NEWS
author wenzelm
Thu Apr 02 14:09:41 2009 +0200 (2009-04-02)
changeset 30849 0e5ec6d2c1d9
parent 30847 dd9a1662413b
child 30855 c22436e6d350
permissions -rw-r--r--
some 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 * Modernized versions of commands 'nominal_inductive',
   617 'nominal_primrec', and 'equivariance' work with local theory targets.
   618 
   619 
   620 *** HOLCF ***
   621 
   622 * Reimplemented the simplification procedure for proving continuity
   623 subgoals.  The new simproc is extensible; users can declare additional
   624 continuity introduction rules with the attribute [cont2cont].
   625 
   626 * The continuity simproc now uses a different introduction rule for
   627 solving continuity subgoals on terms with lambda abstractions.  In
   628 some rare cases the new simproc may fail to solve subgoals that the
   629 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   630 Potential INCOMPATIBILITY.
   631 
   632 * Command 'fixrec': specification syntax now conforms to the general
   633 format as seen in 'inductive', 'primrec', 'function', etc.  See
   634 src/HOLCF/ex/Fixrec_ex.thy for examples.  INCOMPATIBILITY.
   635 
   636 
   637 *** ZF ***
   638 
   639 * Proof of Zorn's Lemma for partial orders.
   640 
   641 
   642 *** ML ***
   643 
   644 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   645 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   646 depends on multithreading, so timouts will not work before Poly/ML
   647 5.2.1!
   648 
   649 * High-level support for concurrent ML programming, see
   650 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   651 particularly convenient to organize independent functional
   652 computations.  The concept of "synchronized variables" provides a
   653 higher-order interface for components with shared state, avoiding the
   654 delicate details of mutexes and condition variables.  (Requires
   655 Poly/ML 5.2.1 or later.)
   656 
   657 * ML bindings produced via Isar commands are stored within the Isar
   658 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   659 become thread-safe and work with undo as expected (concerning
   660 top-level bindings, not side-effects on global references).
   661 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   662 compiler at runtime; really global bindings need to be given outside a
   663 theory.  (Requires Poly/ML 5.2 or later.)
   664 
   665 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   666 context.  Top-level ML bindings are stored within the proof context in
   667 a purely sequential fashion, disregarding the nested proof structure.
   668 ML bindings introduced by 'ML_prf' are discarded at the end of the
   669 proof.  (Requires Poly/ML 5.2 or later.)
   670 
   671 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   672 and Method.setup, as well as Isar commands 'attribute_setup' and
   673 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   674 existing code accordingly, or use plain 'setup' together with old
   675 Method.add_method.
   676 
   677 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   678 to 'a -> thm, while results are always tagged with an authentic oracle
   679 name.  The Isar command 'oracle' is now polymorphic, no argument type
   680 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   681 accordingly.  Note that extra performance may be gained by producing
   682 the cterm carefully, avoiding slow Thm.cterm_of.
   683 
   684 * Simplified interface for defining document antiquotations via
   685 ThyOutput.antiquotation, ThyOutput.output, and optionally
   686 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   687 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   688 examples.
   689 
   690 * More systematic treatment of long names, abstract name bindings, and
   691 name space operations.  Basic operations on qualified names have been
   692 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   693 Long_Name.append.  Old type bstring has been mostly replaced by
   694 abstract type binding (see structure Binding), which supports precise
   695 qualification by packages and local theory targets, as well as proper
   696 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   697 bstring values into Binding.name, or better pass through abstract
   698 bindings everywhere.  See further src/Pure/General/long_name.ML,
   699 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   700 
   701 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   702 LocalTheory.note etc.) now refer to the *full* internal name, not the
   703 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   704 
   705 * Disposed old type and term read functions (Sign.read_def_typ,
   706 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   707 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   708 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   709 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   710 resort for legacy applications.
   711 
   712 * Disposed old declarations, tactics, tactic combinators that refer to
   713 the simpset or claset of an implicit theory (such as Addsimps,
   714 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   715 embedded ML text, or local_simpset_of with a proper context passed as
   716 explicit runtime argument.
   717 
   718 * Rules and tactics that read instantiations (read_instantiate,
   719 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   720 context, which is required for parsing and type-checking.  Moreover,
   721 the variables are specified as plain indexnames, not string encodings
   722 thereof.  INCOMPATIBILITY.
   723 
   724 * Generic Toplevel.add_hook interface allows to analyze the result of
   725 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   726 for theorem dependency output of transactions resulting in a new
   727 theory state.
   728 
   729 * ML antiquotations: block-structured compilation context indicated by
   730 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   731 
   732   @{binding name}                         - basic name binding
   733   @{let ?pat = term}                      - term abbreviation (HO matching)
   734   @{note name = fact}                     - fact abbreviation
   735   @{thm fact}                             - singleton fact (with attributes)
   736   @{thms fact}                            - general fact (with attributes)
   737   @{lemma prop by method}                 - singleton goal
   738   @{lemma prop by meth1 meth2}            - singleton goal
   739   @{lemma prop1 ... propN by method}      - general goal
   740   @{lemma prop1 ... propN by meth1 meth2} - general goal
   741   @{lemma (open) ...}                     - open derivation
   742 
   743 
   744 *** System ***
   745 
   746 * The Isabelle "emacs" tool provides a specific interface to invoke
   747 Proof General / Emacs, with more explicit failure if that is not
   748 installed (the old isabelle-interface script silently falls back on
   749 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   750 installation location of the Proof General distribution.
   751 
   752 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   753 the Isabelle process into a JVM/Scala application.  See
   754 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   755 process wrapper has been discontinued.)
   756 
   757 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   758 
   759 * Various status messages (with exact source position information) are
   760 emitted, if proper markup print mode is enabled.  This allows
   761 user-interface components to provide detailed feedback on internal
   762 prover operations.
   763 
   764 
   765 
   766 New in Isabelle2008 (June 2008)
   767 -------------------------------
   768 
   769 *** General ***
   770 
   771 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   772 and updated, with formally checked references as hyperlinks.
   773 
   774 * Theory loader: use_thy (and similar operations) no longer set the
   775 implicit ML context, which was occasionally hard to predict and in
   776 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   777 provides a proper context already.
   778 
   779 * Theory loader: old-style ML proof scripts being *attached* to a thy
   780 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   781 'use' within a theory file will do the job.
   782 
   783 * Name space merge now observes canonical order, i.e. the second space
   784 is inserted into the first one, while existing entries in the first
   785 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   786 swap theory imports.
   787 
   788 * Syntax: symbol \<chi> is now considered a letter.  Potential
   789 INCOMPATIBILITY in identifier syntax etc.
   790 
   791 * Outer syntax: string tokens no longer admit escaped white space,
   792 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   793 white space without escapes.
   794 
   795 * Outer syntax: string tokens may contain arbitrary character codes
   796 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   797 "foo_bar".
   798 
   799 
   800 *** Pure ***
   801 
   802 * Context-dependent token translations.  Default setup reverts locally
   803 fixed variables, and adds hilite markup for undeclared frees.
   804 
   805 * Unused theorems can be found using the new command 'unused_thms'.
   806 There are three ways of invoking it:
   807 
   808 (1) unused_thms
   809      Only finds unused theorems in the current theory.
   810 
   811 (2) unused_thms thy_1 ... thy_n -
   812      Finds unused theorems in the current theory and all of its ancestors,
   813      excluding the theories thy_1 ... thy_n and all of their ancestors.
   814 
   815 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   816      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   817      their ancestors, excluding the theories thy_1 ... thy_n and all of
   818      their ancestors.
   819 
   820 In order to increase the readability of the list produced by
   821 unused_thms, theorems that have been created by a particular instance
   822 of a theory command such as 'inductive' or 'function' are considered
   823 to belong to the same "group", meaning that if at least one theorem in
   824 this group is used, the other theorems in the same group are no longer
   825 reported as unused.  Moreover, if all theorems in the group are
   826 unused, only one theorem in the group is displayed.
   827 
   828 Note that proof objects have to be switched on in order for
   829 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   830 usually the case when using Proof General with the default settings).
   831 
   832 * Authentic naming of facts disallows ad-hoc overwriting of previous
   833 theorems within the same name space.  INCOMPATIBILITY, need to remove
   834 duplicate fact bindings, or even accidental fact duplications.  Note
   835 that tools may maintain dynamically scoped facts systematically, using
   836 PureThy.add_thms_dynamic.
   837 
   838 * Command 'hide' now allows to hide from "fact" name space as well.
   839 
   840 * Eliminated destructive theorem database, simpset, claset, and
   841 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   842 update of theories within ML code.
   843 
   844 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   845 INCOMPATIBILITY, object-logics depending on former Pure require
   846 additional setup PureThy.old_appl_syntax_setup; object-logics
   847 depending on former CPure need to refer to Pure.
   848 
   849 * Commands 'use' and 'ML' are now purely functional, operating on
   850 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   851 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   852 INCOMPATIBILITY.
   853 
   854 * Command 'setup': discontinued implicit version with ML reference.
   855 
   856 * Instantiation target allows for simultaneous specification of class
   857 instance operations together with an instantiation proof.
   858 Type-checking phase allows to refer to class operations uniformly.
   859 See src/HOL/Complex/Complex.thy for an Isar example and
   860 src/HOL/Library/Eval.thy for an ML example.
   861 
   862 * Indexing of literal facts: be more serious about including only
   863 facts from the visible specification/proof context, but not the
   864 background context (locale etc.).  Affects `prop` notation and method
   865 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   866 situations.
   867 
   868 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   869 "(open)" option, which used to expose internal bound variables to the
   870 proof text.
   871 
   872 * Isar statements: removed obsolete case "rule_context".
   873 INCOMPATIBILITY, better use explicit fixes/assumes.
   874 
   875 * Locale proofs: default proof step now includes 'unfold_locales';
   876 hence 'proof' without argument may be used to unfold locale
   877 predicates.
   878 
   879 
   880 *** Document preparation ***
   881 
   882 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   883 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   884 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   885 spot); renamed link color from "darkblue" to "linkcolor" (default
   886 value unchanged, can be redefined via \definecolor); no longer sets
   887 "a4paper" option (unnecessary or even intrusive).
   888 
   889 * Antiquotation @{lemma A method} proves proposition A by the given
   890 method (either a method name or a method name plus (optional) method
   891 arguments in parentheses) and prints A just like @{prop A}.
   892 
   893 
   894 *** HOL ***
   895 
   896 * New primrec package.  Specification syntax conforms in style to
   897 definition/function/....  No separate induction rule is provided.  The
   898 "primrec" command distinguishes old-style and new-style specifications
   899 by syntax.  The former primrec package is now named OldPrimrecPackage.
   900 When adjusting theories, beware: constants stemming from new-style
   901 primrec specifications have authentic syntax.
   902 
   903 * Metis prover is now an order of magnitude faster, and also works
   904 with multithreading.
   905 
   906 * Metis: the maximum number of clauses that can be produced from a
   907 theorem is now given by the attribute max_clauses.  Theorems that
   908 exceed this number are ignored, with a warning printed.
   909 
   910 * Sledgehammer no longer produces structured proofs by default. To
   911 enable, declare [[sledgehammer_full = true]].  Attributes
   912 reconstruction_modulus, reconstruction_sorts renamed
   913 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   914 
   915 * Method "induct_scheme" derives user-specified induction rules
   916 from well-founded induction and completeness of patterns. This factors
   917 out some operations that are done internally by the function package
   918 and makes them available separately.  See
   919 src/HOL/ex/Induction_Scheme.thy for examples.
   920 
   921 * More flexible generation of measure functions for termination
   922 proofs: Measure functions can be declared by proving a rule of the
   923 form "is_measure f" and giving it the [measure_function] attribute.
   924 The "is_measure" predicate is logically meaningless (always true), and
   925 just guides the heuristic.  To find suitable measure functions, the
   926 termination prover sets up the goal "is_measure ?f" of the appropriate
   927 type and generates all solutions by prolog-style backwards proof using
   928 the declared rules.
   929 
   930 This setup also deals with rules like 
   931 
   932   "is_measure f ==> is_measure (list_size f)"
   933 
   934 which accommodates nested datatypes that recurse through lists.
   935 Similar rules are predeclared for products and option types.
   936 
   937 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   938 
   939   INCOMPATIBILITIES:
   940 
   941   - Definitions of overloaded constants on sets have to be replaced by
   942     definitions on => and bool.
   943 
   944   - Some definitions of overloaded operators on sets can now be proved
   945     using the definitions of the operators on => and bool.  Therefore,
   946     the following theorems have been renamed:
   947 
   948       subset_def   -> subset_eq
   949       psubset_def  -> psubset_eq
   950       set_diff_def -> set_diff_eq
   951       Compl_def    -> Compl_eq
   952       Sup_set_def  -> Sup_set_eq
   953       Inf_set_def  -> Inf_set_eq
   954       sup_set_def  -> sup_set_eq
   955       inf_set_def  -> inf_set_eq
   956 
   957   - Due to the incompleteness of the HO unification algorithm, some
   958     rules such as subst may require manual instantiation, if some of
   959     the unknowns in the rule is a set.
   960 
   961   - Higher order unification and forward proofs:
   962     The proof pattern
   963 
   964       have "P (S::'a set)" <...>
   965       then have "EX S. P S" ..
   966 
   967     no longer works (due to the incompleteness of the HO unification
   968     algorithm) and must be replaced by the pattern
   969 
   970       have "EX S. P S"
   971       proof
   972         show "P S" <...>
   973       qed
   974 
   975   - Calculational reasoning with subst (or similar rules):
   976     The proof pattern
   977 
   978       have "P (S::'a set)" <...>
   979       also have "S = T" <...>
   980       finally have "P T" .
   981 
   982     no longer works (for similar reasons as the previous example) and
   983     must be replaced by something like
   984 
   985       have "P (S::'a set)" <...>
   986       moreover have "S = T" <...>
   987       ultimately have "P T" by simp
   988 
   989   - Tactics or packages written in ML code:
   990     Code performing pattern matching on types via
   991 
   992       Type ("set", [T]) => ...
   993 
   994     must be rewritten. Moreover, functions like strip_type or
   995     binder_types no longer return the right value when applied to a
   996     type of the form
   997 
   998       T1 => ... => Tn => U => bool
   999 
  1000     rather than
  1001 
  1002       T1 => ... => Tn => U set
  1003 
  1004 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1005 Wellfounded_Relations to theory Wellfounded.
  1006 
  1007 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1008 
  1009 * Class finite no longer treats UNIV as class parameter.  Use class
  1010 enum from theory Library/Enum instead to achieve a similar effect.
  1011 INCOMPATIBILITY.
  1012 
  1013 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1014 and "Cons".  INCOMPATIBILITY.
  1015 
  1016 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1017 Potential INCOMPATIBILITY.
  1018 
  1019 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1020 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1021 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1022 
  1023 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1024 the same name in theory Orderings:
  1025 
  1026   less_trans
  1027   less_linear
  1028   le_imp_less_or_eq
  1029   le_less_trans
  1030   less_le_trans
  1031   less_not_sym
  1032   less_asym
  1033 
  1034 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1035 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1036 and different variable names.
  1037 
  1038 * Library/Option_ord.thy: Canonical order on option type.
  1039 
  1040 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1041 finite maps.
  1042 
  1043 * Library/Countable.thy: Type class for countable types.
  1044 
  1045 * Theory Int: The representation of numerals has changed.  The infix
  1046 operator BIT and the bit datatype with constructors B0 and B1 have
  1047 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1048 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1049 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1050 accordingly.
  1051 
  1052 * Theory Nat: definition of <= and < on natural numbers no longer
  1053 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1054 le_def and less_def have disappeared.  Consider lemmas not_less
  1055 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1056 
  1057 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1058 (whose purpose mainly is for various fold_set functionals) have been
  1059 abandoned in favor of the existing algebraic classes
  1060 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1061 lower_semilattice (resp. upper_semilattice) and linorder.
  1062 INCOMPATIBILITY.
  1063 
  1064 * Theory Transitive_Closure: induct and cases rules now declare proper
  1065 case_names ("base" and "step").  INCOMPATIBILITY.
  1066 
  1067 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1068 lattices.  The form set-specific version is available as
  1069 Inductive.lfp_ordinal_induct_set.
  1070 
  1071 * Renamed theorems "power.simps" to "power_int.simps".
  1072 INCOMPATIBILITY.
  1073 
  1074 * Class semiring_div provides basic abstract properties of semirings
  1075 with division and modulo operations.  Subsumes former class dvd_mod.
  1076 
  1077 * Merged theories IntDef, Numeral and IntArith into unified theory
  1078 Int.  INCOMPATIBILITY.
  1079 
  1080 * Theory Library/Code_Index: type "index" now represents natural
  1081 numbers rather than integers.  INCOMPATIBILITY.
  1082 
  1083 * New class "uminus" with operation "uminus" (split of from class
  1084 "minus" which now only has operation "minus", binary).
  1085 INCOMPATIBILITY.
  1086 
  1087 * Constants "card", "internal_split", "option_map" now with authentic
  1088 syntax.  INCOMPATIBILITY.
  1089 
  1090 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1091 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1092 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1093 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1094 Sup_set_def, le_def, less_def, option_map_def now with object
  1095 equality.  INCOMPATIBILITY.
  1096 
  1097 * Records. Removed K_record, and replaced it by pure lambda term
  1098 %x. c. The simplifier setup is now more robust against eta expansion.
  1099 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1100 
  1101 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1102 
  1103 * Library/ListVector: new theory of arithmetic vector operations.
  1104 
  1105 * Library/Order_Relation: new theory of various orderings as sets of
  1106 pairs.  Defines preorders, partial orders, linear orders and
  1107 well-orders on sets and on types.
  1108 
  1109 
  1110 *** ZF ***
  1111 
  1112 * Renamed some theories to allow to loading both ZF and HOL in the
  1113 same session:
  1114 
  1115   Datatype  -> Datatype_ZF
  1116   Inductive -> Inductive_ZF
  1117   Int       -> Int_ZF
  1118   IntDiv    -> IntDiv_ZF
  1119   Nat       -> Nat_ZF
  1120   List      -> List_ZF
  1121   Main      -> Main_ZF
  1122 
  1123 INCOMPATIBILITY: ZF theories that import individual theories below
  1124 Main might need to be adapted.  Regular theory Main is still
  1125 available, as trivial extension of Main_ZF.
  1126 
  1127 
  1128 *** ML ***
  1129 
  1130 * ML within Isar: antiquotation @{const name} or @{const
  1131 name(typargs)} produces statically-checked Const term.
  1132 
  1133 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1134 (of the same name).  Removed obsolete print command.
  1135 
  1136 * Removed obsolete "use_legacy_bindings" function.
  1137 
  1138 * The ``print mode'' is now a thread-local value derived from a global
  1139 template (the former print_mode reference), thus access becomes
  1140 non-critical.  The global print_mode reference is for session
  1141 management only; user-code should use print_mode_value,
  1142 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1143 
  1144 * Functions system/system_out provide a robust way to invoke external
  1145 shell commands, with propagation of interrupts (requires Poly/ML
  1146 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1147 
  1148 
  1149 *** System ***
  1150 
  1151 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1152 in accordance with Proof General 3.7, which prefers GNU emacs.
  1153 
  1154 * isatool tty runs Isabelle process with plain tty interaction;
  1155 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1156 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1157 
  1158 * isatool browser now works with Cygwin as well, using general
  1159 "javapath" function defined in Isabelle process environment.
  1160 
  1161 * YXML notation provides a simple and efficient alternative to
  1162 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1163 isatool yxml as described in the Isabelle system manual.
  1164 
  1165 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1166 provides general wrapper for managing an Isabelle process in a robust
  1167 fashion, with ``cooked'' output from stdin/stderr.
  1168 
  1169 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1170 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1171 
  1172 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1173 way of changing the user's settings is via
  1174 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1175 script.
  1176 
  1177 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1178 cores of the underlying machine, which is a good starting point for
  1179 optimal performance tuning.  The corresponding usedir option -M allows
  1180 "max" as an alias for "0".  WARNING: does not work on certain versions
  1181 of Mac OS (with Poly/ML 5.1).
  1182 
  1183 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1184 adverse effect of Isabelle flooding interactive front-ends (notably
  1185 ProofGeneral / XEmacs).
  1186 
  1187 
  1188 
  1189 New in Isabelle2007 (November 2007)
  1190 -----------------------------------
  1191 
  1192 *** General ***
  1193 
  1194 * More uniform information about legacy features, notably a
  1195 warning/error of "Legacy feature: ...", depending on the state of the
  1196 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1197 legacy features will disappear eventually.
  1198 
  1199 * Theory syntax: the header format ``theory A = B + C:'' has been
  1200 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1201 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1202 
  1203 * Theory syntax: the old non-Isar theory file format has been
  1204 discontinued altogether.  Note that ML proof scripts may still be used
  1205 with Isar theories; migration is usually quite simple with the ML
  1206 function use_legacy_bindings.  INCOMPATIBILITY.
  1207 
  1208 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1209 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1210 quotes.
  1211 
  1212 * Theory loader: be more serious about observing the static theory
  1213 header specifications (including optional directories), but not the
  1214 accidental file locations of previously successful loads.  The strict
  1215 update policy of former update_thy is now already performed by
  1216 use_thy, so the former has been removed; use_thys updates several
  1217 theories simultaneously, just as 'imports' within a theory header
  1218 specification, but without merging the results.  Potential
  1219 INCOMPATIBILITY: may need to refine theory headers and commands
  1220 ROOT.ML which depend on load order.
  1221 
  1222 * Theory loader: optional support for content-based file
  1223 identification, instead of the traditional scheme of full physical
  1224 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1225 (cf. the system manual).  The new scheme allows to work with
  1226 non-finished theories in persistent session images, such that source
  1227 files may be moved later on without requiring reloads.
  1228 
  1229 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1230 file (with the same base name as the theory) are considered a legacy
  1231 feature, which will disappear eventually. Even now, the theory loader
  1232 no longer maintains dependencies on such files.
  1233 
  1234 * Syntax: the scope for resolving ambiguities via type-inference is
  1235 now limited to individual terms, instead of whole simultaneous
  1236 specifications as before. This greatly reduces the complexity of the
  1237 syntax module and improves flexibility by separating parsing and
  1238 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1239 'fixes' etc.) are required in rare situations.
  1240 
  1241 * Syntax: constants introduced by new-style packages ('definition',
  1242 'abbreviation' etc.) are passed through the syntax module in
  1243 ``authentic mode''. This means that associated mixfix annotations
  1244 really stick to such constants, independently of potential name space
  1245 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1246 trees are represented slightly differently, may need to adapt syntax
  1247 translations accordingly. Use CONST marker in 'translations' and
  1248 @{const_syntax} antiquotation in 'parse_translation' etc.
  1249 
  1250 * Legacy goal package: reduced interface to the bare minimum required
  1251 to keep existing proof scripts running.  Most other user-level
  1252 functions are now part of the OldGoals structure, which is *not* open
  1253 by default (consider isatool expandshort before open OldGoals).
  1254 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1255 these tend to cause confusion about the actual goal (!) context being
  1256 used here, which is not necessarily the same as the_context().
  1257 
  1258 * Command 'find_theorems': supports "*" wild-card in "name:"
  1259 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1260 support a specific search form (see ProofGeneral/CHANGES).
  1261 
  1262 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1263 by default, which means that "prems" (and also "fixed variables") are
  1264 suppressed from proof state output.  Note that the ProofGeneral
  1265 settings mechanism allows to change and save options persistently, but
  1266 older versions of Isabelle will fail to start up if a negative prems
  1267 limit is imposed.
  1268 
  1269 * Local theory targets may be specified by non-nested blocks of
  1270 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1271 contain definitions, theorems etc., including any derived mechanism
  1272 that has been implemented on top of these primitives.  This concept
  1273 generalizes the existing ``theorem (in ...)'' towards more versatility
  1274 and scalability.
  1275 
  1276 * Proof General interface: proper undo of final 'end' command;
  1277 discontinued Isabelle/classic mode (ML proof scripts).
  1278 
  1279 
  1280 *** Document preparation ***
  1281 
  1282 * Added antiquotation @{theory name} which prints the given name,
  1283 after checking that it refers to a valid ancestor theory in the
  1284 current context.
  1285 
  1286 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1287 check the given source text as ML type/structure, printing verbatim.
  1288 
  1289 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1290 "c args == rhs" given in the current context.  (Any number of
  1291 arguments may be given on the LHS.)
  1292 
  1293 
  1294 *** Pure ***
  1295 
  1296 * The 'class' package offers a combination of axclass and locale to
  1297 achieve Haskell-like type classes in Isabelle.  Definitions and
  1298 theorems within a class context produce both relative results (with
  1299 implicit parameters according to the locale context), and polymorphic
  1300 constants with qualified polymorphism (according to the class
  1301 context).  Within the body context of a 'class' target, a separate
  1302 syntax layer ("user space type system") takes care of converting
  1303 between global polymorphic consts and internal locale representation.
  1304 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1305 "isatool doc classes" provides a tutorial.
  1306 
  1307 * Generic code generator framework allows to generate executable
  1308 code for ML and Haskell (including Isabelle classes).  A short usage
  1309 sketch:
  1310 
  1311     internal compilation:
  1312         export_code <list of constants (term syntax)> in SML
  1313     writing SML code to a file:
  1314         export_code <list of constants (term syntax)> in SML <filename>
  1315     writing OCaml code to a file:
  1316         export_code <list of constants (term syntax)> in OCaml <filename>
  1317     writing Haskell code to a bunch of files:
  1318         export_code <list of constants (term syntax)> in Haskell <filename>
  1319 
  1320     evaluating closed propositions to True/False using code generation:
  1321         method ``eval''
  1322 
  1323 Reasonable default setup of framework in HOL.
  1324 
  1325 Theorem attributs for selecting and transforming function equations theorems:
  1326 
  1327     [code fun]:        select a theorem as function equation for a specific constant
  1328     [code fun del]:    deselect a theorem as function equation for a specific constant
  1329     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1330     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1331 
  1332 User-defined serializations (target in {SML, OCaml, Haskell}):
  1333 
  1334     code_const <and-list of constants (term syntax)>
  1335       {(target) <and-list of const target syntax>}+
  1336 
  1337     code_type <and-list of type constructors>
  1338       {(target) <and-list of type target syntax>}+
  1339 
  1340     code_instance <and-list of instances>
  1341       {(target)}+
  1342         where instance ::= <type constructor> :: <class>
  1343 
  1344     code_class <and_list of classes>
  1345       {(target) <and-list of class target syntax>}+
  1346         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1347 
  1348 code_instance and code_class only are effective to target Haskell.
  1349 
  1350 For example usage see src/HOL/ex/Codegenerator.thy and
  1351 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1352 generation from Isabelle/HOL theories is available via "isatool doc
  1353 codegen".
  1354 
  1355 * Code generator: consts in 'consts_code' Isar commands are now
  1356 referred to by usual term syntax (including optional type
  1357 annotations).
  1358 
  1359 * Command 'no_translations' removes translation rules from theory
  1360 syntax.
  1361 
  1362 * Overloaded definitions are now actually checked for acyclic
  1363 dependencies.  The overloading scheme is slightly more general than
  1364 that of Haskell98, although Isabelle does not demand an exact
  1365 correspondence to type class and instance declarations.
  1366 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1367 exotic versions of overloading -- at the discretion of the user!
  1368 
  1369 Polymorphic constants are represented via type arguments, i.e. the
  1370 instantiation that matches an instance against the most general
  1371 declaration given in the signature.  For example, with the declaration
  1372 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1373 as c(nat).  Overloading is essentially simultaneous structural
  1374 recursion over such type arguments.  Incomplete specification patterns
  1375 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1376 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1377 Command 'print_theory' outputs the normalized system of recursive
  1378 equations, see section "definitions".
  1379 
  1380 * Configuration options are maintained within the theory or proof
  1381 context (with name and type bool/int/string), providing a very simple
  1382 interface to a poor-man's version of general context data.  Tools may
  1383 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1384 these values using Config.get etc.  Users may change options via an
  1385 associated attribute of the same name.  This form of context
  1386 declaration works particularly well with commands 'declare' or
  1387 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1388 very easy to avoid global references, which would not observe Isar
  1389 toplevel undo/redo and fail to work with multithreading.
  1390 
  1391 Various global ML references of Pure and HOL have been turned into
  1392 configuration options:
  1393 
  1394   Unify.search_bound		unify_search_bound
  1395   Unify.trace_bound		unify_trace_bound
  1396   Unify.trace_simp		unify_trace_simp
  1397   Unify.trace_types		unify_trace_types
  1398   Simplifier.simp_depth_limit	simp_depth_limit
  1399   Blast.depth_limit		blast_depth_limit
  1400   DatatypeProp.dtK		datatype_distinctness_limit
  1401   fast_arith_neq_limit  	fast_arith_neq_limit
  1402   fast_arith_split_limit	fast_arith_split_limit
  1403 
  1404 * Named collections of theorems may be easily installed as context
  1405 data using the functor NamedThmsFun (see also
  1406 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1407 attributes; there is also a toplevel print command.  This facility is
  1408 just a common case of general context data, which is the preferred way
  1409 for anything more complex than just a list of facts in canonical
  1410 order.
  1411 
  1412 * Isar: command 'declaration' augments a local theory by generic
  1413 declaration functions written in ML.  This enables arbitrary content
  1414 being added to the context, depending on a morphism that tells the
  1415 difference of the original declaration context wrt. the application
  1416 context encountered later on.
  1417 
  1418 * Isar: proper interfaces for simplification procedures.  Command
  1419 'simproc_setup' declares named simprocs (with match patterns, and body
  1420 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1421 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1422 
  1423 * Isar: an extra pair of brackets around attribute declarations
  1424 abbreviates a theorem reference involving an internal dummy fact,
  1425 which will be ignored later --- only the effect of the attribute on
  1426 the background context will persist.  This form of in-place
  1427 declarations is particularly useful with commands like 'declare' and
  1428 'using', for example ``have A using [[simproc a]] by simp''.
  1429 
  1430 * Isar: method "assumption" (and implicit closing of subproofs) now
  1431 takes simple non-atomic goal assumptions into account: after applying
  1432 an assumption as a rule the resulting subgoals are solved by atomic
  1433 assumption steps.  This is particularly useful to finish 'obtain'
  1434 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1435 without referring to the original premise "!!x. P x ==> thesis" in the
  1436 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1437 more permissive.
  1438 
  1439 * Isar: implicit use of prems from the Isar proof context is
  1440 considered a legacy feature.  Common applications like ``have A .''
  1441 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1442 referencing facts explicitly here improves readability and
  1443 maintainability of proof texts.
  1444 
  1445 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1446 the obtained context from the course of reasoning!  For example:
  1447 
  1448   assume "EX x y. A x & B y"   -- "any previous fact"
  1449   then guess x and y by clarify
  1450 
  1451 This technique is potentially adventurous, depending on the facts and
  1452 proof tools being involved here.
  1453 
  1454 * Isar: known facts from the proof context may be specified as literal
  1455 propositions, using ASCII back-quote syntax.  This works wherever
  1456 named facts used to be allowed so far, in proof commands, proof
  1457 methods, attributes etc.  Literal facts are retrieved from the context
  1458 according to unification of type and term parameters.  For example,
  1459 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1460 theorems in the current context, then these are valid literal facts:
  1461 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1462 
  1463 There is also a proof method "fact" which does the same composition
  1464 for explicit goal states, e.g. the following proof texts coincide with
  1465 certain special cases of literal facts:
  1466 
  1467   have "A" by fact                 ==  note `A`
  1468   have "A ==> B" by fact           ==  note `A ==> B`
  1469   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1470   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1471 
  1472 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1473 outer syntax.  Thus symbolic identifiers may be used without
  1474 additional white space in declarations like this: ``assume *: A''.
  1475 
  1476 * Isar: 'print_facts' prints all local facts of the current context,
  1477 both named and unnamed ones.
  1478 
  1479 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1480 
  1481   def x == "t" and y == "u"
  1482 
  1483 * Isar: added command 'unfolding', which is structurally similar to
  1484 'using', but affects both the goal state and facts by unfolding given
  1485 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1486 'unfolded' attribute may be replaced by first-class proof text.
  1487 
  1488 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1489 and command 'unfolding' now all support object-level equalities
  1490 (potentially conditional).  The underlying notion of rewrite rule is
  1491 analogous to the 'rule_format' attribute, but *not* that of the
  1492 Simplifier (which is usually more generous).
  1493 
  1494 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1495 premises of a theorem by n. Useful in conjunction with drule.
  1496 
  1497 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1498 method expression within a sandbox consisting of the first N
  1499 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1500 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1501 simplifies all new goals that emerge from applying rule foo to the
  1502 originally first one.
  1503 
  1504 * Isar: schematic goals are no longer restricted to higher-order
  1505 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1506 expected.
  1507 
  1508 * Isar: the conclusion of a long theorem statement is now either
  1509 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1510 (essentially a disjunction of cases with local parameters and
  1511 assumptions).  The latter allows to express general elimination rules
  1512 adequately; in this notation common elimination rules look like this:
  1513 
  1514   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1515     assumes "EX x. P x"
  1516     obtains x where "P x"
  1517 
  1518   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1519     assumes "A & B"
  1520     obtains A and B
  1521 
  1522   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1523     assumes "A | B"
  1524     obtains
  1525       A
  1526     | B
  1527 
  1528 The subsequent classical rules even refer to the formal "thesis"
  1529 explicitly:
  1530 
  1531   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1532     obtains "~ thesis"
  1533 
  1534   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1535     obtains "thesis ==> something"
  1536 
  1537 The actual proof of an 'obtains' statement is analogous to that of the
  1538 Isar proof element 'obtain', only that there may be several cases.
  1539 Optional case names may be specified in parentheses; these will be
  1540 available both in the present proof and as annotations in the
  1541 resulting rule, for later use with the 'cases' method (cf. attribute
  1542 case_names).
  1543 
  1544 * Isar: the assumptions of a long theorem statement are available as
  1545 "assms" fact in the proof context.  This is more appropriate than the
  1546 (historical) "prems", which refers to all assumptions of the current
  1547 context, including those from the target locale, proof body etc.
  1548 
  1549 * Isar: 'print_statement' prints theorems from the current theory or
  1550 proof context in long statement form, according to the syntax of a
  1551 top-level lemma.
  1552 
  1553 * Isar: 'obtain' takes an optional case name for the local context
  1554 introduction rule (default "that").
  1555 
  1556 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1557 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1558 to occur.
  1559 
  1560 * Pure: syntax "CONST name" produces a fully internalized constant
  1561 according to the current context.  This is particularly useful for
  1562 syntax translations that should refer to internal constant
  1563 representations independently of name spaces.
  1564 
  1565 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1566 instead of "FOO ". This allows multiple binder declarations to coexist
  1567 in the same context.  INCOMPATIBILITY.
  1568 
  1569 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1570 primitive that also works in a locale context (both for constants and
  1571 fixed variables). Type declaration and internal syntactic representation
  1572 of given constants retrieved from the context. Likewise, the
  1573 'no_notation' command allows to remove given syntax annotations from the
  1574 current context.
  1575 
  1576 * Isar/locales: new derived specification elements 'axiomatization',
  1577 'definition', 'abbreviation', which support type-inference, admit
  1578 object-level specifications (equality, equivalence).  See also the
  1579 isar-ref manual.  Examples:
  1580 
  1581   axiomatization
  1582     eq  (infix "===" 50) where
  1583     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1584 
  1585   definition "f x y = x + y + 1"
  1586   definition g where "g x = f x x"
  1587 
  1588   abbreviation
  1589     neq  (infix "=!=" 50) where
  1590     "x =!= y == ~ (x === y)"
  1591 
  1592 These specifications may be also used in a locale context.  Then the
  1593 constants being introduced depend on certain fixed parameters, and the
  1594 constant name is qualified by the locale base name.  An internal
  1595 abbreviation takes care for convenient input and output, making the
  1596 parameters implicit and using the original short name.  See also
  1597 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1598 entities from a monomorphic theory.
  1599 
  1600 Presently, abbreviations are only available 'in' a target locale, but
  1601 not inherited by general import expressions.  Also note that
  1602 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1603 'translations' in common applications.  The "no_abbrevs" print mode
  1604 prevents folding of abbreviations in term output.
  1605 
  1606 Concrete syntax is attached to specified constants in internal form,
  1607 independently of name spaces.  The parse tree representation is
  1608 slightly different -- use 'notation' instead of raw 'syntax', and
  1609 'translations' with explicit "CONST" markup to accommodate this.
  1610 
  1611 * Pure/Isar: unified syntax for new-style specification mechanisms
  1612 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1613 full type inference and dummy patterns ("_").  For example:
  1614 
  1615   definition "K x _ = x"
  1616 
  1617   inductive conj for A B
  1618   where "A ==> B ==> conj A B"
  1619 
  1620 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1621 the current context.  Print mode "no_abbrevs" prevents inversion of
  1622 abbreviations on output.
  1623 
  1624 * Isar/locales: improved parameter handling: use of locales "var" and
  1625 "struct" no longer necessary; - parameter renamings are no longer
  1626 required to be injective.  For example, this allows to define
  1627 endomorphisms as locale endom = homom mult mult h.
  1628 
  1629 * Isar/locales: changed the way locales with predicates are defined.
  1630 Instead of accumulating the specification, the imported expression is
  1631 now an interpretation.  INCOMPATIBILITY: different normal form of
  1632 locale expressions.  In particular, in interpretations of locales with
  1633 predicates, goals repesenting already interpreted fragments are not
  1634 removed automatically.  Use methods `intro_locales' and
  1635 `unfold_locales'; see below.
  1636 
  1637 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1638 provide backward reasoning on locales predicates.  The methods are
  1639 aware of interpretations and discharge corresponding goals.
  1640 `intro_locales' is less aggressive then `unfold_locales' and does not
  1641 unfold predicates to assumptions.
  1642 
  1643 * Isar/locales: the order in which locale fragments are accumulated
  1644 has changed.  This enables to override declarations from fragments due
  1645 to interpretations -- for example, unwanted simp rules.
  1646 
  1647 * Isar/locales: interpretation in theories and proof contexts has been
  1648 extended.  One may now specify (and prove) equations, which are
  1649 unfolded in interpreted theorems.  This is useful for replacing
  1650 defined concepts (constants depending on locale parameters) by
  1651 concepts already existing in the target context.  Example:
  1652 
  1653   interpretation partial_order ["op <= :: [int, int] => bool"]
  1654     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1655 
  1656 Typically, the constant `partial_order.less' is created by a
  1657 definition specification element in the context of locale
  1658 partial_order.
  1659 
  1660 * Method "induct": improved internal context management to support
  1661 local fixes and defines on-the-fly. Thus explicit meta-level
  1662 connectives !!  and ==> are rarely required anymore in inductive goals
  1663 (using object-logic connectives for this purpose has been long
  1664 obsolete anyway). Common proof patterns are explained in
  1665 src/HOL/Induct/Common_Patterns.thy, see also
  1666 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1667 examples.
  1668 
  1669 * Method "induct": improved handling of simultaneous goals. Instead of
  1670 introducing object-level conjunction, the statement is now split into
  1671 several conclusions, while the corresponding symbolic cases are nested
  1672 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1673 see src/HOL/Induct/Common_Patterns.thy, for example.
  1674 
  1675 * Method "induct": mutual induction rules are now specified as a list
  1676 of rule sharing the same induction cases. HOL packages usually provide
  1677 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1678 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1679 mutual induction rules differently, i.e. like this:
  1680 
  1681   (induct rule: foo_bar.inducts)
  1682   (induct set: foo bar)
  1683   (induct pred: foo bar)
  1684   (induct type: foo bar)
  1685 
  1686 The ML function ProjectRule.projections turns old-style rules into the
  1687 new format.
  1688 
  1689 * Method "coinduct": dual of induction, see
  1690 src/HOL/Library/Coinductive_List.thy for various examples.
  1691 
  1692 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1693 considered a legacy feature.
  1694 
  1695 * Attribute "symmetric" produces result with standardized schematic
  1696 variables (index 0).  Potential INCOMPATIBILITY.
  1697 
  1698 * Simplifier: by default the simplifier trace only shows top level
  1699 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1700 default. Thus there is less danger of being flooded by the trace. The
  1701 trace indicates where parts have been suppressed.
  1702   
  1703 * Provers/classical: removed obsolete classical version of elim_format
  1704 attribute; classical elim/dest rules are now treated uniformly when
  1705 manipulating the claset.
  1706 
  1707 * Provers/classical: stricter checks to ensure that supplied intro,
  1708 dest and elim rules are well-formed; dest and elim rules must have at
  1709 least one premise.
  1710 
  1711 * Provers/classical: attributes dest/elim/intro take an optional
  1712 weight argument for the rule (just as the Pure versions).  Weights are
  1713 ignored by automated tools, but determine the search order of single
  1714 rule steps.
  1715 
  1716 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1717 where the body does not mention the bound variable.  Note that dummy
  1718 patterns implicitly depend on their context of bounds, which makes
  1719 "{_. _}" match any set comprehension as expected.  Potential
  1720 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1721 constant "_idtdummy" in the binding position.
  1722 
  1723 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1724 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1725 for example "A -> B" => "Pi A (%_. B)".
  1726 
  1727 * Pure: 'class_deps' command visualizes the subclass relation, using
  1728 the graph browser tool.
  1729 
  1730 * Pure: 'print_theory' now suppresses certain internal declarations by
  1731 default; use '!' option for full details.
  1732 
  1733 
  1734 *** HOL ***
  1735 
  1736 * Method "metis" proves goals by applying the Metis general-purpose
  1737 resolution prover (see also http://gilith.com/software/metis/).
  1738 Examples are in the directory MetisExamples.  WARNING: the
  1739 Isabelle/HOL-Metis integration does not yet work properly with
  1740 multi-threading.
  1741   
  1742 * Command 'sledgehammer' invokes external automatic theorem provers as
  1743 background processes.  It generates calls to the "metis" method if
  1744 successful. These can be pasted into the proof.  Users do not have to
  1745 wait for the automatic provers to return.  WARNING: does not really
  1746 work with multi-threading.
  1747 
  1748 * New "auto_quickcheck" feature tests outermost goal statements for
  1749 potential counter-examples.  Controlled by ML references
  1750 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1751 5000 milliseconds).  Fails silently if statements is outside of
  1752 executable fragment, or any other codgenerator problem occurs.
  1753 
  1754 * New constant "undefined" with axiom "undefined x = undefined".
  1755 
  1756 * Added class "HOL.eq", allowing for code generation with polymorphic
  1757 equality.
  1758 
  1759 * Some renaming of class constants due to canonical name prefixing in
  1760 the new 'class' package:
  1761 
  1762     HOL.abs ~> HOL.abs_class.abs
  1763     HOL.divide ~> HOL.divide_class.divide
  1764     0 ~> HOL.zero_class.zero
  1765     1 ~> HOL.one_class.one
  1766     op + ~> HOL.plus_class.plus
  1767     op - ~> HOL.minus_class.minus
  1768     uminus ~> HOL.minus_class.uminus
  1769     op * ~> HOL.times_class.times
  1770     op < ~> HOL.ord_class.less
  1771     op <= > HOL.ord_class.less_eq
  1772     Nat.power ~> Power.power_class.power
  1773     Nat.size ~> Nat.size_class.size
  1774     Numeral.number_of ~> Numeral.number_class.number_of
  1775     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1776     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1777     Orderings.min ~> Orderings.ord_class.min
  1778     Orderings.max ~> Orderings.ord_class.max
  1779     Divides.op div ~> Divides.div_class.div
  1780     Divides.op mod ~> Divides.div_class.mod
  1781     Divides.op dvd ~> Divides.div_class.dvd
  1782 
  1783 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1784 
  1785 a) User-defined constants using any of the names "plus", "minus",
  1786 "times", "less" or "less_eq". The standard syntax translations for
  1787 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1788 names.
  1789 
  1790 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1791 INCOMPATIBILITY: use more specific names.
  1792 
  1793 c) Permutative equations (e.g. "a + b = b + a")
  1794 Since the change of names also changes the order of terms, permutative
  1795 rewrite rules may get applied in a different order. Experience shows
  1796 that this is rarely the case (only two adaptions in the whole Isabelle
  1797 distribution).  INCOMPATIBILITY: rewrite proofs
  1798 
  1799 d) ML code directly refering to constant names
  1800 This in general only affects hand-written proof tactics, simprocs and
  1801 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1802 Consider using @{const_name} antiquotation.
  1803 
  1804 * New class "default" with associated constant "default".
  1805 
  1806 * Function "sgn" is now overloaded and available on int, real, complex
  1807 (and other numeric types), using class "sgn".  Two possible defs of
  1808 sgn are given as equational assumptions in the classes sgn_if and
  1809 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1810 INCOMPATIBILITY.
  1811 
  1812 * Locale "partial_order" now unified with class "order" (cf. theory
  1813 Orderings), added parameter "less".  INCOMPATIBILITY.
  1814 
  1815 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1816 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1817 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1818 
  1819 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1820 changed order of proof goals in instance proofs.
  1821 
  1822 * The transitivity reasoner for partial and linear orders is set up
  1823 for classes "order" and "linorder".  Instances of the reasoner are available
  1824 in all contexts importing or interpreting the corresponding locales.
  1825 Method "order" invokes the reasoner separately; the reasoner
  1826 is also integrated with the Simplifier as a solver.  Diagnostic
  1827 command 'print_orders' shows the available instances of the reasoner
  1828 in the current context.
  1829 
  1830 * Localized monotonicity predicate in theory "Orderings"; integrated
  1831 lemmas max_of_mono and min_of_mono with this predicate.
  1832 INCOMPATIBILITY.
  1833 
  1834 * Formulation of theorem "dense" changed slightly due to integration
  1835 with new class dense_linear_order.
  1836 
  1837 * Uniform lattice theory development in HOL.
  1838 
  1839     constants "meet" and "join" now named "inf" and "sup"
  1840     constant "Meet" now named "Inf"
  1841 
  1842     classes "meet_semilorder" and "join_semilorder" now named
  1843       "lower_semilattice" and "upper_semilattice"
  1844     class "lorder" now named "lattice"
  1845     class "comp_lat" now named "complete_lattice"
  1846 
  1847     Instantiation of lattice classes allows explicit definitions
  1848     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1849 
  1850   INCOMPATIBILITY.  Theorem renames:
  1851 
  1852     meet_left_le            ~> inf_le1
  1853     meet_right_le           ~> inf_le2
  1854     join_left_le            ~> sup_ge1
  1855     join_right_le           ~> sup_ge2
  1856     meet_join_le            ~> inf_sup_ord
  1857     le_meetI                ~> le_infI
  1858     join_leI                ~> le_supI
  1859     le_meet                 ~> le_inf_iff
  1860     le_join                 ~> ge_sup_conv
  1861     meet_idempotent         ~> inf_idem
  1862     join_idempotent         ~> sup_idem
  1863     meet_comm               ~> inf_commute
  1864     join_comm               ~> sup_commute
  1865     meet_leI1               ~> le_infI1
  1866     meet_leI2               ~> le_infI2
  1867     le_joinI1               ~> le_supI1
  1868     le_joinI2               ~> le_supI2
  1869     meet_assoc              ~> inf_assoc
  1870     join_assoc              ~> sup_assoc
  1871     meet_left_comm          ~> inf_left_commute
  1872     meet_left_idempotent    ~> inf_left_idem
  1873     join_left_comm          ~> sup_left_commute
  1874     join_left_idempotent    ~> sup_left_idem
  1875     meet_aci                ~> inf_aci
  1876     join_aci                ~> sup_aci
  1877     le_def_meet             ~> le_iff_inf
  1878     le_def_join             ~> le_iff_sup
  1879     join_absorp2            ~> sup_absorb2
  1880     join_absorp1            ~> sup_absorb1
  1881     meet_absorp1            ~> inf_absorb1
  1882     meet_absorp2            ~> inf_absorb2
  1883     meet_join_absorp        ~> inf_sup_absorb
  1884     join_meet_absorp        ~> sup_inf_absorb
  1885     distrib_join_le         ~> distrib_sup_le
  1886     distrib_meet_le         ~> distrib_inf_le
  1887 
  1888     add_meet_distrib_left   ~> add_inf_distrib_left
  1889     add_join_distrib_left   ~> add_sup_distrib_left
  1890     is_join_neg_meet        ~> is_join_neg_inf
  1891     is_meet_neg_join        ~> is_meet_neg_sup
  1892     add_meet_distrib_right  ~> add_inf_distrib_right
  1893     add_join_distrib_right  ~> add_sup_distrib_right
  1894     add_meet_join_distribs  ~> add_sup_inf_distribs
  1895     join_eq_neg_meet        ~> sup_eq_neg_inf
  1896     meet_eq_neg_join        ~> inf_eq_neg_sup
  1897     add_eq_meet_join        ~> add_eq_inf_sup
  1898     meet_0_imp_0            ~> inf_0_imp_0
  1899     join_0_imp_0            ~> sup_0_imp_0
  1900     meet_0_eq_0             ~> inf_0_eq_0
  1901     join_0_eq_0             ~> sup_0_eq_0
  1902     neg_meet_eq_join        ~> neg_inf_eq_sup
  1903     neg_join_eq_meet        ~> neg_sup_eq_inf
  1904     join_eq_if              ~> sup_eq_if
  1905 
  1906     mono_meet               ~> mono_inf
  1907     mono_join               ~> mono_sup
  1908     meet_bool_eq            ~> inf_bool_eq
  1909     join_bool_eq            ~> sup_bool_eq
  1910     meet_fun_eq             ~> inf_fun_eq
  1911     join_fun_eq             ~> sup_fun_eq
  1912     meet_set_eq             ~> inf_set_eq
  1913     join_set_eq             ~> sup_set_eq
  1914     meet1_iff               ~> inf1_iff
  1915     meet2_iff               ~> inf2_iff
  1916     meet1I                  ~> inf1I
  1917     meet2I                  ~> inf2I
  1918     meet1D1                 ~> inf1D1
  1919     meet2D1                 ~> inf2D1
  1920     meet1D2                 ~> inf1D2
  1921     meet2D2                 ~> inf2D2
  1922     meet1E                  ~> inf1E
  1923     meet2E                  ~> inf2E
  1924     join1_iff               ~> sup1_iff
  1925     join2_iff               ~> sup2_iff
  1926     join1I1                 ~> sup1I1
  1927     join2I1                 ~> sup2I1
  1928     join1I1                 ~> sup1I1
  1929     join2I2                 ~> sup1I2
  1930     join1CI                 ~> sup1CI
  1931     join2CI                 ~> sup2CI
  1932     join1E                  ~> sup1E
  1933     join2E                  ~> sup2E
  1934 
  1935     is_meet_Meet            ~> is_meet_Inf
  1936     Meet_bool_def           ~> Inf_bool_def
  1937     Meet_fun_def            ~> Inf_fun_def
  1938     Meet_greatest           ~> Inf_greatest
  1939     Meet_lower              ~> Inf_lower
  1940     Meet_set_def            ~> Inf_set_def
  1941 
  1942     Sup_def                 ~> Sup_Inf
  1943     Sup_bool_eq             ~> Sup_bool_def
  1944     Sup_fun_eq              ~> Sup_fun_def
  1945     Sup_set_eq              ~> Sup_set_def
  1946 
  1947     listsp_meetI            ~> listsp_infI
  1948     listsp_meet_eq          ~> listsp_inf_eq
  1949 
  1950     meet_min                ~> inf_min
  1951     join_max                ~> sup_max
  1952 
  1953 * Added syntactic class "size"; overloaded constant "size" now has
  1954 type "'a::size ==> bool"
  1955 
  1956 * Internal reorganisation of `size' of datatypes: size theorems
  1957 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1958 simplification rules by default!); theorems "prod.size" now named
  1959 "*.size".
  1960 
  1961 * Class "div" now inherits from class "times" rather than "type".
  1962 INCOMPATIBILITY.
  1963 
  1964 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1965 Linorder etc.  have disappeared; operations defined in terms of
  1966 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1967 
  1968 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1969 
  1970 * HOL-Word: New extensive library and type for generic, fixed size
  1971 machine words, with arithemtic, bit-wise, shifting and rotating
  1972 operations, reflection into int, nat, and bool lists, automation for
  1973 linear arithmetic (by automatic reflection into nat or int), including
  1974 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1975 arithmetic type classes, supporting automatic simplification of
  1976 numerals on all operations.
  1977 
  1978 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1979 
  1980 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1981 
  1982 * Code generator library theories:
  1983   - Code_Integer represents HOL integers by big integer literals in target
  1984     languages.
  1985   - Code_Char represents HOL characters by character literals in target
  1986     languages.
  1987   - Code_Char_chr like Code_Char, but also offers treatment of character
  1988     codes; includes Code_Integer.
  1989   - Executable_Set allows to generate code for finite sets using lists.
  1990   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1991     denominator).
  1992   - Executable_Real implements a subset of real numbers, namly those
  1993     representable by rational numbers.
  1994   - Efficient_Nat implements natural numbers by integers, which in general will
  1995     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1996     includes Code_Integer.
  1997   - Code_Index provides an additional datatype index which is mapped to
  1998     target-language built-in integers.
  1999   - Code_Message provides an additional datatype message_string which is isomorphic to
  2000     strings; messages are mapped to target-language strings.
  2001 
  2002 * New package for inductive predicates
  2003 
  2004   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2005 
  2006     inductive
  2007       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2008       for z_1 :: U_1 and ... and z_n :: U_m
  2009     where
  2010       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2011     | ...
  2012 
  2013   with full support for type-inference, rather than
  2014 
  2015     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2016 
  2017     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2018     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2019 
  2020     inductive "s z_1 ... z_m"
  2021     intros
  2022       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2023       ...
  2024 
  2025   For backward compatibility, there is a wrapper allowing inductive
  2026   sets to be defined with the new package via
  2027 
  2028     inductive_set
  2029       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2030       for z_1 :: U_1 and ... and z_n :: U_m
  2031     where
  2032       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2033     | ...
  2034 
  2035   or
  2036 
  2037     inductive_set
  2038       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2039       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2040       for z_1 :: U_1 and ... and z_n :: U_m
  2041     where
  2042       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2043     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2044     | ...
  2045 
  2046   if the additional syntax "p ..." is required.
  2047 
  2048   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2049   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2050 
  2051   INCOMPATIBILITIES:
  2052 
  2053   - Since declaration and definition of inductive sets or predicates
  2054     is no longer separated, abbreviations involving the newly
  2055     introduced sets or predicates must be specified together with the
  2056     introduction rules after the 'where' keyword (see above), rather
  2057     than before the actual inductive definition.
  2058 
  2059   - The variables in induction and elimination rules are now
  2060     quantified in the order of their occurrence in the introduction
  2061     rules, rather than in alphabetical order. Since this may break
  2062     some proofs, these proofs either have to be repaired, e.g. by
  2063     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2064     statements of the form
  2065 
  2066       case (rule_i a_i_1 ... a_i_{k_i})
  2067 
  2068     or the old order of quantification has to be restored by explicitly adding
  2069     meta-level quantifiers in the introduction rules, i.e.
  2070 
  2071       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2072 
  2073   - The format of the elimination rules is now
  2074 
  2075       p z_1 ... z_m x_1 ... x_n ==>
  2076         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2077         ==> ... ==> P
  2078 
  2079     for predicates and
  2080 
  2081       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2082         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2083         ==> ... ==> P
  2084 
  2085     for sets rather than
  2086 
  2087       x : s z_1 ... z_m ==>
  2088         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2089         ==> ... ==> P
  2090 
  2091     This may require terms in goals to be expanded to n-tuples
  2092     (e.g. using case_tac or simplification with the split_paired_all
  2093     rule) before the above elimination rule is applicable.
  2094 
  2095   - The elimination or case analysis rules for (mutually) inductive
  2096     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2097     list of rules "p_1_..._p_k.elims" is no longer available.
  2098 
  2099 * New package "function"/"fun" for general recursive functions,
  2100 supporting mutual and nested recursion, definitions in local contexts,
  2101 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2102 for small examples, and the separate tutorial on the function
  2103 package. The old recdef "package" is still available as before, but
  2104 users are encouraged to use the new package.
  2105 
  2106 * Method "lexicographic_order" automatically synthesizes termination
  2107 relations as lexicographic combinations of size measures. 
  2108 
  2109 * Case-expressions allow arbitrary constructor-patterns (including
  2110 "_") and take their order into account, like in functional
  2111 programming.  Internally, this is translated into nested
  2112 case-expressions; missing cases are added and mapped to the predefined
  2113 constant "undefined". In complicated cases printing may no longer show
  2114 the original input but the internal form. Lambda-abstractions allow
  2115 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2116 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2117 variable.
  2118 
  2119 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2120 is an abbreviation for "of_nat :: nat => int". The simplification
  2121 rules for "of_nat" have been changed to work like "int" did
  2122 previously.  Potential INCOMPATIBILITY:
  2123   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2124   - of_nat_diff and of_nat_mult are no longer default simp rules
  2125 
  2126 * Method "algebra" solves polynomial equations over (semi)rings using
  2127 Groebner bases. The (semi)ring structure is defined by locales and the
  2128 tool setup depends on that generic context. Installing the method for
  2129 a specific type involves instantiating the locale and possibly adding
  2130 declarations for computation on the coefficients.  The method is
  2131 already instantiated for natural numbers and for the axiomatic class
  2132 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2133 CALCULEMUS 2007 for the general principles underlying this
  2134 architecture of context-aware proof-tools.
  2135 
  2136 * Method "ferrack" implements quantifier elimination over
  2137 special-purpose dense linear orders using locales (analogous to
  2138 "algebra"). The method is already installed for class
  2139 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2140 rat, etc.
  2141 
  2142 * Former constant "List.op @" now named "List.append".  Use ML
  2143 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2144 circumvent possible incompatibilities when working on ML level.
  2145 
  2146 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2147 
  2148 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2149 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2150 
  2151 * New syntax for Haskell-like list comprehension (input only), eg.
  2152 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2153 
  2154 * The special syntax for function "filter" has changed from [x :
  2155 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2156 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2157 
  2158 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2159 defined on nat only, as an abbreviation for [a..<Suc b]
  2160 INCOMPATIBILITY.
  2161 
  2162 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2163 
  2164 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2165 
  2166 * New lemma collection field_simps (an extension of ring_simps) for
  2167 manipulating (in)equations involving division. Multiplies with all
  2168 denominators that can be proved to be non-zero (in equations) or
  2169 positive/negative (in inequations).
  2170 
  2171 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2172 have been improved and renamed to ring_simps, group_simps and
  2173 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2174 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2175 
  2176 * Theory Library/Commutative_Ring: switched from recdef to function
  2177 package; constants add, mul, pow now curried.  Infix syntax for
  2178 algebraic operations.
  2179 
  2180 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2181 INCOMPATIBILITY.
  2182 
  2183 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2184 INCOMPATIBILITY.
  2185 
  2186 * HOL/records: generalised field-update to take a function on the
  2187 field rather than the new value: r(|A := x|) is translated to A_update
  2188 (K x) r The K-combinator that is internally used is called K_record.
  2189 INCOMPATIBILITY: Usage of the plain update functions has to be
  2190 adapted.
  2191  
  2192 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2193 * x = 0, which are required for a semiring.  Richer structures do not
  2194 inherit from semiring_0 anymore, because this property is a theorem
  2195 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2196 there is more to prove, but this is mostly trivial.
  2197 
  2198 * Class "recpower" is generalized to arbitrary monoids, not just
  2199 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2200 commutativity or semiring properties additionally.
  2201 
  2202 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2203 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2204 better use 'abbreviation'.
  2205 
  2206 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2207 
  2208 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2209 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2210 significant changes for setting up numeral syntax for types:
  2211   - New constants Numeral.pred and Numeral.succ instead
  2212       of former Numeral.bin_pred and Numeral.bin_succ.
  2213   - Use integer operations instead of bin_add, bin_mult and so on.
  2214   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2215   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2216 
  2217 See src/HOL/Integ/IntArith.thy for an example setup.
  2218 
  2219 * Command 'normal_form' computes the normal form of a term that may
  2220 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2221 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2222 heavy-duty computations because the functions are compiled to ML
  2223 first.  Correspondingly, a method "normalization" is provided.  See
  2224 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2225 
  2226 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2227 25 like -->); output depends on the "iff" print_mode, the default is
  2228 "A = B" (with priority 50).
  2229 
  2230 * Relations less (<) and less_eq (<=) are also available on type bool.
  2231 Modified syntax to disallow nesting without explicit parentheses,
  2232 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2233 INCOMPATIBILITY.
  2234 
  2235 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2236 
  2237 * Relation composition operator "op O" now has precedence 75 and binds
  2238 stronger than union and intersection. INCOMPATIBILITY.
  2239 
  2240 * The old set interval syntax "{m..n(}" (and relatives) has been
  2241 removed.  Use "{m..<n}" (and relatives) instead.
  2242 
  2243 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2244 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2245 ``declare [[simproc del: neq]]''.
  2246 
  2247 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2248 True/False.
  2249 
  2250 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2251 
  2252 * Theorem setsum_mult renamed to setsum_right_distrib.
  2253 
  2254 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2255 ``rule'' method.
  2256 
  2257 * Reimplemented methods "sat" and "satx", with several improvements:
  2258 goals no longer need to be stated as "<prems> ==> False", equivalences
  2259 (i.e. "=" on type bool) are handled, variable names of the form
  2260 "lit_<n>" are no longer reserved, significant speedup.
  2261 
  2262 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2263 zChaff is still supported as well.
  2264 
  2265 * 'inductive' and 'datatype': provide projections of mutual rules,
  2266 bundled as foo_bar.inducts;
  2267 
  2268 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2269 Library.
  2270 
  2271 * Library: moved theory Accessible_Part to main HOL.
  2272 
  2273 * Library: added theory Coinductive_List of potentially infinite lists
  2274 as greatest fixed-point.
  2275 
  2276 * Library: added theory AssocList which implements (finite) maps as
  2277 association lists.
  2278 
  2279 * Method "evaluation" solves goals (i.e. a boolean expression)
  2280 efficiently by compiling it to ML.  The goal is "proved" (via an
  2281 oracle) if it evaluates to True.
  2282 
  2283 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2284 also when invoked by the simplifier.  This results in the Simplifier
  2285 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2286 Configuration option fast_arith_split_limit=0 recovers the old
  2287 behavior.
  2288 
  2289 * Support for hex (0x20) and binary (0b1001) numerals.
  2290 
  2291 * New method: reify eqs (t), where eqs are equations for an
  2292 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2293 parameter, computes a term s::'b and a list xs::'a list and proves the
  2294 theorem I xs s = t. This is also known as reification or quoting. The
  2295 resulting theorem is applied to the subgoal to substitute t with I xs
  2296 s.  If t is omitted, the subgoal itself is reified.
  2297 
  2298 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2299 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2300 where f is supposed to be a computable function (in the sense of code
  2301 generattion). The method uses reify to compute s and xs as above then
  2302 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2303 r and finally gets the theorem t = r, which is again applied to the
  2304 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2305 
  2306 * Reflection: Automatic reification now handels binding, an example is
  2307 available in src/HOL/ex/ReflectionEx.thy
  2308 
  2309 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2310 command 'statespace' that is similar to 'record', but introduces an
  2311 abstract specification based on the locale infrastructure instead of
  2312 HOL types.  This leads to extra flexibility in composing state spaces,
  2313 in particular multiple inheritance and renaming of components.
  2314 
  2315 
  2316 *** HOL-Complex ***
  2317 
  2318 * Hyperreal: Functions root and sqrt are now defined on negative real
  2319 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2320 Nonnegativity side conditions have been removed from many lemmas, so
  2321 that more subgoals may now be solved by simplification; potential
  2322 INCOMPATIBILITY.
  2323 
  2324 * Real: new type classes formalize real normed vector spaces and
  2325 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2326 and norm :: 'a => real.
  2327 
  2328 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2329 reals into other types. The overloaded constant Reals :: 'a set is now
  2330 defined as range of_real; potential INCOMPATIBILITY.
  2331 
  2332 * Real: proper support for ML code generation, including 'quickcheck'.
  2333 Reals are implemented as arbitrary precision rationals.
  2334 
  2335 * Hyperreal: Several constants that previously worked only for the
  2336 reals have been generalized, so they now work over arbitrary vector
  2337 spaces. Type annotations may need to be added in some cases; potential
  2338 INCOMPATIBILITY.
  2339 
  2340   Infinitesimal  :: ('a::real_normed_vector) star set
  2341   HFinite        :: ('a::real_normed_vector) star set
  2342   HInfinite      :: ('a::real_normed_vector) star set
  2343   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2344   monad          :: ('a::real_normed_vector) star => 'a star set
  2345   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2346   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2347   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2348   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2349   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2350   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2351   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2352   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2353   sgn            :: 'a::real_normed_vector => 'a
  2354   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2355 
  2356 * Complex: Some complex-specific constants are now abbreviations for
  2357 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2358 hnorm.  Other constants have been entirely removed in favor of the
  2359 polymorphic versions (INCOMPATIBILITY):
  2360 
  2361   approx        <-- capprox
  2362   HFinite       <-- CFinite
  2363   HInfinite     <-- CInfinite
  2364   Infinitesimal <-- CInfinitesimal
  2365   monad         <-- cmonad
  2366   galaxy        <-- cgalaxy
  2367   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2368   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2369   (ns)deriv     <-- (ns)cderiv
  2370 
  2371 
  2372 *** HOL-Algebra ***
  2373 
  2374 * Formalisation of ideals and the quotient construction over rings.
  2375 
  2376 * Order and lattice theory no longer based on records.
  2377 INCOMPATIBILITY.
  2378 
  2379 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2380 greatest_closed.  INCOMPATIBILITY.
  2381 
  2382 * Method algebra is now set up via an attribute.  For examples see
  2383 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2384 of algebraic structures.
  2385 
  2386 * Renamed theory CRing to Ring.
  2387 
  2388 
  2389 *** HOL-Nominal ***
  2390 
  2391 * Substantial, yet incomplete support for nominal datatypes (binding
  2392 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2393 src/HOL/Nominal/Examples.  Prospective users should consult
  2394 http://isabelle.in.tum.de/nominal/
  2395 
  2396 
  2397 *** ML ***
  2398 
  2399 * ML basics: just one true type int, which coincides with IntInf.int
  2400 (even on SML/NJ).
  2401 
  2402 * ML within Isar: antiquotations allow to embed statically-checked
  2403 formal entities in the source, referring to the context available at
  2404 compile-time.  For example:
  2405 
  2406 ML {* @{sort "{zero,one}"} *}
  2407 ML {* @{typ "'a => 'b"} *}
  2408 ML {* @{term "%x. x"} *}
  2409 ML {* @{prop "x == y"} *}
  2410 ML {* @{ctyp "'a => 'b"} *}
  2411 ML {* @{cterm "%x. x"} *}
  2412 ML {* @{cprop "x == y"} *}
  2413 ML {* @{thm asm_rl} *}
  2414 ML {* @{thms asm_rl} *}
  2415 ML {* @{type_name c} *}
  2416 ML {* @{type_syntax c} *}
  2417 ML {* @{const_name c} *}
  2418 ML {* @{const_syntax c} *}
  2419 ML {* @{context} *}
  2420 ML {* @{theory} *}
  2421 ML {* @{theory Pure} *}
  2422 ML {* @{theory_ref} *}
  2423 ML {* @{theory_ref Pure} *}
  2424 ML {* @{simpset} *}
  2425 ML {* @{claset} *}
  2426 ML {* @{clasimpset} *}
  2427 
  2428 The same works for sources being ``used'' within an Isar context.
  2429 
  2430 * ML in Isar: improved error reporting; extra verbosity with
  2431 ML_Context.trace enabled.
  2432 
  2433 * Pure/General/table.ML: the join operations now works via exceptions
  2434 DUP/SAME instead of type option. This is simpler in simple cases, and
  2435 admits slightly more efficient complex applications.
  2436 
  2437 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2438 use Context.generic instead of just theory.
  2439 
  2440 * Pure: datatype Context.generic joins theory/Proof.context and
  2441 provides some facilities for code that works in either kind of
  2442 context, notably GenericDataFun for uniform theory and proof data.
  2443 
  2444 * Pure: simplified internal attribute type, which is now always
  2445 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2446 local (Proof.context) attributes have been discontinued, while
  2447 minimizing code duplication. Thm.rule_attribute and
  2448 Thm.declaration_attribute build canonical attributes; see also structure
  2449 Context for further operations on Context.generic, notably
  2450 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2451 declarations and definitions.
  2452 
  2453 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2454 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2455 init only required for impure data. INCOMPATIBILITY: empty really need
  2456 to be empty (no dependencies on theory content!)
  2457 
  2458 * Pure/kernel: consts certification ignores sort constraints given in
  2459 signature declarations. (This information is not relevant to the
  2460 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2461 potential INCOMPATIBILITY.
  2462 
  2463 * Pure: axiomatic type classes are now purely definitional, with
  2464 explicit proofs of class axioms and super class relations performed
  2465 internally. See Pure/axclass.ML for the main internal interfaces --
  2466 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2467 AxClass.axiomatize_class/classrel/arity supersede
  2468 Sign.add_classes/classrel/arities.
  2469 
  2470 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2471 global/local versions on theory vs. Proof.context have been
  2472 discontinued; Attrib.syntax and Method.syntax have been adapted
  2473 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2474 attributes, methods, etc.
  2475 
  2476 * Pure: several functions of signature "... -> theory -> theory * ..."
  2477 have been reoriented to "... -> theory -> ... * theory" in order to
  2478 allow natural usage in combination with the ||>, ||>>, |-> and
  2479 fold_map combinators.
  2480 
  2481 * Pure: official theorem names (closed derivations) and additional
  2482 comments (tags) are now strictly separate.  Name hints -- which are
  2483 maintained as tags -- may be attached any time without affecting the
  2484 derivation.
  2485 
  2486 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2487 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2488 achieve the old behaviour.
  2489 
  2490 * Pure: the "Goal" constant is now called "prop", supporting a
  2491 slightly more general idea of ``protecting'' meta-level rule
  2492 statements.
  2493 
  2494 * Pure: Logic.(un)varify only works in a global context, which is now
  2495 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2496 Logic.legacy_(un)varify as temporary workaround.
  2497 
  2498 * Pure: structure Name provides scalable operations for generating
  2499 internal variable names, notably Name.variants etc.  This replaces
  2500 some popular functions from term.ML:
  2501 
  2502   Term.variant		->  Name.variant
  2503   Term.variantlist	->  Name.variant_list
  2504   Term.invent_names	->  Name.invent_list
  2505 
  2506 Note that low-level renaming rarely occurs in new code -- operations
  2507 from structure Variable are used instead (see below).
  2508 
  2509 * Pure: structure Variable provides fundamental operations for proper
  2510 treatment of fixed/schematic variables in a context.  For example,
  2511 Variable.import introduces fixes for schematics of given facts and
  2512 Variable.export reverses the effect (up to renaming) -- this replaces
  2513 various freeze_thaw operations.
  2514 
  2515 * Pure: structure Goal provides simple interfaces for
  2516 init/conclude/finish and tactical prove operations (replacing former
  2517 Tactic.prove).  Goal.prove is the canonical way to prove results
  2518 within a given context; Goal.prove_global is a degraded version for
  2519 theory level goals, including a global Drule.standard.  Note that
  2520 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2521 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2522 in a locale context).
  2523 
  2524 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2525 and type checking (Syntax.check_term etc.), with common combinations
  2526 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2527 which are considered legacy and await removal.
  2528 
  2529 * Pure/Syntax: generic interfaces for type unchecking
  2530 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2531 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2532 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2533 available for convenience, but refer to the very same operations using
  2534 a mere theory instead of a full context.
  2535 
  2536 * Isar: simplified treatment of user-level errors, using exception
  2537 ERROR of string uniformly.  Function error now merely raises ERROR,
  2538 without any side effect on output channels.  The Isar toplevel takes
  2539 care of proper display of ERROR exceptions.  ML code may use plain
  2540 handle/can/try; cat_error may be used to concatenate errors like this:
  2541 
  2542   ... handle ERROR msg => cat_error msg "..."
  2543 
  2544 Toplevel ML code (run directly or through the Isar toplevel) may be
  2545 embedded into the Isar toplevel with exception display/debug like
  2546 this:
  2547 
  2548   Isar.toplevel (fn () => ...)
  2549 
  2550 INCOMPATIBILITY, removed special transform_error facilities, removed
  2551 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2552 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2553 -- use plain ERROR instead.
  2554 
  2555 * Isar: theory setup now has type (theory -> theory), instead of a
  2556 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2557 
  2558 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2559 ProofContext.debug/verbose flags.
  2560 
  2561 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2562 theory before entering a proof state.  Transactions now always see a
  2563 quasi-functional intermediate checkpoint, both in interactive and
  2564 batch mode.
  2565 
  2566 * Isar: simplified interfaces for outer syntax.  Renamed
  2567 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2568 OuterSyntax.add_parsers -- this functionality is now included in
  2569 OuterSyntax.command etc.  INCOMPATIBILITY.
  2570 
  2571 * Simplifier: the simpset of a running simplification process now
  2572 contains a proof context (cf. Simplifier.the_context), which is the
  2573 very context that the initial simpset has been retrieved from (by
  2574 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2575 (solver, looper etc.) may depend on arbitrary proof data.
  2576 
  2577 * Simplifier.inherit_context inherits the proof context (plus the
  2578 local bounds) of the current simplification process; any simproc
  2579 etc. that calls the Simplifier recursively should do this!  Removed
  2580 former Simplifier.inherit_bounds, which is already included here --
  2581 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2582 specify an explicit context using Simplifier.context/theory_context.
  2583 
  2584 * Simplifier/Classical Reasoner: more abstract interfaces
  2585 change_simpset/claset for modifying the simpset/claset reference of a
  2586 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2587 INCOMPATIBILITY.
  2588 
  2589 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2590 "Trueprop" etc.
  2591 
  2592 
  2593 *** System ***
  2594 
  2595 * settings: the default heap location within ISABELLE_HOME_USER now
  2596 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2597 Isabelle installations.
  2598 
  2599 * isabelle-process: option -S (secure mode) disables some critical
  2600 operations, notably runtime compilation and evaluation of ML source
  2601 code.
  2602 
  2603 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2604 
  2605 * Support for parallel execution, using native multicore support of
  2606 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2607 independent theories, according to the given theory header
  2608 specifications. The maximum number of worker threads is specified via
  2609 usedir option -M or the "max-threads" setting in Proof General. A
  2610 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2611 to 6 on a 8-core machine.  User-code needs to observe certain
  2612 guidelines for thread-safe programming, see appendix A in the Isar
  2613 Implementation manual.
  2614 
  2615 
  2616 
  2617 New in Isabelle2005 (October 2005)
  2618 ----------------------------------
  2619 
  2620 *** General ***
  2621 
  2622 * Theory headers: the new header syntax for Isar theories is
  2623 
  2624   theory <name>
  2625   imports <theory1> ... <theoryN>
  2626   uses <file1> ... <fileM>
  2627   begin
  2628 
  2629 where the 'uses' part is optional.  The previous syntax
  2630 
  2631   theory <name> = <theory1> + ... + <theoryN>:
  2632 
  2633 will disappear in the next release.  Use isatool fixheaders to convert
  2634 existing theory files.  Note that there is no change in ancient
  2635 non-Isar theories now, but these will disappear soon.
  2636 
  2637 * Theory loader: parent theories can now also be referred to via
  2638 relative and absolute paths.
  2639 
  2640 * Command 'find_theorems' searches for a list of criteria instead of a
  2641 list of constants. Known criteria are: intro, elim, dest, name:string,
  2642 simp:term, and any term. Criteria can be preceded by '-' to select
  2643 theorems that do not match. Intro, elim, dest select theorems that
  2644 match the current goal, name:s selects theorems whose fully qualified
  2645 name contain s, and simp:term selects all simplification rules whose
  2646 lhs match term.  Any other term is interpreted as pattern and selects
  2647 all theorems matching the pattern. Available in ProofGeneral under
  2648 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2649 
  2650   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2651 
  2652 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2653 matching the current goal as introduction rule and not having "HOL."
  2654 in their name (i.e. not being defined in theory HOL).
  2655 
  2656 * Command 'thms_containing' has been discontinued in favour of
  2657 'find_theorems'; INCOMPATIBILITY.
  2658 
  2659 * Communication with Proof General is now 8bit clean, which means that
  2660 Unicode text in UTF-8 encoding may be used within theory texts (both
  2661 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2662 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2663 
  2664   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2665   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2666 
  2667 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2668 Classical Reasoner.  Typical big applications run around 2 times
  2669 faster.
  2670 
  2671 
  2672 *** Document preparation ***
  2673 
  2674 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2675 of raw sources.  Only those symbols that do not require additional
  2676 LaTeX packages (depending on comments in isabellesym.sty) are
  2677 displayed properly, everything else is left verbatim.  isatool display
  2678 and isatool print are used as front ends (these are subject to the
  2679 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2680 
  2681 * Command tags control specific markup of certain regions of text,
  2682 notably folding and hiding.  Predefined tags include "theory" (for
  2683 theory begin and end), "proof" for proof commands, and "ML" for
  2684 commands involving ML code; the additional tags "visible" and
  2685 "invisible" are unused by default.  Users may give explicit tag
  2686 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2687 interpretation of tags is determined by the LaTeX job during document
  2688 preparation: see option -V of isatool usedir, or options -n and -t of
  2689 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2690 \isadroptag.
  2691 
  2692 Several document versions may be produced at the same time via isatool
  2693 usedir (the generated index.html will link all of them).  Typical
  2694 specifications include ''-V document=theory,proof,ML'' to present
  2695 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2696 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2697 these parts without any formal replacement text.  The Isabelle site
  2698 default settings produce ''document'' and ''outline'' versions as
  2699 specified above.
  2700 
  2701 * Several new antiquotations:
  2702 
  2703   @{term_type term} prints a term with its type annotated;
  2704 
  2705   @{typeof term} prints the type of a term;
  2706 
  2707   @{const const} is the same as @{term const}, but checks that the
  2708   argument is a known logical constant;
  2709 
  2710   @{term_style style term} and @{thm_style style thm} print a term or
  2711   theorem applying a "style" to it
  2712 
  2713   @{ML text}
  2714 
  2715 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2716 definitions, equations, inequations etc., 'concl' printing only the
  2717 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2718 to print the specified premise.  TermStyle.add_style provides an ML
  2719 interface for introducing further styles.  See also the "LaTeX Sugar"
  2720 document practical applications.  The ML antiquotation prints
  2721 type-checked ML expressions verbatim.
  2722 
  2723 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2724 and 'text' support optional locale specification '(in loc)', which
  2725 specifies the default context for interpreting antiquotations.  For
  2726 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2727 
  2728 * Option 'locale=NAME' of antiquotations specifies an alternative
  2729 context interpreting the subsequent argument.  For example: @{thm
  2730 [locale=lattice] inf_assoc}.
  2731 
  2732 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2733 a proof context.
  2734 
  2735 * Proper output of antiquotations for theory commands involving a
  2736 proof context (such as 'locale' or 'theorem (in loc) ...').
  2737 
  2738 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2739 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2740 
  2741 * isatool usedir: new option -C (default true) controls whether option
  2742 -D should include a copy of the original document directory; -C false
  2743 prevents unwanted effects such as copying of administrative CVS data.
  2744 
  2745 
  2746 *** Pure ***
  2747 
  2748 * Considerably improved version of 'constdefs' command.  Now performs
  2749 automatic type-inference of declared constants; additional support for
  2750 local structure declarations (cf. locales and HOL records), see also
  2751 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2752 sequential dependencies of definitions within a single 'constdefs'
  2753 section; moreover, the declared name needs to be an identifier.  If
  2754 all fails, consider to fall back on 'consts' and 'defs' separately.
  2755 
  2756 * Improved indexed syntax and implicit structures.  First of all,
  2757 indexed syntax provides a notational device for subscripted
  2758 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2759 expressions.  Secondly, in a local context with structure
  2760 declarations, number indexes \<^sub>n or the empty index (default
  2761 number 1) refer to a certain fixed variable implicitly; option
  2762 show_structs controls printing of implicit structures.  Typical
  2763 applications of these concepts involve record types and locales.
  2764 
  2765 * New command 'no_syntax' removes grammar declarations (and
  2766 translations) resulting from the given syntax specification, which is
  2767 interpreted in the same manner as for the 'syntax' command.
  2768 
  2769 * 'Advanced' translation functions (parse_translation etc.) may depend
  2770 on the signature of the theory context being presently used for
  2771 parsing/printing, see also isar-ref manual.
  2772 
  2773 * Improved 'oracle' command provides a type-safe interface to turn an
  2774 ML expression of type theory -> T -> term into a primitive rule of
  2775 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2776 is already included here); see also FOL/ex/IffExample.thy;
  2777 INCOMPATIBILITY.
  2778 
  2779 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2780 before); "cI" is no longer bound, use "c.intro" instead.
  2781 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2782 axclasses vs. locales.
  2783 
  2784 * Improved internal renaming of symbolic identifiers -- attach primes
  2785 instead of base 26 numbers.
  2786 
  2787 * New flag show_question_marks controls printing of leading question
  2788 marks in schematic variable names.
  2789 
  2790 * In schematic variable names, *any* symbol following \<^isub> or
  2791 \<^isup> is now treated as part of the base name.  For example, the
  2792 following works without printing of awkward ".0" indexes:
  2793 
  2794   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2795     by simp
  2796 
  2797 * Inner syntax includes (*(*nested*) comments*).
  2798 
  2799 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2800 annotations as "(00...)".
  2801 
  2802 * Clear separation of logical types and nonterminals, where the latter
  2803 may only occur in 'syntax' specifications or type abbreviations.
  2804 Before that distinction was only partially implemented via type class
  2805 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2806 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2807 exotic syntax specifications may require further adaption
  2808 (e.g. Cube/Cube.thy).
  2809 
  2810 * Removed obsolete type class "logic", use the top sort {} instead.
  2811 Note that non-logical types should be declared as 'nonterminals'
  2812 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2813 specifications.
  2814 
  2815 * Attributes 'induct' and 'cases': type or set names may now be
  2816 locally fixed variables as well.
  2817 
  2818 * Simplifier: can now control the depth to which conditional rewriting
  2819 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2820 Limit.
  2821 
  2822 * Simplifier: simplification procedures may now take the current
  2823 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2824 interface), which is very useful for calling the Simplifier
  2825 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2826 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2827 low-level mk_simproc no longer applies Logic.varify internally, to
  2828 allow for use in a context of fixed variables.
  2829 
  2830 * thin_tac now works even if the assumption being deleted contains !!
  2831 or ==>.  More generally, erule now works even if the major premise of
  2832 the elimination rule contains !! or ==>.
  2833 
  2834 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2835 
  2836 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2837 from Pure, which contains all common declarations already.  Both
  2838 theories are defined via plain Isabelle/Isar .thy files.
  2839 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2840 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2841 use isatool fixcpure to adapt your theory and ML sources.
  2842 
  2843 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2844 selections of theorems in named facts via index ranges.
  2845 
  2846 * 'print_theorems': in theory mode, really print the difference
  2847 wrt. the last state (works for interactive theory development only),
  2848 in proof mode print all local facts (cf. 'print_facts');
  2849 
  2850 * 'hide': option '(open)' hides only base names.
  2851 
  2852 * More efficient treatment of intermediate checkpoints in interactive
  2853 theory development.
  2854 
  2855 * Code generator is now invoked via code_module (incremental code
  2856 generation) and code_library (modular code generation, ML structures
  2857 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2858 must be quoted when used as identifiers.
  2859 
  2860 * New 'value' command for reading, evaluating and printing terms using
  2861 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2862 quoted when used as identifier.
  2863 
  2864 
  2865 *** Locales ***
  2866 
  2867 * New commands for the interpretation of locale expressions in
  2868 theories (1), locales (2) and proof contexts (3).  These generate
  2869 proof obligations from the expression specification.  After the
  2870 obligations have been discharged, theorems of the expression are added
  2871 to the theory, target locale or proof context.  The synopsis of the
  2872 commands is a follows:
  2873 
  2874   (1) interpretation expr inst
  2875   (2) interpretation target < expr
  2876   (3) interpret expr inst
  2877 
  2878 Interpretation in theories and proof contexts require a parameter
  2879 instantiation of terms from the current context.  This is applied to
  2880 specifications and theorems of the interpreted expression.
  2881 Interpretation in locales only permits parameter renaming through the
  2882 locale expression.  Interpretation is smart in that interpretations
  2883 that are active already do not occur in proof obligations, neither are
  2884 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2885 inspect active interpretations of a particular locale.  For details,
  2886 see the Isar Reference manual.  Examples can be found in
  2887 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2888 
  2889 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2890 'interpret' instead.
  2891 
  2892 * New context element 'constrains' for adding type constraints to
  2893 parameters.
  2894 
  2895 * Context expressions: renaming of parameters with syntax
  2896 redeclaration.
  2897 
  2898 * Locale declaration: 'includes' disallowed.
  2899 
  2900 * Proper static binding of attribute syntax -- i.e. types / terms /
  2901 facts mentioned as arguments are always those of the locale definition
  2902 context, independently of the context of later invocations.  Moreover,
  2903 locale operations (renaming and type / term instantiation) are applied
  2904 to attribute arguments as expected.
  2905 
  2906 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2907 actual attributes; rare situations may require Attrib.attribute to
  2908 embed those attributes into Attrib.src that lack concrete syntax.
  2909 Attribute implementations need to cooperate properly with the static
  2910 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2911 Attrib.XXX_thm etc. already do the right thing without further
  2912 intervention.  Only unusual applications -- such as "where" or "of"
  2913 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2914 on the context and the facts involved -- may have to assign parsed
  2915 values to argument tokens explicitly.
  2916 
  2917 * Changed parameter management in theorem generation for long goal
  2918 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2919 theorem statement in rare situations.
  2920 
  2921 * Locale inspection command 'print_locale' omits notes elements.  Use
  2922 'print_locale!' to have them included in the output.
  2923 
  2924 
  2925 *** Provers ***
  2926 
  2927 * Provers/hypsubst.ML: improved version of the subst method, for
  2928 single-step rewriting: it now works in bound variable contexts. New is
  2929 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2930 rewrite a different subterm than the original subst method, which is
  2931 still available as 'simplesubst'.
  2932 
  2933 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2934 and quasi orders.
  2935 
  2936 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2937 reflexive-transitive closure of relations.
  2938 
  2939 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2940 limit (previously hard-coded with a value of 20) user-definable.
  2941 
  2942 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2943 is peformed already.  Object-logics merely need to finish their
  2944 initial simpset configuration as before.  INCOMPATIBILITY.
  2945 
  2946 
  2947 *** HOL ***
  2948 
  2949 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2950 
  2951   syntax (epsilon)
  2952     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2953 
  2954 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2955 and x-symbol; use option '-m epsilon' to get it actually printed.
  2956 Moreover, the mathematically important symbolic identifier \<epsilon>
  2957 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2958 
  2959 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2960 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2961 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2962 support corresponding Isar calculations.
  2963 
  2964 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2965 instead of ":".
  2966 
  2967 * theory SetInterval: changed the syntax for open intervals:
  2968 
  2969   Old       New
  2970   {..n(}    {..<n}
  2971   {)n..}    {n<..}
  2972   {m..n(}   {m..<n}
  2973   {)m..n}   {m<..n}
  2974   {)m..n(}  {m<..<n}
  2975 
  2976 The old syntax is still supported but will disappear in the next
  2977 release.  For conversion use the following Emacs search and replace
  2978 patterns (these are not perfect but work quite well):
  2979 
  2980   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2981   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2982 
  2983 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2984 equalities in commutative rings; method 'algebra' provides a generic
  2985 interface.
  2986 
  2987 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2988 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2989 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2990 be a tuple pattern.
  2991 
  2992 Some new syntax forms are available:
  2993 
  2994   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2995   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2996   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2997   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2998 
  2999 The latter form "\<Sum>x < k. e" used to be based on a separate
  3000 function "Summation", which has been discontinued.
  3001 
  3002 * theory Finite_Set: in structured induction proofs, the insert case
  3003 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3004 (insert F x)'.
  3005 
  3006 * The 'refute' command has been extended to support a much larger
  3007 fragment of HOL, including axiomatic type classes, constdefs and
  3008 typedefs, inductive datatypes and recursion.
  3009 
  3010 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3011 Requires zChaff with proof generation to be installed.  See
  3012 HOL/ex/SAT_Examples.thy for examples.
  3013 
  3014 * Datatype induction via method 'induct' now preserves the name of the
  3015 induction variable. For example, when proving P(xs::'a list) by
  3016 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3017 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3018 in unstructured proof scripts.
  3019 
  3020 * Reworked implementation of records.  Improved scalability for
  3021 records with many fields, avoiding performance problems for type
  3022 inference. Records are no longer composed of nested field types, but
  3023 of nested extension types. Therefore the record type only grows linear
  3024 in the number of extensions and not in the number of fields.  The
  3025 top-level (users) view on records is preserved.  Potential
  3026 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3027 old record representation. The type generated for a record is called
  3028 <record_name>_ext_type.
  3029 
  3030 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3031 proofs triggered by a record definition or a simproc (if
  3032 quick_and_dirty is enabled).  Definitions of large records can take
  3033 quite long.
  3034 
  3035 New simproc record_upd_simproc for simplification of multiple record
  3036 updates enabled by default.  Moreover, trivial updates are also
  3037 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3038 occasionally, since simplification is more powerful by default.
  3039 
  3040 * typedef: proper support for polymorphic sets, which contain extra
  3041 type-variables in the term.
  3042 
  3043 * Simplifier: automatically reasons about transitivity chains
  3044 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3045 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3046 old proofs break occasionally as simplification may now solve more
  3047 goals than previously.
  3048 
  3049 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3050 present.  Works for all partial orders (class "order"), in particular
  3051 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3052 just like y <= x.
  3053 
  3054 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3055 bound variable or a constant then the let is unfolded.  Otherwise
  3056 first a is simplified to b, and then f b is simplified to g. If
  3057 possible we abstract b from g arriving at "let x = b in h x",
  3058 otherwise we unfold the let and arrive at g.  The simproc can be
  3059 enabled/disabled by the reference use_let_simproc.  Potential
  3060 INCOMPATIBILITY since simplification is more powerful by default.
  3061 
  3062 * Classical reasoning: the meson method now accepts theorems as arguments.
  3063 
  3064 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3065 jobs to provide advice on the provability of subgoals.
  3066 
  3067 * Theory OrderedGroup and Ring_and_Field: various additions and
  3068 improvements to faciliate calculations involving equalities and
  3069 inequalities.
  3070 
  3071 The following theorems have been eliminated or modified
  3072 (INCOMPATIBILITY):
  3073 
  3074   abs_eq             now named abs_of_nonneg
  3075   abs_of_ge_0        now named abs_of_nonneg
  3076   abs_minus_eq       now named abs_of_nonpos
  3077   imp_abs_id         now named abs_of_nonneg
  3078   imp_abs_neg_id     now named abs_of_nonpos
  3079   mult_pos           now named mult_pos_pos
  3080   mult_pos_le        now named mult_nonneg_nonneg
  3081   mult_pos_neg_le    now named mult_nonneg_nonpos
  3082   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3083   mult_neg           now named mult_neg_neg
  3084   mult_neg_le        now named mult_nonpos_nonpos
  3085 
  3086 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3087      
  3088      zero_le_square
  3089      not_square_less_zero 
  3090 
  3091   The following lemmas have been deleted from Real/RealPow:
  3092   
  3093      realpow_zero_zero
  3094      realpow_two
  3095      realpow_less
  3096      zero_le_power
  3097      realpow_two_le
  3098      abs_realpow_two
  3099      realpow_two_abs     
  3100 
  3101 * Theory Parity: added rules for simplifying exponents.
  3102 
  3103 * Theory List:
  3104 
  3105 The following theorems have been eliminated or modified
  3106 (INCOMPATIBILITY):
  3107 
  3108   list_all_Nil       now named list_all.simps(1)
  3109   list_all_Cons      now named list_all.simps(2)
  3110   list_all_conv      now named list_all_iff
  3111   set_mem_eq         now named mem_iff
  3112 
  3113 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3114 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3115 
  3116 
  3117 *** HOL-Complex ***
  3118 
  3119 * Theory RealDef: better support for embedding natural numbers and
  3120 integers in the reals.
  3121 
  3122 The following theorems have been eliminated or modified
  3123 (INCOMPATIBILITY):
  3124 
  3125   exp_ge_add_one_self  now requires no hypotheses
  3126   real_of_int_add      reversed direction of equality (use [symmetric])
  3127   real_of_int_minus    reversed direction of equality (use [symmetric])
  3128   real_of_int_diff     reversed direction of equality (use [symmetric])
  3129   real_of_int_mult     reversed direction of equality (use [symmetric])
  3130 
  3131 * Theory RComplete: expanded support for floor and ceiling functions.
  3132 
  3133 * Theory Ln is new, with properties of the natural logarithm
  3134 
  3135 * Hyperreal: There is a new type constructor "star" for making
  3136 nonstandard types.  The old type names are now type synonyms:
  3137 
  3138   hypreal = real star
  3139   hypnat = nat star
  3140   hcomplex = complex star
  3141 
  3142 * Hyperreal: Many groups of similarly-defined constants have been
  3143 replaced by polymorphic versions (INCOMPATIBILITY):
  3144 
  3145   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3146 
  3147   starset      <-- starsetNat, starsetC
  3148   *s*          <-- *sNat*, *sc*
  3149   starset_n    <-- starsetNat_n, starsetC_n
  3150   *sn*         <-- *sNatn*, *scn*
  3151   InternalSets <-- InternalNatSets, InternalCSets
  3152 
  3153   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3154   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3155   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3156   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3157   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3158 
  3159 * Hyperreal: Many type-specific theorems have been removed in favor of
  3160 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3161 
  3162   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3163   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3164   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3165   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3166   right_minus <-- hypreal_add_minus
  3167   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3168   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3169   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3170   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3171   mult_1_right <-- hcomplex_mult_one_right
  3172   mult_zero_left <-- hcomplex_mult_zero_left
  3173   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3174   right_distrib <-- hypnat_add_mult_distrib2
  3175   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3176   right_inverse <-- hypreal_mult_inverse
  3177   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3178   order_refl <-- {hypreal,hypnat}_le_refl
  3179   order_trans <-- {hypreal,hypnat}_le_trans
  3180   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3181   order_less_le <-- {hypreal,hypnat}_less_le
  3182   linorder_linear <-- {hypreal,hypnat}_le_linear
  3183   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3184   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3185   add_nonneg_nonneg <-- hypreal_le_add_order
  3186 
  3187 * Hyperreal: Separate theorems having to do with type-specific
  3188 versions of constants have been merged into theorems that apply to the
  3189 new polymorphic constants (INCOMPATIBILITY):
  3190 
  3191   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3192   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3193   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3194   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3195   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3196   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3197   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3198   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3199   STAR_diff <-- {STAR,STARC}_diff
  3200   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3201     STARC_hcomplex_of_complex}_image_subset
  3202   starset_n_Un <-- starset{Nat,C}_n_Un
  3203   starset_n_Int <-- starset{Nat,C}_n_Int
  3204   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3205   starset_n_diff <-- starset{Nat,C}_n_diff
  3206   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3207   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3208   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3209   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3210   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3211   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3212   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3213   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3214   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3215   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3216   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3217   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3218   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3219   starfun_diff <-- starfun{C,RC,CR}_diff
  3220   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3221   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3222   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3223   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3224   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3225   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3226   starfun_Id <-- starfunC_Id
  3227   starfun_approx <-- starfun{Nat,CR}_approx
  3228   starfun_capprox <-- starfun{C,RC}_capprox
  3229   starfun_abs <-- starfunNat_rabs
  3230   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3231   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3232   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3233   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3234   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3235   starfun_add_approx <-- starfunCR_add_approx
  3236   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3237   starfun_divide <-- starfun{C,CR,RC}_divide
  3238   starfun_n <-- starfun{Nat,C}_n
  3239   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3240   starfun_n_add <-- starfun{Nat,C}_n_add
  3241   starfun_n_add_minus <-- starfunNat_n_add_minus
  3242   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3243   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3244   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3245 
  3246   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3247   star_n_minus <-- {hypreal,hcomplex}_minus
  3248   star_n_diff <-- {hypreal,hcomplex}_diff
  3249   star_n_mult <-- {hypreal,hcomplex}_mult
  3250   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3251   star_n_le <-- {hypreal,hypnat}_le
  3252   star_n_less <-- {hypreal,hypnat}_less
  3253   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3254   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3255   star_n_abs <-- hypreal_hrabs
  3256   star_n_divide <-- hcomplex_divide
  3257 
  3258   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3259   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3260   star_of_diff <-- hypreal_of_real_diff
  3261   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3262   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3263   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3264   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3265   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3266   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3267   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3268   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3269   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3270   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3271   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3272   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3273   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3274   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3275   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3276   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3277   star_of_power <-- hypreal_of_real_power
  3278   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3279 
  3280 * Hyperreal: new method "transfer" that implements the transfer
  3281 principle of nonstandard analysis. With a subgoal that mentions
  3282 nonstandard types like "'a star", the command "apply transfer"
  3283 replaces it with an equivalent one that mentions only standard types.
  3284 To be successful, all free variables must have standard types; non-
  3285 standard variables must have explicit universal quantifiers.
  3286 
  3287 * Hyperreal: A theory of Taylor series.
  3288 
  3289 
  3290 *** HOLCF ***
  3291 
  3292 * Discontinued special version of 'constdefs' (which used to support
  3293 continuous functions) in favor of the general Pure one with full
  3294 type-inference.
  3295 
  3296 * New simplification procedure for solving continuity conditions; it
  3297 is much faster on terms with many nested lambda abstractions (cubic
  3298 instead of exponential time).
  3299 
  3300 * New syntax for domain package: selector names are now optional.
  3301 Parentheses should be omitted unless argument is lazy, for example:
  3302 
  3303   domain 'a stream = cons "'a" (lazy "'a stream")
  3304 
  3305 * New command 'fixrec' for defining recursive functions with pattern
  3306 matching; defining multiple functions with mutual recursion is also
  3307 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3308 sinr, or any data constructor defined by the domain package. The given
  3309 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3310 syntax and examples.
  3311 
  3312 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3313 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3314 but the proof obligation additionally includes an admissibility
  3315 requirement. The packages generate instances of class cpo or pcpo,
  3316 with continuity and strictness theorems for Rep and Abs.
  3317 
  3318 * HOLCF: Many theorems have been renamed according to a more standard naming
  3319 scheme (INCOMPATIBILITY):
  3320 
  3321   foo_inject:  "foo$x = foo$y ==> x = y"
  3322   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3323   foo_less:    "(foo$x << foo$y) = (x << y)"
  3324   foo_strict:  "foo$UU = UU"
  3325   foo_defined: "... ==> foo$x ~= UU"
  3326   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3327 
  3328 
  3329 *** ZF ***
  3330 
  3331 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3332 including the First Isomorphism Theorem (on quotienting by the kernel
  3333 of a homomorphism).
  3334 
  3335 * ZF/Simplifier: install second copy of type solver that actually
  3336 makes use of TC rules declared to Isar proof contexts (or locales);
  3337 the old version is still required for ML proof scripts.
  3338 
  3339 
  3340 *** Cube ***
  3341 
  3342 * Converted to Isar theory format; use locales instead of axiomatic
  3343 theories.
  3344 
  3345 
  3346 *** ML ***
  3347 
  3348 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3349 for ||>, ||>>, |>>,
  3350 
  3351 * Pure/library.ML no longer defines its own option datatype, but uses
  3352 that of the SML basis, which has constructors NONE and SOME instead of
  3353 None and Some, as well as exception Option.Option instead of OPTION.
  3354 The functions the, if_none, is_some, is_none have been adapted
  3355 accordingly, while Option.map replaces apsome.
  3356 
  3357 * Pure/library.ML: the exception LIST has been given up in favour of
  3358 the standard exceptions Empty and Subscript, as well as
  3359 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3360 superceded by the standard hd and tl functions etc.
  3361 
  3362 A number of basic list functions are no longer exported to the ML
  3363 toplevel, as they are variants of predefined functions.  The following
  3364 suggests how one can translate existing code:
  3365 
  3366     rev_append xs ys = List.revAppend (xs, ys)
  3367     nth_elem (i, xs) = List.nth (xs, i)
  3368     last_elem xs = List.last xs
  3369     flat xss = List.concat xss
  3370     seq fs = List.app fs
  3371     partition P xs = List.partition P xs
  3372     mapfilter f xs = List.mapPartial f xs
  3373 
  3374 * Pure/library.ML: several combinators for linear functional
  3375 transformations, notably reverse application and composition:
  3376 
  3377   x |> f                f #> g
  3378   (x, y) |-> f          f #-> g
  3379 
  3380 * Pure/library.ML: introduced/changed precedence of infix operators:
  3381 
  3382   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3383   infix 2 ?;
  3384   infix 3 o oo ooo oooo;
  3385   infix 4 ~~ upto downto;
  3386 
  3387 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3388 infix operators.
  3389 
  3390 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3391 fold_map support linear functional transformations and nesting.  For
  3392 example:
  3393 
  3394   fold f [x1, ..., xN] y =
  3395     y |> f x1 |> ... |> f xN
  3396 
  3397   (fold o fold) f [xs1, ..., xsN] y =
  3398     y |> fold f xs1 |> ... |> fold f xsN
  3399 
  3400   fold f [x1, ..., xN] =
  3401     f x1 #> ... #> f xN
  3402 
  3403   (fold o fold) f [xs1, ..., xsN] =
  3404     fold f xs1 #> ... #> fold f xsN
  3405 
  3406 * Pure/library.ML: the following selectors on type 'a option are
  3407 available:
  3408 
  3409   the:               'a option -> 'a  (*partial*)
  3410   these:             'a option -> 'a  where 'a = 'b list
  3411   the_default: 'a -> 'a option -> 'a
  3412   the_list:          'a option -> 'a list
  3413 
  3414 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3415 basic operations for association lists, following natural argument
  3416 order; moreover the explicit equality predicate passed here avoids
  3417 potentially expensive polymorphic runtime equality checks.
  3418 The old functions may be expressed as follows:
  3419 
  3420   assoc = uncurry (AList.lookup (op =))
  3421   assocs = these oo AList.lookup (op =)
  3422   overwrite = uncurry (AList.update (op =)) o swap
  3423 
  3424 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3425 
  3426   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3427   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3428 
  3429 replacing make_keylist and keyfilter (occassionally used)
  3430 Naive rewrites:
  3431 
  3432   make_keylist = AList.make
  3433   keyfilter = AList.find (op =)
  3434 
  3435 * eq_fst and eq_snd now take explicit equality parameter, thus
  3436   avoiding eqtypes. Naive rewrites:
  3437 
  3438     eq_fst = eq_fst (op =)
  3439     eq_snd = eq_snd (op =)
  3440 
  3441 * Removed deprecated apl and apr (rarely used).
  3442   Naive rewrites:
  3443 
  3444     apl (n, op) =>>= curry op n
  3445     apr (op, m) =>>= fn n => op (n, m)
  3446 
  3447 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3448 provides a reasonably efficient light-weight implementation of sets as
  3449 lists.
  3450 
  3451 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3452 few new operations; existing lookup and update are now curried to
  3453 follow natural argument order (for use with fold etc.);
  3454 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3455 
  3456 * Pure/General: output via the Isabelle channels of
  3457 writeln/warning/error etc. is now passed through Output.output, with a
  3458 hook for arbitrary transformations depending on the print_mode
  3459 (cf. Output.add_mode -- the first active mode that provides a output
  3460 function wins).  Already formatted output may be embedded into further
  3461 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3462 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3463 accommodate easy composition of diagnostic messages etc.  Programmers
  3464 rarely need to care about Output.output or Output.raw at all, with
  3465 some notable exceptions: Output.output is required when bypassing the
  3466 standard channels (writeln etc.), or in token translations to produce
  3467 properly formatted results; Output.raw is required when capturing
  3468 already output material that will eventually be presented to the user
  3469 a second time.  For the default print mode, both Output.output and
  3470 Output.raw have no effect.
  3471 
  3472 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3473 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3474 cumulative results are displayed at the end of a batch session.
  3475 
  3476 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3477 replaced by File.platform_path and File.shell_path (with appropriate
  3478 hooks).  This provides a clean interface for unusual systems where the
  3479 internal and external process view of file names are different.
  3480 
  3481 * Pure: more efficient orders for basic syntactic entities: added
  3482 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3483 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3484 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3485 orders now -- potential INCOMPATIBILITY for code that depends on a
  3486 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3487 Library.sort_strings on result).
  3488 
  3489 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3490 fold_types traverse types/terms from left to right, observing natural
  3491 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3492 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3493 
  3494 * Pure: name spaces have been refined, with significant changes of the
  3495 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3496 to extern(_table).  The plain name entry path is superceded by a
  3497 general 'naming' context, which also includes the 'policy' to produce
  3498 a fully qualified name and external accesses of a fully qualified
  3499 name; NameSpace.extend is superceded by context dependent
  3500 Sign.declare_name.  Several theory and proof context operations modify
  3501 the naming context.  Especially note Theory.restore_naming and
  3502 ProofContext.restore_naming to get back to a sane state; note that
  3503 Theory.add_path is no longer sufficient to recover from
  3504 Theory.absolute_path in particular.
  3505 
  3506 * Pure: new flags short_names (default false) and unique_names
  3507 (default true) for controlling output of qualified names.  If
  3508 short_names is set, names are printed unqualified.  If unique_names is
  3509 reset, the name prefix is reduced to the minimum required to achieve
  3510 the original result when interning again, even if there is an overlap
  3511 with earlier declarations.
  3512 
  3513 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3514 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3515 (useful for printing error messages).  INCOMPATIBILITY.
  3516 
  3517 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3518 Theory.theory are now identified, referring to the universal
  3519 Context.theory (see Pure/context.ML).  Actual signature and theory
  3520 content is managed as theory data.  The old code and interfaces were
  3521 spread over many files and structures; the new arrangement introduces
  3522 considerable INCOMPATIBILITY to gain more clarity:
  3523 
  3524   Context -- theory management operations (name, identity, inclusion,
  3525     parents, ancestors, merge, etc.), plus generic theory data;
  3526 
  3527   Sign -- logical signature and syntax operations (declaring consts,
  3528     types, etc.), plus certify/read for common entities;
  3529 
  3530   Theory -- logical theory operations (stating axioms, definitions,
  3531     oracles), plus a copy of logical signature operations (consts,
  3532     types, etc.); also a few basic management operations (Theory.copy,
  3533     Theory.merge, etc.)
  3534 
  3535 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3536 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3537 for convenience -- they merely return the theory.
  3538 
  3539 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3540 
  3541 * Pure: the Isar proof context type is already defined early in Pure
  3542 as Context.proof (note that ProofContext.context and Proof.context are
  3543 aliases, where the latter is the preferred name).  This enables other
  3544 Isabelle components to refer to that type even before Isar is present.
  3545 
  3546 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3547 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3548 any of these kinds.  For example, Sign.intern typeK is now
  3549 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3550 Theory.hide_types.  Also note that former
  3551 Theory.hide_classes/types/consts are now
  3552 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3553 internalize their arguments!  INCOMPATIBILITY.
  3554 
  3555 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3556 datatype thmref (with constructors Name and NameSelection) instead of
  3557 plain string -- INCOMPATIBILITY;
  3558 
  3559 * Pure: cases produced by proof methods specify options, where NONE
  3560 means to remove case bindings -- INCOMPATIBILITY in
  3561 (RAW_)METHOD_CASES.
  3562 
  3563 * Pure: the following operations retrieve axioms or theorems from a
  3564 theory node or theory hierarchy, respectively:
  3565 
  3566   Theory.axioms_of: theory -> (string * term) list
  3567   Theory.all_axioms_of: theory -> (string * term) list
  3568   PureThy.thms_of: theory -> (string * thm) list
  3569   PureThy.all_thms_of: theory -> (string * thm) list
  3570 
  3571 * Pure: print_tac now outputs the goal through the trace channel.
  3572 
  3573 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3574 Reference Toplevel.debug (default false) controls detailed printing
  3575 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3576 controls execution profiling -- set to 1 for time and 2 for space
  3577 (both increase the runtime).
  3578 
  3579 * Isar session: The initial use of ROOT.ML is now always timed,
  3580 i.e. the log will show the actual process times, in contrast to the
  3581 elapsed wall-clock time that the outer shell wrapper produces.
  3582 
  3583 * Simplifier: improved handling of bound variables (nameless
  3584 representation, avoid allocating new strings).  Simprocs that invoke
  3585 the Simplifier recursively should use Simplifier.inherit_bounds to
  3586 avoid local name clashes.  Failure to do so produces warnings
  3587 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3588 for further details.
  3589 
  3590 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3591 bindings for all theorems stored within a given theory; this may help
  3592 in porting non-Isar theories to Isar ones, while keeping ML proof
  3593 scripts for the time being.
  3594 
  3595 * ML operator HTML.with_charset specifies the charset begin used for
  3596 generated HTML files.  For example:
  3597 
  3598   HTML.with_charset "utf-8" use_thy "Hebrew";
  3599   HTML.with_charset "utf-8" use_thy "Chinese";
  3600 
  3601 
  3602 *** System ***
  3603 
  3604 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3605 isabelle, isatool etc.).
  3606 
  3607 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3608 isatool doc, isatool mkdir, display_drafts etc.).
  3609 
  3610 * isatool usedir: option -f allows specification of the ML file to be
  3611 used by Isabelle; default is ROOT.ML.
  3612 
  3613 * New isatool version outputs the version identifier of the Isabelle
  3614 distribution being used.
  3615 
  3616 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3617 (containing Boolean satisfiability problems) into Isabelle/HOL
  3618 theories.
  3619 
  3620 
  3621 
  3622 New in Isabelle2004 (April 2004)
  3623 --------------------------------
  3624 
  3625 *** General ***
  3626 
  3627 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3628   Replaces linorder.ML.
  3629 
  3630 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3631   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3632   (\<a>...\<z>), are now considered normal letters, and can therefore
  3633   be used anywhere where an ASCII letter (a...zA...Z) has until
  3634   now. COMPATIBILITY: This obviously changes the parsing of some
  3635   terms, especially where a symbol has been used as a binder, say
  3636   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3637   as an identifier.  Fix it by inserting a space around former
  3638   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3639   existing theory and ML files.
  3640 
  3641 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3642 
  3643 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3644   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3645   a normal (but invisible) letter. For multiple letter subscripts repeat
  3646   \<^isub> like this: x\<^isub>1\<^isub>2.
  3647 
  3648 * Pure: There are now sub-/superscripts that can span more than one
  3649   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3650   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3651   superscript. The new control characters are not identifier parts.
  3652 
  3653 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3654   content of "..." to the latex file instead of \isacntrl... . The "..."
  3655   may consist of any printable characters excluding the end bracket >.
  3656 
  3657 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3658   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3659   declare constants "final", which prevents their being given a definition
  3660   later.  It is useful for constants whose behaviour is fixed axiomatically
  3661   rather than definitionally, such as the meta-logic connectives.
  3662 
  3663 * Pure: 'instance' now handles general arities with general sorts
  3664   (i.e. intersections of classes),
  3665 
  3666 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3667   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3668   It can be changed to alter the colors/layout of generated pages.
  3669 
  3670 
  3671 *** Isar ***
  3672 
  3673 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3674   cut_tac, subgoal_tac and thin_tac:
  3675   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3676     locales are no longer forced to write Isar proof scripts.
  3677     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3678     emulations.
  3679   - INCOMPATIBILITY: names of variables to be instantiated may no
  3680     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3681     This is consistent with the instantiation attribute "where".
  3682 
  3683 * Attributes "where" and "of":
  3684   - Now take type variables of instantiated theorem into account when reading
  3685     the instantiation string.  This fixes a bug that caused instantiated
  3686     theorems to have too special types in some circumstances.
  3687   - "where" permits explicit instantiations of type variables.
  3688 
  3689 * Calculation commands "moreover" and "also" no longer interfere with
  3690   current facts ("this"), admitting arbitrary combinations with "then"
  3691   and derived forms.
  3692 
  3693 * Locales:
  3694   - Goal statements involving the context element "includes" no longer
  3695     generate theorems with internal delta predicates (those ending on
  3696     "_axioms") in the premise.
  3697     Resolve particular premise with <locale>.intro to obtain old form.
  3698   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3699     specification and "includes" elements in goal statement.
  3700   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3701     [intro?] and [elim?] (respectively) by default.
  3702   - Experimental command for instantiation of locales in proof contexts:
  3703         instantiate <label>[<attrs>]: <loc>
  3704     Instantiates locale <loc> and adds all its theorems to the current context
  3705     taking into account their attributes.  Label and attrs are optional
  3706     modifiers, like in theorem declarations.  If present, names of
  3707     instantiated theorems are qualified with <label>, and the attributes
  3708     <attrs> are applied after any attributes these theorems might have already.
  3709       If the locale has assumptions, a chained fact of the form
  3710     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3711     are derived.  The command does not support old-style locales declared
  3712     with "locale (open)".
  3713       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3714 
  3715 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3716   (Isar) contexts.
  3717 
  3718 
  3719 *** HOL ***
  3720 
  3721 * Proof import: new image HOL4 contains the imported library from
  3722   the HOL4 system with about 2500 theorems. It is imported by
  3723   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3724   can be used like any other Isabelle image.  See
  3725   HOL/Import/HOL/README for more information.
  3726 
  3727 * Simplifier:
  3728   - Much improved handling of linear and partial orders.
  3729     Reasoners for linear and partial orders are set up for type classes
  3730     "linorder" and "order" respectively, and are added to the default simpset
  3731     as solvers.  This means that the simplifier can build transitivity chains
  3732     to solve goals from the assumptions.
  3733   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3734     of blast or auto after simplification become unnecessary because the goal
  3735     is solved by simplification already.
  3736 
  3737 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3738     all proved in axiomatic type classes for semirings, rings and fields.
  3739 
  3740 * Numerics:
  3741   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3742     now formalized using the Ring_and_Field theory mentioned above.
  3743   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3744     than before, because now they are set up once in a generic manner.
  3745   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3746     Look for the general versions in Ring_and_Field (and Power if they concern
  3747     exponentiation).
  3748 
  3749 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3750 
  3751 * Records:
  3752   - Record types are now by default printed with their type abbreviation
  3753     instead of the list of all field types. This can be configured via
  3754     the reference "print_record_type_abbr".
  3755   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3756     (not enabled by default).
  3757   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3758     EX x. x = sel r to True (not enabled by default).
  3759   - Tactic "record_split_simp_tac" to split and simplify records added.
  3760 
  3761 * 'specification' command added, allowing for definition by
  3762   specification.  There is also an 'ax_specification' command that
  3763   introduces the new constants axiomatically.
  3764 
  3765 * arith(_tac) is now able to generate counterexamples for reals as well.
  3766 
  3767 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3768 
  3769 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3770   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3771 
  3772 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3773   matrix theory to linear programming.
  3774 
  3775 * Unions and Intersections:
  3776   The latex output syntax of UN and INT has been changed
  3777   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3778   i.e. the index formulae has become a subscript.
  3779   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3780 
  3781 * Unions and Intersections over Intervals:
  3782   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3783   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3784   like in normal math, and corresponding versions for < and for intersection.
  3785 
  3786 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3787   lexicographic dictonary ordering has been added as "lexord".
  3788 
  3789 * ML: the legacy theory structures Int and List have been removed. They had
  3790   conflicted with ML Basis Library structures having the same names.
  3791 
  3792 * 'refute' command added to search for (finite) countermodels.  Only works
  3793   for a fragment of HOL.  The installation of an external SAT solver is
  3794   highly recommended.  See "HOL/Refute.thy" for details.
  3795 
  3796 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3797   formulae under an assignment of free variables to random values.
  3798   In contrast to 'refute', it can deal with inductive datatypes,
  3799   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3800   for examples.
  3801 
  3802 
  3803 *** HOLCF ***
  3804 
  3805 * Streams now come with concatenation and are part of the HOLCF image
  3806 
  3807 
  3808 
  3809 New in Isabelle2003 (May 2003)
  3810 ------------------------------
  3811 
  3812 *** General ***
  3813 
  3814 * Provers/simplifier:
  3815 
  3816   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3817     Assumptions are now subject to complete mutual simplification,
  3818     not just from left to right. The simplifier now preserves
  3819     the order of assumptions.
  3820 
  3821     Potential INCOMPATIBILITY:
  3822 
  3823     -- simp sometimes diverges where the old version did
  3824        not, e.g. invoking simp on the goal
  3825 
  3826         [| P (f x); y = x; f x = f y |] ==> Q
  3827 
  3828        now gives rise to the infinite reduction sequence
  3829 
  3830         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3831 
  3832        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3833        kind of problem.
  3834 
  3835     -- Tactics combining classical reasoner and simplification (such as auto)
  3836        are also affected by this change, because many of them rely on
  3837        simp. They may sometimes diverge as well or yield a different numbers
  3838        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3839        in case of problems. Sometimes subsequent calls to the classical
  3840        reasoner will fail because a preceeding call to the simplifier too
  3841        eagerly simplified the goal, e.g. deleted redundant premises.
  3842 
  3843   - The simplifier trace now shows the names of the applied rewrite rules
  3844 
  3845   - You can limit the number of recursive invocations of the simplifier
  3846     during conditional rewriting (where the simplifie tries to solve the
  3847     conditions before applying the rewrite rule):
  3848     ML "simp_depth_limit := n"
  3849     where n is an integer. Thus you can force termination where previously
  3850     the simplifier would diverge.
  3851 
  3852   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3853 
  3854   - No longer aborts on failed congruence proof.  Instead, the
  3855     congruence is ignored.
  3856 
  3857 * Pure: New generic framework for extracting programs from constructive
  3858   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3859   as HOL/Extraction for some case studies.
  3860 
  3861 * Pure: The main goal of the proof state is no longer shown by default, only
  3862 the subgoals. This behaviour is controlled by a new flag.
  3863    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3864 (ML: Proof.show_main_goal).
  3865 
  3866 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3867 rules whose conclusion matches subgoal 1:
  3868       PG menu: Isabelle/Isar -> Show me -> matching rules
  3869 The rules are ordered by how closely they match the subgoal.
  3870 In particular, rules that solve a subgoal outright are displayed first
  3871 (or rather last, the way they are printed).
  3872 (ML: ProofGeneral.print_intros())
  3873 
  3874 * Pure: New flag trace_unify_fail causes unification to print
  3875 diagnostic information (PG: in trace buffer) when it fails. This is
  3876 useful for figuring out why single step proofs like rule, erule or
  3877 assumption failed.
  3878 
  3879 * Pure: Locale specifications now produce predicate definitions
  3880 according to the body of text (covering assumptions modulo local
  3881 definitions); predicate "loc_axioms" covers newly introduced text,
  3882 while "loc" is cumulative wrt. all included locale expressions; the
  3883 latter view is presented only on export into the global theory
  3884 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3885 on the old view without predicates;
  3886 
  3887 * Pure: predefined locales "var" and "struct" are useful for sharing
  3888 parameters (as in CASL, for example); just specify something like
  3889 ``var x + var y + struct M'' as import;
  3890 
  3891 * Pure: improved thms_containing: proper indexing of facts instead of
  3892 raw theorems; check validity of results wrt. current name space;
  3893 include local facts of proof configuration (also covers active
  3894 locales), cover fixed variables in index; may use "_" in term
  3895 specification; an optional limit for the number of printed facts may
  3896 be given (the default is 40);
  3897 
  3898 * Pure: disallow duplicate fact bindings within new-style theory files
  3899 (batch-mode only);
  3900 
  3901 * Provers: improved induct method: assumptions introduced by case
  3902 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3903 the goal statement); "foo" still refers to all facts collectively;
  3904 
  3905 * Provers: the function blast.overloaded has been removed: all constants
  3906 are regarded as potentially overloaded, which improves robustness in exchange
  3907 for slight decrease in efficiency;
  3908 
  3909 * Provers/linorder: New generic prover for transitivity reasoning over
  3910 linear orders.  Note: this prover is not efficient!
  3911 
  3912 * Isar: preview of problems to finish 'show' now produce an error
  3913 rather than just a warning (in interactive mode);
  3914 
  3915 
  3916 *** HOL ***
  3917 
  3918 * arith(_tac)
  3919 
  3920  - Produces a counter example if it cannot prove a goal.
  3921    Note that the counter example may be spurious if the goal is not a formula
  3922    of quantifier-free linear arithmetic.
  3923    In ProofGeneral the counter example appears in the trace buffer.
  3924 
  3925  - Knows about div k and mod k where k is a numeral of type nat or int.
  3926 
  3927  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3928    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3929    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3930 
  3931 * simp's arithmetic capabilities have been enhanced a bit: it now
  3932 takes ~= in premises into account (by performing a case split);
  3933 
  3934 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3935 are distributed over a sum of terms;
  3936 
  3937 * New tactic "trans_tac" and method "trans" instantiate
  3938 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3939 "<=", "<" and "=").
  3940 
  3941 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3942 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3943 
  3944 * 'typedef' command has new option "open" to suppress the set
  3945 definition;
  3946 
  3947 * functions Min and Max on finite sets have been introduced (theory
  3948 Finite_Set);
  3949 
  3950 * attribute [symmetric] now works for relations as well; it turns
  3951 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3952 
  3953 * induct over a !!-quantified statement (say !!x1..xn):
  3954   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3955 
  3956 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3957 %x. None. Warning: empty_def now refers to the previously hidden definition
  3958 of the empty set.
  3959 
  3960 * Algebra: formalization of classical algebra.  Intended as base for
  3961 any algebraic development in Isabelle.  Currently covers group theory
  3962 (up to Sylow's theorem) and ring theory (Universal Property of
  3963 Univariate Polynomials).  Contributions welcome;
  3964 
  3965 * GroupTheory: deleted, since its material has been moved to Algebra;
  3966 
  3967 * Complex: new directory of the complex numbers with numeric constants,
  3968 nonstandard complex numbers, and some complex analysis, standard and
  3969 nonstandard (Jacques Fleuriot);
  3970 
  3971 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3972 
  3973 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3974 Fleuriot);
  3975 
  3976 * Real/HahnBanach: updated and adapted to locales;
  3977 
  3978 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3979 Gray and Kramer);
  3980 
  3981 * UNITY: added the Meier-Sanders theory of progress sets;
  3982 
  3983 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3984 as abstract algorithms, instantiated to the JVM;
  3985 
  3986 * Bali: Java source language formalization. Type system, operational
  3987 semantics, axiomatic semantics. Supported language features:
  3988 classes, interfaces, objects,virtual methods, static methods,
  3989 static/instance fields, arrays, access modifiers, definite
  3990 assignment, exceptions.
  3991 
  3992 
  3993 *** ZF ***
  3994 
  3995 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3996 universe, etc.);
  3997 
  3998 * Main ZF: virtually all theories converted to new-style format;
  3999 
  4000 
  4001 *** ML ***
  4002 
  4003 * Pure: Tactic.prove provides sane interface for internal proofs;
  4004 omits the infamous "standard" operation, so this is more appropriate
  4005 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4006 
  4007 * Pure: improved error reporting of simprocs;
  4008 
  4009 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4010 up simprocs;
  4011 
  4012 
  4013 *** Document preparation ***
  4014 
  4015 * uses \par instead of \\ for line breaks in theory text. This may
  4016 shift some page breaks in large documents. To get the old behaviour
  4017 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4018 
  4019 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4020 other packages
  4021 
  4022 * \<euro> now needs package babel/greek instead of marvosym (which
  4023 broke \Rightarrow)
  4024 
  4025 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4026 textcomp package)
  4027 
  4028 
  4029 
  4030 New in Isabelle2002 (March 2002)
  4031 --------------------------------
  4032 
  4033 *** Document preparation ***
  4034 
  4035 * greatly simplified document preparation setup, including more
  4036 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4037 instructive isatool mkdir; users should basically be able to get
  4038 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4039 users may run a separate document processing stage manually like this:
  4040 "isatool usedir -D output HOL Test && isatool document Test/output";
  4041 
  4042 * theory dependency graph may now be incorporated into documents;
  4043 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4044 with \includegraphics of LaTeX;
  4045 
  4046 * proper spacing of consecutive markup elements, especially text
  4047 blocks after section headings;
  4048 
  4049 * support bold style (for single symbols only), input syntax is like
  4050 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4051 
  4052 * \<bullet> is now output as bold \cdot by default, which looks much
  4053 better in printed text;
  4054 
  4055 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4056 note that these symbols are currently unavailable in Proof General /
  4057 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4058 
  4059 * isatool latex no longer depends on changed TEXINPUTS, instead
  4060 isatool document copies the Isabelle style files to the target
  4061 location;
  4062 
  4063 
  4064 *** Isar ***
  4065 
  4066 * Pure/Provers: improved proof by cases and induction;
  4067   - 'case' command admits impromptu naming of parameters (such as
  4068     "case (Suc n)");
  4069   - 'induct' method divinates rule instantiation from the inductive
  4070     claim; no longer requires excessive ?P bindings for proper
  4071     instantiation of cases;
  4072   - 'induct' method properly enumerates all possibilities of set/type
  4073     rules; as a consequence facts may be also passed through *type*
  4074     rules without further ado;
  4075   - 'induct' method now derives symbolic cases from the *rulified*
  4076     rule (before it used to rulify cases stemming from the internal
  4077     atomized version); this means that the context of a non-atomic
  4078     statement becomes is included in the hypothesis, avoiding the
  4079     slightly cumbersome show "PROP ?case" form;
  4080   - 'induct' may now use elim-style induction rules without chaining
  4081     facts, using ``missing'' premises from the goal state; this allows
  4082     rules stemming from inductive sets to be applied in unstructured
  4083     scripts, while still benefitting from proper handling of non-atomic
  4084     statements; NB: major inductive premises need to be put first, all
  4085     the rest of the goal is passed through the induction;
  4086   - 'induct' proper support for mutual induction involving non-atomic
  4087     rule statements (uses the new concept of simultaneous goals, see
  4088     below);
  4089   - append all possible rule selections, but only use the first
  4090     success (no backtracking);
  4091   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4092   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4093   - added 'print_induct_rules' (covered by help item in recent Proof
  4094     General versions);
  4095   - moved induct/cases attributes to Pure, methods to Provers;
  4096   - generic method setup instantiated for FOL and HOL;
  4097 
  4098 * Pure: support multiple simultaneous goal statements, for example
  4099 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4100 meta-level mechanism, this acts as if several individual goals had
  4101 been stated separately; in particular common proof methods need to be
  4102 repeated in order to cover all claims; note that a single elimination
  4103 step is *not* sufficient to establish the two conjunctions, so this
  4104 fails:
  4105 
  4106   assume "A & B" then have A and B ..   (*".." fails*)
  4107 
  4108 better use "obtain" in situations as above; alternative refer to
  4109 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4110 
  4111 * Pure: proper integration with ``locales''; unlike the original
  4112 version by Florian Kammller, Isar locales package high-level proof
  4113 contexts rather than raw logical ones (e.g. we admit to include
  4114 attributes everywhere); operations on locales include merge and
  4115 rename; support for implicit arguments (``structures''); simultaneous
  4116 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4117 some examples;
  4118 
  4119 * Pure: the following commands have been ``localized'', supporting a
  4120 target locale specification "(in name)": 'lemma', 'theorem',
  4121 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4122 stored both within the locale and at the theory level (exported and
  4123 qualified by the locale name);
  4124 
  4125 * Pure: theory goals may now be specified in ``long'' form, with
  4126 ad-hoc contexts consisting of arbitrary locale elements. for example
  4127 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4128 definitions may be given, too); the result is a meta-level rule with
  4129 the context elements being discharged in the obvious way;
  4130 
  4131 * Pure: new proof command 'using' allows to augment currently used
  4132 facts after a goal statement ('using' is syntactically analogous to
  4133 'apply', but acts on the goal's facts only); this allows chained facts
  4134 to be separated into parts given before and after a claim, as in
  4135 ``from a and b have C using d and e <proof>'';
  4136 
  4137 * Pure: renamed "antecedent" case to "rule_context";
  4138 
  4139 * Pure: new 'judgment' command records explicit information about the
  4140 object-logic embedding (used by several tools internally); no longer
  4141 use hard-wired "Trueprop";
  4142 
  4143 * Pure: added 'corollary' command;
  4144 
  4145 * Pure: fixed 'token_translation' command;
  4146 
  4147 * Pure: removed obsolete 'exported' attribute;
  4148 
  4149 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4150 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4151 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4152 
  4153 * Pure: method 'atomize' presents local goal premises as object-level
  4154 statements (atomic meta-level propositions); setup controlled via
  4155 rewrite rules declarations of 'atomize' attribute; example
  4156 application: 'induct' method with proper rule statements in improper
  4157 proof *scripts*;
  4158 
  4159 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4160 now consider the syntactic context of assumptions, giving a better
  4161 chance to get type-inference of the arguments right (this is
  4162 especially important for locales);
  4163 
  4164 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4165 mode;
  4166 
  4167 * Pure/obtain: the formal conclusion "thesis", being marked as
  4168 ``internal'', may no longer be reference directly in the text;
  4169 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4170 situations;
  4171 
  4172 * Pure: generic 'sym' attribute which declares a rule both as pure
  4173 'elim?' and for the 'symmetric' operation;
  4174 
  4175 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4176 text; the fixed correlation with particular command syntax has been
  4177 discontinued;
  4178 
  4179 * Pure: new method 'rules' is particularly well-suited for proof
  4180 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4181 but often produces more compact proof terms with less detours;
  4182 
  4183 * Pure/Provers/classical: simplified integration with pure rule
  4184 attributes and methods; the classical "intro?/elim?/dest?"
  4185 declarations coincide with the pure ones; the "rule" method no longer
  4186 includes classically swapped intros; "intro" and "elim" methods no
  4187 longer pick rules from the context; also got rid of ML declarations
  4188 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4189 INCOMPATIBILITY;
  4190 
  4191 * Provers/classical: attribute 'swapped' produces classical inversions
  4192 of introduction rules;
  4193 
  4194 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4195 rules instead of full simplifier context; 'iff' attribute handles
  4196 conditional rules;
  4197 
  4198 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4199 
  4200 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4201 "(permissive)" option to recover old behavior;
  4202 
  4203 * HOL: 'inductive' no longer features separate (collective) attributes
  4204 for 'intros' (was found too confusing);
  4205 
  4206 * HOL: properly declared induction rules less_induct and
  4207 wf_induct_rule;
  4208 
  4209 
  4210 *** HOL ***
  4211 
  4212 * HOL: moved over to sane numeral syntax; the new policy is as
  4213 follows:
  4214 
  4215   - 0 and 1 are polymorphic constants, which are defined on any
  4216   numeric type (nat, int, real etc.);
  4217 
  4218   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4219   binary representation internally;
  4220 
  4221   - type nat has special constructor Suc, and generally prefers Suc 0
  4222   over 1::nat and Suc (Suc 0) over 2::nat;
  4223 
  4224 This change may cause significant problems of INCOMPATIBILITY; here
  4225 are some hints on converting existing sources:
  4226 
  4227   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4228   entities, so expressions involving "-" (unary or binary minus) need
  4229   to be spaced properly;
  4230 
  4231   - existing occurrences of "1" may need to be constraint "1::nat" or
  4232   even replaced by Suc 0; similar for old "2";
  4233 
  4234   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4235 
  4236   - remove all special provisions on numerals in proofs;
  4237 
  4238 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4239 representation (depends on bin_arith_simps in the default context);
  4240 
  4241 * HOL: symbolic syntax for x^2 (numeral 2);
  4242 
  4243 * HOL: the class of all HOL types is now called "type" rather than
  4244 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4245 in axclass/classes, instance/arities, and (usually rare) occurrences
  4246 in typings (of consts etc.); internally the class is called
  4247 "HOL.type", ML programs should refer to HOLogic.typeS;
  4248 
  4249 * HOL/record package improvements:
  4250   - new derived operations "fields" to build a partial record section,
  4251     "extend" to promote a fixed record to a record scheme, and
  4252     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4253     declared as simp by default;
  4254   - shared operations ("more", "fields", etc.) now need to be always
  4255     qualified) --- potential INCOMPATIBILITY;
  4256   - removed "make_scheme" operations (use "make" with "extend") --
  4257     INCOMPATIBILITY;
  4258   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4259   - provides cases/induct rules for use with corresponding Isar
  4260     methods (for concrete records, record schemes, concrete more
  4261     parts, and schematic more parts -- in that order);
  4262   - internal definitions directly based on a light-weight abstract
  4263     theory of product types over typedef rather than datatype;
  4264 
  4265 * HOL: generic code generator for generating executable ML code from
  4266 specifications; specific support for HOL constructs such as inductive
  4267 datatypes and sets, as well as recursive functions; can be invoked
  4268 via 'generate_code' theory section;
  4269 
  4270 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4271 
  4272 * HOL: consolidated and renamed several theories.  In particular:
  4273         Ord.thy has been absorbed into HOL.thy
  4274         String.thy has been absorbed into List.thy
  4275 
  4276 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4277 (beware of argument permutation!);
  4278 
  4279 * HOL: linorder_less_split superseded by linorder_cases;
  4280 
  4281 * HOL/List: "nodups" renamed to "distinct";
  4282 
  4283 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4284 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4285   - Ex_def has changed, now need to use some_eq_ex
  4286 
  4287 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4288 in this (rare) case use:
  4289 
  4290   delSWrapper "split_all_tac"
  4291   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4292 
  4293 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4294 MAY FAIL;
  4295 
  4296 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4297 Isabelle's type classes, ^ on functions and relations has too general
  4298 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4299 necessary to attach explicit type constraints;
  4300 
  4301 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4302 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4303 renamed accordingly (eg "compI" -> "rel_compI").
  4304 
  4305 * HOL: syntax translations now work properly with numerals and records
  4306 expressions;
  4307 
  4308 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4309 of "lam" -- INCOMPATIBILITY;
  4310 
  4311 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4312 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4313 renamed "Product_Type.unit";
  4314 
  4315 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4316 
  4317 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4318 the "cases" method);
  4319 
  4320 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4321 Florian Kammller);
  4322 
  4323 * HOL/IMP: updated and converted to new-style theory format; several
  4324 parts turned into readable document, with proper Isar proof texts and
  4325 some explanations (by Gerwin Klein);
  4326 
  4327 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4328 
  4329 * HOL-Hyperreal is now a logic image;
  4330 
  4331 
  4332 *** HOLCF ***
  4333 
  4334 * Isar: consts/constdefs supports mixfix syntax for continuous
  4335 operations;
  4336 
  4337 * Isar: domain package adapted to new-style theory format, e.g. see
  4338 HOLCF/ex/Dnat.thy;
  4339 
  4340 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4341 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4342 lift.induct_tac, always use UU instead of Undef;
  4343 
  4344 * HOLCF/IMP: updated and converted to new-style theory;
  4345 
  4346 
  4347 *** ZF ***
  4348 
  4349 * Isar: proper integration of logic-specific tools and packages,
  4350 including theory commands '(co)inductive', '(co)datatype',
  4351 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4352 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4353 
  4354 * theory Main no longer includes AC; for the Axiom of Choice, base
  4355 your theory on Main_ZFC;
  4356 
  4357 * the integer library now covers quotients and remainders, with many
  4358 laws relating division to addition, multiplication, etc.;
  4359 
  4360 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4361 typeless version of the formalism;
  4362 
  4363 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4364 format;
  4365 
  4366 * ZF/Induct: new directory for examples of inductive definitions,
  4367 including theory Multiset for multiset orderings; converted to
  4368 new-style theory format;
  4369 
  4370 * ZF: many new theorems about lists, ordinals, etc.;
  4371 
  4372 
  4373 *** General ***
  4374 
  4375 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4376 variable proof controls level of detail: 0 = no proofs (only oracle
  4377 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4378 also ref manual for further ML interfaces;
  4379 
  4380 * Pure/axclass: removed obsolete ML interface
  4381 goal_subclass/goal_arity;
  4382 
  4383 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4384 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4385 separate tokens, so expressions involving minus need to be spaced
  4386 properly;
  4387 
  4388 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4389 rather than "infixl" or "infixr";
  4390 
  4391 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4392 sort constraint specifications in type inference; e.g. "x::_::foo"
  4393 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4394 type variable);
  4395 
  4396 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4397 control output of nested => (types); the default behavior is
  4398 "type_brackets";
  4399 
  4400 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4401 tokens into AST constants;
  4402 
  4403 * Pure/syntax: prefer later declarations of translations and print
  4404 translation functions; potential INCOMPATIBILITY: need to reverse
  4405 multiple declarations for same syntax element constant;
  4406 
  4407 * Pure/show_hyps reset by default (in accordance to existing Isar
  4408 practice);
  4409 
  4410 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4411 addSafter;
  4412 
  4413 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4414 as well;
  4415 
  4416 * system: tested support for MacOS X; should be able to get Isabelle +
  4417 Proof General to work in a plain Terminal after installing Poly/ML
  4418 (e.g. from the Isabelle distribution area) and GNU bash alone
  4419 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4420 support requires further installations, e.g. from
  4421 http://fink.sourceforge.net/);
  4422 
  4423 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4424 
  4425 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4426 of 40 MB), cf. ML_OPTIONS;
  4427 
  4428 * system: Proof General keywords specification is now part of the
  4429 Isabelle distribution (see etc/isar-keywords.el);
  4430 
  4431 * system: support for persistent Proof General sessions (refrain from
  4432 outdating all loaded theories on startup); user may create writable
  4433 logic images like this: ``isabelle -q HOL Test'';
  4434 
  4435 * system: smart selection of Isabelle process versus Isabelle
  4436 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4437 run both "isabelle" and "Isabelle" even if file names are badly
  4438 damaged (executable inspects the case of the first letter of its own
  4439 name); added separate "isabelle-process" and "isabelle-interface";
  4440 
  4441 * system: refrain from any attempt at filtering input streams; no
  4442 longer support ``8bit'' encoding of old isabelle font, instead proper
  4443 iso-latin characters may now be used; the related isatools
  4444 "symbolinput" and "nonascii" have disappeared as well;
  4445 
  4446 * system: removed old "xterm" interface (the print modes "xterm" and
  4447 "xterm_color" are still available for direct use in a suitable
  4448 terminal);
  4449 
  4450 
  4451 
  4452 New in Isabelle99-2 (February 2001)
  4453 -----------------------------------
  4454 
  4455 *** Overview of INCOMPATIBILITIES ***
  4456 
  4457 * HOL: please note that theories in the Library and elsewhere often use the
  4458 new-style (Isar) format; to refer to their theorems in an ML script you must
  4459 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4460 
  4461 * HOL: inductive package no longer splits induction rule aggressively,
  4462 but only as far as specified by the introductions given; the old
  4463 format may be recovered via ML function complete_split_rule or attribute
  4464 'split_rule (complete)';
  4465 
  4466 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4467 gfp_Tarski to gfp_unfold;
  4468 
  4469 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4470 
  4471 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4472 relation); infix "^^" has been renamed "``"; infix "``" has been
  4473 renamed "`"; "univalent" has been renamed "single_valued";
  4474 
  4475 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4476 operation;
  4477 
  4478 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4479 
  4480 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4481 
  4482 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4483 consequence, it is no longer monotonic wrt. the local goal context
  4484 (which is now passed through the inductive cases);
  4485 
  4486 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4487 \<gg> to \<ggreater>;
  4488 
  4489 
  4490 *** Document preparation ***
  4491 
  4492 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4493 available: are "it" for near math-mode best-style output, "sl" for
  4494 slanted text style, and "tt" for plain type-writer; if no
  4495 \isabellestyle command is given, output is according to slanted
  4496 type-writer);
  4497 
  4498 * support sub/super scripts (for single symbols only), input syntax is
  4499 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4500 
  4501 * some more standard symbols; see Appendix A of the system manual for
  4502 the complete list of symbols defined in isabellesym.sty;
  4503 
  4504 * improved isabelle style files; more abstract symbol implementation
  4505 (should now use \isamath{...} and \isatext{...} in custom symbol
  4506 definitions);
  4507 
  4508 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4509 state; Note that presentation of goal states does not conform to
  4510 actual human-readable proof documents.  Please do not include goal
  4511 states into document output unless you really know what you are doing!
  4512 
  4513 * proper indentation of antiquoted output with proportional LaTeX
  4514 fonts;
  4515 
  4516 * no_document ML operator temporarily disables LaTeX document
  4517 generation;
  4518 
  4519 * isatool unsymbolize tunes sources for plain ASCII communication;
  4520 
  4521 
  4522 *** Isar ***
  4523 
  4524 * Pure: Isar now suffers initial goal statements to contain unbound
  4525 schematic variables (this does not conform to actual readable proof
  4526 documents, due to unpredictable outcome and non-compositional proof
  4527 checking); users who know what they are doing may use schematic goals
  4528 for Prolog-style synthesis of proven results;
  4529 
  4530 * Pure: assumption method (an implicit finishing) now handles actual
  4531 rules as well;
  4532 
  4533 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4534 initial goal, declare "that" only as Pure intro (only for single
  4535 steps); the "that" rule assumption may now be involved in implicit
  4536 finishing, thus ".." becomes a feasible for trivial obtains;
  4537 
  4538 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4539 instance proofs may be performed by "..";
  4540 
  4541 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4542 statements as well;
  4543 
  4544 * Pure: more robust selection of calculational rules;
  4545 
  4546 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4547 rule (as well as the assumption rule);
  4548 
  4549 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4550 lemmas, using the graph browser tool;
  4551 
  4552 * Pure: predict failure of "show" in interactive mode;
  4553 
  4554 * Pure: 'thms_containing' now takes actual terms as arguments;
  4555 
  4556 * HOL: improved method 'induct' --- now handles non-atomic goals
  4557 (potential INCOMPATIBILITY); tuned error handling;
  4558 
  4559 * HOL: cases and induct rules now provide explicit hints about the
  4560 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4561 any remaining facts are inserted into the goal verbatim;
  4562 
  4563 * HOL: local contexts (aka cases) may now contain term bindings as
  4564 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4565 the result to be shown in each case;
  4566 
  4567 * HOL: added 'recdef_tc' command;
  4568 
  4569 * isatool convert assists in eliminating legacy ML scripts;
  4570 
  4571 
  4572 *** HOL ***
  4573 
  4574 * HOL/Library: a collection of generic theories to be used together
  4575 with main HOL; the theory loader path already includes this directory
  4576 by default; the following existing theories have been moved here:
  4577 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4578 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4579 
  4580 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4581 modelling and verification task performed in Isabelle/HOL +
  4582 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4583 
  4584 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4585 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4586 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4587 'domain', this makes the theory consistent with mathematical
  4588 literature;
  4589 
  4590 * HOL basics: added overloaded operations "inverse" and "divide"
  4591 (infix "/"), syntax for generic "abs" operation, generic summation
  4592 operator \<Sum>;
  4593 
  4594 * HOL/typedef: simplified package, provide more useful rules (see also
  4595 HOL/subset.thy);
  4596 
  4597 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4598 now expressed as a proper nested rule (old-style tactic scripts may
  4599 require atomize_strip_tac to cope with non-atomic premises);
  4600 
  4601 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4602 to "split_conv" (old name still available for compatibility);
  4603 
  4604 * HOL: improved concrete syntax for strings (e.g. allows translation
  4605 rules with string literals);
  4606 
  4607 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4608  and Fleuriot's mechanization of analysis, including the transcendental
  4609  functions for the reals;
  4610 
  4611 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4612 
  4613 
  4614 *** CTT ***
  4615 
  4616 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4617 "lam" is displayed as TWO lambda-symbols
  4618 
  4619 * CTT: theory Main now available, containing everything (that is, Bool
  4620 and Arith);
  4621 
  4622 
  4623 *** General ***
  4624 
  4625 * Pure: the Simplifier has been implemented properly as a derived rule
  4626 outside of the actual kernel (at last!); the overall performance
  4627 penalty in practical applications is about 50%, while reliability of
  4628 the Isabelle inference kernel has been greatly improved;
  4629 
  4630 * print modes "brackets" and "no_brackets" control output of nested =>
  4631 (types) and ==> (props); the default behaviour is "brackets";
  4632 
  4633 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4634 as assumptions as well;
  4635 
  4636 * system: support Poly/ML 4.0;
  4637 
  4638 * system: isatool install handles KDE version 1 or 2;
  4639 
  4640 
  4641 
  4642 New in Isabelle99-1 (October 2000)
  4643 ----------------------------------
  4644 
  4645 *** Overview of INCOMPATIBILITIES ***
  4646 
  4647 * HOL: simplification of natural numbers is much changed; to partly
  4648 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4649 issue the following ML commands:
  4650 
  4651   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4652   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4653 
  4654 * HOL: simplification no longer dives into case-expressions; this is
  4655 controlled by "t.weak_case_cong" for each datatype t;
  4656 
  4657 * HOL: nat_less_induct renamed to less_induct;
  4658 
  4659 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4660 fixsome to patch .thy and .ML sources automatically;
  4661 
  4662   select_equality  -> some_equality
  4663   select_eq_Ex     -> some_eq_ex
  4664   selectI2EX       -> someI2_ex
  4665   selectI2         -> someI2
  4666   selectI          -> someI
  4667   select1_equality -> some1_equality
  4668   Eps_sym_eq       -> some_sym_eq_trivial
  4669   Eps_eq           -> some_eq_trivial
  4670 
  4671 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4672 
  4673 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4674 instead);
  4675 
  4676 * HOL: the recursion equations generated by 'recdef' are now called
  4677 f.simps instead of f.rules;
  4678 
  4679 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4680 
  4681 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4682 sometimes be needed;
  4683 
  4684 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4685 
  4686 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4687 
  4688 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4689 product is now "<*>" instead of "Times"; the lexicographic product is
  4690 now "<*lex*>" instead of "**";
  4691 
  4692 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4693 of main HOL, but was unused); better use HOL's datatype package;
  4694 
  4695 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4696 the old syntax may be recovered as follows:
  4697 
  4698   syntax (symbols)
  4699     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4700       (infixl "\\<oplus>" 100)
  4701 
  4702 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4703 
  4704 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4705 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4706 internally;
  4707 
  4708 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4709 changed from A/r to A//r;
  4710 
  4711 * ZF: new treatment of arithmetic (nat & int) may break some old
  4712 proofs;
  4713 
  4714 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4715 rulify -> rule_format, elimify -> elim_format, ...);
  4716 
  4717 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4718 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4719 should have to change intro!! to intro? only); replaced "delrule" by
  4720 "rule del";
  4721 
  4722 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4723 
  4724 * Provers: strengthened force_tac by using new first_best_tac;
  4725 
  4726 * LaTeX document preparation: several changes of isabelle.sty (see
  4727 lib/texinputs);
  4728 
  4729 
  4730 *** Document preparation ***
  4731 
  4732 * formal comments (text blocks etc.) in new-style theories may now
  4733 contain antiquotations of thm/prop/term/typ/text to be presented
  4734 according to latex print mode; concrete syntax is like this:
  4735 @{term[show_types] "f(x) = a + x"};
  4736 
  4737 * isatool mkdir provides easy setup of Isabelle session directories,
  4738 including proper document sources;
  4739 
  4740 * generated LaTeX sources are now deleted after successful run
  4741 (isatool document -c); may retain a copy somewhere else via -D option
  4742 of isatool usedir;
  4743 
  4744 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4745 style files, achieving self-contained LaTeX sources and simplifying
  4746 LaTeX debugging;
  4747 
  4748 * old-style theories now produce (crude) LaTeX output as well;
  4749 
  4750 * browser info session directories are now self-contained (may be put
  4751 on WWW server seperately); improved graphs of nested sessions; removed
  4752 graph for 'all sessions';
  4753 
  4754 * several improvements in isabelle style files; \isabellestyle{it}
  4755 produces fake math mode output; \isamarkupheader is now \section by
  4756 default; see lib/texinputs/isabelle.sty etc.;
  4757 
  4758 
  4759 *** Isar ***
  4760 
  4761 * Isar/Pure: local results and corresponding term bindings are now
  4762 subject to Hindley-Milner polymorphism (similar to ML); this
  4763 accommodates incremental type-inference very nicely;
  4764 
  4765 * Isar/Pure: new derived language element 'obtain' supports
  4766 generalized existence reasoning;
  4767 
  4768 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4769 support accumulation of results, without applying any rules yet;
  4770 useful to collect intermediate results without explicit name
  4771 references, and for use with transitivity rules with more than 2
  4772 premises;
  4773 
  4774 * Isar/Pure: scalable support for case-analysis type proofs: new
  4775 'case' language element refers to local contexts symbolically, as
  4776 produced by certain proof methods; internally, case names are attached
  4777 to theorems as "tags";
  4778 
  4779 * Isar/Pure: theory command 'hide' removes declarations from
  4780 class/type/const name spaces;
  4781 
  4782 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4783 indicate potential overloading;
  4784 
  4785 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4786 
  4787 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4788 "{a,b,c}" instead of {a,b,c};
  4789 
  4790 * Isar/Pure now provides its own version of intro/elim/dest
  4791 attributes; useful for building new logics, but beware of confusion
  4792 with the version in Provers/classical;
  4793 
  4794 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4795 case name 'antecedent';
  4796 
  4797 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4798 to the current context is now done automatically);
  4799 
  4800 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4801 for definining proof methods in ML;
  4802 
  4803 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4804 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4805 most cases, one should have to change intro!! to intro? only);
  4806 replaced "delrule" by "rule del";
  4807 
  4808 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4809 'symmetric' attribute (the latter supercedes [RS sym]);
  4810 
  4811 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4812 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4813 well (including splits);
  4814 
  4815 * Isar/Provers: Simplifier and Classical methods now support all kind
  4816 of modifiers used in the past, including 'cong', 'iff', etc.
  4817 
  4818 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4819 of Simplifier and Classical reasoner);
  4820 
  4821 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4822 now support named cases; major packages (inductive, datatype, primrec,
  4823 recdef) support case names and properly name parameters;
  4824 
  4825 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4826 monotonicity conditions are extracted to be proven at end of
  4827 calculations;
  4828 
  4829 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4830 method anyway;
  4831 
  4832 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4833 split_if split_if_asm; datatype package provides theorems foo.splits =
  4834 foo.split foo.split_asm for each datatype;
  4835 
  4836 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4837 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4838 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4839 use "(cases (simplified))" method in proper proof texts);
  4840 
  4841 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4842 
  4843 * Isar: names of theorems etc. may be natural numbers as well;
  4844 
  4845 * Isar: 'pr' command: optional arguments for goals_limit and
  4846 ProofContext.prems_limit; no longer prints theory contexts, but only
  4847 proof states;
  4848 
  4849 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4850 additional print modes to be specified; e.g. "pr(latex)" will print
  4851 proof state according to the Isabelle LaTeX style;
  4852 
  4853 * Isar: improved support for emulating tactic scripts, including proof
  4854 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4855 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4856 (for HOL datatypes);
  4857 
  4858 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4859 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4860 'proof method scripts' have to be in depth-first order;
  4861 
  4862 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4863 
  4864 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4865 should instead use individual commands for printing items
  4866 (print_commands, print_methods etc.);
  4867 
  4868 * Isar: added 'nothing' --- the empty list of theorems;
  4869 
  4870 
  4871 *** HOL ***
  4872 
  4873 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4874 corresponding virtual machine and a specification of its bytecode
  4875 verifier and a lightweight bytecode verifier, including proofs of
  4876 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4877 Cornelia Pusch (see also the homepage of project Bali at
  4878 http://isabelle.in.tum.de/Bali/);
  4879 
  4880 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4881 Clemens Ballarin;
  4882 
  4883 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4884 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4885 Rasmussen;
  4886 
  4887 * HOL/Lattice: fundamental concepts of lattice theory and order
  4888 structures, including duals, properties of bounds versus algebraic
  4889 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4890 Theorem for complete lattices etc.; may also serve as a demonstration
  4891 for abstract algebraic reasoning using axiomatic type classes, and
  4892 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4893 
  4894 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4895 von Oheimb;
  4896 
  4897 * HOL/IMPP: extension of IMP with local variables and mutually
  4898 recursive procedures, by David von Oheimb;
  4899 
  4900 * HOL/Lambda: converted into new-style theory and document;
  4901 
  4902 * HOL/ex/Multiquote: example of multiple nested quotations and
  4903 anti-quotations -- basically a generalized version of de-Bruijn
  4904 representation; very useful in avoiding lifting of operations;
  4905 
  4906 * HOL/record: added general record equality rule to simpset; fixed
  4907 select-update simplification procedure to handle extended records as
  4908 well; admit "r" as field name;
  4909 
  4910 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4911 other numeric types and also as the identity of groups, rings, etc.;
  4912 
  4913 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4914 Types nat and int belong to this axclass;
  4915 
  4916 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4917    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4918    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4919   two terms #m*u and #n*u are replaced by #(m+n)*u
  4920     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4921   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4922     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4923 
  4924 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4925 powerful prover for predicate logic but knows nothing of clasets; see
  4926 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4927 
  4928 * HOL: new version of "case_tac" subsumes both boolean case split and
  4929 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4930 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4931 
  4932 * HOL: simplification no longer dives into case-expressions: only the
  4933 selector expression is simplified, but not the remaining arms; to
  4934 enable full simplification of case-expressions for datatype t, you may
  4935 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4936 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4937 
  4938 * HOL/recdef: the recursion equations generated by 'recdef' for
  4939 function 'f' are now called f.simps instead of f.rules; if all
  4940 termination conditions are proved automatically, these simplification
  4941 rules are added to the simpset, as in primrec; rules may be named
  4942 individually as well, resulting in a separate list of theorems for
  4943 each equation;
  4944 
  4945 * HOL/While is a new theory that provides a while-combinator. It
  4946 permits the definition of tail-recursive functions without the
  4947 provision of a termination measure. The latter is necessary once the
  4948 invariant proof rule for while is applied.
  4949 
  4950 * HOL: new (overloaded) notation for the set of elements below/above
  4951 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4952 
  4953 * HOL: theorems impI, allI, ballI bound as "strip";
  4954 
  4955 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4956 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4957 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4958 
  4959 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4960 
  4961 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4962 main HOL, but was unused);
  4963 
  4964 * HOL: fewer consts declared as global (e.g. have to refer to
  4965 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4966 
  4967 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4968 in case of overlap with user translations (e.g. judgements over
  4969 tuples); (note that the underlying logical represenation is still
  4970 bogus);
  4971 
  4972 
  4973 *** ZF ***
  4974 
  4975 * ZF: simplification automatically cancels common terms in arithmetic
  4976 expressions over nat and int;
  4977 
  4978 * ZF: new treatment of nat to minimize type-checking: all operators
  4979 coerce their operands to a natural number using the function natify,
  4980 making the algebraic laws unconditional;
  4981 
  4982 * ZF: as above, for int: operators coerce their operands to an integer
  4983 using the function intify;
  4984 
  4985 * ZF: the integer library now contains many of the usual laws for the
  4986 orderings, including $<=, and monotonicity laws for $+ and $*;
  4987 
  4988 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4989 simplification;
  4990 
  4991 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4992 to the simplifier and classical reasoner simultaneously;
  4993 
  4994 
  4995 *** General ***
  4996 
  4997 * Provers: blast_tac now handles actual object-logic rules as
  4998 assumptions; note that auto_tac uses blast_tac internally as well;
  4999 
  5000 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5001 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5002 
  5003 * Provers: delrules now handles destruct rules as well (no longer need
  5004 explicit make_elim);
  5005 
  5006 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5007   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5008 use instead the strong form,
  5009   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5010 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5011 from destruct-rules;
  5012 
  5013 * Provers: Simplifier.easy_setup provides a fast path to basic
  5014 Simplifier setup for new object-logics;
  5015 
  5016 * Pure: AST translation rules no longer require constant head on LHS;
  5017 
  5018 * Pure: improved name spaces: ambiguous output is qualified; support
  5019 for hiding of names;
  5020 
  5021 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5022 XSYMBOL_HOME; no longer need to do manual configuration in most
  5023 situations;
  5024 
  5025 * system: compression of ML heaps images may now be controlled via -c
  5026 option of isabelle and isatool usedir (currently only observed by
  5027 Poly/ML);
  5028 
  5029 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5030 useful for remote X11);
  5031 
  5032 * system: provide TAGS file for Isabelle sources;
  5033 
  5034 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5035 order;
  5036 
  5037 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5038 timing flag supersedes proof_timing and Toplevel.trace;
  5039 
  5040 * ML: new combinators |>> and |>>> for incremental transformations
  5041 with secondary results (e.g. certain theory extensions):
  5042 
  5043 * ML: PureThy.add_defs gets additional argument to indicate potential
  5044 overloading (usually false);
  5045 
  5046 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5047 results;
  5048 
  5049 
  5050 
  5051 New in Isabelle99 (October 1999)
  5052 --------------------------------
  5053 
  5054 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5055 
  5056 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5057 are no longer simplified.  (This allows the simplifier to unfold recursive
  5058 functional programs.)  To restore the old behaviour, declare
  5059 
  5060     Delcongs [if_weak_cong];
  5061 
  5062 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5063 complement;
  5064 
  5065 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5066 
  5067 * HOL/datatype: mutual_induct_tac no longer exists --
  5068   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5069 
  5070 * HOL/typedef: fixed type inference for representing set; type
  5071 arguments now have to occur explicitly on the rhs as type constraints;
  5072 
  5073 * ZF: The con_defs part of an inductive definition may no longer refer
  5074 to constants declared in the same theory;
  5075 
  5076 * HOL, ZF: the function mk_cases, generated by the inductive
  5077 definition package, has lost an argument.  To simplify its result, it
  5078 uses the default simpset instead of a supplied list of theorems.
  5079 
  5080 * HOL/List: the constructors of type list are now Nil and Cons;
  5081 
  5082 * Simplifier: the type of the infix ML functions
  5083         setSSolver addSSolver setSolver addSolver
  5084 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5085 for packaging solvers. A solver is created via
  5086         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5087 where the string argument is only a comment.
  5088 
  5089 
  5090 *** Proof tools ***
  5091 
  5092 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5093 decision procedure for linear arithmetic. Currently it is used for
  5094 types `nat', `int', and `real' in HOL (see below); it can, should and
  5095 will be instantiated for other types and logics as well.
  5096 
  5097 * The simplifier now accepts rewrite rules with flexible heads, eg
  5098      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5099   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5100   matching.
  5101 
  5102 
  5103 *** General ***
  5104 
  5105 * New Isabelle/Isar subsystem provides an alternative to traditional
  5106 tactical theorem proving; together with the ProofGeneral/isar user
  5107 interface it offers an interactive environment for developing human
  5108 readable proof documents (Isar == Intelligible semi-automated
  5109 reasoning); for further information see isatool doc isar-ref,
  5110 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5111 
  5112 * improved and simplified presentation of theories: better HTML markup
  5113 (including colors), graph views in several sizes; isatool usedir now
  5114 provides a proper interface for user theories (via -P option); actual
  5115 document preparation based on (PDF)LaTeX is available as well (for
  5116 new-style theories only); see isatool doc system for more information;
  5117 
  5118 * native support for Proof General, both for classic Isabelle and
  5119 Isabelle/Isar;
  5120 
  5121 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5122 using the graph browser tool;
  5123 
  5124 * Isabelle manuals now also available as PDF;
  5125 
  5126 * theory loader rewritten from scratch (may not be fully
  5127 bug-compatible); old loadpath variable has been replaced by show_path,
  5128 add_path, del_path, reset_path functions; new operations such as
  5129 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5130 isatool doc ref);
  5131 
  5132 * improved isatool install: option -k creates KDE application icon,
  5133 option -p DIR installs standalone binaries;
  5134 
  5135 * added ML_PLATFORM setting (useful for cross-platform installations);
  5136 more robust handling of platform specific ML images for SML/NJ;
  5137 
  5138 * the settings environment is now statically scoped, i.e. it is never
  5139 created again in sub-processes invoked from isabelle, isatool, or
  5140 Isabelle;
  5141 
  5142 * path element specification '~~' refers to '$ISABELLE_HOME';
  5143 
  5144 * in locales, the "assumes" and "defines" parts may be omitted if
  5145 empty;
  5146 
  5147 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5148 long arrows);
  5149 
  5150 * new print_mode "HTML";
  5151 
  5152 * new flag show_tags controls display of tags of theorems (which are
  5153 basically just comments that may be attached by some tools);
  5154 
  5155 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5156 mode and goal output format:
  5157 
  5158 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5159 244c244
  5160 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5161 ---
  5162 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5163 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5164 181c181
  5165 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5166 ---
  5167 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5168 
  5169 * function bind_thms stores lists of theorems (cf. bind_thm);
  5170 
  5171 * new shorthand tactics ftac, eatac, datac, fatac;
  5172 
  5173 * qed (and friends) now accept "" as result name; in that case the
  5174 theorem is not stored, but proper checks and presentation of the
  5175 result still apply;
  5176 
  5177 * theorem database now also indexes constants "Trueprop", "all",
  5178 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5179 
  5180 
  5181 *** HOL ***
  5182 
  5183 ** HOL arithmetic **
  5184 
  5185 * There are now decision procedures for linear arithmetic over nat and
  5186 int:
  5187 
  5188 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5189 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5190 are treated as atomic; subformulae not involving type `nat' or `int'
  5191 are ignored; quantified subformulae are ignored unless they are
  5192 positive universal or negative existential. The tactic has to be
  5193 invoked by hand and can be a little bit slow. In particular, the
  5194 running time is exponential in the number of occurrences of `min' and
  5195 `max', and `-' on `nat'.
  5196 
  5197 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5198 (negated) (in)equalities among the premises and the conclusion into
  5199 account (i.e. no compound formulae) and does not know about `min' and
  5200 `max', and `-' on `nat'. It is fast and is used automatically by the
  5201 simplifier.
  5202 
  5203 NB: At the moment, these decision procedures do not cope with mixed
  5204 nat/int formulae where the two parts interact, such as `m < n ==>
  5205 int(m) < int(n)'.
  5206 
  5207 * HOL/Numeral provides a generic theory of numerals (encoded
  5208 efficiently as bit strings); setup for types nat/int/real is in place;
  5209 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5210 int, existing theories and proof scripts may require a few additional
  5211 type constraints;
  5212 
  5213 * integer division and remainder can now be performed on constant
  5214 arguments;
  5215 
  5216 * many properties of integer multiplication, division and remainder
  5217 are now available;
  5218 
  5219 * An interface to the Stanford Validity Checker (SVC) is available through the
  5220 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5221 are proved automatically.  SVC must be installed separately, and its results
  5222 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5223 invocation of the underlying oracle).  For SVC see
  5224   http://verify.stanford.edu/SVC
  5225 
  5226 * IsaMakefile: the HOL-Real target now builds an actual image;
  5227 
  5228 
  5229 ** HOL misc **
  5230 
  5231 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5232 (in Isabelle/Isar) -- by Gertrud Bauer;
  5233 
  5234 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5235 analysis for assembly languages with subtypes;
  5236 
  5237 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5238 -- avoids syntactic ambiguities and treats state, transition, and
  5239 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5240 changed syntax and (many) tactics;
  5241 
  5242 * HOL/inductive: Now also handles more general introduction rules such
  5243   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5244   theorems are now maintained within the theory (maintained via the
  5245   "mono" attribute);
  5246 
  5247 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5248   (using function types) such as
  5249 
  5250   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5251 
  5252 * HOL/record: record_simproc (part of the default simpset) takes care
  5253 of selectors applied to updated records; record_split_tac is no longer
  5254 part of the default claset; update_defs may now be removed from the
  5255 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5256 
  5257   claset_ref () := claset() addSWrapper record_split_wrapper;
  5258   Delsimprocs [record_simproc]
  5259 
  5260 * HOL/typedef: fixed type inference for representing set; type
  5261 arguments now have to occur explicitly on the rhs as type constraints;
  5262 
  5263 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5264 names rather than an ML expression;
  5265 
  5266 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5267 supplied later.  Program schemes can be defined, such as
  5268     "While B C s = (if B s then While B C (C s) else s)"
  5269 where the well-founded relation can be chosen after B and C have been given.
  5270 
  5271 * HOL/List: the constructors of type list are now Nil and Cons;
  5272 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5273 course, ML tools referring to List.list.op # etc. have to be adapted;
  5274 
  5275 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5276 disabled by default; run isabelle with option -m HOL to get back to
  5277 the original Gordon/HOL-style output;
  5278 
  5279 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5280 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5281 
  5282 * HOL basic syntax simplified (more orthogonal): all variants of
  5283 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5284 Eps operator is provided as well: "SOME x. P[x]";
  5285 
  5286 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5287 
  5288 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5289 thus available for user theories;
  5290 
  5291 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5292 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5293 time;
  5294 
  5295 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5296 several times and then mp;
  5297 
  5298 
  5299 *** LK ***
  5300 
  5301 * the notation <<...>> is now available as a notation for sequences of
  5302 formulas;
  5303 
  5304 * the simplifier is now installed
  5305 
  5306 * the axiom system has been generalized (thanks to Soren Heilmann)
  5307 
  5308 * the classical reasoner now has a default rule database
  5309 
  5310 
  5311 *** ZF ***
  5312 
  5313 * new primrec section allows primitive recursive functions to be given
  5314 directly (as in HOL) over datatypes and the natural numbers;
  5315 
  5316 * new tactics induct_tac and exhaust_tac for induction (or case
  5317 analysis) over datatypes and the natural numbers;
  5318 
  5319 * the datatype declaration of type T now defines the recursor T_rec;
  5320 
  5321 * simplification automatically does freeness reasoning for datatype
  5322 constructors;
  5323 
  5324 * automatic type-inference, with AddTCs command to insert new
  5325 type-checking rules;
  5326 
  5327 * datatype introduction rules are now added as Safe Introduction rules
  5328 to the claset;
  5329 
  5330 * the syntax "if P then x else y" is now available in addition to
  5331 if(P,x,y);
  5332 
  5333 
  5334 *** Internal programming interfaces ***
  5335 
  5336 * tuned simplifier trace output; new flag debug_simp;
  5337 
  5338 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5339 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5340 
  5341 * AxClass.axclass_tac lost the theory argument;
  5342 
  5343 * tuned current_goals_markers semantics: begin / end goal avoids
  5344 printing empty lines;
  5345 
  5346 * removed prs and prs_fn hook, which was broken because it did not
  5347 include \n in its semantics, forcing writeln to add one
  5348 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5349 string -> unit if you really want to output text without newline;
  5350 
  5351 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5352 plain output, interface builders may have to enable 'isabelle_font'
  5353 mode to get Isabelle font glyphs as before;
  5354 
  5355 * refined token_translation interface; INCOMPATIBILITY: output length
  5356 now of type real instead of int;
  5357 
  5358 * theory loader actions may be traced via new ThyInfo.add_hook
  5359 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5360 your own database of information attached to *whole* theories -- as
  5361 opposed to intra-theory data slots offered via TheoryDataFun;
  5362 
  5363 * proper handling of dangling sort hypotheses (at last!);
  5364 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5365 extra sort hypotheses that can be witnessed from the type signature;
  5366 the force_strip_shyps flag is gone, any remaining shyps are simply
  5367 left in the theorem (with a warning issued by strip_shyps_warning);
  5368 
  5369 
  5370 
  5371 New in Isabelle98-1 (October 1998)
  5372 ----------------------------------
  5373 
  5374 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5375 
  5376 * several changes of automated proof tools;
  5377 
  5378 * HOL: major changes to the inductive and datatype packages, including
  5379 some minor incompatibilities of theory syntax;
  5380 
  5381 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5382 called `inj_on';
  5383 
  5384 * HOL: removed duplicate thms in Arith:
  5385   less_imp_add_less  should be replaced by  trans_less_add1
  5386   le_imp_add_le      should be replaced by  trans_le_add1
  5387 
  5388 * HOL: unary minus is now overloaded (new type constraints may be
  5389 required);
  5390 
  5391 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5392 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5393 now taken as an integer constant.
  5394 
  5395 * Pure: ML function 'theory_of' renamed to 'theory';
  5396 
  5397 
  5398 *** Proof tools ***
  5399 
  5400 * Simplifier:
  5401   1. Asm_full_simp_tac is now more aggressive.
  5402      1. It will sometimes reorient premises if that increases their power to
  5403         simplify.
  5404      2. It does no longer proceed strictly from left to right but may also
  5405         rotate premises to achieve further simplification.
  5406      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5407      old Asm_full_simp_tac in that it does not rotate premises.
  5408   2. The simplifier now knows a little bit about nat-arithmetic.
  5409 
  5410 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5411 allows for selected deletion of wrappers, by introduction of names for
  5412 wrapper functionals.  This implies that addbefore, addSbefore,
  5413 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5414 and that adding two tactics with the same name overwrites the first
  5415 one (emitting a warning).
  5416   type wrapper = (int -> tactic) -> (int -> tactic)
  5417   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5418   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5419   delWrapper, delSWrapper: claset *  string            -> claset
  5420   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5421 
  5422 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5423 semantics; addbefore now affects only the unsafe part of step_tac
  5424 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5425 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5426 by Force_tac;
  5427 
  5428 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5429 compWrapper; added safe wrapper (and access functions for it);
  5430 
  5431 * HOL/split_all_tac is now much faster and fails if there is nothing
  5432 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5433 and the names of the automatically generated variables have changed.
  5434 split_all_tac has moved within claset() from unsafe wrappers to safe
  5435 wrappers, which means that !!-bound variables are split much more
  5436 aggressively, and safe_tac and clarify_tac now split such variables.
  5437 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5438 Note: the same holds for record_split_tac, which does the job of
  5439 split_all_tac for record fields.
  5440 
  5441 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5442 permanently to the default simpset using Addsplits just like
  5443 Addsimps. They can be removed via Delsplits just like
  5444 Delsimps. Lower-case versions are also available.
  5445 
  5446 * HOL/Simplifier: The rule split_if is now part of the default
  5447 simpset. This means that the simplifier will eliminate all occurrences
  5448 of if-then-else in the conclusion of a goal. To prevent this, you can
  5449 either remove split_if completely from the default simpset by
  5450 `Delsplits [split_if]' or remove it in a specific call of the
  5451 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5452 other case splitting rules to/from the default simpset: every datatype
  5453 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5454 t is the name of the datatype).
  5455 
  5456 * Classical reasoner / Simplifier combination: new force_tac (and
  5457 derivatives Force_tac, force) combines rewriting and classical
  5458 reasoning (and whatever other tools) similarly to auto_tac, but is
  5459 aimed to solve the given subgoal completely.
