NEWS
author haftmann
Mon Jun 15 16:13:19 2009 +0200 (2009-06-15)
changeset 31643 b040f1679f77
parent 31626 fe35b72b9ef0
child 31720 d1ac3f3b2f54
child 31723 f5cafe803b55
permissions -rw-r--r--
authentic syntax for Pow and image
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Discontinued old form of "escaped symbols" such as \\<forall>.  Only
    10 one backslash should be used, even in ML sources.
    11 
    12 
    13 *** Pure ***
    14 
    15 * On instantiation of classes, remaining undefined class parameters
    16 are formally declared.  INCOMPATIBILITY.
    17 
    18 
    19 *** HOL ***
    20 
    21 * Class semiring_div requires superclass no_zero_divisors and proof of
    22 div_mult_mult1; theorems div_mult_mult1, div_mult_mult2,
    23 div_mult_mult1_if, div_mult_mult1 and div_mult_mult2 have been
    24 generalized to class semiring_div, subsuming former theorems
    25 zdiv_zmult_zmult1, zdiv_zmult_zmult1_if, zdiv_zmult_zmult1 and
    26 zdiv_zmult_zmult2.  div_mult_mult1 is now [simp] by default.
    27 INCOMPATIBILITY.
    28 
    29 * Power operations on relations and functions are now one dedicate
    30 constant compow with infix syntax "^^".  Power operations on
    31 multiplicative monoids retains syntax "^" and is now defined generic
    32 in class power.  INCOMPATIBILITY.
    33 
    34 * ML antiquotation @{code_datatype} inserts definition of a datatype
    35 generated by the code generator; see Predicate.thy for an example.
    36 
    37 * New method "linarith" invokes existing linear arithmetic decision
    38 procedure only.
    39 
    40 * Implementation of quickcheck using generic code generator; default generators
    41 are provided for all suitable HOL types, records and datatypes.
    42 
    43 * Constants Set.Pow and Set.image now with authentic syntax; object-logic definitions
    44 Set.Pow_def and Set.image_def.  INCOMPATIBILITY.
    45 
    46 
    47 *** ML ***
    48 
    49 * Eliminated old Attrib.add_attributes, Method.add_methods and related
    50 cominators for "args".  INCOMPATIBILITY, need to use simplified
    51 Attrib/Method.setup introduced in Isabelle2009.
    52 
    53 
    54 *** System ***
    55 
    56 * Discontinued support for Poly/ML 4.x versions.
    57 
    58 * Removed "compress" option from isabelle-process and isabelle usedir;
    59 this is always enabled.
    60 
    61 
    62 
    63 New in Isabelle2009 (April 2009)
    64 --------------------------------
    65 
    66 *** General ***
    67 
    68 * Simplified main Isabelle executables, with less surprises on
    69 case-insensitive file-systems (such as Mac OS).
    70 
    71   - The main Isabelle tool wrapper is now called "isabelle" instead of
    72     "isatool."
    73 
    74   - The former "isabelle" alias for "isabelle-process" has been
    75     removed (should rarely occur to regular users).
    76 
    77   - The former "isabelle-interface" and its alias "Isabelle" have been
    78     removed (interfaces are now regular Isabelle tools).
    79 
    80 Within scripts and make files, the Isabelle environment variables
    81 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    82 respectively.  (The latter are still available as legacy feature.)
    83 
    84 The old isabelle-interface wrapper could react in confusing ways if
    85 the interface was uninstalled or changed otherwise.  Individual
    86 interface tool configuration is now more explicit, see also the
    87 Isabelle system manual.  In particular, Proof General is now available
    88 via "isabelle emacs".
    89 
    90 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    91 purge installed copies of Isabelle executables and re-run "isabelle
    92 install -p ...", or use symlinks.
    93 
    94 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    95 old ~/isabelle, which was slightly non-standard and apt to cause
    96 surprises on case-insensitive file-systems (such as Mac OS).
    97 
    98 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    99 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
   100 care is required when using older releases of Isabelle.  Note that
   101 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
   102 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
   103 
   104 * Proofs of fully specified statements are run in parallel on
   105 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
   106 a regular 4-core machine, if the initial heap space is made reasonably
   107 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
   108 
   109 * The main reference manuals ("isar-ref", "implementation", and
   110 "system") have been updated and extended.  Formally checked references
   111 as hyperlinks are now available uniformly.
   112 
   113 
   114 *** Pure ***
   115 
   116 * Complete re-implementation of locales.  INCOMPATIBILITY in several
   117 respects.  The most important changes are listed below.  See the
   118 Tutorial on Locales ("locales" manual) for details.
   119 
   120 - In locale expressions, instantiation replaces renaming.  Parameters
   121 must be declared in a for clause.  To aid compatibility with previous
   122 parameter inheritance, in locale declarations, parameters that are not
   123 'touched' (instantiation position "_" or omitted) are implicitly added
   124 with their syntax at the beginning of the for clause.
   125 
   126 - Syntax from abbreviations and definitions in locales is available in
   127 locale expressions and context elements.  The latter is particularly
   128 useful in locale declarations.
   129 
   130 - More flexible mechanisms to qualify names generated by locale
   131 expressions.  Qualifiers (prefixes) may be specified in locale
   132 expressions, and can be marked as mandatory (syntax: "name!:") or
   133 optional (syntax "name?:").  The default depends for plain "name:"
   134 depends on the situation where a locale expression is used: in
   135 commands 'locale' and 'sublocale' prefixes are optional, in
   136 'interpretation' and 'interpret' prefixes are mandatory.  The old
   137 implicit qualifiers derived from the parameter names of a locale are
   138 no longer generated.
   139 
   140 - Command "sublocale l < e" replaces "interpretation l < e".  The
   141 instantiation clause in "interpretation" and "interpret" (square
   142 brackets) is no longer available.  Use locale expressions.
   143 
   144 - When converting proof scripts, mandatory qualifiers in
   145 'interpretation' and 'interpret' should be retained by default, even
   146 if this is an INCOMPATIBILITY compared to former behavior.  In the
   147 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   148 in locale expressions range over a single locale instance only.
   149 
   150 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   151 In existing theorem specifications replace the includes element by the
   152 respective context elements of the included locale, omitting those
   153 that are already present in the theorem specification.  Multiple
   154 assume elements of a locale should be replaced by a single one
   155 involving the locale predicate.  In the proof body, declarations (most
   156 notably theorems) may be regained by interpreting the respective
   157 locales in the proof context as required (command "interpret").
   158 
   159 If using "includes" in replacement of a target solely because the
   160 parameter types in the theorem are not as general as in the target,
   161 consider declaring a new locale with additional type constraints on
   162 the parameters (context element "constrains").
   163 
   164 - Discontinued "locale (open)".  INCOMPATIBILITY.
   165 
   166 - Locale interpretation commands no longer attempt to simplify goal.
   167 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   168 methods intro_locales and unfold_locales to clarify.
   169 
   170 - Locale interpretation commands no longer accept interpretation
   171 attributes.  INCOMPATIBILITY.
   172 
   173 * Class declaration: so-called "base sort" must not be given in import
   174 list any longer, but is inferred from the specification.  Particularly
   175 in HOL, write
   176 
   177     class foo = ...
   178 
   179 instead of
   180 
   181     class foo = type + ...
   182 
   183 * Class target: global versions of theorems stemming do not carry a
   184 parameter prefix any longer.  INCOMPATIBILITY.
   185 
   186 * Class 'instance' command no longer accepts attached definitions.
   187 INCOMPATIBILITY, use proper 'instantiation' target instead.
   188 
   189 * Recovered hiding of consts, which was accidentally broken in
   190 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   191 makes c inaccessible; consider using ``hide (open) const c'' instead.
   192 
   193 * Slightly more coherent Pure syntax, with updated documentation in
   194 isar-ref manual.  Removed locales meta_term_syntax and
   195 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   196 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   197 directly in regular applications.
   198 
   199 * There is a new syntactic category "float_const" for signed decimal
   200 fractions (e.g. 123.45 or -123.45).
   201 
   202 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   203 interface with 'setup' command instead.
   204 
   205 * Command 'local_setup' is similar to 'setup', but operates on a local
   206 theory context.
   207 
   208 * The 'axiomatization' command now only works within a global theory
   209 context.  INCOMPATIBILITY.
   210 
   211 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   212 hypotheses.  Sorts required in the course of reasoning need to be
   213 covered by the constraints in the initial statement, completed by the
   214 type instance information of the background theory.  Non-trivial sort
   215 hypotheses, which rarely occur in practice, may be specified via
   216 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   217 
   218   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   219 
   220 The result contains an implicit sort hypotheses as before --
   221 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   222 normalization.
   223 
   224 * Generalized Isar history, with support for linear undo, direct state
   225 addressing etc.
   226 
   227 * Changed defaults for unify configuration options:
   228 
   229   unify_trace_bound = 50 (formerly 25)
   230   unify_search_bound = 60 (formerly 30)
   231 
   232 * Different bookkeeping for code equations (INCOMPATIBILITY):
   233 
   234   a) On theory merge, the last set of code equations for a particular
   235      constant is taken (in accordance with the policy applied by other
   236      parts of the code generator framework).
   237 
   238   b) Code equations stemming from explicit declarations (e.g. code
   239      attribute) gain priority over default code equations stemming
   240      from definition, primrec, fun etc.
   241 
   242 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   243 
   244 * Unified theorem tables for both code generators.  Thus [code
   245 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   246 
   247 * Command 'find_consts' searches for constants based on type and name
   248 patterns, e.g.
   249 
   250     find_consts "_ => bool"
   251 
   252 By default, matching is against subtypes, but it may be restricted to
   253 the whole type.  Searching by name is possible.  Multiple queries are
   254 conjunctive and queries may be negated by prefixing them with a
   255 hyphen:
   256 
   257     find_consts strict: "_ => bool" name: "Int" -"int => int"
   258 
   259 * New 'find_theorems' criterion "solves" matches theorems that
   260 directly solve the current goal (modulo higher-order unification).
   261 
   262 * Auto solve feature for main theorem statements: whenever a new goal
   263 is stated, "find_theorems solves" is called; any theorems that could
   264 solve the lemma directly are listed as part of the goal state.
   265 Cf. associated options in Proof General Isabelle settings menu,
   266 enabled by default, with reasonable timeout for pathological cases of
   267 higher-order unification.
   268 
   269 
   270 *** Document preparation ***
   271 
   272 * Antiquotation @{lemma} now imitates a regular terminal proof,
   273 demanding keyword 'by' and supporting the full method expression
   274 syntax just like the Isar command 'by'.
   275 
   276 
   277 *** HOL ***
   278 
   279 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   280 points Main and Complex_Main remain as before.
   281 
   282 * Logic image HOL-Plain provides a minimal HOL with the most important
   283 tools available (inductive, datatype, primrec, ...).  This facilitates
   284 experimentation and tool development.  Note that user applications
   285 (and library theories) should never refer to anything below theory
   286 Main, as before.
   287 
   288 * Logic image HOL-Main stops at theory Main, and thus facilitates
   289 experimentation due to shorter build times.
   290 
   291 * Logic image HOL-NSA contains theories of nonstandard analysis which
   292 were previously part of former HOL-Complex.  Entry point Hyperreal
   293 remains valid, but theories formerly using Complex_Main should now use
   294 new entry point Hypercomplex.
   295 
   296 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   297 Posix processes.  Avoids potentially expensive forking of the ML
   298 process.  New thread-based implementation also works on non-Unix
   299 platforms (Cygwin).  Provers are no longer hardwired, but defined
   300 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   301 commands are covered in the isar-ref manual.
   302 
   303 * Wrapper scripts for remote SystemOnTPTP service allows to use
   304 sledgehammer without local ATP installation (Vampire etc.). Other
   305 provers may be included via suitable ML wrappers, see also
   306 src/HOL/ATP_Linkup.thy.
   307 
   308 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   309 menu.
   310 
   311 * The metis method no longer fails because the theorem is too trivial
   312 (contains the empty clause).
   313 
   314 * The metis method now fails in the usual manner, rather than raising
   315 an exception, if it determines that it cannot prove the theorem.
   316 
   317 * Method "coherent" implements a prover for coherent logic (see also
   318 src/Tools/coherent.ML).
   319 
   320 * Constants "undefined" and "default" replace "arbitrary".  Usually
   321 "undefined" is the right choice to replace "arbitrary", though
   322 logically there is no difference.  INCOMPATIBILITY.
   323 
   324 * Command "value" now integrates different evaluation mechanisms.  The
   325 result of the first successful evaluation mechanism is printed.  In
   326 square brackets a particular named evaluation mechanisms may be
   327 specified (currently, [SML], [code] or [nbe]).  See further
   328 src/HOL/ex/Eval_Examples.thy.
   329 
   330 * Normalization by evaluation now allows non-leftlinear equations.
   331 Declare with attribute [code nbe].
   332 
   333 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   334 as the structured Isar versions "cases" and "induct", cf. the
   335 corresponding "cases" and "induct" attributes.  Mutual induction rules
   336 are now presented as a list of individual projections
   337 (e.g. foo_bar.inducts for types foo and bar); the old format with
   338 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   339 rare situations a different rule is selected --- notably nested tuple
   340 elimination instead of former prod.exhaust: use explicit (case_tac t
   341 rule: prod.exhaust) here.
   342 
   343 * Attributes "cases", "induct", "coinduct" support "del" option.
   344 
   345 * Removed fact "case_split_thm", which duplicates "case_split".
   346 
   347 * The option datatype has been moved to a new theory Option.  Renamed
   348 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   349 
   350 * New predicate "strict_mono" classifies strict functions on partial
   351 orders.  With strict functions on linear orders, reasoning about
   352 (in)equalities is facilitated by theorems "strict_mono_eq",
   353 "strict_mono_less_eq" and "strict_mono_less".
   354 
   355 * Some set operations are now proper qualified constants with
   356 authentic syntax.  INCOMPATIBILITY:
   357 
   358     op Int ~>   Set.Int
   359     op Un ~>    Set.Un
   360     INTER ~>    Set.INTER
   361     UNION ~>    Set.UNION
   362     Inter ~>    Set.Inter
   363     Union ~>    Set.Union
   364     {} ~>       Set.empty
   365     UNIV ~>     Set.UNIV
   366 
   367 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   368 theory Set.
   369 
   370 * Auxiliary class "itself" has disappeared -- classes without any
   371 parameter are treated as expected by the 'class' command.
   372 
   373 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   374 
   375 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   376 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   377 
   378 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   379 method "approximation".  It proves formulas on real values by using
   380 interval arithmetic.  In the formulas are also the transcendental
   381 functions sin, cos, tan, atan, ln, exp and the constant pi are
   382 allowed. For examples see
   383 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   384 
   385 * Theory "Reflection" now resides in HOL/Library.
   386 
   387 * Entry point to Word library now simply named "Word".
   388 INCOMPATIBILITY.
   389 
   390 * Made source layout more coherent with logical distribution
   391 structure:
   392 
   393     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   394     src/HOL/Library/Code_Message.thy ~> src/HOL/
   395     src/HOL/Library/GCD.thy ~> src/HOL/
   396     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   397     src/HOL/Library/Parity.thy ~> src/HOL/
   398     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   399     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   400     src/HOL/Real/Lubs.thy ~> src/HOL/
   401     src/HOL/Real/PReal.thy ~> src/HOL/
   402     src/HOL/Real/Rational.thy ~> src/HOL/
   403     src/HOL/Real/RComplete.thy ~> src/HOL/
   404     src/HOL/Real/RealDef.thy ~> src/HOL/
   405     src/HOL/Real/RealPow.thy ~> src/HOL/
   406     src/HOL/Real/Real.thy ~> src/HOL/
   407     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   408     src/HOL/Complex/Complex.thy ~> src/HOL/
   409     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   410     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   411     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   412     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   413     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   414     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   415     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   416     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   417     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   418     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   419     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   420     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   421     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   422     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   423     src/HOL/Real/Float ~> src/HOL/Library/
   424     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   425     src/HOL/Real/RealVector.thy ~> src/HOL/
   426 
   427     src/HOL/arith_data.ML ~> src/HOL/Tools
   428     src/HOL/hologic.ML ~> src/HOL/Tools
   429     src/HOL/simpdata.ML ~> src/HOL/Tools
   430     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   431     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   432     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   433     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   434     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   435     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   436     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   437 
   438     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   439     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   440     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   441     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   442     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   443     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   444 
   445 * If methods "eval" and "evaluation" encounter a structured proof
   446 state with !!/==>, only the conclusion is evaluated to True (if
   447 possible), avoiding strange error messages.
   448 
   449 * Method "sizechange" automates termination proofs using (a
   450 modification of) the size-change principle.  Requires SAT solver.  See
   451 src/HOL/ex/Termination.thy for examples.
   452 
   453 * Simplifier: simproc for let expressions now unfolds if bound
   454 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   455 
   456 * Method "arith": Linear arithmetic now ignores all inequalities when
   457 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   458 
   459 * New attribute "arith" for facts that should always be used
   460 automatically by arithmetic. It is intended to be used locally in
   461 proofs, e.g.
   462 
   463   assumes [arith]: "x > 0"
   464 
   465 Global usage is discouraged because of possible performance impact.
   466 
   467 * New classes "top" and "bot" with corresponding operations "top" and
   468 "bot" in theory Orderings; instantiation of class "complete_lattice"
   469 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   470 
   471 * Changed definition lemma "less_fun_def" in order to provide an
   472 instance for preorders on functions; use lemma "less_le" instead.
   473 INCOMPATIBILITY.
   474 
   475 * Theory Orderings: class "wellorder" moved here, with explicit
   476 induction rule "less_induct" as assumption.  For instantiation of
   477 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   478 INCOMPATIBILITY.
   479 
   480 * Theory Orderings: added class "preorder" as superclass of "order".
   481 INCOMPATIBILITY: Instantiation proofs for order, linorder
   482 etc. slightly changed.  Some theorems named order_class.* now named
   483 preorder_class.*.
   484 
   485 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   486 "diag" to "Id_on".
   487 
   488 * Theory Finite_Set: added a new fold combinator of type
   489 
   490   ('a => 'b => 'b) => 'b => 'a set => 'b
   491 
   492 Occasionally this is more convenient than the old fold combinator
   493 which is now defined in terms of the new one and renamed to
   494 fold_image.
   495 
   496 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   497 and "ring_simps" have been replaced by "algebra_simps" (which can be
   498 extended with further lemmas!).  At the moment both still exist but
   499 the former will disappear at some point.
   500 
   501 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   502 class recpower.  Type-specific simp rules for various recpower types
   503 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   504 
   505 rat_power_0    -> power_0
   506 rat_power_Suc  -> power_Suc
   507 realpow_0      -> power_0
   508 realpow_Suc    -> power_Suc
   509 complexpow_0   -> power_0
   510 complexpow_Suc -> power_Suc
   511 power_poly_0   -> power_0
   512 power_poly_Suc -> power_Suc
   513 
   514 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   515 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   516 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   517 of lemmas from Divides has been generalized from nat to class
   518 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   519 renames resulting from duplicate elimination:
   520 
   521     dvd_def_mod ~>          dvd_eq_mod_eq_0
   522     zero_dvd_iff ~>         dvd_0_left_iff
   523     dvd_0 ~>                dvd_0_right
   524     DIVISION_BY_ZERO_DIV ~> div_by_0
   525     DIVISION_BY_ZERO_MOD ~> mod_by_0
   526     mult_div ~>             div_mult_self2_is_id
   527     mult_mod ~>             mod_mult_self2_is_0
   528 
   529 * Theory IntDiv: removed many lemmas that are instances of class-based
   530 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   531 rename old lemmas as follows:
   532 
   533 dvd_diff               -> nat_dvd_diff
   534 dvd_zminus_iff         -> dvd_minus_iff
   535 mod_add1_eq            -> mod_add_eq
   536 mod_mult1_eq           -> mod_mult_right_eq
   537 mod_mult1_eq'          -> mod_mult_left_eq
   538 mod_mult_distrib_mod   -> mod_mult_eq
   539 nat_mod_add_left_eq    -> mod_add_left_eq
   540 nat_mod_add_right_eq   -> mod_add_right_eq
   541 nat_mod_div_trivial    -> mod_div_trivial
   542 nat_mod_mod_trivial    -> mod_mod_trivial
   543 zdiv_zadd_self1        -> div_add_self1
   544 zdiv_zadd_self2        -> div_add_self2
   545 zdiv_zmult_self1       -> div_mult_self2_is_id
   546 zdiv_zmult_self2       -> div_mult_self1_is_id
   547 zdvd_triv_left         -> dvd_triv_left
   548 zdvd_triv_right        -> dvd_triv_right
   549 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   550 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   551 zmod_zadd_left_eq      -> mod_add_left_eq
   552 zmod_zadd_right_eq     -> mod_add_right_eq
   553 zmod_zadd_self1        -> mod_add_self1
   554 zmod_zadd_self2        -> mod_add_self2
   555 zmod_zadd1_eq          -> mod_add_eq
   556 zmod_zdiff1_eq         -> mod_diff_eq
   557 zmod_zdvd_zmod         -> mod_mod_cancel
   558 zmod_zmod_cancel       -> mod_mod_cancel
   559 zmod_zmult_self1       -> mod_mult_self2_is_0
   560 zmod_zmult_self2       -> mod_mult_self1_is_0
   561 zmod_1                 -> mod_by_1
   562 zdiv_1                 -> div_by_1
   563 zdvd_abs1              -> abs_dvd_iff
   564 zdvd_abs2              -> dvd_abs_iff
   565 zdvd_refl              -> dvd_refl
   566 zdvd_trans             -> dvd_trans
   567 zdvd_zadd              -> dvd_add
   568 zdvd_zdiff             -> dvd_diff
   569 zdvd_zminus_iff        -> dvd_minus_iff
   570 zdvd_zminus2_iff       -> minus_dvd_iff
   571 zdvd_zmultD            -> dvd_mult_right
   572 zdvd_zmultD2           -> dvd_mult_left
   573 zdvd_zmult_mono        -> mult_dvd_mono
   574 zdvd_0_right           -> dvd_0_right
   575 zdvd_0_left            -> dvd_0_left_iff
   576 zdvd_1_left            -> one_dvd
   577 zminus_dvd_iff         -> minus_dvd_iff
   578 
   579 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   580 
   581 * The real numbers offer decimal input syntax: 12.34 is translated
   582 into 1234/10^2. This translation is not reversed upon output.
   583 
   584 * Theory Library/Polynomial defines an abstract type 'a poly of
   585 univariate polynomials with coefficients of type 'a.  In addition to
   586 the standard ring operations, it also supports div and mod.  Code
   587 generation is also supported, using list-style constructors.
   588 
   589 * Theory Library/Inner_Product defines a class of real_inner for real
   590 inner product spaces, with an overloaded operation inner :: 'a => 'a
   591 => real.  Class real_inner is a subclass of real_normed_vector from
   592 theory RealVector.
   593 
   594 * Theory Library/Product_Vector provides instances for the product
   595 type 'a * 'b of several classes from RealVector and Inner_Product.
   596 Definitions of addition, subtraction, scalar multiplication, norms,
   597 and inner products are included.
   598 
   599 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   600 addition to the field operations, numerals and case syntax are also
   601 supported.
   602 
   603 * Theory Library/Diagonalize provides constructive version of Cantor's
   604 first diagonalization argument.
   605 
   606 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   607 zlcm (for int); carried together from various gcd/lcm developements in
   608 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   609 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   610 may recover tupled syntax as follows:
   611 
   612     hide (open) const gcd
   613     abbreviation gcd where
   614       "gcd == (%(a, b). GCD.gcd a b)"
   615     notation (output)
   616       GCD.gcd ("gcd '(_, _')")
   617 
   618 The same works for lcm, zgcd, zlcm.
   619 
   620 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   621 instantiations for algebraic structures.  Removed some duplicate
   622 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   623 
   624 * ML antiquotation @{code} takes a constant as argument and generates
   625 corresponding code in background and inserts name of the corresponding
   626 resulting ML value/function/datatype constructor binding in place.
   627 All occurrences of @{code} with a single ML block are generated
   628 simultaneously.  Provides a generic and safe interface for
   629 instrumentalizing code generation.  See
   630 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   631 In future you ought to refrain from ad-hoc compiling generated SML
   632 code on the ML toplevel.  Note that (for technical reasons) @{code}
   633 cannot refer to constants for which user-defined serializations are
   634 set.  Refer to the corresponding ML counterpart directly in that
   635 cases.
   636 
   637 * Command 'rep_datatype': instead of theorem names the command now
   638 takes a list of terms denoting the constructors of the type to be
   639 represented as datatype.  The characteristic theorems have to be
   640 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   641 have disappeared in favour of existing ones:
   642 
   643     unit_induct                 ~> unit.induct
   644     prod_induct                 ~> prod.induct
   645     sum_induct                  ~> sum.induct
   646     Suc_Suc_eq                  ~> nat.inject
   647     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   648 
   649 
   650 *** HOL-Algebra ***
   651 
   652 * New locales for orders and lattices where the equivalence relation
   653 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   654 locales use a record structure with field eq for the equivalence.
   655 
   656 * New theory of factorial domains.
   657 
   658 * Units_l_inv and Units_r_inv are now simp rules by default.
   659 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   660 and/or r_inv will now also require deletion of these lemmas.
   661 
   662 * Renamed the following theorems, INCOMPATIBILITY:
   663 
   664 UpperD ~> Upper_memD
   665 LowerD ~> Lower_memD
   666 least_carrier ~> least_closed
   667 greatest_carrier ~> greatest_closed
   668 greatest_Lower_above ~> greatest_Lower_below
   669 one_zero ~> carrier_one_zero
   670 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   671 
   672 
   673 *** HOL-Nominal ***
   674 
   675 * Nominal datatypes can now contain type-variables.
   676 
   677 * Commands 'nominal_inductive' and 'equivariance' work with local
   678 theory targets.
   679 
   680 * Nominal primrec can now works with local theory targets and its
   681 specification syntax now conforms to the general format as seen in
   682 'inductive' etc.
   683 
   684 * Method "perm_simp" honours the standard simplifier attributes
   685 (no_asm), (no_asm_use) etc.
   686 
   687 * The new predicate #* is defined like freshness, except that on the
   688 left hand side can be a set or list of atoms.
   689 
   690 * Experimental command 'nominal_inductive2' derives strong induction
   691 principles for inductive definitions.  In contrast to
   692 'nominal_inductive', which can only deal with a fixed number of
   693 binders, it can deal with arbitrary expressions standing for sets of
   694 atoms to be avoided.  The only inductive definition we have at the
   695 moment that needs this generalisation is the typing rule for Lets in
   696 the algorithm W:
   697 
   698  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   699  -----------------------------------------------------------------
   700          Gamma |- Let x be t1 in t2 : T2
   701 
   702 In this rule one wants to avoid all the binders that are introduced by
   703 "close Gamma T1".  We are looking for other examples where this
   704 feature might be useful.  Please let us know.
   705 
   706 
   707 *** HOLCF ***
   708 
   709 * Reimplemented the simplification procedure for proving continuity
   710 subgoals.  The new simproc is extensible; users can declare additional
   711 continuity introduction rules with the attribute [cont2cont].
   712 
   713 * The continuity simproc now uses a different introduction rule for
   714 solving continuity subgoals on terms with lambda abstractions.  In
   715 some rare cases the new simproc may fail to solve subgoals that the
   716 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   717 Potential INCOMPATIBILITY.
   718 
   719 * Command 'fixrec': specification syntax now conforms to the general
   720 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   721 examples.  INCOMPATIBILITY.
   722 
   723 
   724 *** ZF ***
   725 
   726 * Proof of Zorn's Lemma for partial orders.
   727 
   728 
   729 *** ML ***
   730 
   731 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   732 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   733 depends on multithreading, so timouts will not work before Poly/ML
   734 5.2.1!
