NEWS
author haftmann
Fri Jun 19 17:23:21 2009 +0200 (2009-06-19)
changeset 31723 f5cafe803b55
parent 31643 b040f1679f77
child 31726 ffd2dc631d88
permissions -rw-r--r--
discontinued ancient tradition to suffix certain ML module names with "_package"
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Discontinued old form of "escaped symbols" such as \\<forall>.  Only
    10 one backslash should be used, even in ML sources.
    11 
    12 
    13 *** Pure ***
    14 
    15 * On instantiation of classes, remaining undefined class parameters
    16 are formally declared.  INCOMPATIBILITY.
    17 
    18 
    19 *** HOL ***
    20 
    21 * Class semiring_div requires superclass no_zero_divisors and proof of
    22 div_mult_mult1; theorems div_mult_mult1, div_mult_mult2,
    23 div_mult_mult1_if, div_mult_mult1 and div_mult_mult2 have been
    24 generalized to class semiring_div, subsuming former theorems
    25 zdiv_zmult_zmult1, zdiv_zmult_zmult1_if, zdiv_zmult_zmult1 and
    26 zdiv_zmult_zmult2.  div_mult_mult1 is now [simp] by default.
    27 INCOMPATIBILITY.
    28 
    29 * Power operations on relations and functions are now one dedicate
    30 constant compow with infix syntax "^^".  Power operations on
    31 multiplicative monoids retains syntax "^" and is now defined generic
    32 in class power.  INCOMPATIBILITY.
    33 
    34 * ML antiquotation @{code_datatype} inserts definition of a datatype
    35 generated by the code generator; see Predicate.thy for an example.
    36 
    37 * New method "linarith" invokes existing linear arithmetic decision
    38 procedure only.
    39 
    40 * Implementation of quickcheck using generic code generator; default generators
    41 are provided for all suitable HOL types, records and datatypes.
    42 
    43 * Constants Set.Pow and Set.image now with authentic syntax; object-logic definitions
    44 Set.Pow_def and Set.image_def.  INCOMPATIBILITY.
    45 
    46 * Discontinued ancient tradition to suffix certain ML module names with "_package", e.g.:
    47 
    48     DatatypePackage ~> Datatype
    49     InductivePackage ~> Inductive
    50 
    51     etc.
    52 
    53 INCOMPATIBILITY.
    54 
    55 
    56 
    57 *** ML ***
    58 
    59 * Eliminated old Attrib.add_attributes, Method.add_methods and related
    60 cominators for "args".  INCOMPATIBILITY, need to use simplified
    61 Attrib/Method.setup introduced in Isabelle2009.
    62 
    63 
    64 *** System ***
    65 
    66 * Discontinued support for Poly/ML 4.x versions.
    67 
    68 * Removed "compress" option from isabelle-process and isabelle usedir;
    69 this is always enabled.
    70 
    71 
    72 
    73 New in Isabelle2009 (April 2009)
    74 --------------------------------
    75 
    76 *** General ***
    77 
    78 * Simplified main Isabelle executables, with less surprises on
    79 case-insensitive file-systems (such as Mac OS).
    80 
    81   - The main Isabelle tool wrapper is now called "isabelle" instead of
    82     "isatool."
    83 
    84   - The former "isabelle" alias for "isabelle-process" has been
    85     removed (should rarely occur to regular users).
    86 
    87   - The former "isabelle-interface" and its alias "Isabelle" have been
    88     removed (interfaces are now regular Isabelle tools).
    89 
    90 Within scripts and make files, the Isabelle environment variables
    91 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    92 respectively.  (The latter are still available as legacy feature.)
    93 
    94 The old isabelle-interface wrapper could react in confusing ways if
    95 the interface was uninstalled or changed otherwise.  Individual
    96 interface tool configuration is now more explicit, see also the
    97 Isabelle system manual.  In particular, Proof General is now available
    98 via "isabelle emacs".
    99 
   100 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
   101 purge installed copies of Isabelle executables and re-run "isabelle
   102 install -p ...", or use symlinks.
   103 
   104 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
   105 old ~/isabelle, which was slightly non-standard and apt to cause
   106 surprises on case-insensitive file-systems (such as Mac OS).
   107 
   108 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
   109 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
   110 care is required when using older releases of Isabelle.  Note that
   111 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
   112 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
   113 
   114 * Proofs of fully specified statements are run in parallel on
   115 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
   116 a regular 4-core machine, if the initial heap space is made reasonably
   117 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
   118 
   119 * The main reference manuals ("isar-ref", "implementation", and
   120 "system") have been updated and extended.  Formally checked references
   121 as hyperlinks are now available uniformly.
   122 
   123 
   124 *** Pure ***
   125 
   126 * Complete re-implementation of locales.  INCOMPATIBILITY in several
   127 respects.  The most important changes are listed below.  See the
   128 Tutorial on Locales ("locales" manual) for details.
   129 
   130 - In locale expressions, instantiation replaces renaming.  Parameters
   131 must be declared in a for clause.  To aid compatibility with previous
   132 parameter inheritance, in locale declarations, parameters that are not
   133 'touched' (instantiation position "_" or omitted) are implicitly added
   134 with their syntax at the beginning of the for clause.
   135 
   136 - Syntax from abbreviations and definitions in locales is available in
   137 locale expressions and context elements.  The latter is particularly
   138 useful in locale declarations.
   139 
   140 - More flexible mechanisms to qualify names generated by locale
   141 expressions.  Qualifiers (prefixes) may be specified in locale
   142 expressions, and can be marked as mandatory (syntax: "name!:") or
   143 optional (syntax "name?:").  The default depends for plain "name:"
   144 depends on the situation where a locale expression is used: in
   145 commands 'locale' and 'sublocale' prefixes are optional, in
   146 'interpretation' and 'interpret' prefixes are mandatory.  The old
   147 implicit qualifiers derived from the parameter names of a locale are
   148 no longer generated.
   149 
   150 - Command "sublocale l < e" replaces "interpretation l < e".  The
   151 instantiation clause in "interpretation" and "interpret" (square
   152 brackets) is no longer available.  Use locale expressions.
   153 
   154 - When converting proof scripts, mandatory qualifiers in
   155 'interpretation' and 'interpret' should be retained by default, even
   156 if this is an INCOMPATIBILITY compared to former behavior.  In the
   157 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   158 in locale expressions range over a single locale instance only.
   159 
   160 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   161 In existing theorem specifications replace the includes element by the
   162 respective context elements of the included locale, omitting those
   163 that are already present in the theorem specification.  Multiple
   164 assume elements of a locale should be replaced by a single one
   165 involving the locale predicate.  In the proof body, declarations (most
   166 notably theorems) may be regained by interpreting the respective
   167 locales in the proof context as required (command "interpret").
   168 
   169 If using "includes" in replacement of a target solely because the
   170 parameter types in the theorem are not as general as in the target,
   171 consider declaring a new locale with additional type constraints on
   172 the parameters (context element "constrains").
   173 
   174 - Discontinued "locale (open)".  INCOMPATIBILITY.
   175 
   176 - Locale interpretation commands no longer attempt to simplify goal.
   177 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   178 methods intro_locales and unfold_locales to clarify.
   179 
   180 - Locale interpretation commands no longer accept interpretation
   181 attributes.  INCOMPATIBILITY.
   182 
   183 * Class declaration: so-called "base sort" must not be given in import
   184 list any longer, but is inferred from the specification.  Particularly
   185 in HOL, write
   186 
   187     class foo = ...
   188 
   189 instead of
   190 
   191     class foo = type + ...
   192 
   193 * Class target: global versions of theorems stemming do not carry a
   194 parameter prefix any longer.  INCOMPATIBILITY.
   195 
   196 * Class 'instance' command no longer accepts attached definitions.
   197 INCOMPATIBILITY, use proper 'instantiation' target instead.
   198 
   199 * Recovered hiding of consts, which was accidentally broken in
   200 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   201 makes c inaccessible; consider using ``hide (open) const c'' instead.
   202 
   203 * Slightly more coherent Pure syntax, with updated documentation in
   204 isar-ref manual.  Removed locales meta_term_syntax and
   205 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   206 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   207 directly in regular applications.
   208 
   209 * There is a new syntactic category "float_const" for signed decimal
   210 fractions (e.g. 123.45 or -123.45).
   211 
   212 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   213 interface with 'setup' command instead.
   214 
   215 * Command 'local_setup' is similar to 'setup', but operates on a local
   216 theory context.
   217 
   218 * The 'axiomatization' command now only works within a global theory
   219 context.  INCOMPATIBILITY.
   220 
   221 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   222 hypotheses.  Sorts required in the course of reasoning need to be
   223 covered by the constraints in the initial statement, completed by the
   224 type instance information of the background theory.  Non-trivial sort
   225 hypotheses, which rarely occur in practice, may be specified via
   226 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   227 
   228   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   229 
   230 The result contains an implicit sort hypotheses as before --
   231 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   232 normalization.
   233 
   234 * Generalized Isar history, with support for linear undo, direct state
   235 addressing etc.
   236 
   237 * Changed defaults for unify configuration options:
   238 
   239   unify_trace_bound = 50 (formerly 25)
   240   unify_search_bound = 60 (formerly 30)
   241 
   242 * Different bookkeeping for code equations (INCOMPATIBILITY):
   243 
   244   a) On theory merge, the last set of code equations for a particular
   245      constant is taken (in accordance with the policy applied by other
   246      parts of the code generator framework).
   247 
   248   b) Code equations stemming from explicit declarations (e.g. code
   249      attribute) gain priority over default code equations stemming
   250      from definition, primrec, fun etc.
   251 
   252 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   253 
   254 * Unified theorem tables for both code generators.  Thus [code
   255 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   256 
   257 * Command 'find_consts' searches for constants based on type and name
   258 patterns, e.g.
   259 
   260     find_consts "_ => bool"
   261 
   262 By default, matching is against subtypes, but it may be restricted to
   263 the whole type.  Searching by name is possible.  Multiple queries are
   264 conjunctive and queries may be negated by prefixing them with a
   265 hyphen:
   266 
   267     find_consts strict: "_ => bool" name: "Int" -"int => int"
   268 
   269 * New 'find_theorems' criterion "solves" matches theorems that
   270 directly solve the current goal (modulo higher-order unification).
   271 
   272 * Auto solve feature for main theorem statements: whenever a new goal
   273 is stated, "find_theorems solves" is called; any theorems that could
   274 solve the lemma directly are listed as part of the goal state.
   275 Cf. associated options in Proof General Isabelle settings menu,
   276 enabled by default, with reasonable timeout for pathological cases of
   277 higher-order unification.
   278 
   279 
   280 *** Document preparation ***
   281 
   282 * Antiquotation @{lemma} now imitates a regular terminal proof,
   283 demanding keyword 'by' and supporting the full method expression
   284 syntax just like the Isar command 'by'.
   285 
   286 
   287 *** HOL ***
   288 
   289 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   290 points Main and Complex_Main remain as before.
   291 
   292 * Logic image HOL-Plain provides a minimal HOL with the most important
   293 tools available (inductive, datatype, primrec, ...).  This facilitates
   294 experimentation and tool development.  Note that user applications
   295 (and library theories) should never refer to anything below theory
   296 Main, as before.
   297 
   298 * Logic image HOL-Main stops at theory Main, and thus facilitates
   299 experimentation due to shorter build times.
   300 
   301 * Logic image HOL-NSA contains theories of nonstandard analysis which
   302 were previously part of former HOL-Complex.  Entry point Hyperreal
   303 remains valid, but theories formerly using Complex_Main should now use
   304 new entry point Hypercomplex.
   305 
   306 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   307 Posix processes.  Avoids potentially expensive forking of the ML
   308 process.  New thread-based implementation also works on non-Unix
   309 platforms (Cygwin).  Provers are no longer hardwired, but defined
   310 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   311 commands are covered in the isar-ref manual.
   312 
   313 * Wrapper scripts for remote SystemOnTPTP service allows to use
   314 sledgehammer without local ATP installation (Vampire etc.). Other
   315 provers may be included via suitable ML wrappers, see also
   316 src/HOL/ATP_Linkup.thy.
   317 
   318 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   319 menu.
   320 
   321 * The metis method no longer fails because the theorem is too trivial
   322 (contains the empty clause).
   323 
   324 * The metis method now fails in the usual manner, rather than raising
   325 an exception, if it determines that it cannot prove the theorem.
   326 
   327 * Method "coherent" implements a prover for coherent logic (see also
   328 src/Tools/coherent.ML).
   329 
   330 * Constants "undefined" and "default" replace "arbitrary".  Usually
   331 "undefined" is the right choice to replace "arbitrary", though
   332 logically there is no difference.  INCOMPATIBILITY.
   333 
   334 * Command "value" now integrates different evaluation mechanisms.  The
   335 result of the first successful evaluation mechanism is printed.  In
   336 square brackets a particular named evaluation mechanisms may be
   337 specified (currently, [SML], [code] or [nbe]).  See further
   338 src/HOL/ex/Eval_Examples.thy.
   339 
   340 * Normalization by evaluation now allows non-leftlinear equations.
   341 Declare with attribute [code nbe].
   342 
   343 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   344 as the structured Isar versions "cases" and "induct", cf. the
   345 corresponding "cases" and "induct" attributes.  Mutual induction rules
   346 are now presented as a list of individual projections
   347 (e.g. foo_bar.inducts for types foo and bar); the old format with
   348 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   349 rare situations a different rule is selected --- notably nested tuple
   350 elimination instead of former prod.exhaust: use explicit (case_tac t
   351 rule: prod.exhaust) here.
   352 
   353 * Attributes "cases", "induct", "coinduct" support "del" option.
   354 
   355 * Removed fact "case_split_thm", which duplicates "case_split".
   356 
   357 * The option datatype has been moved to a new theory Option.  Renamed
   358 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   359 
   360 * New predicate "strict_mono" classifies strict functions on partial
   361 orders.  With strict functions on linear orders, reasoning about
   362 (in)equalities is facilitated by theorems "strict_mono_eq",
   363 "strict_mono_less_eq" and "strict_mono_less".
   364 
   365 * Some set operations are now proper qualified constants with
   366 authentic syntax.  INCOMPATIBILITY:
   367 
   368     op Int ~>   Set.Int
   369     op Un ~>    Set.Un
   370     INTER ~>    Set.INTER
   371     UNION ~>    Set.UNION
   372     Inter ~>    Set.Inter
   373     Union ~>    Set.Union
   374     {} ~>       Set.empty
   375     UNIV ~>     Set.UNIV
   376 
   377 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   378 theory Set.
   379 
   380 * Auxiliary class "itself" has disappeared -- classes without any
   381 parameter are treated as expected by the 'class' command.
   382 
   383 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   384 
   385 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   386 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   387 
   388 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   389 method "approximation".  It proves formulas on real values by using
   390 interval arithmetic.  In the formulas are also the transcendental
   391 functions sin, cos, tan, atan, ln, exp and the constant pi are
   392 allowed. For examples see
   393 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   394 
   395 * Theory "Reflection" now resides in HOL/Library.
   396 
   397 * Entry point to Word library now simply named "Word".
   398 INCOMPATIBILITY.
   399 
   400 * Made source layout more coherent with logical distribution
   401 structure:
   402 
   403     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   404     src/HOL/Library/Code_Message.thy ~> src/HOL/
   405     src/HOL/Library/GCD.thy ~> src/HOL/
   406     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   407     src/HOL/Library/Parity.thy ~> src/HOL/
   408     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   409     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   410     src/HOL/Real/Lubs.thy ~> src/HOL/
   411     src/HOL/Real/PReal.thy ~> src/HOL/
   412     src/HOL/Real/Rational.thy ~> src/HOL/
   413     src/HOL/Real/RComplete.thy ~> src/HOL/
   414     src/HOL/Real/RealDef.thy ~> src/HOL/
   415     src/HOL/Real/RealPow.thy ~> src/HOL/
   416     src/HOL/Real/Real.thy ~> src/HOL/
   417     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   418     src/HOL/Complex/Complex.thy ~> src/HOL/
   419     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   420     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   421     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   422     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   423     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   424     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   425     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   426     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   427     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   428     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   429     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   430     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   431     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   432     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   433     src/HOL/Real/Float ~> src/HOL/Library/
   434     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   435     src/HOL/Real/RealVector.thy ~> src/HOL/
   436 
   437     src/HOL/arith_data.ML ~> src/HOL/Tools
   438     src/HOL/hologic.ML ~> src/HOL/Tools
   439     src/HOL/simpdata.ML ~> src/HOL/Tools
   440     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   441     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   442     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   443     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   444     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   445     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   446     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   447 
   448     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   449     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   450     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   451     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   452     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   453     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   454 
   455 * If methods "eval" and "evaluation" encounter a structured proof
   456 state with !!/==>, only the conclusion is evaluated to True (if
   457 possible), avoiding strange error messages.
   458 
   459 * Method "sizechange" automates termination proofs using (a
   460 modification of) the size-change principle.  Requires SAT solver.  See
   461 src/HOL/ex/Termination.thy for examples.
   462 
   463 * Simplifier: simproc for let expressions now unfolds if bound
   464 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   465 
   466 * Method "arith": Linear arithmetic now ignores all inequalities when
   467 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   468 
   469 * New attribute "arith" for facts that should always be used
   470 automatically by arithmetic. It is intended to be used locally in
   471 proofs, e.g.
   472 
   473   assumes [arith]: "x > 0"
   474 
   475 Global usage is discouraged because of possible performance impact.
   476 
   477 * New classes "top" and "bot" with corresponding operations "top" and
   478 "bot" in theory Orderings; instantiation of class "complete_lattice"
   479 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   480 
   481 * Changed definition lemma "less_fun_def" in order to provide an
   482 instance for preorders on functions; use lemma "less_le" instead.
   483 INCOMPATIBILITY.
   484 
   485 * Theory Orderings: class "wellorder" moved here, with explicit
   486 induction rule "less_induct" as assumption.  For instantiation of
   487 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   488 INCOMPATIBILITY.
   489 
   490 * Theory Orderings: added class "preorder" as superclass of "order".
   491 INCOMPATIBILITY: Instantiation proofs for order, linorder
   492 etc. slightly changed.  Some theorems named order_class.* now named
   493 preorder_class.*.
   494 
   495 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   496 "diag" to "Id_on".
   497 
   498 * Theory Finite_Set: added a new fold combinator of type
   499 
   500   ('a => 'b => 'b) => 'b => 'a set => 'b
   501 
   502 Occasionally this is more convenient than the old fold combinator
   503 which is now defined in terms of the new one and renamed to
   504 fold_image.
   505 
   506 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   507 and "ring_simps" have been replaced by "algebra_simps" (which can be
   508 extended with further lemmas!).  At the moment both still exist but
   509 the former will disappear at some point.
   510 
   511 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   512 class recpower.  Type-specific simp rules for various recpower types
   513 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   514 
   515 rat_power_0    -> power_0
   516 rat_power_Suc  -> power_Suc
   517 realpow_0      -> power_0
   518 realpow_Suc    -> power_Suc
   519 complexpow_0   -> power_0
   520 complexpow_Suc -> power_Suc
   521 power_poly_0   -> power_0
   522 power_poly_Suc -> power_Suc
   523 
   524 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   525 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   526 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   527 of lemmas from Divides has been generalized from nat to class
   528 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   529 renames resulting from duplicate elimination:
   530 
   531     dvd_def_mod ~>          dvd_eq_mod_eq_0
   532     zero_dvd_iff ~>         dvd_0_left_iff
   533     dvd_0 ~>                dvd_0_right
   534     DIVISION_BY_ZERO_DIV ~> div_by_0
   535     DIVISION_BY_ZERO_MOD ~> mod_by_0
   536     mult_div ~>             div_mult_self2_is_id
   537     mult_mod ~>             mod_mult_self2_is_0
   538 
   539 * Theory IntDiv: removed many lemmas that are instances of class-based
   540 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   541 rename old lemmas as follows:
   542 
   543 dvd_diff               -> nat_dvd_diff
   544 dvd_zminus_iff         -> dvd_minus_iff
   545 mod_add1_eq            -> mod_add_eq
   546 mod_mult1_eq           -> mod_mult_right_eq
   547 mod_mult1_eq'          -> mod_mult_left_eq
   548 mod_mult_distrib_mod   -> mod_mult_eq
   549 nat_mod_add_left_eq    -> mod_add_left_eq
   550 nat_mod_add_right_eq   -> mod_add_right_eq
   551 nat_mod_div_trivial    -> mod_div_trivial
   552 nat_mod_mod_trivial    -> mod_mod_trivial
   553 zdiv_zadd_self1        -> div_add_self1
   554 zdiv_zadd_self2        -> div_add_self2
   555 zdiv_zmult_self1       -> div_mult_self2_is_id
   556 zdiv_zmult_self2       -> div_mult_self1_is_id
   557 zdvd_triv_left         -> dvd_triv_left
   558 zdvd_triv_right        -> dvd_triv_right
   559 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   560 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   561 zmod_zadd_left_eq      -> mod_add_left_eq
   562 zmod_zadd_right_eq     -> mod_add_right_eq
   563 zmod_zadd_self1        -> mod_add_self1
   564 zmod_zadd_self2        -> mod_add_self2
   565 zmod_zadd1_eq          -> mod_add_eq
   566 zmod_zdiff1_eq         -> mod_diff_eq
   567 zmod_zdvd_zmod         -> mod_mod_cancel
   568 zmod_zmod_cancel       -> mod_mod_cancel
   569 zmod_zmult_self1       -> mod_mult_self2_is_0
   570 zmod_zmult_self2       -> mod_mult_self1_is_0
   571 zmod_1                 -> mod_by_1
   572 zdiv_1                 -> div_by_1
   573 zdvd_abs1              -> abs_dvd_iff
   574 zdvd_abs2              -> dvd_abs_iff
   575 zdvd_refl              -> dvd_refl
   576 zdvd_trans             -> dvd_trans
   577 zdvd_zadd              -> dvd_add
   578 zdvd_zdiff             -> dvd_diff
   579 zdvd_zminus_iff        -> dvd_minus_iff
   580 zdvd_zminus2_iff       -> minus_dvd_iff
   581 zdvd_zmultD            -> dvd_mult_right
   582 zdvd_zmultD2           -> dvd_mult_left
   583 zdvd_zmult_mono        -> mult_dvd_mono
   584 zdvd_0_right           -> dvd_0_right
   585 zdvd_0_left            -> dvd_0_left_iff
   586 zdvd_1_left            -> one_dvd
   587 zminus_dvd_iff         -> minus_dvd_iff
   588 
   589 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   590 
   591 * The real numbers offer decimal input syntax: 12.34 is translated
   592 into 1234/10^2. This translation is not reversed upon output.
   593 
   594 * Theory Library/Polynomial defines an abstract type 'a poly of
   595 univariate polynomials with coefficients of type 'a.  In addition to
   596 the standard ring operations, it also supports div and mod.  Code
   597 generation is also supported, using list-style constructors.
   598 
   599 * Theory Library/Inner_Product defines a class of real_inner for real
   600 inner product spaces, with an overloaded operation inner :: 'a => 'a
   601 => real.  Class real_inner is a subclass of real_normed_vector from
   602 theory RealVector.
   603 
   604 * Theory Library/Product_Vector provides instances for the product
   605 type 'a * 'b of several classes from RealVector and Inner_Product.
   606 Definitions of addition, subtraction, scalar multiplication, norms,
   607 and inner products are included.
   608 
   609 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   610 addition to the field operations, numerals and case syntax are also
   611 supported.
   612 
   613 * Theory Library/Diagonalize provides constructive version of Cantor's
   614 first diagonalization argument.
   615 
   616 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   617 zlcm (for int); carried together from various gcd/lcm developements in
   618 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   619 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   620 may recover tupled syntax as follows:
   621 
   622     hide (open) const gcd
   623     abbreviation gcd where
   624       "gcd == (%(a, b). GCD.gcd a b)"
   625     notation (output)
   626       GCD.gcd ("gcd '(_, _')")
   627 
   628 The same works for lcm, zgcd, zlcm.
   629 
   630 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   631 instantiations for algebraic structures.  Removed some duplicate
   632 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   633 
   634 * ML antiquotation @{code} takes a constant as argument and generates
   635 corresponding code in background and inserts name of the corresponding
   636 resulting ML value/function/datatype constructor binding in place.
   637 All occurrences of @{code} with a single ML block are generated
   638 simultaneously.  Provides a generic and safe interface for
   639 instrumentalizing code generation.  See
   640 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   641 In future you ought to refrain from ad-hoc compiling generated SML
   642 code on the ML toplevel.  Note that (for technical reasons) @{code}
   643 cannot refer to constants for which user-defined serializations are
   644 set.  Refer to the corresponding ML counterpart directly in that
   645 cases.
   646 
   647 * Command 'rep_datatype': instead of theorem names the command now
   648 takes a list of terms denoting the constructors of the type to be
   649 represented as datatype.  The characteristic theorems have to be
   650 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   651 have disappeared in favour of existing ones:
   652 
   653     unit_induct                 ~> unit.induct
   654     prod_induct                 ~> prod.induct
   655     sum_induct                  ~> sum.induct
   656     Suc_Suc_eq                  ~> nat.inject
   657     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   658 
   659 
   660 *** HOL-Algebra ***
   661 
   662 * New locales for orders and lattices where the equivalence relation
   663 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   664 locales use a record structure with field eq for the equivalence.
   665 
   666 * New theory of factorial domains.
   667 
   668 * Units_l_inv and Units_r_inv are now simp rules by default.
   669 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   670 and/or r_inv will now also require deletion of these lemmas.
   671 
   672 * Renamed the following theorems, INCOMPATIBILITY:
   673 
   674 UpperD ~> Upper_memD
   675 LowerD ~> Lower_memD
   676 least_carrier ~> least_closed
   677 greatest_carrier ~> greatest_closed
   678 greatest_Lower_above ~> greatest_Lower_below
   679 one_zero ~> carrier_one_zero
   680 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   681 
   682 
   683 *** HOL-Nominal ***
   684 
   685 * Nominal datatypes can now contain type-variables.
   686 
   687 * Commands 'nominal_inductive' and 'equivariance' work with local
   688 theory targets.
   689 
   690 * Nominal primrec can now works with local theory targets and its
   691 specification syntax now conforms to the general format as seen in
   692 'inductive' etc.
   693 
   694 * Method "perm_simp" honours the standard simplifier attributes
   695 (no_asm), (no_asm_use) etc.
   696 
   697 * The new predicate #* is defined like freshness, except that on the
   698 left hand side can be a set or list of atoms.
   699 
   700 * Experimental command 'nominal_inductive2' derives strong induction
   701 principles for inductive definitions.  In contrast to
   702 'nominal_inductive', which can only deal with a fixed number of
   703 binders, it can deal with arbitrary expressions standing for sets of
   704 atoms to be avoided.  The only inductive definition we have at the
   705 moment that needs this generalisation is the typing rule for Lets in
   706 the algorithm W:
   707 
   708  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   709  -----------------------------------------------------------------
   710          Gamma |- Let x be t1 in t2 : T2
   711 
   712 In this rule one wants to avoid all the binders that are introduced by
   713 "close Gamma T1".  We are looking for other examples where this
   714 feature might be useful.  Please let us know.
   715 
   716 
   717 *** HOLCF ***
   718 
   719 * Reimplemented the simplification procedure for proving continuity
   720 subgoals.  The new simproc is extensible; users can declare additional
   721 continuity introduction rules with the attribute [cont2cont].
   722 
   723 * The continuity simproc now uses a different introduction rule for
   724 solving continuity subgoals on terms with lambda abstractions.  In
   725 some rare cases the new simproc may fail to solve subgoals that the
   726 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   727 Potential INCOMPATIBILITY.
   728 
   729 * Command 'fixrec': specification syntax now conforms to the general
   730 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   731 examples.  INCOMPATIBILITY.
   732 
   733 
   734 *** ZF ***
   735 
   736 * Proof of Zorn's Lemma for partial orders.
   737 
   738 
   739 *** ML ***
   740 
   741 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   742 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   743 depends on multithreading, so timouts will not work before Poly/ML
   744 5.2.1!
   745 
   746 * High-level support for concurrent ML programming, see
   747 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   748 particularly convenient to organize independent functional
   749 computations.  The concept of "synchronized variables" provides a
   750 higher-order interface for components with shared state, avoiding the
   751 delicate details of mutexes and condition variables.  (Requires
   752 Poly/ML 5.2.1 or later.)
   753 
   754 * ML bindings produced via Isar commands are stored within the Isar
   755 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   756 become thread-safe and work with undo as expected (concerning
   757 top-level bindings, not side-effects on global references).
   758 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   759 compiler at runtime; really global bindings need to be given outside a
   760 theory.  (Requires Poly/ML 5.2 or later.)
   761 
   762 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   763 context.  Top-level ML bindings are stored within the proof context in
   764 a purely sequential fashion, disregarding the nested proof structure.
   765 ML bindings introduced by 'ML_prf' are discarded at the end of the
   766 proof.  (Requires Poly/ML 5.2 or later.)
   767 
   768 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   769 and Method.setup, as well as Isar commands 'attribute_setup' and
   770 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   771 existing code accordingly, or use plain 'setup' together with old
   772 Method.add_method.
   773 
   774 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   775 to 'a -> thm, while results are always tagged with an authentic oracle
   776 name.  The Isar command 'oracle' is now polymorphic, no argument type
   777 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   778 accordingly.  Note that extra performance may be gained by producing
   779 the cterm carefully, avoiding slow Thm.cterm_of.
   780 
   781 * Simplified interface for defining document antiquotations via
   782 ThyOutput.antiquotation, ThyOutput.output, and optionally
   783 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   784 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   785 examples.
   786 
   787 * More systematic treatment of long names, abstract name bindings, and
   788 name space operations.  Basic operations on qualified names have been
   789 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   790 Long_Name.append.  Old type bstring has been mostly replaced by
   791 abstract type binding (see structure Binding), which supports precise
   792 qualification by packages and local theory targets, as well as proper
   793 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   794 bstring values into Binding.name, or better pass through abstract
   795 bindings everywhere.  See further src/Pure/General/long_name.ML,
   796 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   797 
   798 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   799 LocalTheory.note etc.) now refer to the *full* internal name, not the
   800 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   801 
   802 * Disposed old type and term read functions (Sign.read_def_typ,
   803 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   804 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   805 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   806 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   807 resort for legacy applications.
   808 
   809 * Disposed old declarations, tactics, tactic combinators that refer to
   810 the simpset or claset of an implicit theory (such as Addsimps,
   811 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   812 embedded ML text, or local_simpset_of with a proper context passed as
   813 explicit runtime argument.
   814 
   815 * Rules and tactics that read instantiations (read_instantiate,
   816 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   817 context, which is required for parsing and type-checking.  Moreover,
   818 the variables are specified as plain indexnames, not string encodings
   819 thereof.  INCOMPATIBILITY.
   820 
   821 * Generic Toplevel.add_hook interface allows to analyze the result of
   822 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   823 for theorem dependency output of transactions resulting in a new
   824 theory state.
   825 
   826 * ML antiquotations: block-structured compilation context indicated by
   827 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   828 
   829   @{binding name}                         - basic name binding
   830   @{let ?pat = term}                      - term abbreviation (HO matching)
   831   @{note name = fact}                     - fact abbreviation
   832   @{thm fact}                             - singleton fact (with attributes)
   833   @{thms fact}                            - general fact (with attributes)
   834   @{lemma prop by method}                 - singleton goal
   835   @{lemma prop by meth1 meth2}            - singleton goal
   836   @{lemma prop1 ... propN by method}      - general goal
   837   @{lemma prop1 ... propN by meth1 meth2} - general goal
   838   @{lemma (open) ...}                     - open derivation
   839 
   840 
   841 *** System ***
   842 
   843 * The Isabelle "emacs" tool provides a specific interface to invoke
   844 Proof General / Emacs, with more explicit failure if that is not
   845 installed (the old isabelle-interface script silently falls back on
   846 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   847 installation location of the Proof General distribution.
   848 
   849 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   850 the Isabelle process into a JVM/Scala application.  See
   851 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   852 process wrapper has been discontinued.)
   853 
   854 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   855 
   856 * Various status messages (with exact source position information) are
   857 emitted, if proper markup print mode is enabled.  This allows
   858 user-interface components to provide detailed feedback on internal
   859 prover operations.
   860 
   861 
   862 
   863 New in Isabelle2008 (June 2008)
   864 -------------------------------
   865 
   866 *** General ***
   867 
   868 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   869 and updated, with formally checked references as hyperlinks.
   870 
   871 * Theory loader: use_thy (and similar operations) no longer set the
   872 implicit ML context, which was occasionally hard to predict and in
   873 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   874 provides a proper context already.
   875 
   876 * Theory loader: old-style ML proof scripts being *attached* to a thy
   877 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   878 'use' within a theory file will do the job.
   879 
   880 * Name space merge now observes canonical order, i.e. the second space
   881 is inserted into the first one, while existing entries in the first
   882 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   883 swap theory imports.
   884 
   885 * Syntax: symbol \<chi> is now considered a letter.  Potential
   886 INCOMPATIBILITY in identifier syntax etc.
   887 
   888 * Outer syntax: string tokens no longer admit escaped white space,
   889 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   890 white space without escapes.
   891 
   892 * Outer syntax: string tokens may contain arbitrary character codes
   893 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   894 "foo_bar".
   895 
   896 
   897 *** Pure ***
   898 
   899 * Context-dependent token translations.  Default setup reverts locally
   900 fixed variables, and adds hilite markup for undeclared frees.
   901 
   902 * Unused theorems can be found using the new command 'unused_thms'.
   903 There are three ways of invoking it:
   904 
   905 (1) unused_thms
   906      Only finds unused theorems in the current theory.
   907 
   908 (2) unused_thms thy_1 ... thy_n -
   909      Finds unused theorems in the current theory and all of its ancestors,
   910      excluding the theories thy_1 ... thy_n and all of their ancestors.
   911 
   912 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   913      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   914      their ancestors, excluding the theories thy_1 ... thy_n and all of
   915      their ancestors.
   916 
   917 In order to increase the readability of the list produced by
   918 unused_thms, theorems that have been created by a particular instance
   919 of a theory command such as 'inductive' or 'function' are considered
   920 to belong to the same "group", meaning that if at least one theorem in
   921 this group is used, the other theorems in the same group are no longer
   922 reported as unused.  Moreover, if all theorems in the group are
   923 unused, only one theorem in the group is displayed.
   924 
   925 Note that proof objects have to be switched on in order for
   926 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   927 usually the case when using Proof General with the default settings).
   928 
   929 * Authentic naming of facts disallows ad-hoc overwriting of previous
   930 theorems within the same name space.  INCOMPATIBILITY, need to remove
   931 duplicate fact bindings, or even accidental fact duplications.  Note
   932 that tools may maintain dynamically scoped facts systematically, using
   933 PureThy.add_thms_dynamic.
   934 
   935 * Command 'hide' now allows to hide from "fact" name space as well.
   936 
   937 * Eliminated destructive theorem database, simpset, claset, and
   938 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   939 update of theories within ML code.
   940 
   941 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   942 INCOMPATIBILITY, object-logics depending on former Pure require
   943 additional setup PureThy.old_appl_syntax_setup; object-logics
   944 depending on former CPure need to refer to Pure.
   945 
   946 * Commands 'use' and 'ML' are now purely functional, operating on
   947 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   948 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   949 INCOMPATIBILITY.
   950 
   951 * Command 'setup': discontinued implicit version with ML reference.
   952 
   953 * Instantiation target allows for simultaneous specification of class
   954 instance operations together with an instantiation proof.
   955 Type-checking phase allows to refer to class operations uniformly.
   956 See src/HOL/Complex/Complex.thy for an Isar example and
   957 src/HOL/Library/Eval.thy for an ML example.
   958 
   959 * Indexing of literal facts: be more serious about including only
   960 facts from the visible specification/proof context, but not the
   961 background context (locale etc.).  Affects `prop` notation and method
   962 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   963 situations.
   964 
   965 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   966 "(open)" option, which used to expose internal bound variables to the
   967 proof text.
   968 
   969 * Isar statements: removed obsolete case "rule_context".
   970 INCOMPATIBILITY, better use explicit fixes/assumes.
   971 
   972 * Locale proofs: default proof step now includes 'unfold_locales';
   973 hence 'proof' without argument may be used to unfold locale
   974 predicates.
   975 
   976 
   977 *** Document preparation ***
   978 
   979 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   980 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   981 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   982 spot); renamed link color from "darkblue" to "linkcolor" (default
   983 value unchanged, can be redefined via \definecolor); no longer sets
   984 "a4paper" option (unnecessary or even intrusive).
   985 
   986 * Antiquotation @{lemma A method} proves proposition A by the given
   987 method (either a method name or a method name plus (optional) method
   988 arguments in parentheses) and prints A just like @{prop A}.
   989 
   990 
   991 *** HOL ***
   992 
   993 * New primrec package.  Specification syntax conforms in style to
   994 definition/function/....  No separate induction rule is provided.  The
   995 "primrec" command distinguishes old-style and new-style specifications
   996 by syntax.  The former primrec package is now named OldPrimrecPackage.
   997 When adjusting theories, beware: constants stemming from new-style
   998 primrec specifications have authentic syntax.
   999 
  1000 * Metis prover is now an order of magnitude faster, and also works
  1001 with multithreading.
  1002 
  1003 * Metis: the maximum number of clauses that can be produced from a
  1004 theorem is now given by the attribute max_clauses.  Theorems that
  1005 exceed this number are ignored, with a warning printed.
  1006 
  1007 * Sledgehammer no longer produces structured proofs by default. To
  1008 enable, declare [[sledgehammer_full = true]].  Attributes
  1009 reconstruction_modulus, reconstruction_sorts renamed
  1010 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
  1011 
  1012 * Method "induct_scheme" derives user-specified induction rules
  1013 from well-founded induction and completeness of patterns. This factors
  1014 out some operations that are done internally by the function package
  1015 and makes them available separately.  See
  1016 src/HOL/ex/Induction_Scheme.thy for examples.
  1017 
  1018 * More flexible generation of measure functions for termination
  1019 proofs: Measure functions can be declared by proving a rule of the
  1020 form "is_measure f" and giving it the [measure_function] attribute.
  1021 The "is_measure" predicate is logically meaningless (always true), and
  1022 just guides the heuristic.  To find suitable measure functions, the
  1023 termination prover sets up the goal "is_measure ?f" of the appropriate
  1024 type and generates all solutions by prolog-style backwards proof using
  1025 the declared rules.
  1026 
  1027 This setup also deals with rules like 
  1028 
  1029   "is_measure f ==> is_measure (list_size f)"
  1030 
  1031 which accommodates nested datatypes that recurse through lists.
  1032 Similar rules are predeclared for products and option types.
  1033 
  1034 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
  1035 
  1036   INCOMPATIBILITIES:
  1037 
  1038   - Definitions of overloaded constants on sets have to be replaced by
  1039     definitions on => and bool.
  1040 
  1041   - Some definitions of overloaded operators on sets can now be proved
  1042     using the definitions of the operators on => and bool.  Therefore,
  1043     the following theorems have been renamed:
  1044 
  1045       subset_def   -> subset_eq
  1046       psubset_def  -> psubset_eq
  1047       set_diff_def -> set_diff_eq
  1048       Compl_def    -> Compl_eq
  1049       Sup_set_def  -> Sup_set_eq
  1050       Inf_set_def  -> Inf_set_eq
  1051       sup_set_def  -> sup_set_eq
  1052       inf_set_def  -> inf_set_eq
  1053 
  1054   - Due to the incompleteness of the HO unification algorithm, some
  1055     rules such as subst may require manual instantiation, if some of
  1056     the unknowns in the rule is a set.
  1057 
  1058   - Higher order unification and forward proofs:
  1059     The proof pattern
  1060 
  1061       have "P (S::'a set)" <...>
  1062       then have "EX S. P S" ..
  1063 
  1064     no longer works (due to the incompleteness of the HO unification
  1065     algorithm) and must be replaced by the pattern
  1066 
  1067       have "EX S. P S"
  1068       proof
  1069         show "P S" <...>
  1070       qed
  1071 
  1072   - Calculational reasoning with subst (or similar rules):
  1073     The proof pattern
  1074 
  1075       have "P (S::'a set)" <...>
  1076       also have "S = T" <...>
  1077       finally have "P T" .
  1078 
  1079     no longer works (for similar reasons as the previous example) and
  1080     must be replaced by something like
  1081 
  1082       have "P (S::'a set)" <...>
  1083       moreover have "S = T" <...>
  1084       ultimately have "P T" by simp
  1085 
  1086   - Tactics or packages written in ML code:
  1087     Code performing pattern matching on types via
  1088 
  1089       Type ("set", [T]) => ...
  1090 
  1091     must be rewritten. Moreover, functions like strip_type or
  1092     binder_types no longer return the right value when applied to a
  1093     type of the form
  1094 
  1095       T1 => ... => Tn => U => bool
  1096 
  1097     rather than
  1098 
  1099       T1 => ... => Tn => U set
  1100 
  1101 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1102 Wellfounded_Relations to theory Wellfounded.
  1103 
  1104 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1105 
  1106 * Class finite no longer treats UNIV as class parameter.  Use class
  1107 enum from theory Library/Enum instead to achieve a similar effect.
  1108 INCOMPATIBILITY.
  1109 
  1110 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1111 and "Cons".  INCOMPATIBILITY.
  1112 
  1113 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1114 Potential INCOMPATIBILITY.
  1115 
  1116 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1117 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1118 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1119 
  1120 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1121 the same name in theory Orderings:
  1122 
  1123   less_trans
  1124   less_linear
  1125   le_imp_less_or_eq
  1126   le_less_trans
  1127   less_le_trans
  1128   less_not_sym
  1129   less_asym
  1130 
  1131 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1132 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1133 and different variable names.
  1134 
  1135 * Library/Option_ord.thy: Canonical order on option type.
  1136 
  1137 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1138 finite maps.
  1139 
  1140 * Library/Countable.thy: Type class for countable types.
  1141 
  1142 * Theory Int: The representation of numerals has changed.  The infix
  1143 operator BIT and the bit datatype with constructors B0 and B1 have
  1144 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1145 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1146 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1147 accordingly.
  1148 
  1149 * Theory Nat: definition of <= and < on natural numbers no longer
  1150 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1151 le_def and less_def have disappeared.  Consider lemmas not_less
  1152 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1153 
  1154 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1155 (whose purpose mainly is for various fold_set functionals) have been
  1156 abandoned in favor of the existing algebraic classes
  1157 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1158 lower_semilattice (resp. upper_semilattice) and linorder.
  1159 INCOMPATIBILITY.
  1160 
  1161 * Theory Transitive_Closure: induct and cases rules now declare proper
  1162 case_names ("base" and "step").  INCOMPATIBILITY.
  1163 
  1164 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1165 lattices.  The form set-specific version is available as
  1166 Inductive.lfp_ordinal_induct_set.
  1167 
  1168 * Renamed theorems "power.simps" to "power_int.simps".
  1169 INCOMPATIBILITY.
  1170 
  1171 * Class semiring_div provides basic abstract properties of semirings
  1172 with division and modulo operations.  Subsumes former class dvd_mod.
  1173 
  1174 * Merged theories IntDef, Numeral and IntArith into unified theory
  1175 Int.  INCOMPATIBILITY.
  1176 
  1177 * Theory Library/Code_Index: type "index" now represents natural
  1178 numbers rather than integers.  INCOMPATIBILITY.
  1179 
  1180 * New class "uminus" with operation "uminus" (split of from class
  1181 "minus" which now only has operation "minus", binary).
  1182 INCOMPATIBILITY.
  1183 
  1184 * Constants "card", "internal_split", "option_map" now with authentic
  1185 syntax.  INCOMPATIBILITY.
  1186 
  1187 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1188 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1189 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1190 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1191 Sup_set_def, le_def, less_def, option_map_def now with object
  1192 equality.  INCOMPATIBILITY.
  1193 
  1194 * Records. Removed K_record, and replaced it by pure lambda term
  1195 %x. c. The simplifier setup is now more robust against eta expansion.
  1196 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1197 
  1198 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1199 
  1200 * Library/ListVector: new theory of arithmetic vector operations.
  1201 
  1202 * Library/Order_Relation: new theory of various orderings as sets of
  1203 pairs.  Defines preorders, partial orders, linear orders and
  1204 well-orders on sets and on types.
  1205 
  1206 
  1207 *** ZF ***
  1208 
  1209 * Renamed some theories to allow to loading both ZF and HOL in the
  1210 same session:
  1211 
  1212   Datatype  -> Datatype_ZF
  1213   Inductive -> Inductive_ZF
  1214   Int       -> Int_ZF
  1215   IntDiv    -> IntDiv_ZF
  1216   Nat       -> Nat_ZF
  1217   List      -> List_ZF
  1218   Main      -> Main_ZF
  1219 
  1220 INCOMPATIBILITY: ZF theories that import individual theories below
  1221 Main might need to be adapted.  Regular theory Main is still
  1222 available, as trivial extension of Main_ZF.
  1223 
  1224 
  1225 *** ML ***
  1226 
  1227 * ML within Isar: antiquotation @{const name} or @{const
  1228 name(typargs)} produces statically-checked Const term.
  1229 
  1230 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1231 (of the same name).  Removed obsolete print command.
  1232 
  1233 * Removed obsolete "use_legacy_bindings" function.
  1234 
  1235 * The ``print mode'' is now a thread-local value derived from a global
  1236 template (the former print_mode reference), thus access becomes
  1237 non-critical.  The global print_mode reference is for session
  1238 management only; user-code should use print_mode_value,
  1239 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1240 
  1241 * Functions system/system_out provide a robust way to invoke external
  1242 shell commands, with propagation of interrupts (requires Poly/ML
  1243 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1244 
  1245 
  1246 *** System ***
  1247 
  1248 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1249 in accordance with Proof General 3.7, which prefers GNU emacs.
  1250 
  1251 * isatool tty runs Isabelle process with plain tty interaction;
  1252 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1253 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1254 
  1255 * isatool browser now works with Cygwin as well, using general
  1256 "javapath" function defined in Isabelle process environment.
  1257 
  1258 * YXML notation provides a simple and efficient alternative to
  1259 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1260 isatool yxml as described in the Isabelle system manual.
  1261 
  1262 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1263 provides general wrapper for managing an Isabelle process in a robust
  1264 fashion, with ``cooked'' output from stdin/stderr.
  1265 
  1266 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1267 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1268 
  1269 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1270 way of changing the user's settings is via
  1271 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1272 script.
  1273 
  1274 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1275 cores of the underlying machine, which is a good starting point for
  1276 optimal performance tuning.  The corresponding usedir option -M allows
  1277 "max" as an alias for "0".  WARNING: does not work on certain versions
  1278 of Mac OS (with Poly/ML 5.1).
  1279 
  1280 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1281 adverse effect of Isabelle flooding interactive front-ends (notably
  1282 ProofGeneral / XEmacs).
  1283 
  1284 
  1285 
  1286 New in Isabelle2007 (November 2007)
  1287 -----------------------------------
  1288 
  1289 *** General ***
  1290 
  1291 * More uniform information about legacy features, notably a
  1292 warning/error of "Legacy feature: ...", depending on the state of the
  1293 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1294 legacy features will disappear eventually.
  1295 
  1296 * Theory syntax: the header format ``theory A = B + C:'' has been
  1297 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1298 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1299 
  1300 * Theory syntax: the old non-Isar theory file format has been
  1301 discontinued altogether.  Note that ML proof scripts may still be used
  1302 with Isar theories; migration is usually quite simple with the ML
  1303 function use_legacy_bindings.  INCOMPATIBILITY.
  1304 
  1305 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1306 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1307 quotes.
  1308 
  1309 * Theory loader: be more serious about observing the static theory
  1310 header specifications (including optional directories), but not the
  1311 accidental file locations of previously successful loads.  The strict
  1312 update policy of former update_thy is now already performed by
  1313 use_thy, so the former has been removed; use_thys updates several
  1314 theories simultaneously, just as 'imports' within a theory header
  1315 specification, but without merging the results.  Potential
  1316 INCOMPATIBILITY: may need to refine theory headers and commands
  1317 ROOT.ML which depend on load order.
  1318 
  1319 * Theory loader: optional support for content-based file
  1320 identification, instead of the traditional scheme of full physical
  1321 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1322 (cf. the system manual).  The new scheme allows to work with
  1323 non-finished theories in persistent session images, such that source
  1324 files may be moved later on without requiring reloads.
  1325 
  1326 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1327 file (with the same base name as the theory) are considered a legacy
  1328 feature, which will disappear eventually. Even now, the theory loader
  1329 no longer maintains dependencies on such files.
  1330 
  1331 * Syntax: the scope for resolving ambiguities via type-inference is
  1332 now limited to individual terms, instead of whole simultaneous
  1333 specifications as before. This greatly reduces the complexity of the
  1334 syntax module and improves flexibility by separating parsing and
  1335 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1336 'fixes' etc.) are required in rare situations.
  1337 
  1338 * Syntax: constants introduced by new-style packages ('definition',
  1339 'abbreviation' etc.) are passed through the syntax module in
  1340 ``authentic mode''. This means that associated mixfix annotations
  1341 really stick to such constants, independently of potential name space
  1342 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1343 trees are represented slightly differently, may need to adapt syntax
  1344 translations accordingly. Use CONST marker in 'translations' and
  1345 @{const_syntax} antiquotation in 'parse_translation' etc.
  1346 
  1347 * Legacy goal package: reduced interface to the bare minimum required
  1348 to keep existing proof scripts running.  Most other user-level
  1349 functions are now part of the OldGoals structure, which is *not* open
  1350 by default (consider isatool expandshort before open OldGoals).
  1351 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1352 these tend to cause confusion about the actual goal (!) context being
  1353 used here, which is not necessarily the same as the_context().
  1354 
  1355 * Command 'find_theorems': supports "*" wild-card in "name:"
  1356 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1357 support a specific search form (see ProofGeneral/CHANGES).
  1358 
  1359 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1360 by default, which means that "prems" (and also "fixed variables") are
  1361 suppressed from proof state output.  Note that the ProofGeneral
  1362 settings mechanism allows to change and save options persistently, but
  1363 older versions of Isabelle will fail to start up if a negative prems
  1364 limit is imposed.
  1365 
  1366 * Local theory targets may be specified by non-nested blocks of
  1367 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1368 contain definitions, theorems etc., including any derived mechanism
  1369 that has been implemented on top of these primitives.  This concept
  1370 generalizes the existing ``theorem (in ...)'' towards more versatility
  1371 and scalability.
  1372 
  1373 * Proof General interface: proper undo of final 'end' command;
  1374 discontinued Isabelle/classic mode (ML proof scripts).
  1375 
  1376 
  1377 *** Document preparation ***
  1378 
  1379 * Added antiquotation @{theory name} which prints the given name,
  1380 after checking that it refers to a valid ancestor theory in the
  1381 current context.
  1382 
  1383 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1384 check the given source text as ML type/structure, printing verbatim.
  1385 
  1386 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1387 "c args == rhs" given in the current context.  (Any number of
  1388 arguments may be given on the LHS.)
  1389 
  1390 
  1391 *** Pure ***
  1392 
  1393 * The 'class' package offers a combination of axclass and locale to
  1394 achieve Haskell-like type classes in Isabelle.  Definitions and
  1395 theorems within a class context produce both relative results (with
  1396 implicit parameters according to the locale context), and polymorphic
  1397 constants with qualified polymorphism (according to the class
  1398 context).  Within the body context of a 'class' target, a separate
  1399 syntax layer ("user space type system") takes care of converting
  1400 between global polymorphic consts and internal locale representation.
  1401 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1402 "isatool doc classes" provides a tutorial.
  1403 
  1404 * Generic code generator framework allows to generate executable
  1405 code for ML and Haskell (including Isabelle classes).  A short usage
  1406 sketch:
  1407 
  1408     internal compilation:
  1409         export_code <list of constants (term syntax)> in SML
  1410     writing SML code to a file:
  1411         export_code <list of constants (term syntax)> in SML <filename>
  1412     writing OCaml code to a file:
  1413         export_code <list of constants (term syntax)> in OCaml <filename>
  1414     writing Haskell code to a bunch of files:
  1415         export_code <list of constants (term syntax)> in Haskell <filename>
  1416 
  1417     evaluating closed propositions to True/False using code generation:
  1418         method ``eval''
  1419 
  1420 Reasonable default setup of framework in HOL.
  1421 
  1422 Theorem attributs for selecting and transforming function equations theorems:
  1423 
  1424     [code fun]:        select a theorem as function equation for a specific constant
  1425     [code fun del]:    deselect a theorem as function equation for a specific constant
  1426     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1427     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1428 
  1429 User-defined serializations (target in {SML, OCaml, Haskell}):
  1430 
  1431     code_const <and-list of constants (term syntax)>
  1432       {(target) <and-list of const target syntax>}+
  1433 
  1434     code_type <and-list of type constructors>
  1435       {(target) <and-list of type target syntax>}+
  1436 
  1437     code_instance <and-list of instances>
  1438       {(target)}+
  1439         where instance ::= <type constructor> :: <class>
  1440 
  1441     code_class <and_list of classes>
  1442       {(target) <and-list of class target syntax>}+
  1443         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1444 
  1445 code_instance and code_class only are effective to target Haskell.
  1446 
  1447 For example usage see src/HOL/ex/Codegenerator.thy and
  1448 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1449 generation from Isabelle/HOL theories is available via "isatool doc
  1450 codegen".
  1451 
  1452 * Code generator: consts in 'consts_code' Isar commands are now
  1453 referred to by usual term syntax (including optional type
  1454 annotations).
  1455 
  1456 * Command 'no_translations' removes translation rules from theory
  1457 syntax.
  1458 
  1459 * Overloaded definitions are now actually checked for acyclic
  1460 dependencies.  The overloading scheme is slightly more general than
  1461 that of Haskell98, although Isabelle does not demand an exact
  1462 correspondence to type class and instance declarations.
  1463 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1464 exotic versions of overloading -- at the discretion of the user!
  1465 
  1466 Polymorphic constants are represented via type arguments, i.e. the
  1467 instantiation that matches an instance against the most general
  1468 declaration given in the signature.  For example, with the declaration
  1469 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1470 as c(nat).  Overloading is essentially simultaneous structural
  1471 recursion over such type arguments.  Incomplete specification patterns
  1472 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1473 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1474 Command 'print_theory' outputs the normalized system of recursive
  1475 equations, see section "definitions".
  1476 
  1477 * Configuration options are maintained within the theory or proof
  1478 context (with name and type bool/int/string), providing a very simple
  1479 interface to a poor-man's version of general context data.  Tools may
  1480 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1481 these values using Config.get etc.  Users may change options via an
  1482 associated attribute of the same name.  This form of context
  1483 declaration works particularly well with commands 'declare' or
  1484 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1485 very easy to avoid global references, which would not observe Isar
  1486 toplevel undo/redo and fail to work with multithreading.
  1487 
  1488 Various global ML references of Pure and HOL have been turned into
  1489 configuration options:
  1490 
  1491   Unify.search_bound		unify_search_bound
  1492   Unify.trace_bound		unify_trace_bound
  1493   Unify.trace_simp		unify_trace_simp
  1494   Unify.trace_types		unify_trace_types
  1495   Simplifier.simp_depth_limit	simp_depth_limit
  1496   Blast.depth_limit		blast_depth_limit
  1497   DatatypeProp.dtK		datatype_distinctness_limit
  1498   fast_arith_neq_limit  	fast_arith_neq_limit
  1499   fast_arith_split_limit	fast_arith_split_limit
  1500 
  1501 * Named collections of theorems may be easily installed as context
  1502 data using the functor NamedThmsFun (see also
  1503 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1504 attributes; there is also a toplevel print command.  This facility is
  1505 just a common case of general context data, which is the preferred way
  1506 for anything more complex than just a list of facts in canonical
  1507 order.
  1508 
  1509 * Isar: command 'declaration' augments a local theory by generic
  1510 declaration functions written in ML.  This enables arbitrary content
  1511 being added to the context, depending on a morphism that tells the
  1512 difference of the original declaration context wrt. the application
  1513 context encountered later on.
  1514 
  1515 * Isar: proper interfaces for simplification procedures.  Command
  1516 'simproc_setup' declares named simprocs (with match patterns, and body
  1517 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1518 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1519 
  1520 * Isar: an extra pair of brackets around attribute declarations
  1521 abbreviates a theorem reference involving an internal dummy fact,
  1522 which will be ignored later --- only the effect of the attribute on
  1523 the background context will persist.  This form of in-place
  1524 declarations is particularly useful with commands like 'declare' and
  1525 'using', for example ``have A using [[simproc a]] by simp''.
  1526 
  1527 * Isar: method "assumption" (and implicit closing of subproofs) now
  1528 takes simple non-atomic goal assumptions into account: after applying
  1529 an assumption as a rule the resulting subgoals are solved by atomic
  1530 assumption steps.  This is particularly useful to finish 'obtain'
  1531 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1532 without referring to the original premise "!!x. P x ==> thesis" in the
  1533 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1534 more permissive.
  1535 
  1536 * Isar: implicit use of prems from the Isar proof context is
  1537 considered a legacy feature.  Common applications like ``have A .''
  1538 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1539 referencing facts explicitly here improves readability and
  1540 maintainability of proof texts.
  1541 
  1542 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1543 the obtained context from the course of reasoning!  For example:
  1544 
  1545   assume "EX x y. A x & B y"   -- "any previous fact"
  1546   then guess x and y by clarify
  1547 
  1548 This technique is potentially adventurous, depending on the facts and
  1549 proof tools being involved here.
  1550 
  1551 * Isar: known facts from the proof context may be specified as literal
  1552 propositions, using ASCII back-quote syntax.  This works wherever
  1553 named facts used to be allowed so far, in proof commands, proof
  1554 methods, attributes etc.  Literal facts are retrieved from the context
  1555 according to unification of type and term parameters.  For example,
  1556 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1557 theorems in the current context, then these are valid literal facts:
  1558 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1559 
  1560 There is also a proof method "fact" which does the same composition
  1561 for explicit goal states, e.g. the following proof texts coincide with
  1562 certain special cases of literal facts:
  1563 
  1564   have "A" by fact                 ==  note `A`
  1565   have "A ==> B" by fact           ==  note `A ==> B`
  1566   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1567   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1568 
  1569 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1570 outer syntax.  Thus symbolic identifiers may be used without
  1571 additional white space in declarations like this: ``assume *: A''.
  1572 
  1573 * Isar: 'print_facts' prints all local facts of the current context,
  1574 both named and unnamed ones.
  1575 
  1576 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1577 
  1578   def x == "t" and y == "u"
  1579 
  1580 * Isar: added command 'unfolding', which is structurally similar to
  1581 'using', but affects both the goal state and facts by unfolding given
  1582 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1583 'unfolded' attribute may be replaced by first-class proof text.
  1584 
  1585 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1586 and command 'unfolding' now all support object-level equalities
  1587 (potentially conditional).  The underlying notion of rewrite rule is
  1588 analogous to the 'rule_format' attribute, but *not* that of the
  1589 Simplifier (which is usually more generous).
  1590 
  1591 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1592 premises of a theorem by n. Useful in conjunction with drule.
  1593 
  1594 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1595 method expression within a sandbox consisting of the first N
  1596 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1597 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1598 simplifies all new goals that emerge from applying rule foo to the
  1599 originally first one.
  1600 
  1601 * Isar: schematic goals are no longer restricted to higher-order
  1602 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1603 expected.
  1604 
  1605 * Isar: the conclusion of a long theorem statement is now either
  1606 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1607 (essentially a disjunction of cases with local parameters and
  1608 assumptions).  The latter allows to express general elimination rules
  1609 adequately; in this notation common elimination rules look like this:
  1610 
  1611   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1612     assumes "EX x. P x"
  1613     obtains x where "P x"
  1614 
  1615   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1616     assumes "A & B"
  1617     obtains A and B
  1618 
  1619   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1620     assumes "A | B"
  1621     obtains
  1622       A
  1623     | B
  1624 
  1625 The subsequent classical rules even refer to the formal "thesis"
  1626 explicitly:
  1627 
  1628   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1629     obtains "~ thesis"
  1630 
  1631   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1632     obtains "thesis ==> something"
  1633 
  1634 The actual proof of an 'obtains' statement is analogous to that of the
  1635 Isar proof element 'obtain', only that there may be several cases.
  1636 Optional case names may be specified in parentheses; these will be
  1637 available both in the present proof and as annotations in the
  1638 resulting rule, for later use with the 'cases' method (cf. attribute
  1639 case_names).
  1640 
  1641 * Isar: the assumptions of a long theorem statement are available as
  1642 "assms" fact in the proof context.  This is more appropriate than the
  1643 (historical) "prems", which refers to all assumptions of the current
  1644 context, including those from the target locale, proof body etc.
  1645 
  1646 * Isar: 'print_statement' prints theorems from the current theory or
  1647 proof context in long statement form, according to the syntax of a
  1648 top-level lemma.
  1649 
  1650 * Isar: 'obtain' takes an optional case name for the local context
  1651 introduction rule (default "that").
  1652 
  1653 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1654 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1655 to occur.
  1656 
  1657 * Pure: syntax "CONST name" produces a fully internalized constant
  1658 according to the current context.  This is particularly useful for
  1659 syntax translations that should refer to internal constant
  1660 representations independently of name spaces.
  1661 
  1662 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1663 instead of "FOO ". This allows multiple binder declarations to coexist
  1664 in the same context.  INCOMPATIBILITY.
  1665 
  1666 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1667 primitive that also works in a locale context (both for constants and
  1668 fixed variables). Type declaration and internal syntactic representation
  1669 of given constants retrieved from the context. Likewise, the
  1670 'no_notation' command allows to remove given syntax annotations from the
  1671 current context.
  1672 
  1673 * Isar/locales: new derived specification elements 'axiomatization',
  1674 'definition', 'abbreviation', which support type-inference, admit
  1675 object-level specifications (equality, equivalence).  See also the
  1676 isar-ref manual.  Examples:
  1677 
  1678   axiomatization
  1679     eq  (infix "===" 50) where
  1680     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1681 
  1682   definition "f x y = x + y + 1"
  1683   definition g where "g x = f x x"
  1684 
  1685   abbreviation
  1686     neq  (infix "=!=" 50) where
  1687     "x =!= y == ~ (x === y)"
  1688 
  1689 These specifications may be also used in a locale context.  Then the
  1690 constants being introduced depend on certain fixed parameters, and the
  1691 constant name is qualified by the locale base name.  An internal
  1692 abbreviation takes care for convenient input and output, making the
  1693 parameters implicit and using the original short name.  See also
  1694 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1695 entities from a monomorphic theory.
  1696 
  1697 Presently, abbreviations are only available 'in' a target locale, but
  1698 not inherited by general import expressions.  Also note that
  1699 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1700 'translations' in common applications.  The "no_abbrevs" print mode
  1701 prevents folding of abbreviations in term output.
  1702 
  1703 Concrete syntax is attached to specified constants in internal form,
  1704 independently of name spaces.  The parse tree representation is
  1705 slightly different -- use 'notation' instead of raw 'syntax', and
  1706 'translations' with explicit "CONST" markup to accommodate this.
  1707 
  1708 * Pure/Isar: unified syntax for new-style specification mechanisms
  1709 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1710 full type inference and dummy patterns ("_").  For example:
  1711 
  1712   definition "K x _ = x"
  1713 
  1714   inductive conj for A B
  1715   where "A ==> B ==> conj A B"
  1716 
  1717 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1718 the current context.  Print mode "no_abbrevs" prevents inversion of
  1719 abbreviations on output.
  1720 
  1721 * Isar/locales: improved parameter handling: use of locales "var" and
  1722 "struct" no longer necessary; - parameter renamings are no longer
  1723 required to be injective.  For example, this allows to define
  1724 endomorphisms as locale endom = homom mult mult h.
  1725 
  1726 * Isar/locales: changed the way locales with predicates are defined.
  1727 Instead of accumulating the specification, the imported expression is
  1728 now an interpretation.  INCOMPATIBILITY: different normal form of
  1729 locale expressions.  In particular, in interpretations of locales with
  1730 predicates, goals repesenting already interpreted fragments are not
  1731 removed automatically.  Use methods `intro_locales' and
  1732 `unfold_locales'; see below.
  1733 
  1734 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1735 provide backward reasoning on locales predicates.  The methods are
  1736 aware of interpretations and discharge corresponding goals.
  1737 `intro_locales' is less aggressive then `unfold_locales' and does not
  1738 unfold predicates to assumptions.
  1739 
  1740 * Isar/locales: the order in which locale fragments are accumulated
  1741 has changed.  This enables to override declarations from fragments due
  1742 to interpretations -- for example, unwanted simp rules.
  1743 
  1744 * Isar/locales: interpretation in theories and proof contexts has been
  1745 extended.  One may now specify (and prove) equations, which are
  1746 unfolded in interpreted theorems.  This is useful for replacing
  1747 defined concepts (constants depending on locale parameters) by
  1748 concepts already existing in the target context.  Example:
  1749 
  1750   interpretation partial_order ["op <= :: [int, int] => bool"]
  1751     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1752 
  1753 Typically, the constant `partial_order.less' is created by a
  1754 definition specification element in the context of locale
  1755 partial_order.
  1756 
  1757 * Method "induct": improved internal context management to support
  1758 local fixes and defines on-the-fly. Thus explicit meta-level
  1759 connectives !!  and ==> are rarely required anymore in inductive goals
  1760 (using object-logic connectives for this purpose has been long
  1761 obsolete anyway). Common proof patterns are explained in
  1762 src/HOL/Induct/Common_Patterns.thy, see also
  1763 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1764 examples.
  1765 
  1766 * Method "induct": improved handling of simultaneous goals. Instead of
  1767 introducing object-level conjunction, the statement is now split into
  1768 several conclusions, while the corresponding symbolic cases are nested
  1769 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1770 see src/HOL/Induct/Common_Patterns.thy, for example.
  1771 
  1772 * Method "induct": mutual induction rules are now specified as a list
  1773 of rule sharing the same induction cases. HOL packages usually provide
  1774 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1775 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1776 mutual induction rules differently, i.e. like this:
  1777 
  1778   (induct rule: foo_bar.inducts)
  1779   (induct set: foo bar)
  1780   (induct pred: foo bar)
  1781   (induct type: foo bar)
  1782 
  1783 The ML function ProjectRule.projections turns old-style rules into the
  1784 new format.
  1785 
  1786 * Method "coinduct": dual of induction, see
  1787 src/HOL/Library/Coinductive_List.thy for various examples.
  1788 
  1789 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1790 considered a legacy feature.
  1791 
  1792 * Attribute "symmetric" produces result with standardized schematic
  1793 variables (index 0).  Potential INCOMPATIBILITY.
  1794 
  1795 * Simplifier: by default the simplifier trace only shows top level
  1796 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1797 default. Thus there is less danger of being flooded by the trace. The
  1798 trace indicates where parts have been suppressed.
  1799   
  1800 * Provers/classical: removed obsolete classical version of elim_format
  1801 attribute; classical elim/dest rules are now treated uniformly when
  1802 manipulating the claset.
  1803 
  1804 * Provers/classical: stricter checks to ensure that supplied intro,
  1805 dest and elim rules are well-formed; dest and elim rules must have at
  1806 least one premise.
  1807 
  1808 * Provers/classical: attributes dest/elim/intro take an optional
  1809 weight argument for the rule (just as the Pure versions).  Weights are
  1810 ignored by automated tools, but determine the search order of single
  1811 rule steps.
  1812 
  1813 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1814 where the body does not mention the bound variable.  Note that dummy
  1815 patterns implicitly depend on their context of bounds, which makes
  1816 "{_. _}" match any set comprehension as expected.  Potential
  1817 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1818 constant "_idtdummy" in the binding position.
  1819 
  1820 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1821 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1822 for example "A -> B" => "Pi A (%_. B)".
  1823 
  1824 * Pure: 'class_deps' command visualizes the subclass relation, using
  1825 the graph browser tool.
  1826 
  1827 * Pure: 'print_theory' now suppresses certain internal declarations by
  1828 default; use '!' option for full details.
  1829 
  1830 
  1831 *** HOL ***
  1832 
  1833 * Method "metis" proves goals by applying the Metis general-purpose
  1834 resolution prover (see also http://gilith.com/software/metis/).
  1835 Examples are in the directory MetisExamples.  WARNING: the
  1836 Isabelle/HOL-Metis integration does not yet work properly with
  1837 multi-threading.
  1838   
  1839 * Command 'sledgehammer' invokes external automatic theorem provers as
  1840 background processes.  It generates calls to the "metis" method if
  1841 successful. These can be pasted into the proof.  Users do not have to
  1842 wait for the automatic provers to return.  WARNING: does not really
  1843 work with multi-threading.
  1844 
  1845 * New "auto_quickcheck" feature tests outermost goal statements for
  1846 potential counter-examples.  Controlled by ML references
  1847 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1848 5000 milliseconds).  Fails silently if statements is outside of
  1849 executable fragment, or any other codgenerator problem occurs.
  1850 
  1851 * New constant "undefined" with axiom "undefined x = undefined".
  1852 
  1853 * Added class "HOL.eq", allowing for code generation with polymorphic
  1854 equality.
  1855 
  1856 * Some renaming of class constants due to canonical name prefixing in
  1857 the new 'class' package:
  1858 
  1859     HOL.abs ~> HOL.abs_class.abs
  1860     HOL.divide ~> HOL.divide_class.divide
  1861     0 ~> HOL.zero_class.zero
  1862     1 ~> HOL.one_class.one
  1863     op + ~> HOL.plus_class.plus
  1864     op - ~> HOL.minus_class.minus
  1865     uminus ~> HOL.minus_class.uminus
  1866     op * ~> HOL.times_class.times
  1867     op < ~> HOL.ord_class.less
  1868     op <= > HOL.ord_class.less_eq
  1869     Nat.power ~> Power.power_class.power
  1870     Nat.size ~> Nat.size_class.size
  1871     Numeral.number_of ~> Numeral.number_class.number_of
  1872     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1873     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1874     Orderings.min ~> Orderings.ord_class.min
  1875     Orderings.max ~> Orderings.ord_class.max
  1876     Divides.op div ~> Divides.div_class.div
  1877     Divides.op mod ~> Divides.div_class.mod
  1878     Divides.op dvd ~> Divides.div_class.dvd
  1879 
  1880 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1881 
  1882 a) User-defined constants using any of the names "plus", "minus",
  1883 "times", "less" or "less_eq". The standard syntax translations for
  1884 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1885 names.
  1886 
  1887 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1888 INCOMPATIBILITY: use more specific names.
  1889 
  1890 c) Permutative equations (e.g. "a + b = b + a")
  1891 Since the change of names also changes the order of terms, permutative
  1892 rewrite rules may get applied in a different order. Experience shows
  1893 that this is rarely the case (only two adaptions in the whole Isabelle
  1894 distribution).  INCOMPATIBILITY: rewrite proofs
  1895 
  1896 d) ML code directly refering to constant names
  1897 This in general only affects hand-written proof tactics, simprocs and
  1898 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1899 Consider using @{const_name} antiquotation.
  1900 
  1901 * New class "default" with associated constant "default".
  1902 
  1903 * Function "sgn" is now overloaded and available on int, real, complex
  1904 (and other numeric types), using class "sgn".  Two possible defs of
  1905 sgn are given as equational assumptions in the classes sgn_if and
  1906 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1907 INCOMPATIBILITY.
  1908 
  1909 * Locale "partial_order" now unified with class "order" (cf. theory
  1910 Orderings), added parameter "less".  INCOMPATIBILITY.
  1911 
  1912 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1913 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1914 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1915 
  1916 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1917 changed order of proof goals in instance proofs.
  1918 
  1919 * The transitivity reasoner for partial and linear orders is set up
  1920 for classes "order" and "linorder".  Instances of the reasoner are available
  1921 in all contexts importing or interpreting the corresponding locales.
  1922 Method "order" invokes the reasoner separately; the reasoner
  1923 is also integrated with the Simplifier as a solver.  Diagnostic
  1924 command 'print_orders' shows the available instances of the reasoner
  1925 in the current context.
  1926 
  1927 * Localized monotonicity predicate in theory "Orderings"; integrated
  1928 lemmas max_of_mono and min_of_mono with this predicate.
  1929 INCOMPATIBILITY.
  1930 
  1931 * Formulation of theorem "dense" changed slightly due to integration
  1932 with new class dense_linear_order.
  1933 
  1934 * Uniform lattice theory development in HOL.
  1935 
  1936     constants "meet" and "join" now named "inf" and "sup"
  1937     constant "Meet" now named "Inf"
  1938 
  1939     classes "meet_semilorder" and "join_semilorder" now named
  1940       "lower_semilattice" and "upper_semilattice"
  1941     class "lorder" now named "lattice"
  1942     class "comp_lat" now named "complete_lattice"
  1943 
  1944     Instantiation of lattice classes allows explicit definitions
  1945     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1946 
  1947   INCOMPATIBILITY.  Theorem renames:
  1948 
  1949     meet_left_le            ~> inf_le1
  1950     meet_right_le           ~> inf_le2
  1951     join_left_le            ~> sup_ge1
  1952     join_right_le           ~> sup_ge2
  1953     meet_join_le            ~> inf_sup_ord
  1954     le_meetI                ~> le_infI
  1955     join_leI                ~> le_supI
  1956     le_meet                 ~> le_inf_iff
  1957     le_join                 ~> ge_sup_conv
  1958     meet_idempotent         ~> inf_idem
  1959     join_idempotent         ~> sup_idem
  1960     meet_comm               ~> inf_commute
  1961     join_comm               ~> sup_commute
  1962     meet_leI1               ~> le_infI1
  1963     meet_leI2               ~> le_infI2
  1964     le_joinI1               ~> le_supI1
  1965     le_joinI2               ~> le_supI2
  1966     meet_assoc              ~> inf_assoc
  1967     join_assoc              ~> sup_assoc
  1968     meet_left_comm          ~> inf_left_commute
  1969     meet_left_idempotent    ~> inf_left_idem
  1970     join_left_comm          ~> sup_left_commute
  1971     join_left_idempotent    ~> sup_left_idem
  1972     meet_aci                ~> inf_aci
  1973     join_aci                ~> sup_aci
  1974     le_def_meet             ~> le_iff_inf
  1975     le_def_join             ~> le_iff_sup
  1976     join_absorp2            ~> sup_absorb2
  1977     join_absorp1            ~> sup_absorb1
  1978     meet_absorp1            ~> inf_absorb1
  1979     meet_absorp2            ~> inf_absorb2
  1980     meet_join_absorp        ~> inf_sup_absorb
  1981     join_meet_absorp        ~> sup_inf_absorb
  1982     distrib_join_le         ~> distrib_sup_le
  1983     distrib_meet_le         ~> distrib_inf_le
  1984 
  1985     add_meet_distrib_left   ~> add_inf_distrib_left
  1986     add_join_distrib_left   ~> add_sup_distrib_left
  1987     is_join_neg_meet        ~> is_join_neg_inf
  1988     is_meet_neg_join        ~> is_meet_neg_sup
  1989     add_meet_distrib_right  ~> add_inf_distrib_right
  1990     add_join_distrib_right  ~> add_sup_distrib_right
  1991     add_meet_join_distribs  ~> add_sup_inf_distribs
  1992     join_eq_neg_meet        ~> sup_eq_neg_inf
  1993     meet_eq_neg_join        ~> inf_eq_neg_sup
  1994     add_eq_meet_join        ~> add_eq_inf_sup
  1995     meet_0_imp_0            ~> inf_0_imp_0
  1996     join_0_imp_0            ~> sup_0_imp_0
  1997     meet_0_eq_0             ~> inf_0_eq_0
  1998     join_0_eq_0             ~> sup_0_eq_0
  1999     neg_meet_eq_join        ~> neg_inf_eq_sup
  2000     neg_join_eq_meet        ~> neg_sup_eq_inf
  2001     join_eq_if              ~> sup_eq_if
  2002 
  2003     mono_meet               ~> mono_inf
  2004     mono_join               ~> mono_sup
  2005     meet_bool_eq            ~> inf_bool_eq
  2006     join_bool_eq            ~> sup_bool_eq
  2007     meet_fun_eq             ~> inf_fun_eq
  2008     join_fun_eq             ~> sup_fun_eq
  2009     meet_set_eq             ~> inf_set_eq
  2010     join_set_eq             ~> sup_set_eq
  2011     meet1_iff               ~> inf1_iff
  2012     meet2_iff               ~> inf2_iff
  2013     meet1I                  ~> inf1I
  2014     meet2I                  ~> inf2I
  2015     meet1D1                 ~> inf1D1
  2016     meet2D1                 ~> inf2D1
  2017     meet1D2                 ~> inf1D2
  2018     meet2D2                 ~> inf2D2
  2019     meet1E                  ~> inf1E
  2020     meet2E                  ~> inf2E
  2021     join1_iff               ~> sup1_iff
  2022     join2_iff               ~> sup2_iff
  2023     join1I1                 ~> sup1I1
  2024     join2I1                 ~> sup2I1
  2025     join1I1                 ~> sup1I1
  2026     join2I2                 ~> sup1I2
  2027     join1CI                 ~> sup1CI
  2028     join2CI                 ~> sup2CI
  2029     join1E                  ~> sup1E
  2030     join2E                  ~> sup2E
  2031 
  2032     is_meet_Meet            ~> is_meet_Inf
  2033     Meet_bool_def           ~> Inf_bool_def
  2034     Meet_fun_def            ~> Inf_fun_def
  2035     Meet_greatest           ~> Inf_greatest
  2036     Meet_lower              ~> Inf_lower
  2037     Meet_set_def            ~> Inf_set_def
  2038 
  2039     Sup_def                 ~> Sup_Inf
  2040     Sup_bool_eq             ~> Sup_bool_def
  2041     Sup_fun_eq              ~> Sup_fun_def
  2042     Sup_set_eq              ~> Sup_set_def
  2043 
  2044     listsp_meetI            ~> listsp_infI
  2045     listsp_meet_eq          ~> listsp_inf_eq
  2046 
  2047     meet_min                ~> inf_min
  2048     join_max                ~> sup_max
  2049 
  2050 * Added syntactic class "size"; overloaded constant "size" now has
  2051 type "'a::size ==> bool"
  2052 
  2053 * Internal reorganisation of `size' of datatypes: size theorems
  2054 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2055 simplification rules by default!); theorems "prod.size" now named
  2056 "*.size".
  2057 
  2058 * Class "div" now inherits from class "times" rather than "type".
  2059 INCOMPATIBILITY.
  2060 
  2061 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2062 Linorder etc.  have disappeared; operations defined in terms of
  2063 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2064 
  2065 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2066 
  2067 * HOL-Word: New extensive library and type for generic, fixed size
  2068 machine words, with arithemtic, bit-wise, shifting and rotating
  2069 operations, reflection into int, nat, and bool lists, automation for
  2070 linear arithmetic (by automatic reflection into nat or int), including
  2071 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2072 arithmetic type classes, supporting automatic simplification of
  2073 numerals on all operations.
  2074 
  2075 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2076 
  2077 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2078 
  2079 * Code generator library theories:
  2080   - Code_Integer represents HOL integers by big integer literals in target
  2081     languages.
  2082   - Code_Char represents HOL characters by character literals in target
  2083     languages.
  2084   - Code_Char_chr like Code_Char, but also offers treatment of character
  2085     codes; includes Code_Integer.
  2086   - Executable_Set allows to generate code for finite sets using lists.
  2087   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2088     denominator).
  2089   - Executable_Real implements a subset of real numbers, namly those
  2090     representable by rational numbers.
  2091   - Efficient_Nat implements natural numbers by integers, which in general will
  2092     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2093     includes Code_Integer.
  2094   - Code_Index provides an additional datatype index which is mapped to
  2095     target-language built-in integers.
  2096   - Code_Message provides an additional datatype message_string which is isomorphic to
  2097     strings; messages are mapped to target-language strings.
  2098 
  2099 * New package for inductive predicates
  2100 
  2101   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2102 
  2103     inductive
  2104       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2105       for z_1 :: U_1 and ... and z_n :: U_m
  2106     where
  2107       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2108     | ...
  2109 
  2110   with full support for type-inference, rather than
  2111 
  2112     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2113 
  2114     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2115     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2116 
  2117     inductive "s z_1 ... z_m"
  2118     intros
  2119       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2120       ...
  2121 
  2122   For backward compatibility, there is a wrapper allowing inductive
  2123   sets to be defined with the new package via
  2124 
  2125     inductive_set
  2126       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2127       for z_1 :: U_1 and ... and z_n :: U_m
  2128     where
  2129       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2130     | ...
  2131 
  2132   or
  2133 
  2134     inductive_set
  2135       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2136       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2137       for z_1 :: U_1 and ... and z_n :: U_m
  2138     where
  2139       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2140     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2141     | ...
  2142 
  2143   if the additional syntax "p ..." is required.
  2144 
  2145   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2146   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2147 
  2148   INCOMPATIBILITIES:
  2149 
  2150   - Since declaration and definition of inductive sets or predicates
  2151     is no longer separated, abbreviations involving the newly
  2152     introduced sets or predicates must be specified together with the
  2153     introduction rules after the 'where' keyword (see above), rather
  2154     than before the actual inductive definition.
  2155 
  2156   - The variables in induction and elimination rules are now
  2157     quantified in the order of their occurrence in the introduction
  2158     rules, rather than in alphabetical order. Since this may break
  2159     some proofs, these proofs either have to be repaired, e.g. by
  2160     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2161     statements of the form
  2162 
  2163       case (rule_i a_i_1 ... a_i_{k_i})
  2164 
  2165     or the old order of quantification has to be restored by explicitly adding
  2166     meta-level quantifiers in the introduction rules, i.e.
  2167 
  2168       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2169 
  2170   - The format of the elimination rules is now
  2171 
  2172       p z_1 ... z_m x_1 ... x_n ==>
  2173         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2174         ==> ... ==> P
  2175 
  2176     for predicates and
  2177 
  2178       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2179         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2180         ==> ... ==> P
  2181 
  2182     for sets rather than
  2183 
  2184       x : s z_1 ... z_m ==>
  2185         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2186         ==> ... ==> P
  2187 
  2188     This may require terms in goals to be expanded to n-tuples
  2189     (e.g. using case_tac or simplification with the split_paired_all
  2190     rule) before the above elimination rule is applicable.
  2191 
  2192   - The elimination or case analysis rules for (mutually) inductive
  2193     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2194     list of rules "p_1_..._p_k.elims" is no longer available.
  2195 
  2196 * New package "function"/"fun" for general recursive functions,
  2197 supporting mutual and nested recursion, definitions in local contexts,
  2198 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2199 for small examples, and the separate tutorial on the function
  2200 package. The old recdef "package" is still available as before, but
  2201 users are encouraged to use the new package.
  2202 
  2203 * Method "lexicographic_order" automatically synthesizes termination
  2204 relations as lexicographic combinations of size measures. 
  2205 
  2206 * Case-expressions allow arbitrary constructor-patterns (including
  2207 "_") and take their order into account, like in functional
  2208 programming.  Internally, this is translated into nested
  2209 case-expressions; missing cases are added and mapped to the predefined
  2210 constant "undefined". In complicated cases printing may no longer show
  2211 the original input but the internal form. Lambda-abstractions allow
  2212 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2213 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2214 variable.
  2215 
  2216 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2217 is an abbreviation for "of_nat :: nat => int". The simplification
  2218 rules for "of_nat" have been changed to work like "int" did
  2219 previously.  Potential INCOMPATIBILITY:
  2220   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2221   - of_nat_diff and of_nat_mult are no longer default simp rules
  2222 
  2223 * Method "algebra" solves polynomial equations over (semi)rings using
  2224 Groebner bases. The (semi)ring structure is defined by locales and the
  2225 tool setup depends on that generic context. Installing the method for
  2226 a specific type involves instantiating the locale and possibly adding
  2227 declarations for computation on the coefficients.  The method is
  2228 already instantiated for natural numbers and for the axiomatic class
  2229 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2230 CALCULEMUS 2007 for the general principles underlying this
  2231 architecture of context-aware proof-tools.
  2232 
  2233 * Method "ferrack" implements quantifier elimination over
  2234 special-purpose dense linear orders using locales (analogous to
  2235 "algebra"). The method is already installed for class
  2236 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2237 rat, etc.
  2238 
  2239 * Former constant "List.op @" now named "List.append".  Use ML
  2240 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2241 circumvent possible incompatibilities when working on ML level.
  2242 
  2243 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2244 
  2245 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2246 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2247 
  2248 * New syntax for Haskell-like list comprehension (input only), eg.
  2249 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2250 
  2251 * The special syntax for function "filter" has changed from [x :
  2252 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2253 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2254 
  2255 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2256 defined on nat only, as an abbreviation for [a..<Suc b]
  2257 INCOMPATIBILITY.
  2258 
  2259 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2260 
  2261 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2262 
  2263 * New lemma collection field_simps (an extension of ring_simps) for
  2264 manipulating (in)equations involving division. Multiplies with all
  2265 denominators that can be proved to be non-zero (in equations) or
  2266 positive/negative (in inequations).
  2267 
  2268 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2269 have been improved and renamed to ring_simps, group_simps and
  2270 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2271 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2272 
  2273 * Theory Library/Commutative_Ring: switched from recdef to function
  2274 package; constants add, mul, pow now curried.  Infix syntax for
  2275 algebraic operations.
  2276 
  2277 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2278 INCOMPATIBILITY.
  2279 
  2280 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2281 INCOMPATIBILITY.
  2282 
  2283 * HOL/records: generalised field-update to take a function on the
  2284 field rather than the new value: r(|A := x|) is translated to A_update
  2285 (K x) r The K-combinator that is internally used is called K_record.
  2286 INCOMPATIBILITY: Usage of the plain update functions has to be
  2287 adapted.
  2288  
  2289 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2290 * x = 0, which are required for a semiring.  Richer structures do not
  2291 inherit from semiring_0 anymore, because this property is a theorem
  2292 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2293 there is more to prove, but this is mostly trivial.
  2294 
  2295 * Class "recpower" is generalized to arbitrary monoids, not just
  2296 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2297 commutativity or semiring properties additionally.
  2298 
  2299 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2300 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2301 better use 'abbreviation'.
  2302 
  2303 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2304 
  2305 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2306 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2307 significant changes for setting up numeral syntax for types:
  2308   - New constants Numeral.pred and Numeral.succ instead
  2309       of former Numeral.bin_pred and Numeral.bin_succ.
  2310   - Use integer operations instead of bin_add, bin_mult and so on.
  2311   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2312   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2313 
  2314 See src/HOL/Integ/IntArith.thy for an example setup.
  2315 
  2316 * Command 'normal_form' computes the normal form of a term that may
  2317 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2318 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2319 heavy-duty computations because the functions are compiled to ML
  2320 first.  Correspondingly, a method "normalization" is provided.  See
  2321 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2322 
  2323 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2324 25 like -->); output depends on the "iff" print_mode, the default is
  2325 "A = B" (with priority 50).
  2326 
  2327 * Relations less (<) and less_eq (<=) are also available on type bool.
  2328 Modified syntax to disallow nesting without explicit parentheses,
  2329 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2330 INCOMPATIBILITY.
  2331 
  2332 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2333 
  2334 * Relation composition operator "op O" now has precedence 75 and binds
  2335 stronger than union and intersection. INCOMPATIBILITY.
  2336 
  2337 * The old set interval syntax "{m..n(}" (and relatives) has been
  2338 removed.  Use "{m..<n}" (and relatives) instead.
  2339 
  2340 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2341 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2342 ``declare [[simproc del: neq]]''.
  2343 
  2344 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2345 True/False.
  2346 
  2347 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2348 
  2349 * Theorem setsum_mult renamed to setsum_right_distrib.
  2350 
  2351 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2352 ``rule'' method.
  2353 
  2354 * Reimplemented methods "sat" and "satx", with several improvements:
  2355 goals no longer need to be stated as "<prems> ==> False", equivalences
  2356 (i.e. "=" on type bool) are handled, variable names of the form
  2357 "lit_<n>" are no longer reserved, significant speedup.
  2358 
  2359 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2360 zChaff is still supported as well.
  2361 
  2362 * 'inductive' and 'datatype': provide projections of mutual rules,
  2363 bundled as foo_bar.inducts;
  2364 
  2365 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2366 Library.
  2367 
  2368 * Library: moved theory Accessible_Part to main HOL.
  2369 
  2370 * Library: added theory Coinductive_List of potentially infinite lists
  2371 as greatest fixed-point.
  2372 
  2373 * Library: added theory AssocList which implements (finite) maps as
  2374 association lists.
  2375 
  2376 * Method "evaluation" solves goals (i.e. a boolean expression)
  2377 efficiently by compiling it to ML.  The goal is "proved" (via an
  2378 oracle) if it evaluates to True.
  2379 
  2380 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2381 also when invoked by the simplifier.  This results in the Simplifier
  2382 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2383 Configuration option fast_arith_split_limit=0 recovers the old
  2384 behavior.
  2385 
  2386 * Support for hex (0x20) and binary (0b1001) numerals.
  2387 
  2388 * New method: reify eqs (t), where eqs are equations for an
  2389 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2390 parameter, computes a term s::'b and a list xs::'a list and proves the
  2391 theorem I xs s = t. This is also known as reification or quoting. The
  2392 resulting theorem is applied to the subgoal to substitute t with I xs
  2393 s.  If t is omitted, the subgoal itself is reified.
  2394 
  2395 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2396 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2397 where f is supposed to be a computable function (in the sense of code
  2398 generattion). The method uses reify to compute s and xs as above then
  2399 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2400 r and finally gets the theorem t = r, which is again applied to the
  2401 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2402 
  2403 * Reflection: Automatic reification now handels binding, an example is
  2404 available in src/HOL/ex/ReflectionEx.thy
  2405 
  2406 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2407 command 'statespace' that is similar to 'record', but introduces an
  2408 abstract specification based on the locale infrastructure instead of
  2409 HOL types.  This leads to extra flexibility in composing state spaces,
  2410 in particular multiple inheritance and renaming of components.
  2411 
  2412 
  2413 *** HOL-Complex ***
  2414 
  2415 * Hyperreal: Functions root and sqrt are now defined on negative real
  2416 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2417 Nonnegativity side conditions have been removed from many lemmas, so
  2418 that more subgoals may now be solved by simplification; potential
  2419 INCOMPATIBILITY.
  2420 
  2421 * Real: new type classes formalize real normed vector spaces and
  2422 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2423 and norm :: 'a => real.
  2424 
  2425 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2426 reals into other types. The overloaded constant Reals :: 'a set is now
  2427 defined as range of_real; potential INCOMPATIBILITY.
  2428 
  2429 * Real: proper support for ML code generation, including 'quickcheck'.
  2430 Reals are implemented as arbitrary precision rationals.
  2431 
  2432 * Hyperreal: Several constants that previously worked only for the
  2433 reals have been generalized, so they now work over arbitrary vector
  2434 spaces. Type annotations may need to be added in some cases; potential
  2435 INCOMPATIBILITY.
  2436 
  2437   Infinitesimal  :: ('a::real_normed_vector) star set
  2438   HFinite        :: ('a::real_normed_vector) star set
  2439   HInfinite      :: ('a::real_normed_vector) star set
  2440   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2441   monad          :: ('a::real_normed_vector) star => 'a star set
  2442   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2443   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2444   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2445   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2446   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2447   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2448   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2449   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2450   sgn            :: 'a::real_normed_vector => 'a
  2451   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2452 
  2453 * Complex: Some complex-specific constants are now abbreviations for
  2454 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2455 hnorm.  Other constants have been entirely removed in favor of the
  2456 polymorphic versions (INCOMPATIBILITY):
  2457 
  2458   approx        <-- capprox
  2459   HFinite       <-- CFinite
  2460   HInfinite     <-- CInfinite
  2461   Infinitesimal <-- CInfinitesimal
  2462   monad         <-- cmonad
  2463   galaxy        <-- cgalaxy
  2464   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2465   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2466   (ns)deriv     <-- (ns)cderiv
  2467 
  2468 
  2469 *** HOL-Algebra ***
  2470 
  2471 * Formalisation of ideals and the quotient construction over rings.
  2472 
  2473 * Order and lattice theory no longer based on records.
  2474 INCOMPATIBILITY.
  2475 
  2476 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2477 greatest_closed.  INCOMPATIBILITY.
  2478 
  2479 * Method algebra is now set up via an attribute.  For examples see
  2480 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2481 of algebraic structures.
  2482 
  2483 * Renamed theory CRing to Ring.
  2484 
  2485 
  2486 *** HOL-Nominal ***
  2487 
  2488 * Substantial, yet incomplete support for nominal datatypes (binding
  2489 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2490 src/HOL/Nominal/Examples.  Prospective users should consult
  2491 http://isabelle.in.tum.de/nominal/
  2492 
  2493 
  2494 *** ML ***
  2495 
  2496 * ML basics: just one true type int, which coincides with IntInf.int
  2497 (even on SML/NJ).
  2498 
  2499 * ML within Isar: antiquotations allow to embed statically-checked
  2500 formal entities in the source, referring to the context available at
  2501 compile-time.  For example:
  2502 
  2503 ML {* @{sort "{zero,one}"} *}
  2504 ML {* @{typ "'a => 'b"} *}
  2505 ML {* @{term "%x. x"} *}
  2506 ML {* @{prop "x == y"} *}
  2507 ML {* @{ctyp "'a => 'b"} *}
  2508 ML {* @{cterm "%x. x"} *}
  2509 ML {* @{cprop "x == y"} *}
  2510 ML {* @{thm asm_rl} *}
  2511 ML {* @{thms asm_rl} *}
  2512 ML {* @{type_name c} *}
  2513 ML {* @{type_syntax c} *}
  2514 ML {* @{const_name c} *}
  2515 ML {* @{const_syntax c} *}
  2516 ML {* @{context} *}
  2517 ML {* @{theory} *}
  2518 ML {* @{theory Pure} *}
  2519 ML {* @{theory_ref} *}
  2520 ML {* @{theory_ref Pure} *}
  2521 ML {* @{simpset} *}
  2522 ML {* @{claset} *}
  2523 ML {* @{clasimpset} *}
  2524 
  2525 The same works for sources being ``used'' within an Isar context.
  2526 
  2527 * ML in Isar: improved error reporting; extra verbosity with
  2528 ML_Context.trace enabled.
  2529 
  2530 * Pure/General/table.ML: the join operations now works via exceptions
  2531 DUP/SAME instead of type option. This is simpler in simple cases, and
  2532 admits slightly more efficient complex applications.
  2533 
  2534 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2535 use Context.generic instead of just theory.
  2536 
  2537 * Pure: datatype Context.generic joins theory/Proof.context and
  2538 provides some facilities for code that works in either kind of
  2539 context, notably GenericDataFun for uniform theory and proof data.
  2540 
  2541 * Pure: simplified internal attribute type, which is now always
  2542 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2543 local (Proof.context) attributes have been discontinued, while
  2544 minimizing code duplication. Thm.rule_attribute and
  2545 Thm.declaration_attribute build canonical attributes; see also structure
  2546 Context for further operations on Context.generic, notably
  2547 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2548 declarations and definitions.
  2549 
  2550 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2551 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2552 init only required for impure data. INCOMPATIBILITY: empty really need
  2553 to be empty (no dependencies on theory content!)
  2554 
  2555 * Pure/kernel: consts certification ignores sort constraints given in
  2556 signature declarations. (This information is not relevant to the
  2557 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2558 potential INCOMPATIBILITY.
  2559 
  2560 * Pure: axiomatic type classes are now purely definitional, with
  2561 explicit proofs of class axioms and super class relations performed
  2562 internally. See Pure/axclass.ML for the main internal interfaces --
  2563 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2564 AxClass.axiomatize_class/classrel/arity supersede
  2565 Sign.add_classes/classrel/arities.
  2566 
  2567 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2568 global/local versions on theory vs. Proof.context have been
  2569 discontinued; Attrib.syntax and Method.syntax have been adapted
  2570 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2571 attributes, methods, etc.
  2572 
  2573 * Pure: several functions of signature "... -> theory -> theory * ..."
  2574 have been reoriented to "... -> theory -> ... * theory" in order to
  2575 allow natural usage in combination with the ||>, ||>>, |-> and
  2576 fold_map combinators.
  2577 
  2578 * Pure: official theorem names (closed derivations) and additional
  2579 comments (tags) are now strictly separate.  Name hints -- which are
  2580 maintained as tags -- may be attached any time without affecting the
  2581 derivation.
  2582 
  2583 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2584 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2585 achieve the old behaviour.
  2586 
  2587 * Pure: the "Goal" constant is now called "prop", supporting a
  2588 slightly more general idea of ``protecting'' meta-level rule
  2589 statements.
  2590 
  2591 * Pure: Logic.(un)varify only works in a global context, which is now
  2592 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2593 Logic.legacy_(un)varify as temporary workaround.
  2594 
  2595 * Pure: structure Name provides scalable operations for generating
  2596 internal variable names, notably Name.variants etc.  This replaces
  2597 some popular functions from term.ML:
  2598 
  2599   Term.variant		->  Name.variant
  2600   Term.variantlist	->  Name.variant_list
  2601   Term.invent_names	->  Name.invent_list
  2602 
  2603 Note that low-level renaming rarely occurs in new code -- operations
  2604 from structure Variable are used instead (see below).
  2605 
  2606 * Pure: structure Variable provides fundamental operations for proper
  2607 treatment of fixed/schematic variables in a context.  For example,
  2608 Variable.import introduces fixes for schematics of given facts and
  2609 Variable.export reverses the effect (up to renaming) -- this replaces
  2610 various freeze_thaw operations.
  2611 
  2612 * Pure: structure Goal provides simple interfaces for
  2613 init/conclude/finish and tactical prove operations (replacing former
  2614 Tactic.prove).  Goal.prove is the canonical way to prove results
  2615 within a given context; Goal.prove_global is a degraded version for
  2616 theory level goals, including a global Drule.standard.  Note that
  2617 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2618 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2619 in a locale context).
  2620 
  2621 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2622 and type checking (Syntax.check_term etc.), with common combinations
  2623 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2624 which are considered legacy and await removal.
  2625 
  2626 * Pure/Syntax: generic interfaces for type unchecking
  2627 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2628 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2629 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2630 available for convenience, but refer to the very same operations using
  2631 a mere theory instead of a full context.
  2632 
  2633 * Isar: simplified treatment of user-level errors, using exception
  2634 ERROR of string uniformly.  Function error now merely raises ERROR,
  2635 without any side effect on output channels.  The Isar toplevel takes
  2636 care of proper display of ERROR exceptions.  ML code may use plain
  2637 handle/can/try; cat_error may be used to concatenate errors like this:
  2638 
  2639   ... handle ERROR msg => cat_error msg "..."
  2640 
  2641 Toplevel ML code (run directly or through the Isar toplevel) may be
  2642 embedded into the Isar toplevel with exception display/debug like
  2643 this:
  2644 
  2645   Isar.toplevel (fn () => ...)
  2646 
  2647 INCOMPATIBILITY, removed special transform_error facilities, removed
  2648 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2649 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2650 -- use plain ERROR instead.
  2651 
  2652 * Isar: theory setup now has type (theory -> theory), instead of a
  2653 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2654 
  2655 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2656 ProofContext.debug/verbose flags.
  2657 
  2658 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2659 theory before entering a proof state.  Transactions now always see a
  2660 quasi-functional intermediate checkpoint, both in interactive and
  2661 batch mode.
  2662 
  2663 * Isar: simplified interfaces for outer syntax.  Renamed
  2664 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2665 OuterSyntax.add_parsers -- this functionality is now included in
  2666 OuterSyntax.command etc.  INCOMPATIBILITY.
  2667 
  2668 * Simplifier: the simpset of a running simplification process now
  2669 contains a proof context (cf. Simplifier.the_context), which is the
  2670 very context that the initial simpset has been retrieved from (by
  2671 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2672 (solver, looper etc.) may depend on arbitrary proof data.
  2673 
  2674 * Simplifier.inherit_context inherits the proof context (plus the
  2675 local bounds) of the current simplification process; any simproc
  2676 etc. that calls the Simplifier recursively should do this!  Removed
  2677 former Simplifier.inherit_bounds, which is already included here --
  2678 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2679 specify an explicit context using Simplifier.context/theory_context.
  2680 
  2681 * Simplifier/Classical Reasoner: more abstract interfaces
  2682 change_simpset/claset for modifying the simpset/claset reference of a
  2683 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2684 INCOMPATIBILITY.
  2685 
  2686 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2687 "Trueprop" etc.
  2688 
  2689 
  2690 *** System ***
  2691 
  2692 * settings: the default heap location within ISABELLE_HOME_USER now
  2693 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2694 Isabelle installations.
  2695 
  2696 * isabelle-process: option -S (secure mode) disables some critical
  2697 operations, notably runtime compilation and evaluation of ML source
  2698 code.
  2699 
  2700 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2701 
  2702 * Support for parallel execution, using native multicore support of
  2703 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2704 independent theories, according to the given theory header
  2705 specifications. The maximum number of worker threads is specified via
  2706 usedir option -M or the "max-threads" setting in Proof General. A
  2707 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2708 to 6 on a 8-core machine.  User-code needs to observe certain
  2709 guidelines for thread-safe programming, see appendix A in the Isar
  2710 Implementation manual.
  2711 
  2712 
  2713 
  2714 New in Isabelle2005 (October 2005)
  2715 ----------------------------------
  2716 
  2717 *** General ***
  2718 
  2719 * Theory headers: the new header syntax for Isar theories is
  2720 
  2721   theory <name>
  2722   imports <theory1> ... <theoryN>
  2723   uses <file1> ... <fileM>
  2724   begin
  2725 
  2726 where the 'uses' part is optional.  The previous syntax
  2727 
  2728   theory <name> = <theory1> + ... + <theoryN>:
  2729 
  2730 will disappear in the next release.  Use isatool fixheaders to convert
  2731 existing theory files.  Note that there is no change in ancient
  2732 non-Isar theories now, but these will disappear soon.
  2733 
  2734 * Theory loader: parent theories can now also be referred to via
  2735 relative and absolute paths.
  2736 
  2737 * Command 'find_theorems' searches for a list of criteria instead of a
  2738 list of constants. Known criteria are: intro, elim, dest, name:string,
  2739 simp:term, and any term. Criteria can be preceded by '-' to select
  2740 theorems that do not match. Intro, elim, dest select theorems that
  2741 match the current goal, name:s selects theorems whose fully qualified
  2742 name contain s, and simp:term selects all simplification rules whose
  2743 lhs match term.  Any other term is interpreted as pattern and selects
  2744 all theorems matching the pattern. Available in ProofGeneral under
  2745 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2746 
  2747   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2748 
  2749 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2750 matching the current goal as introduction rule and not having "HOL."
  2751 in their name (i.e. not being defined in theory HOL).
  2752 
  2753 * Command 'thms_containing' has been discontinued in favour of
  2754 'find_theorems'; INCOMPATIBILITY.
  2755 
  2756 * Communication with Proof General is now 8bit clean, which means that
  2757 Unicode text in UTF-8 encoding may be used within theory texts (both
  2758 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2759 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2760 
  2761   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2762   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2763 
  2764 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2765 Classical Reasoner.  Typical big applications run around 2 times
  2766 faster.
  2767 
  2768 
  2769 *** Document preparation ***
  2770 
  2771 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2772 of raw sources.  Only those symbols that do not require additional
  2773 LaTeX packages (depending on comments in isabellesym.sty) are
  2774 displayed properly, everything else is left verbatim.  isatool display
  2775 and isatool print are used as front ends (these are subject to the
  2776 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2777 
  2778 * Command tags control specific markup of certain regions of text,
  2779 notably folding and hiding.  Predefined tags include "theory" (for
  2780 theory begin and end), "proof" for proof commands, and "ML" for
  2781 commands involving ML code; the additional tags "visible" and
  2782 "invisible" are unused by default.  Users may give explicit tag
  2783 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2784 interpretation of tags is determined by the LaTeX job during document
  2785 preparation: see option -V of isatool usedir, or options -n and -t of
  2786 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2787 \isadroptag.
  2788 
  2789 Several document versions may be produced at the same time via isatool
  2790 usedir (the generated index.html will link all of them).  Typical
  2791 specifications include ''-V document=theory,proof,ML'' to present
  2792 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2793 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2794 these parts without any formal replacement text.  The Isabelle site
  2795 default settings produce ''document'' and ''outline'' versions as
  2796 specified above.
  2797 
  2798 * Several new antiquotations:
  2799 
  2800   @{term_type term} prints a term with its type annotated;
  2801 
  2802   @{typeof term} prints the type of a term;
  2803 
  2804   @{const const} is the same as @{term const}, but checks that the
  2805   argument is a known logical constant;
  2806 
  2807   @{term_style style term} and @{thm_style style thm} print a term or
  2808   theorem applying a "style" to it
  2809 
  2810   @{ML text}
  2811 
  2812 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2813 definitions, equations, inequations etc., 'concl' printing only the
  2814 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2815 to print the specified premise.  TermStyle.add_style provides an ML
  2816 interface for introducing further styles.  See also the "LaTeX Sugar"
  2817 document practical applications.  The ML antiquotation prints
  2818 type-checked ML expressions verbatim.
  2819 
  2820 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2821 and 'text' support optional locale specification '(in loc)', which
  2822 specifies the default context for interpreting antiquotations.  For
  2823 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2824 
  2825 * Option 'locale=NAME' of antiquotations specifies an alternative
  2826 context interpreting the subsequent argument.  For example: @{thm
  2827 [locale=lattice] inf_assoc}.
  2828 
  2829 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2830 a proof context.
  2831 
  2832 * Proper output of antiquotations for theory commands involving a
  2833 proof context (such as 'locale' or 'theorem (in loc) ...').
  2834 
  2835 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2836 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2837 
  2838 * isatool usedir: new option -C (default true) controls whether option
  2839 -D should include a copy of the original document directory; -C false
  2840 prevents unwanted effects such as copying of administrative CVS data.
  2841 
  2842 
  2843 *** Pure ***
  2844 
  2845 * Considerably improved version of 'constdefs' command.  Now performs
  2846 automatic type-inference of declared constants; additional support for
  2847 local structure declarations (cf. locales and HOL records), see also
  2848 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2849 sequential dependencies of definitions within a single 'constdefs'
  2850 section; moreover, the declared name needs to be an identifier.  If
  2851 all fails, consider to fall back on 'consts' and 'defs' separately.
  2852 
  2853 * Improved indexed syntax and implicit structures.  First of all,
  2854 indexed syntax provides a notational device for subscripted
  2855 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2856 expressions.  Secondly, in a local context with structure
  2857 declarations, number indexes \<^sub>n or the empty index (default
  2858 number 1) refer to a certain fixed variable implicitly; option
  2859 show_structs controls printing of implicit structures.  Typical
  2860 applications of these concepts involve record types and locales.
  2861 
  2862 * New command 'no_syntax' removes grammar declarations (and
  2863 translations) resulting from the given syntax specification, which is
  2864 interpreted in the same manner as for the 'syntax' command.
  2865 
  2866 * 'Advanced' translation functions (parse_translation etc.) may depend
  2867 on the signature of the theory context being presently used for
  2868 parsing/printing, see also isar-ref manual.
  2869 
  2870 * Improved 'oracle' command provides a type-safe interface to turn an
  2871 ML expression of type theory -> T -> term into a primitive rule of
  2872 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2873 is already included here); see also FOL/ex/IffExample.thy;
  2874 INCOMPATIBILITY.
  2875 
  2876 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2877 before); "cI" is no longer bound, use "c.intro" instead.
  2878 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2879 axclasses vs. locales.
  2880 
  2881 * Improved internal renaming of symbolic identifiers -- attach primes
  2882 instead of base 26 numbers.
  2883 
  2884 * New flag show_question_marks controls printing of leading question
  2885 marks in schematic variable names.
  2886 
  2887 * In schematic variable names, *any* symbol following \<^isub> or
  2888 \<^isup> is now treated as part of the base name.  For example, the
  2889 following works without printing of awkward ".0" indexes:
  2890 
  2891   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2892     by simp
  2893 
  2894 * Inner syntax includes (*(*nested*) comments*).
  2895 
  2896 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2897 annotations as "(00...)".
  2898 
  2899 * Clear separation of logical types and nonterminals, where the latter
  2900 may only occur in 'syntax' specifications or type abbreviations.
  2901 Before that distinction was only partially implemented via type class
  2902 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2903 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2904 exotic syntax specifications may require further adaption
  2905 (e.g. Cube/Cube.thy).
  2906 
  2907 * Removed obsolete type class "logic", use the top sort {} instead.
  2908 Note that non-logical types should be declared as 'nonterminals'
  2909 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2910 specifications.
  2911 
  2912 * Attributes 'induct' and 'cases': type or set names may now be
  2913 locally fixed variables as well.
  2914 
  2915 * Simplifier: can now control the depth to which conditional rewriting
  2916 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2917 Limit.
  2918 
  2919 * Simplifier: simplification procedures may now take the current
  2920 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2921 interface), which is very useful for calling the Simplifier
  2922 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2923 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2924 low-level mk_simproc no longer applies Logic.varify internally, to
  2925 allow for use in a context of fixed variables.
  2926 
  2927 * thin_tac now works even if the assumption being deleted contains !!
  2928 or ==>.  More generally, erule now works even if the major premise of
  2929 the elimination rule contains !! or ==>.
  2930 
  2931 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2932 
  2933 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2934 from Pure, which contains all common declarations already.  Both
  2935 theories are defined via plain Isabelle/Isar .thy files.
  2936 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2937 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2938 use isatool fixcpure to adapt your theory and ML sources.
  2939 
  2940 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2941 selections of theorems in named facts via index ranges.
  2942 
  2943 * 'print_theorems': in theory mode, really print the difference
  2944 wrt. the last state (works for interactive theory development only),
  2945 in proof mode print all local facts (cf. 'print_facts');
  2946 
  2947 * 'hide': option '(open)' hides only base names.
  2948 
  2949 * More efficient treatment of intermediate checkpoints in interactive
  2950 theory development.
  2951 
  2952 * Code generator is now invoked via code_module (incremental code
  2953 generation) and code_library (modular code generation, ML structures
  2954 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2955 must be quoted when used as identifiers.
  2956 
  2957 * New 'value' command for reading, evaluating and printing terms using
  2958 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2959 quoted when used as identifier.
  2960 
  2961 
  2962 *** Locales ***
  2963 
  2964 * New commands for the interpretation of locale expressions in
  2965 theories (1), locales (2) and proof contexts (3).  These generate
  2966 proof obligations from the expression specification.  After the
  2967 obligations have been discharged, theorems of the expression are added
  2968 to the theory, target locale or proof context.  The synopsis of the
  2969 commands is a follows:
  2970 
  2971   (1) interpretation expr inst
  2972   (2) interpretation target < expr
  2973   (3) interpret expr inst
  2974 
  2975 Interpretation in theories and proof contexts require a parameter
  2976 instantiation of terms from the current context.  This is applied to
  2977 specifications and theorems of the interpreted expression.
  2978 Interpretation in locales only permits parameter renaming through the
  2979 locale expression.  Interpretation is smart in that interpretations
  2980 that are active already do not occur in proof obligations, neither are
  2981 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2982 inspect active interpretations of a particular locale.  For details,
  2983 see the Isar Reference manual.  Examples can be found in
  2984 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2985 
  2986 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2987 'interpret' instead.
  2988 
  2989 * New context element 'constrains' for adding type constraints to
  2990 parameters.
  2991 
  2992 * Context expressions: renaming of parameters with syntax
  2993 redeclaration.
  2994 
  2995 * Locale declaration: 'includes' disallowed.
  2996 
  2997 * Proper static binding of attribute syntax -- i.e. types / terms /
  2998 facts mentioned as arguments are always those of the locale definition
  2999 context, independently of the context of later invocations.  Moreover,
  3000 locale operations (renaming and type / term instantiation) are applied
  3001 to attribute arguments as expected.
  3002 
  3003 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  3004 actual attributes; rare situations may require Attrib.attribute to
  3005 embed those attributes into Attrib.src that lack concrete syntax.
  3006 Attribute implementations need to cooperate properly with the static
  3007 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  3008 Attrib.XXX_thm etc. already do the right thing without further
  3009 intervention.  Only unusual applications -- such as "where" or "of"
  3010 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  3011 on the context and the facts involved -- may have to assign parsed
  3012 values to argument tokens explicitly.
  3013 
  3014 * Changed parameter management in theorem generation for long goal
  3015 statements with 'includes'.  INCOMPATIBILITY: produces a different
  3016 theorem statement in rare situations.
  3017 
  3018 * Locale inspection command 'print_locale' omits notes elements.  Use
  3019 'print_locale!' to have them included in the output.
  3020 
  3021 
  3022 *** Provers ***
  3023 
  3024 * Provers/hypsubst.ML: improved version of the subst method, for
  3025 single-step rewriting: it now works in bound variable contexts. New is
  3026 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  3027 rewrite a different subterm than the original subst method, which is
  3028 still available as 'simplesubst'.
  3029 
  3030 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  3031 and quasi orders.
  3032 
  3033 * Provers/trancl.ML: new transitivity reasoner for transitive and
  3034 reflexive-transitive closure of relations.
  3035 
  3036 * Provers/blast.ML: new reference depth_limit to make blast's depth
  3037 limit (previously hard-coded with a value of 20) user-definable.
  3038 
  3039 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  3040 is peformed already.  Object-logics merely need to finish their
  3041 initial simpset configuration as before.  INCOMPATIBILITY.
  3042 
  3043 
  3044 *** HOL ***
  3045 
  3046 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3047 
  3048   syntax (epsilon)
  3049     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3050 
  3051 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3052 and x-symbol; use option '-m epsilon' to get it actually printed.
  3053 Moreover, the mathematically important symbolic identifier \<epsilon>
  3054 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3055 
  3056 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3057 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3058 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3059 support corresponding Isar calculations.
  3060 
  3061 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3062 instead of ":".
  3063 
  3064 * theory SetInterval: changed the syntax for open intervals:
  3065 
  3066   Old       New
  3067   {..n(}    {..<n}
  3068   {)n..}    {n<..}
  3069   {m..n(}   {m..<n}
  3070   {)m..n}   {m<..n}
  3071   {)m..n(}  {m<..<n}
  3072 
  3073 The old syntax is still supported but will disappear in the next
  3074 release.  For conversion use the following Emacs search and replace
  3075 patterns (these are not perfect but work quite well):
  3076 
  3077   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3078   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3079 
  3080 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3081 equalities in commutative rings; method 'algebra' provides a generic
  3082 interface.
  3083 
  3084 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3085 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3086 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3087 be a tuple pattern.
  3088 
  3089 Some new syntax forms are available:
  3090 
  3091   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3092   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3093   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3094   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3095 
  3096 The latter form "\<Sum>x < k. e" used to be based on a separate
  3097 function "Summation", which has been discontinued.
  3098 
  3099 * theory Finite_Set: in structured induction proofs, the insert case
  3100 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3101 (insert F x)'.
  3102 
  3103 * The 'refute' command has been extended to support a much larger
  3104 fragment of HOL, including axiomatic type classes, constdefs and
  3105 typedefs, inductive datatypes and recursion.
  3106 
  3107 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3108 Requires zChaff with proof generation to be installed.  See
  3109 HOL/ex/SAT_Examples.thy for examples.
  3110 
  3111 * Datatype induction via method 'induct' now preserves the name of the
  3112 induction variable. For example, when proving P(xs::'a list) by
  3113 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3114 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3115 in unstructured proof scripts.
  3116 
  3117 * Reworked implementation of records.  Improved scalability for
  3118 records with many fields, avoiding performance problems for type
  3119 inference. Records are no longer composed of nested field types, but
  3120 of nested extension types. Therefore the record type only grows linear
  3121 in the number of extensions and not in the number of fields.  The
  3122 top-level (users) view on records is preserved.  Potential
  3123 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3124 old record representation. The type generated for a record is called
  3125 <record_name>_ext_type.
  3126 
  3127 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3128 proofs triggered by a record definition or a simproc (if
  3129 quick_and_dirty is enabled).  Definitions of large records can take
  3130 quite long.
  3131 
  3132 New simproc record_upd_simproc for simplification of multiple record
  3133 updates enabled by default.  Moreover, trivial updates are also
  3134 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3135 occasionally, since simplification is more powerful by default.
  3136 
  3137 * typedef: proper support for polymorphic sets, which contain extra
  3138 type-variables in the term.
  3139 
  3140 * Simplifier: automatically reasons about transitivity chains
  3141 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3142 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3143 old proofs break occasionally as simplification may now solve more
  3144 goals than previously.
  3145 
  3146 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3147 present.  Works for all partial orders (class "order"), in particular
  3148 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3149 just like y <= x.
  3150 
  3151 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3152 bound variable or a constant then the let is unfolded.  Otherwise
  3153 first a is simplified to b, and then f b is simplified to g. If
  3154 possible we abstract b from g arriving at "let x = b in h x",
  3155 otherwise we unfold the let and arrive at g.  The simproc can be
  3156 enabled/disabled by the reference use_let_simproc.  Potential
  3157 INCOMPATIBILITY since simplification is more powerful by default.
  3158 
  3159 * Classical reasoning: the meson method now accepts theorems as arguments.
  3160 
  3161 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3162 jobs to provide advice on the provability of subgoals.
  3163 
  3164 * Theory OrderedGroup and Ring_and_Field: various additions and
  3165 improvements to faciliate calculations involving equalities and
  3166 inequalities.
  3167 
  3168 The following theorems have been eliminated or modified
  3169 (INCOMPATIBILITY):
  3170 
  3171   abs_eq             now named abs_of_nonneg
  3172   abs_of_ge_0        now named abs_of_nonneg
  3173   abs_minus_eq       now named abs_of_nonpos
  3174   imp_abs_id         now named abs_of_nonneg
  3175   imp_abs_neg_id     now named abs_of_nonpos
  3176   mult_pos           now named mult_pos_pos
  3177   mult_pos_le        now named mult_nonneg_nonneg
  3178   mult_pos_neg_le    now named mult_nonneg_nonpos
  3179   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3180   mult_neg           now named mult_neg_neg
  3181   mult_neg_le        now named mult_nonpos_nonpos
  3182 
  3183 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3184      
  3185      zero_le_square
  3186      not_square_less_zero 
  3187 
  3188   The following lemmas have been deleted from Real/RealPow:
  3189   
  3190      realpow_zero_zero
  3191      realpow_two
  3192      realpow_less
  3193      zero_le_power
  3194      realpow_two_le
  3195      abs_realpow_two
  3196      realpow_two_abs     
  3197 
  3198 * Theory Parity: added rules for simplifying exponents.
  3199 
  3200 * Theory List:
  3201 
  3202 The following theorems have been eliminated or modified
  3203 (INCOMPATIBILITY):
  3204 
  3205   list_all_Nil       now named list_all.simps(1)
  3206   list_all_Cons      now named list_all.simps(2)
  3207   list_all_conv      now named list_all_iff
  3208   set_mem_eq         now named mem_iff
  3209 
  3210 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3211 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3212 
  3213 
  3214 *** HOL-Complex ***
  3215 
  3216 * Theory RealDef: better support for embedding natural numbers and
  3217 integers in the reals.
  3218 
  3219 The following theorems have been eliminated or modified
  3220 (INCOMPATIBILITY):
  3221 
  3222   exp_ge_add_one_self  now requires no hypotheses
  3223   real_of_int_add      reversed direction of equality (use [symmetric])
  3224   real_of_int_minus    reversed direction of equality (use [symmetric])
  3225   real_of_int_diff     reversed direction of equality (use [symmetric])
  3226   real_of_int_mult     reversed direction of equality (use [symmetric])
  3227 
  3228 * Theory RComplete: expanded support for floor and ceiling functions.
  3229 
  3230 * Theory Ln is new, with properties of the natural logarithm
  3231 
  3232 * Hyperreal: There is a new type constructor "star" for making
  3233 nonstandard types.  The old type names are now type synonyms:
  3234 
  3235   hypreal = real star
  3236   hypnat = nat star
  3237   hcomplex = complex star
  3238 
  3239 * Hyperreal: Many groups of similarly-defined constants have been
  3240 replaced by polymorphic versions (INCOMPATIBILITY):
  3241 
  3242   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3243 
  3244   starset      <-- starsetNat, starsetC
  3245   *s*          <-- *sNat*, *sc*
  3246   starset_n    <-- starsetNat_n, starsetC_n
  3247   *sn*         <-- *sNatn*, *scn*
  3248   InternalSets <-- InternalNatSets, InternalCSets
  3249 
  3250   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3251   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3252   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3253   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3254   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3255 
  3256 * Hyperreal: Many type-specific theorems have been removed in favor of
  3257 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3258 
  3259   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3260   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3261   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3262   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3263   right_minus <-- hypreal_add_minus
  3264   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3265   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3266   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3267   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3268   mult_1_right <-- hcomplex_mult_one_right
  3269   mult_zero_left <-- hcomplex_mult_zero_left
  3270   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3271   right_distrib <-- hypnat_add_mult_distrib2
  3272   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3273   right_inverse <-- hypreal_mult_inverse
  3274   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3275   order_refl <-- {hypreal,hypnat}_le_refl
  3276   order_trans <-- {hypreal,hypnat}_le_trans
  3277   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3278   order_less_le <-- {hypreal,hypnat}_less_le
  3279   linorder_linear <-- {hypreal,hypnat}_le_linear
  3280   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3281   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3282   add_nonneg_nonneg <-- hypreal_le_add_order
  3283 
  3284 * Hyperreal: Separate theorems having to do with type-specific
  3285 versions of constants have been merged into theorems that apply to the
  3286 new polymorphic constants (INCOMPATIBILITY):
  3287 
  3288   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3289   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3290   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3291   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3292   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3293   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3294   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3295   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3296   STAR_diff <-- {STAR,STARC}_diff
  3297   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3298     STARC_hcomplex_of_complex}_image_subset
  3299   starset_n_Un <-- starset{Nat,C}_n_Un
  3300   starset_n_Int <-- starset{Nat,C}_n_Int
  3301   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3302   starset_n_diff <-- starset{Nat,C}_n_diff
  3303   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3304   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3305   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3306   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3307   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3308   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3309   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3310   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3311   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3312   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3313   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3314   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3315   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3316   starfun_diff <-- starfun{C,RC,CR}_diff
  3317   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3318   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3319   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3320   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3321   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3322   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3323   starfun_Id <-- starfunC_Id
  3324   starfun_approx <-- starfun{Nat,CR}_approx
  3325   starfun_capprox <-- starfun{C,RC}_capprox
  3326   starfun_abs <-- starfunNat_rabs
  3327   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3328   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3329   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3330   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3331   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3332   starfun_add_approx <-- starfunCR_add_approx
  3333   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3334   starfun_divide <-- starfun{C,CR,RC}_divide
  3335   starfun_n <-- starfun{Nat,C}_n
  3336   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3337   starfun_n_add <-- starfun{Nat,C}_n_add
  3338   starfun_n_add_minus <-- starfunNat_n_add_minus
  3339   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3340   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3341   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3342 
  3343   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3344   star_n_minus <-- {hypreal,hcomplex}_minus
  3345   star_n_diff <-- {hypreal,hcomplex}_diff
  3346   star_n_mult <-- {hypreal,hcomplex}_mult
  3347   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3348   star_n_le <-- {hypreal,hypnat}_le
  3349   star_n_less <-- {hypreal,hypnat}_less
  3350   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3351   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3352   star_n_abs <-- hypreal_hrabs
  3353   star_n_divide <-- hcomplex_divide
  3354 
  3355   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3356   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3357   star_of_diff <-- hypreal_of_real_diff
  3358   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3359   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3360   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3361   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3362   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3363   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3364   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3365   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3366   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3367   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3368   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3369   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3370   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3371   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3372   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3373   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3374   star_of_power <-- hypreal_of_real_power
  3375   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3376 
  3377 * Hyperreal: new method "transfer" that implements the transfer
  3378 principle of nonstandard analysis. With a subgoal that mentions
  3379 nonstandard types like "'a star", the command "apply transfer"
  3380 replaces it with an equivalent one that mentions only standard types.
  3381 To be successful, all free variables must have standard types; non-
  3382 standard variables must have explicit universal quantifiers.
  3383 
  3384 * Hyperreal: A theory of Taylor series.
  3385 
  3386 
  3387 *** HOLCF ***
  3388 
  3389 * Discontinued special version of 'constdefs' (which used to support
  3390 continuous functions) in favor of the general Pure one with full
  3391 type-inference.
  3392 
  3393 * New simplification procedure for solving continuity conditions; it
  3394 is much faster on terms with many nested lambda abstractions (cubic
  3395 instead of exponential time).
  3396 
  3397 * New syntax for domain package: selector names are now optional.
  3398 Parentheses should be omitted unless argument is lazy, for example:
  3399 
  3400   domain 'a stream = cons "'a" (lazy "'a stream")
  3401 
  3402 * New command 'fixrec' for defining recursive functions with pattern
  3403 matching; defining multiple functions with mutual recursion is also
  3404 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3405 sinr, or any data constructor defined by the domain package. The given
  3406 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3407 syntax and examples.
  3408 
  3409 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3410 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3411 but the proof obligation additionally includes an admissibility
  3412 requirement. The packages generate instances of class cpo or pcpo,
  3413 with continuity and strictness theorems for Rep and Abs.
  3414 
  3415 * HOLCF: Many theorems have been renamed according to a more standard naming
  3416 scheme (INCOMPATIBILITY):
  3417 
  3418   foo_inject:  "foo$x = foo$y ==> x = y"
  3419   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3420   foo_less:    "(foo$x << foo$y) = (x << y)"
  3421   foo_strict:  "foo$UU = UU"
  3422   foo_defined: "... ==> foo$x ~= UU"
  3423   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3424 
  3425 
  3426 *** ZF ***
  3427 
  3428 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3429 including the First Isomorphism Theorem (on quotienting by the kernel
  3430 of a homomorphism).
  3431 
  3432 * ZF/Simplifier: install second copy of type solver that actually
  3433 makes use of TC rules declared to Isar proof contexts (or locales);
  3434 the old version is still required for ML proof scripts.
  3435 
  3436 
  3437 *** Cube ***
  3438 
  3439 * Converted to Isar theory format; use locales instead of axiomatic
  3440 theories.
  3441 
  3442 
  3443 *** ML ***
  3444 
  3445 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3446 for ||>, ||>>, |>>,
  3447 
  3448 * Pure/library.ML no longer defines its own option datatype, but uses
  3449 that of the SML basis, which has constructors NONE and SOME instead of
  3450 None and Some, as well as exception Option.Option instead of OPTION.
  3451 The functions the, if_none, is_some, is_none have been adapted
  3452 accordingly, while Option.map replaces apsome.
  3453 
  3454 * Pure/library.ML: the exception LIST has been given up in favour of
  3455 the standard exceptions Empty and Subscript, as well as
  3456 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3457 superceded by the standard hd and tl functions etc.
  3458 
  3459 A number of basic list functions are no longer exported to the ML
  3460 toplevel, as they are variants of predefined functions.  The following
  3461 suggests how one can translate existing code:
  3462 
  3463     rev_append xs ys = List.revAppend (xs, ys)
  3464     nth_elem (i, xs) = List.nth (xs, i)
  3465     last_elem xs = List.last xs
  3466     flat xss = List.concat xss
  3467     seq fs = List.app fs
  3468     partition P xs = List.partition P xs
  3469     mapfilter f xs = List.mapPartial f xs
  3470 
  3471 * Pure/library.ML: several combinators for linear functional
  3472 transformations, notably reverse application and composition:
  3473 
  3474   x |> f                f #> g
  3475   (x, y) |-> f          f #-> g
  3476 
  3477 * Pure/library.ML: introduced/changed precedence of infix operators:
  3478 
  3479   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3480   infix 2 ?;
  3481   infix 3 o oo ooo oooo;
  3482   infix 4 ~~ upto downto;
  3483 
  3484 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3485 infix operators.
  3486 
  3487 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3488 fold_map support linear functional transformations and nesting.  For
  3489 example:
  3490 
  3491   fold f [x1, ..., xN] y =
  3492     y |> f x1 |> ... |> f xN
  3493 
  3494   (fold o fold) f [xs1, ..., xsN] y =
  3495     y |> fold f xs1 |> ... |> fold f xsN
  3496 
  3497   fold f [x1, ..., xN] =
  3498     f x1 #> ... #> f xN
  3499 
  3500   (fold o fold) f [xs1, ..., xsN] =
  3501     fold f xs1 #> ... #> fold f xsN
  3502 
  3503 * Pure/library.ML: the following selectors on type 'a option are
  3504 available:
  3505 
  3506   the:               'a option -> 'a  (*partial*)
  3507   these:             'a option -> 'a  where 'a = 'b list
  3508   the_default: 'a -> 'a option -> 'a
  3509   the_list:          'a option -> 'a list
  3510 
  3511 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3512 basic operations for association lists, following natural argument
  3513 order; moreover the explicit equality predicate passed here avoids
  3514 potentially expensive polymorphic runtime equality checks.
  3515 The old functions may be expressed as follows:
  3516 
  3517   assoc = uncurry (AList.lookup (op =))
  3518   assocs = these oo AList.lookup (op =)
  3519   overwrite = uncurry (AList.update (op =)) o swap
  3520 
  3521 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3522 
  3523   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3524   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3525 
  3526 replacing make_keylist and keyfilter (occassionally used)
  3527 Naive rewrites:
  3528 
  3529   make_keylist = AList.make
  3530   keyfilter = AList.find (op =)
  3531 
  3532 * eq_fst and eq_snd now take explicit equality parameter, thus
  3533   avoiding eqtypes. Naive rewrites:
  3534 
  3535     eq_fst = eq_fst (op =)
  3536     eq_snd = eq_snd (op =)
  3537 
  3538 * Removed deprecated apl and apr (rarely used).
  3539   Naive rewrites:
  3540 
  3541     apl (n, op) =>>= curry op n
  3542     apr (op, m) =>>= fn n => op (n, m)
  3543 
  3544 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3545 provides a reasonably efficient light-weight implementation of sets as
  3546 lists.
  3547 
  3548 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3549 few new operations; existing lookup and update are now curried to
  3550 follow natural argument order (for use with fold etc.);
  3551 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3552 
  3553 * Pure/General: output via the Isabelle channels of
  3554 writeln/warning/error etc. is now passed through Output.output, with a
  3555 hook for arbitrary transformations depending on the print_mode
  3556 (cf. Output.add_mode -- the first active mode that provides a output
  3557 function wins).  Already formatted output may be embedded into further
  3558 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3559 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3560 accommodate easy composition of diagnostic messages etc.  Programmers
  3561 rarely need to care about Output.output or Output.raw at all, with
  3562 some notable exceptions: Output.output is required when bypassing the
  3563 standard channels (writeln etc.), or in token translations to produce
  3564 properly formatted results; Output.raw is required when capturing
  3565 already output material that will eventually be presented to the user
  3566 a second time.  For the default print mode, both Output.output and
  3567 Output.raw have no effect.
  3568 
  3569 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3570 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3571 cumulative results are displayed at the end of a batch session.
  3572 
  3573 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3574 replaced by File.platform_path and File.shell_path (with appropriate
  3575 hooks).  This provides a clean interface for unusual systems where the
  3576 internal and external process view of file names are different.
  3577 
  3578 * Pure: more efficient orders for basic syntactic entities: added
  3579 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3580 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3581 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3582 orders now -- potential INCOMPATIBILITY for code that depends on a
  3583 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3584 Library.sort_strings on result).
  3585 
  3586 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3587 fold_types traverse types/terms from left to right, observing natural
  3588 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3589 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3590 
  3591 * Pure: name spaces have been refined, with significant changes of the
  3592 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3593 to extern(_table).  The plain name entry path is superceded by a
  3594 general 'naming' context, which also includes the 'policy' to produce
  3595 a fully qualified name and external accesses of a fully qualified
  3596 name; NameSpace.extend is superceded by context dependent
  3597 Sign.declare_name.  Several theory and proof context operations modify
  3598 the naming context.  Especially note Theory.restore_naming and
  3599 ProofContext.restore_naming to get back to a sane state; note that
  3600 Theory.add_path is no longer sufficient to recover from
  3601 Theory.absolute_path in particular.
  3602 
  3603 * Pure: new flags short_names (default false) and unique_names
  3604 (default true) for controlling output of qualified names.  If
  3605 short_names is set, names are printed unqualified.  If unique_names is
  3606 reset, the name prefix is reduced to the minimum required to achieve
  3607 the original result when interning again, even if there is an overlap
  3608 with earlier declarations.
  3609 
  3610 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3611 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3612 (useful for printing error messages).  INCOMPATIBILITY.
  3613 
  3614 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3615 Theory.theory are now identified, referring to the universal
  3616 Context.theory (see Pure/context.ML).  Actual signature and theory
  3617 content is managed as theory data.  The old code and interfaces were
  3618 spread over many files and structures; the new arrangement introduces
  3619 considerable INCOMPATIBILITY to gain more clarity:
  3620 
  3621   Context -- theory management operations (name, identity, inclusion,
  3622     parents, ancestors, merge, etc.), plus generic theory data;
  3623 
  3624   Sign -- logical signature and syntax operations (declaring consts,
  3625     types, etc.), plus certify/read for common entities;
  3626 
  3627   Theory -- logical theory operations (stating axioms, definitions,
  3628     oracles), plus a copy of logical signature operations (consts,
  3629     types, etc.); also a few basic management operations (Theory.copy,
  3630     Theory.merge, etc.)
  3631 
  3632 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3633 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3634 for convenience -- they merely return the theory.
  3635 
  3636 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3637 
  3638 * Pure: the Isar proof context type is already defined early in Pure
  3639 as Context.proof (note that ProofContext.context and Proof.context are
  3640 aliases, where the latter is the preferred name).  This enables other
  3641 Isabelle components to refer to that type even before Isar is present.
  3642 
  3643 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3644 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3645 any of these kinds.  For example, Sign.intern typeK is now
  3646 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3647 Theory.hide_types.  Also note that former
  3648 Theory.hide_classes/types/consts are now
  3649 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3650 internalize their arguments!  INCOMPATIBILITY.
  3651 
  3652 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3653 datatype thmref (with constructors Name and NameSelection) instead of
  3654 plain string -- INCOMPATIBILITY;
  3655 
  3656 * Pure: cases produced by proof methods specify options, where NONE
  3657 means to remove case bindings -- INCOMPATIBILITY in
  3658 (RAW_)METHOD_CASES.
  3659 
  3660 * Pure: the following operations retrieve axioms or theorems from a
  3661 theory node or theory hierarchy, respectively:
  3662 
  3663   Theory.axioms_of: theory -> (string * term) list
  3664   Theory.all_axioms_of: theory -> (string * term) list
  3665   PureThy.thms_of: theory -> (string * thm) list
  3666   PureThy.all_thms_of: theory -> (string * thm) list
  3667 
  3668 * Pure: print_tac now outputs the goal through the trace channel.
  3669 
  3670 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3671 Reference Toplevel.debug (default false) controls detailed printing
  3672 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3673 controls execution profiling -- set to 1 for time and 2 for space
  3674 (both increase the runtime).
  3675 
  3676 * Isar session: The initial use of ROOT.ML is now always timed,
  3677 i.e. the log will show the actual process times, in contrast to the
  3678 elapsed wall-clock time that the outer shell wrapper produces.
  3679 
  3680 * Simplifier: improved handling of bound variables (nameless
  3681 representation, avoid allocating new strings).  Simprocs that invoke
  3682 the Simplifier recursively should use Simplifier.inherit_bounds to
  3683 avoid local name clashes.  Failure to do so produces warnings
  3684 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3685 for further details.
  3686 
  3687 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3688 bindings for all theorems stored within a given theory; this may help
  3689 in porting non-Isar theories to Isar ones, while keeping ML proof
  3690 scripts for the time being.
  3691 
  3692 * ML operator HTML.with_charset specifies the charset begin used for
  3693 generated HTML files.  For example:
  3694 
  3695   HTML.with_charset "utf-8" use_thy "Hebrew";
  3696   HTML.with_charset "utf-8" use_thy "Chinese";
  3697 
  3698 
  3699 *** System ***
  3700 
  3701 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3702 isabelle, isatool etc.).
  3703 
  3704 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3705 isatool doc, isatool mkdir, display_drafts etc.).
  3706 
  3707 * isatool usedir: option -f allows specification of the ML file to be
  3708 used by Isabelle; default is ROOT.ML.
  3709 
  3710 * New isatool version outputs the version identifier of the Isabelle
  3711 distribution being used.
  3712 
  3713 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3714 (containing Boolean satisfiability problems) into Isabelle/HOL
  3715 theories.
  3716 
  3717 
  3718 
  3719 New in Isabelle2004 (April 2004)
  3720 --------------------------------
  3721 
  3722 *** General ***
  3723 
  3724 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3725   Replaces linorder.ML.
  3726 
  3727 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3728   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3729   (\<a>...\<z>), are now considered normal letters, and can therefore
  3730   be used anywhere where an ASCII letter (a...zA...Z) has until
  3731   now. COMPATIBILITY: This obviously changes the parsing of some
  3732   terms, especially where a symbol has been used as a binder, say
  3733   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3734   as an identifier.  Fix it by inserting a space around former
  3735   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3736   existing theory and ML files.
  3737 
  3738 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3739 
  3740 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3741   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3742   a normal (but invisible) letter. For multiple letter subscripts repeat
  3743   \<^isub> like this: x\<^isub>1\<^isub>2.
  3744 
  3745 * Pure: There are now sub-/superscripts that can span more than one
  3746   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3747   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3748   superscript. The new control characters are not identifier parts.
  3749 
  3750 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3751   content of "..." to the latex file instead of \isacntrl... . The "..."
  3752   may consist of any printable characters excluding the end bracket >.
  3753 
  3754 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3755   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3756   declare constants "final", which prevents their being given a definition
  3757   later.  It is useful for constants whose behaviour is fixed axiomatically
  3758   rather than definitionally, such as the meta-logic connectives.
  3759 
  3760 * Pure: 'instance' now handles general arities with general sorts
  3761   (i.e. intersections of classes),
  3762 
  3763 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3764   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3765   It can be changed to alter the colors/layout of generated pages.
  3766 
  3767 
  3768 *** Isar ***
  3769 
  3770 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3771   cut_tac, subgoal_tac and thin_tac:
  3772   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3773     locales are no longer forced to write Isar proof scripts.
  3774     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3775     emulations.
  3776   - INCOMPATIBILITY: names of variables to be instantiated may no
  3777     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3778     This is consistent with the instantiation attribute "where".
  3779 
  3780 * Attributes "where" and "of":
  3781   - Now take type variables of instantiated theorem into account when reading
  3782     the instantiation string.  This fixes a bug that caused instantiated
  3783     theorems to have too special types in some circumstances.
  3784   - "where" permits explicit instantiations of type variables.
  3785 
  3786 * Calculation commands "moreover" and "also" no longer interfere with
  3787   current facts ("this"), admitting arbitrary combinations with "then"
  3788   and derived forms.
  3789 
  3790 * Locales:
  3791   - Goal statements involving the context element "includes" no longer
  3792     generate theorems with internal delta predicates (those ending on
  3793     "_axioms") in the premise.
  3794     Resolve particular premise with <locale>.intro to obtain old form.
  3795   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3796     specification and "includes" elements in goal statement.
  3797   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3798     [intro?] and [elim?] (respectively) by default.
  3799   - Experimental command for instantiation of locales in proof contexts:
  3800         instantiate <label>[<attrs>]: <loc>
  3801     Instantiates locale <loc> and adds all its theorems to the current context
  3802     taking into account their attributes.  Label and attrs are optional
  3803     modifiers, like in theorem declarations.  If present, names of
  3804     instantiated theorems are qualified with <label>, and the attributes
  3805     <attrs> are applied after any attributes these theorems might have already.
  3806       If the locale has assumptions, a chained fact of the form
  3807     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3808     are derived.  The command does not support old-style locales declared
  3809     with "locale (open)".
  3810       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3811 
  3812 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3813   (Isar) contexts.
  3814 
  3815 
  3816 *** HOL ***
  3817 
  3818 * Proof import: new image HOL4 contains the imported library from
  3819   the HOL4 system with about 2500 theorems. It is imported by
  3820   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3821   can be used like any other Isabelle image.  See
  3822   HOL/Import/HOL/README for more information.
  3823 
  3824 * Simplifier:
  3825   - Much improved handling of linear and partial orders.
  3826     Reasoners for linear and partial orders are set up for type classes
  3827     "linorder" and "order" respectively, and are added to the default simpset
  3828     as solvers.  This means that the simplifier can build transitivity chains
  3829     to solve goals from the assumptions.
  3830   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3831     of blast or auto after simplification become unnecessary because the goal
  3832     is solved by simplification already.
  3833 
  3834 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3835     all proved in axiomatic type classes for semirings, rings and fields.
  3836 
  3837 * Numerics:
  3838   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3839     now formalized using the Ring_and_Field theory mentioned above.
  3840   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3841     than before, because now they are set up once in a generic manner.
  3842   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3843     Look for the general versions in Ring_and_Field (and Power if they concern
  3844     exponentiation).
  3845 
  3846 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3847 
  3848 * Records:
  3849   - Record types are now by default printed with their type abbreviation
  3850     instead of the list of all field types. This can be configured via
  3851     the reference "print_record_type_abbr".
  3852   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3853     (not enabled by default).
  3854   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3855     EX x. x = sel r to True (not enabled by default).
  3856   - Tactic "record_split_simp_tac" to split and simplify records added.
  3857 
  3858 * 'specification' command added, allowing for definition by
  3859   specification.  There is also an 'ax_specification' command that
  3860   introduces the new constants axiomatically.
  3861 
  3862 * arith(_tac) is now able to generate counterexamples for reals as well.
  3863 
  3864 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3865 
  3866 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3867   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3868 
  3869 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3870   matrix theory to linear programming.
  3871 
  3872 * Unions and Intersections:
  3873   The latex output syntax of UN and INT has been changed
  3874   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3875   i.e. the index formulae has become a subscript.
  3876   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3877 
  3878 * Unions and Intersections over Intervals:
  3879   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3880   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3881   like in normal math, and corresponding versions for < and for intersection.
  3882 
  3883 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3884   lexicographic dictonary ordering has been added as "lexord".
  3885 
  3886 * ML: the legacy theory structures Int and List have been removed. They had
  3887   conflicted with ML Basis Library structures having the same names.
  3888 
  3889 * 'refute' command added to search for (finite) countermodels.  Only works
  3890   for a fragment of HOL.  The installation of an external SAT solver is
  3891   highly recommended.  See "HOL/Refute.thy" for details.
  3892 
  3893 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3894   formulae under an assignment of free variables to random values.
  3895   In contrast to 'refute', it can deal with inductive datatypes,
  3896   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3897   for examples.
  3898 
  3899 
  3900 *** HOLCF ***
  3901 
  3902 * Streams now come with concatenation and are part of the HOLCF image
  3903 
  3904 
  3905 
  3906 New in Isabelle2003 (May 2003)
  3907 ------------------------------
  3908 
  3909 *** General ***
  3910 
  3911 * Provers/simplifier:
  3912 
  3913   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3914     Assumptions are now subject to complete mutual simplification,
  3915     not just from left to right. The simplifier now preserves
  3916     the order of assumptions.
  3917 
  3918     Potential INCOMPATIBILITY:
  3919 
  3920     -- simp sometimes diverges where the old version did
  3921        not, e.g. invoking simp on the goal
  3922 
  3923         [| P (f x); y = x; f x = f y |] ==> Q
  3924 
  3925        now gives rise to the infinite reduction sequence
  3926 
  3927         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3928 
  3929        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3930        kind of problem.
  3931 
  3932     -- Tactics combining classical reasoner and simplification (such as auto)
  3933        are also affected by this change, because many of them rely on
  3934        simp. They may sometimes diverge as well or yield a different numbers
  3935        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3936        in case of problems. Sometimes subsequent calls to the classical
  3937        reasoner will fail because a preceeding call to the simplifier too
  3938        eagerly simplified the goal, e.g. deleted redundant premises.
  3939 
  3940   - The simplifier trace now shows the names of the applied rewrite rules
  3941 
  3942   - You can limit the number of recursive invocations of the simplifier
  3943     during conditional rewriting (where the simplifie tries to solve the
  3944     conditions before applying the rewrite rule):
  3945     ML "simp_depth_limit := n"
  3946     where n is an integer. Thus you can force termination where previously
  3947     the simplifier would diverge.
  3948 
  3949   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3950 
  3951   - No longer aborts on failed congruence proof.  Instead, the
  3952     congruence is ignored.
  3953 
  3954 * Pure: New generic framework for extracting programs from constructive
  3955   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3956   as HOL/Extraction for some case studies.
  3957 
  3958 * Pure: The main goal of the proof state is no longer shown by default, only
  3959 the subgoals. This behaviour is controlled by a new flag.
  3960    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3961 (ML: Proof.show_main_goal).
  3962 
  3963 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3964 rules whose conclusion matches subgoal 1:
  3965       PG menu: Isabelle/Isar -> Show me -> matching rules
  3966 The rules are ordered by how closely they match the subgoal.
  3967 In particular, rules that solve a subgoal outright are displayed first
  3968 (or rather last, the way they are printed).
  3969 (ML: ProofGeneral.print_intros())
  3970 
  3971 * Pure: New flag trace_unify_fail causes unification to print
  3972 diagnostic information (PG: in trace buffer) when it fails. This is
  3973 useful for figuring out why single step proofs like rule, erule or
  3974 assumption failed.
  3975 
  3976 * Pure: Locale specifications now produce predicate definitions
  3977 according to the body of text (covering assumptions modulo local
  3978 definitions); predicate "loc_axioms" covers newly introduced text,
  3979 while "loc" is cumulative wrt. all included locale expressions; the
  3980 latter view is presented only on export into the global theory
  3981 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3982 on the old view without predicates;
  3983 
  3984 * Pure: predefined locales "var" and "struct" are useful for sharing
  3985 parameters (as in CASL, for example); just specify something like
  3986 ``var x + var y + struct M'' as import;
  3987 
  3988 * Pure: improved thms_containing: proper indexing of facts instead of
  3989 raw theorems; check validity of results wrt. current name space;
  3990 include local facts of proof configuration (also covers active
  3991 locales), cover fixed variables in index; may use "_" in term
  3992 specification; an optional limit for the number of printed facts may
  3993 be given (the default is 40);
  3994 
  3995 * Pure: disallow duplicate fact bindings within new-style theory files
  3996 (batch-mode only);
  3997 
  3998 * Provers: improved induct method: assumptions introduced by case
  3999 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  4000 the goal statement); "foo" still refers to all facts collectively;
  4001 
  4002 * Provers: the function blast.overloaded has been removed: all constants
  4003 are regarded as potentially overloaded, which improves robustness in exchange
  4004 for slight decrease in efficiency;
  4005 
  4006 * Provers/linorder: New generic prover for transitivity reasoning over
  4007 linear orders.  Note: this prover is not efficient!
  4008 
  4009 * Isar: preview of problems to finish 'show' now produce an error
  4010 rather than just a warning (in interactive mode);
  4011 
  4012 
  4013 *** HOL ***
  4014 
  4015 * arith(_tac)
  4016 
  4017  - Produces a counter example if it cannot prove a goal.
  4018    Note that the counter example may be spurious if the goal is not a formula
  4019    of quantifier-free linear arithmetic.
  4020    In ProofGeneral the counter example appears in the trace buffer.
  4021 
  4022  - Knows about div k and mod k where k is a numeral of type nat or int.
  4023 
  4024  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  4025    linear arithmetic fails. This takes account of quantifiers and divisibility.
  4026    Presburger arithmetic can also be called explicitly via presburger(_tac).
  4027 
  4028 * simp's arithmetic capabilities have been enhanced a bit: it now
  4029 takes ~= in premises into account (by performing a case split);
  4030 
  4031 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  4032 are distributed over a sum of terms;
  4033 
  4034 * New tactic "trans_tac" and method "trans" instantiate
  4035 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  4036 "<=", "<" and "=").
  4037 
  4038 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  4039 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  4040 
  4041 * 'typedef' command has new option "open" to suppress the set
  4042 definition;
  4043 
  4044 * functions Min and Max on finite sets have been introduced (theory
  4045 Finite_Set);
  4046 
  4047 * attribute [symmetric] now works for relations as well; it turns
  4048 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4049 
  4050 * induct over a !!-quantified statement (say !!x1..xn):
  4051   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4052 
  4053 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4054 %x. None. Warning: empty_def now refers to the previously hidden definition
  4055 of the empty set.
  4056 
  4057 * Algebra: formalization of classical algebra.  Intended as base for
  4058 any algebraic development in Isabelle.  Currently covers group theory
  4059 (up to Sylow's theorem) and ring theory (Universal Property of
  4060 Univariate Polynomials).  Contributions welcome;
  4061 
  4062 * GroupTheory: deleted, since its material has been moved to Algebra;
  4063 
  4064 * Complex: new directory of the complex numbers with numeric constants,
  4065 nonstandard complex numbers, and some complex analysis, standard and
  4066 nonstandard (Jacques Fleuriot);
  4067 
  4068 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4069 
  4070 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4071 Fleuriot);
  4072 
  4073 * Real/HahnBanach: updated and adapted to locales;
  4074 
  4075 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4076 Gray and Kramer);
  4077 
  4078 * UNITY: added the Meier-Sanders theory of progress sets;
  4079 
  4080 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4081 as abstract algorithms, instantiated to the JVM;
  4082 
  4083 * Bali: Java source language formalization. Type system, operational
  4084 semantics, axiomatic semantics. Supported language features:
  4085 classes, interfaces, objects,virtual methods, static methods,
  4086 static/instance fields, arrays, access modifiers, definite
  4087 assignment, exceptions.
  4088 
  4089 
  4090 *** ZF ***
  4091 
  4092 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4093 universe, etc.);
  4094 
  4095 * Main ZF: virtually all theories converted to new-style format;
  4096 
  4097 
  4098 *** ML ***
  4099 
  4100 * Pure: Tactic.prove provides sane interface for internal proofs;
  4101 omits the infamous "standard" operation, so this is more appropriate
  4102 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4103 
  4104 * Pure: improved error reporting of simprocs;
  4105 
  4106 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4107 up simprocs;
  4108 
  4109 
  4110 *** Document preparation ***
  4111 
  4112 * uses \par instead of \\ for line breaks in theory text. This may
  4113 shift some page breaks in large documents. To get the old behaviour
  4114 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4115 
  4116 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4117 other packages
  4118 
  4119 * \<euro> now needs package babel/greek instead of marvosym (which
  4120 broke \Rightarrow)
  4121 
  4122 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4123 textcomp package)
  4124 
  4125 
  4126 
  4127 New in Isabelle2002 (March 2002)
  4128 --------------------------------
  4129 
  4130 *** Document preparation ***
  4131 
  4132 * greatly simplified document preparation setup, including more
  4133 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4134 instructive isatool mkdir; users should basically be able to get
  4135 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4136 users may run a separate document processing stage manually like this:
  4137 "isatool usedir -D output HOL Test && isatool document Test/output";
  4138 
  4139 * theory dependency graph may now be incorporated into documents;
  4140 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4141 with \includegraphics of LaTeX;
  4142 
  4143 * proper spacing of consecutive markup elements, especially text
  4144 blocks after section headings;
  4145 
  4146 * support bold style (for single symbols only), input syntax is like
  4147 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4148 
  4149 * \<bullet> is now output as bold \cdot by default, which looks much
  4150 better in printed text;
  4151 
  4152 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4153 note that these symbols are currently unavailable in Proof General /
  4154 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4155 
  4156 * isatool latex no longer depends on changed TEXINPUTS, instead
  4157 isatool document copies the Isabelle style files to the target
  4158 location;
  4159 
  4160 
  4161 *** Isar ***
  4162 
  4163 * Pure/Provers: improved proof by cases and induction;
  4164   - 'case' command admits impromptu naming of parameters (such as
  4165     "case (Suc n)");
  4166   - 'induct' method divinates rule instantiation from the inductive
  4167     claim; no longer requires excessive ?P bindings for proper
  4168     instantiation of cases;
  4169   - 'induct' method properly enumerates all possibilities of set/type
  4170     rules; as a consequence facts may be also passed through *type*
  4171     rules without further ado;
  4172   - 'induct' method now derives symbolic cases from the *rulified*
  4173     rule (before it used to rulify cases stemming from the internal
  4174     atomized version); this means that the context of a non-atomic
  4175     statement becomes is included in the hypothesis, avoiding the
  4176     slightly cumbersome show "PROP ?case" form;
  4177   - 'induct' may now use elim-style induction rules without chaining
  4178     facts, using ``missing'' premises from the goal state; this allows
  4179     rules stemming from inductive sets to be applied in unstructured
  4180     scripts, while still benefitting from proper handling of non-atomic
  4181     statements; NB: major inductive premises need to be put first, all
  4182     the rest of the goal is passed through the induction;
  4183   - 'induct' proper support for mutual induction involving non-atomic
  4184     rule statements (uses the new concept of simultaneous goals, see
  4185     below);
  4186   - append all possible rule selections, but only use the first
  4187     success (no backtracking);
  4188   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4189   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4190   - added 'print_induct_rules' (covered by help item in recent Proof
  4191     General versions);
  4192   - moved induct/cases attributes to Pure, methods to Provers;
  4193   - generic method setup instantiated for FOL and HOL;
  4194 
  4195 * Pure: support multiple simultaneous goal statements, for example
  4196 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4197 meta-level mechanism, this acts as if several individual goals had
  4198 been stated separately; in particular common proof methods need to be
  4199 repeated in order to cover all claims; note that a single elimination
  4200 step is *not* sufficient to establish the two conjunctions, so this
  4201 fails:
  4202 
  4203   assume "A & B" then have A and B ..   (*".." fails*)
  4204 
  4205 better use "obtain" in situations as above; alternative refer to
  4206 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4207 
  4208 * Pure: proper integration with ``locales''; unlike the original
  4209 version by Florian Kammller, Isar locales package high-level proof
  4210 contexts rather than raw logical ones (e.g. we admit to include
  4211 attributes everywhere); operations on locales include merge and
  4212 rename; support for implicit arguments (``structures''); simultaneous
  4213 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4214 some examples;
  4215 
  4216 * Pure: the following commands have been ``localized'', supporting a
  4217 target locale specification "(in name)": 'lemma', 'theorem',
  4218 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4219 stored both within the locale and at the theory level (exported and
  4220 qualified by the locale name);
  4221 
  4222 * Pure: theory goals may now be specified in ``long'' form, with
  4223 ad-hoc contexts consisting of arbitrary locale elements. for example
  4224 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4225 definitions may be given, too); the result is a meta-level rule with
  4226 the context elements being discharged in the obvious way;
  4227 
  4228 * Pure: new proof command 'using' allows to augment currently used
  4229 facts after a goal statement ('using' is syntactically analogous to
  4230 'apply', but acts on the goal's facts only); this allows chained facts
  4231 to be separated into parts given before and after a claim, as in
  4232 ``from a and b have C using d and e <proof>'';
  4233 
  4234 * Pure: renamed "antecedent" case to "rule_context";
  4235 
  4236 * Pure: new 'judgment' command records explicit information about the
  4237 object-logic embedding (used by several tools internally); no longer
  4238 use hard-wired "Trueprop";
  4239 
  4240 * Pure: added 'corollary' command;
  4241 
  4242 * Pure: fixed 'token_translation' command;
  4243 
  4244 * Pure: removed obsolete 'exported' attribute;
  4245 
  4246 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4247 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4248 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4249 
  4250 * Pure: method 'atomize' presents local goal premises as object-level
  4251 statements (atomic meta-level propositions); setup controlled via
  4252 rewrite rules declarations of 'atomize' attribute; example
  4253 application: 'induct' method with proper rule statements in improper
  4254 proof *scripts*;
  4255 
  4256 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4257 now consider the syntactic context of assumptions, giving a better
  4258 chance to get type-inference of the arguments right (this is
  4259 especially important for locales);
  4260 
  4261 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4262 mode;
  4263 
  4264 * Pure/obtain: the formal conclusion "thesis", being marked as
  4265 ``internal'', may no longer be reference directly in the text;
  4266 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4267 situations;
  4268 
  4269 * Pure: generic 'sym' attribute which declares a rule both as pure
  4270 'elim?' and for the 'symmetric' operation;
  4271 
  4272 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4273 text; the fixed correlation with particular command syntax has been
  4274 discontinued;
  4275 
  4276 * Pure: new method 'rules' is particularly well-suited for proof
  4277 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4278 but often produces more compact proof terms with less detours;
  4279 
  4280 * Pure/Provers/classical: simplified integration with pure rule
  4281 attributes and methods; the classical "intro?/elim?/dest?"
  4282 declarations coincide with the pure ones; the "rule" method no longer
  4283 includes classically swapped intros; "intro" and "elim" methods no
  4284 longer pick rules from the context; also got rid of ML declarations
  4285 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4286 INCOMPATIBILITY;
  4287 
  4288 * Provers/classical: attribute 'swapped' produces classical inversions
  4289 of introduction rules;
  4290 
  4291 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4292 rules instead of full simplifier context; 'iff' attribute handles
  4293 conditional rules;
  4294 
  4295 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4296 
  4297 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4298 "(permissive)" option to recover old behavior;
  4299 
  4300 * HOL: 'inductive' no longer features separate (collective) attributes
  4301 for 'intros' (was found too confusing);
  4302 
  4303 * HOL: properly declared induction rules less_induct and
  4304 wf_induct_rule;
  4305 
  4306 
  4307 *** HOL ***
  4308 
  4309 * HOL: moved over to sane numeral syntax; the new policy is as
  4310 follows:
  4311 
  4312   - 0 and 1 are polymorphic constants, which are defined on any
  4313   numeric type (nat, int, real etc.);
  4314 
  4315   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4316   binary representation internally;
  4317 
  4318   - type nat has special constructor Suc, and generally prefers Suc 0
  4319   over 1::nat and Suc (Suc 0) over 2::nat;
  4320 
  4321 This change may cause significant problems of INCOMPATIBILITY; here
  4322 are some hints on converting existing sources:
  4323 
  4324   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4325   entities, so expressions involving "-" (unary or binary minus) need
  4326   to be spaced properly;
  4327 
  4328   - existing occurrences of "1" may need to be constraint "1::nat" or
  4329   even replaced by Suc 0; similar for old "2";
  4330 
  4331   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4332 
  4333   - remove all special provisions on numerals in proofs;
  4334 
  4335 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4336 representation (depends on bin_arith_simps in the default context);
  4337 
  4338 * HOL: symbolic syntax for x^2 (numeral 2);
  4339 
  4340 * HOL: the class of all HOL types is now called "type" rather than
  4341 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4342 in axclass/classes, instance/arities, and (usually rare) occurrences
  4343 in typings (of consts etc.); internally the class is called
  4344 "HOL.type", ML programs should refer to HOLogic.typeS;
  4345 
  4346 * HOL/record package improvements:
  4347   - new derived operations "fields" to build a partial record section,
  4348     "extend" to promote a fixed record to a record scheme, and
  4349     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4350     declared as simp by default;
  4351   - shared operations ("more", "fields", etc.) now need to be always
  4352     qualified) --- potential INCOMPATIBILITY;
  4353   - removed "make_scheme" operations (use "make" with "extend") --
  4354     INCOMPATIBILITY;
  4355   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4356   - provides cases/induct rules for use with corresponding Isar
  4357     methods (for concrete records, record schemes, concrete more
  4358     parts, and schematic more parts -- in that order);
  4359   - internal definitions directly based on a light-weight abstract
  4360     theory of product types over typedef rather than datatype;
  4361 
  4362 * HOL: generic code generator for generating executable ML code from
  4363 specifications; specific support for HOL constructs such as inductive
  4364 datatypes and sets, as well as recursive functions; can be invoked
  4365 via 'generate_code' theory section;
  4366 
  4367 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4368 
  4369 * HOL: consolidated and renamed several theories.  In particular:
  4370         Ord.thy has been absorbed into HOL.thy
  4371         String.thy has been absorbed into List.thy
  4372 
  4373 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4374 (beware of argument permutation!);
  4375 
  4376 * HOL: linorder_less_split superseded by linorder_cases;
  4377 
  4378 * HOL/List: "nodups" renamed to "distinct";
  4379 
  4380 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4381 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4382   - Ex_def has changed, now need to use some_eq_ex
  4383 
  4384 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4385 in this (rare) case use:
  4386 
  4387   delSWrapper "split_all_tac"
  4388   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4389 
  4390 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4391 MAY FAIL;
  4392 
  4393 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4394 Isabelle's type classes, ^ on functions and relations has too general
  4395 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4396 necessary to attach explicit type constraints;
  4397 
  4398 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4399 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4400 renamed accordingly (eg "compI" -> "rel_compI").
  4401 
  4402 * HOL: syntax translations now work properly with numerals and records
  4403 expressions;
  4404 
  4405 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4406 of "lam" -- INCOMPATIBILITY;
  4407 
  4408 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4409 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4410 renamed "Product_Type.unit";
  4411 
  4412 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4413 
  4414 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4415 the "cases" method);
  4416 
  4417 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4418 Florian Kammller);
  4419 
  4420 * HOL/IMP: updated and converted to new-style theory format; several
  4421 parts turned into readable document, with proper Isar proof texts and
  4422 some explanations (by Gerwin Klein);
  4423 
  4424 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4425 
  4426 * HOL-Hyperreal is now a logic image;
  4427 
  4428 
  4429 *** HOLCF ***
  4430 
  4431 * Isar: consts/constdefs supports mixfix syntax for continuous
  4432 operations;
  4433 
  4434 * Isar: domain package adapted to new-style theory format, e.g. see
  4435 HOLCF/ex/Dnat.thy;
  4436 
  4437 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4438 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4439 lift.induct_tac, always use UU instead of Undef;
  4440 
  4441 * HOLCF/IMP: updated and converted to new-style theory;
  4442 
  4443 
  4444 *** ZF ***
  4445 
  4446 * Isar: proper integration of logic-specific tools and packages,
  4447 including theory commands '(co)inductive', '(co)datatype',
  4448 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4449 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4450 
  4451 * theory Main no longer includes AC; for the Axiom of Choice, base
  4452 your theory on Main_ZFC;
  4453 
  4454 * the integer library now covers quotients and remainders, with many
  4455 laws relating division to addition, multiplication, etc.;
  4456 
  4457 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4458 typeless version of the formalism;
  4459 
  4460 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4461 format;
  4462 
  4463 * ZF/Induct: new directory for examples of inductive definitions,
  4464 including theory Multiset for multiset orderings; converted to
  4465 new-style theory format;
  4466 
  4467 * ZF: many new theorems about lists, ordinals, etc.;
  4468 
  4469 
  4470 *** General ***
  4471 
  4472 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4473 variable proof controls level of detail: 0 = no proofs (only oracle
  4474 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4475 also ref manual for further ML interfaces;
  4476 
  4477 * Pure/axclass: removed obsolete ML interface
  4478 goal_subclass/goal_arity;
  4479 
  4480 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4481 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4482 separate tokens, so expressions involving minus need to be spaced
  4483 properly;
  4484 
  4485 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4486 rather than "infixl" or "infixr";
  4487 
  4488 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4489 sort constraint specifications in type inference; e.g. "x::_::foo"
  4490 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4491 type variable);
  4492 
  4493 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4494 control output of nested => (types); the default behavior is
  4495 "type_brackets";
  4496 
  4497 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4498 tokens into AST constants;
  4499 
  4500 * Pure/syntax: prefer later declarations of translations and print
  4501 translation functions; potential INCOMPATIBILITY: need to reverse
  4502 multiple declarations for same syntax element constant;
  4503 
  4504 * Pure/show_hyps reset by default (in accordance to existing Isar
  4505 practice);
  4506 
  4507 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4508 addSafter;
  4509 
  4510 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4511 as well;
  4512 
  4513 * system: tested support for MacOS X; should be able to get Isabelle +
  4514 Proof General to work in a plain Terminal after installing Poly/ML
  4515 (e.g. from the Isabelle distribution area) and GNU bash alone
  4516 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4517 support requires further installations, e.g. from
  4518 http://fink.sourceforge.net/);
  4519 
  4520 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4521 
  4522 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4523 of 40 MB), cf. ML_OPTIONS;
  4524 
  4525 * system: Proof General keywords specification is now part of the
  4526 Isabelle distribution (see etc/isar-keywords.el);
  4527 
  4528 * system: support for persistent Proof General sessions (refrain from
  4529 outdating all loaded theories on startup); user may create writable
  4530 logic images like this: ``isabelle -q HOL Test'';
  4531 
  4532 * system: smart selection of Isabelle process versus Isabelle
  4533 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4534 run both "isabelle" and "Isabelle" even if file names are badly
  4535 damaged (executable inspects the case of the first letter of its own
  4536 name); added separate "isabelle-process" and "isabelle-interface";
  4537 
  4538 * system: refrain from any attempt at filtering input streams; no
  4539 longer support ``8bit'' encoding of old isabelle font, instead proper
  4540 iso-latin characters may now be used; the related isatools
  4541 "symbolinput" and "nonascii" have disappeared as well;
  4542 
  4543 * system: removed old "xterm" interface (the print modes "xterm" and
  4544 "xterm_color" are still available for direct use in a suitable
  4545 terminal);
  4546 
  4547 
  4548 
  4549 New in Isabelle99-2 (February 2001)
  4550 -----------------------------------
  4551 
  4552 *** Overview of INCOMPATIBILITIES ***
  4553 
  4554 * HOL: please note that theories in the Library and elsewhere often use the
  4555 new-style (Isar) format; to refer to their theorems in an ML script you must
  4556 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4557 
  4558 * HOL: inductive package no longer splits induction rule aggressively,
  4559 but only as far as specified by the introductions given; the old
  4560 format may be recovered via ML function complete_split_rule or attribute
  4561 'split_rule (complete)';
  4562 
  4563 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4564 gfp_Tarski to gfp_unfold;
  4565 
  4566 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4567 
  4568 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4569 relation); infix "^^" has been renamed "``"; infix "``" has been
  4570 renamed "`"; "univalent" has been renamed "single_valued";
  4571 
  4572 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4573 operation;
  4574 
  4575 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4576 
  4577 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4578 
  4579 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4580 consequence, it is no longer monotonic wrt. the local goal context
  4581 (which is now passed through the inductive cases);
  4582 
  4583 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4584 \<gg> to \<ggreater>;
  4585 
  4586 
  4587 *** Document preparation ***
  4588 
  4589 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4590 available: are "it" for near math-mode best-style output, "sl" for
  4591 slanted text style, and "tt" for plain type-writer; if no
  4592 \isabellestyle command is given, output is according to slanted
  4593 type-writer);
  4594 
  4595 * support sub/super scripts (for single symbols only), input syntax is
  4596 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4597 
  4598 * some more standard symbols; see Appendix A of the system manual for
  4599 the complete list of symbols defined in isabellesym.sty;
  4600 
  4601 * improved isabelle style files; more abstract symbol implementation
  4602 (should now use \isamath{...} and \isatext{...} in custom symbol
  4603 definitions);
  4604 
  4605 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4606 state; Note that presentation of goal states does not conform to
  4607 actual human-readable proof documents.  Please do not include goal
  4608 states into document output unless you really know what you are doing!
  4609 
  4610 * proper indentation of antiquoted output with proportional LaTeX
  4611 fonts;
  4612 
  4613 * no_document ML operator temporarily disables LaTeX document
  4614 generation;
  4615 
  4616 * isatool unsymbolize tunes sources for plain ASCII communication;
  4617 
  4618 
  4619 *** Isar ***
  4620 
  4621 * Pure: Isar now suffers initial goal statements to contain unbound
  4622 schematic variables (this does not conform to actual readable proof
  4623 documents, due to unpredictable outcome and non-compositional proof
  4624 checking); users who know what they are doing may use schematic goals
  4625 for Prolog-style synthesis of proven results;
  4626 
  4627 * Pure: assumption method (an implicit finishing) now handles actual
  4628 rules as well;
  4629 
  4630 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4631 initial goal, declare "that" only as Pure intro (only for single
  4632 steps); the "that" rule assumption may now be involved in implicit
  4633 finishing, thus ".." becomes a feasible for trivial obtains;
  4634 
  4635 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4636 instance proofs may be performed by "..";
  4637 
  4638 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4639 statements as well;
  4640 
  4641 * Pure: more robust selection of calculational rules;
  4642 
  4643 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4644 rule (as well as the assumption rule);
  4645 
  4646 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4647 lemmas, using the graph browser tool;
  4648 
  4649 * Pure: predict failure of "show" in interactive mode;
  4650 
  4651 * Pure: 'thms_containing' now takes actual terms as arguments;
  4652 
  4653 * HOL: improved method 'induct' --- now handles non-atomic goals
  4654 (potential INCOMPATIBILITY); tuned error handling;
  4655 
  4656 * HOL: cases and induct rules now provide explicit hints about the
  4657 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4658 any remaining facts are inserted into the goal verbatim;
  4659 
  4660 * HOL: local contexts (aka cases) may now contain term bindings as
  4661 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4662 the result to be shown in each case;
  4663 
  4664 * HOL: added 'recdef_tc' command;
  4665 
  4666 * isatool convert assists in eliminating legacy ML scripts;
  4667 
  4668 
  4669 *** HOL ***
  4670 
  4671 * HOL/Library: a collection of generic theories to be used together
  4672 with main HOL; the theory loader path already includes this directory
  4673 by default; the following existing theories have been moved here:
  4674 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4675 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4676 
  4677 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4678 modelling and verification task performed in Isabelle/HOL +
  4679 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4680 
  4681 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4682 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4683 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4684 'domain', this makes the theory consistent with mathematical
  4685 literature;
  4686 
  4687 * HOL basics: added overloaded operations "inverse" and "divide"
  4688 (infix "/"), syntax for generic "abs" operation, generic summation
  4689 operator \<Sum>;
  4690 
  4691 * HOL/typedef: simplified package, provide more useful rules (see also
  4692 HOL/subset.thy);
  4693 
  4694 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4695 now expressed as a proper nested rule (old-style tactic scripts may
  4696 require atomize_strip_tac to cope with non-atomic premises);
  4697 
  4698 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4699 to "split_conv" (old name still available for compatibility);
  4700 
  4701 * HOL: improved concrete syntax for strings (e.g. allows translation
  4702 rules with string literals);
  4703 
  4704 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4705  and Fleuriot's mechanization of analysis, including the transcendental
  4706  functions for the reals;
  4707 
  4708 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4709 
  4710 
  4711 *** CTT ***
  4712 
  4713 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4714 "lam" is displayed as TWO lambda-symbols
  4715 
  4716 * CTT: theory Main now available, containing everything (that is, Bool
  4717 and Arith);
  4718 
  4719 
  4720 *** General ***
  4721 
  4722 * Pure: the Simplifier has been implemented properly as a derived rule
  4723 outside of the actual kernel (at last!); the overall performance
  4724 penalty in practical applications is about 50%, while reliability of
  4725 the Isabelle inference kernel has been greatly improved;
  4726 
  4727 * print modes "brackets" and "no_brackets" control output of nested =>
  4728 (types) and ==> (props); the default behaviour is "brackets";
  4729 
  4730 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4731 as assumptions as well;
  4732 
  4733 * system: support Poly/ML 4.0;
  4734 
  4735 * system: isatool install handles KDE version 1 or 2;
  4736 
  4737 
  4738 
  4739 New in Isabelle99-1 (October 2000)
  4740 ----------------------------------
  4741 
  4742 *** Overview of INCOMPATIBILITIES ***
  4743 
  4744 * HOL: simplification of natural numbers is much changed; to partly
  4745 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4746 issue the following ML commands:
  4747 
  4748   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4749   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4750 
  4751 * HOL: simplification no longer dives into case-expressions; this is
  4752 controlled by "t.weak_case_cong" for each datatype t;
  4753 
  4754 * HOL: nat_less_induct renamed to less_induct;
  4755 
  4756 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4757 fixsome to patch .thy and .ML sources automatically;
  4758 
  4759   select_equality  -> some_equality
  4760   select_eq_Ex     -> some_eq_ex
  4761   selectI2EX       -> someI2_ex
  4762   selectI2         -> someI2
  4763   selectI          -> someI
  4764   select1_equality -> some1_equality
  4765   Eps_sym_eq       -> some_sym_eq_trivial
  4766   Eps_eq           -> some_eq_trivial
  4767 
  4768 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4769 
  4770 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4771 instead);
  4772 
  4773 * HOL: the recursion equations generated by 'recdef' are now called
  4774 f.simps instead of f.rules;
  4775 
  4776 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4777 
  4778 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4779 sometimes be needed;
  4780 
  4781 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4782 
  4783 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4784 
  4785 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4786 product is now "<*>" instead of "Times"; the lexicographic product is
  4787 now "<*lex*>" instead of "**";
  4788 
  4789 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4790 of main HOL, but was unused); better use HOL's datatype package;
  4791 
  4792 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4793 the old syntax may be recovered as follows:
  4794 
  4795   syntax (symbols)
  4796     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4797       (infixl "\\<oplus>" 100)
  4798 
  4799 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4800 
  4801 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4802 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4803 internally;
  4804 
  4805 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4806 changed from A/r to A//r;
  4807 
  4808 * ZF: new treatment of arithmetic (nat & int) may break some old
  4809 proofs;
  4810 
  4811 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4812 rulify -> rule_format, elimify -> elim_format, ...);
  4813 
  4814 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4815 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4816 should have to change intro!! to intro? only); replaced "delrule" by
  4817 "rule del";
  4818 
  4819 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4820 
  4821 * Provers: strengthened force_tac by using new first_best_tac;
  4822 
  4823 * LaTeX document preparation: several changes of isabelle.sty (see
  4824 lib/texinputs);
  4825 
  4826 
  4827 *** Document preparation ***
  4828 
  4829 * formal comments (text blocks etc.) in new-style theories may now
  4830 contain antiquotations of thm/prop/term/typ/text to be presented
  4831 according to latex print mode; concrete syntax is like this:
  4832 @{term[show_types] "f(x) = a + x"};
  4833 
  4834 * isatool mkdir provides easy setup of Isabelle session directories,
  4835 including proper document sources;
  4836 
  4837 * generated LaTeX sources are now deleted after successful run
  4838 (isatool document -c); may retain a copy somewhere else via -D option
  4839 of isatool usedir;
  4840 
  4841 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4842 style files, achieving self-contained LaTeX sources and simplifying
  4843 LaTeX debugging;
  4844 
  4845 * old-style theories now produce (crude) LaTeX output as well;
  4846 
  4847 * browser info session directories are now self-contained (may be put
  4848 on WWW server seperately); improved graphs of nested sessions; removed
  4849 graph for 'all sessions';
  4850 
  4851 * several improvements in isabelle style files; \isabellestyle{it}
  4852 produces fake math mode output; \isamarkupheader is now \section by
  4853 default; see lib/texinputs/isabelle.sty etc.;
  4854 
  4855 
  4856 *** Isar ***
  4857 
  4858 * Isar/Pure: local results and corresponding term bindings are now
  4859 subject to Hindley-Milner polymorphism (similar to ML); this
  4860 accommodates incremental type-inference very nicely;
  4861 
  4862 * Isar/Pure: new derived language element 'obtain' supports
  4863 generalized existence reasoning;
  4864 
  4865 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4866 support accumulation of results, without applying any rules yet;
  4867 useful to collect intermediate results without explicit name
  4868 references, and for use with transitivity rules with more than 2
  4869 premises;
  4870 
  4871 * Isar/Pure: scalable support for case-analysis type proofs: new
  4872 'case' language element refers to local contexts symbolically, as
  4873 produced by certain proof methods; internally, case names are attached
  4874 to theorems as "tags";
  4875 
  4876 * Isar/Pure: theory command 'hide' removes declarations from
  4877 class/type/const name spaces;
  4878 
  4879 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4880 indicate potential overloading;
  4881 
  4882 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4883 
  4884 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4885 "{a,b,c}" instead of {a,b,c};
  4886 
  4887 * Isar/Pure now provides its own version of intro/elim/dest
  4888 attributes; useful for building new logics, but beware of confusion
  4889 with the version in Provers/classical;
  4890 
  4891 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4892 case name 'antecedent';
  4893 
  4894 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4895 to the current context is now done automatically);
  4896 
  4897 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4898 for definining proof methods in ML;
  4899 
  4900 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4901 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4902 most cases, one should have to change intro!! to intro? only);
  4903 replaced "delrule" by "rule del";
  4904 
  4905 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4906 'symmetric' attribute (the latter supercedes [RS sym]);
  4907 
  4908 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4909 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4910 well (including splits);
  4911 
  4912 * Isar/Provers: Simplifier and Classical methods now support all kind
  4913 of modifiers used in the past, including 'cong', 'iff', etc.
  4914 
  4915 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4916 of Simplifier and Classical reasoner);
  4917 
  4918 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4919 now support named cases; major packages (inductive, datatype, primrec,
  4920 recdef) support case names and properly name parameters;
  4921 
  4922 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4923 monotonicity conditions are extracted to be proven at end of
  4924 calculations;
  4925 
  4926 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4927 method anyway;
  4928 
  4929 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4930 split_if split_if_asm; datatype package provides theorems foo.splits =
  4931 foo.split foo.split_asm for each datatype;
  4932 
  4933 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4934 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4935 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4936 use "(cases (simplified))" method in proper proof texts);
  4937 
  4938 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4939 
  4940 * Isar: names of theorems etc. may be natural numbers as well;
  4941 
  4942 * Isar: 'pr' command: optional arguments for goals_limit and
  4943 ProofContext.prems_limit; no longer prints theory contexts, but only
  4944 proof states;
  4945 
  4946 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4947 additional print modes to be specified; e.g. "pr(latex)" will print
  4948 proof state according to the Isabelle LaTeX style;
  4949 
  4950 * Isar: improved support for emulating tactic scripts, including proof
  4951 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4952 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4953 (for HOL datatypes);
  4954 
  4955 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4956 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4957 'proof method scripts' have to be in depth-first order;
  4958 
  4959 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4960 
  4961 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4962 should instead use individual commands for printing items
  4963 (print_commands, print_methods etc.);
  4964 
  4965 * Isar: added 'nothing' --- the empty list of theorems;
  4966 
  4967 
  4968 *** HOL ***
  4969 
  4970 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4971 corresponding virtual machine and a specification of its bytecode
  4972 verifier and a lightweight bytecode verifier, including proofs of
  4973 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4974 Cornelia Pusch (see also the homepage of project Bali at
  4975 http://isabelle.in.tum.de/Bali/);
  4976 
  4977 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4978 Clemens Ballarin;
  4979 
  4980 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4981 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4982 Rasmussen;
  4983 
  4984 * HOL/Lattice: fundamental concepts of lattice theory and order
  4985 structures, including duals, properties of bounds versus algebraic
  4986 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4987 Theorem for complete lattices etc.; may also serve as a demonstration
  4988 for abstract algebraic reasoning using axiomatic type classes, and
  4989 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4990 
  4991 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4992 von Oheimb;
  4993 
  4994 * HOL/IMPP: extension of IMP with local variables and mutually
  4995 recursive procedures, by David von Oheimb;
  4996 
  4997 * HOL/Lambda: converted into new-style theory and document;
  4998 
  4999 * HOL/ex/Multiquote: example of multiple nested quotations and
  5000 anti-quotations -- basically a generalized version of de-Bruijn
  5001 representation; very useful in avoiding lifting of operations;
  5002 
  5003 * HOL/record: added general record equality rule to simpset; fixed
  5004 select-update simplification procedure to handle extended records as
  5005 well; admit "r" as field name;
  5006 
  5007 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  5008 other numeric types and also as the identity of groups, rings, etc.;
  5009 
  5010 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  5011 Types nat and int belong to this axclass;
  5012 
  5013 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  5014    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  5015    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  5016   two terms #m*u and #n*u are replaced by #(m+n)*u
  5017     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  5018   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  5019     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  5020 
  5021 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  5022 powerful prover for predicate logic but knows nothing of clasets; see
  5023 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  5024 
  5025 * HOL: new version of "case_tac" subsumes both boolean case split and
  5026 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  5027 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  5028 
  5029 * HOL: simplification no longer dives into case-expressions: only the
  5030 selector expression is simplified, but not the remaining arms; to
  5031 enable full simplification of case-expressions for datatype t, you may
  5032 remove t.weak_case_cong from the simpset, either globally (Delcongs
  5033 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  5034 
  5035 * HOL/recdef: the recursion equations generated by 'recdef' for
  5036 function 'f' are now called f.simps instead of f.rules; if all
  5037 termination conditions are proved automatically, these simplification
  5038 rules are added to the simpset, as in primrec; rules may be named
  5039 individually as well, resulting in a separate list of theorems for
  5040 each equation;
  5041 
  5042 * HOL/While is a new theory that provides a while-combinator. It
  5043 permits the definition of tail-recursive functions without the
  5044 provision of a termination measure. The latter is necessary once the
  5045 invariant proof rule for while is applied.
  5046 
  5047 * HOL: new (overloaded) notation for the set of elements below/above
  5048 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5049 
  5050 * HOL: theorems impI, allI, ballI bound as "strip";
  5051 
  5052 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5053 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5054 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5055 
  5056 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5057 
  5058 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5059 main HOL, but was unused);
  5060 
  5061 * HOL: fewer consts declared as global (e.g. have to refer to
  5062 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5063 
  5064 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5065 in case of overlap with user translations (e.g. judgements over
  5066 tuples); (note that the underlying logical represenation is still
  5067 bogus);
  5068 
  5069 
  5070 *** ZF ***
  5071 
  5072 * ZF: simplification automatically cancels common terms in arithmetic
  5073 expressions over nat and int;
  5074 
  5075 * ZF: new treatment of nat to minimize type-checking: all operators
  5076 coerce their operands to a natural number using the function natify,
  5077 making the algebraic laws unconditional;
  5078 
  5079 * ZF: as above, for int: operators coerce their operands to an integer
  5080 using the function intify;
  5081 
  5082 * ZF: the integer library now contains many of the usual laws for the
  5083 orderings, including $<=, and monotonicity laws for $+ and $*;
  5084 
  5085 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5086 simplification;
  5087 
  5088 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5089 to the simplifier and classical reasoner simultaneously;
  5090 
  5091 
  5092 *** General ***
  5093 
  5094 * Provers: blast_tac now handles actual object-logic rules as
  5095 assumptions; note that auto_tac uses blast_tac internally as well;
  5096 
  5097 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5098 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5099 
  5100 * Provers: delrules now handles destruct rules as well (no longer need
  5101 explicit make_elim);
  5102 
  5103 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5104   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5105 use instead the strong form,
  5106   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5107 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5108 from destruct-rules;
  5109 
  5110 * Provers: Simplifier.easy_setup provides a fast path to basic
  5111 Simplifier setup for new object-logics;
  5112 
  5113 * Pure: AST translation rules no longer require constant head on LHS;
  5114 
  5115 * Pure: improved name spaces: ambiguous output is qualified; support
  5116 for hiding of names;
  5117 
  5118 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5119 XSYMBOL_HOME; no longer need to do manual configuration in most
  5120 situations;
  5121 
  5122 * system: compression of ML heaps images may now be controlled via -c
  5123 option of isabelle and isatool usedir (currently only observed by
  5124 Poly/ML);
  5125 
  5126 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5127 useful for remote X11);
  5128 
  5129 * system: provide TAGS file for Isabelle sources;
  5130 
  5131 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5132 order;
  5133 
  5134 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5135 timing flag supersedes proof_timing and Toplevel.trace;
  5136 
  5137 * ML: new combinators |>> and |>>> for incremental transformations
  5138 with secondary results (e.g. certain theory extensions):
  5139 
  5140 * ML: PureThy.add_defs gets additional argument to indicate potential
  5141 overloading (usually false);
  5142 
  5143 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5144 results;
  5145 
  5146 
  5147 
  5148 New in Isabelle99 (October 1999)
  5149 --------------------------------
  5150 
  5151 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5152 
  5153 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5154 are no longer simplified.  (This allows the simplifier to unfold recursive
  5155 functional programs.)  To restore the old behaviour, declare
  5156 
  5157     Delcongs [if_weak_cong];
  5158 
  5159 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5160 complement;
  5161 
  5162 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5163 
  5164 * HOL/datatype: mutual_induct_tac no longer exists --
  5165   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5166 
  5167 * HOL/typedef: fixed type inference for representing set; type
  5168 arguments now have to occur explicitly on the rhs as type constraints;
  5169 
  5170 * ZF: The con_defs part of an inductive definition may no longer refer
  5171 to constants declared in the same theory;
  5172 
  5173 * HOL, ZF: the function mk_cases, generated by the inductive
  5174 definition package, has lost an argument.  To simplify its result, it
  5175 uses the default simpset instead of a supplied list of theorems.
  5176 
  5177 * HOL/List: the constructors of type list are now Nil and Cons;
  5178 
  5179 * Simplifier: the type of the infix ML functions
  5180         setSSolver addSSolver setSolver addSolver
  5181 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5182 for packaging solvers. A solver is created via
  5183         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5184 where the string argument is only a comment.
  5185 
  5186 
  5187 *** Proof tools ***
  5188 
  5189 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5190 decision procedure for linear arithmetic. Currently it is used for
  5191 types `nat', `int', and `real' in HOL (see below); it can, should and
  5192 will be instantiated for other types and logics as well.
  5193 
  5194 * The simplifier now accepts rewrite rules with flexible heads, eg
  5195      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5196   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5197   matching.
  5198 
  5199 
  5200 *** General ***
  5201 
  5202 * New Isabelle/Isar subsystem provides an alternative to traditional
  5203 tactical theorem proving; together with the ProofGeneral/isar user
  5204 interface it offers an interactive environment for developing human
  5205 readable proof documents (Isar == Intelligible semi-automated
  5206 reasoning); for further information see isatool doc isar-ref,
  5207 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5208 
  5209 * improved and simplified presentation of theories: better HTML markup
  5210 (including colors), graph views in several sizes; isatool usedir now
  5211 provides a proper interface for user theories (via -P option); actual
  5212 document preparation based on (PDF)LaTeX is available as well (for
  5213 new-style theories only); see isatool doc system for more information;
  5214 
  5215 * native support for Proof General, both for classic Isabelle and
  5216 Isabelle/Isar;
  5217 
  5218 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5219 using the graph browser tool;
  5220 
  5221 * Isabelle manuals now also available as PDF;
  5222 
  5223 * theory loader rewritten from scratch (may not be fully
  5224 bug-compatible); old loadpath variable has been replaced by show_path,
  5225 add_path, del_path, reset_path functions; new operations such as
  5226 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5227 isatool doc ref);
  5228 
  5229 * improved isatool install: option -k creates KDE application icon,
  5230 option -p DIR installs standalone binaries;
  5231 
  5232 * added ML_PLATFORM setting (useful for cross-platform installations);
  5233 more robust handling of platform specific ML images for SML/NJ;
  5234 
  5235 * the settings environment is now statically scoped, i.e. it is never
  5236 created again in sub-processes invoked from isabelle, isatool, or
  5237 Isabelle;
  5238 
  5239 * path element specification '~~' refers to '$ISABELLE_HOME';
  5240 
  5241 * in locales, the "assumes" and "defines" parts may be omitted if
  5242 empty;
  5243 
  5244 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5245 long arrows);
  5246 
  5247 * new print_mode "HTML";
  5248 
  5249 * new flag show_tags controls display of tags of theorems (which are
  5250 basically just comments that may be attached by some tools);
  5251 
  5252 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5253 mode and goal output format:
  5254 
  5255 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5256 244c244
  5257 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5258 ---
  5259 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5260 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5261 181c181
  5262 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5263 ---
  5264 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5265 
  5266 * function bind_thms stores lists of theorems (cf. bind_thm);
  5267 
  5268 * new shorthand tactics ftac, eatac, datac, fatac;
  5269 
  5270 * qed (and friends) now accept "" as result name; in that case the
  5271 theorem is not stored, but proper checks and presentation of the
  5272 result still apply;
  5273 
  5274 * theorem database now also indexes constants "Trueprop", "all",
  5275 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5276 
  5277 
  5278 *** HOL ***
  5279 
  5280 ** HOL arithmetic **
  5281 
  5282 * There are now decision procedures for linear arithmetic over nat and
  5283 int:
  5284 
  5285 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5286 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5287 are treated as atomic; subformulae not involving type `nat' or `int'
  5288 are ignored; quantified subformulae are ignored unless they are
  5289 positive universal or negative existential. The tactic has to be
  5290 invoked by hand and can be a little bit slow. In particular, the
  5291 running time is exponential in the number of occurrences of `min' and
  5292 `max', and `-' on `nat'.
  5293 
  5294 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5295 (negated) (in)equalities among the premises and the conclusion into
  5296 account (i.e. no compound formulae) and does not know about `min' and
  5297 `max', and `-' on `nat'. It is fast and is used automatically by the
  5298 simplifier.
  5299 
  5300 NB: At the moment, these decision procedures do not cope with mixed
  5301 nat/int formulae where the two parts interact, such as `m < n ==>
  5302 int(m) < int(n)'.
  5303 
  5304 * HOL/Numeral provides a generic theory of numerals (encoded
  5305 efficiently as bit strings); setup for types nat/int/real is in place;
  5306 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5307 int, existing theories and proof scripts may require a few additional
  5308 type constraints;
  5309 
  5310 * integer division and remainder can now be performed on constant
  5311 arguments;
  5312 
  5313 * many properties of integer multiplication, division and remainder
  5314 are now available;
  5315 
  5316 * An interface to the Stanford Validity Checker (SVC) is available through the
  5317 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5318 are proved automatically.  SVC must be installed separately, and its results
  5319 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5320 invocation of the underlying oracle).  For SVC see
  5321   http://verify.stanford.edu/SVC
  5322 
  5323 * IsaMakefile: the HOL-Real target now builds an actual image;
  5324 
  5325 
  5326 ** HOL misc **
  5327 
  5328 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5329 (in Isabelle/Isar) -- by Gertrud Bauer;
  5330 
  5331 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5332 analysis for assembly languages with subtypes;
  5333 
  5334 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5335 -- avoids syntactic ambiguities and treats state, transition, and
  5336 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5337 changed syntax and (many) tactics;
  5338 
  5339 * HOL/inductive: Now also handles more general introduction rules such
  5340   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5341   theorems are now maintained within the theory (maintained via the
  5342   "mono" attribute);
  5343 
  5344 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5345   (using function types) such as
  5346 
  5347   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5348 
  5349 * HOL/record: record_simproc (part of the default simpset) takes care
  5350 of selectors applied to updated records; record_split_tac is no longer
  5351 part of the default claset; update_defs may now be removed from the
  5352 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5353 
  5354   claset_ref () := claset() addSWrapper record_split_wrapper;
  5355   Delsimprocs [record_simproc]
  5356 
  5357 * HOL/typedef: fixed type inference for representing set; type
  5358 arguments now have to occur explicitly on the rhs as type constraints;
  5359 
  5360 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5361 names rather than an ML expression;
  5362 
  5363 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5364 supplied later.  Program schemes can be defined, such as
  5365     "While B C s = (if B s then While B C (C s) else s)"
  5366 where the well-founded relation can be chosen after B and C have been given.
  5367 
  5368 * HOL/List: the constructors of type list are now Nil and Cons;
  5369 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5370 course, ML tools referring to List.list.op # etc. have to be adapted;
  5371 
  5372 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5373 disabled by default; run isabelle with option -m HOL to get back to
  5374 the original Gordon/HOL-style output;
  5375 
  5376 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5377 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5378 
  5379 * HOL basic syntax simplified (more orthogonal): all variants of
  5380 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5381 Eps operator is provided as well: "SOME x. P[x]";
  5382 
  5383 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5384 
  5385 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5386 thus available for user theories;
  5387 
  5388 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5389 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5390 time;
  5391 
  5392 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5393 several times and then mp;
  5394 
  5395 
  5396 *** LK ***
  5397 
  5398 * the notation <<...>> is now available as a notation for sequences of
  5399 formulas;
  5400 
  5401 * the simplifier is now installed
  5402 
  5403 * the axiom system has been generalized (thanks to Soren Heilmann)
  5404 
  5405 * the classical reasoner now has a default rule database
  5406 
  5407 
  5408 *** ZF ***
  5409 
  5410 * new primrec section allows primitive recursive functions to be given
  5411 directly (as in HOL) over datatypes and the natural numbers;
  5412 
  5413 * new tactics induct_tac and exhaust_tac for induction (or case
  5414 analysis) over datatypes and the natural numbers;
  5415 
  5416 * the datatype declaration of type T now defines the recursor T_rec;
  5417 
  5418 * simplification automatically does freeness reasoning for datatype
  5419 constructors;
  5420 
  5421 * automatic type-inference, with AddTCs command to insert new
  5422 type-checking rules;
  5423 
  5424 * datatype introduction rules are now added as Safe Introduction rules
  5425 to the claset;
  5426 
  5427 * the syntax "if P then x else y" is now available in addition to
  5428 if(P,x,y);
  5429 
  5430 
  5431 *** Internal programming interfaces ***
  5432 
  5433 * tuned simplifier trace output; new flag debug_simp;
  5434 
  5435 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5436 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5437 
  5438 * AxClass.axclass_tac lost the theory argument;
  5439 
  5440 * tuned current_goals_markers semantics: begin / end goal avoids
  5441 printing empty lines;
  5442 
  5443 * removed prs and prs_fn hook, which was broken because it did not
  5444 include \n in its semantics, forcing writeln to add one
  5445 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5446 string -> unit if you really want to output text without newline;
  5447 
  5448 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5449 plain output, interface builders may have to enable 'isabelle_font'
  5450 mode to get Isabelle font glyphs as before;
  5451 
  5452 * refined token_translation interface; INCOMPATIBILITY: output length
  5453 now of type real instead of int;
  5454 
  5455 * theory loader actions may be traced via new ThyInfo.add_hook
  5456 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5457 your own database of information attached to *whole* theories -- as
  5458 opposed to intra-theory data slots offered via TheoryDataFun;
  5459 
  5460 * proper handling of dangling sort hypotheses (at last!);
  5461 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5462 extra sort hypotheses that can be witnessed from the type signature;
  5463 the force_strip_shyps flag is gone, any remaining shyps are simply
  5464 left in the theorem (with a warning issued by strip_shyps_warning);
  5465 
  5466 
  5467 
  5468 New in Isabelle98-1 (October 1998)
  5469 ----------------------------------
  5470 
  5471 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5472 
  5473 * several changes of automated proof tools;
  5474 
  5475 * HOL: major changes to the inductive and datatype packages, including
  5476 some minor incompatibilities of theory syntax;
  5477 
  5478 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5479 called `inj_on';
  5480 
  5481 * HOL: removed duplicate thms in Arith:
  5482   less_imp_add_less  should be replaced by  trans_less_add1
  5483   le_imp_add_le      should be replaced by  trans_le_add1
  5484 
  5485 * HOL: unary minus is now overloaded (new type constraints may be
  5486 required);
  5487 
  5488 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5489 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5490 now taken as an integer constant.
  5491 
  5492 * Pure: ML function 'theory_of' renamed to 'theory';
  5493 
  5494 
  5495 *** Proof tools ***
  5496 
  5497 * Simplifier:
  5498   1. Asm_full_simp_tac is now more aggressive.
  5499      1. It will sometimes reorient premises if that increases their power to
  5500         simplify.
  5501      2. It does no longer proceed strictly from left to right but may also
  5502         rotate premises to achieve further simplification.
  5503      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5504      old Asm_full_simp_tac in that it does not rotate premises.
  5505   2. The simplifier now knows a little bit about nat-arithmetic.
  5506 
  5507 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5508 allows for selected deletion of wrappers, by introduction of names for
  5509 wrapper functionals.  This implies that addbefore, addSbefore,
  5510 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5511 and that adding two tactics with the same name overwrites the first
  5512 one (emitting a warning).
  5513   type wrapper = (int -> tactic) -> (int -> tactic)
  5514   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5515   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5516   delWrapper, delSWrapper: claset *  string            -> claset
  5517   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5518 
  5519 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5520 semantics; addbefore now affects only the unsafe part of step_tac
  5521 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5522 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5523 by Force_tac;
  5524 
  5525 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5526 compWrapper; added safe wrapper (and access functions for it);
  5527 
  5528 * HOL/split_all_tac is now much faster and fails if there is nothing
  5529 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5530 and the names of the automatically generated variables have changed.
  5531 split_all_tac has moved within claset() from unsafe wrappers to safe
  5532 wrappers, which means that !!-bound variables are split much more
  5533 aggressively, and safe_tac and clarify_tac now split such variables.
  5534 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5535 Note: the same holds for record_split_tac, which does the job of
  5536 split_all_tac for record fields.
  5537 
  5538 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5539 permanently to the default simpset using Addsplits just like
  5540 Addsimps. They can be removed via Delsplits just like
  5541 Delsimps. Lower-case versions are also available.
  5542 
  5543 * HOL/Simplifier: The rule split_if is now part of the default
  5544 simpset. This means that the simplifier will eliminate all occurrences
  5545 of if-then-else in the conclusion of a goal. To prevent this, you can
  5546 either remove split_if completely from the default simpset by
  5547 `Delsplits [split_if]' or remove it in a specific call of the
  5548 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5549 other case splitting rules to/from the default simpset: every datatype
  5550 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5551 t is the name of the datatype).
  5552 
  5553 * Classical reasoner / Simplifier combination: new force_tac (and
  5554 derivatives Force_tac, force) combines rewriting and classical
  5555 reasoning (and whatever other tools) similarly to auto_tac, but is
  5556 aimed to solve the given subgoal completely.
  5557 
  5558 
  5559 *** General ***
  5560 
  5561 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5562 and `goalw': the theory is no longer needed as an explicit argument -
  5563 the current theory context is used; assumptions are no longer returned
  5564 at the ML-level unless one of them starts with ==> or !!; it is
  5565 recommended to convert to these new commands using isatool fixgoal
  5566 (backup your sources first!);
  5567 
  5568 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5569 the current theory context, and 'theory' to lookup stored theories;
  5570 
  5571 * new theory section 'locale' for declaring constants, assumptions and
  5572 definitions that have local scope;
  5573 
  5574 * new theory section 'nonterminals' for purely syntactic types;
  5575 
  5576 * new theory section 'setup' for generic ML setup functions
  5577 (e.g. package initialization);
  5578 
  5579 * the distribution now includes Isabelle icons: see
  5580 lib/logo/isabelle-{small,tiny}.xpm;
  5581 
  5582 * isatool install - install binaries with absolute references to
  5583 ISABELLE_HOME/bin;
  5584 
  5585 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5586 
  5587 * print mode 'emacs' reserved for Isamode;
  5588 
  5589 * support multiple print (ast) translations per constant name;
  5590 
  5591 * theorems involving oracles are now printed with a suffixed [!];
  5592 
  5593 
  5594 *** HOL ***
  5595 
  5596 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5597 
  5598 * HOL/inductive package reorganized and improved: now supports mutual
  5599 definitions such as
  5600 
  5601   inductive EVEN ODD
  5602     intrs
  5603       null "0 : EVEN"
  5604       oddI "n : EVEN ==> Suc n : ODD"
  5605       evenI "n : ODD ==> Suc n : EVEN"
  5606 
  5607 new theorem list "elims" contains an elimination rule for each of the
  5608 recursive sets; inductive definitions now handle disjunctive premises
  5609 correctly (also ZF);
  5610 
  5611 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5612 "mutual_induct" no longer exists - the induction rule is always
  5613 contained in "induct";
  5614 
  5615 
  5616 * HOL/datatype package re-implemented and greatly improved: now
  5617 supports mutually recursive datatypes such as
  5618 
  5619   datatype
  5620     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5621             | SUM ('a aexp) ('a aexp)
  5622             | DIFF ('a aexp) ('a aexp)
  5623             | NUM 'a
  5624   and
  5625     'a bexp = LESS ('a aexp) ('a aexp)
  5626             | AND ('a bexp) ('a bexp)
  5627             | OR ('a bexp) ('a bexp)
  5628 
  5629 as well as indirectly recursive datatypes such as
  5630 
  5631   datatype
  5632     ('a, 'b) term = Var 'a
  5633                   | App 'b ((('a, 'b) term) list)
  5634 
  5635 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5636 induction on mutually / indirectly recursive datatypes.
  5637 
  5638 Primrec equations are now stored in theory and can be accessed via
  5639 <function_name>.simps.
  5640 
  5641 INCOMPATIBILITIES:
  5642 
  5643   - Theories using datatypes must now have theory Datatype as an
  5644     ancestor.
  5645   - The specific <typename>.induct_tac no longer exists - use the
  5646     generic induct_tac instead.
  5647   - natE has been renamed to nat.exhaust - use exhaust_tac
  5648     instead of res_inst_tac ... natE. Note that the variable
  5649     names in nat.exhaust differ from the names in natE, this
  5650     may cause some "fragile" proofs to fail.
  5651   - The theorems split_<typename>_case and split_<typename>_case_asm
  5652     have been renamed to <typename>.split and <typename>.split_asm.
  5653   - Since default sorts of type variables are now handled correctly,
  5654     some datatype definitions may have to be annotated with explicit
  5655     sort constraints.
  5656   - Primrec definitions no longer require function name and type
  5657     of recursive argument.
  5658 
  5659 Consider using isatool fixdatatype to adapt your theories and proof
  5660 scripts to the new package (backup your sources first!).
  5661 
  5662 
  5663 * HOL/record package: considerably improved implementation; now
  5664 includes concrete syntax for record types, terms, updates; theorems
  5665 for surjective pairing and splitting !!-bound record variables; proof
  5666 support is as follows:
  5667 
  5668   1) standard conversions (selectors or updates applied to record
  5669 constructor terms) are part of the standard simpset;
  5670 
  5671   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5672 made part of standard simpset and claset via addIffs;
  5673 
  5674   3) a tactic for record field splitting (record_split_tac) is part of
  5675 the standard claset (addSWrapper);
  5676 
  5677 To get a better idea about these rules you may retrieve them via
  5678 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5679 the name of your record type.
  5680 
  5681 The split tactic 3) conceptually simplifies by the following rule:
  5682 
  5683   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5684 
  5685 Thus any record variable that is bound by meta-all will automatically
  5686 blow up into some record constructor term, consequently the
  5687 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5688 solve record problems automatically.
  5689 
  5690 
  5691 * reorganized the main HOL image: HOL/Integ and String loaded by
  5692 default; theory Main includes everything;
  5693 
  5694 * automatic simplification of integer sums and comparisons, using cancellation;
  5695 
  5696 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5697 
  5698 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5699 
  5700 * many new identities for unions, intersections, set difference, etc.;
  5701 
  5702 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5703 called split_if, split_split, split_sum_case and split_nat_case (to go
  5704 with add/delsplits);
  5705 
  5706 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5707 (?x::unit) = (); this is made part of the default simpset, which COULD
  5708 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5709 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5710 unit_abs_eta_conv is added in order to counter the effect of
  5711 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5712 %u.f();
  5713 
  5714 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5715 makes more sense);
  5716 
  5717 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5718   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5719   disjointness reasoning but breaking a few old proofs.
  5720 
  5721 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5722 to 'converse' from 'inverse' (for compatibility with ZF and some
  5723 literature);
  5724 
  5725 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5726 the well-founded relation;
  5727 
  5728 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5729     Compl A.  The "Compl" syntax remains available as input syntax for this
  5730     release ONLY.
  5731 
  5732 * HOL/Update: new theory of function updates:
  5733     f(a:=b) == %x. if x=a then b else f x
  5734 may also be iterated as in f(a:=b,c:=d,...);
  5735 
  5736 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5737 
  5738 * HOL/List:
  5739   - new function list_update written xs[i:=v] that updates the i-th
  5740     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5741   - new function `upt' written [i..j(] which generates the list
  5742     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5743     bound write [i..j], which is a shorthand for [i..j+1(].
  5744   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5745 
  5746 * HOL/Arith:
  5747   - removed 'pred' (predecessor) function;
  5748   - generalized some theorems about n-1;
  5749   - many new laws about "div" and "mod";
  5750   - new laws about greatest common divisors (see theory ex/Primes);
  5751 
  5752 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5753 instead of "inverse";
  5754 
  5755 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5756   of the multiset ordering;
  5757 
  5758 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5759   (not included by default);
  5760 
  5761 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5762 
  5763 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5764   programs, i.e. different program variables may have different types.
  5765 
  5766 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5767   [previously, this check worked only if the rewrite rule was unconditional]
  5768   Now rew can involve either definitions or equalities (either == or =).
  5769 
  5770 
  5771 *** ZF ***
  5772 
  5773 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5774   only the theorems proved on ZF.ML;
  5775 
  5776 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5777   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5778   disjointness reasoning but breaking a few old proofs.
  5779 
  5780 * ZF/Update: new theory of function updates
  5781     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5782   may also be iterated as in f(a:=b,c:=d,...);
  5783 
  5784 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5785 
  5786 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5787   [previously, this check worked only if the rewrite rule was unconditional]
  5788   Now rew can involve either definitions or equalities (either == or =).
  5789 
  5790 * case_tac provided for compatibility with HOL
  5791     (like the old excluded_middle_tac, but with subgoals swapped)
  5792 
  5793 
  5794 *** Internal programming interfaces ***
  5795 
  5796 * Pure: several new basic modules made available for general use, see
  5797 also src/Pure/README;
  5798 
  5799 * improved the theory data mechanism to support encapsulation (data
  5800 kind name replaced by private Object.kind, acting as authorization
  5801 key); new type-safe user interface via functor TheoryDataFun; generic
  5802 print_data function becomes basically useless;
  5803 
  5804 * removed global_names compatibility flag -- all theory declarations
  5805 are qualified by default;
  5806 
  5807 * module Pure/Syntax now offers quote / antiquote translation
  5808 functions (useful for Hoare logic etc. with implicit dependencies);
  5809 see HOL/ex/Antiquote for an example use;
  5810 
  5811 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5812 cterm -> thm;
  5813 
  5814 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5815 subgoal;
  5816 
  5817 * Display.print_goals function moved to Locale.print_goals;
  5818 
  5819 * standard print function for goals supports current_goals_markers
  5820 variable for marking begin of proof, end of proof, start of goal; the
  5821 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5822 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5823 for example;
  5824 
  5825 
  5826 
  5827 New in Isabelle98 (January 1998)
  5828 --------------------------------
  5829 
  5830 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5831 
  5832 * changed lexical syntax of terms / types: dots made part of long
  5833 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5834 
  5835 * simpset (and claset) reference variable replaced by functions
  5836 simpset / simpset_ref;
  5837 
  5838 * no longer supports theory aliases (via merge) and non-trivial
  5839 implicit merge of thms' signatures;
  5840 
  5841 * most internal names of constants changed due to qualified names;
  5842 
  5843 * changed Pure/Sequence interface (see Pure/seq.ML);
  5844 
  5845 
  5846 *** General Changes ***
  5847 
  5848 * hierachically structured name spaces (for consts, types, axms, thms
  5849 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5850 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5851 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5852 long_names for fully qualified output names; NOTE: ML programs
  5853 (special tactics, packages etc.) referring to internal names may have
  5854 to be adapted to cope with fully qualified names; in case of severe
  5855 backward campatibility problems try setting 'global_names' at compile
  5856 time to have enrything declared within a flat name space; one may also
  5857 fine tune name declarations in theories via the 'global' and 'local'
  5858 section;
  5859 
  5860 * reimplemented the implicit simpset and claset using the new anytype
  5861 data filed in signatures; references simpset:simpset ref etc. are
  5862 replaced by functions simpset:unit->simpset and
  5863 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5864 to patch your ML files accordingly;
  5865 
  5866 * HTML output now includes theory graph data for display with Java
  5867 applet or isatool browser; data generated automatically via isatool
  5868 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5869 
  5870 * defs may now be conditional; improved rewrite_goals_tac to handle
  5871 conditional equations;
  5872 
  5873 * defs now admits additional type arguments, using TYPE('a) syntax;
  5874 
  5875 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5876 creates a new theory node; implicit merge of thms' signatures is
  5877 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5878 transfer:theory->thm->thm in (rare) cases;
  5879 
  5880 * improved handling of draft signatures / theories; draft thms (and
  5881 ctyps, cterms) are automatically promoted to real ones;
  5882 
  5883 * slightly changed interfaces for oracles: admit many per theory, named
  5884 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5885 
  5886 * print_goals: optional output of const types (set show_consts and
  5887 show_types);
  5888 
  5889 * improved output of warnings (###) and errors (***);
  5890 
  5891 * subgoal_tac displays a warning if the new subgoal has type variables;
  5892 
  5893 * removed old README and Makefiles;
  5894 
  5895 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5896 
  5897 * removed obsolete init_pps and init_database;
  5898 
  5899 * deleted the obsolete tactical STATE, which was declared by
  5900     fun STATE tacfun st = tacfun st st;
  5901 
  5902 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5903 (which abbreviates $HOME);
  5904 
  5905 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5906 use isatool fixseq to adapt your ML programs (this works for fully
  5907 qualified references to the Sequence structure only!);
  5908 
  5909 * use_thy no longer requires writable current directory; it always
  5910 reloads .ML *and* .thy file, if either one is out of date;
  5911 
  5912 
  5913 *** Classical Reasoner ***
  5914 
  5915 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5916 tactics that use classical reasoning to simplify a subgoal without
  5917 splitting it into several subgoals;
  5918 
  5919 * Safe_tac: like safe_tac but uses the default claset;
  5920 
  5921 
  5922 *** Simplifier ***
  5923 
  5924 * added simplification meta rules:
  5925     (asm_)(full_)simplify: simpset -> thm -> thm;
  5926 
  5927 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5928 logics (again);
  5929 
  5930 * added prems argument to simplification procedures;
  5931 
  5932 * HOL, FOL, ZF: added infix function `addsplits':
  5933   instead of `<simpset> setloop (split_tac <thms>)'
  5934   you can simply write `<simpset> addsplits <thms>'
  5935 
  5936 
  5937 *** Syntax ***
  5938 
  5939 * TYPE('a) syntax for type reflection terms;
  5940 
  5941 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5942 
  5943 * pretty printer: changed order of mixfix annotation preference (again!);
  5944 
  5945 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5946 
  5947 
  5948 *** HOL ***
  5949 
  5950 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5951   with `addloop' of the simplifier to faciliate case splitting in premises.
  5952 
  5953 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5954 
  5955 * HOL/Auth: new protocol proofs including some for the Internet
  5956   protocol TLS;
  5957 
  5958 * HOL/Map: new theory of `maps' a la VDM;
  5959 
  5960 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5961 cancelling out common nat summands from =, <, <= (in)equalities, or
  5962 differences; simplification procedures nat_cancel_factor for
  5963 cancelling common factor from =, <, <= (in)equalities over natural
  5964 sums; nat_cancel contains both kinds of procedures, it is installed by
  5965 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5966 
  5967 * HOL/simplifier: terms of the form
  5968   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5969   are rewritten to
  5970   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5971   and those of the form
  5972   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5973   are rewritten to
  5974   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5975 
  5976 * HOL/datatype
  5977   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5978 
  5979   P(t_case f1 ... fn x) =
  5980      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5981         ...
  5982        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5983      )
  5984 
  5985   and a theorem `split_t_case_asm' of the form
  5986 
  5987   P(t_case f1 ... fn x) =
  5988     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5989         ...
  5990        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5991      )
  5992   which can be added to a simpset via `addsplits'. The existing theorems
  5993   expand_list_case and expand_option_case have been renamed to
  5994   split_list_case and split_option_case.
  5995 
  5996 * HOL/Arithmetic:
  5997   - `pred n' is automatically converted to `n-1'.
  5998     Users are strongly encouraged not to use `pred' any longer,
  5999     because it will disappear altogether at some point.
  6000   - Users are strongly encouraged to write "0 < n" rather than
  6001     "n ~= 0". Theorems and proof tools have been modified towards this
  6002     `standard'.
  6003 
  6004 * HOL/Lists:
  6005   the function "set_of_list" has been renamed "set" (and its theorems too);
  6006   the function "nth" now takes its arguments in the reverse order and
  6007   has acquired the infix notation "!" as in "xs!n".
  6008 
  6009 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  6010 
  6011 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  6012   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  6013 
  6014 * HOL/record: extensible records with schematic structural subtyping
  6015 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  6016 still lacks various theorems and concrete record syntax;
  6017 
  6018 
  6019 *** HOLCF ***
  6020 
  6021 * removed "axioms" and "generated by" sections;
  6022 
  6023 * replaced "ops" section by extended "consts" section, which is capable of
  6024   handling the continuous function space "->" directly;
  6025 
  6026 * domain package:
  6027   . proves theorems immediately and stores them in the theory,
  6028   . creates hierachical name space,
  6029   . now uses normal mixfix annotations (instead of cinfix...),
  6030   . minor changes to some names and values (for consistency),
  6031   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  6032   . separator between mutual domain defs: changed "," to "and",
  6033   . improved handling of sort constraints;  now they have to
  6034     appear on the left-hand side of the equations only;
  6035 
  6036 * fixed LAM <x,y,zs>.b syntax;
  6037 
  6038 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  6039 adm (%x. P (t x)), where P is chainfinite and t continuous;
  6040 
  6041 
  6042 *** FOL and ZF ***
  6043 
  6044 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6045   with `addloop' of the simplifier to faciliate case splitting in premises.
  6046 
  6047 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6048 in HOL, they strip ALL and --> from proved theorems;
  6049 
  6050 
  6051 
  6052 New in Isabelle94-8 (May 1997)
  6053 ------------------------------
  6054 
  6055 *** General Changes ***
  6056 
  6057 * new utilities to build / run / maintain Isabelle etc. (in parts
  6058 still somewhat experimental); old Makefiles etc. still functional;
  6059 
  6060 * new 'Isabelle System Manual';
  6061 
  6062 * INSTALL text, together with ./configure and ./build scripts;
  6063 
  6064 * reimplemented type inference for greater efficiency, better error
  6065 messages and clean internal interface;
  6066 
  6067 * prlim command for dealing with lots of subgoals (an easier way of
  6068 setting goals_limit);
  6069 
  6070 
  6071 *** Syntax ***
  6072 
  6073 * supports alternative (named) syntax tables (parser and pretty
  6074 printer); internal interface is provided by add_modesyntax(_i);
  6075 
  6076 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6077 be used in conjunction with the Isabelle symbol font; uses the
  6078 "symbols" syntax table;
  6079 
  6080 * added token_translation interface (may translate name tokens in
  6081 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6082 the current print_mode); IMPORTANT: user print translation functions
  6083 are responsible for marking newly introduced bounds
  6084 (Syntax.mark_boundT);
  6085 
  6086 * token translations for modes "xterm" and "xterm_color" that display
  6087 names in bold, underline etc. or colors (which requires a color
  6088 version of xterm);
  6089 
  6090 * infixes may now be declared with names independent of their syntax;
  6091 
  6092 * added typed_print_translation (like print_translation, but may
  6093 access type of constant);
  6094 
  6095 
  6096 *** Classical Reasoner ***
  6097 
  6098 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6099 some limitations.  Blast_tac...
  6100   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6101   + ignores elimination rules that don't have the correct format
  6102         (the conclusion MUST be a formula variable)
  6103   + ignores types, which can make HOL proofs fail
  6104   + rules must not require higher-order unification, e.g. apply_type in ZF
  6105     [message "Function Var's argument not a bound variable" relates to this]
  6106   + its proof strategy is more general but can actually be slower
  6107 
  6108 * substitution with equality assumptions no longer permutes other
  6109 assumptions;
  6110 
  6111 * minor changes in semantics of addafter (now called addaltern); renamed
  6112 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6113 (and access functions for it);
  6114 
  6115 * improved combination of classical reasoner and simplifier:
  6116   + functions for handling clasimpsets
  6117   + improvement of addss: now the simplifier is called _after_ the
  6118     safe steps.
  6119   + safe variant of addss called addSss: uses safe simplifications
  6120     _during_ the safe steps. It is more complete as it allows multiple
  6121     instantiations of unknowns (e.g. with slow_tac).
  6122 
  6123 *** Simplifier ***
  6124 
  6125 * added interface for simplification procedures (functions that
  6126 produce *proven* rewrite rules on the fly, depending on current
  6127 redex);
  6128 
  6129 * ordering on terms as parameter (used for ordered rewriting);
  6130 
  6131 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6132 
  6133 * the solver is now split into a safe and an unsafe part.
  6134 This should be invisible for the normal user, except that the
  6135 functions setsolver and addsolver have been renamed to setSolver and
  6136 addSolver; added safe_asm_full_simp_tac;
  6137 
  6138 
  6139 *** HOL ***
  6140 
  6141 * a generic induction tactic `induct_tac' which works for all datatypes and
  6142 also for type `nat';
  6143 
  6144 * a generic case distinction tactic `exhaust_tac' which works for all
  6145 datatypes and also for type `nat';
  6146 
  6147 * each datatype comes with a function `size';
  6148 
  6149 * patterns in case expressions allow tuple patterns as arguments to
  6150 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6151 
  6152 * primrec now also works with type nat;
  6153 
  6154 * recdef: a new declaration form, allows general recursive functions to be
  6155 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6156 
  6157 * the constant for negation has been renamed from "not" to "Not" to
  6158 harmonize with FOL, ZF, LK, etc.;
  6159 
  6160 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6161 infinite lists;
  6162 
  6163 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6164 
  6165 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6166 problems in commutative rings, using axiomatic type classes for + and *;
  6167 
  6168 * more examples in HOL/MiniML and HOL/Auth;
  6169 
  6170 * more default rewrite rules for quantifiers, union/intersection;
  6171 
  6172 * a new constant `arbitrary == @x.False';
  6173 
  6174 * HOLCF/IOA replaces old HOL/IOA;
  6175 
  6176 * HOLCF changes: derived all rules and arities
  6177   + axiomatic type classes instead of classes
  6178   + typedef instead of faking type definitions
  6179   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6180   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6181   + eliminated the types void, one, tr
  6182   + use unit lift and bool lift (with translations) instead of one and tr
  6183   + eliminated blift from Lift3.thy (use Def instead of blift)
  6184   all eliminated rules are derived as theorems --> no visible changes ;
  6185 
  6186 
  6187 *** ZF ***
  6188 
  6189 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6190 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6191 as ZF_cs addSIs [equalityI];
  6192 
  6193 
  6194 
  6195 New in Isabelle94-7 (November 96)
  6196 ---------------------------------
  6197 
  6198 * allowing negative levels (as offsets) in prlev and choplev;
  6199 
  6200 * super-linear speedup for large simplifications;
  6201 
  6202 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6203 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6204 FAIL); can suppress it using the command Delsimps (ex_simps @
  6205 all_simps); De Morgan laws are also now included, by default;
  6206 
  6207 * improved printing of ==>  :  ~:
  6208 
  6209 * new object-logic "Sequents" adds linear logic, while replacing LK
  6210 and Modal (thanks to Sara Kalvala);
  6211 
  6212 * HOL/Auth: correctness proofs for authentication protocols;
  6213 
  6214 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6215 examples on HOL/Auth);
  6216 
  6217 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6218 the rewriter and classical reasoner simultaneously;
  6219 
  6220 * function uresult no longer returns theorems in "standard" format;
  6221 regain previous version by: val uresult = standard o uresult;
  6222 
  6223 
  6224 
  6225 New in Isabelle94-6
  6226 -------------------
  6227 
  6228 * oracles -- these establish an interface between Isabelle and trusted
  6229 external reasoners, which may deliver results as theorems;
  6230 
  6231 * proof objects (in particular record all uses of oracles);
  6232 
  6233 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6234 
  6235 * "constdefs" section in theory files;
  6236 
  6237 * "primrec" section (HOL) no longer requires names;
  6238 
  6239 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6240 
  6241 
  6242 
  6243 New in Isabelle94-5
  6244 -------------------
  6245 
  6246 * reduced space requirements;
  6247 
  6248 * automatic HTML generation from theories;
  6249 
  6250 * theory files no longer require "..." (quotes) around most types;
  6251 
  6252 * new examples, including two proofs of the Church-Rosser theorem;
  6253 
  6254 * non-curried (1994) version of HOL is no longer distributed;
  6255 
  6256 
  6257 
  6258 New in Isabelle94-4
  6259 -------------------
  6260 
  6261 * greatly reduced space requirements;
  6262 
  6263 * theory files (.thy) no longer require \.