NEWS
author wenzelm
Sun May 31 14:15:07 2009 +0200 (2009-05-31)
changeset 31308 3fd52453ae81
parent 31306 a74ee84288a0
child 31317 1f5740424c69
permissions -rw-r--r--
discontinued support for Poly/ML 4.x versions;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** Pure ***
     8 
     9 * On instantiation of classes, remaining undefined class parameters are
    10 formally declared.  INCOMPATIBILITY.
    11 
    12 
    13 *** HOL ***
    14 
    15 * Class semiring_div requires superclass no_zero_divisors and proof of div_mult_mult1;
    16 theorems div_mult_mult1, div_mult_mult2, div_mult_mult1_if, div_mult_mult1 and
    17 div_mult_mult2 have been generalized to class semiring_div, subsuming former
    18 theorems zdiv_zmult_zmult1, zdiv_zmult_zmult1_if, zdiv_zmult_zmult1 and zdiv_zmult_zmult2.
    19 div_mult_mult1 is now [simp] by default.  INCOMPATIBILITY.
    20 
    21 * Power operations on relations and functions are now one dedicate constant compow with
    22 infix syntax "^^".  Power operations on multiplicative monoids retains syntax "^"
    23 and is now defined generic in class power.  INCOMPATIBILITY.
    24 
    25 * ML antiquotation @{code_datatype} inserts definition of a datatype generated
    26 by the code generator; see Predicate.thy for an example.
    27 
    28 
    29 *** ML ***
    30 
    31 * Eliminated old Attrib.add_attributes, Method.add_methods and related
    32 cominators for "args".  INCOMPATIBILITY, need to use simplified
    33 Attrib/Method.setup introduced in Isabelle2009.
    34 
    35 
    36 *** System ***
    37 
    38 * Discontinued support for Poly/ML 4.x versions.
    39 
    40 
    41 
    42 New in Isabelle2009 (April 2009)
    43 --------------------------------
    44 
    45 *** General ***
    46 
    47 * Simplified main Isabelle executables, with less surprises on
    48 case-insensitive file-systems (such as Mac OS).
    49 
    50   - The main Isabelle tool wrapper is now called "isabelle" instead of
    51     "isatool."
    52 
    53   - The former "isabelle" alias for "isabelle-process" has been
    54     removed (should rarely occur to regular users).
    55 
    56   - The former "isabelle-interface" and its alias "Isabelle" have been
    57     removed (interfaces are now regular Isabelle tools).
    58 
    59 Within scripts and make files, the Isabelle environment variables
    60 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    61 respectively.  (The latter are still available as legacy feature.)
    62 
    63 The old isabelle-interface wrapper could react in confusing ways if
    64 the interface was uninstalled or changed otherwise.  Individual
    65 interface tool configuration is now more explicit, see also the
    66 Isabelle system manual.  In particular, Proof General is now available
    67 via "isabelle emacs".
    68 
    69 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    70 purge installed copies of Isabelle executables and re-run "isabelle
    71 install -p ...", or use symlinks.
    72 
    73 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    74 old ~/isabelle, which was slightly non-standard and apt to cause
    75 surprises on case-insensitive file-systems (such as Mac OS).
    76 
    77 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    78 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    79 care is required when using older releases of Isabelle.  Note that
    80 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    81 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
    82 
    83 * Proofs of fully specified statements are run in parallel on
    84 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
    85 a regular 4-core machine, if the initial heap space is made reasonably
    86 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
    87 
    88 * The main reference manuals ("isar-ref", "implementation", and
    89 "system") have been updated and extended.  Formally checked references
    90 as hyperlinks are now available uniformly.
    91 
    92 
    93 *** Pure ***
    94 
    95 * Complete re-implementation of locales.  INCOMPATIBILITY in several
    96 respects.  The most important changes are listed below.  See the
    97 Tutorial on Locales ("locales" manual) for details.
    98 
    99 - In locale expressions, instantiation replaces renaming.  Parameters
   100 must be declared in a for clause.  To aid compatibility with previous
   101 parameter inheritance, in locale declarations, parameters that are not
   102 'touched' (instantiation position "_" or omitted) are implicitly added
   103 with their syntax at the beginning of the for clause.
   104 
   105 - Syntax from abbreviations and definitions in locales is available in
   106 locale expressions and context elements.  The latter is particularly
   107 useful in locale declarations.
   108 
   109 - More flexible mechanisms to qualify names generated by locale
   110 expressions.  Qualifiers (prefixes) may be specified in locale
   111 expressions, and can be marked as mandatory (syntax: "name!:") or
   112 optional (syntax "name?:").  The default depends for plain "name:"
   113 depends on the situation where a locale expression is used: in
   114 commands 'locale' and 'sublocale' prefixes are optional, in
   115 'interpretation' and 'interpret' prefixes are mandatory.  The old
   116 implicit qualifiers derived from the parameter names of a locale are
   117 no longer generated.
   118 
   119 - Command "sublocale l < e" replaces "interpretation l < e".  The
   120 instantiation clause in "interpretation" and "interpret" (square
   121 brackets) is no longer available.  Use locale expressions.
   122 
   123 - When converting proof scripts, mandatory qualifiers in
   124 'interpretation' and 'interpret' should be retained by default, even
   125 if this is an INCOMPATIBILITY compared to former behavior.  In the
   126 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   127 in locale expressions range over a single locale instance only.
   128 
   129 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   130 In existing theorem specifications replace the includes element by the
   131 respective context elements of the included locale, omitting those
   132 that are already present in the theorem specification.  Multiple
   133 assume elements of a locale should be replaced by a single one
   134 involving the locale predicate.  In the proof body, declarations (most
   135 notably theorems) may be regained by interpreting the respective
   136 locales in the proof context as required (command "interpret").
   137 
   138 If using "includes" in replacement of a target solely because the
   139 parameter types in the theorem are not as general as in the target,
   140 consider declaring a new locale with additional type constraints on
   141 the parameters (context element "constrains").
   142 
   143 - Discontinued "locale (open)".  INCOMPATIBILITY.
   144 
   145 - Locale interpretation commands no longer attempt to simplify goal.
   146 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   147 methods intro_locales and unfold_locales to clarify.
   148 
   149 - Locale interpretation commands no longer accept interpretation
   150 attributes.  INCOMPATIBILITY.
   151 
   152 * Class declaration: so-called "base sort" must not be given in import
   153 list any longer, but is inferred from the specification.  Particularly
   154 in HOL, write
   155 
   156     class foo = ...
   157 
   158 instead of
   159 
   160     class foo = type + ...
   161 
   162 * Class target: global versions of theorems stemming do not carry a
   163 parameter prefix any longer.  INCOMPATIBILITY.
   164 
   165 * Class 'instance' command no longer accepts attached definitions.
   166 INCOMPATIBILITY, use proper 'instantiation' target instead.
   167 
   168 * Recovered hiding of consts, which was accidentally broken in
   169 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   170 makes c inaccessible; consider using ``hide (open) const c'' instead.
   171 
   172 * Slightly more coherent Pure syntax, with updated documentation in
   173 isar-ref manual.  Removed locales meta_term_syntax and
   174 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   175 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   176 directly in regular applications.
   177 
   178 * There is a new syntactic category "float_const" for signed decimal
   179 fractions (e.g. 123.45 or -123.45).
   180 
   181 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   182 interface with 'setup' command instead.
   183 
   184 * Command 'local_setup' is similar to 'setup', but operates on a local
   185 theory context.
   186 
   187 * The 'axiomatization' command now only works within a global theory
   188 context.  INCOMPATIBILITY.
   189 
   190 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   191 hypotheses.  Sorts required in the course of reasoning need to be
   192 covered by the constraints in the initial statement, completed by the
   193 type instance information of the background theory.  Non-trivial sort
   194 hypotheses, which rarely occur in practice, may be specified via
   195 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   196 
   197   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   198 
   199 The result contains an implicit sort hypotheses as before --
   200 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   201 normalization.
   202 
   203 * Generalized Isar history, with support for linear undo, direct state
   204 addressing etc.
   205 
   206 * Changed defaults for unify configuration options:
   207 
   208   unify_trace_bound = 50 (formerly 25)
   209   unify_search_bound = 60 (formerly 30)
   210 
   211 * Different bookkeeping for code equations (INCOMPATIBILITY):
   212 
   213   a) On theory merge, the last set of code equations for a particular
   214      constant is taken (in accordance with the policy applied by other
   215      parts of the code generator framework).
   216 
   217   b) Code equations stemming from explicit declarations (e.g. code
   218      attribute) gain priority over default code equations stemming
   219      from definition, primrec, fun etc.
   220 
   221 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   222 
   223 * Unified theorem tables for both code generators.  Thus [code
   224 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   225 
   226 * Command 'find_consts' searches for constants based on type and name
   227 patterns, e.g.
   228 
   229     find_consts "_ => bool"
   230 
   231 By default, matching is against subtypes, but it may be restricted to
   232 the whole type.  Searching by name is possible.  Multiple queries are
   233 conjunctive and queries may be negated by prefixing them with a
   234 hyphen:
   235 
   236     find_consts strict: "_ => bool" name: "Int" -"int => int"
   237 
   238 * New 'find_theorems' criterion "solves" matches theorems that
   239 directly solve the current goal (modulo higher-order unification).
   240 
   241 * Auto solve feature for main theorem statements: whenever a new goal
   242 is stated, "find_theorems solves" is called; any theorems that could
   243 solve the lemma directly are listed as part of the goal state.
   244 Cf. associated options in Proof General Isabelle settings menu,
   245 enabled by default, with reasonable timeout for pathological cases of
   246 higher-order unification.
   247 
   248 
   249 *** Document preparation ***
   250 
   251 * Antiquotation @{lemma} now imitates a regular terminal proof,
   252 demanding keyword 'by' and supporting the full method expression
   253 syntax just like the Isar command 'by'.
   254 
   255 
   256 *** HOL ***
   257 
   258 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   259 points Main and Complex_Main remain as before.
   260 
   261 * Logic image HOL-Plain provides a minimal HOL with the most important
   262 tools available (inductive, datatype, primrec, ...).  This facilitates
   263 experimentation and tool development.  Note that user applications
   264 (and library theories) should never refer to anything below theory
   265 Main, as before.
   266 
   267 * Logic image HOL-Main stops at theory Main, and thus facilitates
   268 experimentation due to shorter build times.
   269 
   270 * Logic image HOL-NSA contains theories of nonstandard analysis which
   271 were previously part of former HOL-Complex.  Entry point Hyperreal
   272 remains valid, but theories formerly using Complex_Main should now use
   273 new entry point Hypercomplex.
   274 
   275 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   276 Posix processes.  Avoids potentially expensive forking of the ML
   277 process.  New thread-based implementation also works on non-Unix
   278 platforms (Cygwin).  Provers are no longer hardwired, but defined
   279 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   280 commands are covered in the isar-ref manual.
   281 
   282 * Wrapper scripts for remote SystemOnTPTP service allows to use
   283 sledgehammer without local ATP installation (Vampire etc.). Other
   284 provers may be included via suitable ML wrappers, see also
   285 src/HOL/ATP_Linkup.thy.
   286 
   287 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   288 menu.
   289 
   290 * The metis method no longer fails because the theorem is too trivial
   291 (contains the empty clause).
   292 
   293 * The metis method now fails in the usual manner, rather than raising
   294 an exception, if it determines that it cannot prove the theorem.
   295 
   296 * Method "coherent" implements a prover for coherent logic (see also
   297 src/Tools/coherent.ML).
   298 
   299 * Constants "undefined" and "default" replace "arbitrary".  Usually
   300 "undefined" is the right choice to replace "arbitrary", though
   301 logically there is no difference.  INCOMPATIBILITY.
   302 
   303 * Command "value" now integrates different evaluation mechanisms.  The
   304 result of the first successful evaluation mechanism is printed.  In
   305 square brackets a particular named evaluation mechanisms may be
   306 specified (currently, [SML], [code] or [nbe]).  See further
   307 src/HOL/ex/Eval_Examples.thy.
   308 
   309 * Normalization by evaluation now allows non-leftlinear equations.
   310 Declare with attribute [code nbe].
   311 
   312 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   313 as the structured Isar versions "cases" and "induct", cf. the
   314 corresponding "cases" and "induct" attributes.  Mutual induction rules
   315 are now presented as a list of individual projections
   316 (e.g. foo_bar.inducts for types foo and bar); the old format with
   317 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   318 rare situations a different rule is selected --- notably nested tuple
   319 elimination instead of former prod.exhaust: use explicit (case_tac t
   320 rule: prod.exhaust) here.
   321 
   322 * Attributes "cases", "induct", "coinduct" support "del" option.
   323 
   324 * Removed fact "case_split_thm", which duplicates "case_split".
   325 
   326 * The option datatype has been moved to a new theory Option.  Renamed
   327 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   328 
   329 * New predicate "strict_mono" classifies strict functions on partial
   330 orders.  With strict functions on linear orders, reasoning about
   331 (in)equalities is facilitated by theorems "strict_mono_eq",
   332 "strict_mono_less_eq" and "strict_mono_less".
   333 
   334 * Some set operations are now proper qualified constants with
   335 authentic syntax.  INCOMPATIBILITY:
   336 
   337     op Int ~>   Set.Int
   338     op Un ~>    Set.Un
   339     INTER ~>    Set.INTER
   340     UNION ~>    Set.UNION
   341     Inter ~>    Set.Inter
   342     Union ~>    Set.Union
   343     {} ~>       Set.empty
   344     UNIV ~>     Set.UNIV
   345 
   346 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   347 theory Set.
   348 
   349 * Auxiliary class "itself" has disappeared -- classes without any
   350 parameter are treated as expected by the 'class' command.
   351 
   352 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   353 
   354 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   355 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   356 
   357 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   358 method "approximation".  It proves formulas on real values by using
   359 interval arithmetic.  In the formulas are also the transcendental
   360 functions sin, cos, tan, atan, ln, exp and the constant pi are
   361 allowed. For examples see
   362 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   363 
   364 * Theory "Reflection" now resides in HOL/Library.
   365 
   366 * Entry point to Word library now simply named "Word".
   367 INCOMPATIBILITY.
   368 
   369 * Made source layout more coherent with logical distribution
   370 structure:
   371 
   372     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   373     src/HOL/Library/Code_Message.thy ~> src/HOL/
   374     src/HOL/Library/GCD.thy ~> src/HOL/
   375     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   376     src/HOL/Library/Parity.thy ~> src/HOL/
   377     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   378     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   379     src/HOL/Real/Lubs.thy ~> src/HOL/
   380     src/HOL/Real/PReal.thy ~> src/HOL/
   381     src/HOL/Real/Rational.thy ~> src/HOL/
   382     src/HOL/Real/RComplete.thy ~> src/HOL/
   383     src/HOL/Real/RealDef.thy ~> src/HOL/
   384     src/HOL/Real/RealPow.thy ~> src/HOL/
   385     src/HOL/Real/Real.thy ~> src/HOL/
   386     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   387     src/HOL/Complex/Complex.thy ~> src/HOL/
   388     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   389     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   390     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   391     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   392     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   393     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   394     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   395     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   396     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   397     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   398     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   399     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   400     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   401     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   402     src/HOL/Real/Float ~> src/HOL/Library/
   403     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   404     src/HOL/Real/RealVector.thy ~> src/HOL/
   405 
   406     src/HOL/arith_data.ML ~> src/HOL/Tools
   407     src/HOL/hologic.ML ~> src/HOL/Tools
   408     src/HOL/simpdata.ML ~> src/HOL/Tools
   409     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   410     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   411     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   412     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   413     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   414     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   415     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   416 
   417     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   418     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   419     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   420     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   421     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   422     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   423 
   424 * If methods "eval" and "evaluation" encounter a structured proof
   425 state with !!/==>, only the conclusion is evaluated to True (if
   426 possible), avoiding strange error messages.
   427 
   428 * Method "sizechange" automates termination proofs using (a
   429 modification of) the size-change principle.  Requires SAT solver.  See
   430 src/HOL/ex/Termination.thy for examples.
   431 
   432 * Simplifier: simproc for let expressions now unfolds if bound
   433 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   434 
   435 * Method "arith": Linear arithmetic now ignores all inequalities when
   436 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   437 
   438 * New attribute "arith" for facts that should always be used
   439 automatically by arithmetic. It is intended to be used locally in
   440 proofs, e.g.
   441 
   442   assumes [arith]: "x > 0"
   443 
   444 Global usage is discouraged because of possible performance impact.
   445 
   446 * New classes "top" and "bot" with corresponding operations "top" and
   447 "bot" in theory Orderings; instantiation of class "complete_lattice"
   448 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   449 
   450 * Changed definition lemma "less_fun_def" in order to provide an
   451 instance for preorders on functions; use lemma "less_le" instead.
   452 INCOMPATIBILITY.
   453 
   454 * Theory Orderings: class "wellorder" moved here, with explicit
   455 induction rule "less_induct" as assumption.  For instantiation of
   456 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   457 INCOMPATIBILITY.
   458 
   459 * Theory Orderings: added class "preorder" as superclass of "order".
   460 INCOMPATIBILITY: Instantiation proofs for order, linorder
   461 etc. slightly changed.  Some theorems named order_class.* now named
   462 preorder_class.*.
   463 
   464 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   465 "diag" to "Id_on".
   466 
   467 * Theory Finite_Set: added a new fold combinator of type
   468 
   469   ('a => 'b => 'b) => 'b => 'a set => 'b
   470 
   471 Occasionally this is more convenient than the old fold combinator
   472 which is now defined in terms of the new one and renamed to
   473 fold_image.
   474 
   475 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   476 and "ring_simps" have been replaced by "algebra_simps" (which can be
   477 extended with further lemmas!).  At the moment both still exist but
   478 the former will disappear at some point.
   479 
   480 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   481 class recpower.  Type-specific simp rules for various recpower types
   482 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   483 
   484 rat_power_0    -> power_0
   485 rat_power_Suc  -> power_Suc
   486 realpow_0      -> power_0
   487 realpow_Suc    -> power_Suc
   488 complexpow_0   -> power_0
   489 complexpow_Suc -> power_Suc
   490 power_poly_0   -> power_0
   491 power_poly_Suc -> power_Suc
   492 
   493 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   494 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   495 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   496 of lemmas from Divides has been generalized from nat to class
   497 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   498 renames resulting from duplicate elimination:
   499 
   500     dvd_def_mod ~>          dvd_eq_mod_eq_0
   501     zero_dvd_iff ~>         dvd_0_left_iff
   502     dvd_0 ~>                dvd_0_right
   503     DIVISION_BY_ZERO_DIV ~> div_by_0
   504     DIVISION_BY_ZERO_MOD ~> mod_by_0
   505     mult_div ~>             div_mult_self2_is_id
   506     mult_mod ~>             mod_mult_self2_is_0
   507 
   508 * Theory IntDiv: removed many lemmas that are instances of class-based
   509 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   510 rename old lemmas as follows:
   511 
   512 dvd_diff               -> nat_dvd_diff
   513 dvd_zminus_iff         -> dvd_minus_iff
   514 mod_add1_eq            -> mod_add_eq
   515 mod_mult1_eq           -> mod_mult_right_eq
   516 mod_mult1_eq'          -> mod_mult_left_eq
   517 mod_mult_distrib_mod   -> mod_mult_eq
   518 nat_mod_add_left_eq    -> mod_add_left_eq
   519 nat_mod_add_right_eq   -> mod_add_right_eq
   520 nat_mod_div_trivial    -> mod_div_trivial
   521 nat_mod_mod_trivial    -> mod_mod_trivial
   522 zdiv_zadd_self1        -> div_add_self1
   523 zdiv_zadd_self2        -> div_add_self2
   524 zdiv_zmult_self1       -> div_mult_self2_is_id
   525 zdiv_zmult_self2       -> div_mult_self1_is_id
   526 zdvd_triv_left         -> dvd_triv_left
   527 zdvd_triv_right        -> dvd_triv_right
   528 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   529 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   530 zmod_zadd_left_eq      -> mod_add_left_eq
   531 zmod_zadd_right_eq     -> mod_add_right_eq
   532 zmod_zadd_self1        -> mod_add_self1
   533 zmod_zadd_self2        -> mod_add_self2
   534 zmod_zadd1_eq          -> mod_add_eq
   535 zmod_zdiff1_eq         -> mod_diff_eq
   536 zmod_zdvd_zmod         -> mod_mod_cancel
   537 zmod_zmod_cancel       -> mod_mod_cancel
   538 zmod_zmult_self1       -> mod_mult_self2_is_0
   539 zmod_zmult_self2       -> mod_mult_self1_is_0
   540 zmod_1                 -> mod_by_1
   541 zdiv_1                 -> div_by_1
   542 zdvd_abs1              -> abs_dvd_iff
   543 zdvd_abs2              -> dvd_abs_iff
   544 zdvd_refl              -> dvd_refl
   545 zdvd_trans             -> dvd_trans
   546 zdvd_zadd              -> dvd_add
   547 zdvd_zdiff             -> dvd_diff
   548 zdvd_zminus_iff        -> dvd_minus_iff
   549 zdvd_zminus2_iff       -> minus_dvd_iff
   550 zdvd_zmultD            -> dvd_mult_right
   551 zdvd_zmultD2           -> dvd_mult_left
   552 zdvd_zmult_mono        -> mult_dvd_mono
   553 zdvd_0_right           -> dvd_0_right
   554 zdvd_0_left            -> dvd_0_left_iff
   555 zdvd_1_left            -> one_dvd
   556 zminus_dvd_iff         -> minus_dvd_iff
   557 
   558 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   559 
   560 * The real numbers offer decimal input syntax: 12.34 is translated
   561 into 1234/10^2. This translation is not reversed upon output.
   562 
   563 * Theory Library/Polynomial defines an abstract type 'a poly of
   564 univariate polynomials with coefficients of type 'a.  In addition to
   565 the standard ring operations, it also supports div and mod.  Code
   566 generation is also supported, using list-style constructors.
   567 
   568 * Theory Library/Inner_Product defines a class of real_inner for real
   569 inner product spaces, with an overloaded operation inner :: 'a => 'a
   570 => real.  Class real_inner is a subclass of real_normed_vector from
   571 theory RealVector.
   572 
   573 * Theory Library/Product_Vector provides instances for the product
   574 type 'a * 'b of several classes from RealVector and Inner_Product.
   575 Definitions of addition, subtraction, scalar multiplication, norms,
   576 and inner products are included.
   577 
   578 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   579 addition to the field operations, numerals and case syntax are also
   580 supported.
   581 
   582 * Theory Library/Diagonalize provides constructive version of Cantor's
   583 first diagonalization argument.
   584 
   585 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   586 zlcm (for int); carried together from various gcd/lcm developements in
   587 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   588 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   589 may recover tupled syntax as follows:
   590 
   591     hide (open) const gcd
   592     abbreviation gcd where
   593       "gcd == (%(a, b). GCD.gcd a b)"
   594     notation (output)
   595       GCD.gcd ("gcd '(_, _')")
   596 
   597 The same works for lcm, zgcd, zlcm.
   598 
   599 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   600 instantiations for algebraic structures.  Removed some duplicate
   601 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   602 
   603 * ML antiquotation @{code} takes a constant as argument and generates
   604 corresponding code in background and inserts name of the corresponding
   605 resulting ML value/function/datatype constructor binding in place.
   606 All occurrences of @{code} with a single ML block are generated
   607 simultaneously.  Provides a generic and safe interface for
   608 instrumentalizing code generation.  See
   609 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   610 In future you ought to refrain from ad-hoc compiling generated SML
   611 code on the ML toplevel.  Note that (for technical reasons) @{code}
   612 cannot refer to constants for which user-defined serializations are
   613 set.  Refer to the corresponding ML counterpart directly in that
   614 cases.
   615 
   616 * Command 'rep_datatype': instead of theorem names the command now
   617 takes a list of terms denoting the constructors of the type to be
   618 represented as datatype.  The characteristic theorems have to be
   619 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   620 have disappeared in favour of existing ones:
   621 
   622     unit_induct                 ~> unit.induct
   623     prod_induct                 ~> prod.induct
   624     sum_induct                  ~> sum.induct
   625     Suc_Suc_eq                  ~> nat.inject
   626     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   627 
   628 
   629 *** HOL-Algebra ***
   630 
   631 * New locales for orders and lattices where the equivalence relation
   632 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   633 locales use a record structure with field eq for the equivalence.
   634 
   635 * New theory of factorial domains.
   636 
   637 * Units_l_inv and Units_r_inv are now simp rules by default.
   638 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   639 and/or r_inv will now also require deletion of these lemmas.
   640 
   641 * Renamed the following theorems, INCOMPATIBILITY:
   642 
   643 UpperD ~> Upper_memD
   644 LowerD ~> Lower_memD
   645 least_carrier ~> least_closed
   646 greatest_carrier ~> greatest_closed
   647 greatest_Lower_above ~> greatest_Lower_below
   648 one_zero ~> carrier_one_zero
   649 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   650 
   651 
   652 *** HOL-Nominal ***
   653 
   654 * Nominal datatypes can now contain type-variables.
   655 
   656 * Commands 'nominal_inductive' and 'equivariance' work with local
   657 theory targets.
   658 
   659 * Nominal primrec can now works with local theory targets and its
   660 specification syntax now conforms to the general format as seen in
   661 'inductive' etc.
   662 
   663 * Method "perm_simp" honours the standard simplifier attributes
   664 (no_asm), (no_asm_use) etc.
   665 
   666 * The new predicate #* is defined like freshness, except that on the
   667 left hand side can be a set or list of atoms.
   668 
   669 * Experimental command 'nominal_inductive2' derives strong induction
   670 principles for inductive definitions.  In contrast to
   671 'nominal_inductive', which can only deal with a fixed number of
   672 binders, it can deal with arbitrary expressions standing for sets of
   673 atoms to be avoided.  The only inductive definition we have at the
   674 moment that needs this generalisation is the typing rule for Lets in
   675 the algorithm W:
   676 
   677  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   678  -----------------------------------------------------------------
   679          Gamma |- Let x be t1 in t2 : T2
   680 
   681 In this rule one wants to avoid all the binders that are introduced by
   682 "close Gamma T1".  We are looking for other examples where this
   683 feature might be useful.  Please let us know.
   684 
   685 
   686 *** HOLCF ***
   687 
   688 * Reimplemented the simplification procedure for proving continuity
   689 subgoals.  The new simproc is extensible; users can declare additional
   690 continuity introduction rules with the attribute [cont2cont].
   691 
   692 * The continuity simproc now uses a different introduction rule for
   693 solving continuity subgoals on terms with lambda abstractions.  In
   694 some rare cases the new simproc may fail to solve subgoals that the
   695 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   696 Potential INCOMPATIBILITY.
   697 
   698 * Command 'fixrec': specification syntax now conforms to the general
   699 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   700 examples.  INCOMPATIBILITY.
   701 
   702 
   703 *** ZF ***
   704 
   705 * Proof of Zorn's Lemma for partial orders.
   706 
   707 
   708 *** ML ***
   709 
   710 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   711 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   712 depends on multithreading, so timouts will not work before Poly/ML
   713 5.2.1!
   714 
   715 * High-level support for concurrent ML programming, see
   716 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   717 particularly convenient to organize independent functional
   718 computations.  The concept of "synchronized variables" provides a
   719 higher-order interface for components with shared state, avoiding the
   720 delicate details of mutexes and condition variables.  (Requires
   721 Poly/ML 5.2.1 or later.)
   722 
   723 * ML bindings produced via Isar commands are stored within the Isar
   724 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   725 become thread-safe and work with undo as expected (concerning
   726 top-level bindings, not side-effects on global references).
   727 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   728 compiler at runtime; really global bindings need to be given outside a
   729 theory.  (Requires Poly/ML 5.2 or later.)
   730 
   731 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   732 context.  Top-level ML bindings are stored within the proof context in
   733 a purely sequential fashion, disregarding the nested proof structure.
   734 ML bindings introduced by 'ML_prf' are discarded at the end of the
   735 proof.  (Requires Poly/ML 5.2 or later.)
   736 
   737 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   738 and Method.setup, as well as Isar commands 'attribute_setup' and
   739 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   740 existing code accordingly, or use plain 'setup' together with old
   741 Method.add_method.
   742 
   743 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   744 to 'a -> thm, while results are always tagged with an authentic oracle
   745 name.  The Isar command 'oracle' is now polymorphic, no argument type
   746 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   747 accordingly.  Note that extra performance may be gained by producing
   748 the cterm carefully, avoiding slow Thm.cterm_of.
   749 
   750 * Simplified interface for defining document antiquotations via
   751 ThyOutput.antiquotation, ThyOutput.output, and optionally
   752 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   753 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   754 examples.
   755 
   756 * More systematic treatment of long names, abstract name bindings, and
   757 name space operations.  Basic operations on qualified names have been
   758 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   759 Long_Name.append.  Old type bstring has been mostly replaced by
   760 abstract type binding (see structure Binding), which supports precise
   761 qualification by packages and local theory targets, as well as proper
   762 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   763 bstring values into Binding.name, or better pass through abstract
   764 bindings everywhere.  See further src/Pure/General/long_name.ML,
   765 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   766 
   767 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   768 LocalTheory.note etc.) now refer to the *full* internal name, not the
   769 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   770 
   771 * Disposed old type and term read functions (Sign.read_def_typ,
   772 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   773 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   774 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   775 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   776 resort for legacy applications.
   777 
   778 * Disposed old declarations, tactics, tactic combinators that refer to
   779 the simpset or claset of an implicit theory (such as Addsimps,
   780 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   781 embedded ML text, or local_simpset_of with a proper context passed as
   782 explicit runtime argument.
   783 
   784 * Rules and tactics that read instantiations (read_instantiate,
   785 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   786 context, which is required for parsing and type-checking.  Moreover,
   787 the variables are specified as plain indexnames, not string encodings
   788 thereof.  INCOMPATIBILITY.
   789 
   790 * Generic Toplevel.add_hook interface allows to analyze the result of
   791 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   792 for theorem dependency output of transactions resulting in a new
   793 theory state.
   794 
   795 * ML antiquotations: block-structured compilation context indicated by
   796 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   797 
   798   @{binding name}                         - basic name binding
   799   @{let ?pat = term}                      - term abbreviation (HO matching)
   800   @{note name = fact}                     - fact abbreviation
   801   @{thm fact}                             - singleton fact (with attributes)
   802   @{thms fact}                            - general fact (with attributes)
   803   @{lemma prop by method}                 - singleton goal
   804   @{lemma prop by meth1 meth2}            - singleton goal
   805   @{lemma prop1 ... propN by method}      - general goal
   806   @{lemma prop1 ... propN by meth1 meth2} - general goal
   807   @{lemma (open) ...}                     - open derivation
   808 
   809 
   810 *** System ***
   811 
   812 * The Isabelle "emacs" tool provides a specific interface to invoke
   813 Proof General / Emacs, with more explicit failure if that is not
   814 installed (the old isabelle-interface script silently falls back on
   815 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   816 installation location of the Proof General distribution.
   817 
   818 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   819 the Isabelle process into a JVM/Scala application.  See
   820 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   821 process wrapper has been discontinued.)
   822 
   823 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   824 
   825 * Various status messages (with exact source position information) are
   826 emitted, if proper markup print mode is enabled.  This allows
   827 user-interface components to provide detailed feedback on internal
   828 prover operations.
   829 
   830 
   831 
   832 New in Isabelle2008 (June 2008)
   833 -------------------------------
   834 
   835 *** General ***
   836 
   837 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   838 and updated, with formally checked references as hyperlinks.
   839 
   840 * Theory loader: use_thy (and similar operations) no longer set the
   841 implicit ML context, which was occasionally hard to predict and in
   842 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   843 provides a proper context already.
   844 
   845 * Theory loader: old-style ML proof scripts being *attached* to a thy
   846 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   847 'use' within a theory file will do the job.
   848 
   849 * Name space merge now observes canonical order, i.e. the second space
   850 is inserted into the first one, while existing entries in the first
   851 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   852 swap theory imports.
   853 
   854 * Syntax: symbol \<chi> is now considered a letter.  Potential
   855 INCOMPATIBILITY in identifier syntax etc.
   856 
   857 * Outer syntax: string tokens no longer admit escaped white space,
   858 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   859 white space without escapes.
   860 
   861 * Outer syntax: string tokens may contain arbitrary character codes
   862 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   863 "foo_bar".
   864 
   865 
   866 *** Pure ***
   867 
   868 * Context-dependent token translations.  Default setup reverts locally
   869 fixed variables, and adds hilite markup for undeclared frees.
   870 
   871 * Unused theorems can be found using the new command 'unused_thms'.
   872 There are three ways of invoking it:
   873 
   874 (1) unused_thms
   875      Only finds unused theorems in the current theory.
   876 
   877 (2) unused_thms thy_1 ... thy_n -
   878      Finds unused theorems in the current theory and all of its ancestors,
   879      excluding the theories thy_1 ... thy_n and all of their ancestors.
   880 
   881 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   882      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   883      their ancestors, excluding the theories thy_1 ... thy_n and all of
   884      their ancestors.
   885 
   886 In order to increase the readability of the list produced by
   887 unused_thms, theorems that have been created by a particular instance
   888 of a theory command such as 'inductive' or 'function' are considered
   889 to belong to the same "group", meaning that if at least one theorem in
   890 this group is used, the other theorems in the same group are no longer
   891 reported as unused.  Moreover, if all theorems in the group are
   892 unused, only one theorem in the group is displayed.
   893 
   894 Note that proof objects have to be switched on in order for
   895 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   896 usually the case when using Proof General with the default settings).
   897 
   898 * Authentic naming of facts disallows ad-hoc overwriting of previous
   899 theorems within the same name space.  INCOMPATIBILITY, need to remove
   900 duplicate fact bindings, or even accidental fact duplications.  Note
   901 that tools may maintain dynamically scoped facts systematically, using
   902 PureThy.add_thms_dynamic.
   903 
   904 * Command 'hide' now allows to hide from "fact" name space as well.
   905 
   906 * Eliminated destructive theorem database, simpset, claset, and
   907 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   908 update of theories within ML code.
   909 
   910 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   911 INCOMPATIBILITY, object-logics depending on former Pure require
   912 additional setup PureThy.old_appl_syntax_setup; object-logics
   913 depending on former CPure need to refer to Pure.
   914 
   915 * Commands 'use' and 'ML' are now purely functional, operating on
   916 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   917 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   918 INCOMPATIBILITY.
   919 
   920 * Command 'setup': discontinued implicit version with ML reference.
   921 
   922 * Instantiation target allows for simultaneous specification of class
   923 instance operations together with an instantiation proof.
   924 Type-checking phase allows to refer to class operations uniformly.
   925 See src/HOL/Complex/Complex.thy for an Isar example and
   926 src/HOL/Library/Eval.thy for an ML example.
   927 
   928 * Indexing of literal facts: be more serious about including only
   929 facts from the visible specification/proof context, but not the
   930 background context (locale etc.).  Affects `prop` notation and method
   931 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   932 situations.
   933 
   934 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   935 "(open)" option, which used to expose internal bound variables to the
   936 proof text.
   937 
   938 * Isar statements: removed obsolete case "rule_context".
   939 INCOMPATIBILITY, better use explicit fixes/assumes.
   940 
   941 * Locale proofs: default proof step now includes 'unfold_locales';
   942 hence 'proof' without argument may be used to unfold locale
   943 predicates.
   944 
   945 
   946 *** Document preparation ***
   947 
   948 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   949 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   950 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   951 spot); renamed link color from "darkblue" to "linkcolor" (default
   952 value unchanged, can be redefined via \definecolor); no longer sets
   953 "a4paper" option (unnecessary or even intrusive).
   954 
   955 * Antiquotation @{lemma A method} proves proposition A by the given
   956 method (either a method name or a method name plus (optional) method
   957 arguments in parentheses) and prints A just like @{prop A}.
   958 
   959 
   960 *** HOL ***
   961 
   962 * New primrec package.  Specification syntax conforms in style to
   963 definition/function/....  No separate induction rule is provided.  The
   964 "primrec" command distinguishes old-style and new-style specifications
   965 by syntax.  The former primrec package is now named OldPrimrecPackage.
   966 When adjusting theories, beware: constants stemming from new-style
   967 primrec specifications have authentic syntax.
   968 
   969 * Metis prover is now an order of magnitude faster, and also works
   970 with multithreading.
   971 
   972 * Metis: the maximum number of clauses that can be produced from a
   973 theorem is now given by the attribute max_clauses.  Theorems that
   974 exceed this number are ignored, with a warning printed.
   975 
   976 * Sledgehammer no longer produces structured proofs by default. To
   977 enable, declare [[sledgehammer_full = true]].  Attributes
   978 reconstruction_modulus, reconstruction_sorts renamed
   979 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   980 
   981 * Method "induct_scheme" derives user-specified induction rules
   982 from well-founded induction and completeness of patterns. This factors
   983 out some operations that are done internally by the function package
   984 and makes them available separately.  See
   985 src/HOL/ex/Induction_Scheme.thy for examples.
   986 
   987 * More flexible generation of measure functions for termination
   988 proofs: Measure functions can be declared by proving a rule of the
   989 form "is_measure f" and giving it the [measure_function] attribute.
   990 The "is_measure" predicate is logically meaningless (always true), and
   991 just guides the heuristic.  To find suitable measure functions, the
   992 termination prover sets up the goal "is_measure ?f" of the appropriate
   993 type and generates all solutions by prolog-style backwards proof using
   994 the declared rules.
   995 
   996 This setup also deals with rules like 
   997 
   998   "is_measure f ==> is_measure (list_size f)"
   999 
  1000 which accommodates nested datatypes that recurse through lists.
  1001 Similar rules are predeclared for products and option types.
  1002 
  1003 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
  1004 
  1005   INCOMPATIBILITIES:
  1006 
  1007   - Definitions of overloaded constants on sets have to be replaced by
  1008     definitions on => and bool.
  1009 
  1010   - Some definitions of overloaded operators on sets can now be proved
  1011     using the definitions of the operators on => and bool.  Therefore,
  1012     the following theorems have been renamed:
  1013 
  1014       subset_def   -> subset_eq
  1015       psubset_def  -> psubset_eq
  1016       set_diff_def -> set_diff_eq
  1017       Compl_def    -> Compl_eq
  1018       Sup_set_def  -> Sup_set_eq
  1019       Inf_set_def  -> Inf_set_eq
  1020       sup_set_def  -> sup_set_eq
  1021       inf_set_def  -> inf_set_eq
  1022 
  1023   - Due to the incompleteness of the HO unification algorithm, some
  1024     rules such as subst may require manual instantiation, if some of
  1025     the unknowns in the rule is a set.
  1026 
  1027   - Higher order unification and forward proofs:
  1028     The proof pattern
  1029 
  1030       have "P (S::'a set)" <...>
  1031       then have "EX S. P S" ..
  1032 
  1033     no longer works (due to the incompleteness of the HO unification
  1034     algorithm) and must be replaced by the pattern
  1035 
  1036       have "EX S. P S"
  1037       proof
  1038         show "P S" <...>
  1039       qed
  1040 
  1041   - Calculational reasoning with subst (or similar rules):
  1042     The proof pattern
  1043 
  1044       have "P (S::'a set)" <...>
  1045       also have "S = T" <...>
  1046       finally have "P T" .
  1047 
  1048     no longer works (for similar reasons as the previous example) and
  1049     must be replaced by something like
  1050 
  1051       have "P (S::'a set)" <...>
  1052       moreover have "S = T" <...>
  1053       ultimately have "P T" by simp
  1054 
  1055   - Tactics or packages written in ML code:
  1056     Code performing pattern matching on types via
  1057 
  1058       Type ("set", [T]) => ...
  1059 
  1060     must be rewritten. Moreover, functions like strip_type or
  1061     binder_types no longer return the right value when applied to a
  1062     type of the form
  1063 
  1064       T1 => ... => Tn => U => bool
  1065 
  1066     rather than
  1067 
  1068       T1 => ... => Tn => U set
  1069 
  1070 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1071 Wellfounded_Relations to theory Wellfounded.
  1072 
  1073 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1074 
  1075 * Class finite no longer treats UNIV as class parameter.  Use class
  1076 enum from theory Library/Enum instead to achieve a similar effect.
  1077 INCOMPATIBILITY.
  1078 
  1079 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1080 and "Cons".  INCOMPATIBILITY.
  1081 
  1082 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1083 Potential INCOMPATIBILITY.
  1084 
  1085 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1086 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1087 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1088 
  1089 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1090 the same name in theory Orderings:
  1091 
  1092   less_trans
  1093   less_linear
  1094   le_imp_less_or_eq
  1095   le_less_trans
  1096   less_le_trans
  1097   less_not_sym
  1098   less_asym
  1099 
  1100 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1101 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1102 and different variable names.
  1103 
  1104 * Library/Option_ord.thy: Canonical order on option type.
  1105 
  1106 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1107 finite maps.
  1108 
  1109 * Library/Countable.thy: Type class for countable types.
  1110 
  1111 * Theory Int: The representation of numerals has changed.  The infix
  1112 operator BIT and the bit datatype with constructors B0 and B1 have
  1113 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1114 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1115 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1116 accordingly.
  1117 
  1118 * Theory Nat: definition of <= and < on natural numbers no longer
  1119 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1120 le_def and less_def have disappeared.  Consider lemmas not_less
  1121 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1122 
  1123 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1124 (whose purpose mainly is for various fold_set functionals) have been
  1125 abandoned in favor of the existing algebraic classes
  1126 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1127 lower_semilattice (resp. upper_semilattice) and linorder.
  1128 INCOMPATIBILITY.
  1129 
  1130 * Theory Transitive_Closure: induct and cases rules now declare proper
  1131 case_names ("base" and "step").  INCOMPATIBILITY.
  1132 
  1133 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1134 lattices.  The form set-specific version is available as
  1135 Inductive.lfp_ordinal_induct_set.
  1136 
  1137 * Renamed theorems "power.simps" to "power_int.simps".
  1138 INCOMPATIBILITY.
  1139 
  1140 * Class semiring_div provides basic abstract properties of semirings
  1141 with division and modulo operations.  Subsumes former class dvd_mod.
  1142 
  1143 * Merged theories IntDef, Numeral and IntArith into unified theory
  1144 Int.  INCOMPATIBILITY.
  1145 
  1146 * Theory Library/Code_Index: type "index" now represents natural
  1147 numbers rather than integers.  INCOMPATIBILITY.
  1148 
  1149 * New class "uminus" with operation "uminus" (split of from class
  1150 "minus" which now only has operation "minus", binary).
  1151 INCOMPATIBILITY.
  1152 
  1153 * Constants "card", "internal_split", "option_map" now with authentic
  1154 syntax.  INCOMPATIBILITY.
  1155 
  1156 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1157 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1158 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1159 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1160 Sup_set_def, le_def, less_def, option_map_def now with object
  1161 equality.  INCOMPATIBILITY.
  1162 
  1163 * Records. Removed K_record, and replaced it by pure lambda term
  1164 %x. c. The simplifier setup is now more robust against eta expansion.
  1165 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1166 
  1167 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1168 
  1169 * Library/ListVector: new theory of arithmetic vector operations.
  1170 
  1171 * Library/Order_Relation: new theory of various orderings as sets of
  1172 pairs.  Defines preorders, partial orders, linear orders and
  1173 well-orders on sets and on types.
  1174 
  1175 
  1176 *** ZF ***
  1177 
  1178 * Renamed some theories to allow to loading both ZF and HOL in the
  1179 same session:
  1180 
  1181   Datatype  -> Datatype_ZF
  1182   Inductive -> Inductive_ZF
  1183   Int       -> Int_ZF
  1184   IntDiv    -> IntDiv_ZF
  1185   Nat       -> Nat_ZF
  1186   List      -> List_ZF
  1187   Main      -> Main_ZF
  1188 
  1189 INCOMPATIBILITY: ZF theories that import individual theories below
  1190 Main might need to be adapted.  Regular theory Main is still
  1191 available, as trivial extension of Main_ZF.
  1192 
  1193 
  1194 *** ML ***
  1195 
  1196 * ML within Isar: antiquotation @{const name} or @{const
  1197 name(typargs)} produces statically-checked Const term.
  1198 
  1199 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1200 (of the same name).  Removed obsolete print command.
  1201 
  1202 * Removed obsolete "use_legacy_bindings" function.
  1203 
  1204 * The ``print mode'' is now a thread-local value derived from a global
  1205 template (the former print_mode reference), thus access becomes
  1206 non-critical.  The global print_mode reference is for session
  1207 management only; user-code should use print_mode_value,
  1208 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1209 
  1210 * Functions system/system_out provide a robust way to invoke external
  1211 shell commands, with propagation of interrupts (requires Poly/ML
  1212 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1213 
  1214 
  1215 *** System ***
  1216 
  1217 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1218 in accordance with Proof General 3.7, which prefers GNU emacs.
  1219 
  1220 * isatool tty runs Isabelle process with plain tty interaction;
  1221 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1222 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1223 
  1224 * isatool browser now works with Cygwin as well, using general
  1225 "javapath" function defined in Isabelle process environment.
  1226 
  1227 * YXML notation provides a simple and efficient alternative to
  1228 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1229 isatool yxml as described in the Isabelle system manual.
  1230 
  1231 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1232 provides general wrapper for managing an Isabelle process in a robust
  1233 fashion, with ``cooked'' output from stdin/stderr.
  1234 
  1235 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1236 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1237 
  1238 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1239 way of changing the user's settings is via
  1240 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1241 script.
  1242 
  1243 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1244 cores of the underlying machine, which is a good starting point for
  1245 optimal performance tuning.  The corresponding usedir option -M allows
  1246 "max" as an alias for "0".  WARNING: does not work on certain versions
  1247 of Mac OS (with Poly/ML 5.1).
  1248 
  1249 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1250 adverse effect of Isabelle flooding interactive front-ends (notably
  1251 ProofGeneral / XEmacs).
  1252 
  1253 
  1254 
  1255 New in Isabelle2007 (November 2007)
  1256 -----------------------------------
  1257 
  1258 *** General ***
  1259 
  1260 * More uniform information about legacy features, notably a
  1261 warning/error of "Legacy feature: ...", depending on the state of the
  1262 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1263 legacy features will disappear eventually.
  1264 
  1265 * Theory syntax: the header format ``theory A = B + C:'' has been
  1266 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1267 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1268 
  1269 * Theory syntax: the old non-Isar theory file format has been
  1270 discontinued altogether.  Note that ML proof scripts may still be used
  1271 with Isar theories; migration is usually quite simple with the ML
  1272 function use_legacy_bindings.  INCOMPATIBILITY.
  1273 
  1274 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1275 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1276 quotes.
  1277 
  1278 * Theory loader: be more serious about observing the static theory
  1279 header specifications (including optional directories), but not the
  1280 accidental file locations of previously successful loads.  The strict
  1281 update policy of former update_thy is now already performed by
  1282 use_thy, so the former has been removed; use_thys updates several
  1283 theories simultaneously, just as 'imports' within a theory header
  1284 specification, but without merging the results.  Potential
  1285 INCOMPATIBILITY: may need to refine theory headers and commands
  1286 ROOT.ML which depend on load order.
  1287 
  1288 * Theory loader: optional support for content-based file
  1289 identification, instead of the traditional scheme of full physical
  1290 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1291 (cf. the system manual).  The new scheme allows to work with
  1292 non-finished theories in persistent session images, such that source
  1293 files may be moved later on without requiring reloads.
  1294 
  1295 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1296 file (with the same base name as the theory) are considered a legacy
  1297 feature, which will disappear eventually. Even now, the theory loader
  1298 no longer maintains dependencies on such files.
  1299 
  1300 * Syntax: the scope for resolving ambiguities via type-inference is
  1301 now limited to individual terms, instead of whole simultaneous
  1302 specifications as before. This greatly reduces the complexity of the
  1303 syntax module and improves flexibility by separating parsing and
  1304 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1305 'fixes' etc.) are required in rare situations.
  1306 
  1307 * Syntax: constants introduced by new-style packages ('definition',
  1308 'abbreviation' etc.) are passed through the syntax module in
  1309 ``authentic mode''. This means that associated mixfix annotations
  1310 really stick to such constants, independently of potential name space
  1311 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1312 trees are represented slightly differently, may need to adapt syntax
  1313 translations accordingly. Use CONST marker in 'translations' and
  1314 @{const_syntax} antiquotation in 'parse_translation' etc.
  1315 
  1316 * Legacy goal package: reduced interface to the bare minimum required
  1317 to keep existing proof scripts running.  Most other user-level
  1318 functions are now part of the OldGoals structure, which is *not* open
  1319 by default (consider isatool expandshort before open OldGoals).
  1320 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1321 these tend to cause confusion about the actual goal (!) context being
  1322 used here, which is not necessarily the same as the_context().
  1323 
  1324 * Command 'find_theorems': supports "*" wild-card in "name:"
  1325 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1326 support a specific search form (see ProofGeneral/CHANGES).
  1327 
  1328 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1329 by default, which means that "prems" (and also "fixed variables") are
  1330 suppressed from proof state output.  Note that the ProofGeneral
  1331 settings mechanism allows to change and save options persistently, but
  1332 older versions of Isabelle will fail to start up if a negative prems
  1333 limit is imposed.
  1334 
  1335 * Local theory targets may be specified by non-nested blocks of
  1336 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1337 contain definitions, theorems etc., including any derived mechanism
  1338 that has been implemented on top of these primitives.  This concept
  1339 generalizes the existing ``theorem (in ...)'' towards more versatility
  1340 and scalability.
  1341 
  1342 * Proof General interface: proper undo of final 'end' command;
  1343 discontinued Isabelle/classic mode (ML proof scripts).
  1344 
  1345 
  1346 *** Document preparation ***
  1347 
  1348 * Added antiquotation @{theory name} which prints the given name,
  1349 after checking that it refers to a valid ancestor theory in the
  1350 current context.
  1351 
  1352 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1353 check the given source text as ML type/structure, printing verbatim.
  1354 
  1355 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1356 "c args == rhs" given in the current context.  (Any number of
  1357 arguments may be given on the LHS.)
  1358 
  1359 
  1360 *** Pure ***
  1361 
  1362 * The 'class' package offers a combination of axclass and locale to
  1363 achieve Haskell-like type classes in Isabelle.  Definitions and
  1364 theorems within a class context produce both relative results (with
  1365 implicit parameters according to the locale context), and polymorphic
  1366 constants with qualified polymorphism (according to the class
  1367 context).  Within the body context of a 'class' target, a separate
  1368 syntax layer ("user space type system") takes care of converting
  1369 between global polymorphic consts and internal locale representation.
  1370 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1371 "isatool doc classes" provides a tutorial.
  1372 
  1373 * Generic code generator framework allows to generate executable
  1374 code for ML and Haskell (including Isabelle classes).  A short usage
  1375 sketch:
  1376 
  1377     internal compilation:
  1378         export_code <list of constants (term syntax)> in SML
  1379     writing SML code to a file:
  1380         export_code <list of constants (term syntax)> in SML <filename>
  1381     writing OCaml code to a file:
  1382         export_code <list of constants (term syntax)> in OCaml <filename>
  1383     writing Haskell code to a bunch of files:
  1384         export_code <list of constants (term syntax)> in Haskell <filename>
  1385 
  1386     evaluating closed propositions to True/False using code generation:
  1387         method ``eval''
  1388 
  1389 Reasonable default setup of framework in HOL.
  1390 
  1391 Theorem attributs for selecting and transforming function equations theorems:
  1392 
  1393     [code fun]:        select a theorem as function equation for a specific constant
  1394     [code fun del]:    deselect a theorem as function equation for a specific constant
  1395     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1396     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1397 
  1398 User-defined serializations (target in {SML, OCaml, Haskell}):
  1399 
  1400     code_const <and-list of constants (term syntax)>
  1401       {(target) <and-list of const target syntax>}+
  1402 
  1403     code_type <and-list of type constructors>
  1404       {(target) <and-list of type target syntax>}+
  1405 
  1406     code_instance <and-list of instances>
  1407       {(target)}+
  1408         where instance ::= <type constructor> :: <class>
  1409 
  1410     code_class <and_list of classes>
  1411       {(target) <and-list of class target syntax>}+
  1412         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1413 
  1414 code_instance and code_class only are effective to target Haskell.
  1415 
  1416 For example usage see src/HOL/ex/Codegenerator.thy and
  1417 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1418 generation from Isabelle/HOL theories is available via "isatool doc
  1419 codegen".
  1420 
  1421 * Code generator: consts in 'consts_code' Isar commands are now
  1422 referred to by usual term syntax (including optional type
  1423 annotations).
  1424 
  1425 * Command 'no_translations' removes translation rules from theory
  1426 syntax.
  1427 
  1428 * Overloaded definitions are now actually checked for acyclic
  1429 dependencies.  The overloading scheme is slightly more general than
  1430 that of Haskell98, although Isabelle does not demand an exact
  1431 correspondence to type class and instance declarations.
  1432 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1433 exotic versions of overloading -- at the discretion of the user!
  1434 
  1435 Polymorphic constants are represented via type arguments, i.e. the
  1436 instantiation that matches an instance against the most general
  1437 declaration given in the signature.  For example, with the declaration
  1438 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1439 as c(nat).  Overloading is essentially simultaneous structural
  1440 recursion over such type arguments.  Incomplete specification patterns
  1441 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1442 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1443 Command 'print_theory' outputs the normalized system of recursive
  1444 equations, see section "definitions".
  1445 
  1446 * Configuration options are maintained within the theory or proof
  1447 context (with name and type bool/int/string), providing a very simple
  1448 interface to a poor-man's version of general context data.  Tools may
  1449 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1450 these values using Config.get etc.  Users may change options via an
  1451 associated attribute of the same name.  This form of context
  1452 declaration works particularly well with commands 'declare' or
  1453 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1454 very easy to avoid global references, which would not observe Isar
  1455 toplevel undo/redo and fail to work with multithreading.
  1456 
  1457 Various global ML references of Pure and HOL have been turned into
  1458 configuration options:
  1459 
  1460   Unify.search_bound		unify_search_bound
  1461   Unify.trace_bound		unify_trace_bound
  1462   Unify.trace_simp		unify_trace_simp
  1463   Unify.trace_types		unify_trace_types
  1464   Simplifier.simp_depth_limit	simp_depth_limit
  1465   Blast.depth_limit		blast_depth_limit
  1466   DatatypeProp.dtK		datatype_distinctness_limit
  1467   fast_arith_neq_limit  	fast_arith_neq_limit
  1468   fast_arith_split_limit	fast_arith_split_limit
  1469 
  1470 * Named collections of theorems may be easily installed as context
  1471 data using the functor NamedThmsFun (see also
  1472 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1473 attributes; there is also a toplevel print command.  This facility is
  1474 just a common case of general context data, which is the preferred way
  1475 for anything more complex than just a list of facts in canonical
  1476 order.
  1477 
  1478 * Isar: command 'declaration' augments a local theory by generic
  1479 declaration functions written in ML.  This enables arbitrary content
  1480 being added to the context, depending on a morphism that tells the
  1481 difference of the original declaration context wrt. the application
  1482 context encountered later on.
  1483 
  1484 * Isar: proper interfaces for simplification procedures.  Command
  1485 'simproc_setup' declares named simprocs (with match patterns, and body
  1486 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1487 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1488 
  1489 * Isar: an extra pair of brackets around attribute declarations
  1490 abbreviates a theorem reference involving an internal dummy fact,
  1491 which will be ignored later --- only the effect of the attribute on
  1492 the background context will persist.  This form of in-place
  1493 declarations is particularly useful with commands like 'declare' and
  1494 'using', for example ``have A using [[simproc a]] by simp''.
  1495 
  1496 * Isar: method "assumption" (and implicit closing of subproofs) now
  1497 takes simple non-atomic goal assumptions into account: after applying
  1498 an assumption as a rule the resulting subgoals are solved by atomic
  1499 assumption steps.  This is particularly useful to finish 'obtain'
  1500 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1501 without referring to the original premise "!!x. P x ==> thesis" in the
  1502 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1503 more permissive.
  1504 
  1505 * Isar: implicit use of prems from the Isar proof context is
  1506 considered a legacy feature.  Common applications like ``have A .''
  1507 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1508 referencing facts explicitly here improves readability and
  1509 maintainability of proof texts.
  1510 
  1511 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1512 the obtained context from the course of reasoning!  For example:
  1513 
  1514   assume "EX x y. A x & B y"   -- "any previous fact"
  1515   then guess x and y by clarify
  1516 
  1517 This technique is potentially adventurous, depending on the facts and
  1518 proof tools being involved here.
  1519 
  1520 * Isar: known facts from the proof context may be specified as literal
  1521 propositions, using ASCII back-quote syntax.  This works wherever
  1522 named facts used to be allowed so far, in proof commands, proof
  1523 methods, attributes etc.  Literal facts are retrieved from the context
  1524 according to unification of type and term parameters.  For example,
  1525 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1526 theorems in the current context, then these are valid literal facts:
  1527 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1528 
  1529 There is also a proof method "fact" which does the same composition
  1530 for explicit goal states, e.g. the following proof texts coincide with
  1531 certain special cases of literal facts:
  1532 
  1533   have "A" by fact                 ==  note `A`
  1534   have "A ==> B" by fact           ==  note `A ==> B`
  1535   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1536   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1537 
  1538 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1539 outer syntax.  Thus symbolic identifiers may be used without
  1540 additional white space in declarations like this: ``assume *: A''.
  1541 
  1542 * Isar: 'print_facts' prints all local facts of the current context,
  1543 both named and unnamed ones.
  1544 
  1545 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1546 
  1547   def x == "t" and y == "u"
  1548 
  1549 * Isar: added command 'unfolding', which is structurally similar to
  1550 'using', but affects both the goal state and facts by unfolding given
  1551 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1552 'unfolded' attribute may be replaced by first-class proof text.
  1553 
  1554 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1555 and command 'unfolding' now all support object-level equalities
  1556 (potentially conditional).  The underlying notion of rewrite rule is
  1557 analogous to the 'rule_format' attribute, but *not* that of the
  1558 Simplifier (which is usually more generous).
  1559 
  1560 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1561 premises of a theorem by n. Useful in conjunction with drule.
  1562 
  1563 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1564 method expression within a sandbox consisting of the first N
  1565 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1566 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1567 simplifies all new goals that emerge from applying rule foo to the
  1568 originally first one.
  1569 
  1570 * Isar: schematic goals are no longer restricted to higher-order
  1571 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1572 expected.
  1573 
  1574 * Isar: the conclusion of a long theorem statement is now either
  1575 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1576 (essentially a disjunction of cases with local parameters and
  1577 assumptions).  The latter allows to express general elimination rules
  1578 adequately; in this notation common elimination rules look like this:
  1579 
  1580   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1581     assumes "EX x. P x"
  1582     obtains x where "P x"
  1583 
  1584   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1585     assumes "A & B"
  1586     obtains A and B
  1587 
  1588   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1589     assumes "A | B"
  1590     obtains
  1591       A
  1592     | B
  1593 
  1594 The subsequent classical rules even refer to the formal "thesis"
  1595 explicitly:
  1596 
  1597   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1598     obtains "~ thesis"
  1599 
  1600   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1601     obtains "thesis ==> something"
  1602 
  1603 The actual proof of an 'obtains' statement is analogous to that of the
  1604 Isar proof element 'obtain', only that there may be several cases.
  1605 Optional case names may be specified in parentheses; these will be
  1606 available both in the present proof and as annotations in the
  1607 resulting rule, for later use with the 'cases' method (cf. attribute
  1608 case_names).
  1609 
  1610 * Isar: the assumptions of a long theorem statement are available as
  1611 "assms" fact in the proof context.  This is more appropriate than the
  1612 (historical) "prems", which refers to all assumptions of the current
  1613 context, including those from the target locale, proof body etc.
  1614 
  1615 * Isar: 'print_statement' prints theorems from the current theory or
  1616 proof context in long statement form, according to the syntax of a
  1617 top-level lemma.
  1618 
  1619 * Isar: 'obtain' takes an optional case name for the local context
  1620 introduction rule (default "that").
  1621 
  1622 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1623 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1624 to occur.
  1625 
  1626 * Pure: syntax "CONST name" produces a fully internalized constant
  1627 according to the current context.  This is particularly useful for
  1628 syntax translations that should refer to internal constant
  1629 representations independently of name spaces.
  1630 
  1631 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1632 instead of "FOO ". This allows multiple binder declarations to coexist
  1633 in the same context.  INCOMPATIBILITY.
  1634 
  1635 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1636 primitive that also works in a locale context (both for constants and
  1637 fixed variables). Type declaration and internal syntactic representation
  1638 of given constants retrieved from the context. Likewise, the
  1639 'no_notation' command allows to remove given syntax annotations from the
  1640 current context.
  1641 
  1642 * Isar/locales: new derived specification elements 'axiomatization',
  1643 'definition', 'abbreviation', which support type-inference, admit
  1644 object-level specifications (equality, equivalence).  See also the
  1645 isar-ref manual.  Examples:
  1646 
  1647   axiomatization
  1648     eq  (infix "===" 50) where
  1649     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1650 
  1651   definition "f x y = x + y + 1"
  1652   definition g where "g x = f x x"
  1653 
  1654   abbreviation
  1655     neq  (infix "=!=" 50) where
  1656     "x =!= y == ~ (x === y)"
  1657 
  1658 These specifications may be also used in a locale context.  Then the
  1659 constants being introduced depend on certain fixed parameters, and the
  1660 constant name is qualified by the locale base name.  An internal
  1661 abbreviation takes care for convenient input and output, making the
  1662 parameters implicit and using the original short name.  See also
  1663 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1664 entities from a monomorphic theory.
  1665 
  1666 Presently, abbreviations are only available 'in' a target locale, but
  1667 not inherited by general import expressions.  Also note that
  1668 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1669 'translations' in common applications.  The "no_abbrevs" print mode
  1670 prevents folding of abbreviations in term output.
  1671 
  1672 Concrete syntax is attached to specified constants in internal form,
  1673 independently of name spaces.  The parse tree representation is
  1674 slightly different -- use 'notation' instead of raw 'syntax', and
  1675 'translations' with explicit "CONST" markup to accommodate this.
  1676 
  1677 * Pure/Isar: unified syntax for new-style specification mechanisms
  1678 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1679 full type inference and dummy patterns ("_").  For example:
  1680 
  1681   definition "K x _ = x"
  1682 
  1683   inductive conj for A B
  1684   where "A ==> B ==> conj A B"
  1685 
  1686 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1687 the current context.  Print mode "no_abbrevs" prevents inversion of
  1688 abbreviations on output.
  1689 
  1690 * Isar/locales: improved parameter handling: use of locales "var" and
  1691 "struct" no longer necessary; - parameter renamings are no longer
  1692 required to be injective.  For example, this allows to define
  1693 endomorphisms as locale endom = homom mult mult h.
  1694 
  1695 * Isar/locales: changed the way locales with predicates are defined.
  1696 Instead of accumulating the specification, the imported expression is
  1697 now an interpretation.  INCOMPATIBILITY: different normal form of
  1698 locale expressions.  In particular, in interpretations of locales with
  1699 predicates, goals repesenting already interpreted fragments are not
  1700 removed automatically.  Use methods `intro_locales' and
  1701 `unfold_locales'; see below.
  1702 
  1703 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1704 provide backward reasoning on locales predicates.  The methods are
  1705 aware of interpretations and discharge corresponding goals.
  1706 `intro_locales' is less aggressive then `unfold_locales' and does not
  1707 unfold predicates to assumptions.
  1708 
  1709 * Isar/locales: the order in which locale fragments are accumulated
  1710 has changed.  This enables to override declarations from fragments due
  1711 to interpretations -- for example, unwanted simp rules.
  1712 
  1713 * Isar/locales: interpretation in theories and proof contexts has been
  1714 extended.  One may now specify (and prove) equations, which are
  1715 unfolded in interpreted theorems.  This is useful for replacing
  1716 defined concepts (constants depending on locale parameters) by
  1717 concepts already existing in the target context.  Example:
  1718 
  1719   interpretation partial_order ["op <= :: [int, int] => bool"]
  1720     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1721 
  1722 Typically, the constant `partial_order.less' is created by a
  1723 definition specification element in the context of locale
  1724 partial_order.
  1725 
  1726 * Method "induct": improved internal context management to support
  1727 local fixes and defines on-the-fly. Thus explicit meta-level
  1728 connectives !!  and ==> are rarely required anymore in inductive goals
  1729 (using object-logic connectives for this purpose has been long
  1730 obsolete anyway). Common proof patterns are explained in
  1731 src/HOL/Induct/Common_Patterns.thy, see also
  1732 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1733 examples.
  1734 
  1735 * Method "induct": improved handling of simultaneous goals. Instead of
  1736 introducing object-level conjunction, the statement is now split into
  1737 several conclusions, while the corresponding symbolic cases are nested
  1738 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1739 see src/HOL/Induct/Common_Patterns.thy, for example.
  1740 
  1741 * Method "induct": mutual induction rules are now specified as a list
  1742 of rule sharing the same induction cases. HOL packages usually provide
  1743 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1744 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1745 mutual induction rules differently, i.e. like this:
  1746 
  1747   (induct rule: foo_bar.inducts)
  1748   (induct set: foo bar)
  1749   (induct pred: foo bar)
  1750   (induct type: foo bar)
  1751 
  1752 The ML function ProjectRule.projections turns old-style rules into the
  1753 new format.
  1754 
  1755 * Method "coinduct": dual of induction, see
  1756 src/HOL/Library/Coinductive_List.thy for various examples.
  1757 
  1758 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1759 considered a legacy feature.
  1760 
  1761 * Attribute "symmetric" produces result with standardized schematic
  1762 variables (index 0).  Potential INCOMPATIBILITY.
  1763 
  1764 * Simplifier: by default the simplifier trace only shows top level
  1765 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1766 default. Thus there is less danger of being flooded by the trace. The
  1767 trace indicates where parts have been suppressed.
  1768   
  1769 * Provers/classical: removed obsolete classical version of elim_format
  1770 attribute; classical elim/dest rules are now treated uniformly when
  1771 manipulating the claset.
  1772 
  1773 * Provers/classical: stricter checks to ensure that supplied intro,
  1774 dest and elim rules are well-formed; dest and elim rules must have at
  1775 least one premise.
  1776 
  1777 * Provers/classical: attributes dest/elim/intro take an optional
  1778 weight argument for the rule (just as the Pure versions).  Weights are
  1779 ignored by automated tools, but determine the search order of single
  1780 rule steps.
  1781 
  1782 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1783 where the body does not mention the bound variable.  Note that dummy
  1784 patterns implicitly depend on their context of bounds, which makes
  1785 "{_. _}" match any set comprehension as expected.  Potential
  1786 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1787 constant "_idtdummy" in the binding position.
  1788 
  1789 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1790 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1791 for example "A -> B" => "Pi A (%_. B)".
  1792 
  1793 * Pure: 'class_deps' command visualizes the subclass relation, using
  1794 the graph browser tool.
  1795 
  1796 * Pure: 'print_theory' now suppresses certain internal declarations by
  1797 default; use '!' option for full details.
  1798 
  1799 
  1800 *** HOL ***
  1801 
  1802 * Method "metis" proves goals by applying the Metis general-purpose
  1803 resolution prover (see also http://gilith.com/software/metis/).
  1804 Examples are in the directory MetisExamples.  WARNING: the
  1805 Isabelle/HOL-Metis integration does not yet work properly with
  1806 multi-threading.
  1807   
  1808 * Command 'sledgehammer' invokes external automatic theorem provers as
  1809 background processes.  It generates calls to the "metis" method if
  1810 successful. These can be pasted into the proof.  Users do not have to
  1811 wait for the automatic provers to return.  WARNING: does not really
  1812 work with multi-threading.
  1813 
  1814 * New "auto_quickcheck" feature tests outermost goal statements for
  1815 potential counter-examples.  Controlled by ML references
  1816 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1817 5000 milliseconds).  Fails silently if statements is outside of
  1818 executable fragment, or any other codgenerator problem occurs.
  1819 
  1820 * New constant "undefined" with axiom "undefined x = undefined".
  1821 
  1822 * Added class "HOL.eq", allowing for code generation with polymorphic
  1823 equality.
  1824 
  1825 * Some renaming of class constants due to canonical name prefixing in
  1826 the new 'class' package:
  1827 
  1828     HOL.abs ~> HOL.abs_class.abs
  1829     HOL.divide ~> HOL.divide_class.divide
  1830     0 ~> HOL.zero_class.zero
  1831     1 ~> HOL.one_class.one
  1832     op + ~> HOL.plus_class.plus
  1833     op - ~> HOL.minus_class.minus
  1834     uminus ~> HOL.minus_class.uminus
  1835     op * ~> HOL.times_class.times
  1836     op < ~> HOL.ord_class.less
  1837     op <= > HOL.ord_class.less_eq
  1838     Nat.power ~> Power.power_class.power
  1839     Nat.size ~> Nat.size_class.size
  1840     Numeral.number_of ~> Numeral.number_class.number_of
  1841     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1842     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1843     Orderings.min ~> Orderings.ord_class.min
  1844     Orderings.max ~> Orderings.ord_class.max
  1845     Divides.op div ~> Divides.div_class.div
  1846     Divides.op mod ~> Divides.div_class.mod
  1847     Divides.op dvd ~> Divides.div_class.dvd
  1848 
  1849 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1850 
  1851 a) User-defined constants using any of the names "plus", "minus",
  1852 "times", "less" or "less_eq". The standard syntax translations for
  1853 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1854 names.
  1855 
  1856 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1857 INCOMPATIBILITY: use more specific names.
  1858 
  1859 c) Permutative equations (e.g. "a + b = b + a")
  1860 Since the change of names also changes the order of terms, permutative
  1861 rewrite rules may get applied in a different order. Experience shows
  1862 that this is rarely the case (only two adaptions in the whole Isabelle
  1863 distribution).  INCOMPATIBILITY: rewrite proofs
  1864 
  1865 d) ML code directly refering to constant names
  1866 This in general only affects hand-written proof tactics, simprocs and
  1867 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1868 Consider using @{const_name} antiquotation.
  1869 
  1870 * New class "default" with associated constant "default".
  1871 
  1872 * Function "sgn" is now overloaded and available on int, real, complex
  1873 (and other numeric types), using class "sgn".  Two possible defs of
  1874 sgn are given as equational assumptions in the classes sgn_if and
  1875 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1876 INCOMPATIBILITY.
  1877 
  1878 * Locale "partial_order" now unified with class "order" (cf. theory
  1879 Orderings), added parameter "less".  INCOMPATIBILITY.
  1880 
  1881 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1882 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1883 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1884 
  1885 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1886 changed order of proof goals in instance proofs.
  1887 
  1888 * The transitivity reasoner for partial and linear orders is set up
  1889 for classes "order" and "linorder".  Instances of the reasoner are available
  1890 in all contexts importing or interpreting the corresponding locales.
  1891 Method "order" invokes the reasoner separately; the reasoner
  1892 is also integrated with the Simplifier as a solver.  Diagnostic
  1893 command 'print_orders' shows the available instances of the reasoner
  1894 in the current context.
  1895 
  1896 * Localized monotonicity predicate in theory "Orderings"; integrated
  1897 lemmas max_of_mono and min_of_mono with this predicate.
  1898 INCOMPATIBILITY.
  1899 
  1900 * Formulation of theorem "dense" changed slightly due to integration
  1901 with new class dense_linear_order.
  1902 
  1903 * Uniform lattice theory development in HOL.
  1904 
  1905     constants "meet" and "join" now named "inf" and "sup"
  1906     constant "Meet" now named "Inf"
  1907 
  1908     classes "meet_semilorder" and "join_semilorder" now named
  1909       "lower_semilattice" and "upper_semilattice"
  1910     class "lorder" now named "lattice"
  1911     class "comp_lat" now named "complete_lattice"
  1912 
  1913     Instantiation of lattice classes allows explicit definitions
  1914     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1915 
  1916   INCOMPATIBILITY.  Theorem renames:
  1917 
  1918     meet_left_le            ~> inf_le1
  1919     meet_right_le           ~> inf_le2
  1920     join_left_le            ~> sup_ge1
  1921     join_right_le           ~> sup_ge2
  1922     meet_join_le            ~> inf_sup_ord
  1923     le_meetI                ~> le_infI
  1924     join_leI                ~> le_supI
  1925     le_meet                 ~> le_inf_iff
  1926     le_join                 ~> ge_sup_conv
  1927     meet_idempotent         ~> inf_idem
  1928     join_idempotent         ~> sup_idem
  1929     meet_comm               ~> inf_commute
  1930     join_comm               ~> sup_commute
  1931     meet_leI1               ~> le_infI1
  1932     meet_leI2               ~> le_infI2
  1933     le_joinI1               ~> le_supI1
  1934     le_joinI2               ~> le_supI2
  1935     meet_assoc              ~> inf_assoc
  1936     join_assoc              ~> sup_assoc
  1937     meet_left_comm          ~> inf_left_commute
  1938     meet_left_idempotent    ~> inf_left_idem
  1939     join_left_comm          ~> sup_left_commute
  1940     join_left_idempotent    ~> sup_left_idem
  1941     meet_aci                ~> inf_aci
  1942     join_aci                ~> sup_aci
  1943     le_def_meet             ~> le_iff_inf
  1944     le_def_join             ~> le_iff_sup
  1945     join_absorp2            ~> sup_absorb2
  1946     join_absorp1            ~> sup_absorb1
  1947     meet_absorp1            ~> inf_absorb1
  1948     meet_absorp2            ~> inf_absorb2
  1949     meet_join_absorp        ~> inf_sup_absorb
  1950     join_meet_absorp        ~> sup_inf_absorb
  1951     distrib_join_le         ~> distrib_sup_le
  1952     distrib_meet_le         ~> distrib_inf_le
  1953 
  1954     add_meet_distrib_left   ~> add_inf_distrib_left
  1955     add_join_distrib_left   ~> add_sup_distrib_left
  1956     is_join_neg_meet        ~> is_join_neg_inf
  1957     is_meet_neg_join        ~> is_meet_neg_sup
  1958     add_meet_distrib_right  ~> add_inf_distrib_right
  1959     add_join_distrib_right  ~> add_sup_distrib_right
  1960     add_meet_join_distribs  ~> add_sup_inf_distribs
  1961     join_eq_neg_meet        ~> sup_eq_neg_inf
  1962     meet_eq_neg_join        ~> inf_eq_neg_sup
  1963     add_eq_meet_join        ~> add_eq_inf_sup
  1964     meet_0_imp_0            ~> inf_0_imp_0
  1965     join_0_imp_0            ~> sup_0_imp_0
  1966     meet_0_eq_0             ~> inf_0_eq_0
  1967     join_0_eq_0             ~> sup_0_eq_0
  1968     neg_meet_eq_join        ~> neg_inf_eq_sup
  1969     neg_join_eq_meet        ~> neg_sup_eq_inf
  1970     join_eq_if              ~> sup_eq_if
  1971 
  1972     mono_meet               ~> mono_inf
  1973     mono_join               ~> mono_sup
  1974     meet_bool_eq            ~> inf_bool_eq
  1975     join_bool_eq            ~> sup_bool_eq
  1976     meet_fun_eq             ~> inf_fun_eq
  1977     join_fun_eq             ~> sup_fun_eq
  1978     meet_set_eq             ~> inf_set_eq
  1979     join_set_eq             ~> sup_set_eq
  1980     meet1_iff               ~> inf1_iff
  1981     meet2_iff               ~> inf2_iff
  1982     meet1I                  ~> inf1I
  1983     meet2I                  ~> inf2I
  1984     meet1D1                 ~> inf1D1
  1985     meet2D1                 ~> inf2D1
  1986     meet1D2                 ~> inf1D2
  1987     meet2D2                 ~> inf2D2
  1988     meet1E                  ~> inf1E
  1989     meet2E                  ~> inf2E
  1990     join1_iff               ~> sup1_iff
  1991     join2_iff               ~> sup2_iff
  1992     join1I1                 ~> sup1I1
  1993     join2I1                 ~> sup2I1
  1994     join1I1                 ~> sup1I1
  1995     join2I2                 ~> sup1I2
  1996     join1CI                 ~> sup1CI
  1997     join2CI                 ~> sup2CI
  1998     join1E                  ~> sup1E
  1999     join2E                  ~> sup2E
  2000 
  2001     is_meet_Meet            ~> is_meet_Inf
  2002     Meet_bool_def           ~> Inf_bool_def
  2003     Meet_fun_def            ~> Inf_fun_def
  2004     Meet_greatest           ~> Inf_greatest
  2005     Meet_lower              ~> Inf_lower
  2006     Meet_set_def            ~> Inf_set_def
  2007 
  2008     Sup_def                 ~> Sup_Inf
  2009     Sup_bool_eq             ~> Sup_bool_def
  2010     Sup_fun_eq              ~> Sup_fun_def
  2011     Sup_set_eq              ~> Sup_set_def
  2012 
  2013     listsp_meetI            ~> listsp_infI
  2014     listsp_meet_eq          ~> listsp_inf_eq
  2015 
  2016     meet_min                ~> inf_min
  2017     join_max                ~> sup_max
  2018 
  2019 * Added syntactic class "size"; overloaded constant "size" now has
  2020 type "'a::size ==> bool"
  2021 
  2022 * Internal reorganisation of `size' of datatypes: size theorems
  2023 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2024 simplification rules by default!); theorems "prod.size" now named
  2025 "*.size".
  2026 
  2027 * Class "div" now inherits from class "times" rather than "type".
  2028 INCOMPATIBILITY.
  2029 
  2030 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2031 Linorder etc.  have disappeared; operations defined in terms of
  2032 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2033 
  2034 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2035 
  2036 * HOL-Word: New extensive library and type for generic, fixed size
  2037 machine words, with arithemtic, bit-wise, shifting and rotating
  2038 operations, reflection into int, nat, and bool lists, automation for
  2039 linear arithmetic (by automatic reflection into nat or int), including
  2040 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2041 arithmetic type classes, supporting automatic simplification of
  2042 numerals on all operations.
  2043 
  2044 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2045 
  2046 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2047 
  2048 * Code generator library theories:
  2049   - Code_Integer represents HOL integers by big integer literals in target
  2050     languages.
  2051   - Code_Char represents HOL characters by character literals in target
  2052     languages.
  2053   - Code_Char_chr like Code_Char, but also offers treatment of character
  2054     codes; includes Code_Integer.
  2055   - Executable_Set allows to generate code for finite sets using lists.
  2056   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2057     denominator).
  2058   - Executable_Real implements a subset of real numbers, namly those
  2059     representable by rational numbers.
  2060   - Efficient_Nat implements natural numbers by integers, which in general will
  2061     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2062     includes Code_Integer.
  2063   - Code_Index provides an additional datatype index which is mapped to
  2064     target-language built-in integers.
  2065   - Code_Message provides an additional datatype message_string which is isomorphic to
  2066     strings; messages are mapped to target-language strings.
  2067 
  2068 * New package for inductive predicates
  2069 
  2070   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2071 
  2072     inductive
  2073       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2074       for z_1 :: U_1 and ... and z_n :: U_m
  2075     where
  2076       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2077     | ...
  2078 
  2079   with full support for type-inference, rather than
  2080 
  2081     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2082 
  2083     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2084     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2085 
  2086     inductive "s z_1 ... z_m"
  2087     intros
  2088       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2089       ...
  2090 
  2091   For backward compatibility, there is a wrapper allowing inductive
  2092   sets to be defined with the new package via
  2093 
  2094     inductive_set
  2095       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2096       for z_1 :: U_1 and ... and z_n :: U_m
  2097     where
  2098       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2099     | ...
  2100 
  2101   or
  2102 
  2103     inductive_set
  2104       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2105       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2106       for z_1 :: U_1 and ... and z_n :: U_m
  2107     where
  2108       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2109     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2110     | ...
  2111 
  2112   if the additional syntax "p ..." is required.
  2113 
  2114   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2115   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2116 
  2117   INCOMPATIBILITIES:
  2118 
  2119   - Since declaration and definition of inductive sets or predicates
  2120     is no longer separated, abbreviations involving the newly
  2121     introduced sets or predicates must be specified together with the
  2122     introduction rules after the 'where' keyword (see above), rather
  2123     than before the actual inductive definition.
  2124 
  2125   - The variables in induction and elimination rules are now
  2126     quantified in the order of their occurrence in the introduction
  2127     rules, rather than in alphabetical order. Since this may break
  2128     some proofs, these proofs either have to be repaired, e.g. by
  2129     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2130     statements of the form
  2131 
  2132       case (rule_i a_i_1 ... a_i_{k_i})
  2133 
  2134     or the old order of quantification has to be restored by explicitly adding
  2135     meta-level quantifiers in the introduction rules, i.e.
  2136 
  2137       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2138 
  2139   - The format of the elimination rules is now
  2140 
  2141       p z_1 ... z_m x_1 ... x_n ==>
  2142         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2143         ==> ... ==> P
  2144 
  2145     for predicates and
  2146 
  2147       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2148         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2149         ==> ... ==> P
  2150 
  2151     for sets rather than
  2152 
  2153       x : s z_1 ... z_m ==>
  2154         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2155         ==> ... ==> P
  2156 
  2157     This may require terms in goals to be expanded to n-tuples
  2158     (e.g. using case_tac or simplification with the split_paired_all
  2159     rule) before the above elimination rule is applicable.
  2160 
  2161   - The elimination or case analysis rules for (mutually) inductive
  2162     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2163     list of rules "p_1_..._p_k.elims" is no longer available.
  2164 
  2165 * New package "function"/"fun" for general recursive functions,
  2166 supporting mutual and nested recursion, definitions in local contexts,
  2167 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2168 for small examples, and the separate tutorial on the function
  2169 package. The old recdef "package" is still available as before, but
  2170 users are encouraged to use the new package.
  2171 
  2172 * Method "lexicographic_order" automatically synthesizes termination
  2173 relations as lexicographic combinations of size measures. 
  2174 
  2175 * Case-expressions allow arbitrary constructor-patterns (including
  2176 "_") and take their order into account, like in functional
  2177 programming.  Internally, this is translated into nested
  2178 case-expressions; missing cases are added and mapped to the predefined
  2179 constant "undefined". In complicated cases printing may no longer show
  2180 the original input but the internal form. Lambda-abstractions allow
  2181 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2182 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2183 variable.
  2184 
  2185 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2186 is an abbreviation for "of_nat :: nat => int". The simplification
  2187 rules for "of_nat" have been changed to work like "int" did
  2188 previously.  Potential INCOMPATIBILITY:
  2189   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2190   - of_nat_diff and of_nat_mult are no longer default simp rules
  2191 
  2192 * Method "algebra" solves polynomial equations over (semi)rings using
  2193 Groebner bases. The (semi)ring structure is defined by locales and the
  2194 tool setup depends on that generic context. Installing the method for
  2195 a specific type involves instantiating the locale and possibly adding
  2196 declarations for computation on the coefficients.  The method is
  2197 already instantiated for natural numbers and for the axiomatic class
  2198 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2199 CALCULEMUS 2007 for the general principles underlying this
  2200 architecture of context-aware proof-tools.
  2201 
  2202 * Method "ferrack" implements quantifier elimination over
  2203 special-purpose dense linear orders using locales (analogous to
  2204 "algebra"). The method is already installed for class
  2205 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2206 rat, etc.
  2207 
  2208 * Former constant "List.op @" now named "List.append".  Use ML
  2209 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2210 circumvent possible incompatibilities when working on ML level.
  2211 
  2212 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2213 
  2214 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2215 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2216 
  2217 * New syntax for Haskell-like list comprehension (input only), eg.
  2218 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2219 
  2220 * The special syntax for function "filter" has changed from [x :
  2221 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2222 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2223 
  2224 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2225 defined on nat only, as an abbreviation for [a..<Suc b]
  2226 INCOMPATIBILITY.
  2227 
  2228 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2229 
  2230 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2231 
  2232 * New lemma collection field_simps (an extension of ring_simps) for
  2233 manipulating (in)equations involving division. Multiplies with all
  2234 denominators that can be proved to be non-zero (in equations) or
  2235 positive/negative (in inequations).
  2236 
  2237 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2238 have been improved and renamed to ring_simps, group_simps and
  2239 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2240 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2241 
  2242 * Theory Library/Commutative_Ring: switched from recdef to function
  2243 package; constants add, mul, pow now curried.  Infix syntax for
  2244 algebraic operations.
  2245 
  2246 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2247 INCOMPATIBILITY.
  2248 
  2249 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2250 INCOMPATIBILITY.
  2251 
  2252 * HOL/records: generalised field-update to take a function on the
  2253 field rather than the new value: r(|A := x|) is translated to A_update
  2254 (K x) r The K-combinator that is internally used is called K_record.
  2255 INCOMPATIBILITY: Usage of the plain update functions has to be
  2256 adapted.
  2257  
  2258 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2259 * x = 0, which are required for a semiring.  Richer structures do not
  2260 inherit from semiring_0 anymore, because this property is a theorem
  2261 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2262 there is more to prove, but this is mostly trivial.
  2263 
  2264 * Class "recpower" is generalized to arbitrary monoids, not just
  2265 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2266 commutativity or semiring properties additionally.
  2267 
  2268 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2269 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2270 better use 'abbreviation'.
  2271 
  2272 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2273 
  2274 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2275 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2276 significant changes for setting up numeral syntax for types:
  2277   - New constants Numeral.pred and Numeral.succ instead
  2278       of former Numeral.bin_pred and Numeral.bin_succ.
  2279   - Use integer operations instead of bin_add, bin_mult and so on.
  2280   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2281   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2282 
  2283 See src/HOL/Integ/IntArith.thy for an example setup.
  2284 
  2285 * Command 'normal_form' computes the normal form of a term that may
  2286 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2287 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2288 heavy-duty computations because the functions are compiled to ML
  2289 first.  Correspondingly, a method "normalization" is provided.  See
  2290 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2291 
  2292 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2293 25 like -->); output depends on the "iff" print_mode, the default is
  2294 "A = B" (with priority 50).
  2295 
  2296 * Relations less (<) and less_eq (<=) are also available on type bool.
  2297 Modified syntax to disallow nesting without explicit parentheses,
  2298 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2299 INCOMPATIBILITY.
  2300 
  2301 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2302 
  2303 * Relation composition operator "op O" now has precedence 75 and binds
  2304 stronger than union and intersection. INCOMPATIBILITY.
  2305 
  2306 * The old set interval syntax "{m..n(}" (and relatives) has been
  2307 removed.  Use "{m..<n}" (and relatives) instead.
  2308 
  2309 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2310 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2311 ``declare [[simproc del: neq]]''.
  2312 
  2313 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2314 True/False.
  2315 
  2316 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2317 
  2318 * Theorem setsum_mult renamed to setsum_right_distrib.
  2319 
  2320 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2321 ``rule'' method.
  2322 
  2323 * Reimplemented methods "sat" and "satx", with several improvements:
  2324 goals no longer need to be stated as "<prems> ==> False", equivalences
  2325 (i.e. "=" on type bool) are handled, variable names of the form
  2326 "lit_<n>" are no longer reserved, significant speedup.
  2327 
  2328 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2329 zChaff is still supported as well.
  2330 
  2331 * 'inductive' and 'datatype': provide projections of mutual rules,
  2332 bundled as foo_bar.inducts;
  2333 
  2334 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2335 Library.
  2336 
  2337 * Library: moved theory Accessible_Part to main HOL.
  2338 
  2339 * Library: added theory Coinductive_List of potentially infinite lists
  2340 as greatest fixed-point.
  2341 
  2342 * Library: added theory AssocList which implements (finite) maps as
  2343 association lists.
  2344 
  2345 * Method "evaluation" solves goals (i.e. a boolean expression)
  2346 efficiently by compiling it to ML.  The goal is "proved" (via an
  2347 oracle) if it evaluates to True.
  2348 
  2349 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2350 also when invoked by the simplifier.  This results in the Simplifier
  2351 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2352 Configuration option fast_arith_split_limit=0 recovers the old
  2353 behavior.
  2354 
  2355 * Support for hex (0x20) and binary (0b1001) numerals.
  2356 
  2357 * New method: reify eqs (t), where eqs are equations for an
  2358 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2359 parameter, computes a term s::'b and a list xs::'a list and proves the
  2360 theorem I xs s = t. This is also known as reification or quoting. The
  2361 resulting theorem is applied to the subgoal to substitute t with I xs
  2362 s.  If t is omitted, the subgoal itself is reified.
  2363 
  2364 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2365 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2366 where f is supposed to be a computable function (in the sense of code
  2367 generattion). The method uses reify to compute s and xs as above then
  2368 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2369 r and finally gets the theorem t = r, which is again applied to the
  2370 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2371 
  2372 * Reflection: Automatic reification now handels binding, an example is
  2373 available in src/HOL/ex/ReflectionEx.thy
  2374 
  2375 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2376 command 'statespace' that is similar to 'record', but introduces an
  2377 abstract specification based on the locale infrastructure instead of
  2378 HOL types.  This leads to extra flexibility in composing state spaces,
  2379 in particular multiple inheritance and renaming of components.
  2380 
  2381 
  2382 *** HOL-Complex ***
  2383 
  2384 * Hyperreal: Functions root and sqrt are now defined on negative real
  2385 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2386 Nonnegativity side conditions have been removed from many lemmas, so
  2387 that more subgoals may now be solved by simplification; potential
  2388 INCOMPATIBILITY.
  2389 
  2390 * Real: new type classes formalize real normed vector spaces and
  2391 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2392 and norm :: 'a => real.
  2393 
  2394 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2395 reals into other types. The overloaded constant Reals :: 'a set is now
  2396 defined as range of_real; potential INCOMPATIBILITY.
  2397 
  2398 * Real: proper support for ML code generation, including 'quickcheck'.
  2399 Reals are implemented as arbitrary precision rationals.
  2400 
  2401 * Hyperreal: Several constants that previously worked only for the
  2402 reals have been generalized, so they now work over arbitrary vector
  2403 spaces. Type annotations may need to be added in some cases; potential
  2404 INCOMPATIBILITY.
  2405 
  2406   Infinitesimal  :: ('a::real_normed_vector) star set
  2407   HFinite        :: ('a::real_normed_vector) star set
  2408   HInfinite      :: ('a::real_normed_vector) star set
  2409   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2410   monad          :: ('a::real_normed_vector) star => 'a star set
  2411   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2412   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2413   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2414   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2415   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2416   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2417   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2418   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2419   sgn            :: 'a::real_normed_vector => 'a
  2420   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2421 
  2422 * Complex: Some complex-specific constants are now abbreviations for
  2423 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2424 hnorm.  Other constants have been entirely removed in favor of the
  2425 polymorphic versions (INCOMPATIBILITY):
  2426 
  2427   approx        <-- capprox
  2428   HFinite       <-- CFinite
  2429   HInfinite     <-- CInfinite
  2430   Infinitesimal <-- CInfinitesimal
  2431   monad         <-- cmonad
  2432   galaxy        <-- cgalaxy
  2433   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2434   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2435   (ns)deriv     <-- (ns)cderiv
  2436 
  2437 
  2438 *** HOL-Algebra ***
  2439 
  2440 * Formalisation of ideals and the quotient construction over rings.
  2441 
  2442 * Order and lattice theory no longer based on records.
  2443 INCOMPATIBILITY.
  2444 
  2445 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2446 greatest_closed.  INCOMPATIBILITY.
  2447 
  2448 * Method algebra is now set up via an attribute.  For examples see
  2449 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2450 of algebraic structures.
  2451 
  2452 * Renamed theory CRing to Ring.
  2453 
  2454 
  2455 *** HOL-Nominal ***
  2456 
  2457 * Substantial, yet incomplete support for nominal datatypes (binding
  2458 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2459 src/HOL/Nominal/Examples.  Prospective users should consult
  2460 http://isabelle.in.tum.de/nominal/
  2461 
  2462 
  2463 *** ML ***
  2464 
  2465 * ML basics: just one true type int, which coincides with IntInf.int
  2466 (even on SML/NJ).
  2467 
  2468 * ML within Isar: antiquotations allow to embed statically-checked
  2469 formal entities in the source, referring to the context available at
  2470 compile-time.  For example:
  2471 
  2472 ML {* @{sort "{zero,one}"} *}
  2473 ML {* @{typ "'a => 'b"} *}
  2474 ML {* @{term "%x. x"} *}
  2475 ML {* @{prop "x == y"} *}
  2476 ML {* @{ctyp "'a => 'b"} *}
  2477 ML {* @{cterm "%x. x"} *}
  2478 ML {* @{cprop "x == y"} *}
  2479 ML {* @{thm asm_rl} *}
  2480 ML {* @{thms asm_rl} *}
  2481 ML {* @{type_name c} *}
  2482 ML {* @{type_syntax c} *}
  2483 ML {* @{const_name c} *}
  2484 ML {* @{const_syntax c} *}
  2485 ML {* @{context} *}
  2486 ML {* @{theory} *}
  2487 ML {* @{theory Pure} *}
  2488 ML {* @{theory_ref} *}
  2489 ML {* @{theory_ref Pure} *}
  2490 ML {* @{simpset} *}
  2491 ML {* @{claset} *}
  2492 ML {* @{clasimpset} *}
  2493 
  2494 The same works for sources being ``used'' within an Isar context.
  2495 
  2496 * ML in Isar: improved error reporting; extra verbosity with
  2497 ML_Context.trace enabled.
  2498 
  2499 * Pure/General/table.ML: the join operations now works via exceptions
  2500 DUP/SAME instead of type option. This is simpler in simple cases, and
  2501 admits slightly more efficient complex applications.
  2502 
  2503 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2504 use Context.generic instead of just theory.
  2505 
  2506 * Pure: datatype Context.generic joins theory/Proof.context and
  2507 provides some facilities for code that works in either kind of
  2508 context, notably GenericDataFun for uniform theory and proof data.
  2509 
  2510 * Pure: simplified internal attribute type, which is now always
  2511 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2512 local (Proof.context) attributes have been discontinued, while
  2513 minimizing code duplication. Thm.rule_attribute and
  2514 Thm.declaration_attribute build canonical attributes; see also structure
  2515 Context for further operations on Context.generic, notably
  2516 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2517 declarations and definitions.
  2518 
  2519 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2520 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2521 init only required for impure data. INCOMPATIBILITY: empty really need
  2522 to be empty (no dependencies on theory content!)
  2523 
  2524 * Pure/kernel: consts certification ignores sort constraints given in
  2525 signature declarations. (This information is not relevant to the
  2526 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2527 potential INCOMPATIBILITY.
  2528 
  2529 * Pure: axiomatic type classes are now purely definitional, with
  2530 explicit proofs of class axioms and super class relations performed
  2531 internally. See Pure/axclass.ML for the main internal interfaces --
  2532 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2533 AxClass.axiomatize_class/classrel/arity supersede
  2534 Sign.add_classes/classrel/arities.
  2535 
  2536 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2537 global/local versions on theory vs. Proof.context have been
  2538 discontinued; Attrib.syntax and Method.syntax have been adapted
  2539 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2540 attributes, methods, etc.
  2541 
  2542 * Pure: several functions of signature "... -> theory -> theory * ..."
  2543 have been reoriented to "... -> theory -> ... * theory" in order to
  2544 allow natural usage in combination with the ||>, ||>>, |-> and
  2545 fold_map combinators.
  2546 
  2547 * Pure: official theorem names (closed derivations) and additional
  2548 comments (tags) are now strictly separate.  Name hints -- which are
  2549 maintained as tags -- may be attached any time without affecting the
  2550 derivation.
  2551 
  2552 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2553 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2554 achieve the old behaviour.
  2555 
  2556 * Pure: the "Goal" constant is now called "prop", supporting a
  2557 slightly more general idea of ``protecting'' meta-level rule
  2558 statements.
  2559 
  2560 * Pure: Logic.(un)varify only works in a global context, which is now
  2561 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2562 Logic.legacy_(un)varify as temporary workaround.
  2563 
  2564 * Pure: structure Name provides scalable operations for generating
  2565 internal variable names, notably Name.variants etc.  This replaces
  2566 some popular functions from term.ML:
  2567 
  2568   Term.variant		->  Name.variant
  2569   Term.variantlist	->  Name.variant_list
  2570   Term.invent_names	->  Name.invent_list
  2571 
  2572 Note that low-level renaming rarely occurs in new code -- operations
  2573 from structure Variable are used instead (see below).
  2574 
  2575 * Pure: structure Variable provides fundamental operations for proper
  2576 treatment of fixed/schematic variables in a context.  For example,
  2577 Variable.import introduces fixes for schematics of given facts and
  2578 Variable.export reverses the effect (up to renaming) -- this replaces
  2579 various freeze_thaw operations.
  2580 
  2581 * Pure: structure Goal provides simple interfaces for
  2582 init/conclude/finish and tactical prove operations (replacing former
  2583 Tactic.prove).  Goal.prove is the canonical way to prove results
  2584 within a given context; Goal.prove_global is a degraded version for
  2585 theory level goals, including a global Drule.standard.  Note that
  2586 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2587 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2588 in a locale context).
  2589 
  2590 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2591 and type checking (Syntax.check_term etc.), with common combinations
  2592 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2593 which are considered legacy and await removal.
  2594 
  2595 * Pure/Syntax: generic interfaces for type unchecking
  2596 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2597 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2598 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2599 available for convenience, but refer to the very same operations using
  2600 a mere theory instead of a full context.
  2601 
  2602 * Isar: simplified treatment of user-level errors, using exception
  2603 ERROR of string uniformly.  Function error now merely raises ERROR,
  2604 without any side effect on output channels.  The Isar toplevel takes
  2605 care of proper display of ERROR exceptions.  ML code may use plain
  2606 handle/can/try; cat_error may be used to concatenate errors like this:
  2607 
  2608   ... handle ERROR msg => cat_error msg "..."
  2609 
  2610 Toplevel ML code (run directly or through the Isar toplevel) may be
  2611 embedded into the Isar toplevel with exception display/debug like
  2612 this:
  2613 
  2614   Isar.toplevel (fn () => ...)
  2615 
  2616 INCOMPATIBILITY, removed special transform_error facilities, removed
  2617 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2618 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2619 -- use plain ERROR instead.
  2620 
  2621 * Isar: theory setup now has type (theory -> theory), instead of a
  2622 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2623 
  2624 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2625 ProofContext.debug/verbose flags.
  2626 
  2627 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2628 theory before entering a proof state.  Transactions now always see a
  2629 quasi-functional intermediate checkpoint, both in interactive and
  2630 batch mode.
  2631 
  2632 * Isar: simplified interfaces for outer syntax.  Renamed
  2633 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2634 OuterSyntax.add_parsers -- this functionality is now included in
  2635 OuterSyntax.command etc.  INCOMPATIBILITY.
  2636 
  2637 * Simplifier: the simpset of a running simplification process now
  2638 contains a proof context (cf. Simplifier.the_context), which is the
  2639 very context that the initial simpset has been retrieved from (by
  2640 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2641 (solver, looper etc.) may depend on arbitrary proof data.
  2642 
  2643 * Simplifier.inherit_context inherits the proof context (plus the
  2644 local bounds) of the current simplification process; any simproc
  2645 etc. that calls the Simplifier recursively should do this!  Removed
  2646 former Simplifier.inherit_bounds, which is already included here --
  2647 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2648 specify an explicit context using Simplifier.context/theory_context.
  2649 
  2650 * Simplifier/Classical Reasoner: more abstract interfaces
  2651 change_simpset/claset for modifying the simpset/claset reference of a
  2652 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2653 INCOMPATIBILITY.
  2654 
  2655 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2656 "Trueprop" etc.
  2657 
  2658 
  2659 *** System ***
  2660 
  2661 * settings: the default heap location within ISABELLE_HOME_USER now
  2662 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2663 Isabelle installations.
  2664 
  2665 * isabelle-process: option -S (secure mode) disables some critical
  2666 operations, notably runtime compilation and evaluation of ML source
  2667 code.
  2668 
  2669 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2670 
  2671 * Support for parallel execution, using native multicore support of
  2672 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2673 independent theories, according to the given theory header
  2674 specifications. The maximum number of worker threads is specified via
  2675 usedir option -M or the "max-threads" setting in Proof General. A
  2676 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2677 to 6 on a 8-core machine.  User-code needs to observe certain
  2678 guidelines for thread-safe programming, see appendix A in the Isar
  2679 Implementation manual.
  2680 
  2681 
  2682 
  2683 New in Isabelle2005 (October 2005)
  2684 ----------------------------------
  2685 
  2686 *** General ***
  2687 
  2688 * Theory headers: the new header syntax for Isar theories is
  2689 
  2690   theory <name>
  2691   imports <theory1> ... <theoryN>
  2692   uses <file1> ... <fileM>
  2693   begin
  2694 
  2695 where the 'uses' part is optional.  The previous syntax
  2696 
  2697   theory <name> = <theory1> + ... + <theoryN>:
  2698 
  2699 will disappear in the next release.  Use isatool fixheaders to convert
  2700 existing theory files.  Note that there is no change in ancient
  2701 non-Isar theories now, but these will disappear soon.
  2702 
  2703 * Theory loader: parent theories can now also be referred to via
  2704 relative and absolute paths.
  2705 
  2706 * Command 'find_theorems' searches for a list of criteria instead of a
  2707 list of constants. Known criteria are: intro, elim, dest, name:string,
  2708 simp:term, and any term. Criteria can be preceded by '-' to select
  2709 theorems that do not match. Intro, elim, dest select theorems that
  2710 match the current goal, name:s selects theorems whose fully qualified
  2711 name contain s, and simp:term selects all simplification rules whose
  2712 lhs match term.  Any other term is interpreted as pattern and selects
  2713 all theorems matching the pattern. Available in ProofGeneral under
  2714 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2715 
  2716   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2717 
  2718 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2719 matching the current goal as introduction rule and not having "HOL."
  2720 in their name (i.e. not being defined in theory HOL).
  2721 
  2722 * Command 'thms_containing' has been discontinued in favour of
  2723 'find_theorems'; INCOMPATIBILITY.
  2724 
  2725 * Communication with Proof General is now 8bit clean, which means that
  2726 Unicode text in UTF-8 encoding may be used within theory texts (both
  2727 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2728 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2729 
  2730   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2731   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2732 
  2733 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2734 Classical Reasoner.  Typical big applications run around 2 times
  2735 faster.
  2736 
  2737 
  2738 *** Document preparation ***
  2739 
  2740 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2741 of raw sources.  Only those symbols that do not require additional
  2742 LaTeX packages (depending on comments in isabellesym.sty) are
  2743 displayed properly, everything else is left verbatim.  isatool display
  2744 and isatool print are used as front ends (these are subject to the
  2745 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2746 
  2747 * Command tags control specific markup of certain regions of text,
  2748 notably folding and hiding.  Predefined tags include "theory" (for
  2749 theory begin and end), "proof" for proof commands, and "ML" for
  2750 commands involving ML code; the additional tags "visible" and
  2751 "invisible" are unused by default.  Users may give explicit tag
  2752 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2753 interpretation of tags is determined by the LaTeX job during document
  2754 preparation: see option -V of isatool usedir, or options -n and -t of
  2755 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2756 \isadroptag.
  2757 
  2758 Several document versions may be produced at the same time via isatool
  2759 usedir (the generated index.html will link all of them).  Typical
  2760 specifications include ''-V document=theory,proof,ML'' to present
  2761 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2762 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2763 these parts without any formal replacement text.  The Isabelle site
  2764 default settings produce ''document'' and ''outline'' versions as
  2765 specified above.
  2766 
  2767 * Several new antiquotations:
  2768 
  2769   @{term_type term} prints a term with its type annotated;
  2770 
  2771   @{typeof term} prints the type of a term;
  2772 
  2773   @{const const} is the same as @{term const}, but checks that the
  2774   argument is a known logical constant;
  2775 
  2776   @{term_style style term} and @{thm_style style thm} print a term or
  2777   theorem applying a "style" to it
  2778 
  2779   @{ML text}
  2780 
  2781 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2782 definitions, equations, inequations etc., 'concl' printing only the
  2783 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2784 to print the specified premise.  TermStyle.add_style provides an ML
  2785 interface for introducing further styles.  See also the "LaTeX Sugar"
  2786 document practical applications.  The ML antiquotation prints
  2787 type-checked ML expressions verbatim.
  2788 
  2789 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2790 and 'text' support optional locale specification '(in loc)', which
  2791 specifies the default context for interpreting antiquotations.  For
  2792 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2793 
  2794 * Option 'locale=NAME' of antiquotations specifies an alternative
  2795 context interpreting the subsequent argument.  For example: @{thm
  2796 [locale=lattice] inf_assoc}.
  2797 
  2798 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2799 a proof context.
  2800 
  2801 * Proper output of antiquotations for theory commands involving a
  2802 proof context (such as 'locale' or 'theorem (in loc) ...').
  2803 
  2804 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2805 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2806 
  2807 * isatool usedir: new option -C (default true) controls whether option
  2808 -D should include a copy of the original document directory; -C false
  2809 prevents unwanted effects such as copying of administrative CVS data.
  2810 
  2811 
  2812 *** Pure ***
  2813 
  2814 * Considerably improved version of 'constdefs' command.  Now performs
  2815 automatic type-inference of declared constants; additional support for
  2816 local structure declarations (cf. locales and HOL records), see also
  2817 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2818 sequential dependencies of definitions within a single 'constdefs'
  2819 section; moreover, the declared name needs to be an identifier.  If
  2820 all fails, consider to fall back on 'consts' and 'defs' separately.
  2821 
  2822 * Improved indexed syntax and implicit structures.  First of all,
  2823 indexed syntax provides a notational device for subscripted
  2824 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2825 expressions.  Secondly, in a local context with structure
  2826 declarations, number indexes \<^sub>n or the empty index (default
  2827 number 1) refer to a certain fixed variable implicitly; option
  2828 show_structs controls printing of implicit structures.  Typical
  2829 applications of these concepts involve record types and locales.
  2830 
  2831 * New command 'no_syntax' removes grammar declarations (and
  2832 translations) resulting from the given syntax specification, which is
  2833 interpreted in the same manner as for the 'syntax' command.
  2834 
  2835 * 'Advanced' translation functions (parse_translation etc.) may depend
  2836 on the signature of the theory context being presently used for
  2837 parsing/printing, see also isar-ref manual.
  2838 
  2839 * Improved 'oracle' command provides a type-safe interface to turn an
  2840 ML expression of type theory -> T -> term into a primitive rule of
  2841 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2842 is already included here); see also FOL/ex/IffExample.thy;
  2843 INCOMPATIBILITY.
  2844 
  2845 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2846 before); "cI" is no longer bound, use "c.intro" instead.
  2847 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2848 axclasses vs. locales.
  2849 
  2850 * Improved internal renaming of symbolic identifiers -- attach primes
  2851 instead of base 26 numbers.
  2852 
  2853 * New flag show_question_marks controls printing of leading question
  2854 marks in schematic variable names.
  2855 
  2856 * In schematic variable names, *any* symbol following \<^isub> or
  2857 \<^isup> is now treated as part of the base name.  For example, the
  2858 following works without printing of awkward ".0" indexes:
  2859 
  2860   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2861     by simp
  2862 
  2863 * Inner syntax includes (*(*nested*) comments*).
  2864 
  2865 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2866 annotations as "(00...)".
  2867 
  2868 * Clear separation of logical types and nonterminals, where the latter
  2869 may only occur in 'syntax' specifications or type abbreviations.
  2870 Before that distinction was only partially implemented via type class
  2871 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2872 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2873 exotic syntax specifications may require further adaption
  2874 (e.g. Cube/Cube.thy).
  2875 
  2876 * Removed obsolete type class "logic", use the top sort {} instead.
  2877 Note that non-logical types should be declared as 'nonterminals'
  2878 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2879 specifications.
  2880 
  2881 * Attributes 'induct' and 'cases': type or set names may now be
  2882 locally fixed variables as well.
  2883 
  2884 * Simplifier: can now control the depth to which conditional rewriting
  2885 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2886 Limit.
  2887 
  2888 * Simplifier: simplification procedures may now take the current
  2889 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2890 interface), which is very useful for calling the Simplifier
  2891 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2892 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2893 low-level mk_simproc no longer applies Logic.varify internally, to
  2894 allow for use in a context of fixed variables.
  2895 
  2896 * thin_tac now works even if the assumption being deleted contains !!
  2897 or ==>.  More generally, erule now works even if the major premise of
  2898 the elimination rule contains !! or ==>.
  2899 
  2900 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2901 
  2902 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2903 from Pure, which contains all common declarations already.  Both
  2904 theories are defined via plain Isabelle/Isar .thy files.
  2905 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2906 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2907 use isatool fixcpure to adapt your theory and ML sources.
  2908 
  2909 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2910 selections of theorems in named facts via index ranges.
  2911 
  2912 * 'print_theorems': in theory mode, really print the difference
  2913 wrt. the last state (works for interactive theory development only),
  2914 in proof mode print all local facts (cf. 'print_facts');
  2915 
  2916 * 'hide': option '(open)' hides only base names.
  2917 
  2918 * More efficient treatment of intermediate checkpoints in interactive
  2919 theory development.
  2920 
  2921 * Code generator is now invoked via code_module (incremental code
  2922 generation) and code_library (modular code generation, ML structures
  2923 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2924 must be quoted when used as identifiers.
  2925 
  2926 * New 'value' command for reading, evaluating and printing terms using
  2927 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2928 quoted when used as identifier.
  2929 
  2930 
  2931 *** Locales ***
  2932 
  2933 * New commands for the interpretation of locale expressions in
  2934 theories (1), locales (2) and proof contexts (3).  These generate
  2935 proof obligations from the expression specification.  After the
  2936 obligations have been discharged, theorems of the expression are added
  2937 to the theory, target locale or proof context.  The synopsis of the
  2938 commands is a follows:
  2939 
  2940   (1) interpretation expr inst
  2941   (2) interpretation target < expr
  2942   (3) interpret expr inst
  2943 
  2944 Interpretation in theories and proof contexts require a parameter
  2945 instantiation of terms from the current context.  This is applied to
  2946 specifications and theorems of the interpreted expression.
  2947 Interpretation in locales only permits parameter renaming through the
  2948 locale expression.  Interpretation is smart in that interpretations
  2949 that are active already do not occur in proof obligations, neither are
  2950 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2951 inspect active interpretations of a particular locale.  For details,
  2952 see the Isar Reference manual.  Examples can be found in
  2953 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2954 
  2955 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2956 'interpret' instead.
  2957 
  2958 * New context element 'constrains' for adding type constraints to
  2959 parameters.
  2960 
  2961 * Context expressions: renaming of parameters with syntax
  2962 redeclaration.
  2963 
  2964 * Locale declaration: 'includes' disallowed.
  2965 
  2966 * Proper static binding of attribute syntax -- i.e. types / terms /
  2967 facts mentioned as arguments are always those of the locale definition
  2968 context, independently of the context of later invocations.  Moreover,
  2969 locale operations (renaming and type / term instantiation) are applied
  2970 to attribute arguments as expected.
  2971 
  2972 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2973 actual attributes; rare situations may require Attrib.attribute to
  2974 embed those attributes into Attrib.src that lack concrete syntax.
  2975 Attribute implementations need to cooperate properly with the static
  2976 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2977 Attrib.XXX_thm etc. already do the right thing without further
  2978 intervention.  Only unusual applications -- such as "where" or "of"
  2979 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2980 on the context and the facts involved -- may have to assign parsed
  2981 values to argument tokens explicitly.
  2982 
  2983 * Changed parameter management in theorem generation for long goal
  2984 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2985 theorem statement in rare situations.
  2986 
  2987 * Locale inspection command 'print_locale' omits notes elements.  Use
  2988 'print_locale!' to have them included in the output.
  2989 
  2990 
  2991 *** Provers ***
  2992 
  2993 * Provers/hypsubst.ML: improved version of the subst method, for
  2994 single-step rewriting: it now works in bound variable contexts. New is
  2995 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2996 rewrite a different subterm than the original subst method, which is
  2997 still available as 'simplesubst'.
  2998 
  2999 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  3000 and quasi orders.
  3001 
  3002 * Provers/trancl.ML: new transitivity reasoner for transitive and
  3003 reflexive-transitive closure of relations.
  3004 
  3005 * Provers/blast.ML: new reference depth_limit to make blast's depth
  3006 limit (previously hard-coded with a value of 20) user-definable.
  3007 
  3008 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  3009 is peformed already.  Object-logics merely need to finish their
  3010 initial simpset configuration as before.  INCOMPATIBILITY.
  3011 
  3012 
  3013 *** HOL ***
  3014 
  3015 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3016 
  3017   syntax (epsilon)
  3018     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3019 
  3020 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3021 and x-symbol; use option '-m epsilon' to get it actually printed.
  3022 Moreover, the mathematically important symbolic identifier \<epsilon>
  3023 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3024 
  3025 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3026 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3027 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3028 support corresponding Isar calculations.
  3029 
  3030 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3031 instead of ":".
  3032 
  3033 * theory SetInterval: changed the syntax for open intervals:
  3034 
  3035   Old       New
  3036   {..n(}    {..<n}
  3037   {)n..}    {n<..}
  3038   {m..n(}   {m..<n}
  3039   {)m..n}   {m<..n}
  3040   {)m..n(}  {m<..<n}
  3041 
  3042 The old syntax is still supported but will disappear in the next
  3043 release.  For conversion use the following Emacs search and replace
  3044 patterns (these are not perfect but work quite well):
  3045 
  3046   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3047   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3048 
  3049 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3050 equalities in commutative rings; method 'algebra' provides a generic
  3051 interface.
  3052 
  3053 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3054 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3055 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3056 be a tuple pattern.
  3057 
  3058 Some new syntax forms are available:
  3059 
  3060   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3061   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3062   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3063   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3064 
  3065 The latter form "\<Sum>x < k. e" used to be based on a separate
  3066 function "Summation", which has been discontinued.
  3067 
  3068 * theory Finite_Set: in structured induction proofs, the insert case
  3069 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3070 (insert F x)'.
  3071 
  3072 * The 'refute' command has been extended to support a much larger
  3073 fragment of HOL, including axiomatic type classes, constdefs and
  3074 typedefs, inductive datatypes and recursion.
  3075 
  3076 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3077 Requires zChaff with proof generation to be installed.  See
  3078 HOL/ex/SAT_Examples.thy for examples.
  3079 
  3080 * Datatype induction via method 'induct' now preserves the name of the
  3081 induction variable. For example, when proving P(xs::'a list) by
  3082 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3083 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3084 in unstructured proof scripts.
  3085 
  3086 * Reworked implementation of records.  Improved scalability for
  3087 records with many fields, avoiding performance problems for type
  3088 inference. Records are no longer composed of nested field types, but
  3089 of nested extension types. Therefore the record type only grows linear
  3090 in the number of extensions and not in the number of fields.  The
  3091 top-level (users) view on records is preserved.  Potential
  3092 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3093 old record representation. The type generated for a record is called
  3094 <record_name>_ext_type.
  3095 
  3096 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3097 proofs triggered by a record definition or a simproc (if
  3098 quick_and_dirty is enabled).  Definitions of large records can take
  3099 quite long.
  3100 
  3101 New simproc record_upd_simproc for simplification of multiple record
  3102 updates enabled by default.  Moreover, trivial updates are also
  3103 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3104 occasionally, since simplification is more powerful by default.
  3105 
  3106 * typedef: proper support for polymorphic sets, which contain extra
  3107 type-variables in the term.
  3108 
  3109 * Simplifier: automatically reasons about transitivity chains
  3110 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3111 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3112 old proofs break occasionally as simplification may now solve more
  3113 goals than previously.
  3114 
  3115 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3116 present.  Works for all partial orders (class "order"), in particular
  3117 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3118 just like y <= x.
  3119 
  3120 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3121 bound variable or a constant then the let is unfolded.  Otherwise
  3122 first a is simplified to b, and then f b is simplified to g. If
  3123 possible we abstract b from g arriving at "let x = b in h x",
  3124 otherwise we unfold the let and arrive at g.  The simproc can be
  3125 enabled/disabled by the reference use_let_simproc.  Potential
  3126 INCOMPATIBILITY since simplification is more powerful by default.
  3127 
  3128 * Classical reasoning: the meson method now accepts theorems as arguments.
  3129 
  3130 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3131 jobs to provide advice on the provability of subgoals.
  3132 
  3133 * Theory OrderedGroup and Ring_and_Field: various additions and
  3134 improvements to faciliate calculations involving equalities and
  3135 inequalities.
  3136 
  3137 The following theorems have been eliminated or modified
  3138 (INCOMPATIBILITY):
  3139 
  3140   abs_eq             now named abs_of_nonneg
  3141   abs_of_ge_0        now named abs_of_nonneg
  3142   abs_minus_eq       now named abs_of_nonpos
  3143   imp_abs_id         now named abs_of_nonneg
  3144   imp_abs_neg_id     now named abs_of_nonpos
  3145   mult_pos           now named mult_pos_pos
  3146   mult_pos_le        now named mult_nonneg_nonneg
  3147   mult_pos_neg_le    now named mult_nonneg_nonpos
  3148   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3149   mult_neg           now named mult_neg_neg
  3150   mult_neg_le        now named mult_nonpos_nonpos
  3151 
  3152 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3153      
  3154      zero_le_square
  3155      not_square_less_zero 
  3156 
  3157   The following lemmas have been deleted from Real/RealPow:
  3158   
  3159      realpow_zero_zero
  3160      realpow_two
  3161      realpow_less
  3162      zero_le_power
  3163      realpow_two_le
  3164      abs_realpow_two
  3165      realpow_two_abs     
  3166 
  3167 * Theory Parity: added rules for simplifying exponents.
  3168 
  3169 * Theory List:
  3170 
  3171 The following theorems have been eliminated or modified
  3172 (INCOMPATIBILITY):
  3173 
  3174   list_all_Nil       now named list_all.simps(1)
  3175   list_all_Cons      now named list_all.simps(2)
  3176   list_all_conv      now named list_all_iff
  3177   set_mem_eq         now named mem_iff
  3178 
  3179 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3180 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3181 
  3182 
  3183 *** HOL-Complex ***
  3184 
  3185 * Theory RealDef: better support for embedding natural numbers and
  3186 integers in the reals.
  3187 
  3188 The following theorems have been eliminated or modified
  3189 (INCOMPATIBILITY):
  3190 
  3191   exp_ge_add_one_self  now requires no hypotheses
  3192   real_of_int_add      reversed direction of equality (use [symmetric])
  3193   real_of_int_minus    reversed direction of equality (use [symmetric])
  3194   real_of_int_diff     reversed direction of equality (use [symmetric])
  3195   real_of_int_mult     reversed direction of equality (use [symmetric])
  3196 
  3197 * Theory RComplete: expanded support for floor and ceiling functions.
  3198 
  3199 * Theory Ln is new, with properties of the natural logarithm
  3200 
  3201 * Hyperreal: There is a new type constructor "star" for making
  3202 nonstandard types.  The old type names are now type synonyms:
  3203 
  3204   hypreal = real star
  3205   hypnat = nat star
  3206   hcomplex = complex star
  3207 
  3208 * Hyperreal: Many groups of similarly-defined constants have been
  3209 replaced by polymorphic versions (INCOMPATIBILITY):
  3210 
  3211   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3212 
  3213   starset      <-- starsetNat, starsetC
  3214   *s*          <-- *sNat*, *sc*
  3215   starset_n    <-- starsetNat_n, starsetC_n
  3216   *sn*         <-- *sNatn*, *scn*
  3217   InternalSets <-- InternalNatSets, InternalCSets
  3218 
  3219   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3220   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3221   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3222   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3223   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3224 
  3225 * Hyperreal: Many type-specific theorems have been removed in favor of
  3226 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3227 
  3228   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3229   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3230   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3231   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3232   right_minus <-- hypreal_add_minus
  3233   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3234   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3235   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3236   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3237   mult_1_right <-- hcomplex_mult_one_right
  3238   mult_zero_left <-- hcomplex_mult_zero_left
  3239   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3240   right_distrib <-- hypnat_add_mult_distrib2
  3241   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3242   right_inverse <-- hypreal_mult_inverse
  3243   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3244   order_refl <-- {hypreal,hypnat}_le_refl
  3245   order_trans <-- {hypreal,hypnat}_le_trans
  3246   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3247   order_less_le <-- {hypreal,hypnat}_less_le
  3248   linorder_linear <-- {hypreal,hypnat}_le_linear
  3249   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3250   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3251   add_nonneg_nonneg <-- hypreal_le_add_order
  3252 
  3253 * Hyperreal: Separate theorems having to do with type-specific
  3254 versions of constants have been merged into theorems that apply to the
  3255 new polymorphic constants (INCOMPATIBILITY):
  3256 
  3257   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3258   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3259   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3260   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3261   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3262   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3263   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3264   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3265   STAR_diff <-- {STAR,STARC}_diff
  3266   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3267     STARC_hcomplex_of_complex}_image_subset
  3268   starset_n_Un <-- starset{Nat,C}_n_Un
  3269   starset_n_Int <-- starset{Nat,C}_n_Int
  3270   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3271   starset_n_diff <-- starset{Nat,C}_n_diff
  3272   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3273   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3274   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3275   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3276   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3277   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3278   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3279   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3280   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3281   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3282   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3283   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3284   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3285   starfun_diff <-- starfun{C,RC,CR}_diff
  3286   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3287   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3288   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3289   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3290   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3291   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3292   starfun_Id <-- starfunC_Id
  3293   starfun_approx <-- starfun{Nat,CR}_approx
  3294   starfun_capprox <-- starfun{C,RC}_capprox
  3295   starfun_abs <-- starfunNat_rabs
  3296   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3297   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3298   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3299   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3300   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3301   starfun_add_approx <-- starfunCR_add_approx
  3302   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3303   starfun_divide <-- starfun{C,CR,RC}_divide
  3304   starfun_n <-- starfun{Nat,C}_n
  3305   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3306   starfun_n_add <-- starfun{Nat,C}_n_add
  3307   starfun_n_add_minus <-- starfunNat_n_add_minus
  3308   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3309   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3310   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3311 
  3312   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3313   star_n_minus <-- {hypreal,hcomplex}_minus
  3314   star_n_diff <-- {hypreal,hcomplex}_diff
  3315   star_n_mult <-- {hypreal,hcomplex}_mult
  3316   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3317   star_n_le <-- {hypreal,hypnat}_le
  3318   star_n_less <-- {hypreal,hypnat}_less
  3319   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3320   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3321   star_n_abs <-- hypreal_hrabs
  3322   star_n_divide <-- hcomplex_divide
  3323 
  3324   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3325   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3326   star_of_diff <-- hypreal_of_real_diff
  3327   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3328   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3329   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3330   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3331   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3332   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3333   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3334   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3335   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3336   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3337   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3338   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3339   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3340   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3341   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3342   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3343   star_of_power <-- hypreal_of_real_power
  3344   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3345 
  3346 * Hyperreal: new method "transfer" that implements the transfer
  3347 principle of nonstandard analysis. With a subgoal that mentions
  3348 nonstandard types like "'a star", the command "apply transfer"
  3349 replaces it with an equivalent one that mentions only standard types.
  3350 To be successful, all free variables must have standard types; non-
  3351 standard variables must have explicit universal quantifiers.
  3352 
  3353 * Hyperreal: A theory of Taylor series.
  3354 
  3355 
  3356 *** HOLCF ***
  3357 
  3358 * Discontinued special version of 'constdefs' (which used to support
  3359 continuous functions) in favor of the general Pure one with full
  3360 type-inference.
  3361 
  3362 * New simplification procedure for solving continuity conditions; it
  3363 is much faster on terms with many nested lambda abstractions (cubic
  3364 instead of exponential time).
  3365 
  3366 * New syntax for domain package: selector names are now optional.
  3367 Parentheses should be omitted unless argument is lazy, for example:
  3368 
  3369   domain 'a stream = cons "'a" (lazy "'a stream")
  3370 
  3371 * New command 'fixrec' for defining recursive functions with pattern
  3372 matching; defining multiple functions with mutual recursion is also
  3373 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3374 sinr, or any data constructor defined by the domain package. The given
  3375 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3376 syntax and examples.
  3377 
  3378 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3379 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3380 but the proof obligation additionally includes an admissibility
  3381 requirement. The packages generate instances of class cpo or pcpo,
  3382 with continuity and strictness theorems for Rep and Abs.
  3383 
  3384 * HOLCF: Many theorems have been renamed according to a more standard naming
  3385 scheme (INCOMPATIBILITY):
  3386 
  3387   foo_inject:  "foo$x = foo$y ==> x = y"
  3388   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3389   foo_less:    "(foo$x << foo$y) = (x << y)"
  3390   foo_strict:  "foo$UU = UU"
  3391   foo_defined: "... ==> foo$x ~= UU"
  3392   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3393 
  3394 
  3395 *** ZF ***
  3396 
  3397 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3398 including the First Isomorphism Theorem (on quotienting by the kernel
  3399 of a homomorphism).
  3400 
  3401 * ZF/Simplifier: install second copy of type solver that actually
  3402 makes use of TC rules declared to Isar proof contexts (or locales);
  3403 the old version is still required for ML proof scripts.
  3404 
  3405 
  3406 *** Cube ***
  3407 
  3408 * Converted to Isar theory format; use locales instead of axiomatic
  3409 theories.
  3410 
  3411 
  3412 *** ML ***
  3413 
  3414 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3415 for ||>, ||>>, |>>,
  3416 
  3417 * Pure/library.ML no longer defines its own option datatype, but uses
  3418 that of the SML basis, which has constructors NONE and SOME instead of
  3419 None and Some, as well as exception Option.Option instead of OPTION.
  3420 The functions the, if_none, is_some, is_none have been adapted
  3421 accordingly, while Option.map replaces apsome.
  3422 
  3423 * Pure/library.ML: the exception LIST has been given up in favour of
  3424 the standard exceptions Empty and Subscript, as well as
  3425 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3426 superceded by the standard hd and tl functions etc.
  3427 
  3428 A number of basic list functions are no longer exported to the ML
  3429 toplevel, as they are variants of predefined functions.  The following
  3430 suggests how one can translate existing code:
  3431 
  3432     rev_append xs ys = List.revAppend (xs, ys)
  3433     nth_elem (i, xs) = List.nth (xs, i)
  3434     last_elem xs = List.last xs
  3435     flat xss = List.concat xss
  3436     seq fs = List.app fs
  3437     partition P xs = List.partition P xs
  3438     mapfilter f xs = List.mapPartial f xs
  3439 
  3440 * Pure/library.ML: several combinators for linear functional
  3441 transformations, notably reverse application and composition:
  3442 
  3443   x |> f                f #> g
  3444   (x, y) |-> f          f #-> g
  3445 
  3446 * Pure/library.ML: introduced/changed precedence of infix operators:
  3447 
  3448   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3449   infix 2 ?;
  3450   infix 3 o oo ooo oooo;
  3451   infix 4 ~~ upto downto;
  3452 
  3453 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3454 infix operators.
  3455 
  3456 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3457 fold_map support linear functional transformations and nesting.  For
  3458 example:
  3459 
  3460   fold f [x1, ..., xN] y =
  3461     y |> f x1 |> ... |> f xN
  3462 
  3463   (fold o fold) f [xs1, ..., xsN] y =
  3464     y |> fold f xs1 |> ... |> fold f xsN
  3465 
  3466   fold f [x1, ..., xN] =
  3467     f x1 #> ... #> f xN
  3468 
  3469   (fold o fold) f [xs1, ..., xsN] =
  3470     fold f xs1 #> ... #> fold f xsN
  3471 
  3472 * Pure/library.ML: the following selectors on type 'a option are
  3473 available:
  3474 
  3475   the:               'a option -> 'a  (*partial*)
  3476   these:             'a option -> 'a  where 'a = 'b list
  3477   the_default: 'a -> 'a option -> 'a
  3478   the_list:          'a option -> 'a list
  3479 
  3480 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3481 basic operations for association lists, following natural argument
  3482 order; moreover the explicit equality predicate passed here avoids
  3483 potentially expensive polymorphic runtime equality checks.
  3484 The old functions may be expressed as follows:
  3485 
  3486   assoc = uncurry (AList.lookup (op =))
  3487   assocs = these oo AList.lookup (op =)
  3488   overwrite = uncurry (AList.update (op =)) o swap
  3489 
  3490 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3491 
  3492   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3493   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3494 
  3495 replacing make_keylist and keyfilter (occassionally used)
  3496 Naive rewrites:
  3497 
  3498   make_keylist = AList.make
  3499   keyfilter = AList.find (op =)
  3500 
  3501 * eq_fst and eq_snd now take explicit equality parameter, thus
  3502   avoiding eqtypes. Naive rewrites:
  3503 
  3504     eq_fst = eq_fst (op =)
  3505     eq_snd = eq_snd (op =)
  3506 
  3507 * Removed deprecated apl and apr (rarely used).
  3508   Naive rewrites:
  3509 
  3510     apl (n, op) =>>= curry op n
  3511     apr (op, m) =>>= fn n => op (n, m)
  3512 
  3513 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3514 provides a reasonably efficient light-weight implementation of sets as
  3515 lists.
  3516 
  3517 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3518 few new operations; existing lookup and update are now curried to
  3519 follow natural argument order (for use with fold etc.);
  3520 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3521 
  3522 * Pure/General: output via the Isabelle channels of
  3523 writeln/warning/error etc. is now passed through Output.output, with a
  3524 hook for arbitrary transformations depending on the print_mode
  3525 (cf. Output.add_mode -- the first active mode that provides a output
  3526 function wins).  Already formatted output may be embedded into further
  3527 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3528 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3529 accommodate easy composition of diagnostic messages etc.  Programmers
  3530 rarely need to care about Output.output or Output.raw at all, with
  3531 some notable exceptions: Output.output is required when bypassing the
  3532 standard channels (writeln etc.), or in token translations to produce
  3533 properly formatted results; Output.raw is required when capturing
  3534 already output material that will eventually be presented to the user
  3535 a second time.  For the default print mode, both Output.output and
  3536 Output.raw have no effect.
  3537 
  3538 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3539 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3540 cumulative results are displayed at the end of a batch session.
  3541 
  3542 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3543 replaced by File.platform_path and File.shell_path (with appropriate
  3544 hooks).  This provides a clean interface for unusual systems where the
  3545 internal and external process view of file names are different.
  3546 
  3547 * Pure: more efficient orders for basic syntactic entities: added
  3548 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3549 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3550 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3551 orders now -- potential INCOMPATIBILITY for code that depends on a
  3552 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3553 Library.sort_strings on result).
  3554 
  3555 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3556 fold_types traverse types/terms from left to right, observing natural
  3557 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3558 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3559 
  3560 * Pure: name spaces have been refined, with significant changes of the
  3561 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3562 to extern(_table).  The plain name entry path is superceded by a
  3563 general 'naming' context, which also includes the 'policy' to produce
  3564 a fully qualified name and external accesses of a fully qualified
  3565 name; NameSpace.extend is superceded by context dependent
  3566 Sign.declare_name.  Several theory and proof context operations modify
  3567 the naming context.  Especially note Theory.restore_naming and
  3568 ProofContext.restore_naming to get back to a sane state; note that
  3569 Theory.add_path is no longer sufficient to recover from
  3570 Theory.absolute_path in particular.
  3571 
  3572 * Pure: new flags short_names (default false) and unique_names
  3573 (default true) for controlling output of qualified names.  If
  3574 short_names is set, names are printed unqualified.  If unique_names is
  3575 reset, the name prefix is reduced to the minimum required to achieve
  3576 the original result when interning again, even if there is an overlap
  3577 with earlier declarations.
  3578 
  3579 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3580 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3581 (useful for printing error messages).  INCOMPATIBILITY.
  3582 
  3583 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3584 Theory.theory are now identified, referring to the universal
  3585 Context.theory (see Pure/context.ML).  Actual signature and theory
  3586 content is managed as theory data.  The old code and interfaces were
  3587 spread over many files and structures; the new arrangement introduces
  3588 considerable INCOMPATIBILITY to gain more clarity:
  3589 
  3590   Context -- theory management operations (name, identity, inclusion,
  3591     parents, ancestors, merge, etc.), plus generic theory data;
  3592 
  3593   Sign -- logical signature and syntax operations (declaring consts,
  3594     types, etc.), plus certify/read for common entities;
  3595 
  3596   Theory -- logical theory operations (stating axioms, definitions,
  3597     oracles), plus a copy of logical signature operations (consts,
  3598     types, etc.); also a few basic management operations (Theory.copy,
  3599     Theory.merge, etc.)
  3600 
  3601 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3602 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3603 for convenience -- they merely return the theory.
  3604 
  3605 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3606 
  3607 * Pure: the Isar proof context type is already defined early in Pure
  3608 as Context.proof (note that ProofContext.context and Proof.context are
  3609 aliases, where the latter is the preferred name).  This enables other
  3610 Isabelle components to refer to that type even before Isar is present.
  3611 
  3612 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3613 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3614 any of these kinds.  For example, Sign.intern typeK is now
  3615 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3616 Theory.hide_types.  Also note that former
  3617 Theory.hide_classes/types/consts are now
  3618 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3619 internalize their arguments!  INCOMPATIBILITY.
  3620 
  3621 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3622 datatype thmref (with constructors Name and NameSelection) instead of
  3623 plain string -- INCOMPATIBILITY;
  3624 
  3625 * Pure: cases produced by proof methods specify options, where NONE
  3626 means to remove case bindings -- INCOMPATIBILITY in
  3627 (RAW_)METHOD_CASES.
  3628 
  3629 * Pure: the following operations retrieve axioms or theorems from a
  3630 theory node or theory hierarchy, respectively:
  3631 
  3632   Theory.axioms_of: theory -> (string * term) list
  3633   Theory.all_axioms_of: theory -> (string * term) list
  3634   PureThy.thms_of: theory -> (string * thm) list
  3635   PureThy.all_thms_of: theory -> (string * thm) list
  3636 
  3637 * Pure: print_tac now outputs the goal through the trace channel.
  3638 
  3639 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3640 Reference Toplevel.debug (default false) controls detailed printing
  3641 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3642 controls execution profiling -- set to 1 for time and 2 for space
  3643 (both increase the runtime).
  3644 
  3645 * Isar session: The initial use of ROOT.ML is now always timed,
  3646 i.e. the log will show the actual process times, in contrast to the
  3647 elapsed wall-clock time that the outer shell wrapper produces.
  3648 
  3649 * Simplifier: improved handling of bound variables (nameless
  3650 representation, avoid allocating new strings).  Simprocs that invoke
  3651 the Simplifier recursively should use Simplifier.inherit_bounds to
  3652 avoid local name clashes.  Failure to do so produces warnings
  3653 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3654 for further details.
  3655 
  3656 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3657 bindings for all theorems stored within a given theory; this may help
  3658 in porting non-Isar theories to Isar ones, while keeping ML proof
  3659 scripts for the time being.
  3660 
  3661 * ML operator HTML.with_charset specifies the charset begin used for
  3662 generated HTML files.  For example:
  3663 
  3664   HTML.with_charset "utf-8" use_thy "Hebrew";
  3665   HTML.with_charset "utf-8" use_thy "Chinese";
  3666 
  3667 
  3668 *** System ***
  3669 
  3670 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3671 isabelle, isatool etc.).
  3672 
  3673 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3674 isatool doc, isatool mkdir, display_drafts etc.).
  3675 
  3676 * isatool usedir: option -f allows specification of the ML file to be
  3677 used by Isabelle; default is ROOT.ML.
  3678 
  3679 * New isatool version outputs the version identifier of the Isabelle
  3680 distribution being used.
  3681 
  3682 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3683 (containing Boolean satisfiability problems) into Isabelle/HOL
  3684 theories.
  3685 
  3686 
  3687 
  3688 New in Isabelle2004 (April 2004)
  3689 --------------------------------
  3690 
  3691 *** General ***
  3692 
  3693 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3694   Replaces linorder.ML.
  3695 
  3696 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3697   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3698   (\<a>...\<z>), are now considered normal letters, and can therefore
  3699   be used anywhere where an ASCII letter (a...zA...Z) has until
  3700   now. COMPATIBILITY: This obviously changes the parsing of some
  3701   terms, especially where a symbol has been used as a binder, say
  3702   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3703   as an identifier.  Fix it by inserting a space around former
  3704   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3705   existing theory and ML files.
  3706 
  3707 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3708 
  3709 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3710   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3711   a normal (but invisible) letter. For multiple letter subscripts repeat
  3712   \<^isub> like this: x\<^isub>1\<^isub>2.
  3713 
  3714 * Pure: There are now sub-/superscripts that can span more than one
  3715   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3716   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3717   superscript. The new control characters are not identifier parts.
  3718 
  3719 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3720   content of "..." to the latex file instead of \isacntrl... . The "..."
  3721   may consist of any printable characters excluding the end bracket >.
  3722 
  3723 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3724   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3725   declare constants "final", which prevents their being given a definition
  3726   later.  It is useful for constants whose behaviour is fixed axiomatically
  3727   rather than definitionally, such as the meta-logic connectives.
  3728 
  3729 * Pure: 'instance' now handles general arities with general sorts
  3730   (i.e. intersections of classes),
  3731 
  3732 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3733   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3734   It can be changed to alter the colors/layout of generated pages.
  3735 
  3736 
  3737 *** Isar ***
  3738 
  3739 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3740   cut_tac, subgoal_tac and thin_tac:
  3741   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3742     locales are no longer forced to write Isar proof scripts.
  3743     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3744     emulations.
  3745   - INCOMPATIBILITY: names of variables to be instantiated may no
  3746     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3747     This is consistent with the instantiation attribute "where".
  3748 
  3749 * Attributes "where" and "of":
  3750   - Now take type variables of instantiated theorem into account when reading
  3751     the instantiation string.  This fixes a bug that caused instantiated
  3752     theorems to have too special types in some circumstances.
  3753   - "where" permits explicit instantiations of type variables.
  3754 
  3755 * Calculation commands "moreover" and "also" no longer interfere with
  3756   current facts ("this"), admitting arbitrary combinations with "then"
  3757   and derived forms.
  3758 
  3759 * Locales:
  3760   - Goal statements involving the context element "includes" no longer
  3761     generate theorems with internal delta predicates (those ending on
  3762     "_axioms") in the premise.
  3763     Resolve particular premise with <locale>.intro to obtain old form.
  3764   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3765     specification and "includes" elements in goal statement.
  3766   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3767     [intro?] and [elim?] (respectively) by default.
  3768   - Experimental command for instantiation of locales in proof contexts:
  3769         instantiate <label>[<attrs>]: <loc>
  3770     Instantiates locale <loc> and adds all its theorems to the current context
  3771     taking into account their attributes.  Label and attrs are optional
  3772     modifiers, like in theorem declarations.  If present, names of
  3773     instantiated theorems are qualified with <label>, and the attributes
  3774     <attrs> are applied after any attributes these theorems might have already.
  3775       If the locale has assumptions, a chained fact of the form
  3776     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3777     are derived.  The command does not support old-style locales declared
  3778     with "locale (open)".
  3779       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3780 
  3781 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3782   (Isar) contexts.
  3783 
  3784 
  3785 *** HOL ***
  3786 
  3787 * Proof import: new image HOL4 contains the imported library from
  3788   the HOL4 system with about 2500 theorems. It is imported by
  3789   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3790   can be used like any other Isabelle image.  See
  3791   HOL/Import/HOL/README for more information.
  3792 
  3793 * Simplifier:
  3794   - Much improved handling of linear and partial orders.
  3795     Reasoners for linear and partial orders are set up for type classes
  3796     "linorder" and "order" respectively, and are added to the default simpset
  3797     as solvers.  This means that the simplifier can build transitivity chains
  3798     to solve goals from the assumptions.
  3799   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3800     of blast or auto after simplification become unnecessary because the goal
  3801     is solved by simplification already.
  3802 
  3803 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3804     all proved in axiomatic type classes for semirings, rings and fields.
  3805 
  3806 * Numerics:
  3807   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3808     now formalized using the Ring_and_Field theory mentioned above.
  3809   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3810     than before, because now they are set up once in a generic manner.
  3811   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3812     Look for the general versions in Ring_and_Field (and Power if they concern
  3813     exponentiation).
  3814 
  3815 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3816 
  3817 * Records:
  3818   - Record types are now by default printed with their type abbreviation
  3819     instead of the list of all field types. This can be configured via
  3820     the reference "print_record_type_abbr".
  3821   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3822     (not enabled by default).
  3823   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3824     EX x. x = sel r to True (not enabled by default).
  3825   - Tactic "record_split_simp_tac" to split and simplify records added.
  3826 
  3827 * 'specification' command added, allowing for definition by
  3828   specification.  There is also an 'ax_specification' command that
  3829   introduces the new constants axiomatically.
  3830 
  3831 * arith(_tac) is now able to generate counterexamples for reals as well.
  3832 
  3833 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3834 
  3835 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3836   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3837 
  3838 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3839   matrix theory to linear programming.
  3840 
  3841 * Unions and Intersections:
  3842   The latex output syntax of UN and INT has been changed
  3843   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3844   i.e. the index formulae has become a subscript.
  3845   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3846 
  3847 * Unions and Intersections over Intervals:
  3848   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3849   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3850   like in normal math, and corresponding versions for < and for intersection.
  3851 
  3852 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3853   lexicographic dictonary ordering has been added as "lexord".
  3854 
  3855 * ML: the legacy theory structures Int and List have been removed. They had
  3856   conflicted with ML Basis Library structures having the same names.
  3857 
  3858 * 'refute' command added to search for (finite) countermodels.  Only works
  3859   for a fragment of HOL.  The installation of an external SAT solver is
  3860   highly recommended.  See "HOL/Refute.thy" for details.
  3861 
  3862 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3863   formulae under an assignment of free variables to random values.
  3864   In contrast to 'refute', it can deal with inductive datatypes,
  3865   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3866   for examples.
  3867 
  3868 
  3869 *** HOLCF ***
  3870 
  3871 * Streams now come with concatenation and are part of the HOLCF image
  3872 
  3873 
  3874 
  3875 New in Isabelle2003 (May 2003)
  3876 ------------------------------
  3877 
  3878 *** General ***
  3879 
  3880 * Provers/simplifier:
  3881 
  3882   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3883     Assumptions are now subject to complete mutual simplification,
  3884     not just from left to right. The simplifier now preserves
  3885     the order of assumptions.
  3886 
  3887     Potential INCOMPATIBILITY:
  3888 
  3889     -- simp sometimes diverges where the old version did
  3890        not, e.g. invoking simp on the goal
  3891 
  3892         [| P (f x); y = x; f x = f y |] ==> Q
  3893 
  3894        now gives rise to the infinite reduction sequence
  3895 
  3896         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3897 
  3898        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3899        kind of problem.
  3900 
  3901     -- Tactics combining classical reasoner and simplification (such as auto)
  3902        are also affected by this change, because many of them rely on
  3903        simp. They may sometimes diverge as well or yield a different numbers
  3904        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3905        in case of problems. Sometimes subsequent calls to the classical
  3906        reasoner will fail because a preceeding call to the simplifier too
  3907        eagerly simplified the goal, e.g. deleted redundant premises.
  3908 
  3909   - The simplifier trace now shows the names of the applied rewrite rules
  3910 
  3911   - You can limit the number of recursive invocations of the simplifier
  3912     during conditional rewriting (where the simplifie tries to solve the
  3913     conditions before applying the rewrite rule):
  3914     ML "simp_depth_limit := n"
  3915     where n is an integer. Thus you can force termination where previously
  3916     the simplifier would diverge.
  3917 
  3918   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3919 
  3920   - No longer aborts on failed congruence proof.  Instead, the
  3921     congruence is ignored.
  3922 
  3923 * Pure: New generic framework for extracting programs from constructive
  3924   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3925   as HOL/Extraction for some case studies.
  3926 
  3927 * Pure: The main goal of the proof state is no longer shown by default, only
  3928 the subgoals. This behaviour is controlled by a new flag.
  3929    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3930 (ML: Proof.show_main_goal).
  3931 
  3932 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3933 rules whose conclusion matches subgoal 1:
  3934       PG menu: Isabelle/Isar -> Show me -> matching rules
  3935 The rules are ordered by how closely they match the subgoal.
  3936 In particular, rules that solve a subgoal outright are displayed first
  3937 (or rather last, the way they are printed).
  3938 (ML: ProofGeneral.print_intros())
  3939 
  3940 * Pure: New flag trace_unify_fail causes unification to print
  3941 diagnostic information (PG: in trace buffer) when it fails. This is
  3942 useful for figuring out why single step proofs like rule, erule or
  3943 assumption failed.
  3944 
  3945 * Pure: Locale specifications now produce predicate definitions
  3946 according to the body of text (covering assumptions modulo local
  3947 definitions); predicate "loc_axioms" covers newly introduced text,
  3948 while "loc" is cumulative wrt. all included locale expressions; the
  3949 latter view is presented only on export into the global theory
  3950 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3951 on the old view without predicates;
  3952 
  3953 * Pure: predefined locales "var" and "struct" are useful for sharing
  3954 parameters (as in CASL, for example); just specify something like
  3955 ``var x + var y + struct M'' as import;
  3956 
  3957 * Pure: improved thms_containing: proper indexing of facts instead of
  3958 raw theorems; check validity of results wrt. current name space;
  3959 include local facts of proof configuration (also covers active
  3960 locales), cover fixed variables in index; may use "_" in term
  3961 specification; an optional limit for the number of printed facts may
  3962 be given (the default is 40);
  3963 
  3964 * Pure: disallow duplicate fact bindings within new-style theory files
  3965 (batch-mode only);
  3966 
  3967 * Provers: improved induct method: assumptions introduced by case
  3968 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3969 the goal statement); "foo" still refers to all facts collectively;
  3970 
  3971 * Provers: the function blast.overloaded has been removed: all constants
  3972 are regarded as potentially overloaded, which improves robustness in exchange
  3973 for slight decrease in efficiency;
  3974 
  3975 * Provers/linorder: New generic prover for transitivity reasoning over
  3976 linear orders.  Note: this prover is not efficient!
  3977 
  3978 * Isar: preview of problems to finish 'show' now produce an error
  3979 rather than just a warning (in interactive mode);
  3980 
  3981 
  3982 *** HOL ***
  3983 
  3984 * arith(_tac)
  3985 
  3986  - Produces a counter example if it cannot prove a goal.
  3987    Note that the counter example may be spurious if the goal is not a formula
  3988    of quantifier-free linear arithmetic.
  3989    In ProofGeneral the counter example appears in the trace buffer.
  3990 
  3991  - Knows about div k and mod k where k is a numeral of type nat or int.
  3992 
  3993  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3994    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3995    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3996 
  3997 * simp's arithmetic capabilities have been enhanced a bit: it now
  3998 takes ~= in premises into account (by performing a case split);
  3999 
  4000 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  4001 are distributed over a sum of terms;
  4002 
  4003 * New tactic "trans_tac" and method "trans" instantiate
  4004 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  4005 "<=", "<" and "=").
  4006 
  4007 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  4008 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  4009 
  4010 * 'typedef' command has new option "open" to suppress the set
  4011 definition;
  4012 
  4013 * functions Min and Max on finite sets have been introduced (theory
  4014 Finite_Set);
  4015 
  4016 * attribute [symmetric] now works for relations as well; it turns
  4017 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4018 
  4019 * induct over a !!-quantified statement (say !!x1..xn):
  4020   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4021 
  4022 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4023 %x. None. Warning: empty_def now refers to the previously hidden definition
  4024 of the empty set.
  4025 
  4026 * Algebra: formalization of classical algebra.  Intended as base for
  4027 any algebraic development in Isabelle.  Currently covers group theory
  4028 (up to Sylow's theorem) and ring theory (Universal Property of
  4029 Univariate Polynomials).  Contributions welcome;
  4030 
  4031 * GroupTheory: deleted, since its material has been moved to Algebra;
  4032 
  4033 * Complex: new directory of the complex numbers with numeric constants,
  4034 nonstandard complex numbers, and some complex analysis, standard and
  4035 nonstandard (Jacques Fleuriot);
  4036 
  4037 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4038 
  4039 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4040 Fleuriot);
  4041 
  4042 * Real/HahnBanach: updated and adapted to locales;
  4043 
  4044 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4045 Gray and Kramer);
  4046 
  4047 * UNITY: added the Meier-Sanders theory of progress sets;
  4048 
  4049 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4050 as abstract algorithms, instantiated to the JVM;
  4051 
  4052 * Bali: Java source language formalization. Type system, operational
  4053 semantics, axiomatic semantics. Supported language features:
  4054 classes, interfaces, objects,virtual methods, static methods,
  4055 static/instance fields, arrays, access modifiers, definite
  4056 assignment, exceptions.
  4057 
  4058 
  4059 *** ZF ***
  4060 
  4061 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4062 universe, etc.);
  4063 
  4064 * Main ZF: virtually all theories converted to new-style format;
  4065 
  4066 
  4067 *** ML ***
  4068 
  4069 * Pure: Tactic.prove provides sane interface for internal proofs;
  4070 omits the infamous "standard" operation, so this is more appropriate
  4071 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4072 
  4073 * Pure: improved error reporting of simprocs;
  4074 
  4075 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4076 up simprocs;
  4077 
  4078 
  4079 *** Document preparation ***
  4080 
  4081 * uses \par instead of \\ for line breaks in theory text. This may
  4082 shift some page breaks in large documents. To get the old behaviour
  4083 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4084 
  4085 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4086 other packages
  4087 
  4088 * \<euro> now needs package babel/greek instead of marvosym (which
  4089 broke \Rightarrow)
  4090 
  4091 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4092 textcomp package)
  4093 
  4094 
  4095 
  4096 New in Isabelle2002 (March 2002)
  4097 --------------------------------
  4098 
  4099 *** Document preparation ***
  4100 
  4101 * greatly simplified document preparation setup, including more
  4102 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4103 instructive isatool mkdir; users should basically be able to get
  4104 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4105 users may run a separate document processing stage manually like this:
  4106 "isatool usedir -D output HOL Test && isatool document Test/output";
  4107 
  4108 * theory dependency graph may now be incorporated into documents;
  4109 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4110 with \includegraphics of LaTeX;
  4111 
  4112 * proper spacing of consecutive markup elements, especially text
  4113 blocks after section headings;
  4114 
  4115 * support bold style (for single symbols only), input syntax is like
  4116 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4117 
  4118 * \<bullet> is now output as bold \cdot by default, which looks much
  4119 better in printed text;
  4120 
  4121 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4122 note that these symbols are currently unavailable in Proof General /
  4123 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4124 
  4125 * isatool latex no longer depends on changed TEXINPUTS, instead
  4126 isatool document copies the Isabelle style files to the target
  4127 location;
  4128 
  4129 
  4130 *** Isar ***
  4131 
  4132 * Pure/Provers: improved proof by cases and induction;
  4133   - 'case' command admits impromptu naming of parameters (such as
  4134     "case (Suc n)");
  4135   - 'induct' method divinates rule instantiation from the inductive
  4136     claim; no longer requires excessive ?P bindings for proper
  4137     instantiation of cases;
  4138   - 'induct' method properly enumerates all possibilities of set/type
  4139     rules; as a consequence facts may be also passed through *type*
  4140     rules without further ado;
  4141   - 'induct' method now derives symbolic cases from the *rulified*
  4142     rule (before it used to rulify cases stemming from the internal
  4143     atomized version); this means that the context of a non-atomic
  4144     statement becomes is included in the hypothesis, avoiding the
  4145     slightly cumbersome show "PROP ?case" form;
  4146   - 'induct' may now use elim-style induction rules without chaining
  4147     facts, using ``missing'' premises from the goal state; this allows
  4148     rules stemming from inductive sets to be applied in unstructured
  4149     scripts, while still benefitting from proper handling of non-atomic
  4150     statements; NB: major inductive premises need to be put first, all
  4151     the rest of the goal is passed through the induction;
  4152   - 'induct' proper support for mutual induction involving non-atomic
  4153     rule statements (uses the new concept of simultaneous goals, see
  4154     below);
  4155   - append all possible rule selections, but only use the first
  4156     success (no backtracking);
  4157   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4158   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4159   - added 'print_induct_rules' (covered by help item in recent Proof
  4160     General versions);
  4161   - moved induct/cases attributes to Pure, methods to Provers;
  4162   - generic method setup instantiated for FOL and HOL;
  4163 
  4164 * Pure: support multiple simultaneous goal statements, for example
  4165 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4166 meta-level mechanism, this acts as if several individual goals had
  4167 been stated separately; in particular common proof methods need to be
  4168 repeated in order to cover all claims; note that a single elimination
  4169 step is *not* sufficient to establish the two conjunctions, so this
  4170 fails:
  4171 
  4172   assume "A & B" then have A and B ..   (*".." fails*)
  4173 
  4174 better use "obtain" in situations as above; alternative refer to
  4175 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4176 
  4177 * Pure: proper integration with ``locales''; unlike the original
  4178 version by Florian Kammller, Isar locales package high-level proof
  4179 contexts rather than raw logical ones (e.g. we admit to include
  4180 attributes everywhere); operations on locales include merge and
  4181 rename; support for implicit arguments (``structures''); simultaneous
  4182 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4183 some examples;
  4184 
  4185 * Pure: the following commands have been ``localized'', supporting a
  4186 target locale specification "(in name)": 'lemma', 'theorem',
  4187 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4188 stored both within the locale and at the theory level (exported and
  4189 qualified by the locale name);
  4190 
  4191 * Pure: theory goals may now be specified in ``long'' form, with
  4192 ad-hoc contexts consisting of arbitrary locale elements. for example
  4193 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4194 definitions may be given, too); the result is a meta-level rule with
  4195 the context elements being discharged in the obvious way;
  4196 
  4197 * Pure: new proof command 'using' allows to augment currently used
  4198 facts after a goal statement ('using' is syntactically analogous to
  4199 'apply', but acts on the goal's facts only); this allows chained facts
  4200 to be separated into parts given before and after a claim, as in
  4201 ``from a and b have C using d and e <proof>'';
  4202 
  4203 * Pure: renamed "antecedent" case to "rule_context";
  4204 
  4205 * Pure: new 'judgment' command records explicit information about the
  4206 object-logic embedding (used by several tools internally); no longer
  4207 use hard-wired "Trueprop";
  4208 
  4209 * Pure: added 'corollary' command;
  4210 
  4211 * Pure: fixed 'token_translation' command;
  4212 
  4213 * Pure: removed obsolete 'exported' attribute;
  4214 
  4215 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4216 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4217 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4218 
  4219 * Pure: method 'atomize' presents local goal premises as object-level
  4220 statements (atomic meta-level propositions); setup controlled via
  4221 rewrite rules declarations of 'atomize' attribute; example
  4222 application: 'induct' method with proper rule statements in improper
  4223 proof *scripts*;
  4224 
  4225 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4226 now consider the syntactic context of assumptions, giving a better
  4227 chance to get type-inference of the arguments right (this is
  4228 especially important for locales);
  4229 
  4230 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4231 mode;
  4232 
  4233 * Pure/obtain: the formal conclusion "thesis", being marked as
  4234 ``internal'', may no longer be reference directly in the text;
  4235 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4236 situations;
  4237 
  4238 * Pure: generic 'sym' attribute which declares a rule both as pure
  4239 'elim?' and for the 'symmetric' operation;
  4240 
  4241 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4242 text; the fixed correlation with particular command syntax has been
  4243 discontinued;
  4244 
  4245 * Pure: new method 'rules' is particularly well-suited for proof
  4246 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4247 but often produces more compact proof terms with less detours;
  4248 
  4249 * Pure/Provers/classical: simplified integration with pure rule
  4250 attributes and methods; the classical "intro?/elim?/dest?"
  4251 declarations coincide with the pure ones; the "rule" method no longer
  4252 includes classically swapped intros; "intro" and "elim" methods no
  4253 longer pick rules from the context; also got rid of ML declarations
  4254 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4255 INCOMPATIBILITY;
  4256 
  4257 * Provers/classical: attribute 'swapped' produces classical inversions
  4258 of introduction rules;
  4259 
  4260 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4261 rules instead of full simplifier context; 'iff' attribute handles
  4262 conditional rules;
  4263 
  4264 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4265 
  4266 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4267 "(permissive)" option to recover old behavior;
  4268 
  4269 * HOL: 'inductive' no longer features separate (collective) attributes
  4270 for 'intros' (was found too confusing);
  4271 
  4272 * HOL: properly declared induction rules less_induct and
  4273 wf_induct_rule;
  4274 
  4275 
  4276 *** HOL ***
  4277 
  4278 * HOL: moved over to sane numeral syntax; the new policy is as
  4279 follows:
  4280 
  4281   - 0 and 1 are polymorphic constants, which are defined on any
  4282   numeric type (nat, int, real etc.);
  4283 
  4284   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4285   binary representation internally;
  4286 
  4287   - type nat has special constructor Suc, and generally prefers Suc 0
  4288   over 1::nat and Suc (Suc 0) over 2::nat;
  4289 
  4290 This change may cause significant problems of INCOMPATIBILITY; here
  4291 are some hints on converting existing sources:
  4292 
  4293   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4294   entities, so expressions involving "-" (unary or binary minus) need
  4295   to be spaced properly;
  4296 
  4297   - existing occurrences of "1" may need to be constraint "1::nat" or
  4298   even replaced by Suc 0; similar for old "2";
  4299 
  4300   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4301 
  4302   - remove all special provisions on numerals in proofs;
  4303 
  4304 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4305 representation (depends on bin_arith_simps in the default context);
  4306 
  4307 * HOL: symbolic syntax for x^2 (numeral 2);
  4308 
  4309 * HOL: the class of all HOL types is now called "type" rather than
  4310 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4311 in axclass/classes, instance/arities, and (usually rare) occurrences
  4312 in typings (of consts etc.); internally the class is called
  4313 "HOL.type", ML programs should refer to HOLogic.typeS;
  4314 
  4315 * HOL/record package improvements:
  4316   - new derived operations "fields" to build a partial record section,
  4317     "extend" to promote a fixed record to a record scheme, and
  4318     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4319     declared as simp by default;
  4320   - shared operations ("more", "fields", etc.) now need to be always
  4321     qualified) --- potential INCOMPATIBILITY;
  4322   - removed "make_scheme" operations (use "make" with "extend") --
  4323     INCOMPATIBILITY;
  4324   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4325   - provides cases/induct rules for use with corresponding Isar
  4326     methods (for concrete records, record schemes, concrete more
  4327     parts, and schematic more parts -- in that order);
  4328   - internal definitions directly based on a light-weight abstract
  4329     theory of product types over typedef rather than datatype;
  4330 
  4331 * HOL: generic code generator for generating executable ML code from
  4332 specifications; specific support for HOL constructs such as inductive
  4333 datatypes and sets, as well as recursive functions; can be invoked
  4334 via 'generate_code' theory section;
  4335 
  4336 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4337 
  4338 * HOL: consolidated and renamed several theories.  In particular:
  4339         Ord.thy has been absorbed into HOL.thy
  4340         String.thy has been absorbed into List.thy
  4341 
  4342 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4343 (beware of argument permutation!);
  4344 
  4345 * HOL: linorder_less_split superseded by linorder_cases;
  4346 
  4347 * HOL/List: "nodups" renamed to "distinct";
  4348 
  4349 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4350 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4351   - Ex_def has changed, now need to use some_eq_ex
  4352 
  4353 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4354 in this (rare) case use:
  4355 
  4356   delSWrapper "split_all_tac"
  4357   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4358 
  4359 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4360 MAY FAIL;
  4361 
  4362 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4363 Isabelle's type classes, ^ on functions and relations has too general
  4364 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4365 necessary to attach explicit type constraints;
  4366 
  4367 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4368 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4369 renamed accordingly (eg "compI" -> "rel_compI").
  4370 
  4371 * HOL: syntax translations now work properly with numerals and records
  4372 expressions;
  4373 
  4374 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4375 of "lam" -- INCOMPATIBILITY;
  4376 
  4377 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4378 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4379 renamed "Product_Type.unit";
  4380 
  4381 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4382 
  4383 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4384 the "cases" method);
  4385 
  4386 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4387 Florian Kammller);
  4388 
  4389 * HOL/IMP: updated and converted to new-style theory format; several
  4390 parts turned into readable document, with proper Isar proof texts and
  4391 some explanations (by Gerwin Klein);
  4392 
  4393 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4394 
  4395 * HOL-Hyperreal is now a logic image;
  4396 
  4397 
  4398 *** HOLCF ***
  4399 
  4400 * Isar: consts/constdefs supports mixfix syntax for continuous
  4401 operations;
  4402 
  4403 * Isar: domain package adapted to new-style theory format, e.g. see
  4404 HOLCF/ex/Dnat.thy;
  4405 
  4406 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4407 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4408 lift.induct_tac, always use UU instead of Undef;
  4409 
  4410 * HOLCF/IMP: updated and converted to new-style theory;
  4411 
  4412 
  4413 *** ZF ***
  4414 
  4415 * Isar: proper integration of logic-specific tools and packages,
  4416 including theory commands '(co)inductive', '(co)datatype',
  4417 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4418 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4419 
  4420 * theory Main no longer includes AC; for the Axiom of Choice, base
  4421 your theory on Main_ZFC;
  4422 
  4423 * the integer library now covers quotients and remainders, with many
  4424 laws relating division to addition, multiplication, etc.;
  4425 
  4426 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4427 typeless version of the formalism;
  4428 
  4429 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4430 format;
  4431 
  4432 * ZF/Induct: new directory for examples of inductive definitions,
  4433 including theory Multiset for multiset orderings; converted to
  4434 new-style theory format;
  4435 
  4436 * ZF: many new theorems about lists, ordinals, etc.;
  4437 
  4438 
  4439 *** General ***
  4440 
  4441 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4442 variable proof controls level of detail: 0 = no proofs (only oracle
  4443 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4444 also ref manual for further ML interfaces;
  4445 
  4446 * Pure/axclass: removed obsolete ML interface
  4447 goal_subclass/goal_arity;
  4448 
  4449 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4450 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4451 separate tokens, so expressions involving minus need to be spaced
  4452 properly;
  4453 
  4454 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4455 rather than "infixl" or "infixr";
  4456 
  4457 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4458 sort constraint specifications in type inference; e.g. "x::_::foo"
  4459 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4460 type variable);
  4461 
  4462 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4463 control output of nested => (types); the default behavior is
  4464 "type_brackets";
  4465 
  4466 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4467 tokens into AST constants;
  4468 
  4469 * Pure/syntax: prefer later declarations of translations and print
  4470 translation functions; potential INCOMPATIBILITY: need to reverse
  4471 multiple declarations for same syntax element constant;
  4472 
  4473 * Pure/show_hyps reset by default (in accordance to existing Isar
  4474 practice);
  4475 
  4476 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4477 addSafter;
  4478 
  4479 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4480 as well;
  4481 
  4482 * system: tested support for MacOS X; should be able to get Isabelle +
  4483 Proof General to work in a plain Terminal after installing Poly/ML
  4484 (e.g. from the Isabelle distribution area) and GNU bash alone
  4485 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4486 support requires further installations, e.g. from
  4487 http://fink.sourceforge.net/);
  4488 
  4489 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4490 
  4491 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4492 of 40 MB), cf. ML_OPTIONS;
  4493 
  4494 * system: Proof General keywords specification is now part of the
  4495 Isabelle distribution (see etc/isar-keywords.el);
  4496 
  4497 * system: support for persistent Proof General sessions (refrain from
  4498 outdating all loaded theories on startup); user may create writable
  4499 logic images like this: ``isabelle -q HOL Test'';
  4500 
  4501 * system: smart selection of Isabelle process versus Isabelle
  4502 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4503 run both "isabelle" and "Isabelle" even if file names are badly
  4504 damaged (executable inspects the case of the first letter of its own
  4505 name); added separate "isabelle-process" and "isabelle-interface";
  4506 
  4507 * system: refrain from any attempt at filtering input streams; no
  4508 longer support ``8bit'' encoding of old isabelle font, instead proper
  4509 iso-latin characters may now be used; the related isatools
  4510 "symbolinput" and "nonascii" have disappeared as well;
  4511 
  4512 * system: removed old "xterm" interface (the print modes "xterm" and
  4513 "xterm_color" are still available for direct use in a suitable
  4514 terminal);
  4515 
  4516 
  4517 
  4518 New in Isabelle99-2 (February 2001)
  4519 -----------------------------------
  4520 
  4521 *** Overview of INCOMPATIBILITIES ***
  4522 
  4523 * HOL: please note that theories in the Library and elsewhere often use the
  4524 new-style (Isar) format; to refer to their theorems in an ML script you must
  4525 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4526 
  4527 * HOL: inductive package no longer splits induction rule aggressively,
  4528 but only as far as specified by the introductions given; the old
  4529 format may be recovered via ML function complete_split_rule or attribute
  4530 'split_rule (complete)';
  4531 
  4532 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4533 gfp_Tarski to gfp_unfold;
  4534 
  4535 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4536 
  4537 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4538 relation); infix "^^" has been renamed "``"; infix "``" has been
  4539 renamed "`"; "univalent" has been renamed "single_valued";
  4540 
  4541 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4542 operation;
  4543 
  4544 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4545 
  4546 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4547 
  4548 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4549 consequence, it is no longer monotonic wrt. the local goal context
  4550 (which is now passed through the inductive cases);
  4551 
  4552 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4553 \<gg> to \<ggreater>;
  4554 
  4555 
  4556 *** Document preparation ***
  4557 
  4558 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4559 available: are "it" for near math-mode best-style output, "sl" for
  4560 slanted text style, and "tt" for plain type-writer; if no
  4561 \isabellestyle command is given, output is according to slanted
  4562 type-writer);
  4563 
  4564 * support sub/super scripts (for single symbols only), input syntax is
  4565 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4566 
  4567 * some more standard symbols; see Appendix A of the system manual for
  4568 the complete list of symbols defined in isabellesym.sty;
  4569 
  4570 * improved isabelle style files; more abstract symbol implementation
  4571 (should now use \isamath{...} and \isatext{...} in custom symbol
  4572 definitions);
  4573 
  4574 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4575 state; Note that presentation of goal states does not conform to
  4576 actual human-readable proof documents.  Please do not include goal
  4577 states into document output unless you really know what you are doing!
  4578 
  4579 * proper indentation of antiquoted output with proportional LaTeX
  4580 fonts;
  4581 
  4582 * no_document ML operator temporarily disables LaTeX document
  4583 generation;
  4584 
  4585 * isatool unsymbolize tunes sources for plain ASCII communication;
  4586 
  4587 
  4588 *** Isar ***
  4589 
  4590 * Pure: Isar now suffers initial goal statements to contain unbound
  4591 schematic variables (this does not conform to actual readable proof
  4592 documents, due to unpredictable outcome and non-compositional proof
  4593 checking); users who know what they are doing may use schematic goals
  4594 for Prolog-style synthesis of proven results;
  4595 
  4596 * Pure: assumption method (an implicit finishing) now handles actual
  4597 rules as well;
  4598 
  4599 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4600 initial goal, declare "that" only as Pure intro (only for single
  4601 steps); the "that" rule assumption may now be involved in implicit
  4602 finishing, thus ".." becomes a feasible for trivial obtains;
  4603 
  4604 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4605 instance proofs may be performed by "..";
  4606 
  4607 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4608 statements as well;
  4609 
  4610 * Pure: more robust selection of calculational rules;
  4611 
  4612 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4613 rule (as well as the assumption rule);
  4614 
  4615 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4616 lemmas, using the graph browser tool;
  4617 
  4618 * Pure: predict failure of "show" in interactive mode;
  4619 
  4620 * Pure: 'thms_containing' now takes actual terms as arguments;
  4621 
  4622 * HOL: improved method 'induct' --- now handles non-atomic goals
  4623 (potential INCOMPATIBILITY); tuned error handling;
  4624 
  4625 * HOL: cases and induct rules now provide explicit hints about the
  4626 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4627 any remaining facts are inserted into the goal verbatim;
  4628 
  4629 * HOL: local contexts (aka cases) may now contain term bindings as
  4630 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4631 the result to be shown in each case;
  4632 
  4633 * HOL: added 'recdef_tc' command;
  4634 
  4635 * isatool convert assists in eliminating legacy ML scripts;
  4636 
  4637 
  4638 *** HOL ***
  4639 
  4640 * HOL/Library: a collection of generic theories to be used together
  4641 with main HOL; the theory loader path already includes this directory
  4642 by default; the following existing theories have been moved here:
  4643 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4644 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4645 
  4646 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4647 modelling and verification task performed in Isabelle/HOL +
  4648 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4649 
  4650 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4651 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4652 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4653 'domain', this makes the theory consistent with mathematical
  4654 literature;
  4655 
  4656 * HOL basics: added overloaded operations "inverse" and "divide"
  4657 (infix "/"), syntax for generic "abs" operation, generic summation
  4658 operator \<Sum>;
  4659 
  4660 * HOL/typedef: simplified package, provide more useful rules (see also
  4661 HOL/subset.thy);
  4662 
  4663 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4664 now expressed as a proper nested rule (old-style tactic scripts may
  4665 require atomize_strip_tac to cope with non-atomic premises);
  4666 
  4667 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4668 to "split_conv" (old name still available for compatibility);
  4669 
  4670 * HOL: improved concrete syntax for strings (e.g. allows translation
  4671 rules with string literals);
  4672 
  4673 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4674  and Fleuriot's mechanization of analysis, including the transcendental
  4675  functions for the reals;
  4676 
  4677 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4678 
  4679 
  4680 *** CTT ***
  4681 
  4682 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4683 "lam" is displayed as TWO lambda-symbols
  4684 
  4685 * CTT: theory Main now available, containing everything (that is, Bool
  4686 and Arith);
  4687 
  4688 
  4689 *** General ***
  4690 
  4691 * Pure: the Simplifier has been implemented properly as a derived rule
  4692 outside of the actual kernel (at last!); the overall performance
  4693 penalty in practical applications is about 50%, while reliability of
  4694 the Isabelle inference kernel has been greatly improved;
  4695 
  4696 * print modes "brackets" and "no_brackets" control output of nested =>
  4697 (types) and ==> (props); the default behaviour is "brackets";
  4698 
  4699 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4700 as assumptions as well;
  4701 
  4702 * system: support Poly/ML 4.0;
  4703 
  4704 * system: isatool install handles KDE version 1 or 2;
  4705 
  4706 
  4707 
  4708 New in Isabelle99-1 (October 2000)
  4709 ----------------------------------
  4710 
  4711 *** Overview of INCOMPATIBILITIES ***
  4712 
  4713 * HOL: simplification of natural numbers is much changed; to partly
  4714 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4715 issue the following ML commands:
  4716 
  4717   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4718   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4719 
  4720 * HOL: simplification no longer dives into case-expressions; this is
  4721 controlled by "t.weak_case_cong" for each datatype t;
  4722 
  4723 * HOL: nat_less_induct renamed to less_induct;
  4724 
  4725 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4726 fixsome to patch .thy and .ML sources automatically;
  4727 
  4728   select_equality  -> some_equality
  4729   select_eq_Ex     -> some_eq_ex
  4730   selectI2EX       -> someI2_ex
  4731   selectI2         -> someI2
  4732   selectI          -> someI
  4733   select1_equality -> some1_equality
  4734   Eps_sym_eq       -> some_sym_eq_trivial
  4735   Eps_eq           -> some_eq_trivial
  4736 
  4737 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4738 
  4739 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4740 instead);
  4741 
  4742 * HOL: the recursion equations generated by 'recdef' are now called
  4743 f.simps instead of f.rules;
  4744 
  4745 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4746 
  4747 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4748 sometimes be needed;
  4749 
  4750 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4751 
  4752 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4753 
  4754 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4755 product is now "<*>" instead of "Times"; the lexicographic product is
  4756 now "<*lex*>" instead of "**";
  4757 
  4758 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4759 of main HOL, but was unused); better use HOL's datatype package;
  4760 
  4761 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4762 the old syntax may be recovered as follows:
  4763 
  4764   syntax (symbols)
  4765     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4766       (infixl "\\<oplus>" 100)
  4767 
  4768 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4769 
  4770 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4771 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4772 internally;
  4773 
  4774 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4775 changed from A/r to A//r;
  4776 
  4777 * ZF: new treatment of arithmetic (nat & int) may break some old
  4778 proofs;
  4779 
  4780 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4781 rulify -> rule_format, elimify -> elim_format, ...);
  4782 
  4783 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4784 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4785 should have to change intro!! to intro? only); replaced "delrule" by
  4786 "rule del";
  4787 
  4788 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4789 
  4790 * Provers: strengthened force_tac by using new first_best_tac;
  4791 
  4792 * LaTeX document preparation: several changes of isabelle.sty (see
  4793 lib/texinputs);
  4794 
  4795 
  4796 *** Document preparation ***
  4797 
  4798 * formal comments (text blocks etc.) in new-style theories may now
  4799 contain antiquotations of thm/prop/term/typ/text to be presented
  4800 according to latex print mode; concrete syntax is like this:
  4801 @{term[show_types] "f(x) = a + x"};
  4802 
  4803 * isatool mkdir provides easy setup of Isabelle session directories,
  4804 including proper document sources;
  4805 
  4806 * generated LaTeX sources are now deleted after successful run
  4807 (isatool document -c); may retain a copy somewhere else via -D option
  4808 of isatool usedir;
  4809 
  4810 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4811 style files, achieving self-contained LaTeX sources and simplifying
  4812 LaTeX debugging;
  4813 
  4814 * old-style theories now produce (crude) LaTeX output as well;
  4815 
  4816 * browser info session directories are now self-contained (may be put
  4817 on WWW server seperately); improved graphs of nested sessions; removed
  4818 graph for 'all sessions';
  4819 
  4820 * several improvements in isabelle style files; \isabellestyle{it}
  4821 produces fake math mode output; \isamarkupheader is now \section by
  4822 default; see lib/texinputs/isabelle.sty etc.;
  4823 
  4824 
  4825 *** Isar ***
  4826 
  4827 * Isar/Pure: local results and corresponding term bindings are now
  4828 subject to Hindley-Milner polymorphism (similar to ML); this
  4829 accommodates incremental type-inference very nicely;
  4830 
  4831 * Isar/Pure: new derived language element 'obtain' supports
  4832 generalized existence reasoning;
  4833 
  4834 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4835 support accumulation of results, without applying any rules yet;
  4836 useful to collect intermediate results without explicit name
  4837 references, and for use with transitivity rules with more than 2
  4838 premises;
  4839 
  4840 * Isar/Pure: scalable support for case-analysis type proofs: new
  4841 'case' language element refers to local contexts symbolically, as
  4842 produced by certain proof methods; internally, case names are attached
  4843 to theorems as "tags";
  4844 
  4845 * Isar/Pure: theory command 'hide' removes declarations from
  4846 class/type/const name spaces;
  4847 
  4848 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4849 indicate potential overloading;
  4850 
  4851 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4852 
  4853 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4854 "{a,b,c}" instead of {a,b,c};
  4855 
  4856 * Isar/Pure now provides its own version of intro/elim/dest
  4857 attributes; useful for building new logics, but beware of confusion
  4858 with the version in Provers/classical;
  4859 
  4860 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4861 case name 'antecedent';
  4862 
  4863 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4864 to the current context is now done automatically);
  4865 
  4866 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4867 for definining proof methods in ML;
  4868 
  4869 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4870 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4871 most cases, one should have to change intro!! to intro? only);
  4872 replaced "delrule" by "rule del";
  4873 
  4874 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4875 'symmetric' attribute (the latter supercedes [RS sym]);
  4876 
  4877 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4878 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4879 well (including splits);
  4880 
  4881 * Isar/Provers: Simplifier and Classical methods now support all kind
  4882 of modifiers used in the past, including 'cong', 'iff', etc.
  4883 
  4884 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4885 of Simplifier and Classical reasoner);
  4886 
  4887 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4888 now support named cases; major packages (inductive, datatype, primrec,
  4889 recdef) support case names and properly name parameters;
  4890 
  4891 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4892 monotonicity conditions are extracted to be proven at end of
  4893 calculations;
  4894 
  4895 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4896 method anyway;
  4897 
  4898 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4899 split_if split_if_asm; datatype package provides theorems foo.splits =
  4900 foo.split foo.split_asm for each datatype;
  4901 
  4902 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4903 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4904 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4905 use "(cases (simplified))" method in proper proof texts);
  4906 
  4907 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4908 
  4909 * Isar: names of theorems etc. may be natural numbers as well;
  4910 
  4911 * Isar: 'pr' command: optional arguments for goals_limit and
  4912 ProofContext.prems_limit; no longer prints theory contexts, but only
  4913 proof states;
  4914 
  4915 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4916 additional print modes to be specified; e.g. "pr(latex)" will print
  4917 proof state according to the Isabelle LaTeX style;
  4918 
  4919 * Isar: improved support for emulating tactic scripts, including proof
  4920 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4921 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4922 (for HOL datatypes);
  4923 
  4924 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4925 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4926 'proof method scripts' have to be in depth-first order;
  4927 
  4928 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4929 
  4930 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4931 should instead use individual commands for printing items
  4932 (print_commands, print_methods etc.);
  4933 
  4934 * Isar: added 'nothing' --- the empty list of theorems;
  4935 
  4936 
  4937 *** HOL ***
  4938 
  4939 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4940 corresponding virtual machine and a specification of its bytecode
  4941 verifier and a lightweight bytecode verifier, including proofs of
  4942 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4943 Cornelia Pusch (see also the homepage of project Bali at
  4944 http://isabelle.in.tum.de/Bali/);
  4945 
  4946 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4947 Clemens Ballarin;
  4948 
  4949 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4950 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4951 Rasmussen;
  4952 
  4953 * HOL/Lattice: fundamental concepts of lattice theory and order
  4954 structures, including duals, properties of bounds versus algebraic
  4955 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4956 Theorem for complete lattices etc.; may also serve as a demonstration
  4957 for abstract algebraic reasoning using axiomatic type classes, and
  4958 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4959 
  4960 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4961 von Oheimb;
  4962 
  4963 * HOL/IMPP: extension of IMP with local variables and mutually
  4964 recursive procedures, by David von Oheimb;
  4965 
  4966 * HOL/Lambda: converted into new-style theory and document;
  4967 
  4968 * HOL/ex/Multiquote: example of multiple nested quotations and
  4969 anti-quotations -- basically a generalized version of de-Bruijn
  4970 representation; very useful in avoiding lifting of operations;
  4971 
  4972 * HOL/record: added general record equality rule to simpset; fixed
  4973 select-update simplification procedure to handle extended records as
  4974 well; admit "r" as field name;
  4975 
  4976 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4977 other numeric types and also as the identity of groups, rings, etc.;
  4978 
  4979 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4980 Types nat and int belong to this axclass;
  4981 
  4982 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4983    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4984    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4985   two terms #m*u and #n*u are replaced by #(m+n)*u
  4986     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4987   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4988     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4989 
  4990 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4991 powerful prover for predicate logic but knows nothing of clasets; see
  4992 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4993 
  4994 * HOL: new version of "case_tac" subsumes both boolean case split and
  4995 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4996 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4997 
  4998 * HOL: simplification no longer dives into case-expressions: only the
  4999 selector expression is simplified, but not the remaining arms; to
  5000 enable full simplification of case-expressions for datatype t, you may
  5001 remove t.weak_case_cong from the simpset, either globally (Delcongs
  5002 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  5003 
  5004 * HOL/recdef: the recursion equations generated by 'recdef' for
  5005 function 'f' are now called f.simps instead of f.rules; if all
  5006 termination conditions are proved automatically, these simplification
  5007 rules are added to the simpset, as in primrec; rules may be named
  5008 individually as well, resulting in a separate list of theorems for
  5009 each equation;
  5010 
  5011 * HOL/While is a new theory that provides a while-combinator. It
  5012 permits the definition of tail-recursive functions without the
  5013 provision of a termination measure. The latter is necessary once the
  5014 invariant proof rule for while is applied.
  5015 
  5016 * HOL: new (overloaded) notation for the set of elements below/above
  5017 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5018 
  5019 * HOL: theorems impI, allI, ballI bound as "strip";
  5020 
  5021 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5022 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5023 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5024 
  5025 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5026 
  5027 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5028 main HOL, but was unused);
  5029 
  5030 * HOL: fewer consts declared as global (e.g. have to refer to
  5031 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5032 
  5033 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5034 in case of overlap with user translations (e.g. judgements over
  5035 tuples); (note that the underlying logical represenation is still
  5036 bogus);
  5037 
  5038 
  5039 *** ZF ***
  5040 
  5041 * ZF: simplification automatically cancels common terms in arithmetic
  5042 expressions over nat and int;
  5043 
  5044 * ZF: new treatment of nat to minimize type-checking: all operators
  5045 coerce their operands to a natural number using the function natify,
  5046 making the algebraic laws unconditional;
  5047 
  5048 * ZF: as above, for int: operators coerce their operands to an integer
  5049 using the function intify;
  5050 
  5051 * ZF: the integer library now contains many of the usual laws for the
  5052 orderings, including $<=, and monotonicity laws for $+ and $*;
  5053 
  5054 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5055 simplification;
  5056 
  5057 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5058 to the simplifier and classical reasoner simultaneously;
  5059 
  5060 
  5061 *** General ***
  5062 
  5063 * Provers: blast_tac now handles actual object-logic rules as
  5064 assumptions; note that auto_tac uses blast_tac internally as well;
  5065 
  5066 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5067 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5068 
  5069 * Provers: delrules now handles destruct rules as well (no longer need
  5070 explicit make_elim);
  5071 
  5072 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5073   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5074 use instead the strong form,
  5075   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5076 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5077 from destruct-rules;
  5078 
  5079 * Provers: Simplifier.easy_setup provides a fast path to basic
  5080 Simplifier setup for new object-logics;
  5081 
  5082 * Pure: AST translation rules no longer require constant head on LHS;
  5083 
  5084 * Pure: improved name spaces: ambiguous output is qualified; support
  5085 for hiding of names;
  5086 
  5087 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5088 XSYMBOL_HOME; no longer need to do manual configuration in most
  5089 situations;
  5090 
  5091 * system: compression of ML heaps images may now be controlled via -c
  5092 option of isabelle and isatool usedir (currently only observed by
  5093 Poly/ML);
  5094 
  5095 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5096 useful for remote X11);
  5097 
  5098 * system: provide TAGS file for Isabelle sources;
  5099 
  5100 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5101 order;
  5102 
  5103 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5104 timing flag supersedes proof_timing and Toplevel.trace;
  5105 
  5106 * ML: new combinators |>> and |>>> for incremental transformations
  5107 with secondary results (e.g. certain theory extensions):
  5108 
  5109 * ML: PureThy.add_defs gets additional argument to indicate potential
  5110 overloading (usually false);
  5111 
  5112 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5113 results;
  5114 
  5115 
  5116 
  5117 New in Isabelle99 (October 1999)
  5118 --------------------------------
  5119 
  5120 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5121 
  5122 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5123 are no longer simplified.  (This allows the simplifier to unfold recursive
  5124 functional programs.)  To restore the old behaviour, declare
  5125 
  5126     Delcongs [if_weak_cong];
  5127 
  5128 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5129 complement;
  5130 
  5131 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5132 
  5133 * HOL/datatype: mutual_induct_tac no longer exists --
  5134   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5135 
  5136 * HOL/typedef: fixed type inference for representing set; type
  5137 arguments now have to occur explicitly on the rhs as type constraints;
  5138 
  5139 * ZF: The con_defs part of an inductive definition may no longer refer
  5140 to constants declared in the same theory;
  5141 
  5142 * HOL, ZF: the function mk_cases, generated by the inductive
  5143 definition package, has lost an argument.  To simplify its result, it
  5144 uses the default simpset instead of a supplied list of theorems.
  5145 
  5146 * HOL/List: the constructors of type list are now Nil and Cons;
  5147 
  5148 * Simplifier: the type of the infix ML functions
  5149         setSSolver addSSolver setSolver addSolver
  5150 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5151 for packaging solvers. A solver is created via
  5152         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5153 where the string argument is only a comment.
  5154 
  5155 
  5156 *** Proof tools ***
  5157 
  5158 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5159 decision procedure for linear arithmetic. Currently it is used for
  5160 types `nat', `int', and `real' in HOL (see below); it can, should and
  5161 will be instantiated for other types and logics as well.
  5162 
  5163 * The simplifier now accepts rewrite rules with flexible heads, eg
  5164      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5165   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5166   matching.
  5167 
  5168 
  5169 *** General ***
  5170 
  5171 * New Isabelle/Isar subsystem provides an alternative to traditional
  5172 tactical theorem proving; together with the ProofGeneral/isar user
  5173 interface it offers an interactive environment for developing human
  5174 readable proof documents (Isar == Intelligible semi-automated
  5175 reasoning); for further information see isatool doc isar-ref,
  5176 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5177 
  5178 * improved and simplified presentation of theories: better HTML markup
  5179 (including colors), graph views in several sizes; isatool usedir now
  5180 provides a proper interface for user theories (via -P option); actual
  5181 document preparation based on (PDF)LaTeX is available as well (for
  5182 new-style theories only); see isatool doc system for more information;
  5183 
  5184 * native support for Proof General, both for classic Isabelle and
  5185 Isabelle/Isar;
  5186 
  5187 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5188 using the graph browser tool;
  5189 
  5190 * Isabelle manuals now also available as PDF;
  5191 
  5192 * theory loader rewritten from scratch (may not be fully
  5193 bug-compatible); old loadpath variable has been replaced by show_path,
  5194 add_path, del_path, reset_path functions; new operations such as
  5195 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5196 isatool doc ref);
  5197 
  5198 * improved isatool install: option -k creates KDE application icon,
  5199 option -p DIR installs standalone binaries;
  5200 
  5201 * added ML_PLATFORM setting (useful for cross-platform installations);
  5202 more robust handling of platform specific ML images for SML/NJ;
  5203 
  5204 * the settings environment is now statically scoped, i.e. it is never
  5205 created again in sub-processes invoked from isabelle, isatool, or
  5206 Isabelle;
  5207 
  5208 * path element specification '~~' refers to '$ISABELLE_HOME';
  5209 
  5210 * in locales, the "assumes" and "defines" parts may be omitted if
  5211 empty;
  5212 
  5213 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5214 long arrows);
  5215 
  5216 * new print_mode "HTML";
  5217 
  5218 * new flag show_tags controls display of tags of theorems (which are
  5219 basically just comments that may be attached by some tools);
  5220 
  5221 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5222 mode and goal output format:
  5223 
  5224 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5225 244c244
  5226 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5227 ---
  5228 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5229 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5230 181c181
  5231 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5232 ---
  5233 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5234 
  5235 * function bind_thms stores lists of theorems (cf. bind_thm);
  5236 
  5237 * new shorthand tactics ftac, eatac, datac, fatac;
  5238 
  5239 * qed (and friends) now accept "" as result name; in that case the
  5240 theorem is not stored, but proper checks and presentation of the
  5241 result still apply;
  5242 
  5243 * theorem database now also indexes constants "Trueprop", "all",
  5244 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5245 
  5246 
  5247 *** HOL ***
  5248 
  5249 ** HOL arithmetic **
  5250 
  5251 * There are now decision procedures for linear arithmetic over nat and
  5252 int:
  5253 
  5254 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5255 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5256 are treated as atomic; subformulae not involving type `nat' or `int'
  5257 are ignored; quantified subformulae are ignored unless they are
  5258 positive universal or negative existential. The tactic has to be
  5259 invoked by hand and can be a little bit slow. In particular, the
  5260 running time is exponential in the number of occurrences of `min' and
  5261 `max', and `-' on `nat'.
  5262 
  5263 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5264 (negated) (in)equalities among the premises and the conclusion into
  5265 account (i.e. no compound formulae) and does not know about `min' and
  5266 `max', and `-' on `nat'. It is fast and is used automatically by the
  5267 simplifier.
  5268 
  5269 NB: At the moment, these decision procedures do not cope with mixed
  5270 nat/int formulae where the two parts interact, such as `m < n ==>
  5271 int(m) < int(n)'.
  5272 
  5273 * HOL/Numeral provides a generic theory of numerals (encoded
  5274 efficiently as bit strings); setup for types nat/int/real is in place;
  5275 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5276 int, existing theories and proof scripts may require a few additional
  5277 type constraints;
  5278 
  5279 * integer division and remainder can now be performed on constant
  5280 arguments;
  5281 
  5282 * many properties of integer multiplication, division and remainder
  5283 are now available;
  5284 
  5285 * An interface to the Stanford Validity Checker (SVC) is available through the
  5286 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5287 are proved automatically.  SVC must be installed separately, and its results
  5288 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5289 invocation of the underlying oracle).  For SVC see
  5290   http://verify.stanford.edu/SVC
  5291 
  5292 * IsaMakefile: the HOL-Real target now builds an actual image;
  5293 
  5294 
  5295 ** HOL misc **
  5296 
  5297 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5298 (in Isabelle/Isar) -- by Gertrud Bauer;
  5299 
  5300 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5301 analysis for assembly languages with subtypes;
  5302 
  5303 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5304 -- avoids syntactic ambiguities and treats state, transition, and
  5305 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5306 changed syntax and (many) tactics;
  5307 
  5308 * HOL/inductive: Now also handles more general introduction rules such
  5309   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5310   theorems are now maintained within the theory (maintained via the
  5311   "mono" attribute);
  5312 
  5313 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5314   (using function types) such as
  5315 
  5316   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5317 
  5318 * HOL/record: record_simproc (part of the default simpset) takes care
  5319 of selectors applied to updated records; record_split_tac is no longer
  5320 part of the default claset; update_defs may now be removed from the
  5321 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5322 
  5323   claset_ref () := claset() addSWrapper record_split_wrapper;
  5324   Delsimprocs [record_simproc]
  5325 
  5326 * HOL/typedef: fixed type inference for representing set; type
  5327 arguments now have to occur explicitly on the rhs as type constraints;
  5328 
  5329 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5330 names rather than an ML expression;
  5331 
  5332 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5333 supplied later.  Program schemes can be defined, such as
  5334     "While B C s = (if B s then While B C (C s) else s)"
  5335 where the well-founded relation can be chosen after B and C have been given.
  5336 
  5337 * HOL/List: the constructors of type list are now Nil and Cons;
  5338 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5339 course, ML tools referring to List.list.op # etc. have to be adapted;
  5340 
  5341 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5342 disabled by default; run isabelle with option -m HOL to get back to
  5343 the original Gordon/HOL-style output;
  5344 
  5345 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5346 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5347 
  5348 * HOL basic syntax simplified (more orthogonal): all variants of
  5349 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5350 Eps operator is provided as well: "SOME x. P[x]";
  5351 
  5352 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5353 
  5354 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5355 thus available for user theories;
  5356 
  5357 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5358 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5359 time;
  5360 
  5361 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5362 several times and then mp;
  5363 
  5364 
  5365 *** LK ***
  5366 
  5367 * the notation <<...>> is now available as a notation for sequences of
  5368 formulas;
  5369 
  5370 * the simplifier is now installed
  5371 
  5372 * the axiom system has been generalized (thanks to Soren Heilmann)
  5373 
  5374 * the classical reasoner now has a default rule database
  5375 
  5376 
  5377 *** ZF ***
  5378 
  5379 * new primrec section allows primitive recursive functions to be given
  5380 directly (as in HOL) over datatypes and the natural numbers;
  5381 
  5382 * new tactics induct_tac and exhaust_tac for induction (or case
  5383 analysis) over datatypes and the natural numbers;
  5384 
  5385 * the datatype declaration of type T now defines the recursor T_rec;
  5386 
  5387 * simplification automatically does freeness reasoning for datatype
  5388 constructors;
  5389 
  5390 * automatic type-inference, with AddTCs command to insert new
  5391 type-checking rules;
  5392 
  5393 * datatype introduction rules are now added as Safe Introduction rules
  5394 to the claset;
  5395 
  5396 * the syntax "if P then x else y" is now available in addition to
  5397 if(P,x,y);
  5398 
  5399 
  5400 *** Internal programming interfaces ***
  5401 
  5402 * tuned simplifier trace output; new flag debug_simp;
  5403 
  5404 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5405 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5406 
  5407 * AxClass.axclass_tac lost the theory argument;
  5408 
  5409 * tuned current_goals_markers semantics: begin / end goal avoids
  5410 printing empty lines;
  5411 
  5412 * removed prs and prs_fn hook, which was broken because it did not
  5413 include \n in its semantics, forcing writeln to add one
  5414 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5415 string -> unit if you really want to output text without newline;
  5416 
  5417 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5418 plain output, interface builders may have to enable 'isabelle_font'
  5419 mode to get Isabelle font glyphs as before;
  5420 
  5421 * refined token_translation interface; INCOMPATIBILITY: output length
  5422 now of type real instead of int;
  5423 
  5424 * theory loader actions may be traced via new ThyInfo.add_hook
  5425 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5426 your own database of information attached to *whole* theories -- as
  5427 opposed to intra-theory data slots offered via TheoryDataFun;
  5428 
  5429 * proper handling of dangling sort hypotheses (at last!);
  5430 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5431 extra sort hypotheses that can be witnessed from the type signature;
  5432 the force_strip_shyps flag is gone, any remaining shyps are simply
  5433 left in the theorem (with a warning issued by strip_shyps_warning);
  5434 
  5435 
  5436 
  5437 New in Isabelle98-1 (October 1998)
  5438 ----------------------------------
  5439 
  5440 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5441 
  5442 * several changes of automated proof tools;
  5443 
  5444 * HOL: major changes to the inductive and datatype packages, including
  5445 some minor incompatibilities of theory syntax;
  5446 
  5447 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5448 called `inj_on';
  5449 
  5450 * HOL: removed duplicate thms in Arith:
  5451   less_imp_add_less  should be replaced by  trans_less_add1
  5452   le_imp_add_le      should be replaced by  trans_le_add1
  5453 
  5454 * HOL: unary minus is now overloaded (new type constraints may be
  5455 required);
  5456 
  5457 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5458 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5459 now taken as an integer constant.
  5460 
  5461 * Pure: ML function 'theory_of' renamed to 'theory';
  5462 
  5463 
  5464 *** Proof tools ***
  5465 
  5466 * Simplifier:
  5467   1. Asm_full_simp_tac is now more aggressive.
  5468      1. It will sometimes reorient premises if that increases their power to
  5469         simplify.
  5470      2. It does no longer proceed strictly from left to right but may also
  5471         rotate premises to achieve further simplification.
  5472      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5473      old Asm_full_simp_tac in that it does not rotate premises.
  5474   2. The simplifier now knows a little bit about nat-arithmetic.
  5475 
  5476 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5477 allows for selected deletion of wrappers, by introduction of names for
  5478 wrapper functionals.  This implies that addbefore, addSbefore,
  5479 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5480 and that adding two tactics with the same name overwrites the first
  5481 one (emitting a warning).
  5482   type wrapper = (int -> tactic) -> (int -> tactic)
  5483   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5484   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5485   delWrapper, delSWrapper: claset *  string            -> claset
  5486   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5487 
  5488 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5489 semantics; addbefore now affects only the unsafe part of step_tac
  5490 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5491 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5492 by Force_tac;
  5493 
  5494 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5495 compWrapper; added safe wrapper (and access functions for it);
  5496 
  5497 * HOL/split_all_tac is now much faster and fails if there is nothing
  5498 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5499 and the names of the automatically generated variables have changed.
  5500 split_all_tac has moved within claset() from unsafe wrappers to safe
  5501 wrappers, which means that !!-bound variables are split much more
  5502 aggressively, and safe_tac and clarify_tac now split such variables.
  5503 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5504 Note: the same holds for record_split_tac, which does the job of
  5505 split_all_tac for record fields.
  5506 
  5507 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5508 permanently to the default simpset using Addsplits just like
  5509 Addsimps. They can be removed via Delsplits just like
  5510 Delsimps. Lower-case versions are also available.
  5511 
  5512 * HOL/Simplifier: The rule split_if is now part of the default
  5513 simpset. This means that the simplifier will eliminate all occurrences
  5514 of if-then-else in the conclusion of a goal. To prevent this, you can
  5515 either remove split_if completely from the default simpset by
  5516 `Delsplits [split_if]' or remove it in a specific call of the
  5517 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5518 other case splitting rules to/from the default simpset: every datatype
  5519 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5520 t is the name of the datatype).
  5521 
  5522 * Classical reasoner / Simplifier combination: new force_tac (and
  5523 derivatives Force_tac, force) combines rewriting and classical
  5524 reasoning (and whatever other tools) similarly to auto_tac, but is
  5525 aimed to solve the given subgoal completely.
  5526 
  5527 
  5528 *** General ***
  5529 
  5530 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5531 and `goalw': the theory is no longer needed as an explicit argument -
  5532 the current theory context is used; assumptions are no longer returned
  5533 at the ML-level unless one of them starts with ==> or !!; it is
  5534 recommended to convert to these new commands using isatool fixgoal
  5535 (backup your sources first!);
  5536 
  5537 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5538 the current theory context, and 'theory' to lookup stored theories;
  5539 
  5540 * new theory section 'locale' for declaring constants, assumptions and
  5541 definitions that have local scope;
  5542 
  5543 * new theory section 'nonterminals' for purely syntactic types;
  5544 
  5545 * new theory section 'setup' for generic ML setup functions
  5546 (e.g. package initialization);
  5547 
  5548 * the distribution now includes Isabelle icons: see
  5549 lib/logo/isabelle-{small,tiny}.xpm;
  5550 
  5551 * isatool install - install binaries with absolute references to
  5552 ISABELLE_HOME/bin;
  5553 
  5554 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5555 
  5556 * print mode 'emacs' reserved for Isamode;
  5557 
  5558 * support multiple print (ast) translations per constant name;
  5559 
  5560 * theorems involving oracles are now printed with a suffixed [!];
  5561 
  5562 
  5563 *** HOL ***
  5564 
  5565 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5566 
  5567 * HOL/inductive package reorganized and improved: now supports mutual
  5568 definitions such as
  5569 
  5570   inductive EVEN ODD
  5571     intrs
  5572       null "0 : EVEN"
  5573       oddI "n : EVEN ==> Suc n : ODD"
  5574       evenI "n : ODD ==> Suc n : EVEN"
  5575 
  5576 new theorem list "elims" contains an elimination rule for each of the
  5577 recursive sets; inductive definitions now handle disjunctive premises
  5578 correctly (also ZF);
  5579 
  5580 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5581 "mutual_induct" no longer exists - the induction rule is always
  5582 contained in "induct";
  5583 
  5584 
  5585 * HOL/datatype package re-implemented and greatly improved: now
  5586 supports mutually recursive datatypes such as
  5587 
  5588   datatype
  5589     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5590             | SUM ('a aexp) ('a aexp)
  5591             | DIFF ('a aexp) ('a aexp)
  5592             | NUM 'a
  5593   and
  5594     'a bexp = LESS ('a aexp) ('a aexp)
  5595             | AND ('a bexp) ('a bexp)
  5596             | OR ('a bexp) ('a bexp)
  5597 
  5598 as well as indirectly recursive datatypes such as
  5599 
  5600   datatype
  5601     ('a, 'b) term = Var 'a
  5602                   | App 'b ((('a, 'b) term) list)
  5603 
  5604 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5605 induction on mutually / indirectly recursive datatypes.
  5606 
  5607 Primrec equations are now stored in theory and can be accessed via
  5608 <function_name>.simps.
  5609 
  5610 INCOMPATIBILITIES:
  5611 
  5612   - Theories using datatypes must now have theory Datatype as an
  5613     ancestor.
  5614   - The specific <typename>.induct_tac no longer exists - use the
  5615     generic induct_tac instead.
  5616   - natE has been renamed to nat.exhaust - use exhaust_tac
  5617     instead of res_inst_tac ... natE. Note that the variable
  5618     names in nat.exhaust differ from the names in natE, this
  5619     may cause some "fragile" proofs to fail.
  5620   - The theorems split_<typename>_case and split_<typename>_case_asm
  5621     have been renamed to <typename>.split and <typename>.split_asm.
  5622   - Since default sorts of type variables are now handled correctly,
  5623     some datatype definitions may have to be annotated with explicit
  5624     sort constraints.
  5625   - Primrec definitions no longer require function name and type
  5626     of recursive argument.
  5627 
  5628 Consider using isatool fixdatatype to adapt your theories and proof
  5629 scripts to the new package (backup your sources first!).
  5630 
  5631 
  5632 * HOL/record package: considerably improved implementation; now
  5633 includes concrete syntax for record types, terms, updates; theorems
  5634 for surjective pairing and splitting !!-bound record variables; proof
  5635 support is as follows:
  5636 
  5637   1) standard conversions (selectors or updates applied to record
  5638 constructor terms) are part of the standard simpset;
  5639 
  5640   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5641 made part of standard simpset and claset via addIffs;
  5642 
  5643   3) a tactic for record field splitting (record_split_tac) is part of
  5644 the standard claset (addSWrapper);
  5645 
  5646 To get a better idea about these rules you may retrieve them via
  5647 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5648 the name of your record type.
  5649 
  5650 The split tactic 3) conceptually simplifies by the following rule:
  5651 
  5652   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5653 
  5654 Thus any record variable that is bound by meta-all will automatically
  5655 blow up into some record constructor term, consequently the
  5656 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5657 solve record problems automatically.
  5658 
  5659 
  5660 * reorganized the main HOL image: HOL/Integ and String loaded by
  5661 default; theory Main includes everything;
  5662 
  5663 * automatic simplification of integer sums and comparisons, using cancellation;
  5664 
  5665 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5666 
  5667 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5668 
  5669 * many new identities for unions, intersections, set difference, etc.;
  5670 
  5671 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5672 called split_if, split_split, split_sum_case and split_nat_case (to go
  5673 with add/delsplits);
  5674 
  5675 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5676 (?x::unit) = (); this is made part of the default simpset, which COULD
  5677 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5678 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5679 unit_abs_eta_conv is added in order to counter the effect of
  5680 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5681 %u.f();
  5682 
  5683 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5684 makes more sense);
  5685 
  5686 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5687   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5688   disjointness reasoning but breaking a few old proofs.
  5689 
  5690 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5691 to 'converse' from 'inverse' (for compatibility with ZF and some
  5692 literature);
  5693 
  5694 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5695 the well-founded relation;
  5696 
  5697 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5698     Compl A.  The "Compl" syntax remains available as input syntax for this
  5699     release ONLY.
  5700 
  5701 * HOL/Update: new theory of function updates:
  5702     f(a:=b) == %x. if x=a then b else f x
  5703 may also be iterated as in f(a:=b,c:=d,...);
  5704 
  5705 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5706 
  5707 * HOL/List:
  5708   - new function list_update written xs[i:=v] that updates the i-th
  5709     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5710   - new function `upt' written [i..j(] which generates the list
  5711     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5712     bound write [i..j], which is a shorthand for [i..j+1(].
  5713   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5714 
  5715 * HOL/Arith:
  5716   - removed 'pred' (predecessor) function;
  5717   - generalized some theorems about n-1;
  5718   - many new laws about "div" and "mod";
  5719   - new laws about greatest common divisors (see theory ex/Primes);
  5720 
  5721 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5722 instead of "inverse";
  5723 
  5724 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5725   of the multiset ordering;
  5726 
  5727 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5728   (not included by default);
  5729 
  5730 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5731 
  5732 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5733   programs, i.e. different program variables may have different types.
  5734 
  5735 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5736   [previously, this check worked only if the rewrite rule was unconditional]
  5737   Now rew can involve either definitions or equalities (either == or =).
  5738 
  5739 
  5740 *** ZF ***
  5741 
  5742 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5743   only the theorems proved on ZF.ML;
  5744 
  5745 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5746   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5747   disjointness reasoning but breaking a few old proofs.
  5748 
  5749 * ZF/Update: new theory of function updates
  5750     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5751   may also be iterated as in f(a:=b,c:=d,...);
  5752 
  5753 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5754 
  5755 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5756   [previously, this check worked only if the rewrite rule was unconditional]
  5757   Now rew can involve either definitions or equalities (either == or =).
  5758 
  5759 * case_tac provided for compatibility with HOL
  5760     (like the old excluded_middle_tac, but with subgoals swapped)
  5761 
  5762 
  5763 *** Internal programming interfaces ***
  5764 
  5765 * Pure: several new basic modules made available for general use, see
  5766 also src/Pure/README;
  5767 
  5768 * improved the theory data mechanism to support encapsulation (data
  5769 kind name replaced by private Object.kind, acting as authorization
  5770 key); new type-safe user interface via functor TheoryDataFun; generic
  5771 print_data function becomes basically useless;
  5772 
  5773 * removed global_names compatibility flag -- all theory declarations
  5774 are qualified by default;
  5775 
  5776 * module Pure/Syntax now offers quote / antiquote translation
  5777 functions (useful for Hoare logic etc. with implicit dependencies);
  5778 see HOL/ex/Antiquote for an example use;
  5779 
  5780 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5781 cterm -> thm;
  5782 
  5783 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5784 subgoal;
  5785 
  5786 * Display.print_goals function moved to Locale.print_goals;
  5787 
  5788 * standard print function for goals supports current_goals_markers
  5789 variable for marking begin of proof, end of proof, start of goal; the
  5790 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5791 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5792 for example;
  5793 
  5794 
  5795 
  5796 New in Isabelle98 (January 1998)
  5797 --------------------------------
  5798 
  5799 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5800 
  5801 * changed lexical syntax of terms / types: dots made part of long
  5802 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5803 
  5804 * simpset (and claset) reference variable replaced by functions
  5805 simpset / simpset_ref;
  5806 
  5807 * no longer supports theory aliases (via merge) and non-trivial
  5808 implicit merge of thms' signatures;
  5809 
  5810 * most internal names of constants changed due to qualified names;
  5811 
  5812 * changed Pure/Sequence interface (see Pure/seq.ML);
  5813 
  5814 
  5815 *** General Changes ***
  5816 
  5817 * hierachically structured name spaces (for consts, types, axms, thms
  5818 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5819 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5820 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5821 long_names for fully qualified output names; NOTE: ML programs
  5822 (special tactics, packages etc.) referring to internal names may have
  5823 to be adapted to cope with fully qualified names; in case of severe
  5824 backward campatibility problems try setting 'global_names' at compile
  5825 time to have enrything declared within a flat name space; one may also
  5826 fine tune name declarations in theories via the 'global' and 'local'
  5827 section;
  5828 
  5829 * reimplemented the implicit simpset and claset using the new anytype
  5830 data filed in signatures; references simpset:simpset ref etc. are
  5831 replaced by functions simpset:unit->simpset and
  5832 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5833 to patch your ML files accordingly;
  5834 
  5835 * HTML output now includes theory graph data for display with Java
  5836 applet or isatool browser; data generated automatically via isatool
  5837 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5838 
  5839 * defs may now be conditional; improved rewrite_goals_tac to handle
  5840 conditional equations;
  5841 
  5842 * defs now admits additional type arguments, using TYPE('a) syntax;
  5843 
  5844 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5845 creates a new theory node; implicit merge of thms' signatures is
  5846 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5847 transfer:theory->thm->thm in (rare) cases;
  5848 
  5849 * improved handling of draft signatures / theories; draft thms (and
  5850 ctyps, cterms) are automatically promoted to real ones;
  5851 
  5852 * slightly changed interfaces for oracles: admit many per theory, named
  5853 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5854 
  5855 * print_goals: optional output of const types (set show_consts and
  5856 show_types);
  5857 
  5858 * improved output of warnings (###) and errors (***);
  5859 
  5860 * subgoal_tac displays a warning if the new subgoal has type variables;
  5861 
  5862 * removed old README and Makefiles;
  5863 
  5864 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5865 
  5866 * removed obsolete init_pps and init_database;
  5867 
  5868 * deleted the obsolete tactical STATE, which was declared by
  5869     fun STATE tacfun st = tacfun st st;
  5870 
  5871 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5872 (which abbreviates $HOME);
  5873 
  5874 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5875 use isatool fixseq to adapt your ML programs (this works for fully
  5876 qualified references to the Sequence structure only!);
  5877 
  5878 * use_thy no longer requires writable current directory; it always
  5879 reloads .ML *and* .thy file, if either one is out of date;
  5880 
  5881 
  5882 *** Classical Reasoner ***
  5883 
  5884 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5885 tactics that use classical reasoning to simplify a subgoal without
  5886 splitting it into several subgoals;
  5887 
  5888 * Safe_tac: like safe_tac but uses the default claset;
  5889 
  5890 
  5891 *** Simplifier ***
  5892 
  5893 * added simplification meta rules:
  5894     (asm_)(full_)simplify: simpset -> thm -> thm;
  5895 
  5896 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5897 logics (again);
  5898 
  5899 * added prems argument to simplification procedures;
  5900 
  5901 * HOL, FOL, ZF: added infix function `addsplits':
  5902   instead of `<simpset> setloop (split_tac <thms>)'
  5903   you can simply write `<simpset> addsplits <thms>'
  5904 
  5905 
  5906 *** Syntax ***
  5907 
  5908 * TYPE('a) syntax for type reflection terms;
  5909 
  5910 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5911 
  5912 * pretty printer: changed order of mixfix annotation preference (again!);
  5913 
  5914 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5915 
  5916 
  5917 *** HOL ***
  5918 
  5919 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5920   with `addloop' of the simplifier to faciliate case splitting in premises.
  5921 
  5922 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5923 
  5924 * HOL/Auth: new protocol proofs including some for the Internet
  5925   protocol TLS;
  5926 
  5927 * HOL/Map: new theory of `maps' a la VDM;
  5928 
  5929 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5930 cancelling out common nat summands from =, <, <= (in)equalities, or
  5931 differences; simplification procedures nat_cancel_factor for
  5932 cancelling common factor from =, <, <= (in)equalities over natural
  5933 sums; nat_cancel contains both kinds of procedures, it is installed by
  5934 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5935 
  5936 * HOL/simplifier: terms of the form
  5937   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5938   are rewritten to
  5939   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5940   and those of the form
  5941   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5942   are rewritten to
  5943   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5944 
  5945 * HOL/datatype
  5946   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5947 
  5948   P(t_case f1 ... fn x) =
  5949      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5950         ...
  5951        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5952      )
  5953 
  5954   and a theorem `split_t_case_asm' of the form
  5955 
  5956   P(t_case f1 ... fn x) =
  5957     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5958         ...
  5959        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5960      )
  5961   which can be added to a simpset via `addsplits'. The existing theorems
  5962   expand_list_case and expand_option_case have been renamed to
  5963   split_list_case and split_option_case.
  5964 
  5965 * HOL/Arithmetic:
  5966   - `pred n' is automatically converted to `n-1'.
  5967     Users are strongly encouraged not to use `pred' any longer,
  5968     because it will disappear altogether at some point.
  5969   - Users are strongly encouraged to write "0 < n" rather than
  5970     "n ~= 0". Theorems and proof tools have been modified towards this
  5971     `standard'.
  5972 
  5973 * HOL/Lists:
  5974   the function "set_of_list" has been renamed "set" (and its theorems too);
  5975   the function "nth" now takes its arguments in the reverse order and
  5976   has acquired the infix notation "!" as in "xs!n".
  5977 
  5978 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5979 
  5980 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5981   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5982 
  5983 * HOL/record: extensible records with schematic structural subtyping
  5984 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5985 still lacks various theorems and concrete record syntax;
  5986 
  5987 
  5988 *** HOLCF ***
  5989 
  5990 * removed "axioms" and "generated by" sections;
  5991 
  5992 * replaced "ops" section by extended "consts" section, which is capable of
  5993   handling the continuous function space "->" directly;
  5994 
  5995 * domain package:
  5996   . proves theorems immediately and stores them in the theory,
  5997   . creates hierachical name space,
  5998   . now uses normal mixfix annotations (instead of cinfix...),
  5999   . minor changes to some names and values (for consistency),
  6000   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  6001   . separator between mutual domain defs: changed "," to "and",
  6002   . improved handling of sort constraints;  now they have to
  6003     appear on the left-hand side of the equations only;
  6004 
  6005 * fixed LAM <x,y,zs>.b syntax;
  6006 
  6007 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  6008 adm (%x. P (t x)), where P is chainfinite and t continuous;
  6009 
  6010 
  6011 *** FOL and ZF ***
  6012 
  6013 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6014   with `addloop' of the simplifier to faciliate case splitting in premises.
  6015 
  6016 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6017 in HOL, they strip ALL and --> from proved theorems;
  6018 
  6019 
  6020 
  6021 New in Isabelle94-8 (May 1997)
  6022 ------------------------------
  6023 
  6024 *** General Changes ***
  6025 
  6026 * new utilities to build / run / maintain Isabelle etc. (in parts
  6027 still somewhat experimental); old Makefiles etc. still functional;
  6028 
  6029 * new 'Isabelle System Manual';
  6030 
  6031 * INSTALL text, together with ./configure and ./build scripts;
  6032 
  6033 * reimplemented type inference for greater efficiency, better error
  6034 messages and clean internal interface;
  6035 
  6036 * prlim command for dealing with lots of subgoals (an easier way of
  6037 setting goals_limit);
  6038 
  6039 
  6040 *** Syntax ***
  6041 
  6042 * supports alternative (named) syntax tables (parser and pretty
  6043 printer); internal interface is provided by add_modesyntax(_i);
  6044 
  6045 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6046 be used in conjunction with the Isabelle symbol font; uses the
  6047 "symbols" syntax table;
  6048 
  6049 * added token_translation interface (may translate name tokens in
  6050 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6051 the current print_mode); IMPORTANT: user print translation functions
  6052 are responsible for marking newly introduced bounds
  6053 (Syntax.mark_boundT);
  6054 
  6055 * token translations for modes "xterm" and "xterm_color" that display
  6056 names in bold, underline etc. or colors (which requires a color
  6057 version of xterm);
  6058 
  6059 * infixes may now be declared with names independent of their syntax;
  6060 
  6061 * added typed_print_translation (like print_translation, but may
  6062 access type of constant);
  6063 
  6064 
  6065 *** Classical Reasoner ***
  6066 
  6067 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6068 some limitations.  Blast_tac...
  6069   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6070   + ignores elimination rules that don't have the correct format
  6071         (the conclusion MUST be a formula variable)
  6072   + ignores types, which can make HOL proofs fail
  6073   + rules must not require higher-order unification, e.g. apply_type in ZF
  6074     [message "Function Var's argument not a bound variable" relates to this]
  6075   + its proof strategy is more general but can actually be slower
  6076 
  6077 * substitution with equality assumptions no longer permutes other
  6078 assumptions;
  6079 
  6080 * minor changes in semantics of addafter (now called addaltern); renamed
  6081 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6082 (and access functions for it);
  6083 
  6084 * improved combination of classical reasoner and simplifier:
  6085   + functions for handling clasimpsets
  6086   + improvement of addss: now the simplifier is called _after_ the
  6087     safe steps.
  6088   + safe variant of addss called addSss: uses safe simplifications
  6089     _during_ the safe steps. It is more complete as it allows multiple
  6090     instantiations of unknowns (e.g. with slow_tac).
  6091 
  6092 *** Simplifier ***
  6093 
  6094 * added interface for simplification procedures (functions that
  6095 produce *proven* rewrite rules on the fly, depending on current
  6096 redex);
  6097 
  6098 * ordering on terms as parameter (used for ordered rewriting);
  6099 
  6100 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6101 
  6102 * the solver is now split into a safe and an unsafe part.
  6103 This should be invisible for the normal user, except that the
  6104 functions setsolver and addsolver have been renamed to setSolver and
  6105 addSolver; added safe_asm_full_simp_tac;
  6106 
  6107 
  6108 *** HOL ***
  6109 
  6110 * a generic induction tactic `induct_tac' which works for all datatypes and
  6111 also for type `nat';
  6112 
  6113 * a generic case distinction tactic `exhaust_tac' which works for all
  6114 datatypes and also for type `nat';
  6115 
  6116 * each datatype comes with a function `size';
  6117 
  6118 * patterns in case expressions allow tuple patterns as arguments to
  6119 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6120 
  6121 * primrec now also works with type nat;
  6122 
  6123 * recdef: a new declaration form, allows general recursive functions to be
  6124 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6125 
  6126 * the constant for negation has been renamed from "not" to "Not" to
  6127 harmonize with FOL, ZF, LK, etc.;
  6128 
  6129 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6130 infinite lists;
  6131 
  6132 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6133 
  6134 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6135 problems in commutative rings, using axiomatic type classes for + and *;
  6136 
  6137 * more examples in HOL/MiniML and HOL/Auth;
  6138 
  6139 * more default rewrite rules for quantifiers, union/intersection;
  6140 
  6141 * a new constant `arbitrary == @x.False';
  6142 
  6143 * HOLCF/IOA replaces old HOL/IOA;
  6144 
  6145 * HOLCF changes: derived all rules and arities
  6146   + axiomatic type classes instead of classes
  6147   + typedef instead of faking type definitions
  6148   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6149   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6150   + eliminated the types void, one, tr
  6151   + use unit lift and bool lift (with translations) instead of one and tr
  6152   + eliminated blift from Lift3.thy (use Def instead of blift)
  6153   all eliminated rules are derived as theorems --> no visible changes ;
  6154 
  6155 
  6156 *** ZF ***
  6157 
  6158 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6159 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6160 as ZF_cs addSIs [equalityI];
  6161 
  6162 
  6163 
  6164 New in Isabelle94-7 (November 96)
  6165 ---------------------------------
  6166 
  6167 * allowing negative levels (as offsets) in prlev and choplev;
  6168 
  6169 * super-linear speedup for large simplifications;
  6170 
  6171 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6172 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6173 FAIL); can suppress it using the command Delsimps (ex_simps @
  6174 all_simps); De Morgan laws are also now included, by default;
  6175 
  6176 * improved printing of ==>  :  ~:
  6177 
  6178 * new object-logic "Sequents" adds linear logic, while replacing LK
  6179 and Modal (thanks to Sara Kalvala);
  6180 
  6181 * HOL/Auth: correctness proofs for authentication protocols;
  6182 
  6183 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6184 examples on HOL/Auth);
  6185 
  6186 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6187 the rewriter and classical reasoner simultaneously;
  6188 
  6189 * function uresult no longer returns theorems in "standard" format;
  6190 regain previous version by: val uresult = standard o uresult;
  6191 
  6192 
  6193 
  6194 New in Isabelle94-6
  6195 -------------------
  6196 
  6197 * oracles -- these establish an interface between Isabelle and trusted
  6198 external reasoners, which may deliver results as theorems;
  6199 
  6200 * proof objects (in particular record all uses of oracles);
  6201 
  6202 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6203 
  6204 * "constdefs" section in theory files;
  6205 
  6206 * "primrec" section (HOL) no longer requires names;
  6207 
  6208 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6209 
  6210 
  6211 
  6212 New in Isabelle94-5
  6213 -------------------
  6214 
  6215 * reduced space requirements;
  6216 
  6217 * automatic HTML generation from theories;
  6218 
  6219 * theory files no longer require "..." (quotes) around most types;
  6220 
  6221 * new examples, including two proofs of the Church-Rosser theorem;
  6222 
  6223 * non-curried (1994) version of HOL is no longer distributed;
  6224 
  6225 
  6226 
  6227 New in Isabelle94-4
  6228 -------------------
  6229 
  6230 * greatly reduced space requirements;
  6231 
  6232 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6233 
  6234 * searchable theorem database (see the section "Retrieving theorems" on
  6235 page 8 of the Reference Manual);
  6236 
  6237 * new examples, including Grabczewski's monumental case study of the
  6238 Axiom of Choice;
  6239 
  6240 * The previous version of HOL renamed to Old_HOL;
  6241 
  6242 * The new version of HOL (previously called CHOL) uses a curried syntax
  6243 for functions.  Application looks like f a b instead of f(a,b);
  6244 
  6245 * Mutually recursive inductive definitions finally work in HOL;
  6246 
  6247 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6248 translates to the operator "split";
  6249 
  6250 
  6251 
  6252 New in Isabelle94-3
  6253 -------------------
  6254 
  6255 * new infix operator, addss, allowing the classical reasoner to
  6256 perform simplification at each step of its search.  Example:
  6257         fast_tac (cs addss ss)
  6258 
  6259 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6260 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6261 look like (a,b) instead of <a,b>;
  6262