   735 
   736 * High-level support for concurrent ML programming, see
   737 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   738 particularly convenient to organize independent functional
   739 computations.  The concept of "synchronized variables" provides a
   740 higher-order interface for components with shared state, avoiding the
   741 delicate details of mutexes and condition variables.  (Requires
   742 Poly/ML 5.2.1 or later.)
   743 
   744 * ML bindings produced via Isar commands are stored within the Isar
   745 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   746 become thread-safe and work with undo as expected (concerning
   747 top-level bindings, not side-effects on global references).
   748 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   749 compiler at runtime; really global bindings need to be given outside a
   750 theory.  (Requires Poly/ML 5.2 or later.)
   751 
   752 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   753 context.  Top-level ML bindings are stored within the proof context in
   754 a purely sequential fashion, disregarding the nested proof structure.
   755 ML bindings introduced by 'ML_prf' are discarded at the end of the
   756 proof.  (Requires Poly/ML 5.2 or later.)
   757 
   758 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   759 and Method.setup, as well as Isar commands 'attribute_setup' and
   760 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   761 existing code accordingly, or use plain 'setup' together with old
   762 Method.add_method.
   763 
   764 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   765 to 'a -> thm, while results are always tagged with an authentic oracle
   766 name.  The Isar command 'oracle' is now polymorphic, no argument type
   767 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   768 accordingly.  Note that extra performance may be gained by producing
   769 the cterm carefully, avoiding slow Thm.cterm_of.
   770 
   771 * Simplified interface for defining document antiquotations via
   772 ThyOutput.antiquotation, ThyOutput.output, and optionally
   773 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   774 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   775 examples.
   776 
   777 * More systematic treatment of long names, abstract name bindings, and
   778 name space operations.  Basic operations on qualified names have been
   779 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   780 Long_Name.append.  Old type bstring has been mostly replaced by
   781 abstract type binding (see structure Binding), which supports precise
   782 qualification by packages and local theory targets, as well as proper
   783 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   784 bstring values into Binding.name, or better pass through abstract
   785 bindings everywhere.  See further src/Pure/General/long_name.ML,
   786 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   787 
   788 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   789 LocalTheory.note etc.) now refer to the *full* internal name, not the
   790 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   791 
   792 * Disposed old type and term read functions (Sign.read_def_typ,
   793 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   794 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   795 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   796 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   797 resort for legacy applications.
   798 
   799 * Disposed old declarations, tactics, tactic combinators that refer to
   800 the simpset or claset of an implicit theory (such as Addsimps,
   801 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   802 embedded ML text, or local_simpset_of with a proper context passed as
   803 explicit runtime argument.
   804 
   805 * Rules and tactics that read instantiations (read_instantiate,
   806 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   807 context, which is required for parsing and type-checking.  Moreover,
   808 the variables are specified as plain indexnames, not string encodings
   809 thereof.  INCOMPATIBILITY.
   810 
   811 * Generic Toplevel.add_hook interface allows to analyze the result of
   812 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   813 for theorem dependency output of transactions resulting in a new
   814 theory state.
   815 
   816 * ML antiquotations: block-structured compilation context indicated by
   817 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   818 
   819   @{binding name}                         - basic name binding
   820   @{let ?pat = term}                      - term abbreviation (HO matching)
   821   @{note name = fact}                     - fact abbreviation
   822   @{thm fact}                             - singleton fact (with attributes)
   823   @{thms fact}                            - general fact (with attributes)
   824   @{lemma prop by method}                 - singleton goal
   825   @{lemma prop by meth1 meth2}            - singleton goal
   826   @{lemma prop1 ... propN by method}      - general goal
   827   @{lemma prop1 ... propN by meth1 meth2} - general goal
   828   @{lemma (open) ...}                     - open derivation
   829 
   830 
   831 *** System ***
   832 
   833 * The Isabelle "emacs" tool provides a specific interface to invoke
   834 Proof General / Emacs, with more explicit failure if that is not
   835 installed (the old isabelle-interface script silently falls back on
   836 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   837 installation location of the Proof General distribution.
   838 
   839 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   840 the Isabelle process into a JVM/Scala application.  See
   841 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   842 process wrapper has been discontinued.)
   843 
   844 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   845 
   846 * Various status messages (with exact source position information) are
   847 emitted, if proper markup print mode is enabled.  This allows
   848 user-interface components to provide detailed feedback on internal
   849 prover operations.
   850 
   851 
   852 
   853 New in Isabelle2008 (June 2008)
   854 -------------------------------
   855 
   856 *** General ***
   857 
   858 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   859 and updated, with formally checked references as hyperlinks.
   860 
   861 * Theory loader: use_thy (and similar operations) no longer set the
   862 implicit ML context, which was occasionally hard to predict and in
   863 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   864 provides a proper context already.
   865 
   866 * Theory loader: old-style ML proof scripts being *attached* to a thy
   867 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   868 'use' within a theory file will do the job.
   869 
   870 * Name space merge now observes canonical order, i.e. the second space
   871 is inserted into the first one, while existing entries in the first
   872 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   873 swap theory imports.
   874 
   875 * Syntax: symbol \<chi> is now considered a letter.  Potential
   876 INCOMPATIBILITY in identifier syntax etc.
   877 
   878 * Outer syntax: string tokens no longer admit escaped white space,
   879 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   880 white space without escapes.
   881 
   882 * Outer syntax: string tokens may contain arbitrary character codes
   883 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   884 "foo_bar".
   885 
   886 
   887 *** Pure ***
   888 
   889 * Context-dependent token translations.  Default setup reverts locally
   890 fixed variables, and adds hilite markup for undeclared frees.
   891 
   892 * Unused theorems can be found using the new command 'unused_thms'.
   893 There are three ways of invoking it:
   894 
   895 (1) unused_thms
   896      Only finds unused theorems in the current theory.
   897 
   898 (2) unused_thms thy_1 ... thy_n -
   899      Finds unused theorems in the current theory and all of its ancestors,
   900      excluding the theories thy_1 ... thy_n and all of their ancestors.
   901 
   902 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   903      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   904      their ancestors, excluding the theories thy_1 ... thy_n and all of
   905      their ancestors.
   906 
   907 In order to increase the readability of the list produced by
   908 unused_thms, theorems that have been created by a particular instance
   909 of a theory command such as 'inductive' or 'function' are considered
   910 to belong to the same "group", meaning that if at least one theorem in
   911 this group is used, the other theorems in the same group are no longer
   912 reported as unused.  Moreover, if all theorems in the group are
   913 unused, only one theorem in the group is displayed.
   914 
   915 Note that proof objects have to be switched on in order for
   916 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   917 usually the case when using Proof General with the default settings).
   918 
   919 * Authentic naming of facts disallows ad-hoc overwriting of previous
   920 theorems within the same name space.  INCOMPATIBILITY, need to remove
   921 duplicate fact bindings, or even accidental fact duplications.  Note
   922 that tools may maintain dynamically scoped facts systematically, using
   923 PureThy.add_thms_dynamic.
   924 
   925 * Command 'hide' now allows to hide from "fact" name space as well.
   926 
   927 * Eliminated destructive theorem database, simpset, claset, and
   928 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   929 update of theories within ML code.
   930 
   931 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   932 INCOMPATIBILITY, object-logics depending on former Pure require
   933 additional setup PureThy.old_appl_syntax_setup; object-logics
   934 depending on former CPure need to refer to Pure.
   935 
   936 * Commands 'use' and 'ML' are now purely functional, operating on
   937 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   938 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   939 INCOMPATIBILITY.
   940 
   941 * Command 'setup': discontinued implicit version with ML reference.
   942 
   943 * Instantiation target allows for simultaneous specification of class
   944 instance operations together with an instantiation proof.
   945 Type-checking phase allows to refer to class operations uniformly.
   946 See src/HOL/Complex/Complex.thy for an Isar example and
   947 src/HOL/Library/Eval.thy for an ML example.
   948 
   949 * Indexing of literal facts: be more serious about including only
   950 facts from the visible specification/proof context, but not the
   951 background context (locale etc.).  Affects `prop` notation and method
   952 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   953 situations.
   954 
   955 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   956 "(open)" option, which used to expose internal bound variables to the
   957 proof text.
   958 
   959 * Isar statements: removed obsolete case "rule_context".
   960 INCOMPATIBILITY, better use explicit fixes/assumes.
   961 
   962 * Locale proofs: default proof step now includes 'unfold_locales';
   963 hence 'proof' without argument may be used to unfold locale
   964 predicates.
   965 
   966 
   967 *** Document preparation ***
   968 
   969 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   970 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   971 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   972 spot); renamed link color from "darkblue" to "linkcolor" (default
   973 value unchanged, can be redefined via \definecolor); no longer sets
   974 "a4paper" option (unnecessary or even intrusive).
   975 
   976 * Antiquotation @{lemma A method} proves proposition A by the given
   977 method (either a method name or a method name plus (optional) method
   978 arguments in parentheses) and prints A just like @{prop A}.
   979 
   980 
   981 *** HOL ***
   982 
   983 * New primrec package.  Specification syntax conforms in style to
   984 definition/function/....  No separate induction rule is provided.  The
   985 "primrec" command distinguishes old-style and new-style specifications
   986 by syntax.  The former primrec package is now named OldPrimrecPackage.
   987 When adjusting theories, beware: constants stemming from new-style
   988 primrec specifications have authentic syntax.
   989 
   990 * Metis prover is now an order of magnitude faster, and also works
   991 with multithreading.
   992 
   993 * Metis: the maximum number of clauses that can be produced from a
   994 theorem is now given by the attribute max_clauses.  Theorems that
   995 exceed this number are ignored, with a warning printed.
   996 
   997 * Sledgehammer no longer produces structured proofs by default. To
   998 enable, declare [[sledgehammer_full = true]].  Attributes
   999 reconstruction_modulus, reconstruction_sorts renamed
  1000 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
  1001 
  1002 * Method "induct_scheme" derives user-specified induction rules
  1003 from well-founded induction and completeness of patterns. This factors
  1004 out some operations that are done internally by the function package
  1005 and makes them available separately.  See
  1006 src/HOL/ex/Induction_Scheme.thy for examples.
  1007 
  1008 * More flexible generation of measure functions for termination
  1009 proofs: Measure functions can be declared by proving a rule of the
  1010 form "is_measure f" and giving it the [measure_function] attribute.
  1011 The "is_measure" predicate is logically meaningless (always true), and
  1012 just guides the heuristic.  To find suitable measure functions, the
  1013 termination prover sets up the goal "is_measure ?f" of the appropriate
  1014 type and generates all solutions by prolog-style backwards proof using
  1015 the declared rules.
  1016 
  1017 This setup also deals with rules like 
  1018 
  1019   "is_measure f ==> is_measure (list_size f)"
  1020 
  1021 which accommodates nested datatypes that recurse through lists.
  1022 Similar rules are predeclared for products and option types.
  1023 
  1024 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
  1025 
  1026   INCOMPATIBILITIES:
  1027 
  1028   - Definitions of overloaded constants on sets have to be replaced by
  1029     definitions on => and bool.
  1030 
  1031   - Some definitions of overloaded operators on sets can now be proved
  1032     using the definitions of the operators on => and bool.  Therefore,
  1033     the following theorems have been renamed:
  1034 
  1035       subset_def   -> subset_eq
  1036       psubset_def  -> psubset_eq
  1037       set_diff_def -> set_diff_eq
  1038       Compl_def    -> Compl_eq
  1039       Sup_set_def  -> Sup_set_eq
  1040       Inf_set_def  -> Inf_set_eq
  1041       sup_set_def  -> sup_set_eq
  1042       inf_set_def  -> inf_set_eq
  1043 
  1044   - Due to the incompleteness of the HO unification algorithm, some
  1045     rules such as subst may require manual instantiation, if some of
  1046     the unknowns in the rule is a set.
  1047 
  1048   - Higher order unification and forward proofs:
  1049     The proof pattern
  1050 
  1051       have "P (S::'a set)" <...>
  1052       then have "EX S. P S" ..
  1053 
  1054     no longer works (due to the incompleteness of the HO unification
  1055     algorithm) and must be replaced by the pattern
  1056 
  1057       have "EX S. P S"
  1058       proof
  1059         show "P S" <...>
  1060       qed
  1061 
  1062   - Calculational reasoning with subst (or similar rules):
  1063     The proof pattern
  1064 
  1065       have "P (S::'a set)" <...>
  1066       also have "S = T" <...>
  1067       finally have "P T" .
  1068 
  1069     no longer works (for similar reasons as the previous example) and
  1070     must be replaced by something like
  1071 
  1072       have "P (S::'a set)" <...>
  1073       moreover have "S = T" <...>
  1074       ultimately have "P T" by simp
  1075 
  1076   - Tactics or packages written in ML code:
  1077     Code performing pattern matching on types via
  1078 
  1079       Type ("set", [T]) => ...
  1080 
  1081     must be rewritten. Moreover, functions like strip_type or
  1082     binder_types no longer return the right value when applied to a
  1083     type of the form
  1084 
  1085       T1 => ... => Tn => U => bool
  1086 
  1087     rather than
  1088 
  1089       T1 => ... => Tn => U set
  1090 
  1091 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1092 Wellfounded_Relations to theory Wellfounded.
  1093 
  1094 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1095 
  1096 * Class finite no longer treats UNIV as class parameter.  Use class
  1097 enum from theory Library/Enum instead to achieve a similar effect.
  1098 INCOMPATIBILITY.
  1099 
  1100 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1101 and "Cons".  INCOMPATIBILITY.
  1102 
  1103 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1104 Potential INCOMPATIBILITY.
  1105 
  1106 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1107 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1108 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1109 
  1110 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1111 the same name in theory Orderings:
  1112 
  1113   less_trans
  1114   less_linear
  1115   le_imp_less_or_eq
  1116   le_less_trans
  1117   less_le_trans
  1118   less_not_sym
  1119   less_asym
  1120 
  1121 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1122 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1123 and different variable names.
  1124 
  1125 * Library/Option_ord.thy: Canonical order on option type.
  1126 
  1127 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1128 finite maps.
  1129 
  1130 * Library/Countable.thy: Type class for countable types.
  1131 
  1132 * Theory Int: The representation of numerals has changed.  The infix
  1133 operator BIT and the bit datatype with constructors B0 and B1 have
  1134 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1135 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1136 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1137 accordingly.
  1138 
  1139 * Theory Nat: definition of <= and < on natural numbers no longer
  1140 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1141 le_def and less_def have disappeared.  Consider lemmas not_less
  1142 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1143 
  1144 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1145 (whose purpose mainly is for various fold_set functionals) have been
  1146 abandoned in favor of the existing algebraic classes
  1147 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1148 lower_semilattice (resp. upper_semilattice) and linorder.
  1149 INCOMPATIBILITY.
  1150 
  1151 * Theory Transitive_Closure: induct and cases rules now declare proper
  1152 case_names ("base" and "step").  INCOMPATIBILITY.
  1153 
  1154 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1155 lattices.  The form set-specific version is available as
  1156 Inductive.lfp_ordinal_induct_set.
  1157 
  1158 * Renamed theorems "power.simps" to "power_int.simps".
  1159 INCOMPATIBILITY.
  1160 
  1161 * Class semiring_div provides basic abstract properties of semirings
  1162 with division and modulo operations.  Subsumes former class dvd_mod.
  1163 
  1164 * Merged theories IntDef, Numeral and IntArith into unified theory
  1165 Int.  INCOMPATIBILITY.
  1166 
  1167 * Theory Library/Code_Index: type "index" now represents natural
  1168 numbers rather than integers.  INCOMPATIBILITY.
  1169 
  1170 * New class "uminus" with operation "uminus" (split of from class
  1171 "minus" which now only has operation "minus", binary).
  1172 INCOMPATIBILITY.
  1173 
  1174 * Constants "card", "internal_split", "option_map" now with authentic
  1175 syntax.  INCOMPATIBILITY.
  1176 
  1177 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1178 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1179 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1180 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1181 Sup_set_def, le_def, less_def, option_map_def now with object
  1182 equality.  INCOMPATIBILITY.
  1183 
  1184 * Records. Removed K_record, and replaced it by pure lambda term
  1185 %x. c. The simplifier setup is now more robust against eta expansion.
  1186 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1187 
  1188 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1189 
  1190 * Library/ListVector: new theory of arithmetic vector operations.
  1191 
  1192 * Library/Order_Relation: new theory of various orderings as sets of
  1193 pairs.  Defines preorders, partial orders, linear orders and
  1194 well-orders on sets and on types.
  1195 
  1196 
  1197 *** ZF ***
  1198 
  1199 * Renamed some theories to allow to loading both ZF and HOL in the
  1200 same session:
  1201 
  1202   Datatype  -> Datatype_ZF
  1203   Inductive -> Inductive_ZF
  1204   Int       -> Int_ZF
  1205   IntDiv    -> IntDiv_ZF
  1206   Nat       -> Nat_ZF
  1207   List      -> List_ZF
  1208   Main      -> Main_ZF
  1209 
  1210 INCOMPATIBILITY: ZF theories that import individual theories below
  1211 Main might need to be adapted.  Regular theory Main is still
  1212 available, as trivial extension of Main_ZF.
  1213 
  1214 
  1215 *** ML ***
  1216 
  1217 * ML within Isar: antiquotation @{const name} or @{const
  1218 name(typargs)} produces statically-checked Const term.
  1219 
  1220 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1221 (of the same name).  Removed obsolete print command.
  1222 
  1223 * Removed obsolete "use_legacy_bindings" function.
  1224 
  1225 * The ``print mode'' is now a thread-local value derived from a global
  1226 template (the former print_mode reference), thus access becomes
  1227 non-critical.  The global print_mode reference is for session
  1228 management only; user-code should use print_mode_value,
  1229 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1230 
  1231 * Functions system/system_out provide a robust way to invoke external
  1232 shell commands, with propagation of interrupts (requires Poly/ML
  1233 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1234 
  1235 
  1236 *** System ***
  1237 
  1238 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1239 in accordance with Proof General 3.7, which prefers GNU emacs.
  1240 
  1241 * isatool tty runs Isabelle process with plain tty interaction;
  1242 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1243 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1244 
  1245 * isatool browser now works with Cygwin as well, using general
  1246 "javapath" function defined in Isabelle process environment.
  1247 
  1248 * YXML notation provides a simple and efficient alternative to
  1249 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1250 isatool yxml as described in the Isabelle system manual.
  1251 
  1252 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1253 provides general wrapper for managing an Isabelle process in a robust
  1254 fashion, with ``cooked'' output from stdin/stderr.
  1255 
  1256 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1257 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1258 
  1259 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1260 way of changing the user's settings is via
  1261 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1262 script.
  1263 
  1264 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1265 cores of the underlying machine, which is a good starting point for
  1266 optimal performance tuning.  The corresponding usedir option -M allows
  1267 "max" as an alias for "0".  WARNING: does not work on certain versions
  1268 of Mac OS (with Poly/ML 5.1).
  1269 
  1270 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1271 adverse effect of Isabelle flooding interactive front-ends (notably
  1272 ProofGeneral / XEmacs).
  1273 
  1274 
  1275 
  1276 New in Isabelle2007 (November 2007)
  1277 -----------------------------------
  1278 
  1279 *** General ***
  1280 
  1281 * More uniform information about legacy features, notably a
  1282 warning/error of "Legacy feature: ...", depending on the state of the
  1283 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1284 legacy features will disappear eventually.
  1285 
  1286 * Theory syntax: the header format ``theory A = B + C:'' has been
  1287 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1288 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1289 
  1290 * Theory syntax: the old non-Isar theory file format has been
  1291 discontinued altogether.  Note that ML proof scripts may still be used
  1292 with Isar theories; migration is usually quite simple with the ML
  1293 function use_legacy_bindings.  INCOMPATIBILITY.
  1294 
  1295 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1296 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1297 quotes.
  1298 
  1299 * Theory loader: be more serious about observing the static theory
  1300 header specifications (including optional directories), but not the
  1301 accidental file locations of previously successful loads.  The strict
  1302 update policy of former update_thy is now already performed by
  1303 use_thy, so the former has been removed; use_thys updates several
  1304 theories simultaneously, just as 'imports' within a theory header
  1305 specification, but without merging the results.  Potential
  1306 INCOMPATIBILITY: may need to refine theory headers and commands
  1307 ROOT.ML which depend on load order.
  1308 
  1309 * Theory loader: optional support for content-based file
  1310 identification, instead of the traditional scheme of full physical
  1311 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1312 (cf. the system manual).  The new scheme allows to work with
  1313 non-finished theories in persistent session images, such that source
  1314 files may be moved later on without requiring reloads.
  1315 
  1316 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1317 file (with the same base name as the theory) are considered a legacy
  1318 feature, which will disappear eventually. Even now, the theory loader
  1319 no longer maintains dependencies on such files.
  1320 
  1321 * Syntax: the scope for resolving ambiguities via type-inference is
  1322 now limited to individual terms, instead of whole simultaneous
  1323 specifications as before. This greatly reduces the complexity of the
  1324 syntax module and improves flexibility by separating parsing and
  1325 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1326 'fixes' etc.) are required in rare situations.
  1327 
  1328 * Syntax: constants introduced by new-style packages ('definition',
  1329 'abbreviation' etc.) are passed through the syntax module in
  1330 ``authentic mode''. This means that associated mixfix annotations
  1331 really stick to such constants, independently of potential name space
  1332 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1333 trees are represented slightly differently, may need to adapt syntax
  1334 translations accordingly. Use CONST marker in 'translations' and
  1335 @{const_syntax} antiquotation in 'parse_translation' etc.
  1336 
  1337 * Legacy goal package: reduced interface to the bare minimum required
  1338 to keep existing proof scripts running.  Most other user-level
  1339 functions are now part of the OldGoals structure, which is *not* open
  1340 by default (consider isatool expandshort before open OldGoals).
  1341 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1342 these tend to cause confusion about the actual goal (!) context being
  1343 used here, which is not necessarily the same as the_context().
  1344 
  1345 * Command 'find_theorems': supports "*" wild-card in "name:"
  1346 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1347 support a specific search form (see ProofGeneral/CHANGES).
  1348 
  1349 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1350 by default, which means that "prems" (and also "fixed variables") are
  1351 suppressed from proof state output.  Note that the ProofGeneral
  1352 settings mechanism allows to change and save options persistently, but
  1353 older versions of Isabelle will fail to start up if a negative prems
  1354 limit is imposed.
  1355 
  1356 * Local theory targets may be specified by non-nested blocks of
  1357 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1358 contain definitions, theorems etc., including any derived mechanism
  1359 that has been implemented on top of these primitives.  This concept
  1360 generalizes the existing ``theorem (in ...)'' towards more versatility
  1361 and scalability.
  1362 
  1363 * Proof General interface: proper undo of final 'end' command;
  1364 discontinued Isabelle/classic mode (ML proof scripts).
  1365 
  1366 
  1367 *** Document preparation ***
  1368 
  1369 * Added antiquotation @{theory name} which prints the given name,
  1370 after checking that it refers to a valid ancestor theory in the
  1371 current context.
  1372 
  1373 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1374 check the given source text as ML type/structure, printing verbatim.
  1375 
  1376 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1377 "c args == rhs" given in the current context.  (Any number of
  1378 arguments may be given on the LHS.)
  1379 
  1380 
  1381 *** Pure ***
  1382 
  1383 * The 'class' package offers a combination of axclass and locale to
  1384 achieve Haskell-like type classes in Isabelle.  Definitions and
  1385 theorems within a class context produce both relative results (with
  1386 implicit parameters according to the locale context), and polymorphic
  1387 constants with qualified polymorphism (according to the class
  1388 context).  Within the body context of a 'class' target, a separate
  1389 syntax layer ("user space type system") takes care of converting
  1390 between global polymorphic consts and internal locale representation.
  1391 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1392 "isatool doc classes" provides a tutorial.
  1393 
  1394 * Generic code generator framework allows to generate executable
  1395 code for ML and Haskell (including Isabelle classes).  A short usage
  1396 sketch:
  1397 
  1398     internal compilation:
  1399         export_code <list of constants (term syntax)> in SML
  1400     writing SML code to a file:
  1401         export_code <list of constants (term syntax)> in SML <filename>
  1402     writing OCaml code to a file:
  1403         export_code <list of constants (term syntax)> in OCaml <filename>
  1404     writing Haskell code to a bunch of files:
  1405         export_code <list of constants (term syntax)> in Haskell <filename>
  1406 
  1407     evaluating closed propositions to True/False using code generation:
  1408         method ``eval''
  1409 
  1410 Reasonable default setup of framework in HOL.
  1411 
  1412 Theorem attributs for selecting and transforming function equations theorems:
  1413 
  1414     [code fun]:        select a theorem as function equation for a specific constant
  1415     [code fun del]:    deselect a theorem as function equation for a specific constant
  1416     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1417     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1418 
  1419 User-defined serializations (target in {SML, OCaml, Haskell}):
  1420 
  1421     code_const <and-list of constants (term syntax)>
  1422       {(target) <and-list of const target syntax>}+
  1423 
  1424     code_type <and-list of type constructors>
  1425       {(target) <and-list of type target syntax>}+
  1426 
  1427     code_instance <and-list of instances>
  1428       {(target)}+
  1429         where instance ::= <type constructor> :: <class>
  1430 
  1431     code_class <and_list of classes>
  1432       {(target) <and-list of class target syntax>}+
  1433         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1434 
  1435 code_instance and code_class only are effective to target Haskell.
  1436 
  1437 For example usage see src/HOL/ex/Codegenerator.thy and
  1438 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1439 generation from Isabelle/HOL theories is available via "isatool doc
  1440 codegen".
  1441 
  1442 * Code generator: consts in 'consts_code' Isar commands are now
  1443 referred to by usual term syntax (including optional type
  1444 annotations).
  1445 
  1446 * Command 'no_translations' removes translation rules from theory
  1447 syntax.
  1448 
  1449 * Overloaded definitions are now actually checked for acyclic
  1450 dependencies.  The overloading scheme is slightly more general than
  1451 that of Haskell98, although Isabelle does not demand an exact
  1452 correspondence to type class and instance declarations.
  1453 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1454 exotic versions of overloading -- at the discretion of the user!
  1455 
  1456 Polymorphic constants are represented via type arguments, i.e. the
  1457 instantiation that matches an instance against the most general
  1458 declaration given in the signature.  For example, with the declaration
  1459 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1460 as c(nat).  Overloading is essentially simultaneous structural
  1461 recursion over such type arguments.  Incomplete specification patterns
  1462 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1463 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1464 Command 'print_theory' outputs the normalized system of recursive
  1465 equations, see section "definitions".
  1466 
  1467 * Configuration options are maintained within the theory or proof
  1468 context (with name and type bool/int/string), providing a very simple
  1469 interface to a poor-man's version of general context data.  Tools may
  1470 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1471 these values using Config.get etc.  Users may change options via an
  1472 associated attribute of the same name.  This form of context
  1473 declaration works particularly well with commands 'declare' or
  1474 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1475 very easy to avoid global references, which would not observe Isar
  1476 toplevel undo/redo and fail to work with multithreading.
  1477 
  1478 Various global ML references of Pure and HOL have been turned into
  1479 configuration options:
  1480 
  1481   Unify.search_bound		unify_search_bound
  1482   Unify.trace_bound		unify_trace_bound
  1483   Unify.trace_simp		unify_trace_simp
  1484   Unify.trace_types		unify_trace_types
  1485   Simplifier.simp_depth_limit	simp_depth_limit
  1486   Blast.depth_limit		blast_depth_limit
  1487   DatatypeProp.dtK		datatype_distinctness_limit
  1488   fast_arith_neq_limit  	fast_arith_neq_limit
  1489   fast_arith_split_limit	fast_arith_split_limit
  1490 
  1491 * Named collections of theorems may be easily installed as context
  1492 data using the functor NamedThmsFun (see also
  1493 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1494 attributes; there is also a toplevel print command.  This facility is
  1495 just a common case of general context data, which is the preferred way
  1496 for anything more complex than just a list of facts in canonical
  1497 order.