  5460 
  5461 
  5462 *** General ***
  5463 
  5464 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5465 and `goalw': the theory is no longer needed as an explicit argument -
  5466 the current theory context is used; assumptions are no longer returned
  5467 at the ML-level unless one of them starts with ==> or !!; it is
  5468 recommended to convert to these new commands using isatool fixgoal
  5469 (backup your sources first!);
  5470 
  5471 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5472 the current theory context, and 'theory' to lookup stored theories;
  5473 
  5474 * new theory section 'locale' for declaring constants, assumptions and
  5475 definitions that have local scope;
  5476 
  5477 * new theory section 'nonterminals' for purely syntactic types;
  5478 
  5479 * new theory section 'setup' for generic ML setup functions
  5480 (e.g. package initialization);
  5481 
  5482 * the distribution now includes Isabelle icons: see
  5483 lib/logo/isabelle-{small,tiny}.xpm;
  5484 
  5485 * isatool install - install binaries with absolute references to
  5486 ISABELLE_HOME/bin;
  5487 
  5488 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5489 
  5490 * print mode 'emacs' reserved for Isamode;
  5491 
  5492 * support multiple print (ast) translations per constant name;
  5493 
  5494 * theorems involving oracles are now printed with a suffixed [!];
  5495 
  5496 
  5497 *** HOL ***
  5498 
  5499 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5500 
  5501 * HOL/inductive package reorganized and improved: now supports mutual
  5502 definitions such as
  5503 
  5504   inductive EVEN ODD
  5505     intrs
  5506       null "0 : EVEN"
  5507       oddI "n : EVEN ==> Suc n : ODD"
  5508       evenI "n : ODD ==> Suc n : EVEN"
  5509 
  5510 new theorem list "elims" contains an elimination rule for each of the
  5511 recursive sets; inductive definitions now handle disjunctive premises
  5512 correctly (also ZF);
  5513 
  5514 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5515 "mutual_induct" no longer exists - the induction rule is always
  5516 contained in "induct";
  5517 
  5518 
  5519 * HOL/datatype package re-implemented and greatly improved: now
  5520 supports mutually recursive datatypes such as
  5521 
  5522   datatype
  5523     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5524             | SUM ('a aexp) ('a aexp)
  5525             | DIFF ('a aexp) ('a aexp)
  5526             | NUM 'a
  5527   and
  5528     'a bexp = LESS ('a aexp) ('a aexp)
  5529             | AND ('a bexp) ('a bexp)
  5530             | OR ('a bexp) ('a bexp)
  5531 
  5532 as well as indirectly recursive datatypes such as
  5533 
  5534   datatype
  5535     ('a, 'b) term = Var 'a
  5536                   | App 'b ((('a, 'b) term) list)
  5537 
  5538 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5539 induction on mutually / indirectly recursive datatypes.
  5540 
  5541 Primrec equations are now stored in theory and can be accessed via
  5542 <function_name>.simps.
  5543 
  5544 INCOMPATIBILITIES:
  5545 
  5546   - Theories using datatypes must now have theory Datatype as an
  5547     ancestor.
  5548   - The specific <typename>.induct_tac no longer exists - use the
  5549     generic induct_tac instead.
  5550   - natE has been renamed to nat.exhaust - use exhaust_tac
  5551     instead of res_inst_tac ... natE. Note that the variable
  5552     names in nat.exhaust differ from the names in natE, this
  5553     may cause some "fragile" proofs to fail.
  5554   - The theorems split_<typename>_case and split_<typename>_case_asm
  5555     have been renamed to <typename>.split and <typename>.split_asm.
  5556   - Since default sorts of type variables are now handled correctly,
  5557     some datatype definitions may have to be annotated with explicit
  5558     sort constraints.
  5559   - Primrec definitions no longer require function name and type
  5560     of recursive argument.
  5561 
  5562 Consider using isatool fixdatatype to adapt your theories and proof
  5563 scripts to the new package (backup your sources first!).
  5564 
  5565 
  5566 * HOL/record package: considerably improved implementation; now
  5567 includes concrete syntax for record types, terms, updates; theorems
  5568 for surjective pairing and splitting !!-bound record variables; proof
  5569 support is as follows:
  5570 
  5571   1) standard conversions (selectors or updates applied to record
  5572 constructor terms) are part of the standard simpset;
  5573 
  5574   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5575 made part of standard simpset and claset via addIffs;
  5576 
  5577   3) a tactic for record field splitting (record_split_tac) is part of
  5578 the standard claset (addSWrapper);
  5579 
  5580 To get a better idea about these rules you may retrieve them via
  5581 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5582 the name of your record type.
  5583 
  5584 The split tactic 3) conceptually simplifies by the following rule:
  5585 
  5586   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5587 
  5588 Thus any record variable that is bound by meta-all will automatically
  5589 blow up into some record constructor term, consequently the
  5590 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5591 solve record problems automatically.
  5592 
  5593 
  5594 * reorganized the main HOL image: HOL/Integ and String loaded by
  5595 default; theory Main includes everything;
  5596 
  5597 * automatic simplification of integer sums and comparisons, using cancellation;
  5598 
  5599 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5600 
  5601 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5602 
  5603 * many new identities for unions, intersections, set difference, etc.;
  5604 
  5605 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5606 called split_if, split_split, split_sum_case and split_nat_case (to go
  5607 with add/delsplits);
  5608 
  5609 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5610 (?x::unit) = (); this is made part of the default simpset, which COULD
  5611 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5612 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5613 unit_abs_eta_conv is added in order to counter the effect of
  5614 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5615 %u.f();
  5616 
  5617 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5618 makes more sense);
  5619 
  5620 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5621   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5622   disjointness reasoning but breaking a few old proofs.
  5623 
  5624 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5625 to 'converse' from 'inverse' (for compatibility with ZF and some
  5626 literature);
  5627 
  5628 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5629 the well-founded relation;
  5630 
  5631 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5632     Compl A.  The "Compl" syntax remains available as input syntax for this
  5633     release ONLY.
  5634 
  5635 * HOL/Update: new theory of function updates:
  5636     f(a:=b) == %x. if x=a then b else f x
  5637 may also be iterated as in f(a:=b,c:=d,...);
  5638 
  5639 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5640 
  5641 * HOL/List:
  5642   - new function list_update written xs[i:=v] that updates the i-th
  5643     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5644   - new function `upt' written [i..j(] which generates the list
  5645     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5646     bound write [i..j], which is a shorthand for [i..j+1(].
  5647   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5648 
  5649 * HOL/Arith:
  5650   - removed 'pred' (predecessor) function;
  5651   - generalized some theorems about n-1;
  5652   - many new laws about "div" and "mod";
  5653   - new laws about greatest common divisors (see theory ex/Primes);
  5654 
  5655 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5656 instead of "inverse";
  5657 
  5658 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5659   of the multiset ordering;
  5660 
  5661 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5662   (not included by default);
  5663 
  5664 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5665 
  5666 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5667   programs, i.e. different program variables may have different types.
  5668 
  5669 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5670   [previously, this check worked only if the rewrite rule was unconditional]
  5671   Now rew can involve either definitions or equalities (either == or =).
  5672 
  5673 
  5674 *** ZF ***
  5675 
  5676 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5677   only the theorems proved on ZF.ML;
  5678 
  5679 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5680   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5681   disjointness reasoning but breaking a few old proofs.
  5682 
  5683 * ZF/Update: new theory of function updates
  5684     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5685   may also be iterated as in f(a:=b,c:=d,...);
  5686 
  5687 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5688 
  5689 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5690   [previously, this check worked only if the rewrite rule was unconditional]
  5691   Now rew can involve either definitions or equalities (either == or =).
  5692 
  5693 * case_tac provided for compatibility with HOL
  5694     (like the old excluded_middle_tac, but with subgoals swapped)
  5695 
  5696 
  5697 *** Internal programming interfaces ***
  5698 
  5699 * Pure: several new basic modules made available for general use, see
  5700 also src/Pure/README;
  5701 
  5702 * improved the theory data mechanism to support encapsulation (data
  5703 kind name replaced by private Object.kind, acting as authorization
  5704 key); new type-safe user interface via functor TheoryDataFun; generic
  5705 print_data function becomes basically useless;
  5706 
  5707 * removed global_names compatibility flag -- all theory declarations
  5708 are qualified by default;
  5709 
  5710 * module Pure/Syntax now offers quote / antiquote translation
  5711 functions (useful for Hoare logic etc. with implicit dependencies);
  5712 see HOL/ex/Antiquote for an example use;
  5713 
  5714 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5715 cterm -> thm;
  5716 
  5717 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5718 subgoal;
  5719 
  5720 * Display.print_goals function moved to Locale.print_goals;
  5721 
  5722 * standard print function for goals supports current_goals_markers
  5723 variable for marking begin of proof, end of proof, start of goal; the
  5724 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5725 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5726 for example;
  5727 
  5728 
  5729 
  5730 New in Isabelle98 (January 1998)
  5731 --------------------------------
  5732 
  5733 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5734 
  5735 * changed lexical syntax of terms / types: dots made part of long
  5736 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5737 
  5738 * simpset (and claset) reference variable replaced by functions
  5739 simpset / simpset_ref;
  5740 
  5741 * no longer supports theory aliases (via merge) and non-trivial
  5742 implicit merge of thms' signatures;
  5743 
  5744 * most internal names of constants changed due to qualified names;
  5745 
  5746 * changed Pure/Sequence interface (see Pure/seq.ML);
  5747 
  5748 
  5749 *** General Changes ***
  5750 
  5751 * hierachically structured name spaces (for consts, types, axms, thms
  5752 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5753 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5754 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5755 long_names for fully qualified output names; NOTE: ML programs
  5756 (special tactics, packages etc.) referring to internal names may have
  5757 to be adapted to cope with fully qualified names; in case of severe
  5758 backward campatibility problems try setting 'global_names' at compile
  5759 time to have enrything declared within a flat name space; one may also
  5760 fine tune name declarations in theories via the 'global' and 'local'
  5761 section;
  5762 
  5763 * reimplemented the implicit simpset and claset using the new anytype
  5764 data filed in signatures; references simpset:simpset ref etc. are
  5765 replaced by functions simpset:unit->simpset and
  5766 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5767 to patch your ML files accordingly;
  5768 
  5769 * HTML output now includes theory graph data for display with Java
  5770 applet or isatool browser; data generated automatically via isatool
  5771 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5772 
  5773 * defs may now be conditional; improved rewrite_goals_tac to handle
  5774 conditional equations;
  5775 
  5776 * defs now admits additional type arguments, using TYPE('a) syntax;
  5777 
  5778 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5779 creates a new theory node; implicit merge of thms' signatures is
  5780 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5781 transfer:theory->thm->thm in (rare) cases;
  5782 
  5783 * improved handling of draft signatures / theories; draft thms (and
  5784 ctyps, cterms) are automatically promoted to real ones;
  5785 
  5786 * slightly changed interfaces for oracles: admit many per theory, named
  5787 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5788 
  5789 * print_goals: optional output of const types (set show_consts and
  5790 show_types);
  5791 
  5792 * improved output of warnings (###) and errors (***);
  5793 
  5794 * subgoal_tac displays a warning if the new subgoal has type variables;
  5795 
  5796 * removed old README and Makefiles;
  5797 
  5798 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5799 
  5800 * removed obsolete init_pps and init_database;
  5801 
  5802 * deleted the obsolete tactical STATE, which was declared by
  5803     fun STATE tacfun st = tacfun st st;
  5804 
  5805 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5806 (which abbreviates $HOME);
  5807 
  5808 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5809 use isatool fixseq to adapt your ML programs (this works for fully
  5810 qualified references to the Sequence structure only!);
  5811 
  5812 * use_thy no longer requires writable current directory; it always
  5813 reloads .ML *and* .thy file, if either one is out of date;
  5814 
  5815 
  5816 *** Classical Reasoner ***
  5817 
  5818 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5819 tactics that use classical reasoning to simplify a subgoal without
  5820 splitting it into several subgoals;
  5821 
  5822 * Safe_tac: like safe_tac but uses the default claset;
  5823 
  5824 
  5825 *** Simplifier ***
  5826 
  5827 * added simplification meta rules:
  5828     (asm_)(full_)simplify: simpset -> thm -> thm;
  5829 
  5830 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5831 logics (again);
  5832 
  5833 * added prems argument to simplification procedures;
  5834 
  5835 * HOL, FOL, ZF: added infix function `addsplits':
  5836   instead of `<simpset> setloop (split_tac <thms>)'
  5837   you can simply write `<simpset> addsplits <thms>'
  5838 
  5839 
  5840 *** Syntax ***
  5841 
  5842 * TYPE('a) syntax for type reflection terms;
  5843 
  5844 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5845 
  5846 * pretty printer: changed order of mixfix annotation preference (again!);
  5847 
  5848 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5849 
  5850 
  5851 *** HOL ***
  5852 
  5853 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5854   with `addloop' of the simplifier to faciliate case splitting in premises.
  5855 
  5856 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5857 
  5858 * HOL/Auth: new protocol proofs including some for the Internet
  5859   protocol TLS;
  5860 
  5861 * HOL/Map: new theory of `maps' a la VDM;
  5862 
  5863 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5864 cancelling out common nat summands from =, <, <= (in)equalities, or
  5865 differences; simplification procedures nat_cancel_factor for
  5866 cancelling common factor from =, <, <= (in)equalities over natural
  5867 sums; nat_cancel contains both kinds of procedures, it is installed by
  5868 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5869 
  5870 * HOL/simplifier: terms of the form
  5871   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5872   are rewritten to
  5873   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5874   and those of the form
  5875   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5876   are rewritten to
  5877   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5878 
  5879 * HOL/datatype
  5880   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5881 
  5882   P(t_case f1 ... fn x) =
  5883      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5884         ...
  5885        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5886      )
  5887 
  5888   and a theorem `split_t_case_asm' of the form
  5889 
  5890   P(t_case f1 ... fn x) =
  5891     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5892         ...
  5893        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5894      )
  5895   which can be added to a simpset via `addsplits'. The existing theorems
  5896   expand_list_case and expand_option_case have been renamed to
  5897   split_list_case and split_option_case.
  5898 
  5899 * HOL/Arithmetic:
  5900   - `pred n' is automatically converted to `n-1'.
  5901     Users are strongly encouraged not to use `pred' any longer,
  5902     because it will disappear altogether at some point.
  5903   - Users are strongly encouraged to write "0 < n" rather than
  5904     "n ~= 0". Theorems and proof tools have been modified towards this
  5905     `standard'.
  5906 
  5907 * HOL/Lists:
  5908   the function "set_of_list" has been renamed "set" (and its theorems too);
  5909   the function "nth" now takes its arguments in the reverse order and
  5910   has acquired the infix notation "!" as in "xs!n".
  5911 
  5912 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5913 
  5914 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5915   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5916 
  5917 * HOL/record: extensible records with schematic structural subtyping
  5918 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5919 still lacks various theorems and concrete record syntax;
  5920 
  5921 
  5922 *** HOLCF ***
  5923 
  5924 * removed "axioms" and "generated by" sections;
  5925 
  5926 * replaced "ops" section by extended "consts" section, which is capable of
  5927   handling the continuous function space "->" directly;
  5928 
  5929 * domain package:
  5930   . proves theorems immediately and stores them in the theory,
  5931   . creates hierachical name space,
  5932   . now uses normal mixfix annotations (instead of cinfix...),
  5933   . minor changes to some names and values (for consistency),
  5934   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5935   . separator between mutual domain defs: changed "," to "and",
  5936   . improved handling of sort constraints;  now they have to
  5937     appear on the left-hand side of the equations only;
  5938 
  5939 * fixed LAM <x,y,zs>.b syntax;
  5940 
  5941 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5942 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5943 
  5944 
  5945 *** FOL and ZF ***
  5946 
  5947 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5948   with `addloop' of the simplifier to faciliate case splitting in premises.
  5949 
  5950 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5951 in HOL, they strip ALL and --> from proved theorems;
  5952 
  5953 
  5954 
  5955 New in Isabelle94-8 (May 1997)
  5956 ------------------------------
  5957 
  5958 *** General Changes ***
  5959 
  5960 * new utilities to build / run / maintain Isabelle etc. (in parts
  5961 still somewhat experimental); old Makefiles etc. still functional;
  5962 
  5963 * new 'Isabelle System Manual';
  5964 
  5965 * INSTALL text, together with ./configure and ./build scripts;
  5966 
  5967 * reimplemented type inference for greater efficiency, better error
  5968 messages and clean internal interface;
  5969 
  5970 * prlim command for dealing with lots of subgoals (an easier way of
  5971 setting goals_limit);
  5972 
  5973 
  5974 *** Syntax ***
  5975 
  5976 * supports alternative (named) syntax tables (parser and pretty
  5977 printer); internal interface is provided by add_modesyntax(_i);
  5978 
  5979 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5980 be used in conjunction with the Isabelle symbol font; uses the
  5981 "symbols" syntax table;
  5982 
  5983 * added token_translation interface (may translate name tokens in
  5984 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5985 the current print_mode); IMPORTANT: user print translation functions
  5986 are responsible for marking newly introduced bounds
  5987 (Syntax.mark_boundT);
  5988 
  5989 * token translations for modes "xterm" and "xterm_color" that display
  5990 names in bold, underline etc. or colors (which requires a color
  5991 version of xterm);
  5992 
  5993 * infixes may now be declared with names independent of their syntax;
  5994 
  5995 * added typed_print_translation (like print_translation, but may
  5996 access type of constant);
  5997 
  5998 
  5999 *** Classical Reasoner ***
  6000 
  6001 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6002 some limitations.  Blast_tac...
  6003   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6004   + ignores elimination rules that don't have the correct format
  6005         (the conclusion MUST be a formula variable)
  6006   + ignores types, which can make HOL proofs fail
  6007   + rules must not require higher-order unification, e.g. apply_type in ZF
  6008     [message "Function Var's argument not a bound variable" relates to this]
  6009   + its proof strategy is more general but can actually be slower
  6010 
  6011 * substitution with equality assumptions no longer permutes other
  6012 assumptions;
  6013 
  6014 * minor changes in semantics of addafter (now called addaltern); renamed
  6015 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6016 (and access functions for it);
  6017 
  6018 * improved combination of classical reasoner and simplifier:
  6019   + functions for handling clasimpsets
  6020   + improvement of addss: now the simplifier is called _after_ the
  6021     safe steps.
  6022   + safe variant of addss called addSss: uses safe simplifications
  6023     _during_ the safe steps. It is more complete as it allows multiple
  6024     instantiations of unknowns (e.g. with slow_tac).
  6025 
  6026 *** Simplifier ***
  6027 
  6028 * added interface for simplification procedures (functions that
  6029 produce *proven* rewrite rules on the fly, depending on current
  6030 redex);
  6031 
  6032 * ordering on terms as parameter (used for ordered rewriting);
  6033 
  6034 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6035 
  6036 * the solver is now split into a safe and an unsafe part.
  6037 This should be invisible for the normal user, except that the
  6038 functions setsolver and addsolver have been renamed to setSolver and
  6039 addSolver; added safe_asm_full_simp_tac;
  6040 
  6041 
  6042 *** HOL ***
  6043 
  6044 * a generic induction tactic `induct_tac' which works for all datatypes and
  6045 also for type `nat';
  6046 
  6047 * a generic case distinction tactic `exhaust_tac' which works for all
  6048 datatypes and also for type `nat';
  6049 
  6050 * each datatype comes with a function `size';
  6051 
  6052 * patterns in case expressions allow tuple patterns as arguments to
  6053 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6054 
  6055 * primrec now also works with type nat;
  6056 
  6057 * recdef: a new declaration form, allows general recursive functions to be
  6058 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6059 
  6060 * the constant for negation has been renamed from "not" to "Not" to
  6061 harmonize with FOL, ZF, LK, etc.;
  6062 
  6063 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6064 infinite lists;
  6065 
  6066 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6067 
  6068 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6069 problems in commutative rings, using axiomatic type classes for + and *;
  6070 
  6071 * more examples in HOL/MiniML and HOL/Auth;
  6072 
  6073 * more default rewrite rules for quantifiers, union/intersection;
  6074 
  6075 * a new constant `arbitrary == @x.False';
  6076 
  6077 * HOLCF/IOA replaces old HOL/IOA;
  6078 
  6079 * HOLCF changes: derived all rules and arities
  6080   + axiomatic type classes instead of classes
  6081   + typedef instead of faking type definitions
  6082   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6083   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6084   + eliminated the types void, one, tr
  6085   + use unit lift and bool lift (with translations) instead of one and tr
  6086   + eliminated blift from Lift3.thy (use Def instead of blift)
  6087   all eliminated rules are derived as theorems --> no visible changes ;
  6088 
  6089 
  6090 *** ZF ***
  6091 
  6092 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6093 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6094 as ZF_cs addSIs [equalityI];
  6095 
  6096 
  6097 
  6098 New in Isabelle94-7 (November 96)
  6099 ---------------------------------
  6100 
  6101 * allowing negative levels (as offsets) in prlev and choplev;
  6102 
  6103 * super-linear speedup for large simplifications;
  6104 
  6105 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6106 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6107 FAIL); can suppress it using the command Delsimps (ex_simps @
  6108 all_simps); De Morgan laws are also now included, by default;
  6109 
  6110 * improved printing of ==>  :  ~:
  6111 
  6112 * new object-logic "Sequents" adds linear logic, while replacing LK
  6113 and Modal (thanks to Sara Kalvala);
  6114 
  6115 * HOL/Auth: correctness proofs for authentication protocols;
  6116 
  6117 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6118 examples on HOL/Auth);
  6119 
  6120 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6121 the rewriter and classical reasoner simultaneously;
  6122 
  6123 * function uresult no longer returns theorems in "standard" format;
  6124 regain previous version by: val uresult = standard o uresult;
  6125 
  6126 
  6127 
  6128 New in Isabelle94-6
  6129 -------------------
  6130 
  6131 * oracles -- these establish an interface between Isabelle and trusted
  6132 external reasoners, which may deliver results as theorems;
  6133 
  6134 * proof objects (in particular record all uses of oracles);
  6135 
  6136 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6137 
  6138 * "constdefs" section in theory files;
  6139 
  6140 * "primrec" section (HOL) no longer requires names;
  6141 
  6142 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6143 
  6144 
  6145 
  6146 New in Isabelle94-5
  6147 -------------------
  6148 
  6149 * reduced space requirements;
  6150 
  6151 * automatic HTML generation from theories;
  6152 
  6153 * theory files no longer require "..." (quotes) around most types;
  6154 
  6155 * new examples, including two proofs of the Church-Rosser theorem;
  6156 
  6157 * non-curried (1994) version of HOL is no longer distributed;
  6158 
  6159 
  6160 
  6161 New in Isabelle94-4
  6162 -------------------
  6163 
  6164 * greatly reduced space requirements;
  6165 
  6166 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6167 
  6168 * searchable theorem database (see the section "Retrieving theorems" on
  6169 page 8 of the Reference Manual);
  6170 
  6171 * new examples, including Grabczewski's monumental case study of the
  6172 Axiom of Choice;
  6173 
  6174 * The previous version of HOL renamed to Old_HOL;
  6175 
  6176 * The new version of HOL (previously called CHOL) uses a curried syntax
  6177 for functions.  Application looks like f a b instead of f(a,b);
  6178 
  6179 * Mutually recursive inductive definitions finally work in HOL;
  6180 
  6181 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6182 translates to the operator "split";
  6183 
  6184 
  6185 
  6186 New in Isabelle94-3
  6187 -------------------
  6188 
  6189 * new infix operator, addss, allowing the classical reasoner to
  6190 perform simplification at each step of its search.  Example:
  6191         fast_tac (cs addss ss)
  6192 
  6193 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6194 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6195 look like (a,b) instead of <a,b>;
  6196 
  6197 * PLEASE NOTE: CHOL will eventually replace HOL!
  6198 
  6199 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6200 It translates to the operator "split".  A new theory of integers is available;
  6201 
  6202 * In ZF, integer numerals now denote two's-complement binary integers.
  6203 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6204 
  6205 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6206 of the Axiom of Choice;
  6207 
  6208 
  6209 
  6210 New in Isabelle94-2
  6211 -------------------
  6212 
  6213 * Significantly faster resolution;
  6214 
  6215 * the different sections in a .thy file can now be mixed and repeated
  6216 freely;
  6217 
  6218 * Database of theorems for FOL, HOL and ZF.  New
  6219 commands including qed, qed_goal and bind_thm store theorems in the database.
  6220 
  6221 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6222 a given theory (thms_of), or find out what theory a theorem was proved in
  6223 (theory_of_thm);
  6224 
  6225 * Bugs fixed in the inductive definition and datatype packages;
  6226 
  6227 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6228 and HOL_dup_cs obsolete;
  6229 
  6230 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6231 have been removed;
  6232 
  6233 * Simpler definition of function space in ZF;
  6234 
  6235 * new results about cardinal and ordinal arithmetic in ZF;
  6236 
  6237 * 'subtype' facility in HOL for introducing new types as subsets of existing
  6238 types;
  6239 
  6240 :mode=text:wrap=hard:maxLineLen=72: