NEWS
author wenzelm
Mon Apr 20 12:26:31 2009 +0200 (2009-04-20)
changeset 30904 cc6a6047a10f
parent 30855 c22436e6d350
child 30957 20d01210b9b1
permissions -rw-r--r--
back to non-release mode;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 
     8 
     9 New in Isabelle2009 (April 2009)
    10 --------------------------------
    11 
    12 *** General ***
    13 
    14 * Simplified main Isabelle executables, with less surprises on
    15 case-insensitive file-systems (such as Mac OS).
    16 
    17   - The main Isabelle tool wrapper is now called "isabelle" instead of
    18     "isatool."
    19 
    20   - The former "isabelle" alias for "isabelle-process" has been
    21     removed (should rarely occur to regular users).
    22 
    23   - The former "isabelle-interface" and its alias "Isabelle" have been
    24     removed (interfaces are now regular Isabelle tools).
    25 
    26 Within scripts and make files, the Isabelle environment variables
    27 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    28 respectively.  (The latter are still available as legacy feature.)
    29 
    30 The old isabelle-interface wrapper could react in confusing ways if
    31 the interface was uninstalled or changed otherwise.  Individual
    32 interface tool configuration is now more explicit, see also the
    33 Isabelle system manual.  In particular, Proof General is now available
    34 via "isabelle emacs".
    35 
    36 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    37 purge installed copies of Isabelle executables and re-run "isabelle
    38 install -p ...", or use symlinks.
    39 
    40 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    41 old ~/isabelle, which was slightly non-standard and apt to cause
    42 surprises on case-insensitive file-systems (such as Mac OS).
    43 
    44 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    45 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    46 care is required when using older releases of Isabelle.  Note that
    47 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    48 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
    49 
    50 * Proofs of fully specified statements are run in parallel on
    51 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
    52 a regular 4-core machine, if the initial heap space is made reasonably
    53 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
    54 
    55 * The main reference manuals ("isar-ref", "implementation", and
    56 "system") have been updated and extended.  Formally checked references
    57 as hyperlinks are now available uniformly.
    58 
    59 
    60 *** Pure ***
    61 
    62 * Complete re-implementation of locales.  INCOMPATIBILITY in several
    63 respects.  The most important changes are listed below.  See the
    64 Tutorial on Locales ("locales" manual) for details.
    65 
    66 - In locale expressions, instantiation replaces renaming.  Parameters
    67 must be declared in a for clause.  To aid compatibility with previous
    68 parameter inheritance, in locale declarations, parameters that are not
    69 'touched' (instantiation position "_" or omitted) are implicitly added
    70 with their syntax at the beginning of the for clause.
    71 
    72 - Syntax from abbreviations and definitions in locales is available in
    73 locale expressions and context elements.  The latter is particularly
    74 useful in locale declarations.
    75 
    76 - More flexible mechanisms to qualify names generated by locale
    77 expressions.  Qualifiers (prefixes) may be specified in locale
    78 expressions, and can be marked as mandatory (syntax: "name!:") or
    79 optional (syntax "name?:").  The default depends for plain "name:"
    80 depends on the situation where a locale expression is used: in
    81 commands 'locale' and 'sublocale' prefixes are optional, in
    82 'interpretation' and 'interpret' prefixes are mandatory.  The old
    83 implicit qualifiers derived from the parameter names of a locale are
    84 no longer generated.
    85 
    86 - Command "sublocale l < e" replaces "interpretation l < e".  The
    87 instantiation clause in "interpretation" and "interpret" (square
    88 brackets) is no longer available.  Use locale expressions.
    89 
    90 - When converting proof scripts, mandatory qualifiers in
    91 'interpretation' and 'interpret' should be retained by default, even
    92 if this is an INCOMPATIBILITY compared to former behavior.  In the
    93 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
    94 in locale expressions range over a single locale instance only.
    95 
    96 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
    97 In existing theorem specifications replace the includes element by the
    98 respective context elements of the included locale, omitting those
    99 that are already present in the theorem specification.  Multiple
   100 assume elements of a locale should be replaced by a single one
   101 involving the locale predicate.  In the proof body, declarations (most
   102 notably theorems) may be regained by interpreting the respective
   103 locales in the proof context as required (command "interpret").
   104 
   105 If using "includes" in replacement of a target solely because the
   106 parameter types in the theorem are not as general as in the target,
   107 consider declaring a new locale with additional type constraints on
   108 the parameters (context element "constrains").
   109 
   110 - Discontinued "locale (open)".  INCOMPATIBILITY.
   111 
   112 - Locale interpretation commands no longer attempt to simplify goal.
   113 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   114 methods intro_locales and unfold_locales to clarify.
   115 
   116 - Locale interpretation commands no longer accept interpretation
   117 attributes.  INCOMPATIBILITY.
   118 
   119 * Class declaration: so-called "base sort" must not be given in import
   120 list any longer, but is inferred from the specification.  Particularly
   121 in HOL, write
   122 
   123     class foo = ...
   124 
   125 instead of
   126 
   127     class foo = type + ...
   128 
   129 * Class target: global versions of theorems stemming do not carry a
   130 parameter prefix any longer.  INCOMPATIBILITY.
   131 
   132 * Class 'instance' command no longer accepts attached definitions.
   133 INCOMPATIBILITY, use proper 'instantiation' target instead.
   134 
   135 * Recovered hiding of consts, which was accidentally broken in
   136 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   137 makes c inaccessible; consider using ``hide (open) const c'' instead.
   138 
   139 * Slightly more coherent Pure syntax, with updated documentation in
   140 isar-ref manual.  Removed locales meta_term_syntax and
   141 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   142 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   143 directly in regular applications.
   144 
   145 * There is a new syntactic category "float_const" for signed decimal
   146 fractions (e.g. 123.45 or -123.45).
   147 
   148 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   149 interface with 'setup' command instead.
   150 
   151 * Command 'local_setup' is similar to 'setup', but operates on a local
   152 theory context.
   153 
   154 * The 'axiomatization' command now only works within a global theory
   155 context.  INCOMPATIBILITY.
   156 
   157 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   158 hypotheses.  Sorts required in the course of reasoning need to be
   159 covered by the constraints in the initial statement, completed by the
   160 type instance information of the background theory.  Non-trivial sort
   161 hypotheses, which rarely occur in practice, may be specified via
   162 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   163 
   164   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   165 
   166 The result contains an implicit sort hypotheses as before --
   167 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   168 normalization.
   169 
   170 * Generalized Isar history, with support for linear undo, direct state
   171 addressing etc.
   172 
   173 * Changed defaults for unify configuration options:
   174 
   175   unify_trace_bound = 50 (formerly 25)
   176   unify_search_bound = 60 (formerly 30)
   177 
   178 * Different bookkeeping for code equations (INCOMPATIBILITY):
   179 
   180   a) On theory merge, the last set of code equations for a particular
   181      constant is taken (in accordance with the policy applied by other
   182      parts of the code generator framework).
   183 
   184   b) Code equations stemming from explicit declarations (e.g. code
   185      attribute) gain priority over default code equations stemming
   186      from definition, primrec, fun etc.
   187 
   188 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   189 
   190 * Unified theorem tables for both code code generators.  Thus [code
   191 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   192 
   193 * Command 'find_consts' searches for constants based on type and name
   194 patterns, e.g.
   195 
   196     find_consts "_ => bool"
   197 
   198 By default, matching is against subtypes, but it may be restricted to
   199 the whole type.  Searching by name is possible.  Multiple queries are
   200 conjunctive and queries may be negated by prefixing them with a
   201 hyphen:
   202 
   203     find_consts strict: "_ => bool" name: "Int" -"int => int"
   204 
   205 * New 'find_theorems' criterion "solves" matches theorems that
   206 directly solve the current goal (modulo higher-order unification).
   207 
   208 * Auto solve feature for main theorem statements: whenever a new goal
   209 is stated, "find_theorems solves" is called; any theorems that could
   210 solve the lemma directly are listed as part of the goal state.
   211 Cf. associated options in Proof General Isabelle settings menu,
   212 enabled by default, with reasonable timeout for pathological cases of
   213 higher-order unification.
   214 
   215 
   216 *** Document preparation ***
   217 
   218 * Antiquotation @{lemma} now imitates a regular terminal proof,
   219 demanding keyword 'by' and supporting the full method expression
   220 syntax just like the Isar command 'by'.
   221 
   222 
   223 *** HOL ***
   224 
   225 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   226 points Main and Complex_Main remain as before.
   227 
   228 * Logic image HOL-Plain provides a minimal HOL with the most important
   229 tools available (inductive, datatype, primrec, ...).  This facilitates
   230 experimentation and tool development.  Note that user applications
   231 (and library theories) should never refer to anything below theory
   232 Main, as before.
   233 
   234 * Logic image HOL-Main stops at theory Main, and thus facilitates
   235 experimentation due to shorter build times.
   236 
   237 * Logic image HOL-NSA contains theories of nonstandard analysis which
   238 were previously part of former HOL-Complex.  Entry point Hyperreal
   239 remains valid, but theories formerly using Complex_Main should now use
   240 new entry point Hypercomplex.
   241 
   242 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   243 Posix processes.  Avoids potentially expensive forking of the ML
   244 process.  New thread-based implementation also works on non-Unix
   245 platforms (Cygwin).  Provers are no longer hardwired, but defined
   246 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   247 commands are covered in the isar-ref manual.
   248 
   249 * Wrapper scripts for remote SystemOnTPTP service allows to use
   250 sledgehammer without local ATP installation (Vampire etc.). Other
   251 provers may be included via suitable ML wrappers, see also
   252 src/HOL/ATP_Linkup.thy.
   253 
   254 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   255 menu.
   256 
   257 * The metis method no longer fails because the theorem is too trivial
   258 (contains the empty clause).
   259 
   260 * The metis method now fails in the usual manner, rather than raising
   261 an exception, if it determines that it cannot prove the theorem.
   262 
   263 * Method "coherent" implements a prover for coherent logic (see also
   264 src/Tools/coherent.ML).
   265 
   266 * Constants "undefined" and "default" replace "arbitrary".  Usually
   267 "undefined" is the right choice to replace "arbitrary", though
   268 logically there is no difference.  INCOMPATIBILITY.
   269 
   270 * Command "value" now integrates different evaluation mechanisms.  The
   271 result of the first successful evaluation mechanism is printed.  In
   272 square brackets a particular named evaluation mechanisms may be
   273 specified (currently, [SML], [code] or [nbe]).  See further
   274 src/HOL/ex/Eval_Examples.thy.
   275 
   276 * Normalization by evaluation now allows non-leftlinear equations.
   277 Declare with attribute [code nbe].
   278 
   279 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   280 as the structured Isar versions "cases" and "induct", cf. the
   281 corresponding "cases" and "induct" attributes.  Mutual induction rules
   282 are now presented as a list of individual projections
   283 (e.g. foo_bar.inducts for types foo and bar); the old format with
   284 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   285 rare situations a different rule is selected --- notably nested tuple
   286 elimination instead of former prod.exhaust: use explicit (case_tac t
   287 rule: prod.exhaust) here.
   288 
   289 * Attributes "cases", "induct", "coinduct" support "del" option.
   290 
   291 * Removed fact "case_split_thm", which duplicates "case_split".
   292 
   293 * The option datatype has been moved to a new theory Option.  Renamed
   294 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   295 
   296 * New predicate "strict_mono" classifies strict functions on partial
   297 orders.  With strict functions on linear orders, reasoning about
   298 (in)equalities is facilitated by theorems "strict_mono_eq",
   299 "strict_mono_less_eq" and "strict_mono_less".
   300 
   301 * Some set operations are now proper qualified constants with
   302 authentic syntax.  INCOMPATIBILITY:
   303 
   304     op Int ~>   Set.Int
   305     op Un ~>    Set.Un
   306     INTER ~>    Set.INTER
   307     UNION ~>    Set.UNION
   308     Inter ~>    Set.Inter
   309     Union ~>    Set.Union
   310     {} ~>       Set.empty
   311     UNIV ~>     Set.UNIV
   312 
   313 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   314 theory Set.
   315 
   316 * Auxiliary class "itself" has disappeared -- classes without any
   317 parameter are treated as expected by the 'class' command.
   318 
   319 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   320 
   321 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   322 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   323 
   324 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   325 method "approximation".  It proves formulas on real values by using
   326 interval arithmetic.  In the formulas are also the transcendental
   327 functions sin, cos, tan, atan, ln, exp and the constant pi are
   328 allowed. For examples see
   329 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   330 
   331 * Theory "Reflection" now resides in HOL/Library.
   332 
   333 * Entry point to Word library now simply named "Word".
   334 INCOMPATIBILITY.
   335 
   336 * Made source layout more coherent with logical distribution
   337 structure:
   338 
   339     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   340     src/HOL/Library/Code_Message.thy ~> src/HOL/
   341     src/HOL/Library/GCD.thy ~> src/HOL/
   342     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   343     src/HOL/Library/Parity.thy ~> src/HOL/
   344     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   345     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   346     src/HOL/Real/Lubs.thy ~> src/HOL/
   347     src/HOL/Real/PReal.thy ~> src/HOL/
   348     src/HOL/Real/Rational.thy ~> src/HOL/
   349     src/HOL/Real/RComplete.thy ~> src/HOL/
   350     src/HOL/Real/RealDef.thy ~> src/HOL/
   351     src/HOL/Real/RealPow.thy ~> src/HOL/
   352     src/HOL/Real/Real.thy ~> src/HOL/
   353     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   354     src/HOL/Complex/Complex.thy ~> src/HOL/
   355     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   356     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   357     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   358     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   359     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   360     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   361     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   362     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   363     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   364     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   365     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   366     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   367     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   368     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   369     src/HOL/Real/Float ~> src/HOL/Library/
   370     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   371     src/HOL/Real/RealVector.thy ~> src/HOL/
   372 
   373     src/HOL/arith_data.ML ~> src/HOL/Tools
   374     src/HOL/hologic.ML ~> src/HOL/Tools
   375     src/HOL/simpdata.ML ~> src/HOL/Tools
   376     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   377     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   378     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   379     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   380     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   381     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   382     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   383 
   384     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   385     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   386     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   387     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   388     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   389     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   390 
   391 * If methods "eval" and "evaluation" encounter a structured proof
   392 state with !!/==>, only the conclusion is evaluated to True (if
   393 possible), avoiding strange error messages.
   394 
   395 * Method "sizechange" automates termination proofs using (a
   396 modification of) the size-change principle.  Requires SAT solver.  See
   397 src/HOL/ex/Termination.thy for examples.
   398 
   399 * Simplifier: simproc for let expressions now unfolds if bound
   400 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   401 
   402 * Method "arith": Linear arithmetic now ignores all inequalities when
   403 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   404 
   405 * New attribute "arith" for facts that should always be used
   406 automatically by arithmetic. It is intended to be used locally in
   407 proofs, e.g.
   408 
   409   assumes [arith]: "x > 0"
   410 
   411 Global usage is discouraged because of possible performance impact.
   412 
   413 * New classes "top" and "bot" with corresponding operations "top" and
   414 "bot" in theory Orderings; instantiation of class "complete_lattice"
   415 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   416 
   417 * Changed definition lemma "less_fun_def" in order to provide an
   418 instance for preorders on functions; use lemma "less_le" instead.
   419 INCOMPATIBILITY.
   420 
   421 * Theory Orderings: class "wellorder" moved here, with explicit
   422 induction rule "less_induct" as assumption.  For instantiation of
   423 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   424 INCOMPATIBILITY.
   425 
   426 * Theory Orderings: added class "preorder" as superclass of "order".
   427 INCOMPATIBILITY: Instantiation proofs for order, linorder
   428 etc. slightly changed.  Some theorems named order_class.* now named
   429 preorder_class.*.
   430 
   431 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   432 "diag" to "Id_on".
   433 
   434 * Theory Finite_Set: added a new fold combinator of type
   435 
   436   ('a => 'b => 'b) => 'b => 'a set => 'b
   437 
   438 Occasionally this is more convenient than the old fold combinator
   439 which is now defined in terms of the new one and renamed to
   440 fold_image.
   441 
   442 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   443 and "ring_simps" have been replaced by "algebra_simps" (which can be
   444 extended with further lemmas!).  At the moment both still exist but
   445 the former will disappear at some point.
   446 
   447 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   448 class recpower.  Type-specific simp rules for various recpower types
   449 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   450 
   451 rat_power_0    -> power_0
   452 rat_power_Suc  -> power_Suc
   453 realpow_0      -> power_0
   454 realpow_Suc    -> power_Suc
   455 complexpow_0   -> power_0
   456 complexpow_Suc -> power_Suc
   457 power_poly_0   -> power_0
   458 power_poly_Suc -> power_Suc
   459 
   460 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   461 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   462 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   463 of lemmas from Divides has been generalized from nat to class
   464 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   465 renames resulting from duplicate elimination:
   466 
   467     dvd_def_mod ~>          dvd_eq_mod_eq_0
   468     zero_dvd_iff ~>         dvd_0_left_iff
   469     dvd_0 ~>                dvd_0_right
   470     DIVISION_BY_ZERO_DIV ~> div_by_0
   471     DIVISION_BY_ZERO_MOD ~> mod_by_0
   472     mult_div ~>             div_mult_self2_is_id
   473     mult_mod ~>             mod_mult_self2_is_0
   474 
   475 * Theory IntDiv: removed many lemmas that are instances of class-based
   476 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   477 rename old lemmas as follows:
   478 
   479 dvd_diff               -> nat_dvd_diff
   480 dvd_zminus_iff         -> dvd_minus_iff
   481 mod_add1_eq            -> mod_add_eq
   482 mod_mult1_eq           -> mod_mult_right_eq
   483 mod_mult1_eq'          -> mod_mult_left_eq
   484 mod_mult_distrib_mod   -> mod_mult_eq
   485 nat_mod_add_left_eq    -> mod_add_left_eq
   486 nat_mod_add_right_eq   -> mod_add_right_eq
   487 nat_mod_div_trivial    -> mod_div_trivial
   488 nat_mod_mod_trivial    -> mod_mod_trivial
   489 zdiv_zadd_self1        -> div_add_self1
   490 zdiv_zadd_self2        -> div_add_self2
   491 zdiv_zmult_self1       -> div_mult_self2_is_id
   492 zdiv_zmult_self2       -> div_mult_self1_is_id
   493 zdvd_triv_left         -> dvd_triv_left
   494 zdvd_triv_right        -> dvd_triv_right
   495 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   496 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   497 zmod_zadd_left_eq      -> mod_add_left_eq
   498 zmod_zadd_right_eq     -> mod_add_right_eq
   499 zmod_zadd_self1        -> mod_add_self1
   500 zmod_zadd_self2        -> mod_add_self2
   501 zmod_zadd1_eq          -> mod_add_eq
   502 zmod_zdiff1_eq         -> mod_diff_eq
   503 zmod_zdvd_zmod         -> mod_mod_cancel
   504 zmod_zmod_cancel       -> mod_mod_cancel
   505 zmod_zmult_self1       -> mod_mult_self2_is_0
   506 zmod_zmult_self2       -> mod_mult_self1_is_0
   507 zmod_1                 -> mod_by_1
   508 zdiv_1                 -> div_by_1
   509 zdvd_abs1              -> abs_dvd_iff
   510 zdvd_abs2              -> dvd_abs_iff
   511 zdvd_refl              -> dvd_refl
   512 zdvd_trans             -> dvd_trans
   513 zdvd_zadd              -> dvd_add
   514 zdvd_zdiff             -> dvd_diff
   515 zdvd_zminus_iff        -> dvd_minus_iff
   516 zdvd_zminus2_iff       -> minus_dvd_iff
   517 zdvd_zmultD            -> dvd_mult_right
   518 zdvd_zmultD2           -> dvd_mult_left
   519 zdvd_zmult_mono        -> mult_dvd_mono
   520 zdvd_0_right           -> dvd_0_right
   521 zdvd_0_left            -> dvd_0_left_iff
   522 zdvd_1_left            -> one_dvd
   523 zminus_dvd_iff         -> minus_dvd_iff
   524 
   525 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   526 
   527 * The real numbers offer decimal input syntax: 12.34 is translated
   528 into 1234/10^2. This translation is not reversed upon output.
   529 
   530 * Theory Library/Polynomial defines an abstract type 'a poly of
   531 univariate polynomials with coefficients of type 'a.  In addition to
   532 the standard ring operations, it also supports div and mod.  Code
   533 generation is also supported, using list-style constructors.
   534 
   535 * Theory Library/Inner_Product defines a class of real_inner for real
   536 inner product spaces, with an overloaded operation inner :: 'a => 'a
   537 => real.  Class real_inner is a subclass of real_normed_vector from
   538 theory RealVector.
   539 
   540 * Theory Library/Product_Vector provides instances for the product
   541 type 'a * 'b of several classes from RealVector and Inner_Product.
   542 Definitions of addition, subtraction, scalar multiplication, norms,
   543 and inner products are included.
   544 
   545 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   546 addition to the field operations, numerals and case syntax are also
   547 supported.
   548 
   549 * Theory Library/Diagonalize provides constructive version of Cantor's
   550 first diagonalization argument.
   551 
   552 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   553 zlcm (for int); carried together from various gcd/lcm developements in
   554 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   555 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   556 may recover tupled syntax as follows:
   557 
   558     hide (open) const gcd
   559     abbreviation gcd where
   560       "gcd == (%(a, b). GCD.gcd a b)"
   561     notation (output)
   562       GCD.gcd ("gcd '(_, _')")
   563 
   564 The same works for lcm, zgcd, zlcm.
   565 
   566 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   567 instantiations for algebraic structures.  Removed some duplicate
   568 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   569 
   570 * ML antiquotation @{code} takes a constant as argument and generates
   571 corresponding code in background and inserts name of the corresponding
   572 resulting ML value/function/datatype constructor binding in place.
   573 All occurrences of @{code} with a single ML block are generated
   574 simultaneously.  Provides a generic and safe interface for
   575 instrumentalizing code generation.  See
   576 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   577 In future you ought to refrain from ad-hoc compiling generated SML
   578 code on the ML toplevel.  Note that (for technical reasons) @{code}
   579 cannot refer to constants for which user-defined serializations are
   580 set.  Refer to the corresponding ML counterpart directly in that
   581 cases.
   582 
   583 * Command 'rep_datatype': instead of theorem names the command now
   584 takes a list of terms denoting the constructors of the type to be
   585 represented as datatype.  The characteristic theorems have to be
   586 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   587 have disappeared in favour of existing ones:
   588 
   589     unit_induct                 ~> unit.induct
   590     prod_induct                 ~> prod.induct
   591     sum_induct                  ~> sum.induct
   592     Suc_Suc_eq                  ~> nat.inject
   593     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   594 
   595 
   596 *** HOL-Algebra ***
   597 
   598 * New locales for orders and lattices where the equivalence relation
   599 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   600 locales use a record structure with field eq for the equivalence.
   601 
   602 * New theory of factorial domains.
   603 
   604 * Units_l_inv and Units_r_inv are now simp rules by default.
   605 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   606 and/or r_inv will now also require deletion of these lemmas.
   607 
   608 * Renamed the following theorems, INCOMPATIBILITY:
   609 
   610 UpperD ~> Upper_memD
   611 LowerD ~> Lower_memD
   612 least_carrier ~> least_closed
   613 greatest_carrier ~> greatest_closed
   614 greatest_Lower_above ~> greatest_Lower_below
   615 one_zero ~> carrier_one_zero
   616 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   617 
   618 
   619 *** HOL-Nominal ***
   620 
   621 * Nominal datatypes can now contain type-variables.
   622 
   623 * Commands 'nominal_inductive' and 'equivariance' work with local
   624 theory targets.
   625 
   626 * Nominal primrec can now works with local theory targets and its
   627 specification syntax now conforms to the general format as seen in
   628 'inductive' etc.
   629 
   630 * Method "perm_simp" honours the standard simplifier attributes
   631 (no_asm), (no_asm_use) etc.
   632 
   633 * The new predicate #* is defined like freshness, except that on the
   634 left hand side can be a set or list of atoms.
   635 
   636 * Experimental command 'nominal_inductive2' derives strong induction
   637 principles for inductive definitions.  In contrast to
   638 'nominal_inductive', which can only deal with a fixed number of
   639 binders, it can deal with arbitrary expressions standing for sets of
   640 atoms to be avoided.  The only inductive definition we have at the
   641 moment that needs this generalisation is the typing rule for Lets in
   642 the algorithm W:
   643 
   644  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   645  -----------------------------------------------------------------
   646          Gamma |- Let x be t1 in t2 : T2
   647 
   648 In this rule one wants to avoid all the binders that are introduced by
   649 "close Gamma T1".  We are looking for other examples where this
   650 feature might be useful.  Please let us know.
   651 
   652 
   653 *** HOLCF ***
   654 
   655 * Reimplemented the simplification procedure for proving continuity
   656 subgoals.  The new simproc is extensible; users can declare additional
   657 continuity introduction rules with the attribute [cont2cont].
   658 
   659 * The continuity simproc now uses a different introduction rule for
   660 solving continuity subgoals on terms with lambda abstractions.  In
   661 some rare cases the new simproc may fail to solve subgoals that the
   662 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   663 Potential INCOMPATIBILITY.
   664 
   665 * Command 'fixrec': specification syntax now conforms to the general
   666 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   667 examples.  INCOMPATIBILITY.
   668 
   669 
   670 *** ZF ***
   671 
   672 * Proof of Zorn's Lemma for partial orders.
   673 
   674 
   675 *** ML ***
   676 
   677 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   678 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   679 depends on multithreading, so timouts will not work before Poly/ML
   680 5.2.1!
   681 
   682 * High-level support for concurrent ML programming, see
   683 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   684 particularly convenient to organize independent functional
   685 computations.  The concept of "synchronized variables" provides a
   686 higher-order interface for components with shared state, avoiding the
   687 delicate details of mutexes and condition variables.  (Requires
   688 Poly/ML 5.2.1 or later.)
   689 
   690 * ML bindings produced via Isar commands are stored within the Isar
   691 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   692 become thread-safe and work with undo as expected (concerning
   693 top-level bindings, not side-effects on global references).
   694 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   695 compiler at runtime; really global bindings need to be given outside a
   696 theory.  (Requires Poly/ML 5.2 or later.)
   697 
   698 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   699 context.  Top-level ML bindings are stored within the proof context in
   700 a purely sequential fashion, disregarding the nested proof structure.
   701 ML bindings introduced by 'ML_prf' are discarded at the end of the
   702 proof.  (Requires Poly/ML 5.2 or later.)
   703 
   704 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   705 and Method.setup, as well as Isar commands 'attribute_setup' and
   706 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   707 existing code accordingly, or use plain 'setup' together with old
   708 Method.add_method.
   709 
   710 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   711 to 'a -> thm, while results are always tagged with an authentic oracle
   712 name.  The Isar command 'oracle' is now polymorphic, no argument type
   713 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   714 accordingly.  Note that extra performance may be gained by producing
   715 the cterm carefully, avoiding slow Thm.cterm_of.
   716 
   717 * Simplified interface for defining document antiquotations via
   718 ThyOutput.antiquotation, ThyOutput.output, and optionally
   719 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   720 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   721 examples.
   722 
   723 * More systematic treatment of long names, abstract name bindings, and
   724 name space operations.  Basic operations on qualified names have been
   725 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   726 Long_Name.append.  Old type bstring has been mostly replaced by
   727 abstract type binding (see structure Binding), which supports precise
   728 qualification by packages and local theory targets, as well as proper
   729 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   730 bstring values into Binding.name, or better pass through abstract
   731 bindings everywhere.  See further src/Pure/General/long_name.ML,
   732 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   733 
   734 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   735 LocalTheory.note etc.) now refer to the *full* internal name, not the
   736 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   737 
   738 * Disposed old type and term read functions (Sign.read_def_typ,
   739 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   740 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   741 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   742 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   743 resort for legacy applications.
   744 
   745 * Disposed old declarations, tactics, tactic combinators that refer to
   746 the simpset or claset of an implicit theory (such as Addsimps,
   747 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   748 embedded ML text, or local_simpset_of with a proper context passed as
   749 explicit runtime argument.
   750 
   751 * Rules and tactics that read instantiations (read_instantiate,
   752 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   753 context, which is required for parsing and type-checking.  Moreover,
   754 the variables are specified as plain indexnames, not string encodings
   755 thereof.  INCOMPATIBILITY.
   756 
   757 * Generic Toplevel.add_hook interface allows to analyze the result of
   758 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   759 for theorem dependency output of transactions resulting in a new
   760 theory state.
   761 
   762 * ML antiquotations: block-structured compilation context indicated by
   763 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   764 
   765   @{binding name}                         - basic name binding
   766   @{let ?pat = term}                      - term abbreviation (HO matching)
   767   @{note name = fact}                     - fact abbreviation
   768   @{thm fact}                             - singleton fact (with attributes)
   769   @{thms fact}                            - general fact (with attributes)
   770   @{lemma prop by method}                 - singleton goal
   771   @{lemma prop by meth1 meth2}            - singleton goal
   772   @{lemma prop1 ... propN by method}      - general goal
   773   @{lemma prop1 ... propN by meth1 meth2} - general goal
   774   @{lemma (open) ...}                     - open derivation
   775 
   776 
   777 *** System ***
   778 
   779 * The Isabelle "emacs" tool provides a specific interface to invoke
   780 Proof General / Emacs, with more explicit failure if that is not
   781 installed (the old isabelle-interface script silently falls back on
   782 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   783 installation location of the Proof General distribution.
   784 
   785 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   786 the Isabelle process into a JVM/Scala application.  See
   787 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   788 process wrapper has been discontinued.)
   789 
   790 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   791 
   792 * Various status messages (with exact source position information) are
   793 emitted, if proper markup print mode is enabled.  This allows
   794 user-interface components to provide detailed feedback on internal
   795 prover operations.
   796 
   797 
   798 
   799 New in Isabelle2008 (June 2008)
   800 -------------------------------
   801 
   802 *** General ***
   803 
   804 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   805 and updated, with formally checked references as hyperlinks.
   806 
   807 * Theory loader: use_thy (and similar operations) no longer set the
   808 implicit ML context, which was occasionally hard to predict and in
   809 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   810 provides a proper context already.
   811 
   812 * Theory loader: old-style ML proof scripts being *attached* to a thy
   813 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   814 'use' within a theory file will do the job.
   815 
   816 * Name space merge now observes canonical order, i.e. the second space
   817 is inserted into the first one, while existing entries in the first
   818 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   819 swap theory imports.
   820 
   821 * Syntax: symbol \<chi> is now considered a letter.  Potential
   822 INCOMPATIBILITY in identifier syntax etc.
   823 
   824 * Outer syntax: string tokens no longer admit escaped white space,
   825 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   826 white space without escapes.
   827 
   828 * Outer syntax: string tokens may contain arbitrary character codes
   829 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   830 "foo_bar".
   831 
   832 
   833 *** Pure ***
   834 
   835 * Context-dependent token translations.  Default setup reverts locally
   836 fixed variables, and adds hilite markup for undeclared frees.
   837 
   838 * Unused theorems can be found using the new command 'unused_thms'.
   839 There are three ways of invoking it:
   840 
   841 (1) unused_thms
   842      Only finds unused theorems in the current theory.
   843 
   844 (2) unused_thms thy_1 ... thy_n -
   845      Finds unused theorems in the current theory and all of its ancestors,
   846      excluding the theories thy_1 ... thy_n and all of their ancestors.
   847 
   848 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   849      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   850      their ancestors, excluding the theories thy_1 ... thy_n and all of
   851      their ancestors.
   852 
   853 In order to increase the readability of the list produced by
   854 unused_thms, theorems that have been created by a particular instance
   855 of a theory command such as 'inductive' or 'function' are considered
   856 to belong to the same "group", meaning that if at least one theorem in
   857 this group is used, the other theorems in the same group are no longer
   858 reported as unused.  Moreover, if all theorems in the group are
   859 unused, only one theorem in the group is displayed.
   860 
   861 Note that proof objects have to be switched on in order for
   862 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   863 usually the case when using Proof General with the default settings).
   864 
   865 * Authentic naming of facts disallows ad-hoc overwriting of previous
   866 theorems within the same name space.  INCOMPATIBILITY, need to remove
   867 duplicate fact bindings, or even accidental fact duplications.  Note
   868 that tools may maintain dynamically scoped facts systematically, using
   869 PureThy.add_thms_dynamic.
   870 
   871 * Command 'hide' now allows to hide from "fact" name space as well.
   872 
   873 * Eliminated destructive theorem database, simpset, claset, and
   874 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   875 update of theories within ML code.
   876 
   877 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   878 INCOMPATIBILITY, object-logics depending on former Pure require
   879 additional setup PureThy.old_appl_syntax_setup; object-logics
   880 depending on former CPure need to refer to Pure.
   881 
   882 * Commands 'use' and 'ML' are now purely functional, operating on
   883 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   884 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   885 INCOMPATIBILITY.
   886 
   887 * Command 'setup': discontinued implicit version with ML reference.
   888 
   889 * Instantiation target allows for simultaneous specification of class
   890 instance operations together with an instantiation proof.
   891 Type-checking phase allows to refer to class operations uniformly.
   892 See src/HOL/Complex/Complex.thy for an Isar example and
   893 src/HOL/Library/Eval.thy for an ML example.
   894 
   895 * Indexing of literal facts: be more serious about including only
   896 facts from the visible specification/proof context, but not the
   897 background context (locale etc.).  Affects `prop` notation and method
   898 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   899 situations.
   900 
   901 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   902 "(open)" option, which used to expose internal bound variables to the
   903 proof text.
   904 
   905 * Isar statements: removed obsolete case "rule_context".
   906 INCOMPATIBILITY, better use explicit fixes/assumes.
   907 
   908 * Locale proofs: default proof step now includes 'unfold_locales';
   909 hence 'proof' without argument may be used to unfold locale
   910 predicates.
   911 
   912 
   913 *** Document preparation ***
   914 
   915 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   916 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   917 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   918 spot); renamed link color from "darkblue" to "linkcolor" (default
   919 value unchanged, can be redefined via \definecolor); no longer sets
   920 "a4paper" option (unnecessary or even intrusive).
   921 
   922 * Antiquotation @{lemma A method} proves proposition A by the given
   923 method (either a method name or a method name plus (optional) method
   924 arguments in parentheses) and prints A just like @{prop A}.
   925 
   926 
   927 *** HOL ***
   928 
   929 * New primrec package.  Specification syntax conforms in style to
   930 definition/function/....  No separate induction rule is provided.  The
   931 "primrec" command distinguishes old-style and new-style specifications
   932 by syntax.  The former primrec package is now named OldPrimrecPackage.
   933 When adjusting theories, beware: constants stemming from new-style
   934 primrec specifications have authentic syntax.
   935 
   936 * Metis prover is now an order of magnitude faster, and also works
   937 with multithreading.
   938 
   939 * Metis: the maximum number of clauses that can be produced from a
   940 theorem is now given by the attribute max_clauses.  Theorems that
   941 exceed this number are ignored, with a warning printed.
   942 
   943 * Sledgehammer no longer produces structured proofs by default. To
   944 enable, declare [[sledgehammer_full = true]].  Attributes
   945 reconstruction_modulus, reconstruction_sorts renamed
   946 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   947 
   948 * Method "induct_scheme" derives user-specified induction rules
   949 from well-founded induction and completeness of patterns. This factors
   950 out some operations that are done internally by the function package
   951 and makes them available separately.  See
   952 src/HOL/ex/Induction_Scheme.thy for examples.
   953 
   954 * More flexible generation of measure functions for termination
   955 proofs: Measure functions can be declared by proving a rule of the
   956 form "is_measure f" and giving it the [measure_function] attribute.
   957 The "is_measure" predicate is logically meaningless (always true), and
   958 just guides the heuristic.  To find suitable measure functions, the
   959 termination prover sets up the goal "is_measure ?f" of the appropriate
   960 type and generates all solutions by prolog-style backwards proof using
   961 the declared rules.
   962 
   963 This setup also deals with rules like 
   964 
   965   "is_measure f ==> is_measure (list_size f)"
   966 
   967 which accommodates nested datatypes that recurse through lists.
   968 Similar rules are predeclared for products and option types.
   969 
   970 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   971 
   972   INCOMPATIBILITIES:
   973 
   974   - Definitions of overloaded constants on sets have to be replaced by
   975     definitions on => and bool.
   976 
   977   - Some definitions of overloaded operators on sets can now be proved
   978     using the definitions of the operators on => and bool.  Therefore,
   979     the following theorems have been renamed:
   980 
   981       subset_def   -> subset_eq
   982       psubset_def  -> psubset_eq
   983       set_diff_def -> set_diff_eq
   984       Compl_def    -> Compl_eq
   985       Sup_set_def  -> Sup_set_eq
   986       Inf_set_def  -> Inf_set_eq
   987       sup_set_def  -> sup_set_eq
   988       inf_set_def  -> inf_set_eq
   989 
   990   - Due to the incompleteness of the HO unification algorithm, some
   991     rules such as subst may require manual instantiation, if some of
   992     the unknowns in the rule is a set.
   993 
   994   - Higher order unification and forward proofs:
   995     The proof pattern
   996 
   997       have "P (S::'a set)" <...>
   998       then have "EX S. P S" ..
   999 
  1000     no longer works (due to the incompleteness of the HO unification
  1001     algorithm) and must be replaced by the pattern
  1002 
  1003       have "EX S. P S"
  1004       proof
  1005         show "P S" <...>
  1006       qed
  1007 
  1008   - Calculational reasoning with subst (or similar rules):
  1009     The proof pattern
  1010 
  1011       have "P (S::'a set)" <...>
  1012       also have "S = T" <...>
  1013       finally have "P T" .
  1014 
  1015     no longer works (for similar reasons as the previous example) and
  1016     must be replaced by something like
  1017 
  1018       have "P (S::'a set)" <...>
  1019       moreover have "S = T" <...>
  1020       ultimately have "P T" by simp
  1021 
  1022   - Tactics or packages written in ML code:
  1023     Code performing pattern matching on types via
  1024 
  1025       Type ("set", [T]) => ...
  1026 
  1027     must be rewritten. Moreover, functions like strip_type or
  1028     binder_types no longer return the right value when applied to a
  1029     type of the form
  1030 
  1031       T1 => ... => Tn => U => bool
  1032 
  1033     rather than
  1034 
  1035       T1 => ... => Tn => U set
  1036 
  1037 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1038 Wellfounded_Relations to theory Wellfounded.
  1039 
  1040 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1041 
  1042 * Class finite no longer treats UNIV as class parameter.  Use class
  1043 enum from theory Library/Enum instead to achieve a similar effect.
  1044 INCOMPATIBILITY.
  1045 
  1046 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1047 and "Cons".  INCOMPATIBILITY.
  1048 
  1049 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1050 Potential INCOMPATIBILITY.
  1051 
  1052 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1053 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1054 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1055 
  1056 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1057 the same name in theory Orderings:
  1058 
  1059   less_trans
  1060   less_linear
  1061   le_imp_less_or_eq
  1062   le_less_trans
  1063   less_le_trans
  1064   less_not_sym
  1065   less_asym
  1066 
  1067 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1068 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1069 and different variable names.
  1070 
  1071 * Library/Option_ord.thy: Canonical order on option type.
  1072 
  1073 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1074 finite maps.
  1075 
  1076 * Library/Countable.thy: Type class for countable types.
  1077 
  1078 * Theory Int: The representation of numerals has changed.  The infix
  1079 operator BIT and the bit datatype with constructors B0 and B1 have
  1080 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1081 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1082 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1083 accordingly.
  1084 
  1085 * Theory Nat: definition of <= and < on natural numbers no longer
  1086 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1087 le_def and less_def have disappeared.  Consider lemmas not_less
  1088 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1089 
  1090 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1091 (whose purpose mainly is for various fold_set functionals) have been
  1092 abandoned in favor of the existing algebraic classes
  1093 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1094 lower_semilattice (resp. upper_semilattice) and linorder.
  1095 INCOMPATIBILITY.
  1096 
  1097 * Theory Transitive_Closure: induct and cases rules now declare proper
  1098 case_names ("base" and "step").  INCOMPATIBILITY.
  1099 
  1100 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1101 lattices.  The form set-specific version is available as
  1102 Inductive.lfp_ordinal_induct_set.
  1103 
  1104 * Renamed theorems "power.simps" to "power_int.simps".
  1105 INCOMPATIBILITY.
  1106 
  1107 * Class semiring_div provides basic abstract properties of semirings
  1108 with division and modulo operations.  Subsumes former class dvd_mod.
  1109 
  1110 * Merged theories IntDef, Numeral and IntArith into unified theory
  1111 Int.  INCOMPATIBILITY.
  1112 
  1113 * Theory Library/Code_Index: type "index" now represents natural
  1114 numbers rather than integers.  INCOMPATIBILITY.
  1115 
  1116 * New class "uminus" with operation "uminus" (split of from class
  1117 "minus" which now only has operation "minus", binary).
  1118 INCOMPATIBILITY.
  1119 
  1120 * Constants "card", "internal_split", "option_map" now with authentic
  1121 syntax.  INCOMPATIBILITY.
  1122 
  1123 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1124 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1125 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1126 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1127 Sup_set_def, le_def, less_def, option_map_def now with object
  1128 equality.  INCOMPATIBILITY.
  1129 
  1130 * Records. Removed K_record, and replaced it by pure lambda term
  1131 %x. c. The simplifier setup is now more robust against eta expansion.
  1132 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1133 
  1134 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1135 
  1136 * Library/ListVector: new theory of arithmetic vector operations.
  1137 
  1138 * Library/Order_Relation: new theory of various orderings as sets of
  1139 pairs.  Defines preorders, partial orders, linear orders and
  1140 well-orders on sets and on types.
  1141 
  1142 
  1143 *** ZF ***
  1144 
  1145 * Renamed some theories to allow to loading both ZF and HOL in the
  1146 same session:
  1147 
  1148   Datatype  -> Datatype_ZF
  1149   Inductive -> Inductive_ZF
  1150   Int       -> Int_ZF
  1151   IntDiv    -> IntDiv_ZF
  1152   Nat       -> Nat_ZF
  1153   List      -> List_ZF
  1154   Main      -> Main_ZF
  1155 
  1156 INCOMPATIBILITY: ZF theories that import individual theories below
  1157 Main might need to be adapted.  Regular theory Main is still
  1158 available, as trivial extension of Main_ZF.
  1159 
  1160 
  1161 *** ML ***
  1162 
  1163 * ML within Isar: antiquotation @{const name} or @{const
  1164 name(typargs)} produces statically-checked Const term.
  1165 
  1166 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1167 (of the same name).  Removed obsolete print command.
  1168 
  1169 * Removed obsolete "use_legacy_bindings" function.
  1170 
  1171 * The ``print mode'' is now a thread-local value derived from a global
  1172 template (the former print_mode reference), thus access becomes
  1173 non-critical.  The global print_mode reference is for session
  1174 management only; user-code should use print_mode_value,
  1175 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1176 
  1177 * Functions system/system_out provide a robust way to invoke external
  1178 shell commands, with propagation of interrupts (requires Poly/ML
  1179 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1180 
  1181 
  1182 *** System ***
  1183 
  1184 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1185 in accordance with Proof General 3.7, which prefers GNU emacs.
  1186 
  1187 * isatool tty runs Isabelle process with plain tty interaction;
  1188 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1189 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1190 
  1191 * isatool browser now works with Cygwin as well, using general
  1192 "javapath" function defined in Isabelle process environment.
  1193 
  1194 * YXML notation provides a simple and efficient alternative to
  1195 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1196 isatool yxml as described in the Isabelle system manual.
  1197 
  1198 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1199 provides general wrapper for managing an Isabelle process in a robust
  1200 fashion, with ``cooked'' output from stdin/stderr.
  1201 
  1202 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1203 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1204 
  1205 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1206 way of changing the user's settings is via
  1207 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1208 script.
  1209 
  1210 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1211 cores of the underlying machine, which is a good starting point for
  1212 optimal performance tuning.  The corresponding usedir option -M allows
  1213 "max" as an alias for "0".  WARNING: does not work on certain versions
  1214 of Mac OS (with Poly/ML 5.1).
  1215 
  1216 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1217 adverse effect of Isabelle flooding interactive front-ends (notably
  1218 ProofGeneral / XEmacs).
  1219 
  1220 
  1221 
  1222 New in Isabelle2007 (November 2007)
  1223 -----------------------------------
  1224 
  1225 *** General ***
  1226 
  1227 * More uniform information about legacy features, notably a
  1228 warning/error of "Legacy feature: ...", depending on the state of the
  1229 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1230 legacy features will disappear eventually.
  1231 
  1232 * Theory syntax: the header format ``theory A = B + C:'' has been
  1233 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1234 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1235 
  1236 * Theory syntax: the old non-Isar theory file format has been
  1237 discontinued altogether.  Note that ML proof scripts may still be used
  1238 with Isar theories; migration is usually quite simple with the ML
  1239 function use_legacy_bindings.  INCOMPATIBILITY.
  1240 
  1241 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1242 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1243 quotes.
  1244 
  1245 * Theory loader: be more serious about observing the static theory
  1246 header specifications (including optional directories), but not the
  1247 accidental file locations of previously successful loads.  The strict
  1248 update policy of former update_thy is now already performed by
  1249 use_thy, so the former has been removed; use_thys updates several
  1250 theories simultaneously, just as 'imports' within a theory header
  1251 specification, but without merging the results.  Potential
  1252 INCOMPATIBILITY: may need to refine theory headers and commands
  1253 ROOT.ML which depend on load order.
  1254 
  1255 * Theory loader: optional support for content-based file
  1256 identification, instead of the traditional scheme of full physical
  1257 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1258 (cf. the system manual).  The new scheme allows to work with
  1259 non-finished theories in persistent session images, such that source
  1260 files may be moved later on without requiring reloads.
  1261 
  1262 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1263 file (with the same base name as the theory) are considered a legacy
  1264 feature, which will disappear eventually. Even now, the theory loader
  1265 no longer maintains dependencies on such files.
  1266 
  1267 * Syntax: the scope for resolving ambiguities via type-inference is
  1268 now limited to individual terms, instead of whole simultaneous
  1269 specifications as before. This greatly reduces the complexity of the
  1270 syntax module and improves flexibility by separating parsing and
  1271 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1272 'fixes' etc.) are required in rare situations.
  1273 
  1274 * Syntax: constants introduced by new-style packages ('definition',
  1275 'abbreviation' etc.) are passed through the syntax module in
  1276 ``authentic mode''. This means that associated mixfix annotations
  1277 really stick to such constants, independently of potential name space
  1278 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1279 trees are represented slightly differently, may need to adapt syntax
  1280 translations accordingly. Use CONST marker in 'translations' and
  1281 @{const_syntax} antiquotation in 'parse_translation' etc.
  1282 
  1283 * Legacy goal package: reduced interface to the bare minimum required
  1284 to keep existing proof scripts running.  Most other user-level
  1285 functions are now part of the OldGoals structure, which is *not* open
  1286 by default (consider isatool expandshort before open OldGoals).
  1287 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1288 these tend to cause confusion about the actual goal (!) context being
  1289 used here, which is not necessarily the same as the_context().
  1290 
  1291 * Command 'find_theorems': supports "*" wild-card in "name:"
  1292 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1293 support a specific search form (see ProofGeneral/CHANGES).
  1294 
  1295 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1296 by default, which means that "prems" (and also "fixed variables") are
  1297 suppressed from proof state output.  Note that the ProofGeneral
  1298 settings mechanism allows to change and save options persistently, but
  1299 older versions of Isabelle will fail to start up if a negative prems
  1300 limit is imposed.
  1301 
  1302 * Local theory targets may be specified by non-nested blocks of
  1303 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1304 contain definitions, theorems etc., including any derived mechanism
  1305 that has been implemented on top of these primitives.  This concept
  1306 generalizes the existing ``theorem (in ...)'' towards more versatility
  1307 and scalability.
  1308 
  1309 * Proof General interface: proper undo of final 'end' command;
  1310 discontinued Isabelle/classic mode (ML proof scripts).
  1311 
  1312 
  1313 *** Document preparation ***
  1314 
  1315 * Added antiquotation @{theory name} which prints the given name,
  1316 after checking that it refers to a valid ancestor theory in the
  1317 current context.
  1318 
  1319 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1320 check the given source text as ML type/structure, printing verbatim.
  1321 
  1322 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1323 "c args == rhs" given in the current context.  (Any number of
  1324 arguments may be given on the LHS.)
  1325 
  1326 
  1327 *** Pure ***
  1328 
  1329 * The 'class' package offers a combination of axclass and locale to
  1330 achieve Haskell-like type classes in Isabelle.  Definitions and
  1331 theorems within a class context produce both relative results (with
  1332 implicit parameters according to the locale context), and polymorphic
  1333 constants with qualified polymorphism (according to the class
  1334 context).  Within the body context of a 'class' target, a separate
  1335 syntax layer ("user space type system") takes care of converting
  1336 between global polymorphic consts and internal locale representation.
  1337 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1338 "isatool doc classes" provides a tutorial.
  1339 
  1340 * Generic code generator framework allows to generate executable
  1341 code for ML and Haskell (including Isabelle classes).  A short usage
  1342 sketch:
  1343 
  1344     internal compilation:
  1345         export_code <list of constants (term syntax)> in SML
  1346     writing SML code to a file:
  1347         export_code <list of constants (term syntax)> in SML <filename>
  1348     writing OCaml code to a file:
  1349         export_code <list of constants (term syntax)> in OCaml <filename>
  1350     writing Haskell code to a bunch of files:
  1351         export_code <list of constants (term syntax)> in Haskell <filename>
  1352 
  1353     evaluating closed propositions to True/False using code generation:
  1354         method ``eval''
  1355 
  1356 Reasonable default setup of framework in HOL.
  1357 
  1358 Theorem attributs for selecting and transforming function equations theorems:
  1359 
  1360     [code fun]:        select a theorem as function equation for a specific constant
  1361     [code fun del]:    deselect a theorem as function equation for a specific constant
  1362     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1363     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1364 
  1365 User-defined serializations (target in {SML, OCaml, Haskell}):
  1366 
  1367     code_const <and-list of constants (term syntax)>
  1368       {(target) <and-list of const target syntax>}+
  1369 
  1370     code_type <and-list of type constructors>
  1371       {(target) <and-list of type target syntax>}+
  1372 
  1373     code_instance <and-list of instances>
  1374       {(target)}+
  1375         where instance ::= <type constructor> :: <class>
  1376 
  1377     code_class <and_list of classes>
  1378       {(target) <and-list of class target syntax>}+
  1379         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1380 
  1381 code_instance and code_class only are effective to target Haskell.
  1382 
  1383 For example usage see src/HOL/ex/Codegenerator.thy and
  1384 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1385 generation from Isabelle/HOL theories is available via "isatool doc
  1386 codegen".
  1387 
  1388 * Code generator: consts in 'consts_code' Isar commands are now
  1389 referred to by usual term syntax (including optional type
  1390 annotations).
  1391 
  1392 * Command 'no_translations' removes translation rules from theory
  1393 syntax.
  1394 
  1395 * Overloaded definitions are now actually checked for acyclic
  1396 dependencies.  The overloading scheme is slightly more general than
  1397 that of Haskell98, although Isabelle does not demand an exact
  1398 correspondence to type class and instance declarations.
  1399 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1400 exotic versions of overloading -- at the discretion of the user!
  1401 
  1402 Polymorphic constants are represented via type arguments, i.e. the
  1403 instantiation that matches an instance against the most general
  1404 declaration given in the signature.  For example, with the declaration
  1405 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1406 as c(nat).  Overloading is essentially simultaneous structural
  1407 recursion over such type arguments.  Incomplete specification patterns
  1408 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1409 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1410 Command 'print_theory' outputs the normalized system of recursive
  1411 equations, see section "definitions".
  1412 
  1413 * Configuration options are maintained within the theory or proof
  1414 context (with name and type bool/int/string), providing a very simple
  1415 interface to a poor-man's version of general context data.  Tools may
  1416 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1417 these values using Config.get etc.  Users may change options via an
  1418 associated attribute of the same name.  This form of context
  1419 declaration works particularly well with commands 'declare' or
  1420 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1421 very easy to avoid global references, which would not observe Isar
  1422 toplevel undo/redo and fail to work with multithreading.
  1423 
  1424 Various global ML references of Pure and HOL have been turned into
  1425 configuration options:
  1426 
  1427   Unify.search_bound		unify_search_bound
  1428   Unify.trace_bound		unify_trace_bound
  1429   Unify.trace_simp		unify_trace_simp
  1430   Unify.trace_types		unify_trace_types
  1431   Simplifier.simp_depth_limit	simp_depth_limit
  1432   Blast.depth_limit		blast_depth_limit
  1433   DatatypeProp.dtK		datatype_distinctness_limit
  1434   fast_arith_neq_limit  	fast_arith_neq_limit
  1435   fast_arith_split_limit	fast_arith_split_limit
  1436 
  1437 * Named collections of theorems may be easily installed as context
  1438 data using the functor NamedThmsFun (see also
  1439 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1440 attributes; there is also a toplevel print command.  This facility is
  1441 just a common case of general context data, which is the preferred way
  1442 for anything more complex than just a list of facts in canonical
  1443 order.
  1444 
  1445 * Isar: command 'declaration' augments a local theory by generic
  1446 declaration functions written in ML.  This enables arbitrary content
  1447 being added to the context, depending on a morphism that tells the
  1448 difference of the original declaration context wrt. the application
  1449 context encountered later on.
  1450 
  1451 * Isar: proper interfaces for simplification procedures.  Command
  1452 'simproc_setup' declares named simprocs (with match patterns, and body
  1453 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1454 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1455 
  1456 * Isar: an extra pair of brackets around attribute declarations
  1457 abbreviates a theorem reference involving an internal dummy fact,
  1458 which will be ignored later --- only the effect of the attribute on
  1459 the background context will persist.  This form of in-place
  1460 declarations is particularly useful with commands like 'declare' and
  1461 'using', for example ``have A using [[simproc a]] by simp''.
  1462 
  1463 * Isar: method "assumption" (and implicit closing of subproofs) now
  1464 takes simple non-atomic goal assumptions into account: after applying
  1465 an assumption as a rule the resulting subgoals are solved by atomic
  1466 assumption steps.  This is particularly useful to finish 'obtain'
  1467 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1468 without referring to the original premise "!!x. P x ==> thesis" in the
  1469 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1470 more permissive.
  1471 
  1472 * Isar: implicit use of prems from the Isar proof context is
  1473 considered a legacy feature.  Common applications like ``have A .''
  1474 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1475 referencing facts explicitly here improves readability and
  1476 maintainability of proof texts.
  1477 
  1478 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1479 the obtained context from the course of reasoning!  For example:
  1480 
  1481   assume "EX x y. A x & B y"   -- "any previous fact"
  1482   then guess x and y by clarify
  1483 
  1484 This technique is potentially adventurous, depending on the facts and
  1485 proof tools being involved here.
  1486 
  1487 * Isar: known facts from the proof context may be specified as literal
  1488 propositions, using ASCII back-quote syntax.  This works wherever
  1489 named facts used to be allowed so far, in proof commands, proof
  1490 methods, attributes etc.  Literal facts are retrieved from the context
  1491 according to unification of type and term parameters.  For example,
  1492 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1493 theorems in the current context, then these are valid literal facts:
  1494 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1495 
  1496 There is also a proof method "fact" which does the same composition
  1497 for explicit goal states, e.g. the following proof texts coincide with
  1498 certain special cases of literal facts:
  1499 
  1500   have "A" by fact                 ==  note `A`
  1501   have "A ==> B" by fact           ==  note `A ==> B`
  1502   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1503   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1504 
  1505 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1506 outer syntax.  Thus symbolic identifiers may be used without
  1507 additional white space in declarations like this: ``assume *: A''.
  1508 
  1509 * Isar: 'print_facts' prints all local facts of the current context,
  1510 both named and unnamed ones.
  1511 
  1512 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1513 
  1514   def x == "t" and y == "u"
  1515 
  1516 * Isar: added command 'unfolding', which is structurally similar to
  1517 'using', but affects both the goal state and facts by unfolding given
  1518 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1519 'unfolded' attribute may be replaced by first-class proof text.
  1520 
  1521 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1522 and command 'unfolding' now all support object-level equalities
  1523 (potentially conditional).  The underlying notion of rewrite rule is
  1524 analogous to the 'rule_format' attribute, but *not* that of the
  1525 Simplifier (which is usually more generous).
  1526 
  1527 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1528 premises of a theorem by n. Useful in conjunction with drule.
  1529 
  1530 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1531 method expression within a sandbox consisting of the first N
  1532 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1533 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1534 simplifies all new goals that emerge from applying rule foo to the
  1535 originally first one.
  1536 
  1537 * Isar: schematic goals are no longer restricted to higher-order
  1538 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1539 expected.
  1540 
  1541 * Isar: the conclusion of a long theorem statement is now either
  1542 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1543 (essentially a disjunction of cases with local parameters and
  1544 assumptions).  The latter allows to express general elimination rules
  1545 adequately; in this notation common elimination rules look like this:
  1546 
  1547   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1548     assumes "EX x. P x"
  1549     obtains x where "P x"
  1550 
  1551   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1552     assumes "A & B"
  1553     obtains A and B
  1554 
  1555   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1556     assumes "A | B"
  1557     obtains
  1558       A
  1559     | B
  1560 
  1561 The subsequent classical rules even refer to the formal "thesis"
  1562 explicitly:
  1563 
  1564   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1565     obtains "~ thesis"
  1566 
  1567   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1568     obtains "thesis ==> something"
  1569 
  1570 The actual proof of an 'obtains' statement is analogous to that of the
  1571 Isar proof element 'obtain', only that there may be several cases.
  1572 Optional case names may be specified in parentheses; these will be
  1573 available both in the present proof and as annotations in the
  1574 resulting rule, for later use with the 'cases' method (cf. attribute
  1575 case_names).
  1576 
  1577 * Isar: the assumptions of a long theorem statement are available as
  1578 "assms" fact in the proof context.  This is more appropriate than the
  1579 (historical) "prems", which refers to all assumptions of the current
  1580 context, including those from the target locale, proof body etc.
  1581 
  1582 * Isar: 'print_statement' prints theorems from the current theory or
  1583 proof context in long statement form, according to the syntax of a
  1584 top-level lemma.
  1585 
  1586 * Isar: 'obtain' takes an optional case name for the local context
  1587 introduction rule (default "that").
  1588 
  1589 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1590 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1591 to occur.
  1592 
  1593 * Pure: syntax "CONST name" produces a fully internalized constant
  1594 according to the current context.  This is particularly useful for
  1595 syntax translations that should refer to internal constant
  1596 representations independently of name spaces.
  1597 
  1598 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1599 instead of "FOO ". This allows multiple binder declarations to coexist
  1600 in the same context.  INCOMPATIBILITY.
  1601 
  1602 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1603 primitive that also works in a locale context (both for constants and
  1604 fixed variables). Type declaration and internal syntactic representation
  1605 of given constants retrieved from the context. Likewise, the
  1606 'no_notation' command allows to remove given syntax annotations from the
  1607 current context.
  1608 
  1609 * Isar/locales: new derived specification elements 'axiomatization',
  1610 'definition', 'abbreviation', which support type-inference, admit
  1611 object-level specifications (equality, equivalence).  See also the
  1612 isar-ref manual.  Examples:
  1613 
  1614   axiomatization
  1615     eq  (infix "===" 50) where
  1616     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1617 
  1618   definition "f x y = x + y + 1"
  1619   definition g where "g x = f x x"
  1620 
  1621   abbreviation
  1622     neq  (infix "=!=" 50) where
  1623     "x =!= y == ~ (x === y)"
  1624 
  1625 These specifications may be also used in a locale context.  Then the
  1626 constants being introduced depend on certain fixed parameters, and the
  1627 constant name is qualified by the locale base name.  An internal
  1628 abbreviation takes care for convenient input and output, making the
  1629 parameters implicit and using the original short name.  See also
  1630 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1631 entities from a monomorphic theory.
  1632 
  1633 Presently, abbreviations are only available 'in' a target locale, but
  1634 not inherited by general import expressions.  Also note that
  1635 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1636 'translations' in common applications.  The "no_abbrevs" print mode
  1637 prevents folding of abbreviations in term output.
  1638 
  1639 Concrete syntax is attached to specified constants in internal form,
  1640 independently of name spaces.  The parse tree representation is
  1641 slightly different -- use 'notation' instead of raw 'syntax', and
  1642 'translations' with explicit "CONST" markup to accommodate this.
  1643 
  1644 * Pure/Isar: unified syntax for new-style specification mechanisms
  1645 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1646 full type inference and dummy patterns ("_").  For example:
  1647 
  1648   definition "K x _ = x"
  1649 
  1650   inductive conj for A B
  1651   where "A ==> B ==> conj A B"
  1652 
  1653 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1654 the current context.  Print mode "no_abbrevs" prevents inversion of
  1655 abbreviations on output.
  1656 
  1657 * Isar/locales: improved parameter handling: use of locales "var" and
  1658 "struct" no longer necessary; - parameter renamings are no longer
  1659 required to be injective.  For example, this allows to define
  1660 endomorphisms as locale endom = homom mult mult h.
  1661 
  1662 * Isar/locales: changed the way locales with predicates are defined.
  1663 Instead of accumulating the specification, the imported expression is
  1664 now an interpretation.  INCOMPATIBILITY: different normal form of
  1665 locale expressions.  In particular, in interpretations of locales with
  1666 predicates, goals repesenting already interpreted fragments are not
  1667 removed automatically.  Use methods `intro_locales' and
  1668 `unfold_locales'; see below.
  1669 
  1670 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1671 provide backward reasoning on locales predicates.  The methods are
  1672 aware of interpretations and discharge corresponding goals.
  1673 `intro_locales' is less aggressive then `unfold_locales' and does not
  1674 unfold predicates to assumptions.
  1675 
  1676 * Isar/locales: the order in which locale fragments are accumulated
  1677 has changed.  This enables to override declarations from fragments due
  1678 to interpretations -- for example, unwanted simp rules.
  1679 
  1680 * Isar/locales: interpretation in theories and proof contexts has been
  1681 extended.  One may now specify (and prove) equations, which are
  1682 unfolded in interpreted theorems.  This is useful for replacing
  1683 defined concepts (constants depending on locale parameters) by
  1684 concepts already existing in the target context.  Example:
  1685 
  1686   interpretation partial_order ["op <= :: [int, int] => bool"]
  1687     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1688 
  1689 Typically, the constant `partial_order.less' is created by a
  1690 definition specification element in the context of locale
  1691 partial_order.
  1692 
  1693 * Method "induct": improved internal context management to support
  1694 local fixes and defines on-the-fly. Thus explicit meta-level
  1695 connectives !!  and ==> are rarely required anymore in inductive goals
  1696 (using object-logic connectives for this purpose has been long
  1697 obsolete anyway). Common proof patterns are explained in
  1698 src/HOL/Induct/Common_Patterns.thy, see also
  1699 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1700 examples.
  1701 
  1702 * Method "induct": improved handling of simultaneous goals. Instead of
  1703 introducing object-level conjunction, the statement is now split into
  1704 several conclusions, while the corresponding symbolic cases are nested
  1705 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1706 see src/HOL/Induct/Common_Patterns.thy, for example.
  1707 
  1708 * Method "induct": mutual induction rules are now specified as a list
  1709 of rule sharing the same induction cases. HOL packages usually provide
  1710 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1711 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1712 mutual induction rules differently, i.e. like this:
  1713 
  1714   (induct rule: foo_bar.inducts)
  1715   (induct set: foo bar)
  1716   (induct pred: foo bar)
  1717   (induct type: foo bar)
  1718 
  1719 The ML function ProjectRule.projections turns old-style rules into the
  1720 new format.
  1721 
  1722 * Method "coinduct": dual of induction, see
  1723 src/HOL/Library/Coinductive_List.thy for various examples.
  1724 
  1725 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1726 considered a legacy feature.
  1727 
  1728 * Attribute "symmetric" produces result with standardized schematic
  1729 variables (index 0).  Potential INCOMPATIBILITY.
  1730 
  1731 * Simplifier: by default the simplifier trace only shows top level
  1732 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1733 default. Thus there is less danger of being flooded by the trace. The
  1734 trace indicates where parts have been suppressed.
  1735   
  1736 * Provers/classical: removed obsolete classical version of elim_format
  1737 attribute; classical elim/dest rules are now treated uniformly when
  1738 manipulating the claset.
  1739 
  1740 * Provers/classical: stricter checks to ensure that supplied intro,
  1741 dest and elim rules are well-formed; dest and elim rules must have at
  1742 least one premise.
  1743 
  1744 * Provers/classical: attributes dest/elim/intro take an optional
  1745 weight argument for the rule (just as the Pure versions).  Weights are
  1746 ignored by automated tools, but determine the search order of single
  1747 rule steps.
  1748 
  1749 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1750 where the body does not mention the bound variable.  Note that dummy
  1751 patterns implicitly depend on their context of bounds, which makes
  1752 "{_. _}" match any set comprehension as expected.  Potential
  1753 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1754 constant "_idtdummy" in the binding position.
  1755 
  1756 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1757 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1758 for example "A -> B" => "Pi A (%_. B)".
  1759 
  1760 * Pure: 'class_deps' command visualizes the subclass relation, using
  1761 the graph browser tool.
  1762 
  1763 * Pure: 'print_theory' now suppresses certain internal declarations by
  1764 default; use '!' option for full details.
  1765 
  1766 
  1767 *** HOL ***
  1768 
  1769 * Method "metis" proves goals by applying the Metis general-purpose
  1770 resolution prover (see also http://gilith.com/software/metis/).
  1771 Examples are in the directory MetisExamples.  WARNING: the
  1772 Isabelle/HOL-Metis integration does not yet work properly with
  1773 multi-threading.
  1774   
  1775 * Command 'sledgehammer' invokes external automatic theorem provers as
  1776 background processes.  It generates calls to the "metis" method if
  1777 successful. These can be pasted into the proof.  Users do not have to
  1778 wait for the automatic provers to return.  WARNING: does not really
  1779 work with multi-threading.
  1780 
  1781 * New "auto_quickcheck" feature tests outermost goal statements for
  1782 potential counter-examples.  Controlled by ML references
  1783 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1784 5000 milliseconds).  Fails silently if statements is outside of
  1785 executable fragment, or any other codgenerator problem occurs.
  1786 
  1787 * New constant "undefined" with axiom "undefined x = undefined".
  1788 
  1789 * Added class "HOL.eq", allowing for code generation with polymorphic
  1790 equality.
  1791 
  1792 * Some renaming of class constants due to canonical name prefixing in
  1793 the new 'class' package:
  1794 
  1795     HOL.abs ~> HOL.abs_class.abs
  1796     HOL.divide ~> HOL.divide_class.divide
  1797     0 ~> HOL.zero_class.zero
  1798     1 ~> HOL.one_class.one
  1799     op + ~> HOL.plus_class.plus
  1800     op - ~> HOL.minus_class.minus
  1801     uminus ~> HOL.minus_class.uminus
  1802     op * ~> HOL.times_class.times
  1803     op < ~> HOL.ord_class.less
  1804     op <= > HOL.ord_class.less_eq
  1805     Nat.power ~> Power.power_class.power
  1806     Nat.size ~> Nat.size_class.size
  1807     Numeral.number_of ~> Numeral.number_class.number_of
  1808     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1809     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1810     Orderings.min ~> Orderings.ord_class.min
  1811     Orderings.max ~> Orderings.ord_class.max
  1812     Divides.op div ~> Divides.div_class.div
  1813     Divides.op mod ~> Divides.div_class.mod
  1814     Divides.op dvd ~> Divides.div_class.dvd
  1815 
  1816 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1817 
  1818 a) User-defined constants using any of the names "plus", "minus",
  1819 "times", "less" or "less_eq". The standard syntax translations for
  1820 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1821 names.
  1822 
  1823 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1824 INCOMPATIBILITY: use more specific names.
  1825 
  1826 c) Permutative equations (e.g. "a + b = b + a")
  1827 Since the change of names also changes the order of terms, permutative
  1828 rewrite rules may get applied in a different order. Experience shows
  1829 that this is rarely the case (only two adaptions in the whole Isabelle
  1830 distribution).  INCOMPATIBILITY: rewrite proofs
  1831 
  1832 d) ML code directly refering to constant names
  1833 This in general only affects hand-written proof tactics, simprocs and
  1834 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1835 Consider using @{const_name} antiquotation.
  1836 
  1837 * New class "default" with associated constant "default".
  1838 
  1839 * Function "sgn" is now overloaded and available on int, real, complex
  1840 (and other numeric types), using class "sgn".  Two possible defs of
  1841 sgn are given as equational assumptions in the classes sgn_if and
  1842 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1843 INCOMPATIBILITY.
  1844 
  1845 * Locale "partial_order" now unified with class "order" (cf. theory
  1846 Orderings), added parameter "less".  INCOMPATIBILITY.
  1847 
  1848 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1849 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1850 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1851 
  1852 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1853 changed order of proof goals in instance proofs.
  1854 
  1855 * The transitivity reasoner for partial and linear orders is set up
  1856 for classes "order" and "linorder".  Instances of the reasoner are available
  1857 in all contexts importing or interpreting the corresponding locales.
  1858 Method "order" invokes the reasoner separately; the reasoner
  1859 is also integrated with the Simplifier as a solver.  Diagnostic
  1860 command 'print_orders' shows the available instances of the reasoner
  1861 in the current context.
  1862 
  1863 * Localized monotonicity predicate in theory "Orderings"; integrated
  1864 lemmas max_of_mono and min_of_mono with this predicate.
  1865 INCOMPATIBILITY.
  1866 
  1867 * Formulation of theorem "dense" changed slightly due to integration
  1868 with new class dense_linear_order.
  1869 
  1870 * Uniform lattice theory development in HOL.
  1871 
  1872     constants "meet" and "join" now named "inf" and "sup"
  1873     constant "Meet" now named "Inf"
  1874 
  1875     classes "meet_semilorder" and "join_semilorder" now named
  1876       "lower_semilattice" and "upper_semilattice"
  1877     class "lorder" now named "lattice"
  1878     class "comp_lat" now named "complete_lattice"
  1879 
  1880     Instantiation of lattice classes allows explicit definitions
  1881     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1882 
  1883   INCOMPATIBILITY.  Theorem renames:
  1884 
  1885     meet_left_le            ~> inf_le1
  1886     meet_right_le           ~> inf_le2
  1887     join_left_le            ~> sup_ge1
  1888     join_right_le           ~> sup_ge2
  1889     meet_join_le            ~> inf_sup_ord
  1890     le_meetI                ~> le_infI
  1891     join_leI                ~> le_supI
  1892     le_meet                 ~> le_inf_iff
  1893     le_join                 ~> ge_sup_conv
  1894     meet_idempotent         ~> inf_idem
  1895     join_idempotent         ~> sup_idem
  1896     meet_comm               ~> inf_commute
  1897     join_comm               ~> sup_commute
  1898     meet_leI1               ~> le_infI1
  1899     meet_leI2               ~> le_infI2
  1900     le_joinI1               ~> le_supI1
  1901     le_joinI2               ~> le_supI2
  1902     meet_assoc              ~> inf_assoc
  1903     join_assoc              ~> sup_assoc
  1904     meet_left_comm          ~> inf_left_commute
  1905     meet_left_idempotent    ~> inf_left_idem
  1906     join_left_comm          ~> sup_left_commute
  1907     join_left_idempotent    ~> sup_left_idem
  1908     meet_aci                ~> inf_aci
  1909     join_aci                ~> sup_aci
  1910     le_def_meet             ~> le_iff_inf
  1911     le_def_join             ~> le_iff_sup
  1912     join_absorp2            ~> sup_absorb2
  1913     join_absorp1            ~> sup_absorb1
  1914     meet_absorp1            ~> inf_absorb1
  1915     meet_absorp2            ~> inf_absorb2
  1916     meet_join_absorp        ~> inf_sup_absorb
  1917     join_meet_absorp        ~> sup_inf_absorb
  1918     distrib_join_le         ~> distrib_sup_le
  1919     distrib_meet_le         ~> distrib_inf_le
  1920 
  1921     add_meet_distrib_left   ~> add_inf_distrib_left
  1922     add_join_distrib_left   ~> add_sup_distrib_left
  1923     is_join_neg_meet        ~> is_join_neg_inf
  1924     is_meet_neg_join        ~> is_meet_neg_sup
  1925     add_meet_distrib_right  ~> add_inf_distrib_right
  1926     add_join_distrib_right  ~> add_sup_distrib_right
  1927     add_meet_join_distribs  ~> add_sup_inf_distribs
  1928     join_eq_neg_meet        ~> sup_eq_neg_inf
  1929     meet_eq_neg_join        ~> inf_eq_neg_sup
  1930     add_eq_meet_join        ~> add_eq_inf_sup
  1931     meet_0_imp_0            ~> inf_0_imp_0
  1932     join_0_imp_0            ~> sup_0_imp_0
  1933     meet_0_eq_0             ~> inf_0_eq_0
  1934     join_0_eq_0             ~> sup_0_eq_0
  1935     neg_meet_eq_join        ~> neg_inf_eq_sup
  1936     neg_join_eq_meet        ~> neg_sup_eq_inf
  1937     join_eq_if              ~> sup_eq_if
  1938 
  1939     mono_meet               ~> mono_inf
  1940     mono_join               ~> mono_sup
  1941     meet_bool_eq            ~> inf_bool_eq
  1942     join_bool_eq            ~> sup_bool_eq
  1943     meet_fun_eq             ~> inf_fun_eq
  1944     join_fun_eq             ~> sup_fun_eq
  1945     meet_set_eq             ~> inf_set_eq
  1946     join_set_eq             ~> sup_set_eq
  1947     meet1_iff               ~> inf1_iff
  1948     meet2_iff               ~> inf2_iff
  1949     meet1I                  ~> inf1I
  1950     meet2I                  ~> inf2I
  1951     meet1D1                 ~> inf1D1
  1952     meet2D1                 ~> inf2D1
  1953     meet1D2                 ~> inf1D2
  1954     meet2D2                 ~> inf2D2
  1955     meet1E                  ~> inf1E
  1956     meet2E                  ~> inf2E
  1957     join1_iff               ~> sup1_iff
  1958     join2_iff               ~> sup2_iff
  1959     join1I1                 ~> sup1I1
  1960     join2I1                 ~> sup2I1
  1961     join1I1                 ~> sup1I1
  1962     join2I2                 ~> sup1I2
  1963     join1CI                 ~> sup1CI
  1964     join2CI                 ~> sup2CI
  1965     join1E                  ~> sup1E
  1966     join2E                  ~> sup2E
  1967 
  1968     is_meet_Meet            ~> is_meet_Inf
  1969     Meet_bool_def           ~> Inf_bool_def
  1970     Meet_fun_def            ~> Inf_fun_def
  1971     Meet_greatest           ~> Inf_greatest
  1972     Meet_lower              ~> Inf_lower
  1973     Meet_set_def            ~> Inf_set_def
  1974 
  1975     Sup_def                 ~> Sup_Inf
  1976     Sup_bool_eq             ~> Sup_bool_def
  1977     Sup_fun_eq              ~> Sup_fun_def
  1978     Sup_set_eq              ~> Sup_set_def
  1979 
  1980     listsp_meetI            ~> listsp_infI
  1981     listsp_meet_eq          ~> listsp_inf_eq
  1982 
  1983     meet_min                ~> inf_min
  1984     join_max                ~> sup_max
  1985 
  1986 * Added syntactic class "size"; overloaded constant "size" now has
  1987 type "'a::size ==> bool"
  1988 
  1989 * Internal reorganisation of `size' of datatypes: size theorems
  1990 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1991 simplification rules by default!); theorems "prod.size" now named
  1992 "*.size".
  1993 
  1994 * Class "div" now inherits from class "times" rather than "type".
  1995 INCOMPATIBILITY.
  1996 
  1997 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1998 Linorder etc.  have disappeared; operations defined in terms of
  1999 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2000 
  2001 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2002 
  2003 * HOL-Word: New extensive library and type for generic, fixed size
  2004 machine words, with arithemtic, bit-wise, shifting and rotating
  2005 operations, reflection into int, nat, and bool lists, automation for
  2006 linear arithmetic (by automatic reflection into nat or int), including
  2007 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2008 arithmetic type classes, supporting automatic simplification of
  2009 numerals on all operations.
  2010 
  2011 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2012 
  2013 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2014 
  2015 * Code generator library theories:
  2016   - Code_Integer represents HOL integers by big integer literals in target
  2017     languages.
  2018   - Code_Char represents HOL characters by character literals in target
  2019     languages.
  2020   - Code_Char_chr like Code_Char, but also offers treatment of character
  2021     codes; includes Code_Integer.
  2022   - Executable_Set allows to generate code for finite sets using lists.
  2023   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2024     denominator).
  2025   - Executable_Real implements a subset of real numbers, namly those
  2026     representable by rational numbers.
  2027   - Efficient_Nat implements natural numbers by integers, which in general will
  2028     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2029     includes Code_Integer.
  2030   - Code_Index provides an additional datatype index which is mapped to
  2031     target-language built-in integers.
  2032   - Code_Message provides an additional datatype message_string which is isomorphic to
  2033     strings; messages are mapped to target-language strings.
  2034 
  2035 * New package for inductive predicates
  2036 
  2037   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2038 
  2039     inductive
  2040       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2041       for z_1 :: U_1 and ... and z_n :: U_m
  2042     where
  2043       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2044     | ...
  2045 
  2046   with full support for type-inference, rather than
  2047 
  2048     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2049 
  2050     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2051     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2052 
  2053     inductive "s z_1 ... z_m"
  2054     intros
  2055       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2056       ...
  2057 
  2058   For backward compatibility, there is a wrapper allowing inductive
  2059   sets to be defined with the new package via
  2060 
  2061     inductive_set
  2062       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2063       for z_1 :: U_1 and ... and z_n :: U_m
  2064     where
  2065       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2066     | ...
  2067 
  2068   or
  2069 
  2070     inductive_set
  2071       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2072       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2073       for z_1 :: U_1 and ... and z_n :: U_m
  2074     where
  2075       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2076     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2077     | ...
  2078 
  2079   if the additional syntax "p ..." is required.
  2080 
  2081   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2082   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2083 
  2084   INCOMPATIBILITIES:
  2085 
  2086   - Since declaration and definition of inductive sets or predicates
  2087     is no longer separated, abbreviations involving the newly
  2088     introduced sets or predicates must be specified together with the
  2089     introduction rules after the 'where' keyword (see above), rather
  2090     than before the actual inductive definition.
  2091 
  2092   - The variables in induction and elimination rules are now
  2093     quantified in the order of their occurrence in the introduction
  2094     rules, rather than in alphabetical order. Since this may break
  2095     some proofs, these proofs either have to be repaired, e.g. by
  2096     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2097     statements of the form
  2098 
  2099       case (rule_i a_i_1 ... a_i_{k_i})
  2100 
  2101     or the old order of quantification has to be restored by explicitly adding
  2102     meta-level quantifiers in the introduction rules, i.e.
  2103 
  2104       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2105 
  2106   - The format of the elimination rules is now
  2107 
  2108       p z_1 ... z_m x_1 ... x_n ==>
  2109         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2110         ==> ... ==> P
  2111 
  2112     for predicates and
  2113 
  2114       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2115         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2116         ==> ... ==> P
  2117 
  2118     for sets rather than
  2119 
  2120       x : s z_1 ... z_m ==>
  2121         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2122         ==> ... ==> P
  2123 
  2124     This may require terms in goals to be expanded to n-tuples
  2125     (e.g. using case_tac or simplification with the split_paired_all
  2126     rule) before the above elimination rule is applicable.
  2127 
  2128   - The elimination or case analysis rules for (mutually) inductive
  2129     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2130     list of rules "p_1_..._p_k.elims" is no longer available.
  2131 
  2132 * New package "function"/"fun" for general recursive functions,
  2133 supporting mutual and nested recursion, definitions in local contexts,
  2134 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2135 for small examples, and the separate tutorial on the function
  2136 package. The old recdef "package" is still available as before, but
  2137 users are encouraged to use the new package.
  2138 
  2139 * Method "lexicographic_order" automatically synthesizes termination
  2140 relations as lexicographic combinations of size measures. 
  2141 
  2142 * Case-expressions allow arbitrary constructor-patterns (including
  2143 "_") and take their order into account, like in functional
  2144 programming.  Internally, this is translated into nested
  2145 case-expressions; missing cases are added and mapped to the predefined
  2146 constant "undefined". In complicated cases printing may no longer show
  2147 the original input but the internal form. Lambda-abstractions allow
  2148 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2149 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2150 variable.
  2151 
  2152 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2153 is an abbreviation for "of_nat :: nat => int". The simplification
  2154 rules for "of_nat" have been changed to work like "int" did
  2155 previously.  Potential INCOMPATIBILITY:
  2156   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2157   - of_nat_diff and of_nat_mult are no longer default simp rules
  2158 
  2159 * Method "algebra" solves polynomial equations over (semi)rings using
  2160 Groebner bases. The (semi)ring structure is defined by locales and the
  2161 tool setup depends on that generic context. Installing the method for
  2162 a specific type involves instantiating the locale and possibly adding
  2163 declarations for computation on the coefficients.  The method is
  2164 already instantiated for natural numbers and for the axiomatic class
  2165 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2166 CALCULEMUS 2007 for the general principles underlying this
  2167 architecture of context-aware proof-tools.
  2168 
  2169 * Method "ferrack" implements quantifier elimination over
  2170 special-purpose dense linear orders using locales (analogous to
  2171 "algebra"). The method is already installed for class
  2172 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2173 rat, etc.
  2174 
  2175 * Former constant "List.op @" now named "List.append".  Use ML
  2176 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2177 circumvent possible incompatibilities when working on ML level.
  2178 
  2179 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2180 
  2181 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2182 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2183 
  2184 * New syntax for Haskell-like list comprehension (input only), eg.
  2185 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2186 
  2187 * The special syntax for function "filter" has changed from [x :
  2188 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2189 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2190 
  2191 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2192 defined on nat only, as an abbreviation for [a..<Suc b]
  2193 INCOMPATIBILITY.
  2194 
  2195 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2196 
  2197 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2198 
  2199 * New lemma collection field_simps (an extension of ring_simps) for
  2200 manipulating (in)equations involving division. Multiplies with all
  2201 denominators that can be proved to be non-zero (in equations) or
  2202 positive/negative (in inequations).
