NEWS
author haftmann
Mon Apr 20 16:28:13 2009 +0200 (2009-04-20)
changeset 30957 20d01210b9b1
parent 30904 cc6a6047a10f
parent 30955 ef2319d6b6a5
child 30964 e80c06577ade
permissions -rw-r--r--
merged
     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 dedicated constants:
    22 
    23     relpow with infix syntax "^^"
    24     funpow with infix syntax "^o"
    25 
    26 
    27 
    28 New in Isabelle2009 (April 2009)
    29 --------------------------------
    30 
    31 *** General ***
    32 
    33 * Simplified main Isabelle executables, with less surprises on
    34 case-insensitive file-systems (such as Mac OS).
    35 
    36   - The main Isabelle tool wrapper is now called "isabelle" instead of
    37     "isatool."
    38 
    39   - The former "isabelle" alias for "isabelle-process" has been
    40     removed (should rarely occur to regular users).
    41 
    42   - The former "isabelle-interface" and its alias "Isabelle" have been
    43     removed (interfaces are now regular Isabelle tools).
    44 
    45 Within scripts and make files, the Isabelle environment variables
    46 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    47 respectively.  (The latter are still available as legacy feature.)
    48 
    49 The old isabelle-interface wrapper could react in confusing ways if
    50 the interface was uninstalled or changed otherwise.  Individual
    51 interface tool configuration is now more explicit, see also the
    52 Isabelle system manual.  In particular, Proof General is now available
    53 via "isabelle emacs".
    54 
    55 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    56 purge installed copies of Isabelle executables and re-run "isabelle
    57 install -p ...", or use symlinks.
    58 
    59 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    60 old ~/isabelle, which was slightly non-standard and apt to cause
    61 surprises on case-insensitive file-systems (such as Mac OS).
    62 
    63 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    64 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    65 care is required when using older releases of Isabelle.  Note that
    66 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    67 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
    68 
    69 * Proofs of fully specified statements are run in parallel on
    70 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
    71 a regular 4-core machine, if the initial heap space is made reasonably
    72 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
    73 
    74 * The main reference manuals ("isar-ref", "implementation", and
    75 "system") have been updated and extended.  Formally checked references
    76 as hyperlinks are now available uniformly.
    77 
    78 
    79 *** Pure ***
    80 
    81 * Complete re-implementation of locales.  INCOMPATIBILITY in several
    82 respects.  The most important changes are listed below.  See the
    83 Tutorial on Locales ("locales" manual) for details.
    84 
    85 - In locale expressions, instantiation replaces renaming.  Parameters
    86 must be declared in a for clause.  To aid compatibility with previous
    87 parameter inheritance, in locale declarations, parameters that are not
    88 'touched' (instantiation position "_" or omitted) are implicitly added
    89 with their syntax at the beginning of the for clause.
    90 
    91 - Syntax from abbreviations and definitions in locales is available in
    92 locale expressions and context elements.  The latter is particularly
    93 useful in locale declarations.
    94 
    95 - More flexible mechanisms to qualify names generated by locale
    96 expressions.  Qualifiers (prefixes) may be specified in locale
    97 expressions, and can be marked as mandatory (syntax: "name!:") or
    98 optional (syntax "name?:").  The default depends for plain "name:"
    99 depends on the situation where a locale expression is used: in
   100 commands 'locale' and 'sublocale' prefixes are optional, in
   101 'interpretation' and 'interpret' prefixes are mandatory.  The old
   102 implicit qualifiers derived from the parameter names of a locale are
   103 no longer generated.
   104 
   105 - Command "sublocale l < e" replaces "interpretation l < e".  The
   106 instantiation clause in "interpretation" and "interpret" (square
   107 brackets) is no longer available.  Use locale expressions.
   108 
   109 - When converting proof scripts, mandatory qualifiers in
   110 'interpretation' and 'interpret' should be retained by default, even
   111 if this is an INCOMPATIBILITY compared to former behavior.  In the
   112 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   113 in locale expressions range over a single locale instance only.
   114 
   115 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   116 In existing theorem specifications replace the includes element by the
   117 respective context elements of the included locale, omitting those
   118 that are already present in the theorem specification.  Multiple
   119 assume elements of a locale should be replaced by a single one
   120 involving the locale predicate.  In the proof body, declarations (most
   121 notably theorems) may be regained by interpreting the respective
   122 locales in the proof context as required (command "interpret").
   123 
   124 If using "includes" in replacement of a target solely because the
   125 parameter types in the theorem are not as general as in the target,
   126 consider declaring a new locale with additional type constraints on
   127 the parameters (context element "constrains").
   128 
   129 - Discontinued "locale (open)".  INCOMPATIBILITY.
   130 
   131 - Locale interpretation commands no longer attempt to simplify goal.
   132 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   133 methods intro_locales and unfold_locales to clarify.
   134 
   135 - Locale interpretation commands no longer accept interpretation
   136 attributes.  INCOMPATIBILITY.
   137 
   138 * Class declaration: so-called "base sort" must not be given in import
   139 list any longer, but is inferred from the specification.  Particularly
   140 in HOL, write
   141 
   142     class foo = ...
   143 
   144 instead of
   145 
   146     class foo = type + ...
   147 
   148 * Class target: global versions of theorems stemming do not carry a
   149 parameter prefix any longer.  INCOMPATIBILITY.
   150 
   151 * Class 'instance' command no longer accepts attached definitions.
   152 INCOMPATIBILITY, use proper 'instantiation' target instead.
   153 
   154 * Recovered hiding of consts, which was accidentally broken in
   155 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   156 makes c inaccessible; consider using ``hide (open) const c'' instead.
   157 
   158 * Slightly more coherent Pure syntax, with updated documentation in
   159 isar-ref manual.  Removed locales meta_term_syntax and
   160 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   161 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   162 directly in regular applications.
   163 
   164 * There is a new syntactic category "float_const" for signed decimal
   165 fractions (e.g. 123.45 or -123.45).
   166 
   167 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   168 interface with 'setup' command instead.
   169 
   170 * Command 'local_setup' is similar to 'setup', but operates on a local
   171 theory context.
   172 
   173 * The 'axiomatization' command now only works within a global theory
   174 context.  INCOMPATIBILITY.
   175 
   176 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   177 hypotheses.  Sorts required in the course of reasoning need to be
   178 covered by the constraints in the initial statement, completed by the
   179 type instance information of the background theory.  Non-trivial sort
   180 hypotheses, which rarely occur in practice, may be specified via
   181 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   182 
   183   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   184 
   185 The result contains an implicit sort hypotheses as before --
   186 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   187 normalization.
   188 
   189 * Generalized Isar history, with support for linear undo, direct state
   190 addressing etc.
   191 
   192 * Changed defaults for unify configuration options:
   193 
   194   unify_trace_bound = 50 (formerly 25)
   195   unify_search_bound = 60 (formerly 30)
   196 
   197 * Different bookkeeping for code equations (INCOMPATIBILITY):
   198 
   199   a) On theory merge, the last set of code equations for a particular
   200      constant is taken (in accordance with the policy applied by other
   201      parts of the code generator framework).
   202 
   203   b) Code equations stemming from explicit declarations (e.g. code
   204      attribute) gain priority over default code equations stemming
   205      from definition, primrec, fun etc.
   206 
   207 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   208 
   209 * Unified theorem tables for both code code generators.  Thus [code
   210 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   211 
   212 * Command 'find_consts' searches for constants based on type and name
   213 patterns, e.g.
   214 
   215     find_consts "_ => bool"
   216 
   217 By default, matching is against subtypes, but it may be restricted to
   218 the whole type.  Searching by name is possible.  Multiple queries are
   219 conjunctive and queries may be negated by prefixing them with a
   220 hyphen:
   221 
   222     find_consts strict: "_ => bool" name: "Int" -"int => int"
   223 
   224 * New 'find_theorems' criterion "solves" matches theorems that
   225 directly solve the current goal (modulo higher-order unification).
   226 
   227 * Auto solve feature for main theorem statements: whenever a new goal
   228 is stated, "find_theorems solves" is called; any theorems that could
   229 solve the lemma directly are listed as part of the goal state.
   230 Cf. associated options in Proof General Isabelle settings menu,
   231 enabled by default, with reasonable timeout for pathological cases of
   232 higher-order unification.
   233 
   234 
   235 *** Document preparation ***
   236 
   237 * Antiquotation @{lemma} now imitates a regular terminal proof,
   238 demanding keyword 'by' and supporting the full method expression
   239 syntax just like the Isar command 'by'.
   240 
   241 
   242 *** HOL ***
   243 
   244 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   245 points Main and Complex_Main remain as before.
   246 
   247 * Logic image HOL-Plain provides a minimal HOL with the most important
   248 tools available (inductive, datatype, primrec, ...).  This facilitates
   249 experimentation and tool development.  Note that user applications
   250 (and library theories) should never refer to anything below theory
   251 Main, as before.
   252 
   253 * Logic image HOL-Main stops at theory Main, and thus facilitates
   254 experimentation due to shorter build times.
   255 
   256 * Logic image HOL-NSA contains theories of nonstandard analysis which
   257 were previously part of former HOL-Complex.  Entry point Hyperreal
   258 remains valid, but theories formerly using Complex_Main should now use
   259 new entry point Hypercomplex.
   260 
   261 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   262 Posix processes.  Avoids potentially expensive forking of the ML
   263 process.  New thread-based implementation also works on non-Unix
   264 platforms (Cygwin).  Provers are no longer hardwired, but defined
   265 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   266 commands are covered in the isar-ref manual.
   267 
   268 * Wrapper scripts for remote SystemOnTPTP service allows to use
   269 sledgehammer without local ATP installation (Vampire etc.). Other
   270 provers may be included via suitable ML wrappers, see also
   271 src/HOL/ATP_Linkup.thy.
   272 
   273 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   274 menu.
   275 
   276 * The metis method no longer fails because the theorem is too trivial
   277 (contains the empty clause).
   278 
   279 * The metis method now fails in the usual manner, rather than raising
   280 an exception, if it determines that it cannot prove the theorem.
   281 
   282 * Method "coherent" implements a prover for coherent logic (see also
   283 src/Tools/coherent.ML).
   284 
   285 * Constants "undefined" and "default" replace "arbitrary".  Usually
   286 "undefined" is the right choice to replace "arbitrary", though
   287 logically there is no difference.  INCOMPATIBILITY.
   288 
   289 * Command "value" now integrates different evaluation mechanisms.  The
   290 result of the first successful evaluation mechanism is printed.  In
   291 square brackets a particular named evaluation mechanisms may be
   292 specified (currently, [SML], [code] or [nbe]).  See further
   293 src/HOL/ex/Eval_Examples.thy.
   294 
   295 * Normalization by evaluation now allows non-leftlinear equations.
   296 Declare with attribute [code nbe].
   297 
   298 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   299 as the structured Isar versions "cases" and "induct", cf. the
   300 corresponding "cases" and "induct" attributes.  Mutual induction rules
   301 are now presented as a list of individual projections
   302 (e.g. foo_bar.inducts for types foo and bar); the old format with
   303 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   304 rare situations a different rule is selected --- notably nested tuple
   305 elimination instead of former prod.exhaust: use explicit (case_tac t
   306 rule: prod.exhaust) here.
   307 
   308 * Attributes "cases", "induct", "coinduct" support "del" option.
   309 
   310 * Removed fact "case_split_thm", which duplicates "case_split".
   311 
   312 * The option datatype has been moved to a new theory Option.  Renamed
   313 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   314 
   315 * New predicate "strict_mono" classifies strict functions on partial
   316 orders.  With strict functions on linear orders, reasoning about
   317 (in)equalities is facilitated by theorems "strict_mono_eq",
   318 "strict_mono_less_eq" and "strict_mono_less".
   319 
   320 * Some set operations are now proper qualified constants with
   321 authentic syntax.  INCOMPATIBILITY:
   322 
   323     op Int ~>   Set.Int
   324     op Un ~>    Set.Un
   325     INTER ~>    Set.INTER
   326     UNION ~>    Set.UNION
   327     Inter ~>    Set.Inter
   328     Union ~>    Set.Union
   329     {} ~>       Set.empty
   330     UNIV ~>     Set.UNIV
   331 
   332 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   333 theory Set.
   334 
   335 * Auxiliary class "itself" has disappeared -- classes without any
   336 parameter are treated as expected by the 'class' command.
   337 
   338 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   339 
   340 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   341 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   342 
   343 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   344 method "approximation".  It proves formulas on real values by using
   345 interval arithmetic.  In the formulas are also the transcendental
   346 functions sin, cos, tan, atan, ln, exp and the constant pi are
   347 allowed. For examples see
   348 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   349 
   350 * Theory "Reflection" now resides in HOL/Library.
   351 
   352 * Entry point to Word library now simply named "Word".
   353 INCOMPATIBILITY.
   354 
   355 * Made source layout more coherent with logical distribution
   356 structure:
   357 
   358     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   359     src/HOL/Library/Code_Message.thy ~> src/HOL/
   360     src/HOL/Library/GCD.thy ~> src/HOL/
   361     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   362     src/HOL/Library/Parity.thy ~> src/HOL/
   363     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   364     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   365     src/HOL/Real/Lubs.thy ~> src/HOL/
   366     src/HOL/Real/PReal.thy ~> src/HOL/
   367     src/HOL/Real/Rational.thy ~> src/HOL/
   368     src/HOL/Real/RComplete.thy ~> src/HOL/
   369     src/HOL/Real/RealDef.thy ~> src/HOL/
   370     src/HOL/Real/RealPow.thy ~> src/HOL/
   371     src/HOL/Real/Real.thy ~> src/HOL/
   372     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   373     src/HOL/Complex/Complex.thy ~> src/HOL/
   374     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   375     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   376     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   377     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   378     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   379     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   380     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   381     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   382     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   383     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   384     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   385     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   386     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   387     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   388     src/HOL/Real/Float ~> src/HOL/Library/
   389     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   390     src/HOL/Real/RealVector.thy ~> src/HOL/
   391 
   392     src/HOL/arith_data.ML ~> src/HOL/Tools
   393     src/HOL/hologic.ML ~> src/HOL/Tools
   394     src/HOL/simpdata.ML ~> src/HOL/Tools
   395     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   396     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   397     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   398     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   399     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   400     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   401     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   402 
   403     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   404     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   405     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   406     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   407     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   408     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   409 
   410 * If methods "eval" and "evaluation" encounter a structured proof
   411 state with !!/==>, only the conclusion is evaluated to True (if
   412 possible), avoiding strange error messages.
   413 
   414 * Method "sizechange" automates termination proofs using (a
   415 modification of) the size-change principle.  Requires SAT solver.  See
   416 src/HOL/ex/Termination.thy for examples.
   417 
   418 * Simplifier: simproc for let expressions now unfolds if bound
   419 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   420 
   421 * Method "arith": Linear arithmetic now ignores all inequalities when
   422 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   423 
   424 * New attribute "arith" for facts that should always be used
   425 automatically by arithmetic. It is intended to be used locally in
   426 proofs, e.g.
   427 
   428   assumes [arith]: "x > 0"
   429 
   430 Global usage is discouraged because of possible performance impact.
   431 
   432 * New classes "top" and "bot" with corresponding operations "top" and
   433 "bot" in theory Orderings; instantiation of class "complete_lattice"
   434 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   435 
   436 * Changed definition lemma "less_fun_def" in order to provide an
   437 instance for preorders on functions; use lemma "less_le" instead.
   438 INCOMPATIBILITY.
   439 
   440 * Theory Orderings: class "wellorder" moved here, with explicit
   441 induction rule "less_induct" as assumption.  For instantiation of
   442 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   443 INCOMPATIBILITY.
   444 
   445 * Theory Orderings: added class "preorder" as superclass of "order".
   446 INCOMPATIBILITY: Instantiation proofs for order, linorder
   447 etc. slightly changed.  Some theorems named order_class.* now named
   448 preorder_class.*.
   449 
   450 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   451 "diag" to "Id_on".
   452 
   453 * Theory Finite_Set: added a new fold combinator of type
   454 
   455   ('a => 'b => 'b) => 'b => 'a set => 'b
   456 
   457 Occasionally this is more convenient than the old fold combinator
   458 which is now defined in terms of the new one and renamed to
   459 fold_image.
   460 
   461 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   462 and "ring_simps" have been replaced by "algebra_simps" (which can be
   463 extended with further lemmas!).  At the moment both still exist but
   464 the former will disappear at some point.
   465 
   466 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   467 class recpower.  Type-specific simp rules for various recpower types
   468 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   469 
   470 rat_power_0    -> power_0
   471 rat_power_Suc  -> power_Suc
   472 realpow_0      -> power_0
   473 realpow_Suc    -> power_Suc
   474 complexpow_0   -> power_0
   475 complexpow_Suc -> power_Suc
   476 power_poly_0   -> power_0
   477 power_poly_Suc -> power_Suc
   478 
   479 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   480 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   481 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   482 of lemmas from Divides has been generalized from nat to class
   483 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   484 renames resulting from duplicate elimination:
   485 
   486     dvd_def_mod ~>          dvd_eq_mod_eq_0
   487     zero_dvd_iff ~>         dvd_0_left_iff
   488     dvd_0 ~>                dvd_0_right
   489     DIVISION_BY_ZERO_DIV ~> div_by_0
   490     DIVISION_BY_ZERO_MOD ~> mod_by_0
   491     mult_div ~>             div_mult_self2_is_id
   492     mult_mod ~>             mod_mult_self2_is_0
   493 
   494 * Theory IntDiv: removed many lemmas that are instances of class-based
   495 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   496 rename old lemmas as follows:
   497 
   498 dvd_diff               -> nat_dvd_diff
   499 dvd_zminus_iff         -> dvd_minus_iff
   500 mod_add1_eq            -> mod_add_eq
   501 mod_mult1_eq           -> mod_mult_right_eq
   502 mod_mult1_eq'          -> mod_mult_left_eq
   503 mod_mult_distrib_mod   -> mod_mult_eq
   504 nat_mod_add_left_eq    -> mod_add_left_eq
   505 nat_mod_add_right_eq   -> mod_add_right_eq
   506 nat_mod_div_trivial    -> mod_div_trivial
   507 nat_mod_mod_trivial    -> mod_mod_trivial
   508 zdiv_zadd_self1        -> div_add_self1
   509 zdiv_zadd_self2        -> div_add_self2
   510 zdiv_zmult_self1       -> div_mult_self2_is_id
   511 zdiv_zmult_self2       -> div_mult_self1_is_id
   512 zdvd_triv_left         -> dvd_triv_left
   513 zdvd_triv_right        -> dvd_triv_right
   514 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   515 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   516 zmod_zadd_left_eq      -> mod_add_left_eq
   517 zmod_zadd_right_eq     -> mod_add_right_eq
   518 zmod_zadd_self1        -> mod_add_self1
   519 zmod_zadd_self2        -> mod_add_self2
   520 zmod_zadd1_eq          -> mod_add_eq
   521 zmod_zdiff1_eq         -> mod_diff_eq
   522 zmod_zdvd_zmod         -> mod_mod_cancel
   523 zmod_zmod_cancel       -> mod_mod_cancel
   524 zmod_zmult_self1       -> mod_mult_self2_is_0
   525 zmod_zmult_self2       -> mod_mult_self1_is_0
   526 zmod_1                 -> mod_by_1
   527 zdiv_1                 -> div_by_1
   528 zdvd_abs1              -> abs_dvd_iff
   529 zdvd_abs2              -> dvd_abs_iff
   530 zdvd_refl              -> dvd_refl
   531 zdvd_trans             -> dvd_trans
   532 zdvd_zadd              -> dvd_add
   533 zdvd_zdiff             -> dvd_diff
   534 zdvd_zminus_iff        -> dvd_minus_iff
   535 zdvd_zminus2_iff       -> minus_dvd_iff
   536 zdvd_zmultD            -> dvd_mult_right
   537 zdvd_zmultD2           -> dvd_mult_left
   538 zdvd_zmult_mono        -> mult_dvd_mono
   539 zdvd_0_right           -> dvd_0_right
   540 zdvd_0_left            -> dvd_0_left_iff
   541 zdvd_1_left            -> one_dvd
   542 zminus_dvd_iff         -> minus_dvd_iff
   543 
   544 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   545 
   546 * The real numbers offer decimal input syntax: 12.34 is translated
   547 into 1234/10^2. This translation is not reversed upon output.
   548 
   549 * Theory Library/Polynomial defines an abstract type 'a poly of
   550 univariate polynomials with coefficients of type 'a.  In addition to
   551 the standard ring operations, it also supports div and mod.  Code
   552 generation is also supported, using list-style constructors.
   553 
   554 * Theory Library/Inner_Product defines a class of real_inner for real
   555 inner product spaces, with an overloaded operation inner :: 'a => 'a
   556 => real.  Class real_inner is a subclass of real_normed_vector from
   557 theory RealVector.
   558 
   559 * Theory Library/Product_Vector provides instances for the product
   560 type 'a * 'b of several classes from RealVector and Inner_Product.
   561 Definitions of addition, subtraction, scalar multiplication, norms,
   562 and inner products are included.
   563 
   564 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   565 addition to the field operations, numerals and case syntax are also
   566 supported.
   567 
   568 * Theory Library/Diagonalize provides constructive version of Cantor's
   569 first diagonalization argument.
   570 
   571 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   572 zlcm (for int); carried together from various gcd/lcm developements in
   573 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   574 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   575 may recover tupled syntax as follows:
   576 
   577     hide (open) const gcd
   578     abbreviation gcd where
   579       "gcd == (%(a, b). GCD.gcd a b)"
   580     notation (output)
   581       GCD.gcd ("gcd '(_, _')")
   582 
   583 The same works for lcm, zgcd, zlcm.
   584 
   585 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   586 instantiations for algebraic structures.  Removed some duplicate
   587 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   588 
   589 * ML antiquotation @{code} takes a constant as argument and generates
   590 corresponding code in background and inserts name of the corresponding
   591 resulting ML value/function/datatype constructor binding in place.
   592 All occurrences of @{code} with a single ML block are generated
   593 simultaneously.  Provides a generic and safe interface for
   594 instrumentalizing code generation.  See
   595 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   596 In future you ought to refrain from ad-hoc compiling generated SML
   597 code on the ML toplevel.  Note that (for technical reasons) @{code}
   598 cannot refer to constants for which user-defined serializations are
   599 set.  Refer to the corresponding ML counterpart directly in that
   600 cases.
   601 
   602 * Command 'rep_datatype': instead of theorem names the command now
   603 takes a list of terms denoting the constructors of the type to be
   604 represented as datatype.  The characteristic theorems have to be
   605 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   606 have disappeared in favour of existing ones:
   607 
   608     unit_induct                 ~> unit.induct
   609     prod_induct                 ~> prod.induct
   610     sum_induct                  ~> sum.induct
   611     Suc_Suc_eq                  ~> nat.inject
   612     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   613 
   614 
   615 *** HOL-Algebra ***
   616 
   617 * New locales for orders and lattices where the equivalence relation
   618 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   619 locales use a record structure with field eq for the equivalence.
   620 
   621 * New theory of factorial domains.
   622 
   623 * Units_l_inv and Units_r_inv are now simp rules by default.
   624 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   625 and/or r_inv will now also require deletion of these lemmas.
   626 
   627 * Renamed the following theorems, INCOMPATIBILITY:
   628 
   629 UpperD ~> Upper_memD
   630 LowerD ~> Lower_memD
   631 least_carrier ~> least_closed
   632 greatest_carrier ~> greatest_closed
   633 greatest_Lower_above ~> greatest_Lower_below
   634 one_zero ~> carrier_one_zero
   635 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   636 
   637 
   638 *** HOL-Nominal ***
   639 
   640 * Nominal datatypes can now contain type-variables.
   641 
   642 * Commands 'nominal_inductive' and 'equivariance' work with local
   643 theory targets.
   644 
   645 * Nominal primrec can now works with local theory targets and its
   646 specification syntax now conforms to the general format as seen in
   647 'inductive' etc.
   648 
   649 * Method "perm_simp" honours the standard simplifier attributes
   650 (no_asm), (no_asm_use) etc.
   651 
   652 * The new predicate #* is defined like freshness, except that on the
   653 left hand side can be a set or list of atoms.
   654 
   655 * Experimental command 'nominal_inductive2' derives strong induction
   656 principles for inductive definitions.  In contrast to
   657 'nominal_inductive', which can only deal with a fixed number of
   658 binders, it can deal with arbitrary expressions standing for sets of
   659 atoms to be avoided.  The only inductive definition we have at the
   660 moment that needs this generalisation is the typing rule for Lets in
   661 the algorithm W:
   662 
   663  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   664  -----------------------------------------------------------------
   665          Gamma |- Let x be t1 in t2 : T2
   666 
   667 In this rule one wants to avoid all the binders that are introduced by
   668 "close Gamma T1".  We are looking for other examples where this
   669 feature might be useful.  Please let us know.
   670 
   671 
   672 *** HOLCF ***
   673 
   674 * Reimplemented the simplification procedure for proving continuity
   675 subgoals.  The new simproc is extensible; users can declare additional
   676 continuity introduction rules with the attribute [cont2cont].
   677 
   678 * The continuity simproc now uses a different introduction rule for
   679 solving continuity subgoals on terms with lambda abstractions.  In
   680 some rare cases the new simproc may fail to solve subgoals that the
   681 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   682 Potential INCOMPATIBILITY.
   683 
   684 * Command 'fixrec': specification syntax now conforms to the general
   685 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   686 examples.  INCOMPATIBILITY.
   687 
   688 
   689 *** ZF ***
   690 
   691 * Proof of Zorn's Lemma for partial orders.
   692 
   693 
   694 *** ML ***
   695 
   696 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   697 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   698 depends on multithreading, so timouts will not work before Poly/ML
   699 5.2.1!
   700 
   701 * High-level support for concurrent ML programming, see
   702 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   703 particularly convenient to organize independent functional
   704 computations.  The concept of "synchronized variables" provides a
   705 higher-order interface for components with shared state, avoiding the
   706 delicate details of mutexes and condition variables.  (Requires
   707 Poly/ML 5.2.1 or later.)
   708 
   709 * ML bindings produced via Isar commands are stored within the Isar
   710 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   711 become thread-safe and work with undo as expected (concerning
   712 top-level bindings, not side-effects on global references).
   713 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   714 compiler at runtime; really global bindings need to be given outside a
   715 theory.  (Requires Poly/ML 5.2 or later.)
   716 
   717 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   718 context.  Top-level ML bindings are stored within the proof context in
   719 a purely sequential fashion, disregarding the nested proof structure.
   720 ML bindings introduced by 'ML_prf' are discarded at the end of the
   721 proof.  (Requires Poly/ML 5.2 or later.)
   722 
   723 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   724 and Method.setup, as well as Isar commands 'attribute_setup' and
   725 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   726 existing code accordingly, or use plain 'setup' together with old
   727 Method.add_method.
   728 
   729 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   730 to 'a -> thm, while results are always tagged with an authentic oracle
   731 name.  The Isar command 'oracle' is now polymorphic, no argument type
   732 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   733 accordingly.  Note that extra performance may be gained by producing
   734 the cterm carefully, avoiding slow Thm.cterm_of.
   735 
   736 * Simplified interface for defining document antiquotations via
   737 ThyOutput.antiquotation, ThyOutput.output, and optionally
   738 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   739 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   740 examples.
   741 
   742 * More systematic treatment of long names, abstract name bindings, and
   743 name space operations.  Basic operations on qualified names have been
   744 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   745 Long_Name.append.  Old type bstring has been mostly replaced by
   746 abstract type binding (see structure Binding), which supports precise
   747 qualification by packages and local theory targets, as well as proper
   748 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   749 bstring values into Binding.name, or better pass through abstract
   750 bindings everywhere.  See further src/Pure/General/long_name.ML,
   751 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   752 
   753 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   754 LocalTheory.note etc.) now refer to the *full* internal name, not the
   755 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   756 
   757 * Disposed old type and term read functions (Sign.read_def_typ,
   758 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   759 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   760 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   761 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   762 resort for legacy applications.
   763 
   764 * Disposed old declarations, tactics, tactic combinators that refer to
   765 the simpset or claset of an implicit theory (such as Addsimps,
   766 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   767 embedded ML text, or local_simpset_of with a proper context passed as
   768 explicit runtime argument.
   769 
   770 * Rules and tactics that read instantiations (read_instantiate,
   771 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   772 context, which is required for parsing and type-checking.  Moreover,
   773 the variables are specified as plain indexnames, not string encodings
   774 thereof.  INCOMPATIBILITY.
   775 
   776 * Generic Toplevel.add_hook interface allows to analyze the result of
   777 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   778 for theorem dependency output of transactions resulting in a new
   779 theory state.
   780 
   781 * ML antiquotations: block-structured compilation context indicated by
   782 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   783 
   784   @{binding name}                         - basic name binding
   785   @{let ?pat = term}                      - term abbreviation (HO matching)
   786   @{note name = fact}                     - fact abbreviation
   787   @{thm fact}                             - singleton fact (with attributes)
   788   @{thms fact}                            - general fact (with attributes)
   789   @{lemma prop by method}                 - singleton goal
   790   @{lemma prop by meth1 meth2}            - singleton goal
   791   @{lemma prop1 ... propN by method}      - general goal
   792   @{lemma prop1 ... propN by meth1 meth2} - general goal
   793   @{lemma (open) ...}                     - open derivation
   794 
   795 
   796 *** System ***
   797 
   798 * The Isabelle "emacs" tool provides a specific interface to invoke
   799 Proof General / Emacs, with more explicit failure if that is not
   800 installed (the old isabelle-interface script silently falls back on
   801 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   802 installation location of the Proof General distribution.
   803 
   804 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   805 the Isabelle process into a JVM/Scala application.  See
   806 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   807 process wrapper has been discontinued.)
   808 
   809 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   810 
   811 * Various status messages (with exact source position information) are
   812 emitted, if proper markup print mode is enabled.  This allows
   813 user-interface components to provide detailed feedback on internal
   814 prover operations.
   815 
   816 
   817 
   818 New in Isabelle2008 (June 2008)
   819 -------------------------------
   820 
   821 *** General ***
   822 
   823 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   824 and updated, with formally checked references as hyperlinks.
   825 
   826 * Theory loader: use_thy (and similar operations) no longer set the
   827 implicit ML context, which was occasionally hard to predict and in
   828 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   829 provides a proper context already.
   830 
   831 * Theory loader: old-style ML proof scripts being *attached* to a thy
   832 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   833 'use' within a theory file will do the job.
   834 
   835 * Name space merge now observes canonical order, i.e. the second space
   836 is inserted into the first one, while existing entries in the first
   837 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   838 swap theory imports.
   839 
   840 * Syntax: symbol \<chi> is now considered a letter.  Potential
   841 INCOMPATIBILITY in identifier syntax etc.
   842 
   843 * Outer syntax: string tokens no longer admit escaped white space,
   844 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   845 white space without escapes.
   846 
   847 * Outer syntax: string tokens may contain arbitrary character codes
   848 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   849 "foo_bar".
   850 
   851 
   852 *** Pure ***
   853 
   854 * Context-dependent token translations.  Default setup reverts locally
   855 fixed variables, and adds hilite markup for undeclared frees.
   856 
   857 * Unused theorems can be found using the new command 'unused_thms'.
   858 There are three ways of invoking it:
   859 
   860 (1) unused_thms
   861      Only finds unused theorems in the current theory.
   862 
   863 (2) unused_thms thy_1 ... thy_n -
   864      Finds unused theorems in the current theory and all of its ancestors,
   865      excluding the theories thy_1 ... thy_n and all of their ancestors.
   866 
   867 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   868      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   869      their ancestors, excluding the theories thy_1 ... thy_n and all of
   870      their ancestors.
   871 
   872 In order to increase the readability of the list produced by
   873 unused_thms, theorems that have been created by a particular instance
   874 of a theory command such as 'inductive' or 'function' are considered
   875 to belong to the same "group", meaning that if at least one theorem in
   876 this group is used, the other theorems in the same group are no longer
   877 reported as unused.  Moreover, if all theorems in the group are
   878 unused, only one theorem in the group is displayed.
   879 
   880 Note that proof objects have to be switched on in order for
   881 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   882 usually the case when using Proof General with the default settings).
   883 
   884 * Authentic naming of facts disallows ad-hoc overwriting of previous
   885 theorems within the same name space.  INCOMPATIBILITY, need to remove
   886 duplicate fact bindings, or even accidental fact duplications.  Note
   887 that tools may maintain dynamically scoped facts systematically, using
   888 PureThy.add_thms_dynamic.
   889 
   890 * Command 'hide' now allows to hide from "fact" name space as well.
   891 
   892 * Eliminated destructive theorem database, simpset, claset, and
   893 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   894 update of theories within ML code.
   895 
   896 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   897 INCOMPATIBILITY, object-logics depending on former Pure require
   898 additional setup PureThy.old_appl_syntax_setup; object-logics
   899 depending on former CPure need to refer to Pure.
   900 
   901 * Commands 'use' and 'ML' are now purely functional, operating on
   902 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   903 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   904 INCOMPATIBILITY.
   905 
   906 * Command 'setup': discontinued implicit version with ML reference.
   907 
   908 * Instantiation target allows for simultaneous specification of class
   909 instance operations together with an instantiation proof.
   910 Type-checking phase allows to refer to class operations uniformly.
   911 See src/HOL/Complex/Complex.thy for an Isar example and
   912 src/HOL/Library/Eval.thy for an ML example.
   913 
   914 * Indexing of literal facts: be more serious about including only
   915 facts from the visible specification/proof context, but not the
   916 background context (locale etc.).  Affects `prop` notation and method
   917 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   918 situations.
   919 
   920 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   921 "(open)" option, which used to expose internal bound variables to the
   922 proof text.
   923 
   924 * Isar statements: removed obsolete case "rule_context".
   925 INCOMPATIBILITY, better use explicit fixes/assumes.
   926 
   927 * Locale proofs: default proof step now includes 'unfold_locales';
   928 hence 'proof' without argument may be used to unfold locale
   929 predicates.
   930 
   931 
   932 *** Document preparation ***
   933 
   934 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   935 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   936 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   937 spot); renamed link color from "darkblue" to "linkcolor" (default
   938 value unchanged, can be redefined via \definecolor); no longer sets
   939 "a4paper" option (unnecessary or even intrusive).
   940 
   941 * Antiquotation @{lemma A method} proves proposition A by the given
   942 method (either a method name or a method name plus (optional) method
   943 arguments in parentheses) and prints A just like @{prop A}.
   944 
   945 
   946 *** HOL ***
   947 
   948 * New primrec package.  Specification syntax conforms in style to
   949 definition/function/....  No separate induction rule is provided.  The
   950 "primrec" command distinguishes old-style and new-style specifications
   951 by syntax.  The former primrec package is now named OldPrimrecPackage.
   952 When adjusting theories, beware: constants stemming from new-style
   953 primrec specifications have authentic syntax.
   954 
   955 * Metis prover is now an order of magnitude faster, and also works
   956 with multithreading.
   957 
   958 * Metis: the maximum number of clauses that can be produced from a
   959 theorem is now given by the attribute max_clauses.  Theorems that
   960 exceed this number are ignored, with a warning printed.
   961 
   962 * Sledgehammer no longer produces structured proofs by default. To
   963 enable, declare [[sledgehammer_full = true]].  Attributes
   964 reconstruction_modulus, reconstruction_sorts renamed
   965 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   966 
   967 * Method "induct_scheme" derives user-specified induction rules
   968 from well-founded induction and completeness of patterns. This factors
   969 out some operations that are done internally by the function package
   970 and makes them available separately.  See
   971 src/HOL/ex/Induction_Scheme.thy for examples.
   972 
   973 * More flexible generation of measure functions for termination
   974 proofs: Measure functions can be declared by proving a rule of the
   975 form "is_measure f" and giving it the [measure_function] attribute.
   976 The "is_measure" predicate is logically meaningless (always true), and
   977 just guides the heuristic.  To find suitable measure functions, the
   978 termination prover sets up the goal "is_measure ?f" of the appropriate
   979 type and generates all solutions by prolog-style backwards proof using
   980 the declared rules.
   981 
   982 This setup also deals with rules like 
   983 
   984   "is_measure f ==> is_measure (list_size f)"
   985 
   986 which accommodates nested datatypes that recurse through lists.
   987 Similar rules are predeclared for products and option types.
   988 
   989 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   990 
   991   INCOMPATIBILITIES:
   992 
   993   - Definitions of overloaded constants on sets have to be replaced by
   994     definitions on => and bool.
   995 
   996   - Some definitions of overloaded operators on sets can now be proved
   997     using the definitions of the operators on => and bool.  Therefore,
   998     the following theorems have been renamed:
   999 
  1000       subset_def   -> subset_eq
  1001       psubset_def  -> psubset_eq
  1002       set_diff_def -> set_diff_eq
  1003       Compl_def    -> Compl_eq
  1004       Sup_set_def  -> Sup_set_eq
  1005       Inf_set_def  -> Inf_set_eq
  1006       sup_set_def  -> sup_set_eq
  1007       inf_set_def  -> inf_set_eq
  1008 
  1009   - Due to the incompleteness of the HO unification algorithm, some
  1010     rules such as subst may require manual instantiation, if some of
  1011     the unknowns in the rule is a set.
  1012 
  1013   - Higher order unification and forward proofs:
  1014     The proof pattern
  1015 
  1016       have "P (S::'a set)" <...>
  1017       then have "EX S. P S" ..
  1018 
  1019     no longer works (due to the incompleteness of the HO unification
  1020     algorithm) and must be replaced by the pattern
  1021 
  1022       have "EX S. P S"
  1023       proof
  1024         show "P S" <...>
  1025       qed
  1026 
  1027   - Calculational reasoning with subst (or similar rules):
  1028     The proof pattern
  1029 
  1030       have "P (S::'a set)" <...>
  1031       also have "S = T" <...>
  1032       finally have "P T" .
  1033 
  1034     no longer works (for similar reasons as the previous example) and
  1035     must be replaced by something like
  1036 
  1037       have "P (S::'a set)" <...>
  1038       moreover have "S = T" <...>
  1039       ultimately have "P T" by simp
  1040 
  1041   - Tactics or packages written in ML code:
  1042     Code performing pattern matching on types via
  1043 
  1044       Type ("set", [T]) => ...
  1045 
  1046     must be rewritten. Moreover, functions like strip_type or
  1047     binder_types no longer return the right value when applied to a
  1048     type of the form
  1049 
  1050       T1 => ... => Tn => U => bool
  1051 
  1052     rather than
  1053 
  1054       T1 => ... => Tn => U set
  1055 
  1056 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1057 Wellfounded_Relations to theory Wellfounded.
  1058 
  1059 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1060 
  1061 * Class finite no longer treats UNIV as class parameter.  Use class
  1062 enum from theory Library/Enum instead to achieve a similar effect.
  1063 INCOMPATIBILITY.
  1064 
  1065 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1066 and "Cons".  INCOMPATIBILITY.
  1067 
  1068 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1069 Potential INCOMPATIBILITY.
  1070 
  1071 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1072 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1073 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1074 
  1075 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1076 the same name in theory Orderings:
  1077 
  1078   less_trans
  1079   less_linear
  1080   le_imp_less_or_eq
  1081   le_less_trans
  1082   less_le_trans
  1083   less_not_sym
  1084   less_asym
  1085 
  1086 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1087 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1088 and different variable names.
  1089 
  1090 * Library/Option_ord.thy: Canonical order on option type.
  1091 
  1092 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1093 finite maps.
  1094 
  1095 * Library/Countable.thy: Type class for countable types.
  1096 
  1097 * Theory Int: The representation of numerals has changed.  The infix
  1098 operator BIT and the bit datatype with constructors B0 and B1 have
  1099 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1100 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1101 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1102 accordingly.
  1103 
  1104 * Theory Nat: definition of <= and < on natural numbers no longer
  1105 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1106 le_def and less_def have disappeared.  Consider lemmas not_less
  1107 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1108 
  1109 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1110 (whose purpose mainly is for various fold_set functionals) have been
  1111 abandoned in favor of the existing algebraic classes
  1112 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1113 lower_semilattice (resp. upper_semilattice) and linorder.
  1114 INCOMPATIBILITY.
  1115 
  1116 * Theory Transitive_Closure: induct and cases rules now declare proper
  1117 case_names ("base" and "step").  INCOMPATIBILITY.
  1118 
  1119 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1120 lattices.  The form set-specific version is available as
  1121 Inductive.lfp_ordinal_induct_set.
  1122 
  1123 * Renamed theorems "power.simps" to "power_int.simps".
  1124 INCOMPATIBILITY.
  1125 
  1126 * Class semiring_div provides basic abstract properties of semirings
  1127 with division and modulo operations.  Subsumes former class dvd_mod.
  1128 
  1129 * Merged theories IntDef, Numeral and IntArith into unified theory
  1130 Int.  INCOMPATIBILITY.
  1131 
  1132 * Theory Library/Code_Index: type "index" now represents natural
  1133 numbers rather than integers.  INCOMPATIBILITY.
  1134 
  1135 * New class "uminus" with operation "uminus" (split of from class
  1136 "minus" which now only has operation "minus", binary).
  1137 INCOMPATIBILITY.
  1138 
  1139 * Constants "card", "internal_split", "option_map" now with authentic
  1140 syntax.  INCOMPATIBILITY.
  1141 
  1142 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1143 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1144 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1145 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1146 Sup_set_def, le_def, less_def, option_map_def now with object
  1147 equality.  INCOMPATIBILITY.
  1148 
  1149 * Records. Removed K_record, and replaced it by pure lambda term
  1150 %x. c. The simplifier setup is now more robust against eta expansion.
  1151 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1152 
  1153 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1154 
  1155 * Library/ListVector: new theory of arithmetic vector operations.
  1156 
  1157 * Library/Order_Relation: new theory of various orderings as sets of
  1158 pairs.  Defines preorders, partial orders, linear orders and
  1159 well-orders on sets and on types.
  1160 
  1161 
  1162 *** ZF ***
  1163 
  1164 * Renamed some theories to allow to loading both ZF and HOL in the
  1165 same session:
  1166 
  1167   Datatype  -> Datatype_ZF
  1168   Inductive -> Inductive_ZF
  1169   Int       -> Int_ZF
  1170   IntDiv    -> IntDiv_ZF
  1171   Nat       -> Nat_ZF
  1172   List      -> List_ZF
  1173   Main      -> Main_ZF
  1174 
  1175 INCOMPATIBILITY: ZF theories that import individual theories below
  1176 Main might need to be adapted.  Regular theory Main is still
  1177 available, as trivial extension of Main_ZF.
  1178 
  1179 
  1180 *** ML ***
  1181 
  1182 * ML within Isar: antiquotation @{const name} or @{const
  1183 name(typargs)} produces statically-checked Const term.
  1184 
  1185 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1186 (of the same name).  Removed obsolete print command.
  1187 
  1188 * Removed obsolete "use_legacy_bindings" function.
  1189 
  1190 * The ``print mode'' is now a thread-local value derived from a global
  1191 template (the former print_mode reference), thus access becomes
  1192 non-critical.  The global print_mode reference is for session
  1193 management only; user-code should use print_mode_value,
  1194 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1195 
  1196 * Functions system/system_out provide a robust way to invoke external
  1197 shell commands, with propagation of interrupts (requires Poly/ML
  1198 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1199 
  1200 
  1201 *** System ***
  1202 
  1203 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1204 in accordance with Proof General 3.7, which prefers GNU emacs.
  1205 
  1206 * isatool tty runs Isabelle process with plain tty interaction;
  1207 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1208 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1209 
  1210 * isatool browser now works with Cygwin as well, using general
  1211 "javapath" function defined in Isabelle process environment.
  1212 
  1213 * YXML notation provides a simple and efficient alternative to
  1214 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1215 isatool yxml as described in the Isabelle system manual.
  1216 
  1217 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1218 provides general wrapper for managing an Isabelle process in a robust
  1219 fashion, with ``cooked'' output from stdin/stderr.
  1220 
  1221 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1222 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1223 
  1224 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1225 way of changing the user's settings is via
  1226 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1227 script.
  1228 
  1229 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1230 cores of the underlying machine, which is a good starting point for
  1231 optimal performance tuning.  The corresponding usedir option -M allows
  1232 "max" as an alias for "0".  WARNING: does not work on certain versions
  1233 of Mac OS (with Poly/ML 5.1).
  1234 
  1235 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1236 adverse effect of Isabelle flooding interactive front-ends (notably
  1237 ProofGeneral / XEmacs).
  1238 
  1239 
  1240 
  1241 New in Isabelle2007 (November 2007)
  1242 -----------------------------------
  1243 
  1244 *** General ***
  1245 
  1246 * More uniform information about legacy features, notably a
  1247 warning/error of "Legacy feature: ...", depending on the state of the
  1248 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1249 legacy features will disappear eventually.
  1250 
  1251 * Theory syntax: the header format ``theory A = B + C:'' has been
  1252 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1253 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1254 
  1255 * Theory syntax: the old non-Isar theory file format has been
  1256 discontinued altogether.  Note that ML proof scripts may still be used
  1257 with Isar theories; migration is usually quite simple with the ML
  1258 function use_legacy_bindings.  INCOMPATIBILITY.
  1259 
  1260 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1261 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1262 quotes.
  1263 
  1264 * Theory loader: be more serious about observing the static theory
  1265 header specifications (including optional directories), but not the
  1266 accidental file locations of previously successful loads.  The strict
  1267 update policy of former update_thy is now already performed by
  1268 use_thy, so the former has been removed; use_thys updates several
  1269 theories simultaneously, just as 'imports' within a theory header
  1270 specification, but without merging the results.  Potential
  1271 INCOMPATIBILITY: may need to refine theory headers and commands
  1272 ROOT.ML which depend on load order.
  1273 
  1274 * Theory loader: optional support for content-based file
  1275 identification, instead of the traditional scheme of full physical
  1276 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1277 (cf. the system manual).  The new scheme allows to work with
  1278 non-finished theories in persistent session images, such that source
  1279 files may be moved later on without requiring reloads.
  1280 
  1281 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1282 file (with the same base name as the theory) are considered a legacy
  1283 feature, which will disappear eventually. Even now, the theory loader
  1284 no longer maintains dependencies on such files.
  1285 
  1286 * Syntax: the scope for resolving ambiguities via type-inference is
  1287 now limited to individual terms, instead of whole simultaneous
  1288 specifications as before. This greatly reduces the complexity of the
  1289 syntax module and improves flexibility by separating parsing and
  1290 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1291 'fixes' etc.) are required in rare situations.
  1292 
  1293 * Syntax: constants introduced by new-style packages ('definition',
  1294 'abbreviation' etc.) are passed through the syntax module in
  1295 ``authentic mode''. This means that associated mixfix annotations
  1296 really stick to such constants, independently of potential name space
  1297 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1298 trees are represented slightly differently, may need to adapt syntax
  1299 translations accordingly. Use CONST marker in 'translations' and
  1300 @{const_syntax} antiquotation in 'parse_translation' etc.
  1301 
  1302 * Legacy goal package: reduced interface to the bare minimum required
  1303 to keep existing proof scripts running.  Most other user-level
  1304 functions are now part of the OldGoals structure, which is *not* open
  1305 by default (consider isatool expandshort before open OldGoals).
  1306 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1307 these tend to cause confusion about the actual goal (!) context being
  1308 used here, which is not necessarily the same as the_context().
  1309 
  1310 * Command 'find_theorems': supports "*" wild-card in "name:"
  1311 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1312 support a specific search form (see ProofGeneral/CHANGES).
  1313 
  1314 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1315 by default, which means that "prems" (and also "fixed variables") are
  1316 suppressed from proof state output.  Note that the ProofGeneral
  1317 settings mechanism allows to change and save options persistently, but
  1318 older versions of Isabelle will fail to start up if a negative prems
  1319 limit is imposed.
  1320 
  1321 * Local theory targets may be specified by non-nested blocks of
  1322 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1323 contain definitions, theorems etc., including any derived mechanism
  1324 that has been implemented on top of these primitives.  This concept
  1325 generalizes the existing ``theorem (in ...)'' towards more versatility
  1326 and scalability.
  1327 
  1328 * Proof General interface: proper undo of final 'end' command;
  1329 discontinued Isabelle/classic mode (ML proof scripts).
  1330 
  1331 
  1332 *** Document preparation ***
  1333 
  1334 * Added antiquotation @{theory name} which prints the given name,
  1335 after checking that it refers to a valid ancestor theory in the
  1336 current context.
  1337 
  1338 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1339 check the given source text as ML type/structure, printing verbatim.
  1340 
  1341 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1342 "c args == rhs" given in the current context.  (Any number of
  1343 arguments may be given on the LHS.)
  1344 
  1345 
  1346 *** Pure ***
  1347 
  1348 * The 'class' package offers a combination of axclass and locale to
  1349 achieve Haskell-like type classes in Isabelle.  Definitions and
  1350 theorems within a class context produce both relative results (with
  1351 implicit parameters according to the locale context), and polymorphic
  1352 constants with qualified polymorphism (according to the class
  1353 context).  Within the body context of a 'class' target, a separate
  1354 syntax layer ("user space type system") takes care of converting
  1355 between global polymorphic consts and internal locale representation.
  1356 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1357 "isatool doc classes" provides a tutorial.
  1358 
  1359 * Generic code generator framework allows to generate executable
  1360 code for ML and Haskell (including Isabelle classes).  A short usage
  1361 sketch:
  1362 
  1363     internal compilation:
  1364         export_code <list of constants (term syntax)> in SML
  1365     writing SML code to a file:
  1366         export_code <list of constants (term syntax)> in SML <filename>
  1367     writing OCaml code to a file:
  1368         export_code <list of constants (term syntax)> in OCaml <filename>
  1369     writing Haskell code to a bunch of files:
  1370         export_code <list of constants (term syntax)> in Haskell <filename>
  1371 
  1372     evaluating closed propositions to True/False using code generation:
  1373         method ``eval''
  1374 
  1375 Reasonable default setup of framework in HOL.
  1376 
  1377 Theorem attributs for selecting and transforming function equations theorems:
  1378 
  1379     [code fun]:        select a theorem as function equation for a specific constant
  1380     [code fun del]:    deselect a theorem as function equation for a specific constant
  1381     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1382     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1383 
  1384 User-defined serializations (target in {SML, OCaml, Haskell}):
  1385 
  1386     code_const <and-list of constants (term syntax)>
  1387       {(target) <and-list of const target syntax>}+
  1388 
  1389     code_type <and-list of type constructors>
  1390       {(target) <and-list of type target syntax>}+
  1391 
  1392     code_instance <and-list of instances>
  1393       {(target)}+
  1394         where instance ::= <type constructor> :: <class>
  1395 
  1396     code_class <and_list of classes>
  1397       {(target) <and-list of class target syntax>}+
  1398         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1399 
  1400 code_instance and code_class only are effective to target Haskell.
  1401 
  1402 For example usage see src/HOL/ex/Codegenerator.thy and
  1403 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1404 generation from Isabelle/HOL theories is available via "isatool doc
  1405 codegen".
  1406 
  1407 * Code generator: consts in 'consts_code' Isar commands are now
  1408 referred to by usual term syntax (including optional type
  1409 annotations).
  1410 
  1411 * Command 'no_translations' removes translation rules from theory
  1412 syntax.
  1413 
  1414 * Overloaded definitions are now actually checked for acyclic
  1415 dependencies.  The overloading scheme is slightly more general than
  1416 that of Haskell98, although Isabelle does not demand an exact
  1417 correspondence to type class and instance declarations.
  1418 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1419 exotic versions of overloading -- at the discretion of the user!
  1420 
  1421 Polymorphic constants are represented via type arguments, i.e. the
  1422 instantiation that matches an instance against the most general
  1423 declaration given in the signature.  For example, with the declaration
  1424 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1425 as c(nat).  Overloading is essentially simultaneous structural
  1426 recursion over such type arguments.  Incomplete specification patterns
  1427 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1428 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1429 Command 'print_theory' outputs the normalized system of recursive
  1430 equations, see section "definitions".
  1431 
  1432 * Configuration options are maintained within the theory or proof
  1433 context (with name and type bool/int/string), providing a very simple
  1434 interface to a poor-man's version of general context data.  Tools may
  1435 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1436 these values using Config.get etc.  Users may change options via an
  1437 associated attribute of the same name.  This form of context
  1438 declaration works particularly well with commands 'declare' or
  1439 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1440 very easy to avoid global references, which would not observe Isar
  1441 toplevel undo/redo and fail to work with multithreading.
  1442 
  1443 Various global ML references of Pure and HOL have been turned into
  1444 configuration options:
  1445 
  1446   Unify.search_bound		unify_search_bound
  1447   Unify.trace_bound		unify_trace_bound
  1448   Unify.trace_simp		unify_trace_simp
  1449   Unify.trace_types		unify_trace_types
  1450   Simplifier.simp_depth_limit	simp_depth_limit
  1451   Blast.depth_limit		blast_depth_limit
  1452   DatatypeProp.dtK		datatype_distinctness_limit
  1453   fast_arith_neq_limit  	fast_arith_neq_limit
  1454   fast_arith_split_limit	fast_arith_split_limit
  1455 
  1456 * Named collections of theorems may be easily installed as context
  1457 data using the functor NamedThmsFun (see also
  1458 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1459 attributes; there is also a toplevel print command.  This facility is
  1460 just a common case of general context data, which is the preferred way
  1461 for anything more complex than just a list of facts in canonical
  1462 order.
  1463 
  1464 * Isar: command 'declaration' augments a local theory by generic
  1465 declaration functions written in ML.  This enables arbitrary content
  1466 being added to the context, depending on a morphism that tells the
  1467 difference of the original declaration context wrt. the application
  1468 context encountered later on.
  1469 
  1470 * Isar: proper interfaces for simplification procedures.  Command
  1471 'simproc_setup' declares named simprocs (with match patterns, and body
  1472 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1473 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1474 
  1475 * Isar: an extra pair of brackets around attribute declarations
  1476 abbreviates a theorem reference involving an internal dummy fact,
  1477 which will be ignored later --- only the effect of the attribute on
  1478 the background context will persist.  This form of in-place
  1479 declarations is particularly useful with commands like 'declare' and
  1480 'using', for example ``have A using [[simproc a]] by simp''.
  1481 
  1482 * Isar: method "assumption" (and implicit closing of subproofs) now
  1483 takes simple non-atomic goal assumptions into account: after applying
  1484 an assumption as a rule the resulting subgoals are solved by atomic
  1485 assumption steps.  This is particularly useful to finish 'obtain'
  1486 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1487 without referring to the original premise "!!x. P x ==> thesis" in the
  1488 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1489 more permissive.
  1490 
  1491 * Isar: implicit use of prems from the Isar proof context is
  1492 considered a legacy feature.  Common applications like ``have A .''
  1493 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1494 referencing facts explicitly here improves readability and
  1495 maintainability of proof texts.
  1496 
  1497 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1498 the obtained context from the course of reasoning!  For example:
  1499 
  1500   assume "EX x y. A x & B y"   -- "any previous fact"
  1501   then guess x and y by clarify
  1502 
  1503 This technique is potentially adventurous, depending on the facts and
  1504 proof tools being involved here.
  1505 
  1506 * Isar: known facts from the proof context may be specified as literal
  1507 propositions, using ASCII back-quote syntax.  This works wherever
  1508 named facts used to be allowed so far, in proof commands, proof
  1509 methods, attributes etc.  Literal facts are retrieved from the context
  1510 according to unification of type and term parameters.  For example,
  1511 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1512 theorems in the current context, then these are valid literal facts:
  1513 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1514 
  1515 There is also a proof method "fact" which does the same composition
  1516 for explicit goal states, e.g. the following proof texts coincide with
  1517 certain special cases of literal facts:
  1518 
  1519   have "A" by fact                 ==  note `A`
  1520   have "A ==> B" by fact           ==  note `A ==> B`
  1521   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1522   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1523 
  1524 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1525 outer syntax.  Thus symbolic identifiers may be used without
  1526 additional white space in declarations like this: ``assume *: A''.
  1527 
  1528 * Isar: 'print_facts' prints all local facts of the current context,
  1529 both named and unnamed ones.
  1530 
  1531 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1532 
  1533   def x == "t" and y == "u"
  1534 
  1535 * Isar: added command 'unfolding', which is structurally similar to
  1536 'using', but affects both the goal state and facts by unfolding given
  1537 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1538 'unfolded' attribute may be replaced by first-class proof text.
  1539 
  1540 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1541 and command 'unfolding' now all support object-level equalities
  1542 (potentially conditional).  The underlying notion of rewrite rule is
  1543 analogous to the 'rule_format' attribute, but *not* that of the
  1544 Simplifier (which is usually more generous).
  1545 
  1546 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1547 premises of a theorem by n. Useful in conjunction with drule.
  1548 
  1549 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1550 method expression within a sandbox consisting of the first N
  1551 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1552 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1553 simplifies all new goals that emerge from applying rule foo to the
  1554 originally first one.
  1555 
  1556 * Isar: schematic goals are no longer restricted to higher-order
  1557 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1558 expected.
  1559 
  1560 * Isar: the conclusion of a long theorem statement is now either
  1561 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1562 (essentially a disjunction of cases with local parameters and
  1563 assumptions).  The latter allows to express general elimination rules
  1564 adequately; in this notation common elimination rules look like this:
  1565 
  1566   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1567     assumes "EX x. P x"
  1568     obtains x where "P x"
  1569 
  1570   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1571     assumes "A & B"
  1572     obtains A and B
  1573 
  1574   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1575     assumes "A | B"
  1576     obtains
  1577       A
  1578     | B
  1579 
  1580 The subsequent classical rules even refer to the formal "thesis"
  1581 explicitly:
  1582 
  1583   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1584     obtains "~ thesis"
  1585 
  1586   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1587     obtains "thesis ==> something"
  1588 
  1589 The actual proof of an 'obtains' statement is analogous to that of the
  1590 Isar proof element 'obtain', only that there may be several cases.
  1591 Optional case names may be specified in parentheses; these will be
  1592 available both in the present proof and as annotations in the
  1593 resulting rule, for later use with the 'cases' method (cf. attribute
  1594 case_names).
  1595 
  1596 * Isar: the assumptions of a long theorem statement are available as
  1597 "assms" fact in the proof context.  This is more appropriate than the
  1598 (historical) "prems", which refers to all assumptions of the current
  1599 context, including those from the target locale, proof body etc.
  1600 
  1601 * Isar: 'print_statement' prints theorems from the current theory or
  1602 proof context in long statement form, according to the syntax of a
  1603 top-level lemma.
  1604 
  1605 * Isar: 'obtain' takes an optional case name for the local context
  1606 introduction rule (default "that").
  1607 
  1608 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1609 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1610 to occur.
  1611 
  1612 * Pure: syntax "CONST name" produces a fully internalized constant
  1613 according to the current context.  This is particularly useful for
  1614 syntax translations that should refer to internal constant
  1615 representations independently of name spaces.
  1616 
  1617 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1618 instead of "FOO ". This allows multiple binder declarations to coexist
  1619 in the same context.  INCOMPATIBILITY.
  1620 
  1621 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1622 primitive that also works in a locale context (both for constants and
  1623 fixed variables). Type declaration and internal syntactic representation
  1624 of given constants retrieved from the context. Likewise, the
  1625 'no_notation' command allows to remove given syntax annotations from the
  1626 current context.
  1627 
  1628 * Isar/locales: new derived specification elements 'axiomatization',
  1629 'definition', 'abbreviation', which support type-inference, admit
  1630 object-level specifications (equality, equivalence).  See also the
  1631 isar-ref manual.  Examples:
  1632 
  1633   axiomatization
  1634     eq  (infix "===" 50) where
  1635     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1636 
  1637   definition "f x y = x + y + 1"
  1638   definition g where "g x = f x x"
  1639 
  1640   abbreviation
  1641     neq  (infix "=!=" 50) where
  1642     "x =!= y == ~ (x === y)"
  1643 
  1644 These specifications may be also used in a locale context.  Then the
  1645 constants being introduced depend on certain fixed parameters, and the
  1646 constant name is qualified by the locale base name.  An internal
  1647 abbreviation takes care for convenient input and output, making the
  1648 parameters implicit and using the original short name.  See also
  1649 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1650 entities from a monomorphic theory.
  1651 
  1652 Presently, abbreviations are only available 'in' a target locale, but
  1653 not inherited by general import expressions.  Also note that
  1654 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1655 'translations' in common applications.  The "no_abbrevs" print mode
  1656 prevents folding of abbreviations in term output.
  1657 
  1658 Concrete syntax is attached to specified constants in internal form,
  1659 independently of name spaces.  The parse tree representation is
  1660 slightly different -- use 'notation' instead of raw 'syntax', and
  1661 'translations' with explicit "CONST" markup to accommodate this.
  1662 
  1663 * Pure/Isar: unified syntax for new-style specification mechanisms
  1664 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1665 full type inference and dummy patterns ("_").  For example:
  1666 
  1667   definition "K x _ = x"
  1668 
  1669   inductive conj for A B
  1670   where "A ==> B ==> conj A B"
  1671 
  1672 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1673 the current context.  Print mode "no_abbrevs" prevents inversion of
  1674 abbreviations on output.
  1675 
  1676 * Isar/locales: improved parameter handling: use of locales "var" and
  1677 "struct" no longer necessary; - parameter renamings are no longer
  1678 required to be injective.  For example, this allows to define
  1679 endomorphisms as locale endom = homom mult mult h.
  1680 
  1681 * Isar/locales: changed the way locales with predicates are defined.
  1682 Instead of accumulating the specification, the imported expression is
  1683 now an interpretation.  INCOMPATIBILITY: different normal form of
  1684 locale expressions.  In particular, in interpretations of locales with
  1685 predicates, goals repesenting already interpreted fragments are not
  1686 removed automatically.  Use methods `intro_locales' and
  1687 `unfold_locales'; see below.
  1688 
  1689 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1690 provide backward reasoning on locales predicates.  The methods are
  1691 aware of interpretations and discharge corresponding goals.
  1692 `intro_locales' is less aggressive then `unfold_locales' and does not
  1693 unfold predicates to assumptions.
  1694 
  1695 * Isar/locales: the order in which locale fragments are accumulated
  1696 has changed.  This enables to override declarations from fragments due
  1697 to interpretations -- for example, unwanted simp rules.
  1698 
  1699 * Isar/locales: interpretation in theories and proof contexts has been
  1700 extended.  One may now specify (and prove) equations, which are
  1701 unfolded in interpreted theorems.  This is useful for replacing
  1702 defined concepts (constants depending on locale parameters) by
  1703 concepts already existing in the target context.  Example:
  1704 
  1705   interpretation partial_order ["op <= :: [int, int] => bool"]
  1706     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1707 
  1708 Typically, the constant `partial_order.less' is created by a
  1709 definition specification element in the context of locale
  1710 partial_order.
  1711 
  1712 * Method "induct": improved internal context management to support
  1713 local fixes and defines on-the-fly. Thus explicit meta-level
  1714 connectives !!  and ==> are rarely required anymore in inductive goals
  1715 (using object-logic connectives for this purpose has been long
  1716 obsolete anyway). Common proof patterns are explained in
  1717 src/HOL/Induct/Common_Patterns.thy, see also
  1718 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1719 examples.
  1720 
  1721 * Method "induct": improved handling of simultaneous goals. Instead of
  1722 introducing object-level conjunction, the statement is now split into
  1723 several conclusions, while the corresponding symbolic cases are nested
  1724 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1725 see src/HOL/Induct/Common_Patterns.thy, for example.
  1726 
  1727 * Method "induct": mutual induction rules are now specified as a list
  1728 of rule sharing the same induction cases. HOL packages usually provide
  1729 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1730 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1731 mutual induction rules differently, i.e. like this:
  1732 
  1733   (induct rule: foo_bar.inducts)
  1734   (induct set: foo bar)
  1735   (induct pred: foo bar)
  1736   (induct type: foo bar)
  1737 
  1738 The ML function ProjectRule.projections turns old-style rules into the
  1739 new format.
  1740 
  1741 * Method "coinduct": dual of induction, see
  1742 src/HOL/Library/Coinductive_List.thy for various examples.
  1743 
  1744 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1745 considered a legacy feature.
  1746 
  1747 * Attribute "symmetric" produces result with standardized schematic
  1748 variables (index 0).  Potential INCOMPATIBILITY.
  1749 
  1750 * Simplifier: by default the simplifier trace only shows top level
  1751 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1752 default. Thus there is less danger of being flooded by the trace. The
  1753 trace indicates where parts have been suppressed.
  1754   
  1755 * Provers/classical: removed obsolete classical version of elim_format
  1756 attribute; classical elim/dest rules are now treated uniformly when
  1757 manipulating the claset.
  1758 
  1759 * Provers/classical: stricter checks to ensure that supplied intro,
  1760 dest and elim rules are well-formed; dest and elim rules must have at
  1761 least one premise.
  1762 
  1763 * Provers/classical: attributes dest/elim/intro take an optional
  1764 weight argument for the rule (just as the Pure versions).  Weights are
  1765 ignored by automated tools, but determine the search order of single
  1766 rule steps.
  1767 
  1768 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1769 where the body does not mention the bound variable.  Note that dummy
  1770 patterns implicitly depend on their context of bounds, which makes
  1771 "{_. _}" match any set comprehension as expected.  Potential
  1772 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1773 constant "_idtdummy" in the binding position.
  1774 
  1775 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1776 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1777 for example "A -> B" => "Pi A (%_. B)".
  1778 
  1779 * Pure: 'class_deps' command visualizes the subclass relation, using
  1780 the graph browser tool.
  1781 
  1782 * Pure: 'print_theory' now suppresses certain internal declarations by
  1783 default; use '!' option for full details.
  1784 
  1785 
  1786 *** HOL ***
  1787 
  1788 * Method "metis" proves goals by applying the Metis general-purpose
  1789 resolution prover (see also http://gilith.com/software/metis/).
  1790 Examples are in the directory MetisExamples.  WARNING: the
  1791 Isabelle/HOL-Metis integration does not yet work properly with
  1792 multi-threading.
  1793   
  1794 * Command 'sledgehammer' invokes external automatic theorem provers as
  1795 background processes.  It generates calls to the "metis" method if
  1796 successful. These can be pasted into the proof.  Users do not have to
  1797 wait for the automatic provers to return.  WARNING: does not really
  1798 work with multi-threading.
  1799 
  1800 * New "auto_quickcheck" feature tests outermost goal statements for
  1801 potential counter-examples.  Controlled by ML references
  1802 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1803 5000 milliseconds).  Fails silently if statements is outside of
  1804 executable fragment, or any other codgenerator problem occurs.
  1805 
  1806 * New constant "undefined" with axiom "undefined x = undefined".
  1807 
  1808 * Added class "HOL.eq", allowing for code generation with polymorphic
  1809 equality.
  1810 
  1811 * Some renaming of class constants due to canonical name prefixing in
  1812 the new 'class' package:
  1813 
  1814     HOL.abs ~> HOL.abs_class.abs
  1815     HOL.divide ~> HOL.divide_class.divide
  1816     0 ~> HOL.zero_class.zero
  1817     1 ~> HOL.one_class.one
  1818     op + ~> HOL.plus_class.plus
  1819     op - ~> HOL.minus_class.minus
  1820     uminus ~> HOL.minus_class.uminus
  1821     op * ~> HOL.times_class.times
  1822     op < ~> HOL.ord_class.less
  1823     op <= > HOL.ord_class.less_eq
  1824     Nat.power ~> Power.power_class.power
  1825     Nat.size ~> Nat.size_class.size
  1826     Numeral.number_of ~> Numeral.number_class.number_of
  1827     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1828     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1829     Orderings.min ~> Orderings.ord_class.min
  1830     Orderings.max ~> Orderings.ord_class.max
  1831     Divides.op div ~> Divides.div_class.div
  1832     Divides.op mod ~> Divides.div_class.mod
  1833     Divides.op dvd ~> Divides.div_class.dvd
  1834 
  1835 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1836 
  1837 a) User-defined constants using any of the names "plus", "minus",
  1838 "times", "less" or "less_eq". The standard syntax translations for
  1839 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1840 names.
  1841 
  1842 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1843 INCOMPATIBILITY: use more specific names.
  1844 
  1845 c) Permutative equations (e.g. "a + b = b + a")
  1846 Since the change of names also changes the order of terms, permutative
  1847 rewrite rules may get applied in a different order. Experience shows
  1848 that this is rarely the case (only two adaptions in the whole Isabelle
  1849 distribution).  INCOMPATIBILITY: rewrite proofs
  1850 
  1851 d) ML code directly refering to constant names
  1852 This in general only affects hand-written proof tactics, simprocs and
  1853 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1854 Consider using @{const_name} antiquotation.
  1855 
  1856 * New class "default" with associated constant "default".
  1857 
  1858 * Function "sgn" is now overloaded and available on int, real, complex
  1859 (and other numeric types), using class "sgn".  Two possible defs of
  1860 sgn are given as equational assumptions in the classes sgn_if and
  1861 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1862 INCOMPATIBILITY.
  1863 
  1864 * Locale "partial_order" now unified with class "order" (cf. theory
  1865 Orderings), added parameter "less".  INCOMPATIBILITY.
  1866 
  1867 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1868 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1869 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1870 
  1871 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1872 changed order of proof goals in instance proofs.
  1873 
  1874 * The transitivity reasoner for partial and linear orders is set up
  1875 for classes "order" and "linorder".  Instances of the reasoner are available
  1876 in all contexts importing or interpreting the corresponding locales.
  1877 Method "order" invokes the reasoner separately; the reasoner
  1878 is also integrated with the Simplifier as a solver.  Diagnostic
  1879 command 'print_orders' shows the available instances of the reasoner
  1880 in the current context.
  1881 
  1882 * Localized monotonicity predicate in theory "Orderings"; integrated
  1883 lemmas max_of_mono and min_of_mono with this predicate.
  1884 INCOMPATIBILITY.
  1885 
  1886 * Formulation of theorem "dense" changed slightly due to integration
  1887 with new class dense_linear_order.
  1888 
  1889 * Uniform lattice theory development in HOL.
  1890 
  1891     constants "meet" and "join" now named "inf" and "sup"
  1892     constant "Meet" now named "Inf"
  1893 
  1894     classes "meet_semilorder" and "join_semilorder" now named
  1895       "lower_semilattice" and "upper_semilattice"
  1896     class "lorder" now named "lattice"
  1897     class "comp_lat" now named "complete_lattice"
  1898 
  1899     Instantiation of lattice classes allows explicit definitions
  1900     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1901 
  1902   INCOMPATIBILITY.  Theorem renames:
  1903 
  1904     meet_left_le            ~> inf_le1
  1905     meet_right_le           ~> inf_le2
  1906     join_left_le            ~> sup_ge1
  1907     join_right_le           ~> sup_ge2
  1908     meet_join_le            ~> inf_sup_ord
  1909     le_meetI                ~> le_infI
  1910     join_leI                ~> le_supI
  1911     le_meet                 ~> le_inf_iff
  1912     le_join                 ~> ge_sup_conv
  1913     meet_idempotent         ~> inf_idem
  1914     join_idempotent         ~> sup_idem
  1915     meet_comm               ~> inf_commute
  1916     join_comm               ~> sup_commute
  1917     meet_leI1               ~> le_infI1
  1918     meet_leI2               ~> le_infI2
  1919     le_joinI1               ~> le_supI1
  1920     le_joinI2               ~> le_supI2
  1921     meet_assoc              ~> inf_assoc
  1922     join_assoc              ~> sup_assoc
  1923     meet_left_comm          ~> inf_left_commute
  1924     meet_left_idempotent    ~> inf_left_idem
  1925     join_left_comm          ~> sup_left_commute
  1926     join_left_idempotent    ~> sup_left_idem
  1927     meet_aci                ~> inf_aci
  1928     join_aci                ~> sup_aci
  1929     le_def_meet             ~> le_iff_inf
  1930     le_def_join             ~> le_iff_sup
  1931     join_absorp2            ~> sup_absorb2
  1932     join_absorp1            ~> sup_absorb1
  1933     meet_absorp1            ~> inf_absorb1
  1934     meet_absorp2            ~> inf_absorb2
  1935     meet_join_absorp        ~> inf_sup_absorb
  1936     join_meet_absorp        ~> sup_inf_absorb
  1937     distrib_join_le         ~> distrib_sup_le
  1938     distrib_meet_le         ~> distrib_inf_le
  1939 
  1940     add_meet_distrib_left   ~> add_inf_distrib_left
  1941     add_join_distrib_left   ~> add_sup_distrib_left
  1942     is_join_neg_meet        ~> is_join_neg_inf
  1943     is_meet_neg_join        ~> is_meet_neg_sup
  1944     add_meet_distrib_right  ~> add_inf_distrib_right
  1945     add_join_distrib_right  ~> add_sup_distrib_right
  1946     add_meet_join_distribs  ~> add_sup_inf_distribs
  1947     join_eq_neg_meet        ~> sup_eq_neg_inf
  1948     meet_eq_neg_join        ~> inf_eq_neg_sup
  1949     add_eq_meet_join        ~> add_eq_inf_sup
  1950     meet_0_imp_0            ~> inf_0_imp_0
  1951     join_0_imp_0            ~> sup_0_imp_0
  1952     meet_0_eq_0             ~> inf_0_eq_0
  1953     join_0_eq_0             ~> sup_0_eq_0
  1954     neg_meet_eq_join        ~> neg_inf_eq_sup
  1955     neg_join_eq_meet        ~> neg_sup_eq_inf
  1956     join_eq_if              ~> sup_eq_if
  1957 
  1958     mono_meet               ~> mono_inf
  1959     mono_join               ~> mono_sup
  1960     meet_bool_eq            ~> inf_bool_eq
  1961     join_bool_eq            ~> sup_bool_eq
  1962     meet_fun_eq             ~> inf_fun_eq
  1963     join_fun_eq             ~> sup_fun_eq
  1964     meet_set_eq             ~> inf_set_eq
  1965     join_set_eq             ~> sup_set_eq
  1966     meet1_iff               ~> inf1_iff
  1967     meet2_iff               ~> inf2_iff
  1968     meet1I                  ~> inf1I
  1969     meet2I                  ~> inf2I
  1970     meet1D1                 ~> inf1D1
  1971     meet2D1                 ~> inf2D1
  1972     meet1D2                 ~> inf1D2
  1973     meet2D2                 ~> inf2D2
  1974     meet1E                  ~> inf1E
  1975     meet2E                  ~> inf2E
  1976     join1_iff               ~> sup1_iff
  1977     join2_iff               ~> sup2_iff
  1978     join1I1                 ~> sup1I1
  1979     join2I1                 ~> sup2I1
  1980     join1I1                 ~> sup1I1
  1981     join2I2                 ~> sup1I2
  1982     join1CI                 ~> sup1CI
  1983     join2CI                 ~> sup2CI
  1984     join1E                  ~> sup1E
  1985     join2E                  ~> sup2E
  1986 
  1987     is_meet_Meet            ~> is_meet_Inf
  1988     Meet_bool_def           ~> Inf_bool_def
  1989     Meet_fun_def            ~> Inf_fun_def
  1990     Meet_greatest           ~> Inf_greatest
  1991     Meet_lower              ~> Inf_lower
  1992     Meet_set_def            ~> Inf_set_def
  1993 
  1994     Sup_def                 ~> Sup_Inf
  1995     Sup_bool_eq             ~> Sup_bool_def
  1996     Sup_fun_eq              ~> Sup_fun_def
  1997     Sup_set_eq              ~> Sup_set_def
  1998 
  1999     listsp_meetI            ~> listsp_infI
  2000     listsp_meet_eq          ~> listsp_inf_eq
  2001 
  2002     meet_min                ~> inf_min
  2003     join_max                ~> sup_max
  2004 
  2005 * Added syntactic class "size"; overloaded constant "size" now has
  2006 type "'a::size ==> bool"
  2007 
  2008 * Internal reorganisation of `size' of datatypes: size theorems
  2009 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2010 simplification rules by default!); theorems "prod.size" now named
  2011 "*.size".
  2012 
  2013 * Class "div" now inherits from class "times" rather than "type".
  2014 INCOMPATIBILITY.
  2015 
  2016 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2017 Linorder etc.  have disappeared; operations defined in terms of
  2018 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2019 
  2020 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2021 
  2022 * HOL-Word: New extensive library and type for generic, fixed size
  2023 machine words, with arithemtic, bit-wise, shifting and rotating
  2024 operations, reflection into int, nat, and bool lists, automation for
  2025 linear arithmetic (by automatic reflection into nat or int), including
  2026 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2027 arithmetic type classes, supporting automatic simplification of
  2028 numerals on all operations.
  2029 
  2030 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2031 
  2032 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2033 
  2034 * Code generator library theories:
  2035   - Code_Integer represents HOL integers by big integer literals in target
  2036     languages.
  2037   - Code_Char represents HOL characters by character literals in target
  2038     languages.
  2039   - Code_Char_chr like Code_Char, but also offers treatment of character
  2040     codes; includes Code_Integer.
  2041   - Executable_Set allows to generate code for finite sets using lists.
  2042   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2043     denominator).
  2044   - Executable_Real implements a subset of real numbers, namly those
  2045     representable by rational numbers.
  2046   - Efficient_Nat implements natural numbers by integers, which in general will
  2047     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2048     includes Code_Integer.
  2049   - Code_Index provides an additional datatype index which is mapped to
  2050     target-language built-in integers.
  2051   - Code_Message provides an additional datatype message_string which is isomorphic to
  2052     strings; messages are mapped to target-language strings.
  2053 
  2054 * New package for inductive predicates
  2055 
  2056   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2057 
  2058     inductive
  2059       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2060       for z_1 :: U_1 and ... and z_n :: U_m
  2061     where
  2062       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2063     | ...
  2064 
  2065   with full support for type-inference, rather than
  2066 
  2067     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2068 
  2069     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2070     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2071 
  2072     inductive "s z_1 ... z_m"
  2073     intros
  2074       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2075       ...
  2076 
  2077   For backward compatibility, there is a wrapper allowing inductive
  2078   sets to be defined with the new package via
  2079 
  2080     inductive_set
  2081       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2082       for z_1 :: U_1 and ... and z_n :: U_m
  2083     where
  2084       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2085     | ...
  2086 
  2087   or
  2088 
  2089     inductive_set
  2090       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2091       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2092       for z_1 :: U_1 and ... and z_n :: U_m
  2093     where
  2094       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2095     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2096     | ...
  2097 
  2098   if the additional syntax "p ..." is required.
  2099 
  2100   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2101   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2102 
  2103   INCOMPATIBILITIES:
  2104 
  2105   - Since declaration and definition of inductive sets or predicates
  2106     is no longer separated, abbreviations involving the newly
  2107     introduced sets or predicates must be specified together with the
  2108     introduction rules after the 'where' keyword (see above), rather
  2109     than before the actual inductive definition.
  2110 
  2111   - The variables in induction and elimination rules are now
  2112     quantified in the order of their occurrence in the introduction
  2113     rules, rather than in alphabetical order. Since this may break
  2114     some proofs, these proofs either have to be repaired, e.g. by
  2115     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2116     statements of the form
  2117 
  2118       case (rule_i a_i_1 ... a_i_{k_i})
  2119 
  2120     or the old order of quantification has to be restored by explicitly adding
  2121     meta-level quantifiers in the introduction rules, i.e.
  2122 
  2123       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2124 
  2125   - The format of the elimination rules is now
  2126 
  2127       p z_1 ... z_m x_1 ... x_n ==>
  2128         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2129         ==> ... ==> P
  2130 
  2131     for predicates and
  2132 
  2133       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2134         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2135         ==> ... ==> P
  2136 
  2137     for sets rather than
  2138 
  2139       x : s z_1 ... z_m ==>
  2140         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2141         ==> ... ==> P
  2142 
  2143     This may require terms in goals to be expanded to n-tuples
  2144     (e.g. using case_tac or simplification with the split_paired_all
  2145     rule) before the above elimination rule is applicable.
  2146 
  2147   - The elimination or case analysis rules for (mutually) inductive
  2148     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2149     list of rules "p_1_..._p_k.elims" is no longer available.
  2150 
  2151 * New package "function"/"fun" for general recursive functions,
  2152 supporting mutual and nested recursion, definitions in local contexts,
  2153 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2154 for small examples, and the separate tutorial on the function
  2155 package. The old recdef "package" is still available as before, but
  2156 users are encouraged to use the new package.
  2157 
  2158 * Method "lexicographic_order" automatically synthesizes termination
  2159 relations as lexicographic combinations of size measures. 
  2160 
  2161 * Case-expressions allow arbitrary constructor-patterns (including
  2162 "_") and take their order into account, like in functional
  2163 programming.  Internally, this is translated into nested
  2164 case-expressions; missing cases are added and mapped to the predefined
  2165 constant "undefined". In complicated cases printing may no longer show
  2166 the original input but the internal form. Lambda-abstractions allow
  2167 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2168 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2169 variable.
  2170 
  2171 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2172 is an abbreviation for "of_nat :: nat => int". The simplification
  2173 rules for "of_nat" have been changed to work like "int" did
  2174 previously.  Potential INCOMPATIBILITY:
  2175   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2176   - of_nat_diff and of_nat_mult are no longer default simp rules
  2177 
  2178 * Method "algebra" solves polynomial equations over (semi)rings using
  2179 Groebner bases. The (semi)ring structure is defined by locales and the
  2180 tool setup depends on that generic context. Installing the method for
  2181 a specific type involves instantiating the locale and possibly adding
  2182 declarations for computation on the coefficients.  The method is
  2183 already instantiated for natural numbers and for the axiomatic class
  2184 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2185 CALCULEMUS 2007 for the general principles underlying this
  2186 architecture of context-aware proof-tools.
  2187 
  2188 * Method "ferrack" implements quantifier elimination over
  2189 special-purpose dense linear orders using locales (analogous to
  2190 "algebra"). The method is already installed for class
  2191 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2192 rat, etc.
  2193 
  2194 * Former constant "List.op @" now named "List.append".  Use ML
  2195 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2196 circumvent possible incompatibilities when working on ML level.
  2197 
  2198 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2199 
  2200 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2201 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2202 
  2203 * New syntax for Haskell-like list comprehension (input only), eg.
