NEWS
author haftmann
Sat Jun 13 10:01:00 2009 +0200 (2009-06-13)
changeset 31624 4b792a97a1fb
parent 31481 60ae1588f232
child 31626 fe35b72b9ef0
permissions -rw-r--r--
quickcheck using generic code generator
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** Pure ***
     8 
     9 * On instantiation of classes, remaining undefined class parameters are
    10 formally declared.  INCOMPATIBILITY.
    11 
    12 
    13 *** HOL ***
    14 
    15 * Class semiring_div requires superclass no_zero_divisors and proof of div_mult_mult1;
    16 theorems div_mult_mult1, div_mult_mult2, div_mult_mult1_if, div_mult_mult1 and
    17 div_mult_mult2 have been generalized to class semiring_div, subsuming former
    18 theorems zdiv_zmult_zmult1, zdiv_zmult_zmult1_if, zdiv_zmult_zmult1 and zdiv_zmult_zmult2.
    19 div_mult_mult1 is now [simp] by default.  INCOMPATIBILITY.
    20 
    21 * Power operations on relations and functions are now one dedicate constant compow with
    22 infix syntax "^^".  Power operations on multiplicative monoids retains syntax "^"
    23 and is now defined generic in class power.  INCOMPATIBILITY.
    24 
    25 * ML antiquotation @{code_datatype} inserts definition of a datatype generated
    26 by the code generator; see Predicate.thy for an example.
    27 
    28 * New method "linarith" invokes existing linear arithmetic decision procedure only.
    29 
    30 * Implementation of quickcheck using generic code generator; default generators
    31 are provided for all suitable HOL types, records and datatypes.
    32 
    33 
    34 *** ML ***
    35 
    36 * Eliminated old Attrib.add_attributes, Method.add_methods and related
    37 cominators for "args".  INCOMPATIBILITY, need to use simplified
    38 Attrib/Method.setup introduced in Isabelle2009.
    39 
    40 
    41 *** System ***
    42 
    43 * Discontinued support for Poly/ML 4.x versions.
    44 
    45 * Removed "compress" option from isabelle-process and isabelle usedir;
    46 this is always enabled.
    47 
    48 
    49 
    50 New in Isabelle2009 (April 2009)
    51 --------------------------------
    52 
    53 *** General ***
    54 
    55 * Simplified main Isabelle executables, with less surprises on
    56 case-insensitive file-systems (such as Mac OS).
    57 
    58   - The main Isabelle tool wrapper is now called "isabelle" instead of
    59     "isatool."
    60 
    61   - The former "isabelle" alias for "isabelle-process" has been
    62     removed (should rarely occur to regular users).
    63 
    64   - The former "isabelle-interface" and its alias "Isabelle" have been
    65     removed (interfaces are now regular Isabelle tools).
    66 
    67 Within scripts and make files, the Isabelle environment variables
    68 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    69 respectively.  (The latter are still available as legacy feature.)
    70 
    71 The old isabelle-interface wrapper could react in confusing ways if
    72 the interface was uninstalled or changed otherwise.  Individual
    73 interface tool configuration is now more explicit, see also the
    74 Isabelle system manual.  In particular, Proof General is now available
    75 via "isabelle emacs".
    76 
    77 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    78 purge installed copies of Isabelle executables and re-run "isabelle
    79 install -p ...", or use symlinks.
    80 
    81 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    82 old ~/isabelle, which was slightly non-standard and apt to cause
    83 surprises on case-insensitive file-systems (such as Mac OS).
    84 
    85 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    86 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    87 care is required when using older releases of Isabelle.  Note that
    88 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    89 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
    90 
    91 * Proofs of fully specified statements are run in parallel on
    92 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
    93 a regular 4-core machine, if the initial heap space is made reasonably
    94 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
    95 
    96 * The main reference manuals ("isar-ref", "implementation", and
    97 "system") have been updated and extended.  Formally checked references
    98 as hyperlinks are now available uniformly.
    99 
   100 
   101 *** Pure ***
   102 
   103 * Complete re-implementation of locales.  INCOMPATIBILITY in several
   104 respects.  The most important changes are listed below.  See the
   105 Tutorial on Locales ("locales" manual) for details.
   106 
   107 - In locale expressions, instantiation replaces renaming.  Parameters
   108 must be declared in a for clause.  To aid compatibility with previous
   109 parameter inheritance, in locale declarations, parameters that are not
   110 'touched' (instantiation position "_" or omitted) are implicitly added
   111 with their syntax at the beginning of the for clause.
   112 
   113 - Syntax from abbreviations and definitions in locales is available in
   114 locale expressions and context elements.  The latter is particularly
   115 useful in locale declarations.
   116 
   117 - More flexible mechanisms to qualify names generated by locale
   118 expressions.  Qualifiers (prefixes) may be specified in locale
   119 expressions, and can be marked as mandatory (syntax: "name!:") or
   120 optional (syntax "name?:").  The default depends for plain "name:"
   121 depends on the situation where a locale expression is used: in
   122 commands 'locale' and 'sublocale' prefixes are optional, in
   123 'interpretation' and 'interpret' prefixes are mandatory.  The old
   124 implicit qualifiers derived from the parameter names of a locale are
   125 no longer generated.
   126 
   127 - Command "sublocale l < e" replaces "interpretation l < e".  The
   128 instantiation clause in "interpretation" and "interpret" (square
   129 brackets) is no longer available.  Use locale expressions.
   130 
   131 - When converting proof scripts, mandatory qualifiers in
   132 'interpretation' and 'interpret' should be retained by default, even
   133 if this is an INCOMPATIBILITY compared to former behavior.  In the
   134 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   135 in locale expressions range over a single locale instance only.
   136 
   137 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   138 In existing theorem specifications replace the includes element by the
   139 respective context elements of the included locale, omitting those
   140 that are already present in the theorem specification.  Multiple
   141 assume elements of a locale should be replaced by a single one
   142 involving the locale predicate.  In the proof body, declarations (most
   143 notably theorems) may be regained by interpreting the respective
   144 locales in the proof context as required (command "interpret").
   145 
   146 If using "includes" in replacement of a target solely because the
   147 parameter types in the theorem are not as general as in the target,
   148 consider declaring a new locale with additional type constraints on
   149 the parameters (context element "constrains").
   150 
   151 - Discontinued "locale (open)".  INCOMPATIBILITY.
   152 
   153 - Locale interpretation commands no longer attempt to simplify goal.
   154 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   155 methods intro_locales and unfold_locales to clarify.
   156 
   157 - Locale interpretation commands no longer accept interpretation
   158 attributes.  INCOMPATIBILITY.
   159 
   160 * Class declaration: so-called "base sort" must not be given in import
   161 list any longer, but is inferred from the specification.  Particularly
   162 in HOL, write
   163 
   164     class foo = ...
   165 
   166 instead of
   167 
   168     class foo = type + ...
   169 
   170 * Class target: global versions of theorems stemming do not carry a
   171 parameter prefix any longer.  INCOMPATIBILITY.
   172 
   173 * Class 'instance' command no longer accepts attached definitions.
   174 INCOMPATIBILITY, use proper 'instantiation' target instead.
   175 
   176 * Recovered hiding of consts, which was accidentally broken in
   177 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   178 makes c inaccessible; consider using ``hide (open) const c'' instead.
   179 
   180 * Slightly more coherent Pure syntax, with updated documentation in
   181 isar-ref manual.  Removed locales meta_term_syntax and
   182 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   183 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   184 directly in regular applications.
   185 
   186 * There is a new syntactic category "float_const" for signed decimal
   187 fractions (e.g. 123.45 or -123.45).
   188 
   189 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   190 interface with 'setup' command instead.
   191 
   192 * Command 'local_setup' is similar to 'setup', but operates on a local
   193 theory context.
   194 
   195 * The 'axiomatization' command now only works within a global theory
   196 context.  INCOMPATIBILITY.
   197 
   198 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   199 hypotheses.  Sorts required in the course of reasoning need to be
   200 covered by the constraints in the initial statement, completed by the
   201 type instance information of the background theory.  Non-trivial sort
   202 hypotheses, which rarely occur in practice, may be specified via
   203 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   204 
   205   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   206 
   207 The result contains an implicit sort hypotheses as before --
   208 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   209 normalization.
   210 
   211 * Generalized Isar history, with support for linear undo, direct state
   212 addressing etc.
   213 
   214 * Changed defaults for unify configuration options:
   215 
   216   unify_trace_bound = 50 (formerly 25)
   217   unify_search_bound = 60 (formerly 30)
   218 
   219 * Different bookkeeping for code equations (INCOMPATIBILITY):
   220 
   221   a) On theory merge, the last set of code equations for a particular
   222      constant is taken (in accordance with the policy applied by other
   223      parts of the code generator framework).
   224 
   225   b) Code equations stemming from explicit declarations (e.g. code
   226      attribute) gain priority over default code equations stemming
   227      from definition, primrec, fun etc.
   228 
   229 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   230 
   231 * Unified theorem tables for both code generators.  Thus [code
   232 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   233 
   234 * Command 'find_consts' searches for constants based on type and name
   235 patterns, e.g.
   236 
   237     find_consts "_ => bool"
   238 
   239 By default, matching is against subtypes, but it may be restricted to
   240 the whole type.  Searching by name is possible.  Multiple queries are
   241 conjunctive and queries may be negated by prefixing them with a
   242 hyphen:
   243 
   244     find_consts strict: "_ => bool" name: "Int" -"int => int"
   245 
   246 * New 'find_theorems' criterion "solves" matches theorems that
   247 directly solve the current goal (modulo higher-order unification).
   248 
   249 * Auto solve feature for main theorem statements: whenever a new goal
   250 is stated, "find_theorems solves" is called; any theorems that could
   251 solve the lemma directly are listed as part of the goal state.
   252 Cf. associated options in Proof General Isabelle settings menu,
   253 enabled by default, with reasonable timeout for pathological cases of
   254 higher-order unification.
   255 
   256 
   257 *** Document preparation ***
   258 
   259 * Antiquotation @{lemma} now imitates a regular terminal proof,
   260 demanding keyword 'by' and supporting the full method expression
   261 syntax just like the Isar command 'by'.
   262 
   263 
   264 *** HOL ***
   265 
   266 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   267 points Main and Complex_Main remain as before.
   268 
   269 * Logic image HOL-Plain provides a minimal HOL with the most important
   270 tools available (inductive, datatype, primrec, ...).  This facilitates
   271 experimentation and tool development.  Note that user applications
   272 (and library theories) should never refer to anything below theory
   273 Main, as before.
   274 
   275 * Logic image HOL-Main stops at theory Main, and thus facilitates
   276 experimentation due to shorter build times.
   277 
   278 * Logic image HOL-NSA contains theories of nonstandard analysis which
   279 were previously part of former HOL-Complex.  Entry point Hyperreal
   280 remains valid, but theories formerly using Complex_Main should now use
   281 new entry point Hypercomplex.
   282 
   283 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   284 Posix processes.  Avoids potentially expensive forking of the ML
   285 process.  New thread-based implementation also works on non-Unix
   286 platforms (Cygwin).  Provers are no longer hardwired, but defined
   287 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   288 commands are covered in the isar-ref manual.
   289 
   290 * Wrapper scripts for remote SystemOnTPTP service allows to use
   291 sledgehammer without local ATP installation (Vampire etc.). Other
   292 provers may be included via suitable ML wrappers, see also
   293 src/HOL/ATP_Linkup.thy.
   294 
   295 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   296 menu.
   297 
   298 * The metis method no longer fails because the theorem is too trivial
   299 (contains the empty clause).
   300 
   301 * The metis method now fails in the usual manner, rather than raising
   302 an exception, if it determines that it cannot prove the theorem.
   303 
   304 * Method "coherent" implements a prover for coherent logic (see also
   305 src/Tools/coherent.ML).
   306 
   307 * Constants "undefined" and "default" replace "arbitrary".  Usually
   308 "undefined" is the right choice to replace "arbitrary", though
   309 logically there is no difference.  INCOMPATIBILITY.
   310 
   311 * Command "value" now integrates different evaluation mechanisms.  The
   312 result of the first successful evaluation mechanism is printed.  In
   313 square brackets a particular named evaluation mechanisms may be
   314 specified (currently, [SML], [code] or [nbe]).  See further
   315 src/HOL/ex/Eval_Examples.thy.
   316 
   317 * Normalization by evaluation now allows non-leftlinear equations.
   318 Declare with attribute [code nbe].
   319 
   320 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   321 as the structured Isar versions "cases" and "induct", cf. the
   322 corresponding "cases" and "induct" attributes.  Mutual induction rules
   323 are now presented as a list of individual projections
   324 (e.g. foo_bar.inducts for types foo and bar); the old format with
   325 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   326 rare situations a different rule is selected --- notably nested tuple
   327 elimination instead of former prod.exhaust: use explicit (case_tac t
   328 rule: prod.exhaust) here.
   329 
   330 * Attributes "cases", "induct", "coinduct" support "del" option.
   331 
   332 * Removed fact "case_split_thm", which duplicates "case_split".
   333 
   334 * The option datatype has been moved to a new theory Option.  Renamed
   335 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   336 
   337 * New predicate "strict_mono" classifies strict functions on partial
   338 orders.  With strict functions on linear orders, reasoning about
   339 (in)equalities is facilitated by theorems "strict_mono_eq",
   340 "strict_mono_less_eq" and "strict_mono_less".
   341 
   342 * Some set operations are now proper qualified constants with
   343 authentic syntax.  INCOMPATIBILITY:
   344 
   345     op Int ~>   Set.Int
   346     op Un ~>    Set.Un
   347     INTER ~>    Set.INTER
   348     UNION ~>    Set.UNION
   349     Inter ~>    Set.Inter
   350     Union ~>    Set.Union
   351     {} ~>       Set.empty
   352     UNIV ~>     Set.UNIV
   353 
   354 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   355 theory Set.
   356 
   357 * Auxiliary class "itself" has disappeared -- classes without any
   358 parameter are treated as expected by the 'class' command.
   359 
   360 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   361 
   362 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   363 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   364 
   365 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   366 method "approximation".  It proves formulas on real values by using
   367 interval arithmetic.  In the formulas are also the transcendental
   368 functions sin, cos, tan, atan, ln, exp and the constant pi are
   369 allowed. For examples see
   370 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   371 
   372 * Theory "Reflection" now resides in HOL/Library.
   373 
   374 * Entry point to Word library now simply named "Word".
   375 INCOMPATIBILITY.
   376 
   377 * Made source layout more coherent with logical distribution
   378 structure:
   379 
   380     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   381     src/HOL/Library/Code_Message.thy ~> src/HOL/
   382     src/HOL/Library/GCD.thy ~> src/HOL/
   383     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   384     src/HOL/Library/Parity.thy ~> src/HOL/
   385     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   386     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   387     src/HOL/Real/Lubs.thy ~> src/HOL/
   388     src/HOL/Real/PReal.thy ~> src/HOL/
   389     src/HOL/Real/Rational.thy ~> src/HOL/
   390     src/HOL/Real/RComplete.thy ~> src/HOL/
   391     src/HOL/Real/RealDef.thy ~> src/HOL/
   392     src/HOL/Real/RealPow.thy ~> src/HOL/
   393     src/HOL/Real/Real.thy ~> src/HOL/
   394     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   395     src/HOL/Complex/Complex.thy ~> src/HOL/
   396     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   397     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   398     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   399     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   400     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   401     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   402     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   403     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   404     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   405     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   406     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   407     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   408     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   409     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   410     src/HOL/Real/Float ~> src/HOL/Library/
   411     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   412     src/HOL/Real/RealVector.thy ~> src/HOL/
   413 
   414     src/HOL/arith_data.ML ~> src/HOL/Tools
   415     src/HOL/hologic.ML ~> src/HOL/Tools
   416     src/HOL/simpdata.ML ~> src/HOL/Tools
   417     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   418     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   419     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   420     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   421     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   422     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   423     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   424 
   425     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   426     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   427     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   428     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   429     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   430     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   431 
   432 * If methods "eval" and "evaluation" encounter a structured proof
   433 state with !!/==>, only the conclusion is evaluated to True (if
   434 possible), avoiding strange error messages.
   435 
   436 * Method "sizechange" automates termination proofs using (a
   437 modification of) the size-change principle.  Requires SAT solver.  See
   438 src/HOL/ex/Termination.thy for examples.
   439 
   440 * Simplifier: simproc for let expressions now unfolds if bound
   441 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   442 
   443 * Method "arith": Linear arithmetic now ignores all inequalities when
   444 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   445 
   446 * New attribute "arith" for facts that should always be used
   447 automatically by arithmetic. It is intended to be used locally in
   448 proofs, e.g.
   449 
   450   assumes [arith]: "x > 0"
   451 
   452 Global usage is discouraged because of possible performance impact.
   453 
   454 * New classes "top" and "bot" with corresponding operations "top" and
   455 "bot" in theory Orderings; instantiation of class "complete_lattice"
   456 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   457 
   458 * Changed definition lemma "less_fun_def" in order to provide an
   459 instance for preorders on functions; use lemma "less_le" instead.
   460 INCOMPATIBILITY.
   461 
   462 * Theory Orderings: class "wellorder" moved here, with explicit
   463 induction rule "less_induct" as assumption.  For instantiation of
   464 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   465 INCOMPATIBILITY.
   466 
   467 * Theory Orderings: added class "preorder" as superclass of "order".
   468 INCOMPATIBILITY: Instantiation proofs for order, linorder
   469 etc. slightly changed.  Some theorems named order_class.* now named
   470 preorder_class.*.
   471 
   472 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   473 "diag" to "Id_on".
   474 
   475 * Theory Finite_Set: added a new fold combinator of type
   476 
   477   ('a => 'b => 'b) => 'b => 'a set => 'b
   478 
   479 Occasionally this is more convenient than the old fold combinator
   480 which is now defined in terms of the new one and renamed to
   481 fold_image.
   482 
   483 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   484 and "ring_simps" have been replaced by "algebra_simps" (which can be
   485 extended with further lemmas!).  At the moment both still exist but
   486 the former will disappear at some point.
   487 
   488 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   489 class recpower.  Type-specific simp rules for various recpower types
   490 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   491 
   492 rat_power_0    -> power_0
   493 rat_power_Suc  -> power_Suc
   494 realpow_0      -> power_0
   495 realpow_Suc    -> power_Suc
   496 complexpow_0   -> power_0
   497 complexpow_Suc -> power_Suc
   498 power_poly_0   -> power_0
   499 power_poly_Suc -> power_Suc
   500 
   501 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   502 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   503 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   504 of lemmas from Divides has been generalized from nat to class
   505 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   506 renames resulting from duplicate elimination:
   507 
   508     dvd_def_mod ~>          dvd_eq_mod_eq_0
   509     zero_dvd_iff ~>         dvd_0_left_iff
   510     dvd_0 ~>                dvd_0_right
   511     DIVISION_BY_ZERO_DIV ~> div_by_0
   512     DIVISION_BY_ZERO_MOD ~> mod_by_0
   513     mult_div ~>             div_mult_self2_is_id
   514     mult_mod ~>             mod_mult_self2_is_0
   515 
   516 * Theory IntDiv: removed many lemmas that are instances of class-based
   517 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   518 rename old lemmas as follows:
   519 
   520 dvd_diff               -> nat_dvd_diff
   521 dvd_zminus_iff         -> dvd_minus_iff
   522 mod_add1_eq            -> mod_add_eq
   523 mod_mult1_eq           -> mod_mult_right_eq
   524 mod_mult1_eq'          -> mod_mult_left_eq
   525 mod_mult_distrib_mod   -> mod_mult_eq
   526 nat_mod_add_left_eq    -> mod_add_left_eq
   527 nat_mod_add_right_eq   -> mod_add_right_eq
   528 nat_mod_div_trivial    -> mod_div_trivial
   529 nat_mod_mod_trivial    -> mod_mod_trivial
   530 zdiv_zadd_self1        -> div_add_self1
   531 zdiv_zadd_self2        -> div_add_self2
   532 zdiv_zmult_self1       -> div_mult_self2_is_id
   533 zdiv_zmult_self2       -> div_mult_self1_is_id
   534 zdvd_triv_left         -> dvd_triv_left
   535 zdvd_triv_right        -> dvd_triv_right
   536 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   537 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   538 zmod_zadd_left_eq      -> mod_add_left_eq
   539 zmod_zadd_right_eq     -> mod_add_right_eq
   540 zmod_zadd_self1        -> mod_add_self1
   541 zmod_zadd_self2        -> mod_add_self2
   542 zmod_zadd1_eq          -> mod_add_eq
   543 zmod_zdiff1_eq         -> mod_diff_eq
   544 zmod_zdvd_zmod         -> mod_mod_cancel
   545 zmod_zmod_cancel       -> mod_mod_cancel
   546 zmod_zmult_self1       -> mod_mult_self2_is_0
   547 zmod_zmult_self2       -> mod_mult_self1_is_0
   548 zmod_1                 -> mod_by_1
   549 zdiv_1                 -> div_by_1
   550 zdvd_abs1              -> abs_dvd_iff
   551 zdvd_abs2              -> dvd_abs_iff
   552 zdvd_refl              -> dvd_refl
   553 zdvd_trans             -> dvd_trans
   554 zdvd_zadd              -> dvd_add
   555 zdvd_zdiff             -> dvd_diff
   556 zdvd_zminus_iff        -> dvd_minus_iff
   557 zdvd_zminus2_iff       -> minus_dvd_iff
   558 zdvd_zmultD            -> dvd_mult_right
   559 zdvd_zmultD2           -> dvd_mult_left
   560 zdvd_zmult_mono        -> mult_dvd_mono
   561 zdvd_0_right           -> dvd_0_right
   562 zdvd_0_left            -> dvd_0_left_iff
   563 zdvd_1_left            -> one_dvd
   564 zminus_dvd_iff         -> minus_dvd_iff
   565 
   566 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   567 
   568 * The real numbers offer decimal input syntax: 12.34 is translated
   569 into 1234/10^2. This translation is not reversed upon output.
   570 
   571 * Theory Library/Polynomial defines an abstract type 'a poly of
   572 univariate polynomials with coefficients of type 'a.  In addition to
   573 the standard ring operations, it also supports div and mod.  Code
   574 generation is also supported, using list-style constructors.
   575 
   576 * Theory Library/Inner_Product defines a class of real_inner for real
   577 inner product spaces, with an overloaded operation inner :: 'a => 'a
   578 => real.  Class real_inner is a subclass of real_normed_vector from
   579 theory RealVector.
   580 
   581 * Theory Library/Product_Vector provides instances for the product
   582 type 'a * 'b of several classes from RealVector and Inner_Product.
   583 Definitions of addition, subtraction, scalar multiplication, norms,
   584 and inner products are included.
   585 
   586 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   587 addition to the field operations, numerals and case syntax are also
   588 supported.
   589 
   590 * Theory Library/Diagonalize provides constructive version of Cantor's
   591 first diagonalization argument.
   592 
   593 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   594 zlcm (for int); carried together from various gcd/lcm developements in
   595 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   596 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   597 may recover tupled syntax as follows:
   598 
   599     hide (open) const gcd
   600     abbreviation gcd where
   601       "gcd == (%(a, b). GCD.gcd a b)"
   602     notation (output)
   603       GCD.gcd ("gcd '(_, _')")
   604 
   605 The same works for lcm, zgcd, zlcm.
   606 
   607 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   608 instantiations for algebraic structures.  Removed some duplicate
   609 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   610 
   611 * ML antiquotation @{code} takes a constant as argument and generates
   612 corresponding code in background and inserts name of the corresponding
   613 resulting ML value/function/datatype constructor binding in place.
   614 All occurrences of @{code} with a single ML block are generated
   615 simultaneously.  Provides a generic and safe interface for
   616 instrumentalizing code generation.  See
   617 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   618 In future you ought to refrain from ad-hoc compiling generated SML
   619 code on the ML toplevel.  Note that (for technical reasons) @{code}
   620 cannot refer to constants for which user-defined serializations are
   621 set.  Refer to the corresponding ML counterpart directly in that
   622 cases.
   623 
   624 * Command 'rep_datatype': instead of theorem names the command now
   625 takes a list of terms denoting the constructors of the type to be
   626 represented as datatype.  The characteristic theorems have to be
   627 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   628 have disappeared in favour of existing ones:
   629 
   630     unit_induct                 ~> unit.induct
   631     prod_induct                 ~> prod.induct
   632     sum_induct                  ~> sum.induct
   633     Suc_Suc_eq                  ~> nat.inject
   634     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   635 
   636 
   637 *** HOL-Algebra ***
   638 
   639 * New locales for orders and lattices where the equivalence relation
   640 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   641 locales use a record structure with field eq for the equivalence.
   642 
   643 * New theory of factorial domains.
   644 
   645 * Units_l_inv and Units_r_inv are now simp rules by default.
   646 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   647 and/or r_inv will now also require deletion of these lemmas.
   648 
   649 * Renamed the following theorems, INCOMPATIBILITY:
   650 
   651 UpperD ~> Upper_memD
   652 LowerD ~> Lower_memD
   653 least_carrier ~> least_closed
   654 greatest_carrier ~> greatest_closed
   655 greatest_Lower_above ~> greatest_Lower_below
   656 one_zero ~> carrier_one_zero
   657 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   658 
   659 
   660 *** HOL-Nominal ***
   661 
   662 * Nominal datatypes can now contain type-variables.
   663 
   664 * Commands 'nominal_inductive' and 'equivariance' work with local
   665 theory targets.
   666 
   667 * Nominal primrec can now works with local theory targets and its
   668 specification syntax now conforms to the general format as seen in
   669 'inductive' etc.
   670 
   671 * Method "perm_simp" honours the standard simplifier attributes
   672 (no_asm), (no_asm_use) etc.
   673 
   674 * The new predicate #* is defined like freshness, except that on the
   675 left hand side can be a set or list of atoms.
   676 
   677 * Experimental command 'nominal_inductive2' derives strong induction
   678 principles for inductive definitions.  In contrast to
   679 'nominal_inductive', which can only deal with a fixed number of
   680 binders, it can deal with arbitrary expressions standing for sets of
   681 atoms to be avoided.  The only inductive definition we have at the
   682 moment that needs this generalisation is the typing rule for Lets in
   683 the algorithm W:
   684 
   685  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   686  -----------------------------------------------------------------
   687          Gamma |- Let x be t1 in t2 : T2
   688 
   689 In this rule one wants to avoid all the binders that are introduced by
   690 "close Gamma T1".  We are looking for other examples where this
   691 feature might be useful.  Please let us know.
   692 
   693 
   694 *** HOLCF ***
   695 
   696 * Reimplemented the simplification procedure for proving continuity
   697 subgoals.  The new simproc is extensible; users can declare additional
   698 continuity introduction rules with the attribute [cont2cont].
   699 
   700 * The continuity simproc now uses a different introduction rule for
   701 solving continuity subgoals on terms with lambda abstractions.  In
   702 some rare cases the new simproc may fail to solve subgoals that the
   703 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   704 Potential INCOMPATIBILITY.
   705 
   706 * Command 'fixrec': specification syntax now conforms to the general
   707 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   708 examples.  INCOMPATIBILITY.
   709 
   710 
   711 *** ZF ***
   712 
   713 * Proof of Zorn's Lemma for partial orders.
   714 
   715 
   716 *** ML ***
   717 
   718 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   719 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   720 depends on multithreading, so timouts will not work before Poly/ML
   721 5.2.1!
   722 
   723 * High-level support for concurrent ML programming, see
   724 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   725 particularly convenient to organize independent functional
   726 computations.  The concept of "synchronized variables" provides a
   727 higher-order interface for components with shared state, avoiding the
   728 delicate details of mutexes and condition variables.  (Requires
   729 Poly/ML 5.2.1 or later.)
   730 
   731 * ML bindings produced via Isar commands are stored within the Isar
   732 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   733 become thread-safe and work with undo as expected (concerning
   734 top-level bindings, not side-effects on global references).