  2203 
  2204 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2205 have been improved and renamed to ring_simps, group_simps and
  2206 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2207 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2208 
  2209 * Theory Library/Commutative_Ring: switched from recdef to function
  2210 package; constants add, mul, pow now curried.  Infix syntax for
  2211 algebraic operations.
  2212 
  2213 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2214 INCOMPATIBILITY.
  2215 
  2216 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2217 INCOMPATIBILITY.
  2218 
  2219 * HOL/records: generalised field-update to take a function on the
  2220 field rather than the new value: r(|A := x|) is translated to A_update
  2221 (K x) r The K-combinator that is internally used is called K_record.
  2222 INCOMPATIBILITY: Usage of the plain update functions has to be
  2223 adapted.
  2224  
  2225 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2226 * x = 0, which are required for a semiring.  Richer structures do not
  2227 inherit from semiring_0 anymore, because this property is a theorem
  2228 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2229 there is more to prove, but this is mostly trivial.
  2230 
  2231 * Class "recpower" is generalized to arbitrary monoids, not just
  2232 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2233 commutativity or semiring properties additionally.
  2234 
  2235 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2236 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2237 better use 'abbreviation'.
  2238 
  2239 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2240 
  2241 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2242 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2243 significant changes for setting up numeral syntax for types:
  2244   - New constants Numeral.pred and Numeral.succ instead
  2245       of former Numeral.bin_pred and Numeral.bin_succ.
  2246   - Use integer operations instead of bin_add, bin_mult and so on.
  2247   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2248   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2249 
  2250 See src/HOL/Integ/IntArith.thy for an example setup.
  2251 
  2252 * Command 'normal_form' computes the normal form of a term that may
  2253 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2254 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2255 heavy-duty computations because the functions are compiled to ML
  2256 first.  Correspondingly, a method "normalization" is provided.  See
  2257 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2258 
  2259 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2260 25 like -->); output depends on the "iff" print_mode, the default is
  2261 "A = B" (with priority 50).
  2262 
  2263 * Relations less (<) and less_eq (<=) are also available on type bool.
  2264 Modified syntax to disallow nesting without explicit parentheses,
  2265 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2266 INCOMPATIBILITY.
  2267 
  2268 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2269 
  2270 * Relation composition operator "op O" now has precedence 75 and binds
  2271 stronger than union and intersection. INCOMPATIBILITY.
  2272 
  2273 * The old set interval syntax "{m..n(}" (and relatives) has been
  2274 removed.  Use "{m..<n}" (and relatives) instead.
  2275 
  2276 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2277 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2278 ``declare [[simproc del: neq]]''.
  2279 
  2280 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2281 True/False.
  2282 
  2283 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2284 
  2285 * Theorem setsum_mult renamed to setsum_right_distrib.
  2286 
  2287 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2288 ``rule'' method.
  2289 
  2290 * Reimplemented methods "sat" and "satx", with several improvements:
  2291 goals no longer need to be stated as "<prems> ==> False", equivalences
  2292 (i.e. "=" on type bool) are handled, variable names of the form
  2293 "lit_<n>" are no longer reserved, significant speedup.
  2294 
  2295 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2296 zChaff is still supported as well.
  2297 
  2298 * 'inductive' and 'datatype': provide projections of mutual rules,
  2299 bundled as foo_bar.inducts;
  2300 
  2301 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2302 Library.
  2303 
  2304 * Library: moved theory Accessible_Part to main HOL.
  2305 
  2306 * Library: added theory Coinductive_List of potentially infinite lists
  2307 as greatest fixed-point.
  2308 
  2309 * Library: added theory AssocList which implements (finite) maps as
  2310 association lists.
  2311 
  2312 * Method "evaluation" solves goals (i.e. a boolean expression)
  2313 efficiently by compiling it to ML.  The goal is "proved" (via an
  2314 oracle) if it evaluates to True.
  2315 
  2316 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2317 also when invoked by the simplifier.  This results in the Simplifier
  2318 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2319 Configuration option fast_arith_split_limit=0 recovers the old
  2320 behavior.
  2321 
  2322 * Support for hex (0x20) and binary (0b1001) numerals.
  2323 
  2324 * New method: reify eqs (t), where eqs are equations for an
  2325 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2326 parameter, computes a term s::'b and a list xs::'a list and proves the
  2327 theorem I xs s = t. This is also known as reification or quoting. The
  2328 resulting theorem is applied to the subgoal to substitute t with I xs
  2329 s.  If t is omitted, the subgoal itself is reified.
  2330 
  2331 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2332 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2333 where f is supposed to be a computable function (in the sense of code
  2334 generattion). The method uses reify to compute s and xs as above then
  2335 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2336 r and finally gets the theorem t = r, which is again applied to the
  2337 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2338 
  2339 * Reflection: Automatic reification now handels binding, an example is
  2340 available in src/HOL/ex/ReflectionEx.thy
  2341 
  2342 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2343 command 'statespace' that is similar to 'record', but introduces an
  2344 abstract specification based on the locale infrastructure instead of
  2345 HOL types.  This leads to extra flexibility in composing state spaces,
  2346 in particular multiple inheritance and renaming of components.
  2347 
  2348 
  2349 *** HOL-Complex ***
  2350 
  2351 * Hyperreal: Functions root and sqrt are now defined on negative real
  2352 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2353 Nonnegativity side conditions have been removed from many lemmas, so
  2354 that more subgoals may now be solved by simplification; potential
  2355 INCOMPATIBILITY.
  2356 
  2357 * Real: new type classes formalize real normed vector spaces and
  2358 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2359 and norm :: 'a => real.
  2360 
  2361 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2362 reals into other types. The overloaded constant Reals :: 'a set is now
  2363 defined as range of_real; potential INCOMPATIBILITY.
  2364 
  2365 * Real: proper support for ML code generation, including 'quickcheck'.
  2366 Reals are implemented as arbitrary precision rationals.
  2367 
  2368 * Hyperreal: Several constants that previously worked only for the
  2369 reals have been generalized, so they now work over arbitrary vector
  2370 spaces. Type annotations may need to be added in some cases; potential
  2371 INCOMPATIBILITY.
  2372 
  2373   Infinitesimal  :: ('a::real_normed_vector) star set
  2374   HFinite        :: ('a::real_normed_vector) star set
  2375   HInfinite      :: ('a::real_normed_vector) star set
  2376   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2377   monad          :: ('a::real_normed_vector) star => 'a star set
  2378   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2379   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2380   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2381   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2382   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2383   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2384   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2385   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2386   sgn            :: 'a::real_normed_vector => 'a
  2387   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2388 
  2389 * Complex: Some complex-specific constants are now abbreviations for
  2390 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2391 hnorm.  Other constants have been entirely removed in favor of the
  2392 polymorphic versions (INCOMPATIBILITY):
  2393 
  2394   approx        <-- capprox
  2395   HFinite       <-- CFinite
  2396   HInfinite     <-- CInfinite
  2397   Infinitesimal <-- CInfinitesimal
  2398   monad         <-- cmonad
  2399   galaxy        <-- cgalaxy
  2400   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2401   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2402   (ns)deriv     <-- (ns)cderiv
  2403 
  2404 
  2405 *** HOL-Algebra ***
  2406 
  2407 * Formalisation of ideals and the quotient construction over rings.
  2408 
  2409 * Order and lattice theory no longer based on records.
  2410 INCOMPATIBILITY.
  2411 
  2412 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2413 greatest_closed.  INCOMPATIBILITY.
  2414 
  2415 * Method algebra is now set up via an attribute.  For examples see
  2416 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2417 of algebraic structures.
  2418 
  2419 * Renamed theory CRing to Ring.
  2420 
  2421 
  2422 *** HOL-Nominal ***
  2423 
  2424 * Substantial, yet incomplete support for nominal datatypes (binding
  2425 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2426 src/HOL/Nominal/Examples.  Prospective users should consult
  2427 http://isabelle.in.tum.de/nominal/
  2428 
  2429 
  2430 *** ML ***
  2431 
  2432 * ML basics: just one true type int, which coincides with IntInf.int
  2433 (even on SML/NJ).
  2434 
  2435 * ML within Isar: antiquotations allow to embed statically-checked
  2436 formal entities in the source, referring to the context available at
  2437 compile-time.  For example:
  2438 
  2439 ML {* @{sort "{zero,one}"} *}
  2440 ML {* @{typ "'a => 'b"} *}
  2441 ML {* @{term "%x. x"} *}
  2442 ML {* @{prop "x == y"} *}
  2443 ML {* @{ctyp "'a => 'b"} *}
  2444 ML {* @{cterm "%x. x"} *}
  2445 ML {* @{cprop "x == y"} *}
  2446 ML {* @{thm asm_rl} *}
  2447 ML {* @{thms asm_rl} *}
  2448 ML {* @{type_name c} *}
  2449 ML {* @{type_syntax c} *}
  2450 ML {* @{const_name c} *}
  2451 ML {* @{const_syntax c} *}
  2452 ML {* @{context} *}
  2453 ML {* @{theory} *}
  2454 ML {* @{theory Pure} *}
  2455 ML {* @{theory_ref} *}
  2456 ML {* @{theory_ref Pure} *}
  2457 ML {* @{simpset} *}
  2458 ML {* @{claset} *}
  2459 ML {* @{clasimpset} *}
  2460 
  2461 The same works for sources being ``used'' within an Isar context.
  2462 
  2463 * ML in Isar: improved error reporting; extra verbosity with
  2464 ML_Context.trace enabled.
  2465 
  2466 * Pure/General/table.ML: the join operations now works via exceptions
  2467 DUP/SAME instead of type option. This is simpler in simple cases, and
  2468 admits slightly more efficient complex applications.
  2469 
  2470 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2471 use Context.generic instead of just theory.
  2472 
  2473 * Pure: datatype Context.generic joins theory/Proof.context and
  2474 provides some facilities for code that works in either kind of
  2475 context, notably GenericDataFun for uniform theory and proof data.
  2476 
  2477 * Pure: simplified internal attribute type, which is now always
  2478 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2479 local (Proof.context) attributes have been discontinued, while
  2480 minimizing code duplication. Thm.rule_attribute and
  2481 Thm.declaration_attribute build canonical attributes; see also structure
  2482 Context for further operations on Context.generic, notably
  2483 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2484 declarations and definitions.
  2485 
  2486 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2487 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2488 init only required for impure data. INCOMPATIBILITY: empty really need
  2489 to be empty (no dependencies on theory content!)
  2490 
  2491 * Pure/kernel: consts certification ignores sort constraints given in
  2492 signature declarations. (This information is not relevant to the
  2493 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2494 potential INCOMPATIBILITY.
  2495 
  2496 * Pure: axiomatic type classes are now purely definitional, with
  2497 explicit proofs of class axioms and super class relations performed
  2498 internally. See Pure/axclass.ML for the main internal interfaces --
  2499 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2500 AxClass.axiomatize_class/classrel/arity supersede
  2501 Sign.add_classes/classrel/arities.
  2502 
  2503 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2504 global/local versions on theory vs. Proof.context have been
  2505 discontinued; Attrib.syntax and Method.syntax have been adapted
  2506 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2507 attributes, methods, etc.
  2508 
  2509 * Pure: several functions of signature "... -> theory -> theory * ..."
  2510 have been reoriented to "... -> theory -> ... * theory" in order to
  2511 allow natural usage in combination with the ||>, ||>>, |-> and
  2512 fold_map combinators.
  2513 
  2514 * Pure: official theorem names (closed derivations) and additional
  2515 comments (tags) are now strictly separate.  Name hints -- which are
  2516 maintained as tags -- may be attached any time without affecting the
  2517 derivation.
  2518 
  2519 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2520 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2521 achieve the old behaviour.
  2522 
  2523 * Pure: the "Goal" constant is now called "prop", supporting a
  2524 slightly more general idea of ``protecting'' meta-level rule
  2525 statements.
  2526 
  2527 * Pure: Logic.(un)varify only works in a global context, which is now
  2528 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2529 Logic.legacy_(un)varify as temporary workaround.
  2530 
  2531 * Pure: structure Name provides scalable operations for generating
  2532 internal variable names, notably Name.variants etc.  This replaces
  2533 some popular functions from term.ML:
  2534 
  2535   Term.variant		->  Name.variant
  2536   Term.variantlist	->  Name.variant_list
  2537   Term.invent_names	->  Name.invent_list
  2538 
  2539 Note that low-level renaming rarely occurs in new code -- operations
  2540 from structure Variable are used instead (see below).
  2541 
  2542 * Pure: structure Variable provides fundamental operations for proper
  2543 treatment of fixed/schematic variables in a context.  For example,
  2544 Variable.import introduces fixes for schematics of given facts and
  2545 Variable.export reverses the effect (up to renaming) -- this replaces
  2546 various freeze_thaw operations.
  2547 
  2548 * Pure: structure Goal provides simple interfaces for
  2549 init/conclude/finish and tactical prove operations (replacing former
  2550 Tactic.prove).  Goal.prove is the canonical way to prove results
  2551 within a given context; Goal.prove_global is a degraded version for
  2552 theory level goals, including a global Drule.standard.  Note that
  2553 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2554 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2555 in a locale context).
  2556 
  2557 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2558 and type checking (Syntax.check_term etc.), with common combinations
  2559 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2560 which are considered legacy and await removal.
  2561 
  2562 * Pure/Syntax: generic interfaces for type unchecking
  2563 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2564 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2565 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2566 available for convenience, but refer to the very same operations using
  2567 a mere theory instead of a full context.
  2568 
  2569 * Isar: simplified treatment of user-level errors, using exception
  2570 ERROR of string uniformly.  Function error now merely raises ERROR,
  2571 without any side effect on output channels.  The Isar toplevel takes
  2572 care of proper display of ERROR exceptions.  ML code may use plain
  2573 handle/can/try; cat_error may be used to concatenate errors like this:
  2574 
  2575   ... handle ERROR msg => cat_error msg "..."
  2576 
  2577 Toplevel ML code (run directly or through the Isar toplevel) may be
  2578 embedded into the Isar toplevel with exception display/debug like
  2579 this:
  2580 
  2581   Isar.toplevel (fn () => ...)
  2582 
  2583 INCOMPATIBILITY, removed special transform_error facilities, removed
  2584 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2585 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2586 -- use plain ERROR instead.
  2587 
  2588 * Isar: theory setup now has type (theory -> theory), instead of a
  2589 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2590 
  2591 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2592 ProofContext.debug/verbose flags.
  2593 
  2594 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2595 theory before entering a proof state.  Transactions now always see a
  2596 quasi-functional intermediate checkpoint, both in interactive and
  2597 batch mode.
  2598 
  2599 * Isar: simplified interfaces for outer syntax.  Renamed
  2600 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2601 OuterSyntax.add_parsers -- this functionality is now included in
  2602 OuterSyntax.command etc.  INCOMPATIBILITY.
  2603 
  2604 * Simplifier: the simpset of a running simplification process now
  2605 contains a proof context (cf. Simplifier.the_context), which is the
  2606 very context that the initial simpset has been retrieved from (by
  2607 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2608 (solver, looper etc.) may depend on arbitrary proof data.
  2609 
  2610 * Simplifier.inherit_context inherits the proof context (plus the
  2611 local bounds) of the current simplification process; any simproc
  2612 etc. that calls the Simplifier recursively should do this!  Removed
  2613 former Simplifier.inherit_bounds, which is already included here --
  2614 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2615 specify an explicit context using Simplifier.context/theory_context.
  2616 
  2617 * Simplifier/Classical Reasoner: more abstract interfaces
  2618 change_simpset/claset for modifying the simpset/claset reference of a
  2619 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2620 INCOMPATIBILITY.
  2621 
  2622 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2623 "Trueprop" etc.
  2624 
  2625 
  2626 *** System ***
  2627 
  2628 * settings: the default heap location within ISABELLE_HOME_USER now
  2629 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2630 Isabelle installations.
  2631 
  2632 * isabelle-process: option -S (secure mode) disables some critical
  2633 operations, notably runtime compilation and evaluation of ML source
  2634 code.
  2635 
  2636 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2637 
  2638 * Support for parallel execution, using native multicore support of
  2639 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2640 independent theories, according to the given theory header
  2641 specifications. The maximum number of worker threads is specified via
  2642 usedir option -M or the "max-threads" setting in Proof General. A
  2643 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2644 to 6 on a 8-core machine.  User-code needs to observe certain
  2645 guidelines for thread-safe programming, see appendix A in the Isar
  2646 Implementation manual.
  2647 
  2648 
  2649 
  2650 New in Isabelle2005 (October 2005)
  2651 ----------------------------------
  2652 
  2653 *** General ***
  2654 
  2655 * Theory headers: the new header syntax for Isar theories is
  2656 
  2657   theory <name>
  2658   imports <theory1> ... <theoryN>
  2659   uses <file1> ... <fileM>
  2660   begin
  2661 
  2662 where the 'uses' part is optional.  The previous syntax
  2663 
  2664   theory <name> = <theory1> + ... + <theoryN>:
  2665 
  2666 will disappear in the next release.  Use isatool fixheaders to convert
  2667 existing theory files.  Note that there is no change in ancient
  2668 non-Isar theories now, but these will disappear soon.
  2669 
  2670 * Theory loader: parent theories can now also be referred to via
  2671 relative and absolute paths.
  2672 
  2673 * Command 'find_theorems' searches for a list of criteria instead of a
  2674 list of constants. Known criteria are: intro, elim, dest, name:string,
  2675 simp:term, and any term. Criteria can be preceded by '-' to select
  2676 theorems that do not match. Intro, elim, dest select theorems that
  2677 match the current goal, name:s selects theorems whose fully qualified
  2678 name contain s, and simp:term selects all simplification rules whose
  2679 lhs match term.  Any other term is interpreted as pattern and selects
  2680 all theorems matching the pattern. Available in ProofGeneral under
  2681 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2682 
  2683   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2684 
  2685 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2686 matching the current goal as introduction rule and not having "HOL."
  2687 in their name (i.e. not being defined in theory HOL).
  2688 
  2689 * Command 'thms_containing' has been discontinued in favour of
  2690 'find_theorems'; INCOMPATIBILITY.
  2691 
  2692 * Communication with Proof General is now 8bit clean, which means that
  2693 Unicode text in UTF-8 encoding may be used within theory texts (both
  2694 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2695 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2696 
  2697   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2698   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2699 
  2700 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2701 Classical Reasoner.  Typical big applications run around 2 times
  2702 faster.
  2703 
  2704 
  2705 *** Document preparation ***
  2706 
  2707 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2708 of raw sources.  Only those symbols that do not require additional
  2709 LaTeX packages (depending on comments in isabellesym.sty) are
  2710 displayed properly, everything else is left verbatim.  isatool display
  2711 and isatool print are used as front ends (these are subject to the
  2712 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2713 
  2714 * Command tags control specific markup of certain regions of text,
  2715 notably folding and hiding.  Predefined tags include "theory" (for
  2716 theory begin and end), "proof" for proof commands, and "ML" for
  2717 commands involving ML code; the additional tags "visible" and
  2718 "invisible" are unused by default.  Users may give explicit tag
  2719 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2720 interpretation of tags is determined by the LaTeX job during document
  2721 preparation: see option -V of isatool usedir, or options -n and -t of
  2722 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2723 \isadroptag.
  2724 
  2725 Several document versions may be produced at the same time via isatool
  2726 usedir (the generated index.html will link all of them).  Typical
  2727 specifications include ''-V document=theory,proof,ML'' to present
  2728 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2729 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2730 these parts without any formal replacement text.  The Isabelle site
  2731 default settings produce ''document'' and ''outline'' versions as
  2732 specified above.
  2733 
  2734 * Several new antiquotations:
  2735 
  2736   @{term_type term} prints a term with its type annotated;
  2737 
  2738   @{typeof term} prints the type of a term;
  2739 
  2740   @{const const} is the same as @{term const}, but checks that the
  2741   argument is a known logical constant;
  2742 
  2743   @{term_style style term} and @{thm_style style thm} print a term or
  2744   theorem applying a "style" to it
  2745 
  2746   @{ML text}
  2747 
  2748 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2749 definitions, equations, inequations etc., 'concl' printing only the
  2750 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2751 to print the specified premise.  TermStyle.add_style provides an ML
  2752 interface for introducing further styles.  See also the "LaTeX Sugar"
  2753 document practical applications.  The ML antiquotation prints
  2754 type-checked ML expressions verbatim.
  2755 
  2756 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2757 and 'text' support optional locale specification '(in loc)', which
  2758 specifies the default context for interpreting antiquotations.  For
  2759 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2760 
  2761 * Option 'locale=NAME' of antiquotations specifies an alternative
  2762 context interpreting the subsequent argument.  For example: @{thm
  2763 [locale=lattice] inf_assoc}.
  2764 
  2765 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2766 a proof context.
  2767 
  2768 * Proper output of antiquotations for theory commands involving a
  2769 proof context (such as 'locale' or 'theorem (in loc) ...').
  2770 
  2771 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2772 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2773 
  2774 * isatool usedir: new option -C (default true) controls whether option
  2775 -D should include a copy of the original document directory; -C false
  2776 prevents unwanted effects such as copying of administrative CVS data.
  2777 
  2778 
  2779 *** Pure ***
  2780 
  2781 * Considerably improved version of 'constdefs' command.  Now performs
  2782 automatic type-inference of declared constants; additional support for
  2783 local structure declarations (cf. locales and HOL records), see also
  2784 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2785 sequential dependencies of definitions within a single 'constdefs'
  2786 section; moreover, the declared name needs to be an identifier.  If
  2787 all fails, consider to fall back on 'consts' and 'defs' separately.
  2788 
  2789 * Improved indexed syntax and implicit structures.  First of all,
  2790 indexed syntax provides a notational device for subscripted
  2791 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2792 expressions.  Secondly, in a local context with structure
  2793 declarations, number indexes \<^sub>n or the empty index (default
  2794 number 1) refer to a certain fixed variable implicitly; option
  2795 show_structs controls printing of implicit structures.  Typical
  2796 applications of these concepts involve record types and locales.
  2797 
  2798 * New command 'no_syntax' removes grammar declarations (and
  2799 translations) resulting from the given syntax specification, which is
  2800 interpreted in the same manner as for the 'syntax' command.
  2801 
  2802 * 'Advanced' translation functions (parse_translation etc.) may depend
  2803 on the signature of the theory context being presently used for
  2804 parsing/printing, see also isar-ref manual.
  2805 
  2806 * Improved 'oracle' command provides a type-safe interface to turn an
  2807 ML expression of type theory -> T -> term into a primitive rule of
  2808 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2809 is already included here); see also FOL/ex/IffExample.thy;
  2810 INCOMPATIBILITY.
  2811 
  2812 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2813 before); "cI" is no longer bound, use "c.intro" instead.
  2814 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2815 axclasses vs. locales.
  2816 
  2817 * Improved internal renaming of symbolic identifiers -- attach primes
  2818 instead of base 26 numbers.
  2819 
  2820 * New flag show_question_marks controls printing of leading question
  2821 marks in schematic variable names.
  2822 
  2823 * In schematic variable names, *any* symbol following \<^isub> or
  2824 \<^isup> is now treated as part of the base name.  For example, the
  2825 following works without printing of awkward ".0" indexes:
  2826 
  2827   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2828     by simp
  2829 
  2830 * Inner syntax includes (*(*nested*) comments*).
  2831 
  2832 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2833 annotations as "(00...)".
  2834 
  2835 * Clear separation of logical types and nonterminals, where the latter
  2836 may only occur in 'syntax' specifications or type abbreviations.
  2837 Before that distinction was only partially implemented via type class
  2838 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2839 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2840 exotic syntax specifications may require further adaption
  2841 (e.g. Cube/Cube.thy).
  2842 
  2843 * Removed obsolete type class "logic", use the top sort {} instead.
  2844 Note that non-logical types should be declared as 'nonterminals'
  2845 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2846 specifications.
  2847 
  2848 * Attributes 'induct' and 'cases': type or set names may now be
  2849 locally fixed variables as well.
  2850 
  2851 * Simplifier: can now control the depth to which conditional rewriting
  2852 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2853 Limit.
  2854 
  2855 * Simplifier: simplification procedures may now take the current
  2856 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2857 interface), which is very useful for calling the Simplifier
  2858 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2859 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2860 low-level mk_simproc no longer applies Logic.varify internally, to
  2861 allow for use in a context of fixed variables.
  2862 
  2863 * thin_tac now works even if the assumption being deleted contains !!
  2864 or ==>.  More generally, erule now works even if the major premise of
  2865 the elimination rule contains !! or ==>.
  2866 
  2867 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2868 
  2869 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2870 from Pure, which contains all common declarations already.  Both
  2871 theories are defined via plain Isabelle/Isar .thy files.
  2872 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2873 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2874 use isatool fixcpure to adapt your theory and ML sources.
  2875 
  2876 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2877 selections of theorems in named facts via index ranges.
  2878 
  2879 * 'print_theorems': in theory mode, really print the difference
  2880 wrt. the last state (works for interactive theory development only),
  2881 in proof mode print all local facts (cf. 'print_facts');
  2882 
  2883 * 'hide': option '(open)' hides only base names.
  2884 
  2885 * More efficient treatment of intermediate checkpoints in interactive
  2886 theory development.
  2887 
  2888 * Code generator is now invoked via code_module (incremental code
  2889 generation) and code_library (modular code generation, ML structures
  2890 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2891 must be quoted when used as identifiers.
  2892 
  2893 * New 'value' command for reading, evaluating and printing terms using
  2894 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2895 quoted when used as identifier.
  2896 
  2897 
  2898 *** Locales ***
  2899 
  2900 * New commands for the interpretation of locale expressions in
  2901 theories (1), locales (2) and proof contexts (3).  These generate
  2902 proof obligations from the expression specification.  After the
  2903 obligations have been discharged, theorems of the expression are added
  2904 to the theory, target locale or proof context.  The synopsis of the
  2905 commands is a follows:
  2906 
  2907   (1) interpretation expr inst
  2908   (2) interpretation target < expr
  2909   (3) interpret expr inst
  2910 
  2911 Interpretation in theories and proof contexts require a parameter
  2912 instantiation of terms from the current context.  This is applied to
  2913 specifications and theorems of the interpreted expression.
  2914 Interpretation in locales only permits parameter renaming through the
  2915 locale expression.  Interpretation is smart in that interpretations
  2916 that are active already do not occur in proof obligations, neither are
  2917 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2918 inspect active interpretations of a particular locale.  For details,
  2919 see the Isar Reference manual.  Examples can be found in
  2920 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2921 
  2922 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2923 'interpret' instead.
  2924 
  2925 * New context element 'constrains' for adding type constraints to
  2926 parameters.
  2927 
  2928 * Context expressions: renaming of parameters with syntax
  2929 redeclaration.
  2930 
  2931 * Locale declaration: 'includes' disallowed.
  2932 
  2933 * Proper static binding of attribute syntax -- i.e. types / terms /
  2934 facts mentioned as arguments are always those of the locale definition
  2935 context, independently of the context of later invocations.  Moreover,
  2936 locale operations (renaming and type / term instantiation) are applied
  2937 to attribute arguments as expected.
  2938 
  2939 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2940 actual attributes; rare situations may require Attrib.attribute to
  2941 embed those attributes into Attrib.src that lack concrete syntax.
  2942 Attribute implementations need to cooperate properly with the static
  2943 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2944 Attrib.XXX_thm etc. already do the right thing without further
  2945 intervention.  Only unusual applications -- such as "where" or "of"
  2946 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2947 on the context and the facts involved -- may have to assign parsed
  2948 values to argument tokens explicitly.
  2949 
  2950 * Changed parameter management in theorem generation for long goal
  2951 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2952 theorem statement in rare situations.
  2953 
  2954 * Locale inspection command 'print_locale' omits notes elements.  Use
  2955 'print_locale!' to have them included in the output.
  2956 
  2957 
  2958 *** Provers ***
  2959 
  2960 * Provers/hypsubst.ML: improved version of the subst method, for
  2961 single-step rewriting: it now works in bound variable contexts. New is
  2962 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2963 rewrite a different subterm than the original subst method, which is
  2964 still available as 'simplesubst'.
  2965 
  2966 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2967 and quasi orders.
  2968 
  2969 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2970 reflexive-transitive closure of relations.
  2971 
  2972 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2973 limit (previously hard-coded with a value of 20) user-definable.
  2974 
  2975 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2976 is peformed already.  Object-logics merely need to finish their
  2977 initial simpset configuration as before.  INCOMPATIBILITY.
  2978 
  2979 
  2980 *** HOL ***
  2981 
  2982 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2983 
  2984   syntax (epsilon)
  2985     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2986 
  2987 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2988 and x-symbol; use option '-m epsilon' to get it actually printed.
  2989 Moreover, the mathematically important symbolic identifier \<epsilon>
  2990 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2991 
  2992 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2993 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2994 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2995 support corresponding Isar calculations.
  2996 
  2997 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2998 instead of ":".
  2999 
  3000 * theory SetInterval: changed the syntax for open intervals:
  3001 
  3002   Old       New
  3003   {..n(}    {..<n}
  3004   {)n..}    {n<..}
  3005   {m..n(}   {m..<n}
  3006   {)m..n}   {m<..n}
  3007   {)m..n(}  {m<..<n}
  3008 
  3009 The old syntax is still supported but will disappear in the next
  3010 release.  For conversion use the following Emacs search and replace
  3011 patterns (these are not perfect but work quite well):
  3012 
  3013   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3014   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3015 
  3016 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3017 equalities in commutative rings; method 'algebra' provides a generic
  3018 interface.
  3019 
  3020 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3021 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3022 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3023 be a tuple pattern.
  3024 
  3025 Some new syntax forms are available:
  3026 
  3027   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3028   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3029   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3030   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3031 
  3032 The latter form "\<Sum>x < k. e" used to be based on a separate
  3033 function "Summation", which has been discontinued.
  3034 
  3035 * theory Finite_Set: in structured induction proofs, the insert case
  3036 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3037 (insert F x)'.
  3038 
  3039 * The 'refute' command has been extended to support a much larger
  3040 fragment of HOL, including axiomatic type classes, constdefs and
  3041 typedefs, inductive datatypes and recursion.
  3042 
  3043 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3044 Requires zChaff with proof generation to be installed.  See
  3045 HOL/ex/SAT_Examples.thy for examples.
  3046 
  3047 * Datatype induction via method 'induct' now preserves the name of the
  3048 induction variable. For example, when proving P(xs::'a list) by
  3049 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3050 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3051 in unstructured proof scripts.
  3052 
  3053 * Reworked implementation of records.  Improved scalability for
  3054 records with many fields, avoiding performance problems for type
  3055 inference. Records are no longer composed of nested field types, but
  3056 of nested extension types. Therefore the record type only grows linear
  3057 in the number of extensions and not in the number of fields.  The
  3058 top-level (users) view on records is preserved.  Potential
  3059 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3060 old record representation. The type generated for a record is called
  3061 <record_name>_ext_type.
  3062 
  3063 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3064 proofs triggered by a record definition or a simproc (if
  3065 quick_and_dirty is enabled).  Definitions of large records can take
  3066 quite long.
  3067 
  3068 New simproc record_upd_simproc for simplification of multiple record
  3069 updates enabled by default.  Moreover, trivial updates are also
  3070 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3071 occasionally, since simplification is more powerful by default.
  3072 
  3073 * typedef: proper support for polymorphic sets, which contain extra
  3074 type-variables in the term.
  3075 
  3076 * Simplifier: automatically reasons about transitivity chains
  3077 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3078 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3079 old proofs break occasionally as simplification may now solve more
  3080 goals than previously.
  3081 
  3082 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3083 present.  Works for all partial orders (class "order"), in particular
  3084 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3085 just like y <= x.
  3086 
  3087 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3088 bound variable or a constant then the let is unfolded.  Otherwise
  3089 first a is simplified to b, and then f b is simplified to g. If
  3090 possible we abstract b from g arriving at "let x = b in h x",
  3091 otherwise we unfold the let and arrive at g.  The simproc can be
  3092 enabled/disabled by the reference use_let_simproc.  Potential
  3093 INCOMPATIBILITY since simplification is more powerful by default.
  3094 
  3095 * Classical reasoning: the meson method now accepts theorems as arguments.
  3096 
  3097 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3098 jobs to provide advice on the provability of subgoals.
  3099 
  3100 * Theory OrderedGroup and Ring_and_Field: various additions and
  3101 improvements to faciliate calculations involving equalities and
  3102 inequalities.
  3103 
  3104 The following theorems have been eliminated or modified
  3105 (INCOMPATIBILITY):
  3106 
  3107   abs_eq             now named abs_of_nonneg
  3108   abs_of_ge_0        now named abs_of_nonneg
  3109   abs_minus_eq       now named abs_of_nonpos
  3110   imp_abs_id         now named abs_of_nonneg
  3111   imp_abs_neg_id     now named abs_of_nonpos
  3112   mult_pos           now named mult_pos_pos
  3113   mult_pos_le        now named mult_nonneg_nonneg
  3114   mult_pos_neg_le    now named mult_nonneg_nonpos
  3115   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3116   mult_neg           now named mult_neg_neg
  3117   mult_neg_le        now named mult_nonpos_nonpos
  3118 
  3119 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3120      
  3121      zero_le_square
  3122      not_square_less_zero 
  3123 
  3124   The following lemmas have been deleted from Real/RealPow:
  3125   
  3126      realpow_zero_zero
  3127      realpow_two
  3128      realpow_less
  3129      zero_le_power
  3130      realpow_two_le
  3131      abs_realpow_two
  3132      realpow_two_abs     
  3133 
  3134 * Theory Parity: added rules for simplifying exponents.
  3135 
  3136 * Theory List:
  3137 
  3138 The following theorems have been eliminated or modified
  3139 (INCOMPATIBILITY):
  3140 
  3141   list_all_Nil       now named list_all.simps(1)
  3142   list_all_Cons      now named list_all.simps(2)
  3143   list_all_conv      now named list_all_iff
  3144   set_mem_eq         now named mem_iff
  3145 
  3146 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3147 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3148 
  3149 
  3150 *** HOL-Complex ***
  3151 
  3152 * Theory RealDef: better support for embedding natural numbers and
  3153 integers in the reals.
  3154 
  3155 The following theorems have been eliminated or modified
  3156 (INCOMPATIBILITY):
  3157 
  3158   exp_ge_add_one_self  now requires no hypotheses
  3159   real_of_int_add      reversed direction of equality (use [symmetric])
  3160   real_of_int_minus    reversed direction of equality (use [symmetric])
  3161   real_of_int_diff     reversed direction of equality (use [symmetric])
  3162   real_of_int_mult     reversed direction of equality (use [symmetric])
  3163 
  3164 * Theory RComplete: expanded support for floor and ceiling functions.
  3165 
  3166 * Theory Ln is new, with properties of the natural logarithm
  3167 
  3168 * Hyperreal: There is a new type constructor "star" for making
  3169 nonstandard types.  The old type names are now type synonyms:
  3170 
  3171   hypreal = real star
  3172   hypnat = nat star
  3173   hcomplex = complex star
  3174 
  3175 * Hyperreal: Many groups of similarly-defined constants have been
  3176 replaced by polymorphic versions (INCOMPATIBILITY):
  3177 
  3178   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3179 
  3180   starset      <-- starsetNat, starsetC
  3181   *s*          <-- *sNat*, *sc*
  3182   starset_n    <-- starsetNat_n, starsetC_n
  3183   *sn*         <-- *sNatn*, *scn*
  3184   InternalSets <-- InternalNatSets, InternalCSets
  3185 
  3186   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3187   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3188   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3189   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3190   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3191 
  3192 * Hyperreal: Many type-specific theorems have been removed in favor of
  3193 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3194 
  3195   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3196   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3197   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3198   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3199   right_minus <-- hypreal_add_minus
  3200   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3201   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3202   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3203   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3204   mult_1_right <-- hcomplex_mult_one_right
  3205   mult_zero_left <-- hcomplex_mult_zero_left
  3206   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3207   right_distrib <-- hypnat_add_mult_distrib2
  3208   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3209   right_inverse <-- hypreal_mult_inverse
  3210   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3211   order_refl <-- {hypreal,hypnat}_le_refl
  3212   order_trans <-- {hypreal,hypnat}_le_trans
  3213   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3214   order_less_le <-- {hypreal,hypnat}_less_le
  3215   linorder_linear <-- {hypreal,hypnat}_le_linear
  3216   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3217   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3218   add_nonneg_nonneg <-- hypreal_le_add_order
  3219 
  3220 * Hyperreal: Separate theorems having to do with type-specific
  3221 versions of constants have been merged into theorems that apply to the
  3222 new polymorphic constants (INCOMPATIBILITY):
  3223 
  3224   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3225   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3226   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3227   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3228   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3229   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3230   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3231   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3232   STAR_diff <-- {STAR,STARC}_diff
  3233   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3234     STARC_hcomplex_of_complex}_image_subset
  3235   starset_n_Un <-- starset{Nat,C}_n_Un
  3236   starset_n_Int <-- starset{Nat,C}_n_Int
  3237   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3238   starset_n_diff <-- starset{Nat,C}_n_diff
  3239   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3240   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3241   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3242   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3243   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3244   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3245   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3246   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3247   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3248   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3249   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3250   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3251   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3252   starfun_diff <-- starfun{C,RC,CR}_diff
  3253   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3254   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3255   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3256   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3257   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3258   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3259   starfun_Id <-- starfunC_Id
  3260   starfun_approx <-- starfun{Nat,CR}_approx
  3261   starfun_capprox <-- starfun{C,RC}_capprox
  3262   starfun_abs <-- starfunNat_rabs
  3263   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3264   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3265   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3266   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3267   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3268   starfun_add_approx <-- starfunCR_add_approx
  3269   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3270   starfun_divide <-- starfun{C,CR,RC}_divide
  3271   starfun_n <-- starfun{Nat,C}_n
  3272   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3273   starfun_n_add <-- starfun{Nat,C}_n_add
  3274   starfun_n_add_minus <-- starfunNat_n_add_minus
  3275   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3276   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3277   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3278 
  3279   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3280   star_n_minus <-- {hypreal,hcomplex}_minus
  3281   star_n_diff <-- {hypreal,hcomplex}_diff
  3282   star_n_mult <-- {hypreal,hcomplex}_mult
  3283   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3284   star_n_le <-- {hypreal,hypnat}_le
  3285   star_n_less <-- {hypreal,hypnat}_less
  3286   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3287   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3288   star_n_abs <-- hypreal_hrabs
  3289   star_n_divide <-- hcomplex_divide
  3290 
  3291   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3292   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3293   star_of_diff <-- hypreal_of_real_diff
  3294   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3295   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3296   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3297   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3298   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3299   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3300   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3301   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3302   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3303   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3304   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3305   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3306   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3307   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3308   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3309   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3310   star_of_power <-- hypreal_of_real_power
  3311   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3312 
  3313 * Hyperreal: new method "transfer" that implements the transfer
  3314 principle of nonstandard analysis. With a subgoal that mentions
  3315 nonstandard types like "'a star", the command "apply transfer"
  3316 replaces it with an equivalent one that mentions only standard types.
  3317 To be successful, all free variables must have standard types; non-
  3318 standard variables must have explicit universal quantifiers.
  3319 
  3320 * Hyperreal: A theory of Taylor series.
  3321 
  3322 
  3323 *** HOLCF ***
  3324 
  3325 * Discontinued special version of 'constdefs' (which used to support
  3326 continuous functions) in favor of the general Pure one with full
  3327 type-inference.
  3328 
  3329 * New simplification procedure for solving continuity conditions; it
  3330 is much faster on terms with many nested lambda abstractions (cubic
  3331 instead of exponential time).
  3332 
  3333 * New syntax for domain package: selector names are now optional.
  3334 Parentheses should be omitted unless argument is lazy, for example:
  3335 
  3336   domain 'a stream = cons "'a" (lazy "'a stream")
  3337 
  3338 * New command 'fixrec' for defining recursive functions with pattern
  3339 matching; defining multiple functions with mutual recursion is also
  3340 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3341 sinr, or any data constructor defined by the domain package. The given
  3342 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3343 syntax and examples.
  3344 
  3345 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3346 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3347 but the proof obligation additionally includes an admissibility
  3348 requirement. The packages generate instances of class cpo or pcpo,
  3349 with continuity and strictness theorems for Rep and Abs.
  3350 
  3351 * HOLCF: Many theorems have been renamed according to a more standard naming
  3352 scheme (INCOMPATIBILITY):
  3353 
  3354   foo_inject:  "foo$x = foo$y ==> x = y"
  3355   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3356   foo_less:    "(foo$x << foo$y) = (x << y)"
  3357   foo_strict:  "foo$UU = UU"
  3358   foo_defined: "... ==> foo$x ~= UU"
  3359   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3360 
  3361 
  3362 *** ZF ***
  3363 
  3364 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3365 including the First Isomorphism Theorem (on quotienting by the kernel
  3366 of a homomorphism).
  3367 
  3368 * ZF/Simplifier: install second copy of type solver that actually
  3369 makes use of TC rules declared to Isar proof contexts (or locales);
  3370 the old version is still required for ML proof scripts.
  3371 
  3372 
  3373 *** Cube ***
  3374 
  3375 * Converted to Isar theory format; use locales instead of axiomatic
  3376 theories.
  3377 
  3378 
  3379 *** ML ***
  3380 
  3381 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3382 for ||>, ||>>, |>>,
  3383 
  3384 * Pure/library.ML no longer defines its own option datatype, but uses
  3385 that of the SML basis, which has constructors NONE and SOME instead of
  3386 None and Some, as well as exception Option.Option instead of OPTION.
  3387 The functions the, if_none, is_some, is_none have been adapted
  3388 accordingly, while Option.map replaces apsome.
  3389 
  3390 * Pure/library.ML: the exception LIST has been given up in favour of
  3391 the standard exceptions Empty and Subscript, as well as
  3392 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3393 superceded by the standard hd and tl functions etc.
  3394 
  3395 A number of basic list functions are no longer exported to the ML
  3396 toplevel, as they are variants of predefined functions.  The following
  3397 suggests how one can translate existing code:
  3398 
  3399     rev_append xs ys = List.revAppend (xs, ys)
  3400     nth_elem (i, xs) = List.nth (xs, i)
  3401     last_elem xs = List.last xs
  3402     flat xss = List.concat xss
  3403     seq fs = List.app fs
  3404     partition P xs = List.partition P xs
  3405     mapfilter f xs = List.mapPartial f xs
  3406 
  3407 * Pure/library.ML: several combinators for linear functional
  3408 transformations, notably reverse application and composition:
  3409 
  3410   x |> f                f #> g
  3411   (x, y) |-> f          f #-> g
  3412 
  3413 * Pure/library.ML: introduced/changed precedence of infix operators:
  3414 
  3415   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3416   infix 2 ?;
  3417   infix 3 o oo ooo oooo;
  3418   infix 4 ~~ upto downto;
  3419 
  3420 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3421 infix operators.
  3422 
  3423 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3424 fold_map support linear functional transformations and nesting.  For
  3425 example:
  3426 
  3427   fold f [x1, ..., xN] y =
  3428     y |> f x1 |> ... |> f xN
  3429 
  3430   (fold o fold) f [xs1, ..., xsN] y =
  3431     y |> fold f xs1 |> ... |> fold f xsN
  3432 
  3433   fold f [x1, ..., xN] =
  3434     f x1 #> ... #> f xN
  3435 
  3436   (fold o fold) f [xs1, ..., xsN] =
  3437     fold f xs1 #> ... #> fold f xsN
  3438 
  3439 * Pure/library.ML: the following selectors on type 'a option are
  3440 available:
  3441 
  3442   the:               'a option -> 'a  (*partial*)
  3443   these:             'a option -> 'a  where 'a = 'b list
  3444   the_default: 'a -> 'a option -> 'a
  3445   the_list:          'a option -> 'a list
  3446 
  3447 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3448 basic operations for association lists, following natural argument
  3449 order; moreover the explicit equality predicate passed here avoids
  3450 potentially expensive polymorphic runtime equality checks.
  3451 The old functions may be expressed as follows:
  3452 
  3453   assoc = uncurry (AList.lookup (op =))
  3454   assocs = these oo AList.lookup (op =)
  3455   overwrite = uncurry (AList.update (op =)) o swap
  3456 
  3457 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3458 
  3459   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3460   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3461 
  3462 replacing make_keylist and keyfilter (occassionally used)
  3463 Naive rewrites:
  3464 
  3465   make_keylist = AList.make
  3466   keyfilter = AList.find (op =)
  3467 
  3468 * eq_fst and eq_snd now take explicit equality parameter, thus
  3469   avoiding eqtypes. Naive rewrites:
  3470 
  3471     eq_fst = eq_fst (op =)
  3472     eq_snd = eq_snd (op =)
  3473 
  3474 * Removed deprecated apl and apr (rarely used).
  3475   Naive rewrites:
  3476 
  3477     apl (n, op) =>>= curry op n
  3478     apr (op, m) =>>= fn n => op (n, m)
  3479 
  3480 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3481 provides a reasonably efficient light-weight implementation of sets as
  3482 lists.
  3483 
  3484 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3485 few new operations; existing lookup and update are now curried to
  3486 follow natural argument order (for use with fold etc.);
  3487 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3488 
  3489 * Pure/General: output via the Isabelle channels of
  3490 writeln/warning/error etc. is now passed through Output.output, with a
  3491 hook for arbitrary transformations depending on the print_mode
  3492 (cf. Output.add_mode -- the first active mode that provides a output
  3493 function wins).  Already formatted output may be embedded into further
  3494 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3495 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3496 accommodate easy composition of diagnostic messages etc.  Programmers
  3497 rarely need to care about Output.output or Output.raw at all, with
  3498 some notable exceptions: Output.output is required when bypassing the
  3499 standard channels (writeln etc.), or in token translations to produce
  3500 properly formatted results; Output.raw is required when capturing
  3501 already output material that will eventually be presented to the user
  3502 a second time.  For the default print mode, both Output.output and
  3503 Output.raw have no effect.
  3504 
  3505 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3506 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3507 cumulative results are displayed at the end of a batch session.
  3508 
  3509 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3510 replaced by File.platform_path and File.shell_path (with appropriate
  3511 hooks).  This provides a clean interface for unusual systems where the
  3512 internal and external process view of file names are different.
  3513 
  3514 * Pure: more efficient orders for basic syntactic entities: added
  3515 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3516 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3517 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3518 orders now -- potential INCOMPATIBILITY for code that depends on a
  3519 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3520 Library.sort_strings on result).
  3521 
  3522 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3523 fold_types traverse types/terms from left to right, observing natural
  3524 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3525 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3526 
  3527 * Pure: name spaces have been refined, with significant changes of the
  3528 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3529 to extern(_table).  The plain name entry path is superceded by a
  3530 general 'naming' context, which also includes the 'policy' to produce
  3531 a fully qualified name and external accesses of a fully qualified
  3532 name; NameSpace.extend is superceded by context dependent
  3533 Sign.declare_name.  Several theory and proof context operations modify
  3534 the naming context.  Especially note Theory.restore_naming and
  3535 ProofContext.restore_naming to get back to a sane state; note that
  3536 Theory.add_path is no longer sufficient to recover from
  3537 Theory.absolute_path in particular.
  3538 
  3539 * Pure: new flags short_names (default false) and unique_names
  3540 (default true) for controlling output of qualified names.  If
  3541 short_names is set, names are printed unqualified.  If unique_names is
  3542 reset, the name prefix is reduced to the minimum required to achieve
  3543 the original result when interning again, even if there is an overlap
  3544 with earlier declarations.
  3545 
  3546 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3547 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3548 (useful for printing error messages).  INCOMPATIBILITY.
  3549 
  3550 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3551 Theory.theory are now identified, referring to the universal
  3552 Context.theory (see Pure/context.ML).  Actual signature and theory
  3553 content is managed as theory data.  The old code and interfaces were
  3554 spread over many files and structures; the new arrangement introduces
  3555 considerable INCOMPATIBILITY to gain more clarity:
  3556 
  3557   Context -- theory management operations (name, identity, inclusion,
  3558     parents, ancestors, merge, etc.), plus generic theory data;
  3559 
  3560   Sign -- logical signature and syntax operations (declaring consts,
  3561     types, etc.), plus certify/read for common entities;
  3562 
  3563   Theory -- logical theory operations (stating axioms, definitions,
  3564     oracles), plus a copy of logical signature operations (consts,
  3565     types, etc.); also a few basic management operations (Theory.copy,
  3566     Theory.merge, etc.)
  3567 
  3568 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3569 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3570 for convenience -- they merely return the theory.
  3571 
  3572 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3573 
  3574 * Pure: the Isar proof context type is already defined early in Pure
  3575 as Context.proof (note that ProofContext.context and Proof.context are
  3576 aliases, where the latter is the preferred name).  This enables other
  3577 Isabelle components to refer to that type even before Isar is present.
  3578 
  3579 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3580 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3581 any of these kinds.  For example, Sign.intern typeK is now
  3582 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3583 Theory.hide_types.  Also note that former
  3584 Theory.hide_classes/types/consts are now
  3585 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3586 internalize their arguments!  INCOMPATIBILITY.
  3587 
  3588 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3589 datatype thmref (with constructors Name and NameSelection) instead of
  3590 plain string -- INCOMPATIBILITY;
  3591 
  3592 * Pure: cases produced by proof methods specify options, where NONE
  3593 means to remove case bindings -- INCOMPATIBILITY in
  3594 (RAW_)METHOD_CASES.
  3595 
  3596 * Pure: the following operations retrieve axioms or theorems from a
  3597 theory node or theory hierarchy, respectively:
  3598 
  3599   Theory.axioms_of: theory -> (string * term) list
  3600   Theory.all_axioms_of: theory -> (string * term) list
  3601   PureThy.thms_of: theory -> (string * thm) list
  3602   PureThy.all_thms_of: theory -> (string * thm) list
  3603 
  3604 * Pure: print_tac now outputs the goal through the trace channel.
  3605 
  3606 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3607 Reference Toplevel.debug (default false) controls detailed printing
  3608 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3609 controls execution profiling -- set to 1 for time and 2 for space
  3610 (both increase the runtime).
  3611 
  3612 * Isar session: The initial use of ROOT.ML is now always timed,
  3613 i.e. the log will show the actual process times, in contrast to the
  3614 elapsed wall-clock time that the outer shell wrapper produces.
  3615 
  3616 * Simplifier: improved handling of bound variables (nameless
  3617 representation, avoid allocating new strings).  Simprocs that invoke
  3618 the Simplifier recursively should use Simplifier.inherit_bounds to
  3619 avoid local name clashes.  Failure to do so produces warnings
  3620 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3621 for further details.
  3622 
  3623 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3624 bindings for all theorems stored within a given theory; this may help
  3625 in porting non-Isar theories to Isar ones, while keeping ML proof
  3626 scripts for the time being.
  3627 
  3628 * ML operator HTML.with_charset specifies the charset begin used for
  3629 generated HTML files.  For example:
  3630 
  3631   HTML.with_charset "utf-8" use_thy "Hebrew";
  3632   HTML.with_charset "utf-8" use_thy "Chinese";
  3633 
  3634 
  3635 *** System ***
  3636 
  3637 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3638 isabelle, isatool etc.).
  3639 
  3640 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3641 isatool doc, isatool mkdir, display_drafts etc.).
  3642 
  3643 * isatool usedir: option -f allows specification of the ML file to be
  3644 used by Isabelle; default is ROOT.ML.
  3645 
  3646 * New isatool version outputs the version identifier of the Isabelle
  3647 distribution being used.
  3648 
  3649 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3650 (containing Boolean satisfiability problems) into Isabelle/HOL
  3651 theories.
  3652 
  3653 
  3654 
  3655 New in Isabelle2004 (April 2004)
  3656 --------------------------------
  3657 
  3658 *** General ***
  3659 
  3660 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3661   Replaces linorder.ML.
  3662 
  3663 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3664   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3665   (\<a>...\<z>), are now considered normal letters, and can therefore
  3666   be used anywhere where an ASCII letter (a...zA...Z) has until
  3667   now. COMPATIBILITY: This obviously changes the parsing of some
  3668   terms, especially where a symbol has been used as a binder, say
  3669   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3670   as an identifier.  Fix it by inserting a space around former
  3671   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3672   existing theory and ML files.
  3673 
  3674 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3675 
  3676 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3677   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3678   a normal (but invisible) letter. For multiple letter subscripts repeat
  3679   \<^isub> like this: x\<^isub>1\<^isub>2.
  3680 
  3681 * Pure: There are now sub-/superscripts that can span more than one
  3682   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3683   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3684   superscript. The new control characters are not identifier parts.
  3685 
  3686 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3687   content of "..." to the latex file instead of \isacntrl... . The "..."
  3688   may consist of any printable characters excluding the end bracket >.
  3689 
  3690 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3691   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3692   declare constants "final", which prevents their being given a definition
  3693   later.  It is useful for constants whose behaviour is fixed axiomatically
  3694   rather than definitionally, such as the meta-logic connectives.
  3695 
  3696 * Pure: 'instance' now handles general arities with general sorts
  3697   (i.e. intersections of classes),
  3698 
  3699 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3700   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3701   It can be changed to alter the colors/layout of generated pages.
  3702 
  3703 
  3704 *** Isar ***
  3705 
  3706 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3707   cut_tac, subgoal_tac and thin_tac:
  3708   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3709     locales are no longer forced to write Isar proof scripts.
  3710     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3711     emulations.
  3712   - INCOMPATIBILITY: names of variables to be instantiated may no
  3713     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3714     This is consistent with the instantiation attribute "where".
  3715 
  3716 * Attributes "where" and "of":
  3717   - Now take type variables of instantiated theorem into account when reading
  3718     the instantiation string.  This fixes a bug that caused instantiated
  3719     theorems to have too special types in some circumstances.
  3720   - "where" permits explicit instantiations of type variables.
  3721 
  3722 * Calculation commands "moreover" and "also" no longer interfere with
  3723   current facts ("this"), admitting arbitrary combinations with "then"
  3724   and derived forms.
  3725 
  3726 * Locales:
  3727   - Goal statements involving the context element "includes" no longer
  3728     generate theorems with internal delta predicates (those ending on
  3729     "_axioms") in the premise.
  3730     Resolve particular premise with <locale>.intro to obtain old form.
  3731   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3732     specification and "includes" elements in goal statement.
  3733   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3734     [intro?] and [elim?] (respectively) by default.
  3735   - Experimental command for instantiation of locales in proof contexts:
  3736         instantiate <label>[<attrs>]: <loc>
  3737     Instantiates locale <loc> and adds all its theorems to the current context
  3738     taking into account their attributes.  Label and attrs are optional
  3739     modifiers, like in theorem declarations.  If present, names of
  3740     instantiated theorems are qualified with <label>, and the attributes
  3741     <attrs> are applied after any attributes these theorems might have already.
  3742       If the locale has assumptions, a chained fact of the form
  3743     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3744     are derived.  The command does not support old-style locales declared
  3745     with "locale (open)".
  3746       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3747 
  3748 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3749   (Isar) contexts.
  3750 
  3751 
  3752 *** HOL ***
  3753 
  3754 * Proof import: new image HOL4 contains the imported library from
  3755   the HOL4 system with about 2500 theorems. It is imported by
  3756   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3757   can be used like any other Isabelle image.  See
  3758   HOL/Import/HOL/README for more information.
  3759 
  3760 * Simplifier:
  3761   - Much improved handling of linear and partial orders.
  3762     Reasoners for linear and partial orders are set up for type classes
  3763     "linorder" and "order" respectively, and are added to the default simpset
  3764     as solvers.  This means that the simplifier can build transitivity chains
  3765     to solve goals from the assumptions.
  3766   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3767     of blast or auto after simplification become unnecessary because the goal
  3768     is solved by simplification already.
  3769 
  3770 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3771     all proved in axiomatic type classes for semirings, rings and fields.
  3772 
  3773 * Numerics:
  3774   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3775     now formalized using the Ring_and_Field theory mentioned above.
  3776   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3777     than before, because now they are set up once in a generic manner.
  3778   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3779     Look for the general versions in Ring_and_Field (and Power if they concern
  3780     exponentiation).
  3781 
  3782 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3783 
  3784 * Records:
  3785   - Record types are now by default printed with their type abbreviation
  3786     instead of the list of all field types. This can be configured via
  3787     the reference "print_record_type_abbr".
  3788   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3789     (not enabled by default).
  3790   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3791     EX x. x = sel r to True (not enabled by default).
  3792   - Tactic "record_split_simp_tac" to split and simplify records added.
  3793 
  3794 * 'specification' command added, allowing for definition by
  3795   specification.  There is also an 'ax_specification' command that
  3796   introduces the new constants axiomatically.
  3797 
  3798 * arith(_tac) is now able to generate counterexamples for reals as well.
  3799 
  3800 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3801 
  3802 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3803   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3804 
  3805 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3806   matrix theory to linear programming.
  3807 
  3808 * Unions and Intersections:
  3809   The latex output syntax of UN and INT has been changed
  3810   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3811   i.e. the index formulae has become a subscript.
  3812   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3813 
  3814 * Unions and Intersections over Intervals:
  3815   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3816   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3817   like in normal math, and corresponding versions for < and for intersection.
  3818 
  3819 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3820   lexicographic dictonary ordering has been added as "lexord".
  3821 
  3822 * ML: the legacy theory structures Int and List have been removed. They had
  3823   conflicted with ML Basis Library structures having the same names.
  3824 
  3825 * 'refute' command added to search for (finite) countermodels.  Only works
  3826   for a fragment of HOL.  The installation of an external SAT solver is
  3827   highly recommended.  See "HOL/Refute.thy" for details.
  3828 
  3829 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3830   formulae under an assignment of free variables to random values.
  3831   In contrast to 'refute', it can deal with inductive datatypes,
  3832   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3833   for examples.
  3834 
  3835 
  3836 *** HOLCF ***
  3837 
  3838 * Streams now come with concatenation and are part of the HOLCF image
  3839 
  3840 
  3841 
  3842 New in Isabelle2003 (May 2003)
  3843 ------------------------------
  3844 
  3845 *** General ***
  3846 
  3847 * Provers/simplifier:
  3848 
  3849   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3850     Assumptions are now subject to complete mutual simplification,
  3851     not just from left to right. The simplifier now preserves
  3852     the order of assumptions.
  3853 
  3854     Potential INCOMPATIBILITY:
  3855 
  3856     -- simp sometimes diverges where the old version did
  3857        not, e.g. invoking simp on the goal
  3858 
  3859         [| P (f x); y = x; f x = f y |] ==> Q
  3860 
  3861        now gives rise to the infinite reduction sequence
  3862 
  3863         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3864 
  3865        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3866        kind of problem.
  3867 
  3868     -- Tactics combining classical reasoner and simplification (such as auto)
  3869        are also affected by this change, because many of them rely on
  3870        simp. They may sometimes diverge as well or yield a different numbers
  3871        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3872        in case of problems. Sometimes subsequent calls to the classical
  3873        reasoner will fail because a preceeding call to the simplifier too
  3874        eagerly simplified the goal, e.g. deleted redundant premises.
  3875 
  3876   - The simplifier trace now shows the names of the applied rewrite rules
  3877 
  3878   - You can limit the number of recursive invocations of the simplifier
  3879     during conditional rewriting (where the simplifie tries to solve the
  3880     conditions before applying the rewrite rule):
  3881     ML "simp_depth_limit := n"
  3882     where n is an integer. Thus you can force termination where previously
  3883     the simplifier would diverge.
  3884 
  3885   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3886 
  3887   - No longer aborts on failed congruence proof.  Instead, the
  3888     congruence is ignored.
  3889 
  3890 * Pure: New generic framework for extracting programs from constructive
  3891   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3892   as HOL/Extraction for some case studies.
  3893 
  3894 * Pure: The main goal of the proof state is no longer shown by default, only
  3895 the subgoals. This behaviour is controlled by a new flag.
  3896    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3897 (ML: Proof.show_main_goal).
  3898 
  3899 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3900 rules whose conclusion matches subgoal 1:
  3901       PG menu: Isabelle/Isar -> Show me -> matching rules
  3902 The rules are ordered by how closely they match the subgoal.
  3903 In particular, rules that solve a subgoal outright are displayed first
  3904 (or rather last, the way they are printed).
  3905 (ML: ProofGeneral.print_intros())
  3906 
  3907 * Pure: New flag trace_unify_fail causes unification to print
  3908 diagnostic information (PG: in trace buffer) when it fails. This is
  3909 useful for figuring out why single step proofs like rule, erule or
  3910 assumption failed.
  3911 
  3912 * Pure: Locale specifications now produce predicate definitions
  3913 according to the body of text (covering assumptions modulo local
  3914 definitions); predicate "loc_axioms" covers newly introduced text,
  3915 while "loc" is cumulative wrt. all included locale expressions; the
  3916 latter view is presented only on export into the global theory
  3917 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3918 on the old view without predicates;
  3919 
  3920 * Pure: predefined locales "var" and "struct" are useful for sharing
  3921 parameters (as in CASL, for example); just specify something like
  3922 ``var x + var y + struct M'' as import;
  3923 
  3924 * Pure: improved thms_containing: proper indexing of facts instead of
  3925 raw theorems; check validity of results wrt. current name space;
  3926 include local facts of proof configuration (also covers active
  3927 locales), cover fixed variables in index; may use "_" in term
  3928 specification; an optional limit for the number of printed facts may
  3929 be given (the default is 40);
  3930 
  3931 * Pure: disallow duplicate fact bindings within new-style theory files
  3932 (batch-mode only);
  3933 
  3934 * Provers: improved induct method: assumptions introduced by case
  3935 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3936 the goal statement); "foo" still refers to all facts collectively;
  3937 
  3938 * Provers: the function blast.overloaded has been removed: all constants
  3939 are regarded as potentially overloaded, which improves robustness in exchange
  3940 for slight decrease in efficiency;
  3941 
  3942 * Provers/linorder: New generic prover for transitivity reasoning over
  3943 linear orders.  Note: this prover is not efficient!
  3944 
  3945 * Isar: preview of problems to finish 'show' now produce an error
  3946 rather than just a warning (in interactive mode);
  3947 
  3948 
  3949 *** HOL ***
  3950 
  3951 * arith(_tac)
  3952 
  3953  - Produces a counter example if it cannot prove a goal.
  3954    Note that the counter example may be spurious if the goal is not a formula
  3955    of quantifier-free linear arithmetic.
  3956    In ProofGeneral the counter example appears in the trace buffer.
  3957 
  3958  - Knows about div k and mod k where k is a numeral of type nat or int.
  3959 
  3960  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3961    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3962    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3963 
  3964 * simp's arithmetic capabilities have been enhanced a bit: it now
  3965 takes ~= in premises into account (by performing a case split);
  3966 
  3967 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3968 are distributed over a sum of terms;
  3969 
  3970 * New tactic "trans_tac" and method "trans" instantiate
  3971 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3972 "<=", "<" and "=").
  3973 
  3974 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3975 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3976 
  3977 * 'typedef' command has new option "open" to suppress the set
  3978 definition;
  3979 
  3980 * functions Min and Max on finite sets have been introduced (theory
  3981 Finite_Set);
  3982 
  3983 * attribute [symmetric] now works for relations as well; it turns
  3984 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3985 
  3986 * induct over a !!-quantified statement (say !!x1..xn):
  3987   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3988 
  3989 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3990 %x. None. Warning: empty_def now refers to the previously hidden definition
  3991 of the empty set.
  3992 
  3993 * Algebra: formalization of classical algebra.  Intended as base for
  3994 any algebraic development in Isabelle.  Currently covers group theory
  3995 (up to Sylow's theorem) and ring theory (Universal Property of
  3996 Univariate Polynomials).  Contributions welcome;
  3997 
  3998 * GroupTheory: deleted, since its material has been moved to Algebra;
  3999 
  4000 * Complex: new directory of the complex numbers with numeric constants,
  4001 nonstandard complex numbers, and some complex analysis, standard and
  4002 nonstandard (Jacques Fleuriot);
  4003 
  4004 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4005 
  4006 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4007 Fleuriot);
  4008 
  4009 * Real/HahnBanach: updated and adapted to locales;
  4010 
  4011 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4012 Gray and Kramer);
  4013 
  4014 * UNITY: added the Meier-Sanders theory of progress sets;
  4015 
  4016 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4017 as abstract algorithms, instantiated to the JVM;
  4018 
  4019 * Bali: Java source language formalization. Type system, operational
  4020 semantics, axiomatic semantics. Supported language features:
  4021 classes, interfaces, objects,virtual methods, static methods,
  4022 static/instance fields, arrays, access modifiers, definite
  4023 assignment, exceptions.
  4024 
  4025 
  4026 *** ZF ***
  4027 
  4028 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4029 universe, etc.);
  4030 
  4031 * Main ZF: virtually all theories converted to new-style format;
  4032 
  4033 
  4034 *** ML ***
  4035 
  4036 * Pure: Tactic.prove provides sane interface for internal proofs;
  4037 omits the infamous "standard" operation, so this is more appropriate
  4038 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4039 
  4040 * Pure: improved error reporting of simprocs;
  4041 
  4042 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4043 up simprocs;
  4044 
  4045 
  4046 *** Document preparation ***
  4047 
  4048 * uses \par instead of \\ for line breaks in theory text. This may
  4049 shift some page breaks in large documents. To get the old behaviour
  4050 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4051 
  4052 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4053 other packages
  4054 
  4055 * \<euro> now needs package babel/greek instead of marvosym (which
  4056 broke \Rightarrow)
  4057 
  4058 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4059 textcomp package)
  4060 
  4061 
  4062 
  4063 New in Isabelle2002 (March 2002)
  4064 --------------------------------
  4065 
  4066 *** Document preparation ***
  4067 
  4068 * greatly simplified document preparation setup, including more
  4069 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4070 instructive isatool mkdir; users should basically be able to get
  4071 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4072 users may run a separate document processing stage manually like this:
  4073 "isatool usedir -D output HOL Test && isatool document Test/output";
  4074 
  4075 * theory dependency graph may now be incorporated into documents;
  4076 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4077 with \includegraphics of LaTeX;
  4078 
  4079 * proper spacing of consecutive markup elements, especially text
  4080 blocks after section headings;
  4081 
  4082 * support bold style (for single symbols only), input syntax is like
  4083 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4084 
  4085 * \<bullet> is now output as bold \cdot by default, which looks much
  4086 better in printed text;
  4087 
  4088 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4089 note that these symbols are currently unavailable in Proof General /
  4090 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4091 
  4092 * isatool latex no longer depends on changed TEXINPUTS, instead
  4093 isatool document copies the Isabelle style files to the target
  4094 location;
  4095 
  4096 
  4097 *** Isar ***
  4098 
  4099 * Pure/Provers: improved proof by cases and induction;
  4100   - 'case' command admits impromptu naming of parameters (such as
  4101     "case (Suc n)");
  4102   - 'induct' method divinates rule instantiation from the inductive
  4103     claim; no longer requires excessive ?P bindings for proper
  4104     instantiation of cases;
  4105   - 'induct' method properly enumerates all possibilities of set/type
  4106     rules; as a consequence facts may be also passed through *type*
  4107     rules without further ado;
  4108   - 'induct' method now derives symbolic cases from the *rulified*
  4109     rule (before it used to rulify cases stemming from the internal
  4110     atomized version); this means that the context of a non-atomic
  4111     statement becomes is included in the hypothesis, avoiding the
  4112     slightly cumbersome show "PROP ?case" form;
  4113   - 'induct' may now use elim-style induction rules without chaining
  4114     facts, using ``missing'' premises from the goal state; this allows
  4115     rules stemming from inductive sets to be applied in unstructured
  4116     scripts, while still benefitting from proper handling of non-atomic
  4117     statements; NB: major inductive premises need to be put first, all
  4118     the rest of the goal is passed through the induction;
  4119   - 'induct' proper support for mutual induction involving non-atomic
  4120     rule statements (uses the new concept of simultaneous goals, see
  4121     below);
  4122   - append all possible rule selections, but only use the first
  4123     success (no backtracking);
  4124   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4125   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4126   - added 'print_induct_rules' (covered by help item in recent Proof
  4127     General versions);
  4128   - moved induct/cases attributes to Pure, methods to Provers;
  4129   - generic method setup instantiated for FOL and HOL;
  4130 
  4131 * Pure: support multiple simultaneous goal statements, for example
  4132 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4133 meta-level mechanism, this acts as if several individual goals had
  4134 been stated separately; in particular common proof methods need to be
  4135 repeated in order to cover all claims; note that a single elimination
  4136 step is *not* sufficient to establish the two conjunctions, so this
  4137 fails:
  4138 
  4139   assume "A & B" then have A and B ..   (*".." fails*)
  4140 
  4141 better use "obtain" in situations as above; alternative refer to
  4142 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4143 
  4144 * Pure: proper integration with ``locales''; unlike the original
  4145 version by Florian Kammller, Isar locales package high-level proof
  4146 contexts rather than raw logical ones (e.g. we admit to include
  4147 attributes everywhere); operations on locales include merge and
  4148 rename; support for implicit arguments (``structures''); simultaneous
  4149 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4150 some examples;
  4151 
  4152 * Pure: the following commands have been ``localized'', supporting a
  4153 target locale specification "(in name)": 'lemma', 'theorem',
  4154 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4155 stored both within the locale and at the theory level (exported and
  4156 qualified by the locale name);
  4157 
  4158 * Pure: theory goals may now be specified in ``long'' form, with
  4159 ad-hoc contexts consisting of arbitrary locale elements. for example
  4160 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4161 definitions may be given, too); the result is a meta-level rule with
  4162 the context elements being discharged in the obvious way;
  4163 
  4164 * Pure: new proof command 'using' allows to augment currently used
  4165 facts after a goal statement ('using' is syntactically analogous to
  4166 'apply', but acts on the goal's facts only); this allows chained facts
  4167 to be separated into parts given before and after a claim, as in
  4168 ``from a and b have C using d and e <proof>'';
  4169 
  4170 * Pure: renamed "antecedent" case to "rule_context";
  4171 
  4172 * Pure: new 'judgment' command records explicit information about the
  4173 object-logic embedding (used by several tools internally); no longer
  4174 use hard-wired "Trueprop";
  4175 
  4176 * Pure: added 'corollary' command;
  4177 
  4178 * Pure: fixed 'token_translation' command;
  4179 
  4180 * Pure: removed obsolete 'exported' attribute;
  4181 
  4182 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4183 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4184 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4185 
  4186 * Pure: method 'atomize' presents local goal premises as object-level
  4187 statements (atomic meta-level propositions); setup controlled via
  4188 rewrite rules declarations of 'atomize' attribute; example
  4189 application: 'induct' method with proper rule statements in improper
  4190 proof *scripts*;
  4191 
  4192 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4193 now consider the syntactic context of assumptions, giving a better
  4194 chance to get type-inference of the arguments right (this is
  4195 especially important for locales);
  4196 
  4197 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4198 mode;
  4199 
  4200 * Pure/obtain: the formal conclusion "thesis", being marked as
  4201 ``internal'', may no longer be reference directly in the text;
  4202 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4203 situations;
  4204 
  4205 * Pure: generic 'sym' attribute which declares a rule both as pure
  4206 'elim?' and for the 'symmetric' operation;
  4207 
  4208 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4209 text; the fixed correlation with particular command syntax has been
  4210 discontinued;
  4211 
  4212 * Pure: new method 'rules' is particularly well-suited for proof
  4213 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4214 but often produces more compact proof terms with less detours;
  4215 
  4216 * Pure/Provers/classical: simplified integration with pure rule
  4217 attributes and methods; the classical "intro?/elim?/dest?"
  4218 declarations coincide with the pure ones; the "rule" method no longer
  4219 includes classically swapped intros; "intro" and "elim" methods no
  4220 longer pick rules from the context; also got rid of ML declarations
  4221 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4222 INCOMPATIBILITY;
  4223 
  4224 * Provers/classical: attribute 'swapped' produces classical inversions
  4225 of introduction rules;
  4226 
  4227 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4228 rules instead of full simplifier context; 'iff' attribute handles
  4229 conditional rules;
  4230 
  4231 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4232 
  4233 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4234 "(permissive)" option to recover old behavior;
  4235 
  4236 * HOL: 'inductive' no longer features separate (collective) attributes
  4237 for 'intros' (was found too confusing);
  4238 
  4239 * HOL: properly declared induction rules less_induct and
  4240 wf_induct_rule;
  4241 
  4242 
  4243 *** HOL ***
  4244 
  4245 * HOL: moved over to sane numeral syntax; the new policy is as
  4246 follows:
  4247 
  4248   - 0 and 1 are polymorphic constants, which are defined on any
  4249   numeric type (nat, int, real etc.);
  4250 
  4251   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4252   binary representation internally;
  4253 
  4254   - type nat has special constructor Suc, and generally prefers Suc 0
  4255   over 1::nat and Suc (Suc 0) over 2::nat;
  4256 
  4257 This change may cause significant problems of INCOMPATIBILITY; here
  4258 are some hints on converting existing sources:
  4259 
  4260   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4261   entities, so expressions involving "-" (unary or binary minus) need
  4262   to be spaced properly;
  4263 
  4264   - existing occurrences of "1" may need to be constraint "1::nat" or
  4265   even replaced by Suc 0; similar for old "2";
  4266 
  4267   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4268 
  4269   - remove all special provisions on numerals in proofs;
  4270 
  4271 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4272 representation (depends on bin_arith_simps in the default context);
  4273 
  4274 * HOL: symbolic syntax for x^2 (numeral 2);
  4275 
  4276 * HOL: the class of all HOL types is now called "type" rather than
  4277 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4278 in axclass/classes, instance/arities, and (usually rare) occurrences
  4279 in typings (of consts etc.); internally the class is called
  4280 "HOL.type", ML programs should refer to HOLogic.typeS;
  4281 
  4282 * HOL/record package improvements:
  4283   - new derived operations "fields" to build a partial record section,
  4284     "extend" to promote a fixed record to a record scheme, and
  4285     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4286     declared as simp by default;
  4287   - shared operations ("more", "fields", etc.) now need to be always
  4288     qualified) --- potential INCOMPATIBILITY;
  4289   - removed "make_scheme" operations (use "make" with "extend") --
  4290     INCOMPATIBILITY;
  4291   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4292   - provides cases/induct rules for use with corresponding Isar
  4293     methods (for concrete records, record schemes, concrete more
  4294     parts, and schematic more parts -- in that order);
  4295   - internal definitions directly based on a light-weight abstract
  4296     theory of product types over typedef rather than datatype;
  4297 
  4298 * HOL: generic code generator for generating executable ML code from
  4299 specifications; specific support for HOL constructs such as inductive
  4300 datatypes and sets, as well as recursive functions; can be invoked
  4301 via 'generate_code' theory section;
  4302 
  4303 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4304 
  4305 * HOL: consolidated and renamed several theories.  In particular:
  4306         Ord.thy has been absorbed into HOL.thy
  4307         String.thy has been absorbed into List.thy
  4308 
  4309 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4310 (beware of argument permutation!);
  4311 
  4312 * HOL: linorder_less_split superseded by linorder_cases;
  4313 
  4314 * HOL/List: "nodups" renamed to "distinct";
  4315 
  4316 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4317 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4318   - Ex_def has changed, now need to use some_eq_ex
  4319 
  4320 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4321 in this (rare) case use:
  4322 
  4323   delSWrapper "split_all_tac"
  4324   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4325 
  4326 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4327 MAY FAIL;
  4328 
  4329 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4330 Isabelle's type classes, ^ on functions and relations has too general
  4331 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4332 necessary to attach explicit type constraints;
  4333 
  4334 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4335 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4336 renamed accordingly (eg "compI" -> "rel_compI").
  4337 
  4338 * HOL: syntax translations now work properly with numerals and records
  4339 expressions;
  4340 
  4341 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4342 of "lam" -- INCOMPATIBILITY;
  4343 
  4344 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4345 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4346 renamed "Product_Type.unit";
  4347 
  4348 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4349 
  4350 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4351 the "cases" method);
  4352 
  4353 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4354 Florian Kammller);
  4355 
  4356 * HOL/IMP: updated and converted to new-style theory format; several
  4357 parts turned into readable document, with proper Isar proof texts and
  4358 some explanations (by Gerwin Klein);
  4359 
  4360 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4361 
  4362 * HOL-Hyperreal is now a logic image;
  4363 
  4364 
  4365 *** HOLCF ***
  4366 
  4367 * Isar: consts/constdefs supports mixfix syntax for continuous
  4368 operations;
  4369 
  4370 * Isar: domain package adapted to new-style theory format, e.g. see
  4371 HOLCF/ex/Dnat.thy;
  4372 
  4373 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4374 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4375 lift.induct_tac, always use UU instead of Undef;
  4376 
  4377 * HOLCF/IMP: updated and converted to new-style theory;
  4378 
  4379 
  4380 *** ZF ***
  4381 
  4382 * Isar: proper integration of logic-specific tools and packages,
  4383 including theory commands '(co)inductive', '(co)datatype',
  4384 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4385 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4386 
  4387 * theory Main no longer includes AC; for the Axiom of Choice, base
  4388 your theory on Main_ZFC;
  4389 
  4390 * the integer library now covers quotients and remainders, with many
  4391 laws relating division to addition, multiplication, etc.;
  4392 
  4393 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4394 typeless version of the formalism;
  4395 
  4396 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4397 format;
  4398 
  4399 * ZF/Induct: new directory for examples of inductive definitions,
  4400 including theory Multiset for multiset orderings; converted to
  4401 new-style theory format;
  4402 
  4403 * ZF: many new theorems about lists, ordinals, etc.;
  4404 
  4405 
  4406 *** General ***
  4407 
  4408 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4409 variable proof controls level of detail: 0 = no proofs (only oracle
  4410 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4411 also ref manual for further ML interfaces;
  4412 
  4413 * Pure/axclass: removed obsolete ML interface
  4414 goal_subclass/goal_arity;
  4415 
  4416 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4417 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4418 separate tokens, so expressions involving minus need to be spaced
  4419 properly;
  4420 
  4421 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4422 rather than "infixl" or "infixr";
  4423 
  4424 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4425 sort constraint specifications in type inference; e.g. "x::_::foo"
  4426 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4427 type variable);
  4428 
  4429 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4430 control output of nested => (types); the default behavior is
  4431 "type_brackets";
  4432 
  4433 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4434 tokens into AST constants;
  4435 
  4436 * Pure/syntax: prefer later declarations of translations and print
  4437 translation functions; potential INCOMPATIBILITY: need to reverse
  4438 multiple declarations for same syntax element constant;
  4439 
  4440 * Pure/show_hyps reset by default (in accordance to existing Isar
  4441 practice);
  4442 
  4443 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4444 addSafter;
  4445 
  4446 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4447 as well;
  4448 
  4449 * system: tested support for MacOS X; should be able to get Isabelle +
  4450 Proof General to work in a plain Terminal after installing Poly/ML
  4451 (e.g. from the Isabelle distribution area) and GNU bash alone
  4452 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4453 support requires further installations, e.g. from
  4454 http://fink.sourceforge.net/);
  4455 
  4456 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4457 
  4458 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4459 of 40 MB), cf. ML_OPTIONS;
  4460 
  4461 * system: Proof General keywords specification is now part of the
  4462 Isabelle distribution (see etc/isar-keywords.el);
  4463 
  4464 * system: support for persistent Proof General sessions (refrain from
  4465 outdating all loaded theories on startup); user may create writable
  4466 logic images like this: ``isabelle -q HOL Test'';
  4467 
  4468 * system: smart selection of Isabelle process versus Isabelle
  4469 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4470 run both "isabelle" and "Isabelle" even if file names are badly
  4471 damaged (executable inspects the case of the first letter of its own
  4472 name); added separate "isabelle-process" and "isabelle-interface";
  4473 
  4474 * system: refrain from any attempt at filtering input streams; no
  4475 longer support ``8bit'' encoding of old isabelle font, instead proper
  4476 iso-latin characters may now be used; the related isatools
  4477 "symbolinput" and "nonascii" have disappeared as well;
  4478 
  4479 * system: removed old "xterm" interface (the print modes "xterm" and
  4480 "xterm_color" are still available for direct use in a suitable
  4481 terminal);
  4482 
  4483 
  4484 
  4485 New in Isabelle99-2 (February 2001)
  4486 -----------------------------------
  4487 
  4488 *** Overview of INCOMPATIBILITIES ***
  4489 
  4490 * HOL: please note that theories in the Library and elsewhere often use the
  4491 new-style (Isar) format; to refer to their theorems in an ML script you must
  4492 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4493 
  4494 * HOL: inductive package no longer splits induction rule aggressively,
  4495 but only as far as specified by the introductions given; the old
  4496 format may be recovered via ML function complete_split_rule or attribute
  4497 'split_rule (complete)';
  4498 
  4499 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4500 gfp_Tarski to gfp_unfold;
  4501 
  4502 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4503 
  4504 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4505 relation); infix "^^" has been renamed "``"; infix "``" has been
  4506 renamed "`"; "univalent" has been renamed "single_valued";
  4507 
  4508 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4509 operation;
  4510 
  4511 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4512 
  4513 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4514 
  4515 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4516 consequence, it is no longer monotonic wrt. the local goal context
  4517 (which is now passed through the inductive cases);
  4518 
  4519 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4520 \<gg> to \<ggreater>;
  4521 
  4522 
  4523 *** Document preparation ***
  4524 
  4525 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4526 available: are "it" for near math-mode best-style output, "sl" for
  4527 slanted text style, and "tt" for plain type-writer; if no
  4528 \isabellestyle command is given, output is according to slanted
  4529 type-writer);
  4530 
  4531 * support sub/super scripts (for single symbols only), input syntax is
  4532 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4533 
  4534 * some more standard symbols; see Appendix A of the system manual for
  4535 the complete list of symbols defined in isabellesym.sty;
  4536 
  4537 * improved isabelle style files; more abstract symbol implementation
  4538 (should now use \isamath{...} and \isatext{...} in custom symbol
  4539 definitions);
  4540 
  4541 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4542 state; Note that presentation of goal states does not conform to
  4543 actual human-readable proof documents.  Please do not include goal
  4544 states into document output unless you really know what you are doing!
  4545 
  4546 * proper indentation of antiquoted output with proportional LaTeX
  4547 fonts;
  4548 
  4549 * no_document ML operator temporarily disables LaTeX document
  4550 generation;
  4551 
  4552 * isatool unsymbolize tunes sources for plain ASCII communication;
  4553 
  4554 
  4555 *** Isar ***
  4556 
  4557 * Pure: Isar now suffers initial goal statements to contain unbound
  4558 schematic variables (this does not conform to actual readable proof
  4559 documents, due to unpredictable outcome and non-compositional proof
  4560 checking); users who know what they are doing may use schematic goals
  4561 for Prolog-style synthesis of proven results;
  4562 
  4563 * Pure: assumption method (an implicit finishing) now handles actual
  4564 rules as well;
  4565 
  4566 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4567 initial goal, declare "that" only as Pure intro (only for single
  4568 steps); the "that" rule assumption may now be involved in implicit
  4569 finishing, thus ".." becomes a feasible for trivial obtains;
  4570 
  4571 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4572 instance proofs may be performed by "..";
  4573 
  4574 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4575 statements as well;
  4576 
  4577 * Pure: more robust selection of calculational rules;
  4578 
  4579 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4580 rule (as well as the assumption rule);
  4581 
  4582 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4583 lemmas, using the graph browser tool;
  4584 
  4585 * Pure: predict failure of "show" in interactive mode;
  4586 
  4587 * Pure: 'thms_containing' now takes actual terms as arguments;
  4588 
  4589 * HOL: improved method 'induct' --- now handles non-atomic goals
  4590 (potential INCOMPATIBILITY); tuned error handling;
  4591 
  4592 * HOL: cases and induct rules now provide explicit hints about the
  4593 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4594 any remaining facts are inserted into the goal verbatim;
  4595 
  4596 * HOL: local contexts (aka cases) may now contain term bindings as
  4597 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4598 the result to be shown in each case;
  4599 
  4600 * HOL: added 'recdef_tc' command;
  4601 
  4602 * isatool convert assists in eliminating legacy ML scripts;
  4603 
  4604 
  4605 *** HOL ***
  4606 
  4607 * HOL/Library: a collection of generic theories to be used together
  4608 with main HOL; the theory loader path already includes this directory
  4609 by default; the following existing theories have been moved here:
  4610 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4611 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4612 
  4613 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4614 modelling and verification task performed in Isabelle/HOL +
  4615 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4616 
  4617 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4618 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4619 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4620 'domain', this makes the theory consistent with mathematical
  4621 literature;
  4622 
  4623 * HOL basics: added overloaded operations "inverse" and "divide"
  4624 (infix "/"), syntax for generic "abs" operation, generic summation
  4625 operator \<Sum>;
  4626 
  4627 * HOL/typedef: simplified package, provide more useful rules (see also
  4628 HOL/subset.thy);
  4629 
  4630 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4631 now expressed as a proper nested rule (old-style tactic scripts may
  4632 require atomize_strip_tac to cope with non-atomic premises);
  4633 
  4634 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4635 to "split_conv" (old name still available for compatibility);
  4636 
  4637 * HOL: improved concrete syntax for strings (e.g. allows translation
  4638 rules with string literals);
  4639 
  4640 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4641  and Fleuriot's mechanization of analysis, including the transcendental
  4642  functions for the reals;
  4643 
  4644 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4645 
  4646 
  4647 *** CTT ***
  4648 
  4649 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4650 "lam" is displayed as TWO lambda-symbols
  4651 
  4652 * CTT: theory Main now available, containing everything (that is, Bool
  4653 and Arith);
  4654 
  4655 
  4656 *** General ***
  4657 
  4658 * Pure: the Simplifier has been implemented properly as a derived rule
  4659 outside of the actual kernel (at last!); the overall performance
  4660 penalty in practical applications is about 50%, while reliability of
  4661 the Isabelle inference kernel has been greatly improved;
  4662 
  4663 * print modes "brackets" and "no_brackets" control output of nested =>
  4664 (types) and ==> (props); the default behaviour is "brackets";
  4665 
  4666 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4667 as assumptions as well;
  4668 
  4669 * system: support Poly/ML 4.0;
  4670 
  4671 * system: isatool install handles KDE version 1 or 2;
  4672 
  4673 
  4674 
  4675 New in Isabelle99-1 (October 2000)
  4676 ----------------------------------
  4677 
  4678 *** Overview of INCOMPATIBILITIES ***
  4679 
  4680 * HOL: simplification of natural numbers is much changed; to partly
  4681 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4682 issue the following ML commands:
  4683 
  4684   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4685   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4686 
  4687 * HOL: simplification no longer dives into case-expressions; this is
  4688 controlled by "t.weak_case_cong" for each datatype t;
  4689 
  4690 * HOL: nat_less_induct renamed to less_induct;
  4691 
  4692 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4693 fixsome to patch .thy and .ML sources automatically;
  4694 
  4695   select_equality  -> some_equality
  4696   select_eq_Ex     -> some_eq_ex
  4697   selectI2EX       -> someI2_ex
  4698   selectI2         -> someI2
  4699   selectI          -> someI
  4700   select1_equality -> some1_equality
  4701   Eps_sym_eq       -> some_sym_eq_trivial
  4702   Eps_eq           -> some_eq_trivial
  4703 
  4704 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4705 
  4706 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4707 instead);
  4708 
  4709 * HOL: the recursion equations generated by 'recdef' are now called
  4710 f.simps instead of f.rules;
  4711 
  4712 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4713 
  4714 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4715 sometimes be needed;
  4716 
  4717 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4718 
  4719 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4720 
  4721 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4722 product is now "<*>" instead of "Times"; the lexicographic product is
  4723 now "<*lex*>" instead of "**";
  4724 
  4725 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4726 of main HOL, but was unused); better use HOL's datatype package;
  4727 
  4728 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4729 the old syntax may be recovered as follows:
  4730 
  4731   syntax (symbols)
  4732     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4733       (infixl "\\<oplus>" 100)
  4734 
  4735 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4736 
  4737 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4738 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4739 internally;
  4740 
  4741 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4742 changed from A/r to A//r;
  4743 
  4744 * ZF: new treatment of arithmetic (nat & int) may break some old
  4745 proofs;
  4746 
  4747 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4748 rulify -> rule_format, elimify -> elim_format, ...);
  4749 
  4750 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4751 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4752 should have to change intro!! to intro? only); replaced "delrule" by
  4753 "rule del";
  4754 
  4755 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4756 
  4757 * Provers: strengthened force_tac by using new first_best_tac;
  4758 
  4759 * LaTeX document preparation: several changes of isabelle.sty (see
  4760 lib/texinputs);
  4761 
  4762 
  4763 *** Document preparation ***
  4764 
  4765 * formal comments (text blocks etc.) in new-style theories may now
  4766 contain antiquotations of thm/prop/term/typ/text to be presented
  4767 according to latex print mode; concrete syntax is like this:
  4768 @{term[show_types] "f(x) = a + x"};
  4769 
  4770 * isatool mkdir provides easy setup of Isabelle session directories,
  4771 including proper document sources;
  4772 
  4773 * generated LaTeX sources are now deleted after successful run
  4774 (isatool document -c); may retain a copy somewhere else via -D option
  4775 of isatool usedir;
  4776 
  4777 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4778 style files, achieving self-contained LaTeX sources and simplifying
  4779 LaTeX debugging;
  4780 
  4781 * old-style theories now produce (crude) LaTeX output as well;
  4782 
  4783 * browser info session directories are now self-contained (may be put
  4784 on WWW server seperately); improved graphs of nested sessions; removed
  4785 graph for 'all sessions';
  4786 
  4787 * several improvements in isabelle style files; \isabellestyle{it}
  4788 produces fake math mode output; \isamarkupheader is now \section by
  4789 default; see lib/texinputs/isabelle.sty etc.;
  4790 
  4791 
  4792 *** Isar ***
  4793 
  4794 * Isar/Pure: local results and corresponding term bindings are now
  4795 subject to Hindley-Milner polymorphism (similar to ML); this
  4796 accommodates incremental type-inference very nicely;
  4797 
  4798 * Isar/Pure: new derived language element 'obtain' supports
  4799 generalized existence reasoning;
  4800 
  4801 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4802 support accumulation of results, without applying any rules yet;
  4803 useful to collect intermediate results without explicit name
  4804 references, and for use with transitivity rules with more than 2
  4805 premises;
  4806 
  4807 * Isar/Pure: scalable support for case-analysis type proofs: new
  4808 'case' language element refers to local contexts symbolically, as
  4809 produced by certain proof methods; internally, case names are attached
  4810 to theorems as "tags";
  4811 
  4812 * Isar/Pure: theory command 'hide' removes declarations from
  4813 class/type/const name spaces;
  4814 
  4815 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4816 indicate potential overloading;
  4817 
  4818 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4819 
  4820 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4821 "{a,b,c}" instead of {a,b,c};
  4822 
  4823 * Isar/Pure now provides its own version of intro/elim/dest
  4824 attributes; useful for building new logics, but beware of confusion
  4825 with the version in Provers/classical;
  4826 
  4827 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4828 case name 'antecedent';
  4829 
  4830 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4831 to the current context is now done automatically);
  4832 
  4833 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4834 for definining proof methods in ML;
  4835 
  4836 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4837 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4838 most cases, one should have to change intro!! to intro? only);
  4839 replaced "delrule" by "rule del";
  4840 
  4841 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4842 'symmetric' attribute (the latter supercedes [RS sym]);
  4843 
  4844 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4845 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4846 well (including splits);
  4847 
  4848 * Isar/Provers: Simplifier and Classical methods now support all kind
  4849 of modifiers used in the past, including 'cong', 'iff', etc.
  4850 
  4851 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4852 of Simplifier and Classical reasoner);
  4853 
  4854 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4855 now support named cases; major packages (inductive, datatype, primrec,
  4856 recdef) support case names and properly name parameters;
  4857 
  4858 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4859 monotonicity conditions are extracted to be proven at end of
  4860 calculations;
  4861 
  4862 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4863 method anyway;
  4864 
  4865 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4866 split_if split_if_asm; datatype package provides theorems foo.splits =
  4867 foo.split foo.split_asm for each datatype;
  4868 
  4869 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4870 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4871 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4872 use "(cases (simplified))" method in proper proof texts);
  4873 
  4874 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4875 
  4876 * Isar: names of theorems etc. may be natural numbers as well;
  4877 
  4878 * Isar: 'pr' command: optional arguments for goals_limit and
  4879 ProofContext.prems_limit; no longer prints theory contexts, but only
  4880 proof states;
  4881 
  4882 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4883 additional print modes to be specified; e.g. "pr(latex)" will print
  4884 proof state according to the Isabelle LaTeX style;
  4885 
  4886 * Isar: improved support for emulating tactic scripts, including proof
  4887 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4888 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4889 (for HOL datatypes);
  4890 
  4891 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4892 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4893 'proof method scripts' have to be in depth-first order;
  4894 
  4895 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4896 
  4897 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4898 should instead use individual commands for printing items
  4899 (print_commands, print_methods etc.);
  4900 
  4901 * Isar: added 'nothing' --- the empty list of theorems;
  4902 
  4903 
  4904 *** HOL ***
  4905 
  4906 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4907 corresponding virtual machine and a specification of its bytecode
  4908 verifier and a lightweight bytecode verifier, including proofs of
  4909 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4910 Cornelia Pusch (see also the homepage of project Bali at
  4911 http://isabelle.in.tum.de/Bali/);
  4912 
  4913 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4914 Clemens Ballarin;
  4915 
  4916 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4917 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4918 Rasmussen;
  4919 
  4920 * HOL/Lattice: fundamental concepts of lattice theory and order
  4921 structures, including duals, properties of bounds versus algebraic
  4922 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4923 Theorem for complete lattices etc.; may also serve as a demonstration
  4924 for abstract algebraic reasoning using axiomatic type classes, and
  4925 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4926 
  4927 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4928 von Oheimb;
  4929 
  4930 * HOL/IMPP: extension of IMP with local variables and mutually
  4931 recursive procedures, by David von Oheimb;
  4932 
  4933 * HOL/Lambda: converted into new-style theory and document;
  4934 
  4935 * HOL/ex/Multiquote: example of multiple nested quotations and
  4936 anti-quotations -- basically a generalized version of de-Bruijn
  4937 representation; very useful in avoiding lifting of operations;
  4938 
  4939 * HOL/record: added general record equality rule to simpset; fixed
  4940 select-update simplification procedure to handle extended records as
  4941 well; admit "r" as field name;
  4942 
  4943 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4944 other numeric types and also as the identity of groups, rings, etc.;
  4945 
  4946 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4947 Types nat and int belong to this axclass;
  4948 
  4949 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4950    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4951    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4952   two terms #m*u and #n*u are replaced by #(m+n)*u
  4953     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4954   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4955     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4956 
  4957 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4958 powerful prover for predicate logic but knows nothing of clasets; see
  4959 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4960 
  4961 * HOL: new version of "case_tac" subsumes both boolean case split and
  4962 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4963 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4964 
  4965 * HOL: simplification no longer dives into case-expressions: only the
  4966 selector expression is simplified, but not the remaining arms; to
  4967 enable full simplification of case-expressions for datatype t, you may
  4968 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4969 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4970 
  4971 * HOL/recdef: the recursion equations generated by 'recdef' for
  4972 function 'f' are now called f.simps instead of f.rules; if all
  4973 termination conditions are proved automatically, these simplification
  4974 rules are added to the simpset, as in primrec; rules may be named
  4975 individually as well, resulting in a separate list of theorems for
  4976 each equation;
  4977 
  4978 * HOL/While is a new theory that provides a while-combinator. It
  4979 permits the definition of tail-recursive functions without the
  4980 provision of a termination measure. The latter is necessary once the
  4981 invariant proof rule for while is applied.
  4982 
  4983 * HOL: new (overloaded) notation for the set of elements below/above
  4984 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4985 
  4986 * HOL: theorems impI, allI, ballI bound as "strip";
  4987 
  4988 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4989 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4990 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4991 
  4992 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4993 
  4994 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4995 main HOL, but was unused);
  4996 
  4997 * HOL: fewer consts declared as global (e.g. have to refer to
  4998 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4999 
  5000 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5001 in case of overlap with user translations (e.g. judgements over
  5002 tuples); (note that the underlying logical represenation is still
  5003 bogus);
  5004 
  5005 
  5006 *** ZF ***
  5007 
  5008 * ZF: simplification automatically cancels common terms in arithmetic
  5009 expressions over nat and int;
  5010 
  5011 * ZF: new treatment of nat to minimize type-checking: all operators
  5012 coerce their operands to a natural number using the function natify,
  5013 making the algebraic laws unconditional;
  5014 
  5015 * ZF: as above, for int: operators coerce their operands to an integer
  5016 using the function intify;
  5017 
  5018 * ZF: the integer library now contains many of the usual laws for the
  5019 orderings, including $<=, and monotonicity laws for $+ and $*;
  5020 
  5021 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5022 simplification;
  5023 
  5024 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5025 to the simplifier and classical reasoner simultaneously;
  5026 
  5027 
  5028 *** General ***
  5029 
  5030 * Provers: blast_tac now handles actual object-logic rules as
  5031 assumptions; note that auto_tac uses blast_tac internally as well;
  5032 
  5033 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5034 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5035 
  5036 * Provers: delrules now handles destruct rules as well (no longer need
  5037 explicit make_elim);
  5038 
  5039 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5040   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5041 use instead the strong form,
  5042   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5043 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5044 from destruct-rules;
  5045 
  5046 * Provers: Simplifier.easy_setup provides a fast path to basic
  5047 Simplifier setup for new object-logics;
  5048 
  5049 * Pure: AST translation rules no longer require constant head on LHS;
  5050 
  5051 * Pure: improved name spaces: ambiguous output is qualified; support
  5052 for hiding of names;
  5053 
  5054 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5055 XSYMBOL_HOME; no longer need to do manual configuration in most
  5056 situations;
  5057 
  5058 * system: compression of ML heaps images may now be controlled via -c
  5059 option of isabelle and isatool usedir (currently only observed by
  5060 Poly/ML);
  5061 
  5062 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5063 useful for remote X11);
  5064 
  5065 * system: provide TAGS file for Isabelle sources;
  5066 
  5067 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5068 order;
  5069 
  5070 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5071 timing flag supersedes proof_timing and Toplevel.trace;
  5072 
  5073 * ML: new combinators |>> and |>>> for incremental transformations
  5074 with secondary results (e.g. certain theory extensions):
  5075 
  5076 * ML: PureThy.add_defs gets additional argument to indicate potential
  5077 overloading (usually false);
  5078 
  5079 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5080 results;
  5081 
  5082 
  5083 
  5084 New in Isabelle99 (October 1999)
  5085 --------------------------------
  5086 
  5087 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5088 
  5089 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5090 are no longer simplified.  (This allows the simplifier to unfold recursive
  5091 functional programs.)  To restore the old behaviour, declare
  5092 
  5093     Delcongs [if_weak_cong];
  5094 
  5095 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5096 complement;
  5097 
  5098 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5099 
  5100 * HOL/datatype: mutual_induct_tac no longer exists --
  5101   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5102 
  5103 * HOL/typedef: fixed type inference for representing set; type
  5104 arguments now have to occur explicitly on the rhs as type constraints;
  5105 
  5106 * ZF: The con_defs part of an inductive definition may no longer refer
  5107 to constants declared in the same theory;
  5108 
  5109 * HOL, ZF: the function mk_cases, generated by the inductive
  5110 definition package, has lost an argument.  To simplify its result, it
  5111 uses the default simpset instead of a supplied list of theorems.
  5112 
  5113 * HOL/List: the constructors of type list are now Nil and Cons;
  5114 
  5115 * Simplifier: the type of the infix ML functions
  5116         setSSolver addSSolver setSolver addSolver
  5117 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5118 for packaging solvers. A solver is created via
  5119         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5120 where the string argument is only a comment.
  5121 
  5122 
  5123 *** Proof tools ***
  5124 
  5125 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5126 decision procedure for linear arithmetic. Currently it is used for
  5127 types `nat', `int', and `real' in HOL (see below); it can, should and
  5128 will be instantiated for other types and logics as well.
  5129 
  5130 * The simplifier now accepts rewrite rules with flexible heads, eg
  5131      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5132   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5133   matching.
  5134 
  5135 
  5136 *** General ***
  5137 
  5138 * New Isabelle/Isar subsystem provides an alternative to traditional
  5139 tactical theorem proving; together with the ProofGeneral/isar user
  5140 interface it offers an interactive environment for developing human
  5141 readable proof documents (Isar == Intelligible semi-automated
  5142 reasoning); for further information see isatool doc isar-ref,
  5143 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5144 
  5145 * improved and simplified presentation of theories: better HTML markup
  5146 (including colors), graph views in several sizes; isatool usedir now
  5147 provides a proper interface for user theories (via -P option); actual
  5148 document preparation based on (PDF)LaTeX is available as well (for
  5149 new-style theories only); see isatool doc system for more information;
  5150 
  5151 * native support for Proof General, both for classic Isabelle and
  5152 Isabelle/Isar;
  5153 
  5154 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5155 using the graph browser tool;
  5156 
  5157 * Isabelle manuals now also available as PDF;
  5158 
  5159 * theory loader rewritten from scratch (may not be fully
  5160 bug-compatible); old loadpath variable has been replaced by show_path,
  5161 add_path, del_path, reset_path functions; new operations such as
  5162 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5163 isatool doc ref);
  5164 
  5165 * improved isatool install: option -k creates KDE application icon,
  5166 option -p DIR installs standalone binaries;
  5167 
  5168 * added ML_PLATFORM setting (useful for cross-platform installations);
  5169 more robust handling of platform specific ML images for SML/NJ;
  5170 
  5171 * the settings environment is now statically scoped, i.e. it is never
  5172 created again in sub-processes invoked from isabelle, isatool, or
  5173 Isabelle;
  5174 
  5175 * path element specification '~~' refers to '$ISABELLE_HOME';
  5176 
  5177 * in locales, the "assumes" and "defines" parts may be omitted if
  5178 empty;
  5179 
  5180 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5181 long arrows);
  5182 
  5183 * new print_mode "HTML";
  5184 
  5185 * new flag show_tags controls display of tags of theorems (which are
  5186 basically just comments that may be attached by some tools);
  5187 
  5188 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5189 mode and goal output format:
  5190 
  5191 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5192 244c244
  5193 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5194 ---
  5195 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5196 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5197 181c181
  5198 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5199 ---
  5200 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5201 
  5202 * function bind_thms stores lists of theorems (cf. bind_thm);
  5203 
  5204 * new shorthand tactics ftac, eatac, datac, fatac;
  5205 
  5206 * qed (and friends) now accept "" as result name; in that case the
  5207 theorem is not stored, but proper checks and presentation of the
  5208 result still apply;
  5209 
  5210 * theorem database now also indexes constants "Trueprop", "all",
  5211 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5212 
  5213 
  5214 *** HOL ***
  5215 
  5216 ** HOL arithmetic **
  5217 
  5218 * There are now decision procedures for linear arithmetic over nat and
  5219 int:
  5220 
  5221 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5222 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5223 are treated as atomic; subformulae not involving type `nat' or `int'
  5224 are ignored; quantified subformulae are ignored unless they are
  5225 positive universal or negative existential. The tactic has to be
  5226 invoked by hand and can be a little bit slow. In particular, the
  5227 running time is exponential in the number of occurrences of `min' and
  5228 `max', and `-' on `nat'.
  5229 
  5230 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5231 (negated) (in)equalities among the premises and the conclusion into
  5232 account (i.e. no compound formulae) and does not know about `min' and
  5233 `max', and `-' on `nat'. It is fast and is used automatically by the
  5234 simplifier.
  5235 
  5236 NB: At the moment, these decision procedures do not cope with mixed
  5237 nat/int formulae where the two parts interact, such as `m < n ==>
  5238 int(m) < int(n)'.
  5239 
  5240 * HOL/Numeral provides a generic theory of numerals (encoded
  5241 efficiently as bit strings); setup for types nat/int/real is in place;
  5242 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5243 int, existing theories and proof scripts may require a few additional
  5244 type constraints;
  5245 
  5246 * integer division and remainder can now be performed on constant
  5247 arguments;
  5248 
  5249 * many properties of integer multiplication, division and remainder
  5250 are now available;
  5251 
  5252 * An interface to the Stanford Validity Checker (SVC) is available through the
  5253 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5254 are proved automatically.  SVC must be installed separately, and its results
  5255 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5256 invocation of the underlying oracle).  For SVC see
  5257   http://verify.stanford.edu/SVC
  5258 
  5259 * IsaMakefile: the HOL-Real target now builds an actual image;
  5260 
  5261 
  5262 ** HOL misc **
  5263 
  5264 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5265 (in Isabelle/Isar) -- by Gertrud Bauer;
  5266 
  5267 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5268 analysis for assembly languages with subtypes;
  5269 
  5270 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5271 -- avoids syntactic ambiguities and treats state, transition, and
  5272 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5273 changed syntax and (many) tactics;
  5274 
  5275 * HOL/inductive: Now also handles more general introduction rules such
  5276   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5277   theorems are now maintained within the theory (maintained via the
  5278   "mono" attribute);
  5279 
  5280 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5281   (using function types) such as
  5282 
  5283   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5284 
  5285 * HOL/record: record_simproc (part of the default simpset) takes care
  5286 of selectors applied to updated records; record_split_tac is no longer
  5287 part of the default claset; update_defs may now be removed from the
  5288 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5289 
  5290   claset_ref () := claset() addSWrapper record_split_wrapper;
  5291   Delsimprocs [record_simproc]
  5292 
  5293 * HOL/typedef: fixed type inference for representing set; type
  5294 arguments now have to occur explicitly on the rhs as type constraints;
  5295 
  5296 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5297 names rather than an ML expression;
  5298 
  5299 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5300 supplied later.  Program schemes can be defined, such as
  5301     "While B C s = (if B s then While B C (C s) else s)"
  5302 where the well-founded relation can be chosen after B and C have been given.
  5303 
  5304 * HOL/List: the constructors of type list are now Nil and Cons;
  5305 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5306 course, ML tools referring to List.list.op # etc. have to be adapted;
  5307 
  5308 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5309 disabled by default; run isabelle with option -m HOL to get back to
  5310 the original Gordon/HOL-style output;
  5311 
  5312 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5313 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5314 
  5315 * HOL basic syntax simplified (more orthogonal): all variants of
  5316 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5317 Eps operator is provided as well: "SOME x. P[x]";
  5318 
  5319 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5320 
  5321 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5322 thus available for user theories;
  5323 
  5324 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5325 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5326 time;
  5327 
  5328 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5329 several times and then mp;
  5330 
  5331 
  5332 *** LK ***
  5333 
  5334 * the notation <<...>> is now available as a notation for sequences of
  5335 formulas;
  5336 
  5337 * the simplifier is now installed
  5338 
  5339 * the axiom system has been generalized (thanks to Soren Heilmann)
  5340 
  5341 * the classical reasoner now has a default rule database
  5342 
  5343 
  5344 *** ZF ***
  5345 
  5346 * new primrec section allows primitive recursive functions to be given
  5347 directly (as in HOL) over datatypes and the natural numbers;
  5348 
  5349 * new tactics induct_tac and exhaust_tac for induction (or case
  5350 analysis) over datatypes and the natural numbers;
  5351 
  5352 * the datatype declaration of type T now defines the recursor T_rec;
  5353 
  5354 * simplification automatically does freeness reasoning for datatype
  5355 constructors;
  5356 
  5357 * automatic type-inference, with AddTCs command to insert new
  5358 type-checking rules;
  5359 
  5360 * datatype introduction rules are now added as Safe Introduction rules
  5361 to the claset;
  5362 
  5363 * the syntax "if P then x else y" is now available in addition to
  5364 if(P,x,y);
  5365 
  5366 
  5367 *** Internal programming interfaces ***
  5368 
  5369 * tuned simplifier trace output; new flag debug_simp;
  5370 
  5371 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5372 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5373 
  5374 * AxClass.axclass_tac lost the theory argument;
  5375 
  5376 * tuned current_goals_markers semantics: begin / end goal avoids
  5377 printing empty lines;
  5378 
  5379 * removed prs and prs_fn hook, which was broken because it did not
  5380 include \n in its semantics, forcing writeln to add one
  5381 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5382 string -> unit if you really want to output text without newline;
  5383 
  5384 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5385 plain output, interface builders may have to enable 'isabelle_font'
  5386 mode to get Isabelle font glyphs as before;
  5387 
  5388 * refined token_translation interface; INCOMPATIBILITY: output length
  5389 now of type real instead of int;
  5390 
  5391 * theory loader actions may be traced via new ThyInfo.add_hook
  5392 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5393 your own database of information attached to *whole* theories -- as
  5394 opposed to intra-theory data slots offered via TheoryDataFun;
  5395 
  5396 * proper handling of dangling sort hypotheses (at last!);
  5397 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5398 extra sort hypotheses that can be witnessed from the type signature;
  5399 the force_strip_shyps flag is gone, any remaining shyps are simply
  5400 left in the theorem (with a warning issued by strip_shyps_warning);
  5401 
  5402 
  5403 
  5404 New in Isabelle98-1 (October 1998)
  5405 ----------------------------------
  5406 
  5407 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5408 
  5409 * several changes of automated proof tools;
  5410 
  5411 * HOL: major changes to the inductive and datatype packages, including
  5412 some minor incompatibilities of theory syntax;
  5413 
  5414 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5415 called `inj_on';
  5416 
  5417 * HOL: removed duplicate thms in Arith:
  5418   less_imp_add_less  should be replaced by  trans_less_add1
  5419   le_imp_add_le      should be replaced by  trans_le_add1
  5420 
  5421 * HOL: unary minus is now overloaded (new type constraints may be
  5422 required);
  5423 
  5424 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5425 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5426 now taken as an integer constant.
  5427 
  5428 * Pure: ML function 'theory_of' renamed to 'theory';
  5429 
  5430 
  5431 *** Proof tools ***
  5432 
  5433 * Simplifier:
  5434   1. Asm_full_simp_tac is now more aggressive.
  5435      1. It will sometimes reorient premises if that increases their power to
  5436         simplify.
  5437      2. It does no longer proceed strictly from left to right but may also
  5438         rotate premises to achieve further simplification.
  5439      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5440      old Asm_full_simp_tac in that it does not rotate premises.
  5441   2. The simplifier now knows a little bit about nat-arithmetic.
  5442 
  5443 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5444 allows for selected deletion of wrappers, by introduction of names for
  5445 wrapper functionals.  This implies that addbefore, addSbefore,
  5446 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5447 and that adding two tactics with the same name overwrites the first
  5448 one (emitting a warning).
  5449   type wrapper = (int -> tactic) -> (int -> tactic)
  5450   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5451   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5452   delWrapper, delSWrapper: claset *  string            -> claset
  5453   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5454 
  5455 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5456 semantics; addbefore now affects only the unsafe part of step_tac
  5457 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5458 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5459 by Force_tac;
  5460 
  5461 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5462 compWrapper; added safe wrapper (and access functions for it);
  5463 
  5464 * HOL/split_all_tac is now much faster and fails if there is nothing
  5465 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5466 and the names of the automatically generated variables have changed.
  5467 split_all_tac has moved within claset() from unsafe wrappers to safe
  5468 wrappers, which means that !!-bound variables are split much more
  5469 aggressively, and safe_tac and clarify_tac now split such variables.
  5470 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5471 Note: the same holds for record_split_tac, which does the job of
  5472 split_all_tac for record fields.
  5473 
  5474 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5475 permanently to the default simpset using Addsplits just like
  5476 Addsimps. They can be removed via Delsplits just like
  5477 Delsimps. Lower-case versions are also available.
  5478 
  5479 * HOL/Simplifier: The rule split_if is now part of the default
  5480 simpset. This means that the simplifier will eliminate all occurrences
  5481 of if-then-else in the conclusion of a goal. To prevent this, you can
  5482 either remove split_if completely from the default simpset by
  5483 `Delsplits [split_if]' or remove it in a specific call of the
  5484 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5485 other case splitting rules to/from the default simpset: every datatype
  5486 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5487 t is the name of the datatype).
  5488 
  5489 * Classical reasoner / Simplifier combination: new force_tac (and
  5490 derivatives Force_tac, force) combines rewriting and classical
  5491 reasoning (and whatever other tools) similarly to auto_tac, but is
  5492 aimed to solve the given subgoal completely.
  5493 
  5494 
  5495 *** General ***
  5496 
  5497 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5498 and `goalw': the theory is no longer needed as an explicit argument -
  5499 the current theory context is used; assumptions are no longer returned
  5500 at the ML-level unless one of them starts with ==> or !!; it is
  5501 recommended to convert to these new commands using isatool fixgoal
  5502 (backup your sources first!);
  5503 
  5504 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5505 the current theory context, and 'theory' to lookup stored theories;
  5506 
  5507 * new theory section 'locale' for declaring constants, assumptions and
  5508 definitions that have local scope;
  5509 
  5510 * new theory section 'nonterminals' for purely syntactic types;
  5511 
  5512 * new theory section 'setup' for generic ML setup functions
  5513 (e.g. package initialization);
  5514 
  5515 * the distribution now includes Isabelle icons: see
  5516 lib/logo/isabelle-{small,tiny}.xpm;
  5517 
  5518 * isatool install - install binaries with absolute references to
  5519 ISABELLE_HOME/bin;
  5520 
  5521 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5522 
  5523 * print mode 'emacs' reserved for Isamode;
  5524 
  5525 * support multiple print (ast) translations per constant name;
  5526 
  5527 * theorems involving oracles are now printed with a suffixed [!];
  5528 
  5529 
  5530 *** HOL ***
  5531 
  5532 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5533 
  5534 * HOL/inductive package reorganized and improved: now supports mutual
  5535 definitions such as
  5536 
  5537   inductive EVEN ODD
  5538     intrs
  5539       null "0 : EVEN"
  5540       oddI "n : EVEN ==> Suc n : ODD"
  5541       evenI "n : ODD ==> Suc n : EVEN"
  5542 
  5543 new theorem list "elims" contains an elimination rule for each of the
  5544 recursive sets; inductive definitions now handle disjunctive premises
  5545 correctly (also ZF);
  5546 
  5547 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5548 "mutual_induct" no longer exists - the induction rule is always
  5549 contained in "induct";
  5550 
  5551 
  5552 * HOL/datatype package re-implemented and greatly improved: now
  5553 supports mutually recursive datatypes such as
  5554 
  5555   datatype
  5556     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5557             | SUM ('a aexp) ('a aexp)
  5558             | DIFF ('a aexp) ('a aexp)
  5559             | NUM 'a
  5560   and
  5561     'a bexp = LESS ('a aexp) ('a aexp)
  5562             | AND ('a bexp) ('a bexp)
  5563             | OR ('a bexp) ('a bexp)
  5564 
  5565 as well as indirectly recursive datatypes such as
  5566 
  5567   datatype
  5568     ('a, 'b) term = Var 'a
  5569                   | App 'b ((('a, 'b) term) list)
  5570 
  5571 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5572 induction on mutually / indirectly recursive datatypes.
  5573 
  5574 Primrec equations are now stored in theory and can be accessed via
  5575 <function_name>.simps.
  5576 
  5577 INCOMPATIBILITIES:
  5578 
  5579   - Theories using datatypes must now have theory Datatype as an
  5580     ancestor.
  5581   - The specific <typename>.induct_tac no longer exists - use the
  5582     generic induct_tac instead.
  5583   - natE has been renamed to nat.exhaust - use exhaust_tac
  5584     instead of res_inst_tac ... natE. Note that the variable
  5585     names in nat.exhaust differ from the names in natE, this
  5586     may cause some "fragile" proofs to fail.
  5587   - The theorems split_<typename>_case and split_<typename>_case_asm
  5588     have been renamed to <typename>.split and <typename>.split_asm.
  5589   - Since default sorts of type variables are now handled correctly,
  5590     some datatype definitions may have to be annotated with explicit
  5591     sort constraints.
  5592   - Primrec definitions no longer require function name and type
  5593     of recursive argument.
  5594 
  5595 Consider using isatool fixdatatype to adapt your theories and proof
  5596 scripts to the new package (backup your sources first!).
  5597 
  5598 
  5599 * HOL/record package: considerably improved implementation; now
  5600 includes concrete syntax for record types, terms, updates; theorems
  5601 for surjective pairing and splitting !!-bound record variables; proof
  5602 support is as follows:
  5603 
  5604   1) standard conversions (selectors or updates applied to record
  5605 constructor terms) are part of the standard simpset;
  5606 
  5607   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5608 made part of standard simpset and claset via addIffs;
  5609 
  5610   3) a tactic for record field splitting (record_split_tac) is part of
  5611 the standard claset (addSWrapper);
  5612 
  5613 To get a better idea about these rules you may retrieve them via
  5614 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5615 the name of your record type.
  5616 
  5617 The split tactic 3) conceptually simplifies by the following rule:
  5618 
  5619   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5620 
  5621 Thus any record variable that is bound by meta-all will automatically
  5622 blow up into some record constructor term, consequently the
  5623 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5624 solve record problems automatically.
  5625 
  5626 
  5627 * reorganized the main HOL image: HOL/Integ and String loaded by
  5628 default; theory Main includes everything;
  5629 
  5630 * automatic simplification of integer sums and comparisons, using cancellation;
  5631 
  5632 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5633 
  5634 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5635 
  5636 * many new identities for unions, intersections, set difference, etc.;
  5637 
  5638 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5639 called split_if, split_split, split_sum_case and split_nat_case (to go
  5640 with add/delsplits);
  5641 
  5642 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5643 (?x::unit) = (); this is made part of the default simpset, which COULD
  5644 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5645 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5646 unit_abs_eta_conv is added in order to counter the effect of
  5647 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5648 %u.f();
  5649 
  5650 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5651 makes more sense);
  5652 
  5653 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5654   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5655   disjointness reasoning but breaking a few old proofs.
  5656 
  5657 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5658 to 'converse' from 'inverse' (for compatibility with ZF and some
  5659 literature);
  5660 
  5661 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5662 the well-founded relation;
  5663 
  5664 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5665     Compl A.  The "Compl" syntax remains available as input syntax for this
  5666     release ONLY.
  5667 
  5668 * HOL/Update: new theory of function updates:
  5669     f(a:=b) == %x. if x=a then b else f x
  5670 may also be iterated as in f(a:=b,c:=d,...);
  5671 
  5672 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5673 
  5674 * HOL/List:
  5675   - new function list_update written xs[i:=v] that updates the i-th
  5676     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5677   - new function `upt' written [i..j(] which generates the list
  5678     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5679     bound write [i..j], which is a shorthand for [i..j+1(].
  5680   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5681 
  5682 * HOL/Arith:
  5683   - removed 'pred' (predecessor) function;
  5684   - generalized some theorems about n-1;
  5685   - many new laws about "div" and "mod";
  5686   - new laws about greatest common divisors (see theory ex/Primes);
  5687 
  5688 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5689 instead of "inverse";
  5690 
  5691 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5692   of the multiset ordering;
  5693 
  5694 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5695   (not included by default);
  5696 
  5697 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5698 
  5699 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5700   programs, i.e. different program variables may have different types.
  5701 
  5702 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5703   [previously, this check worked only if the rewrite rule was unconditional]
  5704   Now rew can involve either definitions or equalities (either == or =).
  5705 
  5706 
  5707 *** ZF ***
  5708 
  5709 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5710   only the theorems proved on ZF.ML;
  5711 
  5712 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5713   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5714   disjointness reasoning but breaking a few old proofs.
  5715 
  5716 * ZF/Update: new theory of function updates
  5717     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5718   may also be iterated as in f(a:=b,c:=d,...);
  5719 
  5720 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5721 
  5722 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5723   [previously, this check worked only if the rewrite rule was unconditional]
  5724   Now rew can involve either definitions or equalities (either == or =).
  5725 
  5726 * case_tac provided for compatibility with HOL
  5727     (like the old excluded_middle_tac, but with subgoals swapped)
  5728 
  5729 
  5730 *** Internal programming interfaces ***
  5731 
  5732 * Pure: several new basic modules made available for general use, see
  5733 also src/Pure/README;
  5734 
  5735 * improved the theory data mechanism to support encapsulation (data
  5736 kind name replaced by private Object.kind, acting as authorization
  5737 key); new type-safe user interface via functor TheoryDataFun; generic
  5738 print_data function becomes basically useless;
  5739 
  5740 * removed global_names compatibility flag -- all theory declarations
  5741 are qualified by default;
  5742 
  5743 * module Pure/Syntax now offers quote / antiquote translation
  5744 functions (useful for Hoare logic etc. with implicit dependencies);
  5745 see HOL/ex/Antiquote for an example use;
  5746 
  5747 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5748 cterm -> thm;
  5749 
  5750 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5751 subgoal;
  5752 
  5753 * Display.print_goals function moved to Locale.print_goals;
  5754 
  5755 * standard print function for goals supports current_goals_markers
  5756 variable for marking begin of proof, end of proof, start of goal; the
  5757 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5758 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5759 for example;
  5760 
  5761 
  5762 
  5763 New in Isabelle98 (January 1998)
  5764 --------------------------------
  5765 
  5766 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5767 
  5768 * changed lexical syntax of terms / types: dots made part of long
  5769 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5770 
  5771 * simpset (and claset) reference variable replaced by functions
  5772 simpset / simpset_ref;
  5773 
  5774 * no longer supports theory aliases (via merge) and non-trivial
  5775 implicit merge of thms' signatures;
  5776 
  5777 * most internal names of constants changed due to qualified names;
  5778 
  5779 * changed Pure/Sequence interface (see Pure/seq.ML);
  5780 
  5781 
  5782 *** General Changes ***
  5783 
  5784 * hierachically structured name spaces (for consts, types, axms, thms
  5785 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5786 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5787 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5788 long_names for fully qualified output names; NOTE: ML programs
  5789 (special tactics, packages etc.) referring to internal names may have
  5790 to be adapted to cope with fully qualified names; in case of severe
  5791 backward campatibility problems try setting 'global_names' at compile
  5792 time to have enrything declared within a flat name space; one may also
  5793 fine tune name declarations in theories via the 'global' and 'local'
  5794 section;
  5795 
  5796 * reimplemented the implicit simpset and claset using the new anytype
  5797 data filed in signatures; references simpset:simpset ref etc. are
  5798 replaced by functions simpset:unit->simpset and
  5799 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5800 to patch your ML files accordingly;
  5801 
  5802 * HTML output now includes theory graph data for display with Java
  5803 applet or isatool browser; data generated automatically via isatool
  5804 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5805 
  5806 * defs may now be conditional; improved rewrite_goals_tac to handle
  5807 conditional equations;
  5808 
  5809 * defs now admits additional type arguments, using TYPE('a) syntax;
  5810 
  5811 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5812 creates a new theory node; implicit merge of thms' signatures is
  5813 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5814 transfer:theory->thm->thm in (rare) cases;
  5815 
  5816 * improved handling of draft signatures / theories; draft thms (and
  5817 ctyps, cterms) are automatically promoted to real ones;
  5818 
  5819 * slightly changed interfaces for oracles: admit many per theory, named
  5820 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5821 
  5822 * print_goals: optional output of const types (set show_consts and
  5823 show_types);
  5824 
  5825 * improved output of warnings (###) and errors (***);
  5826 
  5827 * subgoal_tac displays a warning if the new subgoal has type variables;
  5828 
  5829 * removed old README and Makefiles;
  5830 
  5831 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5832 
  5833 * removed obsolete init_pps and init_database;
  5834 
  5835 * deleted the obsolete tactical STATE, which was declared by
  5836     fun STATE tacfun st = tacfun st st;
  5837 
  5838 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5839 (which abbreviates $HOME);
  5840 
  5841 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5842 use isatool fixseq to adapt your ML programs (this works for fully
  5843 qualified references to the Sequence structure only!);
  5844 
  5845 * use_thy no longer requires writable current directory; it always
  5846 reloads .ML *and* .thy file, if either one is out of date;
  5847 
  5848 
  5849 *** Classical Reasoner ***
  5850 
  5851 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5852 tactics that use classical reasoning to simplify a subgoal without
  5853 splitting it into several subgoals;
  5854 
  5855 * Safe_tac: like safe_tac but uses the default claset;
  5856 
  5857 
  5858 *** Simplifier ***
  5859 
  5860 * added simplification meta rules:
  5861     (asm_)(full_)simplify: simpset -> thm -> thm;
  5862 
  5863 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5864 logics (again);
  5865 
  5866 * added prems argument to simplification procedures;
  5867 
  5868 * HOL, FOL, ZF: added infix function `addsplits':
  5869   instead of `<simpset> setloop (split_tac <thms>)'
  5870   you can simply write `<simpset> addsplits <thms>'
  5871 
  5872 
  5873 *** Syntax ***
  5874 
  5875 * TYPE('a) syntax for type reflection terms;
  5876 
  5877 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5878 
  5879 * pretty printer: changed order of mixfix annotation preference (again!);
  5880 
  5881 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5882 
  5883 
  5884 *** HOL ***
  5885 
  5886 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5887   with `addloop' of the simplifier to faciliate case splitting in premises.
  5888 
  5889 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5890 
  5891 * HOL/Auth: new protocol proofs including some for the Internet
  5892   protocol TLS;
  5893 
  5894 * HOL/Map: new theory of `maps' a la VDM;
  5895 
  5896 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5897 cancelling out common nat summands from =, <, <= (in)equalities, or
  5898 differences; simplification procedures nat_cancel_factor for
  5899 cancelling common factor from =, <, <= (in)equalities over natural
  5900 sums; nat_cancel contains both kinds of procedures, it is installed by
  5901 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5902 
  5903 * HOL/simplifier: terms of the form
  5904   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5905   are rewritten to
  5906   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5907   and those of the form
  5908   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5909   are rewritten to
  5910   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5911 
  5912 * HOL/datatype
  5913   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5914 
  5915   P(t_case f1 ... fn x) =
  5916      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5917         ...
  5918        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5919      )
  5920 
  5921   and a theorem `split_t_case_asm' of the form
  5922 
  5923   P(t_case f1 ... fn x) =
  5924     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5925         ...
  5926        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5927      )
  5928   which can be added to a simpset via `addsplits'. The existing theorems
  5929   expand_list_case and expand_option_case have been renamed to
  5930   split_list_case and split_option_case.
  5931 
  5932 * HOL/Arithmetic:
  5933   - `pred n' is automatically converted to `n-1'.
  5934     Users are strongly encouraged not to use `pred' any longer,
  5935     because it will disappear altogether at some point.
  5936   - Users are strongly encouraged to write "0 < n" rather than
  5937     "n ~= 0". Theorems and proof tools have been modified towards this
  5938     `standard'.
  5939 
  5940 * HOL/Lists:
  5941   the function "set_of_list" has been renamed "set" (and its theorems too);
  5942   the function "nth" now takes its arguments in the reverse order and
  5943   has acquired the infix notation "!" as in "xs!n".
  5944 
  5945 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5946 
  5947 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5948   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5949 
  5950 * HOL/record: extensible records with schematic structural subtyping
  5951 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5952 still lacks various theorems and concrete record syntax;
  5953 
  5954 
  5955 *** HOLCF ***
  5956 
  5957 * removed "axioms" and "generated by" sections;
  5958 
  5959 * replaced "ops" section by extended "consts" section, which is capable of
  5960   handling the continuous function space "->" directly;
  5961 
  5962 * domain package:
  5963   . proves theorems immediately and stores them in the theory,
  5964   . creates hierachical name space,
  5965   . now uses normal mixfix annotations (instead of cinfix...),
  5966   . minor changes to some names and values (for consistency),
  5967   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5968   . separator between mutual domain defs: changed "," to "and",
  5969   . improved handling of sort constraints;  now they have to
  5970     appear on the left-hand side of the equations only;
  5971 
  5972 * fixed LAM <x,y,zs>.b syntax;
  5973 
  5974 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5975 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5976 
  5977 
  5978 *** FOL and ZF ***
  5979 
  5980 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5981   with `addloop' of the simplifier to faciliate case splitting in premises.
  5982 
  5983 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5984 in HOL, they strip ALL and --> from proved theorems;
  5985 
  5986 
  5987 
  5988 New in Isabelle94-8 (May 1997)
  5989 ------------------------------
  5990 
  5991 *** General Changes ***
  5992 
  5993 * new utilities to build / run / maintain Isabelle etc. (in parts
  5994 still somewhat experimental); old Makefiles etc. still functional;
  5995 
  5996 * new 'Isabelle System Manual';
  5997 
  5998 * INSTALL text, together with ./configure and ./build scripts;
  5999 
  6000 * reimplemented type inference for greater efficiency, better error
  6001 messages and clean internal interface;
  6002 
  6003 * prlim command for dealing with lots of subgoals (an easier way of
  6004 setting goals_limit);
  6005 
  6006 
  6007 *** Syntax ***
  6008 
  6009 * supports alternative (named) syntax tables (parser and pretty
  6010 printer); internal interface is provided by add_modesyntax(_i);
  6011 
  6012 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6013 be used in conjunction with the Isabelle symbol font; uses the
  6014 "symbols" syntax table;
  6015 
  6016 * added token_translation interface (may translate name tokens in
  6017 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6018 the current print_mode); IMPORTANT: user print translation functions
  6019 are responsible for marking newly introduced bounds
  6020 (Syntax.mark_boundT);
  6021 
  6022 * token translations for modes "xterm" and "xterm_color" that display
  6023 names in bold, underline etc. or colors (which requires a color
  6024 version of xterm);
  6025 
  6026 * infixes may now be declared with names independent of their syntax;
  6027 
  6028 * added typed_print_translation (like print_translation, but may
  6029 access type of constant);
  6030 
  6031 
  6032 *** Classical Reasoner ***
  6033 
  6034 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6035 some limitations.  Blast_tac...
  6036   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6037   + ignores elimination rules that don't have the correct format
  6038         (the conclusion MUST be a formula variable)
  6039   + ignores types, which can make HOL proofs fail
  6040   + rules must not require higher-order unification, e.g. apply_type in ZF
  6041     [message "Function Var's argument not a bound variable" relates to this]
  6042   + its proof strategy is more general but can actually be slower
  6043 
  6044 * substitution with equality assumptions no longer permutes other
  6045 assumptions;
  6046 
  6047 * minor changes in semantics of addafter (now called addaltern); renamed
  6048 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6049 (and access functions for it);
  6050 
  6051 * improved combination of classical reasoner and simplifier:
  6052   + functions for handling clasimpsets
  6053   + improvement of addss: now the simplifier is called _after_ the
  6054     safe steps.
  6055   + safe variant of addss called addSss: uses safe simplifications
  6056     _during_ the safe steps. It is more complete as it allows multiple
  6057     instantiations of unknowns (e.g. with slow_tac).
  6058 
  6059 *** Simplifier ***
  6060 
  6061 * added interface for simplification procedures (functions that
  6062 produce *proven* rewrite rules on the fly, depending on current
  6063 redex);
  6064 
  6065 * ordering on terms as parameter (used for ordered rewriting);
  6066 
  6067 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6068 
  6069 * the solver is now split into a safe and an unsafe part.
  6070 This should be invisible for the normal user, except that the
  6071 functions setsolver and addsolver have been renamed to setSolver and
  6072 addSolver; added safe_asm_full_simp_tac;
  6073 
  6074 
  6075 *** HOL ***
  6076 
  6077 * a generic induction tactic `induct_tac' which works for all datatypes and
  6078 also for type `nat';
  6079 
  6080 * a generic case distinction tactic `exhaust_tac' which works for all
  6081 datatypes and also for type `nat';
  6082 
  6083 * each datatype comes with a function `size';
  6084 
  6085 * patterns in case expressions allow tuple patterns as arguments to
  6086 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6087 
  6088 * primrec now also works with type nat;
  6089 
  6090 * recdef: a new declaration form, allows general recursive functions to be
  6091 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6092 
  6093 * the constant for negation has been renamed from "not" to "Not" to
  6094 harmonize with FOL, ZF, LK, etc.;
  6095 
  6096 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6097 infinite lists;
  6098 
  6099 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6100 
  6101 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6102 problems in commutative rings, using axiomatic type classes for + and *;
  6103 
  6104 * more examples in HOL/MiniML and HOL/Auth;
  6105 
  6106 * more default rewrite rules for quantifiers, union/intersection;
  6107 
  6108 * a new constant `arbitrary == @x.False';
  6109 
  6110 * HOLCF/IOA replaces old HOL/IOA;
  6111 
  6112 * HOLCF changes: derived all rules and arities
  6113   + axiomatic type classes instead of classes
  6114   + typedef instead of faking type definitions
  6115   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6116   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6117   + eliminated the types void, one, tr
  6118   + use unit lift and bool lift (with translations) instead of one and tr
  6119   + eliminated blift from Lift3.thy (use Def instead of blift)
  6120   all eliminated rules are derived as theorems --> no visible changes ;
  6121 
  6122 
  6123 *** ZF ***
  6124 
  6125 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6126 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6127 as ZF_cs addSIs [equalityI];
  6128 
  6129 
  6130 
  6131 New in Isabelle94-7 (November 96)
  6132 ---------------------------------
  6133 
  6134 * allowing negative levels (as offsets) in prlev and choplev;
  6135 
  6136 * super-linear speedup for large simplifications;
  6137 
  6138 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6139 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6140 FAIL); can suppress it using the command Delsimps (ex_simps @
  6141 all_simps); De Morgan laws are also now included, by default;
  6142 
  6143 * improved printing of ==>  :  ~:
  6144 
  6145 * new object-logic "Sequents" adds linear logic, while replacing LK
  6146 and Modal (thanks to Sara Kalvala);
  6147 
  6148 * HOL/Auth: correctness proofs for authentication protocols;
  6149 
  6150 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6151 examples on HOL/Auth);
  6152 
  6153 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6154 the rewriter and classical reasoner simultaneously;
  6155 
  6156 * function uresult no longer returns theorems in "standard" format;
  6157 regain previous version by: val uresult = standard o uresult;
  6158 
  6159 
  6160 
  6161 New in Isabelle94-6
  6162 -------------------
  6163 
  6164 * oracles -- these establish an interface between Isabelle and trusted
  6165 external reasoners, which may deliver results as theorems;
  6166 
  6167 * proof objects (in particular record all uses of oracles);
  6168 
  6169 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6170 
  6171 * "constdefs" section in theory files;
  6172 
  6173 * "primrec" section (HOL) no longer requires names;
  6174 
  6175 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6176 
  6177 
  6178 
  6179 New in Isabelle94-5
  6180 -------------------
  6181 
  6182 * reduced space requirements;
  6183 
  6184 * automatic HTML generation from theories;
  6185 
  6186 * theory files no longer require "..." (quotes) around most types;
  6187 
  6188 * new examples, including two proofs of the Church-Rosser theorem;
  6189 
  6190 * non-curried (1994) version of HOL is no longer distributed;
  6191 
  6192 
  6193 
  6194 New in Isabelle94-4
  6195 -------------------
  6196 
  6197 * greatly reduced space requirements;
  6198 
  6199 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6200 
  6201 * searchable theorem database (see the section "Retrieving theorems" on
  6202 page 8 of the Reference Manual);
  6203 
  6204 * new examples, including Grabczewski's monumental case study of the
  6205 Axiom of Choice;
  6206 
  6207 * The previous version of HOL renamed to Old_HOL;
  6208 
  6209 * The new version of HOL (previously called CHOL) uses a curried syntax
  6210 for functions.  Application looks like f a b instead of f(a,b);
  6211 
  6212 * Mutually recursive inductive definitions finally work in HOL;
  6213 
  6214 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6215 translates to the operator "split";
  6216 
  6217 
  6218 
  6219 New in Isabelle94-3
  6220 -------------------
  6221 
  6222 * new infix operator, addss, allowing the classical reasoner to
  6223 perform simplification at each step of its search.  Example:
  6224         fast_tac (cs addss ss)
  6225 
  6226 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6227 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6228 look like (a,b) instead of <a,b>;
  6229 
  6230 * PLEASE NOTE: CHOL will eventually replace HOL!
  6231 
  6232 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6233 It translates to the operator "split".  A new theory of integers is available;
  6234 
  6235 * In ZF, integer numerals now denote two's-complement binary integers.
  6236 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6237 
  6238 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6239 of the Axiom of Choice;
  6240 
  6241 
  6242 
  6243 New in Isabelle94-2
  6244 -------------------
  6245 
  6246 * Significantly faster resolution;
  6247 
  6248 * the different sections in a .thy file can now be mixed and repeated
  6249 freely;
  6250 
  6251 * Database of theorems for FOL, HOL and ZF.  New
  6252 commands including qed, qed_goal and bind_thm store theorems in the database.
  6253 
  6254 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6255 a given theory (thms_of), or find out what theory a theorem was proved in
  6256 (theory_of_thm);
  6257 
  6258 * Bugs fixed in the inductive definition and datatype packages;
  6259 
  6260 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6261 and HOL_dup_cs obsolete;
  6262 
  6263 * Syntactic ambiguities cause