               ~> sup2_iff
  1867     join1I1                 ~> sup1I1
  1868     join2I1                 ~> sup2I1
  1869     join1I1                 ~> sup1I1
  1870     join2I2                 ~> sup1I2
  1871     join1CI                 ~> sup1CI
  1872     join2CI                 ~> sup2CI
  1873     join1E                  ~> sup1E
  1874     join2E                  ~> sup2E
  1875 
  1876     is_meet_Meet            ~> is_meet_Inf
  1877     Meet_bool_def           ~> Inf_bool_def
  1878     Meet_fun_def            ~> Inf_fun_def
  1879     Meet_greatest           ~> Inf_greatest
  1880     Meet_lower              ~> Inf_lower
  1881     Meet_set_def            ~> Inf_set_def
  1882 
  1883     Sup_def                 ~> Sup_Inf
  1884     Sup_bool_eq             ~> Sup_bool_def
  1885     Sup_fun_eq              ~> Sup_fun_def
  1886     Sup_set_eq              ~> Sup_set_def
  1887 
  1888     listsp_meetI            ~> listsp_infI
  1889     listsp_meet_eq          ~> listsp_inf_eq
  1890 
  1891     meet_min                ~> inf_min
  1892     join_max                ~> sup_max
  1893 
  1894 * Added syntactic class "size"; overloaded constant "size" now has
  1895 type "'a::size ==> bool"
  1896 
  1897 * Internal reorganisation of `size' of datatypes: size theorems
  1898 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1899 simplification rules by default!); theorems "prod.size" now named
  1900 "*.size".
  1901 
  1902 * Class "div" now inherits from class "times" rather than "type".
  1903 INCOMPATIBILITY.
  1904 
  1905 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1906 Linorder etc.  have disappeared; operations defined in terms of
  1907 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1908 
  1909 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1910 
  1911 * HOL-Word: New extensive library and type for generic, fixed size
  1912 machine words, with arithemtic, bit-wise, shifting and rotating
  1913 operations, reflection into int, nat, and bool lists, automation for
  1914 linear arithmetic (by automatic reflection into nat or int), including
  1915 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1916 arithmetic type classes, supporting automatic simplification of
  1917 numerals on all operations.
  1918 
  1919 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1920 
  1921 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1922 
  1923 * Code generator library theories:
  1924   - Code_Integer represents HOL integers by big integer literals in target
  1925     languages.
  1926   - Code_Char represents HOL characters by character literals in target
  1927     languages.
  1928   - Code_Char_chr like Code_Char, but also offers treatment of character
  1929     codes; includes Code_Integer.
  1930   - Executable_Set allows to generate code for finite sets using lists.
  1931   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1932     denominator).
  1933   - Executable_Real implements a subset of real numbers, namly those
  1934     representable by rational numbers.
  1935   - Efficient_Nat implements natural numbers by integers, which in general will
  1936     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1937     includes Code_Integer.
  1938   - Code_Index provides an additional datatype index which is mapped to
  1939     target-language built-in integers.
  1940   - Code_Message provides an additional datatype message_string which is isomorphic to
  1941     strings; messages are mapped to target-language strings.
  1942 
  1943 * New package for inductive predicates
  1944 
  1945   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1946 
  1947     inductive
  1948       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1949       for z_1 :: U_1 and ... and z_n :: U_m
  1950     where
  1951       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1952     | ...
  1953 
  1954   with full support for type-inference, rather than
  1955 
  1956     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1957 
  1958     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1959     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1960 
  1961     inductive "s z_1 ... z_m"
  1962     intros
  1963       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1964       ...
  1965 
  1966   For backward compatibility, there is a wrapper allowing inductive
  1967   sets to be defined with the new package via
  1968 
  1969     inductive_set
  1970       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1971       for z_1 :: U_1 and ... and z_n :: U_m
  1972     where
  1973       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1974     | ...
  1975 
  1976   or
  1977 
  1978     inductive_set
  1979       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1980       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1981       for z_1 :: U_1 and ... and z_n :: U_m
  1982     where
  1983       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1984     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1985     | ...
  1986 
  1987   if the additional syntax "p ..." is required.
  1988 
  1989   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1990   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1991 
  1992   INCOMPATIBILITIES:
  1993 
  1994   - Since declaration and definition of inductive sets or predicates
  1995     is no longer separated, abbreviations involving the newly
  1996     introduced sets or predicates must be specified together with the
  1997     introduction rules after the 'where' keyword (see above), rather
  1998     than before the actual inductive definition.
  1999 
  2000   - The variables in induction and elimination rules are now
  2001     quantified in the order of their occurrence in the introduction
  2002     rules, rather than in alphabetical order. Since this may break
  2003     some proofs, these proofs either have to be repaired, e.g. by
  2004     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2005     statements of the form
  2006 
  2007       case (rule_i a_i_1 ... a_i_{k_i})
  2008 
  2009     or the old order of quantification has to be restored by explicitly adding
  2010     meta-level quantifiers in the introduction rules, i.e.
  2011 
  2012       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2013 
  2014   - The format of the elimination rules is now
  2015 
  2016       p z_1 ... z_m x_1 ... x_n ==>
  2017         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2018         ==> ... ==> P
  2019 
  2020     for predicates and
  2021 
  2022       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2023         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2024         ==> ... ==> P
  2025 
  2026     for sets rather than
  2027 
  2028       x : s z_1 ... z_m ==>
  2029         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2030         ==> ... ==> P
  2031 
  2032     This may require terms in goals to be expanded to n-tuples
  2033     (e.g. using case_tac or simplification with the split_paired_all
  2034     rule) before the above elimination rule is applicable.
  2035 
  2036   - The elimination or case analysis rules for (mutually) inductive
  2037     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2038     list of rules "p_1_..._p_k.elims" is no longer available.
  2039 
  2040 * New package "function"/"fun" for general recursive functions,
  2041 supporting mutual and nested recursion, definitions in local contexts,
  2042 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2043 for small examples, and the separate tutorial on the function
  2044 package. The old recdef "package" is still available as before, but
  2045 users are encouraged to use the new package.
  2046 
  2047 * Method "lexicographic_order" automatically synthesizes termination
  2048 relations as lexicographic combinations of size measures. 
  2049 
  2050 * Case-expressions allow arbitrary constructor-patterns (including
  2051 "_") and take their order into account, like in functional
  2052 programming.  Internally, this is translated into nested
  2053 case-expressions; missing cases are added and mapped to the predefined
  2054 constant "undefined". In complicated cases printing may no longer show
  2055 the original input but the internal form. Lambda-abstractions allow
  2056 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2057 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2058 variable.
  2059 
  2060 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2061 is an abbreviation for "of_nat :: nat => int". The simplification
  2062 rules for "of_nat" have been changed to work like "int" did
  2063 previously.  Potential INCOMPATIBILITY:
  2064   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2065   - of_nat_diff and of_nat_mult are no longer default simp rules
  2066 
  2067 * Method "algebra" solves polynomial equations over (semi)rings using
  2068 Groebner bases. The (semi)ring structure is defined by locales and the
  2069 tool setup depends on that generic context. Installing the method for
  2070 a specific type involves instantiating the locale and possibly adding
  2071 declarations for computation on the coefficients.  The method is
  2072 already instantiated for natural numbers and for the axiomatic class
  2073 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2074 CALCULEMUS 2007 for the general principles underlying this
  2075 architecture of context-aware proof-tools.
  2076 
  2077 * Method "ferrack" implements quantifier elimination over
  2078 special-purpose dense linear orders using locales (analogous to
  2079 "algebra"). The method is already installed for class
  2080 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2081 rat, etc.
  2082 
  2083 * Former constant "List.op @" now named "List.append".  Use ML
  2084 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2085 circumvent possible incompatibilities when working on ML level.
  2086 
  2087 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2088 
  2089 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2090 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2091 
  2092 * New syntax for Haskell-like list comprehension (input only), eg.
  2093 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2094 
  2095 * The special syntax for function "filter" has changed from [x :
  2096 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2097 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2098 
  2099 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2100 defined on nat only, as an abbreviation for [a..<Suc b]
  2101 INCOMPATIBILITY.
  2102 
  2103 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2104 
  2105 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2106 
  2107 * New lemma collection field_simps (an extension of ring_simps) for
  2108 manipulating (in)equations involving division. Multiplies with all
  2109 denominators that can be proved to be non-zero (in equations) or
  2110 positive/negative (in inequations).
  2111 
  2112 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2113 have been improved and renamed to ring_simps, group_simps and
  2114 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2115 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2116 
  2117 * Theory Library/Commutative_Ring: switched from recdef to function
  2118 package; constants add, mul, pow now curried.  Infix syntax for
  2119 algebraic operations.
  2120 
  2121 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2122 INCOMPATIBILITY.
  2123 
  2124 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2125 INCOMPATIBILITY.
  2126 
  2127 * HOL/records: generalised field-update to take a function on the
  2128 field rather than the new value: r(|A := x|) is translated to A_update
  2129 (K x) r The K-combinator that is internally used is called K_record.
  2130 INCOMPATIBILITY: Usage of the plain update functions has to be
  2131 adapted.
  2132  
  2133 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2134 * x = 0, which are required for a semiring.  Richer structures do not
  2135 inherit from semiring_0 anymore, because this property is a theorem
  2136 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2137 there is more to prove, but this is mostly trivial.
  2138 
  2139 * Class "recpower" is generalized to arbitrary monoids, not just
  2140 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2141 commutativity or semiring properties additionally.
  2142 
  2143 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2144 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2145 better use 'abbreviation'.
  2146 
  2147 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2148 
  2149 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2150 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2151 significant changes for setting up numeral syntax for types:
  2152   - New constants Numeral.pred and Numeral.succ instead
  2153       of former Numeral.bin_pred and Numeral.bin_succ.
  2154   - Use integer operations instead of bin_add, bin_mult and so on.
  2155   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2156   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2157 
  2158 See src/HOL/Integ/IntArith.thy for an example setup.
  2159 
  2160 * Command 'normal_form' computes the normal form of a term that may
  2161 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2162 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2163 heavy-duty computations because the functions are compiled to ML
  2164 first.  Correspondingly, a method "normalization" is provided.  See
  2165 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2166 
  2167 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2168 25 like -->); output depends on the "iff" print_mode, the default is
  2169 "A = B" (with priority 50).
  2170 
  2171 * Relations less (<) and less_eq (<=) are also available on type bool.
  2172 Modified syntax to disallow nesting without explicit parentheses,
  2173 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2174 INCOMPATIBILITY.
  2175 
  2176 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2177 
  2178 * Relation composition operator "op O" now has precedence 75 and binds
  2179 stronger than union and intersection. INCOMPATIBILITY.
  2180 
  2181 * The old set interval syntax "{m..n(}" (and relatives) has been
  2182 removed.  Use "{m..<n}" (and relatives) instead.
  2183 
  2184 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2185 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2186 ``declare [[simproc del: neq]]''.
  2187 
  2188 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2189 True/False.
  2190 
  2191 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2192 
  2193 * Theorem setsum_mult renamed to setsum_right_distrib.
  2194 
  2195 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2196 ``rule'' method.
  2197 
  2198 * Reimplemented methods "sat" and "satx", with several improvements:
  2199 goals no longer need to be stated as "<prems> ==> False", equivalences
  2200 (i.e. "=" on type bool) are handled, variable names of the form
  2201 "lit_<n>" are no longer reserved, significant speedup.
  2202 
  2203 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2204 zChaff is still supported as well.
  2205 
  2206 * 'inductive' and 'datatype': provide projections of mutual rules,
  2207 bundled as foo_bar.inducts;
  2208 
  2209 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2210 Library.
  2211 
  2212 * Library: moved theory Accessible_Part to main HOL.
  2213 
  2214 * Library: added theory Coinductive_List of potentially infinite lists
  2215 as greatest fixed-point.
  2216 
  2217 * Library: added theory AssocList which implements (finite) maps as
  2218 association lists.
  2219 
  2220 * Method "evaluation" solves goals (i.e. a boolean expression)
  2221 efficiently by compiling it to ML.  The goal is "proved" (via an
  2222 oracle) if it evaluates to True.
  2223 
  2224 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2225 also when invoked by the simplifier.  This results in the Simplifier
  2226 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2227 Configuration option fast_arith_split_limit=0 recovers the old
  2228 behavior.
  2229 
  2230 * Support for hex (0x20) and binary (0b1001) numerals.
  2231 
  2232 * New method: reify eqs (t), where eqs are equations for an
  2233 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2234 parameter, computes a term s::'b and a list xs::'a list and proves the
  2235 theorem I xs s = t. This is also known as reification or quoting. The
  2236 resulting theorem is applied to the subgoal to substitute t with I xs
  2237 s.  If t is omitted, the subgoal itself is reified.
  2238 
  2239 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2240 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2241 where f is supposed to be a computable function (in the sense of code
  2242 generattion). The method uses reify to compute s and xs as above then
  2243 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2244 r and finally gets the theorem t = r, which is again applied to the
  2245 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2246 
  2247 * Reflection: Automatic reification now handels binding, an example is
  2248 available in src/HOL/ex/ReflectionEx.thy
  2249 
  2250 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2251 command 'statespace' that is similar to 'record', but introduces an
  2252 abstract specification based on the locale infrastructure instead of
  2253 HOL types.  This leads to extra flexibility in composing state spaces,
  2254 in particular multiple inheritance and renaming of components.
  2255 
  2256 
  2257 *** HOL-Complex ***
  2258 
  2259 * Hyperreal: Functions root and sqrt are now defined on negative real
  2260 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2261 Nonnegativity side conditions have been removed from many lemmas, so
  2262 that more subgoals may now be solved by simplification; potential
  2263 INCOMPATIBILITY.
  2264 
  2265 * Real: new type classes formalize real normed vector spaces and
  2266 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2267 and norm :: 'a => real.
  2268 
  2269 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2270 reals into other types. The overloaded constant Reals :: 'a set is now
  2271 defined as range of_real; potential INCOMPATIBILITY.
  2272 
  2273 * Real: proper support for ML code generation, including 'quickcheck'.
  2274 Reals are implemented as arbitrary precision rationals.
  2275 
  2276 * Hyperreal: Several constants that previously worked only for the
  2277 reals have been generalized, so they now work over arbitrary vector
  2278 spaces. Type annotations may need to be added in some cases; potential
  2279 INCOMPATIBILITY.
  2280 
  2281   Infinitesimal  :: ('a::real_normed_vector) star set
  2282   HFinite        :: ('a::real_normed_vector) star set
  2283   HInfinite      :: ('a::real_normed_vector) star set
  2284   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2285   monad          :: ('a::real_normed_vector) star => 'a star set
  2286   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2287   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2288   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2289   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2290   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2291   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2292   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2293   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2294   sgn            :: 'a::real_normed_vector => 'a
  2295   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2296 
  2297 * Complex: Some complex-specific constants are now abbreviations for
  2298 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2299 hnorm.  Other constants have been entirely removed in favor of the
  2300 polymorphic versions (INCOMPATIBILITY):
  2301 
  2302   approx        <-- capprox
  2303   HFinite       <-- CFinite
  2304   HInfinite     <-- CInfinite
  2305   Infinitesimal <-- CInfinitesimal
  2306   monad         <-- cmonad
  2307   galaxy        <-- cgalaxy
  2308   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2309   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2310   (ns)deriv     <-- (ns)cderiv
  2311 
  2312 
  2313 *** HOL-Algebra ***
  2314 
  2315 * Formalisation of ideals and the quotient construction over rings.
  2316 
  2317 * Order and lattice theory no longer based on records.
  2318 INCOMPATIBILITY.
  2319 
  2320 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2321 greatest_closed.  INCOMPATIBILITY.
  2322 
  2323 * Method algebra is now set up via an attribute.  For examples see
  2324 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2325 of algebraic structures.
  2326 
  2327 * Renamed theory CRing to Ring.
  2328 
  2329 
  2330 *** HOL-Nominal ***
  2331 
  2332 * Substantial, yet incomplete support for nominal datatypes (binding
  2333 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2334 src/HOL/Nominal/Examples.  Prospective users should consult
  2335 http://isabelle.in.tum.de/nominal/
  2336 
  2337 
  2338 *** ML ***
  2339 
  2340 * ML basics: just one true type int, which coincides with IntInf.int
  2341 (even on SML/NJ).
  2342 
  2343 * ML within Isar: antiquotations allow to embed statically-checked
  2344 formal entities in the source, referring to the context available at
  2345 compile-time.  For example:
  2346 
  2347 ML {* @{sort "{zero,one}"} *}
  2348 ML {* @{typ "'a => 'b"} *}
  2349 ML {* @{term "%x. x"} *}
  2350 ML {* @{prop "x == y"} *}
  2351 ML {* @{ctyp "'a => 'b"} *}
  2352 ML {* @{cterm "%x. x"} *}
  2353 ML {* @{cprop "x == y"} *}
  2354 ML {* @{thm asm_rl} *}
  2355 ML {* @{thms asm_rl} *}
  2356 ML {* @{type_name c} *}
  2357 ML {* @{type_syntax c} *}
  2358 ML {* @{const_name c} *}
  2359 ML {* @{const_syntax c} *}
  2360 ML {* @{context} *}
  2361 ML {* @{theory} *}
  2362 ML {* @{theory Pure} *}
  2363 ML {* @{theory_ref} *}
  2364 ML {* @{theory_ref Pure} *}
  2365 ML {* @{simpset} *}
  2366 ML {* @{claset} *}
  2367 ML {* @{clasimpset} *}
  2368 
  2369 The same works for sources being ``used'' within an Isar context.
  2370 
  2371 * ML in Isar: improved error reporting; extra verbosity with
  2372 ML_Context.trace enabled.
  2373 
  2374 * Pure/General/table.ML: the join operations now works via exceptions
  2375 DUP/SAME instead of type option. This is simpler in simple cases, and
  2376 admits slightly more efficient complex applications.
  2377 
  2378 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2379 use Context.generic instead of just theory.
  2380 
  2381 * Pure: datatype Context.generic joins theory/Proof.context and
  2382 provides some facilities for code that works in either kind of
  2383 context, notably GenericDataFun for uniform theory and proof data.
  2384 
  2385 * Pure: simplified internal attribute type, which is now always
  2386 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2387 local (Proof.context) attributes have been discontinued, while
  2388 minimizing code duplication. Thm.rule_attribute and
  2389 Thm.declaration_attribute build canonical attributes; see also structure
  2390 Context for further operations on Context.generic, notably
  2391 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2392 declarations and definitions.
