NEWS
author haftmann
Mon Jun 08 08:38:49 2009 +0200 (2009-06-08)
changeset 31481 60ae1588f232
parent 31317 1f5740424c69
child 31547 398c0f48a99e
child 31624 4b792a97a1fb
permissions -rw-r--r--
method linarith
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** Pure ***
     8 
     9 * On instantiation of classes, remaining undefined class parameters are
    10 formally declared.  INCOMPATIBILITY.
    11 
    12 
    13 *** HOL ***
    14 
    15 * Class semiring_div requires superclass no_zero_divisors and proof of div_mult_mult1;
    16 theorems div_mult_mult1, div_mult_mult2, div_mult_mult1_if, div_mult_mult1 and
    17 div_mult_mult2 have been generalized to class semiring_div, subsuming former
    18 theorems zdiv_zmult_zmult1, zdiv_zmult_zmult1_if, zdiv_zmult_zmult1 and zdiv_zmult_zmult2.
    19 div_mult_mult1 is now [simp] by default.  INCOMPATIBILITY.
    20 
    21 * Power operations on relations and functions are now one dedicate constant compow with
    22 infix syntax "^^".  Power operations on multiplicative monoids retains syntax "^"
    23 and is now defined generic in class power.  INCOMPATIBILITY.
    24 
    25 * ML antiquotation @{code_datatype} inserts definition of a datatype generated
    26 by the code generator; see Predicate.thy for an example.
    27 
    28 * New method "linarith" invokes existing linear arithmetic decision procedure only.
    29 
    30 
    31 *** ML ***
    32 
    33 * Eliminated old Attrib.add_attributes, Method.add_methods and related
    34 cominators for "args".  INCOMPATIBILITY, need to use simplified
    35 Attrib/Method.setup introduced in Isabelle2009.
    36 
    37 
    38 *** System ***
    39 
    40 * Discontinued support for Poly/ML 4.x versions.
    41 
    42 * Removed "compress" option from isabelle-process and isabelle usedir;
    43 this is always enabled.
    44 
    45 
    46 
    47 New in Isabelle2009 (April 2009)
    48 --------------------------------
    49 
    50 *** General ***
    51 
    52 * Simplified main Isabelle executables, with less surprises on
    53 case-insensitive file-systems (such as Mac OS).
    54 
    55   - The main Isabelle tool wrapper is now called "isabelle" instead of
    56     "isatool."
    57 
    58   - The former "isabelle" alias for "isabelle-process" has been
    59     removed (should rarely occur to regular users).
    60 
    61   - The former "isabelle-interface" and its alias "Isabelle" have been
    62     removed (interfaces are now regular Isabelle tools).
    63 
    64 Within scripts and make files, the Isabelle environment variables
    65 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    66 respectively.  (The latter are still available as legacy feature.)
    67 
    68 The old isabelle-interface wrapper could react in confusing ways if
    69 the interface was uninstalled or changed otherwise.  Individual
    70 interface tool configuration is now more explicit, see also the
    71 Isabelle system manual.  In particular, Proof General is now available
    72 via "isabelle emacs".
    73 
    74 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    75 purge installed copies of Isabelle executables and re-run "isabelle
    76 install -p ...", or use symlinks.
    77 
    78 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    79 old ~/isabelle, which was slightly non-standard and apt to cause
    80 surprises on case-insensitive file-systems (such as Mac OS).
    81 
    82 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    83 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    84 care is required when using older releases of Isabelle.  Note that
    85 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    86 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
    87 
    88 * Proofs of fully specified statements are run in parallel on
    89 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
    90 a regular 4-core machine, if the initial heap space is made reasonably
    91 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
    92 
    93 * The main reference manuals ("isar-ref", "implementation", and
    94 "system") have been updated and extended.  Formally checked references
    95 as hyperlinks are now available uniformly.
    96 
    97 
    98 *** Pure ***
    99 
   100 * Complete re-implementation of locales.  INCOMPATIBILITY in several
   101 respects.  The most important changes are listed below.  See the
   102 Tutorial on Locales ("locales" manual) for details.
   103 
   104 - In locale expressions, instantiation replaces renaming.  Parameters
   105 must be declared in a for clause.  To aid compatibility with previous
   106 parameter inheritance, in locale declarations, parameters that are not
   107 'touched' (instantiation position "_" or omitted) are implicitly added
   108 with their syntax at the beginning of the for clause.
   109 
   110 - Syntax from abbreviations and definitions in locales is available in
   111 locale expressions and context elements.  The latter is particularly
   112 useful in locale declarations.
   113 
   114 - More flexible mechanisms to qualify names generated by locale
   115 expressions.  Qualifiers (prefixes) may be specified in locale
   116 expressions, and can be marked as mandatory (syntax: "name!:") or
   117 optional (syntax "name?:").  The default depends for plain "name:"
   118 depends on the situation where a locale expression is used: in
   119 commands 'locale' and 'sublocale' prefixes are optional, in
   120 'interpretation' and 'interpret' prefixes are mandatory.  The old
   121 implicit qualifiers derived from the parameter names of a locale are
   122 no longer generated.
   123 
   124 - Command "sublocale l < e" replaces "interpretation l < e".  The
   125 instantiation clause in "interpretation" and "interpret" (square
   126 brackets) is no longer available.  Use locale expressions.
   127 
   128 - When converting proof scripts, mandatory qualifiers in
   129 'interpretation' and 'interpret' should be retained by default, even
   130 if this is an INCOMPATIBILITY compared to former behavior.  In the
   131 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   132 in locale expressions range over a single locale instance only.
   133 
   134 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   135 In existing theorem specifications replace the includes element by the
   136 respective context elements of the included locale, omitting those
   137 that are already present in the theorem specification.  Multiple
   138 assume elements of a locale should be replaced by a single one
   139 involving the locale predicate.  In the proof body, declarations (most
   140 notably theorems) may be regained by interpreting the respective
   141 locales in the proof context as required (command "interpret").
   142 
   143 If using "includes" in replacement of a target solely because the
   144 parameter types in the theorem are not as general as in the target,
   145 consider declaring a new locale with additional type constraints on
   146 the parameters (context element "constrains").
   147 
   148 - Discontinued "locale (open)".  INCOMPATIBILITY.
   149 
   150 - Locale interpretation commands no longer attempt to simplify goal.
   151 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   152 methods intro_locales and unfold_locales to clarify.
   153 
   154 - Locale interpretation commands no longer accept interpretation
   155 attributes.  INCOMPATIBILITY.
   156 
   157 * Class declaration: so-called "base sort" must not be given in import
   158 list any longer, but is inferred from the specification.  Particularly
   159 in HOL, write
   160 
   161     class foo = ...
   162 
   163 instead of
   164 
   165     class foo = type + ...
   166 
   167 * Class target: global versions of theorems stemming do not carry a
   168 parameter prefix any longer.  INCOMPATIBILITY.
   169 
   170 * Class 'instance' command no longer accepts attached definitions.
   171 INCOMPATIBILITY, use proper 'instantiation' target instead.
   172 
   173 * Recovered hiding of consts, which was accidentally broken in
   174 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   175 makes c inaccessible; consider using ``hide (open) const c'' instead.
   176 
   177 * Slightly more coherent Pure syntax, with updated documentation in
   178 isar-ref manual.  Removed locales meta_term_syntax and
   179 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   180 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   181 directly in regular applications.
   182 
   183 * There is a new syntactic category "float_const" for signed decimal
   184 fractions (e.g. 123.45 or -123.45).
   185 
   186 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   187 interface with 'setup' command instead.
   188 
   189 * Command 'local_setup' is similar to 'setup', but operates on a local
   190 theory context.
   191 
   192 * The 'axiomatization' command now only works within a global theory
   193 context.  INCOMPATIBILITY.
   194 
   195 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   196 hypotheses.  Sorts required in the course of reasoning need to be
   197 covered by the constraints in the initial statement, completed by the
   198 type instance information of the background theory.  Non-trivial sort
   199 hypotheses, which rarely occur in practice, may be specified via
   200 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   201 
   202   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   203 
   204 The result contains an implicit sort hypotheses as before --
   205 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   206 normalization.
   207 
   208 * Generalized Isar history, with support for linear undo, direct state
   209 addressing etc.
   210 
   211 * Changed defaults for unify configuration options:
   212 
   213   unify_trace_bound = 50 (formerly 25)
   214   unify_search_bound = 60 (formerly 30)
   215 
   216 * Different bookkeeping for code equations (INCOMPATIBILITY):
   217 
   218   a) On theory merge, the last set of code equations for a particular
   219      constant is taken (in accordance with the policy applied by other
   220      parts of the code generator framework).
   221 
   222   b) Code equations stemming from explicit declarations (e.g. code
   223      attribute) gain priority over default code equations stemming
   224      from definition, primrec, fun etc.
   225 
   226 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   227 
   228 * Unified theorem tables for both code generators.  Thus [code
   229 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   230 
   231 * Command 'find_consts' searches for constants based on type and name
   232 patterns, e.g.
   233 
   234     find_consts "_ => bool"
   235 
   236 By default, matching is against subtypes, but it may be restricted to
   237 the whole type.  Searching by name is possible.  Multiple queries are
   238 conjunctive and queries may be negated by prefixing them with a
   239 hyphen:
   240 
   241     find_consts strict: "_ => bool" name: "Int" -"int => int"
   242 
   243 * New 'find_theorems' criterion "solves" matches theorems that
   244 directly solve the current goal (modulo higher-order unification).
   245 
   246 * Auto solve feature for main theorem statements: whenever a new goal
   247 is stated, "find_theorems solves" is called; any theorems that could
   248 solve the lemma directly are listed as part of the goal state.
   249 Cf. associated options in Proof General Isabelle settings menu,
   250 enabled by default, with reasonable timeout for pathological cases of
   251 higher-order unification.
   252 
   253 
   254 *** Document preparation ***
   255 
   256 * Antiquotation @{lemma} now imitates a regular terminal proof,
   257 demanding keyword 'by' and supporting the full method expression
   258 syntax just like the Isar command 'by'.
   259 
   260 
   261 *** HOL ***
   262 
   263 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   264 points Main and Complex_Main remain as before.
   265 
   266 * Logic image HOL-Plain provides a minimal HOL with the most important
   267 tools available (inductive, datatype, primrec, ...).  This facilitates
   268 experimentation and tool development.  Note that user applications
   269 (and library theories) should never refer to anything below theory
   270 Main, as before.
   271 
   272 * Logic image HOL-Main stops at theory Main, and thus facilitates
   273 experimentation due to shorter build times.
   274 
   275 * Logic image HOL-NSA contains theories of nonstandard analysis which
   276 were previously part of former HOL-Complex.  Entry point Hyperreal
   277 remains valid, but theories formerly using Complex_Main should now use
   278 new entry point Hypercomplex.
   279 
   280 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   281 Posix processes.  Avoids potentially expensive forking of the ML
   282 process.  New thread-based implementation also works on non-Unix
   283 platforms (Cygwin).  Provers are no longer hardwired, but defined
   284 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   285 commands are covered in the isar-ref manual.
   286 
   287 * Wrapper scripts for remote SystemOnTPTP service allows to use
   288 sledgehammer without local ATP installation (Vampire etc.). Other
   289 provers may be included via suitable ML wrappers, see also
   290 src/HOL/ATP_Linkup.thy.
   291 
   292 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   293 menu.
   294 
   295 * The metis method no longer fails because the theorem is too trivial
   296 (contains the empty clause).
   297 
   298 * The metis method now fails in the usual manner, rather than raising
   299 an exception, if it determines that it cannot prove the theorem.
   300 
   301 * Method "coherent" implements a prover for coherent logic (see also
   302 src/Tools/coherent.ML).
   303 
   304 * Constants "undefined" and "default" replace "arbitrary".  Usually
   305 "undefined" is the right choice to replace "arbitrary", though
   306 logically there is no difference.  INCOMPATIBILITY.
   307 
   308 * Command "value" now integrates different evaluation mechanisms.  The
   309 result of the first successful evaluation mechanism is printed.  In
   310 square brackets a particular named evaluation mechanisms may be
   311 specified (currently, [SML], [code] or [nbe]).  See further
   312 src/HOL/ex/Eval_Examples.thy.
   313 
   314 * Normalization by evaluation now allows non-leftlinear equations.
   315 Declare with attribute [code nbe].
   316 
   317 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   318 as the structured Isar versions "cases" and "induct", cf. the
   319 corresponding "cases" and "induct" attributes.  Mutual induction rules
   320 are now presented as a list of individual projections
   321 (e.g. foo_bar.inducts for types foo and bar); the old format with
   322 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   323 rare situations a different rule is selected --- notably nested tuple
   324 elimination instead of former prod.exhaust: use explicit (case_tac t
   325 rule: prod.exhaust) here.
   326 
   327 * Attributes "cases", "induct", "coinduct" support "del" option.
   328 
   329 * Removed fact "case_split_thm", which duplicates "case_split".
   330 
   331 * The option datatype has been moved to a new theory Option.  Renamed
   332 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   333 
   334 * New predicate "strict_mono" classifies strict functions on partial
   335 orders.  With strict functions on linear orders, reasoning about
   336 (in)equalities is facilitated by theorems "strict_mono_eq",
   337 "strict_mono_less_eq" and "strict_mono_less".
   338 
   339 * Some set operations are now proper qualified constants with
   340 authentic syntax.  INCOMPATIBILITY:
   341 
   342     op Int ~>   Set.Int
   343     op Un ~>    Set.Un
   344     INTER ~>    Set.INTER
   345     UNION ~>    Set.UNION
   346     Inter ~>    Set.Inter
   347     Union ~>    Set.Union
   348     {} ~>       Set.empty
   349     UNIV ~>     Set.UNIV
   350 
   351 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   352 theory Set.
   353 
   354 * Auxiliary class "itself" has disappeared -- classes without any
   355 parameter are treated as expected by the 'class' command.
   356 
   357 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   358 
   359 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   360 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   361 
   362 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   363 method "approximation".  It proves formulas on real values by using
   364 interval arithmetic.  In the formulas are also the transcendental
   365 functions sin, cos, tan, atan, ln, exp and the constant pi are
   366 allowed. For examples see
   367 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   368 
   369 * Theory "Reflection" now resides in HOL/Library.
   370 
   371 * Entry point to Word library now simply named "Word".
   372 INCOMPATIBILITY.
   373 
   374 * Made source layout more coherent with logical distribution
   375 structure:
   376 
   377     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   378     src/HOL/Library/Code_Message.thy ~> src/HOL/
   379     src/HOL/Library/GCD.thy ~> src/HOL/
   380     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   381     src/HOL/Library/Parity.thy ~> src/HOL/
   382     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   383     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   384     src/HOL/Real/Lubs.thy ~> src/HOL/
   385     src/HOL/Real/PReal.thy ~> src/HOL/
   386     src/HOL/Real/Rational.thy ~> src/HOL/
   387     src/HOL/Real/RComplete.thy ~> src/HOL/
   388     src/HOL/Real/RealDef.thy ~> src/HOL/
   389     src/HOL/Real/RealPow.thy ~> src/HOL/
   390     src/HOL/Real/Real.thy ~> src/HOL/
   391     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   392     src/HOL/Complex/Complex.thy ~> src/HOL/
   393     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   394     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   395     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   396     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   397     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   398     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   399     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   400     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   401     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   402     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   403     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   404     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   405     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   406     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   407     src/HOL/Real/Float ~> src/HOL/Library/
   408     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   409     src/HOL/Real/RealVector.thy ~> src/HOL/
   410 
   411     src/HOL/arith_data.ML ~> src/HOL/Tools
   412     src/HOL/hologic.ML ~> src/HOL/Tools
   413     src/HOL/simpdata.ML ~> src/HOL/Tools
   414     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   415     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   416     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   417     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   418     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   419     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   420     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   421 
   422     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   423     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   424     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   425     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   426     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   427     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   428 
   429 * If methods "eval" and "evaluation" encounter a structured proof
   430 state with !!/==>, only the conclusion is evaluated to True (if
   431 possible), avoiding strange error messages.
   432 
   433 * Method "sizechange" automates termination proofs using (a
   434 modification of) the size-change principle.  Requires SAT solver.  See
   435 src/HOL/ex/Termination.thy for examples.
   436 
   437 * Simplifier: simproc for let expressions now unfolds if bound
   438 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   439 
   440 * Method "arith": Linear arithmetic now ignores all inequalities when
   441 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   442 
   443 * New attribute "arith" for facts that should always be used
   444 automatically by arithmetic. It is intended to be used locally in
   445 proofs, e.g.
   446 
   447   assumes [arith]: "x > 0"
   448 
   449 Global usage is discouraged because of possible performance impact.
   450 
   451 * New classes "top" and "bot" with corresponding operations "top" and
   452 "bot" in theory Orderings; instantiation of class "complete_lattice"
   453 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   454 
   455 * Changed definition lemma "less_fun_def" in order to provide an
   456 instance for preorders on functions; use lemma "less_le" instead.
   457 INCOMPATIBILITY.
   458 
   459 * Theory Orderings: class "wellorder" moved here, with explicit
   460 induction rule "less_induct" as assumption.  For instantiation of
   461 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   462 INCOMPATIBILITY.
   463 
   464 * Theory Orderings: added class "preorder" as superclass of "order".
   465 INCOMPATIBILITY: Instantiation proofs for order, linorder
   466 etc. slightly changed.  Some theorems named order_class.* now named
   467 preorder_class.*.
   468 
   469 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   470 "diag" to "Id_on".
   471 
   472 * Theory Finite_Set: added a new fold combinator of type
   473 
   474   ('a => 'b => 'b) => 'b => 'a set => 'b
   475 
   476 Occasionally this is more convenient than the old fold combinator
   477 which is now defined in terms of the new one and renamed to
   478 fold_image.
   479 
   480 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   481 and "ring_simps" have been replaced by "algebra_simps" (which can be
   482 extended with further lemmas!).  At the moment both still exist but
   483 the former will disappear at some point.
   484 
   485 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   486 class recpower.  Type-specific simp rules for various recpower types
   487 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   488 
   489 rat_power_0    -> power_0
   490 rat_power_Suc  -> power_Suc
   491 realpow_0      -> power_0
   492 realpow_Suc    -> power_Suc
   493 complexpow_0   -> power_0
   494 complexpow_Suc -> power_Suc
   495 power_poly_0   -> power_0
   496 power_poly_Suc -> power_Suc
   497 
   498 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   499 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   500 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   501 of lemmas from Divides has been generalized from nat to class
   502 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   503 renames resulting from duplicate elimination:
   504 
   505     dvd_def_mod ~>          dvd_eq_mod_eq_0
   506     zero_dvd_iff ~>         dvd_0_left_iff
   507     dvd_0 ~>                dvd_0_right
   508     DIVISION_BY_ZERO_DIV ~> div_by_0
   509     DIVISION_BY_ZERO_MOD ~> mod_by_0
   510     mult_div ~>             div_mult_self2_is_id
   511     mult_mod ~>             mod_mult_self2_is_0
   512 
   513 * Theory IntDiv: removed many lemmas that are instances of class-based
   514 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   515 rename old lemmas as follows:
   516 
   517 dvd_diff               -> nat_dvd_diff
   518 dvd_zminus_iff         -> dvd_minus_iff
   519 mod_add1_eq            -> mod_add_eq
   520 mod_mult1_eq           -> mod_mult_right_eq
   521 mod_mult1_eq'          -> mod_mult_left_eq
   522 mod_mult_distrib_mod   -> mod_mult_eq
   523 nat_mod_add_left_eq    -> mod_add_left_eq
   524 nat_mod_add_right_eq   -> mod_add_right_eq
   525 nat_mod_div_trivial    -> mod_div_trivial
   526 nat_mod_mod_trivial    -> mod_mod_trivial
   527 zdiv_zadd_self1        -> div_add_self1
   528 zdiv_zadd_self2        -> div_add_self2
   529 zdiv_zmult_self1       -> div_mult_self2_is_id
   530 zdiv_zmult_self2       -> div_mult_self1_is_id
   531 zdvd_triv_left         -> dvd_triv_left
   532 zdvd_triv_right        -> dvd_triv_right
   533 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   534 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   535 zmod_zadd_left_eq      -> mod_add_left_eq
   536 zmod_zadd_right_eq     -> mod_add_right_eq
   537 zmod_zadd_self1        -> mod_add_self1
   538 zmod_zadd_self2        -> mod_add_self2
   539 zmod_zadd1_eq          -> mod_add_eq
   540 zmod_zdiff1_eq         -> mod_diff_eq
   541 zmod_zdvd_zmod         -> mod_mod_cancel
   542 zmod_zmod_cancel       -> mod_mod_cancel
   543 zmod_zmult_self1       -> mod_mult_self2_is_0
   544 zmod_zmult_self2       -> mod_mult_self1_is_0
   545 zmod_1                 -> mod_by_1
   546 zdiv_1                 -> div_by_1
   547 zdvd_abs1              -> abs_dvd_iff
   548 zdvd_abs2              -> dvd_abs_iff
   549 zdvd_refl              -> dvd_refl
   550 zdvd_trans             -> dvd_trans
   551 zdvd_zadd              -> dvd_add
   552 zdvd_zdiff             -> dvd_diff
   553 zdvd_zminus_iff        -> dvd_minus_iff
   554 zdvd_zminus2_iff       -> minus_dvd_iff
   555 zdvd_zmultD            -> dvd_mult_right
   556 zdvd_zmultD2           -> dvd_mult_left
   557 zdvd_zmult_mono        -> mult_dvd_mono
   558 zdvd_0_right           -> dvd_0_right
   559 zdvd_0_left            -> dvd_0_left_iff
   560 zdvd_1_left            -> one_dvd
   561 zminus_dvd_iff         -> minus_dvd_iff
   562 
   563 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   564 
   565 * The real numbers offer decimal input syntax: 12.34 is translated
   566 into 1234/10^2. This translation is not reversed upon output.
   567 
   568 * Theory Library/Polynomial defines an abstract type 'a poly of
   569 univariate polynomials with coefficients of type 'a.  In addition to
   570 the standard ring operations, it also supports div and mod.  Code
   571 generation is also supported, using list-style constructors.
   572 
   573 * Theory Library/Inner_Product defines a class of real_inner for real
   574 inner product spaces, with an overloaded operation inner :: 'a => 'a
   575 => real.  Class real_inner is a subclass of real_normed_vector from
   576 theory RealVector.
   577 
   578 * Theory Library/Product_Vector provides instances for the product
   579 type 'a * 'b of several classes from RealVector and Inner_Product.
   580 Definitions of addition, subtraction, scalar multiplication, norms,
   581 and inner products are included.
   582 
   583 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   584 addition to the field operations, numerals and case syntax are also
   585 supported.
   586 
   587 * Theory Library/Diagonalize provides constructive version of Cantor's
   588 first diagonalization argument.
   589 
   590 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   591 zlcm (for int); carried together from various gcd/lcm developements in
   592 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   593 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   594 may recover tupled syntax as follows:
   595 
   596     hide (open) const gcd
   597     abbreviation gcd where
   598       "gcd == (%(a, b). GCD.gcd a b)"
   599     notation (output)
   600       GCD.gcd ("gcd '(_, _')")
   601 
   602 The same works for lcm, zgcd, zlcm.
   603 
   604 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   605 instantiations for algebraic structures.  Removed some duplicate
   606 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   607 
   608 * ML antiquotation @{code} takes a constant as argument and generates
   609 corresponding code in background and inserts name of the corresponding
   610 resulting ML value/function/datatype constructor binding in place.
   611 All occurrences of @{code} with a single ML block are generated
   612 simultaneously.  Provides a generic and safe interface for
   613 instrumentalizing code generation.  See
   614 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   615 In future you ought to refrain from ad-hoc compiling generated SML
   616 code on the ML toplevel.  Note that (for technical reasons) @{code}
   617 cannot refer to constants for which user-defined serializations are
   618 set.  Refer to the corresponding ML counterpart directly in that
   619 cases.
   620 
   621 * Command 'rep_datatype': instead of theorem names the command now
   622 takes a list of terms denoting the constructors of the type to be
   623 represented as datatype.  The characteristic theorems have to be
   624 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   625 have disappeared in favour of existing ones:
   626 
   627     unit_induct                 ~> unit.induct
   628     prod_induct                 ~> prod.induct
   629     sum_induct                  ~> sum.induct
   630     Suc_Suc_eq                  ~> nat.inject
   631     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   632 
   633 
   634 *** HOL-Algebra ***
   635 
   636 * New locales for orders and lattices where the equivalence relation
   637 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   638 locales use a record structure with field eq for the equivalence.
   639 
   640 * New theory of factorial domains.
   641 
   642 * Units_l_inv and Units_r_inv are now simp rules by default.
   643 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   644 and/or r_inv will now also require deletion of these lemmas.
   645 
   646 * Renamed the following theorems, INCOMPATIBILITY:
   647 
   648 UpperD ~> Upper_memD
   649 LowerD ~> Lower_memD
   650 least_carrier ~> least_closed
   651 greatest_carrier ~> greatest_closed
   652 greatest_Lower_above ~> greatest_Lower_below
   653 one_zero ~> carrier_one_zero
   654 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   655 
   656 
   657 *** HOL-Nominal ***
   658 
   659 * Nominal datatypes can now contain type-variables.
   660 
   661 * Commands 'nominal_inductive' and 'equivariance' work with local
   662 theory targets.
   663 
   664 * Nominal primrec can now works with local theory targets and its
   665 specification syntax now conforms to the general format as seen in
   666 'inductive' etc.
   667 
   668 * Method "perm_simp" honours the standard simplifier attributes
   669 (no_asm), (no_asm_use) etc.
   670 
   671 * The new predicate #* is defined like freshness, except that on the
   672 left hand side can be a set or list of atoms.
   673 
   674 * Experimental command 'nominal_inductive2' derives strong induction
   675 principles for inductive definitions.  In contrast to
   676 'nominal_inductive', which can only deal with a fixed number of
   677 binders, it can deal with arbitrary expressions standing for sets of
   678 atoms to be avoided.  The only inductive definition we have at the
   679 moment that needs this generalisation is the typing rule for Lets in
   680 the algorithm W:
   681 
   682  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   683  -----------------------------------------------------------------
   684          Gamma |- Let x be t1 in t2 : T2
   685 
   686 In this rule one wants to avoid all the binders that are introduced by
   687 "close Gamma T1".  We are looking for other examples where this
   688 feature might be useful.  Please let us know.
   689 
   690 
   691 *** HOLCF ***
   692 
   693 * Reimplemented the simplification procedure for proving continuity
   694 subgoals.  The new simproc is extensible; users can declare additional
   695 continuity introduction rules with the attribute [cont2cont].
   696 
   697 * The continuity simproc now uses a different introduction rule for
   698 solving continuity subgoals on terms with lambda abstractions.  In
   699 some rare cases the new simproc may fail to solve subgoals that the
   700 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   701 Potential INCOMPATIBILITY.
   702 
   703 * Command 'fixrec': specification syntax now conforms to the general
   704 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   705 examples.  INCOMPATIBILITY.
   706 
   707 
   708 *** ZF ***
   709 
   710 * Proof of Zorn's Lemma for partial orders.
   711 
   712 
   713 *** ML ***
   714 
   715 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   716 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   717 depends on multithreading, so timouts will not work before Poly/ML
   718 5.2.1!
   719 
   720 * High-level support for concurrent ML programming, see
   721 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   722 particularly convenient to organize independent functional
   723 computations.  The concept of "synchronized variables" provides a
   724 higher-order interface for components with shared state, avoiding the
   725 delicate details of mutexes and condition variables.  (Requires
   726 Poly/ML 5.2.1 or later.)
   727 
   728 * ML bindings produced via Isar commands are stored within the Isar
   729 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   730 become thread-safe and work with undo as expected (concerning
   731 top-level bindings, not side-effects on global references).
   732 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   733 compiler at runtime; really global bindings need to be given outside a
   734 theory.  (Requires Poly/ML 5.2 or later.)
   735 
   736 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   737 context.  Top-level ML bindings are stored within the proof context in
   738 a purely sequential fashion, disregarding the nested proof structure.
   739 ML bindings introduced by 'ML_prf' are discarded at the end of the
   740 proof.  (Requires Poly/ML 5.2 or later.)
   741 
   742 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   743 and Method.setup, as well as Isar commands 'attribute_setup' and
   744 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   745 existing code accordingly, or use plain 'setup' together with old
   746 Method.add_method.
   747 
   748 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   749 to 'a -> thm, while results are always tagged with an authentic oracle
   750 name.  The Isar command 'oracle' is now polymorphic, no argument type
   751 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   752 accordingly.  Note that extra performance may be gained by producing
   753 the cterm carefully, avoiding slow Thm.cterm_of.
   754 
   755 * Simplified interface for defining document antiquotations via
   756 ThyOutput.antiquotation, ThyOutput.output, and optionally
   757 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   758 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   759 examples.
   760 
   761 * More systematic treatment of long names, abstract name bindings, and
   762 name space operations.  Basic operations on qualified names have been
   763 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   764 Long_Name.append.  Old type bstring has been mostly replaced by
   765 abstract type binding (see structure Binding), which supports precise
   766 qualification by packages and local theory targets, as well as proper
   767 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   768 bstring values into Binding.name, or better pass through abstract
   769 bindings everywhere.  See further src/Pure/General/long_name.ML,
   770 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   771 
   772 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   773 LocalTheory.note etc.) now refer to the *full* internal name, not the
   774 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   775 
   776 * Disposed old type and term read functions (Sign.read_def_typ,
   777 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   778 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   779 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   780 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   781 resort for legacy applications.
   782 
   783 * Disposed old declarations, tactics, tactic combinators that refer to
   784 the simpset or claset of an implicit theory (such as Addsimps,
   785 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   786 embedded ML text, or local_simpset_of with a proper context passed as
   787 explicit runtime argument.
   788 
   789 * Rules and tactics that read instantiations (read_instantiate,
   790 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   791 context, which is required for parsing and type-checking.  Moreover,
   792 the variables are specified as plain indexnames, not string encodings
   793 thereof.  INCOMPATIBILITY.
   794 
   795 * Generic Toplevel.add_hook interface allows to analyze the result of
   796 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   797 for theorem dependency output of transactions resulting in a new
   798 theory state.
   799 
   800 * ML antiquotations: block-structured compilation context indicated by
   801 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   802 
   803   @{binding name}                         - basic name binding
   804   @{let ?pat = term}                      - term abbreviation (HO matching)
   805   @{note name = fact}                     - fact abbreviation
   806   @{thm fact}                             - singleton fact (with attributes)
   807   @{thms fact}                            - general fact (with attributes)
   808   @{lemma prop by method}                 - singleton goal
   809   @{lemma prop by meth1 meth2}            - singleton goal
   810   @{lemma prop1 ... propN by method}      - general goal
   811   @{lemma prop1 ... propN by meth1 meth2} - general goal
   812   @{lemma (open) ...}                     - open derivation
   813 
   814 
   815 *** System ***
   816 
   817 * The Isabelle "emacs" tool provides a specific interface to invoke
   818 Proof General / Emacs, with more explicit failure if that is not
   819 installed (the old isabelle-interface script silently falls back on
   820 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   821 installation location of the Proof General distribution.
   822 
   823 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   824 the Isabelle process into a JVM/Scala application.  See
   825 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   826 process wrapper has been discontinued.)
   827 
   828 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   829 
   830 * Various status messages (with exact source position information) are
   831 emitted, if proper markup print mode is enabled.  This allows
   832 user-interface components to provide detailed feedback on internal
   833 prover operations.
   834 
   835 
   836 
   837 New in Isabelle2008 (June 2008)
   838 -------------------------------
   839 
   840 *** General ***
   841 
   842 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   843 and updated, with formally checked references as hyperlinks.
   844 
   845 * Theory loader: use_thy (and similar operations) no longer set the
   846 implicit ML context, which was occasionally hard to predict and in
   847 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   848 provides a proper context already.
   849 
   850 * Theory loader: old-style ML proof scripts being *attached* to a thy
   851 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   852 'use' within a theory file will do the job.
   853 
   854 * Name space merge now observes canonical order, i.e. the second space
   855 is inserted into the first one, while existing entries in the first
   856 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   857 swap theory imports.
   858 
   859 * Syntax: symbol \<chi> is now considered a letter.  Potential
   860 INCOMPATIBILITY in identifier syntax etc.
   861 
   862 * Outer syntax: string tokens no longer admit escaped white space,
   863 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   864 white space without escapes.
   865 
   866 * Outer syntax: string tokens may contain arbitrary character codes
   867 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   868 "foo_bar".
   869 
   870 
   871 *** Pure ***
   872 
   873 * Context-dependent token translations.  Default setup reverts locally
   874 fixed variables, and adds hilite markup for undeclared frees.
   875 
   876 * Unused theorems can be found using the new command 'unused_thms'.
   877 There are three ways of invoking it:
   878 
   879 (1) unused_thms
   880      Only finds unused theorems in the current theory.
   881 
   882 (2) unused_thms thy_1 ... thy_n -
   883      Finds unused theorems in the current theory and all of its ancestors,
   884      excluding the theories thy_1 ... thy_n and all of their ancestors.
   885 
   886 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   887      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   888      their ancestors, excluding the theories thy_1 ... thy_n and all of
   889      their ancestors.
   890 
   891 In order to increase the readability of the list produced by
   892 unused_thms, theorems that have been created by a particular instance
   893 of a theory command such as 'inductive' or 'function' are considered
   894 to belong to the same "group", meaning that if at least one theorem in
   895 this group is used, the other theorems in the same group are no longer
   896 reported as unused.  Moreover, if all theorems in the group are
   897 unused, only one theorem in the group is displayed.
   898 
   899 Note that proof objects have to be switched on in order for
   900 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   901 usually the case when using Proof General with the default settings).
   902 
   903 * Authentic naming of facts disallows ad-hoc overwriting of previous
   904 theorems within the same name space.  INCOMPATIBILITY, need to remove
   905 duplicate fact bindings, or even accidental fact duplications.  Note
   906 that tools may maintain dynamically scoped facts systematically, using
   907 PureThy.add_thms_dynamic.
   908 
   909 * Command 'hide' now allows to hide from "fact" name space as well.
   910 
   911 * Eliminated destructive theorem database, simpset, claset, and
   912 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   913 update of theories within ML code.
   914 
   915 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   916 INCOMPATIBILITY, object-logics depending on former Pure require
   917 additional setup PureThy.old_appl_syntax_setup; object-logics
   918 depending on former CPure need to refer to Pure.
   919 
   920 * Commands 'use' and 'ML' are now purely functional, operating on
   921 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   922 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   923 INCOMPATIBILITY.
   924 
   925 * Command 'setup': discontinued implicit version with ML reference.
   926 
   927 * Instantiation target allows for simultaneous specification of class
   928 instance operations together with an instantiation proof.
   929 Type-checking phase allows to refer to class operations uniformly.
   930 See src/HOL/Complex/Complex.thy for an Isar example and
   931 src/HOL/Library/Eval.thy for an ML example.
   932 
   933 * Indexing of literal facts: be more serious about including only
   934 facts from the visible specification/proof context, but not the
   935 background context (locale etc.).  Affects `prop` notation and method
   936 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   937 situations.
   938 
   939 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   940 "(open)" option, which used to expose internal bound variables to the
   941 proof text.
   942 
   943 * Isar statements: removed obsolete case "rule_context".
   944 INCOMPATIBILITY, better use explicit fixes/assumes.
   945 
   946 * Locale proofs: default proof step now includes 'unfold_locales';
   947 hence 'proof' without argument may be used to unfold locale
   948 predicates.
   949 
   950 
   951 *** Document preparation ***
   952 
   953 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   954 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   955 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   956 spot); renamed link color from "darkblue" to "linkcolor" (default
   957 value unchanged, can be redefined via \definecolor); no longer sets
   958 "a4paper" option (unnecessary or even intrusive).
   959 
   960 * Antiquotation @{lemma A method} proves proposition A by the given
   961 method (either a method name or a method name plus (optional) method
   962 arguments in parentheses) and prints A just like @{prop A}.
   963 
   964 
   965 *** HOL ***
   966 
   967 * New primrec package.  Specification syntax conforms in style to
   968 definition/function/....  No separate induction rule is provided.  The
   969 "primrec" command distinguishes old-style and new-style specifications
   970 by syntax.  The former primrec package is now named OldPrimrecPackage.
   971 When adjusting theories, beware: constants stemming from new-style
   972 primrec specifications have authentic syntax.
   973 
   974 * Metis prover is now an order of magnitude faster, and also works
   975 with multithreading.
   976 
   977 * Metis: the maximum number of clauses that can be produced from a
   978 theorem is now given by the attribute max_clauses.  Theorems that
   979 exceed this number are ignored, with a warning printed.
   980 
   981 * Sledgehammer no longer produces structured proofs by default. To
   982 enable, declare [[sledgehammer_full = true]].  Attributes
   983 reconstruction_modulus, reconstruction_sorts renamed
   984 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   985 
   986 * Method "induct_scheme" derives user-specified induction rules
   987 from well-founded induction and completeness of patterns. This factors
   988 out some operations that are done internally by the function package
   989 and makes them available separately.  See
   990 src/HOL/ex/Induction_Scheme.thy for examples.
   991 
   992 * More flexible generation of measure functions for termination
   993 proofs: Measure functions can be declared by proving a rule of the
   994 form "is_measure f" and giving it the [measure_function] attribute.
   995 The "is_measure" predicate is logically meaningless (always true), and
   996 just guides the heuristic.  To find suitable measure functions, the
   997 termination prover sets up the goal "is_measure ?f" of the appropriate
   998 type and generates all solutions by prolog-style backwards proof using
   999 the declared rules.
  1000 
  1001 This setup also deals with rules like 
  1002 
  1003   "is_measure f ==> is_measure (list_size f)"
  1004 
  1005 which accommodates nested datatypes that recurse through lists.
  1006 Similar rules are predeclared for products and option types.
  1007 
  1008 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
  1009 
  1010   INCOMPATIBILITIES:
  1011 
  1012   - Definitions of overloaded constants on sets have to be replaced by
  1013     definitions on => and bool.
  1014 
  1015   - Some definitions of overloaded operators on sets can now be proved
  1016     using the definitions of the operators on => and bool.  Therefore,
  1017     the following theorems have been renamed:
  1018 
  1019       subset_def   -> subset_eq
  1020       psubset_def  -> psubset_eq
  1021       set_diff_def -> set_diff_eq
  1022       Compl_def    -> Compl_eq
  1023       Sup_set_def  -> Sup_set_eq
  1024       Inf_set_def  -> Inf_set_eq
  1025       sup_set_def  -> sup_set_eq
  1026       inf_set_def  -> inf_set_eq
  1027 
  1028   - Due to the incompleteness of the HO unification algorithm, some
  1029     rules such as subst may require manual instantiation, if some of
  1030     the unknowns in the rule is a set.
  1031 
  1032   - Higher order unification and forward proofs:
  1033     The proof pattern
  1034 
  1035       have "P (S::'a set)" <...>
  1036       then have "EX S. P S" ..
  1037 
  1038     no longer works (due to the incompleteness of the HO unification
  1039     algorithm) and must be replaced by the pattern
  1040 
  1041       have "EX S. P S"
  1042       proof
  1043         show "P S" <...>
  1044       qed
  1045 
  1046   - Calculational reasoning with subst (or similar rules):
  1047     The proof pattern
  1048 
  1049       have "P (S::'a set)" <...>
  1050       also have "S = T" <...>
  1051       finally have "P T" .
  1052 
  1053     no longer works (for similar reasons as the previous example) and
  1054     must be replaced by something like
  1055 
  1056       have "P (S::'a set)" <...>
  1057       moreover have "S = T" <...>
  1058       ultimately have "P T" by simp
  1059 
  1060   - Tactics or packages written in ML code:
  1061     Code performing pattern matching on types via
  1062 
  1063       Type ("set", [T]) => ...
  1064 
  1065     must be rewritten. Moreover, functions like strip_type or
  1066     binder_types no longer return the right value when applied to a
  1067     type of the form
  1068 
  1069       T1 => ... => Tn => U => bool
  1070 
  1071     rather than
  1072 
  1073       T1 => ... => Tn => U set
  1074 
  1075 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1076 Wellfounded_Relations to theory Wellfounded.
  1077 
  1078 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1079 
  1080 * Class finite no longer treats UNIV as class parameter.  Use class
  1081 enum from theory Library/Enum instead to achieve a similar effect.
  1082 INCOMPATIBILITY.
  1083 
  1084 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1085 and "Cons".  INCOMPATIBILITY.
  1086 
  1087 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1088 Potential INCOMPATIBILITY.
  1089 
  1090 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1091 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1092 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1093 
  1094 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1095 the same name in theory Orderings:
  1096 
  1097   less_trans
  1098   less_linear
  1099   le_imp_less_or_eq
  1100   le_less_trans
  1101   less_le_trans
  1102   less_not_sym
  1103   less_asym
  1104 
  1105 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1106 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1107 and different variable names.
  1108 
  1109 * Library/Option_ord.thy: Canonical order on option type.
  1110 
  1111 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1112 finite maps.
  1113 
  1114 * Library/Countable.thy: Type class for countable types.
  1115 
  1116 * Theory Int: The representation of numerals has changed.  The infix
  1117 operator BIT and the bit datatype with constructors B0 and B1 have
  1118 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1119 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1120 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1121 accordingly.
  1122 
  1123 * Theory Nat: definition of <= and < on natural numbers no longer
  1124 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1125 le_def and less_def have disappeared.  Consider lemmas not_less
  1126 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1127 
  1128 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1129 (whose purpose mainly is for various fold_set functionals) have been
  1130 abandoned in favor of the existing algebraic classes
  1131 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1132 lower_semilattice (resp. upper_semilattice) and linorder.
  1133 INCOMPATIBILITY.
  1134 
  1135 * Theory Transitive_Closure: induct and cases rules now declare proper
  1136 case_names ("base" and "step").  INCOMPATIBILITY.
  1137 
  1138 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1139 lattices.  The form set-specific version is available as
  1140 Inductive.lfp_ordinal_induct_set.
  1141 
  1142 * Renamed theorems "power.simps" to "power_int.simps".
  1143 INCOMPATIBILITY.
  1144 
  1145 * Class semiring_div provides basic abstract properties of semirings
  1146 with division and modulo operations.  Subsumes former class dvd_mod.
  1147 
  1148 * Merged theories IntDef, Numeral and IntArith into unified theory
  1149 Int.  INCOMPATIBILITY.
  1150 
  1151 * Theory Library/Code_Index: type "index" now represents natural
  1152 numbers rather than integers.  INCOMPATIBILITY.
  1153 
  1154 * New class "uminus" with operation "uminus" (split of from class
  1155 "minus" which now only has operation "minus", binary).
  1156 INCOMPATIBILITY.
  1157 
  1158 * Constants "card", "internal_split", "option_map" now with authentic
  1159 syntax.  INCOMPATIBILITY.
  1160 
  1161 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1162 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1163 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1164 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1165 Sup_set_def, le_def, less_def, option_map_def now with object
  1166 equality.  INCOMPATIBILITY.
  1167 
  1168 * Records. Removed K_record, and replaced it by pure lambda term
  1169 %x. c. The simplifier setup is now more robust against eta expansion.
  1170 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1171 
  1172 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1173 
  1174 * Library/ListVector: new theory of arithmetic vector operations.
  1175 
  1176 * Library/Order_Relation: new theory of various orderings as sets of
  1177 pairs.  Defines preorders, partial orders, linear orders and
  1178 well-orders on sets and on types.
  1179 
  1180 
  1181 *** ZF ***
  1182 
  1183 * Renamed some theories to allow to loading both ZF and HOL in the
  1184 same session:
  1185 
  1186   Datatype  -> Datatype_ZF
  1187   Inductive -> Inductive_ZF
  1188   Int       -> Int_ZF
  1189   IntDiv    -> IntDiv_ZF
  1190   Nat       -> Nat_ZF
  1191   List      -> List_ZF
  1192   Main      -> Main_ZF
  1193 
  1194 INCOMPATIBILITY: ZF theories that import individual theories below
  1195 Main might need to be adapted.  Regular theory Main is still
  1196 available, as trivial extension of Main_ZF.
  1197 
  1198 
  1199 *** ML ***
  1200 
  1201 * ML within Isar: antiquotation @{const name} or @{const
  1202 name(typargs)} produces statically-checked Const term.
  1203 
  1204 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1205 (of the same name).  Removed obsolete print command.
  1206 
  1207 * Removed obsolete "use_legacy_bindings" function.
  1208 
  1209 * The ``print mode'' is now a thread-local value derived from a global
  1210 template (the former print_mode reference), thus access becomes
  1211 non-critical.  The global print_mode reference is for session
  1212 management only; user-code should use print_mode_value,
  1213 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1214 
  1215 * Functions system/system_out provide a robust way to invoke external
  1216 shell commands, with propagation of interrupts (requires Poly/ML
  1217 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1218 
  1219 
  1220 *** System ***
  1221 
  1222 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1223 in accordance with Proof General 3.7, which prefers GNU emacs.
  1224 
  1225 * isatool tty runs Isabelle process with plain tty interaction;
  1226 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1227 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1228 
  1229 * isatool browser now works with Cygwin as well, using general
  1230 "javapath" function defined in Isabelle process environment.
  1231 
  1232 * YXML notation provides a simple and efficient alternative to
  1233 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1234 isatool yxml as described in the Isabelle system manual.
  1235 
  1236 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1237 provides general wrapper for managing an Isabelle process in a robust
  1238 fashion, with ``cooked'' output from stdin/stderr.
  1239 
  1240 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1241 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1242 
  1243 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1244 way of changing the user's settings is via
  1245 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1246 script.
  1247 
  1248 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1249 cores of the underlying machine, which is a good starting point for
  1250 optimal performance tuning.  The corresponding usedir option -M allows
  1251 "max" as an alias for "0".  WARNING: does not work on certain versions
  1252 of Mac OS (with Poly/ML 5.1).
  1253 
  1254 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1255 adverse effect of Isabelle flooding interactive front-ends (notably
  1256 ProofGeneral / XEmacs).
  1257 
  1258 
  1259 
  1260 New in Isabelle2007 (November 2007)
  1261 -----------------------------------
  1262 
  1263 *** General ***
  1264 
  1265 * More uniform information about legacy features, notably a
  1266 warning/error of "Legacy feature: ...", depending on the state of the
  1267 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1268 legacy features will disappear eventually.
  1269 
  1270 * Theory syntax: the header format ``theory A = B + C:'' has been
  1271 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1272 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1273 
  1274 * Theory syntax: the old non-Isar theory file format has been
  1275 discontinued altogether.  Note that ML proof scripts may still be used
  1276 with Isar theories; migration is usually quite simple with the ML
  1277 function use_legacy_bindings.  INCOMPATIBILITY.
  1278 
  1279 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1280 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1281 quotes.
  1282 
  1283 * Theory loader: be more serious about observing the static theory
  1284 header specifications (including optional directories), but not the
  1285 accidental file locations of previously successful loads.  The strict
  1286 update policy of former update_thy is now already performed by
  1287 use_thy, so the former has been removed; use_thys updates several
  1288 theories simultaneously, just as 'imports' within a theory header
  1289 specification, but without merging the results.  Potential
  1290 INCOMPATIBILITY: may need to refine theory headers and commands
  1291 ROOT.ML which depend on load order.
  1292 
  1293 * Theory loader: optional support for content-based file
  1294 identification, instead of the traditional scheme of full physical
  1295 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1296 (cf. the system manual).  The new scheme allows to work with
  1297 non-finished theories in persistent session images, such that source
  1298 files may be moved later on without requiring reloads.
  1299 
  1300 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1301 file (with the same base name as the theory) are considered a legacy
  1302 feature, which will disappear eventually. Even now, the theory loader
  1303 no longer maintains dependencies on such files.
  1304 
  1305 * Syntax: the scope for resolving ambiguities via type-inference is
  1306 now limited to individual terms, instead of whole simultaneous
  1307 specifications as before. This greatly reduces the complexity of the
  1308 syntax module and improves flexibility by separating parsing and
  1309 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1310 'fixes' etc.) are required in rare situations.
  1311 
  1312 * Syntax: constants introduced by new-style packages ('definition',
  1313 'abbreviation' etc.) are passed through the syntax module in
  1314 ``authentic mode''. This means that associated mixfix annotations
  1315 really stick to such constants, independently of potential name space
  1316 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1317 trees are represented slightly differently, may need to adapt syntax
  1318 translations accordingly. Use CONST marker in 'translations' and
  1319 @{const_syntax} antiquotation in 'parse_translation' etc.
  1320 
  1321 * Legacy goal package: reduced interface to the bare minimum required
  1322 to keep existing proof scripts running.  Most other user-level
  1323 functions are now part of the OldGoals structure, which is *not* open
  1324 by default (consider isatool expandshort before open OldGoals).
  1325 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1326 these tend to cause confusion about the actual goal (!) context being
  1327 used here, which is not necessarily the same as the_context().
  1328 
  1329 * Command 'find_theorems': supports "*" wild-card in "name:"
  1330 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1331 support a specific search form (see ProofGeneral/CHANGES).
  1332 
  1333 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1334 by default, which means that "prems" (and also "fixed variables") are
  1335 suppressed from proof state output.  Note that the ProofGeneral
  1336 settings mechanism allows to change and save options persistently, but
  1337 older versions of Isabelle will fail to start up if a negative prems
  1338 limit is imposed.
  1339 
  1340 * Local theory targets may be specified by non-nested blocks of
  1341 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1342 contain definitions, theorems etc., including any derived mechanism
  1343 that has been implemented on top of these primitives.  This concept
  1344 generalizes the existing ``theorem (in ...)'' towards more versatility
  1345 and scalability.
  1346 
  1347 * Proof General interface: proper undo of final 'end' command;
  1348 discontinued Isabelle/classic mode (ML proof scripts).
  1349 
  1350 
  1351 *** Document preparation ***
  1352 
  1353 * Added antiquotation @{theory name} which prints the given name,
  1354 after checking that it refers to a valid ancestor theory in the
  1355 current context.
  1356 
  1357 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1358 check the given source text as ML type/structure, printing verbatim.
  1359 
  1360 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1361 "c args == rhs" given in the current context.  (Any number of
  1362 arguments may be given on the LHS.)
  1363 
  1364 
  1365 *** Pure ***
  1366 
  1367 * The 'class' package offers a combination of axclass and locale to
  1368 achieve Haskell-like type classes in Isabelle.  Definitions and
  1369 theorems within a class context produce both relative results (with
  1370 implicit parameters according to the locale context), and polymorphic
  1371 constants with qualified polymorphism (according to the class
  1372 context).  Within the body context of a 'class' target, a separate
  1373 syntax layer ("user space type system") takes care of converting
  1374 between global polymorphic consts and internal locale representation.
  1375 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1376 "isatool doc classes" provides a tutorial.
  1377 
  1378 * Generic code generator framework allows to generate executable
  1379 code for ML and Haskell (including Isabelle classes).  A short usage
  1380 sketch:
  1381 
  1382     internal compilation:
  1383         export_code <list of constants (term syntax)> in SML
  1384     writing SML code to a file:
  1385         export_code <list of constants (term syntax)> in SML <filename>
  1386     writing OCaml code to a file:
  1387         export_code <list of constants (term syntax)> in OCaml <filename>
  1388     writing Haskell code to a bunch of files:
  1389         export_code <list of constants (term syntax)> in Haskell <filename>
  1390 
  1391     evaluating closed propositions to True/False using code generation:
  1392         method ``eval''
  1393 
  1394 Reasonable default setup of framework in HOL.
  1395 
  1396 Theorem attributs for selecting and transforming function equations theorems:
  1397 
  1398     [code fun]:        select a theorem as function equation for a specific constant
  1399     [code fun del]:    deselect a theorem as function equation for a specific constant
  1400     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1401     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1402 
  1403 User-defined serializations (target in {SML, OCaml, Haskell}):
  1404 
  1405     code_const <and-list of constants (term syntax)>
  1406       {(target) <and-list of const target syntax>}+
  1407 
  1408     code_type <and-list of type constructors>
  1409       {(target) <and-list of type target syntax>}+
  1410 
  1411     code_instance <and-list of instances>
  1412       {(target)}+
  1413         where instance ::= <type constructor> :: <class>
  1414 
  1415     code_class <and_list of classes>
  1416       {(target) <and-list of class target syntax>}+
  1417         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1418 
  1419 code_instance and code_class only are effective to target Haskell.
  1420 
  1421 For example usage see src/HOL/ex/Codegenerator.thy and
  1422 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1423 generation from Isabelle/HOL theories is available via "isatool doc
  1424 codegen".
  1425 
  1426 * Code generator: consts in 'consts_code' Isar commands are now
  1427 referred to by usual term syntax (including optional type
  1428 annotations).
  1429 
  1430 * Command 'no_translations' removes translation rules from theory
  1431 syntax.
  1432 
  1433 * Overloaded definitions are now actually checked for acyclic
  1434 dependencies.  The overloading scheme is slightly more general than
  1435 that of Haskell98, although Isabelle does not demand an exact
  1436 correspondence to type class and instance declarations.
  1437 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1438 exotic versions of overloading -- at the discretion of the user!
  1439 
  1440 Polymorphic constants are represented via type arguments, i.e. the
  1441 instantiation that matches an instance against the most general
  1442 declaration given in the signature.  For example, with the declaration
  1443 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1444 as c(nat).  Overloading is essentially simultaneous structural
  1445 recursion over such type arguments.  Incomplete specification patterns
  1446 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1447 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1448 Command 'print_theory' outputs the normalized system of recursive
  1449 equations, see section "definitions".
  1450 
  1451 * Configuration options are maintained within the theory or proof
  1452 context (with name and type bool/int/string), providing a very simple
  1453 interface to a poor-man's version of general context data.  Tools may
  1454 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1455 these values using Config.get etc.  Users may change options via an
  1456 associated attribute of the same name.  This form of context
  1457 declaration works particularly well with commands 'declare' or
  1458 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1459 very easy to avoid global references, which would not observe Isar
  1460 toplevel undo/redo and fail to work with multithreading.
  1461 
  1462 Various global ML references of Pure and HOL have been turned into
  1463 configuration options:
  1464 
  1465   Unify.search_bound		unify_search_bound
  1466   Unify.trace_bound		unify_trace_bound
  1467   Unify.trace_simp		unify_trace_simp
  1468   Unify.trace_types		unify_trace_types
  1469   Simplifier.simp_depth_limit	simp_depth_limit
  1470   Blast.depth_limit		blast_depth_limit
  1471   DatatypeProp.dtK		datatype_distinctness_limit
  1472   fast_arith_neq_limit  	fast_arith_neq_limit
  1473   fast_arith_split_limit	fast_arith_split_limit
  1474 
  1475 * Named collections of theorems may be easily installed as context
  1476 data using the functor NamedThmsFun (see also
  1477 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1478 attributes; there is also a toplevel print command.  This facility is
  1479 just a common case of general context data, which is the preferred way
  1480 for anything more complex than just a list of facts in canonical
  1481 order.
  1482 
  1483 * Isar: command 'declaration' augments a local theory by generic
  1484 declaration functions written in ML.  This enables arbitrary content
  1485 being added to the context, depending on a morphism that tells the
  1486 difference of the original declaration context wrt. the application
  1487 context encountered later on.
  1488 
  1489 * Isar: proper interfaces for simplification procedures.  Command
  1490 'simproc_setup' declares named simprocs (with match patterns, and body
  1491 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1492 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1493 
  1494 * Isar: an extra pair of brackets around attribute declarations
  1495 abbreviates a theorem reference involving an internal dummy fact,
  1496 which will be ignored later --- only the effect of the attribute on
  1497 the background context will persist.  This form of in-place
  1498 declarations is particularly useful with commands like 'declare' and
  1499 'using', for example ``have A using [[simproc a]] by simp''.
  1500 
  1501 * Isar: method "assumption" (and implicit closing of subproofs) now
  1502 takes simple non-atomic goal assumptions into account: after applying
  1503 an assumption as a rule the resulting subgoals are solved by atomic
  1504 assumption steps.  This is particularly useful to finish 'obtain'
  1505 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1506 without referring to the original premise "!!x. P x ==> thesis" in the
  1507 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1508 more permissive.
  1509 
  1510 * Isar: implicit use of prems from the Isar proof context is
  1511 considered a legacy feature.  Common applications like ``have A .''
  1512 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1513 referencing facts explicitly here improves readability and
  1514 maintainability of proof texts.
  1515 
  1516 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1517 the obtained context from the course of reasoning!  For example:
  1518 
  1519   assume "EX x y. A x & B y"   -- "any previous fact"
  1520   then guess x and y by clarify
  1521 
  1522 This technique is potentially adventurous, depending on the facts and
  1523 proof tools being involved here.
  1524 
  1525 * Isar: known facts from the proof context may be specified as literal
  1526 propositions, using ASCII back-quote syntax.  This works wherever
  1527 named facts used to be allowed so far, in proof commands, proof
  1528 methods, attributes etc.  Literal facts are retrieved from the context
  1529 according to unification of type and term parameters.  For example,
  1530 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1531 theorems in the current context, then these are valid literal facts:
  1532 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1533 
  1534 There is also a proof method "fact" which does the same composition
  1535 for explicit goal states, e.g. the following proof texts coincide with
  1536 certain special cases of literal facts:
  1537 
  1538   have "A" by fact                 ==  note `A`
  1539   have "A ==> B" by fact           ==  note `A ==> B`
  1540   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1541   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1542 
  1543 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1544 outer syntax.  Thus symbolic identifiers may be used without
  1545 additional white space in declarations like this: ``assume *: A''.
  1546 
  1547 * Isar: 'print_facts' prints all local facts of the current context,
  1548 both named and unnamed ones.
  1549 
  1550 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1551 
  1552   def x == "t" and y == "u"
  1553 
  1554 * Isar: added command 'unfolding', which is structurally similar to
  1555 'using', but affects both the goal state and facts by unfolding given
  1556 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1557 'unfolded' attribute may be replaced by first-class proof text.
  1558 
  1559 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1560 and command 'unfolding' now all support object-level equalities
  1561 (potentially conditional).  The underlying notion of rewrite rule is
  1562 analogous to the 'rule_format' attribute, but *not* that of the
  1563 Simplifier (which is usually more generous).
  1564 
  1565 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1566 premises of a theorem by n. Useful in conjunction with drule.
  1567 
  1568 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1569 method expression within a sandbox consisting of the first N
  1570 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1571 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1572 simplifies all new goals that emerge from applying rule foo to the
  1573 originally first one.
  1574 
  1575 * Isar: schematic goals are no longer restricted to higher-order
  1576 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1577 expected.
  1578 
  1579 * Isar: the conclusion of a long theorem statement is now either
  1580 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1581 (essentially a disjunction of cases with local parameters and
  1582 assumptions).  The latter allows to express general elimination rules
  1583 adequately; in this notation common elimination rules look like this:
  1584 
  1585   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1586     assumes "EX x. P x"
  1587     obtains x where "P x"
  1588 
  1589   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1590     assumes "A & B"
  1591     obtains A and B
  1592 
  1593   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1594     assumes "A | B"
  1595     obtains
  1596       A
  1597     | B
  1598 
  1599 The subsequent classical rules even refer to the formal "thesis"
  1600 explicitly:
  1601 
  1602   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1603     obtains "~ thesis"
  1604 
  1605   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1606     obtains "thesis ==> something"
  1607 
  1608 The actual proof of an 'obtains' statement is analogous to that of the
  1609 Isar proof element 'obtain', only that there may be several cases.
  1610 Optional case names may be specified in parentheses; these will be
  1611 available both in the present proof and as annotations in the
  1612 resulting rule, for later use with the 'cases' method (cf. attribute
  1613 case_names).
  1614 
  1615 * Isar: the assumptions of a long theorem statement are available as
  1616 "assms" fact in the proof context.  This is more appropriate than the
  1617 (historical) "prems", which refers to all assumptions of the current
  1618 context, including those from the target locale, proof body etc.
  1619 
  1620 * Isar: 'print_statement' prints theorems from the current theory or
  1621 proof context in long statement form, according to the syntax of a
  1622 top-level lemma.
  1623 
  1624 * Isar: 'obtain' takes an optional case name for the local context
  1625 introduction rule (default "that").
  1626 
  1627 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1628 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1629 to occur.
  1630 
  1631 * Pure: syntax "CONST name" produces a fully internalized constant
  1632 according to the current context.  This is particularly useful for
  1633 syntax translations that should refer to internal constant
  1634 representations independently of name spaces.
  1635 
  1636 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1637 instead of "FOO ". This allows multiple binder declarations to coexist
  1638 in the same context.  INCOMPATIBILITY.
  1639 
  1640 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1641 primitive that also works in a locale context (both for constants and
  1642 fixed variables). Type declaration and internal syntactic representation
  1643 of given constants retrieved from the context. Likewise, the
  1644 'no_notation' command allows to remove given syntax annotations from the
  1645 current context.
  1646 
  1647 * Isar/locales: new derived specification elements 'axiomatization',
  1648 'definition', 'abbreviation', which support type-inference, admit
  1649 object-level specifications (equality, equivalence).  See also the
  1650 isar-ref manual.  Examples:
  1651 
  1652   axiomatization
  1653     eq  (infix "===" 50) where
  1654     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1655 
  1656   definition "f x y = x + y + 1"
  1657   definition g where "g x = f x x"
  1658 
  1659   abbreviation
  1660     neq  (infix "=!=" 50) where
  1661     "x =!= y == ~ (x === y)"
  1662 
  1663 These specifications may be also used in a locale context.  Then the
  1664 constants being introduced depend on certain fixed parameters, and the
  1665 constant name is qualified by the locale base name.  An internal
  1666 abbreviation takes care for convenient input and output, making the
  1667 parameters implicit and using the original short name.  See also
  1668 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1669 entities from a monomorphic theory.
  1670 
  1671 Presently, abbreviations are only available 'in' a target locale, but
  1672 not inherited by general import expressions.  Also note that
  1673 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1674 'translations' in common applications.  The "no_abbrevs" print mode
  1675 prevents folding of abbreviations in term output.
  1676 
  1677 Concrete syntax is attached to specified constants in internal form,
  1678 independently of name spaces.  The parse tree representation is
  1679 slightly different -- use 'notation' instead of raw 'syntax', and
  1680 'translations' with explicit "CONST" markup to accommodate this.
  1681 
  1682 * Pure/Isar: unified syntax for new-style specification mechanisms
  1683 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1684 full type inference and dummy patterns ("_").  For example:
  1685 
  1686   definition "K x _ = x"
  1687 
  1688   inductive conj for A B
  1689   where "A ==> B ==> conj A B"
  1690 
  1691 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1692 the current context.  Print mode "no_abbrevs" prevents inversion of
  1693 abbreviations on output.
  1694 
  1695 * Isar/locales: improved parameter handling: use of locales "var" and
  1696 "struct" no longer necessary; - parameter renamings are no longer
  1697 required to be injective.  For example, this allows to define
  1698 endomorphisms as locale endom = homom mult mult h.
  1699 
  1700 * Isar/locales: changed the way locales with predicates are defined.
  1701 Instead of accumulating the specification, the imported expression is
  1702 now an interpretation.  INCOMPATIBILITY: different normal form of
  1703 locale expressions.  In particular, in interpretations of locales with
  1704 predicates, goals repesenting already interpreted fragments are not
  1705 removed automatically.  Use methods `intro_locales' and
  1706 `unfold_locales'; see below.
  1707 
  1708 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1709 provide backward reasoning on locales predicates.  The methods are
  1710 aware of interpretations and discharge corresponding goals.
  1711 `intro_locales' is less aggressive then `unfold_locales' and does not
  1712 unfold predicates to assumptions.
  1713 
  1714 * Isar/locales: the order in which locale fragments are accumulated
  1715 has changed.  This enables to override declarations from fragments due
  1716 to interpretations -- for example, unwanted simp rules.
  1717 
  1718 * Isar/locales: interpretation in theories and proof contexts has been
  1719 extended.  One may now specify (and prove) equations, which are
  1720 unfolded in interpreted theorems.  This is useful for replacing
  1721 defined concepts (constants depending on locale parameters) by
  1722 concepts already existing in the target context.  Example:
  1723 
  1724   interpretation partial_order ["op <= :: [int, int] => bool"]
  1725     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1726 
  1727 Typically, the constant `partial_order.less' is created by a
  1728 definition specification element in the context of locale
  1729 partial_order.
  1730 
  1731 * Method "induct": improved internal context management to support
  1732 local fixes and defines on-the-fly. Thus explicit meta-level
  1733 connectives !!  and ==> are rarely required anymore in inductive goals
  1734 (using object-logic connectives for this purpose has been long
  1735 obsolete anyway). Common proof patterns are explained in
  1736 src/HOL/Induct/Common_Patterns.thy, see also
  1737 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1738 examples.
  1739 
  1740 * Method "induct": improved handling of simultaneous goals. Instead of
  1741 introducing object-level conjunction, the statement is now split into
  1742 several conclusions, while the corresponding symbolic cases are nested
  1743 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1744 see src/HOL/Induct/Common_Patterns.thy, for example.
  1745 
  1746 * Method "induct": mutual induction rules are now specified as a list
  1747 of rule sharing the same induction cases. HOL packages usually provide
  1748 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1749 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1750 mutual induction rules differently, i.e. like this:
  1751 
  1752   (induct rule: foo_bar.inducts)
  1753   (induct set: foo bar)
  1754   (induct pred: foo bar)
  1755   (induct type: foo bar)
  1756 
  1757 The ML function ProjectRule.projections turns old-style rules into the
  1758 new format.
  1759 
  1760 * Method "coinduct": dual of induction, see
  1761 src/HOL/Library/Coinductive_List.thy for various examples.
  1762 
  1763 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1764 considered a legacy feature.
  1765 
  1766 * Attribute "symmetric" produces result with standardized schematic
  1767 variables (index 0).  Potential INCOMPATIBILITY.
  1768 
  1769 * Simplifier: by default the simplifier trace only shows top level
  1770 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1771 default. Thus there is less danger of being flooded by the trace. The
  1772 trace indicates where parts have been suppressed.
  1773   
  1774 * Provers/classical: removed obsolete classical version of elim_format
  1775 attribute; classical elim/dest rules are now treated uniformly when
  1776 manipulating the claset.
  1777 
  1778 * Provers/classical: stricter checks to ensure that supplied intro,
  1779 dest and elim rules are well-formed; dest and elim rules must have at
  1780 least one premise.
  1781 
  1782 * Provers/classical: attributes dest/elim/intro take an optional
  1783 weight argument for the rule (just as the Pure versions).  Weights are
  1784 ignored by automated tools, but determine the search order of single
  1785 rule steps.
  1786 
  1787 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1788 where the body does not mention the bound variable.  Note that dummy
  1789 patterns implicitly depend on their context of bounds, which makes
  1790 "{_. _}" match any set comprehension as expected.  Potential
  1791 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1792 constant "_idtdummy" in the binding position.
  1793 
  1794 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1795 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1796 for example "A -> B" => "Pi A (%_. B)".
  1797 
  1798 * Pure: 'class_deps' command visualizes the subclass relation, using
  1799 the graph browser tool.
  1800 
  1801 * Pure: 'print_theory' now suppresses certain internal declarations by
  1802 default; use '!' option for full details.
  1803 
  1804 
  1805 *** HOL ***
  1806 
  1807 * Method "metis" proves goals by applying the Metis general-purpose
  1808 resolution prover (see also http://gilith.com/software/metis/).
  1809 Examples are in the directory MetisExamples.  WARNING: the
  1810 Isabelle/HOL-Metis integration does not yet work properly with
  1811 multi-threading.
  1812   
  1813 * Command 'sledgehammer' invokes external automatic theorem provers as
  1814 background processes.  It generates calls to the "metis" method if
  1815 successful. These can be pasted into the proof.  Users do not have to
  1816 wait for the automatic provers to return.  WARNING: does not really
  1817 work with multi-threading.
  1818 
  1819 * New "auto_quickcheck" feature tests outermost goal statements for
  1820 potential counter-examples.  Controlled by ML references
  1821 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1822 5000 milliseconds).  Fails silently if statements is outside of
  1823 executable fragment, or any other codgenerator problem occurs.
  1824 
  1825 * New constant "undefined" with axiom "undefined x = undefined".
  1826 
  1827 * Added class "HOL.eq", allowing for code generation with polymorphic
  1828 equality.
  1829 
  1830 * Some renaming of class constants due to canonical name prefixing in
  1831 the new 'class' package:
  1832 
  1833     HOL.abs ~> HOL.abs_class.abs
  1834     HOL.divide ~> HOL.divide_class.divide
  1835     0 ~> HOL.zero_class.zero
  1836     1 ~> HOL.one_class.one
  1837     op + ~> HOL.plus_class.plus
  1838     op - ~> HOL.minus_class.minus
  1839     uminus ~> HOL.minus_class.uminus
  1840     op * ~> HOL.times_class.times
  1841     op < ~> HOL.ord_class.less
  1842     op <= > HOL.ord_class.less_eq
  1843     Nat.power ~> Power.power_class.power
  1844     Nat.size ~> Nat.size_class.size
  1845     Numeral.number_of ~> Numeral.number_class.number_of
  1846     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1847     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1848     Orderings.min ~> Orderings.ord_class.min
  1849     Orderings.max ~> Orderings.ord_class.max
  1850     Divides.op div ~> Divides.div_class.div
  1851     Divides.op mod ~> Divides.div_class.mod
  1852     Divides.op dvd ~> Divides.div_class.dvd
  1853 
  1854 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1855 
  1856 a) User-defined constants using any of the names "plus", "minus",
  1857 "times", "less" or "less_eq". The standard syntax translations for
  1858 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1859 names.
  1860 
  1861 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1862 INCOMPATIBILITY: use more specific names.
  1863 
  1864 c) Permutative equations (e.g. "a + b = b + a")
  1865 Since the change of names also changes the order of terms, permutative
  1866 rewrite rules may get applied in a different order. Experience shows
  1867 that this is rarely the case (only two adaptions in the whole Isabelle
  1868 distribution).  INCOMPATIBILITY: rewrite proofs
  1869 
  1870 d) ML code directly refering to constant names
  1871 This in general only affects hand-written proof tactics, simprocs and
  1872 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1873 Consider using @{const_name} antiquotation.
  1874 
  1875 * New class "default" with associated constant "default".
  1876 
  1877 * Function "sgn" is now overloaded and available on int, real, complex
  1878 (and other numeric types), using class "sgn".  Two possible defs of
  1879 sgn are given as equational assumptions in the classes sgn_if and
  1880 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1881 INCOMPATIBILITY.
  1882 
  1883 * Locale "partial_order" now unified with class "order" (cf. theory
  1884 Orderings), added parameter "less".  INCOMPATIBILITY.
  1885 
  1886 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1887 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1888 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1889 
  1890 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1891 changed order of proof goals in instance proofs.
  1892 
  1893 * The transitivity reasoner for partial and linear orders is set up
  1894 for classes "order" and "linorder".  Instances of the reasoner are available
  1895 in all contexts importing or interpreting the corresponding locales.
  1896 Method "order" invokes the reasoner separately; the reasoner
  1897 is also integrated with the Simplifier as a solver.  Diagnostic
  1898 command 'print_orders' shows the available instances of the reasoner
  1899 in the current context.
  1900 
  1901 * Localized monotonicity predicate in theory "Orderings"; integrated
  1902 lemmas max_of_mono and min_of_mono with this predicate.
  1903 INCOMPATIBILITY.
  1904 
  1905 * Formulation of theorem "dense" changed slightly due to integration
  1906 with new class dense_linear_order.
  1907 
  1908 * Uniform lattice theory development in HOL.
  1909 
  1910     constants "meet" and "join" now named "inf" and "sup"
  1911     constant "Meet" now named "Inf"
  1912 
  1913     classes "meet_semilorder" and "join_semilorder" now named
  1914       "lower_semilattice" and "upper_semilattice"
  1915     class "lorder" now named "lattice"
  1916     class "comp_lat" now named "complete_lattice"
  1917 
  1918     Instantiation of lattice classes allows explicit definitions
  1919     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1920 
  1921   INCOMPATIBILITY.  Theorem renames:
  1922 
  1923     meet_left_le            ~> inf_le1
  1924     meet_right_le           ~> inf_le2
  1925     join_left_le            ~> sup_ge1
  1926     join_right_le           ~> sup_ge2
  1927     meet_join_le            ~> inf_sup_ord
  1928     le_meetI                ~> le_infI
  1929     join_leI                ~> le_supI
  1930     le_meet                 ~> le_inf_iff
  1931     le_join                 ~> ge_sup_conv
  1932     meet_idempotent         ~> inf_idem
  1933     join_idempotent         ~> sup_idem
  1934     meet_comm               ~> inf_commute
  1935     join_comm               ~> sup_commute
  1936     meet_leI1               ~> le_infI1
  1937     meet_leI2               ~> le_infI2
  1938     le_joinI1               ~> le_supI1
  1939     le_joinI2               ~> le_supI2
  1940     meet_assoc              ~> inf_assoc
  1941     join_assoc              ~> sup_assoc
  1942     meet_left_comm          ~> inf_left_commute
  1943     meet_left_idempotent    ~> inf_left_idem
  1944     join_left_comm          ~> sup_left_commute
  1945     join_left_idempotent    ~> sup_left_idem
  1946     meet_aci                ~> inf_aci
  1947     join_aci                ~> sup_aci
  1948     le_def_meet             ~> le_iff_inf
  1949     le_def_join             ~> le_iff_sup
  1950     join_absorp2            ~> sup_absorb2
  1951     join_absorp1            ~> sup_absorb1
  1952     meet_absorp1            ~> inf_absorb1
  1953     meet_absorp2            ~> inf_absorb2
  1954     meet_join_absorp        ~> inf_sup_absorb
  1955     join_meet_absorp        ~> sup_inf_absorb
  1956     distrib_join_le         ~> distrib_sup_le
  1957     distrib_meet_le         ~> distrib_inf_le
  1958 
  1959     add_meet_distrib_left   ~> add_inf_distrib_left
  1960     add_join_distrib_left   ~> add_sup_distrib_left
  1961     is_join_neg_meet        ~> is_join_neg_inf
  1962     is_meet_neg_join        ~> is_meet_neg_sup
  1963     add_meet_distrib_right  ~> add_inf_distrib_right
  1964     add_join_distrib_right  ~> add_sup_distrib_right
  1965     add_meet_join_distribs  ~> add_sup_inf_distribs
  1966     join_eq_neg_meet        ~> sup_eq_neg_inf
  1967     meet_eq_neg_join        ~> inf_eq_neg_sup
  1968     add_eq_meet_join        ~> add_eq_inf_sup
  1969     meet_0_imp_0            ~> inf_0_imp_0
  1970     join_0_imp_0            ~> sup_0_imp_0
  1971     meet_0_eq_0             ~> inf_0_eq_0
  1972     join_0_eq_0             ~> sup_0_eq_0
  1973     neg_meet_eq_join        ~> neg_inf_eq_sup
  1974     neg_join_eq_meet        ~> neg_sup_eq_inf
  1975     join_eq_if              ~> sup_eq_if
  1976 
  1977     mono_meet               ~> mono_inf
  1978     mono_join               ~> mono_sup
  1979     meet_bool_eq            ~> inf_bool_eq
  1980     join_bool_eq            ~> sup_bool_eq
  1981     meet_fun_eq             ~> inf_fun_eq
  1982     join_fun_eq             ~> sup_fun_eq
  1983     meet_set_eq             ~> inf_set_eq
  1984     join_set_eq             ~> sup_set_eq
  1985     meet1_iff               ~> inf1_iff
  1986     meet2_iff               ~> inf2_iff
  1987     meet1I                  ~> inf1I
  1988     meet2I                  ~> inf2I
  1989     meet1D1                 ~> inf1D1
  1990     meet2D1                 ~> inf2D1
  1991     meet1D2                 ~> inf1D2
  1992     meet2D2                 ~> inf2D2
  1993     meet1E                  ~> inf1E
  1994     meet2E                  ~> inf2E
  1995     join1_iff               ~> sup1_iff
  1996     join2_iff               ~> sup2_iff
  1997     join1I1                 ~> sup1I1
  1998     join2I1                 ~> sup2I1
  1999     join1I1                 ~> sup1I1
  2000     join2I2                 ~> sup1I2
  2001     join1CI                 ~> sup1CI
  2002     join2CI                 ~> sup2CI
  2003     join1E                  ~> sup1E
  2004     join2E                  ~> sup2E
  2005 
  2006     is_meet_Meet            ~> is_meet_Inf
  2007     Meet_bool_def           ~> Inf_bool_def
  2008     Meet_fun_def            ~> Inf_fun_def
  2009     Meet_greatest           ~> Inf_greatest
  2010     Meet_lower              ~> Inf_lower
  2011     Meet_set_def            ~> Inf_set_def
  2012 
  2013     Sup_def                 ~> Sup_Inf
  2014     Sup_bool_eq             ~> Sup_bool_def
  2015     Sup_fun_eq              ~> Sup_fun_def
  2016     Sup_set_eq              ~> Sup_set_def
  2017 
  2018     listsp_meetI            ~> listsp_infI
  2019     listsp_meet_eq          ~> listsp_inf_eq
  2020 
  2021     meet_min                ~> inf_min
  2022     join_max                ~> sup_max
  2023 
  2024 * Added syntactic class "size"; overloaded constant "size" now has
  2025 type "'a::size ==> bool"
  2026 
  2027 * Internal reorganisation of `size' of datatypes: size theorems
  2028 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2029 simplification rules by default!); theorems "prod.size" now named
  2030 "*.size".
  2031 
  2032 * Class "div" now inherits from class "times" rather than "type".
  2033 INCOMPATIBILITY.
  2034 
  2035 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2036 Linorder etc.  have disappeared; operations defined in terms of
  2037 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2038 
  2039 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2040 
  2041 * HOL-Word: New extensive library and type for generic, fixed size
  2042 machine words, with arithemtic, bit-wise, shifting and rotating
  2043 operations, reflection into int, nat, and bool lists, automation for
  2044 linear arithmetic (by automatic reflection into nat or int), including
  2045 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2046 arithmetic type classes, supporting automatic simplification of
  2047 numerals on all operations.
  2048 
  2049 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2050 
  2051 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2052 
  2053 * Code generator library theories:
  2054   - Code_Integer represents HOL integers by big integer literals in target
  2055     languages.
  2056   - Code_Char represents HOL characters by character literals in target
  2057     languages.
  2058   - Code_Char_chr like Code_Char, but also offers treatment of character
  2059     codes; includes Code_Integer.
  2060   - Executable_Set allows to generate code for finite sets using lists.
  2061   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2062     denominator).
  2063   - Executable_Real implements a subset of real numbers, namly those
  2064     representable by rational numbers.
  2065   - Efficient_Nat implements natural numbers by integers, which in general will
  2066     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2067     includes Code_Integer.
  2068   - Code_Index provides an additional datatype index which is mapped to
  2069     target-language built-in integers.
  2070   - Code_Message provides an additional datatype message_string which is isomorphic to
  2071     strings; messages are mapped to target-language strings.
  2072 
  2073 * New package for inductive predicates
  2074 
  2075   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2076 
  2077     inductive
  2078       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2079       for z_1 :: U_1 and ... and z_n :: U_m
  2080     where
  2081       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2082     | ...
  2083 
  2084   with full support for type-inference, rather than
  2085 
  2086     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2087 
  2088     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2089     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2090 
  2091     inductive "s z_1 ... z_m"
  2092     intros
  2093       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2094       ...
  2095 
  2096   For backward compatibility, there is a wrapper allowing inductive
  2097   sets to be defined with the new package via
  2098 
  2099     inductive_set
  2100       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2101       for z_1 :: U_1 and ... and z_n :: U_m
  2102     where
  2103       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2104     | ...
  2105 
  2106   or
  2107 
  2108     inductive_set
  2109       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2110       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2111       for z_1 :: U_1 and ... and z_n :: U_m
  2112     where
  2113       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2114     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2115     | ...
  2116 
  2117   if the additional syntax "p ..." is required.
  2118 
  2119   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2120   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2121 
  2122   INCOMPATIBILITIES:
  2123 
  2124   - Since declaration and definition of inductive sets or predicates
  2125     is no longer separated, abbreviations involving the newly
  2126     introduced sets or predicates must be specified together with the
  2127     introduction rules after the 'where' keyword (see above), rather
  2128     than before the actual inductive definition.
  2129 
  2130   - The variables in induction and elimination rules are now
  2131     quantified in the order of their occurrence in the introduction
  2132     rules, rather than in alphabetical order. Since this may break
  2133     some proofs, these proofs either have to be repaired, e.g. by
  2134     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2135     statements of the form
  2136 
  2137       case (rule_i a_i_1 ... a_i_{k_i})
  2138 
  2139     or the old order of quantification has to be restored by explicitly adding
  2140     meta-level quantifiers in the introduction rules, i.e.
  2141 
  2142       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2143 
  2144   - The format of the elimination rules is now
  2145 
  2146       p z_1 ... z_m x_1 ... x_n ==>
  2147         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2148         ==> ... ==> P
  2149 
  2150     for predicates and
  2151 
  2152       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2153         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2154         ==> ... ==> P
  2155 
  2156     for sets rather than
  2157 
  2158       x : s z_1 ... z_m ==>
  2159         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2160         ==> ... ==> P
  2161 
  2162     This may require terms in goals to be expanded to n-tuples
  2163     (e.g. using case_tac or simplification with the split_paired_all
  2164     rule) before the above elimination rule is applicable.
  2165 
  2166   - The elimination or case analysis rules for (mutually) inductive
  2167     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2168     list of rules "p_1_..._p_k.elims" is no longer available.
  2169 
  2170 * New package "function"/"fun" for general recursive functions,
  2171 supporting mutual and nested recursion, definitions in local contexts,
  2172 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2173 for small examples, and the separate tutorial on the function
  2174 package. The old recdef "package" is still available as before, but
  2175 users are encouraged to use the new package.
  2176 
  2177 * Method "lexicographic_order" automatically synthesizes termination
  2178 relations as lexicographic combinations of size measures. 
  2179 
  2180 * Case-expressions allow arbitrary constructor-patterns (including
  2181 "_") and take their order into account, like in functional
  2182 programming.  Internally, this is translated into nested
  2183 case-expressions; missing cases are added and mapped to the predefined
  2184 constant "undefined". In complicated cases printing may no longer show
  2185 the original input but the internal form. Lambda-abstractions allow
  2186 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2187 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2188 variable.
  2189 
  2190 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2191 is an abbreviation for "of_nat :: nat => int". The simplification
  2192 rules for "of_nat" have been changed to work like "int" did
  2193 previously.  Potential INCOMPATIBILITY:
  2194   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2195   - of_nat_diff and of_nat_mult are no longer default simp rules
  2196 
  2197 * Method "algebra" solves polynomial equations over (semi)rings using
  2198 Groebner bases. The (semi)ring structure is defined by locales and the
  2199 tool setup depends on that generic context. Installing the method for
  2200 a specific type involves instantiating the locale and possibly adding
  2201 declarations for computation on the coefficients.  The method is
  2202 already instantiated for natural numbers and for the axiomatic class
  2203 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2204 CALCULEMUS 2007 for the general principles underlying this
  2205 architecture of context-aware proof-tools.
  2206 
  2207 * Method "ferrack" implements quantifier elimination over
  2208 special-purpose dense linear orders using locales (analogous to
  2209 "algebra"). The method is already installed for class
  2210 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2211 rat, etc.
  2212 
  2213 * Former constant "List.op @" now named "List.append".  Use ML
  2214 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2215 circumvent possible incompatibilities when working on ML level.
  2216 
  2217 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2218 
  2219 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2220 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2221 
  2222 * New syntax for Haskell-like list comprehension (input only), eg.
  2223 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2224 
  2225 * The special syntax for function "filter" has changed from [x :
  2226 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2227 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2228 
  2229 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2230 defined on nat only, as an abbreviation for [a..<Suc b]
  2231 INCOMPATIBILITY.
  2232 
  2233 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2234 
  2235 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2236 
  2237 * New lemma collection field_simps (an extension of ring_simps) for
  2238 manipulating (in)equations involving division. Multiplies with all
  2239 denominators that can be proved to be non-zero (in equations) or
  2240 positive/negative (in inequations).
  2241 
  2242 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2243 have been improved and renamed to ring_simps, group_simps and
  2244 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2245 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2246 
  2247 * Theory Library/Commutative_Ring: switched from recdef to function
  2248 package; constants add, mul, pow now curried.  Infix syntax for
  2249 algebraic operations.
  2250 
  2251 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2252 INCOMPATIBILITY.
  2253 
  2254 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2255 INCOMPATIBILITY.
  2256 
  2257 * HOL/records: generalised field-update to take a function on the
  2258 field rather than the new value: r(|A := x|) is translated to A_update
  2259 (K x) r The K-combinator that is internally used is called K_record.
  2260 INCOMPATIBILITY: Usage of the plain update functions has to be
  2261 adapted.
  2262  
  2263 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2264 * x = 0, which are required for a semiring.  Richer structures do not
  2265 inherit from semiring_0 anymore, because this property is a theorem
  2266 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2267 there is more to prove, but this is mostly trivial.
  2268 
  2269 * Class "recpower" is generalized to arbitrary monoids, not just
  2270 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2271 commutativity or semiring properties additionally.
  2272 
  2273 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2274 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2275 better use 'abbreviation'.
  2276 
  2277 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2278 
  2279 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2280 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2281 significant changes for setting up numeral syntax for types:
  2282   - New constants Numeral.pred and Numeral.succ instead
  2283       of former Numeral.bin_pred and Numeral.bin_succ.
  2284   - Use integer operations instead of bin_add, bin_mult and so on.
  2285   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2286   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2287 
  2288 See src/HOL/Integ/IntArith.thy for an example setup.
  2289 
  2290 * Command 'normal_form' computes the normal form of a term that may
  2291 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2292 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2293 heavy-duty computations because the functions are compiled to ML
  2294 first.  Correspondingly, a method "normalization" is provided.  See
  2295 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2296 
  2297 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2298 25 like -->); output depends on the "iff" print_mode, the default is
  2299 "A = B" (with priority 50).
  2300 
  2301 * Relations less (<) and less_eq (<=) are also available on type bool.
  2302 Modified syntax to disallow nesting without explicit parentheses,
  2303 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2304 INCOMPATIBILITY.
  2305 
  2306 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2307 
  2308 * Relation composition operator "op O" now has precedence 75 and binds
  2309 stronger than union and intersection. INCOMPATIBILITY.
  2310 
  2311 * The old set interval syntax "{m..n(}" (and relatives) has been
  2312 removed.  Use "{m..<n}" (and relatives) instead.
  2313 
  2314 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2315 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2316 ``declare [[simproc del: neq]]''.
  2317 
  2318 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2319 True/False.
  2320 
  2321 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2322 
  2323 * Theorem setsum_mult renamed to setsum_right_distrib.
  2324 
  2325 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2326 ``rule'' method.
  2327 
  2328 * Reimplemented methods "sat" and "satx", with several improvements:
  2329 goals no longer need to be stated as "<prems> ==> False", equivalences
  2330 (i.e. "=" on type bool) are handled, variable names of the form
  2331 "lit_<n>" are no longer reserved, significant speedup.
  2332 
  2333 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2334 zChaff is still supported as well.
  2335 
  2336 * 'inductive' and 'datatype': provide projections of mutual rules,
  2337 bundled as foo_bar.inducts;
  2338 
  2339 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2340 Library.
  2341 
  2342 * Library: moved theory Accessible_Part to main HOL.
  2343 
  2344 * Library: added theory Coinductive_List of potentially infinite lists
  2345 as greatest fixed-point.
  2346 
  2347 * Library: added theory AssocList which implements (finite) maps as
  2348 association lists.
  2349 
  2350 * Method "evaluation" solves goals (i.e. a boolean expression)
  2351 efficiently by compiling it to ML.  The goal is "proved" (via an
  2352 oracle) if it evaluates to True.
  2353 
  2354 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2355 also when invoked by the simplifier.  This results in the Simplifier
  2356 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2357 Configuration option fast_arith_split_limit=0 recovers the old
  2358 behavior.
  2359 
  2360 * Support for hex (0x20) and binary (0b1001) numerals.
  2361 
  2362 * New method: reify eqs (t), where eqs are equations for an
  2363 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2364 parameter, computes a term s::'b and a list xs::'a list and proves the
  2365 theorem I xs s = t. This is also known as reification or quoting. The
  2366 resulting theorem is applied to the subgoal to substitute t with I xs
  2367 s.  If t is omitted, the subgoal itself is reified.
  2368 
  2369 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2370 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2371 where f is supposed to be a computable function (in the sense of code
  2372 generattion). The method uses reify to compute s and xs as above then
  2373 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2374 r and finally gets the theorem t = r, which is again applied to the
  2375 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2376 
  2377 * Reflection: Automatic reification now handels binding, an example is
  2378 available in src/HOL/ex/ReflectionEx.thy
  2379 
  2380 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2381 command 'statespace' that is similar to 'record', but introduces an
  2382 abstract specification based on the locale infrastructure instead of
  2383 HOL types.  This leads to extra flexibility in composing state spaces,
  2384 in particular multiple inheritance and renaming of components.
  2385 
  2386 
  2387 *** HOL-Complex ***
  2388 
  2389 * Hyperreal: Functions root and sqrt are now defined on negative real
  2390 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2391 Nonnegativity side conditions have been removed from many lemmas, so
  2392 that more subgoals may now be solved by simplification; potential
  2393 INCOMPATIBILITY.
  2394 
  2395 * Real: new type classes formalize real normed vector spaces and
  2396 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2397 and norm :: 'a => real.
  2398 
  2399 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2400 reals into other types. The overloaded constant Reals :: 'a set is now
  2401 defined as range of_real; potential INCOMPATIBILITY.
  2402 
  2403 * Real: proper support for ML code generation, including 'quickcheck'.
  2404 Reals are implemented as arbitrary precision rationals.
  2405 
  2406 * Hyperreal: Several constants that previously worked only for the
  2407 reals have been generalized, so they now work over arbitrary vector
  2408 spaces. Type annotations may need to be added in some cases; potential
  2409 INCOMPATIBILITY.
  2410 
  2411   Infinitesimal  :: ('a::real_normed_vector) star set
  2412   HFinite        :: ('a::real_normed_vector) star set
  2413   HInfinite      :: ('a::real_normed_vector) star set
  2414   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2415   monad          :: ('a::real_normed_vector) star => 'a star set
  2416   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2417   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2418   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2419   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2420   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2421   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2422   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2423   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2424   sgn            :: 'a::real_normed_vector => 'a
  2425   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2426 
  2427 * Complex: Some complex-specific constants are now abbreviations for
  2428 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2429 hnorm.  Other constants have been entirely removed in favor of the
  2430 polymorphic versions (INCOMPATIBILITY):
  2431 
  2432   approx        <-- capprox
  2433   HFinite       <-- CFinite
  2434   HInfinite     <-- CInfinite
  2435   Infinitesimal <-- CInfinitesimal
  2436   monad         <-- cmonad
  2437   galaxy        <-- cgalaxy
  2438   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2439   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2440   (ns)deriv     <-- (ns)cderiv
  2441 
  2442 
  2443 *** HOL-Algebra ***
  2444 
  2445 * Formalisation of ideals and the quotient construction over rings.
  2446 
  2447 * Order and lattice theory no longer based on records.
  2448 INCOMPATIBILITY.
  2449 
  2450 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2451 greatest_closed.  INCOMPATIBILITY.
  2452 
  2453 * Method algebra is now set up via an attribute.  For examples see
  2454 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2455 of algebraic structures.
  2456 
  2457 * Renamed theory CRing to Ring.
  2458 
  2459 
  2460 *** HOL-Nominal ***
  2461 
  2462 * Substantial, yet incomplete support for nominal datatypes (binding
  2463 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2464 src/HOL/Nominal/Examples.  Prospective users should consult
  2465 http://isabelle.in.tum.de/nominal/
  2466 
  2467 
  2468 *** ML ***
  2469 
  2470 * ML basics: just one true type int, which coincides with IntInf.int
  2471 (even on SML/NJ).
  2472 
  2473 * ML within Isar: antiquotations allow to embed statically-checked
  2474 formal entities in the source, referring to the context available at
  2475 compile-time.  For example:
  2476 
  2477 ML {* @{sort "{zero,one}"} *}
  2478 ML {* @{typ "'a => 'b"} *}
  2479 ML {* @{term "%x. x"} *}
  2480 ML {* @{prop "x == y"} *}
  2481 ML {* @{ctyp "'a => 'b"} *}
  2482 ML {* @{cterm "%x. x"} *}
  2483 ML {* @{cprop "x == y"} *}
  2484 ML {* @{thm asm_rl} *}
  2485 ML {* @{thms asm_rl} *}
  2486 ML {* @{type_name c} *}
  2487 ML {* @{type_syntax c} *}
  2488 ML {* @{const_name c} *}
  2489 ML {* @{const_syntax c} *}
  2490 ML {* @{context} *}
  2491 ML {* @{theory} *}
  2492 ML {* @{theory Pure} *}
  2493 ML {* @{theory_ref} *}
  2494 ML {* @{theory_ref Pure} *}
  2495 ML {* @{simpset} *}
  2496 ML {* @{claset} *}
  2497 ML {* @{clasimpset} *}
  2498 
  2499 The same works for sources being ``used'' within an Isar context.
  2500 
  2501 * ML in Isar: improved error reporting; extra verbosity with
  2502 ML_Context.trace enabled.
  2503 
  2504 * Pure/General/table.ML: the join operations now works via exceptions
  2505 DUP/SAME instead of type option. This is simpler in simple cases, and
  2506 admits slightly more efficient complex applications.
  2507 
  2508 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2509 use Context.generic instead of just theory.
  2510 
  2511 * Pure: datatype Context.generic joins theory/Proof.context and
  2512 provides some facilities for code that works in either kind of
  2513 context, notably GenericDataFun for uniform theory and proof data.
  2514 
  2515 * Pure: simplified internal attribute type, which is now always
  2516 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2517 local (Proof.context) attributes have been discontinued, while
  2518 minimizing code duplication. Thm.rule_attribute and
  2519 Thm.declaration_attribute build canonical attributes; see also structure
  2520 Context for further operations on Context.generic, notably
  2521 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2522 declarations and definitions.
  2523 
  2524 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2525 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2526 init only required for impure data. INCOMPATIBILITY: empty really need
  2527 to be empty (no dependencies on theory content!)
  2528 
  2529 * Pure/kernel: consts certification ignores sort constraints given in
  2530 signature declarations. (This information is not relevant to the
  2531 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2532 potential INCOMPATIBILITY.
  2533 
  2534 * Pure: axiomatic type classes are now purely definitional, with
  2535 explicit proofs of class axioms and super class relations performed
  2536 internally. See Pure/axclass.ML for the main internal interfaces --
  2537 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2538 AxClass.axiomatize_class/classrel/arity supersede
  2539 Sign.add_classes/classrel/arities.
  2540 
  2541 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2542 global/local versions on theory vs. Proof.context have been
  2543 discontinued; Attrib.syntax and Method.syntax have been adapted
  2544 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2545 attributes, methods, etc.
  2546 
  2547 * Pure: several functions of signature "... -> theory -> theory * ..."
  2548 have been reoriented to "... -> theory -> ... * theory" in order to
  2549 allow natural usage in combination with the ||>, ||>>, |-> and
  2550 fold_map combinators.
  2551 
  2552 * Pure: official theorem names (closed derivations) and additional
  2553 comments (tags) are now strictly separate.  Name hints -- which are
  2554 maintained as tags -- may be attached any time without affecting the
  2555 derivation.
  2556 
  2557 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2558 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2559 achieve the old behaviour.
  2560 
  2561 * Pure: the "Goal" constant is now called "prop", supporting a
  2562 slightly more general idea of ``protecting'' meta-level rule
  2563 statements.
  2564 
  2565 * Pure: Logic.(un)varify only works in a global context, which is now
  2566 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2567 Logic.legacy_(un)varify as temporary workaround.
  2568 
  2569 * Pure: structure Name provides scalable operations for generating
  2570 internal variable names, notably Name.variants etc.  This replaces
  2571 some popular functions from term.ML:
  2572 
  2573   Term.variant		->  Name.variant
  2574   Term.variantlist	->  Name.variant_list
  2575   Term.invent_names	->  Name.invent_list
  2576 
  2577 Note that low-level renaming rarely occurs in new code -- operations
  2578 from structure Variable are used instead (see below).
  2579 
  2580 * Pure: structure Variable provides fundamental operations for proper
  2581 treatment of fixed/schematic variables in a context.  For example,
  2582 Variable.import introduces fixes for schematics of given facts and
  2583 Variable.export reverses the effect (up to renaming) -- this replaces
  2584 various freeze_thaw operations.
  2585 
  2586 * Pure: structure Goal provides simple interfaces for
  2587 init/conclude/finish and tactical prove operations (replacing former
  2588 Tactic.prove).  Goal.prove is the canonical way to prove results
  2589 within a given context; Goal.prove_global is a degraded version for
  2590 theory level goals, including a global Drule.standard.  Note that
  2591 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2592 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2593 in a locale context).
  2594 
  2595 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2596 and type checking (Syntax.check_term etc.), with common combinations
  2597 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2598 which are considered legacy and await removal.
  2599 
  2600 * Pure/Syntax: generic interfaces for type unchecking
  2601 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2602 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2603 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2604 available for convenience, but refer to the very same operations using
  2605 a mere theory instead of a full context.
  2606 
  2607 * Isar: simplified treatment of user-level errors, using exception
  2608 ERROR of string uniformly.  Function error now merely raises ERROR,
  2609 without any side effect on output channels.  The Isar toplevel takes
  2610 care of proper display of ERROR exceptions.  ML code may use plain
  2611 handle/can/try; cat_error may be used to concatenate errors like this:
  2612 
  2613   ... handle ERROR msg => cat_error msg "..."
  2614 
  2615 Toplevel ML code (run directly or through the Isar toplevel) may be
  2616 embedded into the Isar toplevel with exception display/debug like
  2617 this:
  2618 
  2619   Isar.toplevel (fn () => ...)
  2620 
  2621 INCOMPATIBILITY, removed special transform_error facilities, removed
  2622 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2623 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2624 -- use plain ERROR instead.
  2625 
  2626 * Isar: theory setup now has type (theory -> theory), instead of a
  2627 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2628 
  2629 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2630 ProofContext.debug/verbose flags.
  2631 
  2632 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2633 theory before entering a proof state.  Transactions now always see a
  2634 quasi-functional intermediate checkpoint, both in interactive and
  2635 batch mode.
  2636 
  2637 * Isar: simplified interfaces for outer syntax.  Renamed
  2638 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2639 OuterSyntax.add_parsers -- this functionality is now included in
  2640 OuterSyntax.command etc.  INCOMPATIBILITY.
  2641 
  2642 * Simplifier: the simpset of a running simplification process now
  2643 contains a proof context (cf. Simplifier.the_context), which is the
  2644 very context that the initial simpset has been retrieved from (by
  2645 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2646 (solver, looper etc.) may depend on arbitrary proof data.
  2647 
  2648 * Simplifier.inherit_context inherits the proof context (plus the
  2649 local bounds) of the current simplification process; any simproc
  2650 etc. that calls the Simplifier recursively should do this!  Removed
  2651 former Simplifier.inherit_bounds, which is already included here --
  2652 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2653 specify an explicit context using Simplifier.context/theory_context.
  2654 
  2655 * Simplifier/Classical Reasoner: more abstract interfaces
  2656 change_simpset/claset for modifying the simpset/claset reference of a
  2657 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2658 INCOMPATIBILITY.
  2659 
  2660 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2661 "Trueprop" etc.
  2662 
  2663 
  2664 *** System ***
  2665 
  2666 * settings: the default heap location within ISABELLE_HOME_USER now
  2667 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2668 Isabelle installations.
  2669 
  2670 * isabelle-process: option -S (secure mode) disables some critical
  2671 operations, notably runtime compilation and evaluation of ML source
  2672 code.
  2673 
  2674 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2675 
  2676 * Support for parallel execution, using native multicore support of
  2677 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2678 independent theories, according to the given theory header
  2679 specifications. The maximum number of worker threads is specified via
  2680 usedir option -M or the "max-threads" setting in Proof General. A
  2681 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2682 to 6 on a 8-core machine.  User-code needs to observe certain
  2683 guidelines for thread-safe programming, see appendix A in the Isar
  2684 Implementation manual.
  2685 
  2686 
  2687 
  2688 New in Isabelle2005 (October 2005)
  2689 ----------------------------------
  2690 
  2691 *** General ***
  2692 
  2693 * Theory headers: the new header syntax for Isar theories is
  2694 
  2695   theory <name>
  2696   imports <theory1> ... <theoryN>
  2697   uses <file1> ... <fileM>
  2698   begin
  2699 
  2700 where the 'uses' part is optional.  The previous syntax
  2701 
  2702   theory <name> = <theory1> + ... + <theoryN>:
  2703 
  2704 will disappear in the next release.  Use isatool fixheaders to convert
  2705 existing theory files.  Note that there is no change in ancient
  2706 non-Isar theories now, but these will disappear soon.
  2707 
  2708 * Theory loader: parent theories can now also be referred to via
  2709 relative and absolute paths.
  2710 
  2711 * Command 'find_theorems' searches for a list of criteria instead of a
  2712 list of constants. Known criteria are: intro, elim, dest, name:string,
  2713 simp:term, and any term. Criteria can be preceded by '-' to select
  2714 theorems that do not match. Intro, elim, dest select theorems that
  2715 match the current goal, name:s selects theorems whose fully qualified
  2716 name contain s, and simp:term selects all simplification rules whose
  2717 lhs match term.  Any other term is interpreted as pattern and selects
  2718 all theorems matching the pattern. Available in ProofGeneral under
  2719 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2720 
  2721   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2722 
  2723 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2724 matching the current goal as introduction rule and not having "HOL."
  2725 in their name (i.e. not being defined in theory HOL).
  2726 
  2727 * Command 'thms_containing' has been discontinued in favour of
  2728 'find_theorems'; INCOMPATIBILITY.
  2729 
  2730 * Communication with Proof General is now 8bit clean, which means that
  2731 Unicode text in UTF-8 encoding may be used within theory texts (both
  2732 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2733 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2734 
  2735   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2736   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2737 
  2738 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2739 Classical Reasoner.  Typical big applications run around 2 times
  2740 faster.
  2741 
  2742 
  2743 *** Document preparation ***
  2744 
  2745 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2746 of raw sources.  Only those symbols that do not require additional
  2747 LaTeX packages (depending on comments in isabellesym.sty) are
  2748 displayed properly, everything else is left verbatim.  isatool display
  2749 and isatool print are used as front ends (these are subject to the
  2750 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2751 
  2752 * Command tags control specific markup of certain regions of text,
  2753 notably folding and hiding.  Predefined tags include "theory" (for
  2754 theory begin and end), "proof" for proof commands, and "ML" for
  2755 commands involving ML code; the additional tags "visible" and
  2756 "invisible" are unused by default.  Users may give explicit tag
  2757 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2758 interpretation of tags is determined by the LaTeX job during document
  2759 preparation: see option -V of isatool usedir, or options -n and -t of
  2760 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2761 \isadroptag.
  2762 
  2763 Several document versions may be produced at the same time via isatool
  2764 usedir (the generated index.html will link all of them).  Typical
  2765 specifications include ''-V document=theory,proof,ML'' to present
  2766 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2767 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2768 these parts without any formal replacement text.  The Isabelle site
  2769 default settings produce ''document'' and ''outline'' versions as
  2770 specified above.
  2771 
  2772 * Several new antiquotations:
  2773 
  2774   @{term_type term} prints a term with its type annotated;
  2775 
  2776   @{typeof term} prints the type of a term;
  2777 
  2778   @{const const} is the same as @{term const}, but checks that the
  2779   argument is a known logical constant;
  2780 
  2781   @{term_style style term} and @{thm_style style thm} print a term or
  2782   theorem applying a "style" to it
  2783 
  2784   @{ML text}
  2785 
  2786 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2787 definitions, equations, inequations etc., 'concl' printing only the
  2788 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2789 to print the specified premise.  TermStyle.add_style provides an ML
  2790 interface for introducing further styles.  See also the "LaTeX Sugar"
  2791 document practical applications.  The ML antiquotation prints
  2792 type-checked ML expressions verbatim.
  2793 
  2794 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2795 and 'text' support optional locale specification '(in loc)', which
  2796 specifies the default context for interpreting antiquotations.  For
  2797 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2798 
  2799 * Option 'locale=NAME' of antiquotations specifies an alternative
  2800 context interpreting the subsequent argument.  For example: @{thm
  2801 [locale=lattice] inf_assoc}.
  2802 
  2803 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2804 a proof context.
  2805 
  2806 * Proper output of antiquotations for theory commands involving a
  2807 proof context (such as 'locale' or 'theorem (in loc) ...').
  2808 
  2809 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2810 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2811 
  2812 * isatool usedir: new option -C (default true) controls whether option
  2813 -D should include a copy of the original document directory; -C false
  2814 prevents unwanted effects such as copying of administrative CVS data.
  2815 
  2816 
  2817 *** Pure ***
  2818 
  2819 * Considerably improved version of 'constdefs' command.  Now performs
  2820 automatic type-inference of declared constants; additional support for
  2821 local structure declarations (cf. locales and HOL records), see also
  2822 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2823 sequential dependencies of definitions within a single 'constdefs'
  2824 section; moreover, the declared name needs to be an identifier.  If
  2825 all fails, consider to fall back on 'consts' and 'defs' separately.
  2826 
  2827 * Improved indexed syntax and implicit structures.  First of all,
  2828 indexed syntax provides a notational device for subscripted
  2829 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2830 expressions.  Secondly, in a local context with structure
  2831 declarations, number indexes \<^sub>n or the empty index (default
  2832 number 1) refer to a certain fixed variable implicitly; option
  2833 show_structs controls printing of implicit structures.  Typical
  2834 applications of these concepts involve record types and locales.
  2835 
  2836 * New command 'no_syntax' removes grammar declarations (and
  2837 translations) resulting from the given syntax specification, which is
  2838 interpreted in the same manner as for the 'syntax' command.
  2839 
  2840 * 'Advanced' translation functions (parse_translation etc.) may depend
  2841 on the signature of the theory context being presently used for
  2842 parsing/printing, see also isar-ref manual.
  2843 
  2844 * Improved 'oracle' command provides a type-safe interface to turn an
  2845 ML expression of type theory -> T -> term into a primitive rule of
  2846 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2847 is already included here); see also FOL/ex/IffExample.thy;
  2848 INCOMPATIBILITY.
  2849 
  2850 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2851 before); "cI" is no longer bound, use "c.intro" instead.
  2852 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2853 axclasses vs. locales.
  2854 
  2855 * Improved internal renaming of symbolic identifiers -- attach primes
  2856 instead of base 26 numbers.
  2857 
  2858 * New flag show_question_marks controls printing of leading question
  2859 marks in schematic variable names.
  2860 
  2861 * In schematic variable names, *any* symbol following \<^isub> or
  2862 \<^isup> is now treated as part of the base name.  For example, the
  2863 following works without printing of awkward ".0" indexes:
  2864 
  2865   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2866     by simp
  2867 
  2868 * Inner syntax includes (*(*nested*) comments*).
  2869 
  2870 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2871 annotations as "(00...)".
  2872 
  2873 * Clear separation of logical types and nonterminals, where the latter
  2874 may only occur in 'syntax' specifications or type abbreviations.
  2875 Before that distinction was only partially implemented via type class
  2876 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2877 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2878 exotic syntax specifications may require further adaption
  2879 (e.g. Cube/Cube.thy).
  2880 
  2881 * Removed obsolete type class "logic", use the top sort {} instead.
  2882 Note that non-logical types should be declared as 'nonterminals'
  2883 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2884 specifications.
  2885 
  2886 * Attributes 'induct' and 'cases': type or set names may now be
  2887 locally fixed variables as well.
  2888 
  2889 * Simplifier: can now control the depth to which conditional rewriting
  2890 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2891 Limit.
  2892 
  2893 * Simplifier: simplification procedures may now take the current
  2894 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2895 interface), which is very useful for calling the Simplifier
  2896 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2897 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2898 low-level mk_simproc no longer applies Logic.varify internally, to
  2899 allow for use in a context of fixed variables.
  2900 
  2901 * thin_tac now works even if the assumption being deleted contains !!
  2902 or ==>.  More generally, erule now works even if the major premise of
  2903 the elimination rule contains !! or ==>.
  2904 
  2905 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2906 
  2907 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2908 from Pure, which contains all common declarations already.  Both
  2909 theories are defined via plain Isabelle/Isar .thy files.
  2910 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2911 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2912 use isatool fixcpure to adapt your theory and ML sources.
  2913 
  2914 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2915 selections of theorems in named facts via index ranges.
  2916 
  2917 * 'print_theorems': in theory mode, really print the difference
  2918 wrt. the last state (works for interactive theory development only),
  2919 in proof mode print all local facts (cf. 'print_facts');
  2920 
  2921 * 'hide': option '(open)' hides only base names.
  2922 
  2923 * More efficient treatment of intermediate checkpoints in interactive
  2924 theory development.
  2925 
  2926 * Code generator is now invoked via code_module (incremental code
  2927 generation) and code_library (modular code generation, ML structures
  2928 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2929 must be quoted when used as identifiers.
  2930 
  2931 * New 'value' command for reading, evaluating and printing terms using
  2932 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2933 quoted when used as identifier.
  2934 
  2935 
  2936 *** Locales ***
  2937 
  2938 * New commands for the interpretation of locale expressions in
  2939 theories (1), locales (2) and proof contexts (3).  These generate
  2940 proof obligations from the expression specification.  After the
  2941 obligations have been discharged, theorems of the expression are added
  2942 to the theory, target locale or proof context.  The synopsis of the
  2943 commands is a follows:
  2944 
  2945   (1) interpretation expr inst
  2946   (2) interpretation target < expr
  2947   (3) interpret expr inst
  2948 
  2949 Interpretation in theories and proof contexts require a parameter
  2950 instantiation of terms from the current context.  This is applied to
  2951 specifications and theorems of the interpreted expression.
  2952 Interpretation in locales only permits parameter renaming through the
  2953 locale expression.  Interpretation is smart in that interpretations
  2954 that are active already do not occur in proof obligations, neither are
  2955 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2956 inspect active interpretations of a particular locale.  For details,
  2957 see the Isar Reference manual.  Examples can be found in
  2958 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2959 
  2960 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2961 'interpret' instead.
  2962 
  2963 * New context element 'constrains' for adding type constraints to
  2964 parameters.
  2965 
  2966 * Context expressions: renaming of parameters with syntax
  2967 redeclaration.
  2968 
  2969 * Locale declaration: 'includes' disallowed.
  2970 
  2971 * Proper static binding of attribute syntax -- i.e. types / terms /
  2972 facts mentioned as arguments are always those of the locale definition
  2973 context, independently of the context of later invocations.  Moreover,
  2974 locale operations (renaming and type / term instantiation) are applied
  2975 to attribute arguments as expected.
  2976 
  2977 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2978 actual attributes; rare situations may require Attrib.attribute to
  2979 embed those attributes into Attrib.src that lack concrete syntax.
  2980 Attribute implementations need to cooperate properly with the static
  2981 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2982 Attrib.XXX_thm etc. already do the right thing without further
  2983 intervention.  Only unusual applications -- such as "where" or "of"
  2984 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2985 on the context and the facts involved -- may have to assign parsed
  2986 values to argument tokens explicitly.
  2987 
  2988 * Changed parameter management in theorem generation for long goal
  2989 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2990 theorem statement in rare situations.
  2991 
  2992 * Locale inspection command 'print_locale' omits notes elements.  Use
  2993 'print_locale!' to have them included in the output.
  2994 
  2995 
  2996 *** Provers ***
  2997 
  2998 * Provers/hypsubst.ML: improved version of the subst method, for
  2999 single-step rewriting: it now works in bound variable contexts. New is
  3000 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  3001 rewrite a different subterm than the original subst method, which is
  3002 still available as 'simplesubst'.
  3003 
  3004 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  3005 and quasi orders.
  3006 
  3007 * Provers/trancl.ML: new transitivity reasoner for transitive and
  3008 reflexive-transitive closure of relations.
  3009 
  3010 * Provers/blast.ML: new reference depth_limit to make blast's depth
  3011 limit (previously hard-coded with a value of 20) user-definable.
  3012 
  3013 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  3014 is peformed already.  Object-logics merely need to finish their
  3015 initial simpset configuration as before.  INCOMPATIBILITY.
  3016 
  3017 
  3018 *** HOL ***
  3019 
  3020 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3021 
  3022   syntax (epsilon)
  3023     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3024 
  3025 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3026 and x-symbol; use option '-m epsilon' to get it actually printed.
  3027 Moreover, the mathematically important symbolic identifier \<epsilon>
  3028 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3029 
  3030 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3031 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3032 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3033 support corresponding Isar calculations.
  3034 
  3035 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3036 instead of ":".
  3037 
  3038 * theory SetInterval: changed the syntax for open intervals:
  3039 
  3040   Old       New
  3041   {..n(}    {..<n}
  3042   {)n..}    {n<..}
  3043   {m..n(}   {m..<n}
  3044   {)m..n}   {m<..n}
  3045   {)m..n(}  {m<..<n}
  3046 
  3047 The old syntax is still supported but will disappear in the next
  3048 release.  For conversion use the following Emacs search and replace
  3049 patterns (these are not perfect but work quite well):
  3050 
  3051   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3052   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3053 
  3054 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3055 equalities in commutative rings; method 'algebra' provides a generic
  3056 interface.
  3057 
  3058 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3059 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3060 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3061 be a tuple pattern.
  3062 
  3063 Some new syntax forms are available:
  3064 
  3065   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3066   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3067   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3068   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3069 
  3070 The latter form "\<Sum>x < k. e" used to be based on a separate
  3071 function "Summation", which has been discontinued.
  3072 
  3073 * theory Finite_Set: in structured induction proofs, the insert case
  3074 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3075 (insert F x)'.
  3076 
  3077 * The 'refute' command has been extended to support a much larger
  3078 fragment of HOL, including axiomatic type classes, constdefs and
  3079 typedefs, inductive datatypes and recursion.
  3080 
  3081 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3082 Requires zChaff with proof generation to be installed.  See
  3083 HOL/ex/SAT_Examples.thy for examples.
  3084 
  3085 * Datatype induction via method 'induct' now preserves the name of the
  3086 induction variable. For example, when proving P(xs::'a list) by
  3087 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3088 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3089 in unstructured proof scripts.
  3090 
  3091 * Reworked implementation of records.  Improved scalability for
  3092 records with many fields, avoiding performance problems for type
  3093 inference. Records are no longer composed of nested field types, but
  3094 of nested extension types. Therefore the record type only grows linear
  3095 in the number of extensions and not in the number of fields.  The
  3096 top-level (users) view on records is preserved.  Potential
  3097 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3098 old record representation. The type generated for a record is called
  3099 <record_name>_ext_type.
  3100 
  3101 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3102 proofs triggered by a record definition or a simproc (if
  3103 quick_and_dirty is enabled).  Definitions of large records can take
  3104 quite long.
  3105 
  3106 New simproc record_upd_simproc for simplification of multiple record
  3107 updates enabled by default.  Moreover, trivial updates are also
  3108 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3109 occasionally, since simplification is more powerful by default.
  3110 
  3111 * typedef: proper support for polymorphic sets, which contain extra
  3112 type-variables in the term.
  3113 
  3114 * Simplifier: automatically reasons about transitivity chains
  3115 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3116 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3117 old proofs break occasionally as simplification may now solve more
  3118 goals than previously.
  3119 
  3120 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3121 present.  Works for all partial orders (class "order"), in particular
  3122 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3123 just like y <= x.
  3124 
  3125 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3126 bound variable or a constant then the let is unfolded.  Otherwise
  3127 first a is simplified to b, and then f b is simplified to g. If
  3128 possible we abstract b from g arriving at "let x = b in h x",
  3129 otherwise we unfold the let and arrive at g.  The simproc can be
  3130 enabled/disabled by the reference use_let_simproc.  Potential
  3131 INCOMPATIBILITY since simplification is more powerful by default.
  3132 
  3133 * Classical reasoning: the meson method now accepts theorems as arguments.
  3134 
  3135 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3136 jobs to provide advice on the provability of subgoals.
  3137 
  3138 * Theory OrderedGroup and Ring_and_Field: various additions and
  3139 improvements to faciliate calculations involving equalities and
  3140 inequalities.
  3141 
  3142 The following theorems have been eliminated or modified
  3143 (INCOMPATIBILITY):
  3144 
  3145   abs_eq             now named abs_of_nonneg
  3146   abs_of_ge_0        now named abs_of_nonneg
  3147   abs_minus_eq       now named abs_of_nonpos
  3148   imp_abs_id         now named abs_of_nonneg
  3149   imp_abs_neg_id     now named abs_of_nonpos
  3150   mult_pos           now named mult_pos_pos
  3151   mult_pos_le        now named mult_nonneg_nonneg
  3152   mult_pos_neg_le    now named mult_nonneg_nonpos
  3153   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3154   mult_neg           now named mult_neg_neg
  3155   mult_neg_le        now named mult_nonpos_nonpos
  3156 
  3157 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3158      
  3159      zero_le_square
  3160      not_square_less_zero 
  3161 
  3162   The following lemmas have been deleted from Real/RealPow:
  3163   
  3164      realpow_zero_zero
  3165      realpow_two
  3166      realpow_less
  3167      zero_le_power
  3168      realpow_two_le
  3169      abs_realpow_two
  3170      realpow_two_abs     
  3171 
  3172 * Theory Parity: added rules for simplifying exponents.
  3173 
  3174 * Theory List:
  3175 
  3176 The following theorems have been eliminated or modified
  3177 (INCOMPATIBILITY):
  3178 
  3179   list_all_Nil       now named list_all.simps(1)
  3180   list_all_Cons      now named list_all.simps(2)
  3181   list_all_conv      now named list_all_iff
  3182   set_mem_eq         now named mem_iff
  3183 
  3184 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3185 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3186 
  3187 
  3188 *** HOL-Complex ***
  3189 
  3190 * Theory RealDef: better support for embedding natural numbers and
  3191 integers in the reals.
  3192 
  3193 The following theorems have been eliminated or modified
  3194 (INCOMPATIBILITY):
  3195 
  3196   exp_ge_add_one_self  now requires no hypotheses
  3197   real_of_int_add      reversed direction of equality (use [symmetric])
  3198   real_of_int_minus    reversed direction of equality (use [symmetric])
  3199   real_of_int_diff     reversed direction of equality (use [symmetric])
  3200   real_of_int_mult     reversed direction of equality (use [symmetric])
  3201 
  3202 * Theory RComplete: expanded support for floor and ceiling functions.
  3203 
  3204 * Theory Ln is new, with properties of the natural logarithm
  3205 
  3206 * Hyperreal: There is a new type constructor "star" for making
  3207 nonstandard types.  The old type names are now type synonyms:
  3208 
  3209   hypreal = real star
  3210   hypnat = nat star
  3211   hcomplex = complex star
  3212 
  3213 * Hyperreal: Many groups of similarly-defined constants have been
  3214 replaced by polymorphic versions (INCOMPATIBILITY):
  3215 
  3216   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3217 
  3218   starset      <-- starsetNat, starsetC
  3219   *s*          <-- *sNat*, *sc*
  3220   starset_n    <-- starsetNat_n, starsetC_n
  3221   *sn*         <-- *sNatn*, *scn*
  3222   InternalSets <-- InternalNatSets, InternalCSets
  3223 
  3224   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3225   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3226   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3227   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3228   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3229 
  3230 * Hyperreal: Many type-specific theorems have been removed in favor of
  3231 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3232 
  3233   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3234   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3235   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3236   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3237   right_minus <-- hypreal_add_minus
  3238   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3239   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3240   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3241   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3242   mult_1_right <-- hcomplex_mult_one_right
  3243   mult_zero_left <-- hcomplex_mult_zero_left
  3244   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3245   right_distrib <-- hypnat_add_mult_distrib2
  3246   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3247   right_inverse <-- hypreal_mult_inverse
  3248   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3249   order_refl <-- {hypreal,hypnat}_le_refl
  3250   order_trans <-- {hypreal,hypnat}_le_trans
  3251   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3252   order_less_le <-- {hypreal,hypnat}_less_le
  3253   linorder_linear <-- {hypreal,hypnat}_le_linear
  3254   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3255   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3256   add_nonneg_nonneg <-- hypreal_le_add_order
  3257 
  3258 * Hyperreal: Separate theorems having to do with type-specific
  3259 versions of constants have been merged into theorems that apply to the
  3260 new polymorphic constants (INCOMPATIBILITY):
  3261 
  3262   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3263   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3264   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3265   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3266   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3267   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3268   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3269   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3270   STAR_diff <-- {STAR,STARC}_diff
  3271   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3272     STARC_hcomplex_of_complex}_image_subset
  3273   starset_n_Un <-- starset{Nat,C}_n_Un
  3274   starset_n_Int <-- starset{Nat,C}_n_Int
  3275   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3276   starset_n_diff <-- starset{Nat,C}_n_diff
  3277   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3278   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3279   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3280   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3281   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3282   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3283   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3284   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3285   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3286   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3287   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3288   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3289   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3290   starfun_diff <-- starfun{C,RC,CR}_diff
  3291   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3292   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3293   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3294   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3295   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3296   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3297   starfun_Id <-- starfunC_Id
  3298   starfun_approx <-- starfun{Nat,CR}_approx
  3299   starfun_capprox <-- starfun{C,RC}_capprox
  3300   starfun_abs <-- starfunNat_rabs
  3301   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3302   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3303   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3304   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3305   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3306   starfun_add_approx <-- starfunCR_add_approx
  3307   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3308   starfun_divide <-- starfun{C,CR,RC}_divide
  3309   starfun_n <-- starfun{Nat,C}_n
  3310   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3311   starfun_n_add <-- starfun{Nat,C}_n_add
  3312   starfun_n_add_minus <-- starfunNat_n_add_minus
  3313   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3314   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3315   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3316 
  3317   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3318   star_n_minus <-- {hypreal,hcomplex}_minus
  3319   star_n_diff <-- {hypreal,hcomplex}_diff
  3320   star_n_mult <-- {hypreal,hcomplex}_mult
  3321   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3322   star_n_le <-- {hypreal,hypnat}_le
  3323   star_n_less <-- {hypreal,hypnat}_less
  3324   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3325   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3326   star_n_abs <-- hypreal_hrabs
  3327   star_n_divide <-- hcomplex_divide
  3328 
  3329   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3330   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3331   star_of_diff <-- hypreal_of_real_diff
  3332   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3333   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3334   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3335   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3336   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3337   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3338   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3339   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3340   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3341   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3342   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3343   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3344   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3345   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3346   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3347   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3348   star_of_power <-- hypreal_of_real_power
  3349   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3350 
  3351 * Hyperreal: new method "transfer" that implements the transfer
  3352 principle of nonstandard analysis. With a subgoal that mentions
  3353 nonstandard types like "'a star", the command "apply transfer"
  3354 replaces it with an equivalent one that mentions only standard types.
  3355 To be successful, all free variables must have standard types; non-
  3356 standard variables must have explicit universal quantifiers.
  3357 
  3358 * Hyperreal: A theory of Taylor series.
  3359 
  3360 
  3361 *** HOLCF ***
  3362 
  3363 * Discontinued special version of 'constdefs' (which used to support
  3364 continuous functions) in favor of the general Pure one with full
  3365 type-inference.
  3366 
  3367 * New simplification procedure for solving continuity conditions; it
  3368 is much faster on terms with many nested lambda abstractions (cubic
  3369 instead of exponential time).
  3370 
  3371 * New syntax for domain package: selector names are now optional.
  3372 Parentheses should be omitted unless argument is lazy, for example:
  3373 
  3374   domain 'a stream = cons "'a" (lazy "'a stream")
  3375 
  3376 * New command 'fixrec' for defining recursive functions with pattern
  3377 matching; defining multiple functions with mutual recursion is also
  3378 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3379 sinr, or any data constructor defined by the domain package. The given
  3380 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3381 syntax and examples.
  3382 
  3383 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3384 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3385 but the proof obligation additionally includes an admissibility
  3386 requirement. The packages generate instances of class cpo or pcpo,
  3387 with continuity and strictness theorems for Rep and Abs.
  3388 
  3389 * HOLCF: Many theorems have been renamed according to a more standard naming
  3390 scheme (INCOMPATIBILITY):
  3391 
  3392   foo_inject:  "foo$x = foo$y ==> x = y"
  3393   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3394   foo_less:    "(foo$x << foo$y) = (x << y)"
  3395   foo_strict:  "foo$UU = UU"
  3396   foo_defined: "... ==> foo$x ~= UU"
  3397   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3398 
  3399 
  3400 *** ZF ***
  3401 
  3402 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3403 including the First Isomorphism Theorem (on quotienting by the kernel
  3404 of a homomorphism).
  3405 
  3406 * ZF/Simplifier: install second copy of type solver that actually
  3407 makes use of TC rules declared to Isar proof contexts (or locales);
  3408 the old version is still required for ML proof scripts.
  3409 
  3410 
  3411 *** Cube ***
  3412 
  3413 * Converted to Isar theory format; use locales instead of axiomatic
  3414 theories.
  3415 
  3416 
  3417 *** ML ***
  3418 
  3419 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3420 for ||>, ||>>, |>>,
  3421 
  3422 * Pure/library.ML no longer defines its own option datatype, but uses
  3423 that of the SML basis, which has constructors NONE and SOME instead of
  3424 None and Some, as well as exception Option.Option instead of OPTION.
  3425 The functions the, if_none, is_some, is_none have been adapted
  3426 accordingly, while Option.map replaces apsome.
  3427 
  3428 * Pure/library.ML: the exception LIST has been given up in favour of
  3429 the standard exceptions Empty and Subscript, as well as
  3430 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3431 superceded by the standard hd and tl functions etc.
  3432 
  3433 A number of basic list functions are no longer exported to the ML
  3434 toplevel, as they are variants of predefined functions.  The following
  3435 suggests how one can translate existing code:
  3436 
  3437     rev_append xs ys = List.revAppend (xs, ys)
  3438     nth_elem (i, xs) = List.nth (xs, i)
  3439     last_elem xs = List.last xs
  3440     flat xss = List.concat xss
  3441     seq fs = List.app fs
  3442     partition P xs = List.partition P xs
  3443     mapfilter f xs = List.mapPartial f xs
  3444 
  3445 * Pure/library.ML: several combinators for linear functional
  3446 transformations, notably reverse application and composition:
  3447 
  3448   x |> f                f #> g
  3449   (x, y) |-> f          f #-> g
  3450 
  3451 * Pure/library.ML: introduced/changed precedence of infix operators:
  3452 
  3453   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3454   infix 2 ?;
  3455   infix 3 o oo ooo oooo;
  3456   infix 4 ~~ upto downto;
  3457 
  3458 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3459 infix operators.
  3460 
  3461 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3462 fold_map support linear functional transformations and nesting.  For
  3463 example:
  3464 
  3465   fold f [x1, ..., xN] y =
  3466     y |> f x1 |> ... |> f xN
  3467 
  3468   (fold o fold) f [xs1, ..., xsN] y =
  3469     y |> fold f xs1 |> ... |> fold f xsN
  3470 
  3471   fold f [x1, ..., xN] =
  3472     f x1 #> ... #> f xN
  3473 
  3474   (fold o fold) f [xs1, ..., xsN] =
  3475     fold f xs1 #> ... #> fold f xsN
  3476 
  3477 * Pure/library.ML: the following selectors on type 'a option are
  3478 available:
  3479 
  3480   the:               'a option -> 'a  (*partial*)
  3481   these:             'a option -> 'a  where 'a = 'b list
  3482   the_default: 'a -> 'a option -> 'a
  3483   the_list:          'a option -> 'a list
  3484 
  3485 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3486 basic operations for association lists, following natural argument
  3487 order; moreover the explicit equality predicate passed here avoids
  3488 potentially expensive polymorphic runtime equality checks.
  3489 The old functions may be expressed as follows:
  3490 
  3491   assoc = uncurry (AList.lookup (op =))
  3492   assocs = these oo AList.lookup (op =)
  3493   overwrite = uncurry (AList.update (op =)) o swap
  3494 
  3495 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3496 
  3497   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3498   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3499 
  3500 replacing make_keylist and keyfilter (occassionally used)
  3501 Naive rewrites:
  3502 
  3503   make_keylist = AList.make
  3504   keyfilter = AList.find (op =)
  3505 
  3506 * eq_fst and eq_snd now take explicit equality parameter, thus
  3507   avoiding eqtypes. Naive rewrites:
  3508 
  3509     eq_fst = eq_fst (op =)
  3510     eq_snd = eq_snd (op =)
  3511 
  3512 * Removed deprecated apl and apr (rarely used).
  3513   Naive rewrites:
  3514 
  3515     apl (n, op) =>>= curry op n
  3516     apr (op, m) =>>= fn n => op (n, m)
  3517 
  3518 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3519 provides a reasonably efficient light-weight implementation of sets as
  3520 lists.
  3521 
  3522 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3523 few new operations; existing lookup and update are now curried to
  3524 follow natural argument order (for use with fold etc.);
  3525 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3526 
  3527 * Pure/General: output via the Isabelle channels of
  3528 writeln/warning/error etc. is now passed through Output.output, with a
  3529 hook for arbitrary transformations depending on the print_mode
  3530 (cf. Output.add_mode -- the first active mode that provides a output
  3531 function wins).  Already formatted output may be embedded into further
  3532 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3533 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3534 accommodate easy composition of diagnostic messages etc.  Programmers
  3535 rarely need to care about Output.output or Output.raw at all, with
  3536 some notable exceptions: Output.output is required when bypassing the
  3537 standard channels (writeln etc.), or in token translations to produce
  3538 properly formatted results; Output.raw is required when capturing
  3539 already output material that will eventually be presented to the user
  3540 a second time.  For the default print mode, both Output.output and
  3541 Output.raw have no effect.
  3542 
  3543 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3544 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3545 cumulative results are displayed at the end of a batch session.
  3546 
  3547 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3548 replaced by File.platform_path and File.shell_path (with appropriate
  3549 hooks).  This provides a clean interface for unusual systems where the
  3550 internal and external process view of file names are different.
  3551 
  3552 * Pure: more efficient orders for basic syntactic entities: added
  3553 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3554 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3555 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3556 orders now -- potential INCOMPATIBILITY for code that depends on a
  3557 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3558 Library.sort_strings on result).
  3559 
  3560 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3561 fold_types traverse types/terms from left to right, observing natural
  3562 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3563 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3564 
  3565 * Pure: name spaces have been refined, with significant changes of the
  3566 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3567 to extern(_table).  The plain name entry path is superceded by a
  3568 general 'naming' context, which also includes the 'policy' to produce
  3569 a fully qualified name and external accesses of a fully qualified
  3570 name; NameSpace.extend is superceded by context dependent
  3571 Sign.declare_name.  Several theory and proof context operations modify
  3572 the naming context.  Especially note Theory.restore_naming and
  3573 ProofContext.restore_naming to get back to a sane state; note that
  3574 Theory.add_path is no longer sufficient to recover from
  3575 Theory.absolute_path in particular.
  3576 
  3577 * Pure: new flags short_names (default false) and unique_names
  3578 (default true) for controlling output of qualified names.  If
  3579 short_names is set, names are printed unqualified.  If unique_names is
  3580 reset, the name prefix is reduced to the minimum required to achieve
  3581 the original result when interning again, even if there is an overlap
  3582 with earlier declarations.
  3583 
  3584 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3585 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3586 (useful for printing error messages).  INCOMPATIBILITY.
  3587 
  3588 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3589 Theory.theory are now identified, referring to the universal
  3590 Context.theory (see Pure/context.ML).  Actual signature and theory
  3591 content is managed as theory data.  The old code and interfaces were
  3592 spread over many files and structures; the new arrangement introduces
  3593 considerable INCOMPATIBILITY to gain more clarity:
  3594 
  3595   Context -- theory management operations (name, identity, inclusion,
  3596     parents, ancestors, merge, etc.), plus generic theory data;
  3597 
  3598   Sign -- logical signature and syntax operations (declaring consts,
  3599     types, etc.), plus certify/read for common entities;
  3600 
  3601   Theory -- logical theory operations (stating axioms, definitions,
  3602     oracles), plus a copy of logical signature operations (consts,
  3603     types, etc.); also a few basic management operations (Theory.copy,
  3604     Theory.merge, etc.)
  3605 
  3606 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3607 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3608 for convenience -- they merely return the theory.
  3609 
  3610 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3611 
  3612 * Pure: the Isar proof context type is already defined early in Pure
  3613 as Context.proof (note that ProofContext.context and Proof.context are
  3614 aliases, where the latter is the preferred name).  This enables other
  3615 Isabelle components to refer to that type even before Isar is present.
  3616 
  3617 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3618 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3619 any of these kinds.  For example, Sign.intern typeK is now
  3620 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3621 Theory.hide_types.  Also note that former
  3622 Theory.hide_classes/types/consts are now
  3623 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3624 internalize their arguments!  INCOMPATIBILITY.
  3625 
  3626 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3627 datatype thmref (with constructors Name and NameSelection) instead of
  3628 plain string -- INCOMPATIBILITY;
  3629 
  3630 * Pure: cases produced by proof methods specify options, where NONE
  3631 means to remove case bindings -- INCOMPATIBILITY in
  3632 (RAW_)METHOD_CASES.
  3633 
  3634 * Pure: the following operations retrieve axioms or theorems from a
  3635 theory node or theory hierarchy, respectively:
  3636 
  3637   Theory.axioms_of: theory -> (string * term) list
  3638   Theory.all_axioms_of: theory -> (string * term) list
  3639   PureThy.thms_of: theory -> (string * thm) list
  3640   PureThy.all_thms_of: theory -> (string * thm) list
  3641 
  3642 * Pure: print_tac now outputs the goal through the trace channel.
  3643 
  3644 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3645 Reference Toplevel.debug (default false) controls detailed printing
  3646 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3647 controls execution profiling -- set to 1 for time and 2 for space
  3648 (both increase the runtime).
  3649 
  3650 * Isar session: The initial use of ROOT.ML is now always timed,
  3651 i.e. the log will show the actual process times, in contrast to the
  3652 elapsed wall-clock time that the outer shell wrapper produces.
  3653 
  3654 * Simplifier: improved handling of bound variables (nameless
  3655 representation, avoid allocating new strings).  Simprocs that invoke
  3656 the Simplifier recursively should use Simplifier.inherit_bounds to
  3657 avoid local name clashes.  Failure to do so produces warnings
  3658 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3659 for further details.
  3660 
  3661 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3662 bindings for all theorems stored within a given theory; this may help
  3663 in porting non-Isar theories to Isar ones, while keeping ML proof
  3664 scripts for the time being.
  3665 
  3666 * ML operator HTML.with_charset specifies the charset begin used for
  3667 generated HTML files.  For example:
  3668 
  3669   HTML.with_charset "utf-8" use_thy "Hebrew";
  3670   HTML.with_charset "utf-8" use_thy "Chinese";
  3671 
  3672 
  3673 *** System ***
  3674 
  3675 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3676 isabelle, isatool etc.).
  3677 
  3678 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3679 isatool doc, isatool mkdir, display_drafts etc.).
  3680 
  3681 * isatool usedir: option -f allows specification of the ML file to be
  3682 used by Isabelle; default is ROOT.ML.
  3683 
  3684 * New isatool version outputs the version identifier of the Isabelle
  3685 distribution being used.
  3686 
  3687 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3688 (containing Boolean satisfiability problems) into Isabelle/HOL
  3689 theories.
  3690 
  3691 
  3692 
  3693 New in Isabelle2004 (April 2004)
  3694 --------------------------------
  3695 
  3696 *** General ***
  3697 
  3698 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3699   Replaces linorder.ML.
  3700 
  3701 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3702   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3703   (\<a>...\<z>), are now considered normal letters, and can therefore
  3704   be used anywhere where an ASCII letter (a...zA...Z) has until
  3705   now. COMPATIBILITY: This obviously changes the parsing of some
  3706   terms, especially where a symbol has been used as a binder, say
  3707   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3708   as an identifier.  Fix it by inserting a space around former
  3709   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3710   existing theory and ML files.
  3711 
  3712 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3713 
  3714 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3715   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3716   a normal (but invisible) letter. For multiple letter subscripts repeat
  3717   \<^isub> like this: x\<^isub>1\<^isub>2.
  3718 
  3719 * Pure: There are now sub-/superscripts that can span more than one
  3720   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3721   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3722   superscript. The new control characters are not identifier parts.
  3723 
  3724 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3725   content of "..." to the latex file instead of \isacntrl... . The "..."
  3726   may consist of any printable characters excluding the end bracket >.
  3727 
  3728 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3729   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3730   declare constants "final", which prevents their being given a definition
  3731   later.  It is useful for constants whose behaviour is fixed axiomatically
  3732   rather than definitionally, such as the meta-logic connectives.
  3733 
  3734 * Pure: 'instance' now handles general arities with general sorts
  3735   (i.e. intersections of classes),
  3736 
  3737 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3738   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3739   It can be changed to alter the colors/layout of generated pages.
  3740 
  3741 
  3742 *** Isar ***
  3743 
  3744 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3745   cut_tac, subgoal_tac and thin_tac:
  3746   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3747     locales are no longer forced to write Isar proof scripts.
  3748     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3749     emulations.
  3750   - INCOMPATIBILITY: names of variables to be instantiated may no
  3751     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3752     This is consistent with the instantiation attribute "where".
  3753 
  3754 * Attributes "where" and "of":
  3755   - Now take type variables of instantiated theorem into account when reading
  3756     the instantiation string.  This fixes a bug that caused instantiated
  3757     theorems to have too special types in some circumstances.
  3758   - "where" permits explicit instantiations of type variables.
  3759 
  3760 * Calculation commands "moreover" and "also" no longer interfere with
  3761   current facts ("this"), admitting arbitrary combinations with "then"
  3762   and derived forms.
  3763 
  3764 * Locales:
  3765   - Goal statements involving the context element "includes" no longer
  3766     generate theorems with internal delta predicates (those ending on
  3767     "_axioms") in the premise.
  3768     Resolve particular premise with <locale>.intro to obtain old form.
  3769   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3770     specification and "includes" elements in goal statement.
  3771   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3772     [intro?] and [elim?] (respectively) by default.
  3773   - Experimental command for instantiation of locales in proof contexts:
  3774         instantiate <label>[<attrs>]: <loc>
  3775     Instantiates locale <loc> and adds all its theorems to the current context
  3776     taking into account their attributes.  Label and attrs are optional
  3777     modifiers, like in theorem declarations.  If present, names of
  3778     instantiated theorems are qualified with <label>, and the attributes
  3779     <attrs> are applied after any attributes these theorems might have already.
  3780       If the locale has assumptions, a chained fact of the form
  3781     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3782     are derived.  The command does not support old-style locales declared
  3783     with "locale (open)".
  3784       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3785 
  3786 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3787   (Isar) contexts.
  3788 
  3789 
  3790 *** HOL ***
  3791 
  3792 * Proof import: new image HOL4 contains the imported library from
  3793   the HOL4 system with about 2500 theorems. It is imported by
  3794   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3795   can be used like any other Isabelle image.  See
  3796   HOL/Import/HOL/README for more information.
  3797 
  3798 * Simplifier:
  3799   - Much improved handling of linear and partial orders.
  3800     Reasoners for linear and partial orders are set up for type classes
  3801     "linorder" and "order" respectively, and are added to the default simpset
  3802     as solvers.  This means that the simplifier can build transitivity chains
  3803     to solve goals from the assumptions.
  3804   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3805     of blast or auto after simplification become unnecessary because the goal
  3806     is solved by simplification already.
  3807 
  3808 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3809     all proved in axiomatic type classes for semirings, rings and fields.
  3810 
  3811 * Numerics:
  3812   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3813     now formalized using the Ring_and_Field theory mentioned above.
  3814   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3815     than before, because now they are set up once in a generic manner.
  3816   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3817     Look for the general versions in Ring_and_Field (and Power if they concern
  3818     exponentiation).
  3819 
  3820 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3821 
  3822 * Records:
  3823   - Record types are now by default printed with their type abbreviation
  3824     instead of the list of all field types. This can be configured via
  3825     the reference "print_record_type_abbr".
  3826   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3827     (not enabled by default).
  3828   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3829     EX x. x = sel r to True (not enabled by default).
  3830   - Tactic "record_split_simp_tac" to split and simplify records added.
  3831 
  3832 * 'specification' command added, allowing for definition by
  3833   specification.  There is also an 'ax_specification' command that
  3834   introduces the new constants axiomatically.
  3835 
  3836 * arith(_tac) is now able to generate counterexamples for reals as well.
  3837 
  3838 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3839 
  3840 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3841   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3842 
  3843 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3844   matrix theory to linear programming.
  3845 
  3846 * Unions and Intersections:
  3847   The latex output syntax of UN and INT has been changed
  3848   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3849   i.e. the index formulae has become a subscript.
  3850   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3851 
  3852 * Unions and Intersections over Intervals:
  3853   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3854   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3855   like in normal math, and corresponding versions for < and for intersection.
  3856 
  3857 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3858   lexicographic dictonary ordering has been added as "lexord".
  3859 
  3860 * ML: the legacy theory structures Int and List have been removed. They had
  3861   conflicted with ML Basis Library structures having the same names.
  3862 
  3863 * 'refute' command added to search for (finite) countermodels.  Only works
  3864   for a fragment of HOL.  The installation of an external SAT solver is
  3865   highly recommended.  See "HOL/Refute.thy" for details.
  3866 
  3867 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3868   formulae under an assignment of free variables to random values.
  3869   In contrast to 'refute', it can deal with inductive datatypes,
  3870   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3871   for examples.
  3872 
  3873 
  3874 *** HOLCF ***
  3875 
  3876 * Streams now come with concatenation and are part of the HOLCF image
  3877 
  3878 
  3879 
  3880 New in Isabelle2003 (May 2003)
  3881 ------------------------------
  3882 
  3883 *** General ***
  3884 
  3885 * Provers/simplifier:
  3886 
  3887   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3888     Assumptions are now subject to complete mutual simplification,
  3889     not just from left to right. The simplifier now preserves
  3890     the order of assumptions.
  3891 
  3892     Potential INCOMPATIBILITY:
  3893 
  3894     -- simp sometimes diverges where the old version did
  3895        not, e.g. invoking simp on the goal
  3896 
  3897         [| P (f x); y = x; f x = f y |] ==> Q
  3898 
  3899        now gives rise to the infinite reduction sequence
  3900 
  3901         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3902 
  3903        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3904        kind of problem.
  3905 
  3906     -- Tactics combining classical reasoner and simplification (such as auto)
  3907        are also affected by this change, because many of them rely on
  3908        simp. They may sometimes diverge as well or yield a different numbers
  3909        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3910        in case of problems. Sometimes subsequent calls to the classical
  3911        reasoner will fail because a preceeding call to the simplifier too
  3912        eagerly simplified the goal, e.g. deleted redundant premises.
  3913 
  3914   - The simplifier trace now shows the names of the applied rewrite rules
  3915 
  3916   - You can limit the number of recursive invocations of the simplifier
  3917     during conditional rewriting (where the simplifie tries to solve the
  3918     conditions before applying the rewrite rule):
  3919     ML "simp_depth_limit := n"
  3920     where n is an integer. Thus you can force termination where previously
  3921     the simplifier would diverge.
  3922 
  3923   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3924 
  3925   - No longer aborts on failed congruence proof.  Instead, the
  3926     congruence is ignored.
  3927 
  3928 * Pure: New generic framework for extracting programs from constructive
  3929   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3930   as HOL/Extraction for some case studies.
  3931 
  3932 * Pure: The main goal of the proof state is no longer shown by default, only
  3933 the subgoals. This behaviour is controlled by a new flag.
  3934    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3935 (ML: Proof.show_main_goal).
  3936 
  3937 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3938 rules whose conclusion matches subgoal 1:
  3939       PG menu: Isabelle/Isar -> Show me -> matching rules
  3940 The rules are ordered by how closely they match the subgoal.
  3941 In particular, rules that solve a subgoal outright are displayed first
  3942 (or rather last, the way they are printed).
  3943 (ML: ProofGeneral.print_intros())
  3944 
  3945 * Pure: New flag trace_unify_fail causes unification to print
  3946 diagnostic information (PG: in trace buffer) when it fails. This is
  3947 useful for figuring out why single step proofs like rule, erule or
  3948 assumption failed.
  3949 
  3950 * Pure: Locale specifications now produce predicate definitions
  3951 according to the body of text (covering assumptions modulo local
  3952 definitions); predicate "loc_axioms" covers newly introduced text,
  3953 while "loc" is cumulative wrt. all included locale expressions; the
  3954 latter view is presented only on export into the global theory
  3955 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3956 on the old view without predicates;
  3957 
  3958 * Pure: predefined locales "var" and "struct" are useful for sharing
  3959 parameters (as in CASL, for example); just specify something like
  3960 ``var x + var y + struct M'' as import;
  3961 
  3962 * Pure: improved thms_containing: proper indexing of facts instead of
  3963 raw theorems; check validity of results wrt. current name space;
  3964 include local facts of proof configuration (also covers active
  3965 locales), cover fixed variables in index; may use "_" in term
  3966 specification; an optional limit for the number of printed facts may
  3967 be given (the default is 40);
  3968 
  3969 * Pure: disallow duplicate fact bindings within new-style theory files
  3970 (batch-mode only);
  3971 
  3972 * Provers: improved induct method: assumptions introduced by case
  3973 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3974 the goal statement); "foo" still refers to all facts collectively;
  3975 
  3976 * Provers: the function blast.overloaded has been removed: all constants
  3977 are regarded as potentially overloaded, which improves robustness in exchange
  3978 for slight decrease in efficiency;
  3979 
  3980 * Provers/linorder: New generic prover for transitivity reasoning over
  3981 linear orders.  Note: this prover is not efficient!
  3982 
  3983 * Isar: preview of problems to finish 'show' now produce an error
  3984 rather than just a warning (in interactive mode);
  3985 
  3986 
  3987 *** HOL ***
  3988 
  3989 * arith(_tac)
  3990 
  3991  - Produces a counter example if it cannot prove a goal.
  3992    Note that the counter example may be spurious if the goal is not a formula
  3993    of quantifier-free linear arithmetic.
  3994    In ProofGeneral the counter example appears in the trace buffer.
  3995 
  3996  - Knows about div k and mod k where k is a numeral of type nat or int.
  3997 
  3998  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3999    linear arithmetic fails. This takes account of quantifiers and divisibility.
  4000    Presburger arithmetic can also be called explicitly via presburger(_tac).
  4001 
  4002 * simp's arithmetic capabilities have been enhanced a bit: it now
  4003 takes ~= in premises into account (by performing a case split);
  4004 
  4005 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  4006 are distributed over a sum of terms;
  4007 
  4008 * New tactic "trans_tac" and method "trans" instantiate
  4009 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  4010 "<=", "<" and "=").
  4011 
  4012 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  4013 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  4014 
  4015 * 'typedef' command has new option "open" to suppress the set
  4016 definition;
  4017 
  4018 * functions Min and Max on finite sets have been introduced (theory
  4019 Finite_Set);
  4020 
  4021 * attribute [symmetric] now works for relations as well; it turns
  4022 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4023 
  4024 * induct over a !!-quantified statement (say !!x1..xn):
  4025   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4026 
  4027 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4028 %x. None. Warning: empty_def now refers to the previously hidden definition
  4029 of the empty set.
  4030 
  4031 * Algebra: formalization of classical algebra.  Intended as base for
  4032 any algebraic development in Isabelle.  Currently covers group theory
  4033 (up to Sylow's theorem) and ring theory (Universal Property of
  4034 Univariate Polynomials).  Contributions welcome;
  4035 
  4036 * GroupTheory: deleted, since its material has been moved to Algebra;
  4037 
  4038 * Complex: new directory of the complex numbers with numeric constants,
  4039 nonstandard complex numbers, and some complex analysis, standard and
  4040 nonstandard (Jacques Fleuriot);
  4041 
  4042 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4043 
  4044 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4045 Fleuriot);
  4046 
  4047 * Real/HahnBanach: updated and adapted to locales;
  4048 
  4049 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4050 Gray and Kramer);
  4051 
  4052 * UNITY: added the Meier-Sanders theory of progress sets;
  4053 
  4054 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4055 as abstract algorithms, instantiated to the JVM;
  4056 
  4057 * Bali: Java source language formalization. Type system, operational
  4058 semantics, axiomatic semantics. Supported language features:
  4059 classes, interfaces, objects,virtual methods, static methods,
  4060 static/instance fields, arrays, access modifiers, definite
  4061 assignment, exceptions.
  4062 
  4063 
  4064 *** ZF ***
  4065 
  4066 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4067 universe, etc.);
  4068 
  4069 * Main ZF: virtually all theories converted to new-style format;
  4070 
  4071 
  4072 *** ML ***
  4073 
  4074 * Pure: Tactic.prove provides sane interface for internal proofs;
  4075 omits the infamous "standard" operation, so this is more appropriate
  4076 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4077 
  4078 * Pure: improved error reporting of simprocs;
  4079 
  4080 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4081 up simprocs;
  4082 
  4083 
  4084 *** Document preparation ***
  4085 
  4086 * uses \par instead of \\ for line breaks in theory text. This may
  4087 shift some page breaks in large documents. To get the old behaviour
  4088 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4089 
  4090 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4091 other packages
  4092 
  4093 * \<euro> now needs package babel/greek instead of marvosym (which
  4094 broke \Rightarrow)
  4095 
  4096 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4097 textcomp package)
  4098 
  4099 
  4100 
  4101 New in Isabelle2002 (March 2002)
  4102 --------------------------------
  4103 
  4104 *** Document preparation ***
  4105 
  4106 * greatly simplified document preparation setup, including more
  4107 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4108 instructive isatool mkdir; users should basically be able to get
  4109 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4110 users may run a separate document processing stage manually like this:
  4111 "isatool usedir -D output HOL Test && isatool document Test/output";
  4112 
  4113 * theory dependency graph may now be incorporated into documents;
  4114 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4115 with \includegraphics of LaTeX;
  4116 
  4117 * proper spacing of consecutive markup elements, especially text
  4118 blocks after section headings;
  4119 
  4120 * support bold style (for single symbols only), input syntax is like
  4121 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4122 
  4123 * \<bullet> is now output as bold \cdot by default, which looks much
  4124 better in printed text;
  4125 
  4126 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4127 note that these symbols are currently unavailable in Proof General /
  4128 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4129 
  4130 * isatool latex no longer depends on changed TEXINPUTS, instead
  4131 isatool document copies the Isabelle style files to the target
  4132 location;
  4133 
  4134 
  4135 *** Isar ***
  4136 
  4137 * Pure/Provers: improved proof by cases and induction;
  4138   - 'case' command admits impromptu naming of parameters (such as
  4139     "case (Suc n)");
  4140   - 'induct' method divinates rule instantiation from the inductive
  4141     claim; no longer requires excessive ?P bindings for proper
  4142     instantiation of cases;
  4143   - 'induct' method properly enumerates all possibilities of set/type
  4144     rules; as a consequence facts may be also passed through *type*
  4145     rules without further ado;
  4146   - 'induct' method now derives symbolic cases from the *rulified*
  4147     rule (before it used to rulify cases stemming from the internal
  4148     atomized version); this means that the context of a non-atomic
  4149     statement becomes is included in the hypothesis, avoiding the
  4150     slightly cumbersome show "PROP ?case" form;
  4151   - 'induct' may now use elim-style induction rules without chaining
  4152     facts, using ``missing'' premises from the goal state; this allows
  4153     rules stemming from inductive sets to be applied in unstructured
  4154     scripts, while still benefitting from proper handling of non-atomic
  4155     statements; NB: major inductive premises need to be put first, all
  4156     the rest of the goal is passed through the induction;
  4157   - 'induct' proper support for mutual induction involving non-atomic
  4158     rule statements (uses the new concept of simultaneous goals, see
  4159     below);
  4160   - append all possible rule selections, but only use the first
  4161     success (no backtracking);
  4162   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4163   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4164   - added 'print_induct_rules' (covered by help item in recent Proof
  4165     General versions);
  4166   - moved induct/cases attributes to Pure, methods to Provers;
  4167   - generic method setup instantiated for FOL and HOL;
  4168 
  4169 * Pure: support multiple simultaneous goal statements, for example
  4170 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4171 meta-level mechanism, this acts as if several individual goals had
  4172 been stated separately; in particular common proof methods need to be
  4173 repeated in order to cover all claims; note that a single elimination
  4174 step is *not* sufficient to establish the two conjunctions, so this
  4175 fails:
  4176 
  4177   assume "A & B" then have A and B ..   (*".." fails*)
  4178 
  4179 better use "obtain" in situations as above; alternative refer to
  4180 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4181 
  4182 * Pure: proper integration with ``locales''; unlike the original
  4183 version by Florian Kammller, Isar locales package high-level proof
  4184 contexts rather than raw logical ones (e.g. we admit to include
  4185 attributes everywhere); operations on locales include merge and
  4186 rename; support for implicit arguments (``structures''); simultaneous
  4187 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4188 some examples;
  4189 
  4190 * Pure: the following commands have been ``localized'', supporting a
  4191 target locale specification "(in name)": 'lemma', 'theorem',
  4192 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4193 stored both within the locale and at the theory level (exported and
  4194 qualified by the locale name);
  4195 
  4196 * Pure: theory goals may now be specified in ``long'' form, with
  4197 ad-hoc contexts consisting of arbitrary locale elements. for example
  4198 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4199 definitions may be given, too); the result is a meta-level rule with
  4200 the context elements being discharged in the obvious way;
  4201 
  4202 * Pure: new proof command 'using' allows to augment currently used
  4203 facts after a goal statement ('using' is syntactically analogous to
  4204 'apply', but acts on the goal's facts only); this allows chained facts
  4205 to be separated into parts given before and after a claim, as in
  4206 ``from a and b have C using d and e <proof>'';
  4207 
  4208 * Pure: renamed "antecedent" case to "rule_context";
  4209 
  4210 * Pure: new 'judgment' command records explicit information about the
  4211 object-logic embedding (used by several tools internally); no longer
  4212 use hard-wired "Trueprop";
  4213 
  4214 * Pure: added 'corollary' command;
  4215 
  4216 * Pure: fixed 'token_translation' command;
  4217 
  4218 * Pure: removed obsolete 'exported' attribute;
  4219 
  4220 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4221 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4222 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4223 
  4224 * Pure: method 'atomize' presents local goal premises as object-level
  4225 statements (atomic meta-level propositions); setup controlled via
  4226 rewrite rules declarations of 'atomize' attribute; example
  4227 application: 'induct' method with proper rule statements in improper
  4228 proof *scripts*;
  4229 
  4230 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4231 now consider the syntactic context of assumptions, giving a better
  4232 chance to get type-inference of the arguments right (this is
  4233 especially important for locales);
  4234 
  4235 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4236 mode;
  4237 
  4238 * Pure/obtain: the formal conclusion "thesis", being marked as
  4239 ``internal'', may no longer be reference directly in the text;
  4240 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4241 situations;
  4242 
  4243 * Pure: generic 'sym' attribute which declares a rule both as pure
  4244 'elim?' and for the 'symmetric' operation;
  4245 
  4246 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4247 text; the fixed correlation with particular command syntax has been
  4248 discontinued;
  4249 
  4250 * Pure: new method 'rules' is particularly well-suited for proof
  4251 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4252 but often produces more compact proof terms with less detours;
  4253 
  4254 * Pure/Provers/classical: simplified integration with pure rule
  4255 attributes and methods; the classical "intro?/elim?/dest?"
  4256 declarations coincide with the pure ones; the "rule" method no longer
  4257 includes classically swapped intros; "intro" and "elim" methods no
  4258 longer pick rules from the context; also got rid of ML declarations
  4259 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4260 INCOMPATIBILITY;
  4261 
  4262 * Provers/classical: attribute 'swapped' produces classical inversions
  4263 of introduction rules;
  4264 
  4265 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4266 rules instead of full simplifier context; 'iff' attribute handles
  4267 conditional rules;
  4268 
  4269 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4270 
  4271 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4272 "(permissive)" option to recover old behavior;
  4273 
  4274 * HOL: 'inductive' no longer features separate (collective) attributes
  4275 for 'intros' (was found too confusing);
  4276 
  4277 * HOL: properly declared induction rules less_induct and
  4278 wf_induct_rule;
  4279 
  4280 
  4281 *** HOL ***
  4282 
  4283 * HOL: moved over to sane numeral syntax; the new policy is as
  4284 follows:
  4285 
  4286   - 0 and 1 are polymorphic constants, which are defined on any
  4287   numeric type (nat, int, real etc.);
  4288 
  4289   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4290   binary representation internally;
  4291 
  4292   - type nat has special constructor Suc, and generally prefers Suc 0
  4293   over 1::nat and Suc (Suc 0) over 2::nat;
  4294 
  4295 This change may cause significant problems of INCOMPATIBILITY; here
  4296 are some hints on converting existing sources:
  4297 
  4298   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4299   entities, so expressions involving "-" (unary or binary minus) need
  4300   to be spaced properly;
  4301 
  4302   - existing occurrences of "1" may need to be constraint "1::nat" or
  4303   even replaced by Suc 0; similar for old "2";
  4304 
  4305   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4306 
  4307   - remove all special provisions on numerals in proofs;
  4308 
  4309 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4310 representation (depends on bin_arith_simps in the default context);
  4311 
  4312 * HOL: symbolic syntax for x^2 (numeral 2);
  4313 
  4314 * HOL: the class of all HOL types is now called "type" rather than
  4315 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4316 in axclass/classes, instance/arities, and (usually rare) occurrences
  4317 in typings (of consts etc.); internally the class is called
  4318 "HOL.type", ML programs should refer to HOLogic.typeS;
  4319 
  4320 * HOL/record package improvements:
  4321   - new derived operations "fields" to build a partial record section,
  4322     "extend" to promote a fixed record to a record scheme, and
  4323     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4324     declared as simp by default;
  4325   - shared operations ("more", "fields", etc.) now need to be always
  4326     qualified) --- potential INCOMPATIBILITY;
  4327   - removed "make_scheme" operations (use "make" with "extend") --
  4328     INCOMPATIBILITY;
  4329   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4330   - provides cases/induct rules for use with corresponding Isar
  4331     methods (for concrete records, record schemes, concrete more
  4332     parts, and schematic more parts -- in that order);
  4333   - internal definitions directly based on a light-weight abstract
  4334     theory of product types over typedef rather than datatype;
  4335 
  4336 * HOL: generic code generator for generating executable ML code from
  4337 specifications; specific support for HOL constructs such as inductive
  4338 datatypes and sets, as well as recursive functions; can be invoked
  4339 via 'generate_code' theory section;
  4340 
  4341 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4342 
  4343 * HOL: consolidated and renamed several theories.  In particular:
  4344         Ord.thy has been absorbed into HOL.thy
  4345         String.thy has been absorbed into List.thy
  4346 
  4347 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4348 (beware of argument permutation!);
  4349 
  4350 * HOL: linorder_less_split superseded by linorder_cases;
  4351 
  4352 * HOL/List: "nodups" renamed to "distinct";
  4353 
  4354 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4355 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4356   - Ex_def has changed, now need to use some_eq_ex
  4357 
  4358 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4359 in this (rare) case use:
  4360 
  4361   delSWrapper "split_all_tac"
  4362   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4363 
  4364 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4365 MAY FAIL;
  4366 
  4367 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4368 Isabelle's type classes, ^ on functions and relations has too general
  4369 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4370 necessary to attach explicit type constraints;
  4371 
  4372 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4373 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4374 renamed accordingly (eg "compI" -> "rel_compI").
  4375 
  4376 * HOL: syntax translations now work properly with numerals and records
  4377 expressions;
  4378 
  4379 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4380 of "lam" -- INCOMPATIBILITY;
  4381 
  4382 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4383 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4384 renamed "Product_Type.unit";
  4385 
  4386 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4387 
  4388 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4389 the "cases" method);
  4390 
  4391 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4392 Florian Kammller);
  4393 
  4394 * HOL/IMP: updated and converted to new-style theory format; several
  4395 parts turned into readable document, with proper Isar proof texts and
  4396 some explanations (by Gerwin Klein);
  4397 
  4398 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4399 
  4400 * HOL-Hyperreal is now a logic image;
  4401 
  4402 
  4403 *** HOLCF ***
  4404 
  4405 * Isar: consts/constdefs supports mixfix syntax for continuous
  4406 operations;
  4407 
  4408 * Isar: domain package adapted to new-style theory format, e.g. see
  4409 HOLCF/ex/Dnat.thy;
  4410 
  4411 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4412 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4413 lift.induct_tac, always use UU instead of Undef;
  4414 
  4415 * HOLCF/IMP: updated and converted to new-style theory;
  4416 
  4417 
  4418 *** ZF ***
  4419 
  4420 * Isar: proper integration of logic-specific tools and packages,
  4421 including theory commands '(co)inductive', '(co)datatype',
  4422 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4423 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4424 
  4425 * theory Main no longer includes AC; for the Axiom of Choice, base
  4426 your theory on Main_ZFC;
  4427 
  4428 * the integer library now covers quotients and remainders, with many
  4429 laws relating division to addition, multiplication, etc.;
  4430 
  4431 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4432 typeless version of the formalism;
  4433 
  4434 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4435 format;
  4436 
  4437 * ZF/Induct: new directory for examples of inductive definitions,
  4438 including theory Multiset for multiset orderings; converted to
  4439 new-style theory format;
  4440 
  4441 * ZF: many new theorems about lists, ordinals, etc.;
  4442 
  4443 
  4444 *** General ***
  4445 
  4446 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4447 variable proof controls level of detail: 0 = no proofs (only oracle
  4448 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4449 also ref manual for further ML interfaces;
  4450 
  4451 * Pure/axclass: removed obsolete ML interface
  4452 goal_subclass/goal_arity;
  4453 
  4454 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4455 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4456 separate tokens, so expressions involving minus need to be spaced
  4457 properly;
  4458 
  4459 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4460 rather than "infixl" or "infixr";
  4461 
  4462 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4463 sort constraint specifications in type inference; e.g. "x::_::foo"
  4464 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4465 type variable);
  4466 
  4467 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4468 control output of nested => (types); the default behavior is
  4469 "type_brackets";
  4470 
  4471 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4472 tokens into AST constants;
  4473 
  4474 * Pure/syntax: prefer later declarations of translations and print
  4475 translation functions; potential INCOMPATIBILITY: need to reverse
  4476 multiple declarations for same syntax element constant;
  4477 
  4478 * Pure/show_hyps reset by default (in accordance to existing Isar
  4479 practice);
  4480 
  4481 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4482 addSafter;
  4483 
  4484 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4485 as well;
  4486 
  4487 * system: tested support for MacOS X; should be able to get Isabelle +
  4488 Proof General to work in a plain Terminal after installing Poly/ML
  4489 (e.g. from the Isabelle distribution area) and GNU bash alone
  4490 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4491 support requires further installations, e.g. from
  4492 http://fink.sourceforge.net/);
  4493 
  4494 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4495 
  4496 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4497 of 40 MB), cf. ML_OPTIONS;
  4498 
  4499 * system: Proof General keywords specification is now part of the
  4500 Isabelle distribution (see etc/isar-keywords.el);
  4501 
  4502 * system: support for persistent Proof General sessions (refrain from
  4503 outdating all loaded theories on startup); user may create writable
  4504 logic images like this: ``isabelle -q HOL Test'';
  4505 
  4506 * system: smart selection of Isabelle process versus Isabelle
  4507 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4508 run both "isabelle" and "Isabelle" even if file names are badly
  4509 damaged (executable inspects the case of the first letter of its own
  4510 name); added separate "isabelle-process" and "isabelle-interface";
  4511 
  4512 * system: refrain from any attempt at filtering input streams; no
  4513 longer support ``8bit'' encoding of old isabelle font, instead proper
  4514 iso-latin characters may now be used; the related isatools
  4515 "symbolinput" and "nonascii" have disappeared as well;
  4516 
  4517 * system: removed old "xterm" interface (the print modes "xterm" and
  4518 "xterm_color" are still available for direct use in a suitable
  4519 terminal);
  4520 
  4521 
  4522 
  4523 New in Isabelle99-2 (February 2001)
  4524 -----------------------------------
  4525 
  4526 *** Overview of INCOMPATIBILITIES ***
  4527 
  4528 * HOL: please note that theories in the Library and elsewhere often use the
  4529 new-style (Isar) format; to refer to their theorems in an ML script you must
  4530 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4531 
  4532 * HOL: inductive package no longer splits induction rule aggressively,
  4533 but only as far as specified by the introductions given; the old
  4534 format may be recovered via ML function complete_split_rule or attribute
  4535 'split_rule (complete)';
  4536 
  4537 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4538 gfp_Tarski to gfp_unfold;
  4539 
  4540 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4541 
  4542 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4543 relation); infix "^^" has been renamed "``"; infix "``" has been
  4544 renamed "`"; "univalent" has been renamed "single_valued";
  4545 
  4546 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4547 operation;
  4548 
  4549 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4550 
  4551 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4552 
  4553 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4554 consequence, it is no longer monotonic wrt. the local goal context
  4555 (which is now passed through the inductive cases);
  4556 
  4557 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4558 \<gg> to \<ggreater>;
  4559 
  4560 
  4561 *** Document preparation ***
  4562 
  4563 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4564 available: are "it" for near math-mode best-style output, "sl" for
  4565 slanted text style, and "tt" for plain type-writer; if no
  4566 \isabellestyle command is given, output is according to slanted
  4567 type-writer);
  4568 
  4569 * support sub/super scripts (for single symbols only), input syntax is
  4570 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4571 
  4572 * some more standard symbols; see Appendix A of the system manual for
  4573 the complete list of symbols defined in isabellesym.sty;
  4574 
  4575 * improved isabelle style files; more abstract symbol implementation
  4576 (should now use \isamath{...} and \isatext{...} in custom symbol
  4577 definitions);
  4578 
  4579 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4580 state; Note that presentation of goal states does not conform to
  4581 actual human-readable proof documents.  Please do not include goal
  4582 states into document output unless you really know what you are doing!
  4583 
  4584 * proper indentation of antiquoted output with proportional LaTeX
  4585 fonts;
  4586 
  4587 * no_document ML operator temporarily disables LaTeX document
  4588 generation;
  4589 
  4590 * isatool unsymbolize tunes sources for plain ASCII communication;
  4591 
  4592 
  4593 *** Isar ***
  4594 
  4595 * Pure: Isar now suffers initial goal statements to contain unbound
  4596 schematic variables (this does not conform to actual readable proof
  4597 documents, due to unpredictable outcome and non-compositional proof
  4598 checking); users who know what they are doing may use schematic goals
  4599 for Prolog-style synthesis of proven results;
  4600 
  4601 * Pure: assumption method (an implicit finishing) now handles actual
  4602 rules as well;
  4603 
  4604 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4605 initial goal, declare "that" only as Pure intro (only for single
  4606 steps); the "that" rule assumption may now be involved in implicit
  4607 finishing, thus ".." becomes a feasible for trivial obtains;
  4608 
  4609 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4610 instance proofs may be performed by "..";
  4611 
  4612 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4613 statements as well;
  4614 
  4615 * Pure: more robust selection of calculational rules;
  4616 
  4617 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4618 rule (as well as the assumption rule);
  4619 
  4620 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4621 lemmas, using the graph browser tool;
  4622 
  4623 * Pure: predict failure of "show" in interactive mode;
  4624 
  4625 * Pure: 'thms_containing' now takes actual terms as arguments;
  4626 
  4627 * HOL: improved method 'induct' --- now handles non-atomic goals
  4628 (potential INCOMPATIBILITY); tuned error handling;
  4629 
  4630 * HOL: cases and induct rules now provide explicit hints about the
  4631 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4632 any remaining facts are inserted into the goal verbatim;
  4633 
  4634 * HOL: local contexts (aka cases) may now contain term bindings as
  4635 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4636 the result to be shown in each case;
  4637 
  4638 * HOL: added 'recdef_tc' command;
  4639 
  4640 * isatool convert assists in eliminating legacy ML scripts;
  4641 
  4642 
  4643 *** HOL ***
  4644 
  4645 * HOL/Library: a collection of generic theories to be used together
  4646 with main HOL; the theory loader path already includes this directory
  4647 by default; the following existing theories have been moved here:
  4648 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4649 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4650 
  4651 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4652 modelling and verification task performed in Isabelle/HOL +
  4653 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4654 
  4655 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4656 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4657 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4658 'domain', this makes the theory consistent with mathematical
  4659 literature;
  4660 
  4661 * HOL basics: added overloaded operations "inverse" and "divide"
  4662 (infix "/"), syntax for generic "abs" operation, generic summation
  4663 operator \<Sum>;
  4664 
  4665 * HOL/typedef: simplified package, provide more useful rules (see also
  4666 HOL/subset.thy);
  4667 
  4668 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4669 now expressed as a proper nested rule (old-style tactic scripts may
  4670 require atomize_strip_tac to cope with non-atomic premises);
  4671 
  4672 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4673 to "split_conv" (old name still available for compatibility);
  4674 
  4675 * HOL: improved concrete syntax for strings (e.g. allows translation
  4676 rules with string literals);
  4677 
  4678 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4679  and Fleuriot's mechanization of analysis, including the transcendental
  4680  functions for the reals;
  4681 
  4682 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4683 
  4684 
  4685 *** CTT ***
  4686 
  4687 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4688 "lam" is displayed as TWO lambda-symbols
  4689 
  4690 * CTT: theory Main now available, containing everything (that is, Bool
  4691 and Arith);
  4692 
  4693 
  4694 *** General ***
  4695 
  4696 * Pure: the Simplifier has been implemented properly as a derived rule
  4697 outside of the actual kernel (at last!); the overall performance
  4698 penalty in practical applications is about 50%, while reliability of
  4699 the Isabelle inference kernel has been greatly improved;
  4700 
  4701 * print modes "brackets" and "no_brackets" control output of nested =>
  4702 (types) and ==> (props); the default behaviour is "brackets";
  4703 
  4704 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4705 as assumptions as well;
  4706 
  4707 * system: support Poly/ML 4.0;
  4708 
  4709 * system: isatool install handles KDE version 1 or 2;
  4710 
  4711 
  4712 
  4713 New in Isabelle99-1 (October 2000)
  4714 ----------------------------------
  4715 
  4716 *** Overview of INCOMPATIBILITIES ***
  4717 
  4718 * HOL: simplification of natural numbers is much changed; to partly
  4719 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4720 issue the following ML commands:
  4721 
  4722   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4723   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4724 
  4725 * HOL: simplification no longer dives into case-expressions; this is
  4726 controlled by "t.weak_case_cong" for each datatype t;
  4727 
  4728 * HOL: nat_less_induct renamed to less_induct;
  4729 
  4730 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4731 fixsome to patch .thy and .ML sources automatically;
  4732 
  4733   select_equality  -> some_equality
  4734   select_eq_Ex     -> some_eq_ex
  4735   selectI2EX       -> someI2_ex
  4736   selectI2         -> someI2
  4737   selectI          -> someI
  4738   select1_equality -> some1_equality
  4739   Eps_sym_eq       -> some_sym_eq_trivial
  4740   Eps_eq           -> some_eq_trivial
  4741 
  4742 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4743 
  4744 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4745 instead);
  4746 
  4747 * HOL: the recursion equations generated by 'recdef' are now called
  4748 f.simps instead of f.rules;
  4749 
  4750 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4751 
  4752 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4753 sometimes be needed;
  4754 
  4755 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4756 
  4757 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4758 
  4759 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4760 product is now "<*>" instead of "Times"; the lexicographic product is
  4761 now "<*lex*>" instead of "**";
  4762 
  4763 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4764 of main HOL, but was unused); better use HOL's datatype package;
  4765 
  4766 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4767 the old syntax may be recovered as follows:
  4768 
  4769   syntax (symbols)
  4770     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4771       (infixl "\\<oplus>" 100)
  4772 
  4773 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4774 
  4775 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4776 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4777 internally;
  4778 
  4779 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4780 changed from A/r to A//r;
  4781 
  4782 * ZF: new treatment of arithmetic (nat & int) may break some old
  4783 proofs;
  4784 
  4785 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4786 rulify -> rule_format, elimify -> elim_format, ...);
  4787 
  4788 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4789 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4790 should have to change intro!! to intro? only); replaced "delrule" by
  4791 "rule del";
  4792 
  4793 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4794 
  4795 * Provers: strengthened force_tac by using new first_best_tac;
  4796 
  4797 * LaTeX document preparation: several changes of isabelle.sty (see
  4798 lib/texinputs);
  4799 
  4800 
  4801 *** Document preparation ***
  4802 
  4803 * formal comments (text blocks etc.) in new-style theories may now
  4804 contain antiquotations of thm/prop/term/typ/text to be presented
  4805 according to latex print mode; concrete syntax is like this:
  4806 @{term[show_types] "f(x) = a + x"};
  4807 
  4808 * isatool mkdir provides easy setup of Isabelle session directories,
  4809 including proper document sources;
  4810 
  4811 * generated LaTeX sources are now deleted after successful run
  4812 (isatool document -c); may retain a copy somewhere else via -D option
  4813 of isatool usedir;
  4814 
  4815 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4816 style files, achieving self-contained LaTeX sources and simplifying
  4817 LaTeX debugging;
  4818 
  4819 * old-style theories now produce (crude) LaTeX output as well;
  4820 
  4821 * browser info session directories are now self-contained (may be put
  4822 on WWW server seperately); improved graphs of nested sessions; removed
  4823 graph for 'all sessions';
  4824 
  4825 * several improvements in isabelle style files; \isabellestyle{it}
  4826 produces fake math mode output; \isamarkupheader is now \section by
  4827 default; see lib/texinputs/isabelle.sty etc.;
  4828 
  4829 
  4830 *** Isar ***
  4831 
  4832 * Isar/Pure: local results and corresponding term bindings are now
  4833 subject to Hindley-Milner polymorphism (similar to ML); this
  4834 accommodates incremental type-inference very nicely;
  4835 
  4836 * Isar/Pure: new derived language element 'obtain' supports
  4837 generalized existence reasoning;
  4838 
  4839 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4840 support accumulation of results, without applying any rules yet;
  4841 useful to collect intermediate results without explicit name
  4842 references, and for use with transitivity rules with more than 2
  4843 premises;
  4844 
  4845 * Isar/Pure: scalable support for case-analysis type proofs: new
  4846 'case' language element refers to local contexts symbolically, as
  4847 produced by certain proof methods; internally, case names are attached
  4848 to theorems as "tags";
  4849 
  4850 * Isar/Pure: theory command 'hide' removes declarations from
  4851 class/type/const name spaces;
  4852 
  4853 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4854 indicate potential overloading;
  4855 
  4856 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4857 
  4858 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4859 "{a,b,c}" instead of {a,b,c};
  4860 
  4861 * Isar/Pure now provides its own version of intro/elim/dest
  4862 attributes; useful for building new logics, but beware of confusion
  4863 with the version in Provers/classical;
  4864 
  4865 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4866 case name 'antecedent';
  4867 
  4868 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4869 to the current context is now done automatically);
  4870 
  4871 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4872 for definining proof methods in ML;
  4873 
  4874 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4875 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4876 most cases, one should have to change intro!! to intro? only);
  4877 replaced "delrule" by "rule del";
  4878 
  4879 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4880 'symmetric' attribute (the latter supercedes [RS sym]);
  4881 
  4882 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4883 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4884 well (including splits);
  4885 
  4886 * Isar/Provers: Simplifier and Classical methods now support all kind
  4887 of modifiers used in the past, including 'cong', 'iff', etc.
  4888 
  4889 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4890 of Simplifier and Classical reasoner);
  4891 
  4892 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4893 now support named cases; major packages (inductive, datatype, primrec,
  4894 recdef) support case names and properly name parameters;
  4895 
  4896 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4897 monotonicity conditions are extracted to be proven at end of
  4898 calculations;
  4899 
  4900 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4901 method anyway;
  4902 
  4903 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4904 split_if split_if_asm; datatype package provides theorems foo.splits =
  4905 foo.split foo.split_asm for each datatype;
  4906 
  4907 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4908 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4909 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4910 use "(cases (simplified))" method in proper proof texts);
  4911 
  4912 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4913 
  4914 * Isar: names of theorems etc. may be natural numbers as well;
  4915 
  4916 * Isar: 'pr' command: optional arguments for goals_limit and
  4917 ProofContext.prems_limit; no longer prints theory contexts, but only
  4918 proof states;
  4919 
  4920 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4921 additional print modes to be specified; e.g. "pr(latex)" will print
  4922 proof state according to the Isabelle LaTeX style;
  4923 
  4924 * Isar: improved support for emulating tactic scripts, including proof
  4925 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4926 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4927 (for HOL datatypes);
  4928 
  4929 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4930 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4931 'proof method scripts' have to be in depth-first order;
  4932 
  4933 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4934 
  4935 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4936 should instead use individual commands for printing items
  4937 (print_commands, print_methods etc.);
  4938 
  4939 * Isar: added 'nothing' --- the empty list of theorems;
  4940 
  4941 
  4942 *** HOL ***
  4943 
  4944 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4945 corresponding virtual machine and a specification of its bytecode
  4946 verifier and a lightweight bytecode verifier, including proofs of
  4947 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4948 Cornelia Pusch (see also the homepage of project Bali at
  4949 http://isabelle.in.tum.de/Bali/);
  4950 
  4951 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4952 Clemens Ballarin;
  4953 
  4954 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4955 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4956 Rasmussen;
  4957 
  4958 * HOL/Lattice: fundamental concepts of lattice theory and order
  4959 structures, including duals, properties of bounds versus algebraic
  4960 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4961 Theorem for complete lattices etc.; may also serve as a demonstration
  4962 for abstract algebraic reasoning using axiomatic type classes, and
  4963 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4964 
  4965 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4966 von Oheimb;
  4967 
  4968 * HOL/IMPP: extension of IMP with local variables and mutually
  4969 recursive procedures, by David von Oheimb;
  4970 
  4971 * HOL/Lambda: converted into new-style theory and document;
  4972 
  4973 * HOL/ex/Multiquote: example of multiple nested quotations and
  4974 anti-quotations -- basically a generalized version of de-Bruijn
  4975 representation; very useful in avoiding lifting of operations;
  4976 
  4977 * HOL/record: added general record equality rule to simpset; fixed
  4978 select-update simplification procedure to handle extended records as
  4979 well; admit "r" as field name;
  4980 
  4981 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4982 other numeric types and also as the identity of groups, rings, etc.;
  4983 
  4984 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4985 Types nat and int belong to this axclass;
  4986 
  4987 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4988    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4989    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4990   two terms #m*u and #n*u are replaced by #(m+n)*u
  4991     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4992   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4993     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4994 
  4995 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4996 powerful prover for predicate logic but knows nothing of clasets; see
  4997 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4998 
  4999 * HOL: new version of "case_tac" subsumes both boolean case split and
  5000 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  5001 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  5002 
  5003 * HOL: simplification no longer dives into case-expressions: only the
  5004 selector expression is simplified, but not the remaining arms; to
  5005 enable full simplification of case-expressions for datatype t, you may
  5006 remove t.weak_case_cong from the simpset, either globally (Delcongs
  5007 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  5008 
  5009 * HOL/recdef: the recursion equations generated by 'recdef' for
  5010 function 'f' are now called f.simps instead of f.rules; if all
  5011 termination conditions are proved automatically, these simplification
  5012 rules are added to the simpset, as in primrec; rules may be named
  5013 individually as well, resulting in a separate list of theorems for
  5014 each equation;
  5015 
  5016 * HOL/While is a new theory that provides a while-combinator. It
  5017 permits the definition of tail-recursive functions without the
  5018 provision of a termination measure. The latter is necessary once the
  5019 invariant proof rule for while is applied.
  5020 
  5021 * HOL: new (overloaded) notation for the set of elements below/above
  5022 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5023 
  5024 * HOL: theorems impI, allI, ballI bound as "strip";
  5025 
  5026 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5027 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5028 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5029 
  5030 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5031 
  5032 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5033 main HOL, but was unused);
  5034 
  5035 * HOL: fewer consts declared as global (e.g. have to refer to
  5036 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5037 
  5038 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5039 in case of overlap with user translations (e.g. judgements over
  5040 tuples); (note that the underlying logical represenation is still
  5041 bogus);
  5042 
  5043 
  5044 *** ZF ***
  5045 
  5046 * ZF: simplification automatically cancels common terms in arithmetic
  5047 expressions over nat and int;
  5048 
  5049 * ZF: new treatment of nat to minimize type-checking: all operators
  5050 coerce their operands to a natural number using the function natify,
  5051 making the algebraic laws unconditional;
  5052 
  5053 * ZF: as above, for int: operators coerce their operands to an integer
  5054 using the function intify;
  5055 
  5056 * ZF: the integer library now contains many of the usual laws for the
  5057 orderings, including $<=, and monotonicity laws for $+ and $*;
  5058 
  5059 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5060 simplification;
  5061 
  5062 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5063 to the simplifier and classical reasoner simultaneously;
  5064 
  5065 
  5066 *** General ***
  5067 
  5068 * Provers: blast_tac now handles actual object-logic rules as
  5069 assumptions; note that auto_tac uses blast_tac internally as well;
  5070 
  5071 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5072 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5073 
  5074 * Provers: delrules now handles destruct rules as well (no longer need
  5075 explicit make_elim);
  5076 
  5077 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5078   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5079 use instead the strong form,
  5080   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5081 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5082 from destruct-rules;
  5083 
  5084 * Provers: Simplifier.easy_setup provides a fast path to basic
  5085 Simplifier setup for new object-logics;
  5086 
  5087 * Pure: AST translation rules no longer require constant head on LHS;
  5088 
  5089 * Pure: improved name spaces: ambiguous output is qualified; support
  5090 for hiding of names;
  5091 
  5092 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5093 XSYMBOL_HOME; no longer need to do manual configuration in most
  5094 situations;
  5095 
  5096 * system: compression of ML heaps images may now be controlled via -c
  5097 option of isabelle and isatool usedir (currently only observed by
  5098 Poly/ML);
  5099 
  5100 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5101 useful for remote X11);
  5102 
  5103 * system: provide TAGS file for Isabelle sources;
  5104 
  5105 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5106 order;
  5107 
  5108 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5109 timing flag supersedes proof_timing and Toplevel.trace;
  5110 
  5111 * ML: new combinators |>> and |>>> for incremental transformations
  5112 with secondary results (e.g. certain theory extensions):
  5113 
  5114 * ML: PureThy.add_defs gets additional argument to indicate potential
  5115 overloading (usually false);
  5116 
  5117 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5118 results;
  5119 
  5120 
  5121 
  5122 New in Isabelle99 (October 1999)
  5123 --------------------------------
  5124 
  5125 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5126 
  5127 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5128 are no longer simplified.  (This allows the simplifier to unfold recursive
  5129 functional programs.)  To restore the old behaviour, declare
  5130 
  5131     Delcongs [if_weak_cong];
  5132 
  5133 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5134 complement;
  5135 
  5136 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5137 
  5138 * HOL/datatype: mutual_induct_tac no longer exists --
  5139   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5140 
  5141 * HOL/typedef: fixed type inference for representing set; type
  5142 arguments now have to occur explicitly on the rhs as type constraints;
  5143 
  5144 * ZF: The con_defs part of an inductive definition may no longer refer
  5145 to constants declared in the same theory;
  5146 
  5147 * HOL, ZF: the function mk_cases, generated by the inductive
  5148 definition package, has lost an argument.  To simplify its result, it
  5149 uses the default simpset instead of a supplied list of theorems.
  5150 
  5151 * HOL/List: the constructors of type list are now Nil and Cons;
  5152 
  5153 * Simplifier: the type of the infix ML functions
  5154         setSSolver addSSolver setSolver addSolver
  5155 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5156 for packaging solvers. A solver is created via
  5157         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5158 where the string argument is only a comment.
  5159 
  5160 
  5161 *** Proof tools ***
  5162 
  5163 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5164 decision procedure for linear arithmetic. Currently it is used for
  5165 types `nat', `int', and `real' in HOL (see below); it can, should and
  5166 will be instantiated for other types and logics as well.
  5167 
  5168 * The simplifier now accepts rewrite rules with flexible heads, eg
  5169      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5170   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5171   matching.
  5172 
  5173 
  5174 *** General ***
  5175 
  5176 * New Isabelle/Isar subsystem provides an alternative to traditional
  5177 tactical theorem proving; together with the ProofGeneral/isar user
  5178 interface it offers an interactive environment for developing human
  5179 readable proof documents (Isar == Intelligible semi-automated
  5180 reasoning); for further information see isatool doc isar-ref,
  5181 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5182 
  5183 * improved and simplified presentation of theories: better HTML markup
  5184 (including colors), graph views in several sizes; isatool usedir now
  5185 provides a proper interface for user theories (via -P option); actual
  5186 document preparation based on (PDF)LaTeX is available as well (for
  5187 new-style theories only); see isatool doc system for more information;
  5188 
  5189 * native support for Proof General, both for classic Isabelle and
  5190 Isabelle/Isar;
  5191 
  5192 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5193 using the graph browser tool;
  5194 
  5195 * Isabelle manuals now also available as PDF;
  5196 
  5197 * theory loader rewritten from scratch (may not be fully
  5198 bug-compatible); old loadpath variable has been replaced by show_path,
  5199 add_path, del_path, reset_path functions; new operations such as
  5200 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5201 isatool doc ref);
  5202 
  5203 * improved isatool install: option -k creates KDE application icon,
  5204 option -p DIR installs standalone binaries;
  5205 
  5206 * added ML_PLATFORM setting (useful for cross-platform installations);
  5207 more robust handling of platform specific ML images for SML/NJ;
  5208 
  5209 * the settings environment is now statically scoped, i.e. it is never
  5210 created again in sub-processes invoked from isabelle, isatool, or
  5211 Isabelle;
  5212 
  5213 * path element specification '~~' refers to '$ISABELLE_HOME';
  5214 
  5215 * in locales, the "assumes" and "defines" parts may be omitted if
  5216 empty;
  5217 
  5218 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5219 long arrows);
  5220 
  5221 * new print_mode "HTML";
  5222 
  5223 * new flag show_tags controls display of tags of theorems (which are
  5224 basically just comments that may be attached by some tools);
  5225 
  5226 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5227 mode and goal output format:
  5228 
  5229 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5230 244c244
  5231 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5232 ---
  5233 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5234 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5235 181c181
  5236 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5237 ---
  5238 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5239 
  5240 * function bind_thms stores lists of theorems (cf. bind_thm);
  5241 
  5242 * new shorthand tactics ftac, eatac, datac, fatac;
  5243 
  5244 * qed (and friends) now accept "" as result name; in that case the
  5245 theorem is not stored, but proper checks and presentation of the
  5246 result still apply;
  5247 
  5248 * theorem database now also indexes constants "Trueprop", "all",
  5249 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5250 
  5251 
  5252 *** HOL ***
  5253 
  5254 ** HOL arithmetic **
  5255 
  5256 * There are now decision procedures for linear arithmetic over nat and
  5257 int:
  5258 
  5259 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5260 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5261 are treated as atomic; subformulae not involving type `nat' or `int'
  5262 are ignored; quantified subformulae are ignored unless they are
  5263 positive universal or negative existential. The tactic has to be
  5264 invoked by hand and can be a little bit slow. In particular, the
  5265 running time is exponential in the number of occurrences of `min' and
  5266 `max', and `-' on `nat'.
  5267 
  5268 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5269 (negated) (in)equalities among the premises and the conclusion into
  5270 account (i.e. no compound formulae) and does not know about `min' and
  5271 `max', and `-' on `nat'. It is fast and is used automatically by the
  5272 simplifier.
  5273 
  5274 NB: At the moment, these decision procedures do not cope with mixed
  5275 nat/int formulae where the two parts interact, such as `m < n ==>
  5276 int(m) < int(n)'.
  5277 
  5278 * HOL/Numeral provides a generic theory of numerals (encoded
  5279 efficiently as bit strings); setup for types nat/int/real is in place;
  5280 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5281 int, existing theories and proof scripts may require a few additional
  5282 type constraints;
  5283 
  5284 * integer division and remainder can now be performed on constant
  5285 arguments;
  5286 
  5287 * many properties of integer multiplication, division and remainder
  5288 are now available;
  5289 
  5290 * An interface to the Stanford Validity Checker (SVC) is available through the
  5291 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5292 are proved automatically.  SVC must be installed separately, and its results
  5293 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5294 invocation of the underlying oracle).  For SVC see
  5295   http://verify.stanford.edu/SVC
  5296 
  5297 * IsaMakefile: the HOL-Real target now builds an actual image;
  5298 
  5299 
  5300 ** HOL misc **
  5301 
  5302 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5303 (in Isabelle/Isar) -- by Gertrud Bauer;
  5304 
  5305 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5306 analysis for assembly languages with subtypes;
  5307 
  5308 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5309 -- avoids syntactic ambiguities and treats state, transition, and
  5310 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5311 changed syntax and (many) tactics;
  5312 
  5313 * HOL/inductive: Now also handles more general introduction rules such
  5314   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5315   theorems are now maintained within the theory (maintained via the
  5316   "mono" attribute);
  5317 
  5318 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5319   (using function types) such as
  5320 
  5321   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5322 
  5323 * HOL/record: record_simproc (part of the default simpset) takes care
  5324 of selectors applied to updated records; record_split_tac is no longer
  5325 part of the default claset; update_defs may now be removed from the
  5326 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5327 
  5328   claset_ref () := claset() addSWrapper record_split_wrapper;
  5329   Delsimprocs [record_simproc]
  5330 
  5331 * HOL/typedef: fixed type inference for representing set; type
  5332 arguments now have to occur explicitly on the rhs as type constraints;
  5333 
  5334 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5335 names rather than an ML expression;
  5336 
  5337 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5338 supplied later.  Program schemes can be defined, such as
  5339     "While B C s = (if B s then While B C (C s) else s)"
  5340 where the well-founded relation can be chosen after B and C have been given.
  5341 
  5342 * HOL/List: the constructors of type list are now Nil and Cons;
  5343 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5344 course, ML tools referring to List.list.op # etc. have to be adapted;
  5345 
  5346 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5347 disabled by default; run isabelle with option -m HOL to get back to
  5348 the original Gordon/HOL-style output;
  5349 
  5350 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5351 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5352 
  5353 * HOL basic syntax simplified (more orthogonal): all variants of
  5354 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5355 Eps operator is provided as well: "SOME x. P[x]";
  5356 
  5357 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5358 
  5359 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5360 thus available for user theories;
  5361 
  5362 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5363 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5364 time;
  5365 
  5366 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5367 several times and then mp;
  5368 
  5369 
  5370 *** LK ***
  5371 
  5372 * the notation <<...>> is now available as a notation for sequences of
  5373 formulas;
  5374 
  5375 * the simplifier is now installed
  5376 
  5377 * the axiom system has been generalized (thanks to Soren Heilmann)
  5378 
  5379 * the classical reasoner now has a default rule database
  5380 
  5381 
  5382 *** ZF ***
  5383 
  5384 * new primrec section allows primitive recursive functions to be given
  5385 directly (as in HOL) over datatypes and the natural numbers;
  5386 
  5387 * new tactics induct_tac and exhaust_tac for induction (or case
  5388 analysis) over datatypes and the natural numbers;
  5389 
  5390 * the datatype declaration of type T now defines the recursor T_rec;
  5391 
  5392 * simplification automatically does freeness reasoning for datatype
  5393 constructors;
  5394 
  5395 * automatic type-inference, with AddTCs command to insert new
  5396 type-checking rules;
  5397 
  5398 * datatype introduction rules are now added as Safe Introduction rules
  5399 to the claset;
  5400 
  5401 * the syntax "if P then x else y" is now available in addition to
  5402 if(P,x,y);
  5403 
  5404 
  5405 *** Internal programming interfaces ***
  5406 
  5407 * tuned simplifier trace output; new flag debug_simp;
  5408 
  5409 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5410 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5411 
  5412 * AxClass.axclass_tac lost the theory argument;
  5413 
  5414 * tuned current_goals_markers semantics: begin / end goal avoids
  5415 printing empty lines;
  5416 
  5417 * removed prs and prs_fn hook, which was broken because it did not
  5418 include \n in its semantics, forcing writeln to add one
  5419 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5420 string -> unit if you really want to output text without newline;
  5421 
  5422 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5423 plain output, interface builders may have to enable 'isabelle_font'
  5424 mode to get Isabelle font glyphs as before;
  5425 
  5426 * refined token_translation interface; INCOMPATIBILITY: output length
  5427 now of type real instead of int;
  5428 
  5429 * theory loader actions may be traced via new ThyInfo.add_hook
  5430 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5431 your own database of information attached to *whole* theories -- as
  5432 opposed to intra-theory data slots offered via TheoryDataFun;
  5433 
  5434 * proper handling of dangling sort hypotheses (at last!);
  5435 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5436 extra sort hypotheses that can be witnessed from the type signature;
  5437 the force_strip_shyps flag is gone, any remaining shyps are simply
  5438 left in the theorem (with a warning issued by strip_shyps_warning);
  5439 
  5440 
  5441 
  5442 New in Isabelle98-1 (October 1998)
  5443 ----------------------------------
  5444 
  5445 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5446 
  5447 * several changes of automated proof tools;
  5448 
  5449 * HOL: major changes to the inductive and datatype packages, including
  5450 some minor incompatibilities of theory syntax;
  5451 
  5452 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5453 called `inj_on';
  5454 
  5455 * HOL: removed duplicate thms in Arith:
  5456   less_imp_add_less  should be replaced by  trans_less_add1
  5457   le_imp_add_le      should be replaced by  trans_le_add1
  5458 
  5459 * HOL: unary minus is now overloaded (new type constraints may be
  5460 required);
  5461 
  5462 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5463 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5464 now taken as an integer constant.
  5465 
  5466 * Pure: ML function 'theory_of' renamed to 'theory';
  5467 
  5468 
  5469 *** Proof tools ***
  5470 
  5471 * Simplifier:
  5472   1. Asm_full_simp_tac is now more aggressive.
  5473      1. It will sometimes reorient premises if that increases their power to
  5474         simplify.
  5475      2. It does no longer proceed strictly from left to right but may also
  5476         rotate premises to achieve further simplification.
  5477      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5478      old Asm_full_simp_tac in that it does not rotate premises.
  5479   2. The simplifier now knows a little bit about nat-arithmetic.
  5480 
  5481 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5482 allows for selected deletion of wrappers, by introduction of names for
  5483 wrapper functionals.  This implies that addbefore, addSbefore,
  5484 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5485 and that adding two tactics with the same name overwrites the first
  5486 one (emitting a warning).
  5487   type wrapper = (int -> tactic) -> (int -> tactic)
  5488   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5489   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5490   delWrapper, delSWrapper: claset *  string            -> claset
  5491   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5492 
  5493 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5494 semantics; addbefore now affects only the unsafe part of step_tac
  5495 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5496 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5497 by Force_tac;
  5498 
  5499 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5500 compWrapper; added safe wrapper (and access functions for it);
  5501 
  5502 * HOL/split_all_tac is now much faster and fails if there is nothing
  5503 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5504 and the names of the automatically generated variables have changed.
  5505 split_all_tac has moved within claset() from unsafe wrappers to safe
  5506 wrappers, which means that !!-bound variables are split much more
  5507 aggressively, and safe_tac and clarify_tac now split such variables.
  5508 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5509 Note: the same holds for record_split_tac, which does the job of
  5510 split_all_tac for record fields.
  5511 
  5512 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5513 permanently to the default simpset using Addsplits just like
  5514 Addsimps. They can be removed via Delsplits just like
  5515 Delsimps. Lower-case versions are also available.
  5516 
  5517 * HOL/Simplifier: The rule split_if is now part of the default
  5518 simpset. This means that the simplifier will eliminate all occurrences
  5519 of if-then-else in the conclusion of a goal. To prevent this, you can
  5520 either remove split_if completely from the default simpset by
  5521 `Delsplits [split_if]' or remove it in a specific call of the
  5522 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5523 other case splitting rules to/from the default simpset: every datatype
  5524 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5525 t is the name of the datatype).
  5526 
  5527 * Classical reasoner / Simplifier combination: new force_tac (and
  5528 derivatives Force_tac, force) combines rewriting and classical
  5529 reasoning (and whatever other tools) similarly to auto_tac, but is
  5530 aimed to solve the given subgoal completely.
  5531 
  5532 
  5533 *** General ***
  5534 
  5535 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5536 and `goalw': the theory is no longer needed as an explicit argument -
  5537 the current theory context is used; assumptions are no longer returned
  5538 at the ML-level unless one of them starts with ==> or !!; it is
  5539 recommended to convert to these new commands using isatool fixgoal
  5540 (backup your sources first!);
  5541 
  5542 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5543 the current theory context, and 'theory' to lookup stored theories;
  5544 
  5545 * new theory section 'locale' for declaring constants, assumptions and
  5546 definitions that have local scope;
  5547 
  5548 * new theory section 'nonterminals' for purely syntactic types;
  5549 
  5550 * new theory section 'setup' for generic ML setup functions
  5551 (e.g. package initialization);
  5552 
  5553 * the distribution now includes Isabelle icons: see
  5554 lib/logo/isabelle-{small,tiny}.xpm;
  5555 
  5556 * isatool install - install binaries with absolute references to
  5557 ISABELLE_HOME/bin;
  5558 
  5559 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5560 
  5561 * print mode 'emacs' reserved for Isamode;
  5562 
  5563 * support multiple print (ast) translations per constant name;
  5564 
  5565 * theorems involving oracles are now printed with a suffixed [!];
  5566 
  5567 
  5568 *** HOL ***
  5569 
  5570 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5571 
  5572 * HOL/inductive package reorganized and improved: now supports mutual
  5573 definitions such as
  5574 
  5575   inductive EVEN ODD
  5576     intrs
  5577       null "0 : EVEN"
  5578       oddI "n : EVEN ==> Suc n : ODD"
  5579       evenI "n : ODD ==> Suc n : EVEN"
  5580 
  5581 new theorem list "elims" contains an elimination rule for each of the
  5582 recursive sets; inductive definitions now handle disjunctive premises
  5583 correctly (also ZF);
  5584 
  5585 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5586 "mutual_induct" no longer exists - the induction rule is always
  5587 contained in "induct";
  5588 
  5589 
  5590 * HOL/datatype package re-implemented and greatly improved: now
  5591 supports mutually recursive datatypes such as
  5592 
  5593   datatype
  5594     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5595             | SUM ('a aexp) ('a aexp)
  5596             | DIFF ('a aexp) ('a aexp)
  5597             | NUM 'a
  5598   and
  5599     'a bexp = LESS ('a aexp) ('a aexp)
  5600             | AND ('a bexp) ('a bexp)
  5601             | OR ('a bexp) ('a bexp)
  5602 
  5603 as well as indirectly recursive datatypes such as
  5604 
  5605   datatype
  5606     ('a, 'b) term = Var 'a
  5607                   | App 'b ((('a, 'b) term) list)
  5608 
  5609 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5610 induction on mutually / indirectly recursive datatypes.
  5611 
  5612 Primrec equations are now stored in theory and can be accessed via
  5613 <function_name>.simps.
  5614 
  5615 INCOMPATIBILITIES:
  5616 
  5617   - Theories using datatypes must now have theory Datatype as an
  5618     ancestor.
  5619   - The specific <typename>.induct_tac no longer exists - use the
  5620     generic induct_tac instead.
  5621   - natE has been renamed to nat.exhaust - use exhaust_tac
  5622     instead of res_inst_tac ... natE. Note that the variable
  5623     names in nat.exhaust differ from the names in natE, this
  5624     may cause some "fragile" proofs to fail.
  5625   - The theorems split_<typename>_case and split_<typename>_case_asm
  5626     have been renamed to <typename>.split and <typename>.split_asm.
  5627   - Since default sorts of type variables are now handled correctly,
  5628     some datatype definitions may have to be annotated with explicit
  5629     sort constraints.
  5630   - Primrec definitions no longer require function name and type
  5631     of recursive argument.
  5632 
  5633 Consider using isatool fixdatatype to adapt your theories and proof
  5634 scripts to the new package (backup your sources first!).
  5635 
  5636 
  5637 * HOL/record package: considerably improved implementation; now
  5638 includes concrete syntax for record types, terms, updates; theorems
  5639 for surjective pairing and splitting !!-bound record variables; proof
  5640 support is as follows:
  5641 
  5642   1) standard conversions (selectors or updates applied to record
  5643 constructor terms) are part of the standard simpset;
  5644 
  5645   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5646 made part of standard simpset and claset via addIffs;
  5647 
  5648   3) a tactic for record field splitting (record_split_tac) is part of
  5649 the standard claset (addSWrapper);
  5650 
  5651 To get a better idea about these rules you may retrieve them via
  5652 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5653 the name of your record type.
  5654 
  5655 The split tactic 3) conceptually simplifies by the following rule:
  5656 
  5657   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5658 
  5659 Thus any record variable that is bound by meta-all will automatically
  5660 blow up into some record constructor term, consequently the
  5661 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5662 solve record problems automatically.
  5663 
  5664 
  5665 * reorganized the main HOL image: HOL/Integ and String loaded by
  5666 default; theory Main includes everything;
  5667 
  5668 * automatic simplification of integer sums and comparisons, using cancellation;
  5669 
  5670 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5671 
  5672 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5673 
  5674 * many new identities for unions, intersections, set difference, etc.;
  5675 
  5676 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5677 called split_if, split_split, split_sum_case and split_nat_case (to go
  5678 with add/delsplits);
  5679 
  5680 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5681 (?x::unit) = (); this is made part of the default simpset, which COULD
  5682 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5683 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5684 unit_abs_eta_conv is added in order to counter the effect of
  5685 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5686 %u.f();
  5687 
  5688 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5689 makes more sense);
  5690 
  5691 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5692   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5693   disjointness reasoning but breaking a few old proofs.
  5694 
  5695 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5696 to 'converse' from 'inverse' (for compatibility with ZF and some
  5697 literature);
  5698 
  5699 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5700 the well-founded relation;
  5701 
  5702 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5703     Compl A.  The "Compl" syntax remains available as input syntax for this
  5704     release ONLY.
  5705 
  5706 * HOL/Update: new theory of function updates:
  5707     f(a:=b) == %x. if x=a then b else f x
  5708 may also be iterated as in f(a:=b,c:=d,...);
  5709 
  5710 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5711 
  5712 * HOL/List:
  5713   - new function list_update written xs[i:=v] that updates the i-th
  5714     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5715   - new function `upt' written [i..j(] which generates the list
  5716     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5717     bound write [i..j], which is a shorthand for [i..j+1(].
  5718   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5719 
  5720 * HOL/Arith:
  5721   - removed 'pred' (predecessor) function;
  5722   - generalized some theorems about n-1;
  5723   - many new laws about "div" and "mod";
  5724   - new laws about greatest common divisors (see theory ex/Primes);
  5725 
  5726 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5727 instead of "inverse";
  5728 
  5729 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5730   of the multiset ordering;
  5731 
  5732 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5733   (not included by default);
  5734 
  5735 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5736 
  5737 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5738   programs, i.e. different program variables may have different types.
  5739 
  5740 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5741   [previously, this check worked only if the rewrite rule was unconditional]
  5742   Now rew can involve either definitions or equalities (either == or =).
  5743 
  5744 
  5745 *** ZF ***
  5746 
  5747 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5748   only the theorems proved on ZF.ML;
  5749 
  5750 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5751   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5752   disjointness reasoning but breaking a few old proofs.
  5753 
  5754 * ZF/Update: new theory of function updates
  5755     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5756   may also be iterated as in f(a:=b,c:=d,...);
  5757 
  5758 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5759 
  5760 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5761   [previously, this check worked only if the rewrite rule was unconditional]
  5762   Now rew can involve either definitions or equalities (either == or =).
  5763 
  5764 * case_tac provided for compatibility with HOL
  5765     (like the old excluded_middle_tac, but with subgoals swapped)
  5766 
  5767 
  5768 *** Internal programming interfaces ***
  5769 
  5770 * Pure: several new basic modules made available for general use, see
  5771 also src/Pure/README;
  5772 
  5773 * improved the theory data mechanism to support encapsulation (data
  5774 kind name replaced by private Object.kind, acting as authorization
  5775 key); new type-safe user interface via functor TheoryDataFun; generic
  5776 print_data function becomes basically useless;
  5777 
  5778 * removed global_names compatibility flag -- all theory declarations
  5779 are qualified by default;
  5780 
  5781 * module Pure/Syntax now offers quote / antiquote translation
  5782 functions (useful for Hoare logic etc. with implicit dependencies);
  5783 see HOL/ex/Antiquote for an example use;
  5784 
  5785 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5786 cterm -> thm;
  5787 
  5788 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5789 subgoal;
  5790 
  5791 * Display.print_goals function moved to Locale.print_goals;
  5792 
  5793 * standard print function for goals supports current_goals_markers
  5794 variable for marking begin of proof, end of proof, start of goal; the
  5795 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5796 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5797 for example;
  5798 
  5799 
  5800 
  5801 New in Isabelle98 (January 1998)
  5802 --------------------------------
  5803 
  5804 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5805 
  5806 * changed lexical syntax of terms / types: dots made part of long
  5807 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5808 
  5809 * simpset (and claset) reference variable replaced by functions
  5810 simpset / simpset_ref;
  5811 
  5812 * no longer supports theory aliases (via merge) and non-trivial
  5813 implicit merge of thms' signatures;
  5814 
  5815 * most internal names of constants changed due to qualified names;
  5816 
  5817 * changed Pure/Sequence interface (see Pure/seq.ML);
  5818 
  5819 
  5820 *** General Changes ***
  5821 
  5822 * hierachically structured name spaces (for consts, types, axms, thms
  5823 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5824 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5825 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5826 long_names for fully qualified output names; NOTE: ML programs
  5827 (special tactics, packages etc.) referring to internal names may have
  5828 to be adapted to cope with fully qualified names; in case of severe
  5829 backward campatibility problems try setting 'global_names' at compile
  5830 time to have enrything declared within a flat name space; one may also
  5831 fine tune name declarations in theories via the 'global' and 'local'
  5832 section;
  5833 
  5834 * reimplemented the implicit simpset and claset using the new anytype
  5835 data filed in signatures; references simpset:simpset ref etc. are
  5836 replaced by functions simpset:unit->simpset and
  5837 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5838 to patch your ML files accordingly;
  5839 
  5840 * HTML output now includes theory graph data for display with Java
  5841 applet or isatool browser; data generated automatically via isatool
  5842 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5843 
  5844 * defs may now be conditional; improved rewrite_goals_tac to handle
  5845 conditional equations;
  5846 
  5847 * defs now admits additional type arguments, using TYPE('a) syntax;
  5848 
  5849 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5850 creates a new theory node; implicit merge of thms' signatures is
  5851 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5852 transfer:theory->thm->thm in (rare) cases;
  5853 
  5854 * improved handling of draft signatures / theories; draft thms (and
  5855 ctyps, cterms) are automatically promoted to real ones;
  5856 
  5857 * slightly changed interfaces for oracles: admit many per theory, named
  5858 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5859 
  5860 * print_goals: optional output of const types (set show_consts and
  5861 show_types);
  5862 
  5863 * improved output of warnings (###) and errors (***);
  5864 
  5865 * subgoal_tac displays a warning if the new subgoal has type variables;
  5866 
  5867 * removed old README and Makefiles;
  5868 
  5869 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5870 
  5871 * removed obsolete init_pps and init_database;
  5872 
  5873 * deleted the obsolete tactical STATE, which was declared by
  5874     fun STATE tacfun st = tacfun st st;
  5875 
  5876 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5877 (which abbreviates $HOME);
  5878 
  5879 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5880 use isatool fixseq to adapt your ML programs (this works for fully
  5881 qualified references to the Sequence structure only!);
  5882 
  5883 * use_thy no longer requires writable current directory; it always
  5884 reloads .ML *and* .thy file, if either one is out of date;
  5885 
  5886 
  5887 *** Classical Reasoner ***
  5888 
  5889 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5890 tactics that use classical reasoning to simplify a subgoal without
  5891 splitting it into several subgoals;
  5892 
  5893 * Safe_tac: like safe_tac but uses the default claset;
  5894 
  5895 
  5896 *** Simplifier ***
  5897 
  5898 * added simplification meta rules:
  5899     (asm_)(full_)simplify: simpset -> thm -> thm;
  5900 
  5901 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5902 logics (again);
  5903 
  5904 * added prems argument to simplification procedures;
  5905 
  5906 * HOL, FOL, ZF: added infix function `addsplits':
  5907   instead of `<simpset> setloop (split_tac <thms>)'
  5908   you can simply write `<simpset> addsplits <thms>'
  5909 
  5910 
  5911 *** Syntax ***
  5912 
  5913 * TYPE('a) syntax for type reflection terms;
  5914 
  5915 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5916 
  5917 * pretty printer: changed order of mixfix annotation preference (again!);
  5918 
  5919 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5920 
  5921 
  5922 *** HOL ***
  5923 
  5924 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5925   with `addloop' of the simplifier to faciliate case splitting in premises.
  5926 
  5927 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5928 
  5929 * HOL/Auth: new protocol proofs including some for the Internet
  5930   protocol TLS;
  5931 
  5932 * HOL/Map: new theory of `maps' a la VDM;
  5933 
  5934 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5935 cancelling out common nat summands from =, <, <= (in)equalities, or
  5936 differences; simplification procedures nat_cancel_factor for
  5937 cancelling common factor from =, <, <= (in)equalities over natural
  5938 sums; nat_cancel contains both kinds of procedures, it is installed by
  5939 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5940 
  5941 * HOL/simplifier: terms of the form
  5942   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5943   are rewritten to
  5944   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5945   and those of the form
  5946   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5947   are rewritten to
  5948   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5949 
  5950 * HOL/datatype
  5951   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5952 
  5953   P(t_case f1 ... fn x) =
  5954      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5955         ...
  5956        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5957      )
  5958 
  5959   and a theorem `split_t_case_asm' of the form
  5960 
  5961   P(t_case f1 ... fn x) =
  5962     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5963         ...
  5964        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5965      )
  5966   which can be added to a simpset via `addsplits'. The existing theorems
  5967   expand_list_case and expand_option_case have been renamed to
  5968   split_list_case and split_option_case.
  5969 
  5970 * HOL/Arithmetic:
  5971   - `pred n' is automatically converted to `n-1'.
  5972     Users are strongly encouraged not to use `pred' any longer,
  5973     because it will disappear altogether at some point.
  5974   - Users are strongly encouraged to write "0 < n" rather than
  5975     "n ~= 0". Theorems and proof tools have been modified towards this
  5976     `standard'.
  5977 
  5978 * HOL/Lists:
  5979   the function "set_of_list" has been renamed "set" (and its theorems too);
  5980   the function "nth" now takes its arguments in the reverse order and
  5981   has acquired the infix notation "!" as in "xs!n".
  5982 
  5983 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5984 
  5985 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5986   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5987 
  5988 * HOL/record: extensible records with schematic structural subtyping
  5989 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5990 still lacks various theorems and concrete record syntax;
  5991 
  5992 
  5993 *** HOLCF ***
  5994 
  5995 * removed "axioms" and "generated by" sections;
  5996 
  5997 * replaced "ops" section by extended "consts" section, which is capable of
  5998   handling the continuous function space "->" directly;
  5999 
  6000 * domain package:
  6001   . proves theorems immediately and stores them in the theory,
  6002   . creates hierachical name space,
  6003   . now uses normal mixfix annotations (instead of cinfix...),
  6004   . minor changes to some names and values (for consistency),
  6005   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  6006   . separator between mutual domain defs: changed "," to "and",
  6007   . improved handling of sort constraints;  now they have to
  6008     appear on the left-hand side of the equations only;
  6009 
  6010 * fixed LAM <x,y,zs>.b syntax;
  6011 
  6012 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  6013 adm (%x. P (t x)), where P is chainfinite and t continuous;
  6014 
  6015 
  6016 *** FOL and ZF ***
  6017 
  6018 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6019   with `addloop' of the simplifier to faciliate case splitting in premises.
  6020 
  6021 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6022 in HOL, they strip ALL and --> from proved theorems;
  6023 
  6024 
  6025 
  6026 New in Isabelle94-8 (May 1997)
  6027 ------------------------------
  6028 
  6029 *** General Changes ***
  6030 
  6031 * new utilities to build / run / maintain Isabelle etc. (in parts
  6032 still somewhat experimental); old Makefiles etc. still functional;
  6033 
  6034 * new 'Isabelle System Manual';
  6035 
  6036 * INSTALL text, together with ./configure and ./build scripts;
  6037 
  6038 * reimplemented type inference for greater efficiency, better error
  6039 messages and clean internal interface;
  6040 
  6041 * prlim command for dealing with lots of subgoals (an easier way of
  6042 setting goals_limit);
  6043 
  6044 
  6045 *** Syntax ***
  6046 
  6047 * supports alternative (named) syntax tables (parser and pretty
  6048 printer); internal interface is provided by add_modesyntax(_i);
  6049 
  6050 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6051 be used in conjunction with the Isabelle symbol font; uses the
  6052 "symbols" syntax table;
  6053 
  6054 * added token_translation interface (may translate name tokens in
  6055 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6056 the current print_mode); IMPORTANT: user print translation functions
  6057 are responsible for marking newly introduced bounds
  6058 (Syntax.mark_boundT);
  6059 
  6060 * token translations for modes "xterm" and "xterm_color" that display
  6061 names in bold, underline etc. or colors (which requires a color
  6062 version of xterm);
  6063 
  6064 * infixes may now be declared with names independent of their syntax;
  6065 
  6066 * added typed_print_translation (like print_translation, but may
  6067 access type of constant);
  6068 
  6069 
  6070 *** Classical Reasoner ***
  6071 
  6072 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6073 some limitations.  Blast_tac...
  6074   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6075   + ignores elimination rules that don't have the correct format
  6076         (the conclusion MUST be a formula variable)
  6077   + ignores types, which can make HOL proofs fail
  6078   + rules must not require higher-order unification, e.g. apply_type in ZF
  6079     [message "Function Var's argument not a bound variable" relates to this]
  6080   + its proof strategy is more general but can actually be slower
  6081 
  6082 * substitution with equality assumptions no longer permutes other
  6083 assumptions;
  6084 
  6085 * minor changes in semantics of addafter (now called addaltern); renamed
  6086 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6087 (and access functions for it);
  6088 
  6089 * improved combination of classical reasoner and simplifier:
  6090   + functions for handling clasimpsets
  6091   + improvement of addss: now the simplifier is called _after_ the
  6092     safe steps.
  6093   + safe variant of addss called addSss: uses safe simplifications
  6094     _during_ the safe steps. It is more complete as it allows multiple
  6095     instantiations of unknowns (e.g. with slow_tac).
  6096 
  6097 *** Simplifier ***
  6098 
  6099 * added interface for simplification procedures (functions that
  6100 produce *proven* rewrite rules on the fly, depending on current
  6101 redex);
  6102 
  6103 * ordering on terms as parameter (used for ordered rewriting);
  6104 
  6105 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6106 
  6107 * the solver is now split into a safe and an unsafe part.
  6108 This should be invisible for the normal user, except that the
  6109 functions setsolver and addsolver have been renamed to setSolver and
  6110 addSolver; added safe_asm_full_simp_tac;
  6111 
  6112 
  6113 *** HOL ***
  6114 
  6115 * a generic induction tactic `induct_tac' which works for all datatypes and
  6116 also for type `nat';
  6117 
  6118 * a generic case distinction tactic `exhaust_tac' which works for all
  6119 datatypes and also for type `nat';
  6120 
  6121 * each datatype comes with a function `size';
  6122 
  6123 * patterns in case expressions allow tuple patterns as arguments to
  6124 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6125 
  6126 * primrec now also works with type nat;
  6127 
  6128 * recdef: a new declaration form, allows general recursive functions to be
  6129 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6130 
  6131 * the constant for negation has been renamed from "not" to "Not" to
  6132 harmonize with FOL, ZF, LK, etc.;
  6133 
  6134 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6135 infinite lists;
  6136 
  6137 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6138 
  6139 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6140 problems in commutative rings, using axiomatic type classes for + and *;
  6141 
  6142 * more examples in HOL/MiniML and HOL/Auth;
  6143 
  6144 * more default rewrite rules for quantifiers, union/intersection;
  6145 
  6146 * a new constant `arbitrary == @x.False';
  6147 
  6148 * HOLCF/IOA replaces old HOL/IOA;
  6149 
  6150 * HOLCF changes: derived all rules and arities
  6151   + axiomatic type classes instead of classes
  6152   + typedef instead of faking type definitions
  6153   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6154   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6155   + eliminated the types void, one, tr
  6156   + use unit lift and bool lift (with translations) instead of one and tr
  6157   + eliminated blift from Lift3.thy (use Def instead of blift)
  6158   all eliminated rules are derived as theorems --> no visible changes ;
  6159 
  6160 
  6161 *** ZF ***
  6162 
  6163 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6164 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6165 as ZF_cs addSIs [equalityI];
  6166 
  6167 
  6168 
  6169 New in Isabelle94-7 (November 96)
  6170 ---------------------------------
  6171 
  6172 * allowing negative levels (as offsets) in prlev and choplev;
  6173 
  6174 * super-linear speedup for large simplifications;
  6175 
  6176 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6177 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6178 FAIL); can suppress it using the command Delsimps (ex_simps @
  6179 all_simps); De Morgan laws are also now included, by default;
  6180 
  6181 * improved printing of ==>  :  ~:
  6182 
  6183 * new object-logic "Sequents" adds linear logic, while replacing LK
  6184 and Modal (thanks to Sara Kalvala);
  6185 
  6186 * HOL/Auth: correctness proofs for authentication protocols;
  6187 
  6188 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6189 examples on HOL/Auth);
  6190 
  6191 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6192 the rewriter and classical reasoner simultaneously;
  6193 
  6194 * function uresult no longer returns theorems in "standard" format;
  6195 regain previous version by: val uresult = standard o uresult;
  6196 
  6197 
  6198 
  6199 New in Isabelle94-6
  6200 -------------------
  6201 
  6202 * oracles -- these establish an interface between Isabelle and trusted
  6203 external reasoners, which may deliver results as theorems;
  6204 
  6205 * proof objects (in particular record all uses of oracles);
  6206 
  6207 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6208 
  6209 * "constdefs" section in theory files;
  6210 
  6211 * "primrec" section (HOL) no longer requires names;
  6212 
  6213 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6214 
  6215 
  6216 
  6217 New in Isabelle94-5
  6218 -------------------
  6219 
  6220 * reduced space requirements;
  6221 
  6222 * automatic HTML generation from theories;
  6223 
  6224 * theory files no longer require "..." (quotes) around most types;
  6225 
  6226 * new examples, including two proofs of the Church-Rosser theorem;
  6227 
  6228 * non-curried (1994) version of HOL is no longer distributed;
  6229 
  6230 
  6231 
  6232 New in Isabelle94-4
  6233 -------------------
  6234 
  6235 * greatly reduced space requirements;
  6236 
  6237 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6238 
  6239 * searchable theorem database (see the section "Retrieving theorems" on
  6240 page 8 of the Reference Manual);
  6241 
  6242 * new examples, including Grabczewski's monumental case study of the
  6243 Axiom of Choice;
  6244 
  6245 * The previous version of HOL renamed to Old_HOL;
  6246 
  6247 * The new version of HOL (previously called CHOL) uses a curried syntax
  6248 for functions.  Application looks like f a b instead of f(a,b);
  6249 
  6250 * Mutually recursive inductive definitions finally work in HOL;
  6251 
  6252 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6253 translates to the operator "split";
  6254 
  6255 
  6256 
  6257 New in Isabelle94-3
  6258 -------------------
  6259 
  6260 * new infix operator, addss, allowing the classical reasoner to
  6261 perform simplification at each step of its search.  Example: