NEWS
author wenzelm
Thu Apr 02 15:07:00 2009 +0200 (2009-04-02)
changeset 30855 c22436e6d350
parent 30849 0e5ec6d2c1d9
child 30904 cc6a6047a10f
child 30930 11010e5f18f0
permissions -rw-r--r--
some more HOL-Nominal news;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in Isabelle2009 (April 2009)
     5 --------------------------------
     6 
     7 *** General ***
     8 
     9 * Simplified main Isabelle executables, with less surprises on
    10 case-insensitive file-systems (such as Mac OS).
    11 
    12   - The main Isabelle tool wrapper is now called "isabelle" instead of
    13     "isatool."
    14 
    15   - The former "isabelle" alias for "isabelle-process" has been
    16     removed (should rarely occur to regular users).
    17 
    18   - The former "isabelle-interface" and its alias "Isabelle" have been
    19     removed (interfaces are now regular Isabelle tools).
    20 
    21 Within scripts and make files, the Isabelle environment variables
    22 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    23 respectively.  (The latter are still available as legacy feature.)
    24 
    25 The old isabelle-interface wrapper could react in confusing ways if
    26 the interface was uninstalled or changed otherwise.  Individual
    27 interface tool configuration is now more explicit, see also the
    28 Isabelle system manual.  In particular, Proof General is now available
    29 via "isabelle emacs".
    30 
    31 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    32 purge installed copies of Isabelle executables and re-run "isabelle
    33 install -p ...", or use symlinks.
    34 
    35 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    36 old ~/isabelle, which was slightly non-standard and apt to cause
    37 surprises on case-insensitive file-systems (such as Mac OS).
    38 
    39 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    40 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    41 care is required when using older releases of Isabelle.  Note that
    42 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    43 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
    44 
    45 * Proofs of fully specified statements are run in parallel on
    46 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
    47 a regular 4-core machine, if the initial heap space is made reasonably
    48 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
    49 
    50 * The main reference manuals ("isar-ref", "implementation", and
    51 "system") have been updated and extended.  Formally checked references
    52 as hyperlinks are now available uniformly.
    53 
    54 
    55 *** Pure ***
    56 
    57 * Complete re-implementation of locales.  INCOMPATIBILITY in several
    58 respects.  The most important changes are listed below.  See the
    59 Tutorial on Locales ("locales" manual) for details.
    60 
    61 - In locale expressions, instantiation replaces renaming.  Parameters
    62 must be declared in a for clause.  To aid compatibility with previous
    63 parameter inheritance, in locale declarations, parameters that are not
    64 'touched' (instantiation position "_" or omitted) are implicitly added
    65 with their syntax at the beginning of the for clause.
    66 
    67 - Syntax from abbreviations and definitions in locales is available in
    68 locale expressions and context elements.  The latter is particularly
    69 useful in locale declarations.
    70 
    71 - More flexible mechanisms to qualify names generated by locale
    72 expressions.  Qualifiers (prefixes) may be specified in locale
    73 expressions, and can be marked as mandatory (syntax: "name!:") or
    74 optional (syntax "name?:").  The default depends for plain "name:"
    75 depends on the situation where a locale expression is used: in
    76 commands 'locale' and 'sublocale' prefixes are optional, in
    77 'interpretation' and 'interpret' prefixes are mandatory.  The old
    78 implicit qualifiers derived from the parameter names of a locale are
    79 no longer generated.
    80 
    81 - Command "sublocale l < e" replaces "interpretation l < e".  The
    82 instantiation clause in "interpretation" and "interpret" (square
    83 brackets) is no longer available.  Use locale expressions.
    84 
    85 - When converting proof scripts, mandatory qualifiers in
    86 'interpretation' and 'interpret' should be retained by default, even
    87 if this is an INCOMPATIBILITY compared to former behavior.  In the
    88 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
    89 in locale expressions range over a single locale instance only.
    90 
    91 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
    92 In existing theorem specifications replace the includes element by the
    93 respective context elements of the included locale, omitting those
    94 that are already present in the theorem specification.  Multiple
    95 assume elements of a locale should be replaced by a single one
    96 involving the locale predicate.  In the proof body, declarations (most
    97 notably theorems) may be regained by interpreting the respective
    98 locales in the proof context as required (command "interpret").
    99 
   100 If using "includes" in replacement of a target solely because the
   101 parameter types in the theorem are not as general as in the target,
   102 consider declaring a new locale with additional type constraints on
   103 the parameters (context element "constrains").
   104 
   105 - Discontinued "locale (open)".  INCOMPATIBILITY.
   106 
   107 - Locale interpretation commands no longer attempt to simplify goal.
   108 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   109 methods intro_locales and unfold_locales to clarify.
   110 
   111 - Locale interpretation commands no longer accept interpretation
   112 attributes.  INCOMPATIBILITY.
   113 
   114 * Class declaration: so-called "base sort" must not be given in import
   115 list any longer, but is inferred from the specification.  Particularly
   116 in HOL, write
   117 
   118     class foo = ...
   119 
   120 instead of
   121 
   122     class foo = type + ...
   123 
   124 * Class target: global versions of theorems stemming do not carry a
   125 parameter prefix any longer.  INCOMPATIBILITY.
   126 
   127 * Class 'instance' command no longer accepts attached definitions.
   128 INCOMPATIBILITY, use proper 'instantiation' target instead.
   129 
   130 * Recovered hiding of consts, which was accidentally broken in
   131 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   132 makes c inaccessible; consider using ``hide (open) const c'' instead.
   133 
   134 * Slightly more coherent Pure syntax, with updated documentation in
   135 isar-ref manual.  Removed locales meta_term_syntax and
   136 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   137 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   138 directly in regular applications.
   139 
   140 * There is a new syntactic category "float_const" for signed decimal
   141 fractions (e.g. 123.45 or -123.45).
   142 
   143 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   144 interface with 'setup' command instead.
   145 
   146 * Command 'local_setup' is similar to 'setup', but operates on a local
   147 theory context.
   148 
   149 * The 'axiomatization' command now only works within a global theory
   150 context.  INCOMPATIBILITY.
   151 
   152 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   153 hypotheses.  Sorts required in the course of reasoning need to be
   154 covered by the constraints in the initial statement, completed by the
   155 type instance information of the background theory.  Non-trivial sort
   156 hypotheses, which rarely occur in practice, may be specified via
   157 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   158 
   159   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   160 
   161 The result contains an implicit sort hypotheses as before --
   162 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   163 normalization.
   164 
   165 * Generalized Isar history, with support for linear undo, direct state
   166 addressing etc.
   167 
   168 * Changed defaults for unify configuration options:
   169 
   170   unify_trace_bound = 50 (formerly 25)
   171   unify_search_bound = 60 (formerly 30)
   172 
   173 * Different bookkeeping for code equations (INCOMPATIBILITY):
   174 
   175   a) On theory merge, the last set of code equations for a particular
   176      constant is taken (in accordance with the policy applied by other
   177      parts of the code generator framework).
   178 
   179   b) Code equations stemming from explicit declarations (e.g. code
   180      attribute) gain priority over default code equations stemming
   181      from definition, primrec, fun etc.
   182 
   183 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   184 
   185 * Unified theorem tables for both code code generators.  Thus [code
   186 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   187 
   188 * Command 'find_consts' searches for constants based on type and name
   189 patterns, e.g.
   190 
   191     find_consts "_ => bool"
   192 
   193 By default, matching is against subtypes, but it may be restricted to
   194 the whole type.  Searching by name is possible.  Multiple queries are
   195 conjunctive and queries may be negated by prefixing them with a
   196 hyphen:
   197 
   198     find_consts strict: "_ => bool" name: "Int" -"int => int"
   199 
   200 * New 'find_theorems' criterion "solves" matches theorems that
   201 directly solve the current goal (modulo higher-order unification).
   202 
   203 * Auto solve feature for main theorem statements: whenever a new goal
   204 is stated, "find_theorems solves" is called; any theorems that could
   205 solve the lemma directly are listed as part of the goal state.
   206 Cf. associated options in Proof General Isabelle settings menu,
   207 enabled by default, with reasonable timeout for pathological cases of
   208 higher-order unification.
   209 
   210 
   211 *** Document preparation ***
   212 
   213 * Antiquotation @{lemma} now imitates a regular terminal proof,
   214 demanding keyword 'by' and supporting the full method expression
   215 syntax just like the Isar command 'by'.
   216 
   217 
   218 *** HOL ***
   219 
   220 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   221 points Main and Complex_Main remain as before.
   222 
   223 * Logic image HOL-Plain provides a minimal HOL with the most important
   224 tools available (inductive, datatype, primrec, ...).  This facilitates
   225 experimentation and tool development.  Note that user applications
   226 (and library theories) should never refer to anything below theory
   227 Main, as before.
   228 
   229 * Logic image HOL-Main stops at theory Main, and thus facilitates
   230 experimentation due to shorter build times.
   231 
   232 * Logic image HOL-NSA contains theories of nonstandard analysis which
   233 were previously part of former HOL-Complex.  Entry point Hyperreal
   234 remains valid, but theories formerly using Complex_Main should now use
   235 new entry point Hypercomplex.
   236 
   237 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   238 Posix processes.  Avoids potentially expensive forking of the ML
   239 process.  New thread-based implementation also works on non-Unix
   240 platforms (Cygwin).  Provers are no longer hardwired, but defined
   241 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   242 commands are covered in the isar-ref manual.
   243 
   244 * Wrapper scripts for remote SystemOnTPTP service allows to use
   245 sledgehammer without local ATP installation (Vampire etc.). Other
   246 provers may be included via suitable ML wrappers, see also
   247 src/HOL/ATP_Linkup.thy.
   248 
   249 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   250 menu.
   251 
   252 * The metis method no longer fails because the theorem is too trivial
   253 (contains the empty clause).
   254 
   255 * The metis method now fails in the usual manner, rather than raising
   256 an exception, if it determines that it cannot prove the theorem.
   257 
   258 * Method "coherent" implements a prover for coherent logic (see also
   259 src/Tools/coherent.ML).
   260 
   261 * Constants "undefined" and "default" replace "arbitrary".  Usually
   262 "undefined" is the right choice to replace "arbitrary", though
   263 logically there is no difference.  INCOMPATIBILITY.
   264 
   265 * Command "value" now integrates different evaluation mechanisms.  The
   266 result of the first successful evaluation mechanism is printed.  In
   267 square brackets a particular named evaluation mechanisms may be
   268 specified (currently, [SML], [code] or [nbe]).  See further
   269 src/HOL/ex/Eval_Examples.thy.
   270 
   271 * Normalization by evaluation now allows non-leftlinear equations.
   272 Declare with attribute [code nbe].
   273 
   274 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   275 as the structured Isar versions "cases" and "induct", cf. the
   276 corresponding "cases" and "induct" attributes.  Mutual induction rules
   277 are now presented as a list of individual projections
   278 (e.g. foo_bar.inducts for types foo and bar); the old format with
   279 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   280 rare situations a different rule is selected --- notably nested tuple
   281 elimination instead of former prod.exhaust: use explicit (case_tac t
   282 rule: prod.exhaust) here.
   283 
   284 * Attributes "cases", "induct", "coinduct" support "del" option.
   285 
   286 * Removed fact "case_split_thm", which duplicates "case_split".
   287 
   288 * The option datatype has been moved to a new theory Option.  Renamed
   289 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   290 
   291 * New predicate "strict_mono" classifies strict functions on partial
   292 orders.  With strict functions on linear orders, reasoning about
   293 (in)equalities is facilitated by theorems "strict_mono_eq",
   294 "strict_mono_less_eq" and "strict_mono_less".
   295 
   296 * Some set operations are now proper qualified constants with
   297 authentic syntax.  INCOMPATIBILITY:
   298 
   299     op Int ~>   Set.Int
   300     op Un ~>    Set.Un
   301     INTER ~>    Set.INTER
   302     UNION ~>    Set.UNION
   303     Inter ~>    Set.Inter
   304     Union ~>    Set.Union
   305     {} ~>       Set.empty
   306     UNIV ~>     Set.UNIV
   307 
   308 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   309 theory Set.
   310 
   311 * Auxiliary class "itself" has disappeared -- classes without any
   312 parameter are treated as expected by the 'class' command.
   313 
   314 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   315 
   316 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   317 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   318 
   319 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   320 method "approximation".  It proves formulas on real values by using
   321 interval arithmetic.  In the formulas are also the transcendental
   322 functions sin, cos, tan, atan, ln, exp and the constant pi are
   323 allowed. For examples see
   324 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   325 
   326 * Theory "Reflection" now resides in HOL/Library.
   327 
   328 * Entry point to Word library now simply named "Word".
   329 INCOMPATIBILITY.
   330 
   331 * Made source layout more coherent with logical distribution
   332 structure:
   333 
   334     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   335     src/HOL/Library/Code_Message.thy ~> src/HOL/
   336     src/HOL/Library/GCD.thy ~> src/HOL/
   337     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   338     src/HOL/Library/Parity.thy ~> src/HOL/
   339     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   340     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   341     src/HOL/Real/Lubs.thy ~> src/HOL/
   342     src/HOL/Real/PReal.thy ~> src/HOL/
   343     src/HOL/Real/Rational.thy ~> src/HOL/
   344     src/HOL/Real/RComplete.thy ~> src/HOL/
   345     src/HOL/Real/RealDef.thy ~> src/HOL/
   346     src/HOL/Real/RealPow.thy ~> src/HOL/
   347     src/HOL/Real/Real.thy ~> src/HOL/
   348     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   349     src/HOL/Complex/Complex.thy ~> src/HOL/
   350     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   351     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   352     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   353     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   354     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   355     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   356     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   357     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   358     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   359     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   360     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   361     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   362     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   363     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   364     src/HOL/Real/Float ~> src/HOL/Library/
   365     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   366     src/HOL/Real/RealVector.thy ~> src/HOL/
   367 
   368     src/HOL/arith_data.ML ~> src/HOL/Tools
   369     src/HOL/hologic.ML ~> src/HOL/Tools
   370     src/HOL/simpdata.ML ~> src/HOL/Tools
   371     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   372     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   373     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   374     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   375     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   376     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   377     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   378 
   379     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   380     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   381     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   382     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   383     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   384     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   385 
   386 * If methods "eval" and "evaluation" encounter a structured proof
   387 state with !!/==>, only the conclusion is evaluated to True (if
   388 possible), avoiding strange error messages.
   389 
   390 * Method "sizechange" automates termination proofs using (a
   391 modification of) the size-change principle.  Requires SAT solver.  See
   392 src/HOL/ex/Termination.thy for examples.
   393 
   394 * Simplifier: simproc for let expressions now unfolds if bound
   395 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   396 
   397 * Method "arith": Linear arithmetic now ignores all inequalities when
   398 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   399 
   400 * New attribute "arith" for facts that should always be used
   401 automatically by arithmetic. It is intended to be used locally in
   402 proofs, e.g.
   403 
   404   assumes [arith]: "x > 0"
   405 
   406 Global usage is discouraged because of possible performance impact.
   407 
   408 * New classes "top" and "bot" with corresponding operations "top" and
   409 "bot" in theory Orderings; instantiation of class "complete_lattice"
   410 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   411 
   412 * Changed definition lemma "less_fun_def" in order to provide an
   413 instance for preorders on functions; use lemma "less_le" instead.
   414 INCOMPATIBILITY.
   415 
   416 * Theory Orderings: class "wellorder" moved here, with explicit
   417 induction rule "less_induct" as assumption.  For instantiation of
   418 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   419 INCOMPATIBILITY.
   420 
   421 * Theory Orderings: added class "preorder" as superclass of "order".
   422 INCOMPATIBILITY: Instantiation proofs for order, linorder
   423 etc. slightly changed.  Some theorems named order_class.* now named
   424 preorder_class.*.
   425 
   426 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   427 "diag" to "Id_on".
   428 
   429 * Theory Finite_Set: added a new fold combinator of type
   430 
   431   ('a => 'b => 'b) => 'b => 'a set => 'b
   432 
   433 Occasionally this is more convenient than the old fold combinator
   434 which is now defined in terms of the new one and renamed to
   435 fold_image.
   436 
   437 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   438 and "ring_simps" have been replaced by "algebra_simps" (which can be
   439 extended with further lemmas!).  At the moment both still exist but
   440 the former will disappear at some point.
   441 
   442 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   443 class recpower.  Type-specific simp rules for various recpower types
   444 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   445 
   446 rat_power_0    -> power_0
   447 rat_power_Suc  -> power_Suc
   448 realpow_0      -> power_0
   449 realpow_Suc    -> power_Suc
   450 complexpow_0   -> power_0
   451 complexpow_Suc -> power_Suc
   452 power_poly_0   -> power_0
   453 power_poly_Suc -> power_Suc
   454 
   455 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   456 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   457 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   458 of lemmas from Divides has been generalized from nat to class
   459 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   460 renames resulting from duplicate elimination:
   461 
   462     dvd_def_mod ~>          dvd_eq_mod_eq_0
   463     zero_dvd_iff ~>         dvd_0_left_iff
   464     dvd_0 ~>                dvd_0_right
   465     DIVISION_BY_ZERO_DIV ~> div_by_0
   466     DIVISION_BY_ZERO_MOD ~> mod_by_0
   467     mult_div ~>             div_mult_self2_is_id
   468     mult_mod ~>             mod_mult_self2_is_0
   469 
   470 * Theory IntDiv: removed many lemmas that are instances of class-based
   471 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   472 rename old lemmas as follows:
   473 
   474 dvd_diff               -> nat_dvd_diff
   475 dvd_zminus_iff         -> dvd_minus_iff
   476 mod_add1_eq            -> mod_add_eq
   477 mod_mult1_eq           -> mod_mult_right_eq
   478 mod_mult1_eq'          -> mod_mult_left_eq
   479 mod_mult_distrib_mod   -> mod_mult_eq
   480 nat_mod_add_left_eq    -> mod_add_left_eq
   481 nat_mod_add_right_eq   -> mod_add_right_eq
   482 nat_mod_div_trivial    -> mod_div_trivial
   483 nat_mod_mod_trivial    -> mod_mod_trivial
   484 zdiv_zadd_self1        -> div_add_self1
   485 zdiv_zadd_self2        -> div_add_self2
   486 zdiv_zmult_self1       -> div_mult_self2_is_id
   487 zdiv_zmult_self2       -> div_mult_self1_is_id
   488 zdvd_triv_left         -> dvd_triv_left
   489 zdvd_triv_right        -> dvd_triv_right
   490 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   491 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   492 zmod_zadd_left_eq      -> mod_add_left_eq
   493 zmod_zadd_right_eq     -> mod_add_right_eq
   494 zmod_zadd_self1        -> mod_add_self1
   495 zmod_zadd_self2        -> mod_add_self2
   496 zmod_zadd1_eq          -> mod_add_eq
   497 zmod_zdiff1_eq         -> mod_diff_eq
   498 zmod_zdvd_zmod         -> mod_mod_cancel
   499 zmod_zmod_cancel       -> mod_mod_cancel
   500 zmod_zmult_self1       -> mod_mult_self2_is_0
   501 zmod_zmult_self2       -> mod_mult_self1_is_0
   502 zmod_1                 -> mod_by_1
   503 zdiv_1                 -> div_by_1
   504 zdvd_abs1              -> abs_dvd_iff
   505 zdvd_abs2              -> dvd_abs_iff
   506 zdvd_refl              -> dvd_refl
   507 zdvd_trans             -> dvd_trans
   508 zdvd_zadd              -> dvd_add
   509 zdvd_zdiff             -> dvd_diff
   510 zdvd_zminus_iff        -> dvd_minus_iff
   511 zdvd_zminus2_iff       -> minus_dvd_iff
   512 zdvd_zmultD            -> dvd_mult_right
   513 zdvd_zmultD2           -> dvd_mult_left
   514 zdvd_zmult_mono        -> mult_dvd_mono
   515 zdvd_0_right           -> dvd_0_right
   516 zdvd_0_left            -> dvd_0_left_iff
   517 zdvd_1_left            -> one_dvd
   518 zminus_dvd_iff         -> minus_dvd_iff
   519 
   520 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   521 
   522 * The real numbers offer decimal input syntax: 12.34 is translated
   523 into 1234/10^2. This translation is not reversed upon output.
   524 
   525 * Theory Library/Polynomial defines an abstract type 'a poly of
   526 univariate polynomials with coefficients of type 'a.  In addition to
   527 the standard ring operations, it also supports div and mod.  Code
   528 generation is also supported, using list-style constructors.
   529 
   530 * Theory Library/Inner_Product defines a class of real_inner for real
   531 inner product spaces, with an overloaded operation inner :: 'a => 'a
   532 => real.  Class real_inner is a subclass of real_normed_vector from
   533 theory RealVector.
   534 
   535 * Theory Library/Product_Vector provides instances for the product
   536 type 'a * 'b of several classes from RealVector and Inner_Product.
   537 Definitions of addition, subtraction, scalar multiplication, norms,
   538 and inner products are included.
   539 
   540 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   541 addition to the field operations, numerals and case syntax are also
   542 supported.
   543 
   544 * Theory Library/Diagonalize provides constructive version of Cantor's
   545 first diagonalization argument.
   546 
   547 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   548 zlcm (for int); carried together from various gcd/lcm developements in
   549 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   550 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   551 may recover tupled syntax as follows:
   552 
   553     hide (open) const gcd
   554     abbreviation gcd where
   555       "gcd == (%(a, b). GCD.gcd a b)"
   556     notation (output)
   557       GCD.gcd ("gcd '(_, _')")
   558 
   559 The same works for lcm, zgcd, zlcm.
   560 
   561 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   562 instantiations for algebraic structures.  Removed some duplicate
   563 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   564 
   565 * ML antiquotation @{code} takes a constant as argument and generates
   566 corresponding code in background and inserts name of the corresponding
   567 resulting ML value/function/datatype constructor binding in place.
   568 All occurrences of @{code} with a single ML block are generated
   569 simultaneously.  Provides a generic and safe interface for
   570 instrumentalizing code generation.  See
   571 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   572 In future you ought to refrain from ad-hoc compiling generated SML
   573 code on the ML toplevel.  Note that (for technical reasons) @{code}
   574 cannot refer to constants for which user-defined serializations are
   575 set.  Refer to the corresponding ML counterpart directly in that
   576 cases.
   577 
   578 * Command 'rep_datatype': instead of theorem names the command now
   579 takes a list of terms denoting the constructors of the type to be
   580 represented as datatype.  The characteristic theorems have to be
   581 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   582 have disappeared in favour of existing ones:
   583 
   584     unit_induct                 ~> unit.induct
   585     prod_induct                 ~> prod.induct
   586     sum_induct                  ~> sum.induct
   587     Suc_Suc_eq                  ~> nat.inject
   588     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   589 
   590 
   591 *** HOL-Algebra ***
   592 
   593 * New locales for orders and lattices where the equivalence relation
   594 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   595 locales use a record structure with field eq for the equivalence.
   596 
   597 * New theory of factorial domains.
   598 
   599 * Units_l_inv and Units_r_inv are now simp rules by default.
   600 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   601 and/or r_inv will now also require deletion of these lemmas.
   602 
   603 * Renamed the following theorems, INCOMPATIBILITY:
   604 
   605 UpperD ~> Upper_memD
   606 LowerD ~> Lower_memD
   607 least_carrier ~> least_closed
   608 greatest_carrier ~> greatest_closed
   609 greatest_Lower_above ~> greatest_Lower_below
   610 one_zero ~> carrier_one_zero
   611 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   612 
   613 
   614 *** HOL-Nominal ***
   615 
   616 * Nominal datatypes can now contain type-variables.
   617 
   618 * Commands 'nominal_inductive' and 'equivariance' work with local
   619 theory targets.
   620 
   621 * Nominal primrec can now works with local theory targets and its
   622 specification syntax now conforms to the general format as seen in
   623 'inductive' etc.
   624 
   625 * Method "perm_simp" honours the standard simplifier attributes
   626 (no_asm), (no_asm_use) etc.
   627 
   628 * The new predicate #* is defined like freshness, except that on the
   629 left hand side can be a set or list of atoms.
   630 
   631 * Experimental command 'nominal_inductive2' derives strong induction
   632 principles for inductive definitions.  In contrast to
   633 'nominal_inductive', which can only deal with a fixed number of
   634 binders, it can deal with arbitrary expressions standing for sets of
   635 atoms to be avoided.  The only inductive definition we have at the
   636 moment that needs this generalisation is the typing rule for Lets in
   637 the algorithm W:
   638 
   639  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   640  -----------------------------------------------------------------
   641          Gamma |- Let x be t1 in t2 : T2
   642 
   643 In this rule one wants to avoid all the binders that are introduced by
   644 "close Gamma T1".  We are looking for other examples where this
   645 feature might be useful.  Please let us know.
   646 
   647 
   648 *** HOLCF ***
   649 
   650 * Reimplemented the simplification procedure for proving continuity
   651 subgoals.  The new simproc is extensible; users can declare additional
   652 continuity introduction rules with the attribute [cont2cont].
   653 
   654 * The continuity simproc now uses a different introduction rule for
   655 solving continuity subgoals on terms with lambda abstractions.  In
   656 some rare cases the new simproc may fail to solve subgoals that the
   657 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   658 Potential INCOMPATIBILITY.
   659 
   660 * Command 'fixrec': specification syntax now conforms to the general
   661 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   662 examples.  INCOMPATIBILITY.
   663 
   664 
   665 *** ZF ***
   666 
   667 * Proof of Zorn's Lemma for partial orders.
   668 
   669 
   670 *** ML ***
   671 
   672 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   673 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   674 depends on multithreading, so timouts will not work before Poly/ML
   675 5.2.1!
   676 
   677 * High-level support for concurrent ML programming, see
   678 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   679 particularly convenient to organize independent functional
   680 computations.  The concept of "synchronized variables" provides a
   681 higher-order interface for components with shared state, avoiding the
   682 delicate details of mutexes and condition variables.  (Requires
   683 Poly/ML 5.2.1 or later.)
   684 
   685 * ML bindings produced via Isar commands are stored within the Isar
   686 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   687 become thread-safe and work with undo as expected (concerning
   688 top-level bindings, not side-effects on global references).
   689 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   690 compiler at runtime; really global bindings need to be given outside a
   691 theory.  (Requires Poly/ML 5.2 or later.)
   692 
   693 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   694 context.  Top-level ML bindings are stored within the proof context in
   695 a purely sequential fashion, disregarding the nested proof structure.
   696 ML bindings introduced by 'ML_prf' are discarded at the end of the
   697 proof.  (Requires Poly/ML 5.2 or later.)
   698 
   699 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   700 and Method.setup, as well as Isar commands 'attribute_setup' and
   701 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   702 existing code accordingly, or use plain 'setup' together with old
   703 Method.add_method.
   704 
   705 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   706 to 'a -> thm, while results are always tagged with an authentic oracle
   707 name.  The Isar command 'oracle' is now polymorphic, no argument type
   708 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   709 accordingly.  Note that extra performance may be gained by producing
   710 the cterm carefully, avoiding slow Thm.cterm_of.
   711 
   712 * Simplified interface for defining document antiquotations via
   713 ThyOutput.antiquotation, ThyOutput.output, and optionally
   714 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   715 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   716 examples.
   717 
   718 * More systematic treatment of long names, abstract name bindings, and
   719 name space operations.  Basic operations on qualified names have been
   720 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   721 Long_Name.append.  Old type bstring has been mostly replaced by
   722 abstract type binding (see structure Binding), which supports precise
   723 qualification by packages and local theory targets, as well as proper
   724 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   725 bstring values into Binding.name, or better pass through abstract
   726 bindings everywhere.  See further src/Pure/General/long_name.ML,
   727 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   728 
   729 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   730 LocalTheory.note etc.) now refer to the *full* internal name, not the
   731 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   732 
   733 * Disposed old type and term read functions (Sign.read_def_typ,
   734 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   735 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   736 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   737 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   738 resort for legacy applications.