  1498 
  1499 * Isar: command 'declaration' augments a local theory by generic
  1500 declaration functions written in ML.  This enables arbitrary content
  1501 being added to the context, depending on a morphism that tells the
  1502 difference of the original declaration context wrt. the application
  1503 context encountered later on.
  1504 
  1505 * Isar: proper interfaces for simplification procedures.  Command
  1506 'simproc_setup' declares named simprocs (with match patterns, and body
  1507 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1508 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1509 
  1510 * Isar: an extra pair of brackets around attribute declarations
  1511 abbreviates a theorem reference involving an internal dummy fact,
  1512 which will be ignored later --- only the effect of the attribute on
  1513 the background context will persist.  This form of in-place
  1514 declarations is particularly useful with commands like 'declare' and
  1515 'using', for example ``have A using [[simproc a]] by simp''.
  1516 
  1517 * Isar: method "assumption" (and implicit closing of subproofs) now
  1518 takes simple non-atomic goal assumptions into account: after applying
  1519 an assumption as a rule the resulting subgoals are solved by atomic
  1520 assumption steps.  This is particularly useful to finish 'obtain'
  1521 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1522 without referring to the original premise "!!x. P x ==> thesis" in the
  1523 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1524 more permissive.
  1525 
  1526 * Isar: implicit use of prems from the Isar proof context is
  1527 considered a legacy feature.  Common applications like ``have A .''
  1528 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1529 referencing facts explicitly here improves readability and
  1530 maintainability of proof texts.
  1531 
  1532 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1533 the obtained context from the course of reasoning!  For example:
  1534 
  1535   assume "EX x y. A x & B y"   -- "any previous fact"
  1536   then guess x and y by clarify
  1537 
  1538 This technique is potentially adventurous, depending on the facts and
  1539 proof tools being involved here.
  1540 
  1541 * Isar: known facts from the proof context may be specified as literal
  1542 propositions, using ASCII back-quote syntax.  This works wherever
  1543 named facts used to be allowed so far, in proof commands, proof
  1544 methods, attributes etc.  Literal facts are retrieved from the context
  1545 according to unification of type and term parameters.  For example,
  1546 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1547 theorems in the current context, then these are valid literal facts:
  1548 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1549 
  1550 There is also a proof method "fact" which does the same composition
  1551 for explicit goal states, e.g. the following proof texts coincide with
  1552 certain special cases of literal facts:
  1553 
  1554   have "A" by fact                 ==  note `A`
  1555   have "A ==> B" by fact           ==  note `A ==> B`
  1556   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1557   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1558 
  1559 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1560 outer syntax.  Thus symbolic identifiers may be used without
  1561 additional white space in declarations like this: ``assume *: A''.
  1562 
  1563 * Isar: 'print_facts' prints all local facts of the current context,
  1564 both named and unnamed ones.
  1565 
  1566 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1567 
  1568   def x == "t" and y == "u"
  1569 
  1570 * Isar: added command 'unfolding', which is structurally similar to
  1571 'using', but affects both the goal state and facts by unfolding given
  1572 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1573 'unfolded' attribute may be replaced by first-class proof text.
  1574 
  1575 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1576 and command 'unfolding' now all support object-level equalities
  1577 (potentially conditional).  The underlying notion of rewrite rule is
  1578 analogous to the 'rule_format' attribute, but *not* that of the
  1579 Simplifier (which is usually more generous).
  1580 
  1581 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1582 premises of a theorem by n. Useful in conjunction with drule.
  1583 
  1584 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1585 method expression within a sandbox consisting of the first N
  1586 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1587 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1588 simplifies all new goals that emerge from applying rule foo to the
  1589 originally first one.
  1590 
  1591 * Isar: schematic goals are no longer restricted to higher-order
  1592 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1593 expected.
  1594 
  1595 * Isar: the conclusion of a long theorem statement is now either
  1596 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1597 (essentially a disjunction of cases with local parameters and
  1598 assumptions).  The latter allows to express general elimination rules
  1599 adequately; in this notation common elimination rules look like this:
  1600 
  1601   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1602     assumes "EX x. P x"
  1603     obtains x where "P x"
  1604 
  1605   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1606     assumes "A & B"
  1607     obtains A and B
  1608 
  1609   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1610     assumes "A | B"
  1611     obtains
  1612       A
  1613     | B
  1614 
  1615 The subsequent classical rules even refer to the formal "thesis"
  1616 explicitly:
  1617 
  1618   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1619     obtains "~ thesis"
  1620 
  1621   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1622     obtains "thesis ==> something"
  1623 
  1624 The actual proof of an 'obtains' statement is analogous to that of the
  1625 Isar proof element 'obtain', only that there may be several cases.
  1626 Optional case names may be specified in parentheses; these will be
  1627 available both in the present proof and as annotations in the
  1628 resulting rule, for later use with the 'cases' method (cf. attribute
  1629 case_names).
  1630 
  1631 * Isar: the assumptions of a long theorem statement are available as
  1632 "assms" fact in the proof context.  This is more appropriate than the
  1633 (historical) "prems", which refers to all assumptions of the current
  1634 context, including those from the target locale, proof body etc.
  1635 
  1636 * Isar: 'print_statement' prints theorems from the current theory or
  1637 proof context in long statement form, according to the syntax of a
  1638 top-level lemma.
  1639 
  1640 * Isar: 'obtain' takes an optional case name for the local context
  1641 introduction rule (default "that").
  1642 
  1643 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1644 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1645 to occur.
  1646 
  1647 * Pure: syntax "CONST name" produces a fully internalized constant
  1648 according to the current context.  This is particularly useful for
  1649 syntax translations that should refer to internal constant
  1650 representations independently of name spaces.
  1651 
  1652 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1653 instead of "FOO ". This allows multiple binder declarations to coexist
  1654 in the same context.  INCOMPATIBILITY.
  1655 
  1656 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1657 primitive that also works in a locale context (both for constants and
  1658 fixed variables). Type declaration and internal syntactic representation
  1659 of given constants retrieved from the context. Likewise, the
  1660 'no_notation' command allows to remove given syntax annotations from the
  1661 current context.
  1662 
  1663 * Isar/locales: new derived specification elements 'axiomatization',
  1664 'definition', 'abbreviation', which support type-inference, admit
  1665 object-level specifications (equality, equivalence).  See also the
  1666 isar-ref manual.  Examples:
  1667 
  1668   axiomatization
  1669     eq  (infix "===" 50) where
  1670     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1671 
  1672   definition "f x y = x + y + 1"
  1673   definition g where "g x = f x x"
  1674 
  1675   abbreviation
  1676     neq  (infix "=!=" 50) where
  1677     "x =!= y == ~ (x === y)"
  1678 
  1679 These specifications may be also used in a locale context.  Then the
  1680 constants being introduced depend on certain fixed parameters, and the
  1681 constant name is qualified by the locale base name.  An internal
  1682 abbreviation takes care for convenient input and output, making the
  1683 parameters implicit and using the original short name.  See also
  1684 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1685 entities from a monomorphic theory.
  1686 
  1687 Presently, abbreviations are only available 'in' a target locale, but
  1688 not inherited by general import expressions.  Also note that
  1689 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1690 'translations' in common applications.  The "no_abbrevs" print mode
  1691 prevents folding of abbreviations in term output.
  1692 
  1693 Concrete syntax is attached to specified constants in internal form,
  1694 independently of name spaces.  The parse tree representation is
  1695 slightly different -- use 'notation' instead of raw 'syntax', and
  1696 'translations' with explicit "CONST" markup to accommodate this.
  1697 
  1698 * Pure/Isar: unified syntax for new-style specification mechanisms
  1699 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1700 full type inference and dummy patterns ("_").  For example:
  1701 
  1702   definition "K x _ = x"
  1703 
  1704   inductive conj for A B
  1705   where "A ==> B ==> conj A B"
  1706 
  1707 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1708 the current context.  Print mode "no_abbrevs" prevents inversion of
  1709 abbreviations on output.
  1710 
  1711 * Isar/locales: improved parameter handling: use of locales "var" and
  1712 "struct" no longer necessary; - parameter renamings are no longer
  1713 required to be injective.  For example, this allows to define
  1714 endomorphisms as locale endom = homom mult mult h.
  1715 
  1716 * Isar/locales: changed the way locales with predicates are defined.
  1717 Instead of accumulating the specification, the imported expression is
  1718 now an interpretation.  INCOMPATIBILITY: different normal form of
  1719 locale expressions.  In particular, in interpretations of locales with
  1720 predicates, goals repesenting already interpreted fragments are not
  1721 removed automatically.  Use methods `intro_locales' and
  1722 `unfold_locales'; see below.
  1723 
  1724 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1725 provide backward reasoning on locales predicates.  The methods are
  1726 aware of interpretations and discharge corresponding goals.
  1727 `intro_locales' is less aggressive then `unfold_locales' and does not
  1728 unfold predicates to assumptions.
  1729 
  1730 * Isar/locales: the order in which locale fragments are accumulated
  1731 has changed.  This enables to override declarations from fragments due
  1732 to interpretations -- for example, unwanted simp rules.
  1733 
  1734 * Isar/locales: interpretation in theories and proof contexts has been
  1735 extended.  One may now specify (and prove) equations, which are
  1736 unfolded in interpreted theorems.  This is useful for replacing
  1737 defined concepts (constants depending on locale parameters) by
  1738 concepts already existing in the target context.  Example:
  1739 
  1740   interpretation partial_order ["op <= :: [int, int] => bool"]
  1741     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1742 
  1743 Typically, the constant `partial_order.less' is created by a
  1744 definition specification element in the context of locale
  1745 partial_order.
  1746 
  1747 * Method "induct": improved internal context management to support
  1748 local fixes and defines on-the-fly. Thus explicit meta-level
  1749 connectives !!  and ==> are rarely required anymore in inductive goals
  1750 (using object-logic connectives for this purpose has been long
  1751 obsolete anyway). Common proof patterns are explained in
  1752 src/HOL/Induct/Common_Patterns.thy, see also
  1753 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1754 examples.
  1755 
  1756 * Method "induct": improved handling of simultaneous goals. Instead of
  1757 introducing object-level conjunction, the statement is now split into
  1758 several conclusions, while the corresponding symbolic cases are nested
  1759 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1760 see src/HOL/Induct/Common_Patterns.thy, for example.
  1761 
  1762 * Method "induct": mutual induction rules are now specified as a list
  1763 of rule sharing the same induction cases. HOL packages usually provide
  1764 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1765 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1766 mutual induction rules differently, i.e. like this:
  1767 
  1768   (induct rule: foo_bar.inducts)
  1769   (induct set: foo bar)
  1770   (induct pred: foo bar)
  1771   (induct type: foo bar)
  1772 
  1773 The ML function ProjectRule.projections turns old-style rules into the
  1774 new format.
  1775 
  1776 * Method "coinduct": dual of induction, see
  1777 src/HOL/Library/Coinductive_List.thy for various examples.
  1778 
  1779 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1780 considered a legacy feature.
  1781 
  1782 * Attribute "symmetric" produces result with standardized schematic
  1783 variables (index 0).  Potential INCOMPATIBILITY.
  1784 
  1785 * Simplifier: by default the simplifier trace only shows top level
  1786 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1787 default. Thus there is less danger of being flooded by the trace. The
  1788 trace indicates where parts have been suppressed.
  1789   
  1790 * Provers/classical: removed obsolete classical version of elim_format
  1791 attribute; classical elim/dest rules are now treated uniformly when
  1792 manipulating the claset.
  1793 
  1794 * Provers/classical: stricter checks to ensure that supplied intro,
  1795 dest and elim rules are well-formed; dest and elim rules must have at
  1796 least one premise.
  1797 
  1798 * Provers/classical: attributes dest/elim/intro take an optional
  1799 weight argument for the rule (just as the Pure versions).  Weights are
  1800 ignored by automated tools, but determine the search order of single
  1801 rule steps.
  1802 
  1803 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1804 where the body does not mention the bound variable.  Note that dummy
  1805 patterns implicitly depend on their context of bounds, which makes
  1806 "{_. _}" match any set comprehension as expected.  Potential
  1807 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1808 constant "_idtdummy" in the binding position.
  1809 
  1810 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1811 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1812 for example "A -> B" => "Pi A (%_. B)".
  1813 
  1814 * Pure: 'class_deps' command visualizes the subclass relation, using
  1815 the graph browser tool.
  1816 
  1817 * Pure: 'print_theory' now suppresses certain internal declarations by
  1818 default; use '!' option for full details.
  1819 
  1820 
  1821 *** HOL ***
  1822 
  1823 * Method "metis" proves goals by applying the Metis general-purpose
  1824 resolution prover (see also http://gilith.com/software/metis/).
  1825 Examples are in the directory MetisExamples.  WARNING: the
  1826 Isabelle/HOL-Metis integration does not yet work properly with
  1827 multi-threading.
  1828   
  1829 * Command 'sledgehammer' invokes external automatic theorem provers as
  1830 background processes.  It generates calls to the "metis" method if
  1831 successful. These can be pasted into the proof.  Users do not have to
  1832 wait for the automatic provers to return.  WARNING: does not really
  1833 work with multi-threading.
  1834 
  1835 * New "auto_quickcheck" feature tests outermost goal statements for
  1836 potential counter-examples.  Controlled by ML references
  1837 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1838 5000 milliseconds).  Fails silently if statements is outside of
  1839 executable fragment, or any other codgenerator problem occurs.
  1840 
  1841 * New constant "undefined" with axiom "undefined x = undefined".
  1842 
  1843 * Added class "HOL.eq", allowing for code generation with polymorphic
  1844 equality.
  1845 
  1846 * Some renaming of class constants due to canonical name prefixing in
  1847 the new 'class' package:
  1848 
  1849     HOL.abs ~> HOL.abs_class.abs
  1850     HOL.divide ~> HOL.divide_class.divide
  1851     0 ~> HOL.zero_class.zero
  1852     1 ~> HOL.one_class.one
  1853     op + ~> HOL.plus_class.plus
  1854     op - ~> HOL.minus_class.minus
  1855     uminus ~> HOL.minus_class.uminus
  1856     op * ~> HOL.times_class.times
  1857     op < ~> HOL.ord_class.less
  1858     op <= > HOL.ord_class.less_eq
  1859     Nat.power ~> Power.power_class.power
  1860     Nat.size ~> Nat.size_class.size
  1861     Numeral.number_of ~> Numeral.number_class.number_of
  1862     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1863     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1864     Orderings.min ~> Orderings.ord_class.min
  1865     Orderings.max ~> Orderings.ord_class.max
  1866     Divides.op div ~> Divides.div_class.div
  1867     Divides.op mod ~> Divides.div_class.mod
  1868     Divides.op dvd ~> Divides.div_class.dvd
  1869 
  1870 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1871 
  1872 a) User-defined constants using any of the names "plus", "minus",
  1873 "times", "less" or "less_eq". The standard syntax translations for
  1874 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1875 names.
  1876 
  1877 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1878 INCOMPATIBILITY: use more specific names.
  1879 
  1880 c) Permutative equations (e.g. "a + b = b + a")
  1881 Since the change of names also changes the order of terms, permutative
  1882 rewrite rules may get applied in a different order. Experience shows
  1883 that this is rarely the case (only two adaptions in the whole Isabelle
  1884 distribution).  INCOMPATIBILITY: rewrite proofs
  1885 
  1886 d) ML code directly refering to constant names
  1887 This in general only affects hand-written proof tactics, simprocs and
  1888 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1889 Consider using @{const_name} antiquotation.
  1890 
  1891 * New class "default" with associated constant "default".
  1892 
  1893 * Function "sgn" is now overloaded and available on int, real, complex
  1894 (and other numeric types), using class "sgn".  Two possible defs of
  1895 sgn are given as equational assumptions in the classes sgn_if and
  1896 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1897 INCOMPATIBILITY.
  1898 
  1899 * Locale "partial_order" now unified with class "order" (cf. theory
  1900 Orderings), added parameter "less".  INCOMPATIBILITY.
  1901 
  1902 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1903 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1904 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1905 
  1906 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1907 changed order of proof goals in instance proofs.
  1908 
  1909 * The transitivity reasoner for partial and linear orders is set up
  1910 for classes "order" and "linorder".  Instances of the reasoner are available
  1911 in all contexts importing or interpreting the corresponding locales.
  1912 Method "order" invokes the reasoner separately; the reasoner
  1913 is also integrated with the Simplifier as a solver.  Diagnostic
  1914 command 'print_orders' shows the available instances of the reasoner
  1915 in the current context.
  1916 
  1917 * Localized monotonicity predicate in theory "Orderings"; integrated
  1918 lemmas max_of_mono and min_of_mono with this predicate.
  1919 INCOMPATIBILITY.
  1920 
  1921 * Formulation of theorem "dense" changed slightly due to integration
  1922 with new class dense_linear_order.
  1923 
  1924 * Uniform lattice theory development in HOL.
  1925 
  1926     constants "meet" and "join" now named "inf" and "sup"
  1927     constant "Meet" now named "Inf"
  1928 
  1929     classes "meet_semilorder" and "join_semilorder" now named
  1930       "lower_semilattice" and "upper_semilattice"
  1931     class "lorder" now named "lattice"
  1932     class "comp_lat" now named "complete_lattice"
  1933 
  1934     Instantiation of lattice classes allows explicit definitions
  1935     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1936 
  1937   INCOMPATIBILITY.  Theorem renames:
  1938 
  1939     meet_left_le            ~> inf_le1
  1940     meet_right_le           ~> inf_le2
  1941     join_left_le            ~> sup_ge1
  1942     join_right_le           ~> sup_ge2
  1943     meet_join_le            ~> inf_sup_ord
  1944     le_meetI                ~> le_infI
  1945     join_leI                ~> le_supI
  1946     le_meet                 ~> le_inf_iff
  1947     le_join                 ~> ge_sup_conv
  1948     meet_idempotent         ~> inf_idem
  1949     join_idempotent         ~> sup_idem
  1950     meet_comm               ~> inf_commute
  1951     join_comm               ~> sup_commute
  1952     meet_leI1               ~> le_infI1
  1953     meet_leI2               ~> le_infI2
  1954     le_joinI1               ~> le_supI1
  1955     le_joinI2               ~> le_supI2
  1956     meet_assoc              ~> inf_assoc
  1957     join_assoc              ~> sup_assoc
  1958     meet_left_comm          ~> inf_left_commute
  1959     meet_left_idempotent    ~> inf_left_idem
  1960     join_left_comm          ~> sup_left_commute
  1961     join_left_idempotent    ~> sup_left_idem
  1962     meet_aci                ~> inf_aci
  1963     join_aci                ~> sup_aci
  1964     le_def_meet             ~> le_iff_inf
  1965     le_def_join             ~> le_iff_sup
  1966     join_absorp2            ~> sup_absorb2
  1967     join_absorp1            ~> sup_absorb1
  1968     meet_absorp1            ~> inf_absorb1
  1969     meet_absorp2            ~> inf_absorb2
  1970     meet_join_absorp        ~> inf_sup_absorb
  1971     join_meet_absorp        ~> sup_inf_absorb
  1972     distrib_join_le         ~> distrib_sup_le
  1973     distrib_meet_le         ~> distrib_inf_le
  1974 
  1975     add_meet_distrib_left   ~> add_inf_distrib_left
  1976     add_join_distrib_left   ~> add_sup_distrib_left
  1977     is_join_neg_meet        ~> is_join_neg_inf
  1978     is_meet_neg_join        ~> is_meet_neg_sup
  1979     add_meet_distrib_right  ~> add_inf_distrib_right
  1980     add_join_distrib_right  ~> add_sup_distrib_right
  1981     add_meet_join_distribs  ~> add_sup_inf_distribs
  1982     join_eq_neg_meet        ~> sup_eq_neg_inf
  1983     meet_eq_neg_join        ~> inf_eq_neg_sup
  1984     add_eq_meet_join        ~> add_eq_inf_sup
  1985     meet_0_imp_0            ~> inf_0_imp_0
  1986     join_0_imp_0            ~> sup_0_imp_0
  1987     meet_0_eq_0             ~> inf_0_eq_0
  1988     join_0_eq_0             ~> sup_0_eq_0
  1989     neg_meet_eq_join        ~> neg_inf_eq_sup
  1990     neg_join_eq_meet        ~> neg_sup_eq_inf
  1991     join_eq_if              ~> sup_eq_if
  1992 
  1993     mono_meet               ~> mono_inf
  1994     mono_join               ~> mono_sup
  1995     meet_bool_eq            ~> inf_bool_eq
  1996     join_bool_eq            ~> sup_bool_eq
  1997     meet_fun_eq             ~> inf_fun_eq
  1998     join_fun_eq             ~> sup_fun_eq
  1999     meet_set_eq             ~> inf_set_eq
  2000     join_set_eq             ~> sup_set_eq
  2001     meet1_iff               ~> inf1_iff
  2002     meet2_iff               ~> inf2_iff
  2003     meet1I                  ~> inf1I
  2004     meet2I                  ~> inf2I
  2005     meet1D1                 ~> inf1D1
  2006     meet2D1                 ~> inf2D1
  2007     meet1D2                 ~> inf1D2
  2008     meet2D2                 ~> inf2D2
  2009     meet1E                  ~> inf1E
  2010     meet2E                  ~> inf2E
  2011     join1_iff               ~> sup1_iff
  2012     join2_iff               ~> sup2_iff
  2013     join1I1                 ~> sup1I1
  2014     join2I1                 ~> sup2I1
  2015     join1I1                 ~> sup1I1
  2016     join2I2                 ~> sup1I2
  2017     join1CI                 ~> sup1CI
  2018     join2CI                 ~> sup2CI
  2019     join1E                  ~> sup1E
  2020     join2E                  ~> sup2E
  2021 
  2022     is_meet_Meet            ~> is_meet_Inf
  2023     Meet_bool_def           ~> Inf_bool_def
  2024     Meet_fun_def            ~> Inf_fun_def
  2025     Meet_greatest           ~> Inf_greatest
  2026     Meet_lower              ~> Inf_lower
  2027     Meet_set_def            ~> Inf_set_def
  2028 
  2029     Sup_def                 ~> Sup_Inf
  2030     Sup_bool_eq             ~> Sup_bool_def
  2031     Sup_fun_eq              ~> Sup_fun_def
  2032     Sup_set_eq              ~> Sup_set_def
  2033 
  2034     listsp_meetI            ~> listsp_infI
  2035     listsp_meet_eq          ~> listsp_inf_eq
  2036 
  2037     meet_min                ~> inf_min
  2038     join_max                ~> sup_max
  2039 
  2040 * Added syntactic class "size"; overloaded constant "size" now has
  2041 type "'a::size ==> bool"
  2042 
  2043 * Internal reorganisation of `size' of datatypes: size theorems
  2044 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2045 simplification rules by default!); theorems "prod.size" now named
  2046 "*.size".
  2047 
  2048 * Class "div" now inherits from class "times" rather than "type".
  2049 INCOMPATIBILITY.
  2050 
  2051 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2052 Linorder etc.  have disappeared; operations defined in terms of
  2053 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2054 
  2055 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2056 
  2057 * HOL-Word: New extensive library and type for generic, fixed size
  2058 machine words, with arithemtic, bit-wise, shifting and rotating
  2059 operations, reflection into int, nat, and bool lists, automation for
  2060 linear arithmetic (by automatic reflection into nat or int), including
  2061 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2062 arithmetic type classes, supporting automatic simplification of
  2063 numerals on all operations.
  2064 
  2065 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2066 
  2067 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2068 
  2069 * Code generator library theories:
  2070   - Code_Integer represents HOL integers by big integer literals in target
  2071     languages.
  2072   - Code_Char represents HOL characters by character literals in target
  2073     languages.
  2074   - Code_Char_chr like Code_Char, but also offers treatment of character
  2075     codes; includes Code_Integer.
  2076   - Executable_Set allows to generate code for finite sets using lists.
  2077   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2078     denominator).
  2079   - Executable_Real implements a subset of real numbers, namly those
  2080     representable by rational numbers.
  2081   - Efficient_Nat implements natural numbers by integers, which in general will
  2082     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2083     includes Code_Integer.
  2084   - Code_Index provides an additional datatype index which is mapped to
  2085     target-language built-in integers.
  2086   - Code_Message provides an additional datatype message_string which is isomorphic to
  2087     strings; messages are mapped to target-language strings.
  2088 
  2089 * New package for inductive predicates
  2090 
  2091   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2092 
  2093     inductive
  2094       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2095       for z_1 :: U_1 and ... and z_n :: U_m
  2096     where
  2097       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2098     | ...
  2099 
  2100   with full support for type-inference, rather than
  2101 
  2102     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2103 
  2104     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2105     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2106 
  2107     inductive "s z_1 ... z_m"
  2108     intros
  2109       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2110       ...
  2111 
  2112   For backward compatibility, there is a wrapper allowing inductive
  2113   sets to be defined with the new package via
  2114 
  2115     inductive_set
  2116       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2117       for z_1 :: U_1 and ... and z_n :: U_m
  2118     where
  2119       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2120     | ...
  2121 
  2122   or
  2123 
  2124     inductive_set
  2125       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2126       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2127       for z_1 :: U_1 and ... and z_n :: U_m
  2128     where
  2129       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2130     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2131     | ...
  2132 
  2133   if the additional syntax "p ..." is required.
  2134 
  2135   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2136   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2137 
  2138   INCOMPATIBILITIES:
  2139 
  2140   - Since declaration and definition of inductive sets or predicates
  2141     is no longer separated, abbreviations involving the newly
  2142     introduced sets or predicates must be specified together with the
  2143     introduction rules after the 'where' keyword (see above), rather
  2144     than before the actual inductive definition.
  2145 
  2146   - The variables in induction and elimination rules are now
  2147     quantified in the order of their occurrence in the introduction
  2148     rules, rather than in alphabetical order. Since this may break
  2149     some proofs, these proofs either have to be repaired, e.g. by
  2150     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2151     statements of the form
  2152 
  2153       case (rule_i a_i_1 ... a_i_{k_i})
  2154 
  2155     or the old order of quantification has to be restored by explicitly adding
  2156     meta-level quantifiers in the introduction rules, i.e.
  2157 
  2158       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2159 
  2160   - The format of the elimination rules is now
  2161 
  2162       p z_1 ... z_m x_1 ... x_n ==>
  2163         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2164         ==> ... ==> P
  2165 
  2166     for predicates and
  2167 
  2168       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2169         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2170         ==> ... ==> P
  2171 
  2172     for sets rather than
  2173 
  2174       x : s z_1 ... z_m ==>
  2175         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2176         ==> ... ==> P
  2177 
  2178     This may require terms in goals to be expanded to n-tuples
  2179     (e.g. using case_tac or simplification with the split_paired_all
  2180     rule) before the above elimination rule is applicable.
  2181 
  2182   - The elimination or case analysis rules for (mutually) inductive
  2183     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2184     list of rules "p_1_..._p_k.elims" is no longer available.
  2185 
  2186 * New package "function"/"fun" for general recursive functions,
  2187 supporting mutual and nested recursion, definitions in local contexts,
  2188 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2189 for small examples, and the separate tutorial on the function
  2190 package. The old recdef "package" is still available as before, but
  2191 users are encouraged to use the new package.
  2192 
  2193 * Method "lexicographic_order" automatically synthesizes termination
  2194 relations as lexicographic combinations of size measures. 