   735 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   736 compiler at runtime; really global bindings need to be given outside a
   737 theory.  (Requires Poly/ML 5.2 or later.)
   738 
   739 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   740 context.  Top-level ML bindings are stored within the proof context in
   741 a purely sequential fashion, disregarding the nested proof structure.
   742 ML bindings introduced by 'ML_prf' are discarded at the end of the
   743 proof.  (Requires Poly/ML 5.2 or later.)
   744 
   745 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   746 and Method.setup, as well as Isar commands 'attribute_setup' and
   747 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   748 existing code accordingly, or use plain 'setup' together with old
   749 Method.add_method.
   750 
   751 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   752 to 'a -> thm, while results are always tagged with an authentic oracle
   753 name.  The Isar command 'oracle' is now polymorphic, no argument type
   754 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   755 accordingly.  Note that extra performance may be gained by producing
   756 the cterm carefully, avoiding slow Thm.cterm_of.
   757 
   758 * Simplified interface for defining document antiquotations via
   759 ThyOutput.antiquotation, ThyOutput.output, and optionally
   760 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   761 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   762 examples.
   763 
   764 * More systematic treatment of long names, abstract name bindings, and
   765 name space operations.  Basic operations on qualified names have been
   766 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   767 Long_Name.append.  Old type bstring has been mostly replaced by
   768 abstract type binding (see structure Binding), which supports precise
   769 qualification by packages and local theory targets, as well as proper
   770 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   771 bstring values into Binding.name, or better pass through abstract
   772 bindings everywhere.  See further src/Pure/General/long_name.ML,
   773 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   774 
   775 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   776 LocalTheory.note etc.) now refer to the *full* internal name, not the
   777 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   778 
   779 * Disposed old type and term read functions (Sign.read_def_typ,
   780 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   781 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   782 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   783 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   784 resort for legacy applications.
   785 
   786 * Disposed old declarations, tactics, tactic combinators that refer to
   787 the simpset or claset of an implicit theory (such as Addsimps,
   788 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   789 embedded ML text, or local_simpset_of with a proper context passed as
   790 explicit runtime argument.
   791 
   792 * Rules and tactics that read instantiations (read_instantiate,
   793 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   794 context, which is required for parsing and type-checking.  Moreover,
   795 the variables are specified as plain indexnames, not string encodings
   796 thereof.  INCOMPATIBILITY.
   797 
   798 * Generic Toplevel.add_hook interface allows to analyze the result of
   799 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   800 for theorem dependency output of transactions resulting in a new
   801 theory state.
   802 
   803 * ML antiquotations: block-structured compilation context indicated by
   804 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   805 
   806   @{binding name}                         - basic name binding
   807   @{let ?pat = term}                      - term abbreviation (HO matching)
   808   @{note name = fact}                     - fact abbreviation
   809   @{thm fact}                             - singleton fact (with attributes)
   810   @{thms fact}                            - general fact (with attributes)
   811   @{lemma prop by method}                 - singleton goal
   812   @{lemma prop by meth1 meth2}            - singleton goal
   813   @{lemma prop1 ... propN by method}      - general goal
   814   @{lemma prop1 ... propN by meth1 meth2} - general goal
   815   @{lemma (open) ...}                     - open derivation
   816 
   817 
   818 *** System ***
   819 
   820 * The Isabelle "emacs" tool provides a specific interface to invoke
   821 Proof General / Emacs, with more explicit failure if that is not
   822 installed (the old isabelle-interface script silently falls back on
   823 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   824 installation location of the Proof General distribution.
   825 
   826 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   827 the Isabelle process into a JVM/Scala application.  See
   828 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   829 process wrapper has been discontinued.)
   830 
   831 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   832 
   833 * Various status messages (with exact source position information) are
   834 emitted, if proper markup print mode is enabled.  This allows
   835 user-interface components to provide detailed feedback on internal
   836 prover operations.
   837 
   838 
   839 
   840 New in Isabelle2008 (June 2008)
   841 -------------------------------
   842 
   843 *** General ***
   844 
   845 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   846 and updated, with formally checked references as hyperlinks.
   847 
   848 * Theory loader: use_thy (and similar operations) no longer set the
   849 implicit ML context, which was occasionally hard to predict and in
   850 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   851 provides a proper context already.
   852 
   853 * Theory loader: old-style ML proof scripts being *attached* to a thy
   854 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   855 'use' within a theory file will do the job.
   856 
   857 * Name space merge now observes canonical order, i.e. the second space
   858 is inserted into the first one, while existing entries in the first
   859 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   860 swap theory imports.
   861 
   862 * Syntax: symbol \<chi> is now considered a letter.  Potential
   863 INCOMPATIBILITY in identifier syntax etc.
   864 
   865 * Outer syntax: string tokens no longer admit escaped white space,
   866 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   867 white space without escapes.
   868 
   869 * Outer syntax: string tokens may contain arbitrary character codes
   870 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   871 "foo_bar".
   872 
   873 
   874 *** Pure ***
   875 
   876 * Context-dependent token translations.  Default setup reverts locally
   877 fixed variables, and adds hilite markup for undeclared frees.
   878 
   879 * Unused theorems can be found using the new command 'unused_thms'.
   880 There are three ways of invoking it:
   881 
   882 (1) unused_thms
   883      Only finds unused theorems in the current theory.
   884 
   885 (2) unused_thms thy_1 ... thy_n -
   886      Finds unused theorems in the current theory and all of its ancestors,
   887      excluding the theories thy_1 ... thy_n and all of their ancestors.
   888 
   889 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   890      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   891      their ancestors, excluding the theories thy_1 ... thy_n and all of
   892      their ancestors.
   893 
   894 In order to increase the readability of the list produced by
   895 unused_thms, theorems that have been created by a particular instance
   896 of a theory command such as 'inductive' or 'function' are considered
   897 to belong to the same "group", meaning that if at least one theorem in
   898 this group is used, the other theorems in the same group are no longer
   899 reported as unused.  Moreover, if all theorems in the group are
   900 unused, only one theorem in the group is displayed.
   901 
   902 Note that proof objects have to be switched on in order for
   903 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   904 usually the case when using Proof General with the default settings).
   905 
   906 * Authentic naming of facts disallows ad-hoc overwriting of previous
   907 theorems within the same name space.  INCOMPATIBILITY, need to remove
   908 duplicate fact bindings, or even accidental fact duplications.  Note
   909 that tools may maintain dynamically scoped facts systematically, using
   910 PureThy.add_thms_dynamic.
   911 
   912 * Command 'hide' now allows to hide from "fact" name space as well.
   913 
   914 * Eliminated destructive theorem database, simpset, claset, and
   915 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   916 update of theories within ML code.
   917 
   918 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   919 INCOMPATIBILITY, object-logics depending on former Pure require
   920 additional setup PureThy.old_appl_syntax_setup; object-logics
   921 depending on former CPure need to refer to Pure.
   922 
   923 * Commands 'use' and 'ML' are now purely functional, operating on
   924 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   925 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   926 INCOMPATIBILITY.
   927 
   928 * Command 'setup': discontinued implicit version with ML reference.
   929 
   930 * Instantiation target allows for simultaneous specification of class
   931 instance operations together with an instantiation proof.
   932 Type-checking phase allows to refer to class operations uniformly.
   933 See src/HOL/Complex/Complex.thy for an Isar example and
   934 src/HOL/Library/Eval.thy for an ML example.
   935 
   936 * Indexing of literal facts: be more serious about including only
   937 facts from the visible specification/proof context, but not the
   938 background context (locale etc.).  Affects `prop` notation and method
   939 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   940 situations.
   941 
   942 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   943 "(open)" option, which used to expose internal bound variables to the
   944 proof text.
   945 
   946 * Isar statements: removed obsolete case "rule_context".
   947 INCOMPATIBILITY, better use explicit fixes/assumes.
   948 
   949 * Locale proofs: default proof step now includes 'unfold_locales';
   950 hence 'proof' without argument may be used to unfold locale
   951 predicates.
   952 
   953 
   954 *** Document preparation ***
   955 
   956 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   957 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   958 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   959 spot); renamed link color from "darkblue" to "linkcolor" (default
   960 value unchanged, can be redefined via \definecolor); no longer sets
   961 "a4paper" option (unnecessary or even intrusive).
   962 
   963 * Antiquotation @{lemma A method} proves proposition A by the given
   964 method (either a method name or a method name plus (optional) method
   965 arguments in parentheses) and prints A just like @{prop A}.
   966 
   967 
   968 *** HOL ***
   969 
   970 * New primrec package.  Specification syntax conforms in style to
   971 definition/function/....  No separate induction rule is provided.  The
   972 "primrec" command distinguishes old-style and new-style specifications
   973 by syntax.  The former primrec package is now named OldPrimrecPackage.
   974 When adjusting theories, beware: constants stemming from new-style
   975 primrec specifications have authentic syntax.
   976 
   977 * Metis prover is now an order of magnitude faster, and also works
   978 with multithreading.
   979 
   980 * Metis: the maximum number of clauses that can be produced from a
   981 theorem is now given by the attribute max_clauses.  Theorems that
   982 exceed this number are ignored, with a warning printed.
   983 
   984 * Sledgehammer no longer produces structured proofs by default. To
   985 enable, declare [[sledgehammer_full = true]].  Attributes
   986 reconstruction_modulus, reconstruction_sorts renamed
   987 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   988 
   989 * Method "induct_scheme" derives user-specified induction rules
   990 from well-founded induction and completeness of patterns. This factors
   991 out some operations that are done internally by the function package
   992 and makes them available separately.  See
   993 src/HOL/ex/Induction_Scheme.thy for examples.
   994 
   995 * More flexible generation of measure functions for termination
   996 proofs: Measure functions can be declared by proving a rule of the
   997 form "is_measure f" and giving it the [measure_function] attribute.
   998 The "is_measure" predicate is logically meaningless (always true), and
   999 just guides the heuristic.  To find suitable measure functions, the
  1000 termination prover sets up the goal "is_measure ?f" of the appropriate
  1001 type and generates all solutions by prolog-style backwards proof using
  1002 the declared rules.
  1003 
  1004 This setup also deals with rules like 
  1005 
  1006   "is_measure f ==> is_measure (list_size f)"
  1007 
  1008 which accommodates nested datatypes that recurse through lists.
  1009 Similar rules are predeclared for products and option types.
  1010 
  1011 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
  1012 
  1013   INCOMPATIBILITIES:
  1014 
  1015   - Definitions of overloaded constants on sets have to be replaced by
  1016     definitions on => and bool.
  1017 
  1018   - Some definitions of overloaded operators on sets can now be proved
  1019     using the definitions of the operators on => and bool.  Therefore,
  1020     the following theorems have been renamed:
  1021 
  1022       subset_def   -> subset_eq
  1023       psubset_def  -> psubset_eq
  1024       set_diff_def -> set_diff_eq
  1025       Compl_def    -> Compl_eq
  1026       Sup_set_def  -> Sup_set_eq
  1027       Inf_set_def  -> Inf_set_eq
  1028       sup_set_def  -> sup_set_eq
  1029       inf_set_def  -> inf_set_eq
  1030 
  1031   - Due to the incompleteness of the HO unification algorithm, some
  1032     rules such as subst may require manual instantiation, if some of
  1033     the unknowns in the rule is a set.
  1034 
  1035   - Higher order unification and forward proofs:
  1036     The proof pattern
  1037 
  1038       have "P (S::'a set)" <...>
  1039       then have "EX S. P S" ..
  1040 
  1041     no longer works (due to the incompleteness of the HO unification
  1042     algorithm) and must be replaced by the pattern
  1043 
  1044       have "EX S. P S"
  1045       proof
  1046         show "P S" <...>
  1047       qed
  1048 
  1049   - Calculational reasoning with subst (or similar rules):
  1050     The proof pattern
  1051 
  1052       have "P (S::'a set)" <...>
  1053       also have "S = T" <...>
  1054       finally have "P T" .
  1055 
  1056     no longer works (for similar reasons as the previous example) and
  1057     must be replaced by something like
  1058 
  1059       have "P (S::'a set)" <...>
  1060       moreover have "S = T" <...>
  1061       ultimately have "P T" by simp
  1062 
  1063   - Tactics or packages written in ML code:
  1064     Code performing pattern matching on types via
  1065 
  1066       Type ("set", [T]) => ...
  1067 
  1068     must be rewritten. Moreover, functions like strip_type or
  1069     binder_types no longer return the right value when applied to a
  1070     type of the form
  1071 
  1072       T1 => ... => Tn => U => bool
  1073 
  1074     rather than
  1075 
  1076       T1 => ... => Tn => U set
  1077 
  1078 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1079 Wellfounded_Relations to theory Wellfounded.
  1080 
  1081 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1082 
  1083 * Class finite no longer treats UNIV as class parameter.  Use class
  1084 enum from theory Library/Enum instead to achieve a similar effect.
  1085 INCOMPATIBILITY.
  1086 
  1087 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1088 and "Cons".  INCOMPATIBILITY.
  1089 
  1090 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1091 Potential INCOMPATIBILITY.
  1092 
  1093 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1094 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1095 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1096 
  1097 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1098 the same name in theory Orderings:
  1099 
  1100   less_trans
  1101   less_linear
  1102   le_imp_less_or_eq
  1103   le_less_trans
  1104   less_le_trans
  1105   less_not_sym
  1106   less_asym
  1107 
  1108 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1109 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1110 and different variable names.
  1111 
  1112 * Library/Option_ord.thy: Canonical order on option type.
  1113 
  1114 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1115 finite maps.
  1116 
  1117 * Library/Countable.thy: Type class for countable types.
  1118 
  1119 * Theory Int: The representation of numerals has changed.  The infix
  1120 operator BIT and the bit datatype with constructors B0 and B1 have
  1121 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1122 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1123 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1124 accordingly.
  1125 
  1126 * Theory Nat: definition of <= and < on natural numbers no longer
  1127 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1128 le_def and less_def have disappeared.  Consider lemmas not_less
  1129 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1130 
  1131 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1132 (whose purpose mainly is for various fold_set functionals) have been
  1133 abandoned in favor of the existing algebraic classes
  1134 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1135 lower_semilattice (resp. upper_semilattice) and linorder.
  1136 INCOMPATIBILITY.
  1137 
  1138 * Theory Transitive_Closure: induct and cases rules now declare proper
  1139 case_names ("base" and "step").  INCOMPATIBILITY.
  1140 
  1141 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1142 lattices.  The form set-specific version is available as
  1143 Inductive.lfp_ordinal_induct_set.
  1144 
  1145 * Renamed theorems "power.simps" to "power_int.simps".
  1146 INCOMPATIBILITY.
  1147 
  1148 * Class semiring_div provides basic abstract properties of semirings
  1149 with division and modulo operations.  Subsumes former class dvd_mod.
  1150 
  1151 * Merged theories IntDef, Numeral and IntArith into unified theory
  1152 Int.  INCOMPATIBILITY.
  1153 
  1154 * Theory Library/Code_Index: type "index" now represents natural
  1155 numbers rather than integers.  INCOMPATIBILITY.
  1156 
  1157 * New class "uminus" with operation "uminus" (split of from class
  1158 "minus" which now only has operation "minus", binary).
  1159 INCOMPATIBILITY.
  1160 
  1161 * Constants "card", "internal_split", "option_map" now with authentic
  1162 syntax.  INCOMPATIBILITY.
  1163 
  1164 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1165 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1166 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1167 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1168 Sup_set_def, le_def, less_def, option_map_def now with object
  1169 equality.  INCOMPATIBILITY.
  1170 
  1171 * Records. Removed K_record, and replaced it by pure lambda term
  1172 %x. c. The simplifier setup is now more robust against eta expansion.
  1173 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1174 
  1175 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1176 
  1177 * Library/ListVector: new theory of arithmetic vector operations.
  1178 
  1179 * Library/Order_Relation: new theory of various orderings as sets of
  1180 pairs.  Defines preorders, partial orders, linear orders and
  1181 well-orders on sets and on types.
  1182 
  1183 
  1184 *** ZF ***
  1185 
  1186 * Renamed some theories to allow to loading both ZF and HOL in the
  1187 same session:
  1188 
  1189   Datatype  -> Datatype_ZF
  1190   Inductive -> Inductive_ZF
  1191   Int       -> Int_ZF
  1192   IntDiv    -> IntDiv_ZF
  1193   Nat       -> Nat_ZF
  1194   List      -> List_ZF
  1195   Main      -> Main_ZF
  1196 
  1197 INCOMPATIBILITY: ZF theories that import individual theories below
  1198 Main might need to be adapted.  Regular theory Main is still
  1199 available, as trivial extension of Main_ZF.
  1200 
  1201 
  1202 *** ML ***
  1203 
  1204 * ML within Isar: antiquotation @{const name} or @{const
  1205 name(typargs)} produces statically-checked Const term.
  1206 
  1207 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1208 (of the same name).  Removed obsolete print command.
  1209 
  1210 * Removed obsolete "use_legacy_bindings" function.
  1211 
  1212 * The ``print mode'' is now a thread-local value derived from a global
  1213 template (the former print_mode reference), thus access becomes
  1214 non-critical.  The global print_mode reference is for session
  1215 management only; user-code should use print_mode_value,
  1216 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1217 
  1218 * Functions system/system_out provide a robust way to invoke external
  1219 shell commands, with propagation of interrupts (requires Poly/ML
  1220 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1221 
  1222 
  1223 *** System ***
  1224 
  1225 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1226 in accordance with Proof General 3.7, which prefers GNU emacs.
  1227 
  1228 * isatool tty runs Isabelle process with plain tty interaction;
  1229 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1230 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1231 
  1232 * isatool browser now works with Cygwin as well, using general
  1233 "javapath" function defined in Isabelle process environment.
  1234 
  1235 * YXML notation provides a simple and efficient alternative to
  1236 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1237 isatool yxml as described in the Isabelle system manual.
  1238 
  1239 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1240 provides general wrapper for managing an Isabelle process in a robust
  1241 fashion, with ``cooked'' output from stdin/stderr.
  1242 
  1243 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1244 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1245 
  1246 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1247 way of changing the user's settings is via
  1248 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1249 script.
  1250 
  1251 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1252 cores of the underlying machine, which is a good starting point for
  1253 optimal performance tuning.  The corresponding usedir option -M allows
  1254 "max" as an alias for "0".  WARNING: does not work on certain versions
  1255 of Mac OS (with Poly/ML 5.1).
  1256 
  1257 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1258 adverse effect of Isabelle flooding interactive front-ends (notably
  1259 ProofGeneral / XEmacs).
  1260 
  1261 
  1262 
  1263 New in Isabelle2007 (November 2007)
  1264 -----------------------------------
  1265 
  1266 *** General ***
  1267 
  1268 * More uniform information about legacy features, notably a
  1269 warning/error of "Legacy feature: ...", depending on the state of the
  1270 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1271 legacy features will disappear eventually.
  1272 
  1273 * Theory syntax: the header format ``theory A = B + C:'' has been
  1274 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1275 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1276 
  1277 * Theory syntax: the old non-Isar theory file format has been
  1278 discontinued altogether.  Note that ML proof scripts may still be used
  1279 with Isar theories; migration is usually quite simple with the ML
  1280 function use_legacy_bindings.  INCOMPATIBILITY.
  1281 
  1282 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1283 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1284 quotes.
  1285 
  1286 * Theory loader: be more serious about observing the static theory
  1287 header specifications (including optional directories), but not the
  1288 accidental file locations of previously successful loads.  The strict
  1289 update policy of former update_thy is now already performed by
  1290 use_thy, so the former has been removed; use_thys updates several
  1291 theories simultaneously, just as 'imports' within a theory header
  1292 specification, but without merging the results.  Potential
  1293 INCOMPATIBILITY: may need to refine theory headers and commands
  1294 ROOT.ML which depend on load order.
  1295 
  1296 * Theory loader: optional support for content-based file
  1297 identification, instead of the traditional scheme of full physical
  1298 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1299 (cf. the system manual).  The new scheme allows to work with
  1300 non-finished theories in persistent session images, such that source
  1301 files may be moved later on without requiring reloads.
  1302 
  1303 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1304 file (with the same base name as the theory) are considered a legacy
  1305 feature, which will disappear eventually. Even now, the theory loader
  1306 no longer maintains dependencies on such files.
  1307 
  1308 * Syntax: the scope for resolving ambiguities via type-inference is
  1309 now limited to individual terms, instead of whole simultaneous
  1310 specifications as before. This greatly reduces the complexity of the
  1311 syntax module and improves flexibility by separating parsing and
  1312 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1313 'fixes' etc.) are required in rare situations.
  1314 
  1315 * Syntax: constants introduced by new-style packages ('definition',
  1316 'abbreviation' etc.) are passed through the syntax module in
  1317 ``authentic mode''. This means that associated mixfix annotations
  1318 really stick to such constants, independently of potential name space
  1319 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1320 trees are represented slightly differently, may need to adapt syntax
  1321 translations accordingly. Use CONST marker in 'translations' and
  1322 @{const_syntax} antiquotation in 'parse_translation' etc.
  1323 
  1324 * Legacy goal package: reduced interface to the bare minimum required
  1325 to keep existing proof scripts running.  Most other user-level
  1326 functions are now part of the OldGoals structure, which is *not* open
  1327 by default (consider isatool expandshort before open OldGoals).
  1328 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1329 these tend to cause confusion about the actual goal (!) context being
  1330 used here, which is not necessarily the same as the_context().
  1331 
  1332 * Command 'find_theorems': supports "*" wild-card in "name:"
  1333 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1334 support a specific search form (see ProofGeneral/CHANGES).
  1335 
  1336 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1337 by default, which means that "prems" (and also "fixed variables") are
  1338 suppressed from proof state output.  Note that the ProofGeneral
  1339 settings mechanism allows to change and save options persistently, but
  1340 older versions of Isabelle will fail to start up if a negative prems
  1341 limit is imposed.
  1342 
  1343 * Local theory targets may be specified by non-nested blocks of
  1344 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1345 contain definitions, theorems etc., including any derived mechanism
  1346 that has been implemented on top of these primitives.  This concept
  1347 generalizes the existing ``theorem (in ...)'' towards more versatility
  1348 and scalability.
  1349 
  1350 * Proof General interface: proper undo of final 'end' command;
  1351 discontinued Isabelle/classic mode (ML proof scripts).
  1352 
  1353 
  1354 *** Document preparation ***
  1355 
  1356 * Added antiquotation @{theory name} which prints the given name,
  1357 after checking that it refers to a valid ancestor theory in the
  1358 current context.
  1359 
  1360 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1361 check the given source text as ML type/structure, printing verbatim.
  1362 
  1363 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1364 "c args == rhs" given in the current context.  (Any number of
  1365 arguments may be given on the LHS.)
  1366 
  1367 
  1368 *** Pure ***
  1369 
  1370 * The 'class' package offers a combination of axclass and locale to
  1371 achieve Haskell-like type classes in Isabelle.  Definitions and
  1372 theorems within a class context produce both relative results (with
  1373 implicit parameters according to the locale context), and polymorphic
  1374 constants with qualified polymorphism (according to the class
  1375 context).  Within the body context of a 'class' target, a separate
  1376 syntax layer ("user space type system") takes care of converting
  1377 between global polymorphic consts and internal locale representation.
  1378 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1379 "isatool doc classes" provides a tutorial.
  1380 
  1381 * Generic code generator framework allows to generate executable
  1382 code for ML and Haskell (including Isabelle classes).  A short usage
  1383 sketch:
  1384 
  1385     internal compilation:
  1386         export_code <list of constants (term syntax)> in SML
  1387     writing SML code to a file:
  1388         export_code <list of constants (term syntax)> in SML <filename>
  1389     writing OCaml code to a file:
  1390         export_code <list of constants (term syntax)> in OCaml <filename>
  1391     writing Haskell code to a bunch of files:
  1392         export_code <list of constants (term syntax)> in Haskell <filename>
  1393 
  1394     evaluating closed propositions to True/False using code generation:
  1395         method ``eval''
  1396 
  1397 Reasonable default setup of framework in HOL.
  1398 
  1399 Theorem attributs for selecting and transforming function equations theorems:
  1400 
  1401     [code fun]:        select a theorem as function equation for a specific constant
  1402     [code fun del]:    deselect a theorem as function equation for a specific constant
  1403     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1404     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1405 
  1406 User-defined serializations (target in {SML, OCaml, Haskell}):
  1407 
  1408     code_const <and-list of constants (term syntax)>
  1409       {(target) <and-list of const target syntax>}+
  1410 
  1411     code_type <and-list of type constructors>
  1412       {(target) <and-list of type target syntax>}+
  1413 
  1414     code_instance <and-list of instances>
  1415       {(target)}+
  1416         where instance ::= <type constructor> :: <class>
  1417 
  1418     code_class <and_list of classes>
  1419       {(target) <and-list of class target syntax>}+
  1420         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1421 
  1422 code_instance and code_class only are effective to target Haskell.
  1423 
  1424 For example usage see src/HOL/ex/Codegenerator.thy and
  1425 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1426 generation from Isabelle/HOL theories is available via "isatool doc
  1427 codegen".
  1428 
  1429 * Code generator: consts in 'consts_code' Isar commands are now
  1430 referred to by usual term syntax (including optional type
  1431 annotations).
  1432 
  1433 * Command 'no_translations' removes translation rules from theory
  1434 syntax.
  1435 
  1436 * Overloaded definitions are now actually checked for acyclic
  1437 dependencies.  The overloading scheme is slightly more general than
  1438 that of Haskell98, although Isabelle does not demand an exact
  1439 correspondence to type class and instance declarations.
  1440 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1441 exotic versions of overloading -- at the discretion of the user!
  1442 
  1443 Polymorphic constants are represented via type arguments, i.e. the
  1444 instantiation that matches an instance against the most general
  1445 declaration given in the signature.  For example, with the declaration
  1446 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1447 as c(nat).  Overloading is essentially simultaneous structural
  1448 recursion over such type arguments.  Incomplete specification patterns
  1449 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1450 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1451 Command 'print_theory' outputs the normalized system of recursive
  1452 equations, see section "definitions".
  1453 
  1454 * Configuration options are maintained within the theory or proof
  1455 context (with name and type bool/int/string), providing a very simple
  1456 interface to a poor-man's version of general context data.  Tools may
  1457 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1458 these values using Config.get etc.  Users may change options via an
  1459 associated attribute of the same name.  This form of context
  1460 declaration works particularly well with commands 'declare' or
  1461 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1462 very easy to avoid global references, which would not observe Isar
  1463 toplevel undo/redo and fail to work with multithreading.
  1464 
  1465 Various global ML references of Pure and HOL have been turned into
  1466 configuration options:
  1467 
  1468   Unify.search_bound		unify_search_bound
  1469   Unify.trace_bound		unify_trace_bound
  1470   Unify.trace_simp		unify_trace_simp
  1471   Unify.trace_types		unify_trace_types
  1472   Simplifier.simp_depth_limit	simp_depth_limit
  1473   Blast.depth_limit		blast_depth_limit
  1474   DatatypeProp.dtK		datatype_distinctness_limit
  1475   fast_arith_neq_limit  	fast_arith_neq_limit
  1476   fast_arith_split_limit	fast_arith_split_limit
  1477 
  1478 * Named collections of theorems may be easily installed as context
  1479 data using the functor NamedThmsFun (see also
  1480 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1481 attributes; there is also a toplevel print command.  This facility is
  1482 just a common case of general context data, which is the preferred way
  1483 for anything more complex than just a list of facts in canonical
  1484 order.