   739 
   740 * Disposed old declarations, tactics, tactic combinators that refer to
   741 the simpset or claset of an implicit theory (such as Addsimps,
   742 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   743 embedded ML text, or local_simpset_of with a proper context passed as
   744 explicit runtime argument.
   745 
   746 * Rules and tactics that read instantiations (read_instantiate,
   747 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   748 context, which is required for parsing and type-checking.  Moreover,
   749 the variables are specified as plain indexnames, not string encodings
   750 thereof.  INCOMPATIBILITY.
   751 
   752 * Generic Toplevel.add_hook interface allows to analyze the result of
   753 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   754 for theorem dependency output of transactions resulting in a new
   755 theory state.
   756 
   757 * ML antiquotations: block-structured compilation context indicated by
   758 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   759 
   760   @{binding name}                         - basic name binding
   761   @{let ?pat = term}                      - term abbreviation (HO matching)
   762   @{note name = fact}                     - fact abbreviation
   763   @{thm fact}                             - singleton fact (with attributes)
   764   @{thms fact}                            - general fact (with attributes)
   765   @{lemma prop by method}                 - singleton goal
   766   @{lemma prop by meth1 meth2}            - singleton goal
   767   @{lemma prop1 ... propN by method}      - general goal
   768   @{lemma prop1 ... propN by meth1 meth2} - general goal
   769   @{lemma (open) ...}                     - open derivation
   770 
   771 
   772 *** System ***
   773 
   774 * The Isabelle "emacs" tool provides a specific interface to invoke
   775 Proof General / Emacs, with more explicit failure if that is not
   776 installed (the old isabelle-interface script silently falls back on
   777 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   778 installation location of the Proof General distribution.
   779 
   780 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   781 the Isabelle process into a JVM/Scala application.  See
   782 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   783 process wrapper has been discontinued.)
   784 
   785 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   786 
   787 * Various status messages (with exact source position information) are
   788 emitted, if proper markup print mode is enabled.  This allows
   789 user-interface components to provide detailed feedback on internal
   790 prover operations.
   791 
   792 
   793 
   794 New in Isabelle2008 (June 2008)
   795 -------------------------------
   796 
   797 *** General ***
   798 
   799 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   800 and updated, with formally checked references as hyperlinks.
   801 
   802 * Theory loader: use_thy (and similar operations) no longer set the
   803 implicit ML context, which was occasionally hard to predict and in
   804 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   805 provides a proper context already.
   806 
   807 * Theory loader: old-style ML proof scripts being *attached* to a thy
   808 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   809 'use' within a theory file will do the job.
   810 
   811 * Name space merge now observes canonical order, i.e. the second space
   812 is inserted into the first one, while existing entries in the first
   813 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   814 swap theory imports.
   815 
   816 * Syntax: symbol \<chi> is now considered a letter.  Potential
   817 INCOMPATIBILITY in identifier syntax etc.
   818 
   819 * Outer syntax: string tokens no longer admit escaped white space,
   820 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   821 white space without escapes.
   822 
   823 * Outer syntax: string tokens may contain arbitrary character codes
   824 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   825 "foo_bar".
   826 
   827 
   828 *** Pure ***
   829 
   830 * Context-dependent token translations.  Default setup reverts locally
   831 fixed variables, and adds hilite markup for undeclared frees.
   832 
   833 * Unused theorems can be found using the new command 'unused_thms'.
   834 There are three ways of invoking it:
   835 
   836 (1) unused_thms
   837      Only finds unused theorems in the current theory.
   838 
   839 (2) unused_thms thy_1 ... thy_n -
   840      Finds unused theorems in the current theory and all of its ancestors,
   841      excluding the theories thy_1 ... thy_n and all of their ancestors.
   842 
   843 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   844      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   845      their ancestors, excluding the theories thy_1 ... thy_n and all of
   846      their ancestors.
   847 
   848 In order to increase the readability of the list produced by
   849 unused_thms, theorems that have been created by a particular instance
   850 of a theory command such as 'inductive' or 'function' are considered
   851 to belong to the same "group", meaning that if at least one theorem in
   852 this group is used, the other theorems in the same group are no longer
   853 reported as unused.  Moreover, if all theorems in the group are
   854 unused, only one theorem in the group is displayed.
   855 
   856 Note that proof objects have to be switched on in order for
   857 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   858 usually the case when using Proof General with the default settings).
   859 
   860 * Authentic naming of facts disallows ad-hoc overwriting of previous
   861 theorems within the same name space.  INCOMPATIBILITY, need to remove
   862 duplicate fact bindings, or even accidental fact duplications.  Note
   863 that tools may maintain dynamically scoped facts systematically, using
   864 PureThy.add_thms_dynamic.
   865 
   866 * Command 'hide' now allows to hide from "fact" name space as well.
   867 
   868 * Eliminated destructive theorem database, simpset, claset, and
   869 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   870 update of theories within ML code.
   871 
   872 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   873 INCOMPATIBILITY, object-logics depending on former Pure require
   874 additional setup PureThy.old_appl_syntax_setup; object-logics
   875 depending on former CPure need to refer to Pure.
   876 
   877 * Commands 'use' and 'ML' are now purely functional, operating on
   878 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   879 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   880 INCOMPATIBILITY.
   881 
   882 * Command 'setup': discontinued implicit version with ML reference.
   883 
   884 * Instantiation target allows for simultaneous specification of class
   885 instance operations together with an instantiation proof.
   886 Type-checking phase allows to refer to class operations uniformly.
   887 See src/HOL/Complex/Complex.thy for an Isar example and
   888 src/HOL/Library/Eval.thy for an ML example.
   889 
   890 * Indexing of literal facts: be more serious about including only
   891 facts from the visible specification/proof context, but not the
   892 background context (locale etc.).  Affects `prop` notation and method
   893 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   894 situations.
   895 
   896 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   897 "(open)" option, which used to expose internal bound variables to the
   898 proof text.
   899 
   900 * Isar statements: removed obsolete case "rule_context".
   901 INCOMPATIBILITY, better use explicit fixes/assumes.
   902 
   903 * Locale proofs: default proof step now includes 'unfold_locales';
   904 hence 'proof' without argument may be used to unfold locale
   905 predicates.
   906 
   907 
   908 *** Document preparation ***
   909 
   910 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   911 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   912 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   913 spot); renamed link color from "darkblue" to "linkcolor" (default
   914 value unchanged, can be redefined via \definecolor); no longer sets
   915 "a4paper" option (unnecessary or even intrusive).
   916 
   917 * Antiquotation @{lemma A method} proves proposition A by the given
   918 method (either a method name or a method name plus (optional) method
   919 arguments in parentheses) and prints A just like @{prop A}.
   920 
   921 
   922 *** HOL ***
   923 
   924 * New primrec package.  Specification syntax conforms in style to
   925 definition/function/....  No separate induction rule is provided.  The
   926 "primrec" command distinguishes old-style and new-style specifications
   927 by syntax.  The former primrec package is now named OldPrimrecPackage.
   928 When adjusting theories, beware: constants stemming from new-style
   929 primrec specifications have authentic syntax.
   930 
   931 * Metis prover is now an order of magnitude faster, and also works
   932 with multithreading.
   933 
   934 * Metis: the maximum number of clauses that can be produced from a
   935 theorem is now given by the attribute max_clauses.  Theorems that
   936 exceed this number are ignored, with a warning printed.
   937 
   938 * Sledgehammer no longer produces structured proofs by default. To
   939 enable, declare [[sledgehammer_full = true]].  Attributes
   940 reconstruction_modulus, reconstruction_sorts renamed
   941 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   942 
   943 * Method "induct_scheme" derives user-specified induction rules
   944 from well-founded induction and completeness of patterns. This factors
   945 out some operations that are done internally by the function package
   946 and makes them available separately.  See
   947 src/HOL/ex/Induction_Scheme.thy for examples.
   948 
   949 * More flexible generation of measure functions for termination
   950 proofs: Measure functions can be declared by proving a rule of the
   951 form "is_measure f" and giving it the [measure_function] attribute.
   952 The "is_measure" predicate is logically meaningless (always true), and
   953 just guides the heuristic.  To find suitable measure functions, the
   954 termination prover sets up the goal "is_measure ?f" of the appropriate
   955 type and generates all solutions by prolog-style backwards proof using
   956 the declared rules.
   957 
   958 This setup also deals with rules like 
   959 
   960   "is_measure f ==> is_measure (list_size f)"
   961 
   962 which accommodates nested datatypes that recurse through lists.
   963 Similar rules are predeclared for products and option types.
   964 
   965 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   966 
   967   INCOMPATIBILITIES:
   968 
   969   - Definitions of overloaded constants on sets have to be replaced by
   970     definitions on => and bool.
   971 
   972   - Some definitions of overloaded operators on sets can now be proved
   973     using the definitions of the operators on => and bool.  Therefore,
   974     the following theorems have been renamed:
   975 
   976       subset_def   -> subset_eq
   977       psubset_def  -> psubset_eq
   978       set_diff_def -> set_diff_eq
   979       Compl_def    -> Compl_eq
   980       Sup_set_def  -> Sup_set_eq
   981       Inf_set_def  -> Inf_set_eq
   982       sup_set_def  -> sup_set_eq
   983       inf_set_def  -> inf_set_eq
   984 
   985   - Due to the incompleteness of the HO unification algorithm, some
   986     rules such as subst may require manual instantiation, if some of
   987     the unknowns in the rule is a set.
   988 
   989   - Higher order unification and forward proofs:
   990     The proof pattern
   991 
   992       have "P (S::'a set)" <...>
   993       then have "EX S. P S" ..
   994 
   995     no longer works (due to the incompleteness of the HO unification
   996     algorithm) and must be replaced by the pattern
   997 
   998       have "EX S. P S"
   999       proof
  1000         show "P S" <...>
  1001       qed
  1002 
  1003   - Calculational reasoning with subst (or similar rules):
  1004     The proof pattern
  1005 
  1006       have "P (S::'a set)" <...>
  1007       also have "S = T" <...>
  1008       finally have "P T" .
  1009 
  1010     no longer works (for similar reasons as the previous example) and
  1011     must be replaced by something like
  1012 
  1013       have "P (S::'a set)" <...>
  1014       moreover have "S = T" <...>
  1015       ultimately have "P T" by simp
  1016 
  1017   - Tactics or packages written in ML code:
  1018     Code performing pattern matching on types via
  1019 
  1020       Type ("set", [T]) => ...
  1021 
  1022     must be rewritten. Moreover, functions like strip_type or
  1023     binder_types no longer return the right value when applied to a
  1024     type of the form
  1025 
  1026       T1 => ... => Tn => U => bool
  1027 
  1028     rather than
  1029 
  1030       T1 => ... => Tn => U set
  1031 
  1032 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1033 Wellfounded_Relations to theory Wellfounded.
  1034 
  1035 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1036 
  1037 * Class finite no longer treats UNIV as class parameter.  Use class
  1038 enum from theory Library/Enum instead to achieve a similar effect.
  1039 INCOMPATIBILITY.
  1040 
  1041 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1042 and "Cons".  INCOMPATIBILITY.
  1043 
  1044 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1045 Potential INCOMPATIBILITY.
  1046 
  1047 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1048 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1049 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1050 
  1051 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1052 the same name in theory Orderings:
  1053 
  1054   less_trans
  1055   less_linear
  1056   le_imp_less_or_eq
  1057   le_less_trans
  1058   less_le_trans
  1059   less_not_sym
  1060   less_asym
  1061 
  1062 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1063 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1064 and different variable names.
  1065 
  1066 * Library/Option_ord.thy: Canonical order on option type.
  1067 
  1068 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1069 finite maps.
  1070 
  1071 * Library/Countable.thy: Type class for countable types.
  1072 
  1073 * Theory Int: The representation of numerals has changed.  The infix
  1074 operator BIT and the bit datatype with constructors B0 and B1 have
  1075 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1076 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1077 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1078 accordingly.
  1079 
  1080 * Theory Nat: definition of <= and < on natural numbers no longer
  1081 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1082 le_def and less_def have disappeared.  Consider lemmas not_less
  1083 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1084 
  1085 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1086 (whose purpose mainly is for various fold_set functionals) have been
  1087 abandoned in favor of the existing algebraic classes
  1088 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1089 lower_semilattice (resp. upper_semilattice) and linorder.
  1090 INCOMPATIBILITY.
  1091 
  1092 * Theory Transitive_Closure: induct and cases rules now declare proper
  1093 case_names ("base" and "step").  INCOMPATIBILITY.
  1094 
  1095 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1096 lattices.  The form set-specific version is available as
  1097 Inductive.lfp_ordinal_induct_set.
  1098 
  1099 * Renamed theorems "power.simps" to "power_int.simps".
  1100 INCOMPATIBILITY.
  1101 
  1102 * Class semiring_div provides basic abstract properties of semirings
  1103 with division and modulo operations.  Subsumes former class dvd_mod.
  1104 
  1105 * Merged theories IntDef, Numeral and IntArith into unified theory
  1106 Int.  INCOMPATIBILITY.
  1107 
  1108 * Theory Library/Code_Index: type "index" now represents natural
  1109 numbers rather than integers.  INCOMPATIBILITY.
  1110 
  1111 * New class "uminus" with operation "uminus" (split of from class
  1112 "minus" which now only has operation "minus", binary).
  1113 INCOMPATIBILITY.
  1114 
  1115 * Constants "card", "internal_split", "option_map" now with authentic
  1116 syntax.  INCOMPATIBILITY.
  1117 
  1118 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1119 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1120 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1121 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1122 Sup_set_def, le_def, less_def, option_map_def now with object
  1123 equality.  INCOMPATIBILITY.
  1124 
  1125 * Records. Removed K_record, and replaced it by pure lambda term
  1126 %x. c. The simplifier setup is now more robust against eta expansion.
  1127 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1128 
  1129 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1130 
  1131 * Library/ListVector: new theory of arithmetic vector operations.
  1132 
  1133 * Library/Order_Relation: new theory of various orderings as sets of
  1134 pairs.  Defines preorders, partial orders, linear orders and
  1135 well-orders on sets and on types.
  1136 
  1137 
  1138 *** ZF ***
  1139 
  1140 * Renamed some theories to allow to loading both ZF and HOL in the
  1141 same session:
  1142 
  1143   Datatype  -> Datatype_ZF
  1144   Inductive -> Inductive_ZF
  1145   Int       -> Int_ZF
  1146   IntDiv    -> IntDiv_ZF
  1147   Nat       -> Nat_ZF
  1148   List      -> List_ZF
  1149   Main      -> Main_ZF
  1150 
  1151 INCOMPATIBILITY: ZF theories that import individual theories below
  1152 Main might need to be adapted.  Regular theory Main is still
  1153 available, as trivial extension of Main_ZF.
  1154 
  1155 
  1156 *** ML ***
  1157 
  1158 * ML within Isar: antiquotation @{const name} or @{const
  1159 name(typargs)} produces statically-checked Const term.
  1160 
  1161 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1162 (of the same name).  Removed obsolete print command.
  1163 
  1164 * Removed obsolete "use_legacy_bindings" function.
  1165 
  1166 * The ``print mode'' is now a thread-local value derived from a global
  1167 template (the former print_mode reference), thus access becomes
  1168 non-critical.  The global print_mode reference is for session
  1169 management only; user-code should use print_mode_value,
  1170 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1171 
  1172 * Functions system/system_out provide a robust way to invoke external
  1173 shell commands, with propagation of interrupts (requires Poly/ML
  1174 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1175 
  1176 
  1177 *** System ***
  1178 
  1179 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1180 in accordance with Proof General 3.7, which prefers GNU emacs.
  1181 
  1182 * isatool tty runs Isabelle process with plain tty interaction;
  1183 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1184 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1185 
  1186 * isatool browser now works with Cygwin as well, using general
  1187 "javapath" function defined in Isabelle process environment.
  1188 
  1189 * YXML notation provides a simple and efficient alternative to
  1190 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1191 isatool yxml as described in the Isabelle system manual.
  1192 
  1193 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1194 provides general wrapper for managing an Isabelle process in a robust
  1195 fashion, with ``cooked'' output from stdin/stderr.
  1196 
  1197 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1198 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1199 
  1200 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1201 way of changing the user's settings is via
  1202 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1203 script.
  1204 
  1205 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1206 cores of the underlying machine, which is a good starting point for
  1207 optimal performance tuning.  The corresponding usedir option -M allows
  1208 "max" as an alias for "0".  WARNING: does not work on certain versions
  1209 of Mac OS (with Poly/ML 5.1).
  1210 
  1211 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1212 adverse effect of Isabelle flooding interactive front-ends (notably
  1213 ProofGeneral / XEmacs).
  1214 
  1215 
  1216 
  1217 New in Isabelle2007 (November 2007)
  1218 -----------------------------------
  1219 
  1220 *** General ***
  1221 
  1222 * More uniform information about legacy features, notably a
  1223 warning/error of "Legacy feature: ...", depending on the state of the
  1224 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1225 legacy features will disappear eventually.
  1226 
  1227 * Theory syntax: the header format ``theory A = B + C:'' has been
  1228 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1229 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1230 
  1231 * Theory syntax: the old non-Isar theory file format has been
  1232 discontinued altogether.  Note that ML proof scripts may still be used
  1233 with Isar theories; migration is usually quite simple with the ML
  1234 function use_legacy_bindings.  INCOMPATIBILITY.
  1235 
  1236 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1237 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1238 quotes.
  1239 
  1240 * Theory loader: be more serious about observing the static theory
  1241 header specifications (including optional directories), but not the
  1242 accidental file locations of previously successful loads.  The strict
  1243 update policy of former update_thy is now already performed by
  1244 use_thy, so the former has been removed; use_thys updates several
  1245 theories simultaneously, just as 'imports' within a theory header
  1246 specification, but without merging the results.  Potential
  1247 INCOMPATIBILITY: may need to refine theory headers and commands
  1248 ROOT.ML which depend on load order.
  1249 
  1250 * Theory loader: optional support for content-based file
  1251 identification, instead of the traditional scheme of full physical
  1252 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1253 (cf. the system manual).  The new scheme allows to work with
  1254 non-finished theories in persistent session images, such that source
  1255 files may be moved later on without requiring reloads.
  1256 
  1257 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1258 file (with the same base name as the theory) are considered a legacy
  1259 feature, which will disappear eventually. Even now, the theory loader
  1260 no longer maintains dependencies on such files.
  1261 
  1262 * Syntax: the scope for resolving ambiguities via type-inference is
  1263 now limited to individual terms, instead of whole simultaneous
  1264 specifications as before. This greatly reduces the complexity of the
  1265 syntax module and improves flexibility by separating parsing and
  1266 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1267 'fixes' etc.) are required in rare situations.
  1268 
  1269 * Syntax: constants introduced by new-style packages ('definition',
  1270 'abbreviation' etc.) are passed through the syntax module in
  1271 ``authentic mode''. This means that associated mixfix annotations
  1272 really stick to such constants, independently of potential name space
  1273 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1274 trees are represented slightly differently, may need to adapt syntax
  1275 translations accordingly. Use CONST marker in 'translations' and
  1276 @{const_syntax} antiquotation in 'parse_translation' etc.
  1277 
  1278 * Legacy goal package: reduced interface to the bare minimum required
  1279 to keep existing proof scripts running.  Most other user-level
  1280 functions are now part of the OldGoals structure, which is *not* open
  1281 by default (consider isatool expandshort before open OldGoals).
  1282 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1283 these tend to cause confusion about the actual goal (!) context being
  1284 used here, which is not necessarily the same as the_context().
  1285 
  1286 * Command 'find_theorems': supports "*" wild-card in "name:"
  1287 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1288 support a specific search form (see ProofGeneral/CHANGES).
  1289 
  1290 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1291 by default, which means that "prems" (and also "fixed variables") are
  1292 suppressed from proof state output.  Note that the ProofGeneral
  1293 settings mechanism allows to change and save options persistently, but
  1294 older versions of Isabelle will fail to start up if a negative prems
  1295 limit is imposed.
  1296 
  1297 * Local theory targets may be specified by non-nested blocks of
  1298 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1299 contain definitions, theorems etc., including any derived mechanism
  1300 that has been implemented on top of these primitives.  This concept
  1301 generalizes the existing ``theorem (in ...)'' towards more versatility
  1302 and scalability.
  1303 
  1304 * Proof General interface: proper undo of final 'end' command;
  1305 discontinued Isabelle/classic mode (ML proof scripts).
  1306 
  1307 
  1308 *** Document preparation ***
  1309 
  1310 * Added antiquotation @{theory name} which prints the given name,
  1311 after checking that it refers to a valid ancestor theory in the
  1312 current context.
  1313 
  1314 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1315 check the given source text as ML type/structure, printing verbatim.
  1316 
  1317 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1318 "c args == rhs" given in the current context.  (Any number of
  1319 arguments may be given on the LHS.)
  1320 
  1321 
  1322 *** Pure ***
  1323 
  1324 * The 'class' package offers a combination of axclass and locale to
  1325 achieve Haskell-like type classes in Isabelle.  Definitions and
  1326 theorems within a class context produce both relative results (with
  1327 implicit parameters according to the locale context), and polymorphic
  1328 constants with qualified polymorphism (according to the class
  1329 context).  Within the body context of a 'class' target, a separate
  1330 syntax layer ("user space type system") takes care of converting
  1331 between global polymorphic consts and internal locale representation.
  1332 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1333 "isatool doc classes" provides a tutorial.
  1334 
  1335 * Generic code generator framework allows to generate executable
  1336 code for ML and Haskell (including Isabelle classes).  A short usage
  1337 sketch:
  1338 
  1339     internal compilation:
  1340         export_code <list of constants (term syntax)> in SML
  1341     writing SML code to a file:
  1342         export_code <list of constants (term syntax)> in SML <filename>
  1343     writing OCaml code to a file:
  1344         export_code <list of constants (term syntax)> in OCaml <filename>
  1345     writing Haskell code to a bunch of files:
  1346         export_code <list of constants (term syntax)> in Haskell <filename>
  1347 
  1348     evaluating closed propositions to True/False using code generation:
  1349         method ``eval''
  1350 
  1351 Reasonable default setup of framework in HOL.
  1352 
  1353 Theorem attributs for selecting and transforming function equations theorems:
  1354 
  1355     [code fun]:        select a theorem as function equation for a specific constant
  1356     [code fun del]:    deselect a theorem as function equation for a specific constant
  1357     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1358     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1359 
  1360 User-defined serializations (target in {SML, OCaml, Haskell}):
  1361 
  1362     code_const <and-list of constants (term syntax)>
  1363       {(target) <and-list of const target syntax>}+
  1364 
  1365     code_type <and-list of type constructors>
  1366       {(target) <and-list of type target syntax>}+
  1367 
  1368     code_instance <and-list of instances>
  1369       {(target)}+
  1370         where instance ::= <type constructor> :: <class>
  1371 
  1372     code_class <and_list of classes>
  1373       {(target) <and-list of class target syntax>}+
  1374         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1375 
  1376 code_instance and code_class only are effective to target Haskell.
  1377 
  1378 For example usage see src/HOL/ex/Codegenerator.thy and
  1379 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1380 generation from Isabelle/HOL theories is available via "isatool doc
  1381 codegen".
  1382 
  1383 * Code generator: consts in 'consts_code' Isar commands are now
  1384 referred to by usual term syntax (including optional type
  1385 annotations).
  1386 
  1387 * Command 'no_translations' removes translation rules from theory
  1388 syntax.
  1389 
  1390 * Overloaded definitions are now actually checked for acyclic
  1391 dependencies.  The overloading scheme is slightly more general than
  1392 that of Haskell98, although Isabelle does not demand an exact
  1393 correspondence to type class and instance declarations.
  1394 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1395 exotic versions of overloading -- at the discretion of the user!
  1396 
  1397 Polymorphic constants are represented via type arguments, i.e. the
  1398 instantiation that matches an instance against the most general
  1399 declaration given in the signature.  For example, with the declaration
  1400 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1401 as c(nat).  Overloading is essentially simultaneous structural
  1402 recursion over such type arguments.  Incomplete specification patterns
  1403 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1404 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1405 Command 'print_theory' outputs the normalized system of recursive
  1406 equations, see section "definitions".
  1407 
  1408 * Configuration options are maintained within the theory or proof
  1409 context (with name and type bool/int/string), providing a very simple
  1410 interface to a poor-man's version of general context data.  Tools may
  1411 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1412 these values using Config.get etc.  Users may change options via an
  1413 associated attribute of the same name.  This form of context
  1414 declaration works particularly well with commands 'declare' or
  1415 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1416 very easy to avoid global references, which would not observe Isar
  1417 toplevel undo/redo and fail to work with multithreading.
  1418 
  1419 Various global ML references of Pure and HOL have been turned into
  1420 configuration options:
  1421 
  1422   Unify.search_bound		unify_search_bound
  1423   Unify.trace_bound		unify_trace_bound
  1424   Unify.trace_simp		unify_trace_simp
  1425   Unify.trace_types		unify_trace_types
  1426   Simplifier.simp_depth_limit	simp_depth_limit
  1427   Blast.depth_limit		blast_depth_limit
  1428   DatatypeProp.dtK		datatype_distinctness_limit
  1429   fast_arith_neq_limit  	fast_arith_neq_limit
  1430   fast_arith_split_limit	fast_arith_split_limit
  1431 
  1432 * Named collections of theorems may be easily installed as context
  1433 data using the functor NamedThmsFun (see also
  1434 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1435 attributes; there is also a toplevel print command.  This facility is
  1436 just a common case of general context data, which is the preferred way
  1437 for anything more complex than just a list of facts in canonical
  1438 order.
  1439 
  1440 * Isar: command 'declaration' augments a local theory by generic
  1441 declaration functions written in ML.  This enables arbitrary content
  1442 being added to the context, depending on a morphism that tells the
  1443 difference of the original declaration context wrt. the application
  1444 context encountered later on.
  1445 
  1446 * Isar: proper interfaces for simplification procedures.  Command
  1447 'simproc_setup' declares named simprocs (with match patterns, and body
  1448 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1449 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1450 
  1451 * Isar: an extra pair of brackets around attribute declarations
  1452 abbreviates a theorem reference involving an internal dummy fact,
  1453 which will be ignored later --- only the effect of the attribute on
  1454 the background context will persist.  This form of in-place
  1455 declarations is particularly useful with commands like 'declare' and
  1456 'using', for example ``have A using [[simproc a]] by simp''.
  1457 
  1458 * Isar: method "assumption" (and implicit closing of subproofs) now
  1459 takes simple non-atomic goal assumptions into account: after applying
  1460 an assumption as a rule the resulting subgoals are solved by atomic
  1461 assumption steps.  This is particularly useful to finish 'obtain'
  1462 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1463 without referring to the original premise "!!x. P x ==> thesis" in the
  1464 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1465 more permissive.
  1466 
  1467 * Isar: implicit use of prems from the Isar proof context is
  1468 considered a legacy feature.  Common applications like ``have A .''
  1469 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1470 referencing facts explicitly here improves readability and
  1471 maintainability of proof texts.
  1472 
  1473 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1474 the obtained context from the course of reasoning!  For example:
  1475 
  1476   assume "EX x y. A x & B y"   -- "any previous fact"
  1477   then guess x and y by clarify
  1478 
  1479 This technique is potentially adventurous, depending on the facts and
  1480 proof tools being involved here.
  1481 
  1482 * Isar: known facts from the proof context may be specified as literal
  1483 propositions, using ASCII back-quote syntax.  This works wherever
  1484 named facts used to be allowed so far, in proof commands, proof
  1485 methods, attributes etc.  Literal facts are retrieved from the context
  1486 according to unification of type and term parameters.  For example,
  1487 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1488 theorems in the current context, then these are valid literal facts:
  1489 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1490 
  1491 There is also a proof method "fact" which does the same composition
  1492 for explicit goal states, e.g. the following proof texts coincide with
  1493 certain special cases of literal facts:
  1494 
  1495   have "A" by fact                 ==  note `A`
  1496   have "A ==> B" by fact           ==  note `A ==> B`
  1497   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1498   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1499 
  1500 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1501 outer syntax.  Thus symbolic identifiers may be used without
  1502 additional white space in declarations like this: ``assume *: A''.
  1503 
  1504 * Isar: 'print_facts' prints all local facts of the current context,
  1505 both named and unnamed ones.
  1506 
  1507 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1508 
  1509   def x == "t" and y == "u"
  1510 
  1511 * Isar: added command 'unfolding', which is structurally similar to
  1512 'using', but affects both the goal state and facts by unfolding given
  1513 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1514 'unfolded' attribute may be replaced by first-class proof text.
  1515 
  1516 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1517 and command 'unfolding' now all support object-level equalities
  1518 (potentially conditional).  The underlying notion of rewrite rule is
  1519 analogous to the 'rule_format' attribute, but *not* that of the
  1520 Simplifier (which is usually more generous).
  1521 
  1522 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1523 premises of a theorem by n. Useful in conjunction with drule.
  1524 
  1525 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1526 method expression within a sandbox consisting of the first N
  1527 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1528 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1529 simplifies all new goals that emerge from applying rule foo to the
  1530 originally first one.
  1531 
  1532 * Isar: schematic goals are no longer restricted to higher-order
  1533 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1534 expected.
  1535 
  1536 * Isar: the conclusion of a long theorem statement is now either
  1537 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1538 (essentially a disjunction of cases with local parameters and
  1539 assumptions).  The latter allows to express general elimination rules
  1540 adequately; in this notation common elimination rules look like this:
  1541 
  1542   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1543     assumes "EX x. P x"
  1544     obtains x where "P x"
  1545 
  1546   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1547     assumes "A & B"
  1548     obtains A and B
  1549 
  1550   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1551     assumes "A | B"
  1552     obtains
  1553       A
  1554     | B
  1555 
  1556 The subsequent classical rules even refer to the formal "thesis"
  1557 explicitly:
  1558 
  1559   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1560     obtains "~ thesis"
  1561 
  1562   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1563     obtains "thesis ==> something"
  1564 
  1565 The actual proof of an 'obtains' statement is analogous to that of the
  1566 Isar proof element 'obtain', only that there may be several cases.
  1567 Optional case names may be specified in parentheses; these will be
  1568 available both in the present proof and as annotations in the
  1569 resulting rule, for later use with the 'cases' method (cf. attribute
  1570 case_names).
  1571 
  1572 * Isar: the assumptions of a long theorem statement are available as
  1573 "assms" fact in the proof context.  This is more appropriate than the
  1574 (historical) "prems", which refers to all assumptions of the current
  1575 context, including those from the target locale, proof body etc.
  1576 
  1577 * Isar: 'print_statement' prints theorems from the current theory or
  1578 proof context in long statement form, according to the syntax of a
  1579 top-level lemma.
  1580 
  1581 * Isar: 'obtain' takes an optional case name for the local context
  1582 introduction rule (default "that").
  1583 
  1584 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1585 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1586 to occur.
  1587 
  1588 * Pure: syntax "CONST name" produces a fully internalized constant
  1589 according to the current context.  This is particularly useful for
  1590 syntax translations that should refer to internal constant
  1591 representations independently of name spaces.
  1592 
  1593 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1594 instead of "FOO ". This allows multiple binder declarations to coexist
  1595 in the same context.  INCOMPATIBILITY.
  1596 
  1597 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1598 primitive that also works in a locale context (both for constants and
  1599 fixed variables). Type declaration and internal syntactic representation
  1600 of given constants retrieved from the context. Likewise, the
  1601 'no_notation' command allows to remove given syntax annotations from the
  1602 current context.
  1603 
  1604 * Isar/locales: new derived specification elements 'axiomatization',
  1605 'definition', 'abbreviation', which support type-inference, admit
  1606 object-level specifications (equality, equivalence).  See also the
  1607 isar-ref manual.  Examples:
  1608 
  1609   axiomatization
  1610     eq  (infix "===" 50) where
  1611     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1612 
  1613   definition "f x y = x + y + 1"
  1614   definition g where "g x = f x x"
  1615 
  1616   abbreviation
  1617     neq  (infix "=!=" 50) where
  1618     "x =!= y == ~ (x === y)"
  1619 
  1620 These specifications may be also used in a locale context.  Then the
  1621 constants being introduced depend on certain fixed parameters, and the
  1622 constant name is qualified by the locale base name.  An internal
  1623 abbreviation takes care for convenient input and output, making the
  1624 parameters implicit and using the original short name.  See also
  1625 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1626 entities from a monomorphic theory.
  1627 
  1628 Presently, abbreviations are only available 'in' a target locale, but
  1629 not inherited by general import expressions.  Also note that
  1630 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1631 'translations' in common applications.  The "no_abbrevs" print mode
  1632 prevents folding of abbreviations in term output.
  1633 
  1634 Concrete syntax is attached to specified constants in internal form,
  1635 independently of name spaces.  The parse tree representation is
  1636 slightly different -- use 'notation' instead of raw 'syntax', and
  1637 'translations' with explicit "CONST" markup to accommodate this.
  1638 
  1639 * Pure/Isar: unified syntax for new-style specification mechanisms
  1640 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1641 full type inference and dummy patterns ("_").  For example:
  1642 
  1643   definition "K x _ = x"
  1644 
  1645   inductive conj for A B
  1646   where "A ==> B ==> conj A B"
  1647 
  1648 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1649 the current context.  Print mode "no_abbrevs" prevents inversion of
  1650 abbreviations on output.
  1651 
  1652 * Isar/locales: improved parameter handling: use of locales "var" and
  1653 "struct" no longer necessary; - parameter renamings are no longer
  1654 required to be injective.  For example, this allows to define
  1655 endomorphisms as locale endom = homom mult mult h.
  1656 
  1657 * Isar/locales: changed the way locales with predicates are defined.
  1658 Instead of accumulating the specification, the imported expression is
  1659 now an interpretation.  INCOMPATIBILITY: different normal form of
  1660 locale expressions.  In particular, in interpretations of locales with
  1661 predicates, goals repesenting already interpreted fragments are not
  1662 removed automatically.  Use methods `intro_locales' and
  1663 `unfold_locales'; see below.
  1664 
  1665 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1666 provide backward reasoning on locales predicates.  The methods are
  1667 aware of interpretations and discharge corresponding goals.
  1668 `intro_locales' is less aggressive then `unfold_locales' and does not
  1669 unfold predicates to assumptions.
  1670 
  1671 * Isar/locales: the order in which locale fragments are accumulated
  1672 has changed.  This enables to override declarations from fragments due
  1673 to interpretations -- for example, unwanted simp rules.
  1674 
  1675 * Isar/locales: interpretation in theories and proof contexts has been
  1676 extended.  One may now specify (and prove) equations, which are
  1677 unfolded in interpreted theorems.  This is useful for replacing
  1678 defined concepts (constants depending on locale parameters) by
  1679 concepts already existing in the target context.  Example:
  1680 
  1681   interpretation partial_order ["op <= :: [int, int] => bool"]
  1682     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1683 
  1684 Typically, the constant `partial_order.less' is created by a
  1685 definition specification element in the context of locale
  1686 partial_order.
  1687 
  1688 * Method "induct": improved internal context management to support
  1689 local fixes and defines on-the-fly. Thus explicit meta-level
  1690 connectives !!  and ==> are rarely required anymore in inductive goals
  1691 (using object-logic connectives for this purpose has been long
  1692 obsolete anyway). Common proof patterns are explained in
  1693 src/HOL/Induct/Common_Patterns.thy, see also
  1694 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1695 examples.
  1696 
  1697 * Method "induct": improved handling of simultaneous goals. Instead of
  1698 introducing object-level conjunction, the statement is now split into
  1699 several conclusions, while the corresponding symbolic cases are nested
  1700 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1701 see src/HOL/Induct/Common_Patterns.thy, for example.
  1702 
  1703 * Method "induct": mutual induction rules are now specified as a list
  1704 of rule sharing the same induction cases. HOL packages usually provide
  1705 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1706 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1707 mutual induction rules differently, i.e. like this:
  1708 
  1709   (induct rule: foo_bar.inducts)
  1710   (induct set: foo bar)
  1711   (induct pred: foo bar)
  1712   (induct type: foo bar)
  1713 
  1714 The ML function ProjectRule.projections turns old-style rules into the
  1715 new format.
  1716 
  1717 * Method "coinduct": dual of induction, see
  1718 src/HOL/Library/Coinductive_List.thy for various examples.
  1719 
  1720 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1721 considered a legacy feature.
  1722 
  1723 * Attribute "symmetric" produces result with standardized schematic
  1724 variables (index 0).  Potential INCOMPATIBILITY.
  1725 
  1726 * Simplifier: by default the simplifier trace only shows top level
  1727 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1728 default. Thus there is less danger of being flooded by the trace. The
  1729 trace indicates where parts have been suppressed.
  1730   
  1731 * Provers/classical: removed obsolete classical version of elim_format
  1732 attribute; classical elim/dest rules are now treated uniformly when
  1733 manipulating the claset.
  1734 
  1735 * Provers/classical: stricter checks to ensure that supplied intro,
  1736 dest and elim rules are well-formed; dest and elim rules must have at
  1737 least one premise.
  1738 
  1739 * Provers/classical: attributes dest/elim/intro take an optional
  1740 weight argument for the rule (just as the Pure versions).  Weights are
  1741 ignored by automated tools, but determine the search order of single
  1742 rule steps.
  1743 
  1744 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1745 where the body does not mention the bound variable.  Note that dummy
  1746 patterns implicitly depend on their context of bounds, which makes
  1747 "{_. _}" match any set comprehension as expected.  Potential
  1748 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1749 constant "_idtdummy" in the binding position.
  1750 
  1751 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1752 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1753 for example "A -> B" => "Pi A (%_. B)".
  1754 
  1755 * Pure: 'class_deps' command visualizes the subclass relation, using
  1756 the graph browser tool.
  1757 
  1758 * Pure: 'print_theory' now suppresses certain internal declarations by
  1759 default; use '!' option for full details.
  1760 
  1761 
  1762 *** HOL ***
  1763 
  1764 * Method "metis" proves goals by applying the Metis general-purpose
  1765 resolution prover (see also http://gilith.com/software/metis/).
  1766 Examples are in the directory MetisExamples.  WARNING: the
  1767 Isabelle/HOL-Metis integration does not yet work properly with
  1768 multi-threading.
  1769   
  1770 * Command 'sledgehammer' invokes external automatic theorem provers as
  1771 background processes.  It generates calls to the "metis" method if
  1772 successful. These can be pasted into the proof.  Users do not have to
  1773 wait for the automatic provers to return.  WARNING: does not really
  1774 work with multi-threading.
  1775 
  1776 * New "auto_quickcheck" feature tests outermost goal statements for
  1777 potential counter-examples.  Controlled by ML references
  1778 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1779 5000 milliseconds).  Fails silently if statements is outside of
  1780 executable fragment, or any other codgenerator problem occurs.
  1781 
  1782 * New constant "undefined" with axiom "undefined x = undefined".
  1783 
  1784 * Added class "HOL.eq", allowing for code generation with polymorphic
  1785 equality.
  1786 
  1787 * Some renaming of class constants due to canonical name prefixing in
  1788 the new 'class' package:
  1789 
  1790     HOL.abs ~> HOL.abs_class.abs
  1791     HOL.divide ~> HOL.divide_class.divide
  1792     0 ~> HOL.zero_class.zero
  1793     1 ~> HOL.one_class.one
  1794     op + ~> HOL.plus_class.plus
  1795     op - ~> HOL.minus_class.minus
  1796     uminus ~> HOL.minus_class.uminus
  1797     op * ~> HOL.times_class.times
  1798     op < ~> HOL.ord_class.less
  1799     op <= > HOL.ord_class.less_eq
  1800     Nat.power ~> Power.power_class.power
  1801     Nat.size ~> Nat.size_class.size
  1802     Numeral.number_of ~> Numeral.number_class.number_of
  1803     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1804     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1805     Orderings.min ~> Orderings.ord_class.min
  1806     Orderings.max ~> Orderings.ord_class.max
  1807     Divides.op div ~> Divides.div_class.div
  1808     Divides.op mod ~> Divides.div_class.mod
  1809     Divides.op dvd ~> Divides.div_class.dvd
  1810 
  1811 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1812 
  1813 a) User-defined constants using any of the names "plus", "minus",
  1814 "times", "less" or "less_eq". The standard syntax translations for
  1815 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1816 names.
  1817 
  1818 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1819 INCOMPATIBILITY: use more specific names.
  1820 
  1821 c) Permutative equations (e.g. "a + b = b + a")
  1822 Since the change of names also changes the order of terms, permutative
  1823 rewrite rules may get applied in a different order. Experience shows
  1824 that this is rarely the case (only two adaptions in the whole Isabelle
  1825 distribution).  INCOMPATIBILITY: rewrite proofs
  1826 
  1827 d) ML code directly refering to constant names
  1828 This in general only affects hand-written proof tactics, simprocs and
  1829 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1830 Consider using @{const_name} antiquotation.
  1831 
  1832 * New class "default" with associated constant "default".
  1833 
  1834 * Function "sgn" is now overloaded and available on int, real, complex
  1835 (and other numeric types), using class "sgn".  Two possible defs of
  1836 sgn are given as equational assumptions in the classes sgn_if and
  1837 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1838 INCOMPATIBILITY.
  1839 
  1840 * Locale "partial_order" now unified with class "order" (cf. theory
  1841 Orderings), added parameter "less".  INCOMPATIBILITY.
  1842 
  1843 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1844 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1845 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1846 
  1847 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1848 changed order of proof goals in instance proofs.
  1849 
  1850 * The transitivity reasoner for partial and linear orders is set up
  1851 for classes "order" and "linorder".  Instances of the reasoner are available
  1852 in all contexts importing or interpreting the corresponding locales.
  1853 Method "order" invokes the reasoner separately; the reasoner
  1854 is also integrated with the Simplifier as a solver.  Diagnostic
  1855 command 'print_orders' shows the available instances of the reasoner
  1856 in the current context.
  1857 
  1858 * Localized monotonicity predicate in theory "Orderings"; integrated
  1859 lemmas max_of_mono and min_of_mono with this predicate.
  1860 INCOMPATIBILITY.
  1861 
  1862 * Formulation of theorem "dense" changed slightly due to integration
  1863 with new class dense_linear_order.
  1864 
  1865 * Uniform lattice theory development in HOL.
  1866 
  1867     constants "meet" and "join" now named "inf" and "sup"
  1868     constant "Meet" now named "Inf"
  1869 
  1870     classes "meet_semilorder" and "join_semilorder" now named
  1871       "lower_semilattice" and "upper_semilattice"
  1872     class "lorder" now named "lattice"
  1873     class "comp_lat" now named "complete_lattice"
  1874 
  1875     Instantiation of lattice classes allows explicit definitions
  1876     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1877 
  1878   INCOMPATIBILITY.  Theorem renames:
  1879 
  1880     meet_left_le            ~> inf_le1
  1881     meet_right_le           ~> inf_le2
  1882     join_left_le            ~> sup_ge1
  1883     join_right_le           ~> sup_ge2
  1884     meet_join_le            ~> inf_sup_ord
  1885     le_meetI                ~> le_infI
  1886     join_leI                ~> le_supI
  1887     le_meet                 ~> le_inf_iff
  1888     le_join                 ~> ge_sup_conv
  1889     meet_idempotent         ~> inf_idem
  1890     join_idempotent         ~> sup_idem
  1891     meet_comm               ~> inf_commute
  1892     join_comm               ~> sup_commute
  1893     meet_leI1               ~> le_infI1
  1894     meet_leI2               ~> le_infI2
  1895     le_joinI1               ~> le_supI1
  1896     le_joinI2               ~> le_supI2
  1897     meet_assoc              ~> inf_assoc
  1898     join_assoc              ~> sup_assoc
  1899     meet_left_comm          ~> inf_left_commute
  1900     meet_left_idempotent    ~> inf_left_idem
  1901     join_left_comm          ~> sup_left_commute
  1902     join_left_idempotent    ~> sup_left_idem
  1903     meet_aci                ~> inf_aci
  1904     join_aci                ~> sup_aci
  1905     le_def_meet             ~> le_iff_inf
  1906     le_def_join             ~> le_iff_sup
  1907     join_absorp2            ~> sup_absorb2
  1908     join_absorp1            ~> sup_absorb1
  1909     meet_absorp1            ~> inf_absorb1
  1910     meet_absorp2            ~> inf_absorb2
  1911     meet_join_absorp        ~> inf_sup_absorb
  1912     join_meet_absorp        ~> sup_inf_absorb
  1913     distrib_join_le         ~> distrib_sup_le
  1914     distrib_meet_le         ~> distrib_inf_le
  1915 
  1916     add_meet_distrib_left   ~> add_inf_distrib_left
  1917     add_join_distrib_left   ~> add_sup_distrib_left
  1918     is_join_neg_meet        ~> is_join_neg_inf
  1919     is_meet_neg_join        ~> is_meet_neg_sup
  1920     add_meet_distrib_right  ~> add_inf_distrib_right
  1921     add_join_distrib_right  ~> add_sup_distrib_right
  1922     add_meet_join_distribs  ~> add_sup_inf_distribs
  1923     join_eq_neg_meet        ~> sup_eq_neg_inf
  1924     meet_eq_neg_join        ~> inf_eq_neg_sup
  1925     add_eq_meet_join        ~> add_eq_inf_sup
  1926     meet_0_imp_0            ~> inf_0_imp_0
  1927     join_0_imp_0            ~> sup_0_imp_0
  1928     meet_0_eq_0             ~> inf_0_eq_0
  1929     join_0_eq_0             ~> sup_0_eq_0
  1930     neg_meet_eq_join        ~> neg_inf_eq_sup
  1931     neg_join_eq_meet        ~> neg_sup_eq_inf
  1932     join_eq_if              ~> sup_eq_if
  1933 
  1934     mono_meet               ~> mono_inf
  1935     mono_join               ~> mono_sup
  1936     meet_bool_eq            ~> inf_bool_eq
  1937     join_bool_eq            ~> sup_bool_eq
  1938     meet_fun_eq             ~> inf_fun_eq
  1939     join_fun_eq             ~> sup_fun_eq
  1940     meet_set_eq             ~> inf_set_eq
  1941     join_set_eq             ~> sup_set_eq
  1942     meet1_iff               ~> inf1_iff
  1943     meet2_iff               ~> inf2_iff
  1944     meet1I                  ~> inf1I
  1945     meet2I                  ~> inf2I
  1946     meet1D1                 ~> inf1D1
  1947     meet2D1                 ~> inf2D1
  1948     meet1D2                 ~> inf1D2
  1949     meet2D2                 ~> inf2D2
  1950     meet1E                  ~> inf1E
  1951     meet2E                  ~> inf2E
  1952     join1_iff               ~> sup1_iff
  1953     join2_iff               ~> sup2_iff
  1954     join1I1                 ~> sup1I1
  1955     join2I1                 ~> sup2I1
  1956     join1I1                 ~> sup1I1
  1957     join2I2                 ~> sup1I2
  1958     join1CI                 ~> sup1CI
  1959     join2CI                 ~> sup2CI
  1960     join1E                  ~> sup1E
  1961     join2E                  ~> sup2E
  1962 
  1963     is_meet_Meet            ~> is_meet_Inf
  1964     Meet_bool_def           ~> Inf_bool_def
  1965     Meet_fun_def            ~> Inf_fun_def
  1966     Meet_greatest           ~> Inf_greatest
  1967     Meet_lower              ~> Inf_lower
  1968     Meet_set_def            ~> Inf_set_def
  1969 
  1970     Sup_def                 ~> Sup_Inf
  1971     Sup_bool_eq             ~> Sup_bool_def
  1972     Sup_fun_eq              ~> Sup_fun_def
  1973     Sup_set_eq              ~> Sup_set_def
  1974 
  1975     listsp_meetI            ~> listsp_infI
  1976     listsp_meet_eq          ~> listsp_inf_eq
  1977 
  1978     meet_min                ~> inf_min
  1979     join_max                ~> sup_max
  1980 
  1981 * Added syntactic class "size"; overloaded constant "size" now has
  1982 type "'a::size ==> bool"
  1983 
  1984 * Internal reorganisation of `size' of datatypes: size theorems
  1985 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1986 simplification rules by default!); theorems "prod.size" now named
  1987 "*.size".
  1988 
  1989 * Class "div" now inherits from class "times" rather than "type".
  1990 INCOMPATIBILITY.
  1991 
  1992 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1993 Linorder etc.  have disappeared; operations defined in terms of
  1994 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1995 
  1996 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1997 
  1998 * HOL-Word: New extensive library and type for generic, fixed size
  1999 machine words, with arithemtic, bit-wise, shifting and rotating
  2000 operations, reflection into int, nat, and bool lists, automation for
  2001 linear arithmetic (by automatic reflection into nat or int), including
  2002 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2003 arithmetic type classes, supporting automatic simplification of
  2004 numerals on all operations.
  2005 
  2006 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2007 
  2008 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2009 
  2010 * Code generator library theories:
  2011   - Code_Integer represents HOL integers by big integer literals in target
  2012     languages.
  2013   - Code_Char represents HOL characters by character literals in target
  2014     languages.
  2015   - Code_Char_chr like Code_Char, but also offers treatment of character
  2016     codes; includes Code_Integer.
  2017   - Executable_Set allows to generate code for finite sets using lists.
  2018   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2019     denominator).
  2020   - Executable_Real implements a subset of real numbers, namly those
  2021     representable by rational numbers.
  2022   - Efficient_Nat implements natural numbers by integers, which in general will
  2023     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2024     includes Code_Integer.
  2025   - Code_Index provides an additional datatype index which is mapped to
  2026     target-language built-in integers.
  2027   - Code_Message provides an additional datatype message_string which is isomorphic to
  2028     strings; messages are mapped to target-language strings.
  2029 
  2030 * New package for inductive predicates
  2031 
  2032   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2033 
  2034     inductive
  2035       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2036       for z_1 :: U_1 and ... and z_n :: U_m
  2037     where
  2038       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2039     | ...
  2040 
  2041   with full support for type-inference, rather than
  2042 
  2043     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2044 
  2045     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2046     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2047 
  2048     inductive "s z_1 ... z_m"
  2049     intros
  2050       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2051       ...
  2052 
  2053   For backward compatibility, there is a wrapper allowing inductive
  2054   sets to be defined with the new package via
  2055 
  2056     inductive_set
  2057       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2058       for z_1 :: U_1 and ... and z_n :: U_m
  2059     where
  2060       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2061     | ...
  2062 
  2063   or
  2064 
  2065     inductive_set
  2066       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2067       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2068       for z_1 :: U_1 and ... and z_n :: U_m
  2069     where
  2070       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2071     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2072     | ...
  2073 
  2074   if the additional syntax "p ..." is required.
  2075 
  2076   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2077   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2078 
  2079   INCOMPATIBILITIES:
  2080 
  2081   - Since declaration and definition of inductive sets or predicates
  2082     is no longer separated, abbreviations involving the newly
  2083     introduced sets or predicates must be specified together with the
  2084     introduction rules after the 'where' keyword (see above), rather
  2085     than before the actual inductive definition.
  2086 
  2087   - The variables in induction and elimination rules are now
  2088     quantified in the order of their occurrence in the introduction
  2089     rules, rather than in alphabetical order. Since this may break
  2090     some proofs, these proofs either have to be repaired, e.g. by
  2091     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2092     statements of the form
  2093 
  2094       case (rule_i a_i_1 ... a_i_{k_i})
  2095 
  2096     or the old order of quantification has to be restored by explicitly adding
  2097     meta-level quantifiers in the introduction rules, i.e.
  2098 
  2099       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2100 
  2101   - The format of the elimination rules is now
  2102 
  2103       p z_1 ... z_m x_1 ... x_n ==>
  2104         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2105         ==> ... ==> P
  2106 
  2107     for predicates and
  2108 
  2109       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2110         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2111         ==> ... ==> P
  2112 
  2113     for sets rather than
  2114 
  2115       x : s z_1 ... z_m ==>
  2116         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2117         ==> ... ==> P
  2118 
  2119     This may require terms in goals to be expanded to n-tuples
  2120     (e.g. using case_tac or simplification with the split_paired_all
  2121     rule) before the above elimination rule is applicable.
  2122 
  2123   - The elimination or case analysis rules for (mutually) inductive
  2124     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2125     list of rules "p_1_..._p_k.elims" is no longer available.
  2126 
  2127 * New package "function"/"fun" for general recursive functions,
  2128 supporting mutual and nested recursion, definitions in local contexts,
  2129 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2130 for small examples, and the separate tutorial on the function
  2131 package. The old recdef "package" is still available as before, but
  2132 users are encouraged to use the new package.
  2133 
  2134 * Method "lexicographic_order" automatically synthesizes termination
  2135 relations as lexicographic combinations of size measures. 
  2136 
  2137 * Case-expressions allow arbitrary constructor-patterns (including
  2138 "_") and take their order into account, like in functional
  2139 programming.  Internally, this is translated into nested
  2140 case-expressions; missing cases are added and mapped to the predefined
  2141 constant "undefined". In complicated cases printing may no longer show
  2142 the original input but the internal form. Lambda-abstractions allow
  2143 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2144 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2145 variable.
  2146 
  2147 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2148 is an abbreviation for "of_nat :: nat => int". The simplification
  2149 rules for "of_nat" have been changed to work like "int" did
  2150 previously.  Potential INCOMPATIBILITY:
  2151   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2152   - of_nat_diff and of_nat_mult are no longer default simp rules
  2153 
  2154 * Method "algebra" solves polynomial equations over (semi)rings using
  2155 Groebner bases. The (semi)ring structure is defined by locales and the
  2156 tool setup depends on that generic context. Installing the method for
  2157 a specific type involves instantiating the locale and possibly adding
  2158 declarations for computation on the coefficients.  The method is
  2159 already instantiated for natural numbers and for the axiomatic class
  2160 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2161 CALCULEMUS 2007 for the general principles underlying this
  2162 architecture of context-aware proof-tools.
  2163 
  2164 * Method "ferrack" implements quantifier elimination over
  2165 special-purpose dense linear orders using locales (analogous to
  2166 "algebra"). The method is already installed for class
  2167 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2168 rat, etc.
  2169 
  2170 * Former constant "List.op @" now named "List.append".  Use ML
  2171 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2172 circumvent possible incompatibilities when working on ML level.
  2173 
  2174 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2175 
  2176 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2177 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2178 
  2179 * New syntax for Haskell-like list comprehension (input only), eg.
  2180 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2181 
  2182 * The special syntax for function "filter" has changed from [x :
  2183 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2184 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2185 
  2186 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2187 defined on nat only, as an abbreviation for [a..<Suc b]
  2188 INCOMPATIBILITY.
  2189 
  2190 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2191 
  2192 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2193 
  2194 * New lemma collection field_simps (an extension of ring_simps) for
  2195 manipulating (in)equations involving division. Multiplies with all
  2196 denominators that can be proved to be non-zero (in equations) or
  2197 positive/negative (in inequations).