  2204 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2205 
  2206 * The special syntax for function "filter" has changed from [x :
  2207 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2208 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2209 
  2210 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2211 defined on nat only, as an abbreviation for [a..<Suc b]
  2212 INCOMPATIBILITY.
  2213 
  2214 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2215 
  2216 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2217 
  2218 * New lemma collection field_simps (an extension of ring_simps) for
  2219 manipulating (in)equations involving division. Multiplies with all
  2220 denominators that can be proved to be non-zero (in equations) or
  2221 positive/negative (in inequations).
  2222 
  2223 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2224 have been improved and renamed to ring_simps, group_simps and
  2225 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2226 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2227 
  2228 * Theory Library/Commutative_Ring: switched from recdef to function
  2229 package; constants add, mul, pow now curried.  Infix syntax for
  2230 algebraic operations.
  2231 
  2232 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2233 INCOMPATIBILITY.
  2234 
  2235 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2236 INCOMPATIBILITY.
  2237 
  2238 * HOL/records: generalised field-update to take a function on the
  2239 field rather than the new value: r(|A := x|) is translated to A_update
  2240 (K x) r The K-combinator that is internally used is called K_record.
  2241 INCOMPATIBILITY: Usage of the plain update functions has to be
  2242 adapted.
  2243  
  2244 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2245 * x = 0, which are required for a semiring.  Richer structures do not
  2246 inherit from semiring_0 anymore, because this property is a theorem
  2247 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2248 there is more to prove, but this is mostly trivial.
  2249 
  2250 * Class "recpower" is generalized to arbitrary monoids, not just
  2251 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2252 commutativity or semiring properties additionally.
  2253 
  2254 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2255 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2256 better use 'abbreviation'.
  2257 
  2258 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2259 
  2260 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2261 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2262 significant changes for setting up numeral syntax for types:
  2263   - New constants Numeral.pred and Numeral.succ instead
  2264       of former Numeral.bin_pred and Numeral.bin_succ.
  2265   - Use integer operations instead of bin_add, bin_mult and so on.
  2266   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2267   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2268 
  2269 See src/HOL/Integ/IntArith.thy for an example setup.
  2270 
  2271 * Command 'normal_form' computes the normal form of a term that may
  2272 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2273 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2274 heavy-duty computations because the functions are compiled to ML
  2275 first.  Correspondingly, a method "normalization" is provided.  See
  2276 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2277 
  2278 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2279 25 like -->); output depends on the "iff" print_mode, the default is
  2280 "A = B" (with priority 50).
  2281 
  2282 * Relations less (<) and less_eq (<=) are also available on type bool.
  2283 Modified syntax to disallow nesting without explicit parentheses,
  2284 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2285 INCOMPATIBILITY.
  2286 
  2287 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2288 
  2289 * Relation composition operator "op O" now has precedence 75 and binds
  2290 stronger than union and intersection. INCOMPATIBILITY.
  2291 
  2292 * The old set interval syntax "{m..n(}" (and relatives) has been
  2293 removed.  Use "{m..<n}" (and relatives) instead.
  2294 
  2295 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2296 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2297 ``declare [[simproc del: neq]]''.
  2298 
  2299 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2300 True/False.
  2301 
  2302 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2303 
  2304 * Theorem setsum_mult renamed to setsum_right_distrib.
  2305 
  2306 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2307 ``rule'' method.
  2308 
  2309 * Reimplemented methods "sat" and "satx", with several improvements:
  2310 goals no longer need to be stated as "<prems> ==> False", equivalences
  2311 (i.e. "=" on type bool) are handled, variable names of the form
  2312 "lit_<n>" are no longer reserved, significant speedup.
  2313 
  2314 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2315 zChaff is still supported as well.
  2316 
  2317 * 'inductive' and 'datatype': provide projections of mutual rules,
  2318 bundled as foo_bar.inducts;
  2319 
  2320 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2321 Library.
  2322 
  2323 * Library: moved theory Accessible_Part to main HOL.
  2324 
  2325 * Library: added theory Coinductive_List of potentially infinite lists
  2326 as greatest fixed-point.
  2327 
  2328 * Library: added theory AssocList which implements (finite) maps as
  2329 association lists.
  2330 
  2331 * Method "evaluation" solves goals (i.e. a boolean expression)
  2332 efficiently by compiling it to ML.  The goal is "proved" (via an
  2333 oracle) if it evaluates to True.
  2334 
  2335 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2336 also when invoked by the simplifier.  This results in the Simplifier
  2337 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2338 Configuration option fast_arith_split_limit=0 recovers the old
  2339 behavior.
  2340 
  2341 * Support for hex (0x20) and binary (0b1001) numerals.
  2342 
  2343 * New method: reify eqs (t), where eqs are equations for an
  2344 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2345 parameter, computes a term s::'b and a list xs::'a list and proves the
  2346 theorem I xs s = t. This is also known as reification or quoting. The
  2347 resulting theorem is applied to the subgoal to substitute t with I xs
  2348 s.  If t is omitted, the subgoal itself is reified.
  2349 
  2350 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2351 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2352 where f is supposed to be a computable function (in the sense of code
  2353 generattion). The method uses reify to compute s and xs as above then
  2354 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2355 r and finally gets the theorem t = r, which is again applied to the
  2356 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2357 
  2358 * Reflection: Automatic reification now handels binding, an example is
  2359 available in src/HOL/ex/ReflectionEx.thy
  2360 
  2361 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2362 command 'statespace' that is similar to 'record', but introduces an
  2363 abstract specification based on the locale infrastructure instead of
  2364 HOL types.  This leads to extra flexibility in composing state spaces,
  2365 in particular multiple inheritance and renaming of components.
  2366 
  2367 
  2368 *** HOL-Complex ***
  2369 
  2370 * Hyperreal: Functions root and sqrt are now defined on negative real
  2371 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2372 Nonnegativity side conditions have been removed from many lemmas, so
  2373 that more subgoals may now be solved by simplification; potential
  2374 INCOMPATIBILITY.
  2375 
  2376 * Real: new type classes formalize real normed vector spaces and
  2377 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2378 and norm :: 'a => real.
  2379 
  2380 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2381 reals into other types. The overloaded constant Reals :: 'a set is now
  2382 defined as range of_real; potential INCOMPATIBILITY.
  2383 
  2384 * Real: proper support for ML code generation, including 'quickcheck'.
  2385 Reals are implemented as arbitrary precision rationals.
  2386 
  2387 * Hyperreal: Several constants that previously worked only for the
  2388 reals have been generalized, so they now work over arbitrary vector
  2389 spaces. Type annotations may need to be added in some cases; potential
  2390 INCOMPATIBILITY.
  2391 
  2392   Infinitesimal  :: ('a::real_normed_vector) star set
  2393   HFinite        :: ('a::real_normed_vector) star set
  2394   HInfinite      :: ('a::real_normed_vector) star set
  2395   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2396   monad          :: ('a::real_normed_vector) star => 'a star set
  2397   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2398   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2399   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2400   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2401   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2402   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2403   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2404   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2405   sgn            :: 'a::real_normed_vector => 'a
  2406   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2407 
  2408 * Complex: Some complex-specific constants are now abbreviations for
  2409 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2410 hnorm.  Other constants have been entirely removed in favor of the
  2411 polymorphic versions (INCOMPATIBILITY):
  2412 
  2413   approx        <-- capprox
  2414   HFinite       <-- CFinite
  2415   HInfinite     <-- CInfinite
  2416   Infinitesimal <-- CInfinitesimal
  2417   monad         <-- cmonad
  2418   galaxy        <-- cgalaxy
  2419   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2420   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2421   (ns)deriv     <-- (ns)cderiv
  2422 
  2423 
  2424 *** HOL-Algebra ***
  2425 
  2426 * Formalisation of ideals and the quotient construction over rings.
  2427 
  2428 * Order and lattice theory no longer based on records.
  2429 INCOMPATIBILITY.
  2430 
  2431 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2432 greatest_closed.  INCOMPATIBILITY.
  2433 
  2434 * Method algebra is now set up via an attribute.  For examples see
  2435 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2436 of algebraic structures.
  2437 
  2438 * Renamed theory CRing to Ring.
  2439 
  2440 
  2441 *** HOL-Nominal ***
  2442 
  2443 * Substantial, yet incomplete support for nominal datatypes (binding
  2444 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2445 src/HOL/Nominal/Examples.  Prospective users should consult
  2446 http://isabelle.in.tum.de/nominal/
  2447 
  2448 
  2449 *** ML ***
  2450 
  2451 * ML basics: just one true type int, which coincides with IntInf.int
  2452 (even on SML/NJ).
  2453 
  2454 * ML within Isar: antiquotations allow to embed statically-checked
  2455 formal entities in the source, referring to the context available at
  2456 compile-time.  For example:
  2457 
  2458 ML {* @{sort "{zero,one}"} *}
  2459 ML {* @{typ "'a => 'b"} *}
  2460 ML {* @{term "%x. x"} *}
  2461 ML {* @{prop "x == y"} *}
  2462 ML {* @{ctyp "'a => 'b"} *}
  2463 ML {* @{cterm "%x. x"} *}
  2464 ML {* @{cprop "x == y"} *}
  2465 ML {* @{thm asm_rl} *}
  2466 ML {* @{thms asm_rl} *}
  2467 ML {* @{type_name c} *}
  2468 ML {* @{type_syntax c} *}
  2469 ML {* @{const_name c} *}
  2470 ML {* @{const_syntax c} *}
  2471 ML {* @{context} *}
  2472 ML {* @{theory} *}
  2473 ML {* @{theory Pure} *}
  2474 ML {* @{theory_ref} *}
  2475 ML {* @{theory_ref Pure} *}
  2476 ML {* @{simpset} *}
  2477 ML {* @{claset} *}
  2478 ML {* @{clasimpset} *}
  2479 
  2480 The same works for sources being ``used'' within an Isar context.
  2481 
  2482 * ML in Isar: improved error reporting; extra verbosity with
  2483 ML_Context.trace enabled.
  2484 
  2485 * Pure/General/table.ML: the join operations now works via exceptions
  2486 DUP/SAME instead of type option. This is simpler in simple cases, and
  2487 admits slightly more efficient complex applications.
  2488 
  2489 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2490 use Context.generic instead of just theory.
  2491 
  2492 * Pure: datatype Context.generic joins theory/Proof.context and
  2493 provides some facilities for code that works in either kind of
  2494 context, notably GenericDataFun for uniform theory and proof data.
  2495 
  2496 * Pure: simplified internal attribute type, which is now always
  2497 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2498 local (Proof.context) attributes have been discontinued, while
  2499 minimizing code duplication. Thm.rule_attribute and
  2500 Thm.declaration_attribute build canonical attributes; see also structure
  2501 Context for further operations on Context.generic, notably
  2502 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2503 declarations and definitions.
  2504 
  2505 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2506 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2507 init only required for impure data. INCOMPATIBILITY: empty really need
  2508 to be empty (no dependencies on theory content!)
  2509 
  2510 * Pure/kernel: consts certification ignores sort constraints given in
  2511 signature declarations. (This information is not relevant to the
  2512 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2513 potential INCOMPATIBILITY.
  2514 
  2515 * Pure: axiomatic type classes are now purely definitional, with
  2516 explicit proofs of class axioms and super class relations performed
  2517 internally. See Pure/axclass.ML for the main internal interfaces --
  2518 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2519 AxClass.axiomatize_class/classrel/arity supersede
  2520 Sign.add_classes/classrel/arities.
  2521 
  2522 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2523 global/local versions on theory vs. Proof.context have been
  2524 discontinued; Attrib.syntax and Method.syntax have been adapted
  2525 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2526 attributes, methods, etc.
  2527 
  2528 * Pure: several functions of signature "... -> theory -> theory * ..."
  2529 have been reoriented to "... -> theory -> ... * theory" in order to
  2530 allow natural usage in combination with the ||>, ||>>, |-> and
  2531 fold_map combinators.
  2532 
  2533 * Pure: official theorem names (closed derivations) and additional
  2534 comments (tags) are now strictly separate.  Name hints -- which are
  2535 maintained as tags -- may be attached any time without affecting the
  2536 derivation.
  2537 
  2538 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2539 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2540 achieve the old behaviour.
  2541 
  2542 * Pure: the "Goal" constant is now called "prop", supporting a
  2543 slightly more general idea of ``protecting'' meta-level rule
  2544 statements.
  2545 
  2546 * Pure: Logic.(un)varify only works in a global context, which is now
  2547 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2548 Logic.legacy_(un)varify as temporary workaround.
  2549 
  2550 * Pure: structure Name provides scalable operations for generating
  2551 internal variable names, notably Name.variants etc.  This replaces
  2552 some popular functions from term.ML:
  2553 
  2554   Term.variant		->  Name.variant
  2555   Term.variantlist	->  Name.variant_list
  2556   Term.invent_names	->  Name.invent_list
  2557 
  2558 Note that low-level renaming rarely occurs in new code -- operations
  2559 from structure Variable are used instead (see below).
  2560 
  2561 * Pure: structure Variable provides fundamental operations for proper
  2562 treatment of fixed/schematic variables in a context.  For example,
  2563 Variable.import introduces fixes for schematics of given facts and
  2564 Variable.export reverses the effect (up to renaming) -- this replaces
  2565 various freeze_thaw operations.
  2566 
  2567 * Pure: structure Goal provides simple interfaces for
  2568 init/conclude/finish and tactical prove operations (replacing former
  2569 Tactic.prove).  Goal.prove is the canonical way to prove results
  2570 within a given context; Goal.prove_global is a degraded version for
  2571 theory level goals, including a global Drule.standard.  Note that
  2572 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2573 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2574 in a locale context).
  2575 
  2576 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2577 and type checking (Syntax.check_term etc.), with common combinations
  2578 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2579 which are considered legacy and await removal.
  2580 
  2581 * Pure/Syntax: generic interfaces for type unchecking
  2582 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2583 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2584 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2585 available for convenience, but refer to the very same operations using
  2586 a mere theory instead of a full context.
  2587 
  2588 * Isar: simplified treatment of user-level errors, using exception
  2589 ERROR of string uniformly.  Function error now merely raises ERROR,
  2590 without any side effect on output channels.  The Isar toplevel takes
  2591 care of proper display of ERROR exceptions.  ML code may use plain
  2592 handle/can/try; cat_error may be used to concatenate errors like this:
  2593 
  2594   ... handle ERROR msg => cat_error msg "..."
  2595 
  2596 Toplevel ML code (run directly or through the Isar toplevel) may be
  2597 embedded into the Isar toplevel with exception display/debug like
  2598 this:
  2599 
  2600   Isar.toplevel (fn () => ...)
  2601 
  2602 INCOMPATIBILITY, removed special transform_error facilities, removed
  2603 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2604 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2605 -- use plain ERROR instead.
  2606 
  2607 * Isar: theory setup now has type (theory -> theory), instead of a
  2608 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2609 
  2610 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2611 ProofContext.debug/verbose flags.
  2612 
  2613 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2614 theory before entering a proof state.  Transactions now always see a
  2615 quasi-functional intermediate checkpoint, both in interactive and
  2616 batch mode.
  2617 
  2618 * Isar: simplified interfaces for outer syntax.  Renamed
  2619 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2620 OuterSyntax.add_parsers -- this functionality is now included in
  2621 OuterSyntax.command etc.  INCOMPATIBILITY.
  2622 
  2623 * Simplifier: the simpset of a running simplification process now
  2624 contains a proof context (cf. Simplifier.the_context), which is the
  2625 very context that the initial simpset has been retrieved from (by
  2626 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2627 (solver, looper etc.) may depend on arbitrary proof data.
  2628 
  2629 * Simplifier.inherit_context inherits the proof context (plus the
  2630 local bounds) of the current simplification process; any simproc
  2631 etc. that calls the Simplifier recursively should do this!  Removed
  2632 former Simplifier.inherit_bounds, which is already included here --
  2633 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2634 specify an explicit context using Simplifier.context/theory_context.
  2635 
  2636 * Simplifier/Classical Reasoner: more abstract interfaces
  2637 change_simpset/claset for modifying the simpset/claset reference of a
  2638 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2639 INCOMPATIBILITY.
  2640 
  2641 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2642 "Trueprop" etc.
  2643 
  2644 
  2645 *** System ***
  2646 
  2647 * settings: the default heap location within ISABELLE_HOME_USER now
  2648 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2649 Isabelle installations.
  2650 
  2651 * isabelle-process: option -S (secure mode) disables some critical
  2652 operations, notably runtime compilation and evaluation of ML source
  2653 code.
  2654 
  2655 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2656 
  2657 * Support for parallel execution, using native multicore support of
  2658 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2659 independent theories, according to the given theory header
  2660 specifications. The maximum number of worker threads is specified via
  2661 usedir option -M or the "max-threads" setting in Proof General. A
  2662 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2663 to 6 on a 8-core machine.  User-code needs to observe certain
  2664 guidelines for thread-safe programming, see appendix A in the Isar
  2665 Implementation manual.
  2666 
  2667 
  2668 
  2669 New in Isabelle2005 (October 2005)
  2670 ----------------------------------
  2671 
  2672 *** General ***
  2673 
  2674 * Theory headers: the new header syntax for Isar theories is
  2675 
  2676   theory <name>
  2677   imports <theory1> ... <theoryN>
  2678   uses <file1> ... <fileM>
  2679   begin
  2680 
  2681 where the 'uses' part is optional.  The previous syntax
  2682 
  2683   theory <name> = <theory1> + ... + <theoryN>:
  2684 
  2685 will disappear in the next release.  Use isatool fixheaders to convert
  2686 existing theory files.  Note that there is no change in ancient
  2687 non-Isar theories now, but these will disappear soon.
  2688 
  2689 * Theory loader: parent theories can now also be referred to via
  2690 relative and absolute paths.
  2691 
  2692 * Command 'find_theorems' searches for a list of criteria instead of a
  2693 list of constants. Known criteria are: intro, elim, dest, name:string,
  2694 simp:term, and any term. Criteria can be preceded by '-' to select
  2695 theorems that do not match. Intro, elim, dest select theorems that
  2696 match the current goal, name:s selects theorems whose fully qualified
  2697 name contain s, and simp:term selects all simplification rules whose
  2698 lhs match term.  Any other term is interpreted as pattern and selects
  2699 all theorems matching the pattern. Available in ProofGeneral under
  2700 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2701 
  2702   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2703 
  2704 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2705 matching the current goal as introduction rule and not having "HOL."
  2706 in their name (i.e. not being defined in theory HOL).
  2707 
  2708 * Command 'thms_containing' has been discontinued in favour of
  2709 'find_theorems'; INCOMPATIBILITY.
  2710 
  2711 * Communication with Proof General is now 8bit clean, which means that
  2712 Unicode text in UTF-8 encoding may be used within theory texts (both
  2713 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2714 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2715 
  2716   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2717   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2718 
  2719 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2720 Classical Reasoner.  Typical big applications run around 2 times
  2721 faster.
  2722 
  2723 
  2724 *** Document preparation ***
  2725 
  2726 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2727 of raw sources.  Only those symbols that do not require additional
  2728 LaTeX packages (depending on comments in isabellesym.sty) are
  2729 displayed properly, everything else is left verbatim.  isatool display
  2730 and isatool print are used as front ends (these are subject to the
  2731 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2732 
  2733 * Command tags control specific markup of certain regions of text,
  2734 notably folding and hiding.  Predefined tags include "theory" (for
  2735 theory begin and end), "proof" for proof commands, and "ML" for
  2736 commands involving ML code; the additional tags "visible" and
  2737 "invisible" are unused by default.  Users may give explicit tag
  2738 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2739 interpretation of tags is determined by the LaTeX job during document
  2740 preparation: see option -V of isatool usedir, or options -n and -t of
  2741 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2742 \isadroptag.
  2743 
  2744 Several document versions may be produced at the same time via isatool
  2745 usedir (the generated index.html will link all of them).  Typical
  2746 specifications include ''-V document=theory,proof,ML'' to present
  2747 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2748 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2749 these parts without any formal replacement text.  The Isabelle site
  2750 default settings produce ''document'' and ''outline'' versions as
  2751 specified above.
  2752 
  2753 * Several new antiquotations:
  2754 
  2755   @{term_type term} prints a term with its type annotated;
  2756 
  2757   @{typeof term} prints the type of a term;
  2758 
  2759   @{const const} is the same as @{term const}, but checks that the
  2760   argument is a known logical constant;
  2761 
  2762   @{term_style style term} and @{thm_style style thm} print a term or
  2763   theorem applying a "style" to it
  2764 
  2765   @{ML text}
  2766 
  2767 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2768 definitions, equations, inequations etc., 'concl' printing only the
  2769 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2770 to print the specified premise.  TermStyle.add_style provides an ML
  2771 interface for introducing further styles.  See also the "LaTeX Sugar"
  2772 document practical applications.  The ML antiquotation prints
  2773 type-checked ML expressions verbatim.
  2774 
  2775 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2776 and 'text' support optional locale specification '(in loc)', which
  2777 specifies the default context for interpreting antiquotations.  For
  2778 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2779 
  2780 * Option 'locale=NAME' of antiquotations specifies an alternative
  2781 context interpreting the subsequent argument.  For example: @{thm
  2782 [locale=lattice] inf_assoc}.
  2783 
  2784 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2785 a proof context.
  2786 
  2787 * Proper output of antiquotations for theory commands involving a
  2788 proof context (such as 'locale' or 'theorem (in loc) ...').
  2789 
  2790 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2791 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2792 
  2793 * isatool usedir: new option -C (default true) controls whether option
  2794 -D should include a copy of the original document directory; -C false
  2795 prevents unwanted effects such as copying of administrative CVS data.
  2796 
  2797 
  2798 *** Pure ***
  2799 
  2800 * Considerably improved version of 'constdefs' command.  Now performs
  2801 automatic type-inference of declared constants; additional support for
  2802 local structure declarations (cf. locales and HOL records), see also
  2803 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2804 sequential dependencies of definitions within a single 'constdefs'
  2805 section; moreover, the declared name needs to be an identifier.  If
  2806 all fails, consider to fall back on 'consts' and 'defs' separately.
  2807 
  2808 * Improved indexed syntax and implicit structures.  First of all,
  2809 indexed syntax provides a notational device for subscripted
  2810 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2811 expressions.  Secondly, in a local context with structure
  2812 declarations, number indexes \<^sub>n or the empty index (default
  2813 number 1) refer to a certain fixed variable implicitly; option
  2814 show_structs controls printing of implicit structures.  Typical
  2815 applications of these concepts involve record types and locales.
  2816 
  2817 * New command 'no_syntax' removes grammar declarations (and
  2818 translations) resulting from the given syntax specification, which is
  2819 interpreted in the same manner as for the 'syntax' command.
  2820 
  2821 * 'Advanced' translation functions (parse_translation etc.) may depend
  2822 on the signature of the theory context being presently used for
  2823 parsing/printing, see also isar-ref manual.
  2824 
  2825 * Improved 'oracle' command provides a type-safe interface to turn an
  2826 ML expression of type theory -> T -> term into a primitive rule of
  2827 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2828 is already included here); see also FOL/ex/IffExample.thy;
  2829 INCOMPATIBILITY.
  2830 
  2831 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2832 before); "cI" is no longer bound, use "c.intro" instead.
  2833 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2834 axclasses vs. locales.
  2835 
  2836 * Improved internal renaming of symbolic identifiers -- attach primes
  2837 instead of base 26 numbers.
  2838 
  2839 * New flag show_question_marks controls printing of leading question
  2840 marks in schematic variable names.
  2841 
  2842 * In schematic variable names, *any* symbol following \<^isub> or
  2843 \<^isup> is now treated as part of the base name.  For example, the
  2844 following works without printing of awkward ".0" indexes:
  2845 
  2846   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2847     by simp
  2848 
  2849 * Inner syntax includes (*(*nested*) comments*).
  2850 
  2851 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2852 annotations as "(00...)".
  2853 
  2854 * Clear separation of logical types and nonterminals, where the latter
  2855 may only occur in 'syntax' specifications or type abbreviations.
  2856 Before that distinction was only partially implemented via type class
  2857 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2858 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2859 exotic syntax specifications may require further adaption
  2860 (e.g. Cube/Cube.thy).
  2861 
  2862 * Removed obsolete type class "logic", use the top sort {} instead.
  2863 Note that non-logical types should be declared as 'nonterminals'
  2864 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2865 specifications.
  2866 
  2867 * Attributes 'induct' and 'cases': type or set names may now be
  2868 locally fixed variables as well.
  2869 
  2870 * Simplifier: can now control the depth to which conditional rewriting
  2871 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2872 Limit.
  2873 
  2874 * Simplifier: simplification procedures may now take the current
  2875 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2876 interface), which is very useful for calling the Simplifier
  2877 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2878 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2879 low-level mk_simproc no longer applies Logic.varify internally, to
  2880 allow for use in a context of fixed variables.
  2881 
  2882 * thin_tac now works even if the assumption being deleted contains !!
  2883 or ==>.  More generally, erule now works even if the major premise of
  2884 the elimination rule contains !! or ==>.
  2885 
  2886 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2887 
  2888 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2889 from Pure, which contains all common declarations already.  Both
  2890 theories are defined via plain Isabelle/Isar .thy files.
  2891 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2892 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2893 use isatool fixcpure to adapt your theory and ML sources.
  2894 
  2895 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2896 selections of theorems in named facts via index ranges.
  2897 
  2898 * 'print_theorems': in theory mode, really print the difference
  2899 wrt. the last state (works for interactive theory development only),
  2900 in proof mode print all local facts (cf. 'print_facts');
  2901 
  2902 * 'hide': option '(open)' hides only base names.
  2903 
  2904 * More efficient treatment of intermediate checkpoints in interactive
  2905 theory development.
  2906 
  2907 * Code generator is now invoked via code_module (incremental code
  2908 generation) and code_library (modular code generation, ML structures
  2909 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2910 must be quoted when used as identifiers.
  2911 
  2912 * New 'value' command for reading, evaluating and printing terms using
  2913 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2914 quoted when used as identifier.
  2915 
  2916 
  2917 *** Locales ***
  2918 
  2919 * New commands for the interpretation of locale expressions in
  2920 theories (1), locales (2) and proof contexts (3).  These generate
  2921 proof obligations from the expression specification.  After the
  2922 obligations have been discharged, theorems of the expression are added
  2923 to the theory, target locale or proof context.  The synopsis of the
  2924 commands is a follows:
  2925 
  2926   (1) interpretation expr inst
  2927   (2) interpretation target < expr
  2928   (3) interpret expr inst
  2929 
  2930 Interpretation in theories and proof contexts require a parameter
  2931 instantiation of terms from the current context.  This is applied to
  2932 specifications and theorems of the interpreted expression.
  2933 Interpretation in locales only permits parameter renaming through the
  2934 locale expression.  Interpretation is smart in that interpretations
  2935 that are active already do not occur in proof obligations, neither are
  2936 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2937 inspect active interpretations of a particular locale.  For details,
  2938 see the Isar Reference manual.  Examples can be found in
  2939 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2940 
  2941 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2942 'interpret' instead.
  2943 
  2944 * New context element 'constrains' for adding type constraints to
  2945 parameters.
  2946 
  2947 * Context expressions: renaming of parameters with syntax
  2948 redeclaration.
  2949 
  2950 * Locale declaration: 'includes' disallowed.
  2951 
  2952 * Proper static binding of attribute syntax -- i.e. types / terms /
  2953 facts mentioned as arguments are always those of the locale definition
  2954 context, independently of the context of later invocations.  Moreover,
  2955 locale operations (renaming and type / term instantiation) are applied
  2956 to attribute arguments as expected.
  2957 
  2958 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2959 actual attributes; rare situations may require Attrib.attribute to
  2960 embed those attributes into Attrib.src that lack concrete syntax.
  2961 Attribute implementations need to cooperate properly with the static
  2962 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2963 Attrib.XXX_thm etc. already do the right thing without further
  2964 intervention.  Only unusual applications -- such as "where" or "of"
  2965 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2966 on the context and the facts involved -- may have to assign parsed
  2967 values to argument tokens explicitly.
  2968 
  2969 * Changed parameter management in theorem generation for long goal
  2970 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2971 theorem statement in rare situations.
  2972 
  2973 * Locale inspection command 'print_locale' omits notes elements.  Use
  2974 'print_locale!' to have them included in the output.
  2975 
  2976 
  2977 *** Provers ***
  2978 
  2979 * Provers/hypsubst.ML: improved version of the subst method, for
  2980 single-step rewriting: it now works in bound variable contexts. New is
  2981 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2982 rewrite a different subterm than the original subst method, which is
  2983 still available as 'simplesubst'.
  2984 
  2985 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2986 and quasi orders.
  2987 
  2988 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2989 reflexive-transitive closure of relations.
  2990 
  2991 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2992 limit (previously hard-coded with a value of 20) user-definable.
  2993 
  2994 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2995 is peformed already.  Object-logics merely need to finish their
  2996 initial simpset configuration as before.  INCOMPATIBILITY.
  2997 
  2998 
  2999 *** HOL ***
  3000 
  3001 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3002 
  3003   syntax (epsilon)
  3004     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3005 
  3006 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3007 and x-symbol; use option '-m epsilon' to get it actually printed.
  3008 Moreover, the mathematically important symbolic identifier \<epsilon>
  3009 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3010 
  3011 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3012 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3013 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3014 support corresponding Isar calculations.
  3015 
  3016 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3017 instead of ":".
  3018 
  3019 * theory SetInterval: changed the syntax for open intervals:
  3020 
  3021   Old       New
  3022   {..n(}    {..<n}
  3023   {)n..}    {n<..}
  3024   {m..n(}   {m..<n}
  3025   {)m..n}   {m<..n}
  3026   {)m..n(}  {m<..<n}
  3027 
  3028 The old syntax is still supported but will disappear in the next
  3029 release.  For conversion use the following Emacs search and replace
  3030 patterns (these are not perfect but work quite well):
  3031 
  3032   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3033   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3034 
  3035 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3036 equalities in commutative rings; method 'algebra' provides a generic
  3037 interface.
  3038 
  3039 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3040 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3041 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3042 be a tuple pattern.
  3043 
  3044 Some new syntax forms are available:
  3045 
  3046   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3047   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3048   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3049   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3050 
  3051 The latter form "\<Sum>x < k. e" used to be based on a separate
  3052 function "Summation", which has been discontinued.
  3053 
  3054 * theory Finite_Set: in structured induction proofs, the insert case
  3055 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3056 (insert F x)'.
  3057 
  3058 * The 'refute' command has been extended to support a much larger
  3059 fragment of HOL, including axiomatic type classes, constdefs and
  3060 typedefs, inductive datatypes and recursion.
  3061 
  3062 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3063 Requires zChaff with proof generation to be installed.  See
  3064 HOL/ex/SAT_Examples.thy for examples.
  3065 
  3066 * Datatype induction via method 'induct' now preserves the name of the
  3067 induction variable. For example, when proving P(xs::'a list) by
  3068 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3069 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3070 in unstructured proof scripts.
  3071 
  3072 * Reworked implementation of records.  Improved scalability for
  3073 records with many fields, avoiding performance problems for type
  3074 inference. Records are no longer composed of nested field types, but
  3075 of nested extension types. Therefore the record type only grows linear
  3076 in the number of extensions and not in the number of fields.  The
  3077 top-level (users) view on records is preserved.  Potential
  3078 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3079 old record representation. The type generated for a record is called
  3080 <record_name>_ext_type.
  3081 
  3082 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3083 proofs triggered by a record definition or a simproc (if
  3084 quick_and_dirty is enabled).  Definitions of large records can take
  3085 quite long.
  3086 
  3087 New simproc record_upd_simproc for simplification of multiple record
  3088 updates enabled by default.  Moreover, trivial updates are also
  3089 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3090 occasionally, since simplification is more powerful by default.
  3091 
  3092 * typedef: proper support for polymorphic sets, which contain extra
  3093 type-variables in the term.
  3094 
  3095 * Simplifier: automatically reasons about transitivity chains
  3096 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3097 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3098 old proofs break occasionally as simplification may now solve more
  3099 goals than previously.
  3100 
  3101 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3102 present.  Works for all partial orders (class "order"), in particular
  3103 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3104 just like y <= x.
  3105 
  3106 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3107 bound variable or a constant then the let is unfolded.  Otherwise
  3108 first a is simplified to b, and then f b is simplified to g. If
  3109 possible we abstract b from g arriving at "let x = b in h x",
  3110 otherwise we unfold the let and arrive at g.  The simproc can be
  3111 enabled/disabled by the reference use_let_simproc.  Potential
  3112 INCOMPATIBILITY since simplification is more powerful by default.
  3113 
  3114 * Classical reasoning: the meson method now accepts theorems as arguments.
  3115 
  3116 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3117 jobs to provide advice on the provability of subgoals.
  3118 
  3119 * Theory OrderedGroup and Ring_and_Field: various additions and
  3120 improvements to faciliate calculations involving equalities and
  3121 inequalities.
  3122 
  3123 The following theorems have been eliminated or modified
  3124 (INCOMPATIBILITY):
  3125 
  3126   abs_eq             now named abs_of_nonneg
  3127   abs_of_ge_0        now named abs_of_nonneg
  3128   abs_minus_eq       now named abs_of_nonpos
  3129   imp_abs_id         now named abs_of_nonneg
  3130   imp_abs_neg_id     now named abs_of_nonpos
  3131   mult_pos           now named mult_pos_pos
  3132   mult_pos_le        now named mult_nonneg_nonneg
  3133   mult_pos_neg_le    now named mult_nonneg_nonpos
  3134   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3135   mult_neg           now named mult_neg_neg
  3136   mult_neg_le        now named mult_nonpos_nonpos
  3137 
  3138 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3139      
  3140      zero_le_square
  3141      not_square_less_zero 
  3142 
  3143   The following lemmas have been deleted from Real/RealPow:
  3144   
  3145      realpow_zero_zero
  3146      realpow_two
  3147      realpow_less
  3148      zero_le_power
  3149      realpow_two_le
  3150      abs_realpow_two
  3151      realpow_two_abs     
  3152 
  3153 * Theory Parity: added rules for simplifying exponents.
  3154 
  3155 * Theory List:
  3156 
  3157 The following theorems have been eliminated or modified
  3158 (INCOMPATIBILITY):
  3159 
  3160   list_all_Nil       now named list_all.simps(1)
  3161   list_all_Cons      now named list_all.simps(2)
  3162   list_all_conv      now named list_all_iff
  3163   set_mem_eq         now named mem_iff
  3164 
  3165 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3166 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3167 
  3168 
  3169 *** HOL-Complex ***
  3170 
  3171 * Theory RealDef: better support for embedding natural numbers and
  3172 integers in the reals.
  3173 
  3174 The following theorems have been eliminated or modified
  3175 (INCOMPATIBILITY):
  3176 
  3177   exp_ge_add_one_self  now requires no hypotheses
  3178   real_of_int_add      reversed direction of equality (use [symmetric])
  3179   real_of_int_minus    reversed direction of equality (use [symmetric])
  3180   real_of_int_diff     reversed direction of equality (use [symmetric])
  3181   real_of_int_mult     reversed direction of equality (use [symmetric])
  3182 
  3183 * Theory RComplete: expanded support for floor and ceiling functions.
  3184 
  3185 * Theory Ln is new, with properties of the natural logarithm
  3186 
  3187 * Hyperreal: There is a new type constructor "star" for making
  3188 nonstandard types.  The old type names are now type synonyms:
  3189 
  3190   hypreal = real star
  3191   hypnat = nat star
  3192   hcomplex = complex star
  3193 
  3194 * Hyperreal: Many groups of similarly-defined constants have been
  3195 replaced by polymorphic versions (INCOMPATIBILITY):
  3196 
  3197   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3198 
  3199   starset      <-- starsetNat, starsetC
  3200   *s*          <-- *sNat*, *sc*
  3201   starset_n    <-- starsetNat_n, starsetC_n
  3202   *sn*         <-- *sNatn*, *scn*
  3203   InternalSets <-- InternalNatSets, InternalCSets
  3204 
  3205   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3206   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3207   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3208   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3209   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3210 
  3211 * Hyperreal: Many type-specific theorems have been removed in favor of
  3212 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3213 
  3214   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3215   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3216   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3217   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3218   right_minus <-- hypreal_add_minus
  3219   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3220   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3221   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3222   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3223   mult_1_right <-- hcomplex_mult_one_right
  3224   mult_zero_left <-- hcomplex_mult_zero_left
  3225   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3226   right_distrib <-- hypnat_add_mult_distrib2
  3227   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3228   right_inverse <-- hypreal_mult_inverse
  3229   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3230   order_refl <-- {hypreal,hypnat}_le_refl
  3231   order_trans <-- {hypreal,hypnat}_le_trans
  3232   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3233   order_less_le <-- {hypreal,hypnat}_less_le
  3234   linorder_linear <-- {hypreal,hypnat}_le_linear
  3235   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3236   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3237   add_nonneg_nonneg <-- hypreal_le_add_order
  3238 
  3239 * Hyperreal: Separate theorems having to do with type-specific
  3240 versions of constants have been merged into theorems that apply to the
  3241 new polymorphic constants (INCOMPATIBILITY):
  3242 
  3243   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3244   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3245   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3246   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3247   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3248   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3249   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3250   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3251   STAR_diff <-- {STAR,STARC}_diff
  3252   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3253     STARC_hcomplex_of_complex}_image_subset
  3254   starset_n_Un <-- starset{Nat,C}_n_Un
  3255   starset_n_Int <-- starset{Nat,C}_n_Int
  3256   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3257   starset_n_diff <-- starset{Nat,C}_n_diff
  3258   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3259   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3260   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3261   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3262   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3263   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3264   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3265   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3266   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3267   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3268   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3269   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3270   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3271   starfun_diff <-- starfun{C,RC,CR}_diff
  3272   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3273   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3274   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3275   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3276   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3277   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3278   starfun_Id <-- starfunC_Id
  3279   starfun_approx <-- starfun{Nat,CR}_approx
  3280   starfun_capprox <-- starfun{C,RC}_capprox
  3281   starfun_abs <-- starfunNat_rabs
  3282   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3283   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3284   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3285   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3286   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3287   starfun_add_approx <-- starfunCR_add_approx
  3288   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3289   starfun_divide <-- starfun{C,CR,RC}_divide
  3290   starfun_n <-- starfun{Nat,C}_n
  3291   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3292   starfun_n_add <-- starfun{Nat,C}_n_add
  3293   starfun_n_add_minus <-- starfunNat_n_add_minus
  3294   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3295   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3296   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3297 
  3298   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3299   star_n_minus <-- {hypreal,hcomplex}_minus
  3300   star_n_diff <-- {hypreal,hcomplex}_diff
  3301   star_n_mult <-- {hypreal,hcomplex}_mult
  3302   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3303   star_n_le <-- {hypreal,hypnat}_le
  3304   star_n_less <-- {hypreal,hypnat}_less
  3305   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3306   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3307   star_n_abs <-- hypreal_hrabs
  3308   star_n_divide <-- hcomplex_divide
  3309 
  3310   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3311   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3312   star_of_diff <-- hypreal_of_real_diff
  3313   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3314   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3315   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3316   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3317   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3318   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3319   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3320   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3321   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3322   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3323   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3324   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3325   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3326   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3327   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3328   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3329   star_of_power <-- hypreal_of_real_power
  3330   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3331 
  3332 * Hyperreal: new method "transfer" that implements the transfer
  3333 principle of nonstandard analysis. With a subgoal that mentions
  3334 nonstandard types like "'a star", the command "apply transfer"
  3335 replaces it with an equivalent one that mentions only standard types.
  3336 To be successful, all free variables must have standard types; non-
  3337 standard variables must have explicit universal quantifiers.
  3338 
  3339 * Hyperreal: A theory of Taylor series.
  3340 
  3341 
  3342 *** HOLCF ***
  3343 
  3344 * Discontinued special version of 'constdefs' (which used to support
  3345 continuous functions) in favor of the general Pure one with full
  3346 type-inference.
  3347 
  3348 * New simplification procedure for solving continuity conditions; it
  3349 is much faster on terms with many nested lambda abstractions (cubic
  3350 instead of exponential time).
  3351 
  3352 * New syntax for domain package: selector names are now optional.
  3353 Parentheses should be omitted unless argument is lazy, for example:
  3354 
  3355   domain 'a stream = cons "'a" (lazy "'a stream")
  3356 
  3357 * New command 'fixrec' for defining recursive functions with pattern
  3358 matching; defining multiple functions with mutual recursion is also
  3359 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3360 sinr, or any data constructor defined by the domain package. The given
  3361 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3362 syntax and examples.
  3363 
  3364 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3365 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3366 but the proof obligation additionally includes an admissibility
  3367 requirement. The packages generate instances of class cpo or pcpo,
  3368 with continuity and strictness theorems for Rep and Abs.
  3369 
  3370 * HOLCF: Many theorems have been renamed according to a more standard naming
  3371 scheme (INCOMPATIBILITY):
  3372 
  3373   foo_inject:  "foo$x = foo$y ==> x = y"
  3374   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3375   foo_less:    "(foo$x << foo$y) = (x << y)"
  3376   foo_strict:  "foo$UU = UU"
  3377   foo_defined: "... ==> foo$x ~= UU"
  3378   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3379 
  3380 
  3381 *** ZF ***
  3382 
  3383 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3384 including the First Isomorphism Theorem (on quotienting by the kernel
  3385 of a homomorphism).
  3386 
  3387 * ZF/Simplifier: install second copy of type solver that actually
  3388 makes use of TC rules declared to Isar proof contexts (or locales);
  3389 the old version is still required for ML proof scripts.
  3390 
  3391 
  3392 *** Cube ***
  3393 
  3394 * Converted to Isar theory format; use locales instead of axiomatic
  3395 theories.
  3396 
  3397 
  3398 *** ML ***
  3399 
  3400 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3401 for ||>, ||>>, |>>,
  3402 
  3403 * Pure/library.ML no longer defines its own option datatype, but uses
  3404 that of the SML basis, which has constructors NONE and SOME instead of
  3405 None and Some, as well as exception Option.Option instead of OPTION.
  3406 The functions the, if_none, is_some, is_none have been adapted
  3407 accordingly, while Option.map replaces apsome.
  3408 
  3409 * Pure/library.ML: the exception LIST has been given up in favour of
  3410 the standard exceptions Empty and Subscript, as well as
  3411 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3412 superceded by the standard hd and tl functions etc.
  3413 
  3414 A number of basic list functions are no longer exported to the ML
  3415 toplevel, as they are variants of predefined functions.  The following
  3416 suggests how one can translate existing code:
  3417 
  3418     rev_append xs ys = List.revAppend (xs, ys)
  3419     nth_elem (i, xs) = List.nth (xs, i)
  3420     last_elem xs = List.last xs
  3421     flat xss = List.concat xss
  3422     seq fs = List.app fs
  3423     partition P xs = List.partition P xs
  3424     mapfilter f xs = List.mapPartial f xs
  3425 
  3426 * Pure/library.ML: several combinators for linear functional
  3427 transformations, notably reverse application and composition:
  3428 
  3429   x |> f                f #> g
  3430   (x, y) |-> f          f #-> g
  3431 
  3432 * Pure/library.ML: introduced/changed precedence of infix operators:
  3433 
  3434   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3435   infix 2 ?;
  3436   infix 3 o oo ooo oooo;
  3437   infix 4 ~~ upto downto;
  3438 
  3439 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3440 infix operators.
  3441 
  3442 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3443 fold_map support linear functional transformations and nesting.  For
  3444 example:
  3445 
  3446   fold f [x1, ..., xN] y =
  3447     y |> f x1 |> ... |> f xN
  3448 
  3449   (fold o fold) f [xs1, ..., xsN] y =
  3450     y |> fold f xs1 |> ... |> fold f xsN
  3451 
  3452   fold f [x1, ..., xN] =
  3453     f x1 #> ... #> f xN
  3454 
  3455   (fold o fold) f [xs1, ..., xsN] =
  3456     fold f xs1 #> ... #> fold f xsN
  3457 
  3458 * Pure/library.ML: the following selectors on type 'a option are
  3459 available:
  3460 
  3461   the:               'a option -> 'a  (*partial*)
  3462   these:             'a option -> 'a  where 'a = 'b list
  3463   the_default: 'a -> 'a option -> 'a
  3464   the_list:          'a option -> 'a list
  3465 
  3466 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3467 basic operations for association lists, following natural argument
  3468 order; moreover the explicit equality predicate passed here avoids
  3469 potentially expensive polymorphic runtime equality checks.
  3470 The old functions may be expressed as follows:
  3471 
  3472   assoc = uncurry (AList.lookup (op =))
  3473   assocs = these oo AList.lookup (op =)
  3474   overwrite = uncurry (AList.update (op =)) o swap
  3475 
  3476 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3477 
  3478   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3479   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3480 
  3481 replacing make_keylist and keyfilter (occassionally used)
  3482 Naive rewrites:
  3483 
  3484   make_keylist = AList.make
  3485   keyfilter = AList.find (op =)
  3486 
  3487 * eq_fst and eq_snd now take explicit equality parameter, thus
  3488   avoiding eqtypes. Naive rewrites:
  3489 
  3490     eq_fst = eq_fst (op =)
  3491     eq_snd = eq_snd (op =)
  3492 
  3493 * Removed deprecated apl and apr (rarely used).
  3494   Naive rewrites:
  3495 
  3496     apl (n, op) =>>= curry op n
  3497     apr (op, m) =>>= fn n => op (n, m)
  3498 
  3499 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3500 provides a reasonably efficient light-weight implementation of sets as
  3501 lists.
  3502 
  3503 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3504 few new operations; existing lookup and update are now curried to
  3505 follow natural argument order (for use with fold etc.);
  3506 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3507 
  3508 * Pure/General: output via the Isabelle channels of
  3509 writeln/warning/error etc. is now passed through Output.output, with a
  3510 hook for arbitrary transformations depending on the print_mode
  3511 (cf. Output.add_mode -- the first active mode that provides a output
  3512 function wins).  Already formatted output may be embedded into further
  3513 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3514 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3515 accommodate easy composition of diagnostic messages etc.  Programmers
  3516 rarely need to care about Output.output or Output.raw at all, with
  3517 some notable exceptions: Output.output is required when bypassing the
  3518 standard channels (writeln etc.), or in token translations to produce
  3519 properly formatted results; Output.raw is required when capturing
  3520 already output material that will eventually be presented to the user
  3521 a second time.  For the default print mode, both Output.output and
  3522 Output.raw have no effect.
  3523 
  3524 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3525 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3526 cumulative results are displayed at the end of a batch session.
  3527 
  3528 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3529 replaced by File.platform_path and File.shell_path (with appropriate
  3530 hooks).  This provides a clean interface for unusual systems where the
  3531 internal and external process view of file names are different.
  3532 
  3533 * Pure: more efficient orders for basic syntactic entities: added
  3534 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3535 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3536 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3537 orders now -- potential INCOMPATIBILITY for code that depends on a
  3538 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3539 Library.sort_strings on result).
  3540 
  3541 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3542 fold_types traverse types/terms from left to right, observing natural
  3543 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3544 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3545 
  3546 * Pure: name spaces have been refined, with significant changes of the
  3547 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3548 to extern(_table).  The plain name entry path is superceded by a
  3549 general 'naming' context, which also includes the 'policy' to produce
  3550 a fully qualified name and external accesses of a fully qualified
  3551 name; NameSpace.extend is superceded by context dependent
  3552 Sign.declare_name.  Several theory and proof context operations modify
  3553 the naming context.  Especially note Theory.restore_naming and
  3554 ProofContext.restore_naming to get back to a sane state; note that
  3555 Theory.add_path is no longer sufficient to recover from
  3556 Theory.absolute_path in particular.
  3557 
  3558 * Pure: new flags short_names (default false) and unique_names
  3559 (default true) for controlling output of qualified names.  If
  3560 short_names is set, names are printed unqualified.  If unique_names is
  3561 reset, the name prefix is reduced to the minimum required to achieve
  3562 the original result when interning again, even if there is an overlap
  3563 with earlier declarations.
  3564 
  3565 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3566 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3567 (useful for printing error messages).  INCOMPATIBILITY.
  3568 
  3569 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3570 Theory.theory are now identified, referring to the universal
  3571 Context.theory (see Pure/context.ML).  Actual signature and theory
  3572 content is managed as theory data.  The old code and interfaces were
  3573 spread over many files and structures; the new arrangement introduces
  3574 considerable INCOMPATIBILITY to gain more clarity:
  3575 
  3576   Context -- theory management operations (name, identity, inclusion,
  3577     parents, ancestors, merge, etc.), plus generic theory data;
  3578 
  3579   Sign -- logical signature and syntax operations (declaring consts,
  3580     types, etc.), plus certify/read for common entities;
  3581 
  3582   Theory -- logical theory operations (stating axioms, definitions,
  3583     oracles), plus a copy of logical signature operations (consts,
  3584     types, etc.); also a few basic management operations (Theory.copy,
  3585     Theory.merge, etc.)
  3586 
  3587 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3588 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3589 for convenience -- they merely return the theory.
  3590 
  3591 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3592 
  3593 * Pure: the Isar proof context type is already defined early in Pure
  3594 as Context.proof (note that ProofContext.context and Proof.context are
  3595 aliases, where the latter is the preferred name).  This enables other
  3596 Isabelle components to refer to that type even before Isar is present.
  3597 
  3598 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3599 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3600 any of these kinds.  For example, Sign.intern typeK is now
  3601 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3602 Theory.hide_types.  Also note that former
  3603 Theory.hide_classes/types/consts are now
  3604 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3605 internalize their arguments!  INCOMPATIBILITY.
  3606 
  3607 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3608 datatype thmref (with constructors Name and NameSelection) instead of
  3609 plain string -- INCOMPATIBILITY;
  3610 
  3611 * Pure: cases produced by proof methods specify options, where NONE
  3612 means to remove case bindings -- INCOMPATIBILITY in
  3613 (RAW_)METHOD_CASES.
  3614 
  3615 * Pure: the following operations retrieve axioms or theorems from a
  3616 theory node or theory hierarchy, respectively:
  3617 
  3618   Theory.axioms_of: theory -> (string * term) list
  3619   Theory.all_axioms_of: theory -> (string * term) list
  3620   PureThy.thms_of: theory -> (string * thm) list
  3621   PureThy.all_thms_of: theory -> (string * thm) list
  3622 
  3623 * Pure: print_tac now outputs the goal through the trace channel.
  3624 
  3625 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3626 Reference Toplevel.debug (default false) controls detailed printing
  3627 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3628 controls execution profiling -- set to 1 for time and 2 for space
  3629 (both increase the runtime).
  3630 
  3631 * Isar session: The initial use of ROOT.ML is now always timed,
  3632 i.e. the log will show the actual process times, in contrast to the
  3633 elapsed wall-clock time that the outer shell wrapper produces.
  3634 
  3635 * Simplifier: improved handling of bound variables (nameless
  3636 representation, avoid allocating new strings).  Simprocs that invoke
  3637 the Simplifier recursively should use Simplifier.inherit_bounds to
  3638 avoid local name clashes.  Failure to do so produces warnings
  3639 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3640 for further details.
  3641 
  3642 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3643 bindings for all theorems stored within a given theory; this may help
  3644 in porting non-Isar theories to Isar ones, while keeping ML proof
  3645 scripts for the time being.
  3646 
  3647 * ML operator HTML.with_charset specifies the charset begin used for
  3648 generated HTML files.  For example:
  3649 
  3650   HTML.with_charset "utf-8" use_thy "Hebrew";
  3651   HTML.with_charset "utf-8" use_thy "Chinese";
  3652 
  3653 
  3654 *** System ***
  3655 
  3656 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3657 isabelle, isatool etc.).
  3658 
  3659 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3660 isatool doc, isatool mkdir, display_drafts etc.).
  3661 
  3662 * isatool usedir: option -f allows specification of the ML file to be
  3663 used by Isabelle; default is ROOT.ML.
  3664 
  3665 * New isatool version outputs the version identifier of the Isabelle
  3666 distribution being used.
  3667 
  3668 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3669 (containing Boolean satisfiability problems) into Isabelle/HOL
  3670 theories.
  3671 
  3672 
  3673 
  3674 New in Isabelle2004 (April 2004)
  3675 --------------------------------
  3676 
  3677 *** General ***
  3678 
  3679 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3680   Replaces linorder.ML.
  3681 
  3682 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3683   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3684   (\<a>...\<z>), are now considered normal letters, and can therefore
  3685   be used anywhere where an ASCII letter (a...zA...Z) has until
  3686   now. COMPATIBILITY: This obviously changes the parsing of some
  3687   terms, especially where a symbol has been used as a binder, say
  3688   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3689   as an identifier.  Fix it by inserting a space around former
  3690   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3691   existing theory and ML files.
  3692 
  3693 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3694 
  3695 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3696   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3697   a normal (but invisible) letter. For multiple letter subscripts repeat
  3698   \<^isub> like this: x\<^isub>1\<^isub>2.
  3699 
  3700 * Pure: There are now sub-/superscripts that can span more than one
  3701   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3702   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3703   superscript. The new control characters are not identifier parts.
  3704 
  3705 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3706   content of "..." to the latex file instead of \isacntrl... . The "..."
  3707   may consist of any printable characters excluding the end bracket >.
  3708 
  3709 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3710   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3711   declare constants "final", which prevents their being given a definition
  3712   later.  It is useful for constants whose behaviour is fixed axiomatically
  3713   rather than definitionally, such as the meta-logic connectives.
  3714 
  3715 * Pure: 'instance' now handles general arities with general sorts
  3716   (i.e. intersections of classes),
  3717 
  3718 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3719   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3720   It can be changed to alter the colors/layout of generated pages.
  3721 
  3722 
  3723 *** Isar ***
  3724 
  3725 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3726   cut_tac, subgoal_tac and thin_tac:
  3727   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3728     locales are no longer forced to write Isar proof scripts.
  3729     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3730     emulations.
  3731   - INCOMPATIBILITY: names of variables to be instantiated may no
  3732     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3733     This is consistent with the instantiation attribute "where".
  3734 
  3735 * Attributes "where" and "of":
  3736   - Now take type variables of instantiated theorem into account when reading
  3737     the instantiation string.  This fixes a bug that caused instantiated
  3738     theorems to have too special types in some circumstances.
  3739   - "where" permits explicit instantiations of type variables.
  3740 
  3741 * Calculation commands "moreover" and "also" no longer interfere with
  3742   current facts ("this"), admitting arbitrary combinations with "then"
  3743   and derived forms.
  3744 
  3745 * Locales:
  3746   - Goal statements involving the context element "includes" no longer
  3747     generate theorems with internal delta predicates (those ending on
  3748     "_axioms") in the premise.
  3749     Resolve particular premise with <locale>.intro to obtain old form.
  3750   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3751     specification and "includes" elements in goal statement.
  3752   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3753     [intro?] and [elim?] (respectively) by default.
  3754   - Experimental command for instantiation of locales in proof contexts:
  3755         instantiate <label>[<attrs>]: <loc>
  3756     Instantiates locale <loc> and adds all its theorems to the current context
  3757     taking into account their attributes.  Label and attrs are optional
  3758     modifiers, like in theorem declarations.  If present, names of
  3759     instantiated theorems are qualified with <label>, and the attributes
  3760     <attrs> are applied after any attributes these theorems might have already.
  3761       If the locale has assumptions, a chained fact of the form
  3762     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3763     are derived.  The command does not support old-style locales declared
  3764     with "locale (open)".
  3765       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3766 
  3767 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3768   (Isar) contexts.
  3769 
  3770 
  3771 *** HOL ***
  3772 
  3773 * Proof import: new image HOL4 contains the imported library from
  3774   the HOL4 system with about 2500 theorems. It is imported by
  3775   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3776   can be used like any other Isabelle image.  See
  3777   HOL/Import/HOL/README for more information.
  3778 
  3779 * Simplifier:
  3780   - Much improved handling of linear and partial orders.
  3781     Reasoners for linear and partial orders are set up for type classes
  3782     "linorder" and "order" respectively, and are added to the default simpset
  3783     as solvers.  This means that the simplifier can build transitivity chains
  3784     to solve goals from the assumptions.
  3785   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3786     of blast or auto after simplification become unnecessary because the goal
  3787     is solved by simplification already.
  3788 
  3789 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3790     all proved in axiomatic type classes for semirings, rings and fields.
  3791 
  3792 * Numerics:
  3793   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3794     now formalized using the Ring_and_Field theory mentioned above.
  3795   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3796     than before, because now they are set up once in a generic manner.
  3797   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3798     Look for the general versions in Ring_and_Field (and Power if they concern
  3799     exponentiation).
  3800 
  3801 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3802 
  3803 * Records:
  3804   - Record types are now by default printed with their type abbreviation
  3805     instead of the list of all field types. This can be configured via
  3806     the reference "print_record_type_abbr".
  3807   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3808     (not enabled by default).
  3809   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3810     EX x. x = sel r to True (not enabled by default).
  3811   - Tactic "record_split_simp_tac" to split and simplify records added.
  3812 
  3813 * 'specification' command added, allowing for definition by
  3814   specification.  There is also an 'ax_specification' command that
  3815   introduces the new constants axiomatically.
  3816 
  3817 * arith(_tac) is now able to generate counterexamples for reals as well.
  3818 
  3819 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3820 
  3821 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3822   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3823 
  3824 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3825   matrix theory to linear programming.
  3826 
  3827 * Unions and Intersections:
  3828   The latex output syntax of UN and INT has been changed
  3829   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3830   i.e. the index formulae has become a subscript.
  3831   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3832 
  3833 * Unions and Intersections over Intervals:
  3834   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3835   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3836   like in normal math, and corresponding versions for < and for intersection.
  3837 
  3838 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3839   lexicographic dictonary ordering has been added as "lexord".
  3840 
  3841 * ML: the legacy theory structures Int and List have been removed. They had
  3842   conflicted with ML Basis Library structures having the same names.
  3843 
  3844 * 'refute' command added to search for (finite) countermodels.  Only works
  3845   for a fragment of HOL.  The installation of an external SAT solver is
  3846   highly recommended.  See "HOL/Refute.thy" for details.
  3847 
  3848 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3849   formulae under an assignment of free variables to random values.
  3850   In contrast to 'refute', it can deal with inductive datatypes,
  3851   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3852   for examples.
  3853 
  3854 
  3855 *** HOLCF ***
  3856 
  3857 * Streams now come with concatenation and are part of the HOLCF image
  3858 
  3859 
  3860 
  3861 New in Isabelle2003 (May 2003)
  3862 ------------------------------
  3863 
  3864 *** General ***
  3865 
  3866 * Provers/simplifier:
  3867 
  3868   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3869     Assumptions are now subject to complete mutual simplification,
  3870     not just from left to right. The simplifier now preserves
  3871     the order of assumptions.
  3872 
  3873     Potential INCOMPATIBILITY:
  3874 
  3875     -- simp sometimes diverges where the old version did
  3876        not, e.g. invoking simp on the goal
  3877 
  3878         [| P (f x); y = x; f x = f y |] ==> Q
  3879 
  3880        now gives rise to the infinite reduction sequence
  3881 
  3882         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3883 
  3884        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3885        kind of problem.
  3886 
  3887     -- Tactics combining classical reasoner and simplification (such as auto)
  3888        are also affected by this change, because many of them rely on
  3889        simp. They may sometimes diverge as well or yield a different numbers
  3890        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3891        in case of problems. Sometimes subsequent calls to the classical
  3892        reasoner will fail because a preceeding call to the simplifier too
  3893        eagerly simplified the goal, e.g. deleted redundant premises.
  3894 
  3895   - The simplifier trace now shows the names of the applied rewrite rules
  3896 
  3897   - You can limit the number of recursive invocations of the simplifier
  3898     during conditional rewriting (where the simplifie tries to solve the
  3899     conditions before applying the rewrite rule):
  3900     ML "simp_depth_limit := n"
  3901     where n is an integer. Thus you can force termination where previously
  3902     the simplifier would diverge.
  3903 
  3904   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3905 
  3906   - No longer aborts on failed congruence proof.  Instead, the
  3907     congruence is ignored.
  3908 
  3909 * Pure: New generic framework for extracting programs from constructive
  3910   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3911   as HOL/Extraction for some case studies.
  3912 
  3913 * Pure: The main goal of the proof state is no longer shown by default, only
  3914 the subgoals. This behaviour is controlled by a new flag.
  3915    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3916 (ML: Proof.show_main_goal).
  3917 
  3918 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3919 rules whose conclusion matches subgoal 1:
  3920       PG menu: Isabelle/Isar -> Show me -> matching rules
  3921 The rules are ordered by how closely they match the subgoal.
  3922 In particular, rules that solve a subgoal outright are displayed first
  3923 (or rather last, the way they are printed).
  3924 (ML: ProofGeneral.print_intros())
  3925 
  3926 * Pure: New flag trace_unify_fail causes unification to print
  3927 diagnostic information (PG: in trace buffer) when it fails. This is
  3928 useful for figuring out why single step proofs like rule, erule or
  3929 assumption failed.
  3930 
  3931 * Pure: Locale specifications now produce predicate definitions
  3932 according to the body of text (covering assumptions modulo local
  3933 definitions); predicate "loc_axioms" covers newly introduced text,
  3934 while "loc" is cumulative wrt. all included locale expressions; the
  3935 latter view is presented only on export into the global theory
  3936 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3937 on the old view without predicates;
  3938 
  3939 * Pure: predefined locales "var" and "struct" are useful for sharing
  3940 parameters (as in CASL, for example); just specify something like
  3941 ``var x + var y + struct M'' as import;
  3942 
  3943 * Pure: improved thms_containing: proper indexing of facts instead of
  3944 raw theorems; check validity of results wrt. current name space;
  3945 include local facts of proof configuration (also covers active
  3946 locales), cover fixed variables in index; may use "_" in term
  3947 specification; an optional limit for the number of printed facts may
  3948 be given (the default is 40);
  3949 
  3950 * Pure: disallow duplicate fact bindings within new-style theory files
  3951 (batch-mode only);
  3952 
  3953 * Provers: improved induct method: assumptions introduced by case
  3954 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3955 the goal statement); "foo" still refers to all facts collectively;
  3956 
  3957 * Provers: the function blast.overloaded has been removed: all constants
  3958 are regarded as potentially overloaded, which improves robustness in exchange
  3959 for slight decrease in efficiency;
  3960 
  3961 * Provers/linorder: New generic prover for transitivity reasoning over
  3962 linear orders.  Note: this prover is not efficient!
  3963 
  3964 * Isar: preview of problems to finish 'show' now produce an error
  3965 rather than just a warning (in interactive mode);
  3966 
  3967 
  3968 *** HOL ***
  3969 
  3970 * arith(_tac)
  3971 
  3972  - Produces a counter example if it cannot prove a goal.
  3973    Note that the counter example may be spurious if the goal is not a formula
  3974    of quantifier-free linear arithmetic.
  3975    In ProofGeneral the counter example appears in the trace buffer.
  3976 
  3977  - Knows about div k and mod k where k is a numeral of type nat or int.
  3978 
  3979  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3980    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3981    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3982 
  3983 * simp's arithmetic capabilities have been enhanced a bit: it now
  3984 takes ~= in premises into account (by performing a case split);
  3985 
  3986 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3987 are distributed over a sum of terms;
  3988 
  3989 * New tactic "trans_tac" and method "trans" instantiate
  3990 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3991 "<=", "<" and "=").
  3992 
  3993 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3994 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3995 
  3996 * 'typedef' command has new option "open" to suppress the set
  3997 definition;
  3998 
  3999 * functions Min and Max on finite sets have been introduced (theory
  4000 Finite_Set);
  4001 
  4002 * attribute [symmetric] now works for relations as well; it turns
  4003 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4004 
  4005 * induct over a !!-quantified statement (say !!x1..xn):
  4006   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4007 
  4008 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4009 %x. None. Warning: empty_def now refers to the previously hidden definition
  4010 of the empty set.
  4011 
  4012 * Algebra: formalization of classical algebra.  Intended as base for
  4013 any algebraic development in Isabelle.  Currently covers group theory
  4014 (up to Sylow's theorem) and ring theory (Universal Property of
  4015 Univariate Polynomials).  Contributions welcome;
  4016 
  4017 * GroupTheory: deleted, since its material has been moved to Algebra;
  4018 
  4019 * Complex: new directory of the complex numbers with numeric constants,
  4020 nonstandard complex numbers, and some complex analysis, standard and
  4021 nonstandard (Jacques Fleuriot);
  4022 
  4023 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4024 
  4025 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4026 Fleuriot);
  4027 
  4028 * Real/HahnBanach: updated and adapted to locales;
  4029 
  4030 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4031 Gray and Kramer);
  4032 
  4033 * UNITY: added the Meier-Sanders theory of progress sets;
  4034 
  4035 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4036 as abstract algorithms, instantiated to the JVM;
  4037 
  4038 * Bali: Java source language formalization. Type system, operational
  4039 semantics, axiomatic semantics. Supported language features:
  4040 classes, interfaces, objects,virtual methods, static methods,
  4041 static/instance fields, arrays, access modifiers, definite
  4042 assignment, exceptions.
  4043 
  4044 
  4045 *** ZF ***
  4046 
  4047 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4048 universe, etc.);
  4049 
  4050 * Main ZF: virtually all theories converted to new-style format;
  4051 
  4052 
  4053 *** ML ***
  4054 
  4055 * Pure: Tactic.prove provides sane interface for internal proofs;
  4056 omits the infamous "standard" operation, so this is more appropriate
  4057 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4058 
  4059 * Pure: improved error reporting of simprocs;
  4060 
  4061 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4062 up simprocs;
  4063 
  4064 
  4065 *** Document preparation ***
  4066 
  4067 * uses \par instead of \\ for line breaks in theory text. This may
  4068 shift some page breaks in large documents. To get the old behaviour
  4069 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4070 
  4071 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4072 other packages
  4073 
  4074 * \<euro> now needs package babel/greek instead of marvosym (which
  4075 broke \Rightarrow)
  4076 
  4077 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4078 textcomp package)
  4079 
  4080 
  4081 
  4082 New in Isabelle2002 (March 2002)
  4083 --------------------------------
  4084 
  4085 *** Document preparation ***
  4086 
  4087 * greatly simplified document preparation setup, including more
  4088 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4089 instructive isatool mkdir; users should basically be able to get
  4090 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4091 users may run a separate document processing stage manually like this:
  4092 "isatool usedir -D output HOL Test && isatool document Test/output";
  4093 
  4094 * theory dependency graph may now be incorporated into documents;
  4095 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4096 with \includegraphics of LaTeX;
  4097 
  4098 * proper spacing of consecutive markup elements, especially text
  4099 blocks after section headings;
  4100 
  4101 * support bold style (for single symbols only), input syntax is like
  4102 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4103 
  4104 * \<bullet> is now output as bold \cdot by default, which looks much
  4105 better in printed text;
  4106 
  4107 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4108 note that these symbols are currently unavailable in Proof General /
  4109 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4110 
  4111 * isatool latex no longer depends on changed TEXINPUTS, instead
  4112 isatool document copies the Isabelle style files to the target
  4113 location;
  4114 
  4115 
  4116 *** Isar ***
  4117 
  4118 * Pure/Provers: improved proof by cases and induction;
  4119   - 'case' command admits impromptu naming of parameters (such as
  4120     "case (Suc n)");
  4121   - 'induct' method divinates rule instantiation from the inductive
  4122     claim; no longer requires excessive ?P bindings for proper
  4123     instantiation of cases;
  4124   - 'induct' method properly enumerates all possibilities of set/type
  4125     rules; as a consequence facts may be also passed through *type*
  4126     rules without further ado;
  4127   - 'induct' method now derives symbolic cases from the *rulified*
  4128     rule (before it used to rulify cases stemming from the internal
  4129     atomized version); this means that the context of a non-atomic
  4130     statement becomes is included in the hypothesis, avoiding the
  4131     slightly cumbersome show "PROP ?case" form;
  4132   - 'induct' may now use elim-style induction rules without chaining
  4133     facts, using ``missing'' premises from the goal state; this allows
  4134     rules stemming from inductive sets to be applied in unstructured
  4135     scripts, while still benefitting from proper handling of non-atomic
  4136     statements; NB: major inductive premises need to be put first, all
  4137     the rest of the goal is passed through the induction;
  4138   - 'induct' proper support for mutual induction involving non-atomic
  4139     rule statements (uses the new concept of simultaneous goals, see
  4140     below);
  4141   - append all possible rule selections, but only use the first
  4142     success (no backtracking);
  4143   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4144   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4145   - added 'print_induct_rules' (covered by help item in recent Proof
  4146     General versions);
  4147   - moved induct/cases attributes to Pure, methods to Provers;
  4148   - generic method setup instantiated for FOL and HOL;
  4149 
  4150 * Pure: support multiple simultaneous goal statements, for example
  4151 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4152 meta-level mechanism, this acts as if several individual goals had
  4153 been stated separately; in particular common proof methods need to be
  4154 repeated in order to cover all claims; note that a single elimination
  4155 step is *not* sufficient to establish the two conjunctions, so this
  4156 fails:
  4157 
  4158   assume "A & B" then have A and B ..   (*".." fails*)
  4159 
  4160 better use "obtain" in situations as above; alternative refer to
  4161 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4162 
  4163 * Pure: proper integration with ``locales''; unlike the original
  4164 version by Florian Kammller, Isar locales package high-level proof
  4165 contexts rather than raw logical ones (e.g. we admit to include
  4166 attributes everywhere); operations on locales include merge and
  4167 rename; support for implicit arguments (``structures''); simultaneous
  4168 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4169 some examples;
  4170 
  4171 * Pure: the following commands have been ``localized'', supporting a
  4172 target locale specification "(in name)": 'lemma', 'theorem',
  4173 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4174 stored both within the locale and at the theory level (exported and
  4175 qualified by the locale name);
  4176 
  4177 * Pure: theory goals may now be specified in ``long'' form, with
  4178 ad-hoc contexts consisting of arbitrary locale elements. for example
  4179 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4180 definitions may be given, too); the result is a meta-level rule with
  4181 the context elements being discharged in the obvious way;
  4182 
  4183 * Pure: new proof command 'using' allows to augment currently used
  4184 facts after a goal statement ('using' is syntactically analogous to
  4185 'apply', but acts on the goal's facts only); this allows chained facts
  4186 to be separated into parts given before and after a claim, as in
  4187 ``from a and b have C using d and e <proof>'';
  4188 
  4189 * Pure: renamed "antecedent" case to "rule_context";
  4190 
  4191 * Pure: new 'judgment' command records explicit information about the
  4192 object-logic embedding (used by several tools internally); no longer
  4193 use hard-wired "Trueprop";
  4194 
  4195 * Pure: added 'corollary' command;
  4196 
  4197 * Pure: fixed 'token_translation' command;
  4198 
  4199 * Pure: removed obsolete 'exported' attribute;
  4200 
  4201 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4202 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4203 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4204 
  4205 * Pure: method 'atomize' presents local goal premises as object-level
  4206 statements (atomic meta-level propositions); setup controlled via
  4207 rewrite rules declarations of 'atomize' attribute; example
  4208 application: 'induct' method with proper rule statements in improper
  4209 proof *scripts*;
  4210 
  4211 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4212 now consider the syntactic context of assumptions, giving a better
  4213 chance to get type-inference of the arguments right (this is
  4214 especially important for locales);
  4215 
  4216 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4217 mode;
  4218 
  4219 * Pure/obtain: the formal conclusion "thesis", being marked as
  4220 ``internal'', may no longer be reference directly in the text;
  4221 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4222 situations;
  4223 
  4224 * Pure: generic 'sym' attribute which declares a rule both as pure
  4225 'elim?' and for the 'symmetric' operation;
  4226 
  4227 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4228 text; the fixed correlation with particular command syntax has been
  4229 discontinued;
  4230 
  4231 * Pure: new method 'rules' is particularly well-suited for proof
  4232 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4233 but often produces more compact proof terms with less detours;
  4234 
  4235 * Pure/Provers/classical: simplified integration with pure rule
  4236 attributes and methods; the classical "intro?/elim?/dest?"
  4237 declarations coincide with the pure ones; the "rule" method no longer
  4238 includes classically swapped intros; "intro" and "elim" methods no
  4239 longer pick rules from the context; also got rid of ML declarations
  4240 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4241 INCOMPATIBILITY;
  4242 
  4243 * Provers/classical: attribute 'swapped' produces classical inversions
  4244 of introduction rules;
  4245 
  4246 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4247 rules instead of full simplifier context; 'iff' attribute handles
  4248 conditional rules;
  4249 
  4250 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4251 
  4252 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4253 "(permissive)" option to recover old behavior;
  4254 
  4255 * HOL: 'inductive' no longer features separate (collective) attributes
  4256 for 'intros' (was found too confusing);
  4257 
  4258 * HOL: properly declared induction rules less_induct and
  4259 wf_induct_rule;
  4260 
  4261 
  4262 *** HOL ***
  4263 
  4264 * HOL: moved over to sane numeral syntax; the new policy is as
  4265 follows:
  4266 
  4267   - 0 and 1 are polymorphic constants, which are defined on any
  4268   numeric type (nat, int, real etc.);
  4269 
  4270   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4271   binary representation internally;
  4272 
  4273   - type nat has special constructor Suc, and generally prefers Suc 0
  4274   over 1::nat and Suc (Suc 0) over 2::nat;
  4275 
  4276 This change may cause significant problems of INCOMPATIBILITY; here
  4277 are some hints on converting existing sources:
  4278 
  4279   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4280   entities, so expressions involving "-" (unary or binary minus) need
  4281   to be spaced properly;
  4282 
  4283   - existing occurrences of "1" may need to be constraint "1::nat" or
  4284   even replaced by Suc 0; similar for old "2";
  4285 
  4286   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4287 
  4288   - remove all special provisions on numerals in proofs;
  4289 
  4290 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4291 representation (depends on bin_arith_simps in the default context);
  4292 
  4293 * HOL: symbolic syntax for x^2 (numeral 2);
  4294 
  4295 * HOL: the class of all HOL types is now called "type" rather than
  4296 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4297 in axclass/classes, instance/arities, and (usually rare) occurrences
  4298 in typings (of consts etc.); internally the class is called
  4299 "HOL.type", ML programs should refer to HOLogic.typeS;
  4300 
  4301 * HOL/record package improvements:
  4302   - new derived operations "fields" to build a partial record section,
  4303     "extend" to promote a fixed record to a record scheme, and
  4304     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4305     declared as simp by default;
  4306   - shared operations ("more", "fields", etc.) now need to be always
  4307     qualified) --- potential INCOMPATIBILITY;
  4308   - removed "make_scheme" operations (use "make" with "extend") --
  4309     INCOMPATIBILITY;
  4310   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4311   - provides cases/induct rules for use with corresponding Isar
  4312     methods (for concrete records, record schemes, concrete more
  4313     parts, and schematic more parts -- in that order);
  4314   - internal definitions directly based on a light-weight abstract
  4315     theory of product types over typedef rather than datatype;
  4316 
  4317 * HOL: generic code generator for generating executable ML code from
  4318 specifications; specific support for HOL constructs such as inductive
  4319 datatypes and sets, as well as recursive functions; can be invoked
  4320 via 'generate_code' theory section;
  4321 
  4322 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4323 
  4324 * HOL: consolidated and renamed several theories.  In particular:
  4325         Ord.thy has been absorbed into HOL.thy
  4326         String.thy has been absorbed into List.thy
  4327 
  4328 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4329 (beware of argument permutation!);
  4330 
  4331 * HOL: linorder_less_split superseded by linorder_cases;
  4332 
  4333 * HOL/List: "nodups" renamed to "distinct";
  4334 
  4335 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4336 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4337   - Ex_def has changed, now need to use some_eq_ex
  4338 
  4339 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4340 in this (rare) case use:
  4341 
  4342   delSWrapper "split_all_tac"
  4343   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4344 
  4345 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4346 MAY FAIL;
  4347 
  4348 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4349 Isabelle's type classes, ^ on functions and relations has too general
  4350 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4351 necessary to attach explicit type constraints;
  4352 
  4353 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4354 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4355 renamed accordingly (eg "compI" -> "rel_compI").
  4356 
  4357 * HOL: syntax translations now work properly with numerals and records
  4358 expressions;
  4359 
  4360 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4361 of "lam" -- INCOMPATIBILITY;
  4362 
  4363 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4364 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4365 renamed "Product_Type.unit";
  4366 
  4367 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4368 
  4369 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4370 the "cases" method);
  4371 
  4372 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4373 Florian Kammller);
  4374 
  4375 * HOL/IMP: updated and converted to new-style theory format; several
  4376 parts turned into readable document, with proper Isar proof texts and
  4377 some explanations (by Gerwin Klein);
  4378 
  4379 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4380 
  4381 * HOL-Hyperreal is now a logic image;
  4382 
  4383 
  4384 *** HOLCF ***
  4385 
  4386 * Isar: consts/constdefs supports mixfix syntax for continuous
  4387 operations;
  4388 
  4389 * Isar: domain package adapted to new-style theory format, e.g. see
  4390 HOLCF/ex/Dnat.thy;
  4391 
  4392 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4393 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4394 lift.induct_tac, always use UU instead of Undef;
  4395 
  4396 * HOLCF/IMP: updated and converted to new-style theory;
  4397 
  4398 
  4399 *** ZF ***
  4400 
  4401 * Isar: proper integration of logic-specific tools and packages,
  4402 including theory commands '(co)inductive', '(co)datatype',
  4403 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4404 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4405 
  4406 * theory Main no longer includes AC; for the Axiom of Choice, base
  4407 your theory on Main_ZFC;
  4408 
  4409 * the integer library now covers quotients and remainders, with many
  4410 laws relating division to addition, multiplication, etc.;
  4411 
  4412 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4413 typeless version of the formalism;
  4414 
  4415 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4416 format;
  4417 
  4418 * ZF/Induct: new directory for examples of inductive definitions,
  4419 including theory Multiset for multiset orderings; converted to
  4420 new-style theory format;
  4421 
  4422 * ZF: many new theorems about lists, ordinals, etc.;
  4423 
  4424 
  4425 *** General ***
  4426 
  4427 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4428 variable proof controls level of detail: 0 = no proofs (only oracle
  4429 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4430 also ref manual for further ML interfaces;
  4431 
  4432 * Pure/axclass: removed obsolete ML interface
  4433 goal_subclass/goal_arity;
  4434 
  4435 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4436 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4437 separate tokens, so expressions involving minus need to be spaced
  4438 properly;
  4439 
  4440 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4441 rather than "infixl" or "infixr";
  4442 
  4443 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4444 sort constraint specifications in type inference; e.g. "x::_::foo"
  4445 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4446 type variable);
  4447 
  4448 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4449 control output of nested => (types); the default behavior is
  4450 "type_brackets";
  4451 
  4452 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4453 tokens into AST constants;
  4454 
  4455 * Pure/syntax: prefer later declarations of translations and print
  4456 translation functions; potential INCOMPATIBILITY: need to reverse
  4457 multiple declarations for same syntax element constant;
  4458 
  4459 * Pure/show_hyps reset by default (in accordance to existing Isar
  4460 practice);
  4461 
  4462 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4463 addSafter;
  4464 
  4465 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4466 as well;
  4467 
  4468 * system: tested support for MacOS X; should be able to get Isabelle +
  4469 Proof General to work in a plain Terminal after installing Poly/ML
  4470 (e.g. from the Isabelle distribution area) and GNU bash alone
  4471 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4472 support requires further installations, e.g. from
  4473 http://fink.sourceforge.net/);
  4474 
  4475 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4476 
  4477 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4478 of 40 MB), cf. ML_OPTIONS;
  4479 
  4480 * system: Proof General keywords specification is now part of the
  4481 Isabelle distribution (see etc/isar-keywords.el);
  4482 
  4483 * system: support for persistent Proof General sessions (refrain from
  4484 outdating all loaded theories on startup); user may create writable
  4485 logic images like this: ``isabelle -q HOL Test'';
  4486 
  4487 * system: smart selection of Isabelle process versus Isabelle
  4488 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4489 run both "isabelle" and "Isabelle" even if file names are badly
  4490 damaged (executable inspects the case of the first letter of its own
  4491 name); added separate "isabelle-process" and "isabelle-interface";
  4492 
  4493 * system: refrain from any attempt at filtering input streams; no
  4494 longer support ``8bit'' encoding of old isabelle font, instead proper
  4495 iso-latin characters may now be used; the related isatools
  4496 "symbolinput" and "nonascii" have disappeared as well;
  4497 
  4498 * system: removed old "xterm" interface (the print modes "xterm" and
  4499 "xterm_color" are still available for direct use in a suitable
  4500 terminal);
  4501 
  4502 
  4503 
  4504 New in Isabelle99-2 (February 2001)
  4505 -----------------------------------
  4506 
  4507 *** Overview of INCOMPATIBILITIES ***
  4508 
  4509 * HOL: please note that theories in the Library and elsewhere often use the
  4510 new-style (Isar) format; to refer to their theorems in an ML script you must
  4511 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4512 
  4513 * HOL: inductive package no longer splits induction rule aggressively,
  4514 but only as far as specified by the introductions given; the old
  4515 format may be recovered via ML function complete_split_rule or attribute
  4516 'split_rule (complete)';
  4517 
  4518 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4519 gfp_Tarski to gfp_unfold;
  4520 
  4521 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4522 
  4523 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4524 relation); infix "^^" has been renamed "``"; infix "``" has been
  4525 renamed "`"; "univalent" has been renamed "single_valued";
  4526 
  4527 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4528 operation;
  4529 
  4530 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4531 
  4532 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4533 
  4534 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4535 consequence, it is no longer monotonic wrt. the local goal context
  4536 (which is now passed through the inductive cases);
  4537 
  4538 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4539 \<gg> to \<ggreater>;
  4540 
  4541 
  4542 *** Document preparation ***
  4543 
  4544 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4545 available: are "it" for near math-mode best-style output, "sl" for
  4546 slanted text style, and "tt" for plain type-writer; if no
  4547 \isabellestyle command is given, output is according to slanted
  4548 type-writer);
  4549 
  4550 * support sub/super scripts (for single symbols only), input syntax is
  4551 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4552 
  4553 * some more standard symbols; see Appendix A of the system manual for
  4554 the complete list of symbols defined in isabellesym.sty;
  4555 
  4556 * improved isabelle style files; more abstract symbol implementation
  4557 (should now use \isamath{...} and \isatext{...} in custom symbol
  4558 definitions);
  4559 
  4560 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4561 state; Note that presentation of goal states does not conform to
  4562 actual human-readable proof documents.  Please do not include goal
  4563 states into document output unless you really know what you are doing!
  4564 
  4565 * proper indentation of antiquoted output with proportional LaTeX
  4566 fonts;
  4567 
  4568 * no_document ML operator temporarily disables LaTeX document
  4569 generation;
  4570 
  4571 * isatool unsymbolize tunes sources for plain ASCII communication;
  4572 
  4573 
  4574 *** Isar ***
  4575 
  4576 * Pure: Isar now suffers initial goal statements to contain unbound
  4577 schematic variables (this does not conform to actual readable proof
  4578 documents, due to unpredictable outcome and non-compositional proof
  4579 checking); users who know what they are doing may use schematic goals
  4580 for Prolog-style synthesis of proven results;
  4581 
  4582 * Pure: assumption method (an implicit finishing) now handles actual
  4583 rules as well;
  4584 
  4585 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4586 initial goal, declare "that" only as Pure intro (only for single
  4587 steps); the "that" rule assumption may now be involved in implicit
  4588 finishing, thus ".." becomes a feasible for trivial obtains;
  4589 
  4590 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4591 instance proofs may be performed by "..";
  4592 
  4593 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4594 statements as well;
  4595 
  4596 * Pure: more robust selection of calculational rules;
  4597 
  4598 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4599 rule (as well as the assumption rule);
  4600 
  4601 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4602 lemmas, using the graph browser tool;
  4603 
  4604 * Pure: predict failure of "show" in interactive mode;
  4605 
  4606 * Pure: 'thms_containing' now takes actual terms as arguments;
  4607 
  4608 * HOL: improved method 'induct' --- now handles non-atomic goals
  4609 (potential INCOMPATIBILITY); tuned error handling;
  4610 
  4611 * HOL: cases and induct rules now provide explicit hints about the
  4612 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4613 any remaining facts are inserted into the goal verbatim;
  4614 
  4615 * HOL: local contexts (aka cases) may now contain term bindings as
  4616 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4617 the result to be shown in each case;
  4618 
  4619 * HOL: added 'recdef_tc' command;
  4620 
  4621 * isatool convert assists in eliminating legacy ML scripts;
  4622 
  4623 
  4624 *** HOL ***
  4625 
  4626 * HOL/Library: a collection of generic theories to be used together
  4627 with main HOL; the theory loader path already includes this directory
  4628 by default; the following existing theories have been moved here:
  4629 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4630 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4631 
  4632 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4633 modelling and verification task performed in Isabelle/HOL +
  4634 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4635 
  4636 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4637 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4638 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4639 'domain', this makes the theory consistent with mathematical
  4640 literature;
  4641 
  4642 * HOL basics: added overloaded operations "inverse" and "divide"
  4643 (infix "/"), syntax for generic "abs" operation, generic summation
  4644 operator \<Sum>;
  4645 
  4646 * HOL/typedef: simplified package, provide more useful rules (see also
  4647 HOL/subset.thy);
  4648 
  4649 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4650 now expressed as a proper nested rule (old-style tactic scripts may
  4651 require atomize_strip_tac to cope with non-atomic premises);
  4652 
  4653 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4654 to "split_conv" (old name still available for compatibility);
  4655 
  4656 * HOL: improved concrete syntax for strings (e.g. allows translation
  4657 rules with string literals);
  4658 
  4659 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4660  and Fleuriot's mechanization of analysis, including the transcendental
  4661  functions for the reals;
  4662 
  4663 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4664 
  4665 
  4666 *** CTT ***
  4667 
  4668 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4669 "lam" is displayed as TWO lambda-symbols
  4670 
  4671 * CTT: theory Main now available, containing everything (that is, Bool
  4672 and Arith);
  4673 
  4674 
  4675 *** General ***
  4676 
  4677 * Pure: the Simplifier has been implemented properly as a derived rule
  4678 outside of the actual kernel (at last!); the overall performance
  4679 penalty in practical applications is about 50%, while reliability of
  4680 the Isabelle inference kernel has been greatly improved;
  4681 
  4682 * print modes "brackets" and "no_brackets" control output of nested =>
  4683 (types) and ==> (props); the default behaviour is "brackets";
  4684 
  4685 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4686 as assumptions as well;
  4687 
  4688 * system: support Poly/ML 4.0;
  4689 
  4690 * system: isatool install handles KDE version 1 or 2;
  4691 
  4692 
  4693 
  4694 New in Isabelle99-1 (October 2000)
  4695 ----------------------------------
  4696 
  4697 *** Overview of INCOMPATIBILITIES ***
  4698 
  4699 * HOL: simplification of natural numbers is much changed; to partly
  4700 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4701 issue the following ML commands:
  4702 
  4703   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4704   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4705 
  4706 * HOL: simplification no longer dives into case-expressions; this is
  4707 controlled by "t.weak_case_cong" for each datatype t;
  4708 
  4709 * HOL: nat_less_induct renamed to less_induct;
  4710 
  4711 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4712 fixsome to patch .thy and .ML sources automatically;
  4713 
  4714   select_equality  -> some_equality
  4715   select_eq_Ex     -> some_eq_ex
  4716   selectI2EX       -> someI2_ex
  4717   selectI2         -> someI2
  4718   selectI          -> someI
  4719   select1_equality -> some1_equality
  4720   Eps_sym_eq       -> some_sym_eq_trivial
  4721   Eps_eq           -> some_eq_trivial
  4722 
  4723 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4724 
  4725 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4726 instead);
  4727 
  4728 * HOL: the recursion equations generated by 'recdef' are now called
  4729 f.simps instead of f.rules;
  4730 
  4731 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4732 
  4733 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4734 sometimes be needed;
  4735 
  4736 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4737 
  4738 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4739 
  4740 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4741 product is now "<*>" instead of "Times"; the lexicographic product is
  4742 now "<*lex*>" instead of "**";
  4743 
  4744 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4745 of main HOL, but was unused); better use HOL's datatype package;
  4746 
  4747 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4748 the old syntax may be recovered as follows:
  4749 
  4750   syntax (symbols)
  4751     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4752       (infixl "\\<oplus>" 100)
  4753 
  4754 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4755 
  4756 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4757 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4758 internally;
  4759 
  4760 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4761 changed from A/r to A//r;
  4762 
  4763 * ZF: new treatment of arithmetic (nat & int) may break some old
  4764 proofs;
  4765 
  4766 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4767 rulify -> rule_format, elimify -> elim_format, ...);
  4768 
  4769 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4770 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4771 should have to change intro!! to intro? only); replaced "delrule" by
  4772 "rule del";
  4773 
  4774 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4775 
  4776 * Provers: strengthened force_tac by using new first_best_tac;
  4777 
  4778 * LaTeX document preparation: several changes of isabelle.sty (see
  4779 lib/texinputs);
  4780 
  4781 
  4782 *** Document preparation ***
  4783 
  4784 * formal comments (text blocks etc.) in new-style theories may now
  4785 contain antiquotations of thm/prop/term/typ/text to be presented
  4786 according to latex print mode; concrete syntax is like this:
  4787 @{term[show_types] "f(x) = a + x"};
  4788 
  4789 * isatool mkdir provides easy setup of Isabelle session directories,
  4790 including proper document sources;
  4791 
  4792 * generated LaTeX sources are now deleted after successful run
  4793 (isatool document -c); may retain a copy somewhere else via -D option
  4794 of isatool usedir;
  4795 
  4796 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4797 style files, achieving self-contained LaTeX sources and simplifying
  4798 LaTeX debugging;
  4799 
  4800 * old-style theories now produce (crude) LaTeX output as well;
  4801 
  4802 * browser info session directories are now self-contained (may be put
  4803 on WWW server seperately); improved graphs of nested sessions; removed
  4804 graph for 'all sessions';
  4805 
  4806 * several improvements in isabelle style files; \isabellestyle{it}
  4807 produces fake math mode output; \isamarkupheader is now \section by
  4808 default; see lib/texinputs/isabelle.sty etc.;
  4809 
  4810 
  4811 *** Isar ***
  4812 
  4813 * Isar/Pure: local results and corresponding term bindings are now
  4814 subject to Hindley-Milner polymorphism (similar to ML); this
  4815 accommodates incremental type-inference very nicely;
  4816 
  4817 * Isar/Pure: new derived language element 'obtain' supports
  4818 generalized existence reasoning;
  4819 
  4820 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4821 support accumulation of results, without applying any rules yet;
  4822 useful to collect intermediate results without explicit name
  4823 references, and for use with transitivity rules with more than 2
  4824 premises;
  4825 
  4826 * Isar/Pure: scalable support for case-analysis type proofs: new
  4827 'case' language element refers to local contexts symbolically, as
  4828 produced by certain proof methods; internally, case names are attached
  4829 to theorems as "tags";
  4830 
  4831 * Isar/Pure: theory command 'hide' removes declarations from
  4832 class/type/const name spaces;
  4833 
  4834 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4835 indicate potential overloading;
  4836 
  4837 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4838 
  4839 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4840 "{a,b,c}" instead of {a,b,c};
  4841 
  4842 * Isar/Pure now provides its own version of intro/elim/dest
  4843 attributes; useful for building new logics, but beware of confusion
  4844 with the version in Provers/classical;
  4845 
  4846 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4847 case name 'antecedent';
  4848 
  4849 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4850 to the current context is now done automatically);
  4851 
  4852 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4853 for definining proof methods in ML;
  4854 
  4855 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4856 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4857 most cases, one should have to change intro!! to intro? only);
  4858 replaced "delrule" by "rule del";
  4859 
  4860 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4861 'symmetric' attribute (the latter supercedes [RS sym]);
  4862 
  4863 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4864 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4865 well (including splits);
  4866 
  4867 * Isar/Provers: Simplifier and Classical methods now support all kind
  4868 of modifiers used in the past, including 'cong', 'iff', etc.
  4869 
  4870 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4871 of Simplifier and Classical reasoner);
  4872 
  4873 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4874 now support named cases; major packages (inductive, datatype, primrec,
  4875 recdef) support case names and properly name parameters;
  4876 
  4877 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4878 monotonicity conditions are extracted to be proven at end of
  4879 calculations;
  4880 
  4881 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4882 method anyway;
  4883 
  4884 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4885 split_if split_if_asm; datatype package provides theorems foo.splits =
  4886 foo.split foo.split_asm for each datatype;
  4887 
  4888 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4889 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4890 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4891 use "(cases (simplified))" method in proper proof texts);
  4892 
  4893 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4894 
  4895 * Isar: names of theorems etc. may be natural numbers as well;
  4896 
  4897 * Isar: 'pr' command: optional arguments for goals_limit and
  4898 ProofContext.prems_limit; no longer prints theory contexts, but only
  4899 proof states;
  4900 
  4901 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4902 additional print modes to be specified; e.g. "pr(latex)" will print
  4903 proof state according to the Isabelle LaTeX style;
  4904 
  4905 * Isar: improved support for emulating tactic scripts, including proof
  4906 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4907 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4908 (for HOL datatypes);
  4909 
  4910 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4911 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4912 'proof method scripts' have to be in depth-first order;
  4913 
  4914 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4915 
  4916 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4917 should instead use individual commands for printing items
  4918 (print_commands, print_methods etc.);
  4919 
  4920 * Isar: added 'nothing' --- the empty list of theorems;
  4921 
  4922 
  4923 *** HOL ***
  4924 
  4925 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4926 corresponding virtual machine and a specification of its bytecode
  4927 verifier and a lightweight bytecode verifier, including proofs of
  4928 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4929 Cornelia Pusch (see also the homepage of project Bali at
  4930 http://isabelle.in.tum.de/Bali/);
  4931 
  4932 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4933 Clemens Ballarin;
  4934 
  4935 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4936 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4937 Rasmussen;
  4938 
  4939 * HOL/Lattice: fundamental concepts of lattice theory and order
  4940 structures, including duals, properties of bounds versus algebraic
  4941 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4942 Theorem for complete lattices etc.; may also serve as a demonstration
  4943 for abstract algebraic reasoning using axiomatic type classes, and
  4944 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4945 
  4946 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4947 von Oheimb;
  4948 
  4949 * HOL/IMPP: extension of IMP with local variables and mutually
  4950 recursive procedures, by David von Oheimb;
  4951 
  4952 * HOL/Lambda: converted into new-style theory and document;
  4953 
  4954 * HOL/ex/Multiquote: example of multiple nested quotations and
  4955 anti-quotations -- basically a generalized version of de-Bruijn
  4956 representation; very useful in avoiding lifting of operations;
  4957 
  4958 * HOL/record: added general record equality rule to simpset; fixed
  4959 select-update simplification procedure to handle extended records as
  4960 well; admit "r" as field name;
  4961 
  4962 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4963 other numeric types and also as the identity of groups, rings, etc.;
  4964 
  4965 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4966 Types nat and int belong to this axclass;
  4967 
  4968 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4969    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4970    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4971   two terms #m*u and #n*u are replaced by #(m+n)*u
  4972     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4973   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4974     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4975 
  4976 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4977 powerful prover for predicate logic but knows nothing of clasets; see
  4978 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4979 
  4980 * HOL: new version of "case_tac" subsumes both boolean case split and
  4981 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4982 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4983 
  4984 * HOL: simplification no longer dives into case-expressions: only the
  4985 selector expression is simplified, but not the remaining arms; to
  4986 enable full simplification of case-expressions for datatype t, you may
  4987 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4988 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4989 
  4990 * HOL/recdef: the recursion equations generated by 'recdef' for
  4991 function 'f' are now called f.simps instead of f.rules; if all
  4992 termination conditions are proved automatically, these simplification
  4993 rules are added to the simpset, as in primrec; rules may be named
  4994 individually as well, resulting in a separate list of theorems for
  4995 each equation;
  4996 
  4997 * HOL/While is a new theory that provides a while-combinator. It
  4998 permits the definition of tail-recursive functions without the
  4999 provision of a termination measure. The latter is necessary once the
  5000 invariant proof rule for while is applied.
  5001 
  5002 * HOL: new (overloaded) notation for the set of elements below/above
  5003 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5004 
  5005 * HOL: theorems impI, allI, ballI bound as "strip";
  5006 
  5007 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5008 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5009 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5010 
  5011 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5012 
  5013 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5014 main HOL, but was unused);
  5015 
  5016 * HOL: fewer consts declared as global (e.g. have to refer to
  5017 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5018 
  5019 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5020 in case of overlap with user translations (e.g. judgements over
  5021 tuples); (note that the underlying logical represenation is still
  5022 bogus);
  5023 
  5024 
  5025 *** ZF ***
  5026 
  5027 * ZF: simplification automatically cancels common terms in arithmetic
  5028 expressions over nat and int;
  5029 
  5030 * ZF: new treatment of nat to minimize type-checking: all operators
  5031 coerce their operands to a natural number using the function natify,
  5032 making the algebraic laws unconditional;
  5033 
  5034 * ZF: as above, for int: operators coerce their operands to an integer
  5035 using the function intify;
  5036 
  5037 * ZF: the integer library now contains many of the usual laws for the
  5038 orderings, including $<=, and monotonicity laws for $+ and $*;
  5039 
  5040 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5041 simplification;
  5042 
  5043 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5044 to the simplifier and classical reasoner simultaneously;
  5045 
  5046 
  5047 *** General ***
  5048 
  5049 * Provers: blast_tac now handles actual object-logic rules as
  5050 assumptions; note that auto_tac uses blast_tac internally as well;
  5051 
  5052 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5053 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5054 
  5055 * Provers: delrules now handles destruct rules as well (no longer need
  5056 explicit make_elim);
  5057 
  5058 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5059   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5060 use instead the strong form,
  5061   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5062 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5063 from destruct-rules;
  5064 
  5065 * Provers: Simplifier.easy_setup provides a fast path to basic
  5066 Simplifier setup for new object-logics;
  5067 
  5068 * Pure: AST translation rules no longer require constant head on LHS;
  5069 
  5070 * Pure: improved name spaces: ambiguous output is qualified; support
  5071 for hiding of names;
  5072 
  5073 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5074 XSYMBOL_HOME; no longer need to do manual configuration in most
  5075 situations;
  5076 
  5077 * system: compression of ML heaps images may now be controlled via -c
  5078 option of isabelle and isatool usedir (currently only observed by
  5079 Poly/ML);
  5080 
  5081 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5082 useful for remote X11);
  5083 
  5084 * system: provide TAGS file for Isabelle sources;
  5085 
  5086 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5087 order;
  5088 
  5089 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5090 timing flag supersedes proof_timing and Toplevel.trace;
  5091 
  5092 * ML: new combinators |>> and |>>> for incremental transformations
  5093 with secondary results (e.g. certain theory extensions):
  5094 
  5095 * ML: PureThy.add_defs gets additional argument to indicate potential
  5096 overloading (usually false);
  5097 
  5098 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5099 results;
  5100 
  5101 
  5102 
  5103 New in Isabelle99 (October 1999)
  5104 --------------------------------
  5105 
  5106 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5107 
  5108 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5109 are no longer simplified.  (This allows the simplifier to unfold recursive
  5110 functional programs.)  To restore the old behaviour, declare
  5111 
  5112     Delcongs [if_weak_cong];
  5113 
  5114 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5115 complement;
  5116 
  5117 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5118 
  5119 * HOL/datatype: mutual_induct_tac no longer exists --
  5120   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5121 
  5122 * HOL/typedef: fixed type inference for representing set; type
  5123 arguments now have to occur explicitly on the rhs as type constraints;
  5124 
  5125 * ZF: The con_defs part of an inductive definition may no longer refer
  5126 to constants declared in the same theory;
  5127 
  5128 * HOL, ZF: the function mk_cases, generated by the inductive
  5129 definition package, has lost an argument.  To simplify its result, it
  5130 uses the default simpset instead of a supplied list of theorems.
  5131 
  5132 * HOL/List: the constructors of type list are now Nil and Cons;
  5133 
  5134 * Simplifier: the type of the infix ML functions
  5135         setSSolver addSSolver setSolver addSolver
  5136 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5137 for packaging solvers. A solver is created via
  5138         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5139 where the string argument is only a comment.
  5140 
  5141 
  5142 *** Proof tools ***
  5143 
  5144 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5145 decision procedure for linear arithmetic. Currently it is used for
  5146 types `nat', `int', and `real' in HOL (see below); it can, should and
  5147 will be instantiated for other types and logics as well.
  5148 
  5149 * The simplifier now accepts rewrite rules with flexible heads, eg
  5150      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5151   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5152   matching.
  5153 
  5154 
  5155 *** General ***
  5156 
  5157 * New Isabelle/Isar subsystem provides an alternative to traditional
  5158 tactical theorem proving; together with the ProofGeneral/isar user
  5159 interface it offers an interactive environment for developing human
  5160 readable proof documents (Isar == Intelligible semi-automated
  5161 reasoning); for further information see isatool doc isar-ref,
  5162 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5163 
  5164 * improved and simplified presentation of theories: better HTML markup
  5165 (including colors), graph views in several sizes; isatool usedir now
  5166 provides a proper interface for user theories (via -P option); actual
  5167 document preparation based on (PDF)LaTeX is available as well (for
  5168 new-style theories only); see isatool doc system for more information;
  5169 
  5170 * native support for Proof General, both for classic Isabelle and
  5171 Isabelle/Isar;
  5172 
  5173 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5174 using the graph browser tool;
  5175 
  5176 * Isabelle manuals now also available as PDF;
  5177 
  5178 * theory loader rewritten from scratch (may not be fully
  5179 bug-compatible); old loadpath variable has been replaced by show_path,
  5180 add_path, del_path, reset_path functions; new operations such as
  5181 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5182 isatool doc ref);
  5183 
  5184 * improved isatool install: option -k creates KDE application icon,
  5185 option -p DIR installs standalone binaries;
  5186 
  5187 * added ML_PLATFORM setting (useful for cross-platform installations);
  5188 more robust handling of platform specific ML images for SML/NJ;
  5189 
  5190 * the settings environment is now statically scoped, i.e. it is never
  5191 created again in sub-processes invoked from isabelle, isatool, or
  5192 Isabelle;
  5193 
  5194 * path element specification '~~' refers to '$ISABELLE_HOME';
  5195 
  5196 * in locales, the "assumes" and "defines" parts may be omitted if
  5197 empty;
  5198 
  5199 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5200 long arrows);
  5201 
  5202 * new print_mode "HTML";
  5203 
  5204 * new flag show_tags controls display of tags of theorems (which are
  5205 basically just comments that may be attached by some tools);
  5206 
  5207 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5208 mode and goal output format:
  5209 
  5210 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5211 244c244
  5212 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5213 ---
  5214 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5215 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5216 181c181
  5217 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5218 ---
  5219 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5220 
  5221 * function bind_thms stores lists of theorems (cf. bind_thm);
  5222 
  5223 * new shorthand tactics ftac, eatac, datac, fatac;
  5224 
  5225 * qed (and friends) now accept "" as result name; in that case the
  5226 theorem is not stored, but proper checks and presentation of the
  5227 result still apply;
  5228 
  5229 * theorem database now also indexes constants "Trueprop", "all",
  5230 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5231 
  5232 
  5233 *** HOL ***
  5234 
  5235 ** HOL arithmetic **
  5236 
  5237 * There are now decision procedures for linear arithmetic over nat and
  5238 int:
  5239 
  5240 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5241 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5242 are treated as atomic; subformulae not involving type `nat' or `int'
  5243 are ignored; quantified subformulae are ignored unless they are
  5244 positive universal or negative existential. The tactic has to be
  5245 invoked by hand and can be a little bit slow. In particular, the
  5246 running time is exponential in the number of occurrences of `min' and
  5247 `max', and `-' on `nat'.
  5248 
  5249 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5250 (negated) (in)equalities among the premises and the conclusion into
  5251 account (i.e. no compound formulae) and does not know about `min' and
  5252 `max', and `-' on `nat'. It is fast and is used automatically by the
  5253 simplifier.
  5254 
  5255 NB: At the moment, these decision procedures do not cope with mixed
  5256 nat/int formulae where the two parts interact, such as `m < n ==>
  5257 int(m) < int(n)'.
  5258 
  5259 * HOL/Numeral provides a generic theory of numerals (encoded
  5260 efficiently as bit strings); setup for types nat/int/real is in place;
  5261 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5262 int, existing theories and proof scripts may require a few additional
  5263 type constraints;
  5264 
  5265 * integer division and remainder can now be performed on constant
  5266 arguments;
  5267 
  5268 * many properties of integer multiplication, division and remainder
  5269 are now available;
  5270 
  5271 * An interface to the Stanford Validity Checker (SVC) is available through the
  5272 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5273 are proved automatically.  SVC must be installed separately, and its results
  5274 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5275 invocation of the underlying oracle).  For SVC see
  5276   http://verify.stanford.edu/SVC
  5277 
  5278 * IsaMakefile: the HOL-Real target now builds an actual image;
  5279 
  5280 
  5281 ** HOL misc **
  5282 
  5283 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5284 (in Isabelle/Isar) -- by Gertrud Bauer;
  5285 
  5286 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5287 analysis for assembly languages with subtypes;
  5288 
  5289 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5290 -- avoids syntactic ambiguities and treats state, transition, and
  5291 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5292 changed syntax and (many) tactics;
  5293 
  5294 * HOL/inductive: Now also handles more general introduction rules such
  5295   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5296   theorems are now maintained within the theory (maintained via the
  5297   "mono" attribute);
  5298 
  5299 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5300   (using function types) such as
  5301 
  5302   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5303 
  5304 * HOL/record: record_simproc (part of the default simpset) takes care
  5305 of selectors applied to updated records; record_split_tac is no longer
  5306 part of the default claset; update_defs may now be removed from the
  5307 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5308 
  5309   claset_ref () := claset() addSWrapper record_split_wrapper;
  5310   Delsimprocs [record_simproc]
  5311 
  5312 * HOL/typedef: fixed type inference for representing set; type
  5313 arguments now have to occur explicitly on the rhs as type constraints;
  5314 
  5315 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5316 names rather than an ML expression;
  5317 
  5318 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5319 supplied later.  Program schemes can be defined, such as
  5320     "While B C s = (if B s then While B C (C s) else s)"
  5321 where the well-founded relation can be chosen after B and C have been given.
  5322 
  5323 * HOL/List: the constructors of type list are now Nil and Cons;
  5324 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5325 course, ML tools referring to List.list.op # etc. have to be adapted;
  5326 
  5327 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5328 disabled by default; run isabelle with option -m HOL to get back to
  5329 the original Gordon/HOL-style output;
  5330 
  5331 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5332 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5333 
  5334 * HOL basic syntax simplified (more orthogonal): all variants of
  5335 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5336 Eps operator is provided as well: "SOME x. P[x]";
  5337 
  5338 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5339 
  5340 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5341 thus available for user theories;
  5342 
  5343 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5344 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5345 time;
  5346 
  5347 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5348 several times and then mp;
  5349 
  5350 
  5351 *** LK ***
  5352 
  5353 * the notation <<...>> is now available as a notation for sequences of
  5354 formulas;
  5355 
  5356 * the simplifier is now installed
  5357 
  5358 * the axiom system has been generalized (thanks to Soren Heilmann)
  5359 
  5360 * the classical reasoner now has a default rule database
  5361 
  5362 
  5363 *** ZF ***
  5364 
  5365 * new primrec section allows primitive recursive functions to be given
  5366 directly (as in HOL) over datatypes and the natural numbers;
  5367 
  5368 * new tactics induct_tac and exhaust_tac for induction (or case
  5369 analysis) over datatypes and the natural numbers;
  5370 
  5371 * the datatype declaration of type T now defines the recursor T_rec;
  5372 
  5373 * simplification automatically does freeness reasoning for datatype
  5374 constructors;
  5375 
  5376 * automatic type-inference, with AddTCs command to insert new
  5377 type-checking rules;
  5378 
  5379 * datatype introduction rules are now added as Safe Introduction rules
  5380 to the claset;
  5381 
  5382 * the syntax "if P then x else y" is now available in addition to
  5383 if(P,x,y);
  5384 
  5385 
  5386 *** Internal programming interfaces ***
  5387 
  5388 * tuned simplifier trace output; new flag debug_simp;
  5389 
  5390 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5391 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5392 
  5393 * AxClass.axclass_tac lost the theory argument;
  5394 
  5395 * tuned current_goals_markers semantics: begin / end goal avoids
  5396 printing empty lines;
  5397 
  5398 * removed prs and prs_fn hook, which was broken because it did not
  5399 include \n in its semantics, forcing writeln to add one
  5400 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5401 string -> unit if you really want to output text without newline;
  5402 
  5403 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5404 plain output, interface builders may have to enable 'isabelle_font'
  5405 mode to get Isabelle font glyphs as before;
  5406 
  5407 * refined token_translation interface; INCOMPATIBILITY: output length
  5408 now of type real instead of int;
  5409 
  5410 * theory loader actions may be traced via new ThyInfo.add_hook
  5411 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5412 your own database of information attached to *whole* theories -- as
  5413 opposed to intra-theory data slots offered via TheoryDataFun;
  5414 
  5415 * proper handling of dangling sort hypotheses (at last!);
  5416 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5417 extra sort hypotheses that can be witnessed from the type signature;
  5418 the force_strip_shyps flag is gone, any remaining shyps are simply
  5419 left in the theorem (with a warning issued by strip_shyps_warning);
  5420 
  5421 
  5422 
  5423 New in Isabelle98-1 (October 1998)
  5424 ----------------------------------
  5425 
  5426 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5427 
  5428 * several changes of automated proof tools;
  5429 
  5430 * HOL: major changes to the inductive and datatype packages, including
  5431 some minor incompatibilities of theory syntax;
  5432 
  5433 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5434 called `inj_on';
  5435 
  5436 * HOL: removed duplicate thms in Arith:
  5437   less_imp_add_less  should be replaced by  trans_less_add1
  5438   le_imp_add_le      should be replaced by  trans_le_add1
  5439 
  5440 * HOL: unary minus is now overloaded (new type constraints may be
  5441 required);
  5442 
  5443 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5444 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5445 now taken as an integer constant.
  5446 
  5447 * Pure: ML function 'theory_of' renamed to 'theory';
  5448 
  5449 
  5450 *** Proof tools ***
  5451 
  5452 * Simplifier:
  5453   1. Asm_full_simp_tac is now more aggressive.
  5454      1. It will sometimes reorient premises if that increases their power to
  5455         simplify.
  5456      2. It does no longer proceed strictly from left to right but may also
  5457         rotate premises to achieve further simplification.
  5458      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5459      old Asm_full_simp_tac in that it does not rotate premises.
  5460   2. The simplifier now knows a little bit about nat-arithmetic.
  5461 
  5462 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5463 allows for selected deletion of wrappers, by introduction of names for
  5464 wrapper functionals.  This implies that addbefore, addSbefore,
  5465 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5466 and that adding two tactics with the same name overwrites the first
  5467 one (emitting a warning).
  5468   type wrapper = (int -> tactic) -> (int -> tactic)
  5469   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5470   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5471   delWrapper, delSWrapper: claset *  string            -> claset
  5472   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5473 
  5474 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5475 semantics; addbefore now affects only the unsafe part of step_tac
  5476 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5477 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5478 by Force_tac;
  5479 
  5480 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5481 compWrapper; added safe wrapper (and access functions for it);
  5482 
  5483 * HOL/split_all_tac is now much faster and fails if there is nothing
  5484 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5485 and the names of the automatically generated variables have changed.
  5486 split_all_tac has moved within claset() from unsafe wrappers to safe
  5487 wrappers, which means that !!-bound variables are split much more
  5488 aggressively, and safe_tac and clarify_tac now split such variables.
  5489 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5490 Note: the same holds for record_split_tac, which does the job of
  5491 split_all_tac for record fields.
  5492 
  5493 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5494 permanently to the default simpset using Addsplits just like
  5495 Addsimps. They can be removed via Delsplits just like
  5496 Delsimps. Lower-case versions are also available.
  5497 
  5498 * HOL/Simplifier: The rule split_if is now part of the default
  5499 simpset. This means that the simplifier will eliminate all occurrences
  5500 of if-then-else in the conclusion of a goal. To prevent this, you can
  5501 either remove split_if completely from the default simpset by
  5502 `Delsplits [split_if]' or remove it in a specific call of the
  5503 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5504 other case splitting rules to/from the default simpset: every datatype
  5505 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5506 t is the name of the datatype).
  5507 
  5508 * Classical reasoner / Simplifier combination: new force_tac (and
  5509 derivatives Force_tac, force) combines rewriting and classical
  5510 reasoning (and whatever other tools) similarly to auto_tac, but is
  5511 aimed to solve the given subgoal completely.
  5512 
  5513 
  5514 *** General ***
  5515 
  5516 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5517 and `goalw': the theory is no longer needed as an explicit argument -
  5518 the current theory context is used; assumptions are no longer returned
  5519 at the ML-level unless one of them starts with ==> or !!; it is
  5520 recommended to convert to these new commands using isatool fixgoal
  5521 (backup your sources first!);
  5522 
  5523 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5524 the current theory context, and 'theory' to lookup stored theories;
  5525 
  5526 * new theory section 'locale' for declaring constants, assumptions and
  5527 definitions that have local scope;
  5528 
  5529 * new theory section 'nonterminals' for purely syntactic types;
  5530 
  5531 * new theory section 'setup' for generic ML setup functions
  5532 (e.g. package initialization);
  5533 
  5534 * the distribution now includes Isabelle icons: see
  5535 lib/logo/isabelle-{small,tiny}.xpm;
  5536 
  5537 * isatool install - install binaries with absolute references to
  5538 ISABELLE_HOME/bin;
  5539 
  5540 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5541 
  5542 * print mode 'emacs' reserved for Isamode;
  5543 
  5544 * support multiple print (ast) translations per constant name;
  5545 
  5546 * theorems involving oracles are now printed with a suffixed [!];
  5547 
  5548 
  5549 *** HOL ***
  5550 
  5551 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5552 
  5553 * HOL/inductive package reorganized and improved: now supports mutual
  5554 definitions such as
  5555 
  5556   inductive EVEN ODD
  5557     intrs
  5558       null "0 : EVEN"
  5559       oddI "n : EVEN ==> Suc n : ODD"
  5560       evenI "n : ODD ==> Suc n : EVEN"
  5561 
  5562 new theorem list "elims" contains an elimination rule for each of the
  5563 recursive sets; inductive definitions now handle disjunctive premises
  5564 correctly (also ZF);
  5565 
  5566 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5567 "mutual_induct" no longer exists - the induction rule is always
  5568 contained in "induct";
  5569 
  5570 
  5571 * HOL/datatype package re-implemented and greatly improved: now
  5572 supports mutually recursive datatypes such as
  5573 
  5574   datatype
  5575     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5576             | SUM ('a aexp) ('a aexp)
  5577             | DIFF ('a aexp) ('a aexp)
  5578             | NUM 'a
  5579   and
  5580     'a bexp = LESS ('a aexp) ('a aexp)
  5581             | AND ('a bexp) ('a bexp)
  5582             | OR ('a bexp) ('a bexp)
  5583 
  5584 as well as indirectly recursive datatypes such as
  5585 
  5586   datatype
  5587     ('a, 'b) term = Var 'a
  5588                   | App 'b ((('a, 'b) term) list)
  5589 
  5590 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5591 induction on mutually / indirectly recursive datatypes.
  5592 
  5593 Primrec equations are now stored in theory and can be accessed via
  5594 <function_name>.simps.
  5595 
  5596 INCOMPATIBILITIES:
  5597 
  5598   - Theories using datatypes must now have theory Datatype as an
  5599     ancestor.
  5600   - The specific <typename>.induct_tac no longer exists - use the
  5601     generic induct_tac instead.
  5602   - natE has been renamed to nat.exhaust - use exhaust_tac
  5603     instead of res_inst_tac ... natE. Note that the variable
  5604     names in nat.exhaust differ from the names in natE, this
  5605     may cause some "fragile" proofs to fail.
  5606   - The theorems split_<typename>_case and split_<typename>_case_asm
  5607     have been renamed to <typename>.split and <typename>.split_asm.
  5608   - Since default sorts of type variables are now handled correctly,
  5609     some datatype definitions may have to be annotated with explicit
  5610     sort constraints.
  5611   - Primrec definitions no longer require function name and type
  5612     of recursive argument.
  5613 
  5614 Consider using isatool fixdatatype to adapt your theories and proof
  5615 scripts to the new package (backup your sources first!).
  5616 
  5617 
  5618 * HOL/record package: considerably improved implementation; now
  5619 includes concrete syntax for record types, terms, updates; theorems
  5620 for surjective pairing and splitting !!-bound record variables; proof
  5621 support is as follows:
  5622 
  5623   1) standard conversions (selectors or updates applied to record
  5624 constructor terms) are part of the standard simpset;
  5625 
  5626   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5627 made part of standard simpset and claset via addIffs;
  5628 
  5629   3) a tactic for record field splitting (record_split_tac) is part of
  5630 the standard claset (addSWrapper);
  5631 
  5632 To get a better idea about these rules you may retrieve them via
  5633 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5634 the name of your record type.
  5635 
  5636 The split tactic 3) conceptually simplifies by the following rule:
  5637 
  5638   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5639 
  5640 Thus any record variable that is bound by meta-all will automatically
  5641 blow up into some record constructor term, consequently the
  5642 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5643 solve record problems automatically.
  5644 
  5645 
  5646 * reorganized the main HOL image: HOL/Integ and String loaded by
  5647 default; theory Main includes everything;
  5648 
  5649 * automatic simplification of integer sums and comparisons, using cancellation;
  5650 
  5651 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5652 
  5653 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5654 
  5655 * many new identities for unions, intersections, set difference, etc.;
  5656 
  5657 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5658 called split_if, split_split, split_sum_case and split_nat_case (to go
  5659 with add/delsplits);
  5660 
  5661 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5662 (?x::unit) = (); this is made part of the default simpset, which COULD
  5663 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5664 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5665 unit_abs_eta_conv is added in order to counter the effect of
  5666 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5667 %u.f();
  5668 
  5669 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5670 makes more sense);
  5671 
  5672 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5673   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5674   disjointness reasoning but breaking a few old proofs.
  5675 
  5676 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5677 to 'converse' from 'inverse' (for compatibility with ZF and some
  5678 literature);
  5679 
  5680 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5681 the well-founded relation;
  5682 
  5683 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5684     Compl A.  The "Compl" syntax remains available as input syntax for this
  5685     release ONLY.
  5686 
  5687 * HOL/Update: new theory of function updates:
  5688     f(a:=b) == %x. if x=a then b else f x
  5689 may also be iterated as in f(a:=b,c:=d,...);
  5690 
  5691 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5692 
  5693 * HOL/List:
  5694   - new function list_update written xs[i:=v] that updates the i-th
  5695     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5696   - new function `upt' written [i..j(] which generates the list
  5697     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5698     bound write [i..j], which is a shorthand for [i..j+1(].
  5699   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5700 
  5701 * HOL/Arith:
  5702   - removed 'pred' (predecessor) function;
  5703   - generalized some theorems about n-1;
  5704   - many new laws about "div" and "mod";
  5705   - new laws about greatest common divisors (see theory ex/Primes);
  5706 
  5707 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5708 instead of "inverse";
  5709 
  5710 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5711   of the multiset ordering;
  5712 
  5713 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5714   (not included by default);
  5715 
  5716 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5717 
  5718 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5719   programs, i.e. different program variables may have different types.
  5720 
  5721 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5722   [previously, this check worked only if the rewrite rule was unconditional]
  5723   Now rew can involve either definitions or equalities (either == or =).
  5724 
  5725 
  5726 *** ZF ***
  5727 
  5728 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5729   only the theorems proved on ZF.ML;
  5730 
  5731 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5732   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5733   disjointness reasoning but breaking a few old proofs.
  5734 
  5735 * ZF/Update: new theory of function updates
  5736     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5737   may also be iterated as in f(a:=b,c:=d,...);
  5738 
  5739 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5740 
  5741 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5742   [previously, this check worked only if the rewrite rule was unconditional]
  5743   Now rew can involve either definitions or equalities (either == or =).
  5744 
  5745 * case_tac provided for compatibility with HOL
  5746     (like the old excluded_middle_tac, but with subgoals swapped)
  5747 
  5748 
  5749 *** Internal programming interfaces ***
  5750 
  5751 * Pure: several new basic modules made available for general use, see
  5752 also src/Pure/README;
  5753 
  5754 * improved the theory data mechanism to support encapsulation (data
  5755 kind name replaced by private Object.kind, acting as authorization
  5756 key); new type-safe user interface via functor TheoryDataFun; generic
  5757 print_data function becomes basically useless;
  5758 
  5759 * removed global_names compatibility flag -- all theory declarations
  5760 are qualified by default;
  5761 
  5762 * module Pure/Syntax now offers quote / antiquote translation
  5763 functions (useful for Hoare logic etc. with implicit dependencies);
  5764 see HOL/ex/Antiquote for an example use;
  5765 
  5766 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5767 cterm -> thm;
  5768 
  5769 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5770 subgoal;
  5771 
  5772 * Display.print_goals function moved to Locale.print_goals;
  5773 
  5774 * standard print function for goals supports current_goals_markers
  5775 variable for marking begin of proof, end of proof, start of goal; the
  5776 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5777 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5778 for example;
  5779 
  5780 
  5781 
  5782 New in Isabelle98 (January 1998)
  5783 --------------------------------
  5784 
  5785 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5786 
  5787 * changed lexical syntax of terms / types: dots made part of long
  5788 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5789 
  5790 * simpset (and claset) reference variable replaced by functions
  5791 simpset / simpset_ref;
  5792 
  5793 * no longer supports theory aliases (via merge) and non-trivial
  5794 implicit merge of thms' signatures;
  5795 
  5796 * most internal names of constants changed due to qualified names;
  5797 
  5798 * changed Pure/Sequence interface (see Pure/seq.ML);
  5799 
  5800 
  5801 *** General Changes ***
  5802 
  5803 * hierachically structured name spaces (for consts, types, axms, thms
  5804 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5805 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5806 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5807 long_names for fully qualified output names; NOTE: ML programs
  5808 (special tactics, packages etc.) referring to internal names may have
  5809 to be adapted to cope with fully qualified names; in case of severe
  5810 backward campatibility problems try setting 'global_names' at compile
  5811 time to have enrything declared within a flat name space; one may also
  5812 fine tune name declarations in theories via the 'global' and 'local'
  5813 section;
  5814 
  5815 * reimplemented the implicit simpset and claset using the new anytype
  5816 data filed in signatures; references simpset:simpset ref etc. are
  5817 replaced by functions simpset:unit->simpset and
  5818 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5819 to patch your ML files accordingly;
  5820 
  5821 * HTML output now includes theory graph data for display with Java
  5822 applet or isatool browser; data generated automatically via isatool
  5823 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5824 
  5825 * defs may now be conditional; improved rewrite_goals_tac to handle
  5826 conditional equations;
  5827 
  5828 * defs now admits additional type arguments, using TYPE('a) syntax;
  5829 
  5830 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5831 creates a new theory node; implicit merge of thms' signatures is
  5832 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5833 transfer:theory->thm->thm in (rare) cases;
  5834 
  5835 * improved handling of draft signatures / theories; draft thms (and
  5836 ctyps, cterms) are automatically promoted to real ones;
  5837 
  5838 * slightly changed interfaces for oracles: admit many per theory, named
  5839 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5840 
  5841 * print_goals: optional output of const types (set show_consts and
  5842 show_types);
  5843 
  5844 * improved output of warnings (###) and errors (***);
  5845 
  5846 * subgoal_tac displays a warning if the new subgoal has type variables;
  5847 
  5848 * removed old README and Makefiles;
  5849 
  5850 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5851 
  5852 * removed obsolete init_pps and init_database;
  5853 
  5854 * deleted the obsolete tactical STATE, which was declared by
  5855     fun STATE tacfun st = tacfun st st;
  5856 
  5857 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5858 (which abbreviates $HOME);
  5859 
  5860 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5861 use isatool fixseq to adapt your ML programs (this works for fully
  5862 qualified references to the Sequence structure only!);
  5863 
  5864 * use_thy no longer requires writable current directory; it always
  5865 reloads .ML *and* .thy file, if either one is out of date;
  5866 
  5867 
  5868 *** Classical Reasoner ***
  5869 
  5870 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5871 tactics that use classical reasoning to simplify a subgoal without
  5872 splitting it into several subgoals;
  5873 
  5874 * Safe_tac: like safe_tac but uses the default claset;
  5875 
  5876 
  5877 *** Simplifier ***
  5878 
  5879 * added simplification meta rules:
  5880     (asm_)(full_)simplify: simpset -> thm -> thm;
  5881 
  5882 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5883 logics (again);
  5884 
  5885 * added prems argument to simplification procedures;
  5886 
  5887 * HOL, FOL, ZF: added infix function `addsplits':
  5888   instead of `<simpset> setloop (split_tac <thms>)'
  5889   you can simply write `<simpset> addsplits <thms>'
  5890 
  5891 
  5892 *** Syntax ***
  5893 
  5894 * TYPE('a) syntax for type reflection terms;
  5895 
  5896 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5897 
  5898 * pretty printer: changed order of mixfix annotation preference (again!);
  5899 
  5900 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5901 
  5902 
  5903 *** HOL ***
  5904 
  5905 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5906   with `addloop' of the simplifier to faciliate case splitting in premises.
  5907 
  5908 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5909 
  5910 * HOL/Auth: new protocol proofs including some for the Internet
  5911   protocol TLS;
  5912 
  5913 * HOL/Map: new theory of `maps' a la VDM;
  5914 
  5915 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5916 cancelling out common nat summands from =, <, <= (in)equalities, or
  5917 differences; simplification procedures nat_cancel_factor for
  5918 cancelling common factor from =, <, <= (in)equalities over natural
  5919 sums; nat_cancel contains both kinds of procedures, it is installed by
  5920 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5921 
  5922 * HOL/simplifier: terms of the form
  5923   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5924   are rewritten to
  5925   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5926   and those of the form
  5927   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5928   are rewritten to
  5929   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5930 
  5931 * HOL/datatype
  5932   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5933 
  5934   P(t_case f1 ... fn x) =
  5935      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5936         ...
  5937        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5938      )
  5939 
  5940   and a theorem `split_t_case_asm' of the form
  5941 
  5942   P(t_case f1 ... fn x) =
  5943     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5944         ...
  5945        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5946      )
  5947   which can be added to a simpset via `addsplits'. The existing theorems
  5948   expand_list_case and expand_option_case have been renamed to
  5949   split_list_case and split_option_case.
  5950 
  5951 * HOL/Arithmetic:
  5952   - `pred n' is automatically converted to `n-1'.
  5953     Users are strongly encouraged not to use `pred' any longer,
  5954     because it will disappear altogether at some point.
  5955   - Users are strongly encouraged to write "0 < n" rather than
  5956     "n ~= 0". Theorems and proof tools have been modified towards this
  5957     `standard'.
  5958 
  5959 * HOL/Lists:
  5960   the function "set_of_list" has been renamed "set" (and its theorems too);
  5961   the function "nth" now takes its arguments in the reverse order and
  5962   has acquired the infix notation "!" as in "xs!n".
  5963 
  5964 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5965 
  5966 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5967   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5968 
  5969 * HOL/record: extensible records with schematic structural subtyping
  5970 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5971 still lacks various theorems and concrete record syntax;
  5972 
  5973 
  5974 *** HOLCF ***
  5975 
  5976 * removed "axioms" and "generated by" sections;
  5977 
  5978 * replaced "ops" section by extended "consts" section, which is capable of
  5979   handling the continuous function space "->" directly;
  5980 
  5981 * domain package:
  5982   . proves theorems immediately and stores them in the theory,
  5983   . creates hierachical name space,
  5984   . now uses normal mixfix annotations (instead of cinfix...),
  5985   . minor changes to some names and values (for consistency),
  5986   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5987   . separator between mutual domain defs: changed "," to "and",
  5988   . improved handling of sort constraints;  now they have to
  5989     appear on the left-hand side of the equations only;
  5990 
  5991 * fixed LAM <x,y,zs>.b syntax;
  5992 
  5993 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5994 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5995 
  5996 
  5997 *** FOL and ZF ***
  5998 
  5999 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6000   with `addloop' of the simplifier to faciliate case splitting in premises.
  6001 
  6002 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6003 in HOL, they strip ALL and --> from proved theorems;
  6004 
  6005 
  6006 
  6007 New in Isabelle94-8 (May 1997)
  6008 ------------------------------
  6009 
  6010 *** General Changes ***
  6011 
  6012 * new utilities to build / run / maintain Isabelle etc. (in parts
  6013 still somewhat experimental); old Makefiles etc. still functional;
  6014 
  6015 * new 'Isabelle System Manual';
  6016 
  6017 * INSTALL text, together with ./configure and ./build scripts;
  6018 
  6019 * reimplemented type inference for greater efficiency, better error
  6020 messages and clean internal interface;
  6021 
  6022 * prlim command for dealing with lots of subgoals (an easier way of
  6023 setting goals_limit);
  6024 
  6025 
  6026 *** Syntax ***
  6027 
  6028 * supports alternative (named) syntax tables (parser and pretty
  6029 printer); internal interface is provided by add_modesyntax(_i);
  6030 
  6031 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6032 be used in conjunction with the Isabelle symbol font; uses the
  6033 "symbols" syntax table;
  6034 
  6035 * added token_translation interface (may translate name tokens in
  6036 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6037 the current print_mode); IMPORTANT: user print translation functions
  6038 are responsible for marking newly introduced bounds
  6039 (Syntax.mark_boundT);
  6040 
  6041 * token translations for modes "xterm" and "xterm_color" that display
  6042 names in bold, underline etc. or colors (which requires a color
  6043 version of xterm);
  6044 
  6045 * infixes may now be declared with names independent of their syntax;
  6046 
  6047 * added typed_print_translation (like print_translation, but may
  6048 access type of constant);
  6049 
  6050 
  6051 *** Classical Reasoner ***
  6052 
  6053 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6054 some limitations.  Blast_tac...
  6055   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6056   + ignores elimination rules that don't have the correct format
  6057         (the conclusion MUST be a formula variable)
  6058   + ignores types, which can make HOL proofs fail
  6059   + rules must not require higher-order unification, e.g. apply_type in ZF
  6060     [message "Function Var's argument not a bound variable" relates to this]
  6061   + its proof strategy is more general but can actually be slower
  6062 
  6063 * substitution with equality assumptions no longer permutes other
  6064 assumptions;
  6065 
  6066 * minor changes in semantics of addafter (now called addaltern); renamed
  6067 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6068 (and access functions for it);
  6069 
  6070 * improved combination of classical reasoner and simplifier:
  6071   + functions for handling clasimpsets
  6072   + improvement of addss: now the simplifier is called _after_ the
  6073     safe steps.
  6074   + safe variant of addss called addSss: uses safe simplifications
  6075     _during_ the safe steps. It is more complete as it allows multiple
  6076     instantiations of unknowns (e.g. with slow_tac).
  6077 
  6078 *** Simplifier ***
  6079 
  6080 * added interface for simplification procedures (functions that
  6081 produce *proven* rewrite rules on the fly, depending on current
  6082 redex);
  6083 
  6084 * ordering on terms as parameter (used for ordered rewriting);
  6085 
  6086 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6087 
  6088 * the solver is now split into a safe and an unsafe part.
  6089 This should be invisible for the normal user, except that the
  6090 functions setsolver and addsolver have been renamed to setSolver and
  6091 addSolver; added safe_asm_full_simp_tac;
  6092 
  6093 
  6094 *** HOL ***
  6095 
  6096 * a generic induction tactic `induct_tac' which works for all datatypes and
  6097 also for type `nat';
  6098 
  6099 * a generic case distinction tactic `exhaust_tac' which works for all
  6100 datatypes and also for type `nat';
  6101 
  6102 * each datatype comes with a function `size';
  6103 
  6104 * patterns in case expressions allow tuple patterns as arguments to
  6105 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6106 
  6107 * primrec now also works with type nat;
  6108 
  6109 * recdef: a new declaration form, allows general recursive functions to be
  6110 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6111 
  6112 * the constant for negation has been renamed from "not" to "Not" to
  6113 harmonize with FOL, ZF, LK, etc.;
  6114 
  6115 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6116 infinite lists;
  6117 
  6118 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6119 
  6120 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6121 problems in commutative rings, using axiomatic type classes for + and *;
  6122 
  6123 * more examples in HOL/MiniML and HOL/Auth;
  6124 
  6125 * more default rewrite rules for quantifiers, union/intersection;
  6126 
  6127 * a new constant `arbitrary == @x.False';
  6128 
  6129 * HOLCF/IOA replaces old HOL/IOA;
  6130 
  6131 * HOLCF changes: derived all rules and arities
  6132   + axiomatic type classes instead of classes
  6133   + typedef instead of faking type definitions
  6134   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6135   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6136   + eliminated the types void, one, tr
  6137   + use unit lift and bool lift (with translations) instead of one and tr
  6138   + eliminated blift from Lift3.thy (use Def instead of blift)
  6139   all eliminated rules are derived as theorems --> no visible changes ;
  6140 
  6141 
  6142 *** ZF ***
  6143 
  6144 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6145 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6146 as ZF_cs addSIs [equalityI];
  6147 
  6148 
  6149 
  6150 New in Isabelle94-7 (November 96)
  6151 ---------------------------------
  6152 
  6153 * allowing negative levels (as offsets) in prlev and choplev;
  6154 
  6155 * super-linear speedup for large simplifications;
  6156 
  6157 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6158 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6159 FAIL); can suppress it using the command Delsimps (ex_simps @
  6160 all_simps); De Morgan laws are also now included, by default;
  6161 
  6162 * improved printing of ==>  :  ~:
  6163 
  6164 * new object-logic "Sequents" adds linear logic, while replacing LK
  6165 and Modal (thanks to Sara Kalvala);
  6166 
  6167 * HOL/Auth: correctness proofs for authentication protocols;
  6168 
  6169 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6170 examples on HOL/Auth);
  6171 
  6172 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6173 the rewriter and classical reasoner simultaneously;
  6174 
  6175 * function uresult no longer returns theorems in "standard" format;
  6176 regain previous version by: val uresult = standard o uresult;
  6177 
  6178 
  6179 
  6180 New in Isabelle94-6
  6181 -------------------
  6182 
  6183 * oracles -- these establish an interface between Isabelle and trusted
  6184 external reasoners, which may deliver results as theorems;
  6185 
  6186 * proof objects (in particular record all uses of oracles);
  6187 
  6188 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6189 
  6190 * "constdefs" section in theory files;
  6191 
  6192 * "primrec" section (HOL) no longer requires names;
  6193 
  6194 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6195 
  6196 
  6197 
  6198 New in Isabelle94-5
  6199 -------------------
  6200 
  6201 * reduced space requirements;
  6202 
  6203 * automatic HTML generation from theories;
  6204 
  6205 * theory files no longer require "..." (quotes) around most types;
  6206 
  6207 * new examples, including two proofs of the Church-Rosser theorem;
  6208 
  6209 * non-curried (1994) version of HOL is no longer distributed;
  6210 
  6211 
  6212 
  6213 New in Isabelle94-4
  6214 -------------------
  6215 
  6216 * greatly reduced space requirements;
  6217 
  6218 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6219 
  6220 * searchable theorem database (see the section "Retrieving theorems" on
  6221 page 8 of the Reference Manual);
  6222 
  6223 * new examples, including Grabczewski's monumental case study of the
  6224 Axiom of Choice;
  6225 
  6226 * The previous version of HOL renamed to Old_HOL;
  6227 
  6228 * The new version of HOL (previously called CHOL) uses a curried syntax
  6229 for functions.  Application looks like f a b instead of f(a,b);
  6230 
  6231 * Mutually recursive inductive definitions finally work in HOL;
  6232 
  6233 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6234 translates to the operator "split";
  6235 
  6236 
  6237 
  6238 New in Isabelle94-3
  6239 -------------------
  6240 
  6241 * new infix operator, addss, allowing the classical reasoner to
  6242 perform simplification at each step of its search.  Example:
  6243         fast_tac (cs addss ss)
  6244 
  6245 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6246 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6247 look like (a,b) instead of <a,b>;
  6248 
  6249 * PLEASE NOTE: CHOL will eventually replace HOL!
  6250 
  6251 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6252 It translates to the operator "split".  A new theory of integers is available;
  6253 
  6254 * In ZF, integer numerals now denote two's-complement binary integers.
  6255 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6256 
  6257 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6258 of the Axiom of Choice;
  6259 
  6260 
  6261