  2195 
  2196 * Case-expressions allow arbitrary constructor-patterns (including
  2197 "_") and take their order into account, like in functional
  2198 programming.  Internally, this is translated into nested
  2199 case-expressions; missing cases are added and mapped to the predefined
  2200 constant "undefined". In complicated cases printing may no longer show
  2201 the original input but the internal form. Lambda-abstractions allow
  2202 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2203 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2204 variable.
  2205 
  2206 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2207 is an abbreviation for "of_nat :: nat => int". The simplification
  2208 rules for "of_nat" have been changed to work like "int" did
  2209 previously.  Potential INCOMPATIBILITY:
  2210   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2211   - of_nat_diff and of_nat_mult are no longer default simp rules
  2212 
  2213 * Method "algebra" solves polynomial equations over (semi)rings using
  2214 Groebner bases. The (semi)ring structure is defined by locales and the
  2215 tool setup depends on that generic context. Installing the method for
  2216 a specific type involves instantiating the locale and possibly adding
  2217 declarations for computation on the coefficients.  The method is
  2218 already instantiated for natural numbers and for the axiomatic class
  2219 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2220 CALCULEMUS 2007 for the general principles underlying this
  2221 architecture of context-aware proof-tools.
  2222 
  2223 * Method "ferrack" implements quantifier elimination over
  2224 special-purpose dense linear orders using locales (analogous to
  2225 "algebra"). The method is already installed for class
  2226 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2227 rat, etc.
  2228 
  2229 * Former constant "List.op @" now named "List.append".  Use ML
  2230 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2231 circumvent possible incompatibilities when working on ML level.
  2232 
  2233 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2234 
  2235 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2236 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2237 
  2238 * New syntax for Haskell-like list comprehension (input only), eg.
  2239 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2240 
  2241 * The special syntax for function "filter" has changed from [x :
  2242 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2243 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2244 
  2245 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2246 defined on nat only, as an abbreviation for [a..<Suc b]
  2247 INCOMPATIBILITY.
  2248 
  2249 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2250 
  2251 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2252 
  2253 * New lemma collection field_simps (an extension of ring_simps) for
  2254 manipulating (in)equations involving division. Multiplies with all
  2255 denominators that can be proved to be non-zero (in equations) or
  2256 positive/negative (in inequations).
  2257 
  2258 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2259 have been improved and renamed to ring_simps, group_simps and
  2260 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2261 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2262 
  2263 * Theory Library/Commutative_Ring: switched from recdef to function
  2264 package; constants add, mul, pow now curried.  Infix syntax for
  2265 algebraic operations.
  2266 
  2267 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2268 INCOMPATIBILITY.
  2269 
  2270 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2271 INCOMPATIBILITY.
  2272 
  2273 * HOL/records: generalised field-update to take a function on the
  2274 field rather than the new value: r(|A := x|) is translated to A_update
  2275 (K x) r The K-combinator that is internally used is called K_record.
  2276 INCOMPATIBILITY: Usage of the plain update functions has to be
  2277 adapted.
  2278  
  2279 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2280 * x = 0, which are required for a semiring.  Richer structures do not
  2281 inherit from semiring_0 anymore, because this property is a theorem
  2282 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2283 there is more to prove, but this is mostly trivial.
  2284 
  2285 * Class "recpower" is generalized to arbitrary monoids, not just
  2286 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2287 commutativity or semiring properties additionally.
  2288 
  2289 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2290 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2291 better use 'abbreviation'.
  2292 
  2293 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2294 
  2295 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2296 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2297 significant changes for setting up numeral syntax for types:
  2298   - New constants Numeral.pred and Numeral.succ instead
  2299       of former Numeral.bin_pred and Numeral.bin_succ.
  2300   - Use integer operations instead of bin_add, bin_mult and so on.
  2301   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2302   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2303 
  2304 See src/HOL/Integ/IntArith.thy for an example setup.
  2305 
  2306 * Command 'normal_form' computes the normal form of a term that may
  2307 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2308 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2309 heavy-duty computations because the functions are compiled to ML
  2310 first.  Correspondingly, a method "normalization" is provided.  See
  2311 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2312 
  2313 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2314 25 like -->); output depends on the "iff" print_mode, the default is
  2315 "A = B" (with priority 50).
  2316 
  2317 * Relations less (<) and less_eq (<=) are also available on type bool.
  2318 Modified syntax to disallow nesting without explicit parentheses,
  2319 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2320 INCOMPATIBILITY.
  2321 
  2322 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2323 
  2324 * Relation composition operator "op O" now has precedence 75 and binds
  2325 stronger than union and intersection. INCOMPATIBILITY.
  2326 
  2327 * The old set interval syntax "{m..n(}" (and relatives) has been
  2328 removed.  Use "{m..<n}" (and relatives) instead.
  2329 
  2330 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2331 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2332 ``declare [[simproc del: neq]]''.
  2333 
  2334 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2335 True/False.
  2336 
  2337 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2338 
  2339 * Theorem setsum_mult renamed to setsum_right_distrib.
  2340 
  2341 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2342 ``rule'' method.
  2343 
  2344 * Reimplemented methods "sat" and "satx", with several improvements:
  2345 goals no longer need to be stated as "<prems> ==> False", equivalences
  2346 (i.e. "=" on type bool) are handled, variable names of the form
  2347 "lit_<n>" are no longer reserved, significant speedup.
  2348 
  2349 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2350 zChaff is still supported as well.
  2351 
  2352 * 'inductive' and 'datatype': provide projections of mutual rules,
  2353 bundled as foo_bar.inducts;
  2354 
  2355 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2356 Library.
  2357 
  2358 * Library: moved theory Accessible_Part to main HOL.
  2359 
  2360 * Library: added theory Coinductive_List of potentially infinite lists
  2361 as greatest fixed-point.
  2362 
  2363 * Library: added theory AssocList which implements (finite) maps as
  2364 association lists.
  2365 
  2366 * Method "evaluation" solves goals (i.e. a boolean expression)
  2367 efficiently by compiling it to ML.  The goal is "proved" (via an
  2368 oracle) if it evaluates to True.
  2369 
  2370 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2371 also when invoked by the simplifier.  This results in the Simplifier
  2372 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2373 Configuration option fast_arith_split_limit=0 recovers the old
  2374 behavior.
  2375 
  2376 * Support for hex (0x20) and binary (0b1001) numerals.
  2377 
  2378 * New method: reify eqs (t), where eqs are equations for an
  2379 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2380 parameter, computes a term s::'b and a list xs::'a list and proves the
  2381 theorem I xs s = t. This is also known as reification or quoting. The
  2382 resulting theorem is applied to the subgoal to substitute t with I xs
  2383 s.  If t is omitted, the subgoal itself is reified.
  2384 
  2385 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2386 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2387 where f is supposed to be a computable function (in the sense of code
  2388 generattion). The method uses reify to compute s and xs as above then
  2389 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2390 r and finally gets the theorem t = r, which is again applied to the
  2391 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2392 
  2393 * Reflection: Automatic reification now handels binding, an example is
  2394 available in src/HOL/ex/ReflectionEx.thy
  2395 
  2396 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2397 command 'statespace' that is similar to 'record', but introduces an
  2398 abstract specification based on the locale infrastructure instead of
  2399 HOL types.  This leads to extra flexibility in composing state spaces,
  2400 in particular multiple inheritance and renaming of components.
  2401 
  2402 
  2403 *** HOL-Complex ***
  2404 
  2405 * Hyperreal: Functions root and sqrt are now defined on negative real
  2406 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2407 Nonnegativity side conditions have been removed from many lemmas, so
  2408 that more subgoals may now be solved by simplification; potential
  2409 INCOMPATIBILITY.
  2410 
  2411 * Real: new type classes formalize real normed vector spaces and
  2412 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2413 and norm :: 'a => real.
  2414 
  2415 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2416 reals into other types. The overloaded constant Reals :: 'a set is now
  2417 defined as range of_real; potential INCOMPATIBILITY.
  2418 
  2419 * Real: proper support for ML code generation, including 'quickcheck'.
  2420 Reals are implemented as arbitrary precision rationals.
  2421 
  2422 * Hyperreal: Several constants that previously worked only for the
  2423 reals have been generalized, so they now work over arbitrary vector
  2424 spaces. Type annotations may need to be added in some cases; potential
  2425 INCOMPATIBILITY.
  2426 
  2427   Infinitesimal  :: ('a::real_normed_vector) star set
  2428   HFinite        :: ('a::real_normed_vector) star set
  2429   HInfinite      :: ('a::real_normed_vector) star set
  2430   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2431   monad          :: ('a::real_normed_vector) star => 'a star set
  2432   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2433   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2434   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2435   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2436   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2437   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2438   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2439   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2440   sgn            :: 'a::real_normed_vector => 'a
  2441   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2442 
  2443 * Complex: Some complex-specific constants are now abbreviations for
  2444 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2445 hnorm.  Other constants have been entirely removed in favor of the
  2446 polymorphic versions (INCOMPATIBILITY):
  2447 
  2448   approx        <-- capprox
  2449   HFinite       <-- CFinite
  2450   HInfinite     <-- CInfinite
  2451   Infinitesimal <-- CInfinitesimal
  2452   monad         <-- cmonad
  2453   galaxy        <-- cgalaxy
  2454   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2455   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2456   (ns)deriv     <-- (ns)cderiv
  2457 
  2458 
  2459 *** HOL-Algebra ***
  2460 
  2461 * Formalisation of ideals and the quotient construction over rings.
  2462 
  2463 * Order and lattice theory no longer based on records.
  2464 INCOMPATIBILITY.
  2465 
  2466 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2467 greatest_closed.  INCOMPATIBILITY.
  2468 
  2469 * Method algebra is now set up via an attribute.  For examples see
  2470 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2471 of algebraic structures.
  2472 
  2473 * Renamed theory CRing to Ring.
  2474 
  2475 
  2476 *** HOL-Nominal ***
  2477 
  2478 * Substantial, yet incomplete support for nominal datatypes (binding
  2479 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2480 src/HOL/Nominal/Examples.  Prospective users should consult
  2481 http://isabelle.in.tum.de/nominal/
  2482 
  2483 
  2484 *** ML ***
  2485 
  2486 * ML basics: just one true type int, which coincides with IntInf.int
  2487 (even on SML/NJ).
  2488 
  2489 * ML within Isar: antiquotations allow to embed statically-checked
  2490 formal entities in the source, referring to the context available at
  2491 compile-time.  For example:
  2492 
  2493 ML {* @{sort "{zero,one}"} *}
  2494 ML {* @{typ "'a => 'b"} *}
  2495 ML {* @{term "%x. x"} *}
  2496 ML {* @{prop "x == y"} *}
  2497 ML {* @{ctyp "'a => 'b"} *}
  2498 ML {* @{cterm "%x. x"} *}
  2499 ML {* @{cprop "x == y"} *}
  2500 ML {* @{thm asm_rl} *}
  2501 ML {* @{thms asm_rl} *}
  2502 ML {* @{type_name c} *}
  2503 ML {* @{type_syntax c} *}
  2504 ML {* @{const_name c} *}
  2505 ML {* @{const_syntax c} *}
  2506 ML {* @{context} *}
  2507 ML {* @{theory} *}
  2508 ML {* @{theory Pure} *}
  2509 ML {* @{theory_ref} *}
  2510 ML {* @{theory_ref Pure} *}
  2511 ML {* @{simpset} *}
  2512 ML {* @{claset} *}
  2513 ML {* @{clasimpset} *}
  2514 
  2515 The same works for sources being ``used'' within an Isar context.
  2516 
  2517 * ML in Isar: improved error reporting; extra verbosity with
  2518 ML_Context.trace enabled.
  2519 
  2520 * Pure/General/table.ML: the join operations now works via exceptions
  2521 DUP/SAME instead of type option. This is simpler in simple cases, and
  2522 admits slightly more efficient complex applications.
  2523 
  2524 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2525 use Context.generic instead of just theory.
  2526 
  2527 * Pure: datatype Context.generic joins theory/Proof.context and
  2528 provides some facilities for code that works in either kind of
  2529 context, notably GenericDataFun for uniform theory and proof data.
  2530 
  2531 * Pure: simplified internal attribute type, which is now always
  2532 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2533 local (Proof.context) attributes have been discontinued, while
  2534 minimizing code duplication. Thm.rule_attribute and
  2535 Thm.declaration_attribute build canonical attributes; see also structure
  2536 Context for further operations on Context.generic, notably
  2537 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2538 declarations and definitions.
  2539 
  2540 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2541 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2542 init only required for impure data. INCOMPATIBILITY: empty really need
  2543 to be empty (no dependencies on theory content!)
  2544 
  2545 * Pure/kernel: consts certification ignores sort constraints given in
  2546 signature declarations. (This information is not relevant to the
  2547 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2548 potential INCOMPATIBILITY.
  2549 
  2550 * Pure: axiomatic type classes are now purely definitional, with
  2551 explicit proofs of class axioms and super class relations performed
  2552 internally. See Pure/axclass.ML for the main internal interfaces --
  2553 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2554 AxClass.axiomatize_class/classrel/arity supersede
  2555 Sign.add_classes/classrel/arities.
  2556 
  2557 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2558 global/local versions on theory vs. Proof.context have been
  2559 discontinued; Attrib.syntax and Method.syntax have been adapted
  2560 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2561 attributes, methods, etc.
  2562 
  2563 * Pure: several functions of signature "... -> theory -> theory * ..."
  2564 have been reoriented to "... -> theory -> ... * theory" in order to
  2565 allow natural usage in combination with the ||>, ||>>, |-> and
  2566 fold_map combinators.
  2567 
  2568 * Pure: official theorem names (closed derivations) and additional
  2569 comments (tags) are now strictly separate.  Name hints -- which are
  2570 maintained as tags -- may be attached any time without affecting the
  2571 derivation.
  2572 
  2573 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2574 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2575 achieve the old behaviour.
  2576 
  2577 * Pure: the "Goal" constant is now called "prop", supporting a
  2578 slightly more general idea of ``protecting'' meta-level rule
  2579 statements.
  2580 
  2581 * Pure: Logic.(un)varify only works in a global context, which is now
  2582 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2583 Logic.legacy_(un)varify as temporary workaround.
  2584 
  2585 * Pure: structure Name provides scalable operations for generating
  2586 internal variable names, notably Name.variants etc.  This replaces
  2587 some popular functions from term.ML:
  2588 
  2589   Term.variant		->  Name.variant
  2590   Term.variantlist	->  Name.variant_list
  2591   Term.invent_names	->  Name.invent_list
  2592 
  2593 Note that low-level renaming rarely occurs in new code -- operations
  2594 from structure Variable are used instead (see below).
  2595 
  2596 * Pure: structure Variable provides fundamental operations for proper
  2597 treatment of fixed/schematic variables in a context.  For example,
  2598 Variable.import introduces fixes for schematics of given facts and
  2599 Variable.export reverses the effect (up to renaming) -- this replaces
  2600 various freeze_thaw operations.
  2601 
  2602 * Pure: structure Goal provides simple interfaces for
  2603 init/conclude/finish and tactical prove operations (replacing former
  2604 Tactic.prove).  Goal.prove is the canonical way to prove results
  2605 within a given context; Goal.prove_global is a degraded version for
  2606 theory level goals, including a global Drule.standard.  Note that
  2607 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2608 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2609 in a locale context).
  2610 
  2611 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2612 and type checking (Syntax.check_term etc.), with common combinations
  2613 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2614 which are considered legacy and await removal.
  2615 
  2616 * Pure/Syntax: generic interfaces for type unchecking
  2617 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2618 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2619 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2620 available for convenience, but refer to the very same operations using
  2621 a mere theory instead of a full context.
  2622 
  2623 * Isar: simplified treatment of user-level errors, using exception
  2624 ERROR of string uniformly.  Function error now merely raises ERROR,
  2625 without any side effect on output channels.  The Isar toplevel takes
  2626 care of proper display of ERROR exceptions.  ML code may use plain
  2627 handle/can/try; cat_error may be used to concatenate errors like this:
  2628 
  2629   ... handle ERROR msg => cat_error msg "..."
  2630 
  2631 Toplevel ML code (run directly or through the Isar toplevel) may be
  2632 embedded into the Isar toplevel with exception display/debug like
  2633 this:
  2634 
  2635   Isar.toplevel (fn () => ...)
  2636 
  2637 INCOMPATIBILITY, removed special transform_error facilities, removed
  2638 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2639 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2640 -- use plain ERROR instead.
  2641 
  2642 * Isar: theory setup now has type (theory -> theory), instead of a
  2643 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2644 
  2645 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2646 ProofContext.debug/verbose flags.
  2647 
  2648 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2649 theory before entering a proof state.  Transactions now always see a
  2650 quasi-functional intermediate checkpoint, both in interactive and
  2651 batch mode.
  2652 
  2653 * Isar: simplified interfaces for outer syntax.  Renamed
  2654 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2655 OuterSyntax.add_parsers -- this functionality is now included in
  2656 OuterSyntax.command etc.  INCOMPATIBILITY.
  2657 
  2658 * Simplifier: the simpset of a running simplification process now
  2659 contains a proof context (cf. Simplifier.the_context), which is the
  2660 very context that the initial simpset has been retrieved from (by
  2661 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2662 (solver, looper etc.) may depend on arbitrary proof data.
  2663 
  2664 * Simplifier.inherit_context inherits the proof context (plus the
  2665 local bounds) of the current simplification process; any simproc
  2666 etc. that calls the Simplifier recursively should do this!  Removed
  2667 former Simplifier.inherit_bounds, which is already included here --
  2668 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2669 specify an explicit context using Simplifier.context/theory_context.
  2670 
  2671 * Simplifier/Classical Reasoner: more abstract interfaces
  2672 change_simpset/claset for modifying the simpset/claset reference of a
  2673 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2674 INCOMPATIBILITY.
  2675 
  2676 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2677 "Trueprop" etc.
  2678 
  2679 
  2680 *** System ***
  2681 
  2682 * settings: the default heap location within ISABELLE_HOME_USER now
  2683 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2684 Isabelle installations.
  2685 
  2686 * isabelle-process: option -S (secure mode) disables some critical
  2687 operations, notably runtime compilation and evaluation of ML source
  2688 code.
  2689 
  2690 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2691 
  2692 * Support for parallel execution, using native multicore support of
  2693 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2694 independent theories, according to the given theory header
  2695 specifications. The maximum number of worker threads is specified via
  2696 usedir option -M or the "max-threads" setting in Proof General. A
  2697 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2698 to 6 on a 8-core machine.  User-code needs to observe certain
  2699 guidelines for thread-safe programming, see appendix A in the Isar
  2700 Implementation manual.
  2701 
  2702 
  2703 
  2704 New in Isabelle2005 (October 2005)
  2705 ----------------------------------
  2706 
  2707 *** General ***
  2708 
  2709 * Theory headers: the new header syntax for Isar theories is
  2710 
  2711   theory <name>
  2712   imports <theory1> ... <theoryN>
  2713   uses <file1> ... <fileM>
  2714   begin
  2715 
  2716 where the 'uses' part is optional.  The previous syntax
  2717 
  2718   theory <name> = <theory1> + ... + <theoryN>:
  2719 
  2720 will disappear in the next release.  Use isatool fixheaders to convert
  2721 existing theory files.  Note that there is no change in ancient
  2722 non-Isar theories now, but these will disappear soon.
  2723 
  2724 * Theory loader: parent theories can now also be referred to via
  2725 relative and absolute paths.
  2726 
  2727 * Command 'find_theorems' searches for a list of criteria instead of a
  2728 list of constants. Known criteria are: intro, elim, dest, name:string,
  2729 simp:term, and any term. Criteria can be preceded by '-' to select
  2730 theorems that do not match. Intro, elim, dest select theorems that
  2731 match the current goal, name:s selects theorems whose fully qualified
  2732 name contain s, and simp:term selects all simplification rules whose
  2733 lhs match term.  Any other term is interpreted as pattern and selects
  2734 all theorems matching the pattern. Available in ProofGeneral under
  2735 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2736 
  2737   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2738 
  2739 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2740 matching the current goal as introduction rule and not having "HOL."
  2741 in their name (i.e. not being defined in theory HOL).
  2742 
  2743 * Command 'thms_containing' has been discontinued in favour of
  2744 'find_theorems'; INCOMPATIBILITY.
  2745 
  2746 * Communication with Proof General is now 8bit clean, which means that
  2747 Unicode text in UTF-8 encoding may be used within theory texts (both
  2748 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2749 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2750 
  2751   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2752   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2753 
  2754 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2755 Classical Reasoner.  Typical big applications run around 2 times
  2756 faster.
  2757 
  2758 
  2759 *** Document preparation ***
  2760 
  2761 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2762 of raw sources.  Only those symbols that do not require additional
  2763 LaTeX packages (depending on comments in isabellesym.sty) are
  2764 displayed properly, everything else is left verbatim.  isatool display
  2765 and isatool print are used as front ends (these are subject to the
  2766 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2767 
  2768 * Command tags control specific markup of certain regions of text,
  2769 notably folding and hiding.  Predefined tags include "theory" (for
  2770 theory begin and end), "proof" for proof commands, and "ML" for
  2771 commands involving ML code; the additional tags "visible" and
  2772 "invisible" are unused by default.  Users may give explicit tag
  2773 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2774 interpretation of tags is determined by the LaTeX job during document
  2775 preparation: see option -V of isatool usedir, or options -n and -t of
  2776 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2777 \isadroptag.
  2778 
  2779 Several document versions may be produced at the same time via isatool
  2780 usedir (the generated index.html will link all of them).  Typical
  2781 specifications include ''-V document=theory,proof,ML'' to present
  2782 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2783 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2784 these parts without any formal replacement text.  The Isabelle site
  2785 default settings produce ''document'' and ''outline'' versions as
  2786 specified above.
  2787 
  2788 * Several new antiquotations:
  2789 
  2790   @{term_type term} prints a term with its type annotated;
  2791 
  2792   @{typeof term} prints the type of a term;
  2793 
  2794   @{const const} is the same as @{term const}, but checks that the
  2795   argument is a known logical constant;
  2796 
  2797   @{term_style style term} and @{thm_style style thm} print a term or
  2798   theorem applying a "style" to it
  2799 
  2800   @{ML text}
  2801 
  2802 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2803 definitions, equations, inequations etc., 'concl' printing only the
  2804 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2805 to print the specified premise.  TermStyle.add_style provides an ML
  2806 interface for introducing further styles.  See also the "LaTeX Sugar"
  2807 document practical applications.  The ML antiquotation prints
  2808 type-checked ML expressions verbatim.
  2809 
  2810 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2811 and 'text' support optional locale specification '(in loc)', which
  2812 specifies the default context for interpreting antiquotations.  For
  2813 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2814 
  2815 * Option 'locale=NAME' of antiquotations specifies an alternative
  2816 context interpreting the subsequent argument.  For example: @{thm
  2817 [locale=lattice] inf_assoc}.
  2818 
  2819 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2820 a proof context.
  2821 
  2822 * Proper output of antiquotations for theory commands involving a
  2823 proof context (such as 'locale' or 'theorem (in loc) ...').
  2824 
  2825 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2826 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2827 
  2828 * isatool usedir: new option -C (default true) controls whether option
  2829 -D should include a copy of the original document directory; -C false
  2830 prevents unwanted effects such as copying of administrative CVS data.
  2831 
  2832 
  2833 *** Pure ***
  2834 
  2835 * Considerably improved version of 'constdefs' command.  Now performs
  2836 automatic type-inference of declared constants; additional support for
  2837 local structure declarations (cf. locales and HOL records), see also
  2838 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2839 sequential dependencies of definitions within a single 'constdefs'
  2840 section; moreover, the declared name needs to be an identifier.  If
  2841 all fails, consider to fall back on 'consts' and 'defs' separately.
  2842 
  2843 * Improved indexed syntax and implicit structures.  First of all,
  2844 indexed syntax provides a notational device for subscripted
  2845 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2846 expressions.  Secondly, in a local context with structure
  2847 declarations, number indexes \<^sub>n or the empty index (default
  2848 number 1) refer to a certain fixed variable implicitly; option
  2849 show_structs controls printing of implicit structures.  Typical
  2850 applications of these concepts involve record types and locales.
  2851 
  2852 * New command 'no_syntax' removes grammar declarations (and
  2853 translations) resulting from the given syntax specification, which is
  2854 interpreted in the same manner as for the 'syntax' command.
  2855 
  2856 * 'Advanced' translation functions (parse_translation etc.) may depend
  2857 on the signature of the theory context being presently used for
  2858 parsing/printing, see also isar-ref manual.
  2859 
  2860 * Improved 'oracle' command provides a type-safe interface to turn an
  2861 ML expression of type theory -> T -> term into a primitive rule of
  2862 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2863 is already included here); see also FOL/ex/IffExample.thy;
  2864 INCOMPATIBILITY.
  2865 
  2866 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2867 before); "cI" is no longer bound, use "c.intro" instead.
  2868 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2869 axclasses vs. locales.
  2870 
  2871 * Improved internal renaming of symbolic identifiers -- attach primes
  2872 instead of base 26 numbers.
  2873 
  2874 * New flag show_question_marks controls printing of leading question
  2875 marks in schematic variable names.
  2876 
  2877 * In schematic variable names, *any* symbol following \<^isub> or
  2878 \<^isup> is now treated as part of the base name.  For example, the
  2879 following works without printing of awkward ".0" indexes:
  2880 
  2881   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2882     by simp
  2883 
  2884 * Inner syntax includes (*(*nested*) comments*).
  2885 
  2886 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2887 annotations as "(00...)".
  2888 
  2889 * Clear separation of logical types and nonterminals, where the latter
  2890 may only occur in 'syntax' specifications or type abbreviations.
  2891 Before that distinction was only partially implemented via type class
  2892 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2893 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2894 exotic syntax specifications may require further adaption
  2895 (e.g. Cube/Cube.thy).
  2896 
  2897 * Removed obsolete type class "logic", use the top sort {} instead.
  2898 Note that non-logical types should be declared as 'nonterminals'
  2899 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2900 specifications.
  2901 
  2902 * Attributes 'induct' and 'cases': type or set names may now be
  2903 locally fixed variables as well.
  2904 
  2905 * Simplifier: can now control the depth to which conditional rewriting
  2906 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2907 Limit.
  2908 
  2909 * Simplifier: simplification procedures may now take the current
  2910 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2911 interface), which is very useful for calling the Simplifier
  2912 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2913 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2914 low-level mk_simproc no longer applies Logic.varify internally, to
  2915 allow for use in a context of fixed variables.
  2916 
  2917 * thin_tac now works even if the assumption being deleted contains !!
  2918 or ==>.  More generally, erule now works even if the major premise of
  2919 the elimination rule contains !! or ==>.
  2920 
  2921 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2922 
  2923 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2924 from Pure, which contains all common declarations already.  Both
  2925 theories are defined via plain Isabelle/Isar .thy files.
  2926 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2927 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2928 use isatool fixcpure to adapt your theory and ML sources.
  2929 
  2930 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2931 selections of theorems in named facts via index ranges.
  2932 
  2933 * 'print_theorems': in theory mode, really print the difference
  2934 wrt. the last state (works for interactive theory development only),
  2935 in proof mode print all local facts (cf. 'print_facts');
  2936 
  2937 * 'hide': option '(open)' hides only base names.
  2938 
  2939 * More efficient treatment of intermediate checkpoints in interactive
  2940 theory development.
  2941 
  2942 * Code generator is now invoked via code_module (incremental code
  2943 generation) and code_library (modular code generation, ML structures
  2944 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2945 must be quoted when used as identifiers.
  2946 
  2947 * New 'value' command for reading, evaluating and printing terms using
  2948 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2949 quoted when used as identifier.
  2950 
  2951 
  2952 *** Locales ***
  2953 
  2954 * New commands for the interpretation of locale expressions in
  2955 theories (1), locales (2) and proof contexts (3).  These generate
  2956 proof obligations from the expression specification.  After the
  2957 obligations have been discharged, theorems of the expression are added
  2958 to the theory, target locale or proof context.  The synopsis of the
  2959 commands is a follows:
  2960 
  2961   (1) interpretation expr inst
  2962   (2) interpretation target < expr
  2963   (3) interpret expr inst
  2964 
  2965 Interpretation in theories and proof contexts require a parameter
  2966 instantiation of terms from the current context.  This is applied to
  2967 specifications and theorems of the interpreted expression.
  2968 Interpretation in locales only permits parameter renaming through the
  2969 locale expression.  Interpretation is smart in that interpretations
  2970 that are active already do not occur in proof obligations, neither are
  2971 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2972 inspect active interpretations of a particular locale.  For details,
  2973 see the Isar Reference manual.  Examples can be found in
  2974 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2975 
  2976 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2977 'interpret' instead.
  2978 
  2979 * New context element 'constrains' for adding type constraints to
  2980 parameters.
  2981 
  2982 * Context expressions: renaming of parameters with syntax
  2983 redeclaration.
  2984 
  2985 * Locale declaration: 'includes' disallowed.
  2986 
  2987 * Proper static binding of attribute syntax -- i.e. types / terms /
  2988 facts mentioned as arguments are always those of the locale definition
  2989 context, independently of the context of later invocations.  Moreover,
  2990 locale operations (renaming and type / term instantiation) are applied
  2991 to attribute arguments as expected.
  2992 
  2993 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2994 actual attributes; rare situations may require Attrib.attribute to
  2995 embed those attributes into Attrib.src that lack concrete syntax.
  2996 Attribute implementations need to cooperate properly with the static
  2997 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2998 Attrib.XXX_thm etc. already do the right thing without further
  2999 intervention.  Only unusual applications -- such as "where" or "of"
  3000 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  3001 on the context and the facts involved -- may have to assign parsed
  3002 values to argument tokens explicitly.
  3003 
  3004 * Changed parameter management in theorem generation for long goal
  3005 statements with 'includes'.  INCOMPATIBILITY: produces a different
  3006 theorem statement in rare situations.
  3007 
  3008 * Locale inspection command 'print_locale' omits notes elements.  Use
  3009 'print_locale!' to have them included in the output.
  3010 
  3011 
  3012 *** Provers ***
  3013 
  3014 * Provers/hypsubst.ML: improved version of the subst method, for
  3015 single-step rewriting: it now works in bound variable contexts. New is
  3016 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  3017 rewrite a different subterm than the original subst method, which is
  3018 still available as 'simplesubst'.
  3019 
  3020 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  3021 and quasi orders.
  3022 
  3023 * Provers/trancl.ML: new transitivity reasoner for transitive and
  3024 reflexive-transitive closure of relations.
  3025 
  3026 * Provers/blast.ML: new reference depth_limit to make blast's depth
  3027 limit (previously hard-coded with a value of 20) user-definable.
  3028 
  3029 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  3030 is peformed already.  Object-logics merely need to finish their
  3031 initial simpset configuration as before.  INCOMPATIBILITY.
  3032 
  3033 
  3034 *** HOL ***
  3035 
  3036 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3037 
  3038   syntax (epsilon)
  3039     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3040 
  3041 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3042 and x-symbol; use option '-m epsilon' to get it actually printed.
  3043 Moreover, the mathematically important symbolic identifier \<epsilon>
  3044 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3045 
  3046 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3047 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3048 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3049 support corresponding Isar calculations.
  3050 
  3051 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3052 instead of ":".
  3053 
  3054 * theory SetInterval: changed the syntax for open intervals:
  3055 
  3056   Old       New
  3057   {..n(}    {..<n}
  3058   {)n..}    {n<..}
  3059   {m..n(}   {m..<n}
  3060   {)m..n}   {m<..n}
  3061   {)m..n(}  {m<..<n}
  3062 
  3063 The old syntax is still supported but will disappear in the next
  3064 release.  For conversion use the following Emacs search and replace
  3065 patterns (these are not perfect but work quite well):
  3066 
  3067   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3068   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3069 
  3070 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3071 equalities in commutative rings; method 'algebra' provides a generic
  3072 interface.
  3073 
  3074 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3075 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3076 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3077 be a tuple pattern.
  3078 
  3079 Some new syntax forms are available:
  3080 
  3081   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3082   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3083   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3084   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3085 
  3086 The latter form "\<Sum>x < k. e" used to be based on a separate
  3087 function "Summation", which has been discontinued.
  3088 
  3089 * theory Finite_Set: in structured induction proofs, the insert case
  3090 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3091 (insert F x)'.
  3092 
  3093 * The 'refute' command has been extended to support a much larger
  3094 fragment of HOL, including axiomatic type classes, constdefs and
  3095 typedefs, inductive datatypes and recursion.
  3096 
  3097 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3098 Requires zChaff with proof generation to be installed.  See
  3099 HOL/ex/SAT_Examples.thy for examples.
  3100 
  3101 * Datatype induction via method 'induct' now preserves the name of the
  3102 induction variable. For example, when proving P(xs::'a list) by
  3103 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3104 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3105 in unstructured proof scripts.
  3106 
  3107 * Reworked implementation of records.  Improved scalability for
  3108 records with many fields, avoiding performance problems for type
  3109 inference. Records are no longer composed of nested field types, but
  3110 of nested extension types. Therefore the record type only grows linear
  3111 in the number of extensions and not in the number of fields.  The
  3112 top-level (users) view on records is preserved.  Potential
  3113 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3114 old record representation. The type generated for a record is called
  3115 <record_name>_ext_type.
  3116 
  3117 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3118 proofs triggered by a record definition or a simproc (if
  3119 quick_and_dirty is enabled).  Definitions of large records can take
  3120 quite long.
  3121 
  3122 New simproc record_upd_simproc for simplification of multiple record
  3123 updates enabled by default.  Moreover, trivial updates are also
  3124 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3125 occasionally, since simplification is more powerful by default.
  3126 
  3127 * typedef: proper support for polymorphic sets, which contain extra
  3128 type-variables in the term.
  3129 
  3130 * Simplifier: automatically reasons about transitivity chains
  3131 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3132 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3133 old proofs break occasionally as simplification may now solve more
  3134 goals than previously.
  3135 
  3136 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3137 present.  Works for all partial orders (class "order"), in particular
  3138 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3139 just like y <= x.
  3140 
  3141 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3142 bound variable or a constant then the let is unfolded.  Otherwise
  3143 first a is simplified to b, and then f b is simplified to g. If
  3144 possible we abstract b from g arriving at "let x = b in h x",
  3145 otherwise we unfold the let and arrive at g.  The simproc can be
  3146 enabled/disabled by the reference use_let_simproc.  Potential
  3147 INCOMPATIBILITY since simplification is more powerful by default.
  3148 
  3149 * Classical reasoning: the meson method now accepts theorems as arguments.
  3150 
  3151 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3152 jobs to provide advice on the provability of subgoals.
  3153 
  3154 * Theory OrderedGroup and Ring_and_Field: various additions and
  3155 improvements to faciliate calculations involving equalities and
  3156 inequalities.
  3157 
  3158 The following theorems have been eliminated or modified
  3159 (INCOMPATIBILITY):
  3160 
  3161   abs_eq             now named abs_of_nonneg
  3162   abs_of_ge_0        now named abs_of_nonneg
  3163   abs_minus_eq       now named abs_of_nonpos
  3164   imp_abs_id         now named abs_of_nonneg
  3165   imp_abs_neg_id     now named abs_of_nonpos
  3166   mult_pos           now named mult_pos_pos
  3167   mult_pos_le        now named mult_nonneg_nonneg
  3168   mult_pos_neg_le    now named mult_nonneg_nonpos
  3169   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3170   mult_neg           now named mult_neg_neg
  3171   mult_neg_le        now named mult_nonpos_nonpos
  3172 
  3173 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3174      
  3175      zero_le_square
  3176      not_square_less_zero 
  3177 
  3178   The following lemmas have been deleted from Real/RealPow:
  3179   
  3180      realpow_zero_zero
  3181      realpow_two
  3182      realpow_less
  3183      zero_le_power
  3184      realpow_two_le
  3185      abs_realpow_two
  3186      realpow_two_abs     
  3187 
  3188 * Theory Parity: added rules for simplifying exponents.
  3189 
  3190 * Theory List:
  3191 
  3192 The following theorems have been eliminated or modified
  3193 (INCOMPATIBILITY):
  3194 
  3195   list_all_Nil       now named list_all.simps(1)
  3196   list_all_Cons      now named list_all.simps(2)
  3197   list_all_conv      now named list_all_iff
  3198   set_mem_eq         now named mem_iff
  3199 
  3200 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3201 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3202 
  3203 
  3204 *** HOL-Complex ***
  3205 
  3206 * Theory RealDef: better support for embedding natural numbers and
  3207 integers in the reals.
  3208 
  3209 The following theorems have been eliminated or modified
  3210 (INCOMPATIBILITY):
  3211 
  3212   exp_ge_add_one_self  now requires no hypotheses
  3213   real_of_int_add      reversed direction of equality (use [symmetric])
  3214   real_of_int_minus    reversed direction of equality (use [symmetric])
  3215   real_of_int_diff     reversed direction of equality (use [symmetric])
  3216   real_of_int_mult     reversed direction of equality (use [symmetric])
  3217 
  3218 * Theory RComplete: expanded support for floor and ceiling functions.
  3219 
  3220 * Theory Ln is new, with properties of the natural logarithm
  3221 
  3222 * Hyperreal: There is a new type constructor "star" for making
  3223 nonstandard types.  The old type names are now type synonyms:
  3224 
  3225   hypreal = real star
  3226   hypnat = nat star
  3227   hcomplex = complex star
  3228 
  3229 * Hyperreal: Many groups of similarly-defined constants have been
  3230 replaced by polymorphic versions (INCOMPATIBILITY):
  3231 
  3232   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3233 
  3234   starset      <-- starsetNat, starsetC
  3235   *s*          <-- *sNat*, *sc*
  3236   starset_n    <-- starsetNat_n, starsetC_n
  3237   *sn*         <-- *sNatn*, *scn*
  3238   InternalSets <-- InternalNatSets, InternalCSets
  3239 
  3240   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3241   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3242   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3243   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3244   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3245 
  3246 * Hyperreal: Many type-specific theorems have been removed in favor of
  3247 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3248 
  3249   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3250   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3251   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3252   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3253   right_minus <-- hypreal_add_minus
  3254   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3255   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3256   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3257   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3258   mult_1_right <-- hcomplex_mult_one_right
  3259   mult_zero_left <-- hcomplex_mult_zero_left
  3260   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3261   right_distrib <-- hypnat_add_mult_distrib2
  3262   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3263   right_inverse <-- hypreal_mult_inverse
  3264   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3265   order_refl <-- {hypreal,hypnat}_le_refl
  3266   order_trans <-- {hypreal,hypnat}_le_trans
  3267   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3268   order_less_le <-- {hypreal,hypnat}_less_le
  3269   linorder_linear <-- {hypreal,hypnat}_le_linear
  3270   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3271   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3272   add_nonneg_nonneg <-- hypreal_le_add_order
  3273 
  3274 * Hyperreal: Separate theorems having to do with type-specific
  3275 versions of constants have been merged into theorems that apply to the
  3276 new polymorphic constants (INCOMPATIBILITY):
  3277 
  3278   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3279   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3280   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3281   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3282   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3283   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3284   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3285   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3286   STAR_diff <-- {STAR,STARC}_diff
  3287   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3288     STARC_hcomplex_of_complex}_image_subset
  3289   starset_n_Un <-- starset{Nat,C}_n_Un
  3290   starset_n_Int <-- starset{Nat,C}_n_Int
  3291   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3292   starset_n_diff <-- starset{Nat,C}_n_diff
  3293   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3294   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3295   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3296   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3297   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3298   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3299   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3300   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3301   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3302   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3303   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3304   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3305   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3306   starfun_diff <-- starfun{C,RC,CR}_diff
  3307   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3308   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3309   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3310   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3311   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3312   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3313   starfun_Id <-- starfunC_Id
  3314   starfun_approx <-- starfun{Nat,CR}_approx
  3315   starfun_capprox <-- starfun{C,RC}_capprox
  3316   starfun_abs <-- starfunNat_rabs
  3317   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3318   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3319   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3320   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3321   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3322   starfun_add_approx <-- starfunCR_add_approx
  3323   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3324   starfun_divide <-- starfun{C,CR,RC}_divide
  3325   starfun_n <-- starfun{Nat,C}_n
  3326   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3327   starfun_n_add <-- starfun{Nat,C}_n_add
  3328   starfun_n_add_minus <-- starfunNat_n_add_minus
  3329   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3330   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3331   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3332 
  3333   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3334   star_n_minus <-- {hypreal,hcomplex}_minus
  3335   star_n_diff <-- {hypreal,hcomplex}_diff
  3336   star_n_mult <-- {hypreal,hcomplex}_mult
  3337   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3338   star_n_le <-- {hypreal,hypnat}_le
  3339   star_n_less <-- {hypreal,hypnat}_less
  3340   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3341   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3342   star_n_abs <-- hypreal_hrabs
  3343   star_n_divide <-- hcomplex_divide
  3344 
  3345   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3346   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3347   star_of_diff <-- hypreal_of_real_diff
  3348   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3349   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3350   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3351   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3352   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3353   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3354   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3355   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3356   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3357   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3358   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3359   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3360   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3361   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3362   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3363   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3364   star_of_power <-- hypreal_of_real_power
  3365   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3366 
  3367 * Hyperreal: new method "transfer" that implements the transfer
  3368 principle of nonstandard analysis. With a subgoal that mentions
  3369 nonstandard types like "'a star", the command "apply transfer"
  3370 replaces it with an equivalent one that mentions only standard types.
  3371 To be successful, all free variables must have standard types; non-
  3372 standard variables must have explicit universal quantifiers.
  3373 
  3374 * Hyperreal: A theory of Taylor series.
  3375 
  3376 
  3377 *** HOLCF ***
  3378 
  3379 * Discontinued special version of 'constdefs' (which used to support
  3380 continuous functions) in favor of the general Pure one with full
  3381 type-inference.
  3382 
  3383 * New simplification procedure for solving continuity conditions; it
  3384 is much faster on terms with many nested lambda abstractions (cubic
  3385 instead of exponential time).
  3386 
  3387 * New syntax for domain package: selector names are now optional.
  3388 Parentheses should be omitted unless argument is lazy, for example:
  3389 
  3390   domain 'a stream = cons "'a" (lazy "'a stream")
  3391 
  3392 * New command 'fixrec' for defining recursive functions with pattern
  3393 matching; defining multiple functions with mutual recursion is also
  3394 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3395 sinr, or any data constructor defined by the domain package. The given
  3396 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3397 syntax and examples.
  3398 
  3399 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3400 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3401 but the proof obligation additionally includes an admissibility
  3402 requirement. The packages generate instances of class cpo or pcpo,
  3403 with continuity and strictness theorems for Rep and Abs.
  3404 
  3405 * HOLCF: Many theorems have been renamed according to a more standard naming
  3406 scheme (INCOMPATIBILITY):
  3407 
  3408   foo_inject:  "foo$x = foo$y ==> x = y"
  3409   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3410   foo_less:    "(foo$x << foo$y) = (x << y)"
  3411   foo_strict:  "foo$UU = UU"
  3412   foo_defined: "... ==> foo$x ~= UU"
  3413   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3414 
  3415 
  3416 *** ZF ***
  3417 
  3418 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3419 including the First Isomorphism Theorem (on quotienting by the kernel
  3420 of a homomorphism).
  3421 
  3422 * ZF/Simplifier: install second copy of type solver that actually
  3423 makes use of TC rules declared to Isar proof contexts (or locales);
  3424 the old version is still required for ML proof scripts.
  3425 
  3426 
  3427 *** Cube ***
  3428 
  3429 * Converted to Isar theory format; use locales instead of axiomatic
  3430 theories.
  3431 
  3432 
  3433 *** ML ***
  3434 
  3435 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3436 for ||>, ||>>, |>>,
  3437 
  3438 * Pure/library.ML no longer defines its own option datatype, but uses
  3439 that of the SML basis, which has constructors NONE and SOME instead of
  3440 None and Some, as well as exception Option.Option instead of OPTION.
  3441 The functions the, if_none, is_some, is_none have been adapted
  3442 accordingly, while Option.map replaces apsome.
  3443 
  3444 * Pure/library.ML: the exception LIST has been given up in favour of
  3445 the standard exceptions Empty and Subscript, as well as
  3446 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3447 superceded by the standard hd and tl functions etc.
  3448 
  3449 A number of basic list functions are no longer exported to the ML
  3450 toplevel, as they are variants of predefined functions.  The following
  3451 suggests how one can translate existing code:
  3452 
  3453     rev_append xs ys = List.revAppend (xs, ys)
  3454     nth_elem (i, xs) = List.nth (xs, i)
  3455     last_elem xs = List.last xs
  3456     flat xss = List.concat xss
  3457     seq fs = List.app fs
  3458     partition P xs = List.partition P xs
  3459     mapfilter f xs = List.mapPartial f xs
  3460 
  3461 * Pure/library.ML: several combinators for linear functional
  3462 transformations, notably reverse application and composition:
  3463 
  3464   x |> f                f #> g
  3465   (x, y) |-> f          f #-> g
  3466 
  3467 * Pure/library.ML: introduced/changed precedence of infix operators:
  3468 
  3469   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3470   infix 2 ?;
  3471   infix 3 o oo ooo oooo;
  3472   infix 4 ~~ upto downto;
  3473 
  3474 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3475 infix operators.
  3476 
  3477 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3478 fold_map support linear functional transformations and nesting.  For
  3479 example:
  3480 
  3481   fold f [x1, ..., xN] y =
  3482     y |> f x1 |> ... |> f xN
  3483 
  3484   (fold o fold) f [xs1, ..., xsN] y =
  3485     y |> fold f xs1 |> ... |> fold f xsN
  3486 
  3487   fold f [x1, ..., xN] =
  3488     f x1 #> ... #> f xN
  3489 
  3490   (fold o fold) f [xs1, ..., xsN] =
  3491     fold f xs1 #> ... #> fold f xsN
  3492 
  3493 * Pure/library.ML: the following selectors on type 'a option are
  3494 available:
  3495 
  3496   the:               'a option -> 'a  (*partial*)
  3497   these:             'a option -> 'a  where 'a = 'b list
  3498   the_default: 'a -> 'a option -> 'a
  3499   the_list:          'a option -> 'a list
  3500 
  3501 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3502 basic operations for association lists, following natural argument
  3503 order; moreover the explicit equality predicate passed here avoids
  3504 potentially expensive polymorphic runtime equality checks.
  3505 The old functions may be expressed as follows:
  3506 
  3507   assoc = uncurry (AList.lookup (op =))
  3508   assocs = these oo AList.lookup (op =)
  3509   overwrite = uncurry (AList.update (op =)) o swap
  3510 
  3511 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3512 
  3513   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3514   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3515 
  3516 replacing make_keylist and keyfilter (occassionally used)
  3517 Naive rewrites:
  3518 
  3519   make_keylist = AList.make
  3520   keyfilter = AList.find (op =)
  3521 
  3522 * eq_fst and eq_snd now take explicit equality parameter, thus
  3523   avoiding eqtypes. Naive rewrites:
  3524 
  3525     eq_fst = eq_fst (op =)
  3526     eq_snd = eq_snd (op =)
  3527 
  3528 * Removed deprecated apl and apr (rarely used).
  3529   Naive rewrites:
  3530 
  3531     apl (n, op) =>>= curry op n
  3532     apr (op, m) =>>= fn n => op (n, m)
  3533 
  3534 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3535 provides a reasonably efficient light-weight implementation of sets as
  3536 lists.
  3537 
  3538 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3539 few new operations; existing lookup and update are now curried to
  3540 follow natural argument order (for use with fold etc.);
  3541 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3542 
  3543 * Pure/General: output via the Isabelle channels of
  3544 writeln/warning/error etc. is now passed through Output.output, with a
  3545 hook for arbitrary transformations depending on the print_mode
  3546 (cf. Output.add_mode -- the first active mode that provides a output
  3547 function wins).  Already formatted output may be embedded into further
  3548 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3549 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3550 accommodate easy composition of diagnostic messages etc.  Programmers
  3551 rarely need to care about Output.output or Output.raw at all, with
  3552 some notable exceptions: Output.output is required when bypassing the
  3553 standard channels (writeln etc.), or in token translations to produce
  3554 properly formatted results; Output.raw is required when capturing
  3555 already output material that will eventually be presented to the user
  3556 a second time.  For the default print mode, both Output.output and
  3557 Output.raw have no effect.
  3558 
  3559 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3560 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3561 cumulative results are displayed at the end of a batch session.
  3562 
  3563 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3564 replaced by File.platform_path and File.shell_path (with appropriate
  3565 hooks).  This provides a clean interface for unusual systems where the
  3566 internal and external process view of file names are different.
  3567 
  3568 * Pure: more efficient orders for basic syntactic entities: added
  3569 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3570 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3571 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3572 orders now -- potential INCOMPATIBILITY for code that depends on a
  3573 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3574 Library.sort_strings on result).
  3575 
  3576 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3577 fold_types traverse types/terms from left to right, observing natural
  3578 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3579 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3580 
  3581 * Pure: name spaces have been refined, with significant changes of the
  3582 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3583 to extern(_table).  The plain name entry path is superceded by a
  3584 general 'naming' context, which also includes the 'policy' to produce
  3585 a fully qualified name and external accesses of a fully qualified
  3586 name; NameSpace.extend is superceded by context dependent
  3587 Sign.declare_name.  Several theory and proof context operations modify
  3588 the naming context.  Especially note Theory.restore_naming and
  3589 ProofContext.restore_naming to get back to a sane state; note that
  3590 Theory.add_path is no longer sufficient to recover from
  3591 Theory.absolute_path in particular.
  3592 
  3593 * Pure: new flags short_names (default false) and unique_names
  3594 (default true) for controlling output of qualified names.  If
  3595 short_names is set, names are printed unqualified.  If unique_names is
  3596 reset, the name prefix is reduced to the minimum required to achieve
  3597 the original result when interning again, even if there is an overlap
  3598 with earlier declarations.
  3599 
  3600 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3601 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3602 (useful for printing error messages).  INCOMPATIBILITY.
  3603 
  3604 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3605 Theory.theory are now identified, referring to the universal
  3606 Context.theory (see Pure/context.ML).  Actual signature and theory
  3607 content is managed as theory data.  The old code and interfaces were
  3608 spread over many files and structures; the new arrangement introduces
  3609 considerable INCOMPATIBILITY to gain more clarity:
  3610 
  3611   Context -- theory management operations (name, identity, inclusion,
  3612     parents, ancestors, merge, etc.), plus generic theory data;
  3613 
  3614   Sign -- logical signature and syntax operations (declaring consts,
  3615     types, etc.), plus certify/read for common entities;
  3616 
  3617   Theory -- logical theory operations (stating axioms, definitions,
  3618     oracles), plus a copy of logical signature operations (consts,
  3619     types, etc.); also a few basic management operations (Theory.copy,
  3620     Theory.merge, etc.)
  3621 
  3622 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3623 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3624 for convenience -- they merely return the theory.
  3625 
  3626 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3627 
  3628 * Pure: the Isar proof context type is already defined early in Pure
  3629 as Context.proof (note that ProofContext.context and Proof.context are
  3630 aliases, where the latter is the preferred name).  This enables other
  3631 Isabelle components to refer to that type even before Isar is present.
  3632 
  3633 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3634 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3635 any of these kinds.  For example, Sign.intern typeK is now
  3636 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3637 Theory.hide_types.  Also note that former
  3638 Theory.hide_classes/types/consts are now
  3639 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3640 internalize their arguments!  INCOMPATIBILITY.
  3641 
  3642 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3643 datatype thmref (with constructors Name and NameSelection) instead of
  3644 plain string -- INCOMPATIBILITY;
  3645 
  3646 * Pure: cases produced by proof methods specify options, where NONE
  3647 means to remove case bindings -- INCOMPATIBILITY in
  3648 (RAW_)METHOD_CASES.
  3649 
  3650 * Pure: the following operations retrieve axioms or theorems from a
  3651 theory node or theory hierarchy, respectively:
  3652 
  3653   Theory.axioms_of: theory -> (string * term) list
  3654   Theory.all_axioms_of: theory -> (string * term) list
  3655   PureThy.thms_of: theory -> (string * thm) list
  3656   PureThy.all_thms_of: theory -> (string * thm) list
  3657 
  3658 * Pure: print_tac now outputs the goal through the trace channel.
  3659 
  3660 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3661 Reference Toplevel.debug (default false) controls detailed printing
  3662 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3663 controls execution profiling -- set to 1 for time and 2 for space
  3664 (both increase the runtime).
  3665 
  3666 * Isar session: The initial use of ROOT.ML is now always timed,
  3667 i.e. the log will show the actual process times, in contrast to the
  3668 elapsed wall-clock time that the outer shell wrapper produces.
  3669 
  3670 * Simplifier: improved handling of bound variables (nameless
  3671 representation, avoid allocating new strings).  Simprocs that invoke
  3672 the Simplifier recursively should use Simplifier.inherit_bounds to
  3673 avoid local name clashes.  Failure to do so produces warnings
  3674 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3675 for further details.
  3676 
  3677 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3678 bindings for all theorems stored within a given theory; this may help
  3679 in porting non-Isar theories to Isar ones, while keeping ML proof
  3680 scripts for the time being.
  3681 
  3682 * ML operator HTML.with_charset specifies the charset begin used for
  3683 generated HTML files.  For example:
  3684 
  3685   HTML.with_charset "utf-8" use_thy "Hebrew";
  3686   HTML.with_charset "utf-8" use_thy "Chinese";
  3687 
  3688 
  3689 *** System ***
  3690 
  3691 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3692 isabelle, isatool etc.).
  3693 
  3694 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3695 isatool doc, isatool mkdir, display_drafts etc.).
  3696 
  3697 * isatool usedir: option -f allows specification of the ML file to be
  3698 used by Isabelle; default is ROOT.ML.
  3699 
  3700 * New isatool version outputs the version identifier of the Isabelle
  3701 distribution being used.
  3702 
  3703 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3704 (containing Boolean satisfiability problems) into Isabelle/HOL
  3705 theories.
  3706 
  3707 
  3708 
  3709 New in Isabelle2004 (April 2004)
  3710 --------------------------------
  3711 
  3712 *** General ***
  3713 
  3714 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3715   Replaces linorder.ML.
  3716 
  3717 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3718   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3719   (\<a>...\<z>), are now considered normal letters, and can therefore
  3720   be used anywhere where an ASCII letter (a...zA...Z) has until
  3721   now. COMPATIBILITY: This obviously changes the parsing of some
  3722   terms, especially where a symbol has been used as a binder, say
  3723   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3724   as an identifier.  Fix it by inserting a space around former
  3725   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3726   existing theory and ML files.
  3727 
  3728 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3729 
  3730 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3731   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3732   a normal (but invisible) letter. For multiple letter subscripts repeat
  3733   \<^isub> like this: x\<^isub>1\<^isub>2.
  3734 
  3735 * Pure: There are now sub-/superscripts that can span more than one
  3736   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3737   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3738   superscript. The new control characters are not identifier parts.
  3739 
  3740 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3741   content of "..." to the latex file instead of \isacntrl... . The "..."
  3742   may consist of any printable characters excluding the end bracket >.
  3743 
  3744 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3745   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3746   declare constants "final", which prevents their being given a definition
  3747   later.  It is useful for constants whose behaviour is fixed axiomatically
  3748   rather than definitionally, such as the meta-logic connectives.