  2198 
  2199 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2200 have been improved and renamed to ring_simps, group_simps and
  2201 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2202 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2203 
  2204 * Theory Library/Commutative_Ring: switched from recdef to function
  2205 package; constants add, mul, pow now curried.  Infix syntax for
  2206 algebraic operations.
  2207 
  2208 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2209 INCOMPATIBILITY.
  2210 
  2211 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2212 INCOMPATIBILITY.
  2213 
  2214 * HOL/records: generalised field-update to take a function on the
  2215 field rather than the new value: r(|A := x|) is translated to A_update
  2216 (K x) r The K-combinator that is internally used is called K_record.
  2217 INCOMPATIBILITY: Usage of the plain update functions has to be
  2218 adapted.
  2219  
  2220 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2221 * x = 0, which are required for a semiring.  Richer structures do not
  2222 inherit from semiring_0 anymore, because this property is a theorem
  2223 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2224 there is more to prove, but this is mostly trivial.
  2225 
  2226 * Class "recpower" is generalized to arbitrary monoids, not just
  2227 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2228 commutativity or semiring properties additionally.
  2229 
  2230 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2231 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2232 better use 'abbreviation'.
  2233 
  2234 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2235 
  2236 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2237 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2238 significant changes for setting up numeral syntax for types:
  2239   - New constants Numeral.pred and Numeral.succ instead
  2240       of former Numeral.bin_pred and Numeral.bin_succ.
  2241   - Use integer operations instead of bin_add, bin_mult and so on.
  2242   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2243   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2244 
  2245 See src/HOL/Integ/IntArith.thy for an example setup.
  2246 
  2247 * Command 'normal_form' computes the normal form of a term that may
  2248 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2249 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2250 heavy-duty computations because the functions are compiled to ML
  2251 first.  Correspondingly, a method "normalization" is provided.  See
  2252 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2253 
  2254 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2255 25 like -->); output depends on the "iff" print_mode, the default is
  2256 "A = B" (with priority 50).
  2257 
  2258 * Relations less (<) and less_eq (<=) are also available on type bool.
  2259 Modified syntax to disallow nesting without explicit parentheses,
  2260 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2261 INCOMPATIBILITY.
  2262 
  2263 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2264 
  2265 * Relation composition operator "op O" now has precedence 75 and binds
  2266 stronger than union and intersection. INCOMPATIBILITY.
  2267 
  2268 * The old set interval syntax "{m..n(}" (and relatives) has been
  2269 removed.  Use "{m..<n}" (and relatives) instead.
  2270 
  2271 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2272 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2273 ``declare [[simproc del: neq]]''.
  2274 
  2275 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2276 True/False.
  2277 
  2278 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2279 
  2280 * Theorem setsum_mult renamed to setsum_right_distrib.
  2281 
  2282 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2283 ``rule'' method.
  2284 
  2285 * Reimplemented methods "sat" and "satx", with several improvements:
  2286 goals no longer need to be stated as "<prems> ==> False", equivalences
  2287 (i.e. "=" on type bool) are handled, variable names of the form
  2288 "lit_<n>" are no longer reserved, significant speedup.
  2289 
  2290 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2291 zChaff is still supported as well.
  2292 
  2293 * 'inductive' and 'datatype': provide projections of mutual rules,
  2294 bundled as foo_bar.inducts;
  2295 
  2296 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2297 Library.
  2298 
  2299 * Library: moved theory Accessible_Part to main HOL.
  2300 
  2301 * Library: added theory Coinductive_List of potentially infinite lists
  2302 as greatest fixed-point.
  2303 
  2304 * Library: added theory AssocList which implements (finite) maps as
  2305 association lists.
  2306 
  2307 * Method "evaluation" solves goals (i.e. a boolean expression)
  2308 efficiently by compiling it to ML.  The goal is "proved" (via an
  2309 oracle) if it evaluates to True.
  2310 
  2311 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2312 also when invoked by the simplifier.  This results in the Simplifier
  2313 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2314 Configuration option fast_arith_split_limit=0 recovers the old
  2315 behavior.
  2316 
  2317 * Support for hex (0x20) and binary (0b1001) numerals.
  2318 
  2319 * New method: reify eqs (t), where eqs are equations for an
  2320 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2321 parameter, computes a term s::'b and a list xs::'a list and proves the
  2322 theorem I xs s = t. This is also known as reification or quoting. The
  2323 resulting theorem is applied to the subgoal to substitute t with I xs
  2324 s.  If t is omitted, the subgoal itself is reified.
  2325 
  2326 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2327 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2328 where f is supposed to be a computable function (in the sense of code
  2329 generattion). The method uses reify to compute s and xs as above then
  2330 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2331 r and finally gets the theorem t = r, which is again applied to the
  2332 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2333 
  2334 * Reflection: Automatic reification now handels binding, an example is
  2335 available in src/HOL/ex/ReflectionEx.thy
  2336 
  2337 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2338 command 'statespace' that is similar to 'record', but introduces an
  2339 abstract specification based on the locale infrastructure instead of
  2340 HOL types.  This leads to extra flexibility in composing state spaces,
  2341 in particular multiple inheritance and renaming of components.
  2342 
  2343 
  2344 *** HOL-Complex ***
  2345 
  2346 * Hyperreal: Functions root and sqrt are now defined on negative real
  2347 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2348 Nonnegativity side conditions have been removed from many lemmas, so
  2349 that more subgoals may now be solved by simplification; potential
  2350 INCOMPATIBILITY.
  2351 
  2352 * Real: new type classes formalize real normed vector spaces and
  2353 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2354 and norm :: 'a => real.
  2355 
  2356 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2357 reals into other types. The overloaded constant Reals :: 'a set is now
  2358 defined as range of_real; potential INCOMPATIBILITY.
  2359 
  2360 * Real: proper support for ML code generation, including 'quickcheck'.
  2361 Reals are implemented as arbitrary precision rationals.
  2362 
  2363 * Hyperreal: Several constants that previously worked only for the
  2364 reals have been generalized, so they now work over arbitrary vector
  2365 spaces. Type annotations may need to be added in some cases; potential
  2366 INCOMPATIBILITY.
  2367 
  2368   Infinitesimal  :: ('a::real_normed_vector) star set
  2369   HFinite        :: ('a::real_normed_vector) star set
  2370   HInfinite      :: ('a::real_normed_vector) star set
  2371   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2372   monad          :: ('a::real_normed_vector) star => 'a star set
  2373   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2374   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2375   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2376   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2377   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2378   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2379   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2380   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2381   sgn            :: 'a::real_normed_vector => 'a
  2382   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2383 
  2384 * Complex: Some complex-specific constants are now abbreviations for
  2385 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2386 hnorm.  Other constants have been entirely removed in favor of the
  2387 polymorphic versions (INCOMPATIBILITY):
  2388 
  2389   approx        <-- capprox
  2390   HFinite       <-- CFinite
  2391   HInfinite     <-- CInfinite
  2392   Infinitesimal <-- CInfinitesimal
  2393   monad         <-- cmonad
  2394   galaxy        <-- cgalaxy
  2395   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2396   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2397   (ns)deriv     <-- (ns)cderiv
  2398 
  2399 
  2400 *** HOL-Algebra ***
  2401 
  2402 * Formalisation of ideals and the quotient construction over rings.
  2403 
  2404 * Order and lattice theory no longer based on records.
  2405 INCOMPATIBILITY.
  2406 
  2407 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2408 greatest_closed.  INCOMPATIBILITY.
  2409 
  2410 * Method algebra is now set up via an attribute.  For examples see
  2411 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2412 of algebraic structures.
  2413 
  2414 * Renamed theory CRing to Ring.
  2415 
  2416 
  2417 *** HOL-Nominal ***
  2418 
  2419 * Substantial, yet incomplete support for nominal datatypes (binding
  2420 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2421 src/HOL/Nominal/Examples.  Prospective users should consult
  2422 http://isabelle.in.tum.de/nominal/
  2423 
  2424 
  2425 *** ML ***
  2426 
  2427 * ML basics: just one true type int, which coincides with IntInf.int
  2428 (even on SML/NJ).
  2429 
  2430 * ML within Isar: antiquotations allow to embed statically-checked
  2431 formal entities in the source, referring to the context available at
  2432 compile-time.  For example:
  2433 
  2434 ML {* @{sort "{zero,one}"} *}
  2435 ML {* @{typ "'a => 'b"} *}
  2436 ML {* @{term "%x. x"} *}
  2437 ML {* @{prop "x == y"} *}
  2438 ML {* @{ctyp "'a => 'b"} *}
  2439 ML {* @{cterm "%x. x"} *}
  2440 ML {* @{cprop "x == y"} *}
  2441 ML {* @{thm asm_rl} *}
  2442 ML {* @{thms asm_rl} *}
  2443 ML {* @{type_name c} *}
  2444 ML {* @{type_syntax c} *}
  2445 ML {* @{const_name c} *}
  2446 ML {* @{const_syntax c} *}
  2447 ML {* @{context} *}
  2448 ML {* @{theory} *}
  2449 ML {* @{theory Pure} *}
  2450 ML {* @{theory_ref} *}
  2451 ML {* @{theory_ref Pure} *}
  2452 ML {* @{simpset} *}
  2453 ML {* @{claset} *}
  2454 ML {* @{clasimpset} *}
  2455 
  2456 The same works for sources being ``used'' within an Isar context.
  2457 
  2458 * ML in Isar: improved error reporting; extra verbosity with
  2459 ML_Context.trace enabled.
  2460 
  2461 * Pure/General/table.ML: the join operations now works via exceptions
  2462 DUP/SAME instead of type option. This is simpler in simple cases, and
  2463 admits slightly more efficient complex applications.
  2464 
  2465 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2466 use Context.generic instead of just theory.
  2467 
  2468 * Pure: datatype Context.generic joins theory/Proof.context and
  2469 provides some facilities for code that works in either kind of
  2470 context, notably GenericDataFun for uniform theory and proof data.
  2471 
  2472 * Pure: simplified internal attribute type, which is now always
  2473 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2474 local (Proof.context) attributes have been discontinued, while
  2475 minimizing code duplication. Thm.rule_attribute and
  2476 Thm.declaration_attribute build canonical attributes; see also structure
  2477 Context for further operations on Context.generic, notably
  2478 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2479 declarations and definitions.
  2480 
  2481 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2482 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2483 init only required for impure data. INCOMPATIBILITY: empty really need
  2484 to be empty (no dependencies on theory content!)
  2485 
  2486 * Pure/kernel: consts certification ignores sort constraints given in
  2487 signature declarations. (This information is not relevant to the
  2488 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2489 potential INCOMPATIBILITY.
  2490 
  2491 * Pure: axiomatic type classes are now purely definitional, with
  2492 explicit proofs of class axioms and super class relations performed
  2493 internally. See Pure/axclass.ML for the main internal interfaces --
  2494 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2495 AxClass.axiomatize_class/classrel/arity supersede
  2496 Sign.add_classes/classrel/arities.
  2497 
  2498 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2499 global/local versions on theory vs. Proof.context have been
  2500 discontinued; Attrib.syntax and Method.syntax have been adapted
  2501 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2502 attributes, methods, etc.
  2503 
  2504 * Pure: several functions of signature "... -> theory -> theory * ..."
  2505 have been reoriented to "... -> theory -> ... * theory" in order to
  2506 allow natural usage in combination with the ||>, ||>>, |-> and
  2507 fold_map combinators.
  2508 
  2509 * Pure: official theorem names (closed derivations) and additional
  2510 comments (tags) are now strictly separate.  Name hints -- which are
  2511 maintained as tags -- may be attached any time without affecting the
  2512 derivation.
  2513 
  2514 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2515 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2516 achieve the old behaviour.
  2517 
  2518 * Pure: the "Goal" constant is now called "prop", supporting a
  2519 slightly more general idea of ``protecting'' meta-level rule
  2520 statements.
  2521 
  2522 * Pure: Logic.(un)varify only works in a global context, which is now
  2523 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2524 Logic.legacy_(un)varify as temporary workaround.
  2525 
  2526 * Pure: structure Name provides scalable operations for generating
  2527 internal variable names, notably Name.variants etc.  This replaces
  2528 some popular functions from term.ML:
  2529 
  2530   Term.variant		->  Name.variant
  2531   Term.variantlist	->  Name.variant_list
  2532   Term.invent_names	->  Name.invent_list
  2533 
  2534 Note that low-level renaming rarely occurs in new code -- operations
  2535 from structure Variable are used instead (see below).
  2536 
  2537 * Pure: structure Variable provides fundamental operations for proper
  2538 treatment of fixed/schematic variables in a context.  For example,
  2539 Variable.import introduces fixes for schematics of given facts and
  2540 Variable.export reverses the effect (up to renaming) -- this replaces
  2541 various freeze_thaw operations.
  2542 
  2543 * Pure: structure Goal provides simple interfaces for
  2544 init/conclude/finish and tactical prove operations (replacing former
  2545 Tactic.prove).  Goal.prove is the canonical way to prove results
  2546 within a given context; Goal.prove_global is a degraded version for
  2547 theory level goals, including a global Drule.standard.  Note that
  2548 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2549 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2550 in a locale context).
  2551 
  2552 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2553 and type checking (Syntax.check_term etc.), with common combinations
  2554 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2555 which are considered legacy and await removal.
  2556 
  2557 * Pure/Syntax: generic interfaces for type unchecking
  2558 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2559 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2560 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2561 available for convenience, but refer to the very same operations using
  2562 a mere theory instead of a full context.
  2563 
  2564 * Isar: simplified treatment of user-level errors, using exception
  2565 ERROR of string uniformly.  Function error now merely raises ERROR,
  2566 without any side effect on output channels.  The Isar toplevel takes
  2567 care of proper display of ERROR exceptions.  ML code may use plain
  2568 handle/can/try; cat_error may be used to concatenate errors like this:
  2569 
  2570   ... handle ERROR msg => cat_error msg "..."
  2571 
  2572 Toplevel ML code (run directly or through the Isar toplevel) may be
  2573 embedded into the Isar toplevel with exception display/debug like
  2574 this:
  2575 
  2576   Isar.toplevel (fn () => ...)
  2577 
  2578 INCOMPATIBILITY, removed special transform_error facilities, removed
  2579 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2580 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2581 -- use plain ERROR instead.
  2582 
  2583 * Isar: theory setup now has type (theory -> theory), instead of a
  2584 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2585 
  2586 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2587 ProofContext.debug/verbose flags.
  2588 
  2589 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2590 theory before entering a proof state.  Transactions now always see a
  2591 quasi-functional intermediate checkpoint, both in interactive and
  2592 batch mode.
  2593 
  2594 * Isar: simplified interfaces for outer syntax.  Renamed
  2595 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2596 OuterSyntax.add_parsers -- this functionality is now included in
  2597 OuterSyntax.command etc.  INCOMPATIBILITY.
  2598 
  2599 * Simplifier: the simpset of a running simplification process now
  2600 contains a proof context (cf. Simplifier.the_context), which is the
  2601 very context that the initial simpset has been retrieved from (by
  2602 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2603 (solver, looper etc.) may depend on arbitrary proof data.
  2604 
  2605 * Simplifier.inherit_context inherits the proof context (plus the
  2606 local bounds) of the current simplification process; any simproc
  2607 etc. that calls the Simplifier recursively should do this!  Removed
  2608 former Simplifier.inherit_bounds, which is already included here --
  2609 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2610 specify an explicit context using Simplifier.context/theory_context.
  2611 
  2612 * Simplifier/Classical Reasoner: more abstract interfaces
  2613 change_simpset/claset for modifying the simpset/claset reference of a
  2614 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2615 INCOMPATIBILITY.
  2616 
  2617 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2618 "Trueprop" etc.
  2619 
  2620 
  2621 *** System ***
  2622 
  2623 * settings: the default heap location within ISABELLE_HOME_USER now
  2624 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2625 Isabelle installations.
  2626 
  2627 * isabelle-process: option -S (secure mode) disables some critical
  2628 operations, notably runtime compilation and evaluation of ML source
  2629 code.
  2630 
  2631 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2632 
  2633 * Support for parallel execution, using native multicore support of
  2634 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2635 independent theories, according to the given theory header
  2636 specifications. The maximum number of worker threads is specified via
  2637 usedir option -M or the "max-threads" setting in Proof General. A
  2638 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2639 to 6 on a 8-core machine.  User-code needs to observe certain
  2640 guidelines for thread-safe programming, see appendix A in the Isar
  2641 Implementation manual.
  2642 
  2643 
  2644 
  2645 New in Isabelle2005 (October 2005)
  2646 ----------------------------------
  2647 
  2648 *** General ***
  2649 
  2650 * Theory headers: the new header syntax for Isar theories is
  2651 
  2652   theory <name>
  2653   imports <theory1> ... <theoryN>
  2654   uses <file1> ... <fileM>
  2655   begin
  2656 
  2657 where the 'uses' part is optional.  The previous syntax
  2658 
  2659   theory <name> = <theory1> + ... + <theoryN>:
  2660 
  2661 will disappear in the next release.  Use isatool fixheaders to convert
  2662 existing theory files.  Note that there is no change in ancient
  2663 non-Isar theories now, but these will disappear soon.
  2664 
  2665 * Theory loader: parent theories can now also be referred to via
  2666 relative and absolute paths.
  2667 
  2668 * Command 'find_theorems' searches for a list of criteria instead of a
  2669 list of constants. Known criteria are: intro, elim, dest, name:string,
  2670 simp:term, and any term. Criteria can be preceded by '-' to select
  2671 theorems that do not match. Intro, elim, dest select theorems that
  2672 match the current goal, name:s selects theorems whose fully qualified
  2673 name contain s, and simp:term selects all simplification rules whose
  2674 lhs match term.  Any other term is interpreted as pattern and selects
  2675 all theorems matching the pattern. Available in ProofGeneral under
  2676 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2677 
  2678   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2679 
  2680 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2681 matching the current goal as introduction rule and not having "HOL."
  2682 in their name (i.e. not being defined in theory HOL).
  2683 
  2684 * Command 'thms_containing' has been discontinued in favour of
  2685 'find_theorems'; INCOMPATIBILITY.
  2686 
  2687 * Communication with Proof General is now 8bit clean, which means that
  2688 Unicode text in UTF-8 encoding may be used within theory texts (both
  2689 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2690 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2691 
  2692   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2693   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2694 
  2695 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2696 Classical Reasoner.  Typical big applications run around 2 times
  2697 faster.
  2698 
  2699 
  2700 *** Document preparation ***
  2701 
  2702 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2703 of raw sources.  Only those symbols that do not require additional
  2704 LaTeX packages (depending on comments in isabellesym.sty) are
  2705 displayed properly, everything else is left verbatim.  isatool display
  2706 and isatool print are used as front ends (these are subject to the
  2707 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2708 
  2709 * Command tags control specific markup of certain regions of text,
  2710 notably folding and hiding.  Predefined tags include "theory" (for
  2711 theory begin and end), "proof" for proof commands, and "ML" for
  2712 commands involving ML code; the additional tags "visible" and
  2713 "invisible" are unused by default.  Users may give explicit tag
  2714 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2715 interpretation of tags is determined by the LaTeX job during document
  2716 preparation: see option -V of isatool usedir, or options -n and -t of
  2717 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2718 \isadroptag.
  2719 
  2720 Several document versions may be produced at the same time via isatool
  2721 usedir (the generated index.html will link all of them).  Typical
  2722 specifications include ''-V document=theory,proof,ML'' to present
  2723 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2724 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2725 these parts without any formal replacement text.  The Isabelle site
  2726 default settings produce ''document'' and ''outline'' versions as
  2727 specified above.
  2728 
  2729 * Several new antiquotations:
  2730 
  2731   @{term_type term} prints a term with its type annotated;
  2732 
  2733   @{typeof term} prints the type of a term;
  2734 
  2735   @{const const} is the same as @{term const}, but checks that the
  2736   argument is a known logical constant;
  2737 
  2738   @{term_style style term} and @{thm_style style thm} print a term or
  2739   theorem applying a "style" to it
  2740 
  2741   @{ML text}
  2742 
  2743 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2744 definitions, equations, inequations etc., 'concl' printing only the
  2745 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2746 to print the specified premise.  TermStyle.add_style provides an ML
  2747 interface for introducing further styles.  See also the "LaTeX Sugar"
  2748 document practical applications.  The ML antiquotation prints
  2749 type-checked ML expressions verbatim.
  2750 
  2751 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2752 and 'text' support optional locale specification '(in loc)', which
  2753 specifies the default context for interpreting antiquotations.  For
  2754 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2755 
  2756 * Option 'locale=NAME' of antiquotations specifies an alternative
  2757 context interpreting the subsequent argument.  For example: @{thm
  2758 [locale=lattice] inf_assoc}.
  2759 
  2760 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2761 a proof context.
  2762 
  2763 * Proper output of antiquotations for theory commands involving a
  2764 proof context (such as 'locale' or 'theorem (in loc) ...').
  2765 
  2766 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2767 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2768 
  2769 * isatool usedir: new option -C (default true) controls whether option
  2770 -D should include a copy of the original document directory; -C false
  2771 prevents unwanted effects such as copying of administrative CVS data.
  2772 
  2773 
  2774 *** Pure ***
  2775 
  2776 * Considerably improved version of 'constdefs' command.  Now performs
  2777 automatic type-inference of declared constants; additional support for
  2778 local structure declarations (cf. locales and HOL records), see also
  2779 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2780 sequential dependencies of definitions within a single 'constdefs'
  2781 section; moreover, the declared name needs to be an identifier.  If
  2782 all fails, consider to fall back on 'consts' and 'defs' separately.
  2783 
  2784 * Improved indexed syntax and implicit structures.  First of all,
  2785 indexed syntax provides a notational device for subscripted
  2786 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2787 expressions.  Secondly, in a local context with structure
  2788 declarations, number indexes \<^sub>n or the empty index (default
  2789 number 1) refer to a certain fixed variable implicitly; option
  2790 show_structs controls printing of implicit structures.  Typical
  2791 applications of these concepts involve record types and locales.
  2792 
  2793 * New command 'no_syntax' removes grammar declarations (and
  2794 translations) resulting from the given syntax specification, which is
  2795 interpreted in the same manner as for the 'syntax' command.
  2796 
  2797 * 'Advanced' translation functions (parse_translation etc.) may depend
  2798 on the signature of the theory context being presently used for
  2799 parsing/printing, see also isar-ref manual.
  2800 
  2801 * Improved 'oracle' command provides a type-safe interface to turn an
  2802 ML expression of type theory -> T -> term into a primitive rule of
  2803 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2804 is already included here); see also FOL/ex/IffExample.thy;
  2805 INCOMPATIBILITY.
  2806 
  2807 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2808 before); "cI" is no longer bound, use "c.intro" instead.
  2809 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2810 axclasses vs. locales.
  2811 
  2812 * Improved internal renaming of symbolic identifiers -- attach primes
  2813 instead of base 26 numbers.
  2814 
  2815 * New flag show_question_marks controls printing of leading question
  2816 marks in schematic variable names.
  2817 
  2818 * In schematic variable names, *any* symbol following \<^isub> or
  2819 \<^isup> is now treated as part of the base name.  For example, the
  2820 following works without printing of awkward ".0" indexes:
  2821 
  2822   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2823     by simp
  2824 
  2825 * Inner syntax includes (*(*nested*) comments*).
  2826 
  2827 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2828 annotations as "(00...)".
  2829 
  2830 * Clear separation of logical types and nonterminals, where the latter
  2831 may only occur in 'syntax' specifications or type abbreviations.
  2832 Before that distinction was only partially implemented via type class
  2833 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2834 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2835 exotic syntax specifications may require further adaption
  2836 (e.g. Cube/Cube.thy).
  2837 
  2838 * Removed obsolete type class "logic", use the top sort {} instead.
  2839 Note that non-logical types should be declared as 'nonterminals'
  2840 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2841 specifications.
  2842 
  2843 * Attributes 'induct' and 'cases': type or set names may now be
  2844 locally fixed variables as well.
  2845 
  2846 * Simplifier: can now control the depth to which conditional rewriting
  2847 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2848 Limit.
  2849 
  2850 * Simplifier: simplification procedures may now take the current
  2851 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2852 interface), which is very useful for calling the Simplifier
  2853 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2854 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2855 low-level mk_simproc no longer applies Logic.varify internally, to
  2856 allow for use in a context of fixed variables.
  2857 
  2858 * thin_tac now works even if the assumption being deleted contains !!
  2859 or ==>.  More generally, erule now works even if the major premise of
  2860 the elimination rule contains !! or ==>.
  2861 
  2862 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2863 
  2864 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2865 from Pure, which contains all common declarations already.  Both
  2866 theories are defined via plain Isabelle/Isar .thy files.
  2867 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2868 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2869 use isatool fixcpure to adapt your theory and ML sources.
  2870 
  2871 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2872 selections of theorems in named facts via index ranges.
  2873 
  2874 * 'print_theorems': in theory mode, really print the difference
  2875 wrt. the last state (works for interactive theory development only),
  2876 in proof mode print all local facts (cf. 'print_facts');
  2877 
  2878 * 'hide': option '(open)' hides only base names.
  2879 
  2880 * More efficient treatment of intermediate checkpoints in interactive
  2881 theory development.
  2882 
  2883 * Code generator is now invoked via code_module (incremental code
  2884 generation) and code_library (modular code generation, ML structures
  2885 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2886 must be quoted when used as identifiers.
  2887 
  2888 * New 'value' command for reading, evaluating and printing terms using
  2889 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2890 quoted when used as identifier.
  2891 
  2892 
  2893 *** Locales ***
  2894 
  2895 * New commands for the interpretation of locale expressions in
  2896 theories (1), locales (2) and proof contexts (3).  These generate
  2897 proof obligations from the expression specification.  After the
  2898 obligations have been discharged, theorems of the expression are added
  2899 to the theory, target locale or proof context.  The synopsis of the
  2900 commands is a follows:
  2901 
  2902   (1) interpretation expr inst
  2903   (2) interpretation target < expr
  2904   (3) interpret expr inst
  2905 
  2906 Interpretation in theories and proof contexts require a parameter
  2907 instantiation of terms from the current context.  This is applied to
  2908 specifications and theorems of the interpreted expression.
  2909 Interpretation in locales only permits parameter renaming through the
  2910 locale expression.  Interpretation is smart in that interpretations
  2911 that are active already do not occur in proof obligations, neither are
  2912 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2913 inspect active interpretations of a particular locale.  For details,
  2914 see the Isar Reference manual.  Examples can be found in
  2915 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2916 
  2917 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2918 'interpret' instead.
  2919 
  2920 * New context element 'constrains' for adding type constraints to
  2921 parameters.
  2922 
  2923 * Context expressions: renaming of parameters with syntax
  2924 redeclaration.
  2925 
  2926 * Locale declaration: 'includes' disallowed.
  2927 
  2928 * Proper static binding of attribute syntax -- i.e. types / terms /
  2929 facts mentioned as arguments are always those of the locale definition
  2930 context, independently of the context of later invocations.  Moreover,
  2931 locale operations (renaming and type / term instantiation) are applied
  2932 to attribute arguments as expected.
  2933 
  2934 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2935 actual attributes; rare situations may require Attrib.attribute to
  2936 embed those attributes into Attrib.src that lack concrete syntax.
  2937 Attribute implementations need to cooperate properly with the static
  2938 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2939 Attrib.XXX_thm etc. already do the right thing without further
  2940 intervention.  Only unusual applications -- such as "where" or "of"
  2941 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2942 on the context and the facts involved -- may have to assign parsed
  2943 values to argument tokens explicitly.
  2944 
  2945 * Changed parameter management in theorem generation for long goal
  2946 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2947 theorem statement in rare situations.
  2948 
  2949 * Locale inspection command 'print_locale' omits notes elements.  Use
  2950 'print_locale!' to have them included in the output.
  2951 
  2952 
  2953 *** Provers ***
  2954 
  2955 * Provers/hypsubst.ML: improved version of the subst method, for
  2956 single-step rewriting: it now works in bound variable contexts. New is
  2957 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2958 rewrite a different subterm than the original subst method, which is
  2959 still available as 'simplesubst'.
  2960 
  2961 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2962 and quasi orders.
  2963 
  2964 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2965 reflexive-transitive closure of relations.
  2966 
  2967 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2968 limit (previously hard-coded with a value of 20) user-definable.
  2969 
  2970 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2971 is peformed already.  Object-logics merely need to finish their
  2972 initial simpset configuration as before.  INCOMPATIBILITY.
  2973 
  2974 
  2975 *** HOL ***
  2976 
  2977 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2978 
  2979   syntax (epsilon)
  2980     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2981 
  2982 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2983 and x-symbol; use option '-m epsilon' to get it actually printed.
  2984 Moreover, the mathematically important symbolic identifier \<epsilon>
  2985 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2986 
  2987 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2988 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2989 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2990 support corresponding Isar calculations.
  2991 
  2992 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2993 instead of ":".
  2994 
  2995 * theory SetInterval: changed the syntax for open intervals:
  2996 
  2997   Old       New
  2998   {..n(}    {..<n}
  2999   {)n..}    {n<..}
  3000   {m..n(}   {m..<n}
  3001   {)m..n}   {m<..n}
  3002   {)m..n(}  {m<..<n}
  3003 
  3004 The old syntax is still supported but will disappear in the next
  3005 release.  For conversion use the following Emacs search and replace
  3006 patterns (these are not perfect but work quite well):
  3007 
  3008   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3009   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3010 
  3011 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3012 equalities in commutative rings; method 'algebra' provides a generic
  3013 interface.
  3014 
  3015 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3016 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3017 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3018 be a tuple pattern.
  3019 
  3020 Some new syntax forms are available:
  3021 
  3022   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3023   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3024   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3025   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3026 
  3027 The latter form "\<Sum>x < k. e" used to be based on a separate
  3028 function "Summation", which has been discontinued.
  3029 
  3030 * theory Finite_Set: in structured induction proofs, the insert case
  3031 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3032 (insert F x)'.
  3033 
  3034 * The 'refute' command has been extended to support a much larger
  3035 fragment of HOL, including axiomatic type classes, constdefs and
  3036 typedefs, inductive datatypes and recursion.
  3037 
  3038 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3039 Requires zChaff with proof generation to be installed.  See
  3040 HOL/ex/SAT_Examples.thy for examples.
  3041 
  3042 * Datatype induction via method 'induct' now preserves the name of the
  3043 induction variable. For example, when proving P(xs::'a list) by
  3044 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3045 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3046 in unstructured proof scripts.
  3047 
  3048 * Reworked implementation of records.  Improved scalability for
  3049 records with many fields, avoiding performance problems for type
  3050 inference. Records are no longer composed of nested field types, but
  3051 of nested extension types. Therefore the record type only grows linear
  3052 in the number of extensions and not in the number of fields.  The
  3053 top-level (users) view on records is preserved.  Potential
  3054 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3055 old record representation. The type generated for a record is called
  3056 <record_name>_ext_type.
  3057 
  3058 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3059 proofs triggered by a record definition or a simproc (if
  3060 quick_and_dirty is enabled).  Definitions of large records can take
  3061 quite long.
  3062 
  3063 New simproc record_upd_simproc for simplification of multiple record
  3064 updates enabled by default.  Moreover, trivial updates are also
  3065 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3066 occasionally, since simplification is more powerful by default.
  3067 
  3068 * typedef: proper support for polymorphic sets, which contain extra
  3069 type-variables in the term.
  3070 
  3071 * Simplifier: automatically reasons about transitivity chains
  3072 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3073 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3074 old proofs break occasionally as simplification may now solve more
  3075 goals than previously.
  3076 
  3077 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3078 present.  Works for all partial orders (class "order"), in particular
  3079 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3080 just like y <= x.
  3081 
  3082 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3083 bound variable or a constant then the let is unfolded.  Otherwise
  3084 first a is simplified to b, and then f b is simplified to g. If
  3085 possible we abstract b from g arriving at "let x = b in h x",
  3086 otherwise we unfold the let and arrive at g.  The simproc can be
  3087 enabled/disabled by the reference use_let_simproc.  Potential
  3088 INCOMPATIBILITY since simplification is more powerful by default.
  3089 
  3090 * Classical reasoning: the meson method now accepts theorems as arguments.
  3091 
  3092 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3093 jobs to provide advice on the provability of subgoals.
  3094 
  3095 * Theory OrderedGroup and Ring_and_Field: various additions and
  3096 improvements to faciliate calculations involving equalities and
  3097 inequalities.
  3098 
  3099 The following theorems have been eliminated or modified
  3100 (INCOMPATIBILITY):
  3101 
  3102   abs_eq             now named abs_of_nonneg
  3103   abs_of_ge_0        now named abs_of_nonneg
  3104   abs_minus_eq       now named abs_of_nonpos
  3105   imp_abs_id         now named abs_of_nonneg
  3106   imp_abs_neg_id     now named abs_of_nonpos
  3107   mult_pos           now named mult_pos_pos
  3108   mult_pos_le        now named mult_nonneg_nonneg
  3109   mult_pos_neg_le    now named mult_nonneg_nonpos
  3110   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3111   mult_neg           now named mult_neg_neg
  3112   mult_neg_le        now named mult_nonpos_nonpos
  3113 
  3114 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3115      
  3116      zero_le_square
  3117      not_square_less_zero 
  3118 
  3119   The following lemmas have been deleted from Real/RealPow:
  3120   
  3121      realpow_zero_zero
  3122      realpow_two
  3123      realpow_less
  3124      zero_le_power
  3125      realpow_two_le
  3126      abs_realpow_two
  3127      realpow_two_abs     
  3128 
  3129 * Theory Parity: added rules for simplifying exponents.
  3130 
  3131 * Theory List:
  3132 
  3133 The following theorems have been eliminated or modified
  3134 (INCOMPATIBILITY):
  3135 
  3136   list_all_Nil       now named list_all.simps(1)
  3137   list_all_Cons      now named list_all.simps(2)
  3138   list_all_conv      now named list_all_iff
  3139   set_mem_eq         now named mem_iff
  3140 
  3141 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3142 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3143 
  3144 
  3145 *** HOL-Complex ***
  3146 
  3147 * Theory RealDef: better support for embedding natural numbers and
  3148 integers in the reals.
  3149 
  3150 The following theorems have been eliminated or modified
  3151 (INCOMPATIBILITY):
  3152 
  3153   exp_ge_add_one_self  now requires no hypotheses
  3154   real_of_int_add      reversed direction of equality (use [symmetric])
  3155   real_of_int_minus    reversed direction of equality (use [symmetric])
  3156   real_of_int_diff     reversed direction of equality (use [symmetric])
  3157   real_of_int_mult     reversed direction of equality (use [symmetric])
  3158 
  3159 * Theory RComplete: expanded support for floor and ceiling functions.
  3160 
  3161 * Theory Ln is new, with properties of the natural logarithm
  3162 
  3163 * Hyperreal: There is a new type constructor "star" for making
  3164 nonstandard types.  The old type names are now type synonyms:
  3165 
  3166   hypreal = real star
  3167   hypnat = nat star
  3168   hcomplex = complex star
  3169 
  3170 * Hyperreal: Many groups of similarly-defined constants have been
  3171 replaced by polymorphic versions (INCOMPATIBILITY):
  3172 
  3173   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3174 
  3175   starset      <-- starsetNat, starsetC
  3176   *s*          <-- *sNat*, *sc*
  3177   starset_n    <-- starsetNat_n, starsetC_n
  3178   *sn*         <-- *sNatn*, *scn*
  3179   InternalSets <-- InternalNatSets, InternalCSets
  3180 
  3181   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3182   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3183   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3184   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3185   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3186 
  3187 * Hyperreal: Many type-specific theorems have been removed in favor of
  3188 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3189 
  3190   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3191   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3192   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3193   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3194   right_minus <-- hypreal_add_minus
  3195   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3196   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3197   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3198   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3199   mult_1_right <-- hcomplex_mult_one_right
  3200   mult_zero_left <-- hcomplex_mult_zero_left
  3201   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3202   right_distrib <-- hypnat_add_mult_distrib2
  3203   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3204   right_inverse <-- hypreal_mult_inverse
  3205   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3206   order_refl <-- {hypreal,hypnat}_le_refl
  3207   order_trans <-- {hypreal,hypnat}_le_trans
  3208   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3209   order_less_le <-- {hypreal,hypnat}_less_le
  3210   linorder_linear <-- {hypreal,hypnat}_le_linear
  3211   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3212   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3213   add_nonneg_nonneg <-- hypreal_le_add_order
  3214 
  3215 * Hyperreal: Separate theorems having to do with type-specific
  3216 versions of constants have been merged into theorems that apply to the
  3217 new polymorphic constants (INCOMPATIBILITY):
  3218 
  3219   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3220   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3221   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3222   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3223   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3224   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3225   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3226   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3227   STAR_diff <-- {STAR,STARC}_diff
  3228   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3229     STARC_hcomplex_of_complex}_image_subset
  3230   starset_n_Un <-- starset{Nat,C}_n_Un
  3231   starset_n_Int <-- starset{Nat,C}_n_Int
  3232   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3233   starset_n_diff <-- starset{Nat,C}_n_diff
  3234   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3235   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3236   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3237   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3238   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3239   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3240   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3241   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3242   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3243   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3244   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3245   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3246   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3247   starfun_diff <-- starfun{C,RC,CR}_diff
  3248   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3249   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3250   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3251   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3252   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3253   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3254   starfun_Id <-- starfunC_Id
  3255   starfun_approx <-- starfun{Nat,CR}_approx
  3256   starfun_capprox <-- starfun{C,RC}_capprox
  3257   starfun_abs <-- starfunNat_rabs
  3258   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3259   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3260   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3261   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3262   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3263   starfun_add_approx <-- starfunCR_add_approx
  3264   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3265   starfun_divide <-- starfun{C,CR,RC}_divide
  3266   starfun_n <-- starfun{Nat,C}_n
  3267   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3268   starfun_n_add <-- starfun{Nat,C}_n_add
  3269   starfun_n_add_minus <-- starfunNat_n_add_minus
  3270   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3271   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3272   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3273 
  3274   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3275   star_n_minus <-- {hypreal,hcomplex}_minus
  3276   star_n_diff <-- {hypreal,hcomplex}_diff
  3277   star_n_mult <-- {hypreal,hcomplex}_mult
  3278   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3279   star_n_le <-- {hypreal,hypnat}_le
  3280   star_n_less <-- {hypreal,hypnat}_less
  3281   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3282   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3283   star_n_abs <-- hypreal_hrabs
  3284   star_n_divide <-- hcomplex_divide
  3285 
  3286   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3287   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3288   star_of_diff <-- hypreal_of_real_diff
  3289   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3290   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3291   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3292   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3293   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3294   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3295   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3296   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3297   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3298   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3299   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3300   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3301   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3302   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3303   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3304   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3305   star_of_power <-- hypreal_of_real_power
  3306   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3307 
  3308 * Hyperreal: new method "transfer" that implements the transfer
  3309 principle of nonstandard analysis. With a subgoal that mentions
  3310 nonstandard types like "'a star", the command "apply transfer"
  3311 replaces it with an equivalent one that mentions only standard types.
  3312 To be successful, all free variables must have standard types; non-
  3313 standard variables must have explicit universal quantifiers.
  3314 
  3315 * Hyperreal: A theory of Taylor series.
  3316 
  3317 
  3318 *** HOLCF ***
  3319 
  3320 * Discontinued special version of 'constdefs' (which used to support
  3321 continuous functions) in favor of the general Pure one with full
  3322 type-inference.
  3323 
  3324 * New simplification procedure for solving continuity conditions; it
  3325 is much faster on terms with many nested lambda abstractions (cubic
  3326 instead of exponential time).
  3327 
  3328 * New syntax for domain package: selector names are now optional.
  3329 Parentheses should be omitted unless argument is lazy, for example:
  3330 
  3331   domain 'a stream = cons "'a" (lazy "'a stream")
  3332 
  3333 * New command 'fixrec' for defining recursive functions with pattern
  3334 matching; defining multiple functions with mutual recursion is also
  3335 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3336 sinr, or any data constructor defined by the domain package. The given
  3337 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3338 syntax and examples.
  3339 
  3340 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3341 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3342 but the proof obligation additionally includes an admissibility
  3343 requirement. The packages generate instances of class cpo or pcpo,
  3344 with continuity and strictness theorems for Rep and Abs.
  3345 
  3346 * HOLCF: Many theorems have been renamed according to a more standard naming
  3347 scheme (INCOMPATIBILITY):
  3348 
  3349   foo_inject:  "foo$x = foo$y ==> x = y"
  3350   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3351   foo_less:    "(foo$x << foo$y) = (x << y)"
  3352   foo_strict:  "foo$UU = UU"
  3353   foo_defined: "... ==> foo$x ~= UU"
  3354   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3355 
  3356 
  3357 *** ZF ***
  3358 
  3359 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3360 including the First Isomorphism Theorem (on quotienting by the kernel
  3361 of a homomorphism).
  3362 
  3363 * ZF/Simplifier: install second copy of type solver that actually
  3364 makes use of TC rules declared to Isar proof contexts (or locales);
  3365 the old version is still required for ML proof scripts.
  3366 
  3367 
  3368 *** Cube ***
  3369 
  3370 * Converted to Isar theory format; use locales instead of axiomatic
  3371 theories.
  3372 
  3373 
  3374 *** ML ***
  3375 
  3376 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3377 for ||>, ||>>, |>>,
  3378 
  3379 * Pure/library.ML no longer defines its own option datatype, but uses
  3380 that of the SML basis, which has constructors NONE and SOME instead of
  3381 None and Some, as well as exception Option.Option instead of OPTION.
  3382 The functions the, if_none, is_some, is_none have been adapted
  3383 accordingly, while Option.map replaces apsome.
  3384 
  3385 * Pure/library.ML: the exception LIST has been given up in favour of
  3386 the standard exceptions Empty and Subscript, as well as
  3387 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3388 superceded by the standard hd and tl functions etc.
  3389 
  3390 A number of basic list functions are no longer exported to the ML
  3391 toplevel, as they are variants of predefined functions.  The following
  3392 suggests how one can translate existing code:
  3393 
  3394     rev_append xs ys = List.revAppend (xs, ys)
  3395     nth_elem (i, xs) = List.nth (xs, i)
  3396     last_elem xs = List.last xs
  3397     flat xss = List.concat xss
  3398     seq fs = List.app fs
  3399     partition P xs = List.partition P xs
  3400     mapfilter f xs = List.mapPartial f xs
  3401 
  3402 * Pure/library.ML: several combinators for linear functional
  3403 transformations, notably reverse application and composition:
  3404 
  3405   x |> f                f #> g
  3406   (x, y) |-> f          f #-> g
  3407 
  3408 * Pure/library.ML: introduced/changed precedence of infix operators:
  3409 
  3410   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3411   infix 2 ?;
  3412   infix 3 o oo ooo oooo;
  3413   infix 4 ~~ upto downto;
  3414 
  3415 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3416 infix operators.
  3417 
  3418 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3419 fold_map support linear functional transformations and nesting.  For
  3420 example:
  3421 
  3422   fold f [x1, ..., xN] y =
  3423     y |> f x1 |> ... |> f xN
  3424 
  3425   (fold o fold) f [xs1, ..., xsN] y =
  3426     y |> fold f xs1 |> ... |> fold f xsN
  3427 
  3428   fold f [x1, ..., xN] =
  3429     f x1 #> ... #> f xN
  3430 
  3431   (fold o fold) f [xs1, ..., xsN] =
  3432     fold f xs1 #> ... #> fold f xsN
  3433 
  3434 * Pure/library.ML: the following selectors on type 'a option are
  3435 available:
  3436 
  3437   the:               'a option -> 'a  (*partial*)
  3438   these:             'a option -> 'a  where 'a = 'b list
  3439   the_default: 'a -> 'a option -> 'a
  3440   the_list:          'a option -> 'a list
  3441 
  3442 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3443 basic operations for association lists, following natural argument
  3444 order; moreover the explicit equality predicate passed here avoids
  3445 potentially expensive polymorphic runtime equality checks.
  3446 The old functions may be expressed as follows:
  3447 
  3448   assoc = uncurry (AList.lookup (op =))
  3449   assocs = these oo AList.lookup (op =)
  3450   overwrite = uncurry (AList.update (op =)) o swap
  3451 
  3452 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3453 
  3454   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3455   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3456 
  3457 replacing make_keylist and keyfilter (occassionally used)
  3458 Naive rewrites:
  3459 
  3460   make_keylist = AList.make
  3461   keyfilter = AList.find (op =)
  3462 
  3463 * eq_fst and eq_snd now take explicit equality parameter, thus
  3464   avoiding eqtypes. Naive rewrites:
  3465 
  3466     eq_fst = eq_fst (op =)
  3467     eq_snd = eq_snd (op =)
  3468 
  3469 * Removed deprecated apl and apr (rarely used).
  3470   Naive rewrites:
  3471 
  3472     apl (n, op) =>>= curry op n
  3473     apr (op, m) =>>= fn n => op (n, m)
  3474 
  3475 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3476 provides a reasonably efficient light-weight implementation of sets as
  3477 lists.
  3478 
  3479 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3480 few new operations; existing lookup and update are now curried to
  3481 follow natural argument order (for use with fold etc.);
  3482 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3483 
  3484 * Pure/General: output via the Isabelle channels of
  3485 writeln/warning/error etc. is now passed through Output.output, with a
  3486 hook for arbitrary transformations depending on the print_mode
  3487 (cf. Output.add_mode -- the first active mode that provides a output
  3488 function wins).  Already formatted output may be embedded into further
  3489 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3490 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3491 accommodate easy composition of diagnostic messages etc.  Programmers
  3492 rarely need to care about Output.output or Output.raw at all, with
  3493 some notable exceptions: Output.output is required when bypassing the
  3494 standard channels (writeln etc.), or in token translations to produce
  3495 properly formatted results; Output.raw is required when capturing
  3496 already output material that will eventually be presented to the user
  3497 a second time.  For the default print mode, both Output.output and
  3498 Output.raw have no effect.
  3499 
  3500 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3501 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3502 cumulative results are displayed at the end of a batch session.
  3503 
  3504 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3505 replaced by File.platform_path and File.shell_path (with appropriate
  3506 hooks).  This provides a clean interface for unusual systems where the
  3507 internal and external process view of file names are different.
  3508 
  3509 * Pure: more efficient orders for basic syntactic entities: added
  3510 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3511 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3512 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3513 orders now -- potential INCOMPATIBILITY for code that depends on a
  3514 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3515 Library.sort_strings on result).
  3516 
  3517 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3518 fold_types traverse types/terms from left to right, observing natural
  3519 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3520 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3521 
  3522 * Pure: name spaces have been refined, with significant changes of the
  3523 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3524 to extern(_table).  The plain name entry path is superceded by a
  3525 general 'naming' context, which also includes the 'policy' to produce
  3526 a fully qualified name and external accesses of a fully qualified
  3527 name; NameSpace.extend is superceded by context dependent
  3528 Sign.declare_name.  Several theory and proof context operations modify
  3529 the naming context.  Especially note Theory.restore_naming and
  3530 ProofContext.restore_naming to get back to a sane state; note that
  3531 Theory.add_path is no longer sufficient to recover from
  3532 Theory.absolute_path in particular.
  3533 
  3534 * Pure: new flags short_names (default false) and unique_names
  3535 (default true) for controlling output of qualified names.  If
  3536 short_names is set, names are printed unqualified.  If unique_names is
  3537 reset, the name prefix is reduced to the minimum required to achieve
  3538 the original result when interning again, even if there is an overlap
  3539 with earlier declarations.
  3540 
  3541 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3542 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3543 (useful for printing error messages).  INCOMPATIBILITY.
  3544 
  3545 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3546 Theory.theory are now identified, referring to the universal
  3547 Context.theory (see Pure/context.ML).  Actual signature and theory
  3548 content is managed as theory data.  The old code and interfaces were
  3549 spread over many files and structures; the new arrangement introduces
  3550 considerable INCOMPATIBILITY to gain more clarity:
  3551 
  3552   Context -- theory management operations (name, identity, inclusion,
  3553     parents, ancestors, merge, etc.), plus generic theory data;
  3554 
  3555   Sign -- logical signature and syntax operations (declaring consts,
  3556     types, etc.), plus certify/read for common entities;
  3557 
  3558   Theory -- logical theory operations (stating axioms, definitions,
  3559     oracles), plus a copy of logical signature operations (consts,
  3560     types, etc.); also a few basic management operations (Theory.copy,
  3561     Theory.merge, etc.)
  3562 
  3563 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3564 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3565 for convenience -- they merely return the theory.
  3566 
  3567 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3568 
  3569 * Pure: the Isar proof context type is already defined early in Pure
  3570 as Context.proof (note that ProofContext.context and Proof.context are
  3571 aliases, where the latter is the preferred name).  This enables other
  3572 Isabelle components to refer to that type even before Isar is present.
  3573 
  3574 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3575 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3576 any of these kinds.  For example, Sign.intern typeK is now
  3577 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3578 Theory.hide_types.  Also note that former
  3579 Theory.hide_classes/types/consts are now
  3580 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3581 internalize their arguments!  INCOMPATIBILITY.
  3582 
  3583 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3584 datatype thmref (with constructors Name and NameSelection) instead of
  3585 plain string -- INCOMPATIBILITY;
  3586 
  3587 * Pure: cases produced by proof methods specify options, where NONE
  3588 means to remove case bindings -- INCOMPATIBILITY in
  3589 (RAW_)METHOD_CASES.
  3590 
  3591 * Pure: the following operations retrieve axioms or theorems from a
  3592 theory node or theory hierarchy, respectively:
  3593 
  3594   Theory.axioms_of: theory -> (string * term) list
  3595   Theory.all_axioms_of: theory -> (string * term) list
  3596   PureThy.thms_of: theory -> (string * thm) list
  3597   PureThy.all_thms_of: theory -> (string * thm) list
  3598 
  3599 * Pure: print_tac now outputs the goal through the trace channel.
  3600 
  3601 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3602 Reference Toplevel.debug (default false) controls detailed printing
  3603 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3604 controls execution profiling -- set to 1 for time and 2 for space
  3605 (both increase the runtime).
  3606 
  3607 * Isar session: The initial use of ROOT.ML is now always timed,
  3608 i.e. the log will show the actual process times, in contrast to the
  3609 elapsed wall-clock time that the outer shell wrapper produces.
  3610 
  3611 * Simplifier: improved handling of bound variables (nameless
  3612 representation, avoid allocating new strings).  Simprocs that invoke
  3613 the Simplifier recursively should use Simplifier.inherit_bounds to
  3614 avoid local name clashes.  Failure to do so produces warnings
  3615 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3616 for further details.
  3617 
  3618 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3619 bindings for all theorems stored within a given theory; this may help
  3620 in porting non-Isar theories to Isar ones, while keeping ML proof
  3621 scripts for the time being.
  3622 
  3623 * ML operator HTML.with_charset specifies the charset begin used for
  3624 generated HTML files.  For example:
  3625 
  3626   HTML.with_charset "utf-8" use_thy "Hebrew";
  3627   HTML.with_charset "utf-8" use_thy "Chinese";
  3628 
  3629 
  3630 *** System ***
  3631 
  3632 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3633 isabelle, isatool etc.).
  3634 
  3635 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3636 isatool doc, isatool mkdir, display_drafts etc.).
  3637 
  3638 * isatool usedir: option -f allows specification of the ML file to be
  3639 used by Isabelle; default is ROOT.ML.
  3640 
  3641 * New isatool version outputs the version identifier of the Isabelle
  3642 distribution being used.
  3643 
  3644 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3645 (containing Boolean satisfiability problems) into Isabelle/HOL
  3646 theories.
  3647 
  3648 
  3649 
  3650 New in Isabelle2004 (April 2004)
  3651 --------------------------------
  3652 
  3653 *** General ***
  3654 
  3655 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3656   Replaces linorder.ML.
  3657 
  3658 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3659   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3660   (\<a>...\<z>), are now considered normal letters, and can therefore
  3661   be used anywhere where an ASCII letter (a...zA...Z) has until
  3662   now. COMPATIBILITY: This obviously changes the parsing of some
  3663   terms, especially where a symbol has been used as a binder, say
  3664   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3665   as an identifier.  Fix it by inserting a space around former
  3666   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3667   existing theory and ML files.
  3668 
  3669 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3670 
  3671 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3672   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3673   a normal (but invisible) letter. For multiple letter subscripts repeat
  3674   \<^isub> like this: x\<^isub>1\<^isub>2.
  3675 
  3676 * Pure: There are now sub-/superscripts that can span more than one
  3677   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3678   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3679   superscript. The new control characters are not identifier parts.
  3680 
  3681 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3682   content of "..." to the latex file instead of \isacntrl... . The "..."
  3683   may consist of any printable characters excluding the end bracket >.
  3684 
  3685 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3686   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3687   declare constants "final", which prevents their being given a definition
  3688   later.  It is useful for constants whose behaviour is fixed axiomatically
  3689   rather than definitionally, such as the meta-logic connectives.
  3690 
  3691 * Pure: 'instance' now handles general arities with general sorts
  3692   (i.e. intersections of classes),
  3693 
  3694 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3695   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3696   It can be changed to alter the colors/layout of generated pages.
  3697 
  3698 
  3699 *** Isar ***
  3700 
  3701 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3702   cut_tac, subgoal_tac and thin_tac:
  3703   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3704     locales are no longer forced to write Isar proof scripts.
  3705     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3706     emulations.
  3707   - INCOMPATIBILITY: names of variables to be instantiated may no
  3708     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3709     This is consistent with the instantiation attribute "where".
  3710 
  3711 * Attributes "where" and "of":
  3712   - Now take type variables of instantiated theorem into account when reading
  3713     the instantiation string.  This fixes a bug that caused instantiated
  3714     theorems to have too special types in some circumstances.
  3715   - "where" permits explicit instantiations of type variables.
  3716 
  3717 * Calculation commands "moreover" and "also" no longer interfere with
  3718   current facts ("this"), admitting arbitrary combinations with "then"
  3719   and derived forms.
  3720 
  3721 * Locales:
  3722   - Goal statements involving the context element "includes" no longer
  3723     generate theorems with internal delta predicates (those ending on
  3724     "_axioms") in the premise.
  3725     Resolve particular premise with <locale>.intro to obtain old form.
  3726   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3727     specification and "includes" elements in goal statement.
  3728   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3729     [intro?] and [elim?] (respectively) by default.
  3730   - Experimental command for instantiation of locales in proof contexts:
  3731         instantiate <label>[<attrs>]: <loc>
  3732     Instantiates locale <loc> and adds all its theorems to the current context
  3733     taking into account their attributes.  Label and attrs are optional
  3734     modifiers, like in theorem declarations.  If present, names of
  3735     instantiated theorems are qualified with <label>, and the attributes
  3736     <attrs> are applied after any attributes these theorems might have already.
  3737       If the locale has assumptions, a chained fact of the form
  3738     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3739     are derived.  The command does not support old-style locales declared
  3740     with "locale (open)".
  3741       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3742 
  3743 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3744   (Isar) contexts.
  3745 
  3746 
  3747 *** HOL ***
  3748 
  3749 * Proof import: new image HOL4 contains the imported library from
  3750   the HOL4 system with about 2500 theorems. It is imported by
  3751   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3752   can be used like any other Isabelle image.  See
  3753   HOL/Import/HOL/README for more information.
  3754 
  3755 * Simplifier:
  3756   - Much improved handling of linear and partial orders.
  3757     Reasoners for linear and partial orders are set up for type classes
  3758     "linorder" and "order" respectively, and are added to the default simpset
  3759     as solvers.  This means that the simplifier can build transitivity chains
  3760     to solve goals from the assumptions.
  3761   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3762     of blast or auto after simplification become unnecessary because the goal
  3763     is solved by simplification already.
  3764 
  3765 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3766     all proved in axiomatic type classes for semirings, rings and fields.
  3767 
  3768 * Numerics:
  3769   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3770     now formalized using the Ring_and_Field theory mentioned above.
  3771   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3772     than before, because now they are set up once in a generic manner.
  3773   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3774     Look for the general versions in Ring_and_Field (and Power if they concern
  3775     exponentiation).
  3776 
  3777 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3778 
  3779 * Records:
  3780   - Record types are now by default printed with their type abbreviation
  3781     instead of the list of all field types. This can be configured via
  3782     the reference "print_record_type_abbr".
  3783   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3784     (not enabled by default).
  3785   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3786     EX x. x = sel r to True (not enabled by default).
  3787   - Tactic "record_split_simp_tac" to split and simplify records added.
  3788 
  3789 * 'specification' command added, allowing for definition by
  3790   specification.  There is also an 'ax_specification' command that
  3791   introduces the new constants axiomatically.
  3792 
  3793 * arith(_tac) is now able to generate counterexamples for reals as well.
  3794 
  3795 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3796 
  3797 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3798   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3799 
  3800 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3801   matrix theory to linear programming.
  3802 
  3803 * Unions and Intersections:
  3804   The latex output syntax of UN and INT has been changed
  3805   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3806   i.e. the index formulae has become a subscript.
  3807   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3808 
  3809 * Unions and Intersections over Intervals:
  3810   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3811   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3812   like in normal math, and corresponding versions for < and for intersection.
  3813 
  3814 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3815   lexicographic dictonary ordering has been added as "lexord".
  3816 
  3817 * ML: the legacy theory structures Int and List have been removed. They had
  3818   conflicted with ML Basis Library structures having the same names.
  3819 
  3820 * 'refute' command added to search for (finite) countermodels.  Only works
  3821   for a fragment of HOL.  The installation of an external SAT solver is
  3822   highly recommended.  See "HOL/Refute.thy" for details.
  3823 
  3824 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3825   formulae under an assignment of free variables to random values.
  3826   In contrast to 'refute', it can deal with inductive datatypes,
  3827   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3828   for examples.
  3829 
  3830 
  3831 *** HOLCF ***
  3832 
  3833 * Streams now come with concatenation and are part of the HOLCF image
  3834 
  3835 
  3836 
  3837 New in Isabelle2003 (May 2003)
  3838 ------------------------------
  3839 
  3840 *** General ***
  3841 
  3842 * Provers/simplifier:
  3843 
  3844   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3845     Assumptions are now subject to complete mutual simplification,
  3846     not just from left to right. The simplifier now preserves
  3847     the order of assumptions.
  3848 
  3849     Potential INCOMPATIBILITY:
  3850 
  3851     -- simp sometimes diverges where the old version did
  3852        not, e.g. invoking simp on the goal
  3853 
  3854         [| P (f x); y = x; f x = f y |] ==> Q
  3855 
  3856        now gives rise to the infinite reduction sequence
  3857 
  3858         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3859 
  3860        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3861        kind of problem.
  3862 
  3863     -- Tactics combining classical reasoner and simplification (such as auto)
  3864        are also affected by this change, because many of them rely on
  3865        simp. They may sometimes diverge as well or yield a different numbers
  3866        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3867        in case of problems. Sometimes subsequent calls to the classical
  3868        reasoner will fail because a preceeding call to the simplifier too
  3869        eagerly simplified the goal, e.g. deleted redundant premises.
  3870 
  3871   - The simplifier trace now shows the names of the applied rewrite rules
  3872 
  3873   - You can limit the number of recursive invocations of the simplifier
  3874     during conditional rewriting (where the simplifie tries to solve the
  3875     conditions before applying the rewrite rule):
  3876     ML "simp_depth_limit := n"
  3877     where n is an integer. Thus you can force termination where previously
  3878     the simplifier would diverge.
  3879 
  3880   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3881 
  3882   - No longer aborts on failed congruence proof.  Instead, the
  3883     congruence is ignored.
  3884 
  3885 * Pure: New generic framework for extracting programs from constructive
  3886   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3887   as HOL/Extraction for some case studies.
  3888 
  3889 * Pure: The main goal of the proof state is no longer shown by default, only
  3890 the subgoals. This behaviour is controlled by a new flag.
  3891    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3892 (ML: Proof.show_main_goal).
  3893 
  3894 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3895 rules whose conclusion matches subgoal 1:
  3896       PG menu: Isabelle/Isar -> Show me -> matching rules
  3897 The rules are ordered by how closely they match the subgoal.
  3898 In particular, rules that solve a subgoal outright are displayed first
  3899 (or rather last, the way they are printed).
  3900 (ML: ProofGeneral.print_intros())
  3901 
  3902 * Pure: New flag trace_unify_fail causes unification to print
  3903 diagnostic information (PG: in trace buffer) when it fails. This is
  3904 useful for figuring out why single step proofs like rule, erule or
  3905 assumption failed.
  3906 
  3907 * Pure: Locale specifications now produce predicate definitions
  3908 according to the body of text (covering assumptions modulo local
  3909 definitions); predicate "loc_axioms" covers newly introduced text,
  3910 while "loc" is cumulative wrt. all included locale expressions; the
  3911 latter view is presented only on export into the global theory
  3912 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3913 on the old view without predicates;
  3914 
  3915 * Pure: predefined locales "var" and "struct" are useful for sharing
  3916 parameters (as in CASL, for example); just specify something like
  3917 ``var x + var y + struct M'' as import;
  3918 
  3919 * Pure: improved thms_containing: proper indexing of facts instead of
  3920 raw theorems; check validity of results wrt. current name space;
  3921 include local facts of proof configuration (also covers active
  3922 locales), cover fixed variables in index; may use "_" in term
  3923 specification; an optional limit for the number of printed facts may
  3924 be given (the default is 40);
  3925 
  3926 * Pure: disallow duplicate fact bindings within new-style theory files
  3927 (batch-mode only);
  3928 
  3929 * Provers: improved induct method: assumptions introduced by case
  3930 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3931 the goal statement); "foo" still refers to all facts collectively;
  3932 
  3933 * Provers: the function blast.overloaded has been removed: all constants
  3934 are regarded as potentially overloaded, which improves robustness in exchange
  3935 for slight decrease in efficiency;
  3936 
  3937 * Provers/linorder: New generic prover for transitivity reasoning over
  3938 linear orders.  Note: this prover is not efficient!
  3939 
  3940 * Isar: preview of problems to finish 'show' now produce an error
  3941 rather than just a warning (in interactive mode);
  3942 
  3943 
  3944 *** HOL ***
  3945 
  3946 * arith(_tac)
  3947 
  3948  - Produces a counter example if it cannot prove a goal.
  3949    Note that the counter example may be spurious if the goal is not a formula
  3950    of quantifier-free linear arithmetic.
  3951    In ProofGeneral the counter example appears in the trace buffer.
  3952 
  3953  - Knows about div k and mod k where k is a numeral of type nat or int.
  3954 
  3955  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3956    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3957    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3958 
  3959 * simp's arithmetic capabilities have been enhanced a bit: it now
  3960 takes ~= in premises into account (by performing a case split);
  3961 
  3962 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3963 are distributed over a sum of terms;
  3964 
  3965 * New tactic "trans_tac" and method "trans" instantiate
  3966 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3967 "<=", "<" and "=").
  3968 
  3969 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3970 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3971 
  3972 * 'typedef' command has new option "open" to suppress the set
  3973 definition;
  3974 
  3975 * functions Min and Max on finite sets have been introduced (theory
  3976 Finite_Set);
  3977 
  3978 * attribute [symmetric] now works for relations as well; it turns
  3979 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3980 
  3981 * induct over a !!-quantified statement (say !!x1..xn):
  3982   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3983 
  3984 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3985 %x. None. Warning: empty_def now refers to the previously hidden definition
  3986 of the empty set.
  3987 
  3988 * Algebra: formalization of classical algebra.  Intended as base for
  3989 any algebraic development in Isabelle.  Currently covers group theory
  3990 (up to Sylow's theorem) and ring theory (Universal Property of
  3991 Univariate Polynomials).  Contributions welcome;
  3992 
  3993 * GroupTheory: deleted, since its material has been moved to Algebra;
  3994 
  3995 * Complex: new directory of the complex numbers with numeric constants,
  3996 nonstandard complex numbers, and some complex analysis, standard and
  3997 nonstandard (Jacques Fleuriot);
  3998 
  3999 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4000 
  4001 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4002 Fleuriot);
  4003 
  4004 * Real/HahnBanach: updated and adapted to locales;
  4005 
  4006 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4007 Gray and Kramer);
  4008 
  4009 * UNITY: added the Meier-Sanders theory of progress sets;
  4010 
  4011 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4012 as abstract algorithms, instantiated to the JVM;
  4013 
  4014 * Bali: Java source language formalization. Type system, operational
  4015 semantics, axiomatic semantics. Supported language features:
  4016 classes, interfaces, objects,virtual methods, static methods,
  4017 static/instance fields, arrays, access modifiers, definite
  4018 assignment, exceptions.
  4019 
  4020 
  4021 *** ZF ***
  4022 
  4023 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4024 universe, etc.);
  4025 
  4026 * Main ZF: virtually all theories converted to new-style format;
  4027 
  4028 
  4029 *** ML ***
  4030 
  4031 * Pure: Tactic.prove provides sane interface for internal proofs;
  4032 omits the infamous "standard" operation, so this is more appropriate
  4033 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4034 
  4035 * Pure: improved error reporting of simprocs;
  4036 
  4037 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4038 up simprocs;
  4039 
  4040 
  4041 *** Document preparation ***
  4042 
  4043 * uses \par instead of \\ for line breaks in theory text. This may
  4044 shift some page breaks in large documents. To get the old behaviour
  4045 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4046 
  4047 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4048 other packages
  4049 
  4050 * \<euro> now needs package babel/greek instead of marvosym (which
  4051 broke \Rightarrow)
  4052 
  4053 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4054 textcomp package)
  4055 
  4056 
  4057 
  4058 New in Isabelle2002 (March 2002)
  4059 --------------------------------
  4060 
  4061 *** Document preparation ***
  4062 
  4063 * greatly simplified document preparation setup, including more
  4064 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4065 instructive isatool mkdir; users should basically be able to get
  4066 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4067 users may run a separate document processing stage manually like this:
  4068 "isatool usedir -D output HOL Test && isatool document Test/output";
  4069 
  4070 * theory dependency graph may now be incorporated into documents;
  4071 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4072 with \includegraphics of LaTeX;
  4073 
  4074 * proper spacing of consecutive markup elements, especially text
  4075 blocks after section headings;
  4076 
  4077 * support bold style (for single symbols only), input syntax is like
  4078 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4079 
  4080 * \<bullet> is now output as bold \cdot by default, which looks much
  4081 better in printed text;
  4082 
  4083 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4084 note that these symbols are currently unavailable in Proof General /
  4085 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4086 
  4087 * isatool latex no longer depends on changed TEXINPUTS, instead
  4088 isatool document copies the Isabelle style files to the target
  4089 location;
  4090 
  4091 
  4092 *** Isar ***
  4093 
  4094 * Pure/Provers: improved proof by cases and induction;
  4095   - 'case' command admits impromptu naming of parameters (such as
  4096     "case (Suc n)");
  4097   - 'induct' method divinates rule instantiation from the inductive
  4098     claim; no longer requires excessive ?P bindings for proper
  4099     instantiation of cases;
  4100   - 'induct' method properly enumerates all possibilities of set/type
  4101     rules; as a consequence facts may be also passed through *type*
  4102     rules without further ado;
  4103   - 'induct' method now derives symbolic cases from the *rulified*
  4104     rule (before it used to rulify cases stemming from the internal
  4105     atomized version); this means that the context of a non-atomic
  4106     statement becomes is included in the hypothesis, avoiding the
  4107     slightly cumbersome show "PROP ?case" form;
  4108   - 'induct' may now use elim-style induction rules without chaining
  4109     facts, using ``missing'' premises from the goal state; this allows
  4110     rules stemming from inductive sets to be applied in unstructured
  4111     scripts, while still benefitting from proper handling of non-atomic
  4112     statements; NB: major inductive premises need to be put first, all
  4113     the rest of the goal is passed through the induction;
  4114   - 'induct' proper support for mutual induction involving non-atomic
  4115     rule statements (uses the new concept of simultaneous goals, see
  4116     below);
  4117   - append all possible rule selections, but only use the first
  4118     success (no backtracking);
  4119   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4120   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4121   - added 'print_induct_rules' (covered by help item in recent Proof
  4122     General versions);
  4123   - moved induct/cases attributes to Pure, methods to Provers;
  4124   - generic method setup instantiated for FOL and HOL;
  4125 
  4126 * Pure: support multiple simultaneous goal statements, for example
  4127 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4128 meta-level mechanism, this acts as if several individual goals had
  4129 been stated separately; in particular common proof methods need to be
  4130 repeated in order to cover all claims; note that a single elimination
  4131 step is *not* sufficient to establish the two conjunctions, so this
  4132 fails:
  4133 
  4134   assume "A & B" then have A and B ..   (*".." fails*)
  4135 
  4136 better use "obtain" in situations as above; alternative refer to
  4137 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4138 
  4139 * Pure: proper integration with ``locales''; unlike the original
  4140 version by Florian Kammller, Isar locales package high-level proof
  4141 contexts rather than raw logical ones (e.g. we admit to include
  4142 attributes everywhere); operations on locales include merge and
  4143 rename; support for implicit arguments (``structures''); simultaneous
  4144 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4145 some examples;
  4146 
  4147 * Pure: the following commands have been ``localized'', supporting a
  4148 target locale specification "(in name)": 'lemma', 'theorem',
  4149 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4150 stored both within the locale and at the theory level (exported and
  4151 qualified by the locale name);
  4152 
  4153 * Pure: theory goals may now be specified in ``long'' form, with
  4154 ad-hoc contexts consisting of arbitrary locale elements. for example
  4155 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4156 definitions may be given, too); the result is a meta-level rule with
  4157 the context elements being discharged in the obvious way;
  4158 
  4159 * Pure: new proof command 'using' allows to augment currently used
  4160 facts after a goal statement ('using' is syntactically analogous to
  4161 'apply', but acts on the goal's facts only); this allows chained facts
  4162 to be separated into parts given before and after a claim, as in
  4163 ``from a and b have C using d and e <proof>'';
  4164 
  4165 * Pure: renamed "antecedent" case to "rule_context";
  4166 
  4167 * Pure: new 'judgment' command records explicit information about the
  4168 object-logic embedding (used by several tools internally); no longer
  4169 use hard-wired "Trueprop";
  4170 
  4171 * Pure: added 'corollary' command;
  4172 
  4173 * Pure: fixed 'token_translation' command;
  4174 
  4175 * Pure: removed obsolete 'exported' attribute;
  4176 
  4177 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4178 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4179 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4180 
  4181 * Pure: method 'atomize' presents local goal premises as object-level
  4182 statements (atomic meta-level propositions); setup controlled via
  4183 rewrite rules declarations of 'atomize' attribute; example
  4184 application: 'induct' method with proper rule statements in improper
  4185 proof *scripts*;
  4186 
  4187 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4188 now consider the syntactic context of assumptions, giving a better
  4189 chance to get type-inference of the arguments right (this is
  4190 especially important for locales);
  4191 
  4192 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4193 mode;
  4194 
  4195 * Pure/obtain: the formal conclusion "thesis", being marked as
  4196 ``internal'', may no longer be reference directly in the text;
  4197 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4198 situations;
  4199 
  4200 * Pure: generic 'sym' attribute which declares a rule both as pure
  4201 'elim?' and for the 'symmetric' operation;
  4202 
  4203 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4204 text; the fixed correlation with particular command syntax has been
  4205 discontinued;
  4206 
  4207 * Pure: new method 'rules' is particularly well-suited for proof
  4208 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4209 but often produces more compact proof terms with less detours;
  4210 
  4211 * Pure/Provers/classical: simplified integration with pure rule
  4212 attributes and methods; the classical "intro?/elim?/dest?"
  4213 declarations coincide with the pure ones; the "rule" method no longer
  4214 includes classically swapped intros; "intro" and "elim" methods no
  4215 longer pick rules from the context; also got rid of ML declarations
  4216 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4217 INCOMPATIBILITY;
  4218 
  4219 * Provers/classical: attribute 'swapped' produces classical inversions
  4220 of introduction rules;
  4221 
  4222 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4223 rules instead of full simplifier context; 'iff' attribute handles
  4224 conditional rules;
  4225 
  4226 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4227 
  4228 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4229 "(permissive)" option to recover old behavior;
  4230 
  4231 * HOL: 'inductive' no longer features separate (collective) attributes
  4232 for 'intros' (was found too confusing);
  4233 
  4234 * HOL: properly declared induction rules less_induct and
  4235 wf_induct_rule;
  4236 
  4237 
  4238 *** HOL ***
  4239 
  4240 * HOL: moved over to sane numeral syntax; the new policy is as
  4241 follows:
  4242 
  4243   - 0 and 1 are polymorphic constants, which are defined on any
  4244   numeric type (nat, int, real etc.);
  4245 
  4246   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4247   binary representation internally;
  4248 
  4249   - type nat has special constructor Suc, and generally prefers Suc 0
  4250   over 1::nat and Suc (Suc 0) over 2::nat;
  4251 
  4252 This change may cause significant problems of INCOMPATIBILITY; here
  4253 are some hints on converting existing sources:
  4254 
  4255   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4256   entities, so expressions involving "-" (unary or binary minus) need
  4257   to be spaced properly;
  4258 
  4259   - existing occurrences of "1" may need to be constraint "1::nat" or
  4260   even replaced by Suc 0; similar for old "2";
  4261 
  4262   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4263 
  4264   - remove all special provisions on numerals in proofs;
  4265 
  4266 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4267 representation (depends on bin_arith_simps in the default context);
  4268 
  4269 * HOL: symbolic syntax for x^2 (numeral 2);
  4270 
  4271 * HOL: the class of all HOL types is now called "type" rather than
  4272 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4273 in axclass/classes, instance/arities, and (usually rare) occurrences
  4274 in typings (of consts etc.); internally the class is called
  4275 "HOL.type", ML programs should refer to HOLogic.typeS;
  4276 
  4277 * HOL/record package improvements:
  4278   - new derived operations "fields" to build a partial record section,
  4279     "extend" to promote a fixed record to a record scheme, and
  4280     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4281     declared as simp by default;
  4282   - shared operations ("more", "fields", etc.) now need to be always
  4283     qualified) --- potential INCOMPATIBILITY;
  4284   - removed "make_scheme" operations (use "make" with "extend") --
  4285     INCOMPATIBILITY;
  4286   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4287   - provides cases/induct rules for use with corresponding Isar
  4288     methods (for concrete records, record schemes, concrete more
  4289     parts, and schematic more parts -- in that order);
  4290   - internal definitions directly based on a light-weight abstract
  4291     theory of product types over typedef rather than datatype;
  4292 
  4293 * HOL: generic code generator for generating executable ML code from
  4294 specifications; specific support for HOL constructs such as inductive
  4295 datatypes and sets, as well as recursive functions; can be invoked
  4296 via 'generate_code' theory section;
  4297 
  4298 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4299 
  4300 * HOL: consolidated and renamed several theories.  In particular:
  4301         Ord.thy has been absorbed into HOL.thy
  4302         String.thy has been absorbed into List.thy
  4303 
  4304 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4305 (beware of argument permutation!);
  4306 
  4307 * HOL: linorder_less_split superseded by linorder_cases;
  4308 
  4309 * HOL/List: "nodups" renamed to "distinct";
  4310 
  4311 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4312 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4313   - Ex_def has changed, now need to use some_eq_ex
  4314 
  4315 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4316 in this (rare) case use:
  4317 
  4318   delSWrapper "split_all_tac"
  4319   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4320 
  4321 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4322 MAY FAIL;
  4323 
  4324 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4325 Isabelle's type classes, ^ on functions and relations has too general
  4326 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4327 necessary to attach explicit type constraints;
  4328 
  4329 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4330 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4331 renamed accordingly (eg "compI" -> "rel_compI").
  4332 
  4333 * HOL: syntax translations now work properly with numerals and records
  4334 expressions;
  4335 
  4336 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4337 of "lam" -- INCOMPATIBILITY;
  4338 
  4339 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4340 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4341 renamed "Product_Type.unit";
  4342 
  4343 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4344 
  4345 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4346 the "cases" method);
  4347 
  4348 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4349 Florian Kammller);
  4350 
  4351 * HOL/IMP: updated and converted to new-style theory format; several
  4352 parts turned into readable document, with proper Isar proof texts and
  4353 some explanations (by Gerwin Klein);
  4354 
  4355 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4356 
  4357 * HOL-Hyperreal is now a logic image;
  4358 
  4359 
  4360 *** HOLCF ***
  4361 
  4362 * Isar: consts/constdefs supports mixfix syntax for continuous
  4363 operations;
  4364 
  4365 * Isar: domain package adapted to new-style theory format, e.g. see
  4366 HOLCF/ex/Dnat.thy;
  4367 
  4368 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4369 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4370 lift.induct_tac, always use UU instead of Undef;
  4371 
  4372 * HOLCF/IMP: updated and converted to new-style theory;
  4373 
  4374 
  4375 *** ZF ***
  4376 
  4377 * Isar: proper integration of logic-specific tools and packages,
  4378 including theory commands '(co)inductive', '(co)datatype',
  4379 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4380 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4381 
  4382 * theory Main no longer includes AC; for the Axiom of Choice, base
  4383 your theory on Main_ZFC;
  4384 
  4385 * the integer library now covers quotients and remainders, with many
  4386 laws relating division to addition, multiplication, etc.;
  4387 
  4388 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4389 typeless version of the formalism;
  4390 
  4391 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4392 format;
  4393 
  4394 * ZF/Induct: new directory for examples of inductive definitions,
  4395 including theory Multiset for multiset orderings; converted to
  4396 new-style theory format;
  4397 
  4398 * ZF: many new theorems about lists, ordinals, etc.;
  4399 
  4400 
  4401 *** General ***
  4402 
  4403 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4404 variable proof controls level of detail: 0 = no proofs (only oracle
  4405 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4406 also ref manual for further ML interfaces;
  4407 
  4408 * Pure/axclass: removed obsolete ML interface
  4409 goal_subclass/goal_arity;
  4410 
  4411 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4412 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4413 separate tokens, so expressions involving minus need to be spaced
  4414 properly;
  4415 
  4416 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4417 rather than "infixl" or "infixr";
  4418 
  4419 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4420 sort constraint specifications in type inference; e.g. "x::_::foo"
  4421 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4422 type variable);
  4423 
  4424 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4425 control output of nested => (types); the default behavior is
  4426 "type_brackets";
  4427 
  4428 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4429 tokens into AST constants;
  4430 
  4431 * Pure/syntax: prefer later declarations of translations and print
  4432 translation functions; potential INCOMPATIBILITY: need to reverse
  4433 multiple declarations for same syntax element constant;
  4434 
  4435 * Pure/show_hyps reset by default (in accordance to existing Isar
  4436 practice);
  4437 
  4438 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4439 addSafter;
  4440 
  4441 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4442 as well;
  4443 
  4444 * system: tested support for MacOS X; should be able to get Isabelle +
  4445 Proof General to work in a plain Terminal after installing Poly/ML
  4446 (e.g. from the Isabelle distribution area) and GNU bash alone
  4447 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4448 support requires further installations, e.g. from
  4449 http://fink.sourceforge.net/);
  4450 
  4451 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4452 
  4453 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4454 of 40 MB), cf. ML_OPTIONS;
  4455 
  4456 * system: Proof General keywords specification is now part of the
  4457 Isabelle distribution (see etc/isar-keywords.el);
  4458 
  4459 * system: support for persistent Proof General sessions (refrain from
  4460 outdating all loaded theories on startup); user may create writable
  4461 logic images like this: ``isabelle -q HOL Test'';
  4462 
  4463 * system: smart selection of Isabelle process versus Isabelle
  4464 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4465 run both "isabelle" and "Isabelle" even if file names are badly
  4466 damaged (executable inspects the case of the first letter of its own
  4467 name); added separate "isabelle-process" and "isabelle-interface";
  4468 
  4469 * system: refrain from any attempt at filtering input streams; no
  4470 longer support ``8bit'' encoding of old isabelle font, instead proper
  4471 iso-latin characters may now be used; the related isatools
  4472 "symbolinput" and "nonascii" have disappeared as well;
  4473 
  4474 * system: removed old "xterm" interface (the print modes "xterm" and
  4475 "xterm_color" are still available for direct use in a suitable
  4476 terminal);
  4477 
  4478 
  4479 
  4480 New in Isabelle99-2 (February 2001)
  4481 -----------------------------------
  4482 
  4483 *** Overview of INCOMPATIBILITIES ***
  4484 
  4485 * HOL: please note that theories in the Library and elsewhere often use the
  4486 new-style (Isar) format; to refer to their theorems in an ML script you must
  4487 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4488 
  4489 * HOL: inductive package no longer splits induction rule aggressively,
  4490 but only as far as specified by the introductions given; the old
  4491 format may be recovered via ML function complete_split_rule or attribute
  4492 'split_rule (complete)';
  4493 
  4494 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4495 gfp_Tarski to gfp_unfold;
  4496 
  4497 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4498 
  4499 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4500 relation); infix "^^" has been renamed "``"; infix "``" has been
  4501 renamed "`"; "univalent" has been renamed "single_valued";
  4502 
  4503 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4504 operation;
  4505 
  4506 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4507 
  4508 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4509 
  4510 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4511 consequence, it is no longer monotonic wrt. the local goal context
  4512 (which is now passed through the inductive cases);
  4513 
  4514 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4515 \<gg> to \<ggreater>;
  4516 
  4517 
  4518 *** Document preparation ***
  4519 
  4520 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4521 available: are "it" for near math-mode best-style output, "sl" for
  4522 slanted text style, and "tt" for plain type-writer; if no
  4523 \isabellestyle command is given, output is according to slanted
  4524 type-writer);
  4525 
  4526 * support sub/super scripts (for single symbols only), input syntax is
  4527 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4528 
  4529 * some more standard symbols; see Appendix A of the system manual for
  4530 the complete list of symbols defined in isabellesym.sty;
  4531 
  4532 * improved isabelle style files; more abstract symbol implementation
  4533 (should now use \isamath{...} and \isatext{...} in custom symbol
  4534 definitions);
  4535 
  4536 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4537 state; Note that presentation of goal states does not conform to
  4538 actual human-readable proof documents.  Please do not include goal
  4539 states into document output unless you really know what you are doing!
  4540 
  4541 * proper indentation of antiquoted output with proportional LaTeX
  4542 fonts;
  4543 
  4544 * no_document ML operator temporarily disables LaTeX document
  4545 generation;
  4546 
  4547 * isatool unsymbolize tunes sources for plain ASCII communication;
  4548 
  4549 
  4550 *** Isar ***
  4551 
  4552 * Pure: Isar now suffers initial goal statements to contain unbound
  4553 schematic variables (this does not conform to actual readable proof
  4554 documents, due to unpredictable outcome and non-compositional proof
  4555 checking); users who know what they are doing may use schematic goals
  4556 for Prolog-style synthesis of proven results;
  4557 
  4558 * Pure: assumption method (an implicit finishing) now handles actual
  4559 rules as well;
  4560 
  4561 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4562 initial goal, declare "that" only as Pure intro (only for single
  4563 steps); the "that" rule assumption may now be involved in implicit
  4564 finishing, thus ".." becomes a feasible for trivial obtains;
  4565 
  4566 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4567 instance proofs may be performed by "..";
  4568 
  4569 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4570 statements as well;
  4571 
  4572 * Pure: more robust selection of calculational rules;
  4573 
  4574 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4575 rule (as well as the assumption rule);
  4576 
  4577 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4578 lemmas, using the graph browser tool;
  4579 
  4580 * Pure: predict failure of "show" in interactive mode;
  4581 
  4582 * Pure: 'thms_containing' now takes actual terms as arguments;
  4583 
  4584 * HOL: improved method 'induct' --- now handles non-atomic goals
  4585 (potential INCOMPATIBILITY); tuned error handling;
  4586 
  4587 * HOL: cases and induct rules now provide explicit hints about the
  4588 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4589 any remaining facts are inserted into the goal verbatim;
  4590 
  4591 * HOL: local contexts (aka cases) may now contain term bindings as
  4592 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4593 the result to be shown in each case;
  4594 
  4595 * HOL: added 'recdef_tc' command;
  4596 
  4597 * isatool convert assists in eliminating legacy ML scripts;
  4598 
  4599 
  4600 *** HOL ***
  4601 
  4602 * HOL/Library: a collection of generic theories to be used together
  4603 with main HOL; the theory loader path already includes this directory
  4604 by default; the following existing theories have been moved here:
  4605 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4606 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4607 
  4608 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4609 modelling and verification task performed in Isabelle/HOL +
  4610 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4611 
  4612 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4613 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4614 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4615 'domain', this makes the theory consistent with mathematical
  4616 literature;
  4617 
  4618 * HOL basics: added overloaded operations "inverse" and "divide"
  4619 (infix "/"), syntax for generic "abs" operation, generic summation
  4620 operator \<Sum>;
  4621 
  4622 * HOL/typedef: simplified package, provide more useful rules (see also
  4623 HOL/subset.thy);
  4624 
  4625 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4626 now expressed as a proper nested rule (old-style tactic scripts may
  4627 require atomize_strip_tac to cope with non-atomic premises);
  4628 
  4629 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4630 to "split_conv" (old name still available for compatibility);
  4631 
  4632 * HOL: improved concrete syntax for strings (e.g. allows translation
  4633 rules with string literals);
  4634 
  4635 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4636  and Fleuriot's mechanization of analysis, including the transcendental
  4637  functions for the reals;
  4638 
  4639 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4640 
  4641 
  4642 *** CTT ***
  4643 
  4644 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4645 "lam" is displayed as TWO lambda-symbols
  4646 
  4647 * CTT: theory Main now available, containing everything (that is, Bool
  4648 and Arith);
  4649 
  4650 
  4651 *** General ***
  4652 
  4653 * Pure: the Simplifier has been implemented properly as a derived rule
  4654 outside of the actual kernel (at last!); the overall performance
  4655 penalty in practical applications is about 50%, while reliability of
  4656 the Isabelle inference kernel has been greatly improved;
  4657 
  4658 * print modes "brackets" and "no_brackets" control output of nested =>
  4659 (types) and ==> (props); the default behaviour is "brackets";
  4660 
  4661 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4662 as assumptions as well;
  4663 
  4664 * system: support Poly/ML 4.0;
  4665 
  4666 * system: isatool install handles KDE version 1 or 2;
  4667 
  4668 
  4669 
  4670 New in Isabelle99-1 (October 2000)
  4671 ----------------------------------
  4672 
  4673 *** Overview of INCOMPATIBILITIES ***
  4674 
  4675 * HOL: simplification of natural numbers is much changed; to partly
  4676 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4677 issue the following ML commands:
  4678 
  4679   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4680   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4681 
  4682 * HOL: simplification no longer dives into case-expressions; this is
  4683 controlled by "t.weak_case_cong" for each datatype t;
  4684 
  4685 * HOL: nat_less_induct renamed to less_induct;
  4686 
  4687 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4688 fixsome to patch .thy and .ML sources automatically;
  4689 
  4690   select_equality  -> some_equality
  4691   select_eq_Ex     -> some_eq_ex
  4692   selectI2EX       -> someI2_ex
  4693   selectI2         -> someI2
  4694   selectI          -> someI
  4695   select1_equality -> some1_equality
  4696   Eps_sym_eq       -> some_sym_eq_trivial
  4697   Eps_eq           -> some_eq_trivial
  4698 
  4699 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4700 
  4701 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4702 instead);
  4703 
  4704 * HOL: the recursion equations generated by 'recdef' are now called
  4705 f.simps instead of f.rules;
  4706 
  4707 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4708 
  4709 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4710 sometimes be needed;
  4711 
  4712 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4713 
  4714 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4715 
  4716 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4717 product is now "<*>" instead of "Times"; the lexicographic product is
  4718 now "<*lex*>" instead of "**";
  4719 
  4720 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4721 of main HOL, but was unused); better use HOL's datatype package;
  4722 
  4723 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4724 the old syntax may be recovered as follows:
  4725 
  4726   syntax (symbols)
  4727     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4728       (infixl "\\<oplus>" 100)
  4729 
  4730 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4731 
  4732 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4733 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4734 internally;
  4735 
  4736 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4737 changed from A/r to A//r;
  4738 
  4739 * ZF: new treatment of arithmetic (nat & int) may break some old
  4740 proofs;
  4741 
  4742 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4743 rulify -> rule_format, elimify -> elim_format, ...);
  4744 
  4745 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4746 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4747 should have to change intro!! to intro? only); replaced "delrule" by
  4748 "rule del";
  4749 
  4750 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4751 
  4752 * Provers: strengthened force_tac by using new first_best_tac;
  4753 
  4754 * LaTeX document preparation: several changes of isabelle.sty (see
  4755 lib/texinputs);
  4756 
  4757 
  4758 *** Document preparation ***
  4759 
  4760 * formal comments (text blocks etc.) in new-style theories may now
  4761 contain antiquotations of thm/prop/term/typ/text to be presented
  4762 according to latex print mode; concrete syntax is like this:
  4763 @{term[show_types] "f(x) = a + x"};
  4764 
  4765 * isatool mkdir provides easy setup of Isabelle session directories,
  4766 including proper document sources;
  4767 
  4768 * generated LaTeX sources are now deleted after successful run
  4769 (isatool document -c); may retain a copy somewhere else via -D option
  4770 of isatool usedir;
  4771 
  4772 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4773 style files, achieving self-contained LaTeX sources and simplifying
  4774 LaTeX debugging;
  4775 
  4776 * old-style theories now produce (crude) LaTeX output as well;
  4777 
  4778 * browser info session directories are now self-contained (may be put
  4779 on WWW server seperately); improved graphs of nested sessions; removed
  4780 graph for 'all sessions';
  4781 
  4782 * several improvements in isabelle style files; \isabellestyle{it}
  4783 produces fake math mode output; \isamarkupheader is now \section by
  4784 default; see lib/texinputs/isabelle.sty etc.;
  4785 
  4786 
  4787 *** Isar ***
  4788 
  4789 * Isar/Pure: local results and corresponding term bindings are now
  4790 subject to Hindley-Milner polymorphism (similar to ML); this
  4791 accommodates incremental type-inference very nicely;
  4792 
  4793 * Isar/Pure: new derived language element 'obtain' supports
  4794 generalized existence reasoning;
  4795 
  4796 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4797 support accumulation of results, without applying any rules yet;
  4798 useful to collect intermediate results without explicit name
  4799 references, and for use with transitivity rules with more than 2
  4800 premises;
  4801 
  4802 * Isar/Pure: scalable support for case-analysis type proofs: new
  4803 'case' language element refers to local contexts symbolically, as
  4804 produced by certain proof methods; internally, case names are attached
  4805 to theorems as "tags";
  4806 
  4807 * Isar/Pure: theory command 'hide' removes declarations from
  4808 class/type/const name spaces;
  4809 
  4810 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4811 indicate potential overloading;
  4812 
  4813 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4814 
  4815 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4816 "{a,b,c}" instead of {a,b,c};
  4817 
  4818 * Isar/Pure now provides its own version of intro/elim/dest
  4819 attributes; useful for building new logics, but beware of confusion
  4820 with the version in Provers/classical;
  4821 
  4822 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4823 case name 'antecedent';
  4824 
  4825 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4826 to the current context is now done automatically);
  4827 
  4828 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4829 for definining proof methods in ML;
  4830 
  4831 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4832 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4833 most cases, one should have to change intro!! to intro? only);
  4834 replaced "delrule" by "rule del";
  4835 
  4836 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4837 'symmetric' attribute (the latter supercedes [RS sym]);
  4838 
  4839 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4840 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4841 well (including splits);
  4842 
  4843 * Isar/Provers: Simplifier and Classical methods now support all kind
  4844 of modifiers used in the past, including 'cong', 'iff', etc.
  4845 
  4846 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4847 of Simplifier and Classical reasoner);
  4848 
  4849 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4850 now support named cases; major packages (inductive, datatype, primrec,
  4851 recdef) support case names and properly name parameters;
  4852 
  4853 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4854 monotonicity conditions are extracted to be proven at end of
  4855 calculations;
  4856 
  4857 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4858 method anyway;
  4859 
  4860 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4861 split_if split_if_asm; datatype package provides theorems foo.splits =
  4862 foo.split foo.split_asm for each datatype;
  4863 
  4864 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4865 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4866 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4867 use "(cases (simplified))" method in proper proof texts);
  4868 
  4869 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4870 
  4871 * Isar: names of theorems etc. may be natural numbers as well;
  4872 
  4873 * Isar: 'pr' command: optional arguments for goals_limit and
  4874 ProofContext.prems_limit; no longer prints theory contexts, but only
  4875 proof states;
  4876 
  4877 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4878 additional print modes to be specified; e.g. "pr(latex)" will print
  4879 proof state according to the Isabelle LaTeX style;
  4880 
  4881 * Isar: improved support for emulating tactic scripts, including proof
  4882 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4883 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4884 (for HOL datatypes);
  4885 
  4886 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4887 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4888 'proof method scripts' have to be in depth-first order;
  4889 
  4890 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4891 
  4892 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4893 should instead use individual commands for printing items
  4894 (print_commands, print_methods etc.);
  4895 
  4896 * Isar: added 'nothing' --- the empty list of theorems;
  4897 
  4898 
  4899 *** HOL ***
  4900 
  4901 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4902 corresponding virtual machine and a specification of its bytecode
  4903 verifier and a lightweight bytecode verifier, including proofs of
  4904 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4905 Cornelia Pusch (see also the homepage of project Bali at
  4906 http://isabelle.in.tum.de/Bali/);
  4907 
  4908 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4909 Clemens Ballarin;
  4910 
  4911 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4912 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4913 Rasmussen;
  4914 
  4915 * HOL/Lattice: fundamental concepts of lattice theory and order
  4916 structures, including duals, properties of bounds versus algebraic
  4917 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4918 Theorem for complete lattices etc.; may also serve as a demonstration
  4919 for abstract algebraic reasoning using axiomatic type classes, and
  4920 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4921 
  4922 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4923 von Oheimb;
  4924 
  4925 * HOL/IMPP: extension of IMP with local variables and mutually
  4926 recursive procedures, by David von Oheimb;
  4927 
  4928 * HOL/Lambda: converted into new-style theory and document;
  4929 
  4930 * HOL/ex/Multiquote: example of multiple nested quotations and
  4931 anti-quotations -- basically a generalized version of de-Bruijn
  4932 representation; very useful in avoiding lifting of operations;
  4933 
  4934 * HOL/record: added general record equality rule to simpset; fixed
  4935 select-update simplification procedure to handle extended records as
  4936 well; admit "r" as field name;
  4937 
  4938 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4939 other numeric types and also as the identity of groups, rings, etc.;
  4940 
  4941 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4942 Types nat and int belong to this axclass;
  4943 
  4944 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4945    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4946    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4947   two terms #m*u and #n*u are replaced by #(m+n)*u
  4948     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4949   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4950     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4951 
  4952 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4953 powerful prover for predicate logic but knows nothing of clasets; see
  4954 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4955 
  4956 * HOL: new version of "case_tac" subsumes both boolean case split and
  4957 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4958 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4959 
  4960 * HOL: simplification no longer dives into case-expressions: only the
  4961 selector expression is simplified, but not the remaining arms; to
  4962 enable full simplification of case-expressions for datatype t, you may
  4963 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4964 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4965 
  4966 * HOL/recdef: the recursion equations generated by 'recdef' for
  4967 function 'f' are now called f.simps instead of f.rules; if all
  4968 termination conditions are proved automatically, these simplification
  4969 rules are added to the simpset, as in primrec; rules may be named
  4970 individually as well, resulting in a separate list of theorems for
  4971 each equation;
  4972 
  4973 * HOL/While is a new theory that provides a while-combinator. It
  4974 permits the definition of tail-recursive functions without the
  4975 provision of a termination measure. The latter is necessary once the
  4976 invariant proof rule for while is applied.
  4977 
  4978 * HOL: new (overloaded) notation for the set of elements below/above
  4979 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4980 
  4981 * HOL: theorems impI, allI, ballI bound as "strip";
  4982 
  4983 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4984 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4985 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4986 
  4987 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4988 
  4989 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4990 main HOL, but was unused);
  4991 
  4992 * HOL: fewer consts declared as global (e.g. have to refer to
  4993 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4994 
  4995 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4996 in case of overlap with user translations (e.g. judgements over
  4997 tuples); (note that the underlying logical represenation is still
  4998 bogus);
  4999 
  5000 
  5001 *** ZF ***
  5002 
  5003 * ZF: simplification automatically cancels common terms in arithmetic
  5004 expressions over nat and int;
  5005 
  5006 * ZF: new treatment of nat to minimize type-checking: all operators
  5007 coerce their operands to a natural number using the function natify,
  5008 making the algebraic laws unconditional;
  5009 
  5010 * ZF: as above, for int: operators coerce their operands to an integer
  5011 using the function intify;
  5012 
  5013 * ZF: the integer library now contains many of the usual laws for the
  5014 orderings, including $<=, and monotonicity laws for $+ and $*;
  5015 
  5016 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5017 simplification;
  5018 
  5019 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5020 to the simplifier and classical reasoner simultaneously;
  5021 
  5022 
  5023 *** General ***
  5024 
  5025 * Provers: blast_tac now handles actual object-logic rules as
  5026 assumptions; note that auto_tac uses blast_tac internally as well;
  5027 
  5028 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5029 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5030 
  5031 * Provers: delrules now handles destruct rules as well (no longer need
  5032 explicit make_elim);
  5033 
  5034 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5035   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5036 use instead the strong form,
  5037   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5038 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5039 from destruct-rules;
  5040 
  5041 * Provers: Simplifier.easy_setup provides a fast path to basic
  5042 Simplifier setup for new object-logics;
  5043 
  5044 * Pure: AST translation rules no longer require constant head on LHS;
  5045 
  5046 * Pure: improved name spaces: ambiguous output is qualified; support
  5047 for hiding of names;
  5048 
  5049 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5050 XSYMBOL_HOME; no longer need to do manual configuration in most
  5051 situations;
  5052 
  5053 * system: compression of ML heaps images may now be controlled via -c
  5054 option of isabelle and isatool usedir (currently only observed by
  5055 Poly/ML);
  5056 
  5057 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5058 useful for remote X11);
  5059 
  5060 * system: provide TAGS file for Isabelle sources;
  5061 
  5062 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5063 order;
  5064 
  5065 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5066 timing flag supersedes proof_timing and Toplevel.trace;
  5067 
  5068 * ML: new combinators |>> and |>>> for incremental transformations
  5069 with secondary results (e.g. certain theory extensions):
  5070 
  5071 * ML: PureThy.add_defs gets additional argument to indicate potential
  5072 overloading (usually false);
  5073 
  5074 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5075 results;
  5076 
  5077 
  5078 
  5079 New in Isabelle99 (October 1999)
  5080 --------------------------------
  5081 
  5082 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5083 
  5084 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5085 are no longer simplified.  (This allows the simplifier to unfold recursive
  5086 functional programs.)  To restore the old behaviour, declare
  5087 
  5088     Delcongs [if_weak_cong];
  5089 
  5090 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5091 complement;
  5092 
  5093 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5094 
  5095 * HOL/datatype: mutual_induct_tac no longer exists --
  5096   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5097 
  5098 * HOL/typedef: fixed type inference for representing set; type
  5099 arguments now have to occur explicitly on the rhs as type constraints;
  5100 
  5101 * ZF: The con_defs part of an inductive definition may no longer refer
  5102 to constants declared in the same theory;
  5103 
  5104 * HOL, ZF: the function mk_cases, generated by the inductive
  5105 definition package, has lost an argument.  To simplify its result, it
  5106 uses the default simpset instead of a supplied list of theorems.
  5107 
  5108 * HOL/List: the constructors of type list are now Nil and Cons;
  5109 
  5110 * Simplifier: the type of the infix ML functions
  5111         setSSolver addSSolver setSolver addSolver
  5112 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5113 for packaging solvers. A solver is created via
  5114         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5115 where the string argument is only a comment.
  5116 
  5117 
  5118 *** Proof tools ***
  5119 
  5120 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5121 decision procedure for linear arithmetic. Currently it is used for
  5122 types `nat', `int', and `real' in HOL (see below); it can, should and
  5123 will be instantiated for other types and logics as well.
  5124 
  5125 * The simplifier now accepts rewrite rules with flexible heads, eg
  5126      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5127   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5128   matching.
  5129 
  5130 
  5131 *** General ***
  5132 
  5133 * New Isabelle/Isar subsystem provides an alternative to traditional
  5134 tactical theorem proving; together with the ProofGeneral/isar user
  5135 interface it offers an interactive environment for developing human
  5136 readable proof documents (Isar == Intelligible semi-automated
  5137 reasoning); for further information see isatool doc isar-ref,
  5138 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5139 
  5140 * improved and simplified presentation of theories: better HTML markup
  5141 (including colors), graph views in several sizes; isatool usedir now
  5142 provides a proper interface for user theories (via -P option); actual
  5143 document preparation based on (PDF)LaTeX is available as well (for
  5144 new-style theories only); see isatool doc system for more information;
  5145 
  5146 * native support for Proof General, both for classic Isabelle and
  5147 Isabelle/Isar;
  5148 
  5149 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5150 using the graph browser tool;
  5151 
  5152 * Isabelle manuals now also available as PDF;
  5153 
  5154 * theory loader rewritten from scratch (may not be fully
  5155 bug-compatible); old loadpath variable has been replaced by show_path,
  5156 add_path, del_path, reset_path functions; new operations such as
  5157 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5158 isatool doc ref);
  5159 
  5160 * improved isatool install: option -k creates KDE application icon,
  5161 option -p DIR installs standalone binaries;
  5162 
  5163 * added ML_PLATFORM setting (useful for cross-platform installations);
  5164 more robust handling of platform specific ML images for SML/NJ;
  5165 
  5166 * the settings environment is now statically scoped, i.e. it is never
  5167 created again in sub-processes invoked from isabelle, isatool, or
  5168 Isabelle;
  5169 
  5170 * path element specification '~~' refers to '$ISABELLE_HOME';
  5171 
  5172 * in locales, the "assumes" and "defines" parts may be omitted if
  5173 empty;
  5174 
  5175 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5176 long arrows);
  5177 
  5178 * new print_mode "HTML";
  5179 
  5180 * new flag show_tags controls display of tags of theorems (which are
  5181 basically just comments that may be attached by some tools);
  5182 
  5183 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5184 mode and goal output format:
  5185 
  5186 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5187 244c244
  5188 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5189 ---
  5190 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5191 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5192 181c181
  5193 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5194 ---
  5195 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5196 
  5197 * function bind_thms stores lists of theorems (cf. bind_thm);
  5198 
  5199 * new shorthand tactics ftac, eatac, datac, fatac;
  5200 
  5201 * qed (and friends) now accept "" as result name; in that case the
  5202 theorem is not stored, but proper checks and presentation of the
  5203 result still apply;
  5204 
  5205 * theorem database now also indexes constants "Trueprop", "all",
  5206 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5207 
  5208 
  5209 *** HOL ***
  5210 
  5211 ** HOL arithmetic **
  5212 
  5213 * There are now decision procedures for linear arithmetic over nat and
  5214 int:
  5215 
  5216 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5217 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5218 are treated as atomic; subformulae not involving type `nat' or `int'
  5219 are ignored; quantified subformulae are ignored unless they are
  5220 positive universal or negative existential. The tactic has to be
  5221 invoked by hand and can be a little bit slow. In particular, the
  5222 running time is exponential in the number of occurrences of `min' and
  5223 `max', and `-' on `nat'.
  5224 
  5225 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5226 (negated) (in)equalities among the premises and the conclusion into
  5227 account (i.e. no compound formulae) and does not know about `min' and
  5228 `max', and `-' on `nat'. It is fast and is used automatically by the
  5229 simplifier.
  5230 
  5231 NB: At the moment, these decision procedures do not cope with mixed
  5232 nat/int formulae where the two parts interact, such as `m < n ==>
  5233 int(m) < int(n)'.
  5234 
  5235 * HOL/Numeral provides a generic theory of numerals (encoded
  5236 efficiently as bit strings); setup for types nat/int/real is in place;
  5237 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5238 int, existing theories and proof scripts may require a few additional
  5239 type constraints;
  5240 
  5241 * integer division and remainder can now be performed on constant
  5242 arguments;
  5243 
  5244 * many properties of integer multiplication, division and remainder
  5245 are now available;
  5246 
  5247 * An interface to the Stanford Validity Checker (SVC) is available through the
  5248 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5249 are proved automatically.  SVC must be installed separately, and its results
  5250 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5251 invocation of the underlying oracle).  For SVC see
  5252   http://verify.stanford.edu/SVC
  5253 
  5254 * IsaMakefile: the HOL-Real target now builds an actual image;
  5255 
  5256 
  5257 ** HOL misc **
  5258 
  5259 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5260 (in Isabelle/Isar) -- by Gertrud Bauer;
  5261 
  5262 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5263 analysis for assembly languages with subtypes;
  5264 
  5265 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5266 -- avoids syntactic ambiguities and treats state, transition, and
  5267 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5268 changed syntax and (many) tactics;
  5269 
  5270 * HOL/inductive: Now also handles more general introduction rules such
  5271   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5272   theorems are now maintained within the theory (maintained via the
  5273   "mono" attribute);
  5274 
  5275 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5276   (using function types) such as
  5277 
  5278   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5279 
  5280 * HOL/record: record_simproc (part of the default simpset) takes care
  5281 of selectors applied to updated records; record_split_tac is no longer
  5282 part of the default claset; update_defs may now be removed from the
  5283 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5284 
  5285   claset_ref () := claset() addSWrapper record_split_wrapper;
  5286   Delsimprocs [record_simproc]
  5287 
  5288 * HOL/typedef: fixed type inference for representing set; type
  5289 arguments now have to occur explicitly on the rhs as type constraints;
  5290 
  5291 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5292 names rather than an ML expression;
  5293 
  5294 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5295 supplied later.  Program schemes can be defined, such as
  5296     "While B C s = (if B s then While B C (C s) else s)"
  5297 where the well-founded relation can be chosen after B and C have been given.
  5298 
  5299 * HOL/List: the constructors of type list are now Nil and Cons;
  5300 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5301 course, ML tools referring to List.list.op # etc. have to be adapted;
  5302 
  5303 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5304 disabled by default; run isabelle with option -m HOL to get back to
  5305 the original Gordon/HOL-style output;
  5306 
  5307 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5308 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5309 
  5310 * HOL basic syntax simplified (more orthogonal): all variants of
  5311 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5312 Eps operator is provided as well: "SOME x. P[x]";
  5313 
  5314 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5315 
  5316 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5317 thus available for user theories;
  5318 
  5319 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5320 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5321 time;
  5322 
  5323 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5324 several times and then mp;
  5325 
  5326 
  5327 *** LK ***
  5328 
  5329 * the notation <<...>> is now available as a notation for sequences of
  5330 formulas;
  5331 
  5332 * the simplifier is now installed
  5333 
  5334 * the axiom system has been generalized (thanks to Soren Heilmann)
  5335 
  5336 * the classical reasoner now has a default rule database
  5337 
  5338 
  5339 *** ZF ***
  5340 
  5341 * new primrec section allows primitive recursive functions to be given
  5342 directly (as in HOL) over datatypes and the natural numbers;
  5343 
  5344 * new tactics induct_tac and exhaust_tac for induction (or case
  5345 analysis) over datatypes and the natural numbers;
  5346 
  5347 * the datatype declaration of type T now defines the recursor T_rec;
  5348 
  5349 * simplification automatically does freeness reasoning for datatype
  5350 constructors;
  5351 
  5352 * automatic type-inference, with AddTCs command to insert new
  5353 type-checking rules;
  5354 
  5355 * datatype introduction rules are now added as Safe Introduction rules
  5356 to the claset;
  5357 
  5358 * the syntax "if P then x else y" is now available in addition to
  5359 if(P,x,y);
  5360 
  5361 
  5362 *** Internal programming interfaces ***
  5363 
  5364 * tuned simplifier trace output; new flag debug_simp;
  5365 
  5366 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5367 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5368 
  5369 * AxClass.axclass_tac lost the theory argument;
  5370 
  5371 * tuned current_goals_markers semantics: begin / end goal avoids
  5372 printing empty lines;
  5373 
  5374 * removed prs and prs_fn hook, which was broken because it did not
  5375 include \n in its semantics, forcing writeln to add one
  5376 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5377 string -> unit if you really want to output text without newline;
  5378 
  5379 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5380 plain output, interface builders may have to enable 'isabelle_font'
  5381 mode to get Isabelle font glyphs as before;
  5382 
  5383 * refined token_translation interface; INCOMPATIBILITY: output length
  5384 now of type real instead of int;
  5385 
  5386 * theory loader actions may be traced via new ThyInfo.add_hook
  5387 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5388 your own database of information attached to *whole* theories -- as
  5389 opposed to intra-theory data slots offered via TheoryDataFun;
  5390 
  5391 * proper handling of dangling sort hypotheses (at last!);
  5392 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5393 extra sort hypotheses that can be witnessed from the type signature;
  5394 the force_strip_shyps flag is gone, any remaining shyps are simply
  5395 left in the theorem (with a warning issued by strip_shyps_warning);
  5396 
  5397 
  5398 
  5399 New in Isabelle98-1 (October 1998)
  5400 ----------------------------------
  5401 
  5402 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5403 
  5404 * several changes of automated proof tools;
  5405 
  5406 * HOL: major changes to the inductive and datatype packages, including
  5407 some minor incompatibilities of theory syntax;
  5408 
  5409 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5410 called `inj_on';
  5411 
  5412 * HOL: removed duplicate thms in Arith:
  5413   less_imp_add_less  should be replaced by  trans_less_add1
  5414   le_imp_add_le      should be replaced by  trans_le_add1
  5415 
  5416 * HOL: unary minus is now overloaded (new type constraints may be
  5417 required);
  5418 
  5419 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5420 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5421 now taken as an integer constant.