  1485 
  1486 * Isar: command 'declaration' augments a local theory by generic
  1487 declaration functions written in ML.  This enables arbitrary content
  1488 being added to the context, depending on a morphism that tells the
  1489 difference of the original declaration context wrt. the application
  1490 context encountered later on.
  1491 
  1492 * Isar: proper interfaces for simplification procedures.  Command
  1493 'simproc_setup' declares named simprocs (with match patterns, and body
  1494 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1495 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1496 
  1497 * Isar: an extra pair of brackets around attribute declarations
  1498 abbreviates a theorem reference involving an internal dummy fact,
  1499 which will be ignored later --- only the effect of the attribute on
  1500 the background context will persist.  This form of in-place
  1501 declarations is particularly useful with commands like 'declare' and
  1502 'using', for example ``have A using [[simproc a]] by simp''.
  1503 
  1504 * Isar: method "assumption" (and implicit closing of subproofs) now
  1505 takes simple non-atomic goal assumptions into account: after applying
  1506 an assumption as a rule the resulting subgoals are solved by atomic
  1507 assumption steps.  This is particularly useful to finish 'obtain'
  1508 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1509 without referring to the original premise "!!x. P x ==> thesis" in the
  1510 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1511 more permissive.
  1512 
  1513 * Isar: implicit use of prems from the Isar proof context is
  1514 considered a legacy feature.  Common applications like ``have A .''
  1515 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1516 referencing facts explicitly here improves readability and
  1517 maintainability of proof texts.
  1518 
  1519 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1520 the obtained context from the course of reasoning!  For example:
  1521 
  1522   assume "EX x y. A x & B y"   -- "any previous fact"
  1523   then guess x and y by clarify
  1524 
  1525 This technique is potentially adventurous, depending on the facts and
  1526 proof tools being involved here.
  1527 
  1528 * Isar: known facts from the proof context may be specified as literal
  1529 propositions, using ASCII back-quote syntax.  This works wherever
  1530 named facts used to be allowed so far, in proof commands, proof
  1531 methods, attributes etc.  Literal facts are retrieved from the context
  1532 according to unification of type and term parameters.  For example,
  1533 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1534 theorems in the current context, then these are valid literal facts:
  1535 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1536 
  1537 There is also a proof method "fact" which does the same composition
  1538 for explicit goal states, e.g. the following proof texts coincide with
  1539 certain special cases of literal facts:
  1540 
  1541   have "A" by fact                 ==  note `A`
  1542   have "A ==> B" by fact           ==  note `A ==> B`
  1543   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1544   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1545 
  1546 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1547 outer syntax.  Thus symbolic identifiers may be used without
  1548 additional white space in declarations like this: ``assume *: A''.
  1549 
  1550 * Isar: 'print_facts' prints all local facts of the current context,
  1551 both named and unnamed ones.
  1552 
  1553 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1554 
  1555   def x == "t" and y == "u"
  1556 
  1557 * Isar: added command 'unfolding', which is structurally similar to
  1558 'using', but affects both the goal state and facts by unfolding given
  1559 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1560 'unfolded' attribute may be replaced by first-class proof text.
  1561 
  1562 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1563 and command 'unfolding' now all support object-level equalities
  1564 (potentially conditional).  The underlying notion of rewrite rule is
  1565 analogous to the 'rule_format' attribute, but *not* that of the
  1566 Simplifier (which is usually more generous).
  1567 
  1568 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1569 premises of a theorem by n. Useful in conjunction with drule.
  1570 
  1571 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1572 method expression within a sandbox consisting of the first N
  1573 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1574 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1575 simplifies all new goals that emerge from applying rule foo to the
  1576 originally first one.
  1577 
  1578 * Isar: schematic goals are no longer restricted to higher-order
  1579 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1580 expected.
  1581 
  1582 * Isar: the conclusion of a long theorem statement is now either
  1583 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1584 (essentially a disjunction of cases with local parameters and
  1585 assumptions).  The latter allows to express general elimination rules
  1586 adequately; in this notation common elimination rules look like this:
  1587 
  1588   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1589     assumes "EX x. P x"
  1590     obtains x where "P x"
  1591 
  1592   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1593     assumes "A & B"
  1594     obtains A and B
  1595 
  1596   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1597     assumes "A | B"
  1598     obtains
  1599       A
  1600     | B
  1601 
  1602 The subsequent classical rules even refer to the formal "thesis"
  1603 explicitly:
  1604 
  1605   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1606     obtains "~ thesis"
  1607 
  1608   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1609     obtains "thesis ==> something"
  1610 
  1611 The actual proof of an 'obtains' statement is analogous to that of the
  1612 Isar proof element 'obtain', only that there may be several cases.
  1613 Optional case names may be specified in parentheses; these will be
  1614 available both in the present proof and as annotations in the
  1615 resulting rule, for later use with the 'cases' method (cf. attribute
  1616 case_names).
  1617 
  1618 * Isar: the assumptions of a long theorem statement are available as
  1619 "assms" fact in the proof context.  This is more appropriate than the
  1620 (historical) "prems", which refers to all assumptions of the current
  1621 context, including those from the target locale, proof body etc.
  1622 
  1623 * Isar: 'print_statement' prints theorems from the current theory or
  1624 proof context in long statement form, according to the syntax of a
  1625 top-level lemma.
  1626 
  1627 * Isar: 'obtain' takes an optional case name for the local context
  1628 introduction rule (default "that").
  1629 
  1630 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1631 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1632 to occur.
  1633 
  1634 * Pure: syntax "CONST name" produces a fully internalized constant
  1635 according to the current context.  This is particularly useful for
  1636 syntax translations that should refer to internal constant
  1637 representations independently of name spaces.
  1638 
  1639 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1640 instead of "FOO ". This allows multiple binder declarations to coexist
  1641 in the same context.  INCOMPATIBILITY.
  1642 
  1643 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1644 primitive that also works in a locale context (both for constants and
  1645 fixed variables). Type declaration and internal syntactic representation
  1646 of given constants retrieved from the context. Likewise, the
  1647 'no_notation' command allows to remove given syntax annotations from the
  1648 current context.
  1649 
  1650 * Isar/locales: new derived specification elements 'axiomatization',
  1651 'definition', 'abbreviation', which support type-inference, admit
  1652 object-level specifications (equality, equivalence).  See also the
  1653 isar-ref manual.  Examples:
  1654 
  1655   axiomatization
  1656     eq  (infix "===" 50) where
  1657     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1658 
  1659   definition "f x y = x + y + 1"
  1660   definition g where "g x = f x x"
  1661 
  1662   abbreviation
  1663     neq  (infix "=!=" 50) where
  1664     "x =!= y == ~ (x === y)"
  1665 
  1666 These specifications may be also used in a locale context.  Then the
  1667 constants being introduced depend on certain fixed parameters, and the
  1668 constant name is qualified by the locale base name.  An internal
  1669 abbreviation takes care for convenient input and output, making the
  1670 parameters implicit and using the original short name.  See also
  1671 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1672 entities from a monomorphic theory.
  1673 
  1674 Presently, abbreviations are only available 'in' a target locale, but
  1675 not inherited by general import expressions.  Also note that
  1676 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1677 'translations' in common applications.  The "no_abbrevs" print mode
  1678 prevents folding of abbreviations in term output.
  1679 
  1680 Concrete syntax is attached to specified constants in internal form,
  1681 independently of name spaces.  The parse tree representation is
  1682 slightly different -- use 'notation' instead of raw 'syntax', and
  1683 'translations' with explicit "CONST" markup to accommodate this.
  1684 
  1685 * Pure/Isar: unified syntax for new-style specification mechanisms
  1686 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1687 full type inference and dummy patterns ("_").  For example:
  1688 
  1689   definition "K x _ = x"
  1690 
  1691   inductive conj for A B
  1692   where "A ==> B ==> conj A B"
  1693 
  1694 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1695 the current context.  Print mode "no_abbrevs" prevents inversion of
  1696 abbreviations on output.
  1697 
  1698 * Isar/locales: improved parameter handling: use of locales "var" and
  1699 "struct" no longer necessary; - parameter renamings are no longer
  1700 required to be injective.  For example, this allows to define
  1701 endomorphisms as locale endom = homom mult mult h.
  1702 
  1703 * Isar/locales: changed the way locales with predicates are defined.
  1704 Instead of accumulating the specification, the imported expression is
  1705 now an interpretation.  INCOMPATIBILITY: different normal form of
  1706 locale expressions.  In particular, in interpretations of locales with
  1707 predicates, goals repesenting already interpreted fragments are not
  1708 removed automatically.  Use methods `intro_locales' and
  1709 `unfold_locales'; see below.
  1710 
  1711 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1712 provide backward reasoning on locales predicates.  The methods are
  1713 aware of interpretations and discharge corresponding goals.
  1714 `intro_locales' is less aggressive then `unfold_locales' and does not
  1715 unfold predicates to assumptions.
  1716 
  1717 * Isar/locales: the order in which locale fragments are accumulated
  1718 has changed.  This enables to override declarations from fragments due
  1719 to interpretations -- for example, unwanted simp rules.
  1720 
  1721 * Isar/locales: interpretation in theories and proof contexts has been
  1722 extended.  One may now specify (and prove) equations, which are
  1723 unfolded in interpreted theorems.  This is useful for replacing
  1724 defined concepts (constants depending on locale parameters) by
  1725 concepts already existing in the target context.  Example:
  1726 
  1727   interpretation partial_order ["op <= :: [int, int] => bool"]
  1728     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1729 
  1730 Typically, the constant `partial_order.less' is created by a
  1731 definition specification element in the context of locale
  1732 partial_order.
  1733 
  1734 * Method "induct": improved internal context management to support
  1735 local fixes and defines on-the-fly. Thus explicit meta-level
  1736 connectives !!  and ==> are rarely required anymore in inductive goals
  1737 (using object-logic connectives for this purpose has been long
  1738 obsolete anyway). Common proof patterns are explained in
  1739 src/HOL/Induct/Common_Patterns.thy, see also
  1740 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1741 examples.
  1742 
  1743 * Method "induct": improved handling of simultaneous goals. Instead of
  1744 introducing object-level conjunction, the statement is now split into
  1745 several conclusions, while the corresponding symbolic cases are nested
  1746 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1747 see src/HOL/Induct/Common_Patterns.thy, for example.
  1748 
  1749 * Method "induct": mutual induction rules are now specified as a list
  1750 of rule sharing the same induction cases. HOL packages usually provide
  1751 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1752 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1753 mutual induction rules differently, i.e. like this:
  1754 
  1755   (induct rule: foo_bar.inducts)
  1756   (induct set: foo bar)
  1757   (induct pred: foo bar)
  1758   (induct type: foo bar)
  1759 
  1760 The ML function ProjectRule.projections turns old-style rules into the
  1761 new format.
  1762 
  1763 * Method "coinduct": dual of induction, see
  1764 src/HOL/Library/Coinductive_List.thy for various examples.
  1765 
  1766 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1767 considered a legacy feature.
  1768 
  1769 * Attribute "symmetric" produces result with standardized schematic
  1770 variables (index 0).  Potential INCOMPATIBILITY.
  1771 
  1772 * Simplifier: by default the simplifier trace only shows top level
  1773 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1774 default. Thus there is less danger of being flooded by the trace. The
  1775 trace indicates where parts have been suppressed.
  1776   
  1777 * Provers/classical: removed obsolete classical version of elim_format
  1778 attribute; classical elim/dest rules are now treated uniformly when
  1779 manipulating the claset.
  1780 
  1781 * Provers/classical: stricter checks to ensure that supplied intro,
  1782 dest and elim rules are well-formed; dest and elim rules must have at
  1783 least one premise.
  1784 
  1785 * Provers/classical: attributes dest/elim/intro take an optional
  1786 weight argument for the rule (just as the Pure versions).  Weights are
  1787 ignored by automated tools, but determine the search order of single
  1788 rule steps.
  1789 
  1790 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1791 where the body does not mention the bound variable.  Note that dummy
  1792 patterns implicitly depend on their context of bounds, which makes
  1793 "{_. _}" match any set comprehension as expected.  Potential
  1794 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1795 constant "_idtdummy" in the binding position.
  1796 
  1797 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1798 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1799 for example "A -> B" => "Pi A (%_. B)".
  1800 
  1801 * Pure: 'class_deps' command visualizes the subclass relation, using
  1802 the graph browser tool.
  1803 
  1804 * Pure: 'print_theory' now suppresses certain internal declarations by
  1805 default; use '!' option for full details.
  1806 
  1807 
  1808 *** HOL ***
  1809 
  1810 * Method "metis" proves goals by applying the Metis general-purpose
  1811 resolution prover (see also http://gilith.com/software/metis/).
  1812 Examples are in the directory MetisExamples.  WARNING: the
  1813 Isabelle/HOL-Metis integration does not yet work properly with
  1814 multi-threading.
  1815   
  1816 * Command 'sledgehammer' invokes external automatic theorem provers as
  1817 background processes.  It generates calls to the "metis" method if
  1818 successful. These can be pasted into the proof.  Users do not have to
  1819 wait for the automatic provers to return.  WARNING: does not really
  1820 work with multi-threading.
  1821 
  1822 * New "auto_quickcheck" feature tests outermost goal statements for
  1823 potential counter-examples.  Controlled by ML references
  1824 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1825 5000 milliseconds).  Fails silently if statements is outside of
  1826 executable fragment, or any other codgenerator problem occurs.
  1827 
  1828 * New constant "undefined" with axiom "undefined x = undefined".
  1829 
  1830 * Added class "HOL.eq", allowing for code generation with polymorphic
  1831 equality.
  1832 
  1833 * Some renaming of class constants due to canonical name prefixing in
  1834 the new 'class' package:
  1835 
  1836     HOL.abs ~> HOL.abs_class.abs
  1837     HOL.divide ~> HOL.divide_class.divide
  1838     0 ~> HOL.zero_class.zero
  1839     1 ~> HOL.one_class.one
  1840     op + ~> HOL.plus_class.plus
  1841     op - ~> HOL.minus_class.minus
  1842     uminus ~> HOL.minus_class.uminus
  1843     op * ~> HOL.times_class.times
  1844     op < ~> HOL.ord_class.less
  1845     op <= > HOL.ord_class.less_eq
  1846     Nat.power ~> Power.power_class.power
  1847     Nat.size ~> Nat.size_class.size
  1848     Numeral.number_of ~> Numeral.number_class.number_of
  1849     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1850     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1851     Orderings.min ~> Orderings.ord_class.min
  1852     Orderings.max ~> Orderings.ord_class.max
  1853     Divides.op div ~> Divides.div_class.div
  1854     Divides.op mod ~> Divides.div_class.mod
  1855     Divides.op dvd ~> Divides.div_class.dvd
  1856 
  1857 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1858 
  1859 a) User-defined constants using any of the names "plus", "minus",
  1860 "times", "less" or "less_eq". The standard syntax translations for
  1861 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1862 names.
  1863 
  1864 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1865 INCOMPATIBILITY: use more specific names.
  1866 
  1867 c) Permutative equations (e.g. "a + b = b + a")
  1868 Since the change of names also changes the order of terms, permutative
  1869 rewrite rules may get applied in a different order. Experience shows
  1870 that this is rarely the case (only two adaptions in the whole Isabelle
  1871 distribution).  INCOMPATIBILITY: rewrite proofs
  1872 
  1873 d) ML code directly refering to constant names
  1874 This in general only affects hand-written proof tactics, simprocs and
  1875 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1876 Consider using @{const_name} antiquotation.
  1877 
  1878 * New class "default" with associated constant "default".
  1879 
  1880 * Function "sgn" is now overloaded and available on int, real, complex
  1881 (and other numeric types), using class "sgn".  Two possible defs of
  1882 sgn are given as equational assumptions in the classes sgn_if and
  1883 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1884 INCOMPATIBILITY.
  1885 
  1886 * Locale "partial_order" now unified with class "order" (cf. theory
  1887 Orderings), added parameter "less".  INCOMPATIBILITY.
  1888 
  1889 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1890 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1891 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1892 
  1893 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1894 changed order of proof goals in instance proofs.
  1895 
  1896 * The transitivity reasoner for partial and linear orders is set up
  1897 for classes "order" and "linorder".  Instances of the reasoner are available
  1898 in all contexts importing or interpreting the corresponding locales.
  1899 Method "order" invokes the reasoner separately; the reasoner
  1900 is also integrated with the Simplifier as a solver.  Diagnostic
  1901 command 'print_orders' shows the available instances of the reasoner
  1902 in the current context.
  1903 
  1904 * Localized monotonicity predicate in theory "Orderings"; integrated
  1905 lemmas max_of_mono and min_of_mono with this predicate.
  1906 INCOMPATIBILITY.
  1907 
  1908 * Formulation of theorem "dense" changed slightly due to integration
  1909 with new class dense_linear_order.
  1910 
  1911 * Uniform lattice theory development in HOL.
  1912 
  1913     constants "meet" and "join" now named "inf" and "sup"
  1914     constant "Meet" now named "Inf"
  1915 
  1916     classes "meet_semilorder" and "join_semilorder" now named
  1917       "lower_semilattice" and "upper_semilattice"
  1918     class "lorder" now named "lattice"
  1919     class "comp_lat" now named "complete_lattice"
  1920 
  1921     Instantiation of lattice classes allows explicit definitions
  1922     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1923 
  1924   INCOMPATIBILITY.  Theorem renames:
  1925 
  1926     meet_left_le            ~> inf_le1
  1927     meet_right_le           ~> inf_le2
  1928     join_left_le            ~> sup_ge1
  1929     join_right_le           ~> sup_ge2
  1930     meet_join_le            ~> inf_sup_ord
  1931     le_meetI                ~> le_infI
  1932     join_leI                ~> le_supI
  1933     le_meet                 ~> le_inf_iff
  1934     le_join                 ~> ge_sup_conv
  1935     meet_idempotent         ~> inf_idem
  1936     join_idempotent         ~> sup_idem
  1937     meet_comm               ~> inf_commute
  1938     join_comm               ~> sup_commute
  1939     meet_leI1               ~> le_infI1
  1940     meet_leI2               ~> le_infI2
  1941     le_joinI1               ~> le_supI1
  1942     le_joinI2               ~> le_supI2
  1943     meet_assoc              ~> inf_assoc
  1944     join_assoc              ~> sup_assoc
  1945     meet_left_comm          ~> inf_left_commute
  1946     meet_left_idempotent    ~> inf_left_idem
  1947     join_left_comm          ~> sup_left_commute
  1948     join_left_idempotent    ~> sup_left_idem
  1949     meet_aci                ~> inf_aci
  1950     join_aci                ~> sup_aci
  1951     le_def_meet             ~> le_iff_inf
  1952     le_def_join             ~> le_iff_sup
  1953     join_absorp2            ~> sup_absorb2
  1954     join_absorp1            ~> sup_absorb1
  1955     meet_absorp1            ~> inf_absorb1
  1956     meet_absorp2            ~> inf_absorb2
  1957     meet_join_absorp        ~> inf_sup_absorb
  1958     join_meet_absorp        ~> sup_inf_absorb
  1959     distrib_join_le         ~> distrib_sup_le
  1960     distrib_meet_le         ~> distrib_inf_le
  1961 
  1962     add_meet_distrib_left   ~> add_inf_distrib_left
  1963     add_join_distrib_left   ~> add_sup_distrib_left
  1964     is_join_neg_meet        ~> is_join_neg_inf
  1965     is_meet_neg_join        ~> is_meet_neg_sup
  1966     add_meet_distrib_right  ~> add_inf_distrib_right
  1967     add_join_distrib_right  ~> add_sup_distrib_right
  1968     add_meet_join_distribs  ~> add_sup_inf_distribs
  1969     join_eq_neg_meet        ~> sup_eq_neg_inf
  1970     meet_eq_neg_join        ~> inf_eq_neg_sup
  1971     add_eq_meet_join        ~> add_eq_inf_sup
  1972     meet_0_imp_0            ~> inf_0_imp_0
  1973     join_0_imp_0            ~> sup_0_imp_0
  1974     meet_0_eq_0             ~> inf_0_eq_0
  1975     join_0_eq_0             ~> sup_0_eq_0
  1976     neg_meet_eq_join        ~> neg_inf_eq_sup
  1977     neg_join_eq_meet        ~> neg_sup_eq_inf
  1978     join_eq_if              ~> sup_eq_if
  1979 
  1980     mono_meet               ~> mono_inf
  1981     mono_join               ~> mono_sup
  1982     meet_bool_eq            ~> inf_bool_eq
  1983     join_bool_eq            ~> sup_bool_eq
  1984     meet_fun_eq             ~> inf_fun_eq
  1985     join_fun_eq             ~> sup_fun_eq
  1986     meet_set_eq             ~> inf_set_eq
  1987     join_set_eq             ~> sup_set_eq
  1988     meet1_iff               ~> inf1_iff
  1989     meet2_iff               ~> inf2_iff
  1990     meet1I                  ~> inf1I
  1991     meet2I                  ~> inf2I
  1992     meet1D1                 ~> inf1D1
  1993     meet2D1                 ~> inf2D1
  1994     meet1D2                 ~> inf1D2
  1995     meet2D2                 ~> inf2D2
  1996     meet1E                  ~> inf1E
  1997     meet2E                  ~> inf2E
  1998     join1_iff               ~> sup1_iff
  1999     join2_iff               ~> sup2_iff
  2000     join1I1                 ~> sup1I1
  2001     join2I1                 ~> sup2I1
  2002     join1I1                 ~> sup1I1
  2003     join2I2                 ~> sup1I2
  2004     join1CI                 ~> sup1CI
  2005     join2CI                 ~> sup2CI
  2006     join1E                  ~> sup1E
  2007     join2E                  ~> sup2E
  2008 
  2009     is_meet_Meet            ~> is_meet_Inf
  2010     Meet_bool_def           ~> Inf_bool_def
  2011     Meet_fun_def            ~> Inf_fun_def
  2012     Meet_greatest           ~> Inf_greatest
  2013     Meet_lower              ~> Inf_lower
  2014     Meet_set_def            ~> Inf_set_def
  2015 
  2016     Sup_def                 ~> Sup_Inf
  2017     Sup_bool_eq             ~> Sup_bool_def
  2018     Sup_fun_eq              ~> Sup_fun_def
  2019     Sup_set_eq              ~> Sup_set_def
  2020 
  2021     listsp_meetI            ~> listsp_infI
  2022     listsp_meet_eq          ~> listsp_inf_eq
  2023 
  2024     meet_min                ~> inf_min
  2025     join_max                ~> sup_max
  2026 
  2027 * Added syntactic class "size"; overloaded constant "size" now has
  2028 type "'a::size ==> bool"
  2029 
  2030 * Internal reorganisation of `size' of datatypes: size theorems
  2031 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2032 simplification rules by default!); theorems "prod.size" now named
  2033 "*.size".
  2034 
  2035 * Class "div" now inherits from class "times" rather than "type".
  2036 INCOMPATIBILITY.
  2037 
  2038 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2039 Linorder etc.  have disappeared; operations defined in terms of
  2040 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2041 
  2042 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2043 
  2044 * HOL-Word: New extensive library and type for generic, fixed size
  2045 machine words, with arithemtic, bit-wise, shifting and rotating
  2046 operations, reflection into int, nat, and bool lists, automation for
  2047 linear arithmetic (by automatic reflection into nat or int), including
  2048 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2049 arithmetic type classes, supporting automatic simplification of
  2050 numerals on all operations.
  2051 
  2052 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2053 
  2054 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2055 
  2056 * Code generator library theories:
  2057   - Code_Integer represents HOL integers by big integer literals in target
  2058     languages.
  2059   - Code_Char represents HOL characters by character literals in target
  2060     languages.
  2061   - Code_Char_chr like Code_Char, but also offers treatment of character
  2062     codes; includes Code_Integer.
  2063   - Executable_Set allows to generate code for finite sets using lists.
  2064   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2065     denominator).
  2066   - Executable_Real implements a subset of real numbers, namly those
  2067     representable by rational numbers.
  2068   - Efficient_Nat implements natural numbers by integers, which in general will
  2069     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2070     includes Code_Integer.
  2071   - Code_Index provides an additional datatype index which is mapped to
  2072     target-language built-in integers.
  2073   - Code_Message provides an additional datatype message_string which is isomorphic to
  2074     strings; messages are mapped to target-language strings.
  2075 
  2076 * New package for inductive predicates
  2077 
  2078   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2079 
  2080     inductive
  2081       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2082       for z_1 :: U_1 and ... and z_n :: U_m
  2083     where
  2084       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2085     | ...
  2086 
  2087   with full support for type-inference, rather than
  2088 
  2089     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2090 
  2091     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2092     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2093 
  2094     inductive "s z_1 ... z_m"
  2095     intros
  2096       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2097       ...
  2098 
  2099   For backward compatibility, there is a wrapper allowing inductive
  2100   sets to be defined with the new package via
  2101 
  2102     inductive_set
  2103       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2104       for z_1 :: U_1 and ... and z_n :: U_m
  2105     where
  2106       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2107     | ...
  2108 
  2109   or
  2110 
  2111     inductive_set
  2112       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2113       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2114       for z_1 :: U_1 and ... and z_n :: U_m
  2115     where
  2116       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2117     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2118     | ...
  2119 
  2120   if the additional syntax "p ..." is required.
  2121 
  2122   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2123   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2124 
  2125   INCOMPATIBILITIES:
  2126 
  2127   - Since declaration and definition of inductive sets or predicates
  2128     is no longer separated, abbreviations involving the newly
  2129     introduced sets or predicates must be specified together with the
  2130     introduction rules after the 'where' keyword (see above), rather
  2131     than before the actual inductive definition.
  2132 
  2133   - The variables in induction and elimination rules are now
  2134     quantified in the order of their occurrence in the introduction
  2135     rules, rather than in alphabetical order. Since this may break
  2136     some proofs, these proofs either have to be repaired, e.g. by
  2137     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2138     statements of the form
  2139 
  2140       case (rule_i a_i_1 ... a_i_{k_i})
  2141 
  2142     or the old order of quantification has to be restored by explicitly adding
  2143     meta-level quantifiers in the introduction rules, i.e.
  2144 
  2145       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2146 
  2147   - The format of the elimination rules is now
  2148 
  2149       p z_1 ... z_m x_1 ... x_n ==>
  2150         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2151         ==> ... ==> P
  2152 
  2153     for predicates and
  2154 
  2155       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2156         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2157         ==> ... ==> P
  2158 
  2159     for sets rather than
  2160 
  2161       x : s z_1 ... z_m ==>
  2162         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2163         ==> ... ==> P
  2164 
  2165     This may require terms in goals to be expanded to n-tuples
  2166     (e.g. using case_tac or simplification with the split_paired_all
  2167     rule) before the above elimination rule is applicable.
  2168 
  2169   - The elimination or case analysis rules for (mutually) inductive
  2170     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2171     list of rules "p_1_..._p_k.elims" is no longer available.
  2172 
  2173 * New package "function"/"fun" for general recursive functions,
  2174 supporting mutual and nested recursion, definitions in local contexts,
  2175 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2176 for small examples, and the separate tutorial on the function
  2177 package. The old recdef "package" is still available as before, but
  2178 users are encouraged to use the new package.
  2179 
  2180 * Method "lexicographic_order" automatically synthesizes termination
  2181 relations as lexicographic combinations of size measures. 
  2182 
  2183 * Case-expressions allow arbitrary constructor-patterns (including
  2184 "_") and take their order into account, like in functional
  2185 programming.  Internally, this is translated into nested
  2186 case-expressions; missing cases are added and mapped to the predefined
  2187 constant "undefined". In complicated cases printing may no longer show
  2188 the original input but the internal form. Lambda-abstractions allow
  2189 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2190 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2191 variable.
  2192 
  2193 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2194 is an abbreviation for "of_nat :: nat => int". The simplification
  2195 rules for "of_nat" have been changed to work like "int" did
  2196 previously.  Potential INCOMPATIBILITY:
  2197   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2198   - of_nat_diff and of_nat_mult are no longer default simp rules
  2199 
  2200 * Method "algebra" solves polynomial equations over (semi)rings using
  2201 Groebner bases. The (semi)ring structure is defined by locales and the
  2202 tool setup depends on that generic context. Installing the method for
  2203 a specific type involves instantiating the locale and possibly adding
  2204 declarations for computation on the coefficients.  The method is
  2205 already instantiated for natural numbers and for the axiomatic class
  2206 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2207 CALCULEMUS 2007 for the general principles underlying this
  2208 architecture of context-aware proof-tools.
  2209 
  2210 * Method "ferrack" implements quantifier elimination over
  2211 special-purpose dense linear orders using locales (analogous to
  2212 "algebra"). The method is already installed for class
  2213 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2214 rat, etc.
  2215 
  2216 * Former constant "List.op @" now named "List.append".  Use ML
  2217 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2218 circumvent possible incompatibilities when working on ML level.
  2219 
  2220 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2221 
  2222 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2223 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2224 
  2225 * New syntax for Haskell-like list comprehension (input only), eg.
  2226 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2227 
  2228 * The special syntax for function "filter" has changed from [x :
  2229 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2230 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2231 
  2232 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2233 defined on nat only, as an abbreviation for [a..<Suc b]
  2234 INCOMPATIBILITY.
  2235 
  2236 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2237 
  2238 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2239 
  2240 * New lemma collection field_simps (an extension of ring_simps) for
  2241 manipulating (in)equations involving division. Multiplies with all
  2242 denominators that can be proved to be non-zero (in equations) or
  2243 positive/negative (in inequations).
  2244 
  2245 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2246 have been improved and renamed to ring_simps, group_simps and
  2247 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2248 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2249 
  2250 * Theory Library/Commutative_Ring: switched from recdef to function
  2251 package; constants add, mul, pow now curried.  Infix syntax for
  2252 algebraic operations.
  2253 
  2254 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2255 INCOMPATIBILITY.
  2256 
  2257 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2258 INCOMPATIBILITY.
  2259 
  2260 * HOL/records: generalised field-update to take a function on the
  2261 field rather than the new value: r(|A := x|) is translated to A_update
  2262 (K x) r The K-combinator that is internally used is called K_record.
  2263 INCOMPATIBILITY: Usage of the plain update functions has to be
  2264 adapted.
  2265  
  2266 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2267 * x = 0, which are required for a semiring.  Richer structures do not
  2268 inherit from semiring_0 anymore, because this property is a theorem
  2269 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2270 there is more to prove, but this is mostly trivial.
  2271 
  2272 * Class "recpower" is generalized to arbitrary monoids, not just
  2273 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2274 commutativity or semiring properties additionally.
  2275 
  2276 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2277 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2278 better use 'abbreviation'.
  2279 
  2280 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2281 
  2282 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2283 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2284 significant changes for setting up numeral syntax for types:
  2285   - New constants Numeral.pred and Numeral.succ instead
  2286       of former Numeral.bin_pred and Numeral.bin_succ.
  2287   - Use integer operations instead of bin_add, bin_mult and so on.
  2288   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2289   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2290 
  2291 See src/HOL/Integ/IntArith.thy for an example setup.
  2292 
  2293 * Command 'normal_form' computes the normal form of a term that may
  2294 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2295 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2296 heavy-duty computations because the functions are compiled to ML
  2297 first.  Correspondingly, a method "normalization" is provided.  See
  2298 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2299 
  2300 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2301 25 like -->); output depends on the "iff" print_mode, the default is
  2302 "A = B" (with priority 50).
  2303 
  2304 * Relations less (<) and less_eq (<=) are also available on type bool.
  2305 Modified syntax to disallow nesting without explicit parentheses,
  2306 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2307 INCOMPATIBILITY.
  2308 
  2309 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2310 
  2311 * Relation composition operator "op O" now has precedence 75 and binds
  2312 stronger than union and intersection. INCOMPATIBILITY.
  2313 
  2314 * The old set interval syntax "{m..n(}" (and relatives) has been
  2315 removed.  Use "{m..<n}" (and relatives) instead.
  2316 
  2317 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2318 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2319 ``declare [[simproc del: neq]]''.
  2320 
  2321 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2322 True/False.
  2323 
  2324 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2325 
  2326 * Theorem setsum_mult renamed to setsum_right_distrib.
  2327 
  2328 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2329 ``rule'' method.
  2330 
  2331 * Reimplemented methods "sat" and "satx", with several improvements:
  2332 goals no longer need to be stated as "<prems> ==> False", equivalences
  2333 (i.e. "=" on type bool) are handled, variable names of the form
  2334 "lit_<n>" are no longer reserved, significant speedup.
  2335 
  2336 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2337 zChaff is still supported as well.
  2338 
  2339 * 'inductive' and 'datatype': provide projections of mutual rules,
  2340 bundled as foo_bar.inducts;
  2341 
  2342 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2343 Library.
  2344 
  2345 * Library: moved theory Accessible_Part to main HOL.
  2346 
  2347 * Library: added theory Coinductive_List of potentially infinite lists
  2348 as greatest fixed-point.
  2349 
  2350 * Library: added theory AssocList which implements (finite) maps as
  2351 association lists.
  2352 
  2353 * Method "evaluation" solves goals (i.e. a boolean expression)
  2354 efficiently by compiling it to ML.  The goal is "proved" (via an
  2355 oracle) if it evaluates to True.
  2356 
  2357 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2358 also when invoked by the simplifier.  This results in the Simplifier
  2359 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2360 Configuration option fast_arith_split_limit=0 recovers the old
  2361 behavior.
  2362 
  2363 * Support for hex (0x20) and binary (0b1001) numerals.
  2364 
  2365 * New method: reify eqs (t), where eqs are equations for an
  2366 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2367 parameter, computes a term s::'b and a list xs::'a list and proves the
  2368 theorem I xs s = t. This is also known as reification or quoting. The
  2369 resulting theorem is applied to the subgoal to substitute t with I xs
  2370 s.  If t is omitted, the subgoal itself is reified.
  2371 
  2372 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2373 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2374 where f is supposed to be a computable function (in the sense of code
  2375 generattion). The method uses reify to compute s and xs as above then
  2376 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2377 r and finally gets the theorem t = r, which is again applied to the
  2378 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2379 
  2380 * Reflection: Automatic reification now handels binding, an example is
  2381 available in src/HOL/ex/ReflectionEx.thy
  2382 
  2383 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2384 command 'statespace' that is similar to 'record', but introduces an
  2385 abstract specification based on the locale infrastructure instead of
  2386 HOL types.  This leads to extra flexibility in composing state spaces,
  2387 in particular multiple inheritance and renaming of components.
  2388 
  2389 
  2390 *** HOL-Complex ***
  2391 
  2392 * Hyperreal: Functions root and sqrt are now defined on negative real
  2393 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2394 Nonnegativity side conditions have been removed from many lemmas, so
  2395 that more subgoals may now be solved by simplification; potential
  2396 INCOMPATIBILITY.
  2397 
  2398 * Real: new type classes formalize real normed vector spaces and
  2399 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2400 and norm :: 'a => real.
  2401 
  2402 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2403 reals into other types. The overloaded constant Reals :: 'a set is now
  2404 defined as range of_real; potential INCOMPATIBILITY.
  2405 
  2406 * Real: proper support for ML code generation, including 'quickcheck'.
  2407 Reals are implemented as arbitrary precision rationals.
  2408 
  2409 * Hyperreal: Several constants that previously worked only for the
  2410 reals have been generalized, so they now work over arbitrary vector
  2411 spaces. Type annotations may need to be added in some cases; potential
  2412 INCOMPATIBILITY.
  2413 
  2414   Infinitesimal  :: ('a::real_normed_vector) star set
  2415   HFinite        :: ('a::real_normed_vector) star set
  2416   HInfinite      :: ('a::real_normed_vector) star set
  2417   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2418   monad          :: ('a::real_normed_vector) star => 'a star set
  2419   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2420   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2421   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2422   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2423   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2424   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2425   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2426   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2427   sgn            :: 'a::real_normed_vector => 'a
  2428   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2429 
  2430 * Complex: Some complex-specific constants are now abbreviations for
  2431 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2432 hnorm.  Other constants have been entirely removed in favor of the
  2433 polymorphic versions (INCOMPATIBILITY):
  2434 
  2435   approx        <-- capprox
  2436   HFinite       <-- CFinite
  2437   HInfinite     <-- CInfinite
  2438   Infinitesimal <-- CInfinitesimal
  2439   monad         <-- cmonad
  2440   galaxy        <-- cgalaxy
  2441   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2442   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2443   (ns)deriv     <-- (ns)cderiv
  2444 
  2445 
  2446 *** HOL-Algebra ***
  2447 
  2448 * Formalisation of ideals and the quotient construction over rings.
  2449 
  2450 * Order and lattice theory no longer based on records.
  2451 INCOMPATIBILITY.
  2452 
  2453 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2454 greatest_closed.  INCOMPATIBILITY.
  2455 
  2456 * Method algebra is now set up via an attribute.  For examples see
  2457 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2458 of algebraic structures.
  2459 
  2460 * Renamed theory CRing to Ring.
  2461 
  2462 
  2463 *** HOL-Nominal ***
  2464 
  2465 * Substantial, yet incomplete support for nominal datatypes (binding
  2466 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2467 src/HOL/Nominal/Examples.  Prospective users should consult
  2468 http://isabelle.in.tum.de/nominal/
  2469 
  2470 
  2471 *** ML ***
  2472 
  2473 * ML basics: just one true type int, which coincides with IntInf.int
  2474 (even on SML/NJ).
  2475 
  2476 * ML within Isar: antiquotations allow to embed statically-checked
  2477 formal entities in the source, referring to the context available at
  2478 compile-time.  For example:
  2479 
  2480 ML {* @{sort "{zero,one}"} *}
  2481 ML {* @{typ "'a => 'b"} *}
  2482 ML {* @{term "%x. x"} *}
  2483 ML {* @{prop "x == y"} *}
  2484 ML {* @{ctyp "'a => 'b"} *}
  2485 ML {* @{cterm "%x. x"} *}
  2486 ML {* @{cprop "x == y"} *}
  2487 ML {* @{thm asm_rl} *}
  2488 ML {* @{thms asm_rl} *}
  2489 ML {* @{type_name c} *}
  2490 ML {* @{type_syntax c} *}
  2491 ML {* @{const_name c} *}
  2492 ML {* @{const_syntax c} *}
  2493 ML {* @{context} *}
  2494 ML {* @{theory} *}
  2495 ML {* @{theory Pure} *}
  2496 ML {* @{theory_ref} *}
  2497 ML {* @{theory_ref Pure} *}
  2498 ML {* @{simpset} *}
  2499 ML {* @{claset} *}
  2500 ML {* @{clasimpset} *}
  2501 
  2502 The same works for sources being ``used'' within an Isar context.
  2503 
  2504 * ML in Isar: improved error reporting; extra verbosity with
  2505 ML_Context.trace enabled.
  2506 
  2507 * Pure/General/table.ML: the join operations now works via exceptions
  2508 DUP/SAME instead of type option. This is simpler in simple cases, and
  2509 admits slightly more efficient complex applications.
  2510 
  2511 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2512 use Context.generic instead of just theory.
  2513 
  2514 * Pure: datatype Context.generic joins theory/Proof.context and
  2515 provides some facilities for code that works in either kind of
  2516 context, notably GenericDataFun for uniform theory and proof data.
  2517 
  2518 * Pure: simplified internal attribute type, which is now always
  2519 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2520 local (Proof.context) attributes have been discontinued, while
  2521 minimizing code duplication. Thm.rule_attribute and
  2522 Thm.declaration_attribute build canonical attributes; see also structure
  2523 Context for further operations on Context.generic, notably
  2524 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2525 declarations and definitions.
  2526 
  2527 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2528 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2529 init only required for impure data. INCOMPATIBILITY: empty really need
  2530 to be empty (no dependencies on theory content!)
  2531 
  2532 * Pure/kernel: consts certification ignores sort constraints given in
  2533 signature declarations. (This information is not relevant to the
  2534 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2535 potential INCOMPATIBILITY.
  2536 
  2537 * Pure: axiomatic type classes are now purely definitional, with
  2538 explicit proofs of class axioms and super class relations performed
  2539 internally. See Pure/axclass.ML for the main internal interfaces --
  2540 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2541 AxClass.axiomatize_class/classrel/arity supersede
  2542 Sign.add_classes/classrel/arities.
  2543 
  2544 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2545 global/local versions on theory vs. Proof.context have been
  2546 discontinued; Attrib.syntax and Method.syntax have been adapted
  2547 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2548 attributes, methods, etc.
  2549 
  2550 * Pure: several functions of signature "... -> theory -> theory * ..."
  2551 have been reoriented to "... -> theory -> ... * theory" in order to
  2552 allow natural usage in combination with the ||>, ||>>, |-> and
  2553 fold_map combinators.
  2554 
  2555 * Pure: official theorem names (closed derivations) and additional
  2556 comments (tags) are now strictly separate.  Name hints -- which are
  2557 maintained as tags -- may be attached any time without affecting the
  2558 derivation.
  2559 
  2560 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2561 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2562 achieve the old behaviour.
  2563 
  2564 * Pure: the "Goal" constant is now called "prop", supporting a
  2565 slightly more general idea of ``protecting'' meta-level rule
  2566 statements.
  2567 
  2568 * Pure: Logic.(un)varify only works in a global context, which is now
  2569 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2570 Logic.legacy_(un)varify as temporary workaround.
  2571 
  2572 * Pure: structure Name provides scalable operations for generating
  2573 internal variable names, notably Name.variants etc.  This replaces
  2574 some popular functions from term.ML:
  2575 
  2576   Term.variant		->  Name.variant
  2577   Term.variantlist	->  Name.variant_list
  2578   Term.invent_names	->  Name.invent_list
  2579 
  2580 Note that low-level renaming rarely occurs in new code -- operations
  2581 from structure Variable are used instead (see below).
  2582 
  2583 * Pure: structure Variable provides fundamental operations for proper
  2584 treatment of fixed/schematic variables in a context.  For example,
  2585 Variable.import introduces fixes for schematics of given facts and
  2586 Variable.export reverses the effect (up to renaming) -- this replaces
  2587 various freeze_thaw operations.
  2588 
  2589 * Pure: structure Goal provides simple interfaces for
  2590 init/conclude/finish and tactical prove operations (replacing former
  2591 Tactic.prove).  Goal.prove is the canonical way to prove results
  2592 within a given context; Goal.prove_global is a degraded version for
  2593 theory level goals, including a global Drule.standard.  Note that
  2594 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2595 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2596 in a locale context).
  2597 
  2598 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2599 and type checking (Syntax.check_term etc.), with common combinations
  2600 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2601 which are considered legacy and await removal.
  2602 
  2603 * Pure/Syntax: generic interfaces for type unchecking
  2604 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2605 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2606 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2607 available for convenience, but refer to the very same operations using
  2608 a mere theory instead of a full context.
  2609 
  2610 * Isar: simplified treatment of user-level errors, using exception
  2611 ERROR of string uniformly.  Function error now merely raises ERROR,
  2612 without any side effect on output channels.  The Isar toplevel takes
  2613 care of proper display of ERROR exceptions.  ML code may use plain
  2614 handle/can/try; cat_error may be used to concatenate errors like this:
  2615 
  2616   ... handle ERROR msg => cat_error msg "..."
  2617 
  2618 Toplevel ML code (run directly or through the Isar toplevel) may be
  2619 embedded into the Isar toplevel with exception display/debug like
  2620 this:
  2621 
  2622   Isar.toplevel (fn () => ...)
  2623 
  2624 INCOMPATIBILITY, removed special transform_error facilities, removed
  2625 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2626 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2627 -- use plain ERROR instead.
  2628 
  2629 * Isar: theory setup now has type (theory -> theory), instead of a
  2630 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2631 
  2632 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2633 ProofContext.debug/verbose flags.
  2634 
  2635 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2636 theory before entering a proof state.  Transactions now always see a
  2637 quasi-functional intermediate checkpoint, both in interactive and
  2638 batch mode.
  2639 
  2640 * Isar: simplified interfaces for outer syntax.  Renamed
  2641 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2642 OuterSyntax.add_parsers -- this functionality is now included in
  2643 OuterSyntax.command etc.  INCOMPATIBILITY.
  2644 
  2645 * Simplifier: the simpset of a running simplification process now
  2646 contains a proof context (cf. Simplifier.the_context), which is the
  2647 very context that the initial simpset has been retrieved from (by
  2648 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2649 (solver, looper etc.) may depend on arbitrary proof data.
  2650 
  2651 * Simplifier.inherit_context inherits the proof context (plus the
  2652 local bounds) of the current simplification process; any simproc
  2653 etc. that calls the Simplifier recursively should do this!  Removed
  2654 former Simplifier.inherit_bounds, which is already included here --
  2655 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2656 specify an explicit context using Simplifier.context/theory_context.
  2657 
  2658 * Simplifier/Classical Reasoner: more abstract interfaces
  2659 change_simpset/claset for modifying the simpset/claset reference of a
  2660 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2661 INCOMPATIBILITY.
  2662 
  2663 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2664 "Trueprop" etc.
  2665 
  2666 
  2667 *** System ***
  2668 
  2669 * settings: the default heap location within ISABELLE_HOME_USER now
  2670 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2671 Isabelle installations.
  2672 
  2673 * isabelle-process: option -S (secure mode) disables some critical
  2674 operations, notably runtime compilation and evaluation of ML source
  2675 code.
  2676 
  2677 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2678 
  2679 * Support for parallel execution, using native multicore support of
  2680 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2681 independent theories, according to the given theory header
  2682 specifications. The maximum number of worker threads is specified via
  2683 usedir option -M or the "max-threads" setting in Proof General. A
  2684 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2685 to 6 on a 8-core machine.  User-code needs to observe certain
  2686 guidelines for thread-safe programming, see appendix A in the Isar
  2687 Implementation manual.
  2688 
  2689 
  2690 
  2691 New in Isabelle2005 (October 2005)
  2692 ----------------------------------
  2693 
  2694 *** General ***
  2695 
  2696 * Theory headers: the new header syntax for Isar theories is
  2697 
  2698   theory <name>
  2699   imports <theory1> ... <theoryN>
  2700   uses <file1> ... <fileM>
  2701   begin
  2702 
  2703 where the 'uses' part is optional.  The previous syntax
  2704 
  2705   theory <name> = <theory1> + ... + <theoryN>:
  2706 
  2707 will disappear in the next release.  Use isatool fixheaders to convert
  2708 existing theory files.  Note that there is no change in ancient
  2709 non-Isar theories now, but these will disappear soon.
  2710 
  2711 * Theory loader: parent theories can now also be referred to via
  2712 relative and absolute paths.
  2713 
  2714 * Command 'find_theorems' searches for a list of criteria instead of a
  2715 list of constants. Known criteria are: intro, elim, dest, name:string,
  2716 simp:term, and any term. Criteria can be preceded by '-' to select
  2717 theorems that do not match. Intro, elim, dest select theorems that
  2718 match the current goal, name:s selects theorems whose fully qualified
  2719 name contain s, and simp:term selects all simplification rules whose
  2720 lhs match term.  Any other term is interpreted as pattern and selects
  2721 all theorems matching the pattern. Available in ProofGeneral under
  2722 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2723 
  2724   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2725 
  2726 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2727 matching the current goal as introduction rule and not having "HOL."
  2728 in their name (i.e. not being defined in theory HOL).
  2729 
  2730 * Command 'thms_containing' has been discontinued in favour of
  2731 'find_theorems'; INCOMPATIBILITY.
  2732 
  2733 * Communication with Proof General is now 8bit clean, which means that
  2734 Unicode text in UTF-8 encoding may be used within theory texts (both
  2735 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2736 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2737 
  2738   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2739   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2740 
  2741 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2742 Classical Reasoner.  Typical big applications run around 2 times
  2743 faster.
  2744 
  2745 
  2746 *** Document preparation ***
  2747 
  2748 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2749 of raw sources.  Only those symbols that do not require additional
  2750 LaTeX packages (depending on comments in isabellesym.sty) are
  2751 displayed properly, everything else is left verbatim.  isatool display
  2752 and isatool print are used as front ends (these are subject to the
  2753 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2754 
  2755 * Command tags control specific markup of certain regions of text,
  2756 notably folding and hiding.  Predefined tags include "theory" (for
  2757 theory begin and end), "proof" for proof commands, and "ML" for
  2758 commands involving ML code; the additional tags "visible" and
  2759 "invisible" are unused by default.  Users may give explicit tag
  2760 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2761 interpretation of tags is determined by the LaTeX job during document
  2762 preparation: see option -V of isatool usedir, or options -n and -t of
  2763 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2764 \isadroptag.
  2765 
  2766 Several document versions may be produced at the same time via isatool
  2767 usedir (the generated index.html will link all of them).  Typical
  2768 specifications include ''-V document=theory,proof,ML'' to present
  2769 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2770 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2771 these parts without any formal replacement text.  The Isabelle site
  2772 default settings produce ''document'' and ''outline'' versions as
  2773 specified above.
  2774 
  2775 * Several new antiquotations:
  2776 
  2777   @{term_type term} prints a term with its type annotated;
  2778 
  2779   @{typeof term} prints the type of a term;
  2780 
  2781   @{const const} is the same as @{term const}, but checks that the
  2782   argument is a known logical constant;
  2783 
  2784   @{term_style style term} and @{thm_style style thm} print a term or
  2785   theorem applying a "style" to it
  2786 
  2787   @{ML text}
  2788 
  2789 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2790 definitions, equations, inequations etc., 'concl' printing only the
  2791 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2792 to print the specified premise.  TermStyle.add_style provides an ML
  2793 interface for introducing further styles.  See also the "LaTeX Sugar"
  2794 document practical applications.  The ML antiquotation prints
  2795 type-checked ML expressions verbatim.
  2796 
  2797 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2798 and 'text' support optional locale specification '(in loc)', which
  2799 specifies the default context for interpreting antiquotations.  For
  2800 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2801 
  2802 * Option 'locale=NAME' of antiquotations specifies an alternative
  2803 context interpreting the subsequent argument.  For example: @{thm
  2804 [locale=lattice] inf_assoc}.
  2805 
  2806 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2807 a proof context.
  2808 
  2809 * Proper output of antiquotations for theory commands involving a
  2810 proof context (such as 'locale' or 'theorem (in loc) ...').
  2811 
  2812 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2813 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2814 
  2815 * isatool usedir: new option -C (default true) controls whether option
  2816 -D should include a copy of the original document directory; -C false
  2817 prevents unwanted effects such as copying of administrative CVS data.
  2818 
  2819 
  2820 *** Pure ***
  2821 
  2822 * Considerably improved version of 'constdefs' command.  Now performs
  2823 automatic type-inference of declared constants; additional support for
  2824 local structure declarations (cf. locales and HOL records), see also
  2825 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2826 sequential dependencies of definitions within a single 'constdefs'
  2827 section; moreover, the declared name needs to be an identifier.  If
  2828 all fails, consider to fall back on 'consts' and 'defs' separately.
  2829 
  2830 * Improved indexed syntax and implicit structures.  First of all,
  2831 indexed syntax provides a notational device for subscripted
  2832 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2833 expressions.  Secondly, in a local context with structure
  2834 declarations, number indexes \<^sub>n or the empty index (default
  2835 number 1) refer to a certain fixed variable implicitly; option
  2836 show_structs controls printing of implicit structures.  Typical
  2837 applications of these concepts involve record types and locales.
  2838 
  2839 * New command 'no_syntax' removes grammar declarations (and
  2840 translations) resulting from the given syntax specification, which is
  2841 interpreted in the same manner as for the 'syntax' command.
  2842 
  2843 * 'Advanced' translation functions (parse_translation etc.) may depend
  2844 on the signature of the theory context being presently used for
  2845 parsing/printing, see also isar-ref manual.
  2846 
  2847 * Improved 'oracle' command provides a type-safe interface to turn an
  2848 ML expression of type theory -> T -> term into a primitive rule of
  2849 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2850 is already included here); see also FOL/ex/IffExample.thy;
  2851 INCOMPATIBILITY.
  2852 
  2853 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2854 before); "cI" is no longer bound, use "c.intro" instead.
  2855 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2856 axclasses vs. locales.
  2857 
  2858 * Improved internal renaming of symbolic identifiers -- attach primes
  2859 instead of base 26 numbers.
  2860 
  2861 * New flag show_question_marks controls printing of leading question
  2862 marks in schematic variable names.
  2863 
  2864 * In schematic variable names, *any* symbol following \<^isub> or
  2865 \<^isup> is now treated as part of the base name.  For example, the
  2866 following works without printing of awkward ".0" indexes:
  2867 
  2868   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2869     by simp
  2870 
  2871 * Inner syntax includes (*(*nested*) comments*).
  2872 
  2873 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2874 annotations as "(00...)".
  2875 
  2876 * Clear separation of logical types and nonterminals, where the latter
  2877 may only occur in 'syntax' specifications or type abbreviations.
  2878 Before that distinction was only partially implemented via type class
  2879 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2880 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2881 exotic syntax specifications may require further adaption
  2882 (e.g. Cube/Cube.thy).
  2883 
  2884 * Removed obsolete type class "logic", use the top sort {} instead.
  2885 Note that non-logical types should be declared as 'nonterminals'
  2886 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2887 specifications.
  2888 
  2889 * Attributes 'induct' and 'cases': type or set names may now be
  2890 locally fixed variables as well.
  2891 
  2892 * Simplifier: can now control the depth to which conditional rewriting
  2893 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2894 Limit.
  2895 
  2896 * Simplifier: simplification procedures may now take the current
  2897 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2898 interface), which is very useful for calling the Simplifier
  2899 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2900 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2901 low-level mk_simproc no longer applies Logic.varify internally, to
  2902 allow for use in a context of fixed variables.
  2903 
  2904 * thin_tac now works even if the assumption being deleted contains !!
  2905 or ==>.  More generally, erule now works even if the major premise of
  2906 the elimination rule contains !! or ==>.
  2907 
  2908 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2909 
  2910 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2911 from Pure, which contains all common declarations already.  Both
  2912 theories are defined via plain Isabelle/Isar .thy files.
  2913 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2914 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2915 use isatool fixcpure to adapt your theory and ML sources.
  2916 
  2917 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2918 selections of theorems in named facts via index ranges.
  2919 
  2920 * 'print_theorems': in theory mode, really print the difference
  2921 wrt. the last state (works for interactive theory development only),
  2922 in proof mode print all local facts (cf. 'print_facts');
  2923 
  2924 * 'hide': option '(open)' hides only base names.
  2925 
  2926 * More efficient treatment of intermediate checkpoints in interactive
  2927 theory development.
  2928 
  2929 * Code generator is now invoked via code_module (incremental code
  2930 generation) and code_library (modular code generation, ML structures
  2931 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2932 must be quoted when used as identifiers.
  2933 
  2934 * New 'value' command for reading, evaluating and printing terms using
  2935 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2936 quoted when used as identifier.
  2937 
  2938 
  2939 *** Locales ***
  2940 
  2941 * New commands for the interpretation of locale expressions in
  2942 theories (1), locales (2) and proof contexts (3).  These generate
  2943 proof obligations from the expression specification.  After the
  2944 obligations have been discharged, theorems of the expression are added
  2945 to the theory, target locale or proof context.  The synopsis of the
  2946 commands is a follows:
  2947 
  2948   (1) interpretation expr inst
  2949   (2) interpretation target < expr
  2950   (3) interpret expr inst
  2951 
  2952 Interpretation in theories and proof contexts require a parameter
  2953 instantiation of terms from the current context.  This is applied to
  2954 specifications and theorems of the interpreted expression.
  2955 Interpretation in locales only permits parameter renaming through the
  2956 locale expression.  Interpretation is smart in that interpretations
  2957 that are active already do not occur in proof obligations, neither are
  2958 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2959 inspect active interpretations of a particular locale.  For details,
  2960 see the Isar Reference manual.  Examples can be found in
  2961 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2962 
  2963 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2964 'interpret' instead.
  2965 
  2966 * New context element 'constrains' for adding type constraints to
  2967 parameters.
  2968 
  2969 * Context expressions: renaming of parameters with syntax
  2970 redeclaration.
  2971 
  2972 * Locale declaration: 'includes' disallowed.
  2973 
  2974 * Proper static binding of attribute syntax -- i.e. types / terms /
  2975 facts mentioned as arguments are always those of the locale definition
  2976 context, independently of the context of later invocations.  Moreover,
  2977 locale operations (renaming and type / term instantiation) are applied
  2978 to attribute arguments as expected.
  2979 
  2980 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2981 actual attributes; rare situations may require Attrib.attribute to
  2982 embed those attributes into Attrib.src that lack concrete syntax.
  2983 Attribute implementations need to cooperate properly with the static
  2984 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2985 Attrib.XXX_thm etc. already do the right thing without further
  2986 intervention.  Only unusual applications -- such as "where" or "of"
  2987 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2988 on the context and the facts involved -- may have to assign parsed
  2989 values to argument tokens explicitly.
  2990 
  2991 * Changed parameter management in theorem generation for long goal
  2992 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2993 theorem statement in rare situations.
  2994 
  2995 * Locale inspection command 'print_locale' omits notes elements.  Use
  2996 'print_locale!' to have them included in the output.
  2997 
  2998 
  2999 *** Provers ***
  3000 
  3001 * Provers/hypsubst.ML: improved version of the subst method, for
  3002 single-step rewriting: it now works in bound variable contexts. New is
  3003 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  3004 rewrite a different subterm than the original subst method, which is
  3005 still available as 'simplesubst'.
  3006 
  3007 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  3008 and quasi orders.
  3009 
  3010 * Provers/trancl.ML: new transitivity reasoner for transitive and
  3011 reflexive-transitive closure of relations.
  3012 
  3013 * Provers/blast.ML: new reference depth_limit to make blast's depth
  3014 limit (previously hard-coded with a value of 20) user-definable.
  3015 
  3016 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  3017 is peformed already.  Object-logics merely need to finish their
  3018 initial simpset configuration as before.  INCOMPATIBILITY.
  3019 
  3020 
  3021 *** HOL ***
  3022 
  3023 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3024 
  3025   syntax (epsilon)
  3026     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3027 
  3028 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3029 and x-symbol; use option '-m epsilon' to get it actually printed.
  3030 Moreover, the mathematically important symbolic identifier \<epsilon>
  3031 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3032 
  3033 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3034 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3035 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3036 support corresponding Isar calculations.
  3037 
  3038 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3039 instead of ":".
  3040 
  3041 * theory SetInterval: changed the syntax for open intervals:
  3042 
  3043   Old       New
  3044   {..n(}    {..<n}
  3045   {)n..}    {n<..}
  3046   {m..n(}   {m..<n}
  3047   {)m..n}   {m<..n}
  3048   {)m..n(}  {m<..<n}
  3049 
  3050 The old syntax is still supported but will disappear in the next
  3051 release.  For conversion use the following Emacs search and replace
  3052 patterns (these are not perfect but work quite well):
  3053 
  3054   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3055   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3056 
  3057 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3058 equalities in commutative rings; method 'algebra' provides a generic
  3059 interface.
  3060 
  3061 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3062 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3063 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3064 be a tuple pattern.
  3065 
  3066 Some new syntax forms are available:
  3067 
  3068   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3069   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3070   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3071   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3072 
  3073 The latter form "\<Sum>x < k. e" used to be based on a separate
  3074 function "Summation", which has been discontinued.
  3075 
  3076 * theory Finite_Set: in structured induction proofs, the insert case
  3077 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3078 (insert F x)'.
  3079 
  3080 * The 'refute' command has been extended to support a much larger
  3081 fragment of HOL, including axiomatic type classes, constdefs and
  3082 typedefs, inductive datatypes and recursion.
  3083 
  3084 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3085 Requires zChaff with proof generation to be installed.  See
  3086 HOL/ex/SAT_Examples.thy for examples.
  3087 
  3088 * Datatype induction via method 'induct' now preserves the name of the
  3089 induction variable. For example, when proving P(xs::'a list) by
  3090 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3091 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3092 in unstructured proof scripts.
  3093 
  3094 * Reworked implementation of records.  Improved scalability for
  3095 records with many fields, avoiding performance problems for type
  3096 inference. Records are no longer composed of nested field types, but
  3097 of nested extension types. Therefore the record type only grows linear
  3098 in the number of extensions and not in the number of fields.  The
  3099 top-level (users) view on records is preserved.  Potential
  3100 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3101 old record representation. The type generated for a record is called
  3102 <record_name>_ext_type.
  3103 
  3104 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3105 proofs triggered by a record definition or a simproc (if
  3106 quick_and_dirty is enabled).  Definitions of large records can take
  3107 quite long.
  3108 
  3109 New simproc record_upd_simproc for simplification of multiple record
  3110 updates enabled by default.  Moreover, trivial updates are also
  3111 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3112 occasionally, since simplification is more powerful by default.
  3113 
  3114 * typedef: proper support for polymorphic sets, which contain extra
  3115 type-variables in the term.
  3116 
  3117 * Simplifier: automatically reasons about transitivity chains
  3118 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3119 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3120 old proofs break occasionally as simplification may now solve more
  3121 goals than previously.
  3122 
  3123 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3124 present.  Works for all partial orders (class "order"), in particular
  3125 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3126 just like y <= x.
  3127 
  3128 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3129 bound variable or a constant then the let is unfolded.  Otherwise
  3130 first a is simplified to b, and then f b is simplified to g. If
  3131 possible we abstract b from g arriving at "let x = b in h x",
  3132 otherwise we unfold the let and arrive at g.  The simproc can be
  3133 enabled/disabled by the reference use_let_simproc.  Potential
  3134 INCOMPATIBILITY since simplification is more powerful by default.
  3135 
  3136 * Classical reasoning: the meson method now accepts theorems as arguments.
  3137 
  3138 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3139 jobs to provide advice on the provability of subgoals.
  3140 
  3141 * Theory OrderedGroup and Ring_and_Field: various additions and
  3142 improvements to faciliate calculations involving equalities and
  3143 inequalities.
  3144 
  3145 The following theorems have been eliminated or modified
  3146 (INCOMPATIBILITY):
  3147 
  3148   abs_eq             now named abs_of_nonneg
  3149   abs_of_ge_0        now named abs_of_nonneg
  3150   abs_minus_eq       now named abs_of_nonpos
  3151   imp_abs_id         now named abs_of_nonneg
  3152   imp_abs_neg_id     now named abs_of_nonpos
  3153   mult_pos           now named mult_pos_pos
  3154   mult_pos_le        now named mult_nonneg_nonneg
  3155   mult_pos_neg_le    now named mult_nonneg_nonpos
  3156   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3157   mult_neg           now named mult_neg_neg
  3158   mult_neg_le        now named mult_nonpos_nonpos
  3159 
  3160 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3161      
  3162      zero_le_square
  3163      not_square_less_zero 
  3164 
  3165   The following lemmas have been deleted from Real/RealPow:
  3166   
  3167      realpow_zero_zero
  3168      realpow_two
  3169      realpow_less
  3170      zero_le_power
  3171      realpow_two_le
  3172      abs_realpow_two
  3173      realpow_two_abs     
  3174 
  3175 * Theory Parity: added rules for simplifying exponents.
  3176 
  3177 * Theory List:
  3178 
  3179 The following theorems have been eliminated or modified
  3180 (INCOMPATIBILITY):
  3181 
  3182   list_all_Nil       now named list_all.simps(1)
  3183   list_all_Cons      now named list_all.simps(2)
  3184   list_all_conv      now named list_all_iff
  3185   set_mem_eq         now named mem_iff
  3186 
  3187 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3188 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3189 
  3190 
  3191 *** HOL-Complex ***
  3192 
  3193 * Theory RealDef: better support for embedding natural numbers and
  3194 integers in the reals.
  3195 
  3196 The following theorems have been eliminated or modified
  3197 (INCOMPATIBILITY):
  3198 
  3199   exp_ge_add_one_self  now requires no hypotheses
  3200   real_of_int_add      reversed direction of equality (use [symmetric])
  3201   real_of_int_minus    reversed direction of equality (use [symmetric])
  3202   real_of_int_diff     reversed direction of equality (use [symmetric])
  3203   real_of_int_mult     reversed direction of equality (use [symmetric])
  3204 
  3205 * Theory RComplete: expanded support for floor and ceiling functions.
  3206 
  3207 * Theory Ln is new, with properties of the natural logarithm
  3208 
  3209 * Hyperreal: There is a new type constructor "star" for making
  3210 nonstandard types.  The old type names are now type synonyms:
  3211 
  3212   hypreal = real star
  3213   hypnat = nat star
  3214   hcomplex = complex star
  3215 
  3216 * Hyperreal: Many groups of similarly-defined constants have been
  3217 replaced by polymorphic versions (INCOMPATIBILITY):
  3218 
  3219   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3220 
  3221   starset      <-- starsetNat, starsetC
  3222   *s*          <-- *sNat*, *sc*
  3223   starset_n    <-- starsetNat_n, starsetC_n
  3224   *sn*         <-- *sNatn*, *scn*
  3225   InternalSets <-- InternalNatSets, InternalCSets
  3226 
  3227   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3228   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3229   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3230   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3231   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3232 
  3233 * Hyperreal: Many type-specific theorems have been removed in favor of
  3234 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3235 
  3236   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3237   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3238   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3239   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3240   right_minus <-- hypreal_add_minus
  3241   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3242   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3243   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3244   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3245   mult_1_right <-- hcomplex_mult_one_right
  3246   mult_zero_left <-- hcomplex_mult_zero_left
  3247   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3248   right_distrib <-- hypnat_add_mult_distrib2
  3249   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3250   right_inverse <-- hypreal_mult_inverse
  3251   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3252   order_refl <-- {hypreal,hypnat}_le_refl
  3253   order_trans <-- {hypreal,hypnat}_le_trans
  3254   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3255   order_less_le <-- {hypreal,hypnat}_less_le
  3256   linorder_linear <-- {hypreal,hypnat}_le_linear
  3257   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3258   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3259   add_nonneg_nonneg <-- hypreal_le_add_order
  3260 
  3261 * Hyperreal: Separate theorems having to do with type-specific
  3262 versions of constants have been merged into theorems that apply to the
  3263 new polymorphic constants (INCOMPATIBILITY):
  3264 
  3265   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3266   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3267   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3268   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3269   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3270   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3271   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3272   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3273   STAR_diff <-- {STAR,STARC}_diff
  3274   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3275     STARC_hcomplex_of_complex}_image_subset
  3276   starset_n_Un <-- starset{Nat,C}_n_Un
  3277   starset_n_Int <-- starset{Nat,C}_n_Int
  3278   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3279   starset_n_diff <-- starset{Nat,C}_n_diff
  3280   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3281   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3282   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3283   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3284   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3285   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3286   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3287   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3288   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3289   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3290   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3291   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3292   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3293   starfun_diff <-- starfun{C,RC,CR}_diff
  3294   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3295   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3296   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3297   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3298   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3299   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3300   starfun_Id <-- starfunC_Id
  3301   starfun_approx <-- starfun{Nat,CR}_approx
  3302   starfun_capprox <-- starfun{C,RC}_capprox
  3303   starfun_abs <-- starfunNat_rabs
  3304   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3305   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3306   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3307   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3308   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3309   starfun_add_approx <-- starfunCR_add_approx
  3310   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3311   starfun_divide <-- starfun{C,CR,RC}_divide
  3312   starfun_n <-- starfun{Nat,C}_n
  3313   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3314   starfun_n_add <-- starfun{Nat,C}_n_add
  3315   starfun_n_add_minus <-- starfunNat_n_add_minus
  3316   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3317   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3318   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3319 
  3320   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3321   star_n_minus <-- {hypreal,hcomplex}_minus
  3322   star_n_diff <-- {hypreal,hcomplex}_diff
  3323   star_n_mult <-- {hypreal,hcomplex}_mult
  3324   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3325   star_n_le <-- {hypreal,hypnat}_le
  3326   star_n_less <-- {hypreal,hypnat}_less
  3327   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3328   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3329   star_n_abs <-- hypreal_hrabs
  3330   star_n_divide <-- hcomplex_divide
  3331 
  3332   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3333   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3334   star_of_diff <-- hypreal_of_real_diff
  3335   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3336   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3337   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3338   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3339   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3340   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3341   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3342   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3343   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3344   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3345   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3346   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3347   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3348   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3349   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3350   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3351   star_of_power <-- hypreal_of_real_power
  3352   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3353 
  3354 * Hyperreal: new method "transfer" that implements the transfer
  3355 principle of nonstandard analysis. With a subgoal that mentions
  3356 nonstandard types like "'a star", the command "apply transfer"
  3357 replaces it with an equivalent one that mentions only standard types.
  3358 To be successful, all free variables must have standard types; non-
  3359 standard variables must have explicit universal quantifiers.
  3360 
  3361 * Hyperreal: A theory of Taylor series.
  3362 
  3363 
  3364 *** HOLCF ***
  3365 
  3366 * Discontinued special version of 'constdefs' (which used to support
  3367 continuous functions) in favor of the general Pure one with full
  3368 type-inference.
  3369 
  3370 * New simplification procedure for solving continuity conditions; it
  3371 is much faster on terms with many nested lambda abstractions (cubic
  3372 instead of exponential time).
  3373 
  3374 * New syntax for domain package: selector names are now optional.
  3375 Parentheses should be omitted unless argument is lazy, for example:
  3376 
  3377   domain 'a stream = cons "'a" (lazy "'a stream")
  3378 
  3379 * New command 'fixrec' for defining recursive functions with pattern
  3380 matching; defining multiple functions with mutual recursion is also
  3381 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3382 sinr, or any data constructor defined by the domain package. The given
  3383 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3384 syntax and examples.
  3385 
  3386 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3387 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3388 but the proof obligation additionally includes an admissibility
  3389 requirement. The packages generate instances of class cpo or pcpo,
  3390 with continuity and strictness theorems for Rep and Abs.
  3391 
  3392 * HOLCF: Many theorems have been renamed according to a more standard naming
  3393 scheme (INCOMPATIBILITY):
  3394 
  3395   foo_inject:  "foo$x = foo$y ==> x = y"
  3396   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3397   foo_less:    "(foo$x << foo$y) = (x << y)"
  3398   foo_strict:  "foo$UU = UU"
  3399   foo_defined: "... ==> foo$x ~= UU"
  3400   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3401 
  3402 
  3403 *** ZF ***
  3404 
  3405 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3406 including the First Isomorphism Theorem (on quotienting by the kernel
  3407 of a homomorphism).
  3408 
  3409 * ZF/Simplifier: install second copy of type solver that actually
  3410 makes use of TC rules declared to Isar proof contexts (or locales);
  3411 the old version is still required for ML proof scripts.
  3412 
  3413 
  3414 *** Cube ***
  3415 
  3416 * Converted to Isar theory format; use locales instead of axiomatic
  3417 theories.
  3418 
  3419 
  3420 *** ML ***
  3421 
  3422 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3423 for ||>, ||>>, |>>,
  3424 
  3425 * Pure/library.ML no longer defines its own option datatype, but uses
  3426 that of the SML basis, which has constructors NONE and SOME instead of
  3427 None and Some, as well as exception Option.Option instead of OPTION.
  3428 The functions the, if_none, is_some, is_none have been adapted
  3429 accordingly, while Option.map replaces apsome.
  3430 
  3431 * Pure/library.ML: the exception LIST has been given up in favour of
  3432 the standard exceptions Empty and Subscript, as well as
  3433 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3434 superceded by the standard hd and tl functions etc.
  3435 
  3436 A number of basic list functions are no longer exported to the ML
  3437 toplevel, as they are variants of predefined functions.  The following
  3438 suggests how one can translate existing code:
  3439 
  3440     rev_append xs ys = List.revAppend (xs, ys)
  3441     nth_elem (i, xs) = List.nth (xs, i)
  3442     last_elem xs = List.last xs
  3443     flat xss = List.concat xss
  3444     seq fs = List.app fs
  3445     partition P xs = List.partition P xs
  3446     mapfilter f xs = List.mapPartial f xs
  3447 
  3448 * Pure/library.ML: several combinators for linear functional
  3449 transformations, notably reverse application and composition:
  3450 
  3451   x |> f                f #> g
  3452   (x, y) |-> f          f #-> g
  3453 
  3454 * Pure/library.ML: introduced/changed precedence of infix operators:
  3455 
  3456   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3457   infix 2 ?;
  3458   infix 3 o oo ooo oooo;
  3459   infix 4 ~~ upto downto;
  3460 
  3461 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3462 infix operators.
  3463 
  3464 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3465 fold_map support linear functional transformations and nesting.  For
  3466 example:
  3467 
  3468   fold f [x1, ..., xN] y =
  3469     y |> f x1 |> ... |> f xN
  3470 
  3471   (fold o fold) f [xs1, ..., xsN] y =
  3472     y |> fold f xs1 |> ... |> fold f xsN
  3473 
  3474   fold f [x1, ..., xN] =
  3475     f x1 #> ... #> f xN
  3476 
  3477   (fold o fold) f [xs1, ..., xsN] =
  3478     fold f xs1 #> ... #> fold f xsN
  3479 
  3480 * Pure/library.ML: the following selectors on type 'a option are
  3481 available:
  3482 
  3483   the:               'a option -> 'a  (*partial*)
  3484   these:             'a option -> 'a  where 'a = 'b list
  3485   the_default: 'a -> 'a option -> 'a
  3486   the_list:          'a option -> 'a list
  3487 
  3488 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3489 basic operations for association lists, following natural argument
  3490 order; moreover the explicit equality predicate passed here avoids
  3491 potentially expensive polymorphic runtime equality checks.
  3492 The old functions may be expressed as follows:
  3493 
  3494   assoc = uncurry (AList.lookup (op =))
  3495   assocs = these oo AList.lookup (op =)
  3496   overwrite = uncurry (AList.update (op =)) o swap
  3497 
  3498 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3499 
  3500   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3501   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3502 
  3503 replacing make_keylist and keyfilter (occassionally used)
  3504 Naive rewrites:
  3505 
  3506   make_keylist = AList.make
  3507   keyfilter = AList.find (op =)
  3508 
  3509 * eq_fst and eq_snd now take explicit equality parameter, thus
  3510   avoiding eqtypes. Naive rewrites:
  3511 
  3512     eq_fst = eq_fst (op =)
  3513     eq_snd = eq_snd (op =)
  3514 
  3515 * Removed deprecated apl and apr (rarely used).
  3516   Naive rewrites:
  3517 
  3518     apl (n, op) =>>= curry op n
  3519     apr (op, m) =>>= fn n => op (n, m)
  3520 
  3521 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3522 provides a reasonably efficient light-weight implementation of sets as
  3523 lists.
  3524 
  3525 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3526 few new operations; existing lookup and update are now curried to
  3527 follow natural argument order (for use with fold etc.);
  3528 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3529 
  3530 * Pure/General: output via the Isabelle channels of
  3531 writeln/warning/error etc. is now passed through Output.output, with a
  3532 hook for arbitrary transformations depending on the print_mode
  3533 (cf. Output.add_mode -- the first active mode that provides a output
  3534 function wins).  Already formatted output may be embedded into further
  3535 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3536 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3537 accommodate easy composition of diagnostic messages etc.  Programmers
  3538 rarely need to care about Output.output or Output.raw at all, with
  3539 some notable exceptions: Output.output is required when bypassing the
  3540 standard channels (writeln etc.), or in token translations to produce
  3541 properly formatted results; Output.raw is required when capturing
  3542 already output material that will eventually be presented to the user
  3543 a second time.  For the default print mode, both Output.output and
  3544 Output.raw have no effect.
  3545 
  3546 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3547 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3548 cumulative results are displayed at the end of a batch session.
  3549 
  3550 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3551 replaced by File.platform_path and File.shell_path (with appropriate
  3552 hooks).  This provides a clean interface for unusual systems where the
  3553 internal and external process view of file names are different.
  3554 
  3555 * Pure: more efficient orders for basic syntactic entities: added
  3556 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3557 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3558 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3559 orders now -- potential INCOMPATIBILITY for code that depends on a
  3560 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3561 Library.sort_strings on result).
  3562 
  3563 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3564 fold_types traverse types/terms from left to right, observing natural
  3565 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3566 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3567 
  3568 * Pure: name spaces have been refined, with significant changes of the
  3569 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3570 to extern(_table).  The plain name entry path is superceded by a
  3571 general 'naming' context, which also includes the 'policy' to produce
  3572 a fully qualified name and external accesses of a fully qualified
  3573 name; NameSpace.extend is superceded by context dependent
  3574 Sign.declare_name.  Several theory and proof context operations modify
  3575 the naming context.  Especially note Theory.restore_naming and
  3576 ProofContext.restore_naming to get back to a sane state; note that
  3577 Theory.add_path is no longer sufficient to recover from
  3578 Theory.absolute_path in particular.
  3579 
  3580 * Pure: new flags short_names (default false) and unique_names
  3581 (default true) for controlling output of qualified names.  If
  3582 short_names is set, names are printed unqualified.  If unique_names is
  3583 reset, the name prefix is reduced to the minimum required to achieve
  3584 the original result when interning again, even if there is an overlap
  3585 with earlier declarations.
  3586 
  3587 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3588 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3589 (useful for printing error messages).  INCOMPATIBILITY.
  3590 
  3591 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3592 Theory.theory are now identified, referring to the universal
  3593 Context.theory (see Pure/context.ML).  Actual signature and theory
  3594 content is managed as theory data.  The old code and interfaces were
  3595 spread over many files and structures; the new arrangement introduces
  3596 considerable INCOMPATIBILITY to gain more clarity:
  3597 
  3598   Context -- theory management operations (name, identity, inclusion,
  3599     parents, ancestors, merge, etc.), plus generic theory data;
  3600 
  3601   Sign -- logical signature and syntax operations (declaring consts,
  3602     types, etc.), plus certify/read for common entities;
  3603 
  3604   Theory -- logical theory operations (stating axioms, definitions,
  3605     oracles), plus a copy of logical signature operations (consts,
  3606     types, etc.); also a few basic management operations (Theory.copy,
  3607     Theory.merge, etc.)
  3608 
  3609 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3610 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3611 for convenience -- they merely return the theory.
  3612 
  3613 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3614 
  3615 * Pure: the Isar proof context type is already defined early in Pure
  3616 as Context.proof (note that ProofContext.context and Proof.context are
  3617 aliases, where the latter is the preferred name).  This enables other
  3618 Isabelle components to refer to that type even before Isar is present.
  3619 
  3620 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3621 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3622 any of these kinds.  For example, Sign.intern typeK is now
  3623 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3624 Theory.hide_types.  Also note that former
  3625 Theory.hide_classes/types/consts are now
  3626 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3627 internalize their arguments!  INCOMPATIBILITY.
  3628 
  3629 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3630 datatype thmref (with constructors Name and NameSelection) instead of
  3631 plain string -- INCOMPATIBILITY;
  3632 
  3633 * Pure: cases produced by proof methods specify options, where NONE
  3634 means to remove case bindings -- INCOMPATIBILITY in
  3635 (RAW_)METHOD_CASES.
  3636 
  3637 * Pure: the following operations retrieve axioms or theorems from a
  3638 theory node or theory hierarchy, respectively:
  3639 
  3640   Theory.axioms_of: theory -> (string * term) list
  3641   Theory.all_axioms_of: theory -> (string * term) list
  3642   PureThy.thms_of: theory -> (string * thm) list
  3643   PureThy.all_thms_of: theory -> (string * thm) list
  3644 
  3645 * Pure: print_tac now outputs the goal through the trace channel.
  3646 
  3647 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3648 Reference Toplevel.debug (default false) controls detailed printing
  3649 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3650 controls execution profiling -- set to 1 for time and 2 for space
  3651 (both increase the runtime).
  3652 
  3653 * Isar session: The initial use of ROOT.ML is now always timed,
  3654 i.e. the log will show the actual process times, in contrast to the
  3655 elapsed wall-clock time that the outer shell wrapper produces.
  3656 
  3657 * Simplifier: improved handling of bound variables (nameless
  3658 representation, avoid allocating new strings).  Simprocs that invoke
  3659 the Simplifier recursively should use Simplifier.inherit_bounds to
  3660 avoid local name clashes.  Failure to do so produces warnings
  3661 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3662 for further details.
  3663 
  3664 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3665 bindings for all theorems stored within a given theory; this may help
  3666 in porting non-Isar theories to Isar ones, while keeping ML proof
  3667 scripts for the time being.
  3668 
  3669 * ML operator HTML.with_charset specifies the charset begin used for
  3670 generated HTML files.  For example:
  3671 
  3672   HTML.with_charset "utf-8" use_thy "Hebrew";
  3673   HTML.with_charset "utf-8" use_thy "Chinese";
  3674 
  3675 
  3676 *** System ***
  3677 
  3678 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3679 isabelle, isatool etc.).
  3680 
  3681 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3682 isatool doc, isatool mkdir, display_drafts etc.).
  3683 
  3684 * isatool usedir: option -f allows specification of the ML file to be
  3685 used by Isabelle; default is ROOT.ML.
  3686 
  3687 * New isatool version outputs the version identifier of the Isabelle
  3688 distribution being used.
  3689 
  3690 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3691 (containing Boolean satisfiability problems) into Isabelle/HOL
  3692 theories.
  3693 
  3694 
  3695 
  3696 New in Isabelle2004 (April 2004)
  3697 --------------------------------
  3698 
  3699 *** General ***
  3700 
  3701 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3702   Replaces linorder.ML.
  3703 
  3704 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3705   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3706   (\<a>...\<z>), are now considered normal letters, and can therefore
  3707   be used anywhere where an ASCII letter (a...zA...Z) has until
  3708   now. COMPATIBILITY: This obviously changes the parsing of some
  3709   terms, especially where a symbol has been used as a binder, say
  3710   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3711   as an identifier.  Fix it by inserting a space around former
  3712   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3713   existing theory and ML files.
  3714 
  3715 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3716 
  3717 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3718   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3719   a normal (but invisible) letter. For multiple letter subscripts repeat
  3720   \<^isub> like this: x\<^isub>1\<^isub>2.
  3721 
  3722 * Pure: There are now sub-/superscripts that can span more than one
  3723   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3724   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3725   superscript. The new control characters are not identifier parts.
  3726 
  3727 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3728   content of "..." to the latex file instead of \isacntrl... . The "..."
  3729   may consist of any printable characters excluding the end bracket >.
  3730 
  3731 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3732   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3733   declare constants "final", which prevents their being given a definition
  3734   later.  It is useful for constants whose behaviour is fixed axiomatically
  3735   rather than definitionally, such as the meta-logic connectives.
  3736 
  3737 * Pure: 'instance' now handles general arities with general sorts
  3738   (i.e. intersections of classes),
  3739 
  3740 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3741   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3742   It can be changed to alter the colors/layout of generated pages.
  3743 
  3744 
  3745 *** Isar ***
  3746 
  3747 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3748   cut_tac, subgoal_tac and thin_tac:
  3749   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3750     locales are no longer forced to write Isar proof scripts.
  3751     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3752     emulations.
  3753   - INCOMPATIBILITY: names of variables to be instantiated may no
  3754     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3755     This is consistent with the instantiation attribute "where".
  3756 
  3757 * Attributes "where" and "of":
  3758   - Now take type variables of instantiated theorem into account when reading
  3759     the instantiation string.  This fixes a bug that caused instantiated
  3760     theorems to have too special types in some circumstances.
  3761   - "where" permits explicit instantiations of type variables.
  3762 
  3763 * Calculation commands "moreover" and "also" no longer interfere with
  3764   current facts ("this"), admitting arbitrary combinations with "then"
  3765   and derived forms.
  3766 
  3767 * Locales:
  3768   - Goal statements involving the context element "includes" no longer
  3769     generate theorems with internal delta predicates (those ending on
  3770     "_axioms") in the premise.
  3771     Resolve particular premise with <locale>.intro to obtain old form.
  3772   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3773     specification and "includes" elements in goal statement.
  3774   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3775     [intro?] and [elim?] (respectively) by default.
  3776   - Experimental command for instantiation of locales in proof contexts:
  3777         instantiate <label>[<attrs>]: <loc>
  3778     Instantiates locale <loc> and adds all its theorems to the current context
  3779     taking into account their attributes.  Label and attrs are optional
  3780     modifiers, like in theorem declarations.  If present, names of
  3781     instantiated theorems are qualified with <label>, and the attributes
  3782     <attrs> are applied after any attributes these theorems might have already.
  3783       If the locale has assumptions, a chained fact of the form
  3784     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3785     are derived.  The command does not support old-style locales declared
  3786     with "locale (open)".
  3787       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3788 
  3789 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3790   (Isar) contexts.
  3791 
  3792 
  3793 *** HOL ***
  3794 
  3795 * Proof import: new image HOL4 contains the imported library from
  3796   the HOL4 system with about 2500 theorems. It is imported by
  3797   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3798   can be used like any other Isabelle image.  See
  3799   HOL/Import/HOL/README for more information.
  3800 
  3801 * Simplifier:
  3802   - Much improved handling of linear and partial orders.
  3803     Reasoners for linear and partial orders are set up for type classes
  3804     "linorder" and "order" respectively, and are added to the default simpset
  3805     as solvers.  This means that the simplifier can build transitivity chains
  3806     to solve goals from the assumptions.
  3807   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3808     of blast or auto after simplification become unnecessary because the goal
  3809     is solved by simplification already.
  3810 
  3811 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3812     all proved in axiomatic type classes for semirings, rings and fields.
  3813 
  3814 * Numerics:
  3815   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3816     now formalized using the Ring_and_Field theory mentioned above.
  3817   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3818     than before, because now they are set up once in a generic manner.
  3819   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3820     Look for the general versions in Ring_and_Field (and Power if they concern
  3821     exponentiation).
  3822 
  3823 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3824 
  3825 * Records:
  3826   - Record types are now by default printed with their type abbreviation
  3827     instead of the list of all field types. This can be configured via
  3828     the reference "print_record_type_abbr".
  3829   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3830     (not enabled by default).
  3831   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3832     EX x. x = sel r to True (not enabled by default).
  3833   - Tactic "record_split_simp_tac" to split and simplify records added.
  3834 
  3835 * 'specification' command added, allowing for definition by
  3836   specification.  There is also an 'ax_specification' command that
  3837   introduces the new constants axiomatically.
  3838 
  3839 * arith(_tac) is now able to generate counterexamples for reals as well.
  3840 
  3841 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3842 
  3843 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3844   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3845 
  3846 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3847   matrix theory to linear programming.
  3848 
  3849 * Unions and Intersections:
  3850   The latex output syntax of UN and INT has been changed
  3851   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3852   i.e. the index formulae has become a subscript.
  3853   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3854 
  3855 * Unions and Intersections over Intervals:
  3856   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3857   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3858   like in normal math, and corresponding versions for < and for intersection.
  3859 
  3860 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3861   lexicographic dictonary ordering has been added as "lexord".
  3862 
  3863 * ML: the legacy theory structures Int and List have been removed. They had
  3864   conflicted with ML Basis Library structures having the same names.
  3865 
  3866 * 'refute' command added to search for (finite) countermodels.  Only works
  3867   for a fragment of HOL.  The installation of an external SAT solver is
  3868   highly recommended.  See "HOL/Refute.thy" for details.
  3869 
  3870 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3871   formulae under an assignment of free variables to random values.
  3872   In contrast to 'refute', it can deal with inductive datatypes,
  3873   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3874   for examples.
  3875 
  3876 
  3877 *** HOLCF ***
  3878 
  3879 * Streams now come with concatenation and are part of the HOLCF image
  3880 
  3881 
  3882 
  3883 New in Isabelle2003 (May 2003)
  3884 ------------------------------
  3885 
  3886 *** General ***
  3887 
  3888 * Provers/simplifier:
  3889 
  3890   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3891     Assumptions are now subject to complete mutual simplification,
  3892     not just from left to right. The simplifier now preserves
  3893     the order of assumptions.
  3894 
  3895     Potential INCOMPATIBILITY:
  3896 
  3897     -- simp sometimes diverges where the old version did
  3898        not, e.g. invoking simp on the goal
  3899 
  3900         [| P (f x); y = x; f x = f y |] ==> Q
  3901 
  3902        now gives rise to the infinite reduction sequence
  3903 
  3904         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3905 
  3906        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3907        kind of problem.
  3908 
  3909     -- Tactics combining classical reasoner and simplification (such as auto)
  3910        are also affected by this change, because many of them rely on
  3911        simp. They may sometimes diverge as well or yield a different numbers
  3912        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3913        in case of problems. Sometimes subsequent calls to the classical
  3914        reasoner will fail because a preceeding call to the simplifier too
  3915        eagerly simplified the goal, e.g. deleted redundant premises.
  3916 
  3917   - The simplifier trace now shows the names of the applied rewrite rules
  3918 
  3919   - You can limit the number of recursive invocations of the simplifier
  3920     during conditional rewriting (where the simplifie tries to solve the
  3921     conditions before applying the rewrite rule):
  3922     ML "simp_depth_limit := n"
  3923     where n is an integer. Thus you can force termination where previously
  3924     the simplifier would diverge.
  3925 
  3926   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3927 
  3928   - No longer aborts on failed congruence proof.  Instead, the
  3929     congruence is ignored.
  3930 
  3931 * Pure: New generic framework for extracting programs from constructive
  3932   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3933   as HOL/Extraction for some case studies.
  3934 
  3935 * Pure: The main goal of the proof state is no longer shown by default, only
  3936 the subgoals. This behaviour is controlled by a new flag.
  3937    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3938 (ML: Proof.show_main_goal).
  3939 
  3940 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3941 rules whose conclusion matches subgoal 1:
  3942       PG menu: Isabelle/Isar -> Show me -> matching rules
  3943 The rules are ordered by how closely they match the subgoal.
  3944 In particular, rules that solve a subgoal outright are displayed first
  3945 (or rather last, the way they are printed).
  3946 (ML: ProofGeneral.print_intros())
  3947 
  3948 * Pure: New flag trace_unify_fail causes unification to print
  3949 diagnostic information (PG: in trace buffer) when it fails. This is
  3950 useful for figuring out why single step proofs like rule, erule or
  3951 assumption failed.
  3952 
  3953 * Pure: Locale specifications now produce predicate definitions
  3954 according to the body of text (covering assumptions modulo local
  3955 definitions); predicate "loc_axioms" covers newly introduced text,
  3956 while "loc" is cumulative wrt. all included locale expressions; the
  3957 latter view is presented only on export into the global theory
  3958 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3959 on the old view without predicates;
  3960 
  3961 * Pure: predefined locales "var" and "struct" are useful for sharing
  3962 parameters (as in CASL, for example); just specify something like
  3963 ``var x + var y + struct M'' as import;
  3964 
  3965 * Pure: improved thms_containing: proper indexing of facts instead of
  3966 raw theorems; check validity of results wrt. current name space;
  3967 include local facts of proof configuration (also covers active
  3968 locales), cover fixed variables in index; may use "_" in term
  3969 specification; an optional limit for the number of printed facts may
  3970 be given (the default is 40);
  3971 
  3972 * Pure: disallow duplicate fact bindings within new-style theory files
  3973 (batch-mode only);
  3974 
  3975 * Provers: improved induct method: assumptions introduced by case
  3976 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3977 the goal statement); "foo" still refers to all facts collectively;
  3978 
  3979 * Provers: the function blast.overloaded has been removed: all constants
  3980 are regarded as potentially overloaded, which improves robustness in exchange
  3981 for slight decrease in efficiency;
  3982 
  3983 * Provers/linorder: New generic prover for transitivity reasoning over
  3984 linear orders.  Note: this prover is not efficient!
  3985 
  3986 * Isar: preview of problems to finish 'show' now produce an error
  3987 rather than just a warning (in interactive mode);
  3988 
  3989 
  3990 *** HOL ***
  3991 
  3992 * arith(_tac)
  3993 
  3994  - Produces a counter example if it cannot prove a goal.
  3995    Note that the counter example may be spurious if the goal is not a formula
  3996    of quantifier-free linear arithmetic.
  3997    In ProofGeneral the counter example appears in the trace buffer.
  3998 
  3999  - Knows about div k and mod k where k is a numeral of type nat or int.
  4000 
  4001  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  4002    linear arithmetic fails. This takes account of quantifiers and divisibility.
  4003    Presburger arithmetic can also be called explicitly via presburger(_tac).
  4004 
  4005 * simp's arithmetic capabilities have been enhanced a bit: it now
  4006 takes ~= in premises into account (by performing a case split);
  4007 
  4008 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  4009 are distributed over a sum of terms;
  4010 
  4011 * New tactic "trans_tac" and method "trans" instantiate
  4012 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  4013 "<=", "<" and "=").
  4014 
  4015 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  4016 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  4017 
  4018 * 'typedef' command has new option "open" to suppress the set
  4019 definition;
  4020 
  4021 * functions Min and Max on finite sets have been introduced (theory
  4022 Finite_Set);
  4023 
  4024 * attribute [symmetric] now works for relations as well; it turns
  4025 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4026 
  4027 * induct over a !!-quantified statement (say !!x1..xn):
  4028   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4029 
  4030 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4031 %x. None. Warning: empty_def now refers to the previously hidden definition
  4032 of the empty set.
  4033 
  4034 * Algebra: formalization of classical algebra.  Intended as base for
  4035 any algebraic development in Isabelle.  Currently covers group theory
  4036 (up to Sylow's theorem) and ring theory (Universal Property of
  4037 Univariate Polynomials).  Contributions welcome;
  4038 
  4039 * GroupTheory: deleted, since its material has been moved to Algebra;
  4040 
  4041 * Complex: new directory of the complex numbers with numeric constants,
  4042 nonstandard complex numbers, and some complex analysis, standard and
  4043 nonstandard (Jacques Fleuriot);
  4044 
  4045 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4046 
  4047 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4048 Fleuriot);
  4049 
  4050 * Real/HahnBanach: updated and adapted to locales;
  4051 
  4052 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4053 Gray and Kramer);
  4054 
  4055 * UNITY: added the Meier-Sanders theory of progress sets;
  4056 
  4057 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4058 as abstract algorithms, instantiated to the JVM;
  4059 
  4060 * Bali: Java source language formalization. Type system, operational
  4061 semantics, axiomatic semantics. Supported language features:
  4062 classes, interfaces, objects,virtual methods, static methods,
  4063 static/instance fields, arrays, access modifiers, definite
  4064 assignment, exceptions.
  4065 
  4066 
  4067 *** ZF ***
  4068 
  4069 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4070 universe, etc.);
  4071 
  4072 * Main ZF: virtually all theories converted to new-style format;
  4073 
  4074 
  4075 *** ML ***
  4076 
  4077 * Pure: Tactic.prove provides sane interface for internal proofs;
  4078 omits the infamous "standard" operation, so this is more appropriate
  4079 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4080 
  4081 * Pure: improved error reporting of simprocs;
  4082 
  4083 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4084 up simprocs;
  4085 
  4086 
  4087 *** Document preparation ***
  4088 
  4089 * uses \par instead of \\ for line breaks in theory text. This may
  4090 shift some page breaks in large documents. To get the old behaviour
  4091 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4092 
  4093 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4094 other packages
  4095 
  4096 * \<euro> now needs package babel/greek instead of marvosym (which
  4097 broke \Rightarrow)
  4098 
  4099 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4100 textcomp package)
  4101 
  4102 
  4103 
  4104 New in Isabelle2002 (March 2002)
  4105 --------------------------------
  4106 
  4107 *** Document preparation ***
  4108 
  4109 * greatly simplified document preparation setup, including more
  4110 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4111 instructive isatool mkdir; users should basically be able to get
  4112 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4113 users may run a separate document processing stage manually like this:
  4114 "isatool usedir -D output HOL Test && isatool document Test/output";
  4115 
  4116 * theory dependency graph may now be incorporated into documents;
  4117 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4118 with \includegraphics of LaTeX;
  4119 
  4120 * proper spacing of consecutive markup elements, especially text
  4121 blocks after section headings;
  4122 
  4123 * support bold style (for single symbols only), input syntax is like
  4124 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4125 
  4126 * \<bullet> is now output as bold \cdot by default, which looks much
  4127 better in printed text;
  4128 
  4129 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4130 note that these symbols are currently unavailable in Proof General /
  4131 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4132 
  4133 * isatool latex no longer depends on changed TEXINPUTS, instead
  4134 isatool document copies the Isabelle style files to the target
  4135 location;
  4136 
  4137 
  4138 *** Isar ***
  4139 
  4140 * Pure/Provers: improved proof by cases and induction;
  4141   - 'case' command admits impromptu naming of parameters (such as
  4142     "case (Suc n)");
  4143   - 'induct' method divinates rule instantiation from the inductive
  4144     claim; no longer requires excessive ?P bindings for proper
  4145     instantiation of cases;
  4146   - 'induct' method properly enumerates all possibilities of set/type
  4147     rules; as a consequence facts may be also passed through *type*
  4148     rules without further ado;
  4149   - 'induct' method now derives symbolic cases from the *rulified*
  4150     rule (before it used to rulify cases stemming from the internal
  4151     atomized version); this means that the context of a non-atomic
  4152     statement becomes is included in the hypothesis, avoiding the
  4153     slightly cumbersome show "PROP ?case" form;
  4154   - 'induct' may now use elim-style induction rules without chaining
  4155     facts, using ``missing'' premises from the goal state; this allows
  4156     rules stemming from inductive sets to be applied in unstructured
  4157     scripts, while still benefitting from proper handling of non-atomic
  4158     statements; NB: major inductive premises need to be put first, all
  4159     the rest of the goal is passed through the induction;
  4160   - 'induct' proper support for mutual induction involving non-atomic
  4161     rule statements (uses the new concept of simultaneous goals, see
  4162     below);
  4163   - append all possible rule selections, but only use the first
  4164     success (no backtracking);
  4165   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4166   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4167   - added 'print_induct_rules' (covered by help item in recent Proof
  4168     General versions);
  4169   - moved induct/cases attributes to Pure, methods to Provers;
  4170   - generic method setup instantiated for FOL and HOL;
  4171 
  4172 * Pure: support multiple simultaneous goal statements, for example
  4173 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4174 meta-level mechanism, this acts as if several individual goals had
  4175 been stated separately; in particular common proof methods need to be
  4176 repeated in order to cover all claims; note that a single elimination
  4177 step is *not* sufficient to establish the two conjunctions, so this
  4178 fails:
  4179 
  4180   assume "A & B" then have A and B ..   (*".." fails*)
  4181 
  4182 better use "obtain" in situations as above; alternative refer to
  4183 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4184 
  4185 * Pure: proper integration with ``locales''; unlike the original
  4186 version by Florian Kammller, Isar locales package high-level proof
  4187 contexts rather than raw logical ones (e.g. we admit to include
  4188 attributes everywhere); operations on locales include merge and
  4189 rename; support for implicit arguments (``structures''); simultaneous
  4190 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4191 some examples;
  4192 
  4193 * Pure: the following commands have been ``localized'', supporting a
  4194 target locale specification "(in name)": 'lemma', 'theorem',
  4195 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4196 stored both within the locale and at the theory level (exported and
  4197 qualified by the locale name);
  4198 
  4199 * Pure: theory goals may now be specified in ``long'' form, with
  4200 ad-hoc contexts consisting of arbitrary locale elements. for example
  4201 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4202 definitions may be given, too); the result is a meta-level rule with
  4203 the context elements being discharged in the obvious way;
  4204 
  4205 * Pure: new proof command 'using' allows to augment currently used
  4206 facts after a goal statement ('using' is syntactically analogous to
  4207 'apply', but acts on the goal's facts only); this allows chained facts
  4208 to be separated into parts given before and after a claim, as in
  4209 ``from a and b have C using d and e <proof>'';
  4210 
  4211 * Pure: renamed "antecedent" case to "rule_context";
  4212 
  4213 * Pure: new 'judgment' command records explicit information about the
  4214 object-logic embedding (used by several tools internally); no longer
  4215 use hard-wired "Trueprop";
  4216 
  4217 * Pure: added 'corollary' command;
  4218 
  4219 * Pure: fixed 'token_translation' command;
  4220 
  4221 * Pure: removed obsolete 'exported' attribute;
  4222 
  4223 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4224 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4225 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4226 
  4227 * Pure: method 'atomize' presents local goal premises as object-level
  4228 statements (atomic meta-level propositions); setup controlled via
  4229 rewrite rules declarations of 'atomize' attribute; example
  4230 application: 'induct' method with proper rule statements in improper
  4231 proof *scripts*;
  4232 
  4233 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4234 now consider the syntactic context of assumptions, giving a better
  4235 chance to get type-inference of the arguments right (this is
  4236 especially important for locales);
  4237 
  4238 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4239 mode;
  4240 
  4241 * Pure/obtain: the formal conclusion "thesis", being marked as
  4242 ``internal'', may no longer be reference directly in the text;
  4243 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4244 situations;
  4245 
  4246 * Pure: generic 'sym' attribute which declares a rule both as pure
  4247 'elim?' and for the 'symmetric' operation;
  4248 
  4249 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4250 text; the fixed correlation with particular command syntax has been
  4251 discontinued;
  4252 
  4253 * Pure: new method 'rules' is particularly well-suited for proof
  4254 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4255 but often produces more compact proof terms with less detours;
  4256 
  4257 * Pure/Provers/classical: simplified integration with pure rule
  4258 attributes and methods; the classical "intro?/elim?/dest?"
  4259 declarations coincide with the pure ones; the "rule" method no longer
  4260 includes classically swapped intros; "intro" and "elim" methods no
  4261 longer pick rules from the context; also got rid of ML declarations
  4262 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4263 INCOMPATIBILITY;
  4264 
  4265 * Provers/classical: attribute 'swapped' produces classical inversions
  4266 of introduction rules;
  4267 
  4268 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4269 rules instead of full simplifier context; 'iff' attribute handles
  4270 conditional rules;
  4271 
  4272 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4273 
  4274 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4275 "(permissive)" option to recover old behavior;
  4276 
  4277 * HOL: 'inductive' no longer features separate (collective) attributes
  4278 for 'intros' (was found too confusing);
  4279 
  4280 * HOL: properly declared induction rules less_induct and
  4281 wf_induct_rule;
  4282 
  4283 
  4284 *** HOL ***
  4285 
  4286 * HOL: moved over to sane numeral syntax; the new policy is as
  4287 follows:
  4288 
  4289   - 0 and 1 are polymorphic constants, which are defined on any
  4290   numeric type (nat, int, real etc.);
  4291 
  4292   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4293   binary representation internally;
  4294 
  4295   - type nat has special constructor Suc, and generally prefers Suc 0
  4296   over 1::nat and Suc (Suc 0) over 2::nat;
  4297 
  4298 This change may cause significant problems of INCOMPATIBILITY; here
  4299 are some hints on converting existing sources:
  4300 
  4301   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4302   entities, so expressions involving "-" (unary or binary minus) need
  4303   to be spaced properly;
  4304 
  4305   - existing occurrences of "1" may need to be constraint "1::nat" or
  4306   even replaced by Suc 0; similar for old "2";
  4307 
  4308   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4309 
  4310   - remove all special provisions on numerals in proofs;
  4311 
  4312 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4313 representation (depends on bin_arith_simps in the default context);
  4314 
  4315 * HOL: symbolic syntax for x^2 (numeral 2);
  4316 
  4317 * HOL: the class of all HOL types is now called "type" rather than
  4318 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4319 in axclass/classes, instance/arities, and (usually rare) occurrences
  4320 in typings (of consts etc.); internally the class is called
  4321 "HOL.type", ML programs should refer to HOLogic.typeS;
  4322 
  4323 * HOL/record package improvements:
  4324   - new derived operations "fields" to build a partial record section,
  4325     "extend" to promote a fixed record to a record scheme, and
  4326     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4327     declared as simp by default;
  4328   - shared operations ("more", "fields", etc.) now need to be always
  4329     qualified) --- potential INCOMPATIBILITY;
  4330   - removed "make_scheme" operations (use "make" with "extend") --
  4331     INCOMPATIBILITY;
  4332   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4333   - provides cases/induct rules for use with corresponding Isar
  4334     methods (for concrete records, record schemes, concrete more
  4335     parts, and schematic more parts -- in that order);
  4336   - internal definitions directly based on a light-weight abstract
  4337     theory of product types over typedef rather than datatype;
  4338 
  4339 * HOL: generic code generator for generating executable ML code from
  4340 specifications; specific support for HOL constructs such as inductive
  4341 datatypes and sets, as well as recursive functions; can be invoked
  4342 via 'generate_code' theory section;
  4343 
  4344 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4345 
  4346 * HOL: consolidated and renamed several theories.  In particular:
  4347         Ord.thy has been absorbed into HOL.thy
  4348         String.thy has been absorbed into List.thy
  4349 
  4350 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4351 (beware of argument permutation!);
  4352 
  4353 * HOL: linorder_less_split superseded by linorder_cases;
  4354 
  4355 * HOL/List: "nodups" renamed to "distinct";
  4356 
  4357 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4358 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4359   - Ex_def has changed, now need to use some_eq_ex
  4360 
  4361 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4362 in this (rare) case use:
  4363 
  4364   delSWrapper "split_all_tac"
  4365   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4366 
  4367 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4368 MAY FAIL;
  4369 
  4370 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4371 Isabelle's type classes, ^ on functions and relations has too general
  4372 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4373 necessary to attach explicit type constraints;
  4374 
  4375 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4376 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4377 renamed accordingly (eg "compI" -> "rel_compI").
  4378 
  4379 * HOL: syntax translations now work properly with numerals and records
  4380 expressions;
  4381 
  4382 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4383 of "lam" -- INCOMPATIBILITY;
  4384 
  4385 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4386 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4387 renamed "Product_Type.unit";
  4388 
  4389 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4390 
  4391 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4392 the "cases" method);
  4393 
  4394 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4395 Florian Kammller);
  4396 
  4397 * HOL/IMP: updated and converted to new-style theory format; several
  4398 parts turned into readable document, with proper Isar proof texts and
  4399 some explanations (by Gerwin Klein);
  4400 
  4401 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4402 
  4403 * HOL-Hyperreal is now a logic image;
  4404 
  4405 
  4406 *** HOLCF ***
  4407 
  4408 * Isar: consts/constdefs supports mixfix syntax for continuous
  4409 operations;
  4410 
  4411 * Isar: domain package adapted to new-style theory format, e.g. see
  4412 HOLCF/ex/Dnat.thy;
  4413 
  4414 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4415 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4416 lift.induct_tac, always use UU instead of Undef;
  4417 
  4418 * HOLCF/IMP: updated and converted to new-style theory;
  4419 
  4420 
  4421 *** ZF ***
  4422 
  4423 * Isar: proper integration of logic-specific tools and packages,
  4424 including theory commands '(co)inductive', '(co)datatype',
  4425 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4426 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4427 
  4428 * theory Main no longer includes AC; for the Axiom of Choice, base
  4429 your theory on Main_ZFC;
  4430 
  4431 * the integer library now covers quotients and remainders, with many
  4432 laws relating division to addition, multiplication, etc.;
  4433 
  4434 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4435 typeless version of the formalism;
  4436 
  4437 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4438 format;
  4439 
  4440 * ZF/Induct: new directory for examples of inductive definitions,
  4441 including theory Multiset for multiset orderings; converted to
  4442 new-style theory format;
  4443 
  4444 * ZF: many new theorems about lists, ordinals, etc.;
  4445 
  4446 
  4447 *** General ***
  4448 
  4449 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4450 variable proof controls level of detail: 0 = no proofs (only oracle
  4451 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4452 also ref manual for further ML interfaces;
  4453 
  4454 * Pure/axclass: removed obsolete ML interface
  4455 goal_subclass/goal_arity;
  4456 
  4457 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4458 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4459 separate tokens, so expressions involving minus need to be spaced
  4460 properly;
  4461 
  4462 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4463 rather than "infixl" or "infixr";
  4464 
  4465 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4466 sort constraint specifications in type inference; e.g. "x::_::foo"
  4467 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4468 type variable);
  4469 
  4470 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4471 control output of nested => (types); the default behavior is
  4472 "type_brackets";
  4473 
  4474 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4475 tokens into AST constants;
  4476 
  4477 * Pure/syntax: prefer later declarations of translations and print
  4478 translation functions; potential INCOMPATIBILITY: need to reverse
  4479 multiple declarations for same syntax element constant;
  4480 
  4481 * Pure/show_hyps reset by default (in accordance to existing Isar
  4482 practice);
  4483 
  4484 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4485 addSafter;
  4486 
  4487 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4488 as well;
  4489 
  4490 * system: tested support for MacOS X; should be able to get Isabelle +
  4491 Proof General to work in a plain Terminal after installing Poly/ML
  4492 (e.g. from the Isabelle distribution area) and GNU bash alone
  4493 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4494 support requires further installations, e.g. from
  4495 http://fink.sourceforge.net/);
  4496 
  4497 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4498 
  4499 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4500 of 40 MB), cf. ML_OPTIONS;
  4501 
  4502 * system: Proof General keywords specification is now part of the
  4503 Isabelle distribution (see etc/isar-keywords.el);
  4504 
  4505 * system: support for persistent Proof General sessions (refrain from
  4506 outdating all loaded theories on startup); user may create writable
  4507 logic images like this: ``isabelle -q HOL Test'';
  4508 
  4509 * system: smart selection of Isabelle process versus Isabelle
  4510 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4511 run both "isabelle" and "Isabelle" even if file names are badly
  4512 damaged (executable inspects the case of the first letter of its own
  4513 name); added separate "isabelle-process" and "isabelle-interface";
  4514 
  4515 * system: refrain from any attempt at filtering input streams; no
  4516 longer support ``8bit'' encoding of old isabelle font, instead proper
  4517 iso-latin characters may now be used; the related isatools
  4518 "symbolinput" and "nonascii" have disappeared as well;
  4519 
  4520 * system: removed old "xterm" interface (the print modes "xterm" and
  4521 "xterm_color" are still available for direct use in a suitable
  4522 terminal);
  4523 
  4524 
  4525 
  4526 New in Isabelle99-2 (February 2001)
  4527 -----------------------------------
  4528 
  4529 *** Overview of INCOMPATIBILITIES ***
  4530 
  4531 * HOL: please note that theories in the Library and elsewhere often use the
  4532 new-style (Isar) format; to refer to their theorems in an ML script you must
  4533 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4534 
  4535 * HOL: inductive package no longer splits induction rule aggressively,
  4536 but only as far as specified by the introductions given; the old
  4537 format may be recovered via ML function complete_split_rule or attribute
  4538 'split_rule (complete)';
  4539 
  4540 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4541 gfp_Tarski to gfp_unfold;
  4542 
  4543 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4544 
  4545 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4546 relation); infix "^^" has been renamed "``"; infix "``" has been
  4547 renamed "`"; "univalent" has been renamed "single_valued";
  4548 
  4549 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4550 operation;
  4551 
  4552 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4553 
  4554 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4555 
  4556 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4557 consequence, it is no longer monotonic wrt. the local goal context
  4558 (which is now passed through the inductive cases);
  4559 
  4560 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4561 \<gg> to \<ggreater>;
  4562 
  4563 
  4564 *** Document preparation ***
  4565 
  4566 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4567 available: are "it" for near math-mode best-style output, "sl" for
  4568 slanted text style, and "tt" for plain type-writer; if no
  4569 \isabellestyle command is given, output is according to slanted
  4570 type-writer);
  4571 
  4572 * support sub/super scripts (for single symbols only), input syntax is
  4573 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4574 
  4575 * some more standard symbols; see Appendix A of the system manual for
  4576 the complete list of symbols defined in isabellesym.sty;
  4577 
  4578 * improved isabelle style files; more abstract symbol implementation
  4579 (should now use \isamath{...} and \isatext{...} in custom symbol
  4580 definitions);
  4581 
  4582 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4583 state; Note that presentation of goal states does not conform to
  4584 actual human-readable proof documents.  Please do not include goal
  4585 states into document output unless you really know what you are doing!
  4586 
  4587 * proper indentation of antiquoted output with proportional LaTeX
  4588 fonts;
  4589 
  4590 * no_document ML operator temporarily disables LaTeX document
  4591 generation;
  4592 
  4593 * isatool unsymbolize tunes sources for plain ASCII communication;
  4594 
  4595 
  4596 *** Isar ***
  4597 
  4598 * Pure: Isar now suffers initial goal statements to contain unbound
  4599 schematic variables (this does not conform to actual readable proof
  4600 documents, due to unpredictable outcome and non-compositional proof
  4601 checking); users who know what they are doing may use schematic goals
  4602 for Prolog-style synthesis of proven results;
  4603 
  4604 * Pure: assumption method (an implicit finishing) now handles actual
  4605 rules as well;
  4606 
  4607 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4608 initial goal, declare "that" only as Pure intro (only for single
  4609 steps); the "that" rule assumption may now be involved in implicit
  4610 finishing, thus ".." becomes a feasible for trivial obtains;
  4611 
  4612 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4613 instance proofs may be performed by "..";
  4614 
  4615 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4616 statements as well;
  4617 
  4618 * Pure: more robust selection of calculational rules;
  4619 
  4620 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4621 rule (as well as the assumption rule);
  4622 
  4623 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4624 lemmas, using the graph browser tool;
  4625 
  4626 * Pure: predict failure of "show" in interactive mode;
  4627 
  4628 * Pure: 'thms_containing' now takes actual terms as arguments;
  4629 
  4630 * HOL: improved method 'induct' --- now handles non-atomic goals
  4631 (potential INCOMPATIBILITY); tuned error handling;
  4632 
  4633 * HOL: cases and induct rules now provide explicit hints about the
  4634 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4635 any remaining facts are inserted into the goal verbatim;
  4636 
  4637 * HOL: local contexts (aka cases) may now contain term bindings as
  4638 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4639 the result to be shown in each case;
  4640 
  4641 * HOL: added 'recdef_tc' command;
  4642 
  4643 * isatool convert assists in eliminating legacy ML scripts;
  4644 
  4645 
  4646 *** HOL ***
  4647 
  4648 * HOL/Library: a collection of generic theories to be used together
  4649 with main HOL; the theory loader path already includes this directory
  4650 by default; the following existing theories have been moved here:
  4651 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4652 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4653 
  4654 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4655 modelling and verification task performed in Isabelle/HOL +
  4656 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4657 
  4658 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4659 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4660 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4661 'domain', this makes the theory consistent with mathematical
  4662 literature;
  4663 
  4664 * HOL basics: added overloaded operations "inverse" and "divide"
  4665 (infix "/"), syntax for generic "abs" operation, generic summation
  4666 operator \<Sum>;
  4667 
  4668 * HOL/typedef: simplified package, provide more useful rules (see also
  4669 HOL/subset.thy);
  4670 
  4671 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4672 now expressed as a proper nested rule (old-style tactic scripts may
  4673 require atomize_strip_tac to cope with non-atomic premises);
  4674 
  4675 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4676 to "split_conv" (old name still available for compatibility);
  4677 
  4678 * HOL: improved concrete syntax for strings (e.g. allows translation
  4679 rules with string literals);
  4680 
  4681 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4682  and Fleuriot's mechanization of analysis, including the transcendental
  4683  functions for the reals;
  4684 
  4685 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4686 
  4687 
  4688 *** CTT ***
  4689 
  4690 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4691 "lam" is displayed as TWO lambda-symbols
  4692 
  4693 * CTT: theory Main now available, containing everything (that is, Bool
  4694 and Arith);
  4695 
  4696 
  4697 *** General ***
  4698 
  4699 * Pure: the Simplifier has been implemented properly as a derived rule
  4700 outside of the actual kernel (at last!); the overall performance
  4701 penalty in practical applications is about 50%, while reliability of
  4702 the Isabelle inference kernel has been greatly improved;
  4703 
  4704 * print modes "brackets" and "no_brackets" control output of nested =>
  4705 (types) and ==> (props); the default behaviour is "brackets";
  4706 
  4707 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4708 as assumptions as well;
  4709 
  4710 * system: support Poly/ML 4.0;
  4711 
  4712 * system: isatool install handles KDE version 1 or 2;
  4713 
  4714 
  4715 
  4716 New in Isabelle99-1 (October 2000)
  4717 ----------------------------------
  4718 
  4719 *** Overview of INCOMPATIBILITIES ***
  4720 
  4721 * HOL: simplification of natural numbers is much changed; to partly
  4722 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4723 issue the following ML commands:
  4724 
  4725   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4726   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4727 
  4728 * HOL: simplification no longer dives into case-expressions; this is
  4729 controlled by "t.weak_case_cong" for each datatype t;
  4730 
  4731 * HOL: nat_less_induct renamed to less_induct;
  4732 
  4733 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4734 fixsome to patch .thy and .ML sources automatically;
  4735 
  4736   select_equality  -> some_equality
  4737   select_eq_Ex     -> some_eq_ex
  4738   selectI2EX       -> someI2_ex
  4739   selectI2         -> someI2
  4740   selectI          -> someI
  4741   select1_equality -> some1_equality
  4742   Eps_sym_eq       -> some_sym_eq_trivial
  4743   Eps_eq           -> some_eq_trivial
  4744 
  4745 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4746 
  4747 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4748 instead);
  4749 
  4750 * HOL: the recursion equations generated by 'recdef' are now called
  4751 f.simps instead of f.rules;
  4752 
  4753 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4754 
  4755 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4756 sometimes be needed;
  4757 
  4758 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4759 
  4760 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4761 
  4762 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4763 product is now "<*>" instead of "Times"; the lexicographic product is
  4764 now "<*lex*>" instead of "**";
  4765 
  4766 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4767 of main HOL, but was unused); better use HOL's datatype package;
  4768 
  4769 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4770 the old syntax may be recovered as follows:
  4771 
  4772   syntax (symbols)
  4773     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4774       (infixl "\\<oplus>" 100)
  4775 
  4776 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4777 
  4778 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4779 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4780 internally;
  4781 
  4782 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4783 changed from A/r to A//r;
  4784 
  4785 * ZF: new treatment of arithmetic (nat & int) may break some old
  4786 proofs;
  4787 
  4788 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4789 rulify -> rule_format, elimify -> elim_format, ...);
  4790 
  4791 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4792 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4793 should have to change intro!! to intro? only); replaced "delrule" by
  4794 "rule del";
  4795 
  4796 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4797 
  4798 * Provers: strengthened force_tac by using new first_best_tac;
  4799 
  4800 * LaTeX document preparation: several changes of isabelle.sty (see
  4801 lib/texinputs);
  4802 
  4803 
  4804 *** Document preparation ***
  4805 
  4806 * formal comments (text blocks etc.) in new-style theories may now
  4807 contain antiquotations of thm/prop/term/typ/text to be presented
  4808 according to latex print mode; concrete syntax is like this:
  4809 @{term[show_types] "f(x) = a + x"};
  4810 
  4811 * isatool mkdir provides easy setup of Isabelle session directories,
  4812 including proper document sources;
  4813 
  4814 * generated LaTeX sources are now deleted after successful run
  4815 (isatool document -c); may retain a copy somewhere else via -D option
  4816 of isatool usedir;
  4817 
  4818 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4819 style files, achieving self-contained LaTeX sources and simplifying
  4820 LaTeX debugging;
  4821 
  4822 * old-style theories now produce (crude) LaTeX output as well;
  4823 
  4824 * browser info session directories are now self-contained (may be put
  4825 on WWW server seperately); improved graphs of nested sessions; removed
  4826 graph for 'all sessions';
  4827 
  4828 * several improvements in isabelle style files; \isabellestyle{it}
  4829 produces fake math mode output; \isamarkupheader is now \section by
  4830 default; see lib/texinputs/isabelle.sty etc.;
  4831 
  4832 
  4833 *** Isar ***
  4834 
  4835 * Isar/Pure: local results and corresponding term bindings are now
  4836 subject to Hindley-Milner polymorphism (similar to ML); this
  4837 accommodates incremental type-inference very nicely;
  4838 
  4839 * Isar/Pure: new derived language element 'obtain' supports
  4840 generalized existence reasoning;
  4841 
  4842 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4843 support accumulation of results, without applying any rules yet;
  4844 useful to collect intermediate results without explicit name
  4845 references, and for use with transitivity rules with more than 2
  4846 premises;
  4847 
  4848 * Isar/Pure: scalable support for case-analysis type proofs: new
  4849 'case' language element refers to local contexts symbolically, as
  4850 produced by certain proof methods; internally, case names are attached
  4851 to theorems as "tags";
  4852 
  4853 * Isar/Pure: theory command 'hide' removes declarations from
  4854 class/type/const name spaces;
  4855 
  4856 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4857 indicate potential overloading;
  4858 
  4859 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4860 
  4861 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4862 "{a,b,c}" instead of {a,b,c};
  4863 
  4864 * Isar/Pure now provides its own version of intro/elim/dest
  4865 attributes; useful for building new logics, but beware of confusion
  4866 with the version in Provers/classical;
  4867 
  4868 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4869 case name 'antecedent';
  4870 
  4871 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4872 to the current context is now done automatically);
  4873 
  4874 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4875 for definining proof methods in ML;
  4876 
  4877 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4878 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4879 most cases, one should have to change intro!! to intro? only);
  4880 replaced "delrule" by "rule del";
  4881 
  4882 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4883 'symmetric' attribute (the latter supercedes [RS sym]);
  4884 
  4885 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4886 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4887 well (including splits);
  4888 
  4889 * Isar/Provers: Simplifier and Classical methods now support all kind
  4890 of modifiers used in the past, including 'cong', 'iff', etc.
  4891 
  4892 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4893 of Simplifier and Classical reasoner);
  4894 
  4895 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4896 now support named cases; major packages (inductive, datatype, primrec,
  4897 recdef) support case names and properly name parameters;
  4898 
  4899 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4900 monotonicity conditions are extracted to be proven at end of
  4901 calculations;
  4902 
  4903 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4904 method anyway;
  4905 
  4906 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4907 split_if split_if_asm; datatype package provides theorems foo.splits =
  4908 foo.split foo.split_asm for each datatype;
  4909 
  4910 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4911 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4912 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4913 use "(cases (simplified))" method in proper proof texts);
  4914 
  4915 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4916 
  4917 * Isar: names of theorems etc. may be natural numbers as well;
  4918 
  4919 * Isar: 'pr' command: optional arguments for goals_limit and
  4920 ProofContext.prems_limit; no longer prints theory contexts, but only
  4921 proof states;
  4922 
  4923 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4924 additional print modes to be specified; e.g. "pr(latex)" will print
  4925 proof state according to the Isabelle LaTeX style;
  4926 
  4927 * Isar: improved support for emulating tactic scripts, including proof
  4928 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4929 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4930 (for HOL datatypes);
  4931 
  4932 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4933 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4934 'proof method scripts' have to be in depth-first order;
  4935 
  4936 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4937 
  4938 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4939 should instead use individual commands for printing items
  4940 (print_commands, print_methods etc.);
  4941 
  4942 * Isar: added 'nothing' --- the empty list of theorems;
  4943 
  4944 
  4945 *** HOL ***
  4946 
  4947 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4948 corresponding virtual machine and a specification of its bytecode
  4949 verifier and a lightweight bytecode verifier, including proofs of
  4950 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4951 Cornelia Pusch (see also the homepage of project Bali at
  4952 http://isabelle.in.tum.de/Bali/);
  4953 
  4954 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4955 Clemens Ballarin;
  4956 
  4957 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4958 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4959 Rasmussen;
  4960 
  4961 * HOL/Lattice: fundamental concepts of lattice theory and order
  4962 structures, including duals, properties of bounds versus algebraic
  4963 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4964 Theorem for complete lattices etc.; may also serve as a demonstration
  4965 for abstract algebraic reasoning using axiomatic type classes, and
  4966 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4967 
  4968 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4969 von Oheimb;
  4970 
  4971 * HOL/IMPP: extension of IMP with local variables and mutually
  4972 recursive procedures, by David von Oheimb;
  4973 
  4974 * HOL/Lambda: converted into new-style theory and document;
  4975 
  4976 * HOL/ex/Multiquote: example of multiple nested quotations and
  4977 anti-quotations -- basically a generalized version of de-Bruijn
  4978 representation; very useful in avoiding lifting of operations;
  4979 
  4980 * HOL/record: added general record equality rule to simpset; fixed
  4981 select-update simplification procedure to handle extended records as
  4982 well; admit "r" as field name;
  4983 
  4984 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4985 other numeric types and also as the identity of groups, rings, etc.;
  4986 
  4987 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4988 Types nat and int belong to this axclass;
  4989 
  4990 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4991    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4992    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4993   two terms #m*u and #n*u are replaced by #(m+n)*u
  4994     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4995   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4996     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4997 
  4998 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4999 powerful prover for predicate logic but knows nothing of clasets; see
  5000 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  5001 
  5002 * HOL: new version of "case_tac" subsumes both boolean case split and
  5003 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  5004 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  5005 
  5006 * HOL: simplification no longer dives into case-expressions: only the
  5007 selector expression is simplified, but not the remaining arms; to
  5008 enable full simplification of case-expressions for datatype t, you may
  5009 remove t.weak_case_cong from the simpset, either globally (Delcongs
  5010 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  5011 
  5012 * HOL/recdef: the recursion equations generated by 'recdef' for
  5013 function 'f' are now called f.simps instead of f.rules; if all
  5014 termination conditions are proved automatically, these simplification
  5015 rules are added to the simpset, as in primrec; rules may be named
  5016 individually as well, resulting in a separate list of theorems for
  5017 each equation;
  5018 
  5019 * HOL/While is a new theory that provides a while-combinator. It
  5020 permits the definition of tail-recursive functions without the
  5021 provision of a termination measure. The latter is necessary once the
  5022 invariant proof rule for while is applied.
  5023 
  5024 * HOL: new (overloaded) notation for the set of elements below/above
  5025 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5026 
  5027 * HOL: theorems impI, allI, ballI bound as "strip";
  5028 
  5029 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5030 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5031 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5032 
  5033 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5034 
  5035 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5036 main HOL, but was unused);
  5037 
  5038 * HOL: fewer consts declared as global (e.g. have to refer to
  5039 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5040 
  5041 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5042 in case of overlap with user translations (e.g. judgements over
  5043 tuples); (note that the underlying logical represenation is still
  5044 bogus);
  5045 
  5046 
  5047 *** ZF ***
  5048 
  5049 * ZF: simplification automatically cancels common terms in arithmetic
  5050 expressions over nat and int;
  5051 
  5052 * ZF: new treatment of nat to minimize type-checking: all operators
  5053 coerce their operands to a natural number using the function natify,
  5054 making the algebraic laws unconditional;
  5055 
  5056 * ZF: as above, for int: operators coerce their operands to an integer
  5057 using the function intify;
  5058 
  5059 * ZF: the integer library now contains many of the usual laws for the
  5060 orderings, including $<=, and monotonicity laws for $+ and $*;
  5061 
  5062 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5063 simplification;
  5064 
  5065 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5066 to the simplifier and classical reasoner simultaneously;
  5067 
  5068 
  5069 *** General ***
  5070 
  5071 * Provers: blast_tac now handles actual object-logic rules as
  5072 assumptions; note that auto_tac uses blast_tac internally as well;
  5073 
  5074 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5075 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5076 
  5077 * Provers: delrules now handles destruct rules as well (no longer need
  5078 explicit make_elim);
  5079 
  5080 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5081   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5082 use instead the strong form,
  5083   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5084 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5085 from destruct-rules;
  5086 
  5087 * Provers: Simplifier.easy_setup provides a fast path to basic
  5088 Simplifier setup for new object-logics;
  5089 
  5090 * Pure: AST translation rules no longer require constant head on LHS;
  5091 
  5092 * Pure: improved name spaces: ambiguous output is qualified; support
  5093 for hiding of names;
  5094 
  5095 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5096 XSYMBOL_HOME; no longer need to do manual configuration in most
  5097 situations;
  5098 
  5099 * system: compression of ML heaps images may now be controlled via -c
  5100 option of isabelle and isatool usedir (currently only observed by
  5101 Poly/ML);
  5102 
  5103 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5104 useful for remote X11);
  5105 
  5106 * system: provide TAGS file for Isabelle sources;
  5107 
  5108 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5109 order;
  5110 
  5111 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5112 timing flag supersedes proof_timing and Toplevel.trace;
  5113 
  5114 * ML: new combinators |>> and |>>> for incremental transformations
  5115 with secondary results (e.g. certain theory extensions):
  5116 
  5117 * ML: PureThy.add_defs gets additional argument to indicate potential
  5118 overloading (usually false);
  5119 
  5120 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5121 results;
  5122 
  5123 
  5124 
  5125 New in Isabelle99 (October 1999)
  5126 --------------------------------
  5127 
  5128 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5129 
  5130 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5131 are no longer simplified.  (This allows the simplifier to unfold recursive
  5132 functional programs.)  To restore the old behaviour, declare
  5133 
  5134     Delcongs [if_weak_cong];
  5135 
  5136 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5137 complement;
  5138 
  5139 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5140 
  5141 * HOL/datatype: mutual_induct_tac no longer exists --
  5142   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5143 
  5144 * HOL/typedef: fixed type inference for representing set; type
  5145 arguments now have to occur explicitly on the rhs as type constraints;
  5146 
  5147 * ZF: The con_defs part of an inductive definition may no longer refer
  5148 to constants declared in the same theory;
  5149 
  5150 * HOL, ZF: the function mk_cases, generated by the inductive
  5151 definition package, has lost an argument.  To simplify its result, it
  5152 uses the default simpset instead of a supplied list of theorems.
  5153 
  5154 * HOL/List: the constructors of type list are now Nil and Cons;
  5155 
  5156 * Simplifier: the type of the infix ML functions
  5157         setSSolver addSSolver setSolver addSolver
  5158 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5159 for packaging solvers. A solver is created via
  5160         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5161 where the string argument is only a comment.
  5162 
  5163 
  5164 *** Proof tools ***
  5165 
  5166 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5167 decision procedure for linear arithmetic. Currently it is used for
  5168 types `nat', `int', and `real' in HOL (see below); it can, should and
  5169 will be instantiated for other types and logics as well.
  5170 
  5171 * The simplifier now accepts rewrite rules with flexible heads, eg
  5172      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5173   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5174   matching.
  5175 
  5176 
  5177 *** General ***
  5178 
  5179 * New Isabelle/Isar subsystem provides an alternative to traditional
  5180 tactical theorem proving; together with the ProofGeneral/isar user
  5181 interface it offers an interactive environment for developing human
  5182 readable proof documents (Isar == Intelligible semi-automated
  5183 reasoning); for further information see isatool doc isar-ref,
  5184 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5185 
  5186 * improved and simplified presentation of theories: better HTML markup
  5187 (including colors), graph views in several sizes; isatool usedir now
  5188 provides a proper interface for user theories (via -P option); actual
  5189 document preparation based on (PDF)LaTeX is available as well (for
  5190 new-style theories only); see isatool doc system for more information;
  5191 
  5192 * native support for Proof General, both for classic Isabelle and
  5193 Isabelle/Isar;
  5194 
  5195 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5196 using the graph browser tool;
  5197 
  5198 * Isabelle manuals now also available as PDF;
  5199 
  5200 * theory loader rewritten from scratch (may not be fully
  5201 bug-compatible); old loadpath variable has been replaced by show_path,
  5202 add_path, del_path, reset_path functions; new operations such as
  5203 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5204 isatool doc ref);
  5205 
  5206 * improved isatool install: option -k creates KDE application icon,
  5207 option -p DIR installs standalone binaries;
  5208 
  5209 * added ML_PLATFORM setting (useful for cross-platform installations);
  5210 more robust handling of platform specific ML images for SML/NJ;
  5211 
  5212 * the settings environment is now statically scoped, i.e. it is never
  5213 created again in sub-processes invoked from isabelle, isatool, or
  5214 Isabelle;
  5215 
  5216 * path element specification '~~' refers to '$ISABELLE_HOME';
  5217 
  5218 * in locales, the "assumes" and "defines" parts may be omitted if
  5219 empty;
  5220 
  5221 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5222 long arrows);
  5223 
  5224 * new print_mode "HTML";
  5225 
  5226 * new flag show_tags controls display of tags of theorems (which are
  5227 basically just comments that may be attached by some tools);
  5228 
  5229 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5230 mode and goal output format:
  5231 
  5232 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5233 244c244
  5234 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5235 ---
  5236 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5237 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5238 181c181
  5239 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5240 ---
  5241 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5242 
  5243 * function bind_thms stores lists of theorems (cf. bind_thm);
  5244 
  5245 * new shorthand tactics ftac, eatac, datac, fatac;
  5246 
  5247 * qed (and friends) now accept "" as result name; in that case the
  5248 theorem is not stored, but proper checks and presentation of the
  5249 result still apply;
  5250 
  5251 * theorem database now also indexes constants "Trueprop", "all",
  5252 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5253 
  5254 
  5255 *** HOL ***
  5256 
  5257 ** HOL arithmetic **
  5258 
  5259 * There are now decision procedures for linear arithmetic over nat and
  5260 int:
  5261 
  5262 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5263 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5264 are treated as atomic; subformulae not involving type `nat' or `int'
  5265 are ignored; quantified subformulae are ignored unless they are
  5266 positive universal or negative existential. The tactic has to be
  5267 invoked by hand and can be a little bit slow. In particular, the
  5268 running time is exponential in the number of occurrences of `min' and
  5269 `max', and `-' on `nat'.
  5270 
  5271 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5272 (negated) (in)equalities among the premises and the conclusion into
  5273 account (i.e. no compound formulae) and does not know about `min' and
  5274 `max', and `-' on `nat'. It is fast and is used automatically by the
  5275 simplifier.
  5276 
  5277 NB: At the moment, these decision procedures do not cope with mixed
  5278 nat/int formulae where the two parts interact, such as `m < n ==>
  5279 int(m) < int(n)'.
  5280 
  5281 * HOL/Numeral provides a generic theory of numerals (encoded
  5282 efficiently as bit strings); setup for types nat/int/real is in place;
  5283 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5284 int, existing theories and proof scripts may require a few additional
  5285 type constraints;
  5286 
  5287 * integer division and remainder can now be performed on constant
  5288 arguments;
  5289 
  5290 * many properties of integer multiplication, division and remainder
  5291 are now available;
  5292 
  5293 * An interface to the Stanford Validity Checker (SVC) is available through the
  5294 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5295 are proved automatically.  SVC must be installed separately, and its results
  5296 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5297 invocation of the underlying oracle).  For SVC see
  5298   http://verify.stanford.edu/SVC
  5299 
  5300 * IsaMakefile: the HOL-Real target now builds an actual image;
  5301 
  5302 
  5303 ** HOL misc **
  5304 
  5305 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5306 (in Isabelle/Isar) -- by Gertrud Bauer;
  5307 
  5308 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5309 analysis for assembly languages with subtypes;
  5310 
  5311 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5312 -- avoids syntactic ambiguities and treats state, transition, and
  5313 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5314 changed syntax and (many) tactics;
  5315 
  5316 * HOL/inductive: Now also handles more general introduction rules such
  5317   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5318   theorems are now maintained within the theory (maintained via the
  5319   "mono" attribute);
  5320 
  5321 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5322   (using function types) such as
  5323 
  5324   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5325 
  5326 * HOL/record: record_simproc (part of the default simpset) takes care
  5327 of selectors applied to updated records; record_split_tac is no longer
  5328 part of the default claset; update_defs may now be removed from the
  5329 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5330 
  5331   claset_ref () := claset() addSWrapper record_split_wrapper;
  5332   Delsimprocs [record_simproc]
  5333 
  5334 * HOL/typedef: fixed type inference for representing set; type
  5335 arguments now have to occur explicitly on the rhs as type constraints;
  5336 
  5337 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5338 names rather than an ML expression;
  5339 
  5340 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5341 supplied later.  Program schemes can be defined, such as
  5342     "While B C s = (if B s then While B C (C s) else s)"
  5343 where the well-founded relation can be chosen after B and C have been given.
  5344 
  5345 * HOL/List: the constructors of type list are now Nil and Cons;
  5346 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5347 course, ML tools referring to List.list.op # etc. have to be adapted;
  5348 
  5349 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5350 disabled by default; run isabelle with option -m HOL to get back to
  5351 the original Gordon/HOL-style output;
  5352 
  5353 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5354 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5355 
  5356 * HOL basic syntax simplified (more orthogonal): all variants of
  5357 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5358 Eps operator is provided as well: "SOME x. P[x]";
  5359 
  5360 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5361 
  5362 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5363 thus available for user theories;
  5364 
  5365 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5366 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5367 time;
  5368 
  5369 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5370 several times and then mp;
  5371 
  5372 
  5373 *** LK ***
  5374 
  5375 * the notation <<...>> is now available as a notation for sequences of
  5376 formulas;
  5377 
  5378 * the simplifier is now installed
  5379 
  5380 * the axiom system has been generalized (thanks to Soren Heilmann)
  5381 
  5382 * the classical reasoner now has a default rule database
  5383 
  5384 
  5385 *** ZF ***
  5386 
  5387 * new primrec section allows primitive recursive functions to be given
  5388 directly (as in HOL) over datatypes and the natural numbers;
  5389 
  5390 * new tactics induct_tac and exhaust_tac for induction (or case
  5391 analysis) over datatypes and the natural numbers;
  5392 
  5393 * the datatype declaration of type T now defines the recursor T_rec;
  5394 
  5395 * simplification automatically does freeness reasoning for datatype
  5396 constructors;
  5397 
  5398 * automatic type-inference, with AddTCs command to insert new
  5399 type-checking rules;
  5400 
  5401 * datatype introduction rules are now added as Safe Introduction rules
  5402 to the claset;
  5403 
  5404 * the syntax "if P then x else y" is now available in addition to
  5405 if(P,x,y);
  5406 
  5407 
  5408 *** Internal programming interfaces ***
  5409 
  5410 * tuned simplifier trace output; new flag debug_simp;
  5411 
  5412 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5413 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5414 
  5415 * AxClass.axclass_tac lost the theory argument;
  5416 
  5417 * tuned current_goals_markers semantics: begin / end goal avoids
  5418 printing empty lines;
  5419 
  5420 * removed prs and prs_fn hook, which was broken because it did not
  5421 include \n in its semantics, forcing writeln to add one
  5422 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5423 string -> unit if you really want to output text without newline;
  5424 
  5425 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5426 plain output, interface builders may have to enable 'isabelle_font'
  5427 mode to get Isabelle font glyphs as before;
  5428 
  5429 * refined token_translation interface; INCOMPATIBILITY: output length
  5430 now of type real instead of int;
  5431 
  5432 * theory loader actions may be traced via new ThyInfo.add_hook
  5433 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5434 your own database of information attached to *whole* theories -- as
  5435 opposed to intra-theory data slots offered via TheoryDataFun;
  5436 
  5437 * proper handling of dangling sort hypotheses (at last!);
  5438 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5439 extra sort hypotheses that can be witnessed from the type signature;
  5440 the force_strip_shyps flag is gone, any remaining shyps are simply
  5441 left in the theorem (with a warning issued by strip_shyps_warning);
  5442 
  5443 
  5444 
  5445 New in Isabelle98-1 (October 1998)
  5446 ----------------------------------
  5447 
  5448 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5449 
  5450 * several changes of automated proof tools;
  5451 
  5452 * HOL: major changes to the inductive and datatype packages, including
  5453 some minor incompatibilities of theory syntax;
  5454 
  5455 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5456 called `inj_on';
  5457 
  5458 * HOL: removed duplicate thms in Arith:
  5459   less_imp_add_less  should be replaced by  trans_less_add1
  5460   le_imp_add_le      should be replaced by  trans_le_add1
  5461 
  5462 * HOL: unary minus is now overloaded (new type constraints may be
  5463 required);
  5464 
  5465 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5466 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5467 now taken as an integer constant.
  5468 
  5469 * Pure: ML function 'theory_of' renamed to 'theory';
  5470 
  5471 
  5472 *** Proof tools ***
  5473 
  5474 * Simplifier:
  5475   1. Asm_full_simp_tac is now more aggressive.
  5476      1. It will sometimes reorient premises if that increases their power to
  5477         simplify.
  5478      2. It does no longer proceed strictly from left to right but may also
  5479         rotate premises to achieve further simplification.
  5480      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5481      old Asm_full_simp_tac in that it does not rotate premises.
  5482   2. The simplifier now knows a little bit about nat-arithmetic.
  5483 
  5484 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5485 allows for selected deletion of wrappers, by introduction of names for
  5486 wrapper functionals.  This implies that addbefore, addSbefore,
  5487 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5488 and that adding two tactics with the same name overwrites the first
  5489 one (emitting a warning).
  5490   type wrapper = (int -> tactic) -> (int -> tactic)
  5491   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5492   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5493   delWrapper, delSWrapper: claset *  string            -> claset
  5494   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5495 
  5496 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5497 semantics; addbefore now affects only the unsafe part of step_tac
  5498 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5499 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5500 by Force_tac;
  5501 
  5502 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5503 compWrapper; added safe wrapper (and access functions for it);
  5504 
  5505 * HOL/split_all_tac is now much faster and fails if there is nothing
  5506 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5507 and the names of the automatically generated variables have changed.
  5508 split_all_tac has moved within claset() from unsafe wrappers to safe
  5509 wrappers, which means that !!-bound variables are split much more
  5510 aggressively, and safe_tac and clarify_tac now split such variables.
  5511 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5512 Note: the same holds for record_split_tac, which does the job of
  5513 split_all_tac for record fields.
  5514 
  5515 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5516 permanently to the default simpset using Addsplits just like
  5517 Addsimps. They can be removed via Delsplits just like
  5518 Delsimps. Lower-case versions are also available.
  5519 
  5520 * HOL/Simplifier: The rule split_if is now part of the default
  5521 simpset. This means that the simplifier will eliminate all occurrences
  5522 of if-then-else in the conclusion of a goal. To prevent this, you can
  5523 either remove split_if completely from the default simpset by
  5524 `Delsplits [split_if]' or remove it in a specific call of the
  5525 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5526 other case splitting rules to/from the default simpset: every datatype
  5527 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5528 t is the name of the datatype).
  5529 
  5530 * Classical reasoner / Simplifier combination: new force_tac (and
  5531 derivatives Force_tac, force) combines rewriting and classical
  5532 reasoning (and whatever other tools) similarly to auto_tac, but is
  5533 aimed to solve the given subgoal completely.
  5534 
  5535 
  5536 *** General ***
  5537 
  5538 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5539 and `goalw': the theory is no longer needed as an explicit argument -
  5540 the current theory context is used; assumptions are no longer returned
  5541 at the ML-level unless one of them starts with ==> or !!; it is
  5542 recommended to convert to these new commands using isatool fixgoal
  5543 (backup your sources first!);
  5544 
  5545 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5546 the current theory context, and 'theory' to lookup stored theories;
  5547 
  5548 * new theory section 'locale' for declaring constants, assumptions and
  5549 definitions that have local scope;
  5550 
  5551 * new theory section 'nonterminals' for purely syntactic types;
  5552 
  5553 * new theory section 'setup' for generic ML setup functions
  5554 (e.g. package initialization);
  5555 
  5556 * the distribution now includes Isabelle icons: see
  5557 lib/logo/isabelle-{small,tiny}.xpm;
  5558 
  5559 * isatool install - install binaries with absolute references to
  5560 ISABELLE_HOME/bin;
  5561 
  5562 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5563 
  5564 * print mode 'emacs' reserved for Isamode;
  5565 
  5566 * support multiple print (ast) translations per constant name;
  5567 
  5568 * theorems involving oracles are now printed with a suffixed [!];
  5569 
  5570 
  5571 *** HOL ***
  5572 
  5573 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5574 
  5575 * HOL/inductive package reorganized and improved: now supports mutual
  5576 definitions such as
  5577 
  5578   inductive EVEN ODD
  5579     intrs
  5580       null "0 : EVEN"
  5581       oddI "n : EVEN ==> Suc n : ODD"
  5582       evenI "n : ODD ==> Suc n : EVEN"
  5583 
  5584 new theorem list "elims" contains an elimination rule for each of the
  5585 recursive sets; inductive definitions now handle disjunctive premises
  5586 correctly (also ZF);
  5587 
  5588 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5589 "mutual_induct" no longer exists - the induction rule is always
  5590 contained in "induct";
  5591 
  5592 
  5593 * HOL/datatype package re-implemented and greatly improved: now
  5594 supports mutually recursive datatypes such as
  5595 
  5596   datatype
  5597     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5598             | SUM ('a aexp) ('a aexp)
  5599             | DIFF ('a aexp) ('a aexp)
  5600             | NUM 'a
  5601   and
  5602     'a bexp = LESS ('a aexp) ('a aexp)
  5603             | AND ('a bexp) ('a bexp)
  5604             | OR ('a bexp) ('a bexp)
  5605 
  5606 as well as indirectly recursive datatypes such as
  5607 
  5608   datatype
  5609     ('a, 'b) term = Var 'a
  5610                   | App 'b ((('a, 'b) term) list)
  5611 
  5612 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5613 induction on mutually / indirectly recursive datatypes.
  5614 
  5615 Primrec equations are now stored in theory and can be accessed via
  5616 <function_name>.simps.
  5617 
  5618 INCOMPATIBILITIES:
  5619 
  5620   - Theories using datatypes must now have theory Datatype as an
  5621     ancestor.
  5622   - The specific <typename>.induct_tac no longer exists - use the
  5623     generic induct_tac instead.
  5624   - natE has been renamed to nat.exhaust - use exhaust_tac
  5625     instead of res_inst_tac ... natE. Note that the variable
  5626     names in nat.exhaust differ from the names in natE, this
  5627     may cause some "fragile" proofs to fail.
  5628   - The theorems split_<typename>_case and split_<typename>_case_asm
  5629     have been renamed to <typename>.split and <typename>.split_asm.
  5630   - Since default sorts of type variables are now handled correctly,
  5631     some datatype definitions may have to be annotated with explicit
  5632     sort constraints.
  5633   - Primrec definitions no longer require function name and type
  5634     of recursive argument.
  5635 
  5636 Consider using isatool fixdatatype to adapt your theories and proof
  5637 scripts to the new package (backup your sources first!).
  5638 
  5639 
  5640 * HOL/record package: considerably improved implementation; now
  5641 includes concrete syntax for record types, terms, updates; theorems
  5642 for surjective pairing and splitting !!-bound record variables; proof
  5643 support is as follows:
  5644 
  5645   1) standard conversions (selectors or updates applied to record
  5646 constructor terms) are part of the standard simpset;
  5647 
  5648   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5649 made part of standard simpset and claset via addIffs;
  5650 
  5651   3) a tactic for record field splitting (record_split_tac) is part of
  5652 the standard claset (addSWrapper);
  5653 
  5654 To get a better idea about these rules you may retrieve them via
  5655 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5656 the name of your record type.
  5657 
  5658 The split tactic 3) conceptually simplifies by the following rule:
  5659 
  5660   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5661 
  5662 Thus any record variable that is bound by meta-all will automatically
  5663 blow up into some record constructor term, consequently the
  5664 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5665 solve record problems automatically.
  5666 
  5667 
  5668 * reorganized the main HOL image: HOL/Integ and String loaded by
  5669 default; theory Main includes everything;
  5670 
  5671 * automatic simplification of integer sums and comparisons, using cancellation;
  5672 
  5673 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5674 
  5675 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5676 
  5677 * many new identities for unions, intersections, set difference, etc.;
  5678 
  5679 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5680 called split_if, split_split, split_sum_case and split_nat_case (to go
  5681 with add/delsplits);
  5682 
  5683 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5684 (?x::unit) = (); this is made part of the default simpset, which COULD
  5685 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5686 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5687 unit_abs_eta_conv is added in order to counter the effect of
  5688 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5689 %u.f();
  5690 
  5691 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5692 makes more sense);
  5693 
  5694 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5695   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5696   disjointness reasoning but breaking a few old proofs.
  5697 
  5698 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5699 to 'converse' from 'inverse' (for compatibility with ZF and some
  5700 literature);
  5701 
  5702 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5703 the well-founded relation;
  5704 
  5705 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5706     Compl A.  The "Compl" syntax remains available as input syntax for this
  5707     release ONLY.
  5708 
  5709 * HOL/Update: new theory of function updates:
  5710     f(a:=b) == %x. if x=a then b else f x
  5711 may also be iterated as in f(a:=b,c:=d,...);
  5712 
  5713 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5714 
  5715 * HOL/List:
  5716   - new function list_update written xs[i:=v] that updates the i-th
  5717     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5718   - new function `upt' written [i..j(] which generates the list
  5719     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5720     bound write [i..j], which is a shorthand for [i..j+1(].
  5721   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5722 
  5723 * HOL/Arith:
  5724   - removed 'pred' (predecessor) function;
  5725   - generalized some theorems about n-1;
  5726   - many new laws about "div" and "mod";
  5727   - new laws about greatest common divisors (see theory ex/Primes);
  5728 
  5729 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5730 instead of "inverse";
  5731 
  5732 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5733   of the multiset ordering;
  5734 
  5735 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5736   (not included by default);
  5737 
  5738 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5739 
  5740 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5741   programs, i.e. different program variables may have different types.
  5742 
  5743 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5744   [previously, this check worked only if the rewrite rule was unconditional]
  5745   Now rew can involve either definitions or equalities (either == or =).
  5746 
  5747 
  5748 *** ZF ***
  5749 
  5750 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5751   only the theorems proved on ZF.ML;
  5752 
  5753 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5754   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5755   disjointness reasoning but breaking a few old proofs.
  5756 
  5757 * ZF/Update: new theory of function updates
  5758     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5759   may also be iterated as in f(a:=b,c:=d,...);
  5760 
  5761 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5762 
  5763 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5764   [previously, this check worked only if the rewrite rule was unconditional]
  5765   Now rew can involve either definitions or equalities (either == or =).
  5766 
  5767 * case_tac provided for compatibility with HOL
  5768     (like the old excluded_middle_tac, but with subgoals swapped)
  5769 
  5770 
  5771 *** Internal programming interfaces ***
  5772 
  5773 * Pure: several new basic modules made available for general use, see
  5774 also src/Pure/README;
  5775 
  5776 * improved the theory data mechanism to support encapsulation (data
  5777 kind name replaced by private Object.kind, acting as authorization
  5778 key); new type-safe user interface via functor TheoryDataFun; generic
  5779 print_data function becomes basically useless;
  5780 
  5781 * removed global_names compatibility flag -- all theory declarations
  5782 are qualified by default;
  5783 
  5784 * module Pure/Syntax now offers quote / antiquote translation
  5785 functions (useful for Hoare logic etc. with implicit dependencies);
  5786 see HOL/ex/Antiquote for an example use;
  5787 
  5788 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5789 cterm -> thm;
  5790 
  5791 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5792 subgoal;
  5793 
  5794 * Display.print_goals function moved to Locale.print_goals;
  5795 
  5796 * standard print function for goals supports current_goals_markers
  5797 variable for marking begin of proof, end of proof, start of goal; the
  5798 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5799 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5800 for example;
  5801 
  5802 
  5803 
  5804 New in Isabelle98 (January 1998)
  5805 --------------------------------
  5806 
  5807 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5808 
  5809 * changed lexical syntax of terms / types: dots made part of long
  5810 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5811 
  5812 * simpset (and claset) reference variable replaced by functions
  5813 simpset / simpset_ref;
  5814 
  5815 * no longer supports theory aliases (via merge) and non-trivial
  5816 implicit merge of thms' signatures;
  5817 
  5818 * most internal names of constants changed due to qualified names;
  5819 
  5820 * changed Pure/Sequence interface (see Pure/seq.ML);
  5821 
  5822 
  5823 *** General Changes ***
  5824 
  5825 * hierachically structured name spaces (for consts, types, axms, thms
  5826 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5827 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5828 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5829 long_names for fully qualified output names; NOTE: ML programs
  5830 (special tactics, packages etc.) referring to internal names may have
  5831 to be adapted to cope with fully qualified names; in case of severe
  5832 backward campatibility problems try setting 'global_names' at compile
  5833 time to have enrything declared within a flat name space; one may also
  5834 fine tune name declarations in theories via the 'global' and 'local'
  5835 section;
  5836 
  5837 * reimplemented the implicit simpset and claset using the new anytype
  5838 data filed in signatures; references simpset:simpset ref etc. are
  5839 replaced by functions simpset:unit->simpset and
  5840 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5841 to patch your ML files accordingly;
  5842 
  5843 * HTML output now includes theory graph data for display with Java
  5844 applet or isatool browser; data generated automatically via isatool
  5845 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5846 
  5847 * defs may now be conditional; improved rewrite_goals_tac to handle
  5848 conditional equations;
  5849 
  5850 * defs now admits additional type arguments, using TYPE('a) syntax;
  5851 
  5852 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5853 creates a new theory node; implicit merge of thms' signatures is
  5854 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5855 transfer:theory->thm->thm in (rare) cases;
  5856 
  5857 * improved handling of draft signatures / theories; draft thms (and
  5858 ctyps, cterms) are automatically promoted to real ones;
  5859 
  5860 * slightly changed interfaces for oracles: admit many per theory, named
  5861 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5862 
  5863 * print_goals: optional output of const types (set show_consts and
  5864 show_types);
  5865 
  5866 * improved output of warnings (###) and errors (***);
  5867 
  5868 * subgoal_tac displays a warning if the new subgoal has type variables;
  5869 
  5870 * removed old README and Makefiles;
  5871 
  5872 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5873 
  5874 * removed obsolete init_pps and init_database;
  5875 
  5876 * deleted the obsolete tactical STATE, which was declared by
  5877     fun STATE tacfun st = tacfun st st;
  5878 
  5879 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5880 (which abbreviates $HOME);
  5881 
  5882 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5883 use isatool fixseq to adapt your ML programs (this works for fully
  5884 qualified references to the Sequence structure only!);
  5885 
  5886 * use_thy no longer requires writable current directory; it always
  5887 reloads .ML *and* .thy file, if either one is out of date;
  5888 
  5889 
  5890 *** Classical Reasoner ***
  5891 
  5892 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5893 tactics that use classical reasoning to simplify a subgoal without
  5894 splitting it into several subgoals;
  5895 
  5896 * Safe_tac: like safe_tac but uses the default claset;
  5897 
  5898 
  5899 *** Simplifier ***
  5900 
  5901 * added simplification meta rules:
  5902     (asm_)(full_)simplify: simpset -> thm -> thm;
  5903 
  5904 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5905 logics (again);
  5906 
  5907 * added prems argument to simplification procedures;
  5908 
  5909 * HOL, FOL, ZF: added infix function `addsplits':
  5910   instead of `<simpset> setloop (split_tac <thms>)'
  5911   you can simply write `<simpset> addsplits <thms>'
  5912 
  5913 
  5914 *** Syntax ***
  5915 
  5916 * TYPE('a) syntax for type reflection terms;
  5917 
  5918 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5919 
  5920 * pretty printer: changed order of mixfix annotation preference (again!);
  5921 
  5922 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5923 
  5924 
  5925 *** HOL ***
  5926 
  5927 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5928   with `addloop' of the simplifier to faciliate case splitting in premises.
  5929 
  5930 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5931 
  5932 * HOL/Auth: new protocol proofs including some for the Internet
  5933   protocol TLS;
  5934 
  5935 * HOL/Map: new theory of `maps' a la VDM;
  5936 
  5937 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5938 cancelling out common nat summands from =, <, <= (in)equalities, or
  5939 differences; simplification procedures nat_cancel_factor for
  5940 cancelling common factor from =, <, <= (in)equalities over natural
  5941 sums; nat_cancel contains both kinds of procedures, it is installed by
  5942 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5943 
  5944 * HOL/simplifier: terms of the form
  5945   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5946   are rewritten to
  5947   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5948   and those of the form
  5949   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5950   are rewritten to
  5951   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5952 
  5953 * HOL/datatype
  5954   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5955 
  5956   P(t_case f1 ... fn x) =
  5957      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5958         ...
  5959        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5960      )
  5961 
  5962   and a theorem `split_t_case_asm' of the form
  5963 
  5964   P(t_case f1 ... fn x) =
  5965     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5966         ...
  5967        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5968      )
  5969   which can be added to a simpset via `addsplits'. The existing theorems
  5970   expand_list_case and expand_option_case have been renamed to
  5971   split_list_case and split_option_case.
  5972 
  5973 * HOL/Arithmetic:
  5974   - `pred n' is automatically converted to `n-1'.
  5975     Users are strongly encouraged not to use `pred' any longer,
  5976     because it will disappear altogether at some point.
  5977   - Users are strongly encouraged to write "0 < n" rather than
  5978     "n ~= 0". Theorems and proof tools have been modified towards this
  5979     `standard'.
  5980 
  5981 * HOL/Lists:
  5982   the function "set_of_list" has been renamed "set" (and its theorems too);
  5983   the function "nth" now takes its arguments in the reverse order and
  5984   has acquired the infix notation "!" as in "xs!n".
  5985 
  5986 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5987 
  5988 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5989   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5990 
  5991 * HOL/record: extensible records with schematic structural subtyping
  5992 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5993 still lacks various theorems and concrete record syntax;
  5994 
  5995 
  5996 *** HOLCF ***
  5997 
  5998 * removed "axioms" and "generated by" sections;
  5999 
  6000 * replaced "ops" section by extended "consts" section, which is capable of
  6001   handling the continuous function space "->" directly;
  6002 
  6003 * domain package:
  6004   . proves theorems immediately and stores them in the theory,
  6005   . creates hierachical name space,
  6006   . now uses normal mixfix annotations (instead of cinfix...),
  6007   . minor changes to some names and values (for consistency),
  6008   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  6009   . separator between mutual domain defs: changed "," to "and",
  6010   . improved handling of sort constraints;  now they have to
  6011     appear on the left-hand side of the equations only;
  6012 
  6013 * fixed LAM <x,y,zs>.b syntax;
  6014 
  6015 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  6016 adm (%x. P (t x)), where P is chainfinite and t continuous;
  6017 
  6018 
  6019 *** FOL and ZF ***
  6020 
  6021 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6022   with `addloop' of the simplifier to faciliate case splitting in premises.
  6023 
  6024 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6025 in HOL, they strip ALL and --> from proved theorems;
  6026 
  6027 
  6028 
  6029 New in Isabelle94-8 (May 1997)
  6030 ------------------------------
  6031 
  6032 *** General Changes ***
  6033 
  6034 * new utilities to build / run / maintain Isabelle etc. (in parts
  6035 still somewhat experimental); old Makefiles etc. still functional;
  6036 
  6037 * new 'Isabelle System Manual';
  6038 
  6039 * INSTALL text, together with ./configure and ./build scripts;
  6040 
  6041 * reimplemented type inference for greater efficiency, better error
  6042 messages and clean internal interface;
  6043 
  6044 * prlim command for dealing with lots of subgoals (an easier way of
  6045 setting goals_limit);
  6046 
  6047 
  6048 *** Syntax ***
  6049 
  6050 * supports alternative (named) syntax tables (parser and pretty
  6051 printer); internal interface is provided by add_modesyntax(_i);
  6052 
  6053 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6054 be used in conjunction with the Isabelle symbol font; uses the
  6055 "symbols" syntax table;
  6056 
  6057 * added token_translation interface (may translate name tokens in
  6058 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6059 the current print_mode); IMPORTANT: user print translation functions
  6060 are responsible for marking newly introduced bounds
  6061 (Syntax.mark_boundT);
  6062 
  6063 * token translations for modes "xterm" and "xterm_color" that display
  6064 names in bold, underline etc. or colors (which requires a color
  6065 version of xterm);
  6066 
  6067 * infixes may now be declared with names independent of their syntax;
  6068 
  6069 * added typed_print_translation (like print_translation, but may
  6070 access type of constant);
  6071 
  6072 
  6073 *** Classical Reasoner ***
  6074 
  6075 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6076 some limitations.  Blast_tac...
  6077   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6078   + ignores elimination rules that don't have the correct format
  6079         (the conclusion MUST be a formula variable)
  6080   + ignores types, which can make HOL proofs fail
  6081   + rules must not require higher-order unification, e.g. apply_type in ZF
  6082     [message "Function Var's argument not a bound variable" relates to this]
  6083   + its proof strategy is more general but can actually be slower
  6084 
  6085 * substitution with equality assumptions no longer permutes other
  6086 assumptions;
  6087 
  6088 * minor changes in semantics of addafter (now called addaltern); renamed
  6089 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6090 (and access functions for it);
  6091 
  6092 * improved combination of classical reasoner and simplifier:
  6093   + functions for handling clasimpsets
  6094   + improvement of addss: now the simplifier is called _after_ the
  6095     safe steps.
  6096   + safe variant of addss called addSss: uses safe simplifications
  6097     _during_ the safe steps. It is more complete as it allows multiple
  6098     instantiations of unknowns (e.g. with slow_tac).
  6099 
  6100 *** Simplifier ***
  6101 
  6102 * added interface for simplification procedures (functions that
  6103 produce *proven* rewrite rules on the fly, depending on current
  6104 redex);
  6105 
  6106 * ordering on terms as parameter (used for ordered rewriting);
  6107 
  6108 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6109 
  6110 * the solver is now split into a safe and an unsafe part.
  6111 This should be invisible for the normal user, except that the
  6112 functions setsolver and addsolver have been renamed to setSolver and
  6113 addSolver; added safe_asm_full_simp_tac;
  6114 
  6115 
  6116 *** HOL ***
  6117 
  6118 * a generic induction tactic `induct_tac' which works for all datatypes and
  6119 also for type `nat';
  6120 
  6121 * a generic case distinction tactic `exhaust_tac' which works for all
  6122 datatypes and also for type `nat';
  6123 
  6124 * each datatype comes with a function `size';
  6125 
  6126 * patterns in case expressions allow tuple patterns as arguments to
  6127 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6128 
  6129 * primrec now also works with type nat;
  6130 
  6131 * recdef: a new declaration form, allows general recursive functions to be
  6132 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6133 
  6134 * the constant for negation has been renamed from "not" to "Not" to
  6135 harmonize with FOL, ZF, LK, etc.;
  6136 
  6137 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6138 infinite lists;
  6139 
  6140 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6141 
  6142 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6143 problems in commutative rings, using axiomatic type classes for + and *;
  6144 
  6145 * more examples in HOL/MiniML and HOL/Auth;
  6146 
  6147 * more default rewrite rules for quantifiers, union/intersection;
  6148 
  6149 * a new constant `arbitrary == @x.False';
  6150 
  6151 * HOLCF/IOA replaces old HOL/IOA;
  6152 
  6153 * HOLCF changes: derived all rules and arities
  6154   + axiomatic type classes instead of classes
  6155   + typedef instead of faking type definitions
  6156   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6157   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6158   + eliminated the types void, one, tr
  6159   + use unit lift and bool lift (with translations) instead of one and tr
  6160   + eliminated blift from Lift3.thy (use Def instead of blift)
  6161   all eliminated rules are derived as theorems --> no visible changes ;
  6162 
  6163 
  6164 *** ZF ***
  6165 
  6166 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6167 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6168 as ZF_cs addSIs [equalityI];
  6169 
  6170 
  6171 
  6172 New in Isabelle94-7 (November 96)
  6173 ---------------------------------
  6174 
  6175 * allowing negative levels (as offsets) in prlev and choplev;
  6176 
  6177 * super-linear speedup for large simplifications;
  6178 
  6179 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6180 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6181 FAIL); can suppress it using the command Delsimps (ex_simps @
  6182 all_simps); De Morgan laws are also now included, by default;
  6183 
  6184 * improved printing of ==>  :  ~:
  6185 
  6186 * new object-logic "Sequents" adds linear logic, while replacing LK
  6187 and Modal (thanks to Sara Kalvala);
  6188 
  6189 * HOL/Auth: correctness proofs for authentication protocols;
  6190 
  6191 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6192 examples on HOL/Auth);
  6193 
  6194 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6195 the rewriter and classical reasoner simultaneously;
  6196 
  6197 * function uresult no longer returns theorems in "standard" format;
  6198 regain previous version by: val uresult = standard o uresult;
  6199 
  6200 
  6201 
  6202 New in Isabelle94-6
  6203 -------------------
  6204 
  6205 * oracles -- these establish an interface between Isabelle and trusted
  6206 external reasoners, which may deliver results as theorems;
  6207 
  6208 * proof objects (in particular record all uses of oracles);
  6209 
  6210 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6211 
  6212 * "constdefs" section in theory files;
  6213 
  6214 * "primrec" section (HOL) no longer requires names;
  6215 
  6216 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6217 
  6218 
  6219 
  6220 New in Isabelle94-5
  6221 -------------------
  6222 
  6223 * reduced space requirements;
  6224 
  6225 * automatic HTML generation from theories;
  6226 
  6227 * theory files no longer require "..." (quotes) around most types;
  6228 
  6229 * new examples, including two proofs of the Church-Rosser theorem;
  6230 
  6231 * non-curried (1994) version of HOL is no longer distributed;
  6232 
  6233 
  6234 
  6235 New in Isabelle94-4
  6236 -------------------
  6237 
  6238 * greatly reduced space requirements;
  6239 
  6240 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6241 
  6242 * searchable theorem database (see the section "Retrieving theorems" on
  6243 page 8 of the Reference Manual);
  6244 
  6245 * new examples, including Grabczewski's monumental case study of the
  6246 Axiom of Choice;
  6247 
  6248 * The previous version of HOL renamed to Old_HOL;
  6249 
  6250 * The new version of HOL (previously called CHOL) uses a curried syntax
  6251 for functions.  Application looks like f a b instead of f(a,b);
  6252 
  6253 * Mutually recursive inductive definitions finally work in HOL;
  6254 
  6255 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6256 translates to the operator "split";
  6257 
  6258 
  6259 
  6260 New in Isabelle94-3
  6261 -------------------
  6262