  3749 
  3750 * Pure: 'instance' now handles general arities with general sorts
  3751   (i.e. intersections of classes),
  3752 
  3753 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3754   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3755   It can be changed to alter the colors/layout of generated pages.
  3756 
  3757 
  3758 *** Isar ***
  3759 
  3760 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3761   cut_tac, subgoal_tac and thin_tac:
  3762   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3763     locales are no longer forced to write Isar proof scripts.
  3764     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3765     emulations.
  3766   - INCOMPATIBILITY: names of variables to be instantiated may no
  3767     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3768     This is consistent with the instantiation attribute "where".
  3769 
  3770 * Attributes "where" and "of":
  3771   - Now take type variables of instantiated theorem into account when reading
  3772     the instantiation string.  This fixes a bug that caused instantiated
  3773     theorems to have too special types in some circumstances.
  3774   - "where" permits explicit instantiations of type variables.
  3775 
  3776 * Calculation commands "moreover" and "also" no longer interfere with
  3777   current facts ("this"), admitting arbitrary combinations with "then"
  3778   and derived forms.
  3779 
  3780 * Locales:
  3781   - Goal statements involving the context element "includes" no longer
  3782     generate theorems with internal delta predicates (those ending on
  3783     "_axioms") in the premise.
  3784     Resolve particular premise with <locale>.intro to obtain old form.
  3785   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3786     specification and "includes" elements in goal statement.
  3787   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3788     [intro?] and [elim?] (respectively) by default.
  3789   - Experimental command for instantiation of locales in proof contexts:
  3790         instantiate <label>[<attrs>]: <loc>
  3791     Instantiates locale <loc> and adds all its theorems to the current context
  3792     taking into account their attributes.  Label and attrs are optional
  3793     modifiers, like in theorem declarations.  If present, names of
  3794     instantiated theorems are qualified with <label>, and the attributes
  3795     <attrs> are applied after any attributes these theorems might have already.
  3796       If the locale has assumptions, a chained fact of the form
  3797     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3798     are derived.  The command does not support old-style locales declared
  3799     with "locale (open)".
  3800       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3801 
  3802 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3803   (Isar) contexts.
  3804 
  3805 
  3806 *** HOL ***
  3807 
  3808 * Proof import: new image HOL4 contains the imported library from
  3809   the HOL4 system with about 2500 theorems. It is imported by
  3810   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3811   can be used like any other Isabelle image.  See
  3812   HOL/Import/HOL/README for more information.
  3813 
  3814 * Simplifier:
  3815   - Much improved handling of linear and partial orders.
  3816     Reasoners for linear and partial orders are set up for type classes
  3817     "linorder" and "order" respectively, and are added to the default simpset
  3818     as solvers.  This means that the simplifier can build transitivity chains
  3819     to solve goals from the assumptions.
  3820   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3821     of blast or auto after simplification become unnecessary because the goal
  3822     is solved by simplification already.
  3823 
  3824 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3825     all proved in axiomatic type classes for semirings, rings and fields.
  3826 
  3827 * Numerics:
  3828   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3829     now formalized using the Ring_and_Field theory mentioned above.
  3830   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3831     than before, because now they are set up once in a generic manner.
  3832   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3833     Look for the general versions in Ring_and_Field (and Power if they concern
  3834     exponentiation).
  3835 
  3836 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3837 
  3838 * Records:
  3839   - Record types are now by default printed with their type abbreviation
  3840     instead of the list of all field types. This can be configured via
  3841     the reference "print_record_type_abbr".
  3842   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3843     (not enabled by default).
  3844   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3845     EX x. x = sel r to True (not enabled by default).
  3846   - Tactic "record_split_simp_tac" to split and simplify records added.
  3847 
  3848 * 'specification' command added, allowing for definition by
  3849   specification.  There is also an 'ax_specification' command that
  3850   introduces the new constants axiomatically.
  3851 
  3852 * arith(_tac) is now able to generate counterexamples for reals as well.
  3853 
  3854 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3855 
  3856 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3857   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3858 
  3859 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3860   matrix theory to linear programming.
  3861 
  3862 * Unions and Intersections:
  3863   The latex output syntax of UN and INT has been changed
  3864   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3865   i.e. the index formulae has become a subscript.
  3866   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3867 
  3868 * Unions and Intersections over Intervals:
  3869   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3870   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3871   like in normal math, and corresponding versions for < and for intersection.
  3872 
  3873 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3874   lexicographic dictonary ordering has been added as "lexord".
  3875 
  3876 * ML: the legacy theory structures Int and List have been removed. They had
  3877   conflicted with ML Basis Library structures having the same names.
  3878 
  3879 * 'refute' command added to search for (finite) countermodels.  Only works
  3880   for a fragment of HOL.  The installation of an external SAT solver is
  3881   highly recommended.  See "HOL/Refute.thy" for details.
  3882 
  3883 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3884   formulae under an assignment of free variables to random values.
  3885   In contrast to 'refute', it can deal with inductive datatypes,
  3886   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3887   for examples.
  3888 
  3889 
  3890 *** HOLCF ***
  3891 
  3892 * Streams now come with concatenation and are part of the HOLCF image
  3893 
  3894 
  3895 
  3896 New in Isabelle2003 (May 2003)
  3897 ------------------------------
  3898 
  3899 *** General ***
  3900 
  3901 * Provers/simplifier:
  3902 
  3903   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3904     Assumptions are now subject to complete mutual simplification,
  3905     not just from left to right. The simplifier now preserves
  3906     the order of assumptions.
  3907 
  3908     Potential INCOMPATIBILITY:
  3909 
  3910     -- simp sometimes diverges where the old version did
  3911        not, e.g. invoking simp on the goal
  3912 
  3913         [| P (f x); y = x; f x = f y |] ==> Q
  3914 
  3915        now gives rise to the infinite reduction sequence
  3916 
  3917         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3918 
  3919        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3920        kind of problem.
  3921 
  3922     -- Tactics combining classical reasoner and simplification (such as auto)
  3923        are also affected by this change, because many of them rely on
  3924        simp. They may sometimes diverge as well or yield a different numbers
  3925        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3926        in case of problems. Sometimes subsequent calls to the classical
  3927        reasoner will fail because a preceeding call to the simplifier too
  3928        eagerly simplified the goal, e.g. deleted redundant premises.
  3929 
  3930   - The simplifier trace now shows the names of the applied rewrite rules
  3931 
  3932   - You can limit the number of recursive invocations of the simplifier
  3933     during conditional rewriting (where the simplifie tries to solve the
  3934     conditions before applying the rewrite rule):
  3935     ML "simp_depth_limit := n"
  3936     where n is an integer. Thus you can force termination where previously
  3937     the simplifier would diverge.
  3938 
  3939   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3940 
  3941   - No longer aborts on failed congruence proof.  Instead, the
  3942     congruence is ignored.
  3943 
  3944 * Pure: New generic framework for extracting programs from constructive
  3945   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3946   as HOL/Extraction for some case studies.
  3947 
  3948 * Pure: The main goal of the proof state is no longer shown by default, only
  3949 the subgoals. This behaviour is controlled by a new flag.
  3950    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3951 (ML: Proof.show_main_goal).
  3952 
  3953 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3954 rules whose conclusion matches subgoal 1:
  3955       PG menu: Isabelle/Isar -> Show me -> matching rules
  3956 The rules are ordered by how closely they match the subgoal.
  3957 In particular, rules that solve a subgoal outright are displayed first
  3958 (or rather last, the way they are printed).
  3959 (ML: ProofGeneral.print_intros())
  3960 
  3961 * Pure: New flag trace_unify_fail causes unification to print
  3962 diagnostic information (PG: in trace buffer) when it fails. This is
  3963 useful for figuring out why single step proofs like rule, erule or
  3964 assumption failed.
  3965 
  3966 * Pure: Locale specifications now produce predicate definitions
  3967 according to the body of text (covering assumptions modulo local
  3968 definitions); predicate "loc_axioms" covers newly introduced text,
  3969 while "loc" is cumulative wrt. all included locale expressions; the
  3970 latter view is presented only on export into the global theory
  3971 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3972 on the old view without predicates;
  3973 
  3974 * Pure: predefined locales "var" and "struct" are useful for sharing
  3975 parameters (as in CASL, for example); just specify something like
  3976 ``var x + var y + struct M'' as import;
  3977 
  3978 * Pure: improved thms_containing: proper indexing of facts instead of
  3979 raw theorems; check validity of results wrt. current name space;
  3980 include local facts of proof configuration (also covers active
  3981 locales), cover fixed variables in index; may use "_" in term
  3982 specification; an optional limit for the number of printed facts may
  3983 be given (the default is 40);
  3984 
  3985 * Pure: disallow duplicate fact bindings within new-style theory files
  3986 (batch-mode only);
  3987 
  3988 * Provers: improved induct method: assumptions introduced by case
  3989 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3990 the goal statement); "foo" still refers to all facts collectively;
  3991 
  3992 * Provers: the function blast.overloaded has been removed: all constants
  3993 are regarded as potentially overloaded, which improves robustness in exchange
  3994 for slight decrease in efficiency;
  3995 
  3996 * Provers/linorder: New generic prover for transitivity reasoning over
  3997 linear orders.  Note: this prover is not efficient!
  3998 
  3999 * Isar: preview of problems to finish 'show' now produce an error
  4000 rather than just a warning (in interactive mode);
  4001 
  4002 
  4003 *** HOL ***
  4004 
  4005 * arith(_tac)
  4006 
  4007  - Produces a counter example if it cannot prove a goal.
  4008    Note that the counter example may be spurious if the goal is not a formula
  4009    of quantifier-free linear arithmetic.
  4010    In ProofGeneral the counter example appears in the trace buffer.
  4011 
  4012  - Knows about div k and mod k where k is a numeral of type nat or int.
  4013 
  4014  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  4015    linear arithmetic fails. This takes account of quantifiers and divisibility.
  4016    Presburger arithmetic can also be called explicitly via presburger(_tac).
  4017 
  4018 * simp's arithmetic capabilities have been enhanced a bit: it now
  4019 takes ~= in premises into account (by performing a case split);
  4020 
  4021 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  4022 are distributed over a sum of terms;
  4023 
  4024 * New tactic "trans_tac" and method "trans" instantiate
  4025 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  4026 "<=", "<" and "=").
  4027 
  4028 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  4029 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  4030 
  4031 * 'typedef' command has new option "open" to suppress the set
  4032 definition;
  4033 
  4034 * functions Min and Max on finite sets have been introduced (theory
  4035 Finite_Set);
  4036 
  4037 * attribute [symmetric] now works for relations as well; it turns
  4038 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4039 
  4040 * induct over a !!-quantified statement (say !!x1..xn):
  4041   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4042 
  4043 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4044 %x. None. Warning: empty_def now refers to the previously hidden definition
  4045 of the empty set.
  4046 
  4047 * Algebra: formalization of classical algebra.  Intended as base for
  4048 any algebraic development in Isabelle.  Currently covers group theory
  4049 (up to Sylow's theorem) and ring theory (Universal Property of
  4050 Univariate Polynomials).  Contributions welcome;
  4051 
  4052 * GroupTheory: deleted, since its material has been moved to Algebra;
  4053 
  4054 * Complex: new directory of the complex numbers with numeric constants,
  4055 nonstandard complex numbers, and some complex analysis, standard and
  4056 nonstandard (Jacques Fleuriot);
  4057 
  4058 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4059 
  4060 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4061 Fleuriot);
  4062 
  4063 * Real/HahnBanach: updated and adapted to locales;
  4064 
  4065 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4066 Gray and Kramer);
  4067 
  4068 * UNITY: added the Meier-Sanders theory of progress sets;
  4069 
  4070 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4071 as abstract algorithms, instantiated to the JVM;
  4072 
  4073 * Bali: Java source language formalization. Type system, operational
  4074 semantics, axiomatic semantics. Supported language features:
  4075 classes, interfaces, objects,virtual methods, static methods,
  4076 static/instance fields, arrays, access modifiers, definite
  4077 assignment, exceptions.
  4078 
  4079 
  4080 *** ZF ***
  4081 
  4082 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4083 universe, etc.);
  4084 
  4085 * Main ZF: virtually all theories converted to new-style format;
  4086 
  4087 
  4088 *** ML ***
  4089 
  4090 * Pure: Tactic.prove provides sane interface for internal proofs;
  4091 omits the infamous "standard" operation, so this is more appropriate
  4092 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4093 
  4094 * Pure: improved error reporting of simprocs;
  4095 
  4096 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4097 up simprocs;
  4098 
  4099 
  4100 *** Document preparation ***
  4101 
  4102 * uses \par instead of \\ for line breaks in theory text. This may
  4103 shift some page breaks in large documents. To get the old behaviour
  4104 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4105 
  4106 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4107 other packages
  4108 
  4109 * \<euro> now needs package babel/greek instead of marvosym (which
  4110 broke \Rightarrow)
  4111 
  4112 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4113 textcomp package)
  4114 
  4115 
  4116 
  4117 New in Isabelle2002 (March 2002)
  4118 --------------------------------
  4119 
  4120 *** Document preparation ***
  4121 
  4122 * greatly simplified document preparation setup, including more
  4123 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4124 instructive isatool mkdir; users should basically be able to get
  4125 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4126 users may run a separate document processing stage manually like this:
  4127 "isatool usedir -D output HOL Test && isatool document Test/output";
  4128 
  4129 * theory dependency graph may now be incorporated into documents;
  4130 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4131 with \includegraphics of LaTeX;
  4132 
  4133 * proper spacing of consecutive markup elements, especially text
  4134 blocks after section headings;
  4135 
  4136 * support bold style (for single symbols only), input syntax is like
  4137 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4138 
  4139 * \<bullet> is now output as bold \cdot by default, which looks much
  4140 better in printed text;
  4141 
  4142 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4143 note that these symbols are currently unavailable in Proof General /
  4144 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4145 
  4146 * isatool latex no longer depends on changed TEXINPUTS, instead
  4147 isatool document copies the Isabelle style files to the target
  4148 location;
  4149 
  4150 
  4151 *** Isar ***
  4152 
  4153 * Pure/Provers: improved proof by cases and induction;
  4154   - 'case' command admits impromptu naming of parameters (such as
  4155     "case (Suc n)");
  4156   - 'induct' method divinates rule instantiation from the inductive
  4157     claim; no longer requires excessive ?P bindings for proper
  4158     instantiation of cases;
  4159   - 'induct' method properly enumerates all possibilities of set/type
  4160     rules; as a consequence facts may be also passed through *type*
  4161     rules without further ado;
  4162   - 'induct' method now derives symbolic cases from the *rulified*
  4163     rule (before it used to rulify cases stemming from the internal
  4164     atomized version); this means that the context of a non-atomic
  4165     statement becomes is included in the hypothesis, avoiding the
  4166     slightly cumbersome show "PROP ?case" form;
  4167   - 'induct' may now use elim-style induction rules without chaining
  4168     facts, using ``missing'' premises from the goal state; this allows
  4169     rules stemming from inductive sets to be applied in unstructured
  4170     scripts, while still benefitting from proper handling of non-atomic
  4171     statements; NB: major inductive premises need to be put first, all
  4172     the rest of the goal is passed through the induction;
  4173   - 'induct' proper support for mutual induction involving non-atomic
  4174     rule statements (uses the new concept of simultaneous goals, see
  4175     below);
  4176   - append all possible rule selections, but only use the first
  4177     success (no backtracking);
  4178   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4179   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4180   - added 'print_induct_rules' (covered by help item in recent Proof
  4181     General versions);
  4182   - moved induct/cases attributes to Pure, methods to Provers;
  4183   - generic method setup instantiated for FOL and HOL;
  4184 
  4185 * Pure: support multiple simultaneous goal statements, for example
  4186 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4187 meta-level mechanism, this acts as if several individual goals had
  4188 been stated separately; in particular common proof methods need to be
  4189 repeated in order to cover all claims; note that a single elimination
  4190 step is *not* sufficient to establish the two conjunctions, so this
  4191 fails:
  4192 
  4193   assume "A & B" then have A and B ..   (*".." fails*)
  4194 
  4195 better use "obtain" in situations as above; alternative refer to
  4196 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4197 
  4198 * Pure: proper integration with ``locales''; unlike the original
  4199 version by Florian Kammller, Isar locales package high-level proof
  4200 contexts rather than raw logical ones (e.g. we admit to include
  4201 attributes everywhere); operations on locales include merge and
  4202 rename; support for implicit arguments (``structures''); simultaneous
  4203 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4204 some examples;
  4205 
  4206 * Pure: the following commands have been ``localized'', supporting a
  4207 target locale specification "(in name)": 'lemma', 'theorem',
  4208 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4209 stored both within the locale and at the theory level (exported and
  4210 qualified by the locale name);
  4211 
  4212 * Pure: theory goals may now be specified in ``long'' form, with
  4213 ad-hoc contexts consisting of arbitrary locale elements. for example
  4214 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4215 definitions may be given, too); the result is a meta-level rule with
  4216 the context elements being discharged in the obvious way;
  4217 
  4218 * Pure: new proof command 'using' allows to augment currently used
  4219 facts after a goal statement ('using' is syntactically analogous to
  4220 'apply', but acts on the goal's facts only); this allows chained facts
  4221 to be separated into parts given before and after a claim, as in
  4222 ``from a and b have C using d and e <proof>'';
  4223 
  4224 * Pure: renamed "antecedent" case to "rule_context";
  4225 
  4226 * Pure: new 'judgment' command records explicit information about the
  4227 object-logic embedding (used by several tools internally); no longer
  4228 use hard-wired "Trueprop";
  4229 
  4230 * Pure: added 'corollary' command;
  4231 
  4232 * Pure: fixed 'token_translation' command;
  4233 
  4234 * Pure: removed obsolete 'exported' attribute;
  4235 
  4236 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4237 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4238 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4239 
  4240 * Pure: method 'atomize' presents local goal premises as object-level
  4241 statements (atomic meta-level propositions); setup controlled via
  4242 rewrite rules declarations of 'atomize' attribute; example
  4243 application: 'induct' method with proper rule statements in improper
  4244 proof *scripts*;
  4245 
  4246 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4247 now consider the syntactic context of assumptions, giving a better
  4248 chance to get type-inference of the arguments right (this is
  4249 especially important for locales);
  4250 
  4251 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4252 mode;
  4253 
  4254 * Pure/obtain: the formal conclusion "thesis", being marked as
  4255 ``internal'', may no longer be reference directly in the text;
  4256 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4257 situations;
  4258 
  4259 * Pure: generic 'sym' attribute which declares a rule both as pure
  4260 'elim?' and for the 'symmetric' operation;
  4261 
  4262 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4263 text; the fixed correlation with particular command syntax has been
  4264 discontinued;
  4265 
  4266 * Pure: new method 'rules' is particularly well-suited for proof
  4267 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4268 but often produces more compact proof terms with less detours;
  4269 
  4270 * Pure/Provers/classical: simplified integration with pure rule
  4271 attributes and methods; the classical "intro?/elim?/dest?"
  4272 declarations coincide with the pure ones; the "rule" method no longer
  4273 includes classically swapped intros; "intro" and "elim" methods no
  4274 longer pick rules from the context; also got rid of ML declarations
  4275 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4276 INCOMPATIBILITY;
  4277 
  4278 * Provers/classical: attribute 'swapped' produces classical inversions
  4279 of introduction rules;
  4280 
  4281 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4282 rules instead of full simplifier context; 'iff' attribute handles
  4283 conditional rules;
  4284 
  4285 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4286 
  4287 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4288 "(permissive)" option to recover old behavior;
  4289 
  4290 * HOL: 'inductive' no longer features separate (collective) attributes
  4291 for 'intros' (was found too confusing);
  4292 
  4293 * HOL: properly declared induction rules less_induct and
  4294 wf_induct_rule;
  4295 
  4296 
  4297 *** HOL ***
  4298 
  4299 * HOL: moved over to sane numeral syntax; the new policy is as
  4300 follows:
  4301 
  4302   - 0 and 1 are polymorphic constants, which are defined on any
  4303   numeric type (nat, int, real etc.);
  4304 
  4305   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4306   binary representation internally;
  4307 
  4308   - type nat has special constructor Suc, and generally prefers Suc 0
  4309   over 1::nat and Suc (Suc 0) over 2::nat;
  4310 
  4311 This change may cause significant problems of INCOMPATIBILITY; here
  4312 are some hints on converting existing sources:
  4313 
  4314   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4315   entities, so expressions involving "-" (unary or binary minus) need
  4316   to be spaced properly;
  4317 
  4318   - existing occurrences of "1" may need to be constraint "1::nat" or
  4319   even replaced by Suc 0; similar for old "2";
  4320 
  4321   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4322 
  4323   - remove all special provisions on numerals in proofs;
  4324 
  4325 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4326 representation (depends on bin_arith_simps in the default context);
  4327 
  4328 * HOL: symbolic syntax for x^2 (numeral 2);
  4329 
  4330 * HOL: the class of all HOL types is now called "type" rather than
  4331 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4332 in axclass/classes, instance/arities, and (usually rare) occurrences
  4333 in typings (of consts etc.); internally the class is called
  4334 "HOL.type", ML programs should refer to HOLogic.typeS;
  4335 
  4336 * HOL/record package improvements:
  4337   - new derived operations "fields" to build a partial record section,
  4338     "extend" to promote a fixed record to a record scheme, and
  4339     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4340     declared as simp by default;
  4341   - shared operations ("more", "fields", etc.) now need to be always
  4342     qualified) --- potential INCOMPATIBILITY;
  4343   - removed "make_scheme" operations (use "make" with "extend") --
  4344     INCOMPATIBILITY;
  4345   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4346   - provides cases/induct rules for use with corresponding Isar
  4347     methods (for concrete records, record schemes, concrete more
  4348     parts, and schematic more parts -- in that order);
  4349   - internal definitions directly based on a light-weight abstract
  4350     theory of product types over typedef rather than datatype;
  4351 
  4352 * HOL: generic code generator for generating executable ML code from
  4353 specifications; specific support for HOL constructs such as inductive
  4354 datatypes and sets, as well as recursive functions; can be invoked
  4355 via 'generate_code' theory section;
  4356 
  4357 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4358 
  4359 * HOL: consolidated and renamed several theories.  In particular:
  4360         Ord.thy has been absorbed into HOL.thy
  4361         String.thy has been absorbed into List.thy
  4362 
  4363 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4364 (beware of argument permutation!);
  4365 
  4366 * HOL: linorder_less_split superseded by linorder_cases;
  4367 
  4368 * HOL/List: "nodups" renamed to "distinct";
  4369 
  4370 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4371 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4372   - Ex_def has changed, now need to use some_eq_ex
  4373 
  4374 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4375 in this (rare) case use:
  4376 
  4377   delSWrapper "split_all_tac"
  4378   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4379 
  4380 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4381 MAY FAIL;
  4382 
  4383 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4384 Isabelle's type classes, ^ on functions and relations has too general
  4385 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4386 necessary to attach explicit type constraints;
  4387 
  4388 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4389 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4390 renamed accordingly (eg "compI" -> "rel_compI").
  4391 
  4392 * HOL: syntax translations now work properly with numerals and records
  4393 expressions;
  4394 
  4395 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4396 of "lam" -- INCOMPATIBILITY;
  4397 
  4398 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4399 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4400 renamed "Product_Type.unit";
  4401 
  4402 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4403 
  4404 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4405 the "cases" method);
  4406 
  4407 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4408 Florian Kammller);
  4409 
  4410 * HOL/IMP: updated and converted to new-style theory format; several
  4411 parts turned into readable document, with proper Isar proof texts and
  4412 some explanations (by Gerwin Klein);
  4413 
  4414 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4415 
  4416 * HOL-Hyperreal is now a logic image;
  4417 
  4418 
  4419 *** HOLCF ***
  4420 
  4421 * Isar: consts/constdefs supports mixfix syntax for continuous
  4422 operations;
  4423 
  4424 * Isar: domain package adapted to new-style theory format, e.g. see
  4425 HOLCF/ex/Dnat.thy;
  4426 
  4427 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4428 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4429 lift.induct_tac, always use UU instead of Undef;
  4430 
  4431 * HOLCF/IMP: updated and converted to new-style theory;
  4432 
  4433 
  4434 *** ZF ***
  4435 
  4436 * Isar: proper integration of logic-specific tools and packages,
  4437 including theory commands '(co)inductive', '(co)datatype',
  4438 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4439 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4440 
  4441 * theory Main no longer includes AC; for the Axiom of Choice, base
  4442 your theory on Main_ZFC;
  4443 
  4444 * the integer library now covers quotients and remainders, with many
  4445 laws relating division to addition, multiplication, etc.;
  4446 
  4447 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4448 typeless version of the formalism;
  4449 
  4450 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4451 format;
  4452 
  4453 * ZF/Induct: new directory for examples of inductive definitions,
  4454 including theory Multiset for multiset orderings; converted to
  4455 new-style theory format;
  4456 
  4457 * ZF: many new theorems about lists, ordinals, etc.;
  4458 
  4459 
  4460 *** General ***
  4461 
  4462 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4463 variable proof controls level of detail: 0 = no proofs (only oracle
  4464 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4465 also ref manual for further ML interfaces;
  4466 
  4467 * Pure/axclass: removed obsolete ML interface
  4468 goal_subclass/goal_arity;
  4469 
  4470 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4471 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4472 separate tokens, so expressions involving minus need to be spaced
  4473 properly;
  4474 
  4475 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4476 rather than "infixl" or "infixr";
  4477 
  4478 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4479 sort constraint specifications in type inference; e.g. "x::_::foo"
  4480 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4481 type variable);
  4482 
  4483 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4484 control output of nested => (types); the default behavior is
  4485 "type_brackets";
  4486 
  4487 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4488 tokens into AST constants;
  4489 
  4490 * Pure/syntax: prefer later declarations of translations and print
  4491 translation functions; potential INCOMPATIBILITY: need to reverse
  4492 multiple declarations for same syntax element constant;
  4493 
  4494 * Pure/show_hyps reset by default (in accordance to existing Isar
  4495 practice);
  4496 
  4497 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4498 addSafter;
  4499 
  4500 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4501 as well;
  4502 
  4503 * system: tested support for MacOS X; should be able to get Isabelle +
  4504 Proof General to work in a plain Terminal after installing Poly/ML
  4505 (e.g. from the Isabelle distribution area) and GNU bash alone
  4506 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4507 support requires further installations, e.g. from
  4508 http://fink.sourceforge.net/);
  4509 
  4510 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4511 
  4512 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4513 of 40 MB), cf. ML_OPTIONS;
  4514 
  4515 * system: Proof General keywords specification is now part of the
  4516 Isabelle distribution (see etc/isar-keywords.el);
  4517 
  4518 * system: support for persistent Proof General sessions (refrain from
  4519 outdating all loaded theories on startup); user may create writable
  4520 logic images like this: ``isabelle -q HOL Test'';
  4521 
  4522 * system: smart selection of Isabelle process versus Isabelle
  4523 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4524 run both "isabelle" and "Isabelle" even if file names are badly
  4525 damaged (executable inspects the case of the first letter of its own
  4526 name); added separate "isabelle-process" and "isabelle-interface";
  4527 
  4528 * system: refrain from any attempt at filtering input streams; no
  4529 longer support ``8bit'' encoding of old isabelle font, instead proper
  4530 iso-latin characters may now be used; the related isatools
  4531 "symbolinput" and "nonascii" have disappeared as well;
  4532 
  4533 * system: removed old "xterm" interface (the print modes "xterm" and
  4534 "xterm_color" are still available for direct use in a suitable
  4535 terminal);
  4536 
  4537 
  4538 
  4539 New in Isabelle99-2 (February 2001)
  4540 -----------------------------------
  4541 
  4542 *** Overview of INCOMPATIBILITIES ***
  4543 
  4544 * HOL: please note that theories in the Library and elsewhere often use the
  4545 new-style (Isar) format; to refer to their theorems in an ML script you must
  4546 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4547 
  4548 * HOL: inductive package no longer splits induction rule aggressively,
  4549 but only as far as specified by the introductions given; the old
  4550 format may be recovered via ML function complete_split_rule or attribute
  4551 'split_rule (complete)';
  4552 
  4553 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4554 gfp_Tarski to gfp_unfold;
  4555 
  4556 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4557 
  4558 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4559 relation); infix "^^" has been renamed "``"; infix "``" has been
  4560 renamed "`"; "univalent" has been renamed "single_valued";
  4561 
  4562 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4563 operation;
  4564 
  4565 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4566 
  4567 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4568 
  4569 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4570 consequence, it is no longer monotonic wrt. the local goal context
  4571 (which is now passed through the inductive cases);
  4572 
  4573 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4574 \<gg> to \<ggreater>;
  4575 
  4576 
  4577 *** Document preparation ***
  4578 
  4579 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4580 available: are "it" for near math-mode best-style output, "sl" for
  4581 slanted text style, and "tt" for plain type-writer; if no
  4582 \isabellestyle command is given, output is according to slanted
  4583 type-writer);
  4584 
  4585 * support sub/super scripts (for single symbols only), input syntax is
  4586 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4587 
  4588 * some more standard symbols; see Appendix A of the system manual for
  4589 the complete list of symbols defined in isabellesym.sty;
  4590 
  4591 * improved isabelle style files; more abstract symbol implementation
  4592 (should now use \isamath{...} and \isatext{...} in custom symbol
  4593 definitions);
  4594 
  4595 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4596 state; Note that presentation of goal states does not conform to
  4597 actual human-readable proof documents.  Please do not include goal
  4598 states into document output unless you really know what you are doing!
  4599 
  4600 * proper indentation of antiquoted output with proportional LaTeX
  4601 fonts;
  4602 
  4603 * no_document ML operator temporarily disables LaTeX document
  4604 generation;
  4605 
  4606 * isatool unsymbolize tunes sources for plain ASCII communication;
  4607 
  4608 
  4609 *** Isar ***
  4610 
  4611 * Pure: Isar now suffers initial goal statements to contain unbound
  4612 schematic variables (this does not conform to actual readable proof
  4613 documents, due to unpredictable outcome and non-compositional proof
  4614 checking); users who know what they are doing may use schematic goals
  4615 for Prolog-style synthesis of proven results;
  4616 
  4617 * Pure: assumption method (an implicit finishing) now handles actual
  4618 rules as well;
  4619 
  4620 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4621 initial goal, declare "that" only as Pure intro (only for single
  4622 steps); the "that" rule assumption may now be involved in implicit
  4623 finishing, thus ".." becomes a feasible for trivial obtains;
  4624 
  4625 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4626 instance proofs may be performed by "..";
  4627 
  4628 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4629 statements as well;
  4630 
  4631 * Pure: more robust selection of calculational rules;
  4632 
  4633 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4634 rule (as well as the assumption rule);
  4635 
  4636 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4637 lemmas, using the graph browser tool;
  4638 
  4639 * Pure: predict failure of "show" in interactive mode;
  4640 
  4641 * Pure: 'thms_containing' now takes actual terms as arguments;
  4642 
  4643 * HOL: improved method 'induct' --- now handles non-atomic goals
  4644 (potential INCOMPATIBILITY); tuned error handling;
  4645 
  4646 * HOL: cases and induct rules now provide explicit hints about the
  4647 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4648 any remaining facts are inserted into the goal verbatim;
  4649 
  4650 * HOL: local contexts (aka cases) may now contain term bindings as
  4651 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4652 the result to be shown in each case;
  4653 
  4654 * HOL: added 'recdef_tc' command;
  4655 
  4656 * isatool convert assists in eliminating legacy ML scripts;
  4657 
  4658 
  4659 *** HOL ***
  4660 
  4661 * HOL/Library: a collection of generic theories to be used together
  4662 with main HOL; the theory loader path already includes this directory
  4663 by default; the following existing theories have been moved here:
  4664 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4665 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4666 
  4667 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4668 modelling and verification task performed in Isabelle/HOL +
  4669 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4670 
  4671 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4672 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4673 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4674 'domain', this makes the theory consistent with mathematical
  4675 literature;
  4676 
  4677 * HOL basics: added overloaded operations "inverse" and "divide"
  4678 (infix "/"), syntax for generic "abs" operation, generic summation
  4679 operator \<Sum>;
  4680 
  4681 * HOL/typedef: simplified package, provide more useful rules (see also
  4682 HOL/subset.thy);
  4683 
  4684 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4685 now expressed as a proper nested rule (old-style tactic scripts may
  4686 require atomize_strip_tac to cope with non-atomic premises);
  4687 
  4688 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4689 to "split_conv" (old name still available for compatibility);
  4690 
  4691 * HOL: improved concrete syntax for strings (e.g. allows translation
  4692 rules with string literals);
  4693 
  4694 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4695  and Fleuriot's mechanization of analysis, including the transcendental
  4696  functions for the reals;
  4697 
  4698 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4699 
  4700 
  4701 *** CTT ***
  4702 
  4703 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4704 "lam" is displayed as TWO lambda-symbols
  4705 
  4706 * CTT: theory Main now available, containing everything (that is, Bool
  4707 and Arith);
  4708 
  4709 
  4710 *** General ***
  4711 
  4712 * Pure: the Simplifier has been implemented properly as a derived rule
  4713 outside of the actual kernel (at last!); the overall performance
  4714 penalty in practical applications is about 50%, while reliability of
  4715 the Isabelle inference kernel has been greatly improved;
  4716 
  4717 * print modes "brackets" and "no_brackets" control output of nested =>
  4718 (types) and ==> (props); the default behaviour is "brackets";
  4719 
  4720 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4721 as assumptions as well;
  4722 
  4723 * system: support Poly/ML 4.0;
  4724 
  4725 * system: isatool install handles KDE version 1 or 2;
  4726 
  4727 
  4728 
  4729 New in Isabelle99-1 (October 2000)
  4730 ----------------------------------
  4731 
  4732 *** Overview of INCOMPATIBILITIES ***
  4733 
  4734 * HOL: simplification of natural numbers is much changed; to partly
  4735 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4736 issue the following ML commands:
  4737 
  4738   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4739   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4740 
  4741 * HOL: simplification no longer dives into case-expressions; this is
  4742 controlled by "t.weak_case_cong" for each datatype t;
  4743 
  4744 * HOL: nat_less_induct renamed to less_induct;
  4745 
  4746 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4747 fixsome to patch .thy and .ML sources automatically;
  4748 
  4749   select_equality  -> some_equality
  4750   select_eq_Ex     -> some_eq_ex
  4751   selectI2EX       -> someI2_ex
  4752   selectI2         -> someI2
  4753   selectI          -> someI
  4754   select1_equality -> some1_equality
  4755   Eps_sym_eq       -> some_sym_eq_trivial
  4756   Eps_eq           -> some_eq_trivial
  4757 
  4758 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4759 
  4760 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4761 instead);
  4762 
  4763 * HOL: the recursion equations generated by 'recdef' are now called
  4764 f.simps instead of f.rules;
  4765 
  4766 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4767 
  4768 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4769 sometimes be needed;
  4770 
  4771 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4772 
  4773 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4774 
  4775 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4776 product is now "<*>" instead of "Times"; the lexicographic product is
  4777 now "<*lex*>" instead of "**";
  4778 
  4779 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4780 of main HOL, but was unused); better use HOL's datatype package;
  4781 
  4782 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4783 the old syntax may be recovered as follows:
  4784 
  4785   syntax (symbols)
  4786     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4787       (infixl "\\<oplus>" 100)
  4788 
  4789 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4790 
  4791 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4792 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4793 internally;
  4794 
  4795 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4796 changed from A/r to A//r;
  4797 
  4798 * ZF: new treatment of arithmetic (nat & int) may break some old
  4799 proofs;
  4800 
  4801 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4802 rulify -> rule_format, elimify -> elim_format, ...);
  4803 
  4804 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4805 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4806 should have to change intro!! to intro? only); replaced "delrule" by
  4807 "rule del";
  4808 
  4809 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4810 
  4811 * Provers: strengthened force_tac by using new first_best_tac;
  4812 
  4813 * LaTeX document preparation: several changes of isabelle.sty (see
  4814 lib/texinputs);
  4815 
  4816 
  4817 *** Document preparation ***
  4818 
  4819 * formal comments (text blocks etc.) in new-style theories may now
  4820 contain antiquotations of thm/prop/term/typ/text to be presented
  4821 according to latex print mode; concrete syntax is like this:
  4822 @{term[show_types] "f(x) = a + x"};
  4823 
  4824 * isatool mkdir provides easy setup of Isabelle session directories,
  4825 including proper document sources;
  4826 
  4827 * generated LaTeX sources are now deleted after successful run
  4828 (isatool document -c); may retain a copy somewhere else via -D option
  4829 of isatool usedir;
  4830 
  4831 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4832 style files, achieving self-contained LaTeX sources and simplifying
  4833 LaTeX debugging;
  4834 
  4835 * old-style theories now produce (crude) LaTeX output as well;
  4836 
  4837 * browser info session directories are now self-contained (may be put
  4838 on WWW server seperately); improved graphs of nested sessions; removed
  4839 graph for 'all sessions';
  4840 
  4841 * several improvements in isabelle style files; \isabellestyle{it}
  4842 produces fake math mode output; \isamarkupheader is now \section by
  4843 default; see lib/texinputs/isabelle.sty etc.;
  4844 
  4845 
  4846 *** Isar ***
  4847 
  4848 * Isar/Pure: local results and corresponding term bindings are now
  4849 subject to Hindley-Milner polymorphism (similar to ML); this
  4850 accommodates incremental type-inference very nicely;
  4851 
  4852 * Isar/Pure: new derived language element 'obtain' supports
  4853 generalized existence reasoning;
  4854 
  4855 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4856 support accumulation of results, without applying any rules yet;
  4857 useful to collect intermediate results without explicit name
  4858 references, and for use with transitivity rules with more than 2
  4859 premises;
  4860 
  4861 * Isar/Pure: scalable support for case-analysis type proofs: new
  4862 'case' language element refers to local contexts symbolically, as
  4863 produced by certain proof methods; internally, case names are attached
  4864 to theorems as "tags";
  4865 
  4866 * Isar/Pure: theory command 'hide' removes declarations from
  4867 class/type/const name spaces;
  4868 
  4869 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4870 indicate potential overloading;
  4871 
  4872 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4873 
  4874 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4875 "{a,b,c}" instead of {a,b,c};
  4876 
  4877 * Isar/Pure now provides its own version of intro/elim/dest
  4878 attributes; useful for building new logics, but beware of confusion
  4879 with the version in Provers/classical;
  4880 
  4881 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4882 case name 'antecedent';
  4883 
  4884 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4885 to the current context is now done automatically);
  4886 
  4887 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4888 for definining proof methods in ML;
  4889 
  4890 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4891 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4892 most cases, one should have to change intro!! to intro? only);
  4893 replaced "delrule" by "rule del";
  4894 
  4895 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4896 'symmetric' attribute (the latter supercedes [RS sym]);
  4897 
  4898 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4899 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4900 well (including splits);
  4901 
  4902 * Isar/Provers: Simplifier and Classical methods now support all kind
  4903 of modifiers used in the past, including 'cong', 'iff', etc.
  4904 
  4905 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4906 of Simplifier and Classical reasoner);
  4907 
  4908 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4909 now support named cases; major packages (inductive, datatype, primrec,
  4910 recdef) support case names and properly name parameters;
  4911 
  4912 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4913 monotonicity conditions are extracted to be proven at end of
  4914 calculations;
  4915 
  4916 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4917 method anyway;
  4918 
  4919 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4920 split_if split_if_asm; datatype package provides theorems foo.splits =
  4921 foo.split foo.split_asm for each datatype;
  4922 
  4923 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4924 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4925 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4926 use "(cases (simplified))" method in proper proof texts);
  4927 
  4928 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4929 
  4930 * Isar: names of theorems etc. may be natural numbers as well;
  4931 
  4932 * Isar: 'pr' command: optional arguments for goals_limit and
  4933 ProofContext.prems_limit; no longer prints theory contexts, but only
  4934 proof states;
  4935 
  4936 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4937 additional print modes to be specified; e.g. "pr(latex)" will print
  4938 proof state according to the Isabelle LaTeX style;
  4939 
  4940 * Isar: improved support for emulating tactic scripts, including proof
  4941 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4942 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4943 (for HOL datatypes);
  4944 
  4945 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4946 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4947 'proof method scripts' have to be in depth-first order;
  4948 
  4949 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4950 
  4951 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4952 should instead use individual commands for printing items
  4953 (print_commands, print_methods etc.);
  4954 
  4955 * Isar: added 'nothing' --- the empty list of theorems;
  4956 
  4957 
  4958 *** HOL ***
  4959 
  4960 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4961 corresponding virtual machine and a specification of its bytecode
  4962 verifier and a lightweight bytecode verifier, including proofs of
  4963 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4964 Cornelia Pusch (see also the homepage of project Bali at
  4965 http://isabelle.in.tum.de/Bali/);
  4966 
  4967 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4968 Clemens Ballarin;
  4969 
  4970 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4971 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4972 Rasmussen;
  4973 
  4974 * HOL/Lattice: fundamental concepts of lattice theory and order
  4975 structures, including duals, properties of bounds versus algebraic
  4976 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4977 Theorem for complete lattices etc.; may also serve as a demonstration
  4978 for abstract algebraic reasoning using axiomatic type classes, and
  4979 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4980 
  4981 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4982 von Oheimb;
  4983 
  4984 * HOL/IMPP: extension of IMP with local variables and mutually
  4985 recursive procedures, by David von Oheimb;
  4986 
  4987 * HOL/Lambda: converted into new-style theory and document;
  4988 
  4989 * HOL/ex/Multiquote: example of multiple nested quotations and
  4990 anti-quotations -- basically a generalized version of de-Bruijn
  4991 representation; very useful in avoiding lifting of operations;
  4992 
  4993 * HOL/record: added general record equality rule to simpset; fixed
  4994 select-update simplification procedure to handle extended records as
  4995 well; admit "r" as field name;
  4996 
  4997 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4998 other numeric types and also as the identity of groups, rings, etc.;
  4999 
  5000 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  5001 Types nat and int belong to this axclass;
  5002 
  5003 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  5004    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  5005    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  5006   two terms #m*u and #n*u are replaced by #(m+n)*u
  5007     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  5008   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  5009     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  5010 
  5011 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  5012 powerful prover for predicate logic but knows nothing of clasets; see
  5013 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  5014 
  5015 * HOL: new version of "case_tac" subsumes both boolean case split and
  5016 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  5017 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  5018 
  5019 * HOL: simplification no longer dives into case-expressions: only the
  5020 selector expression is simplified, but not the remaining arms; to
  5021 enable full simplification of case-expressions for datatype t, you may
  5022 remove t.weak_case_cong from the simpset, either globally (Delcongs
  5023 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  5024 
  5025 * HOL/recdef: the recursion equations generated by 'recdef' for
  5026 function 'f' are now called f.simps instead of f.rules; if all
  5027 termination conditions are proved automatically, these simplification
  5028 rules are added to the simpset, as in primrec; rules may be named
  5029 individually as well, resulting in a separate list of theorems for
  5030 each equation;
  5031 
  5032 * HOL/While is a new theory that provides a while-combinator. It
  5033 permits the definition of tail-recursive functions without the
  5034 provision of a termination measure. The latter is necessary once the
  5035 invariant proof rule for while is applied.
  5036 
  5037 * HOL: new (overloaded) notation for the set of elements below/above
  5038 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5039 
  5040 * HOL: theorems impI, allI, ballI bound as "strip";
  5041 
  5042 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5043 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5044 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5045 
  5046 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5047 
  5048 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5049 main HOL, but was unused);
  5050 
  5051 * HOL: fewer consts declared as global (e.g. have to refer to
  5052 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5053 
  5054 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5055 in case of overlap with user translations (e.g. judgements over
  5056 tuples); (note that the underlying logical represenation is still
  5057 bogus);
  5058 
  5059 
  5060 *** ZF ***
  5061 
  5062 * ZF: simplification automatically cancels common terms in arithmetic
  5063 expressions over nat and int;
  5064 
  5065 * ZF: new treatment of nat to minimize type-checking: all operators
  5066 coerce their operands to a natural number using the function natify,
  5067 making the algebraic laws unconditional;
  5068 
  5069 * ZF: as above, for int: operators coerce their operands to an integer
  5070 using the function intify;
  5071 
  5072 * ZF: the integer library now contains many of the usual laws for the
  5073 orderings, including $<=, and monotonicity laws for $+ and $*;
  5074 
  5075 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5076 simplification;
  5077 
  5078 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5079 to the simplifier and classical reasoner simultaneously;
  5080 
  5081 
  5082 *** General ***
  5083 
  5084 * Provers: blast_tac now handles actual object-logic rules as
  5085 assumptions; note that auto_tac uses blast_tac internally as well;
  5086 
  5087 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5088 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5089 
  5090 * Provers: delrules now handles destruct rules as well (no longer need
  5091 explicit make_elim);
  5092 
  5093 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5094   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5095 use instead the strong form,
  5096   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5097 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5098 from destruct-rules;
  5099 
  5100 * Provers: Simplifier.easy_setup provides a fast path to basic
  5101 Simplifier setup for new object-logics;
  5102 
  5103 * Pure: AST translation rules no longer require constant head on LHS;
  5104 
  5105 * Pure: improved name spaces: ambiguous output is qualified; support
  5106 for hiding of names;
  5107 
  5108 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5109 XSYMBOL_HOME; no longer need to do manual configuration in most
  5110 situations;
  5111 
  5112 * system: compression of ML heaps images may now be controlled via -c
  5113 option of isabelle and isatool usedir (currently only observed by
  5114 Poly/ML);
  5115 
  5116 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5117 useful for remote X11);
  5118 
  5119 * system: provide TAGS file for Isabelle sources;
  5120 
  5121 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5122 order;
  5123 
  5124 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5125 timing flag supersedes proof_timing and Toplevel.trace;
  5126 
  5127 * ML: new combinators |>> and |>>> for incremental transformations
  5128 with secondary results (e.g. certain theory extensions):
  5129 
  5130 * ML: PureThy.add_defs gets additional argument to indicate potential
  5131 overloading (usually false);
  5132 
  5133 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5134 results;
  5135 
  5136 
  5137 
  5138 New in Isabelle99 (October 1999)
  5139 --------------------------------
  5140 
  5141 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5142 
  5143 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5144 are no longer simplified.  (This allows the simplifier to unfold recursive
  5145 functional programs.)  To restore the old behaviour, declare
  5146 
  5147     Delcongs [if_weak_cong];
  5148 
  5149 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5150 complement;
  5151 
  5152 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5153 
  5154 * HOL/datatype: mutual_induct_tac no longer exists --
  5155   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5156 
  5157 * HOL/typedef: fixed type inference for representing set; type
  5158 arguments now have to occur explicitly on the rhs as type constraints;
  5159 
  5160 * ZF: The con_defs part of an inductive definition may no longer refer
  5161 to constants declared in the same theory;
  5162 
  5163 * HOL, ZF: the function mk_cases, generated by the inductive
  5164 definition package, has lost an argument.  To simplify its result, it
  5165 uses the default simpset instead of a supplied list of theorems.
  5166 
  5167 * HOL/List: the constructors of type list are now Nil and Cons;
  5168 
  5169 * Simplifier: the type of the infix ML functions
  5170         setSSolver addSSolver setSolver addSolver
  5171 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5172 for packaging solvers. A solver is created via
  5173         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5174 where the string argument is only a comment.
  5175 
  5176 
  5177 *** Proof tools ***
  5178 
  5179 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5180 decision procedure for linear arithmetic. Currently it is used for
  5181 types `nat', `int', and `real' in HOL (see below); it can, should and
  5182 will be instantiated for other types and logics as well.
  5183 
  5184 * The simplifier now accepts rewrite rules with flexible heads, eg
  5185      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5186   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5187   matching.
  5188 
  5189 
  5190 *** General ***
  5191 
  5192 * New Isabelle/Isar subsystem provides an alternative to traditional
  5193 tactical theorem proving; together with the ProofGeneral/isar user
  5194 interface it offers an interactive environment for developing human
  5195 readable proof documents (Isar == Intelligible semi-automated
  5196 reasoning); for further information see isatool doc isar-ref,
  5197 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5198 
  5199 * improved and simplified presentation of theories: better HTML markup
  5200 (including colors), graph views in several sizes; isatool usedir now
  5201 provides a proper interface for user theories (via -P option); actual
  5202 document preparation based on (PDF)LaTeX is available as well (for
  5203 new-style theories only); see isatool doc system for more information;
  5204 
  5205 * native support for Proof General, both for classic Isabelle and
  5206 Isabelle/Isar;
  5207 
  5208 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5209 using the graph browser tool;
  5210 
  5211 * Isabelle manuals now also available as PDF;
  5212 
  5213 * theory loader rewritten from scratch (may not be fully
  5214 bug-compatible); old loadpath variable has been replaced by show_path,
  5215 add_path, del_path, reset_path functions; new operations such as
  5216 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5217 isatool doc ref);
  5218 
  5219 * improved isatool install: option -k creates KDE application icon,
  5220 option -p DIR installs standalone binaries;
  5221 
  5222 * added ML_PLATFORM setting (useful for cross-platform installations);
  5223 more robust handling of platform specific ML images for SML/NJ;
  5224 
  5225 * the settings environment is now statically scoped, i.e. it is never
  5226 created again in sub-processes invoked from isabelle, isatool, or
  5227 Isabelle;
  5228 
  5229 * path element specification '~~' refers to '$ISABELLE_HOME';
  5230 
  5231 * in locales, the "assumes" and "defines" parts may be omitted if
  5232 empty;
  5233 
  5234 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5235 long arrows);
  5236 
  5237 * new print_mode "HTML";
  5238 
  5239 * new flag show_tags controls display of tags of theorems (which are
  5240 basically just comments that may be attached by some tools);
  5241 
  5242 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5243 mode and goal output format:
  5244 
  5245 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5246 244c244
  5247 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5248 ---
  5249 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5250 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5251 181c181
  5252 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5253 ---
  5254 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5255 
  5256 * function bind_thms stores lists of theorems (cf. bind_thm);
  5257 
  5258 * new shorthand tactics ftac, eatac, datac, fatac;
  5259 
  5260 * qed (and friends) now accept "" as result name; in that case the
  5261 theorem is not stored, but proper checks and presentation of the
  5262 result still apply;
  5263 
  5264 * theorem database now also indexes constants "Trueprop", "all",
  5265 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5266 
  5267 
  5268 *** HOL ***
  5269 
  5270 ** HOL arithmetic **
  5271 
  5272 * There are now decision procedures for linear arithmetic over nat and
  5273 int:
  5274 
  5275 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5276 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5277 are treated as atomic; subformulae not involving type `nat' or `int'
  5278 are ignored; quantified subformulae are ignored unless they are
  5279 positive universal or negative existential. The tactic has to be
  5280 invoked by hand and can be a little bit slow. In particular, the
  5281 running time is exponential in the number of occurrences of `min' and
  5282 `max', and `-' on `nat'.
  5283 
  5284 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5285 (negated) (in)equalities among the premises and the conclusion into
  5286 account (i.e. no compound formulae) and does not know about `min' and
  5287 `max', and `-' on `nat'. It is fast and is used automatically by the
  5288 simplifier.
  5289 
  5290 NB: At the moment, these decision procedures do not cope with mixed
  5291 nat/int formulae where the two parts interact, such as `m < n ==>
  5292 int(m) < int(n)'.
  5293 
  5294 * HOL/Numeral provides a generic theory of numerals (encoded
  5295 efficiently as bit strings); setup for types nat/int/real is in place;
  5296 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5297 int, existing theories and proof scripts may require a few additional
  5298 type constraints;
  5299 
  5300 * integer division and remainder can now be performed on constant
  5301 arguments;
  5302 
  5303 * many properties of integer multiplication, division and remainder
  5304 are now available;
  5305 
  5306 * An interface to the Stanford Validity Checker (SVC) is available through the
  5307 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5308 are proved automatically.  SVC must be installed separately, and its results
  5309 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5310 invocation of the underlying oracle).  For SVC see
  5311   http://verify.stanford.edu/SVC
  5312 
  5313 * IsaMakefile: the HOL-Real target now builds an actual image;
  5314 
  5315 
  5316 ** HOL misc **
  5317 
  5318 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5319 (in Isabelle/Isar) -- by Gertrud Bauer;
  5320 
  5321 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5322 analysis for assembly languages with subtypes;
  5323 
  5324 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5325 -- avoids syntactic ambiguities and treats state, transition, and
  5326 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5327 changed syntax and (many) tactics;
  5328 
  5329 * HOL/inductive: Now also handles more general introduction rules such
  5330   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5331   theorems are now maintained within the theory (maintained via the
  5332   "mono" attribute);
  5333 
  5334 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5335   (using function types) such as
  5336 
  5337   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5338 
  5339 * HOL/record: record_simproc (part of the default simpset) takes care
  5340 of selectors applied to updated records; record_split_tac is no longer
  5341 part of the default claset; update_defs may now be removed from the
  5342 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5343 
  5344   claset_ref () := claset() addSWrapper record_split_wrapper;
  5345   Delsimprocs [record_simproc]
  5346 
  5347 * HOL/typedef: fixed type inference for representing set; type
  5348 arguments now have to occur explicitly on the rhs as type constraints;
  5349 
  5350 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5351 names rather than an ML expression;
  5352 
  5353 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5354 supplied later.  Program schemes can be defined, such as
  5355     "While B C s = (if B s then While B C (C s) else s)"
  5356 where the well-founded relation can be chosen after B and C have been given.
  5357 
  5358 * HOL/List: the constructors of type list are now Nil and Cons;
  5359 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5360 course, ML tools referring to List.list.op # etc. have to be adapted;
  5361 
  5362 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5363 disabled by default; run isabelle with option -m HOL to get back to
  5364 the original Gordon/HOL-style output;
  5365 
  5366 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5367 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5368 
  5369 * HOL basic syntax simplified (more orthogonal): all variants of
  5370 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5371 Eps operator is provided as well: "SOME x. P[x]";
  5372 
  5373 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5374 
  5375 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5376 thus available for user theories;
  5377 
  5378 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5379 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5380 time;
  5381 
  5382 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5383 several times and then mp;
  5384 
  5385 
  5386 *** LK ***
  5387 
  5388 * the notation <<...>> is now available as a notation for sequences of
  5389 formulas;
  5390 
  5391 * the simplifier is now installed
  5392 
  5393 * the axiom system has been generalized (thanks to Soren Heilmann)
  5394 
  5395 * the classical reasoner now has a default rule database
  5396 
  5397 
  5398 *** ZF ***
  5399 
  5400 * new primrec section allows primitive recursive functions to be given
  5401 directly (as in HOL) over datatypes and the natural numbers;
  5402 
  5403 * new tactics induct_tac and exhaust_tac for induction (or case
  5404 analysis) over datatypes and the natural numbers;
  5405 
  5406 * the datatype declaration of type T now defines the recursor T_rec;
  5407 
  5408 * simplification automatically does freeness reasoning for datatype
  5409 constructors;
  5410 
  5411 * automatic type-inference, with AddTCs command to insert new
  5412 type-checking rules;
  5413 
  5414 * datatype introduction rules are now added as Safe Introduction rules
  5415 to the claset;
  5416 
  5417 * the syntax "if P then x else y" is now available in addition to
  5418 if(P,x,y);
  5419 
  5420 
  5421 *** Internal programming interfaces ***
  5422 
  5423 * tuned simplifier trace output; new flag debug_simp;
  5424 
  5425 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5426 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5427 
  5428 * AxClass.axclass_tac lost the theory argument;
  5429 
  5430 * tuned current_goals_markers semantics: begin / end goal avoids
  5431 printing empty lines;
  5432 
  5433 * removed prs and prs_fn hook, which was broken because it did not
  5434 include \n in its semantics, forcing writeln to add one
  5435 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5436 string -> unit if you really want to output text without newline;
  5437 
  5438 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5439 plain output, interface builders may have to enable 'isabelle_font'
  5440 mode to get Isabelle font glyphs as before;
  5441 
  5442 * refined token_translation interface; INCOMPATIBILITY: output length
  5443 now of type real instead of int;
  5444 
  5445 * theory loader actions may be traced via new ThyInfo.add_hook
  5446 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5447 your own database of information attached to *whole* theories -- as
  5448 opposed to intra-theory data slots offered via TheoryDataFun;
  5449 
  5450 * proper handling of dangling sort hypotheses (at last!);
  5451 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5452 extra sort hypotheses that can be witnessed from the type signature;
  5453 the force_strip_shyps flag is gone, any remaining shyps are simply
  5454 left in the theorem (with a warning issued by strip_shyps_warning);
  5455 
  5456 
  5457 
  5458 New in Isabelle98-1 (October 1998)
  5459 ----------------------------------
  5460 
  5461 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5462 
  5463 * several changes of automated proof tools;
  5464 
  5465 * HOL: major changes to the inductive and datatype packages, including
  5466 some minor incompatibilities of theory syntax;
  5467 
  5468 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5469 called `inj_on';
  5470 
  5471 * HOL: removed duplicate thms in Arith:
  5472   less_imp_add_less  should be replaced by  trans_less_add1
  5473   le_imp_add_le      should be replaced by  trans_le_add1
  5474 
  5475 * HOL: unary minus is now overloaded (new type constraints may be
  5476 required);
  5477 
  5478 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5479 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5480 now taken as an integer constant.
  5481 
  5482 * Pure: ML function 'theory_of' renamed to 'theory';
  5483 
  5484 
  5485 *** Proof tools ***
  5486 
  5487 * Simplifier:
  5488   1. Asm_full_simp_tac is now more aggressive.
  5489      1. It will sometimes reorient premises if that increases their power to
  5490         simplify.
  5491      2. It does no longer proceed strictly from left to right but may also
  5492         rotate premises to achieve further simplification.
  5493      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5494      old Asm_full_simp_tac in that it does not rotate premises.
  5495   2. The simplifier now knows a little bit about nat-arithmetic.
  5496 
  5497 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5498 allows for selected deletion of wrappers, by introduction of names for
  5499 wrapper functionals.  This implies that addbefore, addSbefore,
  5500 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5501 and that adding two tactics with the same name overwrites the first
  5502 one (emitting a warning).
  5503   type wrapper = (int -> tactic) -> (int -> tactic)
  5504   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5505   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5506   delWrapper, delSWrapper: claset *  string            -> claset
  5507   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5508 
  5509 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5510 semantics; addbefore now affects only the unsafe part of step_tac
  5511 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5512 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5513 by Force_tac;
  5514 
  5515 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5516 compWrapper; added safe wrapper (and access functions for it);
  5517 
  5518 * HOL/split_all_tac is now much faster and fails if there is nothing
  5519 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5520 and the names of the automatically generated variables have changed.
  5521 split_all_tac has moved within claset() from unsafe wrappers to safe
  5522 wrappers, which means that !!-bound variables are split much more
  5523 aggressively, and safe_tac and clarify_tac now split such variables.
  5524 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5525 Note: the same holds for record_split_tac, which does the job of
  5526 split_all_tac for record fields.
  5527 
  5528 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5529 permanently to the default simpset using Addsplits just like
  5530 Addsimps. They can be removed via Delsplits just like
  5531 Delsimps. Lower-case versions are also available.
  5532 
  5533 * HOL/Simplifier: The rule split_if is now part of the default
  5534 simpset. This means that the simplifier will eliminate all occurrences
  5535 of if-then-else in the conclusion of a goal. To prevent this, you can
  5536 either remove split_if completely from the default simpset by
  5537 `Delsplits [split_if]' or remove it in a specific call of the
  5538 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5539 other case splitting rules to/from the default simpset: every datatype
  5540 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5541 t is the name of the datatype).
  5542 
  5543 * Classical reasoner / Simplifier combination: new force_tac (and
  5544 derivatives Force_tac, force) combines rewriting and classical
  5545 reasoning (and whatever other tools) similarly to auto_tac, but is
  5546 aimed to solve the given subgoal completely.
  5547 
  5548 
  5549 *** General ***
  5550 
  5551 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5552 and `goalw': the theory is no longer needed as an explicit argument -
  5553 the current theory context is used; assumptions are no longer returned
  5554 at the ML-level unless one of them starts with ==> or !!; it is
  5555 recommended to convert to these new commands using isatool fixgoal
  5556 (backup your sources first!);
  5557 
  5558 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5559 the current theory context, and 'theory' to lookup stored theories;
  5560 
  5561 * new theory section 'locale' for declaring constants, assumptions and
  5562 definitions that have local scope;
  5563 
  5564 * new theory section 'nonterminals' for purely syntactic types;
  5565 
  5566 * new theory section 'setup' for generic ML setup functions
  5567 (e.g. package initialization);
  5568 
  5569 * the distribution now includes Isabelle icons: see
  5570 lib/logo/isabelle-{small,tiny}.xpm;
  5571 
  5572 * isatool install - install binaries with absolute references to
  5573 ISABELLE_HOME/bin;
  5574 
  5575 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5576 
  5577 * print mode 'emacs' reserved for Isamode;
  5578 
  5579 * support multiple print (ast) translations per constant name;
  5580 
  5581 * theorems involving oracles are now printed with a suffixed [!];
  5582 
  5583 
  5584 *** HOL ***
  5585 
  5586 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5587 
  5588 * HOL/inductive package reorganized and improved: now supports mutual
  5589 definitions such as
  5590 
  5591   inductive EVEN ODD
  5592     intrs
  5593       null "0 : EVEN"
  5594       oddI "n : EVEN ==> Suc n : ODD"
  5595       evenI "n : ODD ==> Suc n : EVEN"
  5596 
  5597 new theorem list "elims" contains an elimination rule for each of the
  5598 recursive sets; inductive definitions now handle disjunctive premises
  5599 correctly (also ZF);
  5600 
  5601 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5602 "mutual_induct" no longer exists - the induction rule is always
  5603 contained in "induct";
  5604 
  5605 
  5606 * HOL/datatype package re-implemented and greatly improved: now
  5607 supports mutually recursive datatypes such as
  5608 
  5609   datatype
  5610     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5611             | SUM ('a aexp) ('a aexp)
  5612             | DIFF ('a aexp) ('a aexp)
  5613             | NUM 'a
  5614   and
  5615     'a bexp = LESS ('a aexp) ('a aexp)
  5616             | AND ('a bexp) ('a bexp)
  5617             | OR ('a bexp) ('a bexp)
  5618 
  5619 as well as indirectly recursive datatypes such as
  5620 
  5621   datatype
  5622     ('a, 'b) term = Var 'a
  5623                   | App 'b ((('a, 'b) term) list)
  5624 
  5625 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5626 induction on mutually / indirectly recursive datatypes.
  5627 
  5628 Primrec equations are now stored in theory and can be accessed via
  5629 <function_name>.simps.
  5630 
  5631 INCOMPATIBILITIES:
  5632 
  5633   - Theories using datatypes must now have theory Datatype as an
  5634     ancestor.
  5635   - The specific <typename>.induct_tac no longer exists - use the
  5636     generic induct_tac instead.
  5637   - natE has been renamed to nat.exhaust - use exhaust_tac
  5638     instead of res_inst_tac ... natE. Note that the variable
  5639     names in nat.exhaust differ from the names in natE, this
  5640     may cause some "fragile" proofs to fail.
  5641   - The theorems split_<typename>_case and split_<typename>_case_asm
  5642     have been renamed to <typename>.split and <typename>.split_asm.
  5643   - Since default sorts of type variables are now handled correctly,
  5644     some datatype definitions may have to be annotated with explicit
  5645     sort constraints.
  5646   - Primrec definitions no longer require function name and type
  5647     of recursive argument.
  5648 
  5649 Consider using isatool fixdatatype to adapt your theories and proof
  5650 scripts to the new package (backup your sources first!).
  5651 
  5652 
  5653 * HOL/record package: considerably improved implementation; now
  5654 includes concrete syntax for record types, terms, updates; theorems
  5655 for surjective pairing and splitting !!-bound record variables; proof
  5656 support is as follows:
  5657 
  5658   1) standard conversions (selectors or updates applied to record
  5659 constructor terms) are part of the standard simpset;
  5660 
  5661   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5662 made part of standard simpset and claset via addIffs;
  5663 
  5664   3) a tactic for record field splitting (record_split_tac) is part of
  5665 the standard claset (addSWrapper);
  5666 
  5667 To get a better idea about these rules you may retrieve them via
  5668 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5669 the name of your record type.
  5670 
  5671 The split tactic 3) conceptually simplifies by the following rule:
  5672 
  5673   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5674 
  5675 Thus any record variable that is bound by meta-all will automatically
  5676 blow up into some record constructor term, consequently the
  5677 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5678 solve record problems automatically.
  5679 
  5680 
  5681 * reorganized the main HOL image: HOL/Integ and String loaded by
  5682 default; theory Main includes everything;
  5683 
  5684 * automatic simplification of integer sums and comparisons, using cancellation;
  5685 
  5686 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5687 
  5688 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5689 
  5690 * many new identities for unions, intersections, set difference, etc.;
  5691 
  5692 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5693 called split_if, split_split, split_sum_case and split_nat_case (to go
  5694 with add/delsplits);
  5695 
  5696 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5697 (?x::unit) = (); this is made part of the default simpset, which COULD
  5698 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5699 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5700 unit_abs_eta_conv is added in order to counter the effect of
  5701 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5702 %u.f();
  5703 
  5704 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5705 makes more sense);
  5706 
  5707 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5708   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5709   disjointness reasoning but breaking a few old proofs.
  5710 
  5711 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5712 to 'converse' from 'inverse' (for compatibility with ZF and some
  5713 literature);
  5714 
  5715 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5716 the well-founded relation;
  5717 
  5718 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5719     Compl A.  The "Compl" syntax remains available as input syntax for this
  5720     release ONLY.
  5721 
  5722 * HOL/Update: new theory of function updates:
  5723     f(a:=b) == %x. if x=a then b else f x
  5724 may also be iterated as in f(a:=b,c:=d,...);
  5725 
  5726 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5727 
  5728 * HOL/List:
  5729   - new function list_update written xs[i:=v] that updates the i-th
  5730     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5731   - new function `upt' written [i..j(] which generates the list
  5732     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5733     bound write [i..j], which is a shorthand for [i..j+1(].
  5734   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5735 
  5736 * HOL/Arith:
  5737   - removed 'pred' (predecessor) function;
  5738   - generalized some theorems about n-1;
  5739   - many new laws about "div" and "mod";
  5740   - new laws about greatest common divisors (see theory ex/Primes);
  5741 
  5742 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5743 instead of "inverse";
  5744 
  5745 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5746   of the multiset ordering;
  5747 
  5748 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5749   (not included by default);
  5750 
  5751 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5752 
  5753 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5754   programs, i.e. different program variables may have different types.
  5755 
  5756 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5757   [previously, this check worked only if the rewrite rule was unconditional]
  5758   Now rew can involve either definitions or equalities (either == or =).
  5759 
  5760 
  5761 *** ZF ***
  5762 
  5763 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5764   only the theorems proved on ZF.ML;
  5765 
  5766 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5767   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5768   disjointness reasoning but breaking a few old proofs.
  5769 
  5770 * ZF/Update: new theory of function updates
  5771     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5772   may also be iterated as in f(a:=b,c:=d,...);
  5773 
  5774 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5775 
  5776 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5777   [previously, this check worked only if the rewrite rule was unconditional]
  5778   Now rew can involve either definitions or equalities (either == or =).
  5779 
  5780 * case_tac provided for compatibility with HOL
  5781     (like the old excluded_middle_tac, but with subgoals swapped)
  5782 
  5783 
  5784 *** Internal programming interfaces ***
  5785 
  5786 * Pure: several new basic modules made available for general use, see
  5787 also src/Pure/README;
  5788 
  5789 * improved the theory data mechanism to support encapsulation (data
  5790 kind name replaced by private Object.kind, acting as authorization
  5791 key); new type-safe user interface via functor TheoryDataFun; generic
  5792 print_data function becomes basically useless;
  5793 
  5794 * removed global_names compatibility flag -- all theory declarations
  5795 are qualified by default;
  5796 
  5797 * module Pure/Syntax now offers quote / antiquote translation
  5798 functions (useful for Hoare logic etc. with implicit dependencies);
  5799 see HOL/ex/Antiquote for an example use;
  5800 
  5801 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5802 cterm -> thm;
  5803 
  5804 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5805 subgoal;
  5806 
  5807 * Display.print_goals function moved to Locale.print_goals;
  5808 
  5809 * standard print function for goals supports current_goals_markers
  5810 variable for marking begin of proof, end of proof, start of goal; the
  5811 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5812 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5813 for example;
  5814 
  5815 
  5816 
  5817 New in Isabelle98 (January 1998)
  5818 --------------------------------
  5819 
  5820 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5821 
  5822 * changed lexical syntax of terms / types: dots made part of long
  5823 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5824 
  5825 * simpset (and claset) reference variable replaced by functions
  5826 simpset / simpset_ref;
  5827 
  5828 * no longer supports theory aliases (via merge) and non-trivial
  5829 implicit merge of thms' signatures;
  5830 
  5831 * most internal names of constants changed due to qualified names;
  5832 
  5833 * changed Pure/Sequence interface (see Pure/seq.ML);
  5834 
  5835 
  5836 *** General Changes ***
  5837 
  5838 * hierachically structured name spaces (for consts, types, axms, thms
  5839 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5840 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5841 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5842 long_names for fully qualified output names; NOTE: ML programs
  5843 (special tactics, packages etc.) referring to internal names may have
  5844 to be adapted to cope with fully qualified names; in case of severe
  5845 backward campatibility problems try setting 'global_names' at compile
  5846 time to have enrything declared within a flat name space; one may also
  5847 fine tune name declarations in theories via the 'global' and 'local'
  5848 section;
  5849 
  5850 * reimplemented the implicit simpset and claset using the new anytype
  5851 data filed in signatures; references simpset:simpset ref etc. are
  5852 replaced by functions simpset:unit->simpset and
  5853 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5854 to patch your ML files accordingly;
  5855 
  5856 * HTML output now includes theory graph data for display with Java
  5857 applet or isatool browser; data generated automatically via isatool
  5858 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5859 
  5860 * defs may now be conditional; improved rewrite_goals_tac to handle
  5861 conditional equations;
  5862 
  5863 * defs now admits additional type arguments, using TYPE('a) syntax;
  5864 
  5865 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5866 creates a new theory node; implicit merge of thms' signatures is
  5867 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5868 transfer:theory->thm->thm in (rare) cases;
  5869 
  5870 * improved handling of draft signatures / theories; draft thms (and
  5871 ctyps, cterms) are automatically promoted to real ones;
  5872 
  5873 * slightly changed interfaces for oracles: admit many per theory, named
  5874 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5875 
  5876 * print_goals: optional output of const types (set show_consts and
  5877 show_types);
  5878 
  5879 * improved output of warnings (###) and errors (***);
  5880 
  5881 * subgoal_tac displays a warning if the new subgoal has type variables;
  5882 
  5883 * removed old README and Makefiles;
  5884 
  5885 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5886 
  5887 * removed obsolete init_pps and init_database;
  5888 
  5889 * deleted the obsolete tactical STATE, which was declared by
  5890     fun STATE tacfun st = tacfun st st;
  5891 
  5892 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5893 (which abbreviates $HOME);
  5894 
  5895 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5896 use isatool fixseq to adapt your ML programs (this works for fully
  5897 qualified references to the Sequence structure only!);
  5898 
  5899 * use_thy no longer requires writable current directory; it always
  5900 reloads .ML *and* .thy file, if either one is out of date;
  5901 
  5902 
  5903 *** Classical Reasoner ***
  5904 
  5905 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5906 tactics that use classical reasoning to simplify a subgoal without
  5907 splitting it into several subgoals;
  5908 
  5909 * Safe_tac: like safe_tac but uses the default claset;
  5910 
  5911 
  5912 *** Simplifier ***
  5913 
  5914 * added simplification meta rules:
  5915     (asm_)(full_)simplify: simpset -> thm -> thm;
  5916 
  5917 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5918 logics (again);
  5919 
  5920 * added prems argument to simplification procedures;
  5921 
  5922 * HOL, FOL, ZF: added infix function `addsplits':
  5923   instead of `<simpset> setloop (split_tac <thms>)'
  5924   you can simply write `<simpset> addsplits <thms>'
  5925 
  5926 
  5927 *** Syntax ***
  5928 
  5929 * TYPE('a) syntax for type reflection terms;
  5930 
  5931 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5932 
  5933 * pretty printer: changed order of mixfix annotation preference (again!);
  5934 
  5935 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5936 
  5937 
  5938 *** HOL ***
  5939 
  5940 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5941   with `addloop' of the simplifier to faciliate case splitting in premises.
  5942 
  5943 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5944 
  5945 * HOL/Auth: new protocol proofs including some for the Internet
  5946   protocol TLS;
  5947 
  5948 * HOL/Map: new theory of `maps' a la VDM;
  5949 
  5950 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5951 cancelling out common nat summands from =, <, <= (in)equalities, or
  5952 differences; simplification procedures nat_cancel_factor for
  5953 cancelling common factor from =, <, <= (in)equalities over natural
  5954 sums; nat_cancel contains both kinds of procedures, it is installed by
  5955 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5956 
  5957 * HOL/simplifier: terms of the form
  5958   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5959   are rewritten to
  5960   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5961   and those of the form
  5962   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5963   are rewritten to
  5964   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5965 
  5966 * HOL/datatype
  5967   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5968 
  5969   P(t_case f1 ... fn x) =
  5970      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5971         ...
  5972        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5973      )
  5974 
  5975   and a theorem `split_t_case_asm' of the form
  5976 
  5977   P(t_case f1 ... fn x) =
  5978     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5979         ...
  5980        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5981      )
  5982   which can be added to a simpset via `addsplits'. The existing theorems
  5983   expand_list_case and expand_option_case have been renamed to
  5984   split_list_case and split_option_case.
  5985 
  5986 * HOL/Arithmetic:
  5987   - `pred n' is automatically converted to `n-1'.
  5988     Users are strongly encouraged not to use `pred' any longer,
  5989     because it will disappear altogether at some point.
  5990   - Users are strongly encouraged to write "0 < n" rather than
  5991     "n ~= 0". Theorems and proof tools have been modified towards this
  5992     `standard'.
  5993 
  5994 * HOL/Lists:
  5995   the function "set_of_list" has been renamed "set" (and its theorems too);
  5996   the function "nth" now takes its arguments in the reverse order and
  5997   has acquired the infix notation "!" as in "xs!n".
  5998 
  5999 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  6000 
  6001 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  6002   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  6003 
  6004 * HOL/record: extensible records with schematic structural subtyping
  6005 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  6006 still lacks various theorems and concrete record syntax;
  6007 
  6008 
  6009 *** HOLCF ***
  6010 
  6011 * removed "axioms" and "generated by" sections;
  6012 
  6013 * replaced "ops" section by extended "consts" section, which is capable of
  6014   handling the continuous function space "->" directly;
  6015 
  6016 * domain package:
  6017   . proves theorems immediately and stores them in the theory,
  6018   . creates hierachical name space,
  6019   . now uses normal mixfix annotations (instead of cinfix...),
  6020   . minor changes to some names and values (for consistency),
  6021   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  6022   . separator between mutual domain defs: changed "," to "and",
  6023   . improved handling of sort constraints;  now they have to
  6024     appear on the left-hand side of the equations only;
  6025 
  6026 * fixed LAM <x,y,zs>.b syntax;
  6027 
  6028 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  6029 adm (%x. P (t x)), where P is chainfinite and t continuous;
  6030 
  6031 
  6032 *** FOL and ZF ***
  6033 
  6034 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6035   with `addloop' of the simplifier to faciliate case splitting in premises.
  6036 
  6037 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6038 in HOL, they strip ALL and --> from proved theorems;
  6039 
  6040 
  6041 
  6042 New in Isabelle94-8 (May 1997)
  6043 ------------------------------
  6044 
  6045 *** General Changes ***
  6046 
  6047 * new utilities to build / run / maintain Isabelle etc. (in parts
  6048 still somewhat experimental); old Makefiles etc. still functional;
  6049 
  6050 * new 'Isabelle System Manual';
  6051 
  6052 * INSTALL text, together with ./configure and ./build scripts;
  6053 
  6054 * reimplemented type inference for greater efficiency, better error
  6055 messages and clean internal interface;
  6056 
  6057 * prlim command for dealing with lots of subgoals (an easier way of
  6058 setting goals_limit);
  6059 
  6060 
  6061 *** Syntax ***
  6062 
  6063 * supports alternative (named) syntax tables (parser and pretty
  6064 printer); internal interface is provided by add_modesyntax(_i);
  6065 
  6066 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6067 be used in conjunction with the Isabelle symbol font; uses the
  6068 "symbols" syntax table;
  6069 
  6070 * added token_translation interface (may translate name tokens in
  6071 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6072 the current print_mode); IMPORTANT: user print translation functions
  6073 are responsible for marking newly introduced bounds
  6074 (Syntax.mark_boundT);
  6075 
  6076 * token translations for modes "xterm" and "xterm_color" that display
  6077 names in bold, underline etc. or colors (which requires a color
  6078 version of xterm);
  6079 
  6080 * infixes may now be declared with names independent of their syntax;
  6081 
  6082 * added typed_print_translation (like print_translation, but may
  6083 access type of constant);
  6084 
  6085 
  6086 *** Classical Reasoner ***
  6087 
  6088 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6089 some limitations.  Blast_tac...
  6090   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6091   + ignores elimination rules that don't have the correct format
  6092         (the conclusion MUST be a formula variable)
  6093   + ignores types, which can make HOL proofs fail
  6094   + rules must not require higher-order unification, e.g. apply_type in ZF
  6095     [message "Function Var's argument not a bound variable" relates to this]
  6096   + its proof strategy is more general but can actually be slower
  6097 
  6098 * substitution with equality assumptions no longer permutes other
  6099 assumptions;
  6100 
  6101 * minor changes in semantics of addafter (now called addaltern); renamed
  6102 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6103 (and access functions for it);
  6104 
  6105 * improved combination of classical reasoner and simplifier:
  6106   + functions for handling clasimpsets
  6107   + improvement of addss: now the simplifier is called _after_ the
  6108     safe steps.
  6109   + safe variant of addss called addSss: uses safe simplifications
  6110     _during_ the safe steps. It is more complete as it allows multiple
  6111     instantiations of unknowns (e.g. with slow_tac).
  6112 
  6113 *** Simplifier ***
  6114 
  6115 * added interface for simplification procedures (functions that
  6116 produce *proven* rewrite rules on the fly, depending on current
  6117 redex);
  6118 
  6119 * ordering on terms as parameter (used for ordered rewriting);
  6120 
  6121 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6122 
  6123 * the solver is now split into a safe and an unsafe part.
  6124 This should be invisible for the normal user, except that the
  6125 functions setsolver and addsolver have been renamed to setSolver and
  6126 addSolver; added safe_asm_full_simp_tac;
  6127 
  6128 
  6129 *** HOL ***
  6130 
  6131 * a generic induction tactic `induct_tac' which works for all datatypes and
  6132 also for type `nat';
  6133 
  6134 * a generic case distinction tactic `exhaust_tac' which works for all
  6135 datatypes and also for type `nat';
  6136 
  6137 * each datatype comes with a function `size';
  6138 
  6139 * patterns in case expressions allow tuple patterns as arguments to
  6140 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6141 
  6142 * primrec now also works with type nat;
  6143 
  6144 * recdef: a new declaration form, allows general recursive functions to be
  6145 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6146 
  6147 * the constant for negation has been renamed from "not" to "Not" to
  6148 harmonize with FOL, ZF, LK, etc.;
  6149 
  6150 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6151 infinite lists;
  6152 
  6153 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6154 
  6155 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6156 problems in commutative rings, using axiomatic type classes for + and *;
  6157 
  6158 * more examples in HOL/MiniML and HOL/Auth;
  6159 
  6160 * more default rewrite rules for quantifiers, union/intersection;
  6161 
  6162 * a new constant `arbitrary == @x.False';
  6163 
  6164 * HOLCF/IOA replaces old HOL/IOA;
  6165 
  6166 * HOLCF changes: derived all rules and arities
  6167   + axiomatic type classes instead of classes
  6168   + typedef instead of faking type definitions
  6169   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6170   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6171   + eliminated the types void, one, tr
  6172   + use unit lift and bool lift (with translations) instead of one and tr
  6173   + eliminated blift from Lift3.thy (use Def instead of blift)
  6174   all eliminated rules are derived as theorems --> no visible changes ;
  6175 
  6176 
  6177 *** ZF ***
  6178 
  6179 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6180 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6181 as ZF_cs addSIs [equalityI];
  6182 
  6183 
  6184 
  6185 New in Isabelle94-7 (November 96)
  6186 ---------------------------------
  6187 
  6188 * allowing negative levels (as offsets) in prlev and choplev;
  6189 
  6190 * super-linear speedup for large simplifications;
  6191 
  6192 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6193 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6194 FAIL); can suppress it using the command Delsimps (ex_simps @
  6195 all_simps); De Morgan laws are also now included, by default;
  6196 
  6197 * improved printing of ==>  :  ~:
  6198 
  6199 * new object-logic "Sequents" adds linear logic, while replacing LK
  6200 and Modal (thanks to Sara Kalvala);
  6201 
  6202 * HOL/Auth: correctness proofs for authentication protocols;
  6203 
  6204 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6205 examples on HOL/Auth);
  6206 
  6207 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6208 the rewriter and classical reasoner simultaneously;
  6209 
  6210 * function uresult no longer returns theorems in "standard" format;
  6211 regain previous version by: val uresult = standard o uresult;
  6212 
  6213 
  6214 
  6215 New in Isabelle94-6
  6216 -------------------
  6217 
  6218 * oracles -- these establish an interface between Isabelle and trusted
  6219 external reasoners, which may deliver results as theorems;
  6220 
  6221 * proof objects (in particular record all uses of oracles);
  6222 
  6223 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6224 
  6225 * "constdefs" section in theory files;
  6226 
  6227 * "primrec" section (HOL) no longer requires names;
  6228 
  6229 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6230 
  6231 
  6232 
  6233 New in Isabelle94-5
  6234 -------------------
  6235 
  6236 * reduced space requirements;
  6237 
  6238 * automatic HTML generation from theories;
  6239 
  6240 * theory files no longer require "..." (quotes) around most types;
  6241 
  6242 * new examples, including two proofs of the Church-Rosser theorem;
  6243 
  6244 * non-curried (1994) version of HOL is no longer distributed;
  6245 
  6246 
  6247 
  6248 New in Isabelle94-4
  6249 -------------------
  6250 
  6251 * greatly reduced space requirements;
  6252 
  6253 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6254 
  6255 * searchable theorem database (see the section "Retrieving theorems" on
  6256 page 8 of the Reference Manual);
  6257 
  6258 * new examples, including Grabczewski's monumental case study of the
  6259 Axiom of Choice;
  6260 
  6261 * The previous version of HOL renamed to Old_HOL;