  2393 
  2394 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2395 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2396 init only required for impure data. INCOMPATIBILITY: empty really need
  2397 to be empty (no dependencies on theory content!)
  2398 
  2399 * Pure/kernel: consts certification ignores sort constraints given in
  2400 signature declarations. (This information is not relevant to the
  2401 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2402 potential INCOMPATIBILITY.
  2403 
  2404 * Pure: axiomatic type classes are now purely definitional, with
  2405 explicit proofs of class axioms and super class relations performed
  2406 internally. See Pure/axclass.ML for the main internal interfaces --
  2407 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2408 AxClass.axiomatize_class/classrel/arity supersede
  2409 Sign.add_classes/classrel/arities.
  2410 
  2411 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2412 global/local versions on theory vs. Proof.context have been
  2413 discontinued; Attrib.syntax and Method.syntax have been adapted
  2414 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2415 attributes, methods, etc.
  2416 
  2417 * Pure: several functions of signature "... -> theory -> theory * ..."
  2418 have been reoriented to "... -> theory -> ... * theory" in order to
  2419 allow natural usage in combination with the ||>, ||>>, |-> and
  2420 fold_map combinators.
  2421 
  2422 * Pure: official theorem names (closed derivations) and additional
  2423 comments (tags) are now strictly separate.  Name hints -- which are
  2424 maintained as tags -- may be attached any time without affecting the
  2425 derivation.
  2426 
  2427 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2428 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2429 achieve the old behaviour.
  2430 
  2431 * Pure: the "Goal" constant is now called "prop", supporting a
  2432 slightly more general idea of ``protecting'' meta-level rule
  2433 statements.
  2434 
  2435 * Pure: Logic.(un)varify only works in a global context, which is now
  2436 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2437 Logic.legacy_(un)varify as temporary workaround.
  2438 
  2439 * Pure: structure Name provides scalable operations for generating
  2440 internal variable names, notably Name.variants etc.  This replaces
  2441 some popular functions from term.ML:
  2442 
  2443   Term.variant		->  Name.variant
  2444   Term.variantlist	->  Name.variant_list
  2445   Term.invent_names	->  Name.invent_list
  2446 
  2447 Note that low-level renaming rarely occurs in new code -- operations
  2448 from structure Variable are used instead (see below).
  2449 
  2450 * Pure: structure Variable provides fundamental operations for proper
  2451 treatment of fixed/schematic variables in a context.  For example,
  2452 Variable.import introduces fixes for schematics of given facts and
  2453 Variable.export reverses the effect (up to renaming) -- this replaces
  2454 various freeze_thaw operations.
  2455 
  2456 * Pure: structure Goal provides simple interfaces for
  2457 init/conclude/finish and tactical prove operations (replacing former
  2458 Tactic.prove).  Goal.prove is the canonical way to prove results
  2459 within a given context; Goal.prove_global is a degraded version for
  2460 theory level goals, including a global Drule.standard.  Note that
  2461 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2462 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2463 in a locale context).
  2464 
  2465 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2466 and type checking (Syntax.check_term etc.), with common combinations
  2467 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2468 which are considered legacy and await removal.
  2469 
  2470 * Pure/Syntax: generic interfaces for type unchecking
  2471 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2472 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2473 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2474 available for convenience, but refer to the very same operations using
  2475 a mere theory instead of a full context.
  2476 
  2477 * Isar: simplified treatment of user-level errors, using exception
  2478 ERROR of string uniformly.  Function error now merely raises ERROR,
  2479 without any side effect on output channels.  The Isar toplevel takes
  2480 care of proper display of ERROR exceptions.  ML code may use plain
  2481 handle/can/try; cat_error may be used to concatenate errors like this:
  2482 
  2483   ... handle ERROR msg => cat_error msg "..."
  2484 
  2485 Toplevel ML code (run directly or through the Isar toplevel) may be
  2486 embedded into the Isar toplevel with exception display/debug like
  2487 this:
  2488 
  2489   Isar.toplevel (fn () => ...)
  2490 
  2491 INCOMPATIBILITY, removed special transform_error facilities, removed
  2492 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2493 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2494 -- use plain ERROR instead.
  2495 
  2496 * Isar: theory setup now has type (theory -> theory), instead of a
  2497 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2498 
  2499 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2500 ProofContext.debug/verbose flags.
  2501 
  2502 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2503 theory before entering a proof state.  Transactions now always see a
  2504 quasi-functional intermediate checkpoint, both in interactive and
  2505 batch mode.
  2506 
  2507 * Isar: simplified interfaces for outer syntax.  Renamed
  2508 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2509 OuterSyntax.add_parsers -- this functionality is now included in
  2510 OuterSyntax.command etc.  INCOMPATIBILITY.
  2511 
  2512 * Simplifier: the simpset of a running simplification process now
  2513 contains a proof context (cf. Simplifier.the_context), which is the
  2514 very context that the initial simpset has been retrieved from (by
  2515 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2516 (solver, looper etc.) may depend on arbitrary proof data.
  2517 
  2518 * Simplifier.inherit_context inherits the proof context (plus the
  2519 local bounds) of the current simplification process; any simproc
  2520 etc. that calls the Simplifier recursively should do this!  Removed
  2521 former Simplifier.inherit_bounds, which is already included here --
  2522 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2523 specify an explicit context using Simplifier.context/theory_context.
  2524 
  2525 * Simplifier/Classical Reasoner: more abstract interfaces
  2526 change_simpset/claset for modifying the simpset/claset reference of a
  2527 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2528 INCOMPATIBILITY.
  2529 
  2530 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2531 "Trueprop" etc.
  2532 
  2533 
  2534 *** System ***
  2535 
  2536 * settings: the default heap location within ISABELLE_HOME_USER now
  2537 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2538 Isabelle installations.
  2539 
  2540 * isabelle-process: option -S (secure mode) disables some critical
  2541 operations, notably runtime compilation and evaluation of ML source
  2542 code.
  2543 
  2544 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2545 
  2546 * Support for parallel execution, using native multicore support of
  2547 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2548 independent theories, according to the given theory header
  2549 specifications. The maximum number of worker threads is specified via
  2550 usedir option -M or the "max-threads" setting in Proof General. A
  2551 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2552 to 6 on a 8-core machine.  User-code needs to observe certain
  2553 guidelines for thread-safe programming, see appendix A in the Isar
  2554 Implementation manual.
  2555 
  2556 
  2557 
  2558 New in Isabelle2005 (October 2005)
  2559 ----------------------------------
  2560 
  2561 *** General ***
  2562 
  2563 * Theory headers: the new header syntax for Isar theories is
  2564 
  2565   theory <name>
  2566   imports <theory1> ... <theoryN>
  2567   uses <file1> ... <fileM>
  2568   begin
  2569 
  2570 where the 'uses' part is optional.  The previous syntax
  2571 
  2572   theory <name> = <theory1> + ... + <theoryN>:
  2573 
  2574 will disappear in the next release.  Use isatool fixheaders to convert
  2575 existing theory files.  Note that there is no change in ancient
  2576 non-Isar theories now, but these will disappear soon.
  2577 
  2578 * Theory loader: parent theories can now also be referred to via
  2579 relative and absolute paths.
  2580 
  2581 * Command 'find_theorems' searches for a list of criteria instead of a
  2582 list of constants. Known criteria are: intro, elim, dest, name:string,
  2583 simp:term, and any term. Criteria can be preceded by '-' to select
  2584 theorems that do not match. Intro, elim, dest select theorems that
  2585 match the current goal, name:s selects theorems whose fully qualified
  2586 name contain s, and simp:term selects all simplification rules whose
  2587 lhs match term.  Any other term is interpreted as pattern and selects
  2588 all theorems matching the pattern. Available in ProofGeneral under
  2589 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2590 
  2591   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2592 
  2593 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2594 matching the current goal as introduction rule and not having "HOL."
  2595 in their name (i.e. not being defined in theory HOL).
  2596 
  2597 * Command 'thms_containing' has been discontinued in favour of
  2598 'find_theorems'; INCOMPATIBILITY.
  2599 
  2600 * Communication with Proof General is now 8bit clean, which means that
  2601 Unicode text in UTF-8 encoding may be used within theory texts (both
  2602 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2603 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2604 
  2605   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2606   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2607 
  2608 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2609 Classical Reasoner.  Typical big applications run around 2 times
  2610 faster.
  2611 
  2612 
  2613 *** Document preparation ***
  2614 
  2615 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2616 of raw sources.  Only those symbols that do not require additional
  2617 LaTeX packages (depending on comments in isabellesym.sty) are
  2618 displayed properly, everything else is left verbatim.  isatool display
  2619 and isatool print are used as front ends (these are subject to the
  2620 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2621 
  2622 * Command tags control specific markup of certain regions of text,
  2623 notably folding and hiding.  Predefined tags include "theory" (for
  2624 theory begin and end), "proof" for proof commands, and "ML" for
  2625 commands involving ML code; the additional tags "visible" and
  2626 "invisible" are unused by default.  Users may give explicit tag
  2627 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2628 interpretation of tags is determined by the LaTeX job during document
  2629 preparation: see option -V of isatool usedir, or options -n and -t of
  2630 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2631 \isadroptag.
  2632 
  2633 Several document versions may be produced at the same time via isatool
  2634 usedir (the generated index.html will link all of them).  Typical
  2635 specifications include ''-V document=theory,proof,ML'' to present
  2636 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2637 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2638 these parts without any formal replacement text.  The Isabelle site
  2639 default settings produce ''document'' and ''outline'' versions as
  2640 specified above.
  2641 
  2642 * Several new antiquotations:
  2643 
  2644   @{term_type term} prints a term with its type annotated;
  2645 
  2646   @{typeof term} prints the type of a term;
  2647 
  2648   @{const const} is the same as @{term const}, but checks that the
  2649   argument is a known logical constant;
  2650 
  2651   @{term_style style term} and @{thm_style style thm} print a term or
  2652   theorem applying a "style" to it
  2653 
  2654   @{ML text}
  2655 
  2656 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2657 definitions, equations, inequations etc., 'concl' printing only the
  2658 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2659 to print the specified premise.  TermStyle.add_style provides an ML
  2660 interface for introducing further styles.  See also the "LaTeX Sugar"
  2661 document practical applications.  The ML antiquotation prints
  2662 type-checked ML expressions verbatim.
  2663 
  2664 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2665 and 'text' support optional locale specification '(in loc)', which
  2666 specifies the default context for interpreting antiquotations.  For
  2667 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2668 
  2669 * Option 'locale=NAME' of antiquotations specifies an alternative
  2670 context interpreting the subsequent argument.  For example: @{thm
  2671 [locale=lattice] inf_assoc}.
  2672 
  2673 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2674 a proof context.
  2675 
  2676 * Proper output of antiquotations for theory commands involving a
  2677 proof context (such as 'locale' or 'theorem (in loc) ...').
  2678 
  2679 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2680 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2681 
  2682 * isatool usedir: new option -C (default true) controls whether option
  2683 -D should include a copy of the original document directory; -C false
  2684 prevents unwanted effects such as copying of administrative CVS data.
  2685 
  2686 
  2687 *** Pure ***
  2688 
  2689 * Considerably improved version of 'constdefs' command.  Now performs
  2690 automatic type-inference of declared constants; additional support for
  2691 local structure declarations (cf. locales and HOL records), see also
  2692 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2693 sequential dependencies of definitions within a single 'constdefs'
  2694 section; moreover, the declared name needs to be an identifier.  If
  2695 all fails, consider to fall back on 'consts' and 'defs' separately.
  2696 
  2697 * Improved indexed syntax and implicit structures.  First of all,
  2698 indexed syntax provides a notational device for subscripted
  2699 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2700 expressions.  Secondly, in a local context with structure
  2701 declarations, number indexes \<^sub>n or the empty index (default
  2702 number 1) refer to a certain fixed variable implicitly; option
  2703 show_structs controls printing of implicit structures.  Typical
  2704 applications of these concepts involve record types and locales.
  2705 
  2706 * New command 'no_syntax' removes grammar declarations (and
  2707 translations) resulting from the given syntax specification, which is
  2708 interpreted in the same manner as for the 'syntax' command.
  2709 
  2710 * 'Advanced' translation functions (parse_translation etc.) may depend
  2711 on the signature of the theory context being presently used for
  2712 parsing/printing, see also isar-ref manual.
  2713 
  2714 * Improved 'oracle' command provides a type-safe interface to turn an
  2715 ML expression of type theory -> T -> term into a primitive rule of
  2716 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2717 is already included here); see also FOL/ex/IffExample.thy;
  2718 INCOMPATIBILITY.
  2719 
  2720 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2721 before); "cI" is no longer bound, use "c.intro" instead.
  2722 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2723 axclasses vs. locales.
  2724 
  2725 * Improved internal renaming of symbolic identifiers -- attach primes
  2726 instead of base 26 numbers.
  2727 
  2728 * New flag show_question_marks controls printing of leading question
  2729 marks in schematic variable names.
  2730 
  2731 * In schematic variable names, *any* symbol following \<^isub> or
  2732 \<^isup> is now treated as part of the base name.  For example, the
  2733 following works without printing of awkward ".0" indexes:
  2734 
  2735   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2736     by simp
  2737 
  2738 * Inner syntax includes (*(*nested*) comments*).
  2739 
  2740 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2741 annotations as "(00...)".
  2742 
  2743 * Clear separation of logical types and nonterminals, where the latter
  2744 may only occur in 'syntax' specifications or type abbreviations.
  2745 Before that distinction was only partially implemented via type class
  2746 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2747 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2748 exotic syntax specifications may require further adaption
  2749 (e.g. Cube/Cube.thy).
  2750 
  2751 * Removed obsolete type class "logic", use the top sort {} instead.
  2752 Note that non-logical types should be declared as 'nonterminals'
  2753 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2754 specifications.
  2755 
  2756 * Attributes 'induct' and 'cases': type or set names may now be
  2757 locally fixed variables as well.
  2758 
  2759 * Simplifier: can now control the depth to which conditional rewriting
  2760 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2761 Limit.
  2762 
  2763 * Simplifier: simplification procedures may now take the current
  2764 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2765 interface), which is very useful for calling the Simplifier
  2766 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2767 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2768 low-level mk_simproc no longer applies Logic.varify internally, to
  2769 allow for use in a context of fixed variables.
  2770 
  2771 * thin_tac now works even if the assumption being deleted contains !!
  2772 or ==>.  More generally, erule now works even if the major premise of
  2773 the elimination rule contains !! or ==>.
  2774 
  2775 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2776 
  2777 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2778 from Pure, which contains all common declarations already.  Both
  2779 theories are defined via plain Isabelle/Isar .thy files.
  2780 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2781 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2782 use isatool fixcpure to adapt your theory and ML sources.
  2783 
  2784 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2785 selections of theorems in named facts via index ranges.
  2786 
  2787 * 'print_theorems': in theory mode, really print the difference
  2788 wrt. the last state (works for interactive theory development only),
  2789 in proof mode print all local facts (cf. 'print_facts');
  2790 
  2791 * 'hide': option '(open)' hides only base names.
  2792 
  2793 * More efficient treatment of intermediate checkpoints in interactive
  2794 theory development.
  2795 
  2796 * Code generator is now invoked via code_module (incremental code
  2797 generation) and code_library (modular code generation, ML structures
  2798 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2799 must be quoted when used as identifiers.
  2800 
  2801 * New 'value' command for reading, evaluating and printing terms using
  2802 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2803 quoted when used as identifier.
  2804 
  2805 
  2806 *** Locales ***
  2807 
  2808 * New commands for the interpretation of locale expressions in
  2809 theories (1), locales (2) and proof contexts (3).  These generate
  2810 proof obligations from the expression specification.  After the
  2811 obligations have been discharged, theorems of the expression are added
  2812 to the theory, target locale or proof context.  The synopsis of the
  2813 commands is a follows:
  2814 
  2815   (1) interpretation expr inst
  2816   (2) interpretation target < expr
  2817   (3) interpret expr inst
  2818 
  2819 Interpretation in theories and proof contexts require a parameter
  2820 instantiation of terms from the current context.  This is applied to
  2821 specifications and theorems of the interpreted expression.
  2822 Interpretation in locales only permits parameter renaming through the
  2823 locale expression.  Interpretation is smart in that interpretations
  2824 that are active already do not occur in proof obligations, neither are
  2825 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2826 inspect active interpretations of a particular locale.  For details,
  2827 see the Isar Reference manual.  Examples can be found in
  2828 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2829 
  2830 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2831 'interpret' instead.
  2832 
  2833 * New context element 'constrains' for adding type constraints to
  2834 parameters.
  2835 
  2836 * Context expressions: renaming of parameters with syntax
  2837 redeclaration.
  2838 
  2839 * Locale declaration: 'includes' disallowed.
  2840 
  2841 * Proper static binding of attribute syntax -- i.e. types / terms /
  2842 facts mentioned as arguments are always those of the locale definition
  2843 context, independently of the context of later invocations.  Moreover,
  2844 locale operations (renaming and type / term instantiation) are applied
  2845 to attribute arguments as expected.
  2846 
  2847 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2848 actual attributes; rare situations may require Attrib.attribute to
  2849 embed those attributes into Attrib.src that lack concrete syntax.
  2850 Attribute implementations need to cooperate properly with the static
  2851 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2852 Attrib.XXX_thm etc. already do the right thing without further
  2853 intervention.  Only unusual applications -- such as "where" or "of"
  2854 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2855 on the context and the facts involved -- may have to assign parsed
  2856 values to argument tokens explicitly.
  2857 
  2858 * Changed parameter management in theorem generation for long goal
  2859 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2860 theorem statement in rare situations.
  2861 
  2862 * Locale inspection command 'print_locale' omits notes elements.  Use
  2863 'print_locale!' to have them included in the output.
  2864 
  2865 
  2866 *** Provers ***
  2867 
  2868 * Provers/hypsubst.ML: improved version of the subst method, for
  2869 single-step rewriting: it now works in bound variable contexts. New is
  2870 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2871 rewrite a different subterm than the original subst method, which is
  2872 still available as 'simplesubst'.
  2873 
  2874 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2875 and quasi orders.
  2876 
  2877 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2878 reflexive-transitive closure of relations.
  2879 
  2880 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2881 limit (previously hard-coded with a value of 20) user-definable.