  5422 
  5423 * Pure: ML function 'theory_of' renamed to 'theory';
  5424 
  5425 
  5426 *** Proof tools ***
  5427 
  5428 * Simplifier:
  5429   1. Asm_full_simp_tac is now more aggressive.
  5430      1. It will sometimes reorient premises if that increases their power to
  5431         simplify.
  5432      2. It does no longer proceed strictly from left to right but may also
  5433         rotate premises to achieve further simplification.
  5434      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5435      old Asm_full_simp_tac in that it does not rotate premises.
  5436   2. The simplifier now knows a little bit about nat-arithmetic.
  5437 
  5438 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5439 allows for selected deletion of wrappers, by introduction of names for
  5440 wrapper functionals.  This implies that addbefore, addSbefore,
  5441 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5442 and that adding two tactics with the same name overwrites the first
  5443 one (emitting a warning).
  5444   type wrapper = (int -> tactic) -> (int -> tactic)
  5445   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5446   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5447   delWrapper, delSWrapper: claset *  string            -> claset
  5448   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5449 
  5450 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5451 semantics; addbefore now affects only the unsafe part of step_tac
  5452 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5453 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5454 by Force_tac;
  5455 
  5456 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5457 compWrapper; added safe wrapper (and access functions for it);
  5458 
  5459 * HOL/split_all_tac is now much faster and fails if there is nothing
  5460 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5461 and the names of the automatically generated variables have changed.
  5462 split_all_tac has moved within claset() from unsafe wrappers to safe
  5463 wrappers, which means that !!-bound variables are split much more
  5464 aggressively, and safe_tac and clarify_tac now split such variables.
  5465 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5466 Note: the same holds for record_split_tac, which does the job of
  5467 split_all_tac for record fields.
  5468 
  5469 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5470 permanently to the default simpset using Addsplits just like
  5471 Addsimps. They can be removed via Delsplits just like
  5472 Delsimps. Lower-case versions are also available.
  5473 
  5474 * HOL/Simplifier: The rule split_if is now part of the default
  5475 simpset. This means that the simplifier will eliminate all occurrences
  5476 of if-then-else in the conclusion of a goal. To prevent this, you can
  5477 either remove split_if completely from the default simpset by
  5478 `Delsplits [split_if]' or remove it in a specific call of the
  5479 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5480 other case splitting rules to/from the default simpset: every datatype
  5481 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5482 t is the name of the datatype).
  5483 
  5484 * Classical reasoner / Simplifier combination: new force_tac (and
  5485 derivatives Force_tac, force) combines rewriting and classical
  5486 reasoning (and whatever other tools) similarly to auto_tac, but is
  5487 aimed to solve the given subgoal completely.
  5488 
  5489 
  5490 *** General ***
  5491 
  5492 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5493 and `goalw': the theory is no longer needed as an explicit argument -
  5494 the current theory context is used; assumptions are no longer returned
  5495 at the ML-level unless one of them starts with ==> or !!; it is
  5496 recommended to convert to these new commands using isatool fixgoal
  5497 (backup your sources first!);
  5498 
  5499 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5500 the current theory context, and 'theory' to lookup stored theories;
  5501 
  5502 * new theory section 'locale' for declaring constants, assumptions and
  5503 definitions that have local scope;
  5504 
  5505 * new theory section 'nonterminals' for purely syntactic types;
  5506 
  5507 * new theory section 'setup' for generic ML setup functions
  5508 (e.g. package initialization);
  5509 
  5510 * the distribution now includes Isabelle icons: see
  5511 lib/logo/isabelle-{small,tiny}.xpm;
  5512 
  5513 * isatool install - install binaries with absolute references to
  5514 ISABELLE_HOME/bin;
  5515 
  5516 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5517 
  5518 * print mode 'emacs' reserved for Isamode;
  5519 
  5520 * support multiple print (ast) translations per constant name;
  5521 
  5522 * theorems involving oracles are now printed with a suffixed [!];
  5523 
  5524 
  5525 *** HOL ***
  5526 
  5527 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5528 
  5529 * HOL/inductive package reorganized and improved: now supports mutual
  5530 definitions such as
  5531 
  5532   inductive EVEN ODD
  5533     intrs
  5534       null "0 : EVEN"
  5535       oddI "n : EVEN ==> Suc n : ODD"
  5536       evenI "n : ODD ==> Suc n : EVEN"
  5537 
  5538 new theorem list "elims" contains an elimination rule for each of the
  5539 recursive sets; inductive definitions now handle disjunctive premises
  5540 correctly (also ZF);
  5541 
  5542 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5543 "mutual_induct" no longer exists - the induction rule is always
  5544 contained in "induct";
  5545 
  5546 
  5547 * HOL/datatype package re-implemented and greatly improved: now
  5548 supports mutually recursive datatypes such as
  5549 
  5550   datatype
  5551     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5552             | SUM ('a aexp) ('a aexp)
  5553             | DIFF ('a aexp) ('a aexp)
  5554             | NUM 'a
  5555   and
  5556     'a bexp = LESS ('a aexp) ('a aexp)
  5557             | AND ('a bexp) ('a bexp)
  5558             | OR ('a bexp) ('a bexp)
  5559 
  5560 as well as indirectly recursive datatypes such as
  5561 
  5562   datatype
  5563     ('a, 'b) term = Var 'a
  5564                   | App 'b ((('a, 'b) term) list)
  5565 
  5566 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5567 induction on mutually / indirectly recursive datatypes.
  5568 
  5569 Primrec equations are now stored in theory and can be accessed via
  5570 <function_name>.simps.
  5571 
  5572 INCOMPATIBILITIES:
  5573 
  5574   - Theories using datatypes must now have theory Datatype as an
  5575     ancestor.
  5576   - The specific <typename>.induct_tac no longer exists - use the
  5577     generic induct_tac instead.
  5578   - natE has been renamed to nat.exhaust - use exhaust_tac
  5579     instead of res_inst_tac ... natE. Note that the variable
  5580     names in nat.exhaust differ from the names in natE, this
  5581     may cause some "fragile" proofs to fail.
  5582   - The theorems split_<typename>_case and split_<typename>_case_asm
  5583     have been renamed to <typename>.split and <typename>.split_asm.
  5584   - Since default sorts of type variables are now handled correctly,
  5585     some datatype definitions may have to be annotated with explicit
  5586     sort constraints.
  5587   - Primrec definitions no longer require function name and type
  5588     of recursive argument.
  5589 
  5590 Consider using isatool fixdatatype to adapt your theories and proof
  5591 scripts to the new package (backup your sources first!).
  5592 
  5593 
  5594 * HOL/record package: considerably improved implementation; now
  5595 includes concrete syntax for record types, terms, updates; theorems
  5596 for surjective pairing and splitting !!-bound record variables; proof
  5597 support is as follows:
  5598 
  5599   1) standard conversions (selectors or updates applied to record
  5600 constructor terms) are part of the standard simpset;
  5601 
  5602   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5603 made part of standard simpset and claset via addIffs;
  5604 
  5605   3) a tactic for record field splitting (record_split_tac) is part of
  5606 the standard claset (addSWrapper);
  5607 
  5608 To get a better idea about these rules you may retrieve them via
  5609 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5610 the name of your record type.
  5611 
  5612 The split tactic 3) conceptually simplifies by the following rule:
  5613 
  5614   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5615 
  5616 Thus any record variable that is bound by meta-all will automatically
  5617 blow up into some record constructor term, consequently the
  5618 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5619 solve record problems automatically.
  5620 
  5621 
  5622 * reorganized the main HOL image: HOL/Integ and String loaded by
  5623 default; theory Main includes everything;
  5624 
  5625 * automatic simplification of integer sums and comparisons, using cancellation;
  5626 
  5627 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5628 
  5629 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5630 
  5631 * many new identities for unions, intersections, set difference, etc.;
  5632 
  5633 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5634 called split_if, split_split, split_sum_case and split_nat_case (to go
  5635 with add/delsplits);
  5636 
  5637 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5638 (?x::unit) = (); this is made part of the default simpset, which COULD
  5639 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5640 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5641 unit_abs_eta_conv is added in order to counter the effect of
  5642 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5643 %u.f();
  5644 
  5645 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5646 makes more sense);
  5647 
  5648 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5649   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5650   disjointness reasoning but breaking a few old proofs.
  5651 
  5652 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5653 to 'converse' from 'inverse' (for compatibility with ZF and some
  5654 literature);
  5655 
  5656 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5657 the well-founded relation;
  5658 
  5659 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5660     Compl A.  The "Compl" syntax remains available as input syntax for this
  5661     release ONLY.
  5662 
  5663 * HOL/Update: new theory of function updates:
  5664     f(a:=b) == %x. if x=a then b else f x
  5665 may also be iterated as in f(a:=b,c:=d,...);
  5666 
  5667 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5668 
  5669 * HOL/List:
  5670   - new function list_update written xs[i:=v] that updates the i-th
  5671     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5672   - new function `upt' written [i..j(] which generates the list
  5673     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5674     bound write [i..j], which is a shorthand for [i..j+1(].
  5675   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5676 
  5677 * HOL/Arith:
  5678   - removed 'pred' (predecessor) function;
  5679   - generalized some theorems about n-1;
  5680   - many new laws about "div" and "mod";
  5681   - new laws about greatest common divisors (see theory ex/Primes);
  5682 
  5683 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5684 instead of "inverse";
  5685 
  5686 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5687   of the multiset ordering;
  5688 
  5689 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5690   (not included by default);
  5691 
  5692 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5693 
  5694 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5695   programs, i.e. different program variables may have different types.
  5696 
  5697 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5698   [previously, this check worked only if the rewrite rule was unconditional]
  5699   Now rew can involve either definitions or equalities (either == or =).
  5700 
  5701 
  5702 *** ZF ***
  5703 
  5704 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5705   only the theorems proved on ZF.ML;
  5706 
  5707 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5708   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5709   disjointness reasoning but breaking a few old proofs.
  5710 
  5711 * ZF/Update: new theory of function updates
  5712     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5713   may also be iterated as in f(a:=b,c:=d,...);
  5714 
  5715 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5716 
  5717 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5718   [previously, this check worked only if the rewrite rule was unconditional]
  5719   Now rew can involve either definitions or equalities (either == or =).
  5720 
  5721 * case_tac provided for compatibility with HOL
  5722     (like the old excluded_middle_tac, but with subgoals swapped)
  5723 
  5724 
  5725 *** Internal programming interfaces ***
  5726 
  5727 * Pure: several new basic modules made available for general use, see
  5728 also src/Pure/README;
  5729 
  5730 * improved the theory data mechanism to support encapsulation (data
  5731 kind name replaced by private Object.kind, acting as authorization
  5732 key); new type-safe user interface via functor TheoryDataFun; generic
  5733 print_data function becomes basically useless;
  5734 
  5735 * removed global_names compatibility flag -- all theory declarations
  5736 are qualified by default;
  5737 
  5738 * module Pure/Syntax now offers quote / antiquote translation
  5739 functions (useful for Hoare logic etc. with implicit dependencies);
  5740 see HOL/ex/Antiquote for an example use;
  5741 
  5742 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5743 cterm -> thm;
  5744 
  5745 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5746 subgoal;
  5747 
  5748 * Display.print_goals function moved to Locale.print_goals;
  5749 
  5750 * standard print function for goals supports current_goals_markers
  5751 variable for marking begin of proof, end of proof, start of goal; the
  5752 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5753 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5754 for example;
  5755 
  5756 
  5757 
  5758 New in Isabelle98 (January 1998)
  5759 --------------------------------
  5760 
  5761 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5762 
  5763 * changed lexical syntax of terms / types: dots made part of long
  5764 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5765 
  5766 * simpset (and claset) reference variable replaced by functions
  5767 simpset / simpset_ref;
  5768 
  5769 * no longer supports theory aliases (via merge) and non-trivial
  5770 implicit merge of thms' signatures;
  5771 
  5772 * most internal names of constants changed due to qualified names;
  5773 
  5774 * changed Pure/Sequence interface (see Pure/seq.ML);
  5775 
  5776 
  5777 *** General Changes ***
  5778 
  5779 * hierachically structured name spaces (for consts, types, axms, thms
  5780 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5781 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5782 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5783 long_names for fully qualified output names; NOTE: ML programs
  5784 (special tactics, packages etc.) referring to internal names may have
  5785 to be adapted to cope with fully qualified names; in case of severe
  5786 backward campatibility problems try setting 'global_names' at compile
  5787 time to have enrything declared within a flat name space; one may also
  5788 fine tune name declarations in theories via the 'global' and 'local'
  5789 section;
  5790 
  5791 * reimplemented the implicit simpset and claset using the new anytype
  5792 data filed in signatures; references simpset:simpset ref etc. are
  5793 replaced by functions simpset:unit->simpset and
  5794 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5795 to patch your ML files accordingly;
  5796 
  5797 * HTML output now includes theory graph data for display with Java
  5798 applet or isatool browser; data generated automatically via isatool
  5799 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5800 
  5801 * defs may now be conditional; improved rewrite_goals_tac to handle
  5802 conditional equations;
  5803 
  5804 * defs now admits additional type arguments, using TYPE('a) syntax;
  5805 
  5806 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5807 creates a new theory node; implicit merge of thms' signatures is
  5808 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5809 transfer:theory->thm->thm in (rare) cases;
  5810 
  5811 * improved handling of draft signatures / theories; draft thms (and
  5812 ctyps, cterms) are automatically promoted to real ones;
  5813 
  5814 * slightly changed interfaces for oracles: admit many per theory, named
  5815 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5816 
  5817 * print_goals: optional output of const types (set show_consts and
  5818 show_types);
  5819 
  5820 * improved output of warnings (###) and errors (***);
  5821 
  5822 * subgoal_tac displays a warning if the new subgoal has type variables;
  5823 
  5824 * removed old README and Makefiles;
  5825 
  5826 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5827 
  5828 * removed obsolete init_pps and init_database;
  5829 
  5830 * deleted the obsolete tactical STATE, which was declared by
  5831     fun STATE tacfun st = tacfun st st;
  5832 
  5833 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5834 (which abbreviates $HOME);
  5835 
  5836 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5837 use isatool fixseq to adapt your ML programs (this works for fully
  5838 qualified references to the Sequence structure only!);
  5839 
  5840 * use_thy no longer requires writable current directory; it always
  5841 reloads .ML *and* .thy file, if either one is out of date;
  5842 
  5843 
  5844 *** Classical Reasoner ***
  5845 
  5846 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5847 tactics that use classical reasoning to simplify a subgoal without
  5848 splitting it into several subgoals;
  5849 
  5850 * Safe_tac: like safe_tac but uses the default claset;
  5851 
  5852 
  5853 *** Simplifier ***
  5854 
  5855 * added simplification meta rules:
  5856     (asm_)(full_)simplify: simpset -> thm -> thm;
  5857 
  5858 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5859 logics (again);
  5860 
  5861 * added prems argument to simplification procedures;
  5862 
  5863 * HOL, FOL, ZF: added infix function `addsplits':
  5864   instead of `<simpset> setloop (split_tac <thms>)'
  5865   you can simply write `<simpset> addsplits <thms>'
  5866 
  5867 
  5868 *** Syntax ***
  5869 
  5870 * TYPE('a) syntax for type reflection terms;
  5871 
  5872 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5873 
  5874 * pretty printer: changed order of mixfix annotation preference (again!);
  5875 
  5876 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5877 
  5878 
  5879 *** HOL ***
  5880 
  5881 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5882   with `addloop' of the simplifier to faciliate case splitting in premises.
  5883 
  5884 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5885 
  5886 * HOL/Auth: new protocol proofs including some for the Internet
  5887   protocol TLS;
  5888 
  5889 * HOL/Map: new theory of `maps' a la VDM;
  5890 
  5891 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5892 cancelling out common nat summands from =, <, <= (in)equalities, or
  5893 differences; simplification procedures nat_cancel_factor for
  5894 cancelling common factor from =, <, <= (in)equalities over natural
  5895 sums; nat_cancel contains both kinds of procedures, it is installed by
  5896 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5897 
  5898 * HOL/simplifier: terms of the form
  5899   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5900   are rewritten to
  5901   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5902   and those of the form
  5903   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5904   are rewritten to
  5905   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5906 
  5907 * HOL/datatype
  5908   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5909 
  5910   P(t_case f1 ... fn x) =
  5911      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5912         ...
  5913        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5914      )
  5915 
  5916   and a theorem `split_t_case_asm' of the form
  5917 
  5918   P(t_case f1 ... fn x) =
  5919     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5920         ...
  5921        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5922      )
  5923   which can be added to a simpset via `addsplits'. The existing theorems
  5924   expand_list_case and expand_option_case have been renamed to
  5925   split_list_case and split_option_case.
  5926 
  5927 * HOL/Arithmetic:
  5928   - `pred n' is automatically converted to `n-1'.
  5929     Users are strongly encouraged not to use `pred' any longer,
  5930     because it will disappear altogether at some point.
  5931   - Users are strongly encouraged to write "0 < n" rather than
  5932     "n ~= 0". Theorems and proof tools have been modified towards this
  5933     `standard'.
  5934 
  5935 * HOL/Lists:
  5936   the function "set_of_list" has been renamed "set" (and its theorems too);
  5937   the function "nth" now takes its arguments in the reverse order and
  5938   has acquired the infix notation "!" as in "xs!n".
  5939 
  5940 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5941 
  5942 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5943   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5944 
  5945 * HOL/record: extensible records with schematic structural subtyping
  5946 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5947 still lacks various theorems and concrete record syntax;
  5948 
  5949 
  5950 *** HOLCF ***
  5951 
  5952 * removed "axioms" and "generated by" sections;
  5953 
  5954 * replaced "ops" section by extended "consts" section, which is capable of
  5955   handling the continuous function space "->" directly;
  5956 
  5957 * domain package:
  5958   . proves theorems immediately and stores them in the theory,
  5959   . creates hierachical name space,
  5960   . now uses normal mixfix annotations (instead of cinfix...),
  5961   . minor changes to some names and values (for consistency),
  5962   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5963   . separator between mutual domain defs: changed "," to "and",
  5964   . improved handling of sort constraints;  now they have to
  5965     appear on the left-hand side of the equations only;
  5966 
  5967 * fixed LAM <x,y,zs>.b syntax;
  5968 
  5969 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5970 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5971 
  5972 
  5973 *** FOL and ZF ***
  5974 
  5975 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5976   with `addloop' of the simplifier to faciliate case splitting in premises.
  5977 
  5978 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5979 in HOL, they strip ALL and --> from proved theorems;
  5980 
  5981 
  5982 
  5983 New in Isabelle94-8 (May 1997)
  5984 ------------------------------
  5985 
  5986 *** General Changes ***
  5987 
  5988 * new utilities to build / run / maintain Isabelle etc. (in parts
  5989 still somewhat experimental); old Makefiles etc. still functional;
  5990 
  5991 * new 'Isabelle System Manual';
  5992 
  5993 * INSTALL text, together with ./configure and ./build scripts;
  5994 
  5995 * reimplemented type inference for greater efficiency, better error
  5996 messages and clean internal interface;
  5997 
  5998 * prlim command for dealing with lots of subgoals (an easier way of
  5999 setting goals_limit);
  6000 
  6001 
  6002 *** Syntax ***
  6003 
  6004 * supports alternative (named) syntax tables (parser and pretty
  6005 printer); internal interface is provided by add_modesyntax(_i);
  6006 
  6007 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6008 be used in conjunction with the Isabelle symbol font; uses the
  6009 "symbols" syntax table;
  6010 
  6011 * added token_translation interface (may translate name tokens in
  6012 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6013 the current print_mode); IMPORTANT: user print translation functions
  6014 are responsible for marking newly introduced bounds
  6015 (Syntax.mark_boundT);
  6016 
  6017 * token translations for modes "xterm" and "xterm_color" that display
  6018 names in bold, underline etc. or colors (which requires a color
  6019 version of xterm);
  6020 
  6021 * infixes may now be declared with names independent of their syntax;
  6022 
  6023 * added typed_print_translation (like print_translation, but may
  6024 access type of constant);
  6025 
  6026 
  6027 *** Classical Reasoner ***
  6028 
  6029 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6030 some limitations.  Blast_tac...
  6031   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6032   + ignores elimination rules that don't have the correct format
  6033         (the conclusion MUST be a formula variable)
  6034   + ignores types, which can make HOL proofs fail
  6035   + rules must not require higher-order unification, e.g. apply_type in ZF
  6036     [message "Function Var's argument not a bound variable" relates to this]
  6037   + its proof strategy is more general but can actually be slower
  6038 
  6039 * substitution with equality assumptions no longer permutes other
  6040 assumptions;
  6041 
  6042 * minor changes in semantics of addafter (now called addaltern); renamed
  6043 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6044 (and access functions for it);
  6045 
  6046 * improved combination of classical reasoner and simplifier:
  6047   + functions for handling clasimpsets
  6048   + improvement of addss: now the simplifier is called _after_ the
  6049     safe steps.
  6050   + safe variant of addss called addSss: uses safe simplifications
  6051     _during_ the safe steps. It is more complete as it allows multiple
  6052     instantiations of unknowns (e.g. with slow_tac).
  6053 
  6054 *** Simplifier ***
  6055 
  6056 * added interface for simplification procedures (functions that
  6057 produce *proven* rewrite rules on the fly, depending on current
  6058 redex);
  6059 
  6060 * ordering on terms as parameter (used for ordered rewriting);
  6061 
  6062 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6063 
  6064 * the solver is now split into a safe and an unsafe part.
  6065 This should be invisible for the normal user, except that the
  6066 functions setsolver and addsolver have been renamed to setSolver and
  6067 addSolver; added safe_asm_full_simp_tac;
  6068 
  6069 
  6070 *** HOL ***
  6071 
  6072 * a generic induction tactic `induct_tac' which works for all datatypes and
  6073 also for type `nat';
  6074 
  6075 * a generic case distinction tactic `exhaust_tac' which works for all
  6076 datatypes and also for type `nat';
  6077 
  6078 * each datatype comes with a function `size';
  6079 
  6080 * patterns in case expressions allow tuple patterns as arguments to
  6081 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6082 
  6083 * primrec now also works with type nat;
  6084 
  6085 * recdef: a new declaration form, allows general recursive functions to be
  6086 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6087 
  6088 * the constant for negation has been renamed from "not" to "Not" to
  6089 harmonize with FOL, ZF, LK, etc.;
  6090 
  6091 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6092 infinite lists;
  6093 
  6094 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6095 
  6096 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6097 problems in commutative rings, using axiomatic type classes for + and *;
  6098 
  6099 * more examples in HOL/MiniML and HOL/Auth;
  6100 
  6101 * more default rewrite rules for quantifiers, union/intersection;
  6102 
  6103 * a new constant `arbitrary == @x.False';
  6104 
  6105 * HOLCF/IOA replaces old HOL/IOA;
  6106 
  6107 * HOLCF changes: derived all rules and arities
  6108   + axiomatic type classes instead of classes
  6109   + typedef instead of faking type definitions
  6110   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6111   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6112   + eliminated the types void, one, tr
  6113   + use unit lift and bool lift (with translations) instead of one and tr
  6114   + eliminated blift from Lift3.thy (use Def instead of blift)
  6115   all eliminated rules are derived as theorems --> no visible changes ;
  6116 
  6117 
  6118 *** ZF ***
  6119 
  6120 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6121 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6122 as ZF_cs addSIs [equalityI];
  6123 
  6124 
  6125 
  6126 New in Isabelle94-7 (November 96)
  6127 ---------------------------------
  6128 
  6129 * allowing negative levels (as offsets) in prlev and choplev;
  6130 
  6131 * super-linear speedup for large simplifications;
  6132 
  6133 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6134 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6135 FAIL); can suppress it using the command Delsimps (ex_simps @
  6136 all_simps); De Morgan laws are also now included, by default;
  6137 
  6138 * improved printing of ==>  :  ~:
  6139 
  6140 * new object-logic "Sequents" adds linear logic, while replacing LK
  6141 and Modal (thanks to Sara Kalvala);
  6142 
  6143 * HOL/Auth: correctness proofs for authentication protocols;
  6144 
  6145 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6146 examples on HOL/Auth);
  6147 
  6148 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6149 the rewriter and classical reasoner simultaneously;
  6150 
  6151 * function uresult no longer returns theorems in "standard" format;
  6152 regain previous version by: val uresult = standard o uresult;
  6153 
  6154 
  6155 
  6156 New in Isabelle94-6
  6157 -------------------
  6158 
  6159 * oracles -- these establish an interface between Isabelle and trusted
  6160 external reasoners, which may deliver results as theorems;
  6161 
  6162 * proof objects (in particular record all uses of oracles);
  6163 
  6164 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6165 
  6166 * "constdefs" section in theory files;
  6167 
  6168 * "primrec" section (HOL) no longer requires names;
  6169 
  6170 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6171 
  6172 
  6173 
  6174 New in Isabelle94-5
  6175 -------------------
  6176 
  6177 * reduced space requirements;
  6178 
  6179 * automatic HTML generation from theories;
  6180 
  6181 * theory files no longer require "..." (quotes) around most types;
  6182 
  6183 * new examples, including two proofs of the Church-Rosser theorem;
  6184 
  6185 * non-curried (1994) version of HOL is no longer distributed;
  6186 
  6187 
  6188 
  6189 New in Isabelle94-4
  6190 -------------------
  6191 
  6192 * greatly reduced space requirements;
  6193 
  6194 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6195 
  6196 * searchable theorem database (see the section "Retrieving theorems" on
  6197 page 8 of the Reference Manual);
  6198 
  6199 * new examples, including Grabczewski's monumental case study of the
  6200 Axiom of Choice;
  6201 
  6202 * The previous version of HOL renamed to Old_HOL;
  6203 
  6204 * The new version of HOL (previously called CHOL) uses a curried syntax
  6205 for functions.  Application looks like f a b instead of f(a,b);
  6206 
  6207 * Mutually recursive inductive definitions finally work in HOL;
  6208 
  6209 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6210 translates to the operator "split";
  6211 
  6212 
  6213 
  6214 New in Isabelle94-3
  6215 -------------------
  6216 
  6217 * new infix operator, addss, allowing the classical reasoner to
  6218 perform simplification at each step of its search.  Example:
  6219         fast_tac (cs addss ss)
  6220 
  6221 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6222 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6223 look like (a,b) instead of <a,b>;
  6224 
  6225 * PLEASE NOTE: CHOL will eventually replace HOL!
  6226 
  6227 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6228 It translates to the operator "split".  A new theory of integers is available;
  6229 
  6230 * In ZF, integer numerals now denote two's-complement binary integers.
  6231 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6232 
  6233 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6234 of the Axiom of Choice;
  6235 
  6236 
  6237 
  6238 New in Isabelle94-2
  6239 -------------------
  6240 
  6241 * Significantly faster resolution;
  6242 
  6243 * the different sections in a .thy file can now be mixed and repeated
  6244 freely;
  6245 
  6246 * Database of theorems for FOL, HOL and ZF.  New
  6247 commands including qed, qed_goal and bind_thm store theorems in the database.
  6248 
  6249 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6250 a given theory (thms_of), or find out what theory a theorem was proved in
  6251 (theory_of_thm);
  6252 
  6253 * Bugs fixed in the inductive definition and datatype packages;
  6254 
  6255 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6256 and HOL_dup_cs obsolete;
  6257 
  6258 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6259 have been removed;
  6260 
  6261 * Simpler definition of function space in ZF;