NEWS
author haftmann
Fri Jun 19 21:08:07 2009 +0200 (2009-06-19)
changeset 31726 ffd2dc631d88
parent 31720 d1ac3f3b2f54
parent 31723 f5cafe803b55
child 31784 bd3486c57ba3
permissions -rw-r--r--
merged
     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 * NewNumberTheory: Jeremy Avigad's new version of part of NumberTheory.
    57 If possible, use NewNumberTheory, not NumberTheory.
    58 
    59 *** ML ***
    60 
    61 * Eliminated old Attrib.add_attributes, Method.add_methods and related
    62 cominators for "args".  INCOMPATIBILITY, need to use simplified
    63 Attrib/Method.setup introduced in Isabelle2009.
    64 
    65 
    66 *** System ***
    67 
    68 * Discontinued support for Poly/ML 4.x versions.
    69 
    70 * Removed "compress" option from isabelle-process and isabelle usedir;
    71 this is always enabled.
    72 
    73 
    74 
    75 New in Isabelle2009 (April 2009)
    76 --------------------------------
    77 
    78 *** General ***
    79 
    80 * Simplified main Isabelle executables, with less surprises on
    81 case-insensitive file-systems (such as Mac OS).
    82 
    83   - The main Isabelle tool wrapper is now called "isabelle" instead of
    84     "isatool."
    85 
    86   - The former "isabelle" alias for "isabelle-process" has been
    87     removed (should rarely occur to regular users).
    88 
    89   - The former "isabelle-interface" and its alias "Isabelle" have been
    90     removed (interfaces are now regular Isabelle tools).
    91 
    92 Within scripts and make files, the Isabelle environment variables
    93 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    94 respectively.  (The latter are still available as legacy feature.)
    95 
    96 The old isabelle-interface wrapper could react in confusing ways if
    97 the interface was uninstalled or changed otherwise.  Individual
    98 interface tool configuration is now more explicit, see also the
    99 Isabelle system manual.  In particular, Proof General is now available
   100 via "isabelle emacs".
   101 
   102 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
   103 purge installed copies of Isabelle executables and re-run "isabelle
   104 install -p ...", or use symlinks.
   105 
   106 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
   107 old ~/isabelle, which was slightly non-standard and apt to cause
   108 surprises on case-insensitive file-systems (such as Mac OS).
   109 
   110 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
   111 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
   112 care is required when using older releases of Isabelle.  Note that
   113 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
   114 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
   115 
   116 * Proofs of fully specified statements are run in parallel on
   117 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
   118 a regular 4-core machine, if the initial heap space is made reasonably
   119 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
   120 
   121 * The main reference manuals ("isar-ref", "implementation", and
   122 "system") have been updated and extended.  Formally checked references
   123 as hyperlinks are now available uniformly.
   124 
   125 
   126 *** Pure ***
   127 
   128 * Complete re-implementation of locales.  INCOMPATIBILITY in several
   129 respects.  The most important changes are listed below.  See the
   130 Tutorial on Locales ("locales" manual) for details.
   131 
   132 - In locale expressions, instantiation replaces renaming.  Parameters
   133 must be declared in a for clause.  To aid compatibility with previous
   134 parameter inheritance, in locale declarations, parameters that are not
   135 'touched' (instantiation position "_" or omitted) are implicitly added
   136 with their syntax at the beginning of the for clause.
   137 
   138 - Syntax from abbreviations and definitions in locales is available in
   139 locale expressions and context elements.  The latter is particularly
   140 useful in locale declarations.
   141 
   142 - More flexible mechanisms to qualify names generated by locale
   143 expressions.  Qualifiers (prefixes) may be specified in locale
   144 expressions, and can be marked as mandatory (syntax: "name!:") or
   145 optional (syntax "name?:").  The default depends for plain "name:"
   146 depends on the situation where a locale expression is used: in
   147 commands 'locale' and 'sublocale' prefixes are optional, in
   148 'interpretation' and 'interpret' prefixes are mandatory.  The old
   149 implicit qualifiers derived from the parameter names of a locale are
   150 no longer generated.
   151 
   152 - Command "sublocale l < e" replaces "interpretation l < e".  The
   153 instantiation clause in "interpretation" and "interpret" (square
   154 brackets) is no longer available.  Use locale expressions.
   155 
   156 - When converting proof scripts, mandatory qualifiers in
   157 'interpretation' and 'interpret' should be retained by default, even
   158 if this is an INCOMPATIBILITY compared to former behavior.  In the
   159 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   160 in locale expressions range over a single locale instance only.
   161 
   162 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   163 In existing theorem specifications replace the includes element by the
   164 respective context elements of the included locale, omitting those
   165 that are already present in the theorem specification.  Multiple
   166 assume elements of a locale should be replaced by a single one
   167 involving the locale predicate.  In the proof body, declarations (most
   168 notably theorems) may be regained by interpreting the respective
   169 locales in the proof context as required (command "interpret").
   170 
   171 If using "includes" in replacement of a target solely because the
   172 parameter types in the theorem are not as general as in the target,
   173 consider declaring a new locale with additional type constraints on
   174 the parameters (context element "constrains").
   175 
   176 - Discontinued "locale (open)".  INCOMPATIBILITY.
   177 
   178 - Locale interpretation commands no longer attempt to simplify goal.
   179 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   180 methods intro_locales and unfold_locales to clarify.
   181 
   182 - Locale interpretation commands no longer accept interpretation
   183 attributes.  INCOMPATIBILITY.
   184 
   185 * Class declaration: so-called "base sort" must not be given in import
   186 list any longer, but is inferred from the specification.  Particularly
   187 in HOL, write
   188 
   189     class foo = ...
   190 
   191 instead of
   192 
   193     class foo = type + ...
   194 
   195 * Class target: global versions of theorems stemming do not carry a
   196 parameter prefix any longer.  INCOMPATIBILITY.
   197 
   198 * Class 'instance' command no longer accepts attached definitions.
   199 INCOMPATIBILITY, use proper 'instantiation' target instead.
   200 
   201 * Recovered hiding of consts, which was accidentally broken in
   202 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   203 makes c inaccessible; consider using ``hide (open) const c'' instead.
   204 
   205 * Slightly more coherent Pure syntax, with updated documentation in
   206 isar-ref manual.  Removed locales meta_term_syntax and
   207 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   208 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   209 directly in regular applications.
   210 
   211 * There is a new syntactic category "float_const" for signed decimal
   212 fractions (e.g. 123.45 or -123.45).
   213 
   214 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   215 interface with 'setup' command instead.
   216 
   217 * Command 'local_setup' is similar to 'setup', but operates on a local
   218 theory context.
   219 
   220 * The 'axiomatization' command now only works within a global theory
   221 context.  INCOMPATIBILITY.
   222 
   223 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   224 hypotheses.  Sorts required in the course of reasoning need to be
   225 covered by the constraints in the initial statement, completed by the
   226 type instance information of the background theory.  Non-trivial sort
   227 hypotheses, which rarely occur in practice, may be specified via
   228 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   229 
   230   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   231 
   232 The result contains an implicit sort hypotheses as before --
   233 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   234 normalization.
   235 
   236 * Generalized Isar history, with support for linear undo, direct state
   237 addressing etc.
   238 
   239 * Changed defaults for unify configuration options:
   240 
   241   unify_trace_bound = 50 (formerly 25)
   242   unify_search_bound = 60 (formerly 30)
   243 
   244 * Different bookkeeping for code equations (INCOMPATIBILITY):
   245 
   246   a) On theory merge, the last set of code equations for a particular
   247      constant is taken (in accordance with the policy applied by other
   248      parts of the code generator framework).
   249 
   250   b) Code equations stemming from explicit declarations (e.g. code
   251      attribute) gain priority over default code equations stemming
   252      from definition, primrec, fun etc.
   253 
   254 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   255 
   256 * Unified theorem tables for both code generators.  Thus [code
   257 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   258 
   259 * Command 'find_consts' searches for constants based on type and name
   260 patterns, e.g.
   261 
   262     find_consts "_ => bool"
   263 
   264 By default, matching is against subtypes, but it may be restricted to
   265 the whole type.  Searching by name is possible.  Multiple queries are
   266 conjunctive and queries may be negated by prefixing them with a
   267 hyphen:
   268 
   269     find_consts strict: "_ => bool" name: "Int" -"int => int"
   270 
   271 * New 'find_theorems' criterion "solves" matches theorems that
   272 directly solve the current goal (modulo higher-order unification).
   273 
   274 * Auto solve feature for main theorem statements: whenever a new goal
   275 is stated, "find_theorems solves" is called; any theorems that could
   276 solve the lemma directly are listed as part of the goal state.
   277 Cf. associated options in Proof General Isabelle settings menu,
   278 enabled by default, with reasonable timeout for pathological cases of
   279 higher-order unification.
   280 
   281 
   282 *** Document preparation ***
   283 
   284 * Antiquotation @{lemma} now imitates a regular terminal proof,
   285 demanding keyword 'by' and supporting the full method expression
   286 syntax just like the Isar command 'by'.
   287 
   288 
   289 *** HOL ***
   290 
   291 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   292 points Main and Complex_Main remain as before.
   293 
   294 * Logic image HOL-Plain provides a minimal HOL with the most important
   295 tools available (inductive, datatype, primrec, ...).  This facilitates
   296 experimentation and tool development.  Note that user applications
   297 (and library theories) should never refer to anything below theory
   298 Main, as before.
   299 
   300 * Logic image HOL-Main stops at theory Main, and thus facilitates
   301 experimentation due to shorter build times.
   302 
   303 * Logic image HOL-NSA contains theories of nonstandard analysis which
   304 were previously part of former HOL-Complex.  Entry point Hyperreal
   305 remains valid, but theories formerly using Complex_Main should now use
   306 new entry point Hypercomplex.
   307 
   308 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   309 Posix processes.  Avoids potentially expensive forking of the ML
   310 process.  New thread-based implementation also works on non-Unix
   311 platforms (Cygwin).  Provers are no longer hardwired, but defined
   312 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   313 commands are covered in the isar-ref manual.
   314 
   315 * Wrapper scripts for remote SystemOnTPTP service allows to use
   316 sledgehammer without local ATP installation (Vampire etc.). Other
   317 provers may be included via suitable ML wrappers, see also
   318 src/HOL/ATP_Linkup.thy.
   319 
   320 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   321 menu.
   322 
   323 * The metis method no longer fails because the theorem is too trivial
   324 (contains the empty clause).
   325 
   326 * The metis method now fails in the usual manner, rather than raising
   327 an exception, if it determines that it cannot prove the theorem.
   328 
   329 * Method "coherent" implements a prover for coherent logic (see also
   330 src/Tools/coherent.ML).
   331 
   332 * Constants "undefined" and "default" replace "arbitrary".  Usually
   333 "undefined" is the right choice to replace "arbitrary", though
   334 logically there is no difference.  INCOMPATIBILITY.
   335 
   336 * Command "value" now integrates different evaluation mechanisms.  The
   337 result of the first successful evaluation mechanism is printed.  In
   338 square brackets a particular named evaluation mechanisms may be
   339 specified (currently, [SML], [code] or [nbe]).  See further
   340 src/HOL/ex/Eval_Examples.thy.
   341 
   342 * Normalization by evaluation now allows non-leftlinear equations.
   343 Declare with attribute [code nbe].
   344 
   345 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   346 as the structured Isar versions "cases" and "induct", cf. the
   347 corresponding "cases" and "induct" attributes.  Mutual induction rules
   348 are now presented as a list of individual projections
   349 (e.g. foo_bar.inducts for types foo and bar); the old format with
   350 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   351 rare situations a different rule is selected --- notably nested tuple
   352 elimination instead of former prod.exhaust: use explicit (case_tac t
   353 rule: prod.exhaust) here.
   354 
   355 * Attributes "cases", "induct", "coinduct" support "del" option.
   356 
   357 * Removed fact "case_split_thm", which duplicates "case_split".
   358 
   359 * The option datatype has been moved to a new theory Option.  Renamed
   360 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   361 
   362 * New predicate "strict_mono" classifies strict functions on partial
   363 orders.  With strict functions on linear orders, reasoning about
   364 (in)equalities is facilitated by theorems "strict_mono_eq",
   365 "strict_mono_less_eq" and "strict_mono_less".
   366 
   367 * Some set operations are now proper qualified constants with
   368 authentic syntax.  INCOMPATIBILITY:
   369 
   370     op Int ~>   Set.Int
   371     op Un ~>    Set.Un
   372     INTER ~>    Set.INTER
   373     UNION ~>    Set.UNION
   374     Inter ~>    Set.Inter
   375     Union ~>    Set.Union
   376     {} ~>       Set.empty
   377     UNIV ~>     Set.UNIV
   378 
   379 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   380 theory Set.
   381 
   382 * Auxiliary class "itself" has disappeared -- classes without any
   383 parameter are treated as expected by the 'class' command.
   384 
   385 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   386 
   387 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   388 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   389 
   390 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   391 method "approximation".  It proves formulas on real values by using
   392 interval arithmetic.  In the formulas are also the transcendental
   393 functions sin, cos, tan, atan, ln, exp and the constant pi are
   394 allowed. For examples see
   395 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   396 
   397 * Theory "Reflection" now resides in HOL/Library.
   398 
   399 * Entry point to Word library now simply named "Word".
   400 INCOMPATIBILITY.
   401 
   402 * Made source layout more coherent with logical distribution
   403 structure:
   404 
   405     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   406     src/HOL/Library/Code_Message.thy ~> src/HOL/
   407     src/HOL/Library/GCD.thy ~> src/HOL/
   408     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   409     src/HOL/Library/Parity.thy ~> src/HOL/
   410     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   411     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   412     src/HOL/Real/Lubs.thy ~> src/HOL/
   413     src/HOL/Real/PReal.thy ~> src/HOL/
   414     src/HOL/Real/Rational.thy ~> src/HOL/
   415     src/HOL/Real/RComplete.thy ~> src/HOL/
   416     src/HOL/Real/RealDef.thy ~> src/HOL/
   417     src/HOL/Real/RealPow.thy ~> src/HOL/
   418     src/HOL/Real/Real.thy ~> src/HOL/
   419     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   420     src/HOL/Complex/Complex.thy ~> src/HOL/
   421     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   422     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   423     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   424     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   425     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   426     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   427     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   428     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   429     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   430     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   431     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   432     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   433     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   434     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   435     src/HOL/Real/Float ~> src/HOL/Library/
   436     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   437     src/HOL/Real/RealVector.thy ~> src/HOL/
   438 
   439     src/HOL/arith_data.ML ~> src/HOL/Tools
   440     src/HOL/hologic.ML ~> src/HOL/Tools
   441     src/HOL/simpdata.ML ~> src/HOL/Tools
   442     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   443     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   444     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   445     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   446     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   447     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   448     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   449 
   450     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   451     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   452     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   453     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   454     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   455     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   456 
   457 * If methods "eval" and "evaluation" encounter a structured proof
   458 state with !!/==>, only the conclusion is evaluated to True (if
   459 possible), avoiding strange error messages.
   460 
   461 * Method "sizechange" automates termination proofs using (a
   462 modification of) the size-change principle.  Requires SAT solver.  See
   463 src/HOL/ex/Termination.thy for examples.
   464 
   465 * Simplifier: simproc for let expressions now unfolds if bound
   466 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   467 
   468 * Method "arith": Linear arithmetic now ignores all inequalities when
   469 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   470 
   471 * New attribute "arith" for facts that should always be used
   472 automatically by arithmetic. It is intended to be used locally in
   473 proofs, e.g.
   474 
   475   assumes [arith]: "x > 0"
   476 
   477 Global usage is discouraged because of possible performance impact.
   478 
   479 * New classes "top" and "bot" with corresponding operations "top" and
   480 "bot" in theory Orderings; instantiation of class "complete_lattice"
   481 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   482 
   483 * Changed definition lemma "less_fun_def" in order to provide an
   484 instance for preorders on functions; use lemma "less_le" instead.
   485 INCOMPATIBILITY.
   486 
   487 * Theory Orderings: class "wellorder" moved here, with explicit
   488 induction rule "less_induct" as assumption.  For instantiation of
   489 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   490 INCOMPATIBILITY.
   491 
   492 * Theory Orderings: added class "preorder" as superclass of "order".
   493 INCOMPATIBILITY: Instantiation proofs for order, linorder
   494 etc. slightly changed.  Some theorems named order_class.* now named
   495 preorder_class.*.
   496 
   497 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   498 "diag" to "Id_on".
   499 
   500 * Theory Finite_Set: added a new fold combinator of type
   501 
   502   ('a => 'b => 'b) => 'b => 'a set => 'b
   503 
   504 Occasionally this is more convenient than the old fold combinator
   505 which is now defined in terms of the new one and renamed to
   506 fold_image.
   507 
   508 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   509 and "ring_simps" have been replaced by "algebra_simps" (which can be
   510 extended with further lemmas!).  At the moment both still exist but
   511 the former will disappear at some point.
   512 
   513 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   514 class recpower.  Type-specific simp rules for various recpower types
   515 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   516 
   517 rat_power_0    -> power_0
   518 rat_power_Suc  -> power_Suc
   519 realpow_0      -> power_0
   520 realpow_Suc    -> power_Suc
   521 complexpow_0   -> power_0
   522 complexpow_Suc -> power_Suc
   523 power_poly_0   -> power_0
   524 power_poly_Suc -> power_Suc
   525 
   526 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   527 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   528 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   529 of lemmas from Divides has been generalized from nat to class
   530 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   531 renames resulting from duplicate elimination:
   532 
   533     dvd_def_mod ~>          dvd_eq_mod_eq_0
   534     zero_dvd_iff ~>         dvd_0_left_iff
   535     dvd_0 ~>                dvd_0_right
   536     DIVISION_BY_ZERO_DIV ~> div_by_0
   537     DIVISION_BY_ZERO_MOD ~> mod_by_0
   538     mult_div ~>             div_mult_self2_is_id
   539     mult_mod ~>             mod_mult_self2_is_0
   540 
   541 * Theory IntDiv: removed many lemmas that are instances of class-based
   542 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   543 rename old lemmas as follows:
   544 
   545 dvd_diff               -> nat_dvd_diff
   546 dvd_zminus_iff         -> dvd_minus_iff
   547 mod_add1_eq            -> mod_add_eq
   548 mod_mult1_eq           -> mod_mult_right_eq
   549 mod_mult1_eq'          -> mod_mult_left_eq
   550 mod_mult_distrib_mod   -> mod_mult_eq
   551 nat_mod_add_left_eq    -> mod_add_left_eq
   552 nat_mod_add_right_eq   -> mod_add_right_eq
   553 nat_mod_div_trivial    -> mod_div_trivial
   554 nat_mod_mod_trivial    -> mod_mod_trivial
   555 zdiv_zadd_self1        -> div_add_self1
   556 zdiv_zadd_self2        -> div_add_self2
   557 zdiv_zmult_self1       -> div_mult_self2_is_id
   558 zdiv_zmult_self2       -> div_mult_self1_is_id
   559 zdvd_triv_left         -> dvd_triv_left
   560 zdvd_triv_right        -> dvd_triv_right
   561 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   562 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   563 zmod_zadd_left_eq      -> mod_add_left_eq
   564 zmod_zadd_right_eq     -> mod_add_right_eq
   565 zmod_zadd_self1        -> mod_add_self1
   566 zmod_zadd_self2        -> mod_add_self2
   567 zmod_zadd1_eq          -> mod_add_eq
   568 zmod_zdiff1_eq         -> mod_diff_eq
   569 zmod_zdvd_zmod         -> mod_mod_cancel
   570 zmod_zmod_cancel       -> mod_mod_cancel
   571 zmod_zmult_self1       -> mod_mult_self2_is_0
   572 zmod_zmult_self2       -> mod_mult_self1_is_0
   573 zmod_1                 -> mod_by_1
   574 zdiv_1                 -> div_by_1
   575 zdvd_abs1              -> abs_dvd_iff
   576 zdvd_abs2              -> dvd_abs_iff
   577 zdvd_refl              -> dvd_refl
   578 zdvd_trans             -> dvd_trans
   579 zdvd_zadd              -> dvd_add
   580 zdvd_zdiff             -> dvd_diff
   581 zdvd_zminus_iff        -> dvd_minus_iff
   582 zdvd_zminus2_iff       -> minus_dvd_iff
   583 zdvd_zmultD            -> dvd_mult_right
   584 zdvd_zmultD2           -> dvd_mult_left
   585 zdvd_zmult_mono        -> mult_dvd_mono
   586 zdvd_0_right           -> dvd_0_right
   587 zdvd_0_left            -> dvd_0_left_iff
   588 zdvd_1_left            -> one_dvd
   589 zminus_dvd_iff         -> minus_dvd_iff
   590 
   591 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   592 
   593 * The real numbers offer decimal input syntax: 12.34 is translated
   594 into 1234/10^2. This translation is not reversed upon output.
   595 
   596 * Theory Library/Polynomial defines an abstract type 'a poly of
   597 univariate polynomials with coefficients of type 'a.  In addition to
   598 the standard ring operations, it also supports div and mod.  Code
   599 generation is also supported, using list-style constructors.
   600 
   601 * Theory Library/Inner_Product defines a class of real_inner for real
   602 inner product spaces, with an overloaded operation inner :: 'a => 'a
   603 => real.  Class real_inner is a subclass of real_normed_vector from
   604 theory RealVector.
   605 
   606 * Theory Library/Product_Vector provides instances for the product
   607 type 'a * 'b of several classes from RealVector and Inner_Product.
   608 Definitions of addition, subtraction, scalar multiplication, norms,
   609 and inner products are included.
   610 
   611 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   612 addition to the field operations, numerals and case syntax are also
   613 supported.
   614 
   615 * Theory Library/Diagonalize provides constructive version of Cantor's
   616 first diagonalization argument.
   617 
   618 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   619 zlcm (for int); carried together from various gcd/lcm developements in
   620 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   621 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   622 may recover tupled syntax as follows:
   623 
   624     hide (open) const gcd
   625     abbreviation gcd where
   626       "gcd == (%(a, b). GCD.gcd a b)"
   627     notation (output)
   628       GCD.gcd ("gcd '(_, _')")
   629 
   630 The same works for lcm, zgcd, zlcm.
   631 
   632 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   633 instantiations for algebraic structures.  Removed some duplicate
   634 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   635 
   636 * ML antiquotation @{code} takes a constant as argument and generates
   637 corresponding code in background and inserts name of the corresponding
   638 resulting ML value/function/datatype constructor binding in place.
   639 All occurrences of @{code} with a single ML block are generated
   640 simultaneously.  Provides a generic and safe interface for
   641 instrumentalizing code generation.  See
   642 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   643 In future you ought to refrain from ad-hoc compiling generated SML
   644 code on the ML toplevel.  Note that (for technical reasons) @{code}
   645 cannot refer to constants for which user-defined serializations are
   646 set.  Refer to the corresponding ML counterpart directly in that
   647 cases.
   648 
   649 * Command 'rep_datatype': instead of theorem names the command now
   650 takes a list of terms denoting the constructors of the type to be
   651 represented as datatype.  The characteristic theorems have to be
   652 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   653 have disappeared in favour of existing ones:
   654 
   655     unit_induct                 ~> unit.induct
   656     prod_induct                 ~> prod.induct
   657     sum_induct                  ~> sum.induct
   658     Suc_Suc_eq                  ~> nat.inject
   659     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   660 
   661 
   662 *** HOL-Algebra ***
   663 
   664 * New locales for orders and lattices where the equivalence relation
   665 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   666 locales use a record structure with field eq for the equivalence.
   667 
   668 * New theory of factorial domains.
   669 
   670 * Units_l_inv and Units_r_inv are now simp rules by default.
   671 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   672 and/or r_inv will now also require deletion of these lemmas.
   673 
   674 * Renamed the following theorems, INCOMPATIBILITY:
   675 
   676 UpperD ~> Upper_memD
   677 LowerD ~> Lower_memD
   678 least_carrier ~> least_closed
   679 greatest_carrier ~> greatest_closed
   680 greatest_Lower_above ~> greatest_Lower_below
   681 one_zero ~> carrier_one_zero
   682 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   683 
   684 
   685 *** HOL-Nominal ***
   686 
   687 * Nominal datatypes can now contain type-variables.
   688 
   689 * Commands 'nominal_inductive' and 'equivariance' work with local
   690 theory targets.
   691 
   692 * Nominal primrec can now works with local theory targets and its
   693 specification syntax now conforms to the general format as seen in
   694 'inductive' etc.
   695 
   696 * Method "perm_simp" honours the standard simplifier attributes
   697 (no_asm), (no_asm_use) etc.
   698 
   699 * The new predicate #* is defined like freshness, except that on the
   700 left hand side can be a set or list of atoms.
   701 
   702 * Experimental command 'nominal_inductive2' derives strong induction
   703 principles for inductive definitions.  In contrast to
   704 'nominal_inductive', which can only deal with a fixed number of
   705 binders, it can deal with arbitrary expressions standing for sets of
   706 atoms to be avoided.  The only inductive definition we have at the
   707 moment that needs this generalisation is the typing rule for Lets in
   708 the algorithm W:
   709 
   710  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   711  -----------------------------------------------------------------
   712          Gamma |- Let x be t1 in t2 : T2
   713 
   714 In this rule one wants to avoid all the binders that are introduced by
   715 "close Gamma T1".  We are looking for other examples where this
   716 feature might be useful.  Please let us know.
   717 
   718 
   719 *** HOLCF ***
   720 
   721 * Reimplemented the simplification procedure for proving continuity
   722 subgoals.  The new simproc is extensible; users can declare additional
   723 continuity introduction rules with the attribute [cont2cont].
   724 
   725 * The continuity simproc now uses a different introduction rule for
   726 solving continuity subgoals on terms with lambda abstractions.  In
   727 some rare cases the new simproc may fail to solve subgoals that the
   728 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   729 Potential INCOMPATIBILITY.
   730 
   731 * Command 'fixrec': specification syntax now conforms to the general
   732 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   733 examples.  INCOMPATIBILITY.
   734 
   735 
   736 *** ZF ***
   737 
   738 * Proof of Zorn's Lemma for partial orders.
   739 
   740 
   741 *** ML ***
   742 
   743 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   744 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   745 depends on multithreading, so timouts will not work before Poly/ML
   746 5.2.1!
   747 
   748 * High-level support for concurrent ML programming, see
   749 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   750 particularly convenient to organize independent functional
   751 computations.  The concept of "synchronized variables" provides a
   752 higher-order interface for components with shared state, avoiding the
   753 delicate details of mutexes and condition variables.  (Requires
   754 Poly/ML 5.2.1 or later.)
   755 
   756 * ML bindings produced via Isar commands are stored within the Isar
   757 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   758 become thread-safe and work with undo as expected (concerning
   759 top-level bindings, not side-effects on global references).
   760 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   761 compiler at runtime; really global bindings need to be given outside a
   762 theory.  (Requires Poly/ML 5.2 or later.)
   763 
   764 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   765 context.  Top-level ML bindings are stored within the proof context in
   766 a purely sequential fashion, disregarding the nested proof structure.
   767 ML bindings introduced by 'ML_prf' are discarded at the end of the
   768 proof.  (Requires Poly/ML 5.2 or later.)
   769 
   770 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   771 and Method.setup, as well as Isar commands 'attribute_setup' and
   772 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   773 existing code accordingly, or use plain 'setup' together with old
   774 Method.add_method.
   775 
   776 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   777 to 'a -> thm, while results are always tagged with an authentic oracle
   778 name.  The Isar command 'oracle' is now polymorphic, no argument type
   779 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   780 accordingly.  Note that extra performance may be gained by producing
   781 the cterm carefully, avoiding slow Thm.cterm_of.
   782 
   783 * Simplified interface for defining document antiquotations via
   784 ThyOutput.antiquotation, ThyOutput.output, and optionally
   785 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   786 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   787 examples.
   788 
   789 * More systematic treatment of long names, abstract name bindings, and
   790 name space operations.  Basic operations on qualified names have been
   791 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   792 Long_Name.append.  Old type bstring has been mostly replaced by
   793 abstract type binding (see structure Binding), which supports precise
   794 qualification by packages and local theory targets, as well as proper
   795 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   796 bstring values into Binding.name, or better pass through abstract
   797 bindings everywhere.  See further src/Pure/General/long_name.ML,
   798 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   799 
   800 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   801 LocalTheory.note etc.) now refer to the *full* internal name, not the
   802 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   803 
   804 * Disposed old type and term read functions (Sign.read_def_typ,
   805 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   806 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   807 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   808 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   809 resort for legacy applications.
   810 
   811 * Disposed old declarations, tactics, tactic combinators that refer to
   812 the simpset or claset of an implicit theory (such as Addsimps,
   813 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   814 embedded ML text, or local_simpset_of with a proper context passed as
   815 explicit runtime argument.
   816 
   817 * Rules and tactics that read instantiations (read_instantiate,
   818 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   819 context, which is required for parsing and type-checking.  Moreover,
   820 the variables are specified as plain indexnames, not string encodings
   821 thereof.  INCOMPATIBILITY.
   822 
   823 * Generic Toplevel.add_hook interface allows to analyze the result of
   824 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   825 for theorem dependency output of transactions resulting in a new
   826 theory state.
   827 
   828 * ML antiquotations: block-structured compilation context indicated by
   829 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   830 
   831   @{binding name}                         - basic name binding
   832   @{let ?pat = term}                      - term abbreviation (HO matching)
   833   @{note name = fact}                     - fact abbreviation
   834   @{thm fact}                             - singleton fact (with attributes)
   835   @{thms fact}                            - general fact (with attributes)
   836   @{lemma prop by method}                 - singleton goal
   837   @{lemma prop by meth1 meth2}            - singleton goal
   838   @{lemma prop1 ... propN by method}      - general goal
   839   @{lemma prop1 ... propN by meth1 meth2} - general goal
   840   @{lemma (open) ...}                     - open derivation
   841 
   842 
   843 *** System ***
   844 
   845 * The Isabelle "emacs" tool provides a specific interface to invoke
   846 Proof General / Emacs, with more explicit failure if that is not
   847 installed (the old isabelle-interface script silently falls back on
   848 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   849 installation location of the Proof General distribution.
   850 
   851 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   852 the Isabelle process into a JVM/Scala application.  See
   853 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   854 process wrapper has been discontinued.)
   855 
   856 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   857 
   858 * Various status messages (with exact source position information) are
   859 emitted, if proper markup print mode is enabled.  This allows
   860 user-interface components to provide detailed feedback on internal
   861 prover operations.
   862 
   863 
   864 
   865 New in Isabelle2008 (June 2008)
   866 -------------------------------
   867 
   868 *** General ***
   869 
   870 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   871 and updated, with formally checked references as hyperlinks.
   872 
   873 * Theory loader: use_thy (and similar operations) no longer set the
   874 implicit ML context, which was occasionally hard to predict and in
   875 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   876 provides a proper context already.
   877 
   878 * Theory loader: old-style ML proof scripts being *attached* to a thy
   879 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   880 'use' within a theory file will do the job.
   881 
   882 * Name space merge now observes canonical order, i.e. the second space
   883 is inserted into the first one, while existing entries in the first
   884 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   885 swap theory imports.
   886 
   887 * Syntax: symbol \<chi> is now considered a letter.  Potential
   888 INCOMPATIBILITY in identifier syntax etc.
   889 
   890 * Outer syntax: string tokens no longer admit escaped white space,
   891 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   892 white space without escapes.
   893 
   894 * Outer syntax: string tokens may contain arbitrary character codes
   895 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   896 "foo_bar".
   897 
   898 
   899 *** Pure ***
   900 
   901 * Context-dependent token translations.  Default setup reverts locally
   902 fixed variables, and adds hilite markup for undeclared frees.
   903 
   904 * Unused theorems can be found using the new command 'unused_thms'.
   905 There are three ways of invoking it:
   906 
   907 (1) unused_thms
   908      Only finds unused theorems in the current theory.
   909 
   910 (2) unused_thms thy_1 ... thy_n -
   911      Finds unused theorems in the current theory and all of its ancestors,
   912      excluding the theories thy_1 ... thy_n and all of their ancestors.
   913 
   914 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   915      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   916      their ancestors, excluding the theories thy_1 ... thy_n and all of
   917      their ancestors.
   918 
   919 In order to increase the readability of the list produced by
   920 unused_thms, theorems that have been created by a particular instance
   921 of a theory command such as 'inductive' or 'function' are considered
   922 to belong to the same "group", meaning that if at least one theorem in
   923 this group is used, the other theorems in the same group are no longer
   924 reported as unused.  Moreover, if all theorems in the group are
   925 unused, only one theorem in the group is displayed.
   926 
   927 Note that proof objects have to be switched on in order for
   928 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   929 usually the case when using Proof General with the default settings).
   930 
   931 * Authentic naming of facts disallows ad-hoc overwriting of previous
   932 theorems within the same name space.  INCOMPATIBILITY, need to remove
   933 duplicate fact bindings, or even accidental fact duplications.  Note
   934 that tools may maintain dynamically scoped facts systematically, using
   935 PureThy.add_thms_dynamic.
   936 
   937 * Command 'hide' now allows to hide from "fact" name space as well.
   938 
   939 * Eliminated destructive theorem database, simpset, claset, and
   940 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   941 update of theories within ML code.
   942 
   943 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   944 INCOMPATIBILITY, object-logics depending on former Pure require
   945 additional setup PureThy.old_appl_syntax_setup; object-logics
   946 depending on former CPure need to refer to Pure.
   947 
   948 * Commands 'use' and 'ML' are now purely functional, operating on
   949 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   950 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   951 INCOMPATIBILITY.
   952 
   953 * Command 'setup': discontinued implicit version with ML reference.
   954 
   955 * Instantiation target allows for simultaneous specification of class
   956 instance operations together with an instantiation proof.
   957 Type-checking phase allows to refer to class operations uniformly.
   958 See src/HOL/Complex/Complex.thy for an Isar example and
   959 src/HOL/Library/Eval.thy for an ML example.
   960 
   961 * Indexing of literal facts: be more serious about including only
   962 facts from the visible specification/proof context, but not the
   963 background context (locale etc.).  Affects `prop` notation and method
   964 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   965 situations.
   966 
   967 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   968 "(open)" option, which used to expose internal bound variables to the
   969 proof text.
   970 
   971 * Isar statements: removed obsolete case "rule_context".
   972 INCOMPATIBILITY, better use explicit fixes/assumes.
   973 
   974 * Locale proofs: default proof step now includes 'unfold_locales';
   975 hence 'proof' without argument may be used to unfold locale
   976 predicates.
   977 
   978 
   979 *** Document preparation ***
   980 
   981 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   982 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   983 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   984 spot); renamed link color from "darkblue" to "linkcolor" (default
   985 value unchanged, can be redefined via \definecolor); no longer sets
   986 "a4paper" option (unnecessary or even intrusive).
   987 
   988 * Antiquotation @{lemma A method} proves proposition A by the given
   989 method (either a method name or a method name plus (optional) method
   990 arguments in parentheses) and prints A just like @{prop A}.
   991 
   992 
   993 *** HOL ***
   994 
   995 * New primrec package.  Specification syntax conforms in style to
   996 definition/function/....  No separate induction rule is provided.  The
   997 "primrec" command distinguishes old-style and new-style specifications
   998 by syntax.  The former primrec package is now named OldPrimrecPackage.
   999 When adjusting theories, beware: constants stemming from new-style
  1000 primrec specifications have authentic syntax.
  1001 
  1002 * Metis prover is now an order of magnitude faster, and also works
  1003 with multithreading.
  1004 
  1005 * Metis: the maximum number of clauses that can be produced from a
  1006 theorem is now given by the attribute max_clauses.  Theorems that
  1007 exceed this number are ignored, with a warning printed.
  1008 
  1009 * Sledgehammer no longer produces structured proofs by default. To
  1010 enable, declare [[sledgehammer_full = true]].  Attributes
  1011 reconstruction_modulus, reconstruction_sorts renamed
  1012 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
  1013 
  1014 * Method "induct_scheme" derives user-specified induction rules
  1015 from well-founded induction and completeness of patterns. This factors
  1016 out some operations that are done internally by the function package
  1017 and makes them available separately.  See
  1018 src/HOL/ex/Induction_Scheme.thy for examples.
  1019 
  1020 * More flexible generation of measure functions for termination
  1021 proofs: Measure functions can be declared by proving a rule of the
  1022 form "is_measure f" and giving it the [measure_function] attribute.
  1023 The "is_measure" predicate is logically meaningless (always true), and
  1024 just guides the heuristic.  To find suitable measure functions, the
  1025 termination prover sets up the goal "is_measure ?f" of the appropriate
  1026 type and generates all solutions by prolog-style backwards proof using
  1027 the declared rules.
  1028 
  1029 This setup also deals with rules like 
  1030 
  1031   "is_measure f ==> is_measure (list_size f)"
  1032 
  1033 which accommodates nested datatypes that recurse through lists.
  1034 Similar rules are predeclared for products and option types.
  1035 
  1036 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
  1037 
  1038   INCOMPATIBILITIES:
  1039 
  1040   - Definitions of overloaded constants on sets have to be replaced by
  1041     definitions on => and bool.
  1042 
  1043   - Some definitions of overloaded operators on sets can now be proved
  1044     using the definitions of the operators on => and bool.  Therefore,
  1045     the following theorems have been renamed:
  1046 
  1047       subset_def   -> subset_eq
  1048       psubset_def  -> psubset_eq
  1049       set_diff_def -> set_diff_eq
  1050       Compl_def    -> Compl_eq
  1051       Sup_set_def  -> Sup_set_eq
  1052       Inf_set_def  -> Inf_set_eq
  1053       sup_set_def  -> sup_set_eq
  1054       inf_set_def  -> inf_set_eq
  1055 
  1056   - Due to the incompleteness of the HO unification algorithm, some
  1057     rules such as subst may require manual instantiation, if some of
  1058     the unknowns in the rule is a set.
  1059 
  1060   - Higher order unification and forward proofs:
  1061     The proof pattern
  1062 
  1063       have "P (S::'a set)" <...>
  1064       then have "EX S. P S" ..
  1065 
  1066     no longer works (due to the incompleteness of the HO unification
  1067     algorithm) and must be replaced by the pattern
  1068 
  1069       have "EX S. P S"
  1070       proof
  1071         show "P S" <...>
  1072       qed
  1073 
  1074   - Calculational reasoning with subst (or similar rules):
  1075     The proof pattern
  1076 
  1077       have "P (S::'a set)" <...>
  1078       also have "S = T" <...>
  1079       finally have "P T" .
  1080 
  1081     no longer works (for similar reasons as the previous example) and
  1082     must be replaced by something like
  1083 
  1084       have "P (S::'a set)" <...>
  1085       moreover have "S = T" <...>
  1086       ultimately have "P T" by simp
  1087 
  1088   - Tactics or packages written in ML code:
  1089     Code performing pattern matching on types via
  1090 
  1091       Type ("set", [T]) => ...
  1092 
  1093     must be rewritten. Moreover, functions like strip_type or
  1094     binder_types no longer return the right value when applied to a
  1095     type of the form
  1096 
  1097       T1 => ... => Tn => U => bool
  1098 
  1099     rather than
  1100 
  1101       T1 => ... => Tn => U set
  1102 
  1103 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1104 Wellfounded_Relations to theory Wellfounded.
  1105 
  1106 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1107 
  1108 * Class finite no longer treats UNIV as class parameter.  Use class
  1109 enum from theory Library/Enum instead to achieve a similar effect.
  1110 INCOMPATIBILITY.
  1111 
  1112 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1113 and "Cons".  INCOMPATIBILITY.
  1114 
  1115 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1116 Potential INCOMPATIBILITY.
  1117 
  1118 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1119 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1120 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1121 
  1122 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1123 the same name in theory Orderings:
  1124 
  1125   less_trans
  1126   less_linear
  1127   le_imp_less_or_eq
  1128   le_less_trans
  1129   less_le_trans
  1130   less_not_sym
  1131   less_asym
  1132 
  1133 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1134 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1135 and different variable names.
  1136 
  1137 * Library/Option_ord.thy: Canonical order on option type.
  1138 
  1139 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1140 finite maps.
  1141 
  1142 * Library/Countable.thy: Type class for countable types.
  1143 
  1144 * Theory Int: The representation of numerals has changed.  The infix
  1145 operator BIT and the bit datatype with constructors B0 and B1 have
  1146 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1147 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1148 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1149 accordingly.
  1150 
  1151 * Theory Nat: definition of <= and < on natural numbers no longer
  1152 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1153 le_def and less_def have disappeared.  Consider lemmas not_less
  1154 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1155 
  1156 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1157 (whose purpose mainly is for various fold_set functionals) have been
  1158 abandoned in favor of the existing algebraic classes
  1159 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1160 lower_semilattice (resp. upper_semilattice) and linorder.
  1161 INCOMPATIBILITY.
  1162 
  1163 * Theory Transitive_Closure: induct and cases rules now declare proper
  1164 case_names ("base" and "step").  INCOMPATIBILITY.
  1165 
  1166 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1167 lattices.  The form set-specific version is available as
  1168 Inductive.lfp_ordinal_induct_set.
  1169 
  1170 * Renamed theorems "power.simps" to "power_int.simps".
  1171 INCOMPATIBILITY.
  1172 
  1173 * Class semiring_div provides basic abstract properties of semirings
  1174 with division and modulo operations.  Subsumes former class dvd_mod.
  1175 
  1176 * Merged theories IntDef, Numeral and IntArith into unified theory
  1177 Int.  INCOMPATIBILITY.
  1178 
  1179 * Theory Library/Code_Index: type "index" now represents natural
  1180 numbers rather than integers.  INCOMPATIBILITY.
  1181 
  1182 * New class "uminus" with operation "uminus" (split of from class
  1183 "minus" which now only has operation "minus", binary).
  1184 INCOMPATIBILITY.
  1185 
  1186 * Constants "card", "internal_split", "option_map" now with authentic
  1187 syntax.  INCOMPATIBILITY.
  1188 
  1189 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1190 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1191 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1192 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1193 Sup_set_def, le_def, less_def, option_map_def now with object
  1194 equality.  INCOMPATIBILITY.
  1195 
  1196 * Records. Removed K_record, and replaced it by pure lambda term
  1197 %x. c. The simplifier setup is now more robust against eta expansion.
  1198 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1199 
  1200 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1201 
  1202 * Library/ListVector: new theory of arithmetic vector operations.
  1203 
  1204 * Library/Order_Relation: new theory of various orderings as sets of
  1205 pairs.  Defines preorders, partial orders, linear orders and
  1206 well-orders on sets and on types.
  1207 
  1208 
  1209 *** ZF ***
  1210 
  1211 * Renamed some theories to allow to loading both ZF and HOL in the
  1212 same session:
  1213 
  1214   Datatype  -> Datatype_ZF
  1215   Inductive -> Inductive_ZF
  1216   Int       -> Int_ZF
  1217   IntDiv    -> IntDiv_ZF
  1218   Nat       -> Nat_ZF
  1219   List      -> List_ZF
  1220   Main      -> Main_ZF
  1221 
  1222 INCOMPATIBILITY: ZF theories that import individual theories below
  1223 Main might need to be adapted.  Regular theory Main is still
  1224 available, as trivial extension of Main_ZF.
  1225 
  1226 
  1227 *** ML ***
  1228 
  1229 * ML within Isar: antiquotation @{const name} or @{const
  1230 name(typargs)} produces statically-checked Const term.
  1231 
  1232 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1233 (of the same name).  Removed obsolete print command.
  1234 
  1235 * Removed obsolete "use_legacy_bindings" function.
  1236 
  1237 * The ``print mode'' is now a thread-local value derived from a global
  1238 template (the former print_mode reference), thus access becomes
  1239 non-critical.  The global print_mode reference is for session
  1240 management only; user-code should use print_mode_value,
  1241 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1242 
  1243 * Functions system/system_out provide a robust way to invoke external
  1244 shell commands, with propagation of interrupts (requires Poly/ML
  1245 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1246 
  1247 
  1248 *** System ***
  1249 
  1250 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1251 in accordance with Proof General 3.7, which prefers GNU emacs.
  1252 
  1253 * isatool tty runs Isabelle process with plain tty interaction;
  1254 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1255 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1256 
  1257 * isatool browser now works with Cygwin as well, using general
  1258 "javapath" function defined in Isabelle process environment.
  1259 
  1260 * YXML notation provides a simple and efficient alternative to
  1261 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1262 isatool yxml as described in the Isabelle system manual.
  1263 
  1264 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1265 provides general wrapper for managing an Isabelle process in a robust
  1266 fashion, with ``cooked'' output from stdin/stderr.
  1267 
  1268 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1269 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1270 
  1271 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1272 way of changing the user's settings is via
  1273 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1274 script.
  1275 
  1276 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1277 cores of the underlying machine, which is a good starting point for
  1278 optimal performance tuning.  The corresponding usedir option -M allows
  1279 "max" as an alias for "0".  WARNING: does not work on certain versions
  1280 of Mac OS (with Poly/ML 5.1).
  1281 
  1282 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1283 adverse effect of Isabelle flooding interactive front-ends (notably
  1284 ProofGeneral / XEmacs).
  1285 
  1286 
  1287 
  1288 New in Isabelle2007 (November 2007)
  1289 -----------------------------------
  1290 
  1291 *** General ***
  1292 
  1293 * More uniform information about legacy features, notably a
  1294 warning/error of "Legacy feature: ...", depending on the state of the
  1295 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1296 legacy features will disappear eventually.
  1297 
  1298 * Theory syntax: the header format ``theory A = B + C:'' has been
  1299 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1300 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1301 
  1302 * Theory syntax: the old non-Isar theory file format has been
  1303 discontinued altogether.  Note that ML proof scripts may still be used
  1304 with Isar theories; migration is usually quite simple with the ML
  1305 function use_legacy_bindings.  INCOMPATIBILITY.
  1306 
  1307 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1308 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1309 quotes.
  1310 
  1311 * Theory loader: be more serious about observing the static theory
  1312 header specifications (including optional directories), but not the
  1313 accidental file locations of previously successful loads.  The strict
  1314 update policy of former update_thy is now already performed by
  1315 use_thy, so the former has been removed; use_thys updates several
  1316 theories simultaneously, just as 'imports' within a theory header
  1317 specification, but without merging the results.  Potential
  1318 INCOMPATIBILITY: may need to refine theory headers and commands
  1319 ROOT.ML which depend on load order.
  1320 
  1321 * Theory loader: optional support for content-based file
  1322 identification, instead of the traditional scheme of full physical
  1323 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1324 (cf. the system manual).  The new scheme allows to work with
  1325 non-finished theories in persistent session images, such that source
  1326 files may be moved later on without requiring reloads.
  1327 
  1328 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1329 file (with the same base name as the theory) are considered a legacy
  1330 feature, which will disappear eventually. Even now, the theory loader
  1331 no longer maintains dependencies on such files.
  1332 
  1333 * Syntax: the scope for resolving ambiguities via type-inference is
  1334 now limited to individual terms, instead of whole simultaneous
  1335 specifications as before. This greatly reduces the complexity of the
  1336 syntax module and improves flexibility by separating parsing and
  1337 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1338 'fixes' etc.) are required in rare situations.
  1339 
  1340 * Syntax: constants introduced by new-style packages ('definition',
  1341 'abbreviation' etc.) are passed through the syntax module in
  1342 ``authentic mode''. This means that associated mixfix annotations
  1343 really stick to such constants, independently of potential name space
  1344 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1345 trees are represented slightly differently, may need to adapt syntax
  1346 translations accordingly. Use CONST marker in 'translations' and
  1347 @{const_syntax} antiquotation in 'parse_translation' etc.
  1348 
  1349 * Legacy goal package: reduced interface to the bare minimum required
  1350 to keep existing proof scripts running.  Most other user-level
  1351 functions are now part of the OldGoals structure, which is *not* open
  1352 by default (consider isatool expandshort before open OldGoals).
  1353 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1354 these tend to cause confusion about the actual goal (!) context being
  1355 used here, which is not necessarily the same as the_context().
  1356 
  1357 * Command 'find_theorems': supports "*" wild-card in "name:"
  1358 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1359 support a specific search form (see ProofGeneral/CHANGES).
  1360 
  1361 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1362 by default, which means that "prems" (and also "fixed variables") are
  1363 suppressed from proof state output.  Note that the ProofGeneral
  1364 settings mechanism allows to change and save options persistently, but
  1365 older versions of Isabelle will fail to start up if a negative prems
  1366 limit is imposed.
  1367 
  1368 * Local theory targets may be specified by non-nested blocks of
  1369 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1370 contain definitions, theorems etc., including any derived mechanism
  1371 that has been implemented on top of these primitives.  This concept
  1372 generalizes the existing ``theorem (in ...)'' towards more versatility
  1373 and scalability.
  1374 
  1375 * Proof General interface: proper undo of final 'end' command;
  1376 discontinued Isabelle/classic mode (ML proof scripts).
  1377 
  1378 
  1379 *** Document preparation ***
  1380 
  1381 * Added antiquotation @{theory name} which prints the given name,
  1382 after checking that it refers to a valid ancestor theory in the
  1383 current context.
  1384 
  1385 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1386 check the given source text as ML type/structure, printing verbatim.
  1387 
  1388 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1389 "c args == rhs" given in the current context.  (Any number of
  1390 arguments may be given on the LHS.)
  1391 
  1392 
  1393 *** Pure ***
  1394 
  1395 * The 'class' package offers a combination of axclass and locale to
  1396 achieve Haskell-like type classes in Isabelle.  Definitions and
  1397 theorems within a class context produce both relative results (with
  1398 implicit parameters according to the locale context), and polymorphic
  1399 constants with qualified polymorphism (according to the class
  1400 context).  Within the body context of a 'class' target, a separate
  1401 syntax layer ("user space type system") takes care of converting
  1402 between global polymorphic consts and internal locale representation.
  1403 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1404 "isatool doc classes" provides a tutorial.
  1405 
  1406 * Generic code generator framework allows to generate executable
  1407 code for ML and Haskell (including Isabelle classes).  A short usage
  1408 sketch:
  1409 
  1410     internal compilation:
  1411         export_code <list of constants (term syntax)> in SML
  1412     writing SML code to a file:
  1413         export_code <list of constants (term syntax)> in SML <filename>
  1414     writing OCaml code to a file:
  1415         export_code <list of constants (term syntax)> in OCaml <filename>
  1416     writing Haskell code to a bunch of files:
  1417         export_code <list of constants (term syntax)> in Haskell <filename>
  1418 
  1419     evaluating closed propositions to True/False using code generation:
  1420         method ``eval''
  1421 
  1422 Reasonable default setup of framework in HOL.
  1423 
  1424 Theorem attributs for selecting and transforming function equations theorems:
  1425 
  1426     [code fun]:        select a theorem as function equation for a specific constant
  1427     [code fun del]:    deselect a theorem as function equation for a specific constant
  1428     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1429     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1430 
  1431 User-defined serializations (target in {SML, OCaml, Haskell}):
  1432 
  1433     code_const <and-list of constants (term syntax)>
  1434       {(target) <and-list of const target syntax>}+
  1435 
  1436     code_type <and-list of type constructors>
  1437       {(target) <and-list of type target syntax>}+
  1438 
  1439     code_instance <and-list of instances>
  1440       {(target)}+
  1441         where instance ::= <type constructor> :: <class>
  1442 
  1443     code_class <and_list of classes>
  1444       {(target) <and-list of class target syntax>}+
  1445         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1446 
  1447 code_instance and code_class only are effective to target Haskell.
  1448 
  1449 For example usage see src/HOL/ex/Codegenerator.thy and
  1450 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1451 generation from Isabelle/HOL theories is available via "isatool doc
  1452 codegen".
  1453 
  1454 * Code generator: consts in 'consts_code' Isar commands are now
  1455 referred to by usual term syntax (including optional type
  1456 annotations).
  1457 
  1458 * Command 'no_translations' removes translation rules from theory
  1459 syntax.
  1460 
  1461 * Overloaded definitions are now actually checked for acyclic
  1462 dependencies.  The overloading scheme is slightly more general than
  1463 that of Haskell98, although Isabelle does not demand an exact
  1464 correspondence to type class and instance declarations.
  1465 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1466 exotic versions of overloading -- at the discretion of the user!
  1467 
  1468 Polymorphic constants are represented via type arguments, i.e. the
  1469 instantiation that matches an instance against the most general
  1470 declaration given in the signature.  For example, with the declaration
  1471 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1472 as c(nat).  Overloading is essentially simultaneous structural
  1473 recursion over such type arguments.  Incomplete specification patterns
  1474 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1475 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1476 Command 'print_theory' outputs the normalized system of recursive
  1477 equations, see section "definitions".
  1478 
  1479 * Configuration options are maintained within the theory or proof
  1480 context (with name and type bool/int/string), providing a very simple
  1481 interface to a poor-man's version of general context data.  Tools may
  1482 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1483 these values using Config.get etc.  Users may change options via an
  1484 associated attribute of the same name.  This form of context
  1485 declaration works particularly well with commands 'declare' or
  1486 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1487 very easy to avoid global references, which would not observe Isar
  1488 toplevel undo/redo and fail to work with multithreading.
  1489 
  1490 Various global ML references of Pure and HOL have been turned into
  1491 configuration options:
  1492 
  1493   Unify.search_bound		unify_search_bound
  1494   Unify.trace_bound		unify_trace_bound
  1495   Unify.trace_simp		unify_trace_simp
  1496   Unify.trace_types		unify_trace_types
  1497   Simplifier.simp_depth_limit	simp_depth_limit
  1498   Blast.depth_limit		blast_depth_limit
  1499   DatatypeProp.dtK		datatype_distinctness_limit
  1500   fast_arith_neq_limit  	fast_arith_neq_limit
  1501   fast_arith_split_limit	fast_arith_split_limit
  1502 
  1503 * Named collections of theorems may be easily installed as context
  1504 data using the functor NamedThmsFun (see also
  1505 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1506 attributes; there is also a toplevel print command.  This facility is
  1507 just a common case of general context data, which is the preferred way
  1508 for anything more complex than just a list of facts in canonical
  1509 order.
  1510 
  1511 * Isar: command 'declaration' augments a local theory by generic
  1512 declaration functions written in ML.  This enables arbitrary content
  1513 being added to the context, depending on a morphism that tells the
  1514 difference of the original declaration context wrt. the application
  1515 context encountered later on.
  1516 
  1517 * Isar: proper interfaces for simplification procedures.  Command
  1518 'simproc_setup' declares named simprocs (with match patterns, and body
  1519 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1520 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1521 
  1522 * Isar: an extra pair of brackets around attribute declarations
  1523 abbreviates a theorem reference involving an internal dummy fact,
  1524 which will be ignored later --- only the effect of the attribute on
  1525 the background context will persist.  This form of in-place
  1526 declarations is particularly useful with commands like 'declare' and
  1527 'using', for example ``have A using [[simproc a]] by simp''.
  1528 
  1529 * Isar: method "assumption" (and implicit closing of subproofs) now
  1530 takes simple non-atomic goal assumptions into account: after applying
  1531 an assumption as a rule the resulting subgoals are solved by atomic
  1532 assumption steps.  This is particularly useful to finish 'obtain'
  1533 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1534 without referring to the original premise "!!x. P x ==> thesis" in the
  1535 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1536 more permissive.
  1537 
  1538 * Isar: implicit use of prems from the Isar proof context is
  1539 considered a legacy feature.  Common applications like ``have A .''
  1540 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1541 referencing facts explicitly here improves readability and
  1542 maintainability of proof texts.
  1543 
  1544 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1545 the obtained context from the course of reasoning!  For example:
  1546 
  1547   assume "EX x y. A x & B y"   -- "any previous fact"
  1548   then guess x and y by clarify
  1549 
  1550 This technique is potentially adventurous, depending on the facts and
  1551 proof tools being involved here.
  1552 
  1553 * Isar: known facts from the proof context may be specified as literal
  1554 propositions, using ASCII back-quote syntax.  This works wherever
  1555 named facts used to be allowed so far, in proof commands, proof
  1556 methods, attributes etc.  Literal facts are retrieved from the context
  1557 according to unification of type and term parameters.  For example,
  1558 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1559 theorems in the current context, then these are valid literal facts:
  1560 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1561 
  1562 There is also a proof method "fact" which does the same composition
  1563 for explicit goal states, e.g. the following proof texts coincide with
  1564 certain special cases of literal facts:
  1565 
  1566   have "A" by fact                 ==  note `A`
  1567   have "A ==> B" by fact           ==  note `A ==> B`
  1568   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1569   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1570 
  1571 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1572 outer syntax.  Thus symbolic identifiers may be used without
  1573 additional white space in declarations like this: ``assume *: A''.
  1574 
  1575 * Isar: 'print_facts' prints all local facts of the current context,
  1576 both named and unnamed ones.
  1577 
  1578 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1579 
  1580   def x == "t" and y == "u"
  1581 
  1582 * Isar: added command 'unfolding', which is structurally similar to
  1583 'using', but affects both the goal state and facts by unfolding given
  1584 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1585 'unfolded' attribute may be replaced by first-class proof text.
  1586 
  1587 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1588 and command 'unfolding' now all support object-level equalities
  1589 (potentially conditional).  The underlying notion of rewrite rule is
  1590 analogous to the 'rule_format' attribute, but *not* that of the
  1591 Simplifier (which is usually more generous).
  1592 
  1593 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1594 premises of a theorem by n. Useful in conjunction with drule.
  1595 
  1596 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1597 method expression within a sandbox consisting of the first N
  1598 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1599 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1600 simplifies all new goals that emerge from applying rule foo to the
  1601 originally first one.
  1602 
  1603 * Isar: schematic goals are no longer restricted to higher-order
  1604 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1605 expected.
  1606 
  1607 * Isar: the conclusion of a long theorem statement is now either
  1608 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1609 (essentially a disjunction of cases with local parameters and
  1610 assumptions).  The latter allows to express general elimination rules
  1611 adequately; in this notation common elimination rules look like this:
  1612 
  1613   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1614     assumes "EX x. P x"
  1615     obtains x where "P x"
  1616 
  1617   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1618     assumes "A & B"
  1619     obtains A and B
  1620 
  1621   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1622     assumes "A | B"
  1623     obtains
  1624       A
  1625     | B
  1626 
  1627 The subsequent classical rules even refer to the formal "thesis"
  1628 explicitly:
  1629 
  1630   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1631     obtains "~ thesis"
  1632 
  1633   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1634     obtains "thesis ==> something"
  1635 
  1636 The actual proof of an 'obtains' statement is analogous to that of the
  1637 Isar proof element 'obtain', only that there may be several cases.
  1638 Optional case names may be specified in parentheses; these will be
  1639 available both in the present proof and as annotations in the
  1640 resulting rule, for later use with the 'cases' method (cf. attribute
  1641 case_names).
  1642 
  1643 * Isar: the assumptions of a long theorem statement are available as
  1644 "assms" fact in the proof context.  This is more appropriate than the
  1645 (historical) "prems", which refers to all assumptions of the current
  1646 context, including those from the target locale, proof body etc.
  1647 
  1648 * Isar: 'print_statement' prints theorems from the current theory or
  1649 proof context in long statement form, according to the syntax of a
  1650 top-level lemma.
  1651 
  1652 * Isar: 'obtain' takes an optional case name for the local context
  1653 introduction rule (default "that").
  1654 
  1655 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1656 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1657 to occur.
  1658 
  1659 * Pure: syntax "CONST name" produces a fully internalized constant
  1660 according to the current context.  This is particularly useful for
  1661 syntax translations that should refer to internal constant
  1662 representations independently of name spaces.
  1663 
  1664 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1665 instead of "FOO ". This allows multiple binder declarations to coexist
  1666 in the same context.  INCOMPATIBILITY.
  1667 
  1668 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1669 primitive that also works in a locale context (both for constants and
  1670 fixed variables). Type declaration and internal syntactic representation
  1671 of given constants retrieved from the context. Likewise, the
  1672 'no_notation' command allows to remove given syntax annotations from the
  1673 current context.
  1674 
  1675 * Isar/locales: new derived specification elements 'axiomatization',
  1676 'definition', 'abbreviation', which support type-inference, admit
  1677 object-level specifications (equality, equivalence).  See also the
  1678 isar-ref manual.  Examples:
  1679 
  1680   axiomatization
  1681     eq  (infix "===" 50) where
  1682     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1683 
  1684   definition "f x y = x + y + 1"
  1685   definition g where "g x = f x x"
  1686 
  1687   abbreviation
  1688     neq  (infix "=!=" 50) where
  1689     "x =!= y == ~ (x === y)"
  1690 
  1691 These specifications may be also used in a locale context.  Then the
  1692 constants being introduced depend on certain fixed parameters, and the
  1693 constant name is qualified by the locale base name.  An internal
  1694 abbreviation takes care for convenient input and output, making the
  1695 parameters implicit and using the original short name.  See also
  1696 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1697 entities from a monomorphic theory.
  1698 
  1699 Presently, abbreviations are only available 'in' a target locale, but
  1700 not inherited by general import expressions.  Also note that
  1701 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1702 'translations' in common applications.  The "no_abbrevs" print mode
  1703 prevents folding of abbreviations in term output.
  1704 
  1705 Concrete syntax is attached to specified constants in internal form,
  1706 independently of name spaces.  The parse tree representation is
  1707 slightly different -- use 'notation' instead of raw 'syntax', and
  1708 'translations' with explicit "CONST" markup to accommodate this.
  1709 
  1710 * Pure/Isar: unified syntax for new-style specification mechanisms
  1711 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1712 full type inference and dummy patterns ("_").  For example:
  1713 
  1714   definition "K x _ = x"
  1715 
  1716   inductive conj for A B
  1717   where "A ==> B ==> conj A B"
  1718 
  1719 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1720 the current context.  Print mode "no_abbrevs" prevents inversion of
  1721 abbreviations on output.
  1722 
  1723 * Isar/locales: improved parameter handling: use of locales "var" and
  1724 "struct" no longer necessary; - parameter renamings are no longer
  1725 required to be injective.  For example, this allows to define
  1726 endomorphisms as locale endom = homom mult mult h.
  1727 
  1728 * Isar/locales: changed the way locales with predicates are defined.
  1729 Instead of accumulating the specification, the imported expression is
  1730 now an interpretation.  INCOMPATIBILITY: different normal form of
  1731 locale expressions.  In particular, in interpretations of locales with
  1732 predicates, goals repesenting already interpreted fragments are not
  1733 removed automatically.  Use methods `intro_locales' and
  1734 `unfold_locales'; see below.
  1735 
  1736 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1737 provide backward reasoning on locales predicates.  The methods are
  1738 aware of interpretations and discharge corresponding goals.
  1739 `intro_locales' is less aggressive then `unfold_locales' and does not
  1740 unfold predicates to assumptions.
  1741 
  1742 * Isar/locales: the order in which locale fragments are accumulated
  1743 has changed.  This enables to override declarations from fragments due
  1744 to interpretations -- for example, unwanted simp rules.
  1745 
  1746 * Isar/locales: interpretation in theories and proof contexts has been
  1747 extended.  One may now specify (and prove) equations, which are
  1748 unfolded in interpreted theorems.  This is useful for replacing
  1749 defined concepts (constants depending on locale parameters) by
  1750 concepts already existing in the target context.  Example:
  1751 
  1752   interpretation partial_order ["op <= :: [int, int] => bool"]
  1753     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1754 
  1755 Typically, the constant `partial_order.less' is created by a
  1756 definition specification element in the context of locale
  1757 partial_order.
  1758 
  1759 * Method "induct": improved internal context management to support
  1760 local fixes and defines on-the-fly. Thus explicit meta-level
  1761 connectives !!  and ==> are rarely required anymore in inductive goals
  1762 (using object-logic connectives for this purpose has been long
  1763 obsolete anyway). Common proof patterns are explained in
  1764 src/HOL/Induct/Common_Patterns.thy, see also
  1765 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1766 examples.
  1767 
  1768 * Method "induct": improved handling of simultaneous goals. Instead of
  1769 introducing object-level conjunction, the statement is now split into
  1770 several conclusions, while the corresponding symbolic cases are nested
  1771 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1772 see src/HOL/Induct/Common_Patterns.thy, for example.
  1773 
  1774 * Method "induct": mutual induction rules are now specified as a list
  1775 of rule sharing the same induction cases. HOL packages usually provide
  1776 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1777 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1778 mutual induction rules differently, i.e. like this:
  1779 
  1780   (induct rule: foo_bar.inducts)
  1781   (induct set: foo bar)
  1782   (induct pred: foo bar)
  1783   (induct type: foo bar)
  1784 
  1785 The ML function ProjectRule.projections turns old-style rules into the
  1786 new format.
  1787 
  1788 * Method "coinduct": dual of induction, see
  1789 src/HOL/Library/Coinductive_List.thy for various examples.
  1790 
  1791 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1792 considered a legacy feature.
  1793 
  1794 * Attribute "symmetric" produces result with standardized schematic
  1795 variables (index 0).  Potential INCOMPATIBILITY.
  1796 
  1797 * Simplifier: by default the simplifier trace only shows top level
  1798 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1799 default. Thus there is less danger of being flooded by the trace. The
  1800 trace indicates where parts have been suppressed.
  1801   
  1802 * Provers/classical: removed obsolete classical version of elim_format
  1803 attribute; classical elim/dest rules are now treated uniformly when
  1804 manipulating the claset.
  1805 
  1806 * Provers/classical: stricter checks to ensure that supplied intro,
  1807 dest and elim rules are well-formed; dest and elim rules must have at
  1808 least one premise.
  1809 
  1810 * Provers/classical: attributes dest/elim/intro take an optional
  1811 weight argument for the rule (just as the Pure versions).  Weights are
  1812 ignored by automated tools, but determine the search order of single
  1813 rule steps.
  1814 
  1815 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1816 where the body does not mention the bound variable.  Note that dummy
  1817 patterns implicitly depend on their context of bounds, which makes
  1818 "{_. _}" match any set comprehension as expected.  Potential
  1819 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1820 constant "_idtdummy" in the binding position.
  1821 
  1822 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1823 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1824 for example "A -> B" => "Pi A (%_. B)".
  1825 
  1826 * Pure: 'class_deps' command visualizes the subclass relation, using
  1827 the graph browser tool.
  1828 
  1829 * Pure: 'print_theory' now suppresses certain internal declarations by
  1830 default; use '!' option for full details.
  1831 
  1832 
  1833 *** HOL ***
  1834 
  1835 * Method "metis" proves goals by applying the Metis general-purpose
  1836 resolution prover (see also http://gilith.com/software/metis/).
  1837 Examples are in the directory MetisExamples.  WARNING: the
  1838 Isabelle/HOL-Metis integration does not yet work properly with
  1839 multi-threading.
  1840   
  1841 * Command 'sledgehammer' invokes external automatic theorem provers as
  1842 background processes.  It generates calls to the "metis" method if
  1843 successful. These can be pasted into the proof.  Users do not have to
  1844 wait for the automatic provers to return.  WARNING: does not really
  1845 work with multi-threading.
  1846 
  1847 * New "auto_quickcheck" feature tests outermost goal statements for
  1848 potential counter-examples.  Controlled by ML references
  1849 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1850 5000 milliseconds).  Fails silently if statements is outside of
  1851 executable fragment, or any other codgenerator problem occurs.
  1852 
  1853 * New constant "undefined" with axiom "undefined x = undefined".
  1854 
  1855 * Added class "HOL.eq", allowing for code generation with polymorphic
  1856 equality.
  1857 
  1858 * Some renaming of class constants due to canonical name prefixing in
  1859 the new 'class' package:
  1860 
  1861     HOL.abs ~> HOL.abs_class.abs
  1862     HOL.divide ~> HOL.divide_class.divide
  1863     0 ~> HOL.zero_class.zero
  1864     1 ~> HOL.one_class.one
  1865     op + ~> HOL.plus_class.plus
  1866     op - ~> HOL.minus_class.minus
  1867     uminus ~> HOL.minus_class.uminus
  1868     op * ~> HOL.times_class.times
  1869     op < ~> HOL.ord_class.less
  1870     op <= > HOL.ord_class.less_eq
  1871     Nat.power ~> Power.power_class.power
  1872     Nat.size ~> Nat.size_class.size
  1873     Numeral.number_of ~> Numeral.number_class.number_of
  1874     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1875     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1876     Orderings.min ~> Orderings.ord_class.min
  1877     Orderings.max ~> Orderings.ord_class.max
  1878     Divides.op div ~> Divides.div_class.div
  1879     Divides.op mod ~> Divides.div_class.mod
  1880     Divides.op dvd ~> Divides.div_class.dvd
  1881 
  1882 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1883 
  1884 a) User-defined constants using any of the names "plus", "minus",
  1885 "times", "less" or "less_eq". The standard syntax translations for
  1886 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1887 names.
  1888 
  1889 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1890 INCOMPATIBILITY: use more specific names.
  1891 
  1892 c) Permutative equations (e.g. "a + b = b + a")
  1893 Since the change of names also changes the order of terms, permutative
  1894 rewrite rules may get applied in a different order. Experience shows
  1895 that this is rarely the case (only two adaptions in the whole Isabelle
  1896 distribution).  INCOMPATIBILITY: rewrite proofs
  1897 
  1898 d) ML code directly refering to constant names
  1899 This in general only affects hand-written proof tactics, simprocs and
  1900 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1901 Consider using @{const_name} antiquotation.
  1902 
  1903 * New class "default" with associated constant "default".
  1904 
  1905 * Function "sgn" is now overloaded and available on int, real, complex
  1906 (and other numeric types), using class "sgn".  Two possible defs of
  1907 sgn are given as equational assumptions in the classes sgn_if and
  1908 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1909 INCOMPATIBILITY.
  1910 
  1911 * Locale "partial_order" now unified with class "order" (cf. theory
  1912 Orderings), added parameter "less".  INCOMPATIBILITY.
  1913 
  1914 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1915 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1916 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1917 
  1918 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1919 changed order of proof goals in instance proofs.
  1920 
  1921 * The transitivity reasoner for partial and linear orders is set up
  1922 for classes "order" and "linorder".  Instances of the reasoner are available
  1923 in all contexts importing or interpreting the corresponding locales.
  1924 Method "order" invokes the reasoner separately; the reasoner
  1925 is also integrated with the Simplifier as a solver.  Diagnostic
  1926 command 'print_orders' shows the available instances of the reasoner
  1927 in the current context.
  1928 
  1929 * Localized monotonicity predicate in theory "Orderings"; integrated
  1930 lemmas max_of_mono and min_of_mono with this predicate.
  1931 INCOMPATIBILITY.
  1932 
  1933 * Formulation of theorem "dense" changed slightly due to integration
  1934 with new class dense_linear_order.
  1935 
  1936 * Uniform lattice theory development in HOL.
  1937 
  1938     constants "meet" and "join" now named "inf" and "sup"
  1939     constant "Meet" now named "Inf"
  1940 
  1941     classes "meet_semilorder" and "join_semilorder" now named
  1942       "lower_semilattice" and "upper_semilattice"
  1943     class "lorder" now named "lattice"
  1944     class "comp_lat" now named "complete_lattice"
  1945 
  1946     Instantiation of lattice classes allows explicit definitions
  1947     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1948 
  1949   INCOMPATIBILITY.  Theorem renames:
  1950 
  1951     meet_left_le            ~> inf_le1
  1952     meet_right_le           ~> inf_le2
  1953     join_left_le            ~> sup_ge1
  1954     join_right_le           ~> sup_ge2
  1955     meet_join_le            ~> inf_sup_ord
  1956     le_meetI                ~> le_infI
  1957     join_leI                ~> le_supI
  1958     le_meet                 ~> le_inf_iff
  1959     le_join                 ~> ge_sup_conv
  1960     meet_idempotent         ~> inf_idem
  1961     join_idempotent         ~> sup_idem
  1962     meet_comm               ~> inf_commute
  1963     join_comm               ~> sup_commute
  1964     meet_leI1               ~> le_infI1
  1965     meet_leI2               ~> le_infI2
  1966     le_joinI1               ~> le_supI1
  1967     le_joinI2               ~> le_supI2
  1968     meet_assoc              ~> inf_assoc
  1969     join_assoc              ~> sup_assoc
  1970     meet_left_comm          ~> inf_left_commute
  1971     meet_left_idempotent    ~> inf_left_idem
  1972     join_left_comm          ~> sup_left_commute
  1973     join_left_idempotent    ~> sup_left_idem
  1974     meet_aci                ~> inf_aci
  1975     join_aci                ~> sup_aci
  1976     le_def_meet             ~> le_iff_inf
  1977     le_def_join             ~> le_iff_sup
  1978     join_absorp2            ~> sup_absorb2
  1979     join_absorp1            ~> sup_absorb1
  1980     meet_absorp1            ~> inf_absorb1
  1981     meet_absorp2            ~> inf_absorb2
  1982     meet_join_absorp        ~> inf_sup_absorb
  1983     join_meet_absorp        ~> sup_inf_absorb
  1984     distrib_join_le         ~> distrib_sup_le
  1985     distrib_meet_le         ~> distrib_inf_le
  1986 
  1987     add_meet_distrib_left   ~> add_inf_distrib_left
  1988     add_join_distrib_left   ~> add_sup_distrib_left
  1989     is_join_neg_meet        ~> is_join_neg_inf
  1990     is_meet_neg_join        ~> is_meet_neg_sup
  1991     add_meet_distrib_right  ~> add_inf_distrib_right
  1992     add_join_distrib_right  ~> add_sup_distrib_right
  1993     add_meet_join_distribs  ~> add_sup_inf_distribs
  1994     join_eq_neg_meet        ~> sup_eq_neg_inf
  1995     meet_eq_neg_join        ~> inf_eq_neg_sup
  1996     add_eq_meet_join        ~> add_eq_inf_sup
  1997     meet_0_imp_0            ~> inf_0_imp_0
  1998     join_0_imp_0            ~> sup_0_imp_0
  1999     meet_0_eq_0             ~> inf_0_eq_0
  2000     join_0_eq_0             ~> sup_0_eq_0
  2001     neg_meet_eq_join        ~> neg_inf_eq_sup
  2002     neg_join_eq_meet        ~> neg_sup_eq_inf
  2003     join_eq_if              ~> sup_eq_if
  2004 
  2005     mono_meet               ~> mono_inf
  2006     mono_join               ~> mono_sup
  2007     meet_bool_eq            ~> inf_bool_eq
  2008     join_bool_eq            ~> sup_bool_eq
  2009     meet_fun_eq             ~> inf_fun_eq
  2010     join_fun_eq             ~> sup_fun_eq
  2011     meet_set_eq             ~> inf_set_eq
  2012     join_set_eq             ~> sup_set_eq
  2013     meet1_iff               ~> inf1_iff
  2014     meet2_iff               ~> inf2_iff
  2015     meet1I                  ~> inf1I
  2016     meet2I                  ~> inf2I
  2017     meet1D1                 ~> inf1D1
  2018     meet2D1                 ~> inf2D1
  2019     meet1D2                 ~> inf1D2
  2020     meet2D2                 ~> inf2D2
  2021     meet1E                  ~> inf1E
  2022     meet2E                  ~> inf2E
  2023     join1_iff               ~> sup1_iff
  2024     join2_iff               ~> sup2_iff
  2025     join1I1                 ~> sup1I1
  2026     join2I1                 ~> sup2I1
  2027     join1I1                 ~> sup1I1
  2028     join2I2                 ~> sup1I2
  2029     join1CI                 ~> sup1CI
  2030     join2CI                 ~> sup2CI
  2031     join1E                  ~> sup1E
  2032     join2E                  ~> sup2E
  2033 
  2034     is_meet_Meet            ~> is_meet_Inf
  2035     Meet_bool_def           ~> Inf_bool_def
  2036     Meet_fun_def            ~> Inf_fun_def
  2037     Meet_greatest           ~> Inf_greatest
  2038     Meet_lower              ~> Inf_lower
  2039     Meet_set_def            ~> Inf_set_def
  2040 
  2041     Sup_def                 ~> Sup_Inf
  2042     Sup_bool_eq             ~> Sup_bool_def
  2043     Sup_fun_eq              ~> Sup_fun_def
  2044     Sup_set_eq              ~> Sup_set_def
  2045 
  2046     listsp_meetI            ~> listsp_infI
  2047     listsp_meet_eq          ~> listsp_inf_eq
  2048 
  2049     meet_min                ~> inf_min
  2050     join_max                ~> sup_max
  2051 
  2052 * Added syntactic class "size"; overloaded constant "size" now has
  2053 type "'a::size ==> bool"
  2054 
  2055 * Internal reorganisation of `size' of datatypes: size theorems
  2056 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2057 simplification rules by default!); theorems "prod.size" now named
  2058 "*.size".
  2059 
  2060 * Class "div" now inherits from class "times" rather than "type".
  2061 INCOMPATIBILITY.
  2062 
  2063 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2064 Linorder etc.  have disappeared; operations defined in terms of
  2065 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2066 
  2067 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2068 
  2069 * HOL-Word: New extensive library and type for generic, fixed size
  2070 machine words, with arithemtic, bit-wise, shifting and rotating
  2071 operations, reflection into int, nat, and bool lists, automation for
  2072 linear arithmetic (by automatic reflection into nat or int), including
  2073 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2074 arithmetic type classes, supporting automatic simplification of
  2075 numerals on all operations.
  2076 
  2077 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2078 
  2079 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2080 
  2081 * Code generator library theories:
  2082   - Code_Integer represents HOL integers by big integer literals in target
  2083     languages.
  2084   - Code_Char represents HOL characters by character literals in target
  2085     languages.
  2086   - Code_Char_chr like Code_Char, but also offers treatment of character
  2087     codes; includes Code_Integer.
  2088   - Executable_Set allows to generate code for finite sets using lists.
  2089   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2090     denominator).
  2091   - Executable_Real implements a subset of real numbers, namly those
  2092     representable by rational numbers.
  2093   - Efficient_Nat implements natural numbers by integers, which in general will
  2094     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2095     includes Code_Integer.
  2096   - Code_Index provides an additional datatype index which is mapped to
  2097     target-language built-in integers.
  2098   - Code_Message provides an additional datatype message_string which is isomorphic to
  2099     strings; messages are mapped to target-language strings.
  2100 
  2101 * New package for inductive predicates
  2102 
  2103   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2104 
  2105     inductive
  2106       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2107       for z_1 :: U_1 and ... and z_n :: U_m
  2108     where
  2109       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2110     | ...
  2111 
  2112   with full support for type-inference, rather than
  2113 
  2114     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2115 
  2116     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2117     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2118 
  2119     inductive "s z_1 ... z_m"
  2120     intros
  2121       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2122       ...
  2123 
  2124   For backward compatibility, there is a wrapper allowing inductive
  2125   sets to be defined with the new package via
  2126 
  2127     inductive_set
  2128       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2129       for z_1 :: U_1 and ... and z_n :: U_m
  2130     where
  2131       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2132     | ...
  2133 
  2134   or
  2135 
  2136     inductive_set
  2137       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2138       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2139       for z_1 :: U_1 and ... and z_n :: U_m
  2140     where
  2141       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2142     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2143     | ...
  2144 
  2145   if the additional syntax "p ..." is required.
  2146 
  2147   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2148   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2149 
  2150   INCOMPATIBILITIES:
  2151 
  2152   - Since declaration and definition of inductive sets or predicates
  2153     is no longer separated, abbreviations involving the newly
  2154     introduced sets or predicates must be specified together with the
  2155     introduction rules after the 'where' keyword (see above), rather
  2156     than before the actual inductive definition.
  2157 
  2158   - The variables in induction and elimination rules are now
  2159     quantified in the order of their occurrence in the introduction
  2160     rules, rather than in alphabetical order. Since this may break
  2161     some proofs, these proofs either have to be repaired, e.g. by
  2162     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2163     statements of the form
  2164 
  2165       case (rule_i a_i_1 ... a_i_{k_i})
  2166 
  2167     or the old order of quantification has to be restored by explicitly adding
  2168     meta-level quantifiers in the introduction rules, i.e.
  2169 
  2170       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2171 
  2172   - The format of the elimination rules is now
  2173 
  2174       p z_1 ... z_m x_1 ... x_n ==>
  2175         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2176         ==> ... ==> P
  2177 
  2178     for predicates and
  2179 
  2180       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2181         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2182         ==> ... ==> P
  2183 
  2184     for sets rather than
  2185 
  2186       x : s z_1 ... z_m ==>
  2187         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2188         ==> ... ==> P
  2189 
  2190     This may require terms in goals to be expanded to n-tuples
  2191     (e.g. using case_tac or simplification with the split_paired_all
  2192     rule) before the above elimination rule is applicable.
  2193 
  2194   - The elimination or case analysis rules for (mutually) inductive
  2195     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2196     list of rules "p_1_..._p_k.elims" is no longer available.
  2197 
  2198 * New package "function"/"fun" for general recursive functions,
  2199 supporting mutual and nested recursion, definitions in local contexts,
  2200 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2201 for small examples, and the separate tutorial on the function
  2202 package. The old recdef "package" is still available as before, but
  2203 users are encouraged to use the new package.
  2204 
  2205 * Method "lexicographic_order" automatically synthesizes termination
  2206 relations as lexicographic combinations of size measures. 
  2207 
  2208 * Case-expressions allow arbitrary constructor-patterns (including
  2209 "_") and take their order into account, like in functional
  2210 programming.  Internally, this is translated into nested
  2211 case-expressions; missing cases are added and mapped to the predefined
  2212 constant "undefined". In complicated cases printing may no longer show
  2213 the original input but the internal form. Lambda-abstractions allow
  2214 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2215 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2216 variable.
  2217 
  2218 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2219 is an abbreviation for "of_nat :: nat => int". The simplification
  2220 rules for "of_nat" have been changed to work like "int" did
  2221 previously.  Potential INCOMPATIBILITY:
  2222   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2223   - of_nat_diff and of_nat_mult are no longer default simp rules
  2224 
  2225 * Method "algebra" solves polynomial equations over (semi)rings using
  2226 Groebner bases. The (semi)ring structure is defined by locales and the
  2227 tool setup depends on that generic context. Installing the method for
  2228 a specific type involves instantiating the locale and possibly adding
  2229 declarations for computation on the coefficients.  The method is
  2230 already instantiated for natural numbers and for the axiomatic class
  2231 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2232 CALCULEMUS 2007 for the general principles underlying this
  2233 architecture of context-aware proof-tools.
  2234 
  2235 * Method "ferrack" implements quantifier elimination over
  2236 special-purpose dense linear orders using locales (analogous to
  2237 "algebra"). The method is already installed for class
  2238 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2239 rat, etc.
  2240 
  2241 * Former constant "List.op @" now named "List.append".  Use ML
  2242 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2243 circumvent possible incompatibilities when working on ML level.
  2244 
  2245 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2246 
  2247 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2248 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2249 
  2250 * New syntax for Haskell-like list comprehension (input only), eg.
  2251 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2252 
  2253 * The special syntax for function "filter" has changed from [x :
  2254 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2255 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2256 
  2257 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2258 defined on nat only, as an abbreviation for [a..<Suc b]
  2259 INCOMPATIBILITY.
  2260 
  2261 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2262 
  2263 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2264 
  2265 * New lemma collection field_simps (an extension of ring_simps) for
  2266 manipulating (in)equations involving division. Multiplies with all
  2267 denominators that can be proved to be non-zero (in equations) or
  2268 positive/negative (in inequations).
  2269 
  2270 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2271 have been improved and renamed to ring_simps, group_simps and
  2272 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2273 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2274 
  2275 * Theory Library/Commutative_Ring: switched from recdef to function
  2276 package; constants add, mul, pow now curried.  Infix syntax for
  2277 algebraic operations.
  2278 
  2279 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2280 INCOMPATIBILITY.
  2281 
  2282 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2283 INCOMPATIBILITY.
  2284 
  2285 * HOL/records: generalised field-update to take a function on the
  2286 field rather than the new value: r(|A := x|) is translated to A_update
  2287 (K x) r The K-combinator that is internally used is called K_record.
  2288 INCOMPATIBILITY: Usage of the plain update functions has to be
  2289 adapted.
  2290  
  2291 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2292 * x = 0, which are required for a semiring.  Richer structures do not
  2293 inherit from semiring_0 anymore, because this property is a theorem
  2294 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2295 there is more to prove, but this is mostly trivial.
  2296 
  2297 * Class "recpower" is generalized to arbitrary monoids, not just
  2298 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2299 commutativity or semiring properties additionally.
  2300 
  2301 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2302 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2303 better use 'abbreviation'.
  2304 
  2305 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2306 
  2307 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2308 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2309 significant changes for setting up numeral syntax for types:
  2310   - New constants Numeral.pred and Numeral.succ instead
  2311       of former Numeral.bin_pred and Numeral.bin_succ.
  2312   - Use integer operations instead of bin_add, bin_mult and so on.
  2313   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2314   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2315 
  2316 See src/HOL/Integ/IntArith.thy for an example setup.
  2317 
  2318 * Command 'normal_form' computes the normal form of a term that may
  2319 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2320 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2321 heavy-duty computations because the functions are compiled to ML
  2322 first.  Correspondingly, a method "normalization" is provided.  See
  2323 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2324 
  2325 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2326 25 like -->); output depends on the "iff" print_mode, the default is
  2327 "A = B" (with priority 50).
  2328 
  2329 * Relations less (<) and less_eq (<=) are also available on type bool.
  2330 Modified syntax to disallow nesting without explicit parentheses,
  2331 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2332 INCOMPATIBILITY.
  2333 
  2334 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2335 
  2336 * Relation composition operator "op O" now has precedence 75 and binds
  2337 stronger than union and intersection. INCOMPATIBILITY.
  2338 
  2339 * The old set interval syntax "{m..n(}" (and relatives) has been
  2340 removed.  Use "{m..<n}" (and relatives) instead.
  2341 
  2342 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2343 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2344 ``declare [[simproc del: neq]]''.
  2345 
  2346 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2347 True/False.
  2348 
  2349 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2350 
  2351 * Theorem setsum_mult renamed to setsum_right_distrib.
  2352 
  2353 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2354 ``rule'' method.
  2355 
  2356 * Reimplemented methods "sat" and "satx", with several improvements:
  2357 goals no longer need to be stated as "<prems> ==> False", equivalences
  2358 (i.e. "=" on type bool) are handled, variable names of the form
  2359 "lit_<n>" are no longer reserved, significant speedup.
  2360 
  2361 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2362 zChaff is still supported as well.
  2363 
  2364 * 'inductive' and 'datatype': provide projections of mutual rules,
  2365 bundled as foo_bar.inducts;
  2366 
  2367 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2368 Library.
  2369 
  2370 * Library: moved theory Accessible_Part to main HOL.
  2371 
  2372 * Library: added theory Coinductive_List of potentially infinite lists
  2373 as greatest fixed-point.
  2374 
  2375 * Library: added theory AssocList which implements (finite) maps as
  2376 association lists.
  2377 
  2378 * Method "evaluation" solves goals (i.e. a boolean expression)
  2379 efficiently by compiling it to ML.  The goal is "proved" (via an
  2380 oracle) if it evaluates to True.
  2381 
  2382 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2383 also when invoked by the simplifier.  This results in the Simplifier
  2384 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2385 Configuration option fast_arith_split_limit=0 recovers the old
  2386 behavior.
  2387 
  2388 * Support for hex (0x20) and binary (0b1001) numerals.
  2389 
  2390 * New method: reify eqs (t), where eqs are equations for an
  2391 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2392 parameter, computes a term s::'b and a list xs::'a list and proves the
  2393 theorem I xs s = t. This is also known as reification or quoting. The
  2394 resulting theorem is applied to the subgoal to substitute t with I xs
  2395 s.  If t is omitted, the subgoal itself is reified.
  2396 
  2397 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2398 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2399 where f is supposed to be a computable function (in the sense of code
  2400 generattion). The method uses reify to compute s and xs as above then
  2401 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2402 r and finally gets the theorem t = r, which is again applied to the
  2403 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2404 
  2405 * Reflection: Automatic reification now handels binding, an example is
  2406 available in src/HOL/ex/ReflectionEx.thy
  2407 
  2408 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2409 command 'statespace' that is similar to 'record', but introduces an
  2410 abstract specification based on the locale infrastructure instead of
  2411 HOL types.  This leads to extra flexibility in composing state spaces,
  2412 in particular multiple inheritance and renaming of components.
  2413 
  2414 
  2415 *** HOL-Complex ***
  2416 
  2417 * Hyperreal: Functions root and sqrt are now defined on negative real
  2418 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2419 Nonnegativity side conditions have been removed from many lemmas, so
  2420 that more subgoals may now be solved by simplification; potential
  2421 INCOMPATIBILITY.
  2422 
  2423 * Real: new type classes formalize real normed vector spaces and
  2424 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2425 and norm :: 'a => real.
  2426 
  2427 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2428 reals into other types. The overloaded constant Reals :: 'a set is now
  2429 defined as range of_real; potential INCOMPATIBILITY.
  2430 
  2431 * Real: proper support for ML code generation, including 'quickcheck'.
  2432 Reals are implemented as arbitrary precision rationals.
  2433 
  2434 * Hyperreal: Several constants that previously worked only for the
  2435 reals have been generalized, so they now work over arbitrary vector
  2436 spaces. Type annotations may need to be added in some cases; potential
  2437 INCOMPATIBILITY.
  2438 
  2439   Infinitesimal  :: ('a::real_normed_vector) star set
  2440   HFinite        :: ('a::real_normed_vector) star set
  2441   HInfinite      :: ('a::real_normed_vector) star set
  2442   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2443   monad          :: ('a::real_normed_vector) star => 'a star set
  2444   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2445   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2446   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2447   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2448   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2449   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2450   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2451   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2452   sgn            :: 'a::real_normed_vector => 'a
  2453   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2454 
  2455 * Complex: Some complex-specific constants are now abbreviations for
  2456 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2457 hnorm.  Other constants have been entirely removed in favor of the
  2458 polymorphic versions (INCOMPATIBILITY):
  2459 
  2460   approx        <-- capprox
  2461   HFinite       <-- CFinite
  2462   HInfinite     <-- CInfinite
  2463   Infinitesimal <-- CInfinitesimal
  2464   monad         <-- cmonad
  2465   galaxy        <-- cgalaxy
  2466   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2467   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2468   (ns)deriv     <-- (ns)cderiv
  2469 
  2470 
  2471 *** HOL-Algebra ***
  2472 
  2473 * Formalisation of ideals and the quotient construction over rings.
  2474 
  2475 * Order and lattice theory no longer based on records.
  2476 INCOMPATIBILITY.
  2477 
  2478 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2479 greatest_closed.  INCOMPATIBILITY.
  2480 
  2481 * Method algebra is now set up via an attribute.  For examples see
  2482 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2483 of algebraic structures.
  2484 
  2485 * Renamed theory CRing to Ring.
  2486 
  2487 
  2488 *** HOL-Nominal ***
  2489 
  2490 * Substantial, yet incomplete support for nominal datatypes (binding
  2491 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2492 src/HOL/Nominal/Examples.  Prospective users should consult
  2493 http://isabelle.in.tum.de/nominal/
  2494 
  2495 
  2496 *** ML ***
  2497 
  2498 * ML basics: just one true type int, which coincides with IntInf.int
  2499 (even on SML/NJ).
  2500 
  2501 * ML within Isar: antiquotations allow to embed statically-checked
  2502 formal entities in the source, referring to the context available at
  2503 compile-time.  For example:
  2504 
  2505 ML {* @{sort "{zero,one}"} *}
  2506 ML {* @{typ "'a => 'b"} *}
  2507 ML {* @{term "%x. x"} *}
  2508 ML {* @{prop "x == y"} *}
  2509 ML {* @{ctyp "'a => 'b"} *}
  2510 ML {* @{cterm "%x. x"} *}
  2511 ML {* @{cprop "x == y"} *}
  2512 ML {* @{thm asm_rl} *}
  2513 ML {* @{thms asm_rl} *}
  2514 ML {* @{type_name c} *}
  2515 ML {* @{type_syntax c} *}
  2516 ML {* @{const_name c} *}
  2517 ML {* @{const_syntax c} *}
  2518 ML {* @{context} *}
  2519 ML {* @{theory} *}
  2520 ML {* @{theory Pure} *}
  2521 ML {* @{theory_ref} *}
  2522 ML {* @{theory_ref Pure} *}
  2523 ML {* @{simpset} *}
  2524 ML {* @{claset} *}
  2525 ML {* @{clasimpset} *}
  2526 
  2527 The same works for sources being ``used'' within an Isar context.
  2528 
  2529 * ML in Isar: improved error reporting; extra verbosity with
  2530 ML_Context.trace enabled.
  2531 
  2532 * Pure/General/table.ML: the join operations now works via exceptions
  2533 DUP/SAME instead of type option. This is simpler in simple cases, and
  2534 admits slightly more efficient complex applications.
  2535 
  2536 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2537 use Context.generic instead of just theory.
  2538 
  2539 * Pure: datatype Context.generic joins theory/Proof.context and
  2540 provides some facilities for code that works in either kind of
  2541 context, notably GenericDataFun for uniform theory and proof data.
  2542 
  2543 * Pure: simplified internal attribute type, which is now always
  2544 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2545 local (Proof.context) attributes have been discontinued, while
  2546 minimizing code duplication. Thm.rule_attribute and
  2547 Thm.declaration_attribute build canonical attributes; see also structure
  2548 Context for further operations on Context.generic, notably
  2549 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2550 declarations and definitions.
  2551 
  2552 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2553 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2554 init only required for impure data. INCOMPATIBILITY: empty really need
  2555 to be empty (no dependencies on theory content!)
  2556 
  2557 * Pure/kernel: consts certification ignores sort constraints given in
  2558 signature declarations. (This information is not relevant to the
  2559 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2560 potential INCOMPATIBILITY.
  2561 
  2562 * Pure: axiomatic type classes are now purely definitional, with
  2563 explicit proofs of class axioms and super class relations performed
  2564 internally. See Pure/axclass.ML for the main internal interfaces --
  2565 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2566 AxClass.axiomatize_class/classrel/arity supersede
  2567 Sign.add_classes/classrel/arities.
  2568 
  2569 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2570 global/local versions on theory vs. Proof.context have been
  2571 discontinued; Attrib.syntax and Method.syntax have been adapted
  2572 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2573 attributes, methods, etc.
  2574 
  2575 * Pure: several functions of signature "... -> theory -> theory * ..."
  2576 have been reoriented to "... -> theory -> ... * theory" in order to
  2577 allow natural usage in combination with the ||>, ||>>, |-> and
  2578 fold_map combinators.
  2579 
  2580 * Pure: official theorem names (closed derivations) and additional
  2581 comments (tags) are now strictly separate.  Name hints -- which are
  2582 maintained as tags -- may be attached any time without affecting the
  2583 derivation.
  2584 
  2585 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2586 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2587 achieve the old behaviour.
  2588 
  2589 * Pure: the "Goal" constant is now called "prop", supporting a
  2590 slightly more general idea of ``protecting'' meta-level rule
  2591 statements.
  2592 
  2593 * Pure: Logic.(un)varify only works in a global context, which is now
  2594 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2595 Logic.legacy_(un)varify as temporary workaround.
  2596 
  2597 * Pure: structure Name provides scalable operations for generating
  2598 internal variable names, notably Name.variants etc.  This replaces
  2599 some popular functions from term.ML:
  2600 
  2601   Term.variant		->  Name.variant
  2602   Term.variantlist	->  Name.variant_list
  2603   Term.invent_names	->  Name.invent_list
  2604 
  2605 Note that low-level renaming rarely occurs in new code -- operations
  2606 from structure Variable are used instead (see below).
  2607 
  2608 * Pure: structure Variable provides fundamental operations for proper
  2609 treatment of fixed/schematic variables in a context.  For example,
  2610 Variable.import introduces fixes for schematics of given facts and
  2611 Variable.export reverses the effect (up to renaming) -- this replaces
  2612 various freeze_thaw operations.
  2613 
  2614 * Pure: structure Goal provides simple interfaces for
  2615 init/conclude/finish and tactical prove operations (replacing former
  2616 Tactic.prove).  Goal.prove is the canonical way to prove results
  2617 within a given context; Goal.prove_global is a degraded version for
  2618 theory level goals, including a global Drule.standard.  Note that
  2619 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2620 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2621 in a locale context).
  2622 
  2623 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2624 and type checking (Syntax.check_term etc.), with common combinations
  2625 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2626 which are considered legacy and await removal.
  2627 
  2628 * Pure/Syntax: generic interfaces for type unchecking
  2629 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2630 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2631 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2632 available for convenience, but refer to the very same operations using
  2633 a mere theory instead of a full context.
  2634 
  2635 * Isar: simplified treatment of user-level errors, using exception
  2636 ERROR of string uniformly.  Function error now merely raises ERROR,
  2637 without any side effect on output channels.  The Isar toplevel takes
  2638 care of proper display of ERROR exceptions.  ML code may use plain
  2639 handle/can/try; cat_error may be used to concatenate errors like this:
  2640 
  2641   ... handle ERROR msg => cat_error msg "..."
  2642 
  2643 Toplevel ML code (run directly or through the Isar toplevel) may be
  2644 embedded into the Isar toplevel with exception display/debug like
  2645 this:
  2646 
  2647   Isar.toplevel (fn () => ...)
  2648 
  2649 INCOMPATIBILITY, removed special transform_error facilities, removed
  2650 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2651 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2652 -- use plain ERROR instead.
  2653 
  2654 * Isar: theory setup now has type (theory -> theory), instead of a
  2655 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2656 
  2657 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2658 ProofContext.debug/verbose flags.
  2659 
  2660 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2661 theory before entering a proof state.  Transactions now always see a
  2662 quasi-functional intermediate checkpoint, both in interactive and
  2663 batch mode.
  2664 
  2665 * Isar: simplified interfaces for outer syntax.  Renamed
  2666 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2667 OuterSyntax.add_parsers -- this functionality is now included in
  2668 OuterSyntax.command etc.  INCOMPATIBILITY.
  2669 
  2670 * Simplifier: the simpset of a running simplification process now
  2671 contains a proof context (cf. Simplifier.the_context), which is the
  2672 very context that the initial simpset has been retrieved from (by
  2673 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2674 (solver, looper etc.) may depend on arbitrary proof data.
  2675 
  2676 * Simplifier.inherit_context inherits the proof context (plus the
  2677 local bounds) of the current simplification process; any simproc
  2678 etc. that calls the Simplifier recursively should do this!  Removed
  2679 former Simplifier.inherit_bounds, which is already included here --
  2680 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2681 specify an explicit context using Simplifier.context/theory_context.
  2682 
  2683 * Simplifier/Classical Reasoner: more abstract interfaces
  2684 change_simpset/claset for modifying the simpset/claset reference of a
  2685 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2686 INCOMPATIBILITY.
  2687 
  2688 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2689 "Trueprop" etc.
  2690 
  2691 
  2692 *** System ***
  2693 
  2694 * settings: the default heap location within ISABELLE_HOME_USER now
  2695 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2696 Isabelle installations.
  2697 
  2698 * isabelle-process: option -S (secure mode) disables some critical
  2699 operations, notably runtime compilation and evaluation of ML source
  2700 code.
  2701 
  2702 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2703 
  2704 * Support for parallel execution, using native multicore support of
  2705 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2706 independent theories, according to the given theory header
  2707 specifications. The maximum number of worker threads is specified via
  2708 usedir option -M or the "max-threads" setting in Proof General. A
  2709 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2710 to 6 on a 8-core machine.  User-code needs to observe certain
  2711 guidelines for thread-safe programming, see appendix A in the Isar
  2712 Implementation manual.
  2713 
  2714 
  2715 
  2716 New in Isabelle2005 (October 2005)
  2717 ----------------------------------
  2718 
  2719 *** General ***
  2720 
  2721 * Theory headers: the new header syntax for Isar theories is
  2722 
  2723   theory <name>
  2724   imports <theory1> ... <theoryN>
  2725   uses <file1> ... <fileM>
  2726   begin
  2727 
  2728 where the 'uses' part is optional.  The previous syntax
  2729 
  2730   theory <name> = <theory1> + ... + <theoryN>:
  2731 
  2732 will disappear in the next release.  Use isatool fixheaders to convert
  2733 existing theory files.  Note that there is no change in ancient
  2734 non-Isar theories now, but these will disappear soon.
  2735 
  2736 * Theory loader: parent theories can now also be referred to via
  2737 relative and absolute paths.
  2738 
  2739 * Command 'find_theorems' searches for a list of criteria instead of a
  2740 list of constants. Known criteria are: intro, elim, dest, name:string,
  2741 simp:term, and any term. Criteria can be preceded by '-' to select
  2742 theorems that do not match. Intro, elim, dest select theorems that
  2743 match the current goal, name:s selects theorems whose fully qualified
  2744 name contain s, and simp:term selects all simplification rules whose
  2745 lhs match term.  Any other term is interpreted as pattern and selects
  2746 all theorems matching the pattern. Available in ProofGeneral under
  2747 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2748 
  2749   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2750 
  2751 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2752 matching the current goal as introduction rule and not having "HOL."
  2753 in their name (i.e. not being defined in theory HOL).
  2754 
  2755 * Command 'thms_containing' has been discontinued in favour of
  2756 'find_theorems'; INCOMPATIBILITY.
  2757 
  2758 * Communication with Proof General is now 8bit clean, which means that
  2759 Unicode text in UTF-8 encoding may be used within theory texts (both
  2760 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2761 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2762 
  2763   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2764   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2765 
  2766 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2767 Classical Reasoner.  Typical big applications run around 2 times
  2768 faster.
  2769 
  2770 
  2771 *** Document preparation ***
  2772 
  2773 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2774 of raw sources.  Only those symbols that do not require additional
  2775 LaTeX packages (depending on comments in isabellesym.sty) are
  2776 displayed properly, everything else is left verbatim.  isatool display
  2777 and isatool print are used as front ends (these are subject to the
  2778 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2779 
  2780 * Command tags control specific markup of certain regions of text,
  2781 notably folding and hiding.  Predefined tags include "theory" (for
  2782 theory begin and end), "proof" for proof commands, and "ML" for
  2783 commands involving ML code; the additional tags "visible" and
  2784 "invisible" are unused by default.  Users may give explicit tag
  2785 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2786 interpretation of tags is determined by the LaTeX job during document
  2787 preparation: see option -V of isatool usedir, or options -n and -t of
  2788 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2789 \isadroptag.
  2790 
  2791 Several document versions may be produced at the same time via isatool
  2792 usedir (the generated index.html will link all of them).  Typical
  2793 specifications include ''-V document=theory,proof,ML'' to present
  2794 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2795 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2796 these parts without any formal replacement text.  The Isabelle site
  2797 default settings produce ''document'' and ''outline'' versions as
  2798 specified above.
  2799 
  2800 * Several new antiquotations:
  2801 
  2802   @{term_type term} prints a term with its type annotated;
  2803 
  2804   @{typeof term} prints the type of a term;
  2805 
  2806   @{const const} is the same as @{term const}, but checks that the
  2807   argument is a known logical constant;
  2808 
  2809   @{term_style style term} and @{thm_style style thm} print a term or
  2810   theorem applying a "style" to it
  2811 
  2812   @{ML text}
  2813 
  2814 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2815 definitions, equations, inequations etc., 'concl' printing only the
  2816 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2817 to print the specified premise.  TermStyle.add_style provides an ML
  2818 interface for introducing further styles.  See also the "LaTeX Sugar"
  2819 document practical applications.  The ML antiquotation prints
  2820 type-checked ML expressions verbatim.
  2821 
  2822 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2823 and 'text' support optional locale specification '(in loc)', which
  2824 specifies the default context for interpreting antiquotations.  For
  2825 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2826 
  2827 * Option 'locale=NAME' of antiquotations specifies an alternative
  2828 context interpreting the subsequent argument.  For example: @{thm
  2829 [locale=lattice] inf_assoc}.
  2830 
  2831 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2832 a proof context.
  2833 
  2834 * Proper output of antiquotations for theory commands involving a
  2835 proof context (such as 'locale' or 'theorem (in loc) ...').
  2836 
  2837 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2838 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2839 
  2840 * isatool usedir: new option -C (default true) controls whether option
  2841 -D should include a copy of the original document directory; -C false
  2842 prevents unwanted effects such as copying of administrative CVS data.
  2843 
  2844 
  2845 *** Pure ***
  2846 
  2847 * Considerably improved version of 'constdefs' command.  Now performs
  2848 automatic type-inference of declared constants; additional support for
  2849 local structure declarations (cf. locales and HOL records), see also
  2850 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2851 sequential dependencies of definitions within a single 'constdefs'
  2852 section; moreover, the declared name needs to be an identifier.  If
  2853 all fails, consider to fall back on 'consts' and 'defs' separately.
  2854 
  2855 * Improved indexed syntax and implicit structures.  First of all,
  2856 indexed syntax provides a notational device for subscripted
  2857 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2858 expressions.  Secondly, in a local context with structure
  2859 declarations, number indexes \<^sub>n or the empty index (default
  2860 number 1) refer to a certain fixed variable implicitly; option
  2861 show_structs controls printing of implicit structures.  Typical
  2862 applications of these concepts involve record types and locales.
  2863 
  2864 * New command 'no_syntax' removes grammar declarations (and
  2865 translations) resulting from the given syntax specification, which is
  2866 interpreted in the same manner as for the 'syntax' command.
  2867 
  2868 * 'Advanced' translation functions (parse_translation etc.) may depend
  2869 on the signature of the theory context being presently used for
  2870 parsing/printing, see also isar-ref manual.
  2871 
  2872 * Improved 'oracle' command provides a type-safe interface to turn an
  2873 ML expression of type theory -> T -> term into a primitive rule of
  2874 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2875 is already included here); see also FOL/ex/IffExample.thy;
  2876 INCOMPATIBILITY.
  2877 
  2878 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2879 before); "cI" is no longer bound, use "c.intro" instead.
  2880 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2881 axclasses vs. locales.
  2882 
  2883 * Improved internal renaming of symbolic identifiers -- attach primes
  2884 instead of base 26 numbers.
  2885 
  2886 * New flag show_question_marks controls printing of leading question
  2887 marks in schematic variable names.
  2888 
  2889 * In schematic variable names, *any* symbol following \<^isub> or
  2890 \<^isup> is now treated as part of the base name.  For example, the
  2891 following works without printing of awkward ".0" indexes:
  2892 
  2893   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2894     by simp
  2895 
  2896 * Inner syntax includes (*(*nested*) comments*).
  2897 
  2898 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2899 annotations as "(00...)".
  2900 
  2901 * Clear separation of logical types and nonterminals, where the latter
  2902 may only occur in 'syntax' specifications or type abbreviations.
  2903 Before that distinction was only partially implemented via type class
  2904 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2905 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2906 exotic syntax specifications may require further adaption
  2907 (e.g. Cube/Cube.thy).
  2908 
  2909 * Removed obsolete type class "logic", use the top sort {} instead.
  2910 Note that non-logical types should be declared as 'nonterminals'
  2911 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2912 specifications.
  2913 
  2914 * Attributes 'induct' and 'cases': type or set names may now be
  2915 locally fixed variables as well.
  2916 
  2917 * Simplifier: can now control the depth to which conditional rewriting
  2918 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2919 Limit.
  2920 
  2921 * Simplifier: simplification procedures may now take the current
  2922 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2923 interface), which is very useful for calling the Simplifier
  2924 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2925 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2926 low-level mk_simproc no longer applies Logic.varify internally, to
  2927 allow for use in a context of fixed variables.
  2928 
  2929 * thin_tac now works even if the assumption being deleted contains !!
  2930 or ==>.  More generally, erule now works even if the major premise of
  2931 the elimination rule contains !! or ==>.
  2932 
  2933 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2934 
  2935 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2936 from Pure, which contains all common declarations already.  Both
  2937 theories are defined via plain Isabelle/Isar .thy files.
  2938 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2939 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2940 use isatool fixcpure to adapt your theory and ML sources.
  2941 
  2942 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2943 selections of theorems in named facts via index ranges.
  2944 
  2945 * 'print_theorems': in theory mode, really print the difference
  2946 wrt. the last state (works for interactive theory development only),
  2947 in proof mode print all local facts (cf. 'print_facts');
  2948 
  2949 * 'hide': option '(open)' hides only base names.
  2950 
  2951 * More efficient treatment of intermediate checkpoints in interactive
  2952 theory development.
  2953 
  2954 * Code generator is now invoked via code_module (incremental code
  2955 generation) and code_library (modular code generation, ML structures
  2956 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2957 must be quoted when used as identifiers.
  2958 
  2959 * New 'value' command for reading, evaluating and printing terms using
  2960 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2961 quoted when used as identifier.
  2962 
  2963 
  2964 *** Locales ***
  2965 
  2966 * New commands for the interpretation of locale expressions in
  2967 theories (1), locales (2) and proof contexts (3).  These generate
  2968 proof obligations from the expression specification.  After the
  2969 obligations have been discharged, theorems of the expression are added
  2970 to the theory, target locale or proof context.  The synopsis of the
  2971 commands is a follows:
  2972 
  2973   (1) interpretation expr inst
  2974   (2) interpretation target < expr
  2975   (3) interpret expr inst
  2976 
  2977 Interpretation in theories and proof contexts require a parameter
  2978 instantiation of terms from the current context.  This is applied to
  2979 specifications and theorems of the interpreted expression.
  2980 Interpretation in locales only permits parameter renaming through the
  2981 locale expression.  Interpretation is smart in that interpretations
  2982 that are active already do not occur in proof obligations, neither are
  2983 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2984 inspect active interpretations of a particular locale.  For details,
  2985 see the Isar Reference manual.  Examples can be found in
  2986 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2987 
  2988 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2989 'interpret' instead.
  2990 
  2991 * New context element 'constrains' for adding type constraints to
  2992 parameters.
  2993 
  2994 * Context expressions: renaming of parameters with syntax
  2995 redeclaration.
  2996 
  2997 * Locale declaration: 'includes' disallowed.
  2998 
  2999 * Proper static binding of attribute syntax -- i.e. types / terms /
  3000 facts mentioned as arguments are always those of the locale definition
  3001 context, independently of the context of later invocations.  Moreover,
  3002 locale operations (renaming and type / term instantiation) are applied
  3003 to attribute arguments as expected.
  3004 
  3005 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  3006 actual attributes; rare situations may require Attrib.attribute to
  3007 embed those attributes into Attrib.src that lack concrete syntax.
  3008 Attribute implementations need to cooperate properly with the static
  3009 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  3010 Attrib.XXX_thm etc. already do the right thing without further
  3011 intervention.  Only unusual applications -- such as "where" or "of"
  3012 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  3013 on the context and the facts involved -- may have to assign parsed
  3014 values to argument tokens explicitly.
  3015 
  3016 * Changed parameter management in theorem generation for long goal
  3017 statements with 'includes'.  INCOMPATIBILITY: produces a different
  3018 theorem statement in rare situations.
  3019 
  3020 * Locale inspection command 'print_locale' omits notes elements.  Use
  3021 'print_locale!' to have them included in the output.
  3022 
  3023 
  3024 *** Provers ***
  3025 
  3026 * Provers/hypsubst.ML: improved version of the subst method, for
  3027 single-step rewriting: it now works in bound variable contexts. New is
  3028 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  3029 rewrite a different subterm than the original subst method, which is
  3030 still available as 'simplesubst'.
  3031 
  3032 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  3033 and quasi orders.
  3034 
  3035 * Provers/trancl.ML: new transitivity reasoner for transitive and
  3036 reflexive-transitive closure of relations.
  3037 
  3038 * Provers/blast.ML: new reference depth_limit to make blast's depth
  3039 limit (previously hard-coded with a value of 20) user-definable.
  3040 
  3041 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  3042 is peformed already.  Object-logics merely need to finish their
  3043 initial simpset configuration as before.  INCOMPATIBILITY.
  3044 
  3045 
  3046 *** HOL ***
  3047 
  3048 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3049 
  3050   syntax (epsilon)
  3051     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3052 
  3053 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3054 and x-symbol; use option '-m epsilon' to get it actually printed.
  3055 Moreover, the mathematically important symbolic identifier \<epsilon>
  3056 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3057 
  3058 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3059 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3060 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3061 support corresponding Isar calculations.
  3062 
  3063 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3064 instead of ":".
  3065 
  3066 * theory SetInterval: changed the syntax for open intervals:
  3067 
  3068   Old       New
  3069   {..n(}    {..<n}
  3070   {)n..}    {n<..}
  3071   {m..n(}   {m..<n}
  3072   {)m..n}   {m<..n}
  3073   {)m..n(}  {m<..<n}
  3074 
  3075 The old syntax is still supported but will disappear in the next
  3076 release.  For conversion use the following Emacs search and replace
  3077 patterns (these are not perfect but work quite well):
  3078 
  3079   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3080   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3081 
  3082 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3083 equalities in commutative rings; method 'algebra' provides a generic
  3084 interface.
  3085 
  3086 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3087 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3088 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3089 be a tuple pattern.
  3090 
  3091 Some new syntax forms are available:
  3092 
  3093   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3094   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3095   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3096   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3097 
  3098 The latter form "\<Sum>x < k. e" used to be based on a separate
  3099 function "Summation", which has been discontinued.
  3100 
  3101 * theory Finite_Set: in structured induction proofs, the insert case
  3102 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3103 (insert F x)'.
  3104 
  3105 * The 'refute' command has been extended to support a much larger
  3106 fragment of HOL, including axiomatic type classes, constdefs and
  3107 typedefs, inductive datatypes and recursion.
  3108 
  3109 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3110 Requires zChaff with proof generation to be installed.  See
  3111 HOL/ex/SAT_Examples.thy for examples.
  3112 
  3113 * Datatype induction via method 'induct' now preserves the name of the
  3114 induction variable. For example, when proving P(xs::'a list) by
  3115 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3116 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3117 in unstructured proof scripts.
  3118 
  3119 * Reworked implementation of records.  Improved scalability for
  3120 records with many fields, avoiding performance problems for type
  3121 inference. Records are no longer composed of nested field types, but
  3122 of nested extension types. Therefore the record type only grows linear
  3123 in the number of extensions and not in the number of fields.  The
  3124 top-level (users) view on records is preserved.  Potential
  3125 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3126 old record representation. The type generated for a record is called
  3127 <record_name>_ext_type.
  3128 
  3129 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3130 proofs triggered by a record definition or a simproc (if
  3131 quick_and_dirty is enabled).  Definitions of large records can take
  3132 quite long.
  3133 
  3134 New simproc record_upd_simproc for simplification of multiple record
  3135 updates enabled by default.  Moreover, trivial updates are also
  3136 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3137 occasionally, since simplification is more powerful by default.
  3138 
  3139 * typedef: proper support for polymorphic sets, which contain extra
  3140 type-variables in the term.
  3141 
  3142 * Simplifier: automatically reasons about transitivity chains
  3143 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3144 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3145 old proofs break occasionally as simplification may now solve more
  3146 goals than previously.
  3147 
  3148 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3149 present.  Works for all partial orders (class "order"), in particular
  3150 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3151 just like y <= x.
  3152 
  3153 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3154 bound variable or a constant then the let is unfolded.  Otherwise
  3155 first a is simplified to b, and then f b is simplified to g. If
  3156 possible we abstract b from g arriving at "let x = b in h x",
  3157 otherwise we unfold the let and arrive at g.  The simproc can be
  3158 enabled/disabled by the reference use_let_simproc.  Potential
  3159 INCOMPATIBILITY since simplification is more powerful by default.
  3160 
  3161 * Classical reasoning: the meson method now accepts theorems as arguments.
  3162 
  3163 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3164 jobs to provide advice on the provability of subgoals.
  3165 
  3166 * Theory OrderedGroup and Ring_and_Field: various additions and
  3167 improvements to faciliate calculations involving equalities and
  3168 inequalities.
  3169 
  3170 The following theorems have been eliminated or modified
  3171 (INCOMPATIBILITY):
  3172 
  3173   abs_eq             now named abs_of_nonneg
  3174   abs_of_ge_0        now named abs_of_nonneg
  3175   abs_minus_eq       now named abs_of_nonpos
  3176   imp_abs_id         now named abs_of_nonneg
  3177   imp_abs_neg_id     now named abs_of_nonpos
  3178   mult_pos           now named mult_pos_pos
  3179   mult_pos_le        now named mult_nonneg_nonneg
  3180   mult_pos_neg_le    now named mult_nonneg_nonpos
  3181   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3182   mult_neg           now named mult_neg_neg
  3183   mult_neg_le        now named mult_nonpos_nonpos
  3184 
  3185 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3186      
  3187      zero_le_square
  3188      not_square_less_zero 
  3189 
  3190   The following lemmas have been deleted from Real/RealPow:
  3191   
  3192      realpow_zero_zero
  3193      realpow_two
  3194      realpow_less
  3195      zero_le_power
  3196      realpow_two_le
  3197      abs_realpow_two
  3198      realpow_two_abs     
  3199 
  3200 * Theory Parity: added rules for simplifying exponents.
  3201 
  3202 * Theory List:
  3203 
  3204 The following theorems have been eliminated or modified
  3205 (INCOMPATIBILITY):
  3206 
  3207   list_all_Nil       now named list_all.simps(1)
  3208   list_all_Cons      now named list_all.simps(2)
  3209   list_all_conv      now named list_all_iff
  3210   set_mem_eq         now named mem_iff
  3211 
  3212 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3213 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3214 
  3215 
  3216 *** HOL-Complex ***
  3217 
  3218 * Theory RealDef: better support for embedding natural numbers and
  3219 integers in the reals.
  3220 
  3221 The following theorems have been eliminated or modified
  3222 (INCOMPATIBILITY):
  3223 
  3224   exp_ge_add_one_self  now requires no hypotheses
  3225   real_of_int_add      reversed direction of equality (use [symmetric])
  3226   real_of_int_minus    reversed direction of equality (use [symmetric])
  3227   real_of_int_diff     reversed direction of equality (use [symmetric])
  3228   real_of_int_mult     reversed direction of equality (use [symmetric])
  3229 
  3230 * Theory RComplete: expanded support for floor and ceiling functions.
  3231 
  3232 * Theory Ln is new, with properties of the natural logarithm
  3233 
  3234 * Hyperreal: There is a new type constructor "star" for making
  3235 nonstandard types.  The old type names are now type synonyms:
  3236 
  3237   hypreal = real star
  3238   hypnat = nat star
  3239   hcomplex = complex star
  3240 
  3241 * Hyperreal: Many groups of similarly-defined constants have been
  3242 replaced by polymorphic versions (INCOMPATIBILITY):
  3243 
  3244   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3245 
  3246   starset      <-- starsetNat, starsetC
  3247   *s*          <-- *sNat*, *sc*
  3248   starset_n    <-- starsetNat_n, starsetC_n
  3249   *sn*         <-- *sNatn*, *scn*
  3250   InternalSets <-- InternalNatSets, InternalCSets
  3251 
  3252   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3253   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3254   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3255   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3256   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3257 
  3258 * Hyperreal: Many type-specific theorems have been removed in favor of
  3259 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3260 
  3261   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3262   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3263   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3264   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3265   right_minus <-- hypreal_add_minus
  3266   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3267   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3268   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3269   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3270   mult_1_right <-- hcomplex_mult_one_right
  3271   mult_zero_left <-- hcomplex_mult_zero_left
  3272   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3273   right_distrib <-- hypnat_add_mult_distrib2
  3274   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3275   right_inverse <-- hypreal_mult_inverse
  3276   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3277   order_refl <-- {hypreal,hypnat}_le_refl
  3278   order_trans <-- {hypreal,hypnat}_le_trans
  3279   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3280   order_less_le <-- {hypreal,hypnat}_less_le
  3281   linorder_linear <-- {hypreal,hypnat}_le_linear
  3282   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3283   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3284   add_nonneg_nonneg <-- hypreal_le_add_order
  3285 
  3286 * Hyperreal: Separate theorems having to do with type-specific
  3287 versions of constants have been merged into theorems that apply to the
  3288 new polymorphic constants (INCOMPATIBILITY):
  3289 
  3290   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3291   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3292   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3293   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3294   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3295   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3296   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3297   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3298   STAR_diff <-- {STAR,STARC}_diff
  3299   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3300     STARC_hcomplex_of_complex}_image_subset
  3301   starset_n_Un <-- starset{Nat,C}_n_Un
  3302   starset_n_Int <-- starset{Nat,C}_n_Int
  3303   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3304   starset_n_diff <-- starset{Nat,C}_n_diff
  3305   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3306   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3307   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3308   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3309   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3310   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3311   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3312   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3313   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3314   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3315   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3316   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3317   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3318   starfun_diff <-- starfun{C,RC,CR}_diff
  3319   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3320   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3321   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3322   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3323   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3324   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3325   starfun_Id <-- starfunC_Id
  3326   starfun_approx <-- starfun{Nat,CR}_approx
  3327   starfun_capprox <-- starfun{C,RC}_capprox
  3328   starfun_abs <-- starfunNat_rabs
  3329   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3330   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3331   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3332   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3333   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3334   starfun_add_approx <-- starfunCR_add_approx
  3335   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3336   starfun_divide <-- starfun{C,CR,RC}_divide
  3337   starfun_n <-- starfun{Nat,C}_n
  3338   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3339   starfun_n_add <-- starfun{Nat,C}_n_add
  3340   starfun_n_add_minus <-- starfunNat_n_add_minus
  3341   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3342   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3343   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3344 
  3345   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3346   star_n_minus <-- {hypreal,hcomplex}_minus
  3347   star_n_diff <-- {hypreal,hcomplex}_diff
  3348   star_n_mult <-- {hypreal,hcomplex}_mult
  3349   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3350   star_n_le <-- {hypreal,hypnat}_le
  3351   star_n_less <-- {hypreal,hypnat}_less
  3352   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3353   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3354   star_n_abs <-- hypreal_hrabs
  3355   star_n_divide <-- hcomplex_divide
  3356 
  3357   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3358   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3359   star_of_diff <-- hypreal_of_real_diff
  3360   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3361   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3362   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3363   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3364   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3365   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3366   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3367   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3368   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3369   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3370   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3371   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3372   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3373   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3374   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3375   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3376   star_of_power <-- hypreal_of_real_power
  3377   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3378 
  3379 * Hyperreal: new method "transfer" that implements the transfer
  3380 principle of nonstandard analysis. With a subgoal that mentions
  3381 nonstandard types like "'a star", the command "apply transfer"
  3382 replaces it with an equivalent one that mentions only standard types.
  3383 To be successful, all free variables must have standard types; non-
  3384 standard variables must have explicit universal quantifiers.
  3385 
  3386 * Hyperreal: A theory of Taylor series.
  3387 
  3388 
  3389 *** HOLCF ***
  3390 
  3391 * Discontinued special version of 'constdefs' (which used to support
  3392 continuous functions) in favor of the general Pure one with full
  3393 type-inference.
  3394 
  3395 * New simplification procedure for solving continuity conditions; it
  3396 is much faster on terms with many nested lambda abstractions (cubic
  3397 instead of exponential time).
  3398 
  3399 * New syntax for domain package: selector names are now optional.
  3400 Parentheses should be omitted unless argument is lazy, for example:
  3401 
  3402   domain 'a stream = cons "'a" (lazy "'a stream")
  3403 
  3404 * New command 'fixrec' for defining recursive functions with pattern
  3405 matching; defining multiple functions with mutual recursion is also
  3406 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3407 sinr, or any data constructor defined by the domain package. The given
  3408 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3409 syntax and examples.
  3410 
  3411 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3412 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3413 but the proof obligation additionally includes an admissibility
  3414 requirement. The packages generate instances of class cpo or pcpo,
  3415 with continuity and strictness theorems for Rep and Abs.
  3416 
  3417 * HOLCF: Many theorems have been renamed according to a more standard naming
  3418 scheme (INCOMPATIBILITY):
  3419 
  3420   foo_inject:  "foo$x = foo$y ==> x = y"
  3421   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3422   foo_less:    "(foo$x << foo$y) = (x << y)"
  3423   foo_strict:  "foo$UU = UU"
  3424   foo_defined: "... ==> foo$x ~= UU"
  3425   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3426 
  3427 
  3428 *** ZF ***
  3429 
  3430 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3431 including the First Isomorphism Theorem (on quotienting by the kernel
  3432 of a homomorphism).
  3433 
  3434 * ZF/Simplifier: install second copy of type solver that actually
  3435 makes use of TC rules declared to Isar proof contexts (or locales);
  3436 the old version is still required for ML proof scripts.
  3437 
  3438 
  3439 *** Cube ***
  3440 
  3441 * Converted to Isar theory format; use locales instead of axiomatic
  3442 theories.
  3443 
  3444 
  3445 *** ML ***
  3446 
  3447 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3448 for ||>, ||>>, |>>,
  3449 
  3450 * Pure/library.ML no longer defines its own option datatype, but uses
  3451 that of the SML basis, which has constructors NONE and SOME instead of
  3452 None and Some, as well as exception Option.Option instead of OPTION.
  3453 The functions the, if_none, is_some, is_none have been adapted
  3454 accordingly, while Option.map replaces apsome.
  3455 
  3456 * Pure/library.ML: the exception LIST has been given up in favour of
  3457 the standard exceptions Empty and Subscript, as well as
  3458 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3459 superceded by the standard hd and tl functions etc.
  3460 
  3461 A number of basic list functions are no longer exported to the ML
  3462 toplevel, as they are variants of predefined functions.  The following
  3463 suggests how one can translate existing code:
  3464 
  3465     rev_append xs ys = List.revAppend (xs, ys)
  3466     nth_elem (i, xs) = List.nth (xs, i)
  3467     last_elem xs = List.last xs
  3468     flat xss = List.concat xss
  3469     seq fs = List.app fs
  3470     partition P xs = List.partition P xs
  3471     mapfilter f xs = List.mapPartial f xs
  3472 
  3473 * Pure/library.ML: several combinators for linear functional
  3474 transformations, notably reverse application and composition:
  3475 
  3476   x |> f                f #> g
  3477   (x, y) |-> f          f #-> g
  3478 
  3479 * Pure/library.ML: introduced/changed precedence of infix operators:
  3480 
  3481   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3482   infix 2 ?;
  3483   infix 3 o oo ooo oooo;
  3484   infix 4 ~~ upto downto;
  3485 
  3486 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3487 infix operators.
  3488 
  3489 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3490 fold_map support linear functional transformations and nesting.  For
  3491 example:
  3492 
  3493   fold f [x1, ..., xN] y =
  3494     y |> f x1 |> ... |> f xN
  3495 
  3496   (fold o fold) f [xs1, ..., xsN] y =
  3497     y |> fold f xs1 |> ... |> fold f xsN
  3498 
  3499   fold f [x1, ..., xN] =
  3500     f x1 #> ... #> f xN
  3501 
  3502   (fold o fold) f [xs1, ..., xsN] =
  3503     fold f xs1 #> ... #> fold f xsN
  3504 
  3505 * Pure/library.ML: the following selectors on type 'a option are
  3506 available:
  3507 
  3508   the:               'a option -> 'a  (*partial*)
  3509   these:             'a option -> 'a  where 'a = 'b list
  3510   the_default: 'a -> 'a option -> 'a
  3511   the_list:          'a option -> 'a list
  3512 
  3513 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3514 basic operations for association lists, following natural argument
  3515 order; moreover the explicit equality predicate passed here avoids
  3516 potentially expensive polymorphic runtime equality checks.
  3517 The old functions may be expressed as follows:
  3518 
  3519   assoc = uncurry (AList.lookup (op =))
  3520   assocs = these oo AList.lookup (op =)
  3521   overwrite = uncurry (AList.update (op =)) o swap
  3522 
  3523 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3524 
  3525   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3526   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3527 
  3528 replacing make_keylist and keyfilter (occassionally used)
  3529 Naive rewrites:
  3530 
  3531   make_keylist = AList.make
  3532   keyfilter = AList.find (op =)
  3533 
  3534 * eq_fst and eq_snd now take explicit equality parameter, thus
  3535   avoiding eqtypes. Naive rewrites:
  3536 
  3537     eq_fst = eq_fst (op =)
  3538     eq_snd = eq_snd (op =)
  3539 
  3540 * Removed deprecated apl and apr (rarely used).
  3541   Naive rewrites:
  3542 
  3543     apl (n, op) =>>= curry op n
  3544     apr (op, m) =>>= fn n => op (n, m)
  3545 
  3546 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3547 provides a reasonably efficient light-weight implementation of sets as
  3548 lists.
  3549 
  3550 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3551 few new operations; existing lookup and update are now curried to
  3552 follow natural argument order (for use with fold etc.);
  3553 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3554 
  3555 * Pure/General: output via the Isabelle channels of
  3556 writeln/warning/error etc. is now passed through Output.output, with a
  3557 hook for arbitrary transformations depending on the print_mode
  3558 (cf. Output.add_mode -- the first active mode that provides a output
  3559 function wins).  Already formatted output may be embedded into further
  3560 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3561 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3562 accommodate easy composition of diagnostic messages etc.  Programmers
  3563 rarely need to care about Output.output or Output.raw at all, with
  3564 some notable exceptions: Output.output is required when bypassing the
  3565 standard channels (writeln etc.), or in token translations to produce
  3566 properly formatted results; Output.raw is required when capturing
  3567 already output material that will eventually be presented to the user
  3568 a second time.  For the default print mode, both Output.output and
  3569 Output.raw have no effect.
  3570 
  3571 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3572 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3573 cumulative results are displayed at the end of a batch session.
  3574 
  3575 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3576 replaced by File.platform_path and File.shell_path (with appropriate
  3577 hooks).  This provides a clean interface for unusual systems where the
  3578 internal and external process view of file names are different.
  3579 
  3580 * Pure: more efficient orders for basic syntactic entities: added
  3581 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3582 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3583 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3584 orders now -- potential INCOMPATIBILITY for code that depends on a
  3585 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3586 Library.sort_strings on result).
  3587 
  3588 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3589 fold_types traverse types/terms from left to right, observing natural
  3590 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3591 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3592 
  3593 * Pure: name spaces have been refined, with significant changes of the
  3594 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3595 to extern(_table).  The plain name entry path is superceded by a
  3596 general 'naming' context, which also includes the 'policy' to produce
  3597 a fully qualified name and external accesses of a fully qualified
  3598 name; NameSpace.extend is superceded by context dependent
  3599 Sign.declare_name.  Several theory and proof context operations modify
  3600 the naming context.  Especially note Theory.restore_naming and
  3601 ProofContext.restore_naming to get back to a sane state; note that
  3602 Theory.add_path is no longer sufficient to recover from
  3603 Theory.absolute_path in particular.
  3604 
  3605 * Pure: new flags short_names (default false) and unique_names
  3606 (default true) for controlling output of qualified names.  If
  3607 short_names is set, names are printed unqualified.  If unique_names is
  3608 reset, the name prefix is reduced to the minimum required to achieve
  3609 the original result when interning again, even if there is an overlap
  3610 with earlier declarations.
  3611 
  3612 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3613 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3614 (useful for printing error messages).  INCOMPATIBILITY.
  3615 
  3616 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3617 Theory.theory are now identified, referring to the universal
  3618 Context.theory (see Pure/context.ML).  Actual signature and theory
  3619 content is managed as theory data.  The old code and interfaces were
  3620 spread over many files and structures; the new arrangement introduces
  3621 considerable INCOMPATIBILITY to gain more clarity:
  3622 
  3623   Context -- theory management operations (name, identity, inclusion,
  3624     parents, ancestors, merge, etc.), plus generic theory data;
  3625 
  3626   Sign -- logical signature and syntax operations (declaring consts,
  3627     types, etc.), plus certify/read for common entities;
  3628 
  3629   Theory -- logical theory operations (stating axioms, definitions,
  3630     oracles), plus a copy of logical signature operations (consts,
  3631     types, etc.); also a few basic management operations (Theory.copy,
  3632     Theory.merge, etc.)
  3633 
  3634 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3635 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3636 for convenience -- they merely return the theory.
  3637 
  3638 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3639 
  3640 * Pure: the Isar proof context type is already defined early in Pure
  3641 as Context.proof (note that ProofContext.context and Proof.context are
  3642 aliases, where the latter is the preferred name).  This enables other
  3643 Isabelle components to refer to that type even before Isar is present.
  3644 
  3645 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3646 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3647 any of these kinds.  For example, Sign.intern typeK is now
  3648 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3649 Theory.hide_types.  Also note that former
  3650 Theory.hide_classes/types/consts are now
  3651 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3652 internalize their arguments!  INCOMPATIBILITY.
  3653 
  3654 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3655 datatype thmref (with constructors Name and NameSelection) instead of
  3656 plain string -- INCOMPATIBILITY;
  3657 
  3658 * Pure: cases produced by proof methods specify options, where NONE
  3659 means to remove case bindings -- INCOMPATIBILITY in
  3660 (RAW_)METHOD_CASES.
  3661 
  3662 * Pure: the following operations retrieve axioms or theorems from a
  3663 theory node or theory hierarchy, respectively:
  3664 
  3665   Theory.axioms_of: theory -> (string * term) list
  3666   Theory.all_axioms_of: theory -> (string * term) list
  3667   PureThy.thms_of: theory -> (string * thm) list
  3668   PureThy.all_thms_of: theory -> (string * thm) list
  3669 
  3670 * Pure: print_tac now outputs the goal through the trace channel.
  3671 
  3672 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3673 Reference Toplevel.debug (default false) controls detailed printing
  3674 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3675 controls execution profiling -- set to 1 for time and 2 for space
  3676 (both increase the runtime).
  3677 
  3678 * Isar session: The initial use of ROOT.ML is now always timed,
  3679 i.e. the log will show the actual process times, in contrast to the
  3680 elapsed wall-clock time that the outer shell wrapper produces.
  3681 
  3682 * Simplifier: improved handling of bound variables (nameless
  3683 representation, avoid allocating new strings).  Simprocs that invoke
  3684 the Simplifier recursively should use Simplifier.inherit_bounds to
  3685 avoid local name clashes.  Failure to do so produces warnings
  3686 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3687 for further details.
  3688 
  3689 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3690 bindings for all theorems stored within a given theory; this may help
  3691 in porting non-Isar theories to Isar ones, while keeping ML proof
  3692 scripts for the time being.
  3693 
  3694 * ML operator HTML.with_charset specifies the charset begin used for
  3695 generated HTML files.  For example:
  3696 
  3697   HTML.with_charset "utf-8" use_thy "Hebrew";
  3698   HTML.with_charset "utf-8" use_thy "Chinese";
  3699 
  3700 
  3701 *** System ***
  3702 
  3703 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3704 isabelle, isatool etc.).
  3705 
  3706 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3707 isatool doc, isatool mkdir, display_drafts etc.).
  3708 
  3709 * isatool usedir: option -f allows specification of the ML file to be
  3710 used by Isabelle; default is ROOT.ML.
  3711 
  3712 * New isatool version outputs the version identifier of the Isabelle
  3713 distribution being used.
  3714 
  3715 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3716 (containing Boolean satisfiability problems) into Isabelle/HOL
  3717 theories.
  3718 
  3719 
  3720 
  3721 New in Isabelle2004 (April 2004)
  3722 --------------------------------
  3723 
  3724 *** General ***
  3725 
  3726 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3727   Replaces linorder.ML.
  3728 
  3729 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3730   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3731   (\<a>...\<z>), are now considered normal letters, and can therefore
  3732   be used anywhere where an ASCII letter (a...zA...Z) has until
  3733   now. COMPATIBILITY: This obviously changes the parsing of some
  3734   terms, especially where a symbol has been used as a binder, say
  3735   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3736   as an identifier.  Fix it by inserting a space around former
  3737   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3738   existing theory and ML files.
  3739 
  3740 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3741 
  3742 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3743   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3744   a normal (but invisible) letter. For multiple letter subscripts repeat
  3745   \<^isub> like this: x\<^isub>1\<^isub>2.
  3746 
  3747 * Pure: There are now sub-/superscripts that can span more than one
  3748   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3749   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3750   superscript. The new control characters are not identifier parts.
  3751 
  3752 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3753   content of "..." to the latex file instead of \isacntrl... . The "..."
  3754   may consist of any printable characters excluding the end bracket >.
  3755 
  3756 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3757   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3758   declare constants "final", which prevents their being given a definition
  3759   later.  It is useful for constants whose behaviour is fixed axiomatically
  3760   rather than definitionally, such as the meta-logic connectives.
  3761 
  3762 * Pure: 'instance' now handles general arities with general sorts
  3763   (i.e. intersections of classes),
  3764 
  3765 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3766   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3767   It can be changed to alter the colors/layout of generated pages.
  3768 
  3769 
  3770 *** Isar ***
  3771 
  3772 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3773   cut_tac, subgoal_tac and thin_tac:
  3774   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3775     locales are no longer forced to write Isar proof scripts.
  3776     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3777     emulations.
  3778   - INCOMPATIBILITY: names of variables to be instantiated may no
  3779     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3780     This is consistent with the instantiation attribute "where".
  3781 
  3782 * Attributes "where" and "of":
  3783   - Now take type variables of instantiated theorem into account when reading
  3784     the instantiation string.  This fixes a bug that caused instantiated
  3785     theorems to have too special types in some circumstances.
  3786   - "where" permits explicit instantiations of type variables.
  3787 
  3788 * Calculation commands "moreover" and "also" no longer interfere with
  3789   current facts ("this"), admitting arbitrary combinations with "then"
  3790   and derived forms.
  3791 
  3792 * Locales:
  3793   - Goal statements involving the context element "includes" no longer
  3794     generate theorems with internal delta predicates (those ending on
  3795     "_axioms") in the premise.
  3796     Resolve particular premise with <locale>.intro to obtain old form.
  3797   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3798     specification and "includes" elements in goal statement.
  3799   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3800     [intro?] and [elim?] (respectively) by default.
  3801   - Experimental command for instantiation of locales in proof contexts:
  3802         instantiate <label>[<attrs>]: <loc>
  3803     Instantiates locale <loc> and adds all its theorems to the current context
  3804     taking into account their attributes.  Label and attrs are optional
  3805     modifiers, like in theorem declarations.  If present, names of
  3806     instantiated theorems are qualified with <label>, and the attributes
  3807     <attrs> are applied after any attributes these theorems might have already.
  3808       If the locale has assumptions, a chained fact of the form
  3809     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3810     are derived.  The command does not support old-style locales declared
  3811     with "locale (open)".
  3812       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3813 
  3814 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3815   (Isar) contexts.
  3816 
  3817 
  3818 *** HOL ***
  3819 
  3820 * Proof import: new image HOL4 contains the imported library from
  3821   the HOL4 system with about 2500 theorems. It is imported by
  3822   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3823   can be used like any other Isabelle image.  See
  3824   HOL/Import/HOL/README for more information.
  3825 
  3826 * Simplifier:
  3827   - Much improved handling of linear and partial orders.
  3828     Reasoners for linear and partial orders are set up for type classes
  3829     "linorder" and "order" respectively, and are added to the default simpset
  3830     as solvers.  This means that the simplifier can build transitivity chains
  3831     to solve goals from the assumptions.
  3832   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3833     of blast or auto after simplification become unnecessary because the goal
  3834     is solved by simplification already.
  3835 
  3836 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3837     all proved in axiomatic type classes for semirings, rings and fields.
  3838 
  3839 * Numerics:
  3840   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3841     now formalized using the Ring_and_Field theory mentioned above.
  3842   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3843     than before, because now they are set up once in a generic manner.
  3844   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3845     Look for the general versions in Ring_and_Field (and Power if they concern
  3846     exponentiation).
  3847 
  3848 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3849 
  3850 * Records:
  3851   - Record types are now by default printed with their type abbreviation
  3852     instead of the list of all field types. This can be configured via
  3853     the reference "print_record_type_abbr".
  3854   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3855     (not enabled by default).
  3856   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3857     EX x. x = sel r to True (not enabled by default).
  3858   - Tactic "record_split_simp_tac" to split and simplify records added.
  3859 
  3860 * 'specification' command added, allowing for definition by
  3861   specification.  There is also an 'ax_specification' command that
  3862   introduces the new constants axiomatically.
  3863 
  3864 * arith(_tac) is now able to generate counterexamples for reals as well.
  3865 
  3866 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3867 
  3868 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3869   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3870 
  3871 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3872   matrix theory to linear programming.
  3873 
  3874 * Unions and Intersections:
  3875   The latex output syntax of UN and INT has been changed
  3876   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3877   i.e. the index formulae has become a subscript.
  3878   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3879 
  3880 * Unions and Intersections over Intervals:
  3881   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3882   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3883   like in normal math, and corresponding versions for < and for intersection.
  3884 
  3885 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3886   lexicographic dictonary ordering has been added as "lexord".
  3887 
  3888 * ML: the legacy theory structures Int and List have been removed. They had
  3889   conflicted with ML Basis Library structures having the same names.
  3890 
  3891 * 'refute' command added to search for (finite) countermodels.  Only works
  3892   for a fragment of HOL.  The installation of an external SAT solver is
  3893   highly recommended.  See "HOL/Refute.thy" for details.
  3894 
  3895 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3896   formulae under an assignment of free variables to random values.
  3897   In contrast to 'refute', it can deal with inductive datatypes,
  3898   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3899   for examples.
  3900 
  3901 
  3902 *** HOLCF ***
  3903 
  3904 * Streams now come with concatenation and are part of the HOLCF image
  3905 
  3906 
  3907 
  3908 New in Isabelle2003 (May 2003)
  3909 ------------------------------
  3910 
  3911 *** General ***
  3912 
  3913 * Provers/simplifier:
  3914 
  3915   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3916     Assumptions are now subject to complete mutual simplification,
  3917     not just from left to right. The simplifier now preserves
  3918     the order of assumptions.
  3919 
  3920     Potential INCOMPATIBILITY:
  3921 
  3922     -- simp sometimes diverges where the old version did
  3923        not, e.g. invoking simp on the goal
  3924 
  3925         [| P (f x); y = x; f x = f y |] ==> Q
  3926 
  3927        now gives rise to the infinite reduction sequence
  3928 
  3929         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3930 
  3931        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3932        kind of problem.
  3933 
  3934     -- Tactics combining classical reasoner and simplification (such as auto)
  3935        are also affected by this change, because many of them rely on
  3936        simp. They may sometimes diverge as well or yield a different numbers
  3937        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3938        in case of problems. Sometimes subsequent calls to the classical
  3939        reasoner will fail because a preceeding call to the simplifier too
  3940        eagerly simplified the goal, e.g. deleted redundant premises.
  3941 
  3942   - The simplifier trace now shows the names of the applied rewrite rules
  3943 
  3944   - You can limit the number of recursive invocations of the simplifier
  3945     during conditional rewriting (where the simplifie tries to solve the
  3946     conditions before applying the rewrite rule):
  3947     ML "simp_depth_limit := n"
  3948     where n is an integer. Thus you can force termination where previously
  3949     the simplifier would diverge.
  3950 
  3951   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3952 
  3953   - No longer aborts on failed congruence proof.  Instead, the
  3954     congruence is ignored.
  3955 
  3956 * Pure: New generic framework for extracting programs from constructive
  3957   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3958   as HOL/Extraction for some case studies.
  3959 
  3960 * Pure: The main goal of the proof state is no longer shown by default, only
  3961 the subgoals. This behaviour is controlled by a new flag.
  3962    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3963 (ML: Proof.show_main_goal).
  3964 
  3965 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3966 rules whose conclusion matches subgoal 1:
  3967       PG menu: Isabelle/Isar -> Show me -> matching rules
  3968 The rules are ordered by how closely they match the subgoal.
  3969 In particular, rules that solve a subgoal outright are displayed first
  3970 (or rather last, the way they are printed).
  3971 (ML: ProofGeneral.print_intros())
  3972 
  3973 * Pure: New flag trace_unify_fail causes unification to print
  3974 diagnostic information (PG: in trace buffer) when it fails. This is
  3975 useful for figuring out why single step proofs like rule, erule or
  3976 assumption failed.
  3977 
  3978 * Pure: Locale specifications now produce predicate definitions
  3979 according to the body of text (covering assumptions modulo local
  3980 definitions); predicate "loc_axioms" covers newly introduced text,
  3981 while "loc" is cumulative wrt. all included locale expressions; the
  3982 latter view is presented only on export into the global theory
  3983 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3984 on the old view without predicates;
  3985 
  3986 * Pure: predefined locales "var" and "struct" are useful for sharing
  3987 parameters (as in CASL, for example); just specify something like
  3988 ``var x + var y + struct M'' as import;
  3989 
  3990 * Pure: improved thms_containing: proper indexing of facts instead of
  3991 raw theorems; check validity of results wrt. current name space;
  3992 include local facts of proof configuration (also covers active
  3993 locales), cover fixed variables in index; may use "_" in term
  3994 specification; an optional limit for the number of printed facts may
  3995 be given (the default is 40);
  3996 
  3997 * Pure: disallow duplicate fact bindings within new-style theory files
  3998 (batch-mode only);
  3999 
  4000 * Provers: improved induct method: assumptions introduced by case
  4001 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  4002 the goal statement); "foo" still refers to all facts collectively;
  4003 
  4004 * Provers: the function blast.overloaded has been removed: all constants
  4005 are regarded as potentially overloaded, which improves robustness in exchange
  4006 for slight decrease in efficiency;
  4007 
  4008 * Provers/linorder: New generic prover for transitivity reasoning over
  4009 linear orders.  Note: this prover is not efficient!
  4010 
  4011 * Isar: preview of problems to finish 'show' now produce an error
  4012 rather than just a warning (in interactive mode);
  4013 
  4014 
  4015 *** HOL ***
  4016 
  4017 * arith(_tac)
  4018 
  4019  - Produces a counter example if it cannot prove a goal.
  4020    Note that the counter example may be spurious if the goal is not a formula
  4021    of quantifier-free linear arithmetic.
  4022    In ProofGeneral the counter example appears in the trace buffer.
  4023 
  4024  - Knows about div k and mod k where k is a numeral of type nat or int.
  4025 
  4026  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  4027    linear arithmetic fails. This takes account of quantifiers and divisibility.
  4028    Presburger arithmetic can also be called explicitly via presburger(_tac).
  4029 
  4030 * simp's arithmetic capabilities have been enhanced a bit: it now
  4031 takes ~= in premises into account (by performing a case split);
  4032 
  4033 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  4034 are distributed over a sum of terms;
  4035 
  4036 * New tactic "trans_tac" and method "trans" instantiate
  4037 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  4038 "<=", "<" and "=").
  4039 
  4040 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  4041 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  4042 
  4043 * 'typedef' command has new option "open" to suppress the set
  4044 definition;
  4045 
  4046 * functions Min and Max on finite sets have been introduced (theory
  4047 Finite_Set);
  4048 
  4049 * attribute [symmetric] now works for relations as well; it turns
  4050 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4051 
  4052 * induct over a !!-quantified statement (say !!x1..xn):
  4053   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4054 
  4055 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4056 %x. None. Warning: empty_def now refers to the previously hidden definition
  4057 of the empty set.
  4058 
  4059 * Algebra: formalization of classical algebra.  Intended as base for
  4060 any algebraic development in Isabelle.  Currently covers group theory
  4061 (up to Sylow's theorem) and ring theory (Universal Property of
  4062 Univariate Polynomials).  Contributions welcome;
  4063 
  4064 * GroupTheory: deleted, since its material has been moved to Algebra;
  4065 
  4066 * Complex: new directory of the complex numbers with numeric constants,
  4067 nonstandard complex numbers, and some complex analysis, standard and
  4068 nonstandard (Jacques Fleuriot);
  4069 
  4070 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4071 
  4072 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4073 Fleuriot);
  4074 
  4075 * Real/HahnBanach: updated and adapted to locales;
  4076 
  4077 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4078 Gray and Kramer);
  4079 
  4080 * UNITY: added the Meier-Sanders theory of progress sets;
  4081 
  4082 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4083 as abstract algorithms, instantiated to the JVM;
  4084 
  4085 * Bali: Java source language formalization. Type system, operational
  4086 semantics, axiomatic semantics. Supported language features:
  4087 classes, interfaces, objects,virtual methods, static methods,
  4088 static/instance fields, arrays, access modifiers, definite
  4089 assignment, exceptions.
  4090 
  4091 
  4092 *** ZF ***
  4093 
  4094 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4095 universe, etc.);
  4096 
  4097 * Main ZF: virtually all theories converted to new-style format;
  4098 
  4099 
  4100 *** ML ***
  4101 
  4102 * Pure: Tactic.prove provides sane interface for internal proofs;
  4103 omits the infamous "standard" operation, so this is more appropriate
  4104 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4105 
  4106 * Pure: improved error reporting of simprocs;
  4107 
  4108 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4109 up simprocs;
  4110 
  4111 
  4112 *** Document preparation ***
  4113 
  4114 * uses \par instead of \\ for line breaks in theory text. This may
  4115 shift some page breaks in large documents. To get the old behaviour
  4116 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4117 
  4118 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4119 other packages
  4120 
  4121 * \<euro> now needs package babel/greek instead of marvosym (which
  4122 broke \Rightarrow)
  4123 
  4124 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4125 textcomp package)
  4126 
  4127 
  4128 
  4129 New in Isabelle2002 (March 2002)
  4130 --------------------------------
  4131 
  4132 *** Document preparation ***
  4133 
  4134 * greatly simplified document preparation setup, including more
  4135 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4136 instructive isatool mkdir; users should basically be able to get
  4137 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4138 users may run a separate document processing stage manually like this:
  4139 "isatool usedir -D output HOL Test && isatool document Test/output";
  4140 
  4141 * theory dependency graph may now be incorporated into documents;
  4142 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4143 with \includegraphics of LaTeX;
  4144 
  4145 * proper spacing of consecutive markup elements, especially text
  4146 blocks after section headings;
  4147 
  4148 * support bold style (for single symbols only), input syntax is like
  4149 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4150 
  4151 * \<bullet> is now output as bold \cdot by default, which looks much
  4152 better in printed text;
  4153 
  4154 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4155 note that these symbols are currently unavailable in Proof General /
  4156 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4157 
  4158 * isatool latex no longer depends on changed TEXINPUTS, instead
  4159 isatool document copies the Isabelle style files to the target
  4160 location;
  4161 
  4162 
  4163 *** Isar ***
  4164 
  4165 * Pure/Provers: improved proof by cases and induction;
  4166   - 'case' command admits impromptu naming of parameters (such as
  4167     "case (Suc n)");
  4168   - 'induct' method divinates rule instantiation from the inductive
  4169     claim; no longer requires excessive ?P bindings for proper
  4170     instantiation of cases;
  4171   - 'induct' method properly enumerates all possibilities of set/type
  4172     rules; as a consequence facts may be also passed through *type*
  4173     rules without further ado;
  4174   - 'induct' method now derives symbolic cases from the *rulified*
  4175     rule (before it used to rulify cases stemming from the internal
  4176     atomized version); this means that the context of a non-atomic
  4177     statement becomes is included in the hypothesis, avoiding the
  4178     slightly cumbersome show "PROP ?case" form;
  4179   - 'induct' may now use elim-style induction rules without chaining
  4180     facts, using ``missing'' premises from the goal state; this allows
  4181     rules stemming from inductive sets to be applied in unstructured
  4182     scripts, while still benefitting from proper handling of non-atomic
  4183     statements; NB: major inductive premises need to be put first, all
  4184     the rest of the goal is passed through the induction;
  4185   - 'induct' proper support for mutual induction involving non-atomic
  4186     rule statements (uses the new concept of simultaneous goals, see
  4187     below);
  4188   - append all possible rule selections, but only use the first
  4189     success (no backtracking);
  4190   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4191   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4192   - added 'print_induct_rules' (covered by help item in recent Proof
  4193     General versions);
  4194   - moved induct/cases attributes to Pure, methods to Provers;
  4195   - generic method setup instantiated for FOL and HOL;
  4196 
  4197 * Pure: support multiple simultaneous goal statements, for example
  4198 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4199 meta-level mechanism, this acts as if several individual goals had
  4200 been stated separately; in particular common proof methods need to be
  4201 repeated in order to cover all claims; note that a single elimination
  4202 step is *not* sufficient to establish the two conjunctions, so this
  4203 fails:
  4204 
  4205   assume "A & B" then have A and B ..   (*".." fails*)
  4206 
  4207 better use "obtain" in situations as above; alternative refer to
  4208 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4209 
  4210 * Pure: proper integration with ``locales''; unlike the original
  4211 version by Florian Kammller, Isar locales package high-level proof
  4212 contexts rather than raw logical ones (e.g. we admit to include
  4213 attributes everywhere); operations on locales include merge and
  4214 rename; support for implicit arguments (``structures''); simultaneous
  4215 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4216 some examples;
  4217 
  4218 * Pure: the following commands have been ``localized'', supporting a
  4219 target locale specification "(in name)": 'lemma', 'theorem',
  4220 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4221 stored both within the locale and at the theory level (exported and
  4222 qualified by the locale name);
  4223 
  4224 * Pure: theory goals may now be specified in ``long'' form, with
  4225 ad-hoc contexts consisting of arbitrary locale elements. for example
  4226 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4227 definitions may be given, too); the result is a meta-level rule with
  4228 the context elements being discharged in the obvious way;
  4229 
  4230 * Pure: new proof command 'using' allows to augment currently used
  4231 facts after a goal statement ('using' is syntactically analogous to
  4232 'apply', but acts on the goal's facts only); this allows chained facts
  4233 to be separated into parts given before and after a claim, as in
  4234 ``from a and b have C using d and e <proof>'';
  4235 
  4236 * Pure: renamed "antecedent" case to "rule_context";
  4237 
  4238 * Pure: new 'judgment' command records explicit information about the
  4239 object-logic embedding (used by several tools internally); no longer
  4240 use hard-wired "Trueprop";
  4241 
  4242 * Pure: added 'corollary' command;
  4243 
  4244 * Pure: fixed 'token_translation' command;
  4245 
  4246 * Pure: removed obsolete 'exported' attribute;
  4247 
  4248 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4249 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4250 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4251 
  4252 * Pure: method 'atomize' presents local goal premises as object-level
  4253 statements (atomic meta-level propositions); setup controlled via
  4254 rewrite rules declarations of 'atomize' attribute; example
  4255 application: 'induct' method with proper rule statements in improper
  4256 proof *scripts*;
  4257 
  4258 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4259 now consider the syntactic context of assumptions, giving a better
  4260 chance to get type-inference of the arguments right (this is
  4261 especially important for locales);
  4262 
  4263 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4264 mode;
  4265 
  4266 * Pure/obtain: the formal conclusion "thesis", being marked as
  4267 ``internal'', may no longer be reference directly in the text;
  4268 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4269 situations;
  4270 
  4271 * Pure: generic 'sym' attribute which declares a rule both as pure
  4272 'elim?' and for the 'symmetric' operation;
  4273 
  4274 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4275 text; the fixed correlation with particular command syntax has been
  4276 discontinued;
  4277 
  4278 * Pure: new method 'rules' is particularly well-suited for proof
  4279 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4280 but often produces more compact proof terms with less detours;
  4281 
  4282 * Pure/Provers/classical: simplified integration with pure rule
  4283 attributes and methods; the classical "intro?/elim?/dest?"
  4284 declarations coincide with the pure ones; the "rule" method no longer
  4285 includes classically swapped intros; "intro" and "elim" methods no
  4286 longer pick rules from the context; also got rid of ML declarations
  4287 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4288 INCOMPATIBILITY;
  4289 
  4290 * Provers/classical: attribute 'swapped' produces classical inversions
  4291 of introduction rules;
  4292 
  4293 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4294 rules instead of full simplifier context; 'iff' attribute handles
  4295 conditional rules;
  4296 
  4297 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4298 
  4299 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4300 "(permissive)" option to recover old behavior;
  4301 
  4302 * HOL: 'inductive' no longer features separate (collective) attributes
  4303 for 'intros' (was found too confusing);
  4304 
  4305 * HOL: properly declared induction rules less_induct and
  4306 wf_induct_rule;
  4307 
  4308 
  4309 *** HOL ***
  4310 
  4311 * HOL: moved over to sane numeral syntax; the new policy is as
  4312 follows:
  4313 
  4314   - 0 and 1 are polymorphic constants, which are defined on any
  4315   numeric type (nat, int, real etc.);
  4316 
  4317   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4318   binary representation internally;
  4319 
  4320   - type nat has special constructor Suc, and generally prefers Suc 0
  4321   over 1::nat and Suc (Suc 0) over 2::nat;
  4322 
  4323 This change may cause significant problems of INCOMPATIBILITY; here
  4324 are some hints on converting existing sources:
  4325 
  4326   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4327   entities, so expressions involving "-" (unary or binary minus) need
  4328   to be spaced properly;
  4329 
  4330   - existing occurrences of "1" may need to be constraint "1::nat" or
  4331   even replaced by Suc 0; similar for old "2";
  4332 
  4333   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4334 
  4335   - remove all special provisions on numerals in proofs;
  4336 
  4337 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4338 representation (depends on bin_arith_simps in the default context);
  4339 
  4340 * HOL: symbolic syntax for x^2 (numeral 2);
  4341 
  4342 * HOL: the class of all HOL types is now called "type" rather than
  4343 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4344 in axclass/classes, instance/arities, and (usually rare) occurrences
  4345 in typings (of consts etc.); internally the class is called
  4346 "HOL.type", ML programs should refer to HOLogic.typeS;
  4347 
  4348 * HOL/record package improvements:
  4349   - new derived operations "fields" to build a partial record section,
  4350     "extend" to promote a fixed record to a record scheme, and
  4351     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4352     declared as simp by default;
  4353   - shared operations ("more", "fields", etc.) now need to be always
  4354     qualified) --- potential INCOMPATIBILITY;
  4355   - removed "make_scheme" operations (use "make" with "extend") --
  4356     INCOMPATIBILITY;
  4357   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4358   - provides cases/induct rules for use with corresponding Isar
  4359     methods (for concrete records, record schemes, concrete more
  4360     parts, and schematic more parts -- in that order);
  4361   - internal definitions directly based on a light-weight abstract
  4362     theory of product types over typedef rather than datatype;
  4363 
  4364 * HOL: generic code generator for generating executable ML code from
  4365 specifications; specific support for HOL constructs such as inductive
  4366 datatypes and sets, as well as recursive functions; can be invoked
  4367 via 'generate_code' theory section;
  4368 
  4369 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4370 
  4371 * HOL: consolidated and renamed several theories.  In particular:
  4372         Ord.thy has been absorbed into HOL.thy
  4373         String.thy has been absorbed into List.thy
  4374 
  4375 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4376 (beware of argument permutation!);
  4377 
  4378 * HOL: linorder_less_split superseded by linorder_cases;
  4379 
  4380 * HOL/List: "nodups" renamed to "distinct";
  4381 
  4382 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4383 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4384   - Ex_def has changed, now need to use some_eq_ex
  4385 
  4386 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4387 in this (rare) case use:
  4388 
  4389   delSWrapper "split_all_tac"
  4390   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4391 
  4392 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4393 MAY FAIL;
  4394 
  4395 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4396 Isabelle's type classes, ^ on functions and relations has too general
  4397 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4398 necessary to attach explicit type constraints;
  4399 
  4400 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4401 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4402 renamed accordingly (eg "compI" -> "rel_compI").
  4403 
  4404 * HOL: syntax translations now work properly with numerals and records
  4405 expressions;
  4406 
  4407 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4408 of "lam" -- INCOMPATIBILITY;
  4409 
  4410 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4411 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4412 renamed "Product_Type.unit";
  4413 
  4414 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4415 
  4416 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4417 the "cases" method);
  4418 
  4419 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4420 Florian Kammller);
  4421 
  4422 * HOL/IMP: updated and converted to new-style theory format; several
  4423 parts turned into readable document, with proper Isar proof texts and
  4424 some explanations (by Gerwin Klein);
  4425 
  4426 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4427 
  4428 * HOL-Hyperreal is now a logic image;
  4429 
  4430 
  4431 *** HOLCF ***
  4432 
  4433 * Isar: consts/constdefs supports mixfix syntax for continuous
  4434 operations;
  4435 
  4436 * Isar: domain package adapted to new-style theory format, e.g. see
  4437 HOLCF/ex/Dnat.thy;
  4438 
  4439 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4440 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4441 lift.induct_tac, always use UU instead of Undef;
  4442 
  4443 * HOLCF/IMP: updated and converted to new-style theory;
  4444 
  4445 
  4446 *** ZF ***
  4447 
  4448 * Isar: proper integration of logic-specific tools and packages,
  4449 including theory commands '(co)inductive', '(co)datatype',
  4450 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4451 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4452 
  4453 * theory Main no longer includes AC; for the Axiom of Choice, base
  4454 your theory on Main_ZFC;
  4455 
  4456 * the integer library now covers quotients and remainders, with many
  4457 laws relating division to addition, multiplication, etc.;
  4458 
  4459 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4460 typeless version of the formalism;
  4461 
  4462 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4463 format;
  4464 
  4465 * ZF/Induct: new directory for examples of inductive definitions,
  4466 including theory Multiset for multiset orderings; converted to
  4467 new-style theory format;
  4468 
  4469 * ZF: many new theorems about lists, ordinals, etc.;
  4470 
  4471 
  4472 *** General ***
  4473 
  4474 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4475 variable proof controls level of detail: 0 = no proofs (only oracle
  4476 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4477 also ref manual for further ML interfaces;
  4478 
  4479 * Pure/axclass: removed obsolete ML interface
  4480 goal_subclass/goal_arity;
  4481 
  4482 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4483 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4484 separate tokens, so expressions involving minus need to be spaced
  4485 properly;
  4486 
  4487 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4488 rather than "infixl" or "infixr";
  4489 
  4490 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4491 sort constraint specifications in type inference; e.g. "x::_::foo"
  4492 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4493 type variable);
  4494 
  4495 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4496 control output of nested => (types); the default behavior is
  4497 "type_brackets";
  4498 
  4499 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4500 tokens into AST constants;
  4501 
  4502 * Pure/syntax: prefer later declarations of translations and print
  4503 translation functions; potential INCOMPATIBILITY: need to reverse
  4504 multiple declarations for same syntax element constant;
  4505 
  4506 * Pure/show_hyps reset by default (in accordance to existing Isar
  4507 practice);
  4508 
  4509 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4510 addSafter;
  4511 
  4512 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4513 as well;
  4514 
  4515 * system: tested support for MacOS X; should be able to get Isabelle +
  4516 Proof General to work in a plain Terminal after installing Poly/ML
  4517 (e.g. from the Isabelle distribution area) and GNU bash alone
  4518 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4519 support requires further installations, e.g. from
  4520 http://fink.sourceforge.net/);
  4521 
  4522 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4523 
  4524 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4525 of 40 MB), cf. ML_OPTIONS;
  4526 
  4527 * system: Proof General keywords specification is now part of the
  4528 Isabelle distribution (see etc/isar-keywords.el);
  4529 
  4530 * system: support for persistent Proof General sessions (refrain from
  4531 outdating all loaded theories on startup); user may create writable
  4532 logic images like this: ``isabelle -q HOL Test'';
  4533 
  4534 * system: smart selection of Isabelle process versus Isabelle
  4535 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4536 run both "isabelle" and "Isabelle" even if file names are badly
  4537 damaged (executable inspects the case of the first letter of its own
  4538 name); added separate "isabelle-process" and "isabelle-interface";
  4539 
  4540 * system: refrain from any attempt at filtering input streams; no
  4541 longer support ``8bit'' encoding of old isabelle font, instead proper
  4542 iso-latin characters may now be used; the related isatools
  4543 "symbolinput" and "nonascii" have disappeared as well;
  4544 
  4545 * system: removed old "xterm" interface (the print modes "xterm" and
  4546 "xterm_color" are still available for direct use in a suitable
  4547 terminal);
  4548 
  4549 
  4550 
  4551 New in Isabelle99-2 (February 2001)
  4552 -----------------------------------
  4553 
  4554 *** Overview of INCOMPATIBILITIES ***
  4555 
  4556 * HOL: please note that theories in the Library and elsewhere often use the
  4557 new-style (Isar) format; to refer to their theorems in an ML script you must
  4558 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4559 
  4560 * HOL: inductive package no longer splits induction rule aggressively,
  4561 but only as far as specified by the introductions given; the old
  4562 format may be recovered via ML function complete_split_rule or attribute
  4563 'split_rule (complete)';
  4564 
  4565 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4566 gfp_Tarski to gfp_unfold;
  4567 
  4568 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4569 
  4570 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4571 relation); infix "^^" has been renamed "``"; infix "``" has been
  4572 renamed "`"; "univalent" has been renamed "single_valued";
  4573 
  4574 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4575 operation;
  4576 
  4577 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4578 
  4579 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4580 
  4581 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4582 consequence, it is no longer monotonic wrt. the local goal context
  4583 (which is now passed through the inductive cases);
  4584 
  4585 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4586 \<gg> to \<ggreater>;
  4587 
  4588 
  4589 *** Document preparation ***
  4590 
  4591 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4592 available: are "it" for near math-mode best-style output, "sl" for
  4593 slanted text style, and "tt" for plain type-writer; if no
  4594 \isabellestyle command is given, output is according to slanted
  4595 type-writer);
  4596 
  4597 * support sub/super scripts (for single symbols only), input syntax is
  4598 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4599 
  4600 * some more standard symbols; see Appendix A of the system manual for
  4601 the complete list of symbols defined in isabellesym.sty;
  4602 
  4603 * improved isabelle style files; more abstract symbol implementation
  4604 (should now use \isamath{...} and \isatext{...} in custom symbol
  4605 definitions);
  4606 
  4607 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4608 state; Note that presentation of goal states does not conform to
  4609 actual human-readable proof documents.  Please do not include goal
  4610 states into document output unless you really know what you are doing!
  4611 
  4612 * proper indentation of antiquoted output with proportional LaTeX
  4613 fonts;
  4614 
  4615 * no_document ML operator temporarily disables LaTeX document
  4616 generation;
  4617 
  4618 * isatool unsymbolize tunes sources for plain ASCII communication;
  4619 
  4620 
  4621 *** Isar ***
  4622 
  4623 * Pure: Isar now suffers initial goal statements to contain unbound
  4624 schematic variables (this does not conform to actual readable proof
  4625 documents, due to unpredictable outcome and non-compositional proof
  4626 checking); users who know what they are doing may use schematic goals
  4627 for Prolog-style synthesis of proven results;
  4628 
  4629 * Pure: assumption method (an implicit finishing) now handles actual
  4630 rules as well;
  4631 
  4632 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4633 initial goal, declare "that" only as Pure intro (only for single
  4634 steps); the "that" rule assumption may now be involved in implicit
  4635 finishing, thus ".." becomes a feasible for trivial obtains;
  4636 
  4637 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4638 instance proofs may be performed by "..";
  4639 
  4640 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4641 statements as well;
  4642 
  4643 * Pure: more robust selection of calculational rules;
  4644 
  4645 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4646 rule (as well as the assumption rule);
  4647 
  4648 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4649 lemmas, using the graph browser tool;
  4650 
  4651 * Pure: predict failure of "show" in interactive mode;
  4652 
  4653 * Pure: 'thms_containing' now takes actual terms as arguments;
  4654 
  4655 * HOL: improved method 'induct' --- now handles non-atomic goals
  4656 (potential INCOMPATIBILITY); tuned error handling;
  4657 
  4658 * HOL: cases and induct rules now provide explicit hints about the
  4659 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4660 any remaining facts are inserted into the goal verbatim;
  4661 
  4662 * HOL: local contexts (aka cases) may now contain term bindings as
  4663 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4664 the result to be shown in each case;
  4665 
  4666 * HOL: added 'recdef_tc' command;
  4667 
  4668 * isatool convert assists in eliminating legacy ML scripts;
  4669 
  4670 
  4671 *** HOL ***
  4672 
  4673 * HOL/Library: a collection of generic theories to be used together
  4674 with main HOL; the theory loader path already includes this directory
  4675 by default; the following existing theories have been moved here:
  4676 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4677 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4678 
  4679 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4680 modelling and verification task performed in Isabelle/HOL +
  4681 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4682 
  4683 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4684 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4685 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4686 'domain', this makes the theory consistent with mathematical
  4687 literature;
  4688 
  4689 * HOL basics: added overloaded operations "inverse" and "divide"
  4690 (infix "/"), syntax for generic "abs" operation, generic summation
  4691 operator \<Sum>;
  4692 
  4693 * HOL/typedef: simplified package, provide more useful rules (see also
  4694 HOL/subset.thy);
  4695 
  4696 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4697 now expressed as a proper nested rule (old-style tactic scripts may
  4698 require atomize_strip_tac to cope with non-atomic premises);
  4699 
  4700 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4701 to "split_conv" (old name still available for compatibility);
  4702 
  4703 * HOL: improved concrete syntax for strings (e.g. allows translation
  4704 rules with string literals);
  4705 
  4706 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4707  and Fleuriot's mechanization of analysis, including the transcendental
  4708  functions for the reals;
  4709 
  4710 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4711 
  4712 
  4713 *** CTT ***
  4714 
  4715 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4716 "lam" is displayed as TWO lambda-symbols
  4717 
  4718 * CTT: theory Main now available, containing everything (that is, Bool
  4719 and Arith);
  4720 
  4721 
  4722 *** General ***
  4723 
  4724 * Pure: the Simplifier has been implemented properly as a derived rule
  4725 outside of the actual kernel (at last!); the overall performance
  4726 penalty in practical applications is about 50%, while reliability of
  4727 the Isabelle inference kernel has been greatly improved;
  4728 
  4729 * print modes "brackets" and "no_brackets" control output of nested =>
  4730 (types) and ==> (props); the default behaviour is "brackets";
  4731 
  4732 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4733 as assumptions as well;
  4734 
  4735 * system: support Poly/ML 4.0;
  4736 
  4737 * system: isatool install handles KDE version 1 or 2;
  4738 
  4739 
  4740 
  4741 New in Isabelle99-1 (October 2000)
  4742 ----------------------------------
  4743 
  4744 *** Overview of INCOMPATIBILITIES ***
  4745 
  4746 * HOL: simplification of natural numbers is much changed; to partly
  4747 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4748 issue the following ML commands:
  4749 
  4750   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4751   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4752 
  4753 * HOL: simplification no longer dives into case-expressions; this is
  4754 controlled by "t.weak_case_cong" for each datatype t;
  4755 
  4756 * HOL: nat_less_induct renamed to less_induct;
  4757 
  4758 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4759 fixsome to patch .thy and .ML sources automatically;
  4760 
  4761   select_equality  -> some_equality
  4762   select_eq_Ex     -> some_eq_ex
  4763   selectI2EX       -> someI2_ex
  4764   selectI2         -> someI2
  4765   selectI          -> someI
  4766   select1_equality -> some1_equality
  4767   Eps_sym_eq       -> some_sym_eq_trivial
  4768   Eps_eq           -> some_eq_trivial
  4769 
  4770 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4771 
  4772 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4773 instead);
  4774 
  4775 * HOL: the recursion equations generated by 'recdef' are now called
  4776 f.simps instead of f.rules;
  4777 
  4778 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4779 
  4780 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4781 sometimes be needed;
  4782 
  4783 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4784 
  4785 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4786 
  4787 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4788 product is now "<*>" instead of "Times"; the lexicographic product is
  4789 now "<*lex*>" instead of "**";
  4790 
  4791 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4792 of main HOL, but was unused); better use HOL's datatype package;
  4793 
  4794 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4795 the old syntax may be recovered as follows:
  4796 
  4797   syntax (symbols)
  4798     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4799       (infixl "\\<oplus>" 100)
  4800 
  4801 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4802 
  4803 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4804 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4805 internally;
  4806 
  4807 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4808 changed from A/r to A//r;
  4809 
  4810 * ZF: new treatment of arithmetic (nat & int) may break some old
  4811 proofs;
  4812 
  4813 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4814 rulify -> rule_format, elimify -> elim_format, ...);
  4815 
  4816 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4817 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4818 should have to change intro!! to intro? only); replaced "delrule" by
  4819 "rule del";
  4820 
  4821 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4822 
  4823 * Provers: strengthened force_tac by using new first_best_tac;
  4824 
  4825 * LaTeX document preparation: several changes of isabelle.sty (see
  4826 lib/texinputs);
  4827 
  4828 
  4829 *** Document preparation ***
  4830 
  4831 * formal comments (text blocks etc.) in new-style theories may now
  4832 contain antiquotations of thm/prop/term/typ/text to be presented
  4833 according to latex print mode; concrete syntax is like this:
  4834 @{term[show_types] "f(x) = a + x"};
  4835 
  4836 * isatool mkdir provides easy setup of Isabelle session directories,
  4837 including proper document sources;
  4838 
  4839 * generated LaTeX sources are now deleted after successful run
  4840 (isatool document -c); may retain a copy somewhere else via -D option
  4841 of isatool usedir;
  4842 
  4843 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4844 style files, achieving self-contained LaTeX sources and simplifying
  4845 LaTeX debugging;
  4846 
  4847 * old-style theories now produce (crude) LaTeX output as well;
  4848 
  4849 * browser info session directories are now self-contained (may be put
  4850 on WWW server seperately); improved graphs of nested sessions; removed
  4851 graph for 'all sessions';
  4852 
  4853 * several improvements in isabelle style files; \isabellestyle{it}
  4854 produces fake math mode output; \isamarkupheader is now \section by
  4855 default; see lib/texinputs/isabelle.sty etc.;
  4856 
  4857 
  4858 *** Isar ***
  4859 
  4860 * Isar/Pure: local results and corresponding term bindings are now
  4861 subject to Hindley-Milner polymorphism (similar to ML); this
  4862 accommodates incremental type-inference very nicely;
  4863 
  4864 * Isar/Pure: new derived language element 'obtain' supports
  4865 generalized existence reasoning;
  4866 
  4867 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4868 support accumulation of results, without applying any rules yet;
  4869 useful to collect intermediate results without explicit name
  4870 references, and for use with transitivity rules with more than 2
  4871 premises;
  4872 
  4873 * Isar/Pure: scalable support for case-analysis type proofs: new
  4874 'case' language element refers to local contexts symbolically, as
  4875 produced by certain proof methods; internally, case names are attached
  4876 to theorems as "tags";
  4877 
  4878 * Isar/Pure: theory command 'hide' removes declarations from
  4879 class/type/const name spaces;
  4880 
  4881 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4882 indicate potential overloading;
  4883 
  4884 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4885 
  4886 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4887 "{a,b,c}" instead of {a,b,c};
  4888 
  4889 * Isar/Pure now provides its own version of intro/elim/dest
  4890 attributes; useful for building new logics, but beware of confusion
  4891 with the version in Provers/classical;
  4892 
  4893 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4894 case name 'antecedent';
  4895 
  4896 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4897 to the current context is now done automatically);
  4898 
  4899 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4900 for definining proof methods in ML;
  4901 
  4902 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4903 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4904 most cases, one should have to change intro!! to intro? only);
  4905 replaced "delrule" by "rule del";
  4906 
  4907 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4908 'symmetric' attribute (the latter supercedes [RS sym]);
  4909 
  4910 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4911 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4912 well (including splits);
  4913 
  4914 * Isar/Provers: Simplifier and Classical methods now support all kind
  4915 of modifiers used in the past, including 'cong', 'iff', etc.
  4916 
  4917 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4918 of Simplifier and Classical reasoner);
  4919 
  4920 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4921 now support named cases; major packages (inductive, datatype, primrec,
  4922 recdef) support case names and properly name parameters;
  4923 
  4924 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4925 monotonicity conditions are extracted to be proven at end of
  4926 calculations;
  4927 
  4928 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4929 method anyway;
  4930 
  4931 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4932 split_if split_if_asm; datatype package provides theorems foo.splits =
  4933 foo.split foo.split_asm for each datatype;
  4934 
  4935 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4936 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4937 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4938 use "(cases (simplified))" method in proper proof texts);
  4939 
  4940 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4941 
  4942 * Isar: names of theorems etc. may be natural numbers as well;
  4943 
  4944 * Isar: 'pr' command: optional arguments for goals_limit and
  4945 ProofContext.prems_limit; no longer prints theory contexts, but only
  4946 proof states;
  4947 
  4948 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4949 additional print modes to be specified; e.g. "pr(latex)" will print
  4950 proof state according to the Isabelle LaTeX style;
  4951 
  4952 * Isar: improved support for emulating tactic scripts, including proof
  4953 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4954 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4955 (for HOL datatypes);
  4956 
  4957 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4958 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4959 'proof method scripts' have to be in depth-first order;
  4960 
  4961 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4962 
  4963 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4964 should instead use individual commands for printing items
  4965 (print_commands, print_methods etc.);
  4966 
  4967 * Isar: added 'nothing' --- the empty list of theorems;
  4968 
  4969 
  4970 *** HOL ***
  4971 
  4972 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4973 corresponding virtual machine and a specification of its bytecode
  4974 verifier and a lightweight bytecode verifier, including proofs of
  4975 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4976 Cornelia Pusch (see also the homepage of project Bali at
  4977 http://isabelle.in.tum.de/Bali/);
  4978 
  4979 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4980 Clemens Ballarin;
  4981 
  4982 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4983 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4984 Rasmussen;
  4985 
  4986 * HOL/Lattice: fundamental concepts of lattice theory and order
  4987 structures, including duals, properties of bounds versus algebraic
  4988 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4989 Theorem for complete lattices etc.; may also serve as a demonstration
  4990 for abstract algebraic reasoning using axiomatic type classes, and
  4991 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4992 
  4993 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4994 von Oheimb;
  4995 
  4996 * HOL/IMPP: extension of IMP with local variables and mutually
  4997 recursive procedures, by David von Oheimb;
  4998 
  4999 * HOL/Lambda: converted into new-style theory and document;
  5000 
  5001 * HOL/ex/Multiquote: example of multiple nested quotations and
  5002 anti-quotations -- basically a generalized version of de-Bruijn
  5003 representation; very useful in avoiding lifting of operations;
  5004 
  5005 * HOL/record: added general record equality rule to simpset; fixed
  5006 select-update simplification procedure to handle extended records as
  5007 well; admit "r" as field name;
  5008 
  5009 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  5010 other numeric types and also as the identity of groups, rings, etc.;
  5011 
  5012 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  5013 Types nat and int belong to this axclass;
  5014 
  5015 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  5016    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  5017    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  5018   two terms #m*u and #n*u are replaced by #(m+n)*u
  5019     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  5020   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  5021     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  5022 
  5023 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  5024 powerful prover for predicate logic but knows nothing of clasets; see
  5025 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  5026 
  5027 * HOL: new version of "case_tac" subsumes both boolean case split and
  5028 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  5029 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  5030 
  5031 * HOL: simplification no longer dives into case-expressions: only the
  5032 selector expression is simplified, but not the remaining arms; to
  5033 enable full simplification of case-expressions for datatype t, you may
  5034 remove t.weak_case_cong from the simpset, either globally (Delcongs
  5035 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  5036 
  5037 * HOL/recdef: the recursion equations generated by 'recdef' for
  5038 function 'f' are now called f.simps instead of f.rules; if all
  5039 termination conditions are proved automatically, these simplification
  5040 rules are added to the simpset, as in primrec; rules may be named
  5041 individually as well, resulting in a separate list of theorems for
  5042 each equation;
  5043 
  5044 * HOL/While is a new theory that provides a while-combinator. It
  5045 permits the definition of tail-recursive functions without the
  5046 provision of a termination measure. The latter is necessary once the
  5047 invariant proof rule for while is applied.
  5048 
  5049 * HOL: new (overloaded) notation for the set of elements below/above
  5050 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5051 
  5052 * HOL: theorems impI, allI, ballI bound as "strip";
  5053 
  5054 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5055 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5056 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5057 
  5058 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5059 
  5060 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5061 main HOL, but was unused);
  5062 
  5063 * HOL: fewer consts declared as global (e.g. have to refer to
  5064 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5065 
  5066 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5067 in case of overlap with user translations (e.g. judgements over
  5068 tuples); (note that the underlying logical represenation is still
  5069 bogus);
  5070 
  5071 
  5072 *** ZF ***
  5073 
  5074 * ZF: simplification automatically cancels common terms in arithmetic
  5075 expressions over nat and int;
  5076 
  5077 * ZF: new treatment of nat to minimize type-checking: all operators
  5078 coerce their operands to a natural number using the function natify,
  5079 making the algebraic laws unconditional;
  5080 
  5081 * ZF: as above, for int: operators coerce their operands to an integer
  5082 using the function intify;
  5083 
  5084 * ZF: the integer library now contains many of the usual laws for the
  5085 orderings, including $<=, and monotonicity laws for $+ and $*;
  5086 
  5087 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5088 simplification;
  5089 
  5090 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5091 to the simplifier and classical reasoner simultaneously;
  5092 
  5093 
  5094 *** General ***
  5095 
  5096 * Provers: blast_tac now handles actual object-logic rules as
  5097 assumptions; note that auto_tac uses blast_tac internally as well;
  5098 
  5099 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5100 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5101 
  5102 * Provers: delrules now handles destruct rules as well (no longer need
  5103 explicit make_elim);
  5104 
  5105 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5106   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5107 use instead the strong form,
  5108   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5109 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5110 from destruct-rules;
  5111 
  5112 * Provers: Simplifier.easy_setup provides a fast path to basic
  5113 Simplifier setup for new object-logics;
  5114 
  5115 * Pure: AST translation rules no longer require constant head on LHS;
  5116 
  5117 * Pure: improved name spaces: ambiguous output is qualified; support
  5118 for hiding of names;
  5119 
  5120 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5121 XSYMBOL_HOME; no longer need to do manual configuration in most
  5122 situations;
  5123 
  5124 * system: compression of ML heaps images may now be controlled via -c
  5125 option of isabelle and isatool usedir (currently only observed by
  5126 Poly/ML);
  5127 
  5128 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5129 useful for remote X11);
  5130 
  5131 * system: provide TAGS file for Isabelle sources;
  5132 
  5133 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5134 order;
  5135 
  5136 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5137 timing flag supersedes proof_timing and Toplevel.trace;
  5138 
  5139 * ML: new combinators |>> and |>>> for incremental transformations
  5140 with secondary results (e.g. certain theory extensions):
  5141 
  5142 * ML: PureThy.add_defs gets additional argument to indicate potential
  5143 overloading (usually false);
  5144 
  5145 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5146 results;
  5147 
  5148 
  5149 
  5150 New in Isabelle99 (October 1999)
  5151 --------------------------------
  5152 
  5153 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5154 
  5155 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5156 are no longer simplified.  (This allows the simplifier to unfold recursive
  5157 functional programs.)  To restore the old behaviour, declare
  5158 
  5159     Delcongs [if_weak_cong];
  5160 
  5161 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5162 complement;
  5163 
  5164 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5165 
  5166 * HOL/datatype: mutual_induct_tac no longer exists --
  5167   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5168 
  5169 * HOL/typedef: fixed type inference for representing set; type
  5170 arguments now have to occur explicitly on the rhs as type constraints;
  5171 
  5172 * ZF: The con_defs part of an inductive definition may no longer refer
  5173 to constants declared in the same theory;
  5174 
  5175 * HOL, ZF: the function mk_cases, generated by the inductive
  5176 definition package, has lost an argument.  To simplify its result, it
  5177 uses the default simpset instead of a supplied list of theorems.
  5178 
  5179 * HOL/List: the constructors of type list are now Nil and Cons;
  5180 
  5181 * Simplifier: the type of the infix ML functions
  5182         setSSolver addSSolver setSolver addSolver
  5183 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5184 for packaging solvers. A solver is created via
  5185         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5186 where the string argument is only a comment.
  5187 
  5188 
  5189 *** Proof tools ***
  5190 
  5191 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5192 decision procedure for linear arithmetic. Currently it is used for
  5193 types `nat', `int', and `real' in HOL (see below); it can, should and
  5194 will be instantiated for other types and logics as well.
  5195 
  5196 * The simplifier now accepts rewrite rules with flexible heads, eg
  5197      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5198   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5199   matching.
  5200 
  5201 
  5202 *** General ***
  5203 
  5204 * New Isabelle/Isar subsystem provides an alternative to traditional
  5205 tactical theorem proving; together with the ProofGeneral/isar user
  5206 interface it offers an interactive environment for developing human
  5207 readable proof documents (Isar == Intelligible semi-automated
  5208 reasoning); for further information see isatool doc isar-ref,
  5209 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5210 
  5211 * improved and simplified presentation of theories: better HTML markup
  5212 (including colors), graph views in several sizes; isatool usedir now
  5213 provides a proper interface for user theories (via -P option); actual
  5214 document preparation based on (PDF)LaTeX is available as well (for
  5215 new-style theories only); see isatool doc system for more information;
  5216 
  5217 * native support for Proof General, both for classic Isabelle and
  5218 Isabelle/Isar;
  5219 
  5220 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5221 using the graph browser tool;
  5222 
  5223 * Isabelle manuals now also available as PDF;
  5224 
  5225 * theory loader rewritten from scratch (may not be fully
  5226 bug-compatible); old loadpath variable has been replaced by show_path,
  5227 add_path, del_path, reset_path functions; new operations such as
  5228 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5229 isatool doc ref);
  5230 
  5231 * improved isatool install: option -k creates KDE application icon,
  5232 option -p DIR installs standalone binaries;
  5233 
  5234 * added ML_PLATFORM setting (useful for cross-platform installations);
  5235 more robust handling of platform specific ML images for SML/NJ;
  5236 
  5237 * the settings environment is now statically scoped, i.e. it is never
  5238 created again in sub-processes invoked from isabelle, isatool, or
  5239 Isabelle;
  5240 
  5241 * path element specification '~~' refers to '$ISABELLE_HOME';
  5242 
  5243 * in locales, the "assumes" and "defines" parts may be omitted if
  5244 empty;
  5245 
  5246 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5247 long arrows);
  5248 
  5249 * new print_mode "HTML";
  5250 
  5251 * new flag show_tags controls display of tags of theorems (which are
  5252 basically just comments that may be attached by some tools);
  5253 
  5254 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5255 mode and goal output format:
  5256 
  5257 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5258 244c244
  5259 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5260 ---
  5261 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5262 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5263 181c181
  5264 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5265 ---
  5266 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5267 
  5268 * function bind_thms stores lists of theorems (cf. bind_thm);
  5269 
  5270 * new shorthand tactics ftac, eatac, datac, fatac;
  5271 
  5272 * qed (and friends) now accept "" as result name; in that case the
  5273 theorem is not stored, but proper checks and presentation of the
  5274 result still apply;
  5275 
  5276 * theorem database now also indexes constants "Trueprop", "all",
  5277 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5278 
  5279 
  5280 *** HOL ***
  5281 
  5282 ** HOL arithmetic **
  5283 
  5284 * There are now decision procedures for linear arithmetic over nat and
  5285 int:
  5286 
  5287 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5288 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5289 are treated as atomic; subformulae not involving type `nat' or `int'
  5290 are ignored; quantified subformulae are ignored unless they are
  5291 positive universal or negative existential. The tactic has to be
  5292 invoked by hand and can be a little bit slow. In particular, the
  5293 running time is exponential in the number of occurrences of `min' and
  5294 `max', and `-' on `nat'.
  5295 
  5296 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5297 (negated) (in)equalities among the premises and the conclusion into
  5298 account (i.e. no compound formulae) and does not know about `min' and
  5299 `max', and `-' on `nat'. It is fast and is used automatically by the
  5300 simplifier.
  5301 
  5302 NB: At the moment, these decision procedures do not cope with mixed
  5303 nat/int formulae where the two parts interact, such as `m < n ==>
  5304 int(m) < int(n)'.
  5305 
  5306 * HOL/Numeral provides a generic theory of numerals (encoded
  5307 efficiently as bit strings); setup for types nat/int/real is in place;
  5308 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5309 int, existing theories and proof scripts may require a few additional
  5310 type constraints;
  5311 
  5312 * integer division and remainder can now be performed on constant
  5313 arguments;
  5314 
  5315 * many properties of integer multiplication, division and remainder
  5316 are now available;
  5317 
  5318 * An interface to the Stanford Validity Checker (SVC) is available through the
  5319 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5320 are proved automatically.  SVC must be installed separately, and its results
  5321 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5322 invocation of the underlying oracle).  For SVC see
  5323   http://verify.stanford.edu/SVC
  5324 
  5325 * IsaMakefile: the HOL-Real target now builds an actual image;
  5326 
  5327 
  5328 ** HOL misc **
  5329 
  5330 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5331 (in Isabelle/Isar) -- by Gertrud Bauer;
  5332 
  5333 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5334 analysis for assembly languages with subtypes;
  5335 
  5336 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5337 -- avoids syntactic ambiguities and treats state, transition, and
  5338 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5339 changed syntax and (many) tactics;
  5340 
  5341 * HOL/inductive: Now also handles more general introduction rules such
  5342   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5343   theorems are now maintained within the theory (maintained via the
  5344   "mono" attribute);
  5345 
  5346 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5347   (using function types) such as
  5348 
  5349   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5350 
  5351 * HOL/record: record_simproc (part of the default simpset) takes care
  5352 of selectors applied to updated records; record_split_tac is no longer
  5353 part of the default claset; update_defs may now be removed from the
  5354 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5355 
  5356   claset_ref () := claset() addSWrapper record_split_wrapper;
  5357   Delsimprocs [record_simproc]
  5358 
  5359 * HOL/typedef: fixed type inference for representing set; type
  5360 arguments now have to occur explicitly on the rhs as type constraints;
  5361 
  5362 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5363 names rather than an ML expression;
  5364 
  5365 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5366 supplied later.  Program schemes can be defined, such as
  5367     "While B C s = (if B s then While B C (C s) else s)"
  5368 where the well-founded relation can be chosen after B and C have been given.
  5369 
  5370 * HOL/List: the constructors of type list are now Nil and Cons;
  5371 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5372 course, ML tools referring to List.list.op # etc. have to be adapted;
  5373 
  5374 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5375 disabled by default; run isabelle with option -m HOL to get back to
  5376 the original Gordon/HOL-style output;
  5377 
  5378 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5379 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5380 
  5381 * HOL basic syntax simplified (more orthogonal): all variants of
  5382 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5383 Eps operator is provided as well: "SOME x. P[x]";
  5384 
  5385 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5386 
  5387 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5388 thus available for user theories;
  5389 
  5390 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5391 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5392 time;
  5393 
  5394 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5395 several times and then mp;
  5396 
  5397 
  5398 *** LK ***
  5399 
  5400 * the notation <<...>> is now available as a notation for sequences of
  5401 formulas;
  5402 
  5403 * the simplifier is now installed
  5404 
  5405 * the axiom system has been generalized (thanks to Soren Heilmann)
  5406 
  5407 * the classical reasoner now has a default rule database
  5408 
  5409 
  5410 *** ZF ***
  5411 
  5412 * new primrec section allows primitive recursive functions to be given
  5413 directly (as in HOL) over datatypes and the natural numbers;
  5414 
  5415 * new tactics induct_tac and exhaust_tac for induction (or case
  5416 analysis) over datatypes and the natural numbers;
  5417 
  5418 * the datatype declaration of type T now defines the recursor T_rec;
  5419 
  5420 * simplification automatically does freeness reasoning for datatype
  5421 constructors;
  5422 
  5423 * automatic type-inference, with AddTCs command to insert new
  5424 type-checking rules;
  5425 
  5426 * datatype introduction rules are now added as Safe Introduction rules
  5427 to the claset;
  5428 
  5429 * the syntax "if P then x else y" is now available in addition to
  5430 if(P,x,y);
  5431 
  5432 
  5433 *** Internal programming interfaces ***
  5434 
  5435 * tuned simplifier trace output; new flag debug_simp;
  5436 
  5437 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5438 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5439 
  5440 * AxClass.axclass_tac lost the theory argument;
  5441 
  5442 * tuned current_goals_markers semantics: begin / end goal avoids
  5443 printing empty lines;
  5444 
  5445 * removed prs and prs_fn hook, which was broken because it did not
  5446 include \n in its semantics, forcing writeln to add one
  5447 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5448 string -> unit if you really want to output text without newline;
  5449 
  5450 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5451 plain output, interface builders may have to enable 'isabelle_font'
  5452 mode to get Isabelle font glyphs as before;
  5453 
  5454 * refined token_translation interface; INCOMPATIBILITY: output length
  5455 now of type real instead of int;
  5456 
  5457 * theory loader actions may be traced via new ThyInfo.add_hook
  5458 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5459 your own database of information attached to *whole* theories -- as
  5460 opposed to intra-theory data slots offered via TheoryDataFun;
  5461 
  5462 * proper handling of dangling sort hypotheses (at last!);
  5463 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5464 extra sort hypotheses that can be witnessed from the type signature;
  5465 the force_strip_shyps flag is gone, any remaining shyps are simply
  5466 left in the theorem (with a warning issued by strip_shyps_warning);
  5467 
  5468 
  5469 
  5470 New in Isabelle98-1 (October 1998)
  5471 ----------------------------------
  5472 
  5473 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5474 
  5475 * several changes of automated proof tools;
  5476 
  5477 * HOL: major changes to the inductive and datatype packages, including
  5478 some minor incompatibilities of theory syntax;
  5479 
  5480 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5481 called `inj_on';
  5482 
  5483 * HOL: removed duplicate thms in Arith:
  5484   less_imp_add_less  should be replaced by  trans_less_add1
  5485   le_imp_add_le      should be replaced by  trans_le_add1
  5486 
  5487 * HOL: unary minus is now overloaded (new type constraints may be
  5488 required);
  5489 
  5490 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5491 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5492 now taken as an integer constant.
  5493 
  5494 * Pure: ML function 'theory_of' renamed to 'theory';
  5495 
  5496 
  5497 *** Proof tools ***
  5498 
  5499 * Simplifier:
  5500   1. Asm_full_simp_tac is now more aggressive.
  5501      1. It will sometimes reorient premises if that increases their power to
  5502         simplify.
  5503      2. It does no longer proceed strictly from left to right but may also
  5504         rotate premises to achieve further simplification.
  5505      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5506      old Asm_full_simp_tac in that it does not rotate premises.
  5507   2. The simplifier now knows a little bit about nat-arithmetic.
  5508 
  5509 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5510 allows for selected deletion of wrappers, by introduction of names for
  5511 wrapper functionals.  This implies that addbefore, addSbefore,
  5512 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5513 and that adding two tactics with the same name overwrites the first
  5514 one (emitting a warning).
  5515   type wrapper = (int -> tactic) -> (int -> tactic)
  5516   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5517   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5518   delWrapper, delSWrapper: claset *  string            -> claset
  5519   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5520 
  5521 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5522 semantics; addbefore now affects only the unsafe part of step_tac
  5523 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5524 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5525 by Force_tac;
  5526 
  5527 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5528 compWrapper; added safe wrapper (and access functions for it);
  5529 
  5530 * HOL/split_all_tac is now much faster and fails if there is nothing
  5531 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5532 and the names of the automatically generated variables have changed.
  5533 split_all_tac has moved within claset() from unsafe wrappers to safe
  5534 wrappers, which means that !!-bound variables are split much more
  5535 aggressively, and safe_tac and clarify_tac now split such variables.
  5536 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5537 Note: the same holds for record_split_tac, which does the job of
  5538 split_all_tac for record fields.
  5539 
  5540 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5541 permanently to the default simpset using Addsplits just like
  5542 Addsimps. They can be removed via Delsplits just like
  5543 Delsimps. Lower-case versions are also available.
  5544 
  5545 * HOL/Simplifier: The rule split_if is now part of the default
  5546 simpset. This means that the simplifier will eliminate all occurrences
  5547 of if-then-else in the conclusion of a goal. To prevent this, you can
  5548 either remove split_if completely from the default simpset by
  5549 `Delsplits [split_if]' or remove it in a specific call of the
  5550 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5551 other case splitting rules to/from the default simpset: every datatype
  5552 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5553 t is the name of the datatype).
  5554 
  5555 * Classical reasoner / Simplifier combination: new force_tac (and
  5556 derivatives Force_tac, force) combines rewriting and classical
  5557 reasoning (and whatever other tools) similarly to auto_tac, but is
  5558 aimed to solve the given subgoal completely.
  5559 
  5560 
  5561 *** General ***
  5562 
  5563 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5564 and `goalw': the theory is no longer needed as an explicit argument -
  5565 the current theory context is used; assumptions are no longer returned
  5566 at the ML-level unless one of them starts with ==> or !!; it is
  5567 recommended to convert to these new commands using isatool fixgoal
  5568 (backup your sources first!);
  5569 
  5570 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5571 the current theory context, and 'theory' to lookup stored theories;
  5572 
  5573 * new theory section 'locale' for declaring constants, assumptions and
  5574 definitions that have local scope;
  5575 
  5576 * new theory section 'nonterminals' for purely syntactic types;
  5577 
  5578 * new theory section 'setup' for generic ML setup functions
  5579 (e.g. package initialization);
  5580 
  5581 * the distribution now includes Isabelle icons: see
  5582 lib/logo/isabelle-{small,tiny}.xpm;
  5583 
  5584 * isatool install - install binaries with absolute references to
  5585 ISABELLE_HOME/bin;
  5586 
  5587 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5588 
  5589 * print mode 'emacs' reserved for Isamode;
  5590 
  5591 * support multiple print (ast) translations per constant name;
  5592 
  5593 * theorems involving oracles are now printed with a suffixed [!];
  5594 
  5595 
  5596 *** HOL ***
  5597 
  5598 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5599 
  5600 * HOL/inductive package reorganized and improved: now supports mutual
  5601 definitions such as
  5602 
  5603   inductive EVEN ODD
  5604     intrs
  5605       null "0 : EVEN"
  5606       oddI "n : EVEN ==> Suc n : ODD"
  5607       evenI "n : ODD ==> Suc n : EVEN"
  5608 
  5609 new theorem list "elims" contains an elimination rule for each of the
  5610 recursive sets; inductive definitions now handle disjunctive premises
  5611 correctly (also ZF);
  5612 
  5613 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5614 "mutual_induct" no longer exists - the induction rule is always
  5615 contained in "induct";
  5616 
  5617 
  5618 * HOL/datatype package re-implemented and greatly improved: now
  5619 supports mutually recursive datatypes such as
  5620 
  5621   datatype
  5622     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5623             | SUM ('a aexp) ('a aexp)
  5624             | DIFF ('a aexp) ('a aexp)
  5625             | NUM 'a
  5626   and
  5627     'a bexp = LESS ('a aexp) ('a aexp)
  5628             | AND ('a bexp) ('a bexp)
  5629             | OR ('a bexp) ('a bexp)
  5630 
  5631 as well as indirectly recursive datatypes such as
  5632 
  5633   datatype
  5634     ('a, 'b) term = Var 'a
  5635                   | App 'b ((('a, 'b) term) list)
  5636 
  5637 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5638 induction on mutually / indirectly recursive datatypes.
  5639 
  5640 Primrec equations are now stored in theory and can be accessed via
  5641 <function_name>.simps.
  5642 
  5643 INCOMPATIBILITIES:
  5644 
  5645   - Theories using datatypes must now have theory Datatype as an
  5646     ancestor.
  5647   - The specific <typename>.induct_tac no longer exists - use the
  5648     generic induct_tac instead.
  5649   - natE has been renamed to nat.exhaust - use exhaust_tac
  5650     instead of res_inst_tac ... natE. Note that the variable
  5651     names in nat.exhaust differ from the names in natE, this
  5652     may cause some "fragile" proofs to fail.
  5653   - The theorems split_<typename>_case and split_<typename>_case_asm
  5654     have been renamed to <typename>.split and <typename>.split_asm.
  5655   - Since default sorts of type variables are now handled correctly,
  5656     some datatype definitions may have to be annotated with explicit
  5657     sort constraints.
  5658   - Primrec definitions no longer require function name and type
  5659     of recursive argument.
  5660 
  5661 Consider using isatool fixdatatype to adapt your theories and proof
  5662 scripts to the new package (backup your sources first!).
  5663 
  5664 
  5665 * HOL/record package: considerably improved implementation; now
  5666 includes concrete syntax for record types, terms, updates; theorems
  5667 for surjective pairing and splitting !!-bound record variables; proof
  5668 support is as follows:
  5669 
  5670   1) standard conversions (selectors or updates applied to record
  5671 constructor terms) are part of the standard simpset;
  5672 
  5673   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5674 made part of standard simpset and claset via addIffs;
  5675 
  5676   3) a tactic for record field splitting (record_split_tac) is part of
  5677 the standard claset (addSWrapper);
  5678 
  5679 To get a better idea about these rules you may retrieve them via
  5680 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5681 the name of your record type.
  5682 
  5683 The split tactic 3) conceptually simplifies by the following rule:
  5684 
  5685   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5686 
  5687 Thus any record variable that is bound by meta-all will automatically
  5688 blow up into some record constructor term, consequently the
  5689 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5690 solve record problems automatically.
  5691 
  5692 
  5693 * reorganized the main HOL image: HOL/Integ and String loaded by
  5694 default; theory Main includes everything;
  5695 
  5696 * automatic simplification of integer sums and comparisons, using cancellation;
  5697 
  5698 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5699 
  5700 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5701 
  5702 * many new identities for unions, intersections, set difference, etc.;
  5703 
  5704 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5705 called split_if, split_split, split_sum_case and split_nat_case (to go
  5706 with add/delsplits);
  5707 
  5708 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5709 (?x::unit) = (); this is made part of the default simpset, which COULD
  5710 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5711 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5712 unit_abs_eta_conv is added in order to counter the effect of
  5713 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5714 %u.f();
  5715 
  5716 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5717 makes more sense);
  5718 
  5719 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5720   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5721   disjointness reasoning but breaking a few old proofs.
  5722 
  5723 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5724 to 'converse' from 'inverse' (for compatibility with ZF and some
  5725 literature);
  5726 
  5727 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5728 the well-founded relation;
  5729 
  5730 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5731     Compl A.  The "Compl" syntax remains available as input syntax for this
  5732     release ONLY.
  5733 
  5734 * HOL/Update: new theory of function updates:
  5735     f(a:=b) == %x. if x=a then b else f x
  5736 may also be iterated as in f(a:=b,c:=d,...);
  5737 
  5738 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5739 
  5740 * HOL/List:
  5741   - new function list_update written xs[i:=v] that updates the i-th
  5742     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5743   - new function `upt' written [i..j(] which generates the list
  5744     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5745     bound write [i..j], which is a shorthand for [i..j+1(].
  5746   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5747 
  5748 * HOL/Arith:
  5749   - removed 'pred' (predecessor) function;
  5750   - generalized some theorems about n-1;
  5751   - many new laws about "div" and "mod";
  5752   - new laws about greatest common divisors (see theory ex/Primes);
  5753 
  5754 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5755 instead of "inverse";
  5756 
  5757 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5758   of the multiset ordering;
  5759 
  5760 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5761   (not included by default);
  5762 
  5763 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5764 
  5765 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5766   programs, i.e. different program variables may have different types.
  5767 
  5768 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5769   [previously, this check worked only if the rewrite rule was unconditional]
  5770   Now rew can involve either definitions or equalities (either == or =).
  5771 
  5772 
  5773 *** ZF ***
  5774 
  5775 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5776   only the theorems proved on ZF.ML;
  5777 
  5778 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5779   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5780   disjointness reasoning but breaking a few old proofs.
  5781 
  5782 * ZF/Update: new theory of function updates
  5783     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5784   may also be iterated as in f(a:=b,c:=d,...);
  5785 
  5786 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5787 
  5788 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5789   [previously, this check worked only if the rewrite rule was unconditional]
  5790   Now rew can involve either definitions or equalities (either == or =).
  5791 
  5792 * case_tac provided for compatibility with HOL
  5793     (like the old excluded_middle_tac, but with subgoals swapped)
  5794 
  5795 
  5796 *** Internal programming interfaces ***
  5797 
  5798 * Pure: several new basic modules made available for general use, see
  5799 also src/Pure/README;
  5800 
  5801 * improved the theory data mechanism to support encapsulation (data
  5802 kind name replaced by private Object.kind, acting as authorization
  5803 key); new type-safe user interface via functor TheoryDataFun; generic
  5804 print_data function becomes basically useless;
  5805 
  5806 * removed global_names compatibility flag -- all theory declarations
  5807 are qualified by default;
  5808 
  5809 * module Pure/Syntax now offers quote / antiquote translation
  5810 functions (useful for Hoare logic etc. with implicit dependencies);
  5811 see HOL/ex/Antiquote for an example use;
  5812 
  5813 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5814 cterm -> thm;
  5815 
  5816 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5817 subgoal;
  5818 
  5819 * Display.print_goals function moved to Locale.print_goals;
  5820 
  5821 * standard print function for goals supports current_goals_markers
  5822 variable for marking begin of proof, end of proof, start of goal; the
  5823 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5824 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5825 for example;
  5826 
  5827 
  5828 
  5829 New in Isabelle98 (January 1998)
  5830 --------------------------------
  5831 
  5832 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5833 
  5834 * changed lexical syntax of terms / types: dots made part of long
  5835 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5836 
  5837 * simpset (and claset) reference variable replaced by functions
  5838 simpset / simpset_ref;
  5839 
  5840 * no longer supports theory aliases (via merge) and non-trivial
  5841 implicit merge of thms' signatures;
  5842 
  5843 * most internal names of constants changed due to qualified names;
  5844 
  5845 * changed Pure/Sequence interface (see Pure/seq.ML);
  5846 
  5847 
  5848 *** General Changes ***
  5849 
  5850 * hierachically structured name spaces (for consts, types, axms, thms
  5851 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5852 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5853 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5854 long_names for fully qualified output names; NOTE: ML programs
  5855 (special tactics, packages etc.) referring to internal names may have
  5856 to be adapted to cope with fully qualified names; in case of severe
  5857 backward campatibility problems try setting 'global_names' at compile
  5858 time to have enrything declared within a flat name space; one may also
  5859 fine tune name declarations in theories via the 'global' and 'local'
  5860 section;
  5861 
  5862 * reimplemented the implicit simpset and claset using the new anytype
  5863 data filed in signatures; references simpset:simpset ref etc. are
  5864 replaced by functions simpset:unit->simpset and
  5865 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5866 to patch your ML files accordingly;
  5867 
  5868 * HTML output now includes theory graph data for display with Java
  5869 applet or isatool browser; data generated automatically via isatool
  5870 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5871 
  5872 * defs may now be conditional; improved rewrite_goals_tac to handle
  5873 conditional equations;
  5874 
  5875 * defs now admits additional type arguments, using TYPE('a) syntax;
  5876 
  5877 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5878 creates a new theory node; implicit merge of thms' signatures is
  5879 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5880 transfer:theory->thm->thm in (rare) cases;
  5881 
  5882 * improved handling of draft signatures / theories; draft thms (and
  5883 ctyps, cterms) are automatically promoted to real ones;
  5884 
  5885 * slightly changed interfaces for oracles: admit many per theory, named
  5886 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5887 
  5888 * print_goals: optional output of const types (set show_consts and
  5889 show_types);
  5890 
  5891 * improved output of warnings (###) and errors (***);
  5892 
  5893 * subgoal_tac displays a warning if the new subgoal has type variables;
  5894 
  5895 * removed old README and Makefiles;
  5896 
  5897 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5898 
  5899 * removed obsolete init_pps and init_database;
  5900 
  5901 * deleted the obsolete tactical STATE, which was declared by
  5902     fun STATE tacfun st = tacfun st st;
  5903 
  5904 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5905 (which abbreviates $HOME);
  5906 
  5907 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5908 use isatool fixseq to adapt your ML programs (this works for fully
  5909 qualified references to the Sequence structure only!);
  5910 
  5911 * use_thy no longer requires writable current directory; it always
  5912 reloads .ML *and* .thy file, if either one is out of date;
  5913 
  5914 
  5915 *** Classical Reasoner ***
  5916 
  5917 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5918 tactics that use classical reasoning to simplify a subgoal without
  5919 splitting it into several subgoals;
  5920 
  5921 * Safe_tac: like safe_tac but uses the default claset;
  5922 
  5923 
  5924 *** Simplifier ***
  5925 
  5926 * added simplification meta rules:
  5927     (asm_)(full_)simplify: simpset -> thm -> thm;
  5928 
  5929 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5930 logics (again);
  5931 
  5932 * added prems argument to simplification procedures;
  5933 
  5934 * HOL, FOL, ZF: added infix function `addsplits':
  5935   instead of `<simpset> setloop (split_tac <thms>)'
  5936   you can simply write `<simpset> addsplits <thms>'
  5937 
  5938 
  5939 *** Syntax ***
  5940 
  5941 * TYPE('a) syntax for type reflection terms;
  5942 
  5943 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5944 
  5945 * pretty printer: changed order of mixfix annotation preference (again!);
  5946 
  5947 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5948 
  5949 
  5950 *** HOL ***
  5951 
  5952 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5953   with `addloop' of the simplifier to faciliate case splitting in premises.
  5954 
  5955 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5956 
  5957 * HOL/Auth: new protocol proofs including some for the Internet
  5958   protocol TLS;
  5959 
  5960 * HOL/Map: new theory of `maps' a la VDM;
  5961 
  5962 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5963 cancelling out common nat summands from =, <, <= (in)equalities, or
  5964 differences; simplification procedures nat_cancel_factor for
  5965 cancelling common factor from =, <, <= (in)equalities over natural
  5966 sums; nat_cancel contains both kinds of procedures, it is installed by
  5967 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5968 
  5969 * HOL/simplifier: terms of the form
  5970   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5971   are rewritten to
  5972   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5973   and those of the form
  5974   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5975   are rewritten to
  5976   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5977 
  5978 * HOL/datatype
  5979   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5980 
  5981   P(t_case f1 ... fn x) =
  5982      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5983         ...
  5984        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5985      )
  5986 
  5987   and a theorem `split_t_case_asm' of the form
  5988 
  5989   P(t_case f1 ... fn x) =
  5990     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5991         ...
  5992        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5993      )
  5994   which can be added to a simpset via `addsplits'. The existing theorems
  5995   expand_list_case and expand_option_case have been renamed to
  5996   split_list_case and split_option_case.
  5997 
  5998 * HOL/Arithmetic:
  5999   - `pred n' is automatically converted to `n-1'.
  6000     Users are strongly encouraged not to use `pred' any longer,
  6001     because it will disappear altogether at some point.
  6002   - Users are strongly encouraged to write "0 < n" rather than
  6003     "n ~= 0". Theorems and proof tools have been modified towards this
  6004     `standard'.
  6005 
  6006 * HOL/Lists:
  6007   the function "set_of_list" has been renamed "set" (and its theorems too);
  6008   the function "nth" now takes its arguments in the reverse order and
  6009   has acquired the infix notation "!" as in "xs!n".
  6010 
  6011 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  6012 
  6013 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  6014   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  6015 
  6016 * HOL/record: extensible records with schematic structural subtyping
  6017 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  6018 still lacks various theorems and concrete record syntax;
  6019 
  6020 
  6021 *** HOLCF ***
  6022 
  6023 * removed "axioms" and "generated by" sections;
  6024 
  6025 * replaced "ops" section by extended "consts" section, which is capable of
  6026   handling the continuous function space "->" directly;
  6027 
  6028 * domain package:
  6029   . proves theorems immediately and stores them in the theory,
  6030   . creates hierachical name space,
  6031   . now uses normal mixfix annotations (instead of cinfix...),
  6032   . minor changes to some names and values (for consistency),
  6033   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  6034   . separator between mutual domain defs: changed "," to "and",
  6035   . improved handling of sort constraints;  now they have to
  6036     appear on the left-hand side of the equations only;
  6037 
  6038 * fixed LAM <x,y,zs>.b syntax;
  6039 
  6040 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  6041 adm (%x. P (t x)), where P is chainfinite and t continuous;
  6042 
  6043 
  6044 *** FOL and ZF ***
  6045 
  6046 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6047   with `addloop' of the simplifier to faciliate case splitting in premises.
  6048 
  6049 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6050 in HOL, they strip ALL and --> from proved theorems;
  6051 
  6052 
  6053 
  6054 New in Isabelle94-8 (May 1997)
  6055 ------------------------------
  6056 
  6057 *** General Changes ***
  6058 
  6059 * new utilities to build / run / maintain Isabelle etc. (in parts
  6060 still somewhat experimental); old Makefiles etc. still functional;
  6061 
  6062 * new 'Isabelle System Manual';
  6063 
  6064 * INSTALL text, together with ./configure and ./build scripts;
  6065 
  6066 * reimplemented type inference for greater efficiency, better error
  6067 messages and clean internal interface;
  6068 
  6069 * prlim command for dealing with lots of subgoals (an easier way of
  6070 setting goals_limit);
  6071 
  6072 
  6073 *** Syntax ***
  6074 
  6075 * supports alternative (named) syntax tables (parser and pretty
  6076 printer); internal interface is provided by add_modesyntax(_i);
  6077 
  6078 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6079 be used in conjunction with the Isabelle symbol font; uses the
  6080 "symbols" syntax table;
  6081 
  6082 * added token_translation interface (may translate name tokens in
  6083 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6084 the current print_mode); IMPORTANT: user print translation functions
  6085 are responsible for marking newly introduced bounds
  6086 (Syntax.mark_boundT);
  6087 
  6088 * token translations for modes "xterm" and "xterm_color" that display
  6089 names in bold, underline etc. or colors (which requires a color
  6090 version of xterm);
  6091 
  6092 * infixes may now be declared with names independent of their syntax;
  6093 
  6094 * added typed_print_translation (like print_translation, but may
  6095 access type of constant);
  6096 
  6097 
  6098 *** Classical Reasoner ***
  6099 
  6100 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6101 some limitations.  Blast_tac...
  6102   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6103   + ignores elimination rules that don't have the correct format
  6104         (the conclusion MUST be a formula variable)
  6105   + ignores types, which can make HOL proofs fail
  6106   + rules must not require higher-order unification, e.g. apply_type in ZF
  6107     [message "Function Var's argument not a bound variable" relates to this]
  6108   + its proof strategy is more general but can actually be slower
  6109 
  6110 * substitution with equality assumptions no longer permutes other
  6111 assumptions;
  6112 
  6113 * minor changes in semantics of addafter (now called addaltern); renamed
  6114 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6115 (and access functions for it);
  6116 
  6117 * improved combination of classical reasoner and simplifier:
  6118   + functions for handling clasimpsets
  6119   + improvement of addss: now the simplifier is called _after_ the
  6120     safe steps.
  6121   + safe variant of addss called addSss: uses safe simplifications
  6122     _during_ the safe steps. It is more complete as it allows multiple
  6123     instantiations of unknowns (e.g. with slow_tac).
  6124 
  6125 *** Simplifier ***
  6126 
  6127 * added interface for simplification procedures (functions that
  6128 produce *proven* rewrite rules on the fly, depending on current
  6129 redex);
  6130 
  6131 * ordering on terms as parameter (used for ordered rewriting);
  6132 
  6133 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6134 
  6135 * the solver is now split into a safe and an unsafe part.
  6136 This should be invisible for the normal user, except that the
  6137 functions setsolver and addsolver have been renamed to setSolver and
  6138 addSolver; added safe_asm_full_simp_tac;
  6139 
  6140 
  6141 *** HOL ***
  6142 
  6143 * a generic induction tactic `induct_tac' which works for all datatypes and
  6144 also for type `nat';
  6145 
  6146 * a generic case distinction tactic `exhaust_tac' which works for all
  6147 datatypes and also for type `nat';
  6148 
  6149 * each datatype comes with a function `size';
  6150 
  6151 * patterns in case expressions allow tuple patterns as arguments to
  6152 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6153 
  6154 * primrec now also works with type nat;
  6155 
  6156 * recdef: a new declaration form, allows general recursive functions to be
  6157 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6158 
  6159 * the constant for negation has been renamed from "not" to "Not" to
  6160 harmonize with FOL, ZF, LK, etc.;
  6161 
  6162 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6163 infinite lists;
  6164 
  6165 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6166 
  6167 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6168 problems in commutative rings, using axiomatic type classes for + and *;
  6169 
  6170 * more examples in HOL/MiniML and HOL/Auth;
  6171 
  6172 * more default rewrite rules for quantifiers, union/intersection;
  6173 
  6174 * a new constant `arbitrary == @x.False';
  6175 
  6176 * HOLCF/IOA replaces old HOL/IOA;
  6177 
  6178 * HOLCF changes: derived all rules and arities
  6179   + axiomatic type classes instead of classes
  6180   + typedef instead of faking type definitions
  6181   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6182   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6183   + eliminated the types void, one, tr
  6184   + use unit lift and bool lift (with translations) instead of one and tr
  6185   + eliminated blift from Lift3.thy (use Def instead of blift)
  6186   all eliminated rules are derived as theorems --> no visible changes ;
  6187 
  6188 
  6189 *** ZF ***
  6190 
  6191 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6192 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6193 as ZF_cs addSIs [equalityI];
  6194 
  6195 
  6196 
  6197 New in Isabelle94-7 (November 96)
  6198 ---------------------------------
  6199 
  6200 * allowing negative levels (as offsets) in prlev and choplev;
  6201 
  6202 * super-linear speedup for large simplifications;
  6203 
  6204 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6205 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6206 FAIL); can suppress it using the command Delsimps (ex_simps @
  6207 all_simps); De Morgan laws are also now included, by default;
  6208 
  6209 * improved printing of ==>  :  ~:
  6210 
  6211 * new object-logic "Sequents" adds linear logic, while replacing LK
  6212 and Modal (thanks to Sara Kalvala);
  6213 
  6214 * HOL/Auth: correctness proofs for authentication protocols;
  6215 
  6216 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6217 examples on HOL/Auth);
  6218 
  6219 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6220 the rewriter and classical reasoner simultaneously;
  6221 
  6222 * function uresult no longer returns theorems in "standard" format;
  6223 regain previous version by: val uresult = standard o uresult;
  6224 
  6225 
  6226 
  6227 New in Isabelle94-6
  6228 -------------------
  6229 
  6230 * oracles -- these establish an interface between Isabelle and trusted
  6231 external reasoners, which may deliver results as theorems;
  6232 
  6233 * proof objects (in particular record all uses of oracles);
  6234 
  6235 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6236 
  6237 * "constdefs" section in theory files;
  6238 
  6239 * "primrec" section (HOL) no longer requires names;
  6240 
  6241 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6242 
  6243 
  6244 
  6245 New in Isabelle94-5
  6246 -------------------
  6247 
  6248 * reduced space requirements;
  6249 
  6250 * automatic HTML generation from theories;
  6251 
  6252 * theory files no longer require "..." (quotes) around most types;
  6253 
  6254 * new examples, including two proofs of the Church-Rosser theorem;
  6255 
  6256 * non-curried (1994) version of HOL is no longer distributed;
  6257 
  6258 
  6259 
  6260 New in Isabelle94-4
  6261 -------------------
  6262