  2882 
  2883 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2884 is peformed already.  Object-logics merely need to finish their
  2885 initial simpset configuration as before.  INCOMPATIBILITY.
  2886 
  2887 
  2888 *** HOL ***
  2889 
  2890 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2891 
  2892   syntax (epsilon)
  2893     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2894 
  2895 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2896 and x-symbol; use option '-m epsilon' to get it actually printed.
  2897 Moreover, the mathematically important symbolic identifier \<epsilon>
  2898 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2899 
  2900 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2901 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2902 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2903 support corresponding Isar calculations.
  2904 
  2905 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2906 instead of ":".
  2907 
  2908 * theory SetInterval: changed the syntax for open intervals:
  2909 
  2910   Old       New
  2911   {..n(}    {..<n}
  2912   {)n..}    {n<..}
  2913   {m..n(}   {m..<n}
  2914   {)m..n}   {m<..n}
  2915   {)m..n(}  {m<..<n}
  2916 
  2917 The old syntax is still supported but will disappear in the next
  2918 release.  For conversion use the following Emacs search and replace
  2919 patterns (these are not perfect but work quite well):
  2920 
  2921   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2922   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2923 
  2924 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2925 equalities in commutative rings; method 'algebra' provides a generic
  2926 interface.
  2927 
  2928 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2929 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2930 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2931 be a tuple pattern.
  2932 
  2933 Some new syntax forms are available:
  2934 
  2935   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2936   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2937   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2938   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2939 
  2940 The latter form "\<Sum>x < k. e" used to be based on a separate
  2941 function "Summation", which has been discontinued.
  2942 
  2943 * theory Finite_Set: in structured induction proofs, the insert case
  2944 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2945 (insert F x)'.
  2946 
  2947 * The 'refute' command has been extended to support a much larger
  2948 fragment of HOL, including axiomatic type classes, constdefs and
  2949 typedefs, inductive datatypes and recursion.
  2950 
  2951 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2952 Requires zChaff with proof generation to be installed.  See
  2953 HOL/ex/SAT_Examples.thy for examples.
  2954 
  2955 * Datatype induction via method 'induct' now preserves the name of the
  2956 induction variable. For example, when proving P(xs::'a list) by
  2957 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2958 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2959 in unstructured proof scripts.
  2960 
  2961 * Reworked implementation of records.  Improved scalability for
  2962 records with many fields, avoiding performance problems for type
  2963 inference. Records are no longer composed of nested field types, but
  2964 of nested extension types. Therefore the record type only grows linear
  2965 in the number of extensions and not in the number of fields.  The
  2966 top-level (users) view on records is preserved.  Potential
  2967 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2968 old record representation. The type generated for a record is called
  2969 <record_name>_ext_type.
  2970 
  2971 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2972 proofs triggered by a record definition or a simproc (if
  2973 quick_and_dirty is enabled).  Definitions of large records can take
  2974 quite long.
  2975 
  2976 New simproc record_upd_simproc for simplification of multiple record
  2977 updates enabled by default.  Moreover, trivial updates are also
  2978 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2979 occasionally, since simplification is more powerful by default.
  2980 
  2981 * typedef: proper support for polymorphic sets, which contain extra
  2982 type-variables in the term.
  2983 
  2984 * Simplifier: automatically reasons about transitivity chains
  2985 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2986 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2987 old proofs break occasionally as simplification may now solve more
  2988 goals than previously.
  2989 
  2990 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2991 present.  Works for all partial orders (class "order"), in particular
  2992 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2993 just like y <= x.
  2994 
  2995 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2996 bound variable or a constant then the let is unfolded.  Otherwise
  2997 first a is simplified to b, and then f b is simplified to g. If
  2998 possible we abstract b from g arriving at "let x = b in h x",
  2999 otherwise we unfold the let and arrive at g.  The simproc can be
  3000 enabled/disabled by the reference use_let_simproc.  Potential
  3001 INCOMPATIBILITY since simplification is more powerful by default.
  3002 
  3003 * Classical reasoning: the meson method now accepts theorems as arguments.
  3004 
  3005 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3006 jobs to provide advice on the provability of subgoals.
  3007 
  3008 * Theory OrderedGroup and Ring_and_Field: various additions and
  3009 improvements to faciliate calculations involving equalities and
  3010 inequalities.
  3011 
  3012 The following theorems have been eliminated or modified
  3013 (INCOMPATIBILITY):
  3014 
  3015   abs_eq             now named abs_of_nonneg
  3016   abs_of_ge_0        now named abs_of_nonneg
  3017   abs_minus_eq       now named abs_of_nonpos
  3018   imp_abs_id         now named abs_of_nonneg
  3019   imp_abs_neg_id     now named abs_of_nonpos
  3020   mult_pos           now named mult_pos_pos
  3021   mult_pos_le        now named mult_nonneg_nonneg
  3022   mult_pos_neg_le    now named mult_nonneg_nonpos
  3023   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3024   mult_neg           now named mult_neg_neg
  3025   mult_neg_le        now named mult_nonpos_nonpos
  3026 
  3027 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3028      
  3029      zero_le_square
  3030      not_square_less_zero 
  3031 
  3032   The following lemmas have been deleted from Real/RealPow:
  3033   
  3034      realpow_zero_zero
  3035      realpow_two
  3036      realpow_less
  3037      zero_le_power
  3038      realpow_two_le
  3039      abs_realpow_two
  3040      realpow_two_abs     
  3041 
  3042 * Theory Parity: added rules for simplifying exponents.
  3043 
  3044 * Theory List:
  3045 
  3046 The following theorems have been eliminated or modified
  3047 (INCOMPATIBILITY):
  3048 
  3049   list_all_Nil       now named list_all.simps(1)
  3050   list_all_Cons      now named list_all.simps(2)
  3051   list_all_conv      now named list_all_iff
  3052   set_mem_eq         now named mem_iff
  3053 
  3054 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3055 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3056 
  3057 
  3058 *** HOL-Complex ***
  3059 
  3060 * Theory RealDef: better support for embedding natural numbers and
  3061 integers in the reals.
  3062 
  3063 The following theorems have been eliminated or modified
  3064 (INCOMPATIBILITY):
  3065 
  3066   exp_ge_add_one_self  now requires no hypotheses
  3067   real_of_int_add      reversed direction of equality (use [symmetric])
  3068   real_of_int_minus    reversed direction of equality (use [symmetric])
  3069   real_of_int_diff     reversed direction of equality (use [symmetric])
  3070   real_of_int_mult     reversed direction of equality (use [symmetric])
  3071 
  3072 * Theory RComplete: expanded support for floor and ceiling functions.
  3073 
  3074 * Theory Ln is new, with properties of the natural logarithm
  3075 
  3076 * Hyperreal: There is a new type constructor "star" for making
  3077 nonstandard types.  The old type names are now type synonyms:
  3078 
  3079   hypreal = real star
  3080   hypnat = nat star
  3081   hcomplex = complex star
  3082 
  3083 * Hyperreal: Many groups of similarly-defined constants have been
  3084 replaced by polymorphic versions (INCOMPATIBILITY):
  3085 
  3086   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3087 
  3088   starset      <-- starsetNat, starsetC
  3089   *s*          <-- *sNat*, *sc*
  3090   starset_n    <-- starsetNat_n, starsetC_n
  3091   *sn*         <-- *sNatn*, *scn*
  3092   InternalSets <-- InternalNatSets, InternalCSets
  3093 
  3094   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3095   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3096   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3097   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3098   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3099 
  3100 * Hyperreal: Many type-specific theorems have been removed in favor of
  3101 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3102 
  3103   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3104   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3105   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3106   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3107   right_minus <-- hypreal_add_minus
  3108   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3109   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3110   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3111   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3112   mult_1_right <-- hcomplex_mult_one_right
  3113   mult_zero_left <-- hcomplex_mult_zero_left
  3114   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3115   right_distrib <-- hypnat_add_mult_distrib2
  3116   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3117   right_inverse <-- hypreal_mult_inverse
  3118   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3119   order_refl <-- {hypreal,hypnat}_le_refl
  3120   order_trans <-- {hypreal,hypnat}_le_trans
  3121   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3122   order_less_le <-- {hypreal,hypnat}_less_le
  3123   linorder_linear <-- {hypreal,hypnat}_le_linear
  3124   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3125   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3126   add_nonneg_nonneg <-- hypreal_le_add_order
  3127 
  3128 * Hyperreal: Separate theorems having to do with type-specific
  3129 versions of constants have been merged into theorems that apply to the
  3130 new polymorphic constants (INCOMPATIBILITY):
  3131 
  3132   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3133   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3134   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3135   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3136   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3137   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3138   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3139   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3140   STAR_diff <-- {STAR,STARC}_diff
  3141   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3142     STARC_hcomplex_of_complex}_image_subset
  3143   starset_n_Un <-- starset{Nat,C}_n_Un
  3144   starset_n_Int <-- starset{Nat,C}_n_Int
  3145   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3146   starset_n_diff <-- starset{Nat,C}_n_diff
  3147   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3148   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3149   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3150   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3151   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3152   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3153   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3154   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3155   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3156   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3157   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3158   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3159   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3160   starfun_diff <-- starfun{C,RC,CR}_diff
  3161   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3162   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3163   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3164   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3165   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3166   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3167   starfun_Id <-- starfunC_Id
  3168   starfun_approx <-- starfun{Nat,CR}_approx
  3169   starfun_capprox <-- starfun{C,RC}_capprox
  3170   starfun_abs <-- starfunNat_rabs
  3171   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3172   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3173   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3174   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3175   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3176   starfun_add_approx <-- starfunCR_add_approx
  3177   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3178   starfun_divide <-- starfun{C,CR,RC}_divide
  3179   starfun_n <-- starfun{Nat,C}_n
  3180   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3181   starfun_n_add <-- starfun{Nat,C}_n_add
  3182   starfun_n_add_minus <-- starfunNat_n_add_minus
  3183   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3184   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3185   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3186 
  3187   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3188   star_n_minus <-- {hypreal,hcomplex}_minus
  3189   star_n_diff <-- {hypreal,hcomplex}_diff
  3190   star_n_mult <-- {hypreal,hcomplex}_mult
  3191   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3192   star_n_le <-- {hypreal,hypnat}_le
  3193   star_n_less <-- {hypreal,hypnat}_less
  3194   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3195   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3196   star_n_abs <-- hypreal_hrabs
  3197   star_n_divide <-- hcomplex_divide
  3198 
  3199   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3200   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3201   star_of_diff <-- hypreal_of_real_diff
  3202   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3203   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3204   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3205   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3206   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3207   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3208   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3209   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3210   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3211   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3212   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3213   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3214   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3215   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3216   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3217   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3218   star_of_power <-- hypreal_of_real_power
  3219   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3220 
  3221 * Hyperreal: new method "transfer" that implements the transfer
  3222 principle of nonstandard analysis. With a subgoal that mentions
  3223 nonstandard types like "'a star", the command "apply transfer"
  3224 replaces it with an equivalent one that mentions only standard types.
  3225 To be successful, all free variables must have standard types; non-
  3226 standard variables must have explicit universal quantifiers.
  3227 
  3228 * Hyperreal: A theory of Taylor series.
  3229 
  3230 
  3231 *** HOLCF ***
  3232 
  3233 * Discontinued special version of 'constdefs' (which used to support
  3234 continuous functions) in favor of the general Pure one with full
  3235 type-inference.
  3236 
  3237 * New simplification procedure for solving continuity conditions; it
  3238 is much faster on terms with many nested lambda abstractions (cubic
  3239 instead of exponential time).
  3240 
  3241 * New syntax for domain package: selector names are now optional.
  3242 Parentheses should be omitted unless argument is lazy, for example:
  3243 
  3244   domain 'a stream = cons "'a" (lazy "'a stream")
  3245 
  3246 * New command 'fixrec' for defining recursive functions with pattern
  3247 matching; defining multiple functions with mutual recursion is also
  3248 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3249 sinr, or any data constructor defined by the domain package. The given
  3250 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3251 syntax and examples.
  3252 
  3253 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3254 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3255 but the proof obligation additionally includes an admissibility
  3256 requirement. The packages generate instances of class cpo or pcpo,
  3257 with continuity and strictness theorems for Rep and Abs.
  3258 
  3259 * HOLCF: Many theorems have been renamed according to a more standard naming
  3260 scheme (INCOMPATIBILITY):
  3261 
  3262   foo_inject:  "foo$x = foo$y ==> x = y"
  3263   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3264   foo_less:    "(foo$x << foo$y) = (x << y)"
  3265   foo_strict:  "foo$UU = UU"
  3266   foo_defined: "... ==> foo$x ~= UU"
  3267   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3268 
  3269 
  3270 *** ZF ***
  3271 
  3272 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3273 including the First Isomorphism Theorem (on quotienting by the kernel
  3274 of a homomorphism).
  3275 
  3276 * ZF/Simplifier: install second copy of type solver that actually
  3277 makes use of TC rules declared to Isar proof contexts (or locales);
  3278 the old version is still required for ML proof scripts.
  3279 
  3280 
  3281 *** Cube ***
  3282 
  3283 * Converted to Isar theory format; use locales instead of axiomatic
  3284 theories.
  3285 
  3286 
  3287 *** ML ***
  3288 
  3289 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3290 for ||>, ||>>, |>>,
  3291 
  3292 * Pure/library.ML no longer defines its own option datatype, but uses
  3293 that of the SML basis, which has constructors NONE and SOME instead of
  3294 None and Some, as well as exception Option.Option instead of OPTION.
  3295 The functions the, if_none, is_some, is_none have been adapted
  3296 accordingly, while Option.map replaces apsome.
  3297 
  3298 * Pure/library.ML: the exception LIST has been given up in favour of
  3299 the standard exceptions Empty and Subscript, as well as
  3300 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3301 superceded by the standard hd and tl functions etc.
  3302 
  3303 A number of basic list functions are no longer exported to the ML
  3304 toplevel, as they are variants of predefined functions.  The following
  3305 suggests how one can translate existing code:
  3306 
  3307     rev_append xs ys = List.revAppend (xs, ys)
  3308     nth_elem (i, xs) = List.nth (xs, i)
  3309     last_elem xs = List.last xs
  3310     flat xss = List.concat xss
  3311     seq fs = List.app fs
  3312     partition P xs = List.partition P xs
  3313     mapfilter f xs = List.mapPartial f xs
  3314 
  3315 * Pure/library.ML: several combinators for linear functional
  3316 transformations, notably reverse application and composition:
  3317 
  3318   x |> f                f #> g
  3319   (x, y) |-> f          f #-> g
  3320 
  3321 * Pure/library.ML: introduced/changed precedence of infix operators:
  3322 
  3323   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3324   infix 2 ?;
  3325   infix 3 o oo ooo oooo;
  3326   infix 4 ~~ upto downto;
  3327 
  3328 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3329 infix operators.
  3330 
  3331 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3332 fold_map support linear functional transformations and nesting.  For
  3333 example:
  3334 
  3335   fold f [x1, ..., xN] y =
  3336     y |> f x1 |> ... |> f xN
  3337 
  3338   (fold o fold) f [xs1, ..., xsN] y =
  3339     y |> fold f xs1 |> ... |> fold f xsN
  3340 
  3341   fold f [x1, ..., xN] =
  3342     f x1 #> ... #> f xN
  3343 
  3344   (fold o fold) f [xs1, ..., xsN] =
  3345     fold f xs1 #> ... #> fold f xsN
  3346 
  3347 * Pure/library.ML: the following selectors on type 'a option are
  3348 available:
  3349 
  3350   the:               'a option -> 'a  (*partial*)
  3351   these:             'a option -> 'a  where 'a = 'b list
  3352   the_default: 'a -> 'a option -> 'a
  3353   the_list:          'a option -> 'a list
  3354 
  3355 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3356 basic operations for association lists, following natural argument
  3357 order; moreover the explicit equality predicate passed here avoids
  3358 potentially expensive polymorphic runtime equality checks.
  3359 The old functions may be expressed as follows:
  3360 
  3361   assoc = uncurry (AList.lookup (op =))
  3362   assocs = these oo AList.lookup (op =)
  3363   overwrite = uncurry (AList.update (op =)) o swap
  3364 
  3365 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3366 
  3367   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3368   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3369 
  3370 replacing make_keylist and keyfilter (occassionally used)
  3371 Naive rewrites:
  3372 
  3373   make_keylist = AList.make
  3374   keyfilter = AList.find (op =)
  3375 
  3376 * eq_fst and eq_snd now take explicit equality parameter, thus
  3377   avoiding eqtypes. Naive rewrites:
  3378 
  3379     eq_fst = eq_fst (op =)
  3380     eq_snd = eq_snd (op =)
  3381 
  3382 * Removed deprecated apl and apr (rarely used).
  3383   Naive rewrites:
  3384 
  3385     apl (n, op) =>>= curry op n
  3386     apr (op, m) =>>= fn n => op (n, m)
  3387 
  3388 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3389 provides a reasonably efficient light-weight implementation of sets as
  3390 lists.
  3391 
  3392 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3393 few new operations; existing lookup and update are now curried to
  3394 follow natural argument order (for use with fold etc.);
  3395 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3396 
  3397 * Pure/General: output via the Isabelle channels of
  3398 writeln/warning/error etc. is now passed through Output.output, with a
  3399 hook for arbitrary transformations depending on the print_mode
  3400 (cf. Output.add_mode -- the first active mode that provides a output
  3401 function wins).  Already formatted output may be embedded into further
  3402 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3403 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3404 accommodate easy composition of diagnostic messages etc.  Programmers
  3405 rarely need to care about Output.output or Output.raw at all, with
  3406 some notable exceptions: Output.output is required when bypassing the
  3407 standard channels (writeln etc.), or in token translations to produce
  3408 properly formatted results; Output.raw is required when capturing
  3409 already output material that will eventually be presented to the user
  3410 a second time.  For the default print mode, both Output.output and
  3411 Output.raw have no effect.
  3412 
  3413 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3414 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3415 cumulative results are displayed at the end of a batch session.
  3416 
  3417 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3418 replaced by File.platform_path and File.shell_path (with appropriate
  3419 hooks).  This provides a clean interface for unusual systems where the
  3420 internal and external process view of file names are different.
  3421 
  3422 * Pure: more efficient orders for basic syntactic entities: added
  3423 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3424 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3425 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3426 orders now -- potential INCOMPATIBILITY for code that depends on a
  3427 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3428 Library.sort_strings on result).
  3429 
  3430 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3431 fold_types traverse types/terms from left to right, observing natural
  3432 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3433 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3434 
  3435 * Pure: name spaces have been refined, with significant changes of the
  3436 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3437 to extern(_table).  The plain name entry path is superceded by a
  3438 general 'naming' context, which also includes the 'policy' to produce
  3439 a fully qualified name and external accesses of a fully qualified
  3440 name; NameSpace.extend is superceded by context dependent
  3441 Sign.declare_name.  Several theory and proof context operations modify
  3442 the naming context.  Especially note Theory.restore_naming and
  3443 ProofContext.restore_naming to get back to a sane state; note that
  3444 Theory.add_path is no longer sufficient to recover from
  3445 Theory.absolute_path in particular.
  3446 
  3447 * Pure: new flags short_names (default false) and unique_names
  3448 (default true) for controlling output of qualified names.  If
  3449 short_names is set, names are printed unqualified.  If unique_names is
  3450 reset, the name prefix is reduced to the minimum required to achieve
  3451 the original result when interning again, even if there is an overlap
  3452 with earlier declarations.
  3453 
  3454 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3455 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3456 (useful for printing error messages).  INCOMPATIBILITY.
  3457 
  3458 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3459 Theory.theory are now identified, referring to the universal
  3460 Context.theory (see Pure/context.ML).  Actual signature and theory
  3461 content is managed as theory data.  The old code and interfaces were
  3462 spread over many files and structures; the new arrangement introduces
  3463 considerable INCOMPATIBILITY to gain more clarity:
  3464 
  3465   Context -- theory management operations (name, identity, inclusion,
  3466     parents, ancestors, merge, etc.), plus generic theory data;
  3467 
  3468   Sign -- logical signature and syntax operations (declaring consts,
  3469     types, etc.), plus certify/read for common entities;
  3470 
  3471   Theory -- logical theory operations (stating axioms, definitions,
  3472     oracles), plus a copy of logical signature operations (consts,
  3473     types, etc.); also a few basic management operations (Theory.copy,
  3474     Theory.merge, etc.)
  3475 
  3476 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3477 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3478 for convenience -- they merely return the theory.
  3479 
  3480 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3481 
  3482 * Pure: the Isar proof context type is already defined early in Pure
  3483 as Context.proof (note that ProofContext.context and Proof.context are
  3484 aliases, where the latter is the preferred name).  This enables other
  3485 Isabelle components to refer to that type even before Isar is present.
  3486 
  3487 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3488 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3489 any of these kinds.  For example, Sign.intern typeK is now
  3490 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3491 Theory.hide_types.  Also note that former
  3492 Theory.hide_classes/types/consts are now
  3493 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3494 internalize their arguments!  INCOMPATIBILITY.
  3495 
  3496 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3497 datatype thmref (with constructors Name and NameSelection) instead of
  3498 plain string -- INCOMPATIBILITY;
  3499 
  3500 * Pure: cases produced by proof methods specify options, where NONE
  3501 means to remove case bindings -- INCOMPATIBILITY in
  3502 (RAW_)METHOD_CASES.
  3503 
  3504 * Pure: the following operations retrieve axioms or theorems from a
  3505 theory node or theory hierarchy, respectively:
  3506 
  3507   Theory.axioms_of: theory -> (string * term) list
  3508   Theory.all_axioms_of: theory -> (string * term) list
  3509   PureThy.thms_of: theory -> (string * thm) list
  3510   PureThy.all_thms_of: theory -> (string * thm) list
  3511 
  3512 * Pure: print_tac now outputs the goal through the trace channel.
  3513 
  3514 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3515 Reference Toplevel.debug (default false) controls detailed printing
  3516 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3517 controls execution profiling -- set to 1 for time and 2 for space
  3518 (both increase the runtime).
  3519 
  3520 * Isar session: The initial use of ROOT.ML is now always timed,
  3521 i.e. the log will show the actual process times, in contrast to the
  3522 elapsed wall-clock time that the outer shell wrapper produces.
  3523 
  3524 * Simplifier: improved handling of bound variables (nameless
  3525 representation, avoid allocating new strings).  Simprocs that invoke
  3526 the Simplifier recursively should use Simplifier.inherit_bounds to
  3527 avoid local name clashes.  Failure to do so produces warnings
  3528 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3529 for further details.
  3530 
  3531 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3532 bindings for all theorems stored within a given theory; this may help
  3533 in porting non-Isar theories to Isar ones, while keeping ML proof
  3534 scripts for the time being.
  3535 
  3536 * ML operator HTML.with_charset specifies the charset begin used for
  3537 generated HTML files.  For example:
  3538 
  3539   HTML.with_charset "utf-8" use_thy "Hebrew";
  3540   HTML.with_charset "utf-8" use_thy "Chinese";
  3541 
  3542 
  3543 *** System ***
  3544 
  3545 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3546 isabelle, isatool etc.).
  3547 
  3548 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3549 isatool doc, isatool mkdir, display_drafts etc.).
  3550 
  3551 * isatool usedir: option -f allows specification of the ML file to be
  3552 used by Isabelle; default is ROOT.ML.
  3553 
  3554 * New isatool version outputs the version identifier of the Isabelle
  3555 distribution being used.
  3556 
  3557 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3558 (containing Boolean satisfiability problems) into Isabelle/HOL
  3559 theories.
  3560 
  3561 
  3562 
  3563 New in Isabelle2004 (April 2004)
  3564 --------------------------------
  3565 
  3566 *** General ***
  3567 
  3568 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3569   Replaces linorder.ML.
  3570 
  3571 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3572   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3573   (\<a>...\<z>), are now considered normal letters, and can therefore
  3574   be used anywhere where an ASCII letter (a...zA...Z) has until
  3575   now. COMPATIBILITY: This obviously changes the parsing of some
  3576   terms, especially where a symbol has been used as a binder, say
  3577   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3578   as an identifier.  Fix it by inserting a space around former
  3579   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3580   existing theory and ML files.
  3581 
  3582 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3583 
  3584 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3585   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3586   a normal (but invisible) letter. For multiple letter subscripts repeat
  3587   \<^isub> like this: x\<^isub>1\<^isub>2.
  3588 
  3589 * Pure: There are now sub-/superscripts that can span more than one
  3590   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3591   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3592   superscript. The new control characters are not identifier parts.
  3593 
  3594 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3595   content of "..." to the latex file instead of \isacntrl... . The "..."
  3596   may consist of any printable characters excluding the end bracket >.
  3597 
  3598 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3599   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3600   declare constants "final", which prevents their being given a definition
  3601   later.  It is useful for constants whose behaviour is fixed axiomatically
  3602   rather than definitionally, such as the meta-logic connectives.
  3603 
  3604 * Pure: 'instance' now handles general arities with general sorts
  3605   (i.e. intersections of classes),
  3606 
  3607 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3608   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3609   It can be changed to alter the colors/layout of generated pages.
  3610 
  3611 
  3612 *** Isar ***
  3613 
  3614 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3615   cut_tac, subgoal_tac and thin_tac:
  3616   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3617     locales are no longer forced to write Isar proof scripts.
  3618     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3619     emulations.
  3620   - INCOMPATIBILITY: names of variables to be instantiated may no
  3621     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3622     This is consistent with the instantiation attribute "where".
  3623 
  3624 * Attributes "where" and "of":
  3625   - Now take type variables of instantiated theorem into account when reading
  3626     the instantiation string.  This fixes a bug that caused instantiated
  3627     theorems to have too special types in some circumstances.
  3628   - "where" permits explicit instantiations of type variables.
  3629 
  3630 * Calculation commands "moreover" and "also" no longer interfere with
  3631   current facts ("this"), admitting arbitrary combinations with "then"
  3632   and derived forms.
  3633 
  3634 * Locales:
  3635   - Goal statements involving the context element "includes" no longer
  3636     generate theorems with internal delta predicates (those ending on
  3637     "_axioms") in the premise.
  3638     Resolve particular premise with <locale>.intro to obtain old form.
  3639   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3640     specification and "includes" elements in goal statement.
  3641   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3642     [intro?] and [elim?] (respectively) by default.
  3643   - Experimental command for instantiation of locales in proof contexts:
  3644         instantiate <label>[<attrs>]: <loc>
  3645     Instantiates locale <loc> and adds all its theorems to the current context
  3646     taking into account their attributes.  Label and attrs are optional
  3647     modifiers, like in theorem declarations.  If present, names of
  3648     instantiated theorems are qualified with <label>, and the attributes
  3649     <attrs> are applied after any attributes these theorems might have already.
  3650       If the locale has assumptions, a chained fact of the form
  3651     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3652     are derived.  The command does not support old-style locales declared
  3653     with "locale (open)".
  3654       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3655 
  3656 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3657   (Isar) contexts.
  3658 
  3659 
  3660 *** HOL ***
  3661 
  3662 * Proof import: new image HOL4 contains the imported library from
  3663   the HOL4 system with about 2500 theorems. It is imported by
  3664   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3665   can be used like any other Isabelle image.  See
  3666   HOL/Import/HOL/README for more information.
  3667 
  3668 * Simplifier:
  3669   - Much improved handling of linear and partial orders.
  3670     Reasoners for linear and partial orders are set up for type classes
  3671     "linorder" and "order" respectively, and are added to the default simpset
  3672     as solvers.  This means that the simplifier can build transitivity chains
  3673     to solve goals from the assumptions.
  3674   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3675     of blast or auto after simplification become unnecessary because the goal
  3676     is solved by simplification already.
  3677 
  3678 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3679     all proved in axiomatic type classes for semirings, rings and fields.
  3680 
  3681 * Numerics:
  3682   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3683     now formalized using the Ring_and_Field theory mentioned above.
  3684   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3685     than before, because now they are set up once in a generic manner.
  3686   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3687     Look for the general versions in Ring_and_Field (and Power if they concern
  3688     exponentiation).
  3689 
  3690 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3691 
  3692 * Records:
  3693   - Record types are now by default printed with their type abbreviation
  3694     instead of the list of all field types. This can be configured via
  3695     the reference "print_record_type_abbr".
  3696   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3697     (not enabled by default).
  3698   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3699     EX x. x = sel r to True (not enabled by default).
  3700   - Tactic "record_split_simp_tac" to split and simplify records added.
  3701 
  3702 * 'specification' command added, allowing for definition by
  3703   specification.  There is also an 'ax_specification' command that
  3704   introduces the new constants axiomatically.
  3705 
  3706 * arith(_tac) is now able to generate counterexamples for reals as well.
  3707 
  3708 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3709 
  3710 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3711   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3712 
  3713 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3714   matrix theory to linear programming.
  3715 
  3716 * Unions and Intersections:
  3717   The latex output syntax of UN and INT has been changed
  3718   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3719   i.e. the index formulae has become a subscript.
  3720   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3721 
  3722 * Unions and Intersections over Intervals:
  3723   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3724   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3725   like in normal math, and corresponding versions for < and for intersection.
  3726 
  3727 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3728   lexicographic dictonary ordering has been added as "lexord".
  3729 
  3730 * ML: the legacy theory structures Int and List have been removed. They had
  3731   conflicted with ML Basis Library structures having the same names.
  3732 
  3733 * 'refute' command added to search for (finite) countermodels.  Only works
  3734   for a fragment of HOL.  The installation of an external SAT solver is
  3735   highly recommended.  See "HOL/Refute.thy" for details.
  3736 
  3737 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3738   formulae under an assignment of free variables to random values.
  3739   In contrast to 'refute', it can deal with inductive datatypes,
  3740   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3741   for examples.
  3742 
  3743 
  3744 *** HOLCF ***
  3745 
  3746 * Streams now come with concatenation and are part of the HOLCF image
  3747 
  3748 
  3749 
  3750 New in Isabelle2003 (May 2003)
  3751 ------------------------------
  3752 
  3753 *** General ***
  3754 
  3755 * Provers/simplifier:
  3756 
  3757   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3758     Assumptions are now subject to complete mutual simplification,
  3759     not just from left to right. The simplifier now preserves
  3760     the order of assumptions.
  3761 
  3762     Potential INCOMPATIBILITY:
  3763 
  3764     -- simp sometimes diverges where the old version did
  3765        not, e.g. invoking simp on the goal
  3766 
  3767         [| P (f x); y = x; f x = f y |] ==> Q
  3768 
  3769        now gives rise to the infinite reduction sequence
  3770 
  3771         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3772 
  3773        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3774        kind of problem.
  3775 
  3776     -- Tactics combining classical reasoner and simplification (such as auto)
  3777        are also affected by this change, because many of them rely on
  3778        simp. They may sometimes diverge as well or yield a different numbers
  3779        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3780        in case of problems. Sometimes subsequent calls to the classical
  3781        reasoner will fail because a preceeding call to the simplifier too
  3782        eagerly simplified the goal, e.g. deleted redundant premises.
  3783 
  3784   - The simplifier trace now shows the names of the applied rewrite rules
  3785 
  3786   - You can limit the number of recursive invocations of the simplifier
  3787     during conditional rewriting (where the simplifie tries to solve the
  3788     conditions before applying the rewrite rule):
  3789     ML "simp_depth_limit := n"
  3790     where n is an integer. Thus you can force termination where previously
  3791     the simplifier would diverge.
  3792 
  3793   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3794 
  3795   - No longer aborts on failed congruence proof.  Instead, the
  3796     congruence is ignored.
  3797 
  3798 * Pure: New generic framework for extracting programs from constructive
  3799   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3800   as HOL/Extraction for some case studies.
  3801 
  3802 * Pure: The main goal of the proof state is no longer shown by default, only
  3803 the subgoals. This behaviour is controlled by a new flag.
  3804    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3805 (ML: Proof.show_main_goal).
  3806 
  3807 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3808 rules whose conclusion matches subgoal 1:
  3809       PG menu: Isabelle/Isar -> Show me -> matching rules
  3810 The rules are ordered by how closely they match the subgoal.
  3811 In particular, rules that solve a subgoal outright are displayed first
  3812 (or rather last, the way they are printed).
  3813 (ML: ProofGeneral.print_intros())
  3814 
  3815 * Pure: New flag trace_unify_fail causes unification to print
  3816 diagnostic information (PG: in trace buffer) when it fails. This is
  3817 useful for figuring out why single step proofs like rule, erule or
  3818 assumption failed.
  3819 
  3820 * Pure: Locale specifications now produce predicate definitions
  3821 according to the body of text (covering assumptions modulo local
  3822 definitions); predicate "loc_axioms" covers newly introduced text,
  3823 while "loc" is cumulative wrt. all included locale expressions; the
  3824 latter view is presented only on export into the global theory
  3825 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3826 on the old view without predicates;
  3827 
  3828 * Pure: predefined locales "var" and "struct" are useful for sharing
  3829 parameters (as in CASL, for example); just specify something like
  3830 ``var x + var y + struct M'' as import;
  3831 
  3832 * Pure: improved thms_containing: proper indexing of facts instead of
  3833 raw theorems; check validity of results wrt. current name space;
  3834 include local facts of proof configuration (also covers active
  3835 locales), cover fixed variables in index; may use "_" in term
  3836 specification; an optional limit for the number of printed facts may
  3837 be given (the default is 40);
  3838 
  3839 * Pure: disallow duplicate fact bindings within new-style theory files
  3840 (batch-mode only);
  3841 
  3842 * Provers: improved induct method: assumptions introduced by case
  3843 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3844 the goal statement); "foo" still refers to all facts collectively;
  3845 
  3846 * Provers: the function blast.overloaded has been removed: all constants
  3847 are regarded as potentially overloaded, which improves robustness in exchange
  3848 for slight decrease in efficiency;
  3849 
  3850 * Provers/linorder: New generic prover for transitivity reasoning over
  3851 linear orders.  Note: this prover is not efficient!
  3852 
  3853 * Isar: preview of problems to finish 'show' now produce an error
  3854 rather than just a warning (in interactive mode);
  3855 
  3856 
  3857 *** HOL ***
  3858 
  3859 * arith(_tac)
  3860 
  3861  - Produces a counter example if it cannot prove a goal.
  3862    Note that the counter example may be spurious if the goal is not a formula
  3863    of quantifier-free linear arithmetic.
  3864    In ProofGeneral the counter example appears in the trace buffer.
  3865 
  3866  - Knows about div k and mod k where k is a numeral of type nat or int.
  3867 
  3868  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3869    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3870    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3871 
  3872 * simp's arithmetic capabilities have been enhanced a bit: it now
  3873 takes ~= in premises into account (by performing a case split);
  3874 
  3875 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3876 are distributed over a sum of terms;
  3877 
  3878 * New tactic "trans_tac" and method "trans" instantiate
  3879 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3880 "<=", "<" and "=").
  3881 
  3882 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3883 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3884 
  3885 * 'typedef' command has new option "open" to suppress the set
  3886 definition;
  3887 
  3888 * functions Min and Max on finite sets have been introduced (theory
  3889 Finite_Set);
  3890 
  3891 * attribute [symmetric] now works for relations as well; it turns
  3892 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3893 
  3894 * induct over a !!-quantified statement (say !!x1..xn):
  3895   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3896 
  3897 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3898 %x. None. Warning: empty_def now refers to the previously hidden definition
  3899 of the empty set.
  3900 
  3901 * Algebra: formalization of classical algebra.  Intended as base for
  3902 any algebraic development in Isabelle.  Currently covers group theory
  3903 (up to Sylow's theorem) and ring theory (Universal Property of
  3904 Univariate Polynomials).  Contributions welcome;
  3905 
  3906 * GroupTheory: deleted, since its material has been moved to Algebra;
  3907 
  3908 * Complex: new directory of the complex numbers with numeric constants,
  3909 nonstandard complex numbers, and some complex analysis, standard and
  3910 nonstandard (Jacques Fleuriot);
  3911 
  3912 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3913 
  3914 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3915 Fleuriot);
  3916 
  3917 * Real/HahnBanach: updated and adapted to locales;
  3918 
  3919 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3920 Gray and Kramer);
  3921 
  3922 * UNITY: added the Meier-Sanders theory of progress sets;
  3923 
  3924 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3925 as abstract algorithms, instantiated to the JVM;
  3926 
  3927 * Bali: Java source language formalization. Type system, operational
  3928 semantics, axiomatic semantics. Supported language features:
  3929 classes, interfaces, objects,virtual methods, static methods,
  3930 static/instance fields, arrays, access modifiers, definite
  3931 assignment, exceptions.
  3932 
  3933 
  3934 *** ZF ***
  3935 
  3936 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3937 universe, etc.);
  3938 
  3939 * Main ZF: virtually all theories converted to new-style format;
  3940 
  3941 
  3942 *** ML ***
  3943 
  3944 * Pure: Tactic.prove provides sane interface for internal proofs;
  3945 omits the infamous "standard" operation, so this is more appropriate
  3946 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3947 
  3948 * Pure: improved error reporting of simprocs;
  3949 
  3950 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3951 up simprocs;
  3952 
  3953 
  3954 *** Document preparation ***
  3955 
  3956 * uses \par instead of \\ for line breaks in theory text. This may
  3957 shift some page breaks in large documents. To get the old behaviour
  3958 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3959 
  3960 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3961 other packages
  3962 
  3963 * \<euro> now needs package babel/greek instead of marvosym (which
  3964 broke \Rightarrow)
  3965 
  3966 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3967 textcomp package)
  3968 
  3969 
  3970 
  3971 New in Isabelle2002 (March 2002)
  3972 --------------------------------
  3973 
  3974 *** Document preparation ***
  3975 
  3976 * greatly simplified document preparation setup, including more
  3977 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3978 instructive isatool mkdir; users should basically be able to get
  3979 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3980 users may run a separate document processing stage manually like this:
  3981 "isatool usedir -D output HOL Test && isatool document Test/output";
  3982 
  3983 * theory dependency graph may now be incorporated into documents;
  3984 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3985 with \includegraphics of LaTeX;
  3986 
  3987 * proper spacing of consecutive markup elements, especially text
  3988 blocks after section headings;
  3989 
  3990 * support bold style (for single symbols only), input syntax is like
  3991 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3992 
  3993 * \<bullet> is now output as bold \cdot by default, which looks much
  3994 better in printed text;
  3995 
  3996 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3997 note that these symbols are currently unavailable in Proof General /
  3998 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3999 
  4000 * isatool latex no longer depends on changed TEXINPUTS, instead
  4001 isatool document copies the Isabelle style files to the target
  4002 location;
  4003 
  4004 
  4005 *** Isar ***
  4006 
  4007 * Pure/Provers: improved proof by cases and induction;
  4008   - 'case' command admits impromptu naming of parameters (such as
  4009     "case (Suc n)");
  4010   - 'induct' method divinates rule instantiation from the inductive
  4011     claim; no longer requires excessive ?P bindings for proper
  4012     instantiation of cases;
  4013   - 'induct' method properly enumerates all possibilities of set/type
  4014     rules; as a consequence facts may be also passed through *type*
  4015     rules without further ado;
  4016   - 'induct' method now derives symbolic cases from the *rulified*
  4017     rule (before it used to rulify cases stemming from the internal
  4018     atomized version); this means that the context of a non-atomic
  4019     statement becomes is included in the hypothesis, avoiding the
  4020     slightly cumbersome show "PROP ?case" form;
  4021   - 'induct' may now use elim-style induction rules without chaining
  4022     facts, using ``missing'' premises from the goal state; this allows
  4023     rules stemming from inductive sets to be applied in unstructured
  4024     scripts, while still benefitting from proper handling of non-atomic
  4025     statements; NB: major inductive premises need to be put first, all
  4026     the rest of the goal is passed through the induction;
  4027   - 'induct' proper support for mutual induction involving non-atomic
  4028     rule statements (uses the new concept of simultaneous goals, see
  4029     below);
  4030   - append all possible rule selections, but only use the first
  4031     success (no backtracking);
  4032   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4033   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4034   - added 'print_induct_rules' (covered by help item in recent Proof
  4035     General versions);
  4036   - moved induct/cases attributes to Pure, methods to Provers;
  4037   - generic method setup instantiated for FOL and HOL;
  4038 
  4039 * Pure: support multiple simultaneous goal statements, for example
  4040 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4041 meta-level mechanism, this acts as if several individual goals had
  4042 been stated separately; in particular common proof methods need to be
  4043 repeated in order to cover all claims; note that a single elimination
  4044 step is *not* sufficient to establish the two conjunctions, so this
  4045 fails:
  4046 
  4047   assume "A & B" then have A and B ..   (*".." fails*)
  4048 
  4049 better use "obtain" in situations as above; alternative refer to
  4050 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4051 
  4052 * Pure: proper integration with ``locales''; unlike the original
  4053 version by Florian Kammller, Isar locales package high-level proof
  4054 contexts rather than raw logical ones (e.g. we admit to include
  4055 attributes everywhere); operations on locales include merge and
  4056 rename; support for implicit arguments (``structures''); simultaneous
  4057 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4058 some examples;
  4059 
  4060 * Pure: the following commands have been ``localized'', supporting a
  4061 target locale specification "(in name)": 'lemma', 'theorem',
  4062 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4063 stored both within the locale and at the theory level (exported and
  4064 qualified by the locale name);
  4065 
  4066 * Pure: theory goals may now be specified in ``long'' form, with
  4067 ad-hoc contexts consisting of arbitrary locale elements. for example
  4068 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4069 definitions may be given, too); the result is a meta-level rule with
  4070 the context elements being discharged in the obvious way;
  4071 
  4072 * Pure: new proof command 'using' allows to augment currently used
  4073 facts after a goal statement ('using' is syntactically analogous to
  4074 'apply', but acts on the goal's facts only); this allows chained facts
  4075 to be separated into parts given before and after a claim, as in
  4076 ``from a and b have C using d and e <proof>'';
  4077 
  4078 * Pure: renamed "antecedent" case to "rule_context";
  4079 
  4080 * Pure: new 'judgment' command records explicit information about the
  4081 object-logic embedding (used by several tools internally); no longer
  4082 use hard-wired "Trueprop";
  4083 
  4084 * Pure: added 'corollary' command;
  4085 
  4086 * Pure: fixed 'token_translation' command;
  4087 
  4088 * Pure: removed obsolete 'exported' attribute;
  4089 
  4090 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4091 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4092 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4093 
  4094 * Pure: method 'atomize' presents local goal premises as object-level
  4095 statements (atomic meta-level propositions); setup controlled via
  4096 rewrite rules declarations of 'atomize' attribute; example
  4097 application: 'induct' method with proper rule statements in improper
  4098 proof *scripts*;
  4099 
  4100 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4101 now consider the syntactic context of assumptions, giving a better
  4102 chance to get type-inference of the arguments right (this is
  4103 especially important for locales);
  4104 
  4105 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4106 mode;
  4107 
  4108 * Pure/obtain: the formal conclusion "thesis", being marked as
  4109 ``internal'', may no longer be reference directly in the text;
  4110 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4111 situations;
  4112 
  4113 * Pure: generic 'sym' attribute which declares a rule both as pure
  4114 'elim?' and for the 'symmetric' operation;
  4115 
  4116 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4117 text; the fixed correlation with particular command syntax has been
  4118 discontinued;
  4119 
  4120 * Pure: new method 'rules' is particularly well-suited for proof
  4121 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4122 but often produces more compact proof terms with less detours;
  4123 
  4124 * Pure/Provers/classical: simplified integration with pure rule
  4125 attributes and methods; the classical "intro?/elim?/dest?"
  4126 declarations coincide with the pure ones; the "rule" method no longer
  4127 includes classically swapped intros; "intro" and "elim" methods no
  4128 longer pick rules from the context; also got rid of ML declarations
  4129 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4130 INCOMPATIBILITY;
  4131 
  4132 * Provers/classical: attribute 'swapped' produces classical inversions
  4133 of introduction rules;
  4134 
  4135 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4136 rules instead of full simplifier context; 'iff' attribute handles
  4137 conditional rules;
  4138 
  4139 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4140 
  4141 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4142 "(permissive)" option to recover old behavior;
  4143 
  4144 * HOL: 'inductive' no longer features separate (collective) attributes
  4145 for 'intros' (was found too confusing);
  4146 
  4147 * HOL: properly declared induction rules less_induct and
  4148 wf_induct_rule;
  4149 
  4150 
  4151 *** HOL ***
  4152 
  4153 * HOL: moved over to sane numeral syntax; the new policy is as
  4154 follows:
  4155 
  4156   - 0 and 1 are polymorphic constants, which are defined on any
  4157   numeric type (nat, int, real etc.);
  4158 
  4159   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4160   binary representation internally;
  4161 
  4162   - type nat has special constructor Suc, and generally prefers Suc 0
  4163   over 1::nat and Suc (Suc 0) over 2::nat;
  4164 
  4165 This change may cause significant problems of INCOMPATIBILITY; here
  4166 are some hints on converting existing sources:
  4167 
  4168   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4169   entities, so expressions involving "-" (unary or binary minus) need
  4170   to be spaced properly;
  4171 
  4172   - existing occurrences of "1" may need to be constraint "1::nat" or
  4173   even replaced by Suc 0; similar for old "2";
  4174 
  4175   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4176 
  4177   - remove all special provisions on numerals in proofs;
  4178 
  4179 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4180 representation (depends on bin_arith_simps in the default context);
  4181 
  4182 * HOL: symbolic syntax for x^2 (numeral 2);
  4183 
  4184 * HOL: the class of all HOL types is now called "type" rather than
  4185 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4186 in axclass/classes, instance/arities, and (usually rare) occurrences
  4187 in typings (of consts etc.); internally the class is called
  4188 "HOL.type", ML programs should refer to HOLogic.typeS;
  4189 
  4190 * HOL/record package improvements:
  4191   - new derived operations "fields" to build a partial record section,
  4192     "extend" to promote a fixed record to a record scheme, and
  4193     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4194     declared as simp by default;
  4195   - shared operations ("more", "fields", etc.) now need to be always
  4196     qualified) --- potential INCOMPATIBILITY;
  4197   - removed "make_scheme" operations (use "make" with "extend") --
  4198     INCOMPATIBILITY;
  4199   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4200   - provides cases/induct rules for use with corresponding Isar
  4201     methods (for concrete records, record schemes, concrete more
  4202     parts, and schematic more parts -- in that order);
  4203   - internal definitions directly based on a light-weight abstract
  4204     theory of product types over typedef rather than datatype;
  4205 
  4206 * HOL: generic code generator for generating executable ML code from
  4207 specifications; specific support for HOL constructs such as inductive
  4208 datatypes and sets, as well as recursive functions; can be invoked
  4209 via 'generate_code' theory section;
  4210 
  4211 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4212 
  4213 * HOL: consolidated and renamed several theories.  In particular:
  4214         Ord.thy has been absorbed into HOL.thy
  4215         String.thy has been absorbed into List.thy
  4216 
  4217 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4218 (beware of argument permutation!);
  4219 
  4220 * HOL: linorder_less_split superseded by linorder_cases;
  4221 
  4222 * HOL/List: "nodups" renamed to "distinct";
  4223 
  4224 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4225 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4226   - Ex_def has changed, now need to use some_eq_ex
  4227 
  4228 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4229 in this (rare) case use:
  4230 
  4231   delSWrapper "split_all_tac"
  4232   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4233 
  4234 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4235 MAY FAIL;
  4236 
  4237 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4238 Isabelle's type classes, ^ on functions and relations has too general
  4239 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4240 necessary to attach explicit type constraints;
  4241 
  4242 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4243 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4244 renamed accordingly (eg "compI" -> "rel_compI").
  4245 
  4246 * HOL: syntax translations now work properly with numerals and records
  4247 expressions;
  4248 
  4249 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4250 of "lam" -- INCOMPATIBILITY;
  4251 
  4252 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4253 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4254 renamed "Product_Type.unit";
  4255 
  4256 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4257 
  4258 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4259 the "cases" method);
  4260 
  4261 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4262 Florian Kammller);
  4263 
  4264 * HOL/IMP: updated and converted to new-style theory format; several
  4265 parts turned into readable document, with proper Isar proof texts and
  4266 some explanations (by Gerwin Klein);
  4267 
  4268 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4269 
  4270 * HOL-Hyperreal is now a logic image;
  4271 
  4272 
  4273 *** HOLCF ***
  4274 
  4275 * Isar: consts/constdefs supports mixfix syntax for continuous
  4276 operations;
  4277 
  4278 * Isar: domain package adapted to new-style theory format, e.g. see
  4279 HOLCF/ex/Dnat.thy;
  4280 
  4281 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4282 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4283 lift.induct_tac, always use UU instead of Undef;
  4284 
  4285 * HOLCF/IMP: updated and converted to new-style theory;
  4286 
  4287 
  4288 *** ZF ***
  4289 
  4290 * Isar: proper integration of logic-specific tools and packages,
  4291 including theory commands '(co)inductive', '(co)datatype',
  4292 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4293 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4294 
  4295 * theory Main no longer includes AC; for the Axiom of Choice, base
  4296 your theory on Main_ZFC;
  4297 
  4298 * the integer library now covers quotients and remainders, with many
  4299 laws relating division to addition, multiplication, etc.;
  4300 
  4301 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4302 typeless version of the formalism;
  4303 
  4304 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4305 format;
  4306 
  4307 * ZF/Induct: new directory for examples of inductive definitions,
  4308 including theory Multiset for multiset orderings; converted to
  4309 new-style theory format;
  4310 
  4311 * ZF: many new theorems about lists, ordinals, etc.;
  4312 
  4313 
  4314 *** General ***
  4315 
  4316 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4317 variable proof controls level of detail: 0 = no proofs (only oracle
  4318 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4319 also ref manual for further ML interfaces;
  4320 
  4321 * Pure/axclass: removed obsolete ML interface
  4322 goal_subclass/goal_arity;
  4323 
  4324 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4325 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4326 separate tokens, so expressions involving minus need to be spaced
  4327 properly;
  4328 
  4329 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4330 rather than "infixl" or "infixr";
  4331 
  4332 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4333 sort constraint specifications in type inference; e.g. "x::_::foo"
  4334 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4335 type variable);
  4336 
  4337 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4338 control output of nested => (types); the default behavior is
  4339 "type_brackets";
  4340 
  4341 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4342 tokens into AST constants;
  4343 
  4344 * Pure/syntax: prefer later declarations of translations and print
  4345 translation functions; potential INCOMPATIBILITY: need to reverse
  4346 multiple declarations for same syntax element constant;
  4347 
  4348 * Pure/show_hyps reset by default (in accordance to existing Isar
  4349 practice);
  4350 
  4351 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4352 addSafter;
  4353 
  4354 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4355 as well;
  4356 
  4357 * system: tested support for MacOS X; should be able to get Isabelle +
  4358 Proof General to work in a plain Terminal after installing Poly/ML
  4359 (e.g. from the Isabelle distribution area) and GNU bash alone
  4360 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4361 support requires further installations, e.g. from
  4362 http://fink.sourceforge.net/);
  4363 
  4364 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4365 
  4366 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4367 of 40 MB), cf. ML_OPTIONS;
  4368 
  4369 * system: Proof General keywords specification is now part of the
  4370 Isabelle distribution (see etc/isar-keywords.el);
  4371 
  4372 * system: support for persistent Proof General sessions (refrain from
  4373 outdating all loaded theories on startup); user may create writable
  4374 logic images like this: ``isabelle -q HOL Test'';
  4375 
  4376 * system: smart selection of Isabelle process versus Isabelle
  4377 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4378 run both "isabelle" and "Isabelle" even if file names are badly
  4379 damaged (executable inspects the case of the first letter of its own
  4380 name); added separate "isabelle-process" and "isabelle-interface";
  4381 
  4382 * system: refrain from any attempt at filtering input streams; no
  4383 longer support ``8bit'' encoding of old isabelle font, instead proper
  4384 iso-latin characters may now be used; the related isatools
  4385 "symbolinput" and "nonascii" have disappeared as well;
  4386 
  4387 * system: removed old "xterm" interface (the print modes "xterm" and
  4388 "xterm_color" are still available for direct use in a suitable
  4389 terminal);
  4390 
  4391 
  4392 
  4393 New in Isabelle99-2 (February 2001)
  4394 -----------------------------------
  4395 
  4396 *** Overview of INCOMPATIBILITIES ***
  4397 
  4398 * HOL: please note that theories in the Library and elsewhere often use the
  4399 new-style (Isar) format; to refer to their theorems in an ML script you must
  4400 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4401 
  4402 * HOL: inductive package no longer splits induction rule aggressively,
  4403 but only as far as specified by the introductions given; the old
  4404 format may be recovered via ML function complete_split_rule or attribute
  4405 'split_rule (complete)';
  4406 
  4407 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4408 gfp_Tarski to gfp_unfold;
  4409 
  4410 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4411 
  4412 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4413 relation); infix "^^" has been renamed "``"; infix "``" has been
  4414 renamed "`"; "univalent" has been renamed "single_valued";
  4415 
  4416 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4417 operation;
  4418 
  4419 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4420 
  4421 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4422 
  4423 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4424 consequence, it is no longer monotonic wrt. the local goal context
  4425 (which is now passed through the inductive cases);
  4426 
  4427 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4428 \<gg> to \<ggreater>;
  4429 
  4430 
  4431 *** Document preparation ***
  4432 
  4433 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4434 available: are "it" for near math-mode best-style output, "sl" for
  4435 slanted text style, and "tt" for plain type-writer; if no
  4436 \isabellestyle command is given, output is according to slanted
  4437 type-writer);
  4438 
  4439 * support sub/super scripts (for single symbols only), input syntax is
  4440 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4441 
  4442 * some more standard symbols; see Appendix A of the system manual for
  4443 the complete list of symbols defined in isabellesym.sty;
  4444 
  4445 * improved isabelle style files; more abstract symbol implementation
  4446 (should now use \isamath{...} and \isatext{...} in custom symbol
  4447 definitions);
  4448 
  4449 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4450 state; Note that presentation of goal states does not conform to
  4451 actual human-readable proof documents.  Please do not include goal
  4452 states into document output unless you really know what you are doing!
  4453 
  4454 * proper indentation of antiquoted output with proportional LaTeX
  4455 fonts;
  4456 
  4457 * no_document ML operator temporarily disables LaTeX document
  4458 generation;
  4459 
  4460 * isatool unsymbolize tunes sources for plain ASCII communication;
  4461 
  4462 
  4463 *** Isar ***
  4464 
  4465 * Pure: Isar now suffers initial goal statements to contain unbound
  4466 schematic variables (this does not conform to actual readable proof
  4467 documents, due to unpredictable outcome and non-compositional proof
  4468 checking); users who know what they are doing may use schematic goals
  4469 for Prolog-style synthesis of proven results;
  4470 
  4471 * Pure: assumption method (an implicit finishing) now handles actual
  4472 rules as well;
  4473 
  4474 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4475 initial goal, declare "that" only as Pure intro (only for single
  4476 steps); the "that" rule assumption may now be involved in implicit
  4477 finishing, thus ".." becomes a feasible for trivial obtains;
  4478 
  4479 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4480 instance proofs may be performed by "..";
  4481 
  4482 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4483 statements as well;
  4484 
  4485 * Pure: more robust selection of calculational rules;
  4486 
  4487 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4488 rule (as well as the assumption rule);
  4489 
  4490 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4491 lemmas, using the graph browser tool;
  4492 
  4493 * Pure: predict failure of "show" in interactive mode;
  4494 
  4495 * Pure: 'thms_containing' now takes actual terms as arguments;
  4496 
  4497 * HOL: improved method 'induct' --- now handles non-atomic goals
  4498 (potential INCOMPATIBILITY); tuned error handling;
  4499 
  4500 * HOL: cases and induct rules now provide explicit hints about the
  4501 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4502 any remaining facts are inserted into the goal verbatim;
  4503 
  4504 * HOL: local contexts (aka cases) may now contain term bindings as
  4505 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4506 the result to be shown in each case;
  4507 
  4508 * HOL: added 'recdef_tc' command;
  4509 
  4510 * isatool convert assists in eliminating legacy ML scripts;
  4511 
  4512 
  4513 *** HOL ***
  4514 
  4515 * HOL/Library: a collection of generic theories to be used together
  4516 with main HOL; the theory loader path already includes this directory
  4517 by default; the following existing theories have been moved here:
  4518 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4519 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4520 
  4521 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4522 modelling and verification task performed in Isabelle/HOL +
  4523 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4524 
  4525 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4526 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4527 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4528 'domain', this makes the theory consistent with mathematical
  4529 literature;
  4530 
  4531 * HOL basics: added overloaded operations "inverse" and "divide"
  4532 (infix "/"), syntax for generic "abs" operation, generic summation
  4533 operator \<Sum>;
  4534 
  4535 * HOL/typedef: simplified package, provide more useful rules (see also
  4536 HOL/subset.thy);
  4537 
  4538 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4539 now expressed as a proper nested rule (old-style tactic scripts may
  4540 require atomize_strip_tac to cope with non-atomic premises);
  4541 
  4542 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4543 to "split_conv" (old name still available for compatibility);
  4544 
  4545 * HOL: improved concrete syntax for strings (e.g. allows translation
  4546 rules with string literals);
  4547 
  4548 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4549  and Fleuriot's mechanization of analysis, including the transcendental
  4550  functions for the reals;
  4551 
  4552 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4553 
  4554 
  4555 *** CTT ***
  4556 
  4557 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4558 "lam" is displayed as TWO lambda-symbols
  4559 
  4560 * CTT: theory Main now available, containing everything (that is, Bool
  4561 and Arith);
  4562 
  4563 
  4564 *** General ***
  4565 
  4566 * Pure: the Simplifier has been implemented properly as a derived rule
  4567 outside of the actual kernel (at last!); the overall performance
  4568 penalty in practical applications is about 50%, while reliability of
  4569 the Isabelle inference kernel has been greatly improved;
  4570 
  4571 * print modes "brackets" and "no_brackets" control output of nested =>
  4572 (types) and ==> (props); the default behaviour is "brackets";
  4573 
  4574 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4575 as assumptions as well;
  4576 
  4577 * system: support Poly/ML 4.0;
  4578 
  4579 * system: isatool install handles KDE version 1 or 2;
  4580 
  4581 
  4582 
  4583 New in Isabelle99-1 (October 2000)
  4584 ----------------------------------
  4585 
  4586 *** Overview of INCOMPATIBILITIES ***
  4587 
  4588 * HOL: simplification of natural numbers is much changed; to partly
  4589 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4590 issue the following ML commands:
  4591 
  4592   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4593   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4594 
  4595 * HOL: simplification no longer dives into case-expressions; this is
  4596 controlled by "t.weak_case_cong" for each datatype t;
  4597 
  4598 * HOL: nat_less_induct renamed to less_induct;
  4599 
  4600 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4601 fixsome to patch .thy and .ML sources automatically;
  4602 
  4603   select_equality  -> some_equality
  4604   select_eq_Ex     -> some_eq_ex
  4605   selectI2EX       -> someI2_ex
  4606   selectI2         -> someI2
  4607   selectI          -> someI
  4608   select1_equality -> some1_equality
  4609   Eps_sym_eq       -> some_sym_eq_trivial
  4610   Eps_eq           -> some_eq_trivial
  4611 
  4612 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4613 
  4614 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4615 instead);
  4616 
  4617 * HOL: the recursion equations generated by 'recdef' are now called
  4618 f.simps instead of f.rules;
  4619 
  4620 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4621 
  4622 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4623 sometimes be needed;
  4624 
  4625 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4626 
  4627 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4628 
  4629 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4630 product is now "<*>" instead of "Times"; the lexicographic product is
  4631 now "<*lex*>" instead of "**";
  4632 
  4633 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4634 of main HOL, but was unused); better use HOL's datatype package;
  4635 
  4636 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4637 the old syntax may be recovered as follows:
  4638 
  4639   syntax (symbols)
  4640     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4641       (infixl "\\<oplus>" 100)
  4642 
  4643 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4644 
  4645 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4646 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4647 internally;
  4648 
  4649 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4650 changed from A/r to A//r;
  4651 
  4652 * ZF: new treatment of arithmetic (nat & int) may break some old
  4653 proofs;
  4654 
  4655 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4656 rulify -> rule_format, elimify -> elim_format, ...);
  4657 
  4658 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4659 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4660 should have to change intro!! to intro? only); replaced "delrule" by
  4661 "rule del";
  4662 
  4663 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4664 
  4665 * Provers: strengthened force_tac by using new first_best_tac;
  4666 
  4667 * LaTeX document preparation: several changes of isabelle.sty (see
  4668 lib/texinputs);
  4669 
  4670 
  4671 *** Document preparation ***
  4672 
  4673 * formal comments (text blocks etc.) in new-style theories may now
  4674 contain antiquotations of thm/prop/term/typ/text to be presented
  4675 according to latex print mode; concrete syntax is like this:
  4676 @{term[show_types] "f(x) = a + x"};
  4677 
  4678 * isatool mkdir provides easy setup of Isabelle session directories,
  4679 including proper document sources;
  4680 
  4681 * generated LaTeX sources are now deleted after successful run
  4682 (isatool document -c); may retain a copy somewhere else via -D option
  4683 of isatool usedir;
  4684 
  4685 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4686 style files, achieving self-contained LaTeX sources and simplifying
  4687 LaTeX debugging;
  4688 
  4689 * old-style theories now produce (crude) LaTeX output as well;
  4690 
  4691 * browser info session directories are now self-contained (may be put
  4692 on WWW server seperately); improved graphs of nested sessions; removed
  4693 graph for 'all sessions';
  4694 
  4695 * several improvements in isabelle style files; \isabellestyle{it}
  4696 produces fake math mode output; \isamarkupheader is now \section by
  4697 default; see lib/texinputs/isabelle.sty etc.;
  4698 
  4699 
  4700 *** Isar ***
  4701 
  4702 * Isar/Pure: local results and corresponding term bindings are now
  4703 subject to Hindley-Milner polymorphism (similar to ML); this
  4704 accommodates incremental type-inference very nicely;
  4705 
  4706 * Isar/Pure: new derived language element 'obtain' supports
  4707 generalized existence reasoning;
  4708 
  4709 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4710 support accumulation of results, without applying any rules yet;
  4711 useful to collect intermediate results without explicit name
  4712 references, and for use with transitivity rules with more than 2
  4713 premises;
  4714 
  4715 * Isar/Pure: scalable support for case-analysis type proofs: new
  4716 'case' language element refers to local contexts symbolically, as
  4717 produced by certain proof methods; internally, case names are attached
  4718 to theorems as "tags";
  4719 
  4720 * Isar/Pure: theory command 'hide' removes declarations from
  4721 class/type/const name spaces;
  4722 
  4723 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4724 indicate potential overloading;
  4725 
  4726 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4727 
  4728 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4729 "{a,b,c}" instead of {a,b,c};
  4730 
  4731 * Isar/Pure now provides its own version of intro/elim/dest
  4732 attributes; useful for building new logics, but beware of confusion
  4733 with the version in Provers/classical;
  4734 
  4735 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4736 case name 'antecedent';
  4737 
  4738 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4739 to the current context is now done automatically);
  4740 
  4741 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4742 for definining proof methods in ML;
  4743 
  4744 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4745 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4746 most cases, one should have to change intro!! to intro? only);
  4747 replaced "delrule" by "rule del";
  4748 
  4749 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4750 'symmetric' attribute (the latter supercedes [RS sym]);
  4751 
  4752 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4753 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4754 well (including splits);
  4755 
  4756 * Isar/Provers: Simplifier and Classical methods now support all kind
  4757 of modifiers used in the past, including 'cong', 'iff', etc.
  4758 
  4759 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4760 of Simplifier and Classical reasoner);
  4761 
  4762 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4763 now support named cases; major packages (inductive, datatype, primrec,
  4764 recdef) support case names and properly name parameters;
  4765 
  4766 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4767 monotonicity conditions are extracted to be proven at end of
  4768 calculations;
  4769 
  4770 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4771 method anyway;
  4772 
  4773 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4774 split_if split_if_asm; datatype package provides theorems foo.splits =
  4775 foo.split foo.split_asm for each datatype;
  4776 
  4777 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4778 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4779 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4780 use "(cases (simplified))" method in proper proof texts);
  4781 
  4782 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4783 
  4784 * Isar: names of theorems etc. may be natural numbers as well;
  4785 
  4786 * Isar: 'pr' command: optional arguments for goals_limit and
  4787 ProofContext.prems_limit; no longer prints theory contexts, but only
  4788 proof states;
  4789 
  4790 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4791 additional print modes to be specified; e.g. "pr(latex)" will print
  4792 proof state according to the Isabelle LaTeX style;
  4793 
  4794 * Isar: improved support for emulating tactic scripts, including proof
  4795 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4796 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4797 (for HOL datatypes);
  4798 
  4799 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4800 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4801 'proof method scripts' have to be in depth-first order;
  4802 
  4803 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4804 
  4805 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4806 should instead use individual commands for printing items
  4807 (print_commands, print_methods etc.);
  4808 
  4809 * Isar: added 'nothing' --- the empty list of theorems;
  4810 
  4811 
  4812 *** HOL ***
  4813 
  4814 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4815 corresponding virtual machine and a specification of its bytecode
  4816 verifier and a lightweight bytecode verifier, including proofs of
  4817 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4818 Cornelia Pusch (see also the homepage of project Bali at
  4819 http://isabelle.in.tum.de/Bali/);
  4820 
  4821 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4822 Clemens Ballarin;
  4823 
  4824 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4825 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4826 Rasmussen;
  4827 
  4828 * HOL/Lattice: fundamental concepts of lattice theory and order
  4829 structures, including duals, properties of bounds versus algebraic
  4830 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4831 Theorem for complete lattices etc.; may also serve as a demonstration
  4832 for abstract algebraic reasoning using axiomatic type classes, and
  4833 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4834 
  4835 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4836 von Oheimb;
  4837 
  4838 * HOL/IMPP: extension of IMP with local variables and mutually
  4839 recursive procedures, by David von Oheimb;
  4840 
  4841 * HOL/Lambda: converted into new-style theory and document;
  4842 
  4843 * HOL/ex/Multiquote: example of multiple nested quotations and
  4844 anti-quotations -- basically a generalized version of de-Bruijn
  4845 representation; very useful in avoiding lifting of operations;
  4846 
  4847 * HOL/record: added general record equality rule to simpset; fixed
  4848 select-update simplification procedure to handle extended records as
  4849 well; admit "r" as field name;
  4850 
  4851 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4852 other numeric types and also as the identity of groups, rings, etc.;
  4853 
  4854 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4855 Types nat and int belong to this axclass;
  4856 
  4857 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4858    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4859    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4860   two terms #m*u and #n*u are replaced by #(m+n)*u
  4861     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4862   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4863     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4864 
  4865 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4866 powerful prover for predicate logic but knows nothing of clasets; see
  4867 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4868 
  4869 * HOL: new version of "case_tac" subsumes both boolean case split and
  4870 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4871 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4872 
  4873 * HOL: simplification no longer dives into case-expressions: only the
  4874 selector expression is simplified, but not the remaining arms; to
  4875 enable full simplification of case-expressions for datatype t, you may
  4876 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4877 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4878 
  4879 * HOL/recdef: the recursion equations generated by 'recdef' for
  4880 function 'f' are now called f.simps instead of f.rules; if all
  4881 termination conditions are proved automatically, these simplification
  4882 rules are added to the simpset, as in primrec; rules may be named
  4883 individually as well, resulting in a separate list of theorems for
  4884 each equation;
  4885 
  4886 * HOL/While is a new theory that provides a while-combinator. It
  4887 permits the definition of tail-recursive functions without the
  4888 provision of a termination measure. The latter is necessary once the
  4889 invariant proof rule for while is applied.
  4890 
  4891 * HOL: new (overloaded) notation for the set of elements below/above
  4892 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4893 
  4894 * HOL: theorems impI, allI, ballI bound as "strip";
  4895 
  4896 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4897 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4898 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4899 
  4900 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4901 
  4902 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4903 main HOL, but was unused);
  4904 
  4905 * HOL: fewer consts declared as global (e.g. have to refer to
  4906 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4907 
  4908 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4909 in case of overlap with user translations (e.g. judgements over
  4910 tuples); (note that the underlying logical represenation is still
  4911 bogus);
  4912 
  4913 
  4914 *** ZF ***
  4915 
  4916 * ZF: simplification automatically cancels common terms in arithmetic
  4917 expressions over nat and int;
  4918 
  4919 * ZF: new treatment of nat to minimize type-checking: all operators
  4920 coerce their operands to a natural number using the function natify,
  4921 making the algebraic laws unconditional;
  4922 
  4923 * ZF: as above, for int: operators coerce their operands to an integer
  4924 using the function intify;
  4925 
  4926 * ZF: the integer library now contains many of the usual laws for the
  4927 orderings, including $<=, and monotonicity laws for $+ and $*;
  4928 
  4929 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4930 simplification;
  4931 
  4932 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4933 to the simplifier and classical reasoner simultaneously;
  4934 
  4935 
  4936 *** General ***
  4937 
  4938 * Provers: blast_tac now handles actual object-logic rules as
  4939 assumptions; note that auto_tac uses blast_tac internally as well;
  4940 
  4941 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4942 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4943 
  4944 * Provers: delrules now handles destruct rules as well (no longer need
  4945 explicit make_elim);
  4946 
  4947 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4948   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4949 use instead the strong form,
  4950   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4951 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4952 from destruct-rules;
  4953 
  4954 * Provers: Simplifier.easy_setup provides a fast path to basic
  4955 Simplifier setup for new object-logics;
  4956 
  4957 * Pure: AST translation rules no longer require constant head on LHS;
  4958 
  4959 * Pure: improved name spaces: ambiguous output is qualified; support
  4960 for hiding of names;
  4961 
  4962 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4963 XSYMBOL_HOME; no longer need to do manual configuration in most
  4964 situations;
  4965 
  4966 * system: compression of ML heaps images may now be controlled via -c
  4967 option of isabelle and isatool usedir (currently only observed by
  4968 Poly/ML);
  4969 
  4970 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4971 useful for remote X11);
  4972 
  4973 * system: provide TAGS file for Isabelle sources;
  4974 
  4975 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4976 order;
  4977 
  4978 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4979 timing flag supersedes proof_timing and Toplevel.trace;
  4980 
  4981 * ML: new combinators |>> and |>>> for incremental transformations
  4982 with secondary results (e.g. certain theory extensions):
  4983 
  4984 * ML: PureThy.add_defs gets additional argument to indicate potential
  4985 overloading (usually false);
  4986 
  4987 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4988 results;
  4989 
  4990 
  4991 
  4992 New in Isabelle99 (October 1999)
  4993 --------------------------------
  4994 
  4995 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4996 
  4997 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4998 are no longer simplified.  (This allows the simplifier to unfold recursive
  4999 functional programs.)  To restore the old behaviour, declare
  5000 
  5001     Delcongs [if_weak_cong];
  5002 
  5003 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5004 complement;
  5005 
  5006 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5007 
  5008 * HOL/datatype: mutual_induct_tac no longer exists --
  5009   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5010 
  5011 * HOL/typedef: fixed type inference for representing set; type
  5012 arguments now have to occur explicitly on the rhs as type constraints;
  5013 
  5014 * ZF: The con_defs part of an inductive definition may no longer refer
  5015 to constants declared in the same theory;
  5016 
  5017 * HOL, ZF: the function mk_cases, generated by the inductive
  5018 definition package, has lost an argument.  To simplify its result, it
  5019 uses the default simpset instead of a supplied list of theorems.
  5020 
  5021 * HOL/List: the constructors of type list are now Nil and Cons;
  5022 
  5023 * Simplifier: the type of the infix ML functions
  5024         setSSolver addSSolver setSolver addSolver
  5025 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5026 for packaging solvers. A solver is created via
  5027         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5028 where the string argument is only a comment.
  5029 
  5030 
  5031 *** Proof tools ***
  5032 
  5033 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5034 decision procedure for linear arithmetic. Currently it is used for
  5035 types `nat', `int', and `real' in HOL (see below); it can, should and
  5036 will be instantiated for other types and logics as well.
  5037 
  5038 * The simplifier now accepts rewrite rules with flexible heads, eg
  5039      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5040   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5041   matching.
  5042 
  5043 
  5044 *** General ***
  5045 
  5046 * New Isabelle/Isar subsystem provides an alternative to traditional
  5047 tactical theorem proving; together with the ProofGeneral/isar user
  5048 interface it offers an interactive environment for developing human
  5049 readable proof documents (Isar == Intelligible semi-automated
  5050 reasoning); for further information see isatool doc isar-ref,
  5051 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5052 
  5053 * improved and simplified presentation of theories: better HTML markup
  5054 (including colors), graph views in several sizes; isatool usedir now
  5055 provides a proper interface for user theories (via -P option); actual
  5056 document preparation based on (PDF)LaTeX is available as well (for
  5057 new-style theories only); see isatool doc system for more information;
  5058 
  5059 * native support for Proof General, both for classic Isabelle and
  5060 Isabelle/Isar;
  5061 
  5062 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5063 using the graph browser tool;
  5064 
  5065 * Isabelle manuals now also available as PDF;
  5066 
  5067 * theory loader rewritten from scratch (may not be fully
  5068 bug-compatible); old loadpath variable has been replaced by show_path,
  5069 add_path, del_path, reset_path functions; new operations such as
  5070 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5071 isatool doc ref);
  5072 
  5073 * improved isatool install: option -k creates KDE application icon,
  5074 option -p DIR installs standalone binaries;
  5075 
  5076 * added ML_PLATFORM setting (useful for cross-platform installations);
  5077 more robust handling of platform specific ML images for SML/NJ;
  5078 
  5079 * the settings environment is now statically scoped, i.e. it is never
  5080 created again in sub-processes invoked from isabelle, isatool, or
  5081 Isabelle;
  5082 
  5083 * path element specification '~~' refers to '$ISABELLE_HOME';
  5084 
  5085 * in locales, the "assumes" and "defines" parts may be omitted if
  5086 empty;
  5087 
  5088 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5089 long arrows);
  5090 
  5091 * new print_mode "HTML";
  5092 
  5093 * new flag show_tags controls display of tags of theorems (which are
  5094 basically just comments that may be attached by some tools);
  5095 
  5096 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5097 mode and goal output format:
  5098 
  5099 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5100 244c244
  5101 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5102 ---
  5103 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5104 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5105 181c181
  5106 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5107 ---
  5108 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5109 
  5110 * function bind_thms stores lists of theorems (cf. bind_thm);
  5111 
  5112 * new shorthand tactics ftac, eatac, datac, fatac;
  5113 
  5114 * qed (and friends) now accept "" as result name; in that case the
  5115 theorem is not stored, but proper checks and presentation of the
  5116 result still apply;
  5117 
  5118 * theorem database now also indexes constants "Trueprop", "all",
  5119 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5120 
  5121 
  5122 *** HOL ***
  5123 
  5124 ** HOL arithmetic **
  5125 
  5126 * There are now decision procedures for linear arithmetic over nat and
  5127 int:
  5128 
  5129 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5130 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5131 are treated as atomic; subformulae not involving type `nat' or `int'
  5132 are ignored; quantified subformulae are ignored unless they are
  5133 positive universal or negative existential. The tactic has to be
  5134 invoked by hand and can be a little bit slow. In particular, the
  5135 running time is exponential in the number of occurrences of `min' and
  5136 `max', and `-' on `nat'.
  5137 
  5138 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5139 (negated) (in)equalities among the premises and the conclusion into
  5140 account (i.e. no compound formulae) and does not know about `min' and
  5141 `max', and `-' on `nat'. It is fast and is used automatically by the
  5142 simplifier.
  5143 
  5144 NB: At the moment, these decision procedures do not cope with mixed
  5145 nat/int formulae where the two parts interact, such as `m < n ==>
  5146 int(m) < int(n)'.
  5147 
  5148 * HOL/Numeral provides a generic theory of numerals (encoded
  5149 efficiently as bit strings); setup for types nat/int/real is in place;
  5150 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5151 int, existing theories and proof scripts may require a few additional
  5152 type constraints;
  5153 
  5154 * integer division and remainder can now be performed on constant
  5155 arguments;
  5156 
  5157 * many properties of integer multiplication, division and remainder
  5158 are now available;
  5159 
  5160 * An interface to the Stanford Validity Checker (SVC) is available through the
  5161 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5162 are proved automatically.  SVC must be installed separately, and its results
  5163 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5164 invocation of the underlying oracle).  For SVC see
  5165   http://verify.stanford.edu/SVC
  5166 
  5167 * IsaMakefile: the HOL-Real target now builds an actual image;
  5168 
  5169 
  5170 ** HOL misc **
  5171 
  5172 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5173 (in Isabelle/Isar) -- by Gertrud Bauer;
  5174 
  5175 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5176 analysis for assembly languages with subtypes;
  5177 
  5178 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5179 -- avoids syntactic ambiguities and treats state, transition, and
  5180 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5181 changed syntax and (many) tactics;
  5182 
  5183 * HOL/inductive: Now also handles more general introduction rules such
  5184   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5185   theorems are now maintained within the theory (maintained via the
  5186   "mono" attribute);
  5187 
  5188 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5189   (using function types) such as
  5190 
  5191   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5192 
  5193 * HOL/record: record_simproc (part of the default simpset) takes care
  5194 of selectors applied to updated records; record_split_tac is no longer
  5195 part of the default claset; update_defs may now be removed from the
  5196 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5197 
  5198   claset_ref () := claset() addSWrapper record_split_wrapper;
  5199   Delsimprocs [record_simproc]
  5200 
  5201 * HOL/typedef: fixed type inference for representing set; type
  5202 arguments now have to occur explicitly on the rhs as type constraints;
  5203 
  5204 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5205 names rather than an ML expression;
  5206 
  5207 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5208 supplied later.  Program schemes can be defined, such as
  5209     "While B C s = (if B s then While B C (C s) else s)"
  5210 where the well-founded relation can be chosen after B and C have been given.
  5211 
  5212 * HOL/List: the constructors of type list are now Nil and Cons;
  5213 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5214 course, ML tools referring to List.list.op # etc. have to be adapted;
  5215 
  5216 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5217 disabled by default; run isabelle with option -m HOL to get back to
  5218 the original Gordon/HOL-style output;
  5219 
  5220 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5221 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5222 
  5223 * HOL basic syntax simplified (more orthogonal): all variants of
  5224 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5225 Eps operator is provided as well: "SOME x. P[x]";
  5226 
  5227 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5228 
  5229 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5230 thus available for user theories;
  5231 
  5232 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5233 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5234 time;
  5235 
  5236 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5237 several times and then mp;
  5238 
  5239 
  5240 *** LK ***
  5241 
  5242 * the notation <<...>> is now available as a notation for sequences of
  5243 formulas;
  5244 
  5245 * the simplifier is now installed
  5246 
  5247 * the axiom system has been generalized (thanks to Soren Heilmann)
  5248 
  5249 * the classical reasoner now has a default rule database
  5250 
  5251 
  5252 *** ZF ***
  5253 
  5254 * new primrec section allows primitive recursive functions to be given
  5255 directly (as in HOL) over datatypes and the natural numbers;
  5256 
  5257 * new tactics induct_tac and exhaust_tac for induction (or case
  5258 analysis) over datatypes and the natural numbers;
  5259 
  5260 * the datatype declaration of type T now defines the recursor T_rec;
  5261 
  5262 * simplification automatically does freeness reasoning for datatype
  5263 constructors;
  5264 
  5265 * automatic type-inference, with AddTCs command to insert new
  5266 type-checking rules;
  5267 
  5268 * datatype introduction rules are now added as Safe Introduction rules
  5269 to the claset;
  5270 
  5271 * the syntax "if P then x else y" is now available in addition to
  5272 if(P,x,y);
  5273 
  5274 
  5275 *** Internal programming interfaces ***
  5276 
  5277 * tuned simplifier trace output; new flag debug_simp;
  5278 
  5279 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5280 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5281 
  5282 * AxClass.axclass_tac lost the theory argument;
  5283 
  5284 * tuned current_goals_markers semantics: begin / end goal avoids
  5285 printing empty lines;
  5286 
  5287 * removed prs and prs_fn hook, which was broken because it did not
  5288 include \n in its semantics, forcing writeln to add one
  5289 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5290 string -> unit if you really want to output text without newline;
  5291 
  5292 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5293 plain output, interface builders may have to enable 'isabelle_font'
  5294 mode to get Isabelle font glyphs as before;
  5295 
  5296 * refined token_translation interface; INCOMPATIBILITY: output length
  5297 now of type real instead of int;
  5298 
  5299 * theory loader actions may be traced via new ThyInfo.add_hook
  5300 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5301 your own database of information attached to *whole* theories -- as
  5302 opposed to intra-theory data slots offered via TheoryDataFun;
  5303 
  5304 * proper handling of dangling sort hypotheses (at last!);
  5305 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5306 extra sort hypotheses that can be witnessed from the type signature;
  5307 the force_strip_shyps flag is gone, any remaining shyps are simply
  5308 left in the theorem (with a warning issued by strip_shyps_warning);
  5309 
  5310 
  5311 
  5312 New in Isabelle98-1 (October 1998)
  5313 ----------------------------------
  5314 
  5315 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5316 
  5317 * several changes of automated proof tools;
  5318 
  5319 * HOL: major changes to the inductive and datatype packages, including
  5320 some minor incompatibilities of theory syntax;
  5321 
  5322 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5323 called `inj_on';
  5324 
  5325 * HOL: removed duplicate thms in Arith:
  5326   less_imp_add_less  should be replaced by  trans_less_add1
  5327   le_imp_add_le      should be replaced by  trans_le_add1
  5328 
  5329 * HOL: unary minus is now overloaded (new type constraints may be
  5330 required);
  5331 
  5332 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5333 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5334 now taken as an integer constant.
  5335 
  5336 * Pure: ML function 'theory_of' renamed to 'theory';
  5337 
  5338 
  5339 *** Proof tools ***
  5340 
  5341 * Simplifier:
  5342   1. Asm_full_simp_tac is now more aggressive.
  5343      1. It will sometimes reorient premises if that increases their power to
  5344         simplify.
  5345      2. It does no longer proceed strictly from left to right but may also
  5346         rotate premises to achieve further simplification.
  5347      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5348      old Asm_full_simp_tac in that it does not rotate premises.
  5349   2. The simplifier now knows a little bit about nat-arithmetic.
  5350 
  5351 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5352 allows for selected deletion of wrappers, by introduction of names for
  5353 wrapper functionals.  This implies that addbefore, addSbefore,
  5354 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5355 and that adding two tactics with the same name overwrites the first
  5356 one (emitting a warning).
  5357   type wrapper = (int -> tactic) -> (int -> tactic)
  5358   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5359   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5360   delWrapper, delSWrapper: claset *  string            -> claset
  5361   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5362 
  5363 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5364 semantics; addbefore now affects only the unsafe part of step_tac
  5365 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5366 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5367 by Force_tac;
  5368 
  5369 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5370 compWrapper; added safe wrapper (and access functions for it);
  5371 
  5372 * HOL/split_all_tac is now much faster and fails if there is nothing
  5373 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5374 and the names of the automatically generated variables have changed.
  5375 split_all_tac has moved within claset() from unsafe wrappers to safe
  5376 wrappers, which means that !!-bound variables are split much more
  5377 aggressively, and safe_tac and clarify_tac now split such variables.
  5378 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5379 Note: the same holds for record_split_tac, which does the job of
  5380 split_all_tac for record fields.
  5381 
  5382 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5383 permanently to the default simpset using Addsplits just like
  5384 Addsimps. They can be removed via Delsplits just like
  5385 Delsimps. Lower-case versions are also available.
  5386 
  5387 * HOL/Simplifier: The rule split_if is now part of the default
  5388 simpset. This means that the simplifier will eliminate all occurrences
  5389 of if-then-else in the conclusion of a goal. To prevent this, you can
  5390 either remove split_if completely from the default simpset by
  5391 `Delsplits [split_if]' or remove it in a specific call of the
  5392 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5393 other case splitting rules to/from the default simpset: every datatype
  5394 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5395 t is the name of the datatype).
  5396 
  5397 * Classical reasoner / Simplifier combination: new force_tac (and
  5398 derivatives Force_tac, force) combines rewriting and classical
  5399 reasoning (and whatever other tools) similarly to auto_tac, but is
  5400 aimed to solve the given subgoal completely.
  5401 
  5402 
  5403 *** General ***
  5404 
  5405 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5406 and `goalw': the theory is no longer needed as an explicit argument -
  5407 the current theory context is used; assumptions are no longer returned
  5408 at the ML-level unless one of them starts with ==> or !!; it is
  5409 recommended to convert to these new commands using isatool fixgoal
  5410 (backup your sources first!);
  5411 
  5412 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5413 the current theory context, and 'theory' to lookup stored theories;
  5414 
  5415 * new theory section 'locale' for declaring constants, assumptions and
  5416 definitions that have local scope;
  5417 
  5418 * new theory section 'nonterminals' for purely syntactic types;
  5419 
  5420 * new theory section 'setup' for generic ML setup functions
  5421 (e.g. package initialization);
  5422 
  5423 * the distribution now includes Isabelle icons: see
  5424 lib/logo/isabelle-{small,tiny}.xpm;
  5425 
  5426 * isatool install - install binaries with absolute references to
  5427 ISABELLE_HOME/bin;
  5428 
  5429 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5430 
  5431 * print mode 'emacs' reserved for Isamode;
  5432 
  5433 * support multiple print (ast) translations per constant name;
  5434 
  5435 * theorems involving oracles are now printed with a suffixed [!];
  5436 
  5437 
  5438 *** HOL ***
  5439 
  5440 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5441 
  5442 * HOL/inductive package reorganized and improved: now supports mutual
  5443 definitions such as
  5444 
  5445   inductive EVEN ODD
  5446     intrs
  5447       null "0 : EVEN"
  5448       oddI "n : EVEN ==> Suc n : ODD"
  5449       evenI "n : ODD ==> Suc n : EVEN"
  5450 
  5451 new theorem list "elims" contains an elimination rule for each of the
  5452 recursive sets; inductive definitions now handle disjunctive premises
  5453 correctly (also ZF);
  5454 
  5455 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5456 "mutual_induct" no longer exists - the induction rule is always
  5457 contained in "induct";
  5458 
  5459 
  5460 * HOL/datatype package re-implemented and greatly improved: now
  5461 supports mutually recursive datatypes such as
  5462 
  5463   datatype
  5464     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5465             | SUM ('a aexp) ('a aexp)
  5466             | DIFF ('a aexp) ('a aexp)
  5467             | NUM 'a
  5468   and
  5469     'a bexp = LESS ('a aexp) ('a aexp)
  5470             | AND ('a bexp) ('a bexp)
  5471             | OR ('a bexp) ('a bexp)
  5472 
  5473 as well as indirectly recursive datatypes such as
  5474 
  5475   datatype
  5476     ('a, 'b) term = Var 'a
  5477                   | App 'b ((('a, 'b) term) list)
  5478 
  5479 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5480 induction on mutually / indirectly recursive datatypes.
  5481 
  5482 Primrec equations are now stored in theory and can be accessed via
  5483 <function_name>.simps.
  5484 
  5485 INCOMPATIBILITIES:
  5486 
  5487   - Theories using datatypes must now have theory Datatype as an
  5488     ancestor.
  5489   - The specific <typename>.induct_tac no longer exists - use the
  5490     generic induct_tac instead.
  5491   - natE has been renamed to nat.exhaust - use exhaust_tac
  5492     instead of res_inst_tac ... natE. Note that the variable
  5493     names in nat.exhaust differ from the names in natE, this
  5494     may cause some "fragile" proofs to fail.
  5495   - The theorems split_<typename>_case and split_<typename>_case_asm
  5496     have been renamed to <typename>.split and <typename>.split_asm.
  5497   - Since default sorts of type variables are now handled correctly,
  5498     some datatype definitions may have to be annotated with explicit
  5499     sort constraints.
  5500   - Primrec definitions no longer require function name and type
  5501     of recursive argument.
  5502 
  5503 Consider using isatool fixdatatype to adapt your theories and proof
  5504 scripts to the new package (backup your sources first!).
  5505 
  5506 
  5507 * HOL/record package: considerably improved implementation; now
  5508 includes concrete syntax for record types, terms, updates; theorems
  5509 for surjective pairing and splitting !!-bound record variables; proof
  5510 support is as follows:
  5511 
  5512   1) standard conversions (selectors or updates applied to record
  5513 constructor terms) are part of the standard simpset;
  5514 
  5515   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5516 made part of standard simpset and claset via addIffs;
  5517 
  5518   3) a tactic for record field splitting (record_split_tac) is part of
  5519 the standard claset (addSWrapper);
  5520 
  5521 To get a better idea about these rules you may retrieve them via
  5522 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5523 the name of your record type.
  5524 
  5525 The split tactic 3) conceptually simplifies by the following rule:
  5526 
  5527   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5528 
  5529 Thus any record variable that is bound by meta-all will automatically
  5530 blow up into some record constructor term, consequently the
  5531 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5532 solve record problems automatically.
  5533 
  5534 
  5535 * reorganized the main HOL image: HOL/Integ and String loaded by
  5536 default; theory Main includes everything;
  5537 
  5538 * automatic simplification of integer sums and comparisons, using cancellation;
  5539 
  5540 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5541 
  5542 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5543 
  5544 * many new identities for unions, intersections, set difference, etc.;
  5545 
  5546 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5547 called split_if, split_split, split_sum_case and split_nat_case (to go
  5548 with add/delsplits);
  5549 
  5550 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5551 (?x::unit) = (); this is made part of the default simpset, which COULD
  5552 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5553 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5554 unit_abs_eta_conv is added in order to counter the effect of
  5555 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5556 %u.f();
  5557 
  5558 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5559 makes more sense);
  5560 
  5561 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5562   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5563   disjointness reasoning but breaking a few old proofs.
  5564 
  5565 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5566 to 'converse' from 'inverse' (for compatibility with ZF and some
  5567 literature);
  5568 
  5569 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5570 the well-founded relation;
  5571 
  5572 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5573     Compl A.  The "Compl" syntax remains available as input syntax for this
  5574     release ONLY.
  5575 
  5576 * HOL/Update: new theory of function updates:
  5577     f(a:=b) == %x. if x=a then b else f x
  5578 may also be iterated as in f(a:=b,c:=d,...);
  5579 
  5580 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5581 
  5582 * HOL/List:
  5583   - new function list_update written xs[i:=v] that updates the i-th
  5584     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5585   - new function `upt' written [i..j(] which generates the list
  5586     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5587     bound write [i..j], which is a shorthand for [i..j+1(].
  5588   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5589 
  5590 * HOL/Arith:
  5591   - removed 'pred' (predecessor) function;
  5592   - generalized some theorems about n-1;
  5593   - many new laws about "div" and "mod";
  5594   - new laws about greatest common divisors (see theory ex/Primes);
  5595 
  5596 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5597 instead of "inverse";
  5598 
  5599 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5600   of the multiset ordering;
  5601 
  5602 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5603   (not included by default);
  5604 
  5605 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5606 
  5607 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5608   programs, i.e. different program variables may have different types.
  5609 
  5610 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5611   [previously, this check worked only if the rewrite rule was unconditional]
  5612   Now rew can involve either definitions or equalities (either == or =).
  5613 
  5614 
  5615 *** ZF ***
  5616 
  5617 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5618   only the theorems proved on ZF.ML;
  5619 
  5620 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5621   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5622   disjointness reasoning but breaking a few old proofs.
  5623 
  5624 * ZF/Update: new theory of function updates
  5625     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5626   may also be iterated as in f(a:=b,c:=d,...);
  5627 
  5628 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5629 
  5630 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5631   [previously, this check worked only if the rewrite rule was unconditional]
  5632   Now rew can involve either definitions or equalities (either == or =).
  5633 
  5634 * case_tac provided for compatibility with HOL
  5635     (like the old excluded_middle_tac, but with subgoals swapped)
  5636 
  5637 
  5638 *** Internal programming interfaces ***
  5639 
  5640 * Pure: several new basic modules made available for general use, see
  5641 also src/Pure/README;
  5642 
  5643 * improved the theory data mechanism to support encapsulation (data
  5644 kind name replaced by private Object.kind, acting as authorization
  5645 key); new type-safe user interface via functor TheoryDataFun; generic
  5646 print_data function becomes basically useless;
  5647 
  5648 * removed global_names compatibility flag -- all theory declarations
  5649 are qualified by default;
  5650 
  5651 * module Pure/Syntax now offers quote / antiquote translation
  5652 functions (useful for Hoare logic etc. with implicit dependencies);
  5653 see HOL/ex/Antiquote for an example use;
  5654 
  5655 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5656 cterm -> thm;
  5657 
  5658 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5659 subgoal;
  5660 
  5661 * Display.print_goals function moved to Locale.print_goals;
  5662 
  5663 * standard print function for goals supports current_goals_markers
  5664 variable for marking begin of proof, end of proof, start of goal; the
  5665 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5666 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5667 for example;
  5668 
  5669 
  5670 
  5671 New in Isabelle98 (January 1998)
  5672 --------------------------------
  5673 
  5674 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5675 
  5676 * changed lexical syntax of terms / types: dots made part of long
  5677 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5678 
  5679 * simpset (and claset) reference variable replaced by functions
  5680 simpset / simpset_ref;
  5681 
  5682 * no longer supports theory aliases (via merge) and non-trivial
  5683 implicit merge of thms' signatures;
  5684 
  5685 * most internal names of constants changed due to qualified names;
  5686 
  5687 * changed Pure/Sequence interface (see Pure/seq.ML);
  5688 
  5689 
  5690 *** General Changes ***
  5691 
  5692 * hierachically structured name spaces (for consts, types, axms, thms
  5693 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5694 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5695 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5696 long_names for fully qualified output names; NOTE: ML programs
  5697 (special tactics, packages etc.) referring to internal names may have
  5698 to be adapted to cope with fully qualified names; in case of severe
  5699 backward campatibility problems try setting 'global_names' at compile
  5700 time to have enrything declared within a flat name space; one may also
  5701 fine tune name declarations in theories via the 'global' and 'local'
  5702 section;
  5703 
  5704 * reimplemented the implicit simpset and claset using the new anytype
  5705 data filed in signatures; references simpset:simpset ref etc. are
  5706 replaced by functions simpset:unit->simpset and
  5707 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5708 to patch your ML files accordingly;
  5709 
  5710 * HTML output now includes theory graph data for display with Java
  5711 applet or isatool browser; data generated automatically via isatool
  5712 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5713 
  5714 * defs may now be conditional; improved rewrite_goals_tac to handle
  5715 conditional equations;
  5716 
  5717 * defs now admits additional type arguments, using TYPE('a) syntax;
  5718 
  5719 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5720 creates a new theory node; implicit merge of thms' signatures is
  5721 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5722 transfer:theory->thm->thm in (rare) cases;
  5723 
  5724 * improved handling of draft signatures / theories; draft thms (and
  5725 ctyps, cterms) are automatically promoted to real ones;
  5726 
  5727 * slightly changed interfaces for oracles: admit many per theory, named
  5728 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5729 
  5730 * print_goals: optional output of const types (set show_consts and
  5731 show_types);
  5732 
  5733 * improved output of warnings (###) and errors (***);
  5734 
  5735 * subgoal_tac displays a warning if the new subgoal has type variables;
  5736 
  5737 * removed old README and Makefiles;
  5738 
  5739 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5740 
  5741 * removed obsolete init_pps and init_database;
  5742 
  5743 * deleted the obsolete tactical STATE, which was declared by
  5744     fun STATE tacfun st = tacfun st st;
  5745 
  5746 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5747 (which abbreviates $HOME);
  5748 
  5749 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5750 use isatool fixseq to adapt your ML programs (this works for fully
  5751 qualified references to the Sequence structure only!);
  5752 
  5753 * use_thy no longer requires writable current directory; it always
  5754 reloads .ML *and* .thy file, if either one is out of date;
  5755 
  5756 
  5757 *** Classical Reasoner ***
  5758 
  5759 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5760 tactics that use classical reasoning to simplify a subgoal without
  5761 splitting it into several subgoals;
  5762 
  5763 * Safe_tac: like safe_tac but uses the default claset;
  5764 
  5765 
  5766 *** Simplifier ***
  5767 
  5768 * added simplification meta rules:
  5769     (asm_)(full_)simplify: simpset -> thm -> thm;
  5770 
  5771 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5772 logics (again);
  5773 
  5774 * added prems argument to simplification procedures;
  5775 
  5776 * HOL, FOL, ZF: added infix function `addsplits':
  5777   instead of `<simpset> setloop (split_tac <thms>)'
  5778   you can simply write `<simpset> addsplits <thms>'
  5779 
  5780 
  5781 *** Syntax ***
  5782 
  5783 * TYPE('a) syntax for type reflection terms;
  5784 
  5785 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5786 
  5787 * pretty printer: changed order of mixfix annotation preference (again!);
  5788 
  5789 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5790 
  5791 
  5792 *** HOL ***
  5793 
  5794 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5795   with `addloop' of the simplifier to faciliate case splitting in premises.
  5796 
  5797 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5798 
  5799 * HOL/Auth: new protocol proofs including some for the Internet
  5800   protocol TLS;
  5801 
  5802 * HOL/Map: new theory of `maps' a la VDM;
  5803 
  5804 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5805 cancelling out common nat summands from =, <, <= (in)equalities, or
  5806 differences; simplification procedures nat_cancel_factor for
  5807 cancelling common factor from =, <, <= (in)equalities over natural
  5808 sums; nat_cancel contains both kinds of procedures, it is installed by
  5809 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5810 
  5811 * HOL/simplifier: terms of the form
  5812   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5813   are rewritten to
  5814   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5815   and those of the form
  5816   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5817   are rewritten to
  5818   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5819 
  5820 * HOL/datatype
  5821   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5822 
  5823   P(t_case f1 ... fn x) =
  5824      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5825         ...
  5826        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5827      )
  5828 
  5829   and a theorem `split_t_case_asm' of the form
  5830 
  5831   P(t_case f1 ... fn x) =
  5832     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5833         ...
  5834        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5835      )
  5836   which can be added to a simpset via `addsplits'. The existing theorems
  5837   expand_list_case and expand_option_case have been renamed to
  5838   split_list_case and split_option_case.
  5839 
  5840 * HOL/Arithmetic:
  5841   - `pred n' is automatically converted to `n-1'.
  5842     Users are strongly encouraged not to use `pred' any longer,
  5843     because it will disappear altogether at some point.
  5844   - Users are strongly encouraged to write "0 < n" rather than
  5845     "n ~= 0". Theorems and proof tools have been modified towards this
  5846     `standard'.
  5847 
  5848 * HOL/Lists:
  5849   the function "set_of_list" has been renamed "set" (and its theorems too);
  5850   the function "nth" now takes its arguments in the reverse order and
  5851   has acquired the infix notation "!" as in "xs!n".
  5852 
  5853 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5854 
  5855 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5856   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5857 
  5858 * HOL/record: extensible records with schematic structural subtyping
  5859 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5860 still lacks various theorems and concrete record syntax;
  5861 
  5862 
  5863 *** HOLCF ***
  5864 
  5865 * removed "axioms" and "generated by" sections;
  5866 
  5867 * replaced "ops" section by extended "consts" section, which is capable of
  5868   handling the continuous function space "->" directly;
  5869 
  5870 * domain package:
  5871   . proves theorems immediately and stores them in the theory,
  5872   . creates hierachical name space,
  5873   . now uses normal mixfix annotations (instead of cinfix...),
  5874   . minor changes to some names and values (for consistency),
  5875   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5876   . separator between mutual domain defs: changed "," to "and",
  5877   . improved handling of sort constraints;  now they have to
  5878     appear on the left-hand side of the equations only;
  5879 
  5880 * fixed LAM <x,y,zs>.b syntax;
  5881 
  5882 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5883 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5884 
  5885 
  5886 *** FOL and ZF ***
  5887 
  5888 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5889   with `addloop' of the simplifier to faciliate case splitting in premises.
  5890 
  5891 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5892 in HOL, they strip ALL and --> from proved theorems;
  5893 
  5894 
  5895 
  5896 New in Isabelle94-8 (May 1997)
  5897 ------------------------------
  5898 
  5899 *** General Changes ***
  5900 
  5901 * new utilities to build / run / maintain Isabelle etc. (in parts
  5902 still somewhat experimental); old Makefiles etc. still functional;
  5903 
  5904 * new 'Isabelle System Manual';
  5905 
  5906 * INSTALL text, together with ./configure and ./build scripts;
  5907 
  5908 * reimplemented type inference for greater efficiency, better error
  5909 messages and clean internal interface;
  5910 
  5911 * prlim command for dealing with lots of subgoals (an easier way of
  5912 setting goals_limit);
  5913 
  5914 
  5915 *** Syntax ***
  5916 
  5917 * supports alternative (named) syntax tables (parser and pretty
  5918 printer); internal interface is provided by add_modesyntax(_i);
  5919 
  5920 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5921 be used in conjunction with the Isabelle symbol font; uses the
  5922 "symbols" syntax table;
  5923 
  5924 * added token_translation interface (may translate name tokens in
  5925 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5926 the current print_mode); IMPORTANT: user print translation functions
  5927 are responsible for marking newly introduced bounds
  5928 (Syntax.mark_boundT);
  5929 
  5930 * token translations for modes "xterm" and "xterm_color" that display
  5931 names in bold, underline etc. or colors (which requires a color
  5932 version of xterm);
  5933 
  5934 * infixes may now be declared with names independent of their syntax;
  5935 
  5936 * added typed_print_translation (like print_translation, but may
  5937 access type of constant);
  5938 
  5939 
  5940 *** Classical Reasoner ***
  5941 
  5942 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5943 some limitations.  Blast_tac...
  5944   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5945   + ignores elimination rules that don't have the correct format
  5946         (the conclusion MUST be a formula variable)
  5947   + ignores types, which can make HOL proofs fail
  5948   + rules must not require higher-order unification, e.g. apply_type in ZF
  5949     [message "Function Var's argument not a bound variable" relates to this]
  5950   + its proof strategy is more general but can actually be slower
  5951 
  5952 * substitution with equality assumptions no longer permutes other
  5953 assumptions;
  5954 
  5955 * minor changes in semantics of addafter (now called addaltern); renamed
  5956 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5957 (and access functions for it);
  5958 
  5959 * improved combination of classical reasoner and simplifier:
  5960   + functions for handling clasimpsets
  5961   + improvement of addss: now the simplifier is called _after_ the
  5962     safe steps.
  5963   + safe variant of addss called addSss: uses safe simplifications
  5964     _during_ the safe steps. It is more complete as it allows multiple
  5965     instantiations of unknowns (e.g. with slow_tac).
  5966 
  5967 *** Simplifier ***
  5968 
  5969 * added interface for simplification procedures (functions that
  5970 produce *proven* rewrite rules on the fly, depending on current
  5971 redex);
  5972 
  5973 * ordering on terms as parameter (used for ordered rewriting);
  5974 
  5975 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5976 
  5977 * the solver is now split into a safe and an unsafe part.
  5978 This should be invisible for the normal user, except that the
  5979 functions setsolver and addsolver have been renamed to setSolver and
  5980 addSolver; added safe_asm_full_simp_tac;
  5981 
  5982 
  5983 *** HOL ***
  5984 
  5985 * a generic induction tactic `induct_tac' which works for all datatypes and
  5986 also for type `nat';
  5987 
  5988 * a generic case distinction tactic `exhaust_tac' which works for all
  5989 datatypes and also for type `nat';
  5990 
  5991 * each datatype comes with a function `size';
  5992 
  5993 * patterns in case expressions allow tuple patterns as arguments to
  5994 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5995 
  5996 * primrec now also works with type nat;
  5997 
  5998 * recdef: a new declaration form, allows general recursive functions to be
  5999 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6000 
  6001 * the constant for negation has been renamed from "not" to "Not" to
  6002 harmonize with FOL, ZF, LK, etc.;
  6003 
  6004 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6005 infinite lists;
  6006 
  6007 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6008 
  6009 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6010 problems in commutative rings, using axiomatic type classes for + and *;
  6011 
  6012 * more examples in HOL/MiniML and HOL/Auth;
  6013 
  6014 * more default rewrite rules for quantifiers, union/intersection;
  6015 
  6016 * a new constant `arbitrary == @x.False';
  6017 
  6018 * HOLCF/IOA replaces old HOL/IOA;
  6019 
  6020 * HOLCF changes: derived all rules and arities
  6021   + axiomatic type classes instead of classes
  6022   + typedef instead of faking type definitions
  6023   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6024   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6025   + eliminated the types void, one, tr
  6026   + use unit lift and bool lift (with translations) instead of one and tr
  6027   + eliminated blift from Lift3.thy (use Def instead of blift)
  6028   all eliminated rules are derived as theorems --> no visible changes ;
  6029 
  6030 
  6031 *** ZF ***
  6032 
  6033 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6034 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6035 as ZF_cs addSIs [equalityI];
  6036 
  6037 
  6038 
  6039 New in Isabelle94-7 (November 96)
  6040 ---------------------------------
  6041 
  6042 * allowing negative levels (as offsets) in prlev and choplev;
  6043 
  6044 * super-linear speedup for large simplifications;
  6045 
  6046 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6047 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6048 FAIL); can suppress it using the command Delsimps (ex_simps @
  6049 all_simps); De Morgan laws are also now included, by default;
  6050 
  6051 * improved printing of ==>  :  ~:
  6052 
  6053 * new object-logic "Sequents" adds linear logic, while replacing LK
  6054 and Modal (thanks to Sara Kalvala);
  6055 
  6056 * HOL/Auth: correctness proofs for authentication protocols;
  6057 
  6058 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6059 examples on HOL/Auth);
  6060 
  6061 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6062 the rewriter and classical reasoner simultaneously;
  6063 
  6064 * function uresult no longer returns theorems in "standard" format;
  6065 regain previous version by: val uresult = standard o uresult;
  6066 
  6067 
  6068 
  6069 New in Isabelle94-6
  6070 -------------------
  6071 
  6072 * oracles -- these establish an interface between Isabelle and trusted
  6073 external reasoners, which may deliver results as theorems;
  6074 
  6075 * proof objects (in particular record all uses of oracles);
  6076 
  6077 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6078 
  6079 * "constdefs" section in theory files;
  6080 
  6081 * "primrec" section (HOL) no longer requires names;
  6082 
  6083 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6084 
  6085 
  6086 
  6087 New in Isabelle94-5
  6088 -------------------
  6089 
  6090 * reduced space requirements;
  6091 
  6092 * automatic HTML generation from theories;
  6093 
  6094 * theory files no longer require "..." (quotes) around most types;
  6095 
  6096 * new examples, including two proofs of the Church-Rosser theorem;
  6097 
  6098 * non-curried (1994) version of HOL is no longer distributed;
  6099 
  6100 
  6101 
  6102 New in Isabelle94-4
  6103 -------------------
  6104 
  6105 * greatly reduced space requirements;
  6106 
  6107 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6108 
  6109 * searchable theorem database (see the section "Retrieving theorems" on
  6110 page 8 of the Reference Manual);
  6111 
  6112 * new examples, including Grabczewski's monumental case study of the
  6113 Axiom of Choice;
  6114 
  6115 * The previous version of HOL renamed to Old_HOL;
  6116 
  6117 * The new version of HOL (previously called CHOL) uses a curried syntax
  6118 for functions.  Application looks like f a b instead of f(a,b);
  6119 
  6120 * Mutually recursive inductive definitions finally work in HOL;
  6121 
  6122 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6123 translates to the operator "split";
  6124 
  6125 
  6126 
  6127 New in Isabelle94-3
  6128 -------------------
  6129 
  6130 * new infix operator, addss, allowing the classical reasoner to
  6131 perform simplification at each step of its search.  Example:
  6132         fast_tac (cs addss ss)
  6133 
  6134 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6135 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6136 look like (a,b) instead of <a,b>;
  6137 
  6138 * PLEASE NOTE: CHOL will eventually replace HOL!
  6139 
  6140 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6141 It translates to the operator "split".  A new theory of integers is available;
  6142 
  6143 * In ZF, integer numerals now denote two's-complement binary integers.
  6144 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6145 
  6146 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6147 of the Axiom of Choice;
  6148 
  6149 
  6150 
  6151 New in Isabelle94-2
  6152 -------------------
  6153 
  6154 * Significantly faster resolution;
  6155 
  6156 * the different sections in a .thy file can now be mixed and repeated
  6157 freely;
  6158 
  6159 * Database of theorems for FOL, HOL and ZF.  New
  6160 commands including qed, qed_goal and bind_thm store theorems in the database.
  6161 
  6162 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6163 a given theory (thms_of), or find out what theory a theorem was proved in
  6164 (theory_of_thm);
  6165 
  6166 * Bugs fixed in the inductive definition and datatype packages;
  6167 
  6168 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6169 and HOL_dup_cs obsolete;
  6170 
  6171 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6172 have been removed;
  6173 
  6174 * Simpler definition of function space in ZF;
  6175 
  6176 * new results about cardinal and ordinal arithmetic in ZF;
  6177 
  6178 * 'subtype' facility in HOL for introducing new types as subsets of existing
  6179 types;
  6180 
  6181 :mode=text:wrap=hard:maxLineLen=72: