NEWS
author wenzelm
Sat May 30 15:00:23 2009 +0200 (2009-05-30)
changeset 31304 00a9c674cf40
parent 31001 7e6ffd8f51a9
child 31306 a74ee84288a0
permissions -rw-r--r--
eliminated old Method.add_method(s);
     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 Method.add_methods and related cominators for "method
    32 args".  INCOMPATIBILITY, need to use simplified Method.setup
    33 introduced in Isabelle2009.
    34 
    35 
    36 
    37 New in Isabelle2009 (April 2009)
    38 --------------------------------
    39 
    40 *** General ***
    41 
    42 * Simplified main Isabelle executables, with less surprises on
    43 case-insensitive file-systems (such as Mac OS).
    44 
    45   - The main Isabelle tool wrapper is now called "isabelle" instead of
    46     "isatool."
    47 
    48   - The former "isabelle" alias for "isabelle-process" has been
    49     removed (should rarely occur to regular users).
    50 
    51   - The former "isabelle-interface" and its alias "Isabelle" have been
    52     removed (interfaces are now regular Isabelle tools).
    53 
    54 Within scripts and make files, the Isabelle environment variables
    55 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    56 respectively.  (The latter are still available as legacy feature.)
    57 
    58 The old isabelle-interface wrapper could react in confusing ways if
    59 the interface was uninstalled or changed otherwise.  Individual
    60 interface tool configuration is now more explicit, see also the
    61 Isabelle system manual.  In particular, Proof General is now available
    62 via "isabelle emacs".
    63 
    64 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    65 purge installed copies of Isabelle executables and re-run "isabelle
    66 install -p ...", or use symlinks.
    67 
    68 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    69 old ~/isabelle, which was slightly non-standard and apt to cause
    70 surprises on case-insensitive file-systems (such as Mac OS).
    71 
    72 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    73 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    74 care is required when using older releases of Isabelle.  Note that
    75 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    76 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
    77 
    78 * Proofs of fully specified statements are run in parallel on
    79 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
    80 a regular 4-core machine, if the initial heap space is made reasonably
    81 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
    82 
    83 * The main reference manuals ("isar-ref", "implementation", and
    84 "system") have been updated and extended.  Formally checked references
    85 as hyperlinks are now available uniformly.
    86 
    87 
    88 *** Pure ***
    89 
    90 * Complete re-implementation of locales.  INCOMPATIBILITY in several
    91 respects.  The most important changes are listed below.  See the
    92 Tutorial on Locales ("locales" manual) for details.
    93 
    94 - In locale expressions, instantiation replaces renaming.  Parameters
    95 must be declared in a for clause.  To aid compatibility with previous
    96 parameter inheritance, in locale declarations, parameters that are not
    97 'touched' (instantiation position "_" or omitted) are implicitly added
    98 with their syntax at the beginning of the for clause.
    99 
   100 - Syntax from abbreviations and definitions in locales is available in
   101 locale expressions and context elements.  The latter is particularly
   102 useful in locale declarations.
   103 
   104 - More flexible mechanisms to qualify names generated by locale
   105 expressions.  Qualifiers (prefixes) may be specified in locale
   106 expressions, and can be marked as mandatory (syntax: "name!:") or
   107 optional (syntax "name?:").  The default depends for plain "name:"
   108 depends on the situation where a locale expression is used: in
   109 commands 'locale' and 'sublocale' prefixes are optional, in
   110 'interpretation' and 'interpret' prefixes are mandatory.  The old
   111 implicit qualifiers derived from the parameter names of a locale are
   112 no longer generated.
   113 
   114 - Command "sublocale l < e" replaces "interpretation l < e".  The
   115 instantiation clause in "interpretation" and "interpret" (square
   116 brackets) is no longer available.  Use locale expressions.
   117 
   118 - When converting proof scripts, mandatory qualifiers in
   119 'interpretation' and 'interpret' should be retained by default, even
   120 if this is an INCOMPATIBILITY compared to former behavior.  In the
   121 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   122 in locale expressions range over a single locale instance only.
   123 
   124 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   125 In existing theorem specifications replace the includes element by the
   126 respective context elements of the included locale, omitting those
   127 that are already present in the theorem specification.  Multiple
   128 assume elements of a locale should be replaced by a single one
   129 involving the locale predicate.  In the proof body, declarations (most
   130 notably theorems) may be regained by interpreting the respective
   131 locales in the proof context as required (command "interpret").
   132 
   133 If using "includes" in replacement of a target solely because the
   134 parameter types in the theorem are not as general as in the target,
   135 consider declaring a new locale with additional type constraints on
   136 the parameters (context element "constrains").
   137 
   138 - Discontinued "locale (open)".  INCOMPATIBILITY.
   139 
   140 - Locale interpretation commands no longer attempt to simplify goal.
   141 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   142 methods intro_locales and unfold_locales to clarify.
   143 
   144 - Locale interpretation commands no longer accept interpretation
   145 attributes.  INCOMPATIBILITY.
   146 
   147 * Class declaration: so-called "base sort" must not be given in import
   148 list any longer, but is inferred from the specification.  Particularly
   149 in HOL, write
   150 
   151     class foo = ...
   152 
   153 instead of
   154 
   155     class foo = type + ...
   156 
   157 * Class target: global versions of theorems stemming do not carry a
   158 parameter prefix any longer.  INCOMPATIBILITY.
   159 
   160 * Class 'instance' command no longer accepts attached definitions.
   161 INCOMPATIBILITY, use proper 'instantiation' target instead.
   162 
   163 * Recovered hiding of consts, which was accidentally broken in
   164 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   165 makes c inaccessible; consider using ``hide (open) const c'' instead.
   166 
   167 * Slightly more coherent Pure syntax, with updated documentation in
   168 isar-ref manual.  Removed locales meta_term_syntax and
   169 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   170 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   171 directly in regular applications.
   172 
   173 * There is a new syntactic category "float_const" for signed decimal
   174 fractions (e.g. 123.45 or -123.45).
   175 
   176 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   177 interface with 'setup' command instead.
   178 
   179 * Command 'local_setup' is similar to 'setup', but operates on a local
   180 theory context.
   181 
   182 * The 'axiomatization' command now only works within a global theory
   183 context.  INCOMPATIBILITY.
   184 
   185 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   186 hypotheses.  Sorts required in the course of reasoning need to be
   187 covered by the constraints in the initial statement, completed by the
   188 type instance information of the background theory.  Non-trivial sort
   189 hypotheses, which rarely occur in practice, may be specified via
   190 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   191 
   192   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   193 
   194 The result contains an implicit sort hypotheses as before --
   195 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   196 normalization.
   197 
   198 * Generalized Isar history, with support for linear undo, direct state
   199 addressing etc.
   200 
   201 * Changed defaults for unify configuration options:
   202 
   203   unify_trace_bound = 50 (formerly 25)
   204   unify_search_bound = 60 (formerly 30)
   205 
   206 * Different bookkeeping for code equations (INCOMPATIBILITY):
   207 
   208   a) On theory merge, the last set of code equations for a particular
   209      constant is taken (in accordance with the policy applied by other
   210      parts of the code generator framework).
   211 
   212   b) Code equations stemming from explicit declarations (e.g. code
   213      attribute) gain priority over default code equations stemming
   214      from definition, primrec, fun etc.
   215 
   216 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   217 
   218 * Unified theorem tables for both code generators.  Thus [code
   219 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   220 
   221 * Command 'find_consts' searches for constants based on type and name
   222 patterns, e.g.
   223 
   224     find_consts "_ => bool"
   225 
   226 By default, matching is against subtypes, but it may be restricted to
   227 the whole type.  Searching by name is possible.  Multiple queries are
   228 conjunctive and queries may be negated by prefixing them with a
   229 hyphen:
   230 
   231     find_consts strict: "_ => bool" name: "Int" -"int => int"
   232 
   233 * New 'find_theorems' criterion "solves" matches theorems that
   234 directly solve the current goal (modulo higher-order unification).
   235 
   236 * Auto solve feature for main theorem statements: whenever a new goal
   237 is stated, "find_theorems solves" is called; any theorems that could
   238 solve the lemma directly are listed as part of the goal state.
   239 Cf. associated options in Proof General Isabelle settings menu,
   240 enabled by default, with reasonable timeout for pathological cases of
   241 higher-order unification.
   242 
   243 
   244 *** Document preparation ***
   245 
   246 * Antiquotation @{lemma} now imitates a regular terminal proof,
   247 demanding keyword 'by' and supporting the full method expression
   248 syntax just like the Isar command 'by'.
   249 
   250 
   251 *** HOL ***
   252 
   253 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   254 points Main and Complex_Main remain as before.
   255 
   256 * Logic image HOL-Plain provides a minimal HOL with the most important
   257 tools available (inductive, datatype, primrec, ...).  This facilitates
   258 experimentation and tool development.  Note that user applications
   259 (and library theories) should never refer to anything below theory
   260 Main, as before.
   261 
   262 * Logic image HOL-Main stops at theory Main, and thus facilitates
   263 experimentation due to shorter build times.
   264 
   265 * Logic image HOL-NSA contains theories of nonstandard analysis which
   266 were previously part of former HOL-Complex.  Entry point Hyperreal
   267 remains valid, but theories formerly using Complex_Main should now use
   268 new entry point Hypercomplex.
   269 
   270 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   271 Posix processes.  Avoids potentially expensive forking of the ML
   272 process.  New thread-based implementation also works on non-Unix
   273 platforms (Cygwin).  Provers are no longer hardwired, but defined
   274 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   275 commands are covered in the isar-ref manual.
   276 
   277 * Wrapper scripts for remote SystemOnTPTP service allows to use
   278 sledgehammer without local ATP installation (Vampire etc.). Other
   279 provers may be included via suitable ML wrappers, see also
   280 src/HOL/ATP_Linkup.thy.
   281 
   282 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   283 menu.
   284 
   285 * The metis method no longer fails because the theorem is too trivial
   286 (contains the empty clause).
   287 
   288 * The metis method now fails in the usual manner, rather than raising
   289 an exception, if it determines that it cannot prove the theorem.
   290 
   291 * Method "coherent" implements a prover for coherent logic (see also
   292 src/Tools/coherent.ML).
   293 
   294 * Constants "undefined" and "default" replace "arbitrary".  Usually
   295 "undefined" is the right choice to replace "arbitrary", though
   296 logically there is no difference.  INCOMPATIBILITY.
   297 
   298 * Command "value" now integrates different evaluation mechanisms.  The
   299 result of the first successful evaluation mechanism is printed.  In
   300 square brackets a particular named evaluation mechanisms may be
   301 specified (currently, [SML], [code] or [nbe]).  See further
   302 src/HOL/ex/Eval_Examples.thy.
   303 
   304 * Normalization by evaluation now allows non-leftlinear equations.
   305 Declare with attribute [code nbe].
   306 
   307 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   308 as the structured Isar versions "cases" and "induct", cf. the
   309 corresponding "cases" and "induct" attributes.  Mutual induction rules
   310 are now presented as a list of individual projections
   311 (e.g. foo_bar.inducts for types foo and bar); the old format with
   312 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   313 rare situations a different rule is selected --- notably nested tuple
   314 elimination instead of former prod.exhaust: use explicit (case_tac t
   315 rule: prod.exhaust) here.
   316 
   317 * Attributes "cases", "induct", "coinduct" support "del" option.
   318 
   319 * Removed fact "case_split_thm", which duplicates "case_split".
   320 
   321 * The option datatype has been moved to a new theory Option.  Renamed
   322 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   323 
   324 * New predicate "strict_mono" classifies strict functions on partial
   325 orders.  With strict functions on linear orders, reasoning about
   326 (in)equalities is facilitated by theorems "strict_mono_eq",
   327 "strict_mono_less_eq" and "strict_mono_less".
   328 
   329 * Some set operations are now proper qualified constants with
   330 authentic syntax.  INCOMPATIBILITY:
   331 
   332     op Int ~>   Set.Int
   333     op Un ~>    Set.Un
   334     INTER ~>    Set.INTER
   335     UNION ~>    Set.UNION
   336     Inter ~>    Set.Inter
   337     Union ~>    Set.Union
   338     {} ~>       Set.empty
   339     UNIV ~>     Set.UNIV
   340 
   341 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   342 theory Set.
   343 
   344 * Auxiliary class "itself" has disappeared -- classes without any
   345 parameter are treated as expected by the 'class' command.
   346 
   347 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   348 
   349 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   350 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   351 
   352 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   353 method "approximation".  It proves formulas on real values by using
   354 interval arithmetic.  In the formulas are also the transcendental
   355 functions sin, cos, tan, atan, ln, exp and the constant pi are
   356 allowed. For examples see
   357 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   358 
   359 * Theory "Reflection" now resides in HOL/Library.
   360 
   361 * Entry point to Word library now simply named "Word".
   362 INCOMPATIBILITY.
   363 
   364 * Made source layout more coherent with logical distribution
   365 structure:
   366 
   367     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   368     src/HOL/Library/Code_Message.thy ~> src/HOL/
   369     src/HOL/Library/GCD.thy ~> src/HOL/
   370     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   371     src/HOL/Library/Parity.thy ~> src/HOL/
   372     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   373     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   374     src/HOL/Real/Lubs.thy ~> src/HOL/
   375     src/HOL/Real/PReal.thy ~> src/HOL/
   376     src/HOL/Real/Rational.thy ~> src/HOL/
   377     src/HOL/Real/RComplete.thy ~> src/HOL/
   378     src/HOL/Real/RealDef.thy ~> src/HOL/
   379     src/HOL/Real/RealPow.thy ~> src/HOL/
   380     src/HOL/Real/Real.thy ~> src/HOL/
   381     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   382     src/HOL/Complex/Complex.thy ~> src/HOL/
   383     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   384     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   385     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   386     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   387     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   388     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   389     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   390     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   391     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   392     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   393     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   394     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   395     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   396     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   397     src/HOL/Real/Float ~> src/HOL/Library/
   398     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   399     src/HOL/Real/RealVector.thy ~> src/HOL/
   400 
   401     src/HOL/arith_data.ML ~> src/HOL/Tools
   402     src/HOL/hologic.ML ~> src/HOL/Tools
   403     src/HOL/simpdata.ML ~> src/HOL/Tools
   404     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   405     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   406     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   407     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   408     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   409     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   410     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   411 
   412     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   413     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   414     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   415     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   416     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   417     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   418 
   419 * If methods "eval" and "evaluation" encounter a structured proof
   420 state with !!/==>, only the conclusion is evaluated to True (if
   421 possible), avoiding strange error messages.
   422 
   423 * Method "sizechange" automates termination proofs using (a
   424 modification of) the size-change principle.  Requires SAT solver.  See
   425 src/HOL/ex/Termination.thy for examples.
   426 
   427 * Simplifier: simproc for let expressions now unfolds if bound
   428 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   429 
   430 * Method "arith": Linear arithmetic now ignores all inequalities when
   431 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   432 
   433 * New attribute "arith" for facts that should always be used
   434 automatically by arithmetic. It is intended to be used locally in
   435 proofs, e.g.
   436 
   437   assumes [arith]: "x > 0"
   438 
   439 Global usage is discouraged because of possible performance impact.
   440 
   441 * New classes "top" and "bot" with corresponding operations "top" and
   442 "bot" in theory Orderings; instantiation of class "complete_lattice"
   443 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   444 
   445 * Changed definition lemma "less_fun_def" in order to provide an
   446 instance for preorders on functions; use lemma "less_le" instead.
   447 INCOMPATIBILITY.
   448 
   449 * Theory Orderings: class "wellorder" moved here, with explicit
   450 induction rule "less_induct" as assumption.  For instantiation of
   451 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   452 INCOMPATIBILITY.
   453 
   454 * Theory Orderings: added class "preorder" as superclass of "order".
   455 INCOMPATIBILITY: Instantiation proofs for order, linorder
   456 etc. slightly changed.  Some theorems named order_class.* now named
   457 preorder_class.*.
   458 
   459 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   460 "diag" to "Id_on".
   461 
   462 * Theory Finite_Set: added a new fold combinator of type
   463 
   464   ('a => 'b => 'b) => 'b => 'a set => 'b
   465 
   466 Occasionally this is more convenient than the old fold combinator
   467 which is now defined in terms of the new one and renamed to
   468 fold_image.
   469 
   470 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   471 and "ring_simps" have been replaced by "algebra_simps" (which can be
   472 extended with further lemmas!).  At the moment both still exist but
   473 the former will disappear at some point.
   474 
   475 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   476 class recpower.  Type-specific simp rules for various recpower types
   477 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   478 
   479 rat_power_0    -> power_0
   480 rat_power_Suc  -> power_Suc
   481 realpow_0      -> power_0
   482 realpow_Suc    -> power_Suc
   483 complexpow_0   -> power_0
   484 complexpow_Suc -> power_Suc
   485 power_poly_0   -> power_0
   486 power_poly_Suc -> power_Suc
   487 
   488 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   489 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   490 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   491 of lemmas from Divides has been generalized from nat to class
   492 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   493 renames resulting from duplicate elimination:
   494 
   495     dvd_def_mod ~>          dvd_eq_mod_eq_0
   496     zero_dvd_iff ~>         dvd_0_left_iff
   497     dvd_0 ~>                dvd_0_right
   498     DIVISION_BY_ZERO_DIV ~> div_by_0
   499     DIVISION_BY_ZERO_MOD ~> mod_by_0
   500     mult_div ~>             div_mult_self2_is_id
   501     mult_mod ~>             mod_mult_self2_is_0
   502 
   503 * Theory IntDiv: removed many lemmas that are instances of class-based
   504 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   505 rename old lemmas as follows:
   506 
   507 dvd_diff               -> nat_dvd_diff
   508 dvd_zminus_iff         -> dvd_minus_iff
   509 mod_add1_eq            -> mod_add_eq
   510 mod_mult1_eq           -> mod_mult_right_eq
   511 mod_mult1_eq'          -> mod_mult_left_eq
   512 mod_mult_distrib_mod   -> mod_mult_eq
   513 nat_mod_add_left_eq    -> mod_add_left_eq
   514 nat_mod_add_right_eq   -> mod_add_right_eq
   515 nat_mod_div_trivial    -> mod_div_trivial
   516 nat_mod_mod_trivial    -> mod_mod_trivial
   517 zdiv_zadd_self1        -> div_add_self1
   518 zdiv_zadd_self2        -> div_add_self2
   519 zdiv_zmult_self1       -> div_mult_self2_is_id
   520 zdiv_zmult_self2       -> div_mult_self1_is_id
   521 zdvd_triv_left         -> dvd_triv_left
   522 zdvd_triv_right        -> dvd_triv_right
   523 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   524 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   525 zmod_zadd_left_eq      -> mod_add_left_eq
   526 zmod_zadd_right_eq     -> mod_add_right_eq
   527 zmod_zadd_self1        -> mod_add_self1
   528 zmod_zadd_self2        -> mod_add_self2
   529 zmod_zadd1_eq          -> mod_add_eq
   530 zmod_zdiff1_eq         -> mod_diff_eq
   531 zmod_zdvd_zmod         -> mod_mod_cancel
   532 zmod_zmod_cancel       -> mod_mod_cancel
   533 zmod_zmult_self1       -> mod_mult_self2_is_0
   534 zmod_zmult_self2       -> mod_mult_self1_is_0
   535 zmod_1                 -> mod_by_1
   536 zdiv_1                 -> div_by_1
   537 zdvd_abs1              -> abs_dvd_iff
   538 zdvd_abs2              -> dvd_abs_iff
   539 zdvd_refl              -> dvd_refl
   540 zdvd_trans             -> dvd_trans
   541 zdvd_zadd              -> dvd_add
   542 zdvd_zdiff             -> dvd_diff
   543 zdvd_zminus_iff        -> dvd_minus_iff
   544 zdvd_zminus2_iff       -> minus_dvd_iff
   545 zdvd_zmultD            -> dvd_mult_right
   546 zdvd_zmultD2           -> dvd_mult_left
   547 zdvd_zmult_mono        -> mult_dvd_mono
   548 zdvd_0_right           -> dvd_0_right
   549 zdvd_0_left            -> dvd_0_left_iff
   550 zdvd_1_left            -> one_dvd
   551 zminus_dvd_iff         -> minus_dvd_iff
   552 
   553 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   554 
   555 * The real numbers offer decimal input syntax: 12.34 is translated
   556 into 1234/10^2. This translation is not reversed upon output.
   557 
   558 * Theory Library/Polynomial defines an abstract type 'a poly of
   559 univariate polynomials with coefficients of type 'a.  In addition to
   560 the standard ring operations, it also supports div and mod.  Code
   561 generation is also supported, using list-style constructors.
   562 
   563 * Theory Library/Inner_Product defines a class of real_inner for real
   564 inner product spaces, with an overloaded operation inner :: 'a => 'a
   565 => real.  Class real_inner is a subclass of real_normed_vector from
   566 theory RealVector.
   567 
   568 * Theory Library/Product_Vector provides instances for the product
   569 type 'a * 'b of several classes from RealVector and Inner_Product.
   570 Definitions of addition, subtraction, scalar multiplication, norms,
   571 and inner products are included.
   572 
   573 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   574 addition to the field operations, numerals and case syntax are also
   575 supported.
   576 
   577 * Theory Library/Diagonalize provides constructive version of Cantor's
   578 first diagonalization argument.
   579 
   580 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   581 zlcm (for int); carried together from various gcd/lcm developements in
   582 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   583 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   584 may recover tupled syntax as follows:
   585 
   586     hide (open) const gcd
   587     abbreviation gcd where
   588       "gcd == (%(a, b). GCD.gcd a b)"
   589     notation (output)
   590       GCD.gcd ("gcd '(_, _')")
   591 
   592 The same works for lcm, zgcd, zlcm.
   593 
   594 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   595 instantiations for algebraic structures.  Removed some duplicate
   596 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   597 
   598 * ML antiquotation @{code} takes a constant as argument and generates
   599 corresponding code in background and inserts name of the corresponding
   600 resulting ML value/function/datatype constructor binding in place.
   601 All occurrences of @{code} with a single ML block are generated
   602 simultaneously.  Provides a generic and safe interface for
   603 instrumentalizing code generation.  See
   604 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   605 In future you ought to refrain from ad-hoc compiling generated SML
   606 code on the ML toplevel.  Note that (for technical reasons) @{code}
   607 cannot refer to constants for which user-defined serializations are
   608 set.  Refer to the corresponding ML counterpart directly in that
   609 cases.
   610 
   611 * Command 'rep_datatype': instead of theorem names the command now
   612 takes a list of terms denoting the constructors of the type to be
   613 represented as datatype.  The characteristic theorems have to be
   614 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   615 have disappeared in favour of existing ones:
   616 
   617     unit_induct                 ~> unit.induct
   618     prod_induct                 ~> prod.induct
   619     sum_induct                  ~> sum.induct
   620     Suc_Suc_eq                  ~> nat.inject
   621     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   622 
   623 
   624 *** HOL-Algebra ***
   625 
   626 * New locales for orders and lattices where the equivalence relation
   627 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   628 locales use a record structure with field eq for the equivalence.
   629 
   630 * New theory of factorial domains.
   631 
   632 * Units_l_inv and Units_r_inv are now simp rules by default.
   633 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   634 and/or r_inv will now also require deletion of these lemmas.
   635 
   636 * Renamed the following theorems, INCOMPATIBILITY:
   637 
   638 UpperD ~> Upper_memD
   639 LowerD ~> Lower_memD
   640 least_carrier ~> least_closed
   641 greatest_carrier ~> greatest_closed
   642 greatest_Lower_above ~> greatest_Lower_below
   643 one_zero ~> carrier_one_zero
   644 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   645 
   646 
   647 *** HOL-Nominal ***
   648 
   649 * Nominal datatypes can now contain type-variables.
   650 
   651 * Commands 'nominal_inductive' and 'equivariance' work with local
   652 theory targets.
   653 
   654 * Nominal primrec can now works with local theory targets and its
   655 specification syntax now conforms to the general format as seen in
   656 'inductive' etc.
   657 
   658 * Method "perm_simp" honours the standard simplifier attributes
   659 (no_asm), (no_asm_use) etc.
   660 
   661 * The new predicate #* is defined like freshness, except that on the
   662 left hand side can be a set or list of atoms.
   663 
   664 * Experimental command 'nominal_inductive2' derives strong induction
   665 principles for inductive definitions.  In contrast to
   666 'nominal_inductive', which can only deal with a fixed number of
   667 binders, it can deal with arbitrary expressions standing for sets of
   668 atoms to be avoided.  The only inductive definition we have at the
   669 moment that needs this generalisation is the typing rule for Lets in
   670 the algorithm W:
   671 
   672  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   673  -----------------------------------------------------------------
   674          Gamma |- Let x be t1 in t2 : T2
   675 
   676 In this rule one wants to avoid all the binders that are introduced by
   677 "close Gamma T1".  We are looking for other examples where this
   678 feature might be useful.  Please let us know.
   679 
   680 
   681 *** HOLCF ***
   682 
   683 * Reimplemented the simplification procedure for proving continuity
   684 subgoals.  The new simproc is extensible; users can declare additional
   685 continuity introduction rules with the attribute [cont2cont].
   686 
   687 * The continuity simproc now uses a different introduction rule for
   688 solving continuity subgoals on terms with lambda abstractions.  In
   689 some rare cases the new simproc may fail to solve subgoals that the
   690 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   691 Potential INCOMPATIBILITY.
   692 
   693 * Command 'fixrec': specification syntax now conforms to the general
   694 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   695 examples.  INCOMPATIBILITY.
   696 
   697 
   698 *** ZF ***
   699 
   700 * Proof of Zorn's Lemma for partial orders.
   701 
   702 
   703 *** ML ***
   704 
   705 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   706 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   707 depends on multithreading, so timouts will not work before Poly/ML
   708 5.2.1!
   709 
   710 * High-level support for concurrent ML programming, see
   711 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   712 particularly convenient to organize independent functional
   713 computations.  The concept of "synchronized variables" provides a
   714 higher-order interface for components with shared state, avoiding the
   715 delicate details of mutexes and condition variables.  (Requires
   716 Poly/ML 5.2.1 or later.)
   717 
   718 * ML bindings produced via Isar commands are stored within the Isar
   719 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   720 become thread-safe and work with undo as expected (concerning
   721 top-level bindings, not side-effects on global references).
   722 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   723 compiler at runtime; really global bindings need to be given outside a
   724 theory.  (Requires Poly/ML 5.2 or later.)
   725 
   726 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   727 context.  Top-level ML bindings are stored within the proof context in
   728 a purely sequential fashion, disregarding the nested proof structure.
   729 ML bindings introduced by 'ML_prf' are discarded at the end of the
   730 proof.  (Requires Poly/ML 5.2 or later.)
   731 
   732 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   733 and Method.setup, as well as Isar commands 'attribute_setup' and
   734 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   735 existing code accordingly, or use plain 'setup' together with old
   736 Method.add_method.
   737 
   738 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   739 to 'a -> thm, while results are always tagged with an authentic oracle
   740 name.  The Isar command 'oracle' is now polymorphic, no argument type
   741 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   742 accordingly.  Note that extra performance may be gained by producing
   743 the cterm carefully, avoiding slow Thm.cterm_of.
   744 
   745 * Simplified interface for defining document antiquotations via
   746 ThyOutput.antiquotation, ThyOutput.output, and optionally
   747 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   748 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   749 examples.
   750 
   751 * More systematic treatment of long names, abstract name bindings, and
   752 name space operations.  Basic operations on qualified names have been
   753 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   754 Long_Name.append.  Old type bstring has been mostly replaced by
   755 abstract type binding (see structure Binding), which supports precise
   756 qualification by packages and local theory targets, as well as proper
   757 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   758 bstring values into Binding.name, or better pass through abstract
   759 bindings everywhere.  See further src/Pure/General/long_name.ML,
   760 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   761 
   762 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   763 LocalTheory.note etc.) now refer to the *full* internal name, not the
   764 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   765 
   766 * Disposed old type and term read functions (Sign.read_def_typ,
   767 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   768 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   769 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   770 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   771 resort for legacy applications.
   772 
   773 * Disposed old declarations, tactics, tactic combinators that refer to
   774 the simpset or claset of an implicit theory (such as Addsimps,
   775 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   776 embedded ML text, or local_simpset_of with a proper context passed as
   777 explicit runtime argument.
   778 
   779 * Rules and tactics that read instantiations (read_instantiate,
   780 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   781 context, which is required for parsing and type-checking.  Moreover,
   782 the variables are specified as plain indexnames, not string encodings
   783 thereof.  INCOMPATIBILITY.
   784 
   785 * Generic Toplevel.add_hook interface allows to analyze the result of
   786 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   787 for theorem dependency output of transactions resulting in a new
   788 theory state.
   789 
   790 * ML antiquotations: block-structured compilation context indicated by
   791 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   792 
   793   @{binding name}                         - basic name binding
   794   @{let ?pat = term}                      - term abbreviation (HO matching)
   795   @{note name = fact}                     - fact abbreviation
   796   @{thm fact}                             - singleton fact (with attributes)
   797   @{thms fact}                            - general fact (with attributes)
   798   @{lemma prop by method}                 - singleton goal
   799   @{lemma prop by meth1 meth2}            - singleton goal
   800   @{lemma prop1 ... propN by method}      - general goal
   801   @{lemma prop1 ... propN by meth1 meth2} - general goal
   802   @{lemma (open) ...}                     - open derivation
   803 
   804 
   805 *** System ***
   806 
   807 * The Isabelle "emacs" tool provides a specific interface to invoke
   808 Proof General / Emacs, with more explicit failure if that is not
   809 installed (the old isabelle-interface script silently falls back on
   810 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   811 installation location of the Proof General distribution.
   812 
   813 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   814 the Isabelle process into a JVM/Scala application.  See
   815 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   816 process wrapper has been discontinued.)
   817 
   818 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   819 
   820 * Various status messages (with exact source position information) are
   821 emitted, if proper markup print mode is enabled.  This allows
   822 user-interface components to provide detailed feedback on internal
   823 prover operations.
   824 
   825 
   826 
   827 New in Isabelle2008 (June 2008)
   828 -------------------------------
   829 
   830 *** General ***
   831 
   832 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   833 and updated, with formally checked references as hyperlinks.
   834 
   835 * Theory loader: use_thy (and similar operations) no longer set the
   836 implicit ML context, which was occasionally hard to predict and in
   837 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   838 provides a proper context already.
   839 
   840 * Theory loader: old-style ML proof scripts being *attached* to a thy
   841 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   842 'use' within a theory file will do the job.
   843 
   844 * Name space merge now observes canonical order, i.e. the second space
   845 is inserted into the first one, while existing entries in the first
   846 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   847 swap theory imports.
   848 
   849 * Syntax: symbol \<chi> is now considered a letter.  Potential
   850 INCOMPATIBILITY in identifier syntax etc.
   851 
   852 * Outer syntax: string tokens no longer admit escaped white space,
   853 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   854 white space without escapes.
   855 
   856 * Outer syntax: string tokens may contain arbitrary character codes
   857 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   858 "foo_bar".
   859 
   860 
   861 *** Pure ***
   862 
   863 * Context-dependent token translations.  Default setup reverts locally
   864 fixed variables, and adds hilite markup for undeclared frees.
   865 
   866 * Unused theorems can be found using the new command 'unused_thms'.
   867 There are three ways of invoking it:
   868 
   869 (1) unused_thms
   870      Only finds unused theorems in the current theory.
   871 
   872 (2) unused_thms thy_1 ... thy_n -
   873      Finds unused theorems in the current theory and all of its ancestors,
   874      excluding the theories thy_1 ... thy_n and all of their ancestors.
   875 
   876 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   877      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   878      their ancestors, excluding the theories thy_1 ... thy_n and all of
   879      their ancestors.
   880 
   881 In order to increase the readability of the list produced by
   882 unused_thms, theorems that have been created by a particular instance
   883 of a theory command such as 'inductive' or 'function' are considered
   884 to belong to the same "group", meaning that if at least one theorem in
   885 this group is used, the other theorems in the same group are no longer
   886 reported as unused.  Moreover, if all theorems in the group are
   887 unused, only one theorem in the group is displayed.
   888 
   889 Note that proof objects have to be switched on in order for
   890 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   891 usually the case when using Proof General with the default settings).
   892 
   893 * Authentic naming of facts disallows ad-hoc overwriting of previous
   894 theorems within the same name space.  INCOMPATIBILITY, need to remove
   895 duplicate fact bindings, or even accidental fact duplications.  Note
   896 that tools may maintain dynamically scoped facts systematically, using
   897 PureThy.add_thms_dynamic.
   898 
   899 * Command 'hide' now allows to hide from "fact" name space as well.
   900 
   901 * Eliminated destructive theorem database, simpset, claset, and
   902 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   903 update of theories within ML code.
   904 
   905 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   906 INCOMPATIBILITY, object-logics depending on former Pure require
   907 additional setup PureThy.old_appl_syntax_setup; object-logics
   908 depending on former CPure need to refer to Pure.
   909 
   910 * Commands 'use' and 'ML' are now purely functional, operating on
   911 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   912 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   913 INCOMPATIBILITY.
   914 
   915 * Command 'setup': discontinued implicit version with ML reference.
   916 
   917 * Instantiation target allows for simultaneous specification of class
   918 instance operations together with an instantiation proof.
   919 Type-checking phase allows to refer to class operations uniformly.
   920 See src/HOL/Complex/Complex.thy for an Isar example and
   921 src/HOL/Library/Eval.thy for an ML example.
   922 
   923 * Indexing of literal facts: be more serious about including only
   924 facts from the visible specification/proof context, but not the
   925 background context (locale etc.).  Affects `prop` notation and method
   926 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   927 situations.
   928 
   929 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   930 "(open)" option, which used to expose internal bound variables to the
   931 proof text.
   932 
   933 * Isar statements: removed obsolete case "rule_context".
   934 INCOMPATIBILITY, better use explicit fixes/assumes.
   935 
   936 * Locale proofs: default proof step now includes 'unfold_locales';
   937 hence 'proof' without argument may be used to unfold locale
   938 predicates.
   939 
   940 
   941 *** Document preparation ***
   942 
   943 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   944 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   945 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   946 spot); renamed link color from "darkblue" to "linkcolor" (default
   947 value unchanged, can be redefined via \definecolor); no longer sets
   948 "a4paper" option (unnecessary or even intrusive).
   949 
   950 * Antiquotation @{lemma A method} proves proposition A by the given
   951 method (either a method name or a method name plus (optional) method
   952 arguments in parentheses) and prints A just like @{prop A}.
   953 
   954 
   955 *** HOL ***
   956 
   957 * New primrec package.  Specification syntax conforms in style to
   958 definition/function/....  No separate induction rule is provided.  The
   959 "primrec" command distinguishes old-style and new-style specifications
   960 by syntax.  The former primrec package is now named OldPrimrecPackage.
   961 When adjusting theories, beware: constants stemming from new-style
   962 primrec specifications have authentic syntax.
   963 
   964 * Metis prover is now an order of magnitude faster, and also works
   965 with multithreading.
   966 
   967 * Metis: the maximum number of clauses that can be produced from a
   968 theorem is now given by the attribute max_clauses.  Theorems that
   969 exceed this number are ignored, with a warning printed.
   970 
   971 * Sledgehammer no longer produces structured proofs by default. To
   972 enable, declare [[sledgehammer_full = true]].  Attributes
   973 reconstruction_modulus, reconstruction_sorts renamed
   974 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   975 
   976 * Method "induct_scheme" derives user-specified induction rules
   977 from well-founded induction and completeness of patterns. This factors
   978 out some operations that are done internally by the function package
   979 and makes them available separately.  See
   980 src/HOL/ex/Induction_Scheme.thy for examples.
   981 
   982 * More flexible generation of measure functions for termination
   983 proofs: Measure functions can be declared by proving a rule of the
   984 form "is_measure f" and giving it the [measure_function] attribute.
   985 The "is_measure" predicate is logically meaningless (always true), and
   986 just guides the heuristic.  To find suitable measure functions, the
   987 termination prover sets up the goal "is_measure ?f" of the appropriate
   988 type and generates all solutions by prolog-style backwards proof using
   989 the declared rules.
   990 
   991 This setup also deals with rules like 
   992 
   993   "is_measure f ==> is_measure (list_size f)"
   994 
   995 which accommodates nested datatypes that recurse through lists.
   996 Similar rules are predeclared for products and option types.
   997 
   998 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   999 
  1000   INCOMPATIBILITIES:
  1001 
  1002   - Definitions of overloaded constants on sets have to be replaced by
  1003     definitions on => and bool.
  1004 
  1005   - Some definitions of overloaded operators on sets can now be proved
  1006     using the definitions of the operators on => and bool.  Therefore,
  1007     the following theorems have been renamed:
  1008 
  1009       subset_def   -> subset_eq
  1010       psubset_def  -> psubset_eq
  1011       set_diff_def -> set_diff_eq
  1012       Compl_def    -> Compl_eq
  1013       Sup_set_def  -> Sup_set_eq
  1014       Inf_set_def  -> Inf_set_eq
  1015       sup_set_def  -> sup_set_eq
  1016       inf_set_def  -> inf_set_eq
  1017 
  1018   - Due to the incompleteness of the HO unification algorithm, some
  1019     rules such as subst may require manual instantiation, if some of
  1020     the unknowns in the rule is a set.
  1021 
  1022   - Higher order unification and forward proofs:
  1023     The proof pattern
  1024 
  1025       have "P (S::'a set)" <...>
  1026       then have "EX S. P S" ..
  1027 
  1028     no longer works (due to the incompleteness of the HO unification
  1029     algorithm) and must be replaced by the pattern
  1030 
  1031       have "EX S. P S"
  1032       proof
  1033         show "P S" <...>
  1034       qed
  1035 
  1036   - Calculational reasoning with subst (or similar rules):
  1037     The proof pattern
  1038 
  1039       have "P (S::'a set)" <...>
  1040       also have "S = T" <...>
  1041       finally have "P T" .
  1042 
  1043     no longer works (for similar reasons as the previous example) and
  1044     must be replaced by something like
  1045 
  1046       have "P (S::'a set)" <...>
  1047       moreover have "S = T" <...>
  1048       ultimately have "P T" by simp
  1049 
  1050   - Tactics or packages written in ML code:
  1051     Code performing pattern matching on types via
  1052 
  1053       Type ("set", [T]) => ...
  1054 
  1055     must be rewritten. Moreover, functions like strip_type or
  1056     binder_types no longer return the right value when applied to a
  1057     type of the form
  1058 
  1059       T1 => ... => Tn => U => bool
  1060 
  1061     rather than
  1062 
  1063       T1 => ... => Tn => U set
  1064 
  1065 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1066 Wellfounded_Relations to theory Wellfounded.
  1067 
  1068 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1069 
  1070 * Class finite no longer treats UNIV as class parameter.  Use class
  1071 enum from theory Library/Enum instead to achieve a similar effect.
  1072 INCOMPATIBILITY.
  1073 
  1074 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1075 and "Cons".  INCOMPATIBILITY.
  1076 
  1077 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1078 Potential INCOMPATIBILITY.
  1079 
  1080 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1081 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1082 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1083 
  1084 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1085 the same name in theory Orderings:
  1086 
  1087   less_trans
  1088   less_linear
  1089   le_imp_less_or_eq
  1090   le_less_trans
  1091   less_le_trans
  1092   less_not_sym
  1093   less_asym
  1094 
  1095 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1096 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1097 and different variable names.
  1098 
  1099 * Library/Option_ord.thy: Canonical order on option type.
  1100 
  1101 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1102 finite maps.
  1103 
  1104 * Library/Countable.thy: Type class for countable types.
  1105 
  1106 * Theory Int: The representation of numerals has changed.  The infix
  1107 operator BIT and the bit datatype with constructors B0 and B1 have
  1108 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1109 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1110 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1111 accordingly.
  1112 
  1113 * Theory Nat: definition of <= and < on natural numbers no longer
  1114 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1115 le_def and less_def have disappeared.  Consider lemmas not_less
  1116 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1117 
  1118 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1119 (whose purpose mainly is for various fold_set functionals) have been
  1120 abandoned in favor of the existing algebraic classes
  1121 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1122 lower_semilattice (resp. upper_semilattice) and linorder.
  1123 INCOMPATIBILITY.
  1124 
  1125 * Theory Transitive_Closure: induct and cases rules now declare proper
  1126 case_names ("base" and "step").  INCOMPATIBILITY.
  1127 
  1128 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1129 lattices.  The form set-specific version is available as
  1130 Inductive.lfp_ordinal_induct_set.
  1131 
  1132 * Renamed theorems "power.simps" to "power_int.simps".
  1133 INCOMPATIBILITY.
  1134 
  1135 * Class semiring_div provides basic abstract properties of semirings
  1136 with division and modulo operations.  Subsumes former class dvd_mod.
  1137 
  1138 * Merged theories IntDef, Numeral and IntArith into unified theory
  1139 Int.  INCOMPATIBILITY.
  1140 
  1141 * Theory Library/Code_Index: type "index" now represents natural
  1142 numbers rather than integers.  INCOMPATIBILITY.
  1143 
  1144 * New class "uminus" with operation "uminus" (split of from class
  1145 "minus" which now only has operation "minus", binary).
  1146 INCOMPATIBILITY.
  1147 
  1148 * Constants "card", "internal_split", "option_map" now with authentic
  1149 syntax.  INCOMPATIBILITY.
  1150 
  1151 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1152 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1153 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1154 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1155 Sup_set_def, le_def, less_def, option_map_def now with object
  1156 equality.  INCOMPATIBILITY.
  1157 
  1158 * Records. Removed K_record, and replaced it by pure lambda term
  1159 %x. c. The simplifier setup is now more robust against eta expansion.
  1160 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1161 
  1162 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1163 
  1164 * Library/ListVector: new theory of arithmetic vector operations.
  1165 
  1166 * Library/Order_Relation: new theory of various orderings as sets of
  1167 pairs.  Defines preorders, partial orders, linear orders and
  1168 well-orders on sets and on types.
  1169 
  1170 
  1171 *** ZF ***
  1172 
  1173 * Renamed some theories to allow to loading both ZF and HOL in the
  1174 same session:
  1175 
  1176   Datatype  -> Datatype_ZF
  1177   Inductive -> Inductive_ZF
  1178   Int       -> Int_ZF
  1179   IntDiv    -> IntDiv_ZF
  1180   Nat       -> Nat_ZF
  1181   List      -> List_ZF
  1182   Main      -> Main_ZF
  1183 
  1184 INCOMPATIBILITY: ZF theories that import individual theories below
  1185 Main might need to be adapted.  Regular theory Main is still
  1186 available, as trivial extension of Main_ZF.
  1187 
  1188 
  1189 *** ML ***
  1190 
  1191 * ML within Isar: antiquotation @{const name} or @{const
  1192 name(typargs)} produces statically-checked Const term.
  1193 
  1194 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1195 (of the same name).  Removed obsolete print command.
  1196 
  1197 * Removed obsolete "use_legacy_bindings" function.
  1198 
  1199 * The ``print mode'' is now a thread-local value derived from a global
  1200 template (the former print_mode reference), thus access becomes
  1201 non-critical.  The global print_mode reference is for session
  1202 management only; user-code should use print_mode_value,
  1203 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1204 
  1205 * Functions system/system_out provide a robust way to invoke external
  1206 shell commands, with propagation of interrupts (requires Poly/ML
  1207 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1208 
  1209 
  1210 *** System ***
  1211 
  1212 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1213 in accordance with Proof General 3.7, which prefers GNU emacs.
  1214 
  1215 * isatool tty runs Isabelle process with plain tty interaction;
  1216 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1217 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1218 
  1219 * isatool browser now works with Cygwin as well, using general
  1220 "javapath" function defined in Isabelle process environment.
  1221 
  1222 * YXML notation provides a simple and efficient alternative to
  1223 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1224 isatool yxml as described in the Isabelle system manual.
  1225 
  1226 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1227 provides general wrapper for managing an Isabelle process in a robust
  1228 fashion, with ``cooked'' output from stdin/stderr.
  1229 
  1230 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1231 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1232 
  1233 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1234 way of changing the user's settings is via
  1235 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1236 script.
  1237 
  1238 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1239 cores of the underlying machine, which is a good starting point for
  1240 optimal performance tuning.  The corresponding usedir option -M allows
  1241 "max" as an alias for "0".  WARNING: does not work on certain versions
  1242 of Mac OS (with Poly/ML 5.1).
  1243 
  1244 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1245 adverse effect of Isabelle flooding interactive front-ends (notably
  1246 ProofGeneral / XEmacs).
  1247 
  1248 
  1249 
  1250 New in Isabelle2007 (November 2007)
  1251 -----------------------------------
  1252 
  1253 *** General ***
  1254 
  1255 * More uniform information about legacy features, notably a
  1256 warning/error of "Legacy feature: ...", depending on the state of the
  1257 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1258 legacy features will disappear eventually.
  1259 
  1260 * Theory syntax: the header format ``theory A = B + C:'' has been
  1261 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1262 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1263 
  1264 * Theory syntax: the old non-Isar theory file format has been
  1265 discontinued altogether.  Note that ML proof scripts may still be used
  1266 with Isar theories; migration is usually quite simple with the ML
  1267 function use_legacy_bindings.  INCOMPATIBILITY.
  1268 
  1269 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1270 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1271 quotes.
  1272 
  1273 * Theory loader: be more serious about observing the static theory
  1274 header specifications (including optional directories), but not the
  1275 accidental file locations of previously successful loads.  The strict
  1276 update policy of former update_thy is now already performed by
  1277 use_thy, so the former has been removed; use_thys updates several
  1278 theories simultaneously, just as 'imports' within a theory header
  1279 specification, but without merging the results.  Potential
  1280 INCOMPATIBILITY: may need to refine theory headers and commands
  1281 ROOT.ML which depend on load order.
  1282 
  1283 * Theory loader: optional support for content-based file
  1284 identification, instead of the traditional scheme of full physical
  1285 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1286 (cf. the system manual).  The new scheme allows to work with
  1287 non-finished theories in persistent session images, such that source
  1288 files may be moved later on without requiring reloads.
  1289 
  1290 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1291 file (with the same base name as the theory) are considered a legacy
  1292 feature, which will disappear eventually. Even now, the theory loader
  1293 no longer maintains dependencies on such files.
  1294 
  1295 * Syntax: the scope for resolving ambiguities via type-inference is
  1296 now limited to individual terms, instead of whole simultaneous
  1297 specifications as before. This greatly reduces the complexity of the
  1298 syntax module and improves flexibility by separating parsing and
  1299 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1300 'fixes' etc.) are required in rare situations.
  1301 
  1302 * Syntax: constants introduced by new-style packages ('definition',
  1303 'abbreviation' etc.) are passed through the syntax module in
  1304 ``authentic mode''. This means that associated mixfix annotations
  1305 really stick to such constants, independently of potential name space
  1306 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1307 trees are represented slightly differently, may need to adapt syntax
  1308 translations accordingly. Use CONST marker in 'translations' and
  1309 @{const_syntax} antiquotation in 'parse_translation' etc.
  1310 
  1311 * Legacy goal package: reduced interface to the bare minimum required
  1312 to keep existing proof scripts running.  Most other user-level
  1313 functions are now part of the OldGoals structure, which is *not* open
  1314 by default (consider isatool expandshort before open OldGoals).
  1315 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1316 these tend to cause confusion about the actual goal (!) context being
  1317 used here, which is not necessarily the same as the_context().
  1318 
  1319 * Command 'find_theorems': supports "*" wild-card in "name:"
  1320 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1321 support a specific search form (see ProofGeneral/CHANGES).
  1322 
  1323 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1324 by default, which means that "prems" (and also "fixed variables") are
  1325 suppressed from proof state output.  Note that the ProofGeneral
  1326 settings mechanism allows to change and save options persistently, but
  1327 older versions of Isabelle will fail to start up if a negative prems
  1328 limit is imposed.
  1329 
  1330 * Local theory targets may be specified by non-nested blocks of
  1331 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1332 contain definitions, theorems etc., including any derived mechanism
  1333 that has been implemented on top of these primitives.  This concept
  1334 generalizes the existing ``theorem (in ...)'' towards more versatility
  1335 and scalability.
  1336 
  1337 * Proof General interface: proper undo of final 'end' command;
  1338 discontinued Isabelle/classic mode (ML proof scripts).
  1339 
  1340 
  1341 *** Document preparation ***
  1342 
  1343 * Added antiquotation @{theory name} which prints the given name,
  1344 after checking that it refers to a valid ancestor theory in the
  1345 current context.
  1346 
  1347 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1348 check the given source text as ML type/structure, printing verbatim.
  1349 
  1350 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1351 "c args == rhs" given in the current context.  (Any number of
  1352 arguments may be given on the LHS.)
  1353 
  1354 
  1355 *** Pure ***
  1356 
  1357 * The 'class' package offers a combination of axclass and locale to
  1358 achieve Haskell-like type classes in Isabelle.  Definitions and
  1359 theorems within a class context produce both relative results (with
  1360 implicit parameters according to the locale context), and polymorphic
  1361 constants with qualified polymorphism (according to the class
  1362 context).  Within the body context of a 'class' target, a separate
  1363 syntax layer ("user space type system") takes care of converting
  1364 between global polymorphic consts and internal locale representation.
  1365 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1366 "isatool doc classes" provides a tutorial.
  1367 
  1368 * Generic code generator framework allows to generate executable
  1369 code for ML and Haskell (including Isabelle classes).  A short usage
  1370 sketch:
  1371 
  1372     internal compilation:
  1373         export_code <list of constants (term syntax)> in SML
  1374     writing SML code to a file:
  1375         export_code <list of constants (term syntax)> in SML <filename>
  1376     writing OCaml code to a file:
  1377         export_code <list of constants (term syntax)> in OCaml <filename>
  1378     writing Haskell code to a bunch of files:
  1379         export_code <list of constants (term syntax)> in Haskell <filename>
  1380 
  1381     evaluating closed propositions to True/False using code generation:
  1382         method ``eval''
  1383 
  1384 Reasonable default setup of framework in HOL.
  1385 
  1386 Theorem attributs for selecting and transforming function equations theorems:
  1387 
  1388     [code fun]:        select a theorem as function equation for a specific constant
  1389     [code fun del]:    deselect a theorem as function equation for a specific constant
  1390     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1391     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1392 
  1393 User-defined serializations (target in {SML, OCaml, Haskell}):
  1394 
  1395     code_const <and-list of constants (term syntax)>
  1396       {(target) <and-list of const target syntax>}+
  1397 
  1398     code_type <and-list of type constructors>
  1399       {(target) <and-list of type target syntax>}+
  1400 
  1401     code_instance <and-list of instances>
  1402       {(target)}+
  1403         where instance ::= <type constructor> :: <class>
  1404 
  1405     code_class <and_list of classes>
  1406       {(target) <and-list of class target syntax>}+
  1407         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1408 
  1409 code_instance and code_class only are effective to target Haskell.
  1410 
  1411 For example usage see src/HOL/ex/Codegenerator.thy and
  1412 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1413 generation from Isabelle/HOL theories is available via "isatool doc
  1414 codegen".
  1415 
  1416 * Code generator: consts in 'consts_code' Isar commands are now
  1417 referred to by usual term syntax (including optional type
  1418 annotations).
  1419 
  1420 * Command 'no_translations' removes translation rules from theory
  1421 syntax.
  1422 
  1423 * Overloaded definitions are now actually checked for acyclic
  1424 dependencies.  The overloading scheme is slightly more general than
  1425 that of Haskell98, although Isabelle does not demand an exact
  1426 correspondence to type class and instance declarations.
  1427 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1428 exotic versions of overloading -- at the discretion of the user!
  1429 
  1430 Polymorphic constants are represented via type arguments, i.e. the
  1431 instantiation that matches an instance against the most general
  1432 declaration given in the signature.  For example, with the declaration
  1433 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1434 as c(nat).  Overloading is essentially simultaneous structural
  1435 recursion over such type arguments.  Incomplete specification patterns
  1436 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1437 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1438 Command 'print_theory' outputs the normalized system of recursive
  1439 equations, see section "definitions".
  1440 
  1441 * Configuration options are maintained within the theory or proof
  1442 context (with name and type bool/int/string), providing a very simple
  1443 interface to a poor-man's version of general context data.  Tools may
  1444 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1445 these values using Config.get etc.  Users may change options via an
  1446 associated attribute of the same name.  This form of context
  1447 declaration works particularly well with commands 'declare' or
  1448 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1449 very easy to avoid global references, which would not observe Isar
  1450 toplevel undo/redo and fail to work with multithreading.
  1451 
  1452 Various global ML references of Pure and HOL have been turned into
  1453 configuration options:
  1454 
  1455   Unify.search_bound		unify_search_bound
  1456   Unify.trace_bound		unify_trace_bound
  1457   Unify.trace_simp		unify_trace_simp
  1458   Unify.trace_types		unify_trace_types
  1459   Simplifier.simp_depth_limit	simp_depth_limit
  1460   Blast.depth_limit		blast_depth_limit
  1461   DatatypeProp.dtK		datatype_distinctness_limit
  1462   fast_arith_neq_limit  	fast_arith_neq_limit
  1463   fast_arith_split_limit	fast_arith_split_limit
  1464 
  1465 * Named collections of theorems may be easily installed as context
  1466 data using the functor NamedThmsFun (see also
  1467 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1468 attributes; there is also a toplevel print command.  This facility is
  1469 just a common case of general context data, which is the preferred way
  1470 for anything more complex than just a list of facts in canonical
  1471 order.
  1472 
  1473 * Isar: command 'declaration' augments a local theory by generic
  1474 declaration functions written in ML.  This enables arbitrary content
  1475 being added to the context, depending on a morphism that tells the
  1476 difference of the original declaration context wrt. the application
  1477 context encountered later on.
  1478 
  1479 * Isar: proper interfaces for simplification procedures.  Command
  1480 'simproc_setup' declares named simprocs (with match patterns, and body
  1481 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1482 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1483 
  1484 * Isar: an extra pair of brackets around attribute declarations
  1485 abbreviates a theorem reference involving an internal dummy fact,
  1486 which will be ignored later --- only the effect of the attribute on
  1487 the background context will persist.  This form of in-place
  1488 declarations is particularly useful with commands like 'declare' and
  1489 'using', for example ``have A using [[simproc a]] by simp''.
  1490 
  1491 * Isar: method "assumption" (and implicit closing of subproofs) now
  1492 takes simple non-atomic goal assumptions into account: after applying
  1493 an assumption as a rule the resulting subgoals are solved by atomic
  1494 assumption steps.  This is particularly useful to finish 'obtain'
  1495 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1496 without referring to the original premise "!!x. P x ==> thesis" in the
  1497 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1498 more permissive.
  1499 
  1500 * Isar: implicit use of prems from the Isar proof context is
  1501 considered a legacy feature.  Common applications like ``have A .''
  1502 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1503 referencing facts explicitly here improves readability and
  1504 maintainability of proof texts.
  1505 
  1506 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1507 the obtained context from the course of reasoning!  For example:
  1508 
  1509   assume "EX x y. A x & B y"   -- "any previous fact"
  1510   then guess x and y by clarify
  1511 
  1512 This technique is potentially adventurous, depending on the facts and
  1513 proof tools being involved here.
  1514 
  1515 * Isar: known facts from the proof context may be specified as literal
  1516 propositions, using ASCII back-quote syntax.  This works wherever
  1517 named facts used to be allowed so far, in proof commands, proof
  1518 methods, attributes etc.  Literal facts are retrieved from the context
  1519 according to unification of type and term parameters.  For example,
  1520 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1521 theorems in the current context, then these are valid literal facts:
  1522 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1523 
  1524 There is also a proof method "fact" which does the same composition
  1525 for explicit goal states, e.g. the following proof texts coincide with
  1526 certain special cases of literal facts:
  1527 
  1528   have "A" by fact                 ==  note `A`
  1529   have "A ==> B" by fact           ==  note `A ==> B`
  1530   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1531   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1532 
  1533 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1534 outer syntax.  Thus symbolic identifiers may be used without
  1535 additional white space in declarations like this: ``assume *: A''.
  1536 
  1537 * Isar: 'print_facts' prints all local facts of the current context,
  1538 both named and unnamed ones.
  1539 
  1540 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1541 
  1542   def x == "t" and y == "u"
  1543 
  1544 * Isar: added command 'unfolding', which is structurally similar to
  1545 'using', but affects both the goal state and facts by unfolding given
  1546 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1547 'unfolded' attribute may be replaced by first-class proof text.
  1548 
  1549 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1550 and command 'unfolding' now all support object-level equalities
  1551 (potentially conditional).  The underlying notion of rewrite rule is
  1552 analogous to the 'rule_format' attribute, but *not* that of the
  1553 Simplifier (which is usually more generous).
  1554 
  1555 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1556 premises of a theorem by n. Useful in conjunction with drule.
  1557 
  1558 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1559 method expression within a sandbox consisting of the first N
  1560 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1561 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1562 simplifies all new goals that emerge from applying rule foo to the
  1563 originally first one.
  1564 
  1565 * Isar: schematic goals are no longer restricted to higher-order
  1566 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1567 expected.
  1568 
  1569 * Isar: the conclusion of a long theorem statement is now either
  1570 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1571 (essentially a disjunction of cases with local parameters and
  1572 assumptions).  The latter allows to express general elimination rules
  1573 adequately; in this notation common elimination rules look like this:
  1574 
  1575   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1576     assumes "EX x. P x"
  1577     obtains x where "P x"
  1578 
  1579   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1580     assumes "A & B"
  1581     obtains A and B
  1582 
  1583   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1584     assumes "A | B"
  1585     obtains
  1586       A
  1587     | B
  1588 
  1589 The subsequent classical rules even refer to the formal "thesis"
  1590 explicitly:
  1591 
  1592   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1593     obtains "~ thesis"
  1594 
  1595   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1596     obtains "thesis ==> something"
  1597 
  1598 The actual proof of an 'obtains' statement is analogous to that of the
  1599 Isar proof element 'obtain', only that there may be several cases.
  1600 Optional case names may be specified in parentheses; these will be
  1601 available both in the present proof and as annotations in the
  1602 resulting rule, for later use with the 'cases' method (cf. attribute
  1603 case_names).
  1604 
  1605 * Isar: the assumptions of a long theorem statement are available as
  1606 "assms" fact in the proof context.  This is more appropriate than the
  1607 (historical) "prems", which refers to all assumptions of the current
  1608 context, including those from the target locale, proof body etc.
  1609 
  1610 * Isar: 'print_statement' prints theorems from the current theory or
  1611 proof context in long statement form, according to the syntax of a
  1612 top-level lemma.
  1613 
  1614 * Isar: 'obtain' takes an optional case name for the local context
  1615 introduction rule (default "that").
  1616 
  1617 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1618 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1619 to occur.
  1620 
  1621 * Pure: syntax "CONST name" produces a fully internalized constant
  1622 according to the current context.  This is particularly useful for
  1623 syntax translations that should refer to internal constant
  1624 representations independently of name spaces.
  1625 
  1626 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1627 instead of "FOO ". This allows multiple binder declarations to coexist
  1628 in the same context.  INCOMPATIBILITY.
  1629 
  1630 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1631 primitive that also works in a locale context (both for constants and
  1632 fixed variables). Type declaration and internal syntactic representation
  1633 of given constants retrieved from the context. Likewise, the
  1634 'no_notation' command allows to remove given syntax annotations from the
  1635 current context.
  1636 
  1637 * Isar/locales: new derived specification elements 'axiomatization',
  1638 'definition', 'abbreviation', which support type-inference, admit
  1639 object-level specifications (equality, equivalence).  See also the
  1640 isar-ref manual.  Examples:
  1641 
  1642   axiomatization
  1643     eq  (infix "===" 50) where
  1644     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1645 
  1646   definition "f x y = x + y + 1"
  1647   definition g where "g x = f x x"
  1648 
  1649   abbreviation
  1650     neq  (infix "=!=" 50) where
  1651     "x =!= y == ~ (x === y)"
  1652 
  1653 These specifications may be also used in a locale context.  Then the
  1654 constants being introduced depend on certain fixed parameters, and the
  1655 constant name is qualified by the locale base name.  An internal
  1656 abbreviation takes care for convenient input and output, making the
  1657 parameters implicit and using the original short name.  See also
  1658 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1659 entities from a monomorphic theory.
  1660 
  1661 Presently, abbreviations are only available 'in' a target locale, but
  1662 not inherited by general import expressions.  Also note that
  1663 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1664 'translations' in common applications.  The "no_abbrevs" print mode
  1665 prevents folding of abbreviations in term output.
  1666 
  1667 Concrete syntax is attached to specified constants in internal form,
  1668 independently of name spaces.  The parse tree representation is
  1669 slightly different -- use 'notation' instead of raw 'syntax', and
  1670 'translations' with explicit "CONST" markup to accommodate this.
  1671 
  1672 * Pure/Isar: unified syntax for new-style specification mechanisms
  1673 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1674 full type inference and dummy patterns ("_").  For example:
  1675 
  1676   definition "K x _ = x"
  1677 
  1678   inductive conj for A B
  1679   where "A ==> B ==> conj A B"
  1680 
  1681 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1682 the current context.  Print mode "no_abbrevs" prevents inversion of
  1683 abbreviations on output.
  1684 
  1685 * Isar/locales: improved parameter handling: use of locales "var" and
  1686 "struct" no longer necessary; - parameter renamings are no longer
  1687 required to be injective.  For example, this allows to define
  1688 endomorphisms as locale endom = homom mult mult h.
  1689 
  1690 * Isar/locales: changed the way locales with predicates are defined.
  1691 Instead of accumulating the specification, the imported expression is
  1692 now an interpretation.  INCOMPATIBILITY: different normal form of
  1693 locale expressions.  In particular, in interpretations of locales with
  1694 predicates, goals repesenting already interpreted fragments are not
  1695 removed automatically.  Use methods `intro_locales' and
  1696 `unfold_locales'; see below.
  1697 
  1698 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1699 provide backward reasoning on locales predicates.  The methods are
  1700 aware of interpretations and discharge corresponding goals.
  1701 `intro_locales' is less aggressive then `unfold_locales' and does not
  1702 unfold predicates to assumptions.
  1703 
  1704 * Isar/locales: the order in which locale fragments are accumulated
  1705 has changed.  This enables to override declarations from fragments due
  1706 to interpretations -- for example, unwanted simp rules.
  1707 
  1708 * Isar/locales: interpretation in theories and proof contexts has been
  1709 extended.  One may now specify (and prove) equations, which are
  1710 unfolded in interpreted theorems.  This is useful for replacing
  1711 defined concepts (constants depending on locale parameters) by
  1712 concepts already existing in the target context.  Example:
  1713 
  1714   interpretation partial_order ["op <= :: [int, int] => bool"]
  1715     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1716 
  1717 Typically, the constant `partial_order.less' is created by a
  1718 definition specification element in the context of locale
  1719 partial_order.
  1720 
  1721 * Method "induct": improved internal context management to support
  1722 local fixes and defines on-the-fly. Thus explicit meta-level
  1723 connectives !!  and ==> are rarely required anymore in inductive goals
  1724 (using object-logic connectives for this purpose has been long
  1725 obsolete anyway). Common proof patterns are explained in
  1726 src/HOL/Induct/Common_Patterns.thy, see also
  1727 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1728 examples.
  1729 
  1730 * Method "induct": improved handling of simultaneous goals. Instead of
  1731 introducing object-level conjunction, the statement is now split into
  1732 several conclusions, while the corresponding symbolic cases are nested
  1733 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1734 see src/HOL/Induct/Common_Patterns.thy, for example.
  1735 
  1736 * Method "induct": mutual induction rules are now specified as a list
  1737 of rule sharing the same induction cases. HOL packages usually provide
  1738 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1739 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1740 mutual induction rules differently, i.e. like this:
  1741 
  1742   (induct rule: foo_bar.inducts)
  1743   (induct set: foo bar)
  1744   (induct pred: foo bar)
  1745   (induct type: foo bar)
  1746 
  1747 The ML function ProjectRule.projections turns old-style rules into the
  1748 new format.
  1749 
  1750 * Method "coinduct": dual of induction, see
  1751 src/HOL/Library/Coinductive_List.thy for various examples.
  1752 
  1753 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1754 considered a legacy feature.
  1755 
  1756 * Attribute "symmetric" produces result with standardized schematic
  1757 variables (index 0).  Potential INCOMPATIBILITY.
  1758 
  1759 * Simplifier: by default the simplifier trace only shows top level
  1760 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1761 default. Thus there is less danger of being flooded by the trace. The
  1762 trace indicates where parts have been suppressed.
  1763   
  1764 * Provers/classical: removed obsolete classical version of elim_format
  1765 attribute; classical elim/dest rules are now treated uniformly when
  1766 manipulating the claset.
  1767 
  1768 * Provers/classical: stricter checks to ensure that supplied intro,
  1769 dest and elim rules are well-formed; dest and elim rules must have at
  1770 least one premise.
  1771 
  1772 * Provers/classical: attributes dest/elim/intro take an optional
  1773 weight argument for the rule (just as the Pure versions).  Weights are
  1774 ignored by automated tools, but determine the search order of single
  1775 rule steps.
  1776 
  1777 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1778 where the body does not mention the bound variable.  Note that dummy
  1779 patterns implicitly depend on their context of bounds, which makes
  1780 "{_. _}" match any set comprehension as expected.  Potential
  1781 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1782 constant "_idtdummy" in the binding position.
  1783 
  1784 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1785 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1786 for example "A -> B" => "Pi A (%_. B)".
  1787 
  1788 * Pure: 'class_deps' command visualizes the subclass relation, using
  1789 the graph browser tool.
  1790 
  1791 * Pure: 'print_theory' now suppresses certain internal declarations by
  1792 default; use '!' option for full details.
  1793 
  1794 
  1795 *** HOL ***
  1796 
  1797 * Method "metis" proves goals by applying the Metis general-purpose
  1798 resolution prover (see also http://gilith.com/software/metis/).
  1799 Examples are in the directory MetisExamples.  WARNING: the
  1800 Isabelle/HOL-Metis integration does not yet work properly with
  1801 multi-threading.
  1802   
  1803 * Command 'sledgehammer' invokes external automatic theorem provers as
  1804 background processes.  It generates calls to the "metis" method if
  1805 successful. These can be pasted into the proof.  Users do not have to
  1806 wait for the automatic provers to return.  WARNING: does not really
  1807 work with multi-threading.
  1808 
  1809 * New "auto_quickcheck" feature tests outermost goal statements for
  1810 potential counter-examples.  Controlled by ML references
  1811 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1812 5000 milliseconds).  Fails silently if statements is outside of
  1813 executable fragment, or any other codgenerator problem occurs.
  1814 
  1815 * New constant "undefined" with axiom "undefined x = undefined".
  1816 
  1817 * Added class "HOL.eq", allowing for code generation with polymorphic
  1818 equality.
  1819 
  1820 * Some renaming of class constants due to canonical name prefixing in
  1821 the new 'class' package:
  1822 
  1823     HOL.abs ~> HOL.abs_class.abs
  1824     HOL.divide ~> HOL.divide_class.divide
  1825     0 ~> HOL.zero_class.zero
  1826     1 ~> HOL.one_class.one
  1827     op + ~> HOL.plus_class.plus
  1828     op - ~> HOL.minus_class.minus
  1829     uminus ~> HOL.minus_class.uminus
  1830     op * ~> HOL.times_class.times
  1831     op < ~> HOL.ord_class.less
  1832     op <= > HOL.ord_class.less_eq
  1833     Nat.power ~> Power.power_class.power
  1834     Nat.size ~> Nat.size_class.size
  1835     Numeral.number_of ~> Numeral.number_class.number_of
  1836     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1837     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1838     Orderings.min ~> Orderings.ord_class.min
  1839     Orderings.max ~> Orderings.ord_class.max
  1840     Divides.op div ~> Divides.div_class.div
  1841     Divides.op mod ~> Divides.div_class.mod
  1842     Divides.op dvd ~> Divides.div_class.dvd
  1843 
  1844 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1845 
  1846 a) User-defined constants using any of the names "plus", "minus",
  1847 "times", "less" or "less_eq". The standard syntax translations for
  1848 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1849 names.
  1850 
  1851 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1852 INCOMPATIBILITY: use more specific names.
  1853 
  1854 c) Permutative equations (e.g. "a + b = b + a")
  1855 Since the change of names also changes the order of terms, permutative
  1856 rewrite rules may get applied in a different order. Experience shows
  1857 that this is rarely the case (only two adaptions in the whole Isabelle
  1858 distribution).  INCOMPATIBILITY: rewrite proofs
  1859 
  1860 d) ML code directly refering to constant names
  1861 This in general only affects hand-written proof tactics, simprocs and
  1862 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1863 Consider using @{const_name} antiquotation.
  1864 
  1865 * New class "default" with associated constant "default".
  1866 
  1867 * Function "sgn" is now overloaded and available on int, real, complex
  1868 (and other numeric types), using class "sgn".  Two possible defs of
  1869 sgn are given as equational assumptions in the classes sgn_if and
  1870 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1871 INCOMPATIBILITY.
  1872 
  1873 * Locale "partial_order" now unified with class "order" (cf. theory
  1874 Orderings), added parameter "less".  INCOMPATIBILITY.
  1875 
  1876 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1877 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1878 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1879 
  1880 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1881 changed order of proof goals in instance proofs.
  1882 
  1883 * The transitivity reasoner for partial and linear orders is set up
  1884 for classes "order" and "linorder".  Instances of the reasoner are available
  1885 in all contexts importing or interpreting the corresponding locales.
  1886 Method "order" invokes the reasoner separately; the reasoner
  1887 is also integrated with the Simplifier as a solver.  Diagnostic
  1888 command 'print_orders' shows the available instances of the reasoner
  1889 in the current context.
  1890 
  1891 * Localized monotonicity predicate in theory "Orderings"; integrated
  1892 lemmas max_of_mono and min_of_mono with this predicate.
  1893 INCOMPATIBILITY.
  1894 
  1895 * Formulation of theorem "dense" changed slightly due to integration
  1896 with new class dense_linear_order.
  1897 
  1898 * Uniform lattice theory development in HOL.
  1899 
  1900     constants "meet" and "join" now named "inf" and "sup"
  1901     constant "Meet" now named "Inf"
  1902 
  1903     classes "meet_semilorder" and "join_semilorder" now named
  1904       "lower_semilattice" and "upper_semilattice"
  1905     class "lorder" now named "lattice"
  1906     class "comp_lat" now named "complete_lattice"
  1907 
  1908     Instantiation of lattice classes allows explicit definitions
  1909     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1910 
  1911   INCOMPATIBILITY.  Theorem renames:
  1912 
  1913     meet_left_le            ~> inf_le1
  1914     meet_right_le           ~> inf_le2
  1915     join_left_le            ~> sup_ge1
  1916     join_right_le           ~> sup_ge2
  1917     meet_join_le            ~> inf_sup_ord
  1918     le_meetI                ~> le_infI
  1919     join_leI                ~> le_supI
  1920     le_meet                 ~> le_inf_iff
  1921     le_join                 ~> ge_sup_conv
  1922     meet_idempotent         ~> inf_idem
  1923     join_idempotent         ~> sup_idem
  1924     meet_comm               ~> inf_commute
  1925     join_comm               ~> sup_commute
  1926     meet_leI1               ~> le_infI1
  1927     meet_leI2               ~> le_infI2
  1928     le_joinI1               ~> le_supI1
  1929     le_joinI2               ~> le_supI2
  1930     meet_assoc              ~> inf_assoc
  1931     join_assoc              ~> sup_assoc
  1932     meet_left_comm          ~> inf_left_commute
  1933     meet_left_idempotent    ~> inf_left_idem
  1934     join_left_comm          ~> sup_left_commute
  1935     join_left_idempotent    ~> sup_left_idem
  1936     meet_aci                ~> inf_aci
  1937     join_aci                ~> sup_aci
  1938     le_def_meet             ~> le_iff_inf
  1939     le_def_join             ~> le_iff_sup
  1940     join_absorp2            ~> sup_absorb2
  1941     join_absorp1            ~> sup_absorb1
  1942     meet_absorp1            ~> inf_absorb1
  1943     meet_absorp2            ~> inf_absorb2
  1944     meet_join_absorp        ~> inf_sup_absorb
  1945     join_meet_absorp        ~> sup_inf_absorb
  1946     distrib_join_le         ~> distrib_sup_le
  1947     distrib_meet_le         ~> distrib_inf_le
  1948 
  1949     add_meet_distrib_left   ~> add_inf_distrib_left
  1950     add_join_distrib_left   ~> add_sup_distrib_left
  1951     is_join_neg_meet        ~> is_join_neg_inf
  1952     is_meet_neg_join        ~> is_meet_neg_sup
  1953     add_meet_distrib_right  ~> add_inf_distrib_right
  1954     add_join_distrib_right  ~> add_sup_distrib_right
  1955     add_meet_join_distribs  ~> add_sup_inf_distribs
  1956     join_eq_neg_meet        ~> sup_eq_neg_inf
  1957     meet_eq_neg_join        ~> inf_eq_neg_sup
  1958     add_eq_meet_join        ~> add_eq_inf_sup
  1959     meet_0_imp_0            ~> inf_0_imp_0
  1960     join_0_imp_0            ~> sup_0_imp_0
  1961     meet_0_eq_0             ~> inf_0_eq_0
  1962     join_0_eq_0             ~> sup_0_eq_0
  1963     neg_meet_eq_join        ~> neg_inf_eq_sup
  1964     neg_join_eq_meet        ~> neg_sup_eq_inf
  1965     join_eq_if              ~> sup_eq_if
  1966 
  1967     mono_meet               ~> mono_inf
  1968     mono_join               ~> mono_sup
  1969     meet_bool_eq            ~> inf_bool_eq
  1970     join_bool_eq            ~> sup_bool_eq
  1971     meet_fun_eq             ~> inf_fun_eq
  1972     join_fun_eq             ~> sup_fun_eq
  1973     meet_set_eq             ~> inf_set_eq
  1974     join_set_eq             ~> sup_set_eq
  1975     meet1_iff               ~> inf1_iff
  1976     meet2_iff               ~> inf2_iff
  1977     meet1I                  ~> inf1I
  1978     meet2I                  ~> inf2I
  1979     meet1D1                 ~> inf1D1
  1980     meet2D1                 ~> inf2D1
  1981     meet1D2                 ~> inf1D2
  1982     meet2D2                 ~> inf2D2
  1983     meet1E                  ~> inf1E
  1984     meet2E                  ~> inf2E
  1985     join1_iff               ~> sup1_iff
  1986     join2_iff               ~> sup2_iff
  1987     join1I1                 ~> sup1I1
  1988     join2I1                 ~> sup2I1
  1989     join1I1                 ~> sup1I1
  1990     join2I2                 ~> sup1I2
  1991     join1CI                 ~> sup1CI
  1992     join2CI                 ~> sup2CI
  1993     join1E                  ~> sup1E
  1994     join2E                  ~> sup2E
  1995 
  1996     is_meet_Meet            ~> is_meet_Inf
  1997     Meet_bool_def           ~> Inf_bool_def
  1998     Meet_fun_def            ~> Inf_fun_def
  1999     Meet_greatest           ~> Inf_greatest
  2000     Meet_lower              ~> Inf_lower
  2001     Meet_set_def            ~> Inf_set_def
  2002 
  2003     Sup_def                 ~> Sup_Inf
  2004     Sup_bool_eq             ~> Sup_bool_def
  2005     Sup_fun_eq              ~> Sup_fun_def
  2006     Sup_set_eq              ~> Sup_set_def
  2007 
  2008     listsp_meetI            ~> listsp_infI
  2009     listsp_meet_eq          ~> listsp_inf_eq
  2010 
  2011     meet_min                ~> inf_min
  2012     join_max                ~> sup_max
  2013 
  2014 * Added syntactic class "size"; overloaded constant "size" now has
  2015 type "'a::size ==> bool"
  2016 
  2017 * Internal reorganisation of `size' of datatypes: size theorems
  2018 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2019 simplification rules by default!); theorems "prod.size" now named
  2020 "*.size".
  2021 
  2022 * Class "div" now inherits from class "times" rather than "type".
  2023 INCOMPATIBILITY.
  2024 
  2025 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2026 Linorder etc.  have disappeared; operations defined in terms of
  2027 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2028 
  2029 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2030 
  2031 * HOL-Word: New extensive library and type for generic, fixed size
  2032 machine words, with arithemtic, bit-wise, shifting and rotating
  2033 operations, reflection into int, nat, and bool lists, automation for
  2034 linear arithmetic (by automatic reflection into nat or int), including
  2035 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2036 arithmetic type classes, supporting automatic simplification of
  2037 numerals on all operations.
  2038 
  2039 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2040 
  2041 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2042 
  2043 * Code generator library theories:
  2044   - Code_Integer represents HOL integers by big integer literals in target
  2045     languages.
  2046   - Code_Char represents HOL characters by character literals in target
  2047     languages.
  2048   - Code_Char_chr like Code_Char, but also offers treatment of character
  2049     codes; includes Code_Integer.
  2050   - Executable_Set allows to generate code for finite sets using lists.
  2051   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2052     denominator).
  2053   - Executable_Real implements a subset of real numbers, namly those
  2054     representable by rational numbers.
  2055   - Efficient_Nat implements natural numbers by integers, which in general will
  2056     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2057     includes Code_Integer.
  2058   - Code_Index provides an additional datatype index which is mapped to
  2059     target-language built-in integers.
  2060   - Code_Message provides an additional datatype message_string which is isomorphic to
  2061     strings; messages are mapped to target-language strings.
  2062 
  2063 * New package for inductive predicates
  2064 
  2065   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2066 
  2067     inductive
  2068       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2069       for z_1 :: U_1 and ... and z_n :: U_m
  2070     where
  2071       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2072     | ...
  2073 
  2074   with full support for type-inference, rather than
  2075 
  2076     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2077 
  2078     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2079     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2080 
  2081     inductive "s z_1 ... z_m"
  2082     intros
  2083       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2084       ...
  2085 
  2086   For backward compatibility, there is a wrapper allowing inductive
  2087   sets to be defined with the new package via
  2088 
  2089     inductive_set
  2090       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2091       for z_1 :: U_1 and ... and z_n :: U_m
  2092     where
  2093       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2094     | ...
  2095 
  2096   or
  2097 
  2098     inductive_set
  2099       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2100       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2101       for z_1 :: U_1 and ... and z_n :: U_m
  2102     where
  2103       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2104     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2105     | ...
  2106 
  2107   if the additional syntax "p ..." is required.
  2108 
  2109   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2110   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2111 
  2112   INCOMPATIBILITIES:
  2113 
  2114   - Since declaration and definition of inductive sets or predicates
  2115     is no longer separated, abbreviations involving the newly
  2116     introduced sets or predicates must be specified together with the
  2117     introduction rules after the 'where' keyword (see above), rather
  2118     than before the actual inductive definition.
  2119 
  2120   - The variables in induction and elimination rules are now
  2121     quantified in the order of their occurrence in the introduction
  2122     rules, rather than in alphabetical order. Since this may break
  2123     some proofs, these proofs either have to be repaired, e.g. by
  2124     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2125     statements of the form
  2126 
  2127       case (rule_i a_i_1 ... a_i_{k_i})
  2128 
  2129     or the old order of quantification has to be restored by explicitly adding
  2130     meta-level quantifiers in the introduction rules, i.e.
  2131 
  2132       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2133 
  2134   - The format of the elimination rules is now
  2135 
  2136       p z_1 ... z_m x_1 ... x_n ==>
  2137         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2138         ==> ... ==> P
  2139 
  2140     for predicates and
  2141 
  2142       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2143         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2144         ==> ... ==> P
  2145 
  2146     for sets rather than
  2147 
  2148       x : s z_1 ... z_m ==>
  2149         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2150         ==> ... ==> P
  2151 
  2152     This may require terms in goals to be expanded to n-tuples
  2153     (e.g. using case_tac or simplification with the split_paired_all
  2154     rule) before the above elimination rule is applicable.
  2155 
  2156   - The elimination or case analysis rules for (mutually) inductive
  2157     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2158     list of rules "p_1_..._p_k.elims" is no longer available.
  2159 
  2160 * New package "function"/"fun" for general recursive functions,
  2161 supporting mutual and nested recursion, definitions in local contexts,
  2162 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2163 for small examples, and the separate tutorial on the function
  2164 package. The old recdef "package" is still available as before, but
  2165 users are encouraged to use the new package.
  2166 
  2167 * Method "lexicographic_order" automatically synthesizes termination
  2168 relations as lexicographic combinations of size measures. 
  2169 
  2170 * Case-expressions allow arbitrary constructor-patterns (including
  2171 "_") and take their order into account, like in functional
  2172 programming.  Internally, this is translated into nested
  2173 case-expressions; missing cases are added and mapped to the predefined
  2174 constant "undefined". In complicated cases printing may no longer show
  2175 the original input but the internal form. Lambda-abstractions allow
  2176 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2177 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2178 variable.
  2179 
  2180 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2181 is an abbreviation for "of_nat :: nat => int". The simplification
  2182 rules for "of_nat" have been changed to work like "int" did
  2183 previously.  Potential INCOMPATIBILITY:
  2184   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2185   - of_nat_diff and of_nat_mult are no longer default simp rules
  2186 
  2187 * Method "algebra" solves polynomial equations over (semi)rings using
  2188 Groebner bases. The (semi)ring structure is defined by locales and the
  2189 tool setup depends on that generic context. Installing the method for
  2190 a specific type involves instantiating the locale and possibly adding
  2191 declarations for computation on the coefficients.  The method is
  2192 already instantiated for natural numbers and for the axiomatic class
  2193 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2194 CALCULEMUS 2007 for the general principles underlying this
  2195 architecture of context-aware proof-tools.
  2196 
  2197 * Method "ferrack" implements quantifier elimination over
  2198 special-purpose dense linear orders using locales (analogous to
  2199 "algebra"). The method is already installed for class
  2200 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2201 rat, etc.
  2202 
  2203 * Former constant "List.op @" now named "List.append".  Use ML
  2204 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2205 circumvent possible incompatibilities when working on ML level.
  2206 
  2207 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2208 
  2209 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2210 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2211 
  2212 * New syntax for Haskell-like list comprehension (input only), eg.
  2213 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2214 
  2215 * The special syntax for function "filter" has changed from [x :
  2216 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2217 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2218 
  2219 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2220 defined on nat only, as an abbreviation for [a..<Suc b]
  2221 INCOMPATIBILITY.
  2222 
  2223 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2224 
  2225 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2226 
  2227 * New lemma collection field_simps (an extension of ring_simps) for
  2228 manipulating (in)equations involving division. Multiplies with all
  2229 denominators that can be proved to be non-zero (in equations) or
  2230 positive/negative (in inequations).
  2231 
  2232 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2233 have been improved and renamed to ring_simps, group_simps and
  2234 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2235 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2236 
  2237 * Theory Library/Commutative_Ring: switched from recdef to function
  2238 package; constants add, mul, pow now curried.  Infix syntax for
  2239 algebraic operations.
  2240 
  2241 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2242 INCOMPATIBILITY.
  2243 
  2244 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2245 INCOMPATIBILITY.
  2246 
  2247 * HOL/records: generalised field-update to take a function on the
  2248 field rather than the new value: r(|A := x|) is translated to A_update
  2249 (K x) r The K-combinator that is internally used is called K_record.
  2250 INCOMPATIBILITY: Usage of the plain update functions has to be
  2251 adapted.
  2252  
  2253 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2254 * x = 0, which are required for a semiring.  Richer structures do not
  2255 inherit from semiring_0 anymore, because this property is a theorem
  2256 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2257 there is more to prove, but this is mostly trivial.
  2258 
  2259 * Class "recpower" is generalized to arbitrary monoids, not just
  2260 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2261 commutativity or semiring properties additionally.
  2262 
  2263 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2264 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2265 better use 'abbreviation'.
  2266 
  2267 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2268 
  2269 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2270 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2271 significant changes for setting up numeral syntax for types:
  2272   - New constants Numeral.pred and Numeral.succ instead
  2273       of former Numeral.bin_pred and Numeral.bin_succ.
  2274   - Use integer operations instead of bin_add, bin_mult and so on.
  2275   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2276   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2277 
  2278 See src/HOL/Integ/IntArith.thy for an example setup.
  2279 
  2280 * Command 'normal_form' computes the normal form of a term that may
  2281 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2282 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2283 heavy-duty computations because the functions are compiled to ML
  2284 first.  Correspondingly, a method "normalization" is provided.  See
  2285 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2286 
  2287 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2288 25 like -->); output depends on the "iff" print_mode, the default is
  2289 "A = B" (with priority 50).
  2290 
  2291 * Relations less (<) and less_eq (<=) are also available on type bool.
  2292 Modified syntax to disallow nesting without explicit parentheses,
  2293 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2294 INCOMPATIBILITY.
  2295 
  2296 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2297 
  2298 * Relation composition operator "op O" now has precedence 75 and binds
  2299 stronger than union and intersection. INCOMPATIBILITY.
  2300 
  2301 * The old set interval syntax "{m..n(}" (and relatives) has been
  2302 removed.  Use "{m..<n}" (and relatives) instead.
  2303 
  2304 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2305 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2306 ``declare [[simproc del: neq]]''.
  2307 
  2308 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2309 True/False.
  2310 
  2311 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2312 
  2313 * Theorem setsum_mult renamed to setsum_right_distrib.
  2314 
  2315 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2316 ``rule'' method.
  2317 
  2318 * Reimplemented methods "sat" and "satx", with several improvements:
  2319 goals no longer need to be stated as "<prems> ==> False", equivalences
  2320 (i.e. "=" on type bool) are handled, variable names of the form
  2321 "lit_<n>" are no longer reserved, significant speedup.
  2322 
  2323 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2324 zChaff is still supported as well.
  2325 
  2326 * 'inductive' and 'datatype': provide projections of mutual rules,
  2327 bundled as foo_bar.inducts;
  2328 
  2329 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2330 Library.
  2331 
  2332 * Library: moved theory Accessible_Part to main HOL.
  2333 
  2334 * Library: added theory Coinductive_List of potentially infinite lists
  2335 as greatest fixed-point.
  2336 
  2337 * Library: added theory AssocList which implements (finite) maps as
  2338 association lists.
  2339 
  2340 * Method "evaluation" solves goals (i.e. a boolean expression)
  2341 efficiently by compiling it to ML.  The goal is "proved" (via an
  2342 oracle) if it evaluates to True.
  2343 
  2344 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2345 also when invoked by the simplifier.  This results in the Simplifier
  2346 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2347 Configuration option fast_arith_split_limit=0 recovers the old
  2348 behavior.
  2349 
  2350 * Support for hex (0x20) and binary (0b1001) numerals.
  2351 
  2352 * New method: reify eqs (t), where eqs are equations for an
  2353 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2354 parameter, computes a term s::'b and a list xs::'a list and proves the
  2355 theorem I xs s = t. This is also known as reification or quoting. The
  2356 resulting theorem is applied to the subgoal to substitute t with I xs
  2357 s.  If t is omitted, the subgoal itself is reified.
  2358 
  2359 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2360 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2361 where f is supposed to be a computable function (in the sense of code
  2362 generattion). The method uses reify to compute s and xs as above then
  2363 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2364 r and finally gets the theorem t = r, which is again applied to the
  2365 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2366 
  2367 * Reflection: Automatic reification now handels binding, an example is
  2368 available in src/HOL/ex/ReflectionEx.thy
  2369 
  2370 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2371 command 'statespace' that is similar to 'record', but introduces an
  2372 abstract specification based on the locale infrastructure instead of
  2373 HOL types.  This leads to extra flexibility in composing state spaces,
  2374 in particular multiple inheritance and renaming of components.
  2375 
  2376 
  2377 *** HOL-Complex ***
  2378 
  2379 * Hyperreal: Functions root and sqrt are now defined on negative real
  2380 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2381 Nonnegativity side conditions have been removed from many lemmas, so
  2382 that more subgoals may now be solved by simplification; potential
  2383 INCOMPATIBILITY.
  2384 
  2385 * Real: new type classes formalize real normed vector spaces and
  2386 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2387 and norm :: 'a => real.
  2388 
  2389 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2390 reals into other types. The overloaded constant Reals :: 'a set is now
  2391 defined as range of_real; potential INCOMPATIBILITY.
  2392 
  2393 * Real: proper support for ML code generation, including 'quickcheck'.
  2394 Reals are implemented as arbitrary precision rationals.
  2395 
  2396 * Hyperreal: Several constants that previously worked only for the
  2397 reals have been generalized, so they now work over arbitrary vector
  2398 spaces. Type annotations may need to be added in some cases; potential
  2399 INCOMPATIBILITY.
  2400 
  2401   Infinitesimal  :: ('a::real_normed_vector) star set
  2402   HFinite        :: ('a::real_normed_vector) star set
  2403   HInfinite      :: ('a::real_normed_vector) star set
  2404   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2405   monad          :: ('a::real_normed_vector) star => 'a star set
  2406   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2407   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2408   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2409   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2410   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2411   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2412   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2413   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2414   sgn            :: 'a::real_normed_vector => 'a
  2415   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2416 
  2417 * Complex: Some complex-specific constants are now abbreviations for
  2418 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2419 hnorm.  Other constants have been entirely removed in favor of the
  2420 polymorphic versions (INCOMPATIBILITY):
  2421 
  2422   approx        <-- capprox
  2423   HFinite       <-- CFinite
  2424   HInfinite     <-- CInfinite
  2425   Infinitesimal <-- CInfinitesimal
  2426   monad         <-- cmonad
  2427   galaxy        <-- cgalaxy
  2428   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2429   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2430   (ns)deriv     <-- (ns)cderiv
  2431 
  2432 
  2433 *** HOL-Algebra ***
  2434 
  2435 * Formalisation of ideals and the quotient construction over rings.
  2436 
  2437 * Order and lattice theory no longer based on records.
  2438 INCOMPATIBILITY.
  2439 
  2440 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2441 greatest_closed.  INCOMPATIBILITY.
  2442 
  2443 * Method algebra is now set up via an attribute.  For examples see
  2444 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2445 of algebraic structures.
  2446 
  2447 * Renamed theory CRing to Ring.
  2448 
  2449 
  2450 *** HOL-Nominal ***
  2451 
  2452 * Substantial, yet incomplete support for nominal datatypes (binding
  2453 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2454 src/HOL/Nominal/Examples.  Prospective users should consult
  2455 http://isabelle.in.tum.de/nominal/
  2456 
  2457 
  2458 *** ML ***
  2459 
  2460 * ML basics: just one true type int, which coincides with IntInf.int
  2461 (even on SML/NJ).
  2462 
  2463 * ML within Isar: antiquotations allow to embed statically-checked
  2464 formal entities in the source, referring to the context available at
  2465 compile-time.  For example:
  2466 
  2467 ML {* @{sort "{zero,one}"} *}
  2468 ML {* @{typ "'a => 'b"} *}
  2469 ML {* @{term "%x. x"} *}
  2470 ML {* @{prop "x == y"} *}
  2471 ML {* @{ctyp "'a => 'b"} *}
  2472 ML {* @{cterm "%x. x"} *}
  2473 ML {* @{cprop "x == y"} *}
  2474 ML {* @{thm asm_rl} *}
  2475 ML {* @{thms asm_rl} *}
  2476 ML {* @{type_name c} *}
  2477 ML {* @{type_syntax c} *}
  2478 ML {* @{const_name c} *}
  2479 ML {* @{const_syntax c} *}
  2480 ML {* @{context} *}
  2481 ML {* @{theory} *}
  2482 ML {* @{theory Pure} *}
  2483 ML {* @{theory_ref} *}
  2484 ML {* @{theory_ref Pure} *}
  2485 ML {* @{simpset} *}
  2486 ML {* @{claset} *}
  2487 ML {* @{clasimpset} *}
  2488 
  2489 The same works for sources being ``used'' within an Isar context.
  2490 
  2491 * ML in Isar: improved error reporting; extra verbosity with
  2492 ML_Context.trace enabled.
  2493 
  2494 * Pure/General/table.ML: the join operations now works via exceptions
  2495 DUP/SAME instead of type option. This is simpler in simple cases, and
  2496 admits slightly more efficient complex applications.
  2497 
  2498 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2499 use Context.generic instead of just theory.
  2500 
  2501 * Pure: datatype Context.generic joins theory/Proof.context and
  2502 provides some facilities for code that works in either kind of
  2503 context, notably GenericDataFun for uniform theory and proof data.
  2504 
  2505 * Pure: simplified internal attribute type, which is now always
  2506 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2507 local (Proof.context) attributes have been discontinued, while
  2508 minimizing code duplication. Thm.rule_attribute and
  2509 Thm.declaration_attribute build canonical attributes; see also structure
  2510 Context for further operations on Context.generic, notably
  2511 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2512 declarations and definitions.
  2513 
  2514 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2515 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2516 init only required for impure data. INCOMPATIBILITY: empty really need
  2517 to be empty (no dependencies on theory content!)
  2518 
  2519 * Pure/kernel: consts certification ignores sort constraints given in
  2520 signature declarations. (This information is not relevant to the
  2521 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2522 potential INCOMPATIBILITY.
  2523 
  2524 * Pure: axiomatic type classes are now purely definitional, with
  2525 explicit proofs of class axioms and super class relations performed
  2526 internally. See Pure/axclass.ML for the main internal interfaces --
  2527 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2528 AxClass.axiomatize_class/classrel/arity supersede
  2529 Sign.add_classes/classrel/arities.
  2530 
  2531 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2532 global/local versions on theory vs. Proof.context have been
  2533 discontinued; Attrib.syntax and Method.syntax have been adapted
  2534 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2535 attributes, methods, etc.
  2536 
  2537 * Pure: several functions of signature "... -> theory -> theory * ..."
  2538 have been reoriented to "... -> theory -> ... * theory" in order to
  2539 allow natural usage in combination with the ||>, ||>>, |-> and
  2540 fold_map combinators.
  2541 
  2542 * Pure: official theorem names (closed derivations) and additional
  2543 comments (tags) are now strictly separate.  Name hints -- which are
  2544 maintained as tags -- may be attached any time without affecting the
  2545 derivation.
  2546 
  2547 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2548 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2549 achieve the old behaviour.
  2550 
  2551 * Pure: the "Goal" constant is now called "prop", supporting a
  2552 slightly more general idea of ``protecting'' meta-level rule
  2553 statements.
  2554 
  2555 * Pure: Logic.(un)varify only works in a global context, which is now
  2556 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2557 Logic.legacy_(un)varify as temporary workaround.
  2558 
  2559 * Pure: structure Name provides scalable operations for generating
  2560 internal variable names, notably Name.variants etc.  This replaces
  2561 some popular functions from term.ML:
  2562 
  2563   Term.variant		->  Name.variant
  2564   Term.variantlist	->  Name.variant_list
  2565   Term.invent_names	->  Name.invent_list
  2566 
  2567 Note that low-level renaming rarely occurs in new code -- operations
  2568 from structure Variable are used instead (see below).
  2569 
  2570 * Pure: structure Variable provides fundamental operations for proper
  2571 treatment of fixed/schematic variables in a context.  For example,
  2572 Variable.import introduces fixes for schematics of given facts and
  2573 Variable.export reverses the effect (up to renaming) -- this replaces
  2574 various freeze_thaw operations.
  2575 
  2576 * Pure: structure Goal provides simple interfaces for
  2577 init/conclude/finish and tactical prove operations (replacing former
  2578 Tactic.prove).  Goal.prove is the canonical way to prove results
  2579 within a given context; Goal.prove_global is a degraded version for
  2580 theory level goals, including a global Drule.standard.  Note that
  2581 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2582 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2583 in a locale context).
  2584 
  2585 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2586 and type checking (Syntax.check_term etc.), with common combinations
  2587 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2588 which are considered legacy and await removal.
  2589 
  2590 * Pure/Syntax: generic interfaces for type unchecking
  2591 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2592 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2593 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2594 available for convenience, but refer to the very same operations using
  2595 a mere theory instead of a full context.
  2596 
  2597 * Isar: simplified treatment of user-level errors, using exception
  2598 ERROR of string uniformly.  Function error now merely raises ERROR,
  2599 without any side effect on output channels.  The Isar toplevel takes
  2600 care of proper display of ERROR exceptions.  ML code may use plain
  2601 handle/can/try; cat_error may be used to concatenate errors like this:
  2602 
  2603   ... handle ERROR msg => cat_error msg "..."
  2604 
  2605 Toplevel ML code (run directly or through the Isar toplevel) may be
  2606 embedded into the Isar toplevel with exception display/debug like
  2607 this:
  2608 
  2609   Isar.toplevel (fn () => ...)
  2610 
  2611 INCOMPATIBILITY, removed special transform_error facilities, removed
  2612 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2613 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2614 -- use plain ERROR instead.
  2615 
  2616 * Isar: theory setup now has type (theory -> theory), instead of a
  2617 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2618 
  2619 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2620 ProofContext.debug/verbose flags.
  2621 
  2622 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2623 theory before entering a proof state.  Transactions now always see a
  2624 quasi-functional intermediate checkpoint, both in interactive and
  2625 batch mode.
  2626 
  2627 * Isar: simplified interfaces for outer syntax.  Renamed
  2628 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2629 OuterSyntax.add_parsers -- this functionality is now included in
  2630 OuterSyntax.command etc.  INCOMPATIBILITY.
  2631 
  2632 * Simplifier: the simpset of a running simplification process now
  2633 contains a proof context (cf. Simplifier.the_context), which is the
  2634 very context that the initial simpset has been retrieved from (by
  2635 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2636 (solver, looper etc.) may depend on arbitrary proof data.
  2637 
  2638 * Simplifier.inherit_context inherits the proof context (plus the
  2639 local bounds) of the current simplification process; any simproc
  2640 etc. that calls the Simplifier recursively should do this!  Removed
  2641 former Simplifier.inherit_bounds, which is already included here --
  2642 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2643 specify an explicit context using Simplifier.context/theory_context.
  2644 
  2645 * Simplifier/Classical Reasoner: more abstract interfaces
  2646 change_simpset/claset for modifying the simpset/claset reference of a
  2647 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2648 INCOMPATIBILITY.
  2649 
  2650 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2651 "Trueprop" etc.
  2652 
  2653 
  2654 *** System ***
  2655 
  2656 * settings: the default heap location within ISABELLE_HOME_USER now
  2657 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2658 Isabelle installations.
  2659 
  2660 * isabelle-process: option -S (secure mode) disables some critical
  2661 operations, notably runtime compilation and evaluation of ML source
  2662 code.
  2663 
  2664 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2665 
  2666 * Support for parallel execution, using native multicore support of
  2667 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2668 independent theories, according to the given theory header
  2669 specifications. The maximum number of worker threads is specified via
  2670 usedir option -M or the "max-threads" setting in Proof General. A
  2671 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2672 to 6 on a 8-core machine.  User-code needs to observe certain
  2673 guidelines for thread-safe programming, see appendix A in the Isar
  2674 Implementation manual.
  2675 
  2676 
  2677 
  2678 New in Isabelle2005 (October 2005)
  2679 ----------------------------------
  2680 
  2681 *** General ***
  2682 
  2683 * Theory headers: the new header syntax for Isar theories is
  2684 
  2685   theory <name>
  2686   imports <theory1> ... <theoryN>
  2687   uses <file1> ... <fileM>
  2688   begin
  2689 
  2690 where the 'uses' part is optional.  The previous syntax
  2691 
  2692   theory <name> = <theory1> + ... + <theoryN>:
  2693 
  2694 will disappear in the next release.  Use isatool fixheaders to convert
  2695 existing theory files.  Note that there is no change in ancient
  2696 non-Isar theories now, but these will disappear soon.
  2697 
  2698 * Theory loader: parent theories can now also be referred to via
  2699 relative and absolute paths.
  2700 
  2701 * Command 'find_theorems' searches for a list of criteria instead of a
  2702 list of constants. Known criteria are: intro, elim, dest, name:string,
  2703 simp:term, and any term. Criteria can be preceded by '-' to select
  2704 theorems that do not match. Intro, elim, dest select theorems that
  2705 match the current goal, name:s selects theorems whose fully qualified
  2706 name contain s, and simp:term selects all simplification rules whose
  2707 lhs match term.  Any other term is interpreted as pattern and selects
  2708 all theorems matching the pattern. Available in ProofGeneral under
  2709 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2710 
  2711   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2712 
  2713 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2714 matching the current goal as introduction rule and not having "HOL."
  2715 in their name (i.e. not being defined in theory HOL).
  2716 
  2717 * Command 'thms_containing' has been discontinued in favour of
  2718 'find_theorems'; INCOMPATIBILITY.
  2719 
  2720 * Communication with Proof General is now 8bit clean, which means that
  2721 Unicode text in UTF-8 encoding may be used within theory texts (both
  2722 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2723 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2724 
  2725   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2726   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2727 
  2728 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2729 Classical Reasoner.  Typical big applications run around 2 times
  2730 faster.
  2731 
  2732 
  2733 *** Document preparation ***
  2734 
  2735 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2736 of raw sources.  Only those symbols that do not require additional
  2737 LaTeX packages (depending on comments in isabellesym.sty) are
  2738 displayed properly, everything else is left verbatim.  isatool display
  2739 and isatool print are used as front ends (these are subject to the
  2740 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2741 
  2742 * Command tags control specific markup of certain regions of text,
  2743 notably folding and hiding.  Predefined tags include "theory" (for
  2744 theory begin and end), "proof" for proof commands, and "ML" for
  2745 commands involving ML code; the additional tags "visible" and
  2746 "invisible" are unused by default.  Users may give explicit tag
  2747 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2748 interpretation of tags is determined by the LaTeX job during document
  2749 preparation: see option -V of isatool usedir, or options -n and -t of
  2750 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2751 \isadroptag.
  2752 
  2753 Several document versions may be produced at the same time via isatool
  2754 usedir (the generated index.html will link all of them).  Typical
  2755 specifications include ''-V document=theory,proof,ML'' to present
  2756 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2757 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2758 these parts without any formal replacement text.  The Isabelle site
  2759 default settings produce ''document'' and ''outline'' versions as
  2760 specified above.
  2761 
  2762 * Several new antiquotations:
  2763 
  2764   @{term_type term} prints a term with its type annotated;
  2765 
  2766   @{typeof term} prints the type of a term;
  2767 
  2768   @{const const} is the same as @{term const}, but checks that the
  2769   argument is a known logical constant;
  2770 
  2771   @{term_style style term} and @{thm_style style thm} print a term or
  2772   theorem applying a "style" to it
  2773 
  2774   @{ML text}
  2775 
  2776 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2777 definitions, equations, inequations etc., 'concl' printing only the
  2778 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2779 to print the specified premise.  TermStyle.add_style provides an ML
  2780 interface for introducing further styles.  See also the "LaTeX Sugar"
  2781 document practical applications.  The ML antiquotation prints
  2782 type-checked ML expressions verbatim.
  2783 
  2784 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2785 and 'text' support optional locale specification '(in loc)', which
  2786 specifies the default context for interpreting antiquotations.  For
  2787 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2788 
  2789 * Option 'locale=NAME' of antiquotations specifies an alternative
  2790 context interpreting the subsequent argument.  For example: @{thm
  2791 [locale=lattice] inf_assoc}.
  2792 
  2793 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2794 a proof context.
  2795 
  2796 * Proper output of antiquotations for theory commands involving a
  2797 proof context (such as 'locale' or 'theorem (in loc) ...').
  2798 
  2799 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2800 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2801 
  2802 * isatool usedir: new option -C (default true) controls whether option
  2803 -D should include a copy of the original document directory; -C false
  2804 prevents unwanted effects such as copying of administrative CVS data.
  2805 
  2806 
  2807 *** Pure ***
  2808 
  2809 * Considerably improved version of 'constdefs' command.  Now performs
  2810 automatic type-inference of declared constants; additional support for
  2811 local structure declarations (cf. locales and HOL records), see also
  2812 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2813 sequential dependencies of definitions within a single 'constdefs'
  2814 section; moreover, the declared name needs to be an identifier.  If
  2815 all fails, consider to fall back on 'consts' and 'defs' separately.
  2816 
  2817 * Improved indexed syntax and implicit structures.  First of all,
  2818 indexed syntax provides a notational device for subscripted
  2819 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2820 expressions.  Secondly, in a local context with structure
  2821 declarations, number indexes \<^sub>n or the empty index (default
  2822 number 1) refer to a certain fixed variable implicitly; option
  2823 show_structs controls printing of implicit structures.  Typical
  2824 applications of these concepts involve record types and locales.
  2825 
  2826 * New command 'no_syntax' removes grammar declarations (and
  2827 translations) resulting from the given syntax specification, which is
  2828 interpreted in the same manner as for the 'syntax' command.
  2829 
  2830 * 'Advanced' translation functions (parse_translation etc.) may depend
  2831 on the signature of the theory context being presently used for
  2832 parsing/printing, see also isar-ref manual.
  2833 
  2834 * Improved 'oracle' command provides a type-safe interface to turn an
  2835 ML expression of type theory -> T -> term into a primitive rule of
  2836 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2837 is already included here); see also FOL/ex/IffExample.thy;
  2838 INCOMPATIBILITY.
  2839 
  2840 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2841 before); "cI" is no longer bound, use "c.intro" instead.
  2842 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2843 axclasses vs. locales.
  2844 
  2845 * Improved internal renaming of symbolic identifiers -- attach primes
  2846 instead of base 26 numbers.
  2847 
  2848 * New flag show_question_marks controls printing of leading question
  2849 marks in schematic variable names.
  2850 
  2851 * In schematic variable names, *any* symbol following \<^isub> or
  2852 \<^isup> is now treated as part of the base name.  For example, the
  2853 following works without printing of awkward ".0" indexes:
  2854 
  2855   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2856     by simp
  2857 
  2858 * Inner syntax includes (*(*nested*) comments*).
  2859 
  2860 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2861 annotations as "(00...)".
  2862 
  2863 * Clear separation of logical types and nonterminals, where the latter
  2864 may only occur in 'syntax' specifications or type abbreviations.
  2865 Before that distinction was only partially implemented via type class
  2866 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2867 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2868 exotic syntax specifications may require further adaption
  2869 (e.g. Cube/Cube.thy).
  2870 
  2871 * Removed obsolete type class "logic", use the top sort {} instead.
  2872 Note that non-logical types should be declared as 'nonterminals'
  2873 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2874 specifications.
  2875 
  2876 * Attributes 'induct' and 'cases': type or set names may now be
  2877 locally fixed variables as well.
  2878 
  2879 * Simplifier: can now control the depth to which conditional rewriting
  2880 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2881 Limit.
  2882 
  2883 * Simplifier: simplification procedures may now take the current
  2884 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2885 interface), which is very useful for calling the Simplifier
  2886 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2887 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2888 low-level mk_simproc no longer applies Logic.varify internally, to
  2889 allow for use in a context of fixed variables.
  2890 
  2891 * thin_tac now works even if the assumption being deleted contains !!
  2892 or ==>.  More generally, erule now works even if the major premise of
  2893 the elimination rule contains !! or ==>.
  2894 
  2895 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2896 
  2897 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2898 from Pure, which contains all common declarations already.  Both
  2899 theories are defined via plain Isabelle/Isar .thy files.
  2900 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2901 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2902 use isatool fixcpure to adapt your theory and ML sources.
  2903 
  2904 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2905 selections of theorems in named facts via index ranges.
  2906 
  2907 * 'print_theorems': in theory mode, really print the difference
  2908 wrt. the last state (works for interactive theory development only),
  2909 in proof mode print all local facts (cf. 'print_facts');
  2910 
  2911 * 'hide': option '(open)' hides only base names.
  2912 
  2913 * More efficient treatment of intermediate checkpoints in interactive
  2914 theory development.
  2915 
  2916 * Code generator is now invoked via code_module (incremental code
  2917 generation) and code_library (modular code generation, ML structures
  2918 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2919 must be quoted when used as identifiers.
  2920 
  2921 * New 'value' command for reading, evaluating and printing terms using
  2922 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2923 quoted when used as identifier.
  2924 
  2925 
  2926 *** Locales ***
  2927 
  2928 * New commands for the interpretation of locale expressions in
  2929 theories (1), locales (2) and proof contexts (3).  These generate
  2930 proof obligations from the expression specification.  After the
  2931 obligations have been discharged, theorems of the expression are added
  2932 to the theory, target locale or proof context.  The synopsis of the
  2933 commands is a follows:
  2934 
  2935   (1) interpretation expr inst
  2936   (2) interpretation target < expr
  2937   (3) interpret expr inst
  2938 
  2939 Interpretation in theories and proof contexts require a parameter
  2940 instantiation of terms from the current context.  This is applied to
  2941 specifications and theorems of the interpreted expression.
  2942 Interpretation in locales only permits parameter renaming through the
  2943 locale expression.  Interpretation is smart in that interpretations
  2944 that are active already do not occur in proof obligations, neither are
  2945 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2946 inspect active interpretations of a particular locale.  For details,
  2947 see the Isar Reference manual.  Examples can be found in
  2948 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2949 
  2950 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2951 'interpret' instead.
  2952 
  2953 * New context element 'constrains' for adding type constraints to
  2954 parameters.
  2955 
  2956 * Context expressions: renaming of parameters with syntax
  2957 redeclaration.
  2958 
  2959 * Locale declaration: 'includes' disallowed.
  2960 
  2961 * Proper static binding of attribute syntax -- i.e. types / terms /
  2962 facts mentioned as arguments are always those of the locale definition
  2963 context, independently of the context of later invocations.  Moreover,
  2964 locale operations (renaming and type / term instantiation) are applied
  2965 to attribute arguments as expected.
  2966 
  2967 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2968 actual attributes; rare situations may require Attrib.attribute to
  2969 embed those attributes into Attrib.src that lack concrete syntax.
  2970 Attribute implementations need to cooperate properly with the static
  2971 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2972 Attrib.XXX_thm etc. already do the right thing without further
  2973 intervention.  Only unusual applications -- such as "where" or "of"
  2974 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2975 on the context and the facts involved -- may have to assign parsed
  2976 values to argument tokens explicitly.
  2977 
  2978 * Changed parameter management in theorem generation for long goal
  2979 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2980 theorem statement in rare situations.
  2981 
  2982 * Locale inspection command 'print_locale' omits notes elements.  Use
  2983 'print_locale!' to have them included in the output.
  2984 
  2985 
  2986 *** Provers ***
  2987 
  2988 * Provers/hypsubst.ML: improved version of the subst method, for
  2989 single-step rewriting: it now works in bound variable contexts. New is
  2990 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2991 rewrite a different subterm than the original subst method, which is
  2992 still available as 'simplesubst'.
  2993 
  2994 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2995 and quasi orders.
  2996 
  2997 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2998 reflexive-transitive closure of relations.
  2999 
  3000 * Provers/blast.ML: new reference depth_limit to make blast's depth
  3001 limit (previously hard-coded with a value of 20) user-definable.
  3002 
  3003 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  3004 is peformed already.  Object-logics merely need to finish their
  3005 initial simpset configuration as before.  INCOMPATIBILITY.
  3006 
  3007 
  3008 *** HOL ***
  3009 
  3010 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3011 
  3012   syntax (epsilon)
  3013     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3014 
  3015 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3016 and x-symbol; use option '-m epsilon' to get it actually printed.
  3017 Moreover, the mathematically important symbolic identifier \<epsilon>
  3018 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3019 
  3020 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3021 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3022 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3023 support corresponding Isar calculations.
  3024 
  3025 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3026 instead of ":".
  3027 
  3028 * theory SetInterval: changed the syntax for open intervals:
  3029 
  3030   Old       New
  3031   {..n(}    {..<n}
  3032   {)n..}    {n<..}
  3033   {m..n(}   {m..<n}
  3034   {)m..n}   {m<..n}
  3035   {)m..n(}  {m<..<n}
  3036 
  3037 The old syntax is still supported but will disappear in the next
  3038 release.  For conversion use the following Emacs search and replace
  3039 patterns (these are not perfect but work quite well):
  3040 
  3041   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3042   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3043 
  3044 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3045 equalities in commutative rings; method 'algebra' provides a generic
  3046 interface.
  3047 
  3048 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3049 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3050 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3051 be a tuple pattern.
  3052 
  3053 Some new syntax forms are available:
  3054 
  3055   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3056   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3057   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3058   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3059 
  3060 The latter form "\<Sum>x < k. e" used to be based on a separate
  3061 function "Summation", which has been discontinued.
  3062 
  3063 * theory Finite_Set: in structured induction proofs, the insert case
  3064 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3065 (insert F x)'.
  3066 
  3067 * The 'refute' command has been extended to support a much larger
  3068 fragment of HOL, including axiomatic type classes, constdefs and
  3069 typedefs, inductive datatypes and recursion.
  3070 
  3071 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3072 Requires zChaff with proof generation to be installed.  See
  3073 HOL/ex/SAT_Examples.thy for examples.
  3074 
  3075 * Datatype induction via method 'induct' now preserves the name of the
  3076 induction variable. For example, when proving P(xs::'a list) by
  3077 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3078 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3079 in unstructured proof scripts.
  3080 
  3081 * Reworked implementation of records.  Improved scalability for
  3082 records with many fields, avoiding performance problems for type
  3083 inference. Records are no longer composed of nested field types, but
  3084 of nested extension types. Therefore the record type only grows linear
  3085 in the number of extensions and not in the number of fields.  The
  3086 top-level (users) view on records is preserved.  Potential
  3087 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3088 old record representation. The type generated for a record is called
  3089 <record_name>_ext_type.
  3090 
  3091 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3092 proofs triggered by a record definition or a simproc (if
  3093 quick_and_dirty is enabled).  Definitions of large records can take
  3094 quite long.
  3095 
  3096 New simproc record_upd_simproc for simplification of multiple record
  3097 updates enabled by default.  Moreover, trivial updates are also
  3098 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3099 occasionally, since simplification is more powerful by default.
  3100 
  3101 * typedef: proper support for polymorphic sets, which contain extra
  3102 type-variables in the term.
  3103 
  3104 * Simplifier: automatically reasons about transitivity chains
  3105 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3106 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3107 old proofs break occasionally as simplification may now solve more
  3108 goals than previously.
  3109 
  3110 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3111 present.  Works for all partial orders (class "order"), in particular
  3112 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3113 just like y <= x.
  3114 
  3115 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3116 bound variable or a constant then the let is unfolded.  Otherwise
  3117 first a is simplified to b, and then f b is simplified to g. If
  3118 possible we abstract b from g arriving at "let x = b in h x",
  3119 otherwise we unfold the let and arrive at g.  The simproc can be
  3120 enabled/disabled by the reference use_let_simproc.  Potential
  3121 INCOMPATIBILITY since simplification is more powerful by default.
  3122 
  3123 * Classical reasoning: the meson method now accepts theorems as arguments.
  3124 
  3125 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3126 jobs to provide advice on the provability of subgoals.
  3127 
  3128 * Theory OrderedGroup and Ring_and_Field: various additions and
  3129 improvements to faciliate calculations involving equalities and
  3130 inequalities.
  3131 
  3132 The following theorems have been eliminated or modified
  3133 (INCOMPATIBILITY):
  3134 
  3135   abs_eq             now named abs_of_nonneg
  3136   abs_of_ge_0        now named abs_of_nonneg
  3137   abs_minus_eq       now named abs_of_nonpos
  3138   imp_abs_id         now named abs_of_nonneg
  3139   imp_abs_neg_id     now named abs_of_nonpos
  3140   mult_pos           now named mult_pos_pos
  3141   mult_pos_le        now named mult_nonneg_nonneg
  3142   mult_pos_neg_le    now named mult_nonneg_nonpos
  3143   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3144   mult_neg           now named mult_neg_neg
  3145   mult_neg_le        now named mult_nonpos_nonpos
  3146 
  3147 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3148      
  3149      zero_le_square
  3150      not_square_less_zero 
  3151 
  3152   The following lemmas have been deleted from Real/RealPow:
  3153   
  3154      realpow_zero_zero
  3155      realpow_two
  3156      realpow_less
  3157      zero_le_power
  3158      realpow_two_le
  3159      abs_realpow_two
  3160      realpow_two_abs     
  3161 
  3162 * Theory Parity: added rules for simplifying exponents.
  3163 
  3164 * Theory List:
  3165 
  3166 The following theorems have been eliminated or modified
  3167 (INCOMPATIBILITY):
  3168 
  3169   list_all_Nil       now named list_all.simps(1)
  3170   list_all_Cons      now named list_all.simps(2)
  3171   list_all_conv      now named list_all_iff
  3172   set_mem_eq         now named mem_iff
  3173 
  3174 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3175 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3176 
  3177 
  3178 *** HOL-Complex ***
  3179 
  3180 * Theory RealDef: better support for embedding natural numbers and
  3181 integers in the reals.
  3182 
  3183 The following theorems have been eliminated or modified
  3184 (INCOMPATIBILITY):
  3185 
  3186   exp_ge_add_one_self  now requires no hypotheses
  3187   real_of_int_add      reversed direction of equality (use [symmetric])
  3188   real_of_int_minus    reversed direction of equality (use [symmetric])
  3189   real_of_int_diff     reversed direction of equality (use [symmetric])
  3190   real_of_int_mult     reversed direction of equality (use [symmetric])
  3191 
  3192 * Theory RComplete: expanded support for floor and ceiling functions.
  3193 
  3194 * Theory Ln is new, with properties of the natural logarithm
  3195 
  3196 * Hyperreal: There is a new type constructor "star" for making
  3197 nonstandard types.  The old type names are now type synonyms:
  3198 
  3199   hypreal = real star
  3200   hypnat = nat star
  3201   hcomplex = complex star
  3202 
  3203 * Hyperreal: Many groups of similarly-defined constants have been
  3204 replaced by polymorphic versions (INCOMPATIBILITY):
  3205 
  3206   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3207 
  3208   starset      <-- starsetNat, starsetC
  3209   *s*          <-- *sNat*, *sc*
  3210   starset_n    <-- starsetNat_n, starsetC_n
  3211   *sn*         <-- *sNatn*, *scn*
  3212   InternalSets <-- InternalNatSets, InternalCSets
  3213 
  3214   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3215   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3216   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3217   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3218   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3219 
  3220 * Hyperreal: Many type-specific theorems have been removed in favor of
  3221 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3222 
  3223   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3224   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3225   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3226   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3227   right_minus <-- hypreal_add_minus
  3228   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3229   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3230   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3231   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3232   mult_1_right <-- hcomplex_mult_one_right
  3233   mult_zero_left <-- hcomplex_mult_zero_left
  3234   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3235   right_distrib <-- hypnat_add_mult_distrib2
  3236   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3237   right_inverse <-- hypreal_mult_inverse
  3238   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3239   order_refl <-- {hypreal,hypnat}_le_refl
  3240   order_trans <-- {hypreal,hypnat}_le_trans
  3241   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3242   order_less_le <-- {hypreal,hypnat}_less_le
  3243   linorder_linear <-- {hypreal,hypnat}_le_linear
  3244   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3245   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3246   add_nonneg_nonneg <-- hypreal_le_add_order
  3247 
  3248 * Hyperreal: Separate theorems having to do with type-specific
  3249 versions of constants have been merged into theorems that apply to the
  3250 new polymorphic constants (INCOMPATIBILITY):
  3251 
  3252   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3253   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3254   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3255   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3256   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3257   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3258   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3259   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3260   STAR_diff <-- {STAR,STARC}_diff
  3261   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3262     STARC_hcomplex_of_complex}_image_subset
  3263   starset_n_Un <-- starset{Nat,C}_n_Un
  3264   starset_n_Int <-- starset{Nat,C}_n_Int
  3265   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3266   starset_n_diff <-- starset{Nat,C}_n_diff
  3267   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3268   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3269   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3270   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3271   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3272   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3273   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3274   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3275   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3276   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3277   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3278   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3279   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3280   starfun_diff <-- starfun{C,RC,CR}_diff
  3281   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3282   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3283   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3284   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3285   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3286   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3287   starfun_Id <-- starfunC_Id
  3288   starfun_approx <-- starfun{Nat,CR}_approx
  3289   starfun_capprox <-- starfun{C,RC}_capprox
  3290   starfun_abs <-- starfunNat_rabs
  3291   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3292   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3293   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3294   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3295   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3296   starfun_add_approx <-- starfunCR_add_approx
  3297   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3298   starfun_divide <-- starfun{C,CR,RC}_divide
  3299   starfun_n <-- starfun{Nat,C}_n
  3300   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3301   starfun_n_add <-- starfun{Nat,C}_n_add
  3302   starfun_n_add_minus <-- starfunNat_n_add_minus
  3303   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3304   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3305   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3306 
  3307   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3308   star_n_minus <-- {hypreal,hcomplex}_minus
  3309   star_n_diff <-- {hypreal,hcomplex}_diff
  3310   star_n_mult <-- {hypreal,hcomplex}_mult
  3311   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3312   star_n_le <-- {hypreal,hypnat}_le
  3313   star_n_less <-- {hypreal,hypnat}_less
  3314   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3315   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3316   star_n_abs <-- hypreal_hrabs
  3317   star_n_divide <-- hcomplex_divide
  3318 
  3319   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3320   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3321   star_of_diff <-- hypreal_of_real_diff
  3322   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3323   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3324   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3325   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3326   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3327   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3328   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3329   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3330   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3331   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3332   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3333   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3334   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3335   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3336   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3337   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3338   star_of_power <-- hypreal_of_real_power
  3339   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3340 
  3341 * Hyperreal: new method "transfer" that implements the transfer
  3342 principle of nonstandard analysis. With a subgoal that mentions
  3343 nonstandard types like "'a star", the command "apply transfer"
  3344 replaces it with an equivalent one that mentions only standard types.
  3345 To be successful, all free variables must have standard types; non-
  3346 standard variables must have explicit universal quantifiers.
  3347 
  3348 * Hyperreal: A theory of Taylor series.
  3349 
  3350 
  3351 *** HOLCF ***
  3352 
  3353 * Discontinued special version of 'constdefs' (which used to support
  3354 continuous functions) in favor of the general Pure one with full
  3355 type-inference.
  3356 
  3357 * New simplification procedure for solving continuity conditions; it
  3358 is much faster on terms with many nested lambda abstractions (cubic
  3359 instead of exponential time).
  3360 
  3361 * New syntax for domain package: selector names are now optional.
  3362 Parentheses should be omitted unless argument is lazy, for example:
  3363 
  3364   domain 'a stream = cons "'a" (lazy "'a stream")
  3365 
  3366 * New command 'fixrec' for defining recursive functions with pattern
  3367 matching; defining multiple functions with mutual recursion is also
  3368 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3369 sinr, or any data constructor defined by the domain package. The given
  3370 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3371 syntax and examples.
  3372 
  3373 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3374 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3375 but the proof obligation additionally includes an admissibility
  3376 requirement. The packages generate instances of class cpo or pcpo,
  3377 with continuity and strictness theorems for Rep and Abs.
  3378 
  3379 * HOLCF: Many theorems have been renamed according to a more standard naming
  3380 scheme (INCOMPATIBILITY):
  3381 
  3382   foo_inject:  "foo$x = foo$y ==> x = y"
  3383   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3384   foo_less:    "(foo$x << foo$y) = (x << y)"
  3385   foo_strict:  "foo$UU = UU"
  3386   foo_defined: "... ==> foo$x ~= UU"
  3387   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3388 
  3389 
  3390 *** ZF ***
  3391 
  3392 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3393 including the First Isomorphism Theorem (on quotienting by the kernel
  3394 of a homomorphism).
  3395 
  3396 * ZF/Simplifier: install second copy of type solver that actually
  3397 makes use of TC rules declared to Isar proof contexts (or locales);
  3398 the old version is still required for ML proof scripts.
  3399 
  3400 
  3401 *** Cube ***
  3402 
  3403 * Converted to Isar theory format; use locales instead of axiomatic
  3404 theories.
  3405 
  3406 
  3407 *** ML ***
  3408 
  3409 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3410 for ||>, ||>>, |>>,
  3411 
  3412 * Pure/library.ML no longer defines its own option datatype, but uses
  3413 that of the SML basis, which has constructors NONE and SOME instead of
  3414 None and Some, as well as exception Option.Option instead of OPTION.
  3415 The functions the, if_none, is_some, is_none have been adapted
  3416 accordingly, while Option.map replaces apsome.
  3417 
  3418 * Pure/library.ML: the exception LIST has been given up in favour of
  3419 the standard exceptions Empty and Subscript, as well as
  3420 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3421 superceded by the standard hd and tl functions etc.
  3422 
  3423 A number of basic list functions are no longer exported to the ML
  3424 toplevel, as they are variants of predefined functions.  The following
  3425 suggests how one can translate existing code:
  3426 
  3427     rev_append xs ys = List.revAppend (xs, ys)
  3428     nth_elem (i, xs) = List.nth (xs, i)
  3429     last_elem xs = List.last xs
  3430     flat xss = List.concat xss
  3431     seq fs = List.app fs
  3432     partition P xs = List.partition P xs
  3433     mapfilter f xs = List.mapPartial f xs
  3434 
  3435 * Pure/library.ML: several combinators for linear functional
  3436 transformations, notably reverse application and composition:
  3437 
  3438   x |> f                f #> g
  3439   (x, y) |-> f          f #-> g
  3440 
  3441 * Pure/library.ML: introduced/changed precedence of infix operators:
  3442 
  3443   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3444   infix 2 ?;
  3445   infix 3 o oo ooo oooo;
  3446   infix 4 ~~ upto downto;
  3447 
  3448 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3449 infix operators.
  3450 
  3451 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3452 fold_map support linear functional transformations and nesting.  For
  3453 example:
  3454 
  3455   fold f [x1, ..., xN] y =
  3456     y |> f x1 |> ... |> f xN
  3457 
  3458   (fold o fold) f [xs1, ..., xsN] y =
  3459     y |> fold f xs1 |> ... |> fold f xsN
  3460 
  3461   fold f [x1, ..., xN] =
  3462     f x1 #> ... #> f xN
  3463 
  3464   (fold o fold) f [xs1, ..., xsN] =
  3465     fold f xs1 #> ... #> fold f xsN
  3466 
  3467 * Pure/library.ML: the following selectors on type 'a option are
  3468 available:
  3469 
  3470   the:               'a option -> 'a  (*partial*)
  3471   these:             'a option -> 'a  where 'a = 'b list
  3472   the_default: 'a -> 'a option -> 'a
  3473   the_list:          'a option -> 'a list
  3474 
  3475 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3476 basic operations for association lists, following natural argument
  3477 order; moreover the explicit equality predicate passed here avoids
  3478 potentially expensive polymorphic runtime equality checks.
  3479 The old functions may be expressed as follows:
  3480 
  3481   assoc = uncurry (AList.lookup (op =))
  3482   assocs = these oo AList.lookup (op =)
  3483   overwrite = uncurry (AList.update (op =)) o swap
  3484 
  3485 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3486 
  3487   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3488   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3489 
  3490 replacing make_keylist and keyfilter (occassionally used)
  3491 Naive rewrites:
  3492 
  3493   make_keylist = AList.make
  3494   keyfilter = AList.find (op =)
  3495 
  3496 * eq_fst and eq_snd now take explicit equality parameter, thus
  3497   avoiding eqtypes. Naive rewrites:
  3498 
  3499     eq_fst = eq_fst (op =)
  3500     eq_snd = eq_snd (op =)
  3501 
  3502 * Removed deprecated apl and apr (rarely used).
  3503   Naive rewrites:
  3504 
  3505     apl (n, op) =>>= curry op n
  3506     apr (op, m) =>>= fn n => op (n, m)
  3507 
  3508 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3509 provides a reasonably efficient light-weight implementation of sets as
  3510 lists.
  3511 
  3512 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3513 few new operations; existing lookup and update are now curried to
  3514 follow natural argument order (for use with fold etc.);
  3515 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3516 
  3517 * Pure/General: output via the Isabelle channels of
  3518 writeln/warning/error etc. is now passed through Output.output, with a
  3519 hook for arbitrary transformations depending on the print_mode
  3520 (cf. Output.add_mode -- the first active mode that provides a output
  3521 function wins).  Already formatted output may be embedded into further
  3522 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3523 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3524 accommodate easy composition of diagnostic messages etc.  Programmers
  3525 rarely need to care about Output.output or Output.raw at all, with
  3526 some notable exceptions: Output.output is required when bypassing the
  3527 standard channels (writeln etc.), or in token translations to produce
  3528 properly formatted results; Output.raw is required when capturing
  3529 already output material that will eventually be presented to the user
  3530 a second time.  For the default print mode, both Output.output and
  3531 Output.raw have no effect.
  3532 
  3533 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3534 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3535 cumulative results are displayed at the end of a batch session.
  3536 
  3537 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3538 replaced by File.platform_path and File.shell_path (with appropriate
  3539 hooks).  This provides a clean interface for unusual systems where the
  3540 internal and external process view of file names are different.
  3541 
  3542 * Pure: more efficient orders for basic syntactic entities: added
  3543 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3544 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3545 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3546 orders now -- potential INCOMPATIBILITY for code that depends on a
  3547 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3548 Library.sort_strings on result).
  3549 
  3550 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3551 fold_types traverse types/terms from left to right, observing natural
  3552 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3553 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3554 
  3555 * Pure: name spaces have been refined, with significant changes of the
  3556 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3557 to extern(_table).  The plain name entry path is superceded by a
  3558 general 'naming' context, which also includes the 'policy' to produce
  3559 a fully qualified name and external accesses of a fully qualified
  3560 name; NameSpace.extend is superceded by context dependent
  3561 Sign.declare_name.  Several theory and proof context operations modify
  3562 the naming context.  Especially note Theory.restore_naming and
  3563 ProofContext.restore_naming to get back to a sane state; note that
  3564 Theory.add_path is no longer sufficient to recover from
  3565 Theory.absolute_path in particular.
  3566 
  3567 * Pure: new flags short_names (default false) and unique_names
  3568 (default true) for controlling output of qualified names.  If
  3569 short_names is set, names are printed unqualified.  If unique_names is
  3570 reset, the name prefix is reduced to the minimum required to achieve
  3571 the original result when interning again, even if there is an overlap
  3572 with earlier declarations.
  3573 
  3574 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3575 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3576 (useful for printing error messages).  INCOMPATIBILITY.
  3577 
  3578 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3579 Theory.theory are now identified, referring to the universal
  3580 Context.theory (see Pure/context.ML).  Actual signature and theory
  3581 content is managed as theory data.  The old code and interfaces were
  3582 spread over many files and structures; the new arrangement introduces
  3583 considerable INCOMPATIBILITY to gain more clarity:
  3584 
  3585   Context -- theory management operations (name, identity, inclusion,
  3586     parents, ancestors, merge, etc.), plus generic theory data;
  3587 
  3588   Sign -- logical signature and syntax operations (declaring consts,
  3589     types, etc.), plus certify/read for common entities;
  3590 
  3591   Theory -- logical theory operations (stating axioms, definitions,
  3592     oracles), plus a copy of logical signature operations (consts,
  3593     types, etc.); also a few basic management operations (Theory.copy,
  3594     Theory.merge, etc.)
  3595 
  3596 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3597 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3598 for convenience -- they merely return the theory.
  3599 
  3600 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3601 
  3602 * Pure: the Isar proof context type is already defined early in Pure
  3603 as Context.proof (note that ProofContext.context and Proof.context are
  3604 aliases, where the latter is the preferred name).  This enables other
  3605 Isabelle components to refer to that type even before Isar is present.
  3606 
  3607 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3608 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3609 any of these kinds.  For example, Sign.intern typeK is now
  3610 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3611 Theory.hide_types.  Also note that former
  3612 Theory.hide_classes/types/consts are now
  3613 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3614 internalize their arguments!  INCOMPATIBILITY.
  3615 
  3616 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3617 datatype thmref (with constructors Name and NameSelection) instead of
  3618 plain string -- INCOMPATIBILITY;
  3619 
  3620 * Pure: cases produced by proof methods specify options, where NONE
  3621 means to remove case bindings -- INCOMPATIBILITY in
  3622 (RAW_)METHOD_CASES.
  3623 
  3624 * Pure: the following operations retrieve axioms or theorems from a
  3625 theory node or theory hierarchy, respectively:
  3626 
  3627   Theory.axioms_of: theory -> (string * term) list
  3628   Theory.all_axioms_of: theory -> (string * term) list
  3629   PureThy.thms_of: theory -> (string * thm) list
  3630   PureThy.all_thms_of: theory -> (string * thm) list
  3631 
  3632 * Pure: print_tac now outputs the goal through the trace channel.
  3633 
  3634 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3635 Reference Toplevel.debug (default false) controls detailed printing
  3636 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3637 controls execution profiling -- set to 1 for time and 2 for space
  3638 (both increase the runtime).
  3639 
  3640 * Isar session: The initial use of ROOT.ML is now always timed,
  3641 i.e. the log will show the actual process times, in contrast to the
  3642 elapsed wall-clock time that the outer shell wrapper produces.
  3643 
  3644 * Simplifier: improved handling of bound variables (nameless
  3645 representation, avoid allocating new strings).  Simprocs that invoke
  3646 the Simplifier recursively should use Simplifier.inherit_bounds to
  3647 avoid local name clashes.  Failure to do so produces warnings
  3648 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3649 for further details.
  3650 
  3651 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3652 bindings for all theorems stored within a given theory; this may help
  3653 in porting non-Isar theories to Isar ones, while keeping ML proof
  3654 scripts for the time being.
  3655 
  3656 * ML operator HTML.with_charset specifies the charset begin used for
  3657 generated HTML files.  For example:
  3658 
  3659   HTML.with_charset "utf-8" use_thy "Hebrew";
  3660   HTML.with_charset "utf-8" use_thy "Chinese";
  3661 
  3662 
  3663 *** System ***
  3664 
  3665 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3666 isabelle, isatool etc.).
  3667 
  3668 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3669 isatool doc, isatool mkdir, display_drafts etc.).
  3670 
  3671 * isatool usedir: option -f allows specification of the ML file to be
  3672 used by Isabelle; default is ROOT.ML.
  3673 
  3674 * New isatool version outputs the version identifier of the Isabelle
  3675 distribution being used.
  3676 
  3677 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3678 (containing Boolean satisfiability problems) into Isabelle/HOL
  3679 theories.
  3680 
  3681 
  3682 
  3683 New in Isabelle2004 (April 2004)
  3684 --------------------------------
  3685 
  3686 *** General ***
  3687 
  3688 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3689   Replaces linorder.ML.
  3690 
  3691 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3692   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3693   (\<a>...\<z>), are now considered normal letters, and can therefore
  3694   be used anywhere where an ASCII letter (a...zA...Z) has until
  3695   now. COMPATIBILITY: This obviously changes the parsing of some
  3696   terms, especially where a symbol has been used as a binder, say
  3697   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3698   as an identifier.  Fix it by inserting a space around former
  3699   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3700   existing theory and ML files.
  3701 
  3702 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3703 
  3704 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3705   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3706   a normal (but invisible) letter. For multiple letter subscripts repeat
  3707   \<^isub> like this: x\<^isub>1\<^isub>2.
  3708 
  3709 * Pure: There are now sub-/superscripts that can span more than one
  3710   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3711   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3712   superscript. The new control characters are not identifier parts.
  3713 
  3714 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3715   content of "..." to the latex file instead of \isacntrl... . The "..."
  3716   may consist of any printable characters excluding the end bracket >.
  3717 
  3718 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3719   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3720   declare constants "final", which prevents their being given a definition
  3721   later.  It is useful for constants whose behaviour is fixed axiomatically
  3722   rather than definitionally, such as the meta-logic connectives.
  3723 
  3724 * Pure: 'instance' now handles general arities with general sorts
  3725   (i.e. intersections of classes),
  3726 
  3727 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3728   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3729   It can be changed to alter the colors/layout of generated pages.
  3730 
  3731 
  3732 *** Isar ***
  3733 
  3734 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3735   cut_tac, subgoal_tac and thin_tac:
  3736   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3737     locales are no longer forced to write Isar proof scripts.
  3738     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3739     emulations.
  3740   - INCOMPATIBILITY: names of variables to be instantiated may no
  3741     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3742     This is consistent with the instantiation attribute "where".
  3743 
  3744 * Attributes "where" and "of":
  3745   - Now take type variables of instantiated theorem into account when reading
  3746     the instantiation string.  This fixes a bug that caused instantiated
  3747     theorems to have too special types in some circumstances.
  3748   - "where" permits explicit instantiations of type variables.
  3749 
  3750 * Calculation commands "moreover" and "also" no longer interfere with
  3751   current facts ("this"), admitting arbitrary combinations with "then"
  3752   and derived forms.
  3753 
  3754 * Locales:
  3755   - Goal statements involving the context element "includes" no longer
  3756     generate theorems with internal delta predicates (those ending on
  3757     "_axioms") in the premise.
  3758     Resolve particular premise with <locale>.intro to obtain old form.
  3759   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3760     specification and "includes" elements in goal statement.
  3761   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3762     [intro?] and [elim?] (respectively) by default.
  3763   - Experimental command for instantiation of locales in proof contexts:
  3764         instantiate <label>[<attrs>]: <loc>
  3765     Instantiates locale <loc> and adds all its theorems to the current context
  3766     taking into account their attributes.  Label and attrs are optional
  3767     modifiers, like in theorem declarations.  If present, names of
  3768     instantiated theorems are qualified with <label>, and the attributes
  3769     <attrs> are applied after any attributes these theorems might have already.
  3770       If the locale has assumptions, a chained fact of the form
  3771     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3772     are derived.  The command does not support old-style locales declared
  3773     with "locale (open)".
  3774       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3775 
  3776 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3777   (Isar) contexts.
  3778 
  3779 
  3780 *** HOL ***
  3781 
  3782 * Proof import: new image HOL4 contains the imported library from
  3783   the HOL4 system with about 2500 theorems. It is imported by
  3784   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3785   can be used like any other Isabelle image.  See
  3786   HOL/Import/HOL/README for more information.
  3787 
  3788 * Simplifier:
  3789   - Much improved handling of linear and partial orders.
  3790     Reasoners for linear and partial orders are set up for type classes
  3791     "linorder" and "order" respectively, and are added to the default simpset
  3792     as solvers.  This means that the simplifier can build transitivity chains
  3793     to solve goals from the assumptions.
  3794   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3795     of blast or auto after simplification become unnecessary because the goal
  3796     is solved by simplification already.
  3797 
  3798 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3799     all proved in axiomatic type classes for semirings, rings and fields.
  3800 
  3801 * Numerics:
  3802   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3803     now formalized using the Ring_and_Field theory mentioned above.
  3804   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3805     than before, because now they are set up once in a generic manner.
  3806   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3807     Look for the general versions in Ring_and_Field (and Power if they concern
  3808     exponentiation).
  3809 
  3810 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3811 
  3812 * Records:
  3813   - Record types are now by default printed with their type abbreviation
  3814     instead of the list of all field types. This can be configured via
  3815     the reference "print_record_type_abbr".
  3816   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3817     (not enabled by default).
  3818   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3819     EX x. x = sel r to True (not enabled by default).
  3820   - Tactic "record_split_simp_tac" to split and simplify records added.
  3821 
  3822 * 'specification' command added, allowing for definition by
  3823   specification.  There is also an 'ax_specification' command that
  3824   introduces the new constants axiomatically.
  3825 
  3826 * arith(_tac) is now able to generate counterexamples for reals as well.
  3827 
  3828 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3829 
  3830 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3831   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3832 
  3833 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3834   matrix theory to linear programming.
  3835 
  3836 * Unions and Intersections:
  3837   The latex output syntax of UN and INT has been changed
  3838   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3839   i.e. the index formulae has become a subscript.
  3840   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3841 
  3842 * Unions and Intersections over Intervals:
  3843   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3844   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3845   like in normal math, and corresponding versions for < and for intersection.
  3846 
  3847 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3848   lexicographic dictonary ordering has been added as "lexord".
  3849 
  3850 * ML: the legacy theory structures Int and List have been removed. They had
  3851   conflicted with ML Basis Library structures having the same names.
  3852 
  3853 * 'refute' command added to search for (finite) countermodels.  Only works
  3854   for a fragment of HOL.  The installation of an external SAT solver is
  3855   highly recommended.  See "HOL/Refute.thy" for details.
  3856 
  3857 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3858   formulae under an assignment of free variables to random values.
  3859   In contrast to 'refute', it can deal with inductive datatypes,
  3860   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3861   for examples.
  3862 
  3863 
  3864 *** HOLCF ***
  3865 
  3866 * Streams now come with concatenation and are part of the HOLCF image
  3867 
  3868 
  3869 
  3870 New in Isabelle2003 (May 2003)
  3871 ------------------------------
  3872 
  3873 *** General ***
  3874 
  3875 * Provers/simplifier:
  3876 
  3877   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3878     Assumptions are now subject to complete mutual simplification,
  3879     not just from left to right. The simplifier now preserves
  3880     the order of assumptions.
  3881 
  3882     Potential INCOMPATIBILITY:
  3883 
  3884     -- simp sometimes diverges where the old version did
  3885        not, e.g. invoking simp on the goal
  3886 
  3887         [| P (f x); y = x; f x = f y |] ==> Q
  3888 
  3889        now gives rise to the infinite reduction sequence
  3890 
  3891         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3892 
  3893        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3894        kind of problem.
  3895 
  3896     -- Tactics combining classical reasoner and simplification (such as auto)
  3897        are also affected by this change, because many of them rely on
  3898        simp. They may sometimes diverge as well or yield a different numbers
  3899        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3900        in case of problems. Sometimes subsequent calls to the classical
  3901        reasoner will fail because a preceeding call to the simplifier too
  3902        eagerly simplified the goal, e.g. deleted redundant premises.
  3903 
  3904   - The simplifier trace now shows the names of the applied rewrite rules
  3905 
  3906   - You can limit the number of recursive invocations of the simplifier
  3907     during conditional rewriting (where the simplifie tries to solve the
  3908     conditions before applying the rewrite rule):
  3909     ML "simp_depth_limit := n"
  3910     where n is an integer. Thus you can force termination where previously
  3911     the simplifier would diverge.
  3912 
  3913   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3914 
  3915   - No longer aborts on failed congruence proof.  Instead, the
  3916     congruence is ignored.
  3917 
  3918 * Pure: New generic framework for extracting programs from constructive
  3919   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3920   as HOL/Extraction for some case studies.
  3921 
  3922 * Pure: The main goal of the proof state is no longer shown by default, only
  3923 the subgoals. This behaviour is controlled by a new flag.
  3924    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3925 (ML: Proof.show_main_goal).
  3926 
  3927 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3928 rules whose conclusion matches subgoal 1:
  3929       PG menu: Isabelle/Isar -> Show me -> matching rules
  3930 The rules are ordered by how closely they match the subgoal.
  3931 In particular, rules that solve a subgoal outright are displayed first
  3932 (or rather last, the way they are printed).
  3933 (ML: ProofGeneral.print_intros())
  3934 
  3935 * Pure: New flag trace_unify_fail causes unification to print
  3936 diagnostic information (PG: in trace buffer) when it fails. This is
  3937 useful for figuring out why single step proofs like rule, erule or
  3938 assumption failed.
  3939 
  3940 * Pure: Locale specifications now produce predicate definitions
  3941 according to the body of text (covering assumptions modulo local
  3942 definitions); predicate "loc_axioms" covers newly introduced text,
  3943 while "loc" is cumulative wrt. all included locale expressions; the
  3944 latter view is presented only on export into the global theory
  3945 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3946 on the old view without predicates;
  3947 
  3948 * Pure: predefined locales "var" and "struct" are useful for sharing
  3949 parameters (as in CASL, for example); just specify something like
  3950 ``var x + var y + struct M'' as import;
  3951 
  3952 * Pure: improved thms_containing: proper indexing of facts instead of
  3953 raw theorems; check validity of results wrt. current name space;
  3954 include local facts of proof configuration (also covers active
  3955 locales), cover fixed variables in index; may use "_" in term
  3956 specification; an optional limit for the number of printed facts may
  3957 be given (the default is 40);
  3958 
  3959 * Pure: disallow duplicate fact bindings within new-style theory files
  3960 (batch-mode only);
  3961 
  3962 * Provers: improved induct method: assumptions introduced by case
  3963 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3964 the goal statement); "foo" still refers to all facts collectively;
  3965 
  3966 * Provers: the function blast.overloaded has been removed: all constants
  3967 are regarded as potentially overloaded, which improves robustness in exchange
  3968 for slight decrease in efficiency;
  3969 
  3970 * Provers/linorder: New generic prover for transitivity reasoning over
  3971 linear orders.  Note: this prover is not efficient!
  3972 
  3973 * Isar: preview of problems to finish 'show' now produce an error
  3974 rather than just a warning (in interactive mode);
  3975 
  3976 
  3977 *** HOL ***
  3978 
  3979 * arith(_tac)
  3980 
  3981  - Produces a counter example if it cannot prove a goal.
  3982    Note that the counter example may be spurious if the goal is not a formula
  3983    of quantifier-free linear arithmetic.
  3984    In ProofGeneral the counter example appears in the trace buffer.
  3985 
  3986  - Knows about div k and mod k where k is a numeral of type nat or int.
  3987 
  3988  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3989    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3990    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3991 
  3992 * simp's arithmetic capabilities have been enhanced a bit: it now
  3993 takes ~= in premises into account (by performing a case split);
  3994 
  3995 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3996 are distributed over a sum of terms;
  3997 
  3998 * New tactic "trans_tac" and method "trans" instantiate
  3999 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  4000 "<=", "<" and "=").
  4001 
  4002 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  4003 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  4004 
  4005 * 'typedef' command has new option "open" to suppress the set
  4006 definition;
  4007 
  4008 * functions Min and Max on finite sets have been introduced (theory
  4009 Finite_Set);
  4010 
  4011 * attribute [symmetric] now works for relations as well; it turns
  4012 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4013 
  4014 * induct over a !!-quantified statement (say !!x1..xn):
  4015   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4016 
  4017 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4018 %x. None. Warning: empty_def now refers to the previously hidden definition
  4019 of the empty set.
  4020 
  4021 * Algebra: formalization of classical algebra.  Intended as base for
  4022 any algebraic development in Isabelle.  Currently covers group theory
  4023 (up to Sylow's theorem) and ring theory (Universal Property of
  4024 Univariate Polynomials).  Contributions welcome;
  4025 
  4026 * GroupTheory: deleted, since its material has been moved to Algebra;
  4027 
  4028 * Complex: new directory of the complex numbers with numeric constants,
  4029 nonstandard complex numbers, and some complex analysis, standard and
  4030 nonstandard (Jacques Fleuriot);
  4031 
  4032 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4033 
  4034 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4035 Fleuriot);
  4036 
  4037 * Real/HahnBanach: updated and adapted to locales;
  4038 
  4039 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4040 Gray and Kramer);
  4041 
  4042 * UNITY: added the Meier-Sanders theory of progress sets;
  4043 
  4044 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4045 as abstract algorithms, instantiated to the JVM;
  4046 
  4047 * Bali: Java source language formalization. Type system, operational
  4048 semantics, axiomatic semantics. Supported language features:
  4049 classes, interfaces, objects,virtual methods, static methods,
  4050 static/instance fields, arrays, access modifiers, definite
  4051 assignment, exceptions.
  4052 
  4053 
  4054 *** ZF ***
  4055 
  4056 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4057 universe, etc.);
  4058 
  4059 * Main ZF: virtually all theories converted to new-style format;
  4060 
  4061 
  4062 *** ML ***
  4063 
  4064 * Pure: Tactic.prove provides sane interface for internal proofs;
  4065 omits the infamous "standard" operation, so this is more appropriate
  4066 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4067 
  4068 * Pure: improved error reporting of simprocs;
  4069 
  4070 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4071 up simprocs;
  4072 
  4073 
  4074 *** Document preparation ***
  4075 
  4076 * uses \par instead of \\ for line breaks in theory text. This may
  4077 shift some page breaks in large documents. To get the old behaviour
  4078 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4079 
  4080 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4081 other packages
  4082 
  4083 * \<euro> now needs package babel/greek instead of marvosym (which
  4084 broke \Rightarrow)
  4085 
  4086 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4087 textcomp package)
  4088 
  4089 
  4090 
  4091 New in Isabelle2002 (March 2002)
  4092 --------------------------------
  4093 
  4094 *** Document preparation ***
  4095 
  4096 * greatly simplified document preparation setup, including more
  4097 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4098 instructive isatool mkdir; users should basically be able to get
  4099 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4100 users may run a separate document processing stage manually like this:
  4101 "isatool usedir -D output HOL Test && isatool document Test/output";
  4102 
  4103 * theory dependency graph may now be incorporated into documents;
  4104 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4105 with \includegraphics of LaTeX;
  4106 
  4107 * proper spacing of consecutive markup elements, especially text
  4108 blocks after section headings;
  4109 
  4110 * support bold style (for single symbols only), input syntax is like
  4111 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4112 
  4113 * \<bullet> is now output as bold \cdot by default, which looks much
  4114 better in printed text;
  4115 
  4116 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4117 note that these symbols are currently unavailable in Proof General /
  4118 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4119 
  4120 * isatool latex no longer depends on changed TEXINPUTS, instead
  4121 isatool document copies the Isabelle style files to the target
  4122 location;
  4123 
  4124 
  4125 *** Isar ***
  4126 
  4127 * Pure/Provers: improved proof by cases and induction;
  4128   - 'case' command admits impromptu naming of parameters (such as
  4129     "case (Suc n)");
  4130   - 'induct' method divinates rule instantiation from the inductive
  4131     claim; no longer requires excessive ?P bindings for proper
  4132     instantiation of cases;
  4133   - 'induct' method properly enumerates all possibilities of set/type
  4134     rules; as a consequence facts may be also passed through *type*
  4135     rules without further ado;
  4136   - 'induct' method now derives symbolic cases from the *rulified*
  4137     rule (before it used to rulify cases stemming from the internal
  4138     atomized version); this means that the context of a non-atomic
  4139     statement becomes is included in the hypothesis, avoiding the
  4140     slightly cumbersome show "PROP ?case" form;
  4141   - 'induct' may now use elim-style induction rules without chaining
  4142     facts, using ``missing'' premises from the goal state; this allows
  4143     rules stemming from inductive sets to be applied in unstructured
  4144     scripts, while still benefitting from proper handling of non-atomic
  4145     statements; NB: major inductive premises need to be put first, all
  4146     the rest of the goal is passed through the induction;
  4147   - 'induct' proper support for mutual induction involving non-atomic
  4148     rule statements (uses the new concept of simultaneous goals, see
  4149     below);
  4150   - append all possible rule selections, but only use the first
  4151     success (no backtracking);
  4152   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4153   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4154   - added 'print_induct_rules' (covered by help item in recent Proof
  4155     General versions);
  4156   - moved induct/cases attributes to Pure, methods to Provers;
  4157   - generic method setup instantiated for FOL and HOL;
  4158 
  4159 * Pure: support multiple simultaneous goal statements, for example
  4160 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4161 meta-level mechanism, this acts as if several individual goals had
  4162 been stated separately; in particular common proof methods need to be
  4163 repeated in order to cover all claims; note that a single elimination
  4164 step is *not* sufficient to establish the two conjunctions, so this
  4165 fails:
  4166 
  4167   assume "A & B" then have A and B ..   (*".." fails*)
  4168 
  4169 better use "obtain" in situations as above; alternative refer to
  4170 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4171 
  4172 * Pure: proper integration with ``locales''; unlike the original
  4173 version by Florian Kammller, Isar locales package high-level proof
  4174 contexts rather than raw logical ones (e.g. we admit to include
  4175 attributes everywhere); operations on locales include merge and
  4176 rename; support for implicit arguments (``structures''); simultaneous
  4177 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4178 some examples;
  4179 
  4180 * Pure: the following commands have been ``localized'', supporting a
  4181 target locale specification "(in name)": 'lemma', 'theorem',
  4182 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4183 stored both within the locale and at the theory level (exported and
  4184 qualified by the locale name);
  4185 
  4186 * Pure: theory goals may now be specified in ``long'' form, with
  4187 ad-hoc contexts consisting of arbitrary locale elements. for example
  4188 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4189 definitions may be given, too); the result is a meta-level rule with
  4190 the context elements being discharged in the obvious way;
  4191 
  4192 * Pure: new proof command 'using' allows to augment currently used
  4193 facts after a goal statement ('using' is syntactically analogous to
  4194 'apply', but acts on the goal's facts only); this allows chained facts
  4195 to be separated into parts given before and after a claim, as in
  4196 ``from a and b have C using d and e <proof>'';
  4197 
  4198 * Pure: renamed "antecedent" case to "rule_context";
  4199 
  4200 * Pure: new 'judgment' command records explicit information about the
  4201 object-logic embedding (used by several tools internally); no longer
  4202 use hard-wired "Trueprop";
  4203 
  4204 * Pure: added 'corollary' command;
  4205 
  4206 * Pure: fixed 'token_translation' command;
  4207 
  4208 * Pure: removed obsolete 'exported' attribute;
  4209 
  4210 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4211 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4212 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4213 
  4214 * Pure: method 'atomize' presents local goal premises as object-level
  4215 statements (atomic meta-level propositions); setup controlled via
  4216 rewrite rules declarations of 'atomize' attribute; example
  4217 application: 'induct' method with proper rule statements in improper
  4218 proof *scripts*;
  4219 
  4220 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4221 now consider the syntactic context of assumptions, giving a better
  4222 chance to get type-inference of the arguments right (this is
  4223 especially important for locales);
  4224 
  4225 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4226 mode;
  4227 
  4228 * Pure/obtain: the formal conclusion "thesis", being marked as
  4229 ``internal'', may no longer be reference directly in the text;
  4230 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4231 situations;
  4232 
  4233 * Pure: generic 'sym' attribute which declares a rule both as pure
  4234 'elim?' and for the 'symmetric' operation;
  4235 
  4236 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4237 text; the fixed correlation with particular command syntax has been
  4238 discontinued;
  4239 
  4240 * Pure: new method 'rules' is particularly well-suited for proof
  4241 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4242 but often produces more compact proof terms with less detours;
  4243 
  4244 * Pure/Provers/classical: simplified integration with pure rule
  4245 attributes and methods; the classical "intro?/elim?/dest?"
  4246 declarations coincide with the pure ones; the "rule" method no longer
  4247 includes classically swapped intros; "intro" and "elim" methods no
  4248 longer pick rules from the context; also got rid of ML declarations
  4249 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4250 INCOMPATIBILITY;
  4251 
  4252 * Provers/classical: attribute 'swapped' produces classical inversions
  4253 of introduction rules;
  4254 
  4255 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4256 rules instead of full simplifier context; 'iff' attribute handles
  4257 conditional rules;
  4258 
  4259 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4260 
  4261 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4262 "(permissive)" option to recover old behavior;
  4263 
  4264 * HOL: 'inductive' no longer features separate (collective) attributes
  4265 for 'intros' (was found too confusing);
  4266 
  4267 * HOL: properly declared induction rules less_induct and
  4268 wf_induct_rule;
  4269 
  4270 
  4271 *** HOL ***
  4272 
  4273 * HOL: moved over to sane numeral syntax; the new policy is as
  4274 follows:
  4275 
  4276   - 0 and 1 are polymorphic constants, which are defined on any
  4277   numeric type (nat, int, real etc.);
  4278 
  4279   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4280   binary representation internally;
  4281 
  4282   - type nat has special constructor Suc, and generally prefers Suc 0
  4283   over 1::nat and Suc (Suc 0) over 2::nat;
  4284 
  4285 This change may cause significant problems of INCOMPATIBILITY; here
  4286 are some hints on converting existing sources:
  4287 
  4288   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4289   entities, so expressions involving "-" (unary or binary minus) need
  4290   to be spaced properly;
  4291 
  4292   - existing occurrences of "1" may need to be constraint "1::nat" or
  4293   even replaced by Suc 0; similar for old "2";
  4294 
  4295   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4296 
  4297   - remove all special provisions on numerals in proofs;
  4298 
  4299 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4300 representation (depends on bin_arith_simps in the default context);
  4301 
  4302 * HOL: symbolic syntax for x^2 (numeral 2);
  4303 
  4304 * HOL: the class of all HOL types is now called "type" rather than
  4305 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4306 in axclass/classes, instance/arities, and (usually rare) occurrences
  4307 in typings (of consts etc.); internally the class is called
  4308 "HOL.type", ML programs should refer to HOLogic.typeS;
  4309 
  4310 * HOL/record package improvements:
  4311   - new derived operations "fields" to build a partial record section,
  4312     "extend" to promote a fixed record to a record scheme, and
  4313     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4314     declared as simp by default;
  4315   - shared operations ("more", "fields", etc.) now need to be always
  4316     qualified) --- potential INCOMPATIBILITY;
  4317   - removed "make_scheme" operations (use "make" with "extend") --
  4318     INCOMPATIBILITY;
  4319   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4320   - provides cases/induct rules for use with corresponding Isar
  4321     methods (for concrete records, record schemes, concrete more
  4322     parts, and schematic more parts -- in that order);
  4323   - internal definitions directly based on a light-weight abstract
  4324     theory of product types over typedef rather than datatype;
  4325 
  4326 * HOL: generic code generator for generating executable ML code from
  4327 specifications; specific support for HOL constructs such as inductive
  4328 datatypes and sets, as well as recursive functions; can be invoked
  4329 via 'generate_code' theory section;
  4330 
  4331 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4332 
  4333 * HOL: consolidated and renamed several theories.  In particular:
  4334         Ord.thy has been absorbed into HOL.thy
  4335         String.thy has been absorbed into List.thy
  4336 
  4337 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4338 (beware of argument permutation!);
  4339 
  4340 * HOL: linorder_less_split superseded by linorder_cases;
  4341 
  4342 * HOL/List: "nodups" renamed to "distinct";
  4343 
  4344 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4345 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4346   - Ex_def has changed, now need to use some_eq_ex
  4347 
  4348 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4349 in this (rare) case use:
  4350 
  4351   delSWrapper "split_all_tac"
  4352   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4353 
  4354 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4355 MAY FAIL;
  4356 
  4357 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4358 Isabelle's type classes, ^ on functions and relations has too general
  4359 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4360 necessary to attach explicit type constraints;
  4361 
  4362 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4363 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4364 renamed accordingly (eg "compI" -> "rel_compI").
  4365 
  4366 * HOL: syntax translations now work properly with numerals and records
  4367 expressions;
  4368 
  4369 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4370 of "lam" -- INCOMPATIBILITY;
  4371 
  4372 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4373 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4374 renamed "Product_Type.unit";
  4375 
  4376 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4377 
  4378 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4379 the "cases" method);
  4380 
  4381 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4382 Florian Kammller);
  4383 
  4384 * HOL/IMP: updated and converted to new-style theory format; several
  4385 parts turned into readable document, with proper Isar proof texts and
  4386 some explanations (by Gerwin Klein);
  4387 
  4388 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4389 
  4390 * HOL-Hyperreal is now a logic image;
  4391 
  4392 
  4393 *** HOLCF ***
  4394 
  4395 * Isar: consts/constdefs supports mixfix syntax for continuous
  4396 operations;
  4397 
  4398 * Isar: domain package adapted to new-style theory format, e.g. see
  4399 HOLCF/ex/Dnat.thy;
  4400 
  4401 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4402 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4403 lift.induct_tac, always use UU instead of Undef;
  4404 
  4405 * HOLCF/IMP: updated and converted to new-style theory;
  4406 
  4407 
  4408 *** ZF ***
  4409 
  4410 * Isar: proper integration of logic-specific tools and packages,
  4411 including theory commands '(co)inductive', '(co)datatype',
  4412 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4413 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4414 
  4415 * theory Main no longer includes AC; for the Axiom of Choice, base
  4416 your theory on Main_ZFC;
  4417 
  4418 * the integer library now covers quotients and remainders, with many
  4419 laws relating division to addition, multiplication, etc.;
  4420 
  4421 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4422 typeless version of the formalism;
  4423 
  4424 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4425 format;
  4426 
  4427 * ZF/Induct: new directory for examples of inductive definitions,
  4428 including theory Multiset for multiset orderings; converted to
  4429 new-style theory format;
  4430 
  4431 * ZF: many new theorems about lists, ordinals, etc.;
  4432 
  4433 
  4434 *** General ***
  4435 
  4436 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4437 variable proof controls level of detail: 0 = no proofs (only oracle
  4438 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4439 also ref manual for further ML interfaces;
  4440 
  4441 * Pure/axclass: removed obsolete ML interface
  4442 goal_subclass/goal_arity;
  4443 
  4444 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4445 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4446 separate tokens, so expressions involving minus need to be spaced
  4447 properly;
  4448 
  4449 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4450 rather than "infixl" or "infixr";
  4451 
  4452 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4453 sort constraint specifications in type inference; e.g. "x::_::foo"
  4454 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4455 type variable);
  4456 
  4457 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4458 control output of nested => (types); the default behavior is
  4459 "type_brackets";
  4460 
  4461 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4462 tokens into AST constants;
  4463 
  4464 * Pure/syntax: prefer later declarations of translations and print
  4465 translation functions; potential INCOMPATIBILITY: need to reverse
  4466 multiple declarations for same syntax element constant;
  4467 
  4468 * Pure/show_hyps reset by default (in accordance to existing Isar
  4469 practice);
  4470 
  4471 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4472 addSafter;
  4473 
  4474 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4475 as well;
  4476 
  4477 * system: tested support for MacOS X; should be able to get Isabelle +
  4478 Proof General to work in a plain Terminal after installing Poly/ML
  4479 (e.g. from the Isabelle distribution area) and GNU bash alone
  4480 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4481 support requires further installations, e.g. from
  4482 http://fink.sourceforge.net/);
  4483 
  4484 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4485 
  4486 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4487 of 40 MB), cf. ML_OPTIONS;
  4488 
  4489 * system: Proof General keywords specification is now part of the
  4490 Isabelle distribution (see etc/isar-keywords.el);
  4491 
  4492 * system: support for persistent Proof General sessions (refrain from
  4493 outdating all loaded theories on startup); user may create writable
  4494 logic images like this: ``isabelle -q HOL Test'';
  4495 
  4496 * system: smart selection of Isabelle process versus Isabelle
  4497 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4498 run both "isabelle" and "Isabelle" even if file names are badly
  4499 damaged (executable inspects the case of the first letter of its own
  4500 name); added separate "isabelle-process" and "isabelle-interface";
  4501 
  4502 * system: refrain from any attempt at filtering input streams; no
  4503 longer support ``8bit'' encoding of old isabelle font, instead proper
  4504 iso-latin characters may now be used; the related isatools
  4505 "symbolinput" and "nonascii" have disappeared as well;
  4506 
  4507 * system: removed old "xterm" interface (the print modes "xterm" and
  4508 "xterm_color" are still available for direct use in a suitable
  4509 terminal);
  4510 
  4511 
  4512 
  4513 New in Isabelle99-2 (February 2001)
  4514 -----------------------------------
  4515 
  4516 *** Overview of INCOMPATIBILITIES ***
  4517 
  4518 * HOL: please note that theories in the Library and elsewhere often use the
  4519 new-style (Isar) format; to refer to their theorems in an ML script you must
  4520 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4521 
  4522 * HOL: inductive package no longer splits induction rule aggressively,
  4523 but only as far as specified by the introductions given; the old
  4524 format may be recovered via ML function complete_split_rule or attribute
  4525 'split_rule (complete)';
  4526 
  4527 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4528 gfp_Tarski to gfp_unfold;
  4529 
  4530 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4531 
  4532 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4533 relation); infix "^^" has been renamed "``"; infix "``" has been
  4534 renamed "`"; "univalent" has been renamed "single_valued";
  4535 
  4536 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4537 operation;
  4538 
  4539 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4540 
  4541 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4542 
  4543 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4544 consequence, it is no longer monotonic wrt. the local goal context
  4545 (which is now passed through the inductive cases);
  4546 
  4547 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4548 \<gg> to \<ggreater>;
  4549 
  4550 
  4551 *** Document preparation ***
  4552 
  4553 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4554 available: are "it" for near math-mode best-style output, "sl" for
  4555 slanted text style, and "tt" for plain type-writer; if no
  4556 \isabellestyle command is given, output is according to slanted
  4557 type-writer);
  4558 
  4559 * support sub/super scripts (for single symbols only), input syntax is
  4560 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4561 
  4562 * some more standard symbols; see Appendix A of the system manual for
  4563 the complete list of symbols defined in isabellesym.sty;
  4564 
  4565 * improved isabelle style files; more abstract symbol implementation
  4566 (should now use \isamath{...} and \isatext{...} in custom symbol
  4567 definitions);
  4568 
  4569 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4570 state; Note that presentation of goal states does not conform to
  4571 actual human-readable proof documents.  Please do not include goal
  4572 states into document output unless you really know what you are doing!
  4573 
  4574 * proper indentation of antiquoted output with proportional LaTeX
  4575 fonts;
  4576 
  4577 * no_document ML operator temporarily disables LaTeX document
  4578 generation;
  4579 
  4580 * isatool unsymbolize tunes sources for plain ASCII communication;
  4581 
  4582 
  4583 *** Isar ***
  4584 
  4585 * Pure: Isar now suffers initial goal statements to contain unbound
  4586 schematic variables (this does not conform to actual readable proof
  4587 documents, due to unpredictable outcome and non-compositional proof
  4588 checking); users who know what they are doing may use schematic goals
  4589 for Prolog-style synthesis of proven results;
  4590 
  4591 * Pure: assumption method (an implicit finishing) now handles actual
  4592 rules as well;
  4593 
  4594 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4595 initial goal, declare "that" only as Pure intro (only for single
  4596 steps); the "that" rule assumption may now be involved in implicit
  4597 finishing, thus ".." becomes a feasible for trivial obtains;
  4598 
  4599 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4600 instance proofs may be performed by "..";
  4601 
  4602 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4603 statements as well;
  4604 
  4605 * Pure: more robust selection of calculational rules;
  4606 
  4607 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4608 rule (as well as the assumption rule);
  4609 
  4610 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4611 lemmas, using the graph browser tool;
  4612 
  4613 * Pure: predict failure of "show" in interactive mode;
  4614 
  4615 * Pure: 'thms_containing' now takes actual terms as arguments;
  4616 
  4617 * HOL: improved method 'induct' --- now handles non-atomic goals
  4618 (potential INCOMPATIBILITY); tuned error handling;
  4619 
  4620 * HOL: cases and induct rules now provide explicit hints about the
  4621 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4622 any remaining facts are inserted into the goal verbatim;
  4623 
  4624 * HOL: local contexts (aka cases) may now contain term bindings as
  4625 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4626 the result to be shown in each case;
  4627 
  4628 * HOL: added 'recdef_tc' command;
  4629 
  4630 * isatool convert assists in eliminating legacy ML scripts;
  4631 
  4632 
  4633 *** HOL ***
  4634 
  4635 * HOL/Library: a collection of generic theories to be used together
  4636 with main HOL; the theory loader path already includes this directory
  4637 by default; the following existing theories have been moved here:
  4638 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4639 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4640 
  4641 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4642 modelling and verification task performed in Isabelle/HOL +
  4643 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4644 
  4645 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4646 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4647 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4648 'domain', this makes the theory consistent with mathematical
  4649 literature;
  4650 
  4651 * HOL basics: added overloaded operations "inverse" and "divide"
  4652 (infix "/"), syntax for generic "abs" operation, generic summation
  4653 operator \<Sum>;
  4654 
  4655 * HOL/typedef: simplified package, provide more useful rules (see also
  4656 HOL/subset.thy);
  4657 
  4658 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4659 now expressed as a proper nested rule (old-style tactic scripts may
  4660 require atomize_strip_tac to cope with non-atomic premises);
  4661 
  4662 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4663 to "split_conv" (old name still available for compatibility);
  4664 
  4665 * HOL: improved concrete syntax for strings (e.g. allows translation
  4666 rules with string literals);
  4667 
  4668 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4669  and Fleuriot's mechanization of analysis, including the transcendental
  4670  functions for the reals;
  4671 
  4672 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4673 
  4674 
  4675 *** CTT ***
  4676 
  4677 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4678 "lam" is displayed as TWO lambda-symbols
  4679 
  4680 * CTT: theory Main now available, containing everything (that is, Bool
  4681 and Arith);
  4682 
  4683 
  4684 *** General ***
  4685 
  4686 * Pure: the Simplifier has been implemented properly as a derived rule
  4687 outside of the actual kernel (at last!); the overall performance
  4688 penalty in practical applications is about 50%, while reliability of
  4689 the Isabelle inference kernel has been greatly improved;
  4690 
  4691 * print modes "brackets" and "no_brackets" control output of nested =>
  4692 (types) and ==> (props); the default behaviour is "brackets";
  4693 
  4694 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4695 as assumptions as well;
  4696 
  4697 * system: support Poly/ML 4.0;
  4698 
  4699 * system: isatool install handles KDE version 1 or 2;
  4700 
  4701 
  4702 
  4703 New in Isabelle99-1 (October 2000)
  4704 ----------------------------------
  4705 
  4706 *** Overview of INCOMPATIBILITIES ***
  4707 
  4708 * HOL: simplification of natural numbers is much changed; to partly
  4709 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4710 issue the following ML commands:
  4711 
  4712   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4713   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4714 
  4715 * HOL: simplification no longer dives into case-expressions; this is
  4716 controlled by "t.weak_case_cong" for each datatype t;
  4717 
  4718 * HOL: nat_less_induct renamed to less_induct;
  4719 
  4720 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4721 fixsome to patch .thy and .ML sources automatically;
  4722 
  4723   select_equality  -> some_equality
  4724   select_eq_Ex     -> some_eq_ex
  4725   selectI2EX       -> someI2_ex
  4726   selectI2         -> someI2
  4727   selectI          -> someI
  4728   select1_equality -> some1_equality
  4729   Eps_sym_eq       -> some_sym_eq_trivial
  4730   Eps_eq           -> some_eq_trivial
  4731 
  4732 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4733 
  4734 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4735 instead);
  4736 
  4737 * HOL: the recursion equations generated by 'recdef' are now called
  4738 f.simps instead of f.rules;
  4739 
  4740 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4741 
  4742 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4743 sometimes be needed;
  4744 
  4745 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4746 
  4747 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4748 
  4749 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4750 product is now "<*>" instead of "Times"; the lexicographic product is
  4751 now "<*lex*>" instead of "**";
  4752 
  4753 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4754 of main HOL, but was unused); better use HOL's datatype package;
  4755 
  4756 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4757 the old syntax may be recovered as follows:
  4758 
  4759   syntax (symbols)
  4760     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4761       (infixl "\\<oplus>" 100)
  4762 
  4763 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4764 
  4765 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4766 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4767 internally;
  4768 
  4769 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4770 changed from A/r to A//r;
  4771 
  4772 * ZF: new treatment of arithmetic (nat & int) may break some old
  4773 proofs;
  4774 
  4775 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4776 rulify -> rule_format, elimify -> elim_format, ...);
  4777 
  4778 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4779 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4780 should have to change intro!! to intro? only); replaced "delrule" by
  4781 "rule del";
  4782 
  4783 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4784 
  4785 * Provers: strengthened force_tac by using new first_best_tac;
  4786 
  4787 * LaTeX document preparation: several changes of isabelle.sty (see
  4788 lib/texinputs);
  4789 
  4790 
  4791 *** Document preparation ***
  4792 
  4793 * formal comments (text blocks etc.) in new-style theories may now
  4794 contain antiquotations of thm/prop/term/typ/text to be presented
  4795 according to latex print mode; concrete syntax is like this:
  4796 @{term[show_types] "f(x) = a + x"};
  4797 
  4798 * isatool mkdir provides easy setup of Isabelle session directories,
  4799 including proper document sources;
  4800 
  4801 * generated LaTeX sources are now deleted after successful run
  4802 (isatool document -c); may retain a copy somewhere else via -D option
  4803 of isatool usedir;
  4804 
  4805 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4806 style files, achieving self-contained LaTeX sources and simplifying
  4807 LaTeX debugging;
  4808 
  4809 * old-style theories now produce (crude) LaTeX output as well;
  4810 
  4811 * browser info session directories are now self-contained (may be put
  4812 on WWW server seperately); improved graphs of nested sessions; removed
  4813 graph for 'all sessions';
  4814 
  4815 * several improvements in isabelle style files; \isabellestyle{it}
  4816 produces fake math mode output; \isamarkupheader is now \section by
  4817 default; see lib/texinputs/isabelle.sty etc.;
  4818 
  4819 
  4820 *** Isar ***
  4821 
  4822 * Isar/Pure: local results and corresponding term bindings are now
  4823 subject to Hindley-Milner polymorphism (similar to ML); this
  4824 accommodates incremental type-inference very nicely;
  4825 
  4826 * Isar/Pure: new derived language element 'obtain' supports
  4827 generalized existence reasoning;
  4828 
  4829 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4830 support accumulation of results, without applying any rules yet;
  4831 useful to collect intermediate results without explicit name
  4832 references, and for use with transitivity rules with more than 2
  4833 premises;
  4834 
  4835 * Isar/Pure: scalable support for case-analysis type proofs: new
  4836 'case' language element refers to local contexts symbolically, as
  4837 produced by certain proof methods; internally, case names are attached
  4838 to theorems as "tags";
  4839 
  4840 * Isar/Pure: theory command 'hide' removes declarations from
  4841 class/type/const name spaces;
  4842 
  4843 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4844 indicate potential overloading;
  4845 
  4846 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4847 
  4848 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4849 "{a,b,c}" instead of {a,b,c};
  4850 
  4851 * Isar/Pure now provides its own version of intro/elim/dest
  4852 attributes; useful for building new logics, but beware of confusion
  4853 with the version in Provers/classical;
  4854 
  4855 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4856 case name 'antecedent';
  4857 
  4858 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4859 to the current context is now done automatically);
  4860 
  4861 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4862 for definining proof methods in ML;
  4863 
  4864 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4865 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4866 most cases, one should have to change intro!! to intro? only);
  4867 replaced "delrule" by "rule del";
  4868 
  4869 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4870 'symmetric' attribute (the latter supercedes [RS sym]);
  4871 
  4872 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4873 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4874 well (including splits);
  4875 
  4876 * Isar/Provers: Simplifier and Classical methods now support all kind
  4877 of modifiers used in the past, including 'cong', 'iff', etc.
  4878 
  4879 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4880 of Simplifier and Classical reasoner);
  4881 
  4882 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4883 now support named cases; major packages (inductive, datatype, primrec,
  4884 recdef) support case names and properly name parameters;
  4885 
  4886 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4887 monotonicity conditions are extracted to be proven at end of
  4888 calculations;
  4889 
  4890 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4891 method anyway;
  4892 
  4893 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4894 split_if split_if_asm; datatype package provides theorems foo.splits =
  4895 foo.split foo.split_asm for each datatype;
  4896 
  4897 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4898 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4899 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4900 use "(cases (simplified))" method in proper proof texts);
  4901 
  4902 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4903 
  4904 * Isar: names of theorems etc. may be natural numbers as well;
  4905 
  4906 * Isar: 'pr' command: optional arguments for goals_limit and
  4907 ProofContext.prems_limit; no longer prints theory contexts, but only
  4908 proof states;
  4909 
  4910 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4911 additional print modes to be specified; e.g. "pr(latex)" will print
  4912 proof state according to the Isabelle LaTeX style;
  4913 
  4914 * Isar: improved support for emulating tactic scripts, including proof
  4915 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4916 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4917 (for HOL datatypes);
  4918 
  4919 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4920 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4921 'proof method scripts' have to be in depth-first order;
  4922 
  4923 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4924 
  4925 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4926 should instead use individual commands for printing items
  4927 (print_commands, print_methods etc.);
  4928 
  4929 * Isar: added 'nothing' --- the empty list of theorems;
  4930 
  4931 
  4932 *** HOL ***
  4933 
  4934 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4935 corresponding virtual machine and a specification of its bytecode
  4936 verifier and a lightweight bytecode verifier, including proofs of
  4937 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4938 Cornelia Pusch (see also the homepage of project Bali at
  4939 http://isabelle.in.tum.de/Bali/);
  4940 
  4941 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4942 Clemens Ballarin;
  4943 
  4944 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4945 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4946 Rasmussen;
  4947 
  4948 * HOL/Lattice: fundamental concepts of lattice theory and order
  4949 structures, including duals, properties of bounds versus algebraic
  4950 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4951 Theorem for complete lattices etc.; may also serve as a demonstration
  4952 for abstract algebraic reasoning using axiomatic type classes, and
  4953 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4954 
  4955 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4956 von Oheimb;
  4957 
  4958 * HOL/IMPP: extension of IMP with local variables and mutually
  4959 recursive procedures, by David von Oheimb;
  4960 
  4961 * HOL/Lambda: converted into new-style theory and document;
  4962 
  4963 * HOL/ex/Multiquote: example of multiple nested quotations and
  4964 anti-quotations -- basically a generalized version of de-Bruijn
  4965 representation; very useful in avoiding lifting of operations;
  4966 
  4967 * HOL/record: added general record equality rule to simpset; fixed
  4968 select-update simplification procedure to handle extended records as
  4969 well; admit "r" as field name;
  4970 
  4971 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4972 other numeric types and also as the identity of groups, rings, etc.;
  4973 
  4974 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4975 Types nat and int belong to this axclass;
  4976 
  4977 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4978    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4979    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4980   two terms #m*u and #n*u are replaced by #(m+n)*u
  4981     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4982   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4983     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4984 
  4985 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4986 powerful prover for predicate logic but knows nothing of clasets; see
  4987 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4988 
  4989 * HOL: new version of "case_tac" subsumes both boolean case split and
  4990 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4991 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4992 
  4993 * HOL: simplification no longer dives into case-expressions: only the
  4994 selector expression is simplified, but not the remaining arms; to
  4995 enable full simplification of case-expressions for datatype t, you may
  4996 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4997 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4998 
  4999 * HOL/recdef: the recursion equations generated by 'recdef' for
  5000 function 'f' are now called f.simps instead of f.rules; if all
  5001 termination conditions are proved automatically, these simplification
  5002 rules are added to the simpset, as in primrec; rules may be named
  5003 individually as well, resulting in a separate list of theorems for
  5004 each equation;
  5005 
  5006 * HOL/While is a new theory that provides a while-combinator. It
  5007 permits the definition of tail-recursive functions without the
  5008 provision of a termination measure. The latter is necessary once the
  5009 invariant proof rule for while is applied.
  5010 
  5011 * HOL: new (overloaded) notation for the set of elements below/above
  5012 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5013 
  5014 * HOL: theorems impI, allI, ballI bound as "strip";
  5015 
  5016 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5017 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5018 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5019 
  5020 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5021 
  5022 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5023 main HOL, but was unused);
  5024 
  5025 * HOL: fewer consts declared as global (e.g. have to refer to
  5026 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5027 
  5028 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5029 in case of overlap with user translations (e.g. judgements over
  5030 tuples); (note that the underlying logical represenation is still
  5031 bogus);
  5032 
  5033 
  5034 *** ZF ***
  5035 
  5036 * ZF: simplification automatically cancels common terms in arithmetic
  5037 expressions over nat and int;
  5038 
  5039 * ZF: new treatment of nat to minimize type-checking: all operators
  5040 coerce their operands to a natural number using the function natify,
  5041 making the algebraic laws unconditional;
  5042 
  5043 * ZF: as above, for int: operators coerce their operands to an integer
  5044 using the function intify;
  5045 
  5046 * ZF: the integer library now contains many of the usual laws for the
  5047 orderings, including $<=, and monotonicity laws for $+ and $*;
  5048 
  5049 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5050 simplification;
  5051 
  5052 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5053 to the simplifier and classical reasoner simultaneously;
  5054 
  5055 
  5056 *** General ***
  5057 
  5058 * Provers: blast_tac now handles actual object-logic rules as
  5059 assumptions; note that auto_tac uses blast_tac internally as well;
  5060 
  5061 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5062 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5063 
  5064 * Provers: delrules now handles destruct rules as well (no longer need
  5065 explicit make_elim);
  5066 
  5067 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5068   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5069 use instead the strong form,
  5070   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5071 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5072 from destruct-rules;
  5073 
  5074 * Provers: Simplifier.easy_setup provides a fast path to basic
  5075 Simplifier setup for new object-logics;
  5076 
  5077 * Pure: AST translation rules no longer require constant head on LHS;
  5078 
  5079 * Pure: improved name spaces: ambiguous output is qualified; support
  5080 for hiding of names;
  5081 
  5082 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5083 XSYMBOL_HOME; no longer need to do manual configuration in most
  5084 situations;
  5085 
  5086 * system: compression of ML heaps images may now be controlled via -c
  5087 option of isabelle and isatool usedir (currently only observed by
  5088 Poly/ML);
  5089 
  5090 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5091 useful for remote X11);
  5092 
  5093 * system: provide TAGS file for Isabelle sources;
  5094 
  5095 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5096 order;
  5097 
  5098 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5099 timing flag supersedes proof_timing and Toplevel.trace;
  5100 
  5101 * ML: new combinators |>> and |>>> for incremental transformations
  5102 with secondary results (e.g. certain theory extensions):
  5103 
  5104 * ML: PureThy.add_defs gets additional argument to indicate potential
  5105 overloading (usually false);
  5106 
  5107 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5108 results;
  5109 
  5110 
  5111 
  5112 New in Isabelle99 (October 1999)
  5113 --------------------------------
  5114 
  5115 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5116 
  5117 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5118 are no longer simplified.  (This allows the simplifier to unfold recursive
  5119 functional programs.)  To restore the old behaviour, declare
  5120 
  5121     Delcongs [if_weak_cong];
  5122 
  5123 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5124 complement;
  5125 
  5126 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5127 
  5128 * HOL/datatype: mutual_induct_tac no longer exists --
  5129   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5130 
  5131 * HOL/typedef: fixed type inference for representing set; type
  5132 arguments now have to occur explicitly on the rhs as type constraints;
  5133 
  5134 * ZF: The con_defs part of an inductive definition may no longer refer
  5135 to constants declared in the same theory;
  5136 
  5137 * HOL, ZF: the function mk_cases, generated by the inductive
  5138 definition package, has lost an argument.  To simplify its result, it
  5139 uses the default simpset instead of a supplied list of theorems.
  5140 
  5141 * HOL/List: the constructors of type list are now Nil and Cons;
  5142 
  5143 * Simplifier: the type of the infix ML functions
  5144         setSSolver addSSolver setSolver addSolver
  5145 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5146 for packaging solvers. A solver is created via
  5147         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5148 where the string argument is only a comment.
  5149 
  5150 
  5151 *** Proof tools ***
  5152 
  5153 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5154 decision procedure for linear arithmetic. Currently it is used for
  5155 types `nat', `int', and `real' in HOL (see below); it can, should and
  5156 will be instantiated for other types and logics as well.
  5157 
  5158 * The simplifier now accepts rewrite rules with flexible heads, eg
  5159      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5160   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5161   matching.
  5162 
  5163 
  5164 *** General ***
  5165 
  5166 * New Isabelle/Isar subsystem provides an alternative to traditional
  5167 tactical theorem proving; together with the ProofGeneral/isar user
  5168 interface it offers an interactive environment for developing human
  5169 readable proof documents (Isar == Intelligible semi-automated
  5170 reasoning); for further information see isatool doc isar-ref,
  5171 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5172 
  5173 * improved and simplified presentation of theories: better HTML markup
  5174 (including colors), graph views in several sizes; isatool usedir now
  5175 provides a proper interface for user theories (via -P option); actual
  5176 document preparation based on (PDF)LaTeX is available as well (for
  5177 new-style theories only); see isatool doc system for more information;
  5178 
  5179 * native support for Proof General, both for classic Isabelle and
  5180 Isabelle/Isar;
  5181 
  5182 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5183 using the graph browser tool;
  5184 
  5185 * Isabelle manuals now also available as PDF;
  5186 
  5187 * theory loader rewritten from scratch (may not be fully
  5188 bug-compatible); old loadpath variable has been replaced by show_path,
  5189 add_path, del_path, reset_path functions; new operations such as
  5190 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5191 isatool doc ref);
  5192 
  5193 * improved isatool install: option -k creates KDE application icon,
  5194 option -p DIR installs standalone binaries;
  5195 
  5196 * added ML_PLATFORM setting (useful for cross-platform installations);
  5197 more robust handling of platform specific ML images for SML/NJ;
  5198 
  5199 * the settings environment is now statically scoped, i.e. it is never
  5200 created again in sub-processes invoked from isabelle, isatool, or
  5201 Isabelle;
  5202 
  5203 * path element specification '~~' refers to '$ISABELLE_HOME';
  5204 
  5205 * in locales, the "assumes" and "defines" parts may be omitted if
  5206 empty;
  5207 
  5208 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5209 long arrows);
  5210 
  5211 * new print_mode "HTML";
  5212 
  5213 * new flag show_tags controls display of tags of theorems (which are
  5214 basically just comments that may be attached by some tools);
  5215 
  5216 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5217 mode and goal output format:
  5218 
  5219 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5220 244c244
  5221 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5222 ---
  5223 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5224 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5225 181c181
  5226 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5227 ---
  5228 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5229 
  5230 * function bind_thms stores lists of theorems (cf. bind_thm);
  5231 
  5232 * new shorthand tactics ftac, eatac, datac, fatac;
  5233 
  5234 * qed (and friends) now accept "" as result name; in that case the
  5235 theorem is not stored, but proper checks and presentation of the
  5236 result still apply;
  5237 
  5238 * theorem database now also indexes constants "Trueprop", "all",
  5239 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5240 
  5241 
  5242 *** HOL ***
  5243 
  5244 ** HOL arithmetic **
  5245 
  5246 * There are now decision procedures for linear arithmetic over nat and
  5247 int:
  5248 
  5249 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5250 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5251 are treated as atomic; subformulae not involving type `nat' or `int'
  5252 are ignored; quantified subformulae are ignored unless they are
  5253 positive universal or negative existential. The tactic has to be
  5254 invoked by hand and can be a little bit slow. In particular, the
  5255 running time is exponential in the number of occurrences of `min' and
  5256 `max', and `-' on `nat'.
  5257 
  5258 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5259 (negated) (in)equalities among the premises and the conclusion into
  5260 account (i.e. no compound formulae) and does not know about `min' and
  5261 `max', and `-' on `nat'. It is fast and is used automatically by the
  5262 simplifier.
  5263 
  5264 NB: At the moment, these decision procedures do not cope with mixed
  5265 nat/int formulae where the two parts interact, such as `m < n ==>
  5266 int(m) < int(n)'.
  5267 
  5268 * HOL/Numeral provides a generic theory of numerals (encoded
  5269 efficiently as bit strings); setup for types nat/int/real is in place;
  5270 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5271 int, existing theories and proof scripts may require a few additional
  5272 type constraints;
  5273 
  5274 * integer division and remainder can now be performed on constant
  5275 arguments;
  5276 
  5277 * many properties of integer multiplication, division and remainder
  5278 are now available;
  5279 
  5280 * An interface to the Stanford Validity Checker (SVC) is available through the
  5281 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5282 are proved automatically.  SVC must be installed separately, and its results
  5283 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5284 invocation of the underlying oracle).  For SVC see
  5285   http://verify.stanford.edu/SVC
  5286 
  5287 * IsaMakefile: the HOL-Real target now builds an actual image;
  5288 
  5289 
  5290 ** HOL misc **
  5291 
  5292 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5293 (in Isabelle/Isar) -- by Gertrud Bauer;
  5294 
  5295 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5296 analysis for assembly languages with subtypes;
  5297 
  5298 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5299 -- avoids syntactic ambiguities and treats state, transition, and
  5300 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5301 changed syntax and (many) tactics;
  5302 
  5303 * HOL/inductive: Now also handles more general introduction rules such
  5304   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5305   theorems are now maintained within the theory (maintained via the
  5306   "mono" attribute);
  5307 
  5308 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5309   (using function types) such as
  5310 
  5311   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5312 
  5313 * HOL/record: record_simproc (part of the default simpset) takes care
  5314 of selectors applied to updated records; record_split_tac is no longer
  5315 part of the default claset; update_defs may now be removed from the
  5316 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5317 
  5318   claset_ref () := claset() addSWrapper record_split_wrapper;
  5319   Delsimprocs [record_simproc]
  5320 
  5321 * HOL/typedef: fixed type inference for representing set; type
  5322 arguments now have to occur explicitly on the rhs as type constraints;
  5323 
  5324 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5325 names rather than an ML expression;
  5326 
  5327 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5328 supplied later.  Program schemes can be defined, such as
  5329     "While B C s = (if B s then While B C (C s) else s)"
  5330 where the well-founded relation can be chosen after B and C have been given.
  5331 
  5332 * HOL/List: the constructors of type list are now Nil and Cons;
  5333 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5334 course, ML tools referring to List.list.op # etc. have to be adapted;
  5335 
  5336 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5337 disabled by default; run isabelle with option -m HOL to get back to
  5338 the original Gordon/HOL-style output;
  5339 
  5340 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5341 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5342 
  5343 * HOL basic syntax simplified (more orthogonal): all variants of
  5344 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5345 Eps operator is provided as well: "SOME x. P[x]";
  5346 
  5347 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5348 
  5349 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5350 thus available for user theories;
  5351 
  5352 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5353 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5354 time;
  5355 
  5356 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5357 several times and then mp;
  5358 
  5359 
  5360 *** LK ***
  5361 
  5362 * the notation <<...>> is now available as a notation for sequences of
  5363 formulas;
  5364 
  5365 * the simplifier is now installed
  5366 
  5367 * the axiom system has been generalized (thanks to Soren Heilmann)
  5368 
  5369 * the classical reasoner now has a default rule database
  5370 
  5371 
  5372 *** ZF ***
  5373 
  5374 * new primrec section allows primitive recursive functions to be given
  5375 directly (as in HOL) over datatypes and the natural numbers;
  5376 
  5377 * new tactics induct_tac and exhaust_tac for induction (or case
  5378 analysis) over datatypes and the natural numbers;
  5379 
  5380 * the datatype declaration of type T now defines the recursor T_rec;
  5381 
  5382 * simplification automatically does freeness reasoning for datatype
  5383 constructors;
  5384 
  5385 * automatic type-inference, with AddTCs command to insert new
  5386 type-checking rules;
  5387 
  5388 * datatype introduction rules are now added as Safe Introduction rules
  5389 to the claset;
  5390 
  5391 * the syntax "if P then x else y" is now available in addition to
  5392 if(P,x,y);
  5393 
  5394 
  5395 *** Internal programming interfaces ***
  5396 
  5397 * tuned simplifier trace output; new flag debug_simp;
  5398 
  5399 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5400 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5401 
  5402 * AxClass.axclass_tac lost the theory argument;
  5403 
  5404 * tuned current_goals_markers semantics: begin / end goal avoids
  5405 printing empty lines;
  5406 
  5407 * removed prs and prs_fn hook, which was broken because it did not
  5408 include \n in its semantics, forcing writeln to add one
  5409 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5410 string -> unit if you really want to output text without newline;
  5411 
  5412 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5413 plain output, interface builders may have to enable 'isabelle_font'
  5414 mode to get Isabelle font glyphs as before;
  5415 
  5416 * refined token_translation interface; INCOMPATIBILITY: output length
  5417 now of type real instead of int;
  5418 
  5419 * theory loader actions may be traced via new ThyInfo.add_hook
  5420 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5421 your own database of information attached to *whole* theories -- as
  5422 opposed to intra-theory data slots offered via TheoryDataFun;
  5423 
  5424 * proper handling of dangling sort hypotheses (at last!);
  5425 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5426 extra sort hypotheses that can be witnessed from the type signature;
  5427 the force_strip_shyps flag is gone, any remaining shyps are simply
  5428 left in the theorem (with a warning issued by strip_shyps_warning);
  5429 
  5430 
  5431 
  5432 New in Isabelle98-1 (October 1998)
  5433 ----------------------------------
  5434 
  5435 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5436 
  5437 * several changes of automated proof tools;
  5438 
  5439 * HOL: major changes to the inductive and datatype packages, including
  5440 some minor incompatibilities of theory syntax;
  5441 
  5442 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5443 called `inj_on';
  5444 
  5445 * HOL: removed duplicate thms in Arith:
  5446   less_imp_add_less  should be replaced by  trans_less_add1
  5447   le_imp_add_le      should be replaced by  trans_le_add1
  5448 
  5449 * HOL: unary minus is now overloaded (new type constraints may be
  5450 required);
  5451 
  5452 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5453 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5454 now taken as an integer constant.
  5455 
  5456 * Pure: ML function 'theory_of' renamed to 'theory';
  5457 
  5458 
  5459 *** Proof tools ***
  5460 
  5461 * Simplifier:
  5462   1. Asm_full_simp_tac is now more aggressive.
  5463      1. It will sometimes reorient premises if that increases their power to
  5464         simplify.
  5465      2. It does no longer proceed strictly from left to right but may also
  5466         rotate premises to achieve further simplification.
  5467      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5468      old Asm_full_simp_tac in that it does not rotate premises.
  5469   2. The simplifier now knows a little bit about nat-arithmetic.
  5470 
  5471 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5472 allows for selected deletion of wrappers, by introduction of names for
  5473 wrapper functionals.  This implies that addbefore, addSbefore,
  5474 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5475 and that adding two tactics with the same name overwrites the first
  5476 one (emitting a warning).
  5477   type wrapper = (int -> tactic) -> (int -> tactic)
  5478   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5479   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5480   delWrapper, delSWrapper: claset *  string            -> claset
  5481   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5482 
  5483 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5484 semantics; addbefore now affects only the unsafe part of step_tac
  5485 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5486 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5487 by Force_tac;
  5488 
  5489 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5490 compWrapper; added safe wrapper (and access functions for it);
  5491 
  5492 * HOL/split_all_tac is now much faster and fails if there is nothing
  5493 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5494 and the names of the automatically generated variables have changed.
  5495 split_all_tac has moved within claset() from unsafe wrappers to safe
  5496 wrappers, which means that !!-bound variables are split much more
  5497 aggressively, and safe_tac and clarify_tac now split such variables.
  5498 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5499 Note: the same holds for record_split_tac, which does the job of
  5500 split_all_tac for record fields.
  5501 
  5502 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5503 permanently to the default simpset using Addsplits just like
  5504 Addsimps. They can be removed via Delsplits just like
  5505 Delsimps. Lower-case versions are also available.
  5506 
  5507 * HOL/Simplifier: The rule split_if is now part of the default
  5508 simpset. This means that the simplifier will eliminate all occurrences
  5509 of if-then-else in the conclusion of a goal. To prevent this, you can
  5510 either remove split_if completely from the default simpset by
  5511 `Delsplits [split_if]' or remove it in a specific call of the
  5512 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5513 other case splitting rules to/from the default simpset: every datatype
  5514 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5515 t is the name of the datatype).
  5516 
  5517 * Classical reasoner / Simplifier combination: new force_tac (and
  5518 derivatives Force_tac, force) combines rewriting and classical
  5519 reasoning (and whatever other tools) similarly to auto_tac, but is
  5520 aimed to solve the given subgoal completely.
  5521 
  5522 
  5523 *** General ***
  5524 
  5525 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5526 and `goalw': the theory is no longer needed as an explicit argument -
  5527 the current theory context is used; assumptions are no longer returned
  5528 at the ML-level unless one of them starts with ==> or !!; it is
  5529 recommended to convert to these new commands using isatool fixgoal
  5530 (backup your sources first!);
  5531 
  5532 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5533 the current theory context, and 'theory' to lookup stored theories;
  5534 
  5535 * new theory section 'locale' for declaring constants, assumptions and
  5536 definitions that have local scope;
  5537 
  5538 * new theory section 'nonterminals' for purely syntactic types;
  5539 
  5540 * new theory section 'setup' for generic ML setup functions
  5541 (e.g. package initialization);
  5542 
  5543 * the distribution now includes Isabelle icons: see
  5544 lib/logo/isabelle-{small,tiny}.xpm;
  5545 
  5546 * isatool install - install binaries with absolute references to
  5547 ISABELLE_HOME/bin;
  5548 
  5549 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5550 
  5551 * print mode 'emacs' reserved for Isamode;
  5552 
  5553 * support multiple print (ast) translations per constant name;
  5554 
  5555 * theorems involving oracles are now printed with a suffixed [!];
  5556 
  5557 
  5558 *** HOL ***
  5559 
  5560 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5561 
  5562 * HOL/inductive package reorganized and improved: now supports mutual
  5563 definitions such as
  5564 
  5565   inductive EVEN ODD
  5566     intrs
  5567       null "0 : EVEN"
  5568       oddI "n : EVEN ==> Suc n : ODD"
  5569       evenI "n : ODD ==> Suc n : EVEN"
  5570 
  5571 new theorem list "elims" contains an elimination rule for each of the
  5572 recursive sets; inductive definitions now handle disjunctive premises
  5573 correctly (also ZF);
  5574 
  5575 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5576 "mutual_induct" no longer exists - the induction rule is always
  5577 contained in "induct";
  5578 
  5579 
  5580 * HOL/datatype package re-implemented and greatly improved: now
  5581 supports mutually recursive datatypes such as
  5582 
  5583   datatype
  5584     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5585             | SUM ('a aexp) ('a aexp)
  5586             | DIFF ('a aexp) ('a aexp)
  5587             | NUM 'a
  5588   and
  5589     'a bexp = LESS ('a aexp) ('a aexp)
  5590             | AND ('a bexp) ('a bexp)
  5591             | OR ('a bexp) ('a bexp)
  5592 
  5593 as well as indirectly recursive datatypes such as
  5594 
  5595   datatype
  5596     ('a, 'b) term = Var 'a
  5597                   | App 'b ((('a, 'b) term) list)
  5598 
  5599 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5600 induction on mutually / indirectly recursive datatypes.
  5601 
  5602 Primrec equations are now stored in theory and can be accessed via
  5603 <function_name>.simps.
  5604 
  5605 INCOMPATIBILITIES:
  5606 
  5607   - Theories using datatypes must now have theory Datatype as an
  5608     ancestor.
  5609   - The specific <typename>.induct_tac no longer exists - use the
  5610     generic induct_tac instead.
  5611   - natE has been renamed to nat.exhaust - use exhaust_tac
  5612     instead of res_inst_tac ... natE. Note that the variable
  5613     names in nat.exhaust differ from the names in natE, this
  5614     may cause some "fragile" proofs to fail.
  5615   - The theorems split_<typename>_case and split_<typename>_case_asm
  5616     have been renamed to <typename>.split and <typename>.split_asm.
  5617   - Since default sorts of type variables are now handled correctly,
  5618     some datatype definitions may have to be annotated with explicit
  5619     sort constraints.
  5620   - Primrec definitions no longer require function name and type
  5621     of recursive argument.
  5622 
  5623 Consider using isatool fixdatatype to adapt your theories and proof
  5624 scripts to the new package (backup your sources first!).
  5625 
  5626 
  5627 * HOL/record package: considerably improved implementation; now
  5628 includes concrete syntax for record types, terms, updates; theorems
  5629 for surjective pairing and splitting !!-bound record variables; proof
  5630 support is as follows:
  5631 
  5632   1) standard conversions (selectors or updates applied to record
  5633 constructor terms) are part of the standard simpset;
  5634 
  5635   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5636 made part of standard simpset and claset via addIffs;
  5637 
  5638   3) a tactic for record field splitting (record_split_tac) is part of
  5639 the standard claset (addSWrapper);
  5640 
  5641 To get a better idea about these rules you may retrieve them via
  5642 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5643 the name of your record type.
  5644 
  5645 The split tactic 3) conceptually simplifies by the following rule:
  5646 
  5647   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5648 
  5649 Thus any record variable that is bound by meta-all will automatically
  5650 blow up into some record constructor term, consequently the
  5651 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5652 solve record problems automatically.
  5653 
  5654 
  5655 * reorganized the main HOL image: HOL/Integ and String loaded by
  5656 default; theory Main includes everything;
  5657 
  5658 * automatic simplification of integer sums and comparisons, using cancellation;
  5659 
  5660 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5661 
  5662 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5663 
  5664 * many new identities for unions, intersections, set difference, etc.;
  5665 
  5666 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5667 called split_if, split_split, split_sum_case and split_nat_case (to go
  5668 with add/delsplits);
  5669 
  5670 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5671 (?x::unit) = (); this is made part of the default simpset, which COULD
  5672 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5673 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5674 unit_abs_eta_conv is added in order to counter the effect of
  5675 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5676 %u.f();
  5677 
  5678 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5679 makes more sense);
  5680 
  5681 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5682   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5683   disjointness reasoning but breaking a few old proofs.
  5684 
  5685 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5686 to 'converse' from 'inverse' (for compatibility with ZF and some
  5687 literature);
  5688 
  5689 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5690 the well-founded relation;
  5691 
  5692 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5693     Compl A.  The "Compl" syntax remains available as input syntax for this
  5694     release ONLY.
  5695 
  5696 * HOL/Update: new theory of function updates:
  5697     f(a:=b) == %x. if x=a then b else f x
  5698 may also be iterated as in f(a:=b,c:=d,...);
  5699 
  5700 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5701 
  5702 * HOL/List:
  5703   - new function list_update written xs[i:=v] that updates the i-th
  5704     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5705   - new function `upt' written [i..j(] which generates the list
  5706     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5707     bound write [i..j], which is a shorthand for [i..j+1(].
  5708   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5709 
  5710 * HOL/Arith:
  5711   - removed 'pred' (predecessor) function;
  5712   - generalized some theorems about n-1;
  5713   - many new laws about "div" and "mod";
  5714   - new laws about greatest common divisors (see theory ex/Primes);
  5715 
  5716 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5717 instead of "inverse";
  5718 
  5719 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5720   of the multiset ordering;
  5721 
  5722 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5723   (not included by default);
  5724 
  5725 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5726 
  5727 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5728   programs, i.e. different program variables may have different types.
  5729 
  5730 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5731   [previously, this check worked only if the rewrite rule was unconditional]
  5732   Now rew can involve either definitions or equalities (either == or =).
  5733 
  5734 
  5735 *** ZF ***
  5736 
  5737 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5738   only the theorems proved on ZF.ML;
  5739 
  5740 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5741   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5742   disjointness reasoning but breaking a few old proofs.
  5743 
  5744 * ZF/Update: new theory of function updates
  5745     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5746   may also be iterated as in f(a:=b,c:=d,...);
  5747 
  5748 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5749 
  5750 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5751   [previously, this check worked only if the rewrite rule was unconditional]
  5752   Now rew can involve either definitions or equalities (either == or =).
  5753 
  5754 * case_tac provided for compatibility with HOL
  5755     (like the old excluded_middle_tac, but with subgoals swapped)
  5756 
  5757 
  5758 *** Internal programming interfaces ***
  5759 
  5760 * Pure: several new basic modules made available for general use, see
  5761 also src/Pure/README;
  5762 
  5763 * improved the theory data mechanism to support encapsulation (data
  5764 kind name replaced by private Object.kind, acting as authorization
  5765 key); new type-safe user interface via functor TheoryDataFun; generic
  5766 print_data function becomes basically useless;
  5767 
  5768 * removed global_names compatibility flag -- all theory declarations
  5769 are qualified by default;
  5770 
  5771 * module Pure/Syntax now offers quote / antiquote translation
  5772 functions (useful for Hoare logic etc. with implicit dependencies);
  5773 see HOL/ex/Antiquote for an example use;
  5774 
  5775 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5776 cterm -> thm;
  5777 
  5778 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5779 subgoal;
  5780 
  5781 * Display.print_goals function moved to Locale.print_goals;
  5782 
  5783 * standard print function for goals supports current_goals_markers
  5784 variable for marking begin of proof, end of proof, start of goal; the
  5785 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5786 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5787 for example;
  5788 
  5789 
  5790 
  5791 New in Isabelle98 (January 1998)
  5792 --------------------------------
  5793 
  5794 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5795 
  5796 * changed lexical syntax of terms / types: dots made part of long
  5797 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5798 
  5799 * simpset (and claset) reference variable replaced by functions
  5800 simpset / simpset_ref;
  5801 
  5802 * no longer supports theory aliases (via merge) and non-trivial
  5803 implicit merge of thms' signatures;
  5804 
  5805 * most internal names of constants changed due to qualified names;
  5806 
  5807 * changed Pure/Sequence interface (see Pure/seq.ML);
  5808 
  5809 
  5810 *** General Changes ***
  5811 
  5812 * hierachically structured name spaces (for consts, types, axms, thms
  5813 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5814 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5815 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5816 long_names for fully qualified output names; NOTE: ML programs
  5817 (special tactics, packages etc.) referring to internal names may have
  5818 to be adapted to cope with fully qualified names; in case of severe
  5819 backward campatibility problems try setting 'global_names' at compile
  5820 time to have enrything declared within a flat name space; one may also
  5821 fine tune name declarations in theories via the 'global' and 'local'
  5822 section;
  5823 
  5824 * reimplemented the implicit simpset and claset using the new anytype
  5825 data filed in signatures; references simpset:simpset ref etc. are
  5826 replaced by functions simpset:unit->simpset and
  5827 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5828 to patch your ML files accordingly;
  5829 
  5830 * HTML output now includes theory graph data for display with Java
  5831 applet or isatool browser; data generated automatically via isatool
  5832 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5833 
  5834 * defs may now be conditional; improved rewrite_goals_tac to handle
  5835 conditional equations;
  5836 
  5837 * defs now admits additional type arguments, using TYPE('a) syntax;
  5838 
  5839 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5840 creates a new theory node; implicit merge of thms' signatures is
  5841 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5842 transfer:theory->thm->thm in (rare) cases;
  5843 
  5844 * improved handling of draft signatures / theories; draft thms (and
  5845 ctyps, cterms) are automatically promoted to real ones;
  5846 
  5847 * slightly changed interfaces for oracles: admit many per theory, named
  5848 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5849 
  5850 * print_goals: optional output of const types (set show_consts and
  5851 show_types);
  5852 
  5853 * improved output of warnings (###) and errors (***);
  5854 
  5855 * subgoal_tac displays a warning if the new subgoal has type variables;
  5856 
  5857 * removed old README and Makefiles;
  5858 
  5859 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5860 
  5861 * removed obsolete init_pps and init_database;
  5862 
  5863 * deleted the obsolete tactical STATE, which was declared by
  5864     fun STATE tacfun st = tacfun st st;
  5865 
  5866 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5867 (which abbreviates $HOME);
  5868 
  5869 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5870 use isatool fixseq to adapt your ML programs (this works for fully
  5871 qualified references to the Sequence structure only!);
  5872 
  5873 * use_thy no longer requires writable current directory; it always
  5874 reloads .ML *and* .thy file, if either one is out of date;
  5875 
  5876 
  5877 *** Classical Reasoner ***
  5878 
  5879 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5880 tactics that use classical reasoning to simplify a subgoal without
  5881 splitting it into several subgoals;
  5882 
  5883 * Safe_tac: like safe_tac but uses the default claset;
  5884 
  5885 
  5886 *** Simplifier ***
  5887 
  5888 * added simplification meta rules:
  5889     (asm_)(full_)simplify: simpset -> thm -> thm;
  5890 
  5891 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5892 logics (again);
  5893 
  5894 * added prems argument to simplification procedures;
  5895 
  5896 * HOL, FOL, ZF: added infix function `addsplits':
  5897   instead of `<simpset> setloop (split_tac <thms>)'
  5898   you can simply write `<simpset> addsplits <thms>'
  5899 
  5900 
  5901 *** Syntax ***
  5902 
  5903 * TYPE('a) syntax for type reflection terms;
  5904 
  5905 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5906 
  5907 * pretty printer: changed order of mixfix annotation preference (again!);
  5908 
  5909 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5910 
  5911 
  5912 *** HOL ***
  5913 
  5914 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5915   with `addloop' of the simplifier to faciliate case splitting in premises.
  5916 
  5917 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5918 
  5919 * HOL/Auth: new protocol proofs including some for the Internet
  5920   protocol TLS;
  5921 
  5922 * HOL/Map: new theory of `maps' a la VDM;
  5923 
  5924 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5925 cancelling out common nat summands from =, <, <= (in)equalities, or
  5926 differences; simplification procedures nat_cancel_factor for
  5927 cancelling common factor from =, <, <= (in)equalities over natural
  5928 sums; nat_cancel contains both kinds of procedures, it is installed by
  5929 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5930 
  5931 * HOL/simplifier: terms of the form
  5932   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5933   are rewritten to
  5934   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5935   and those of the form
  5936   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5937   are rewritten to
  5938   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5939 
  5940 * HOL/datatype
  5941   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5942 
  5943   P(t_case f1 ... fn x) =
  5944      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5945         ...
  5946        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5947      )
  5948 
  5949   and a theorem `split_t_case_asm' of the form
  5950 
  5951   P(t_case f1 ... fn x) =
  5952     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5953         ...
  5954        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5955      )
  5956   which can be added to a simpset via `addsplits'. The existing theorems
  5957   expand_list_case and expand_option_case have been renamed to
  5958   split_list_case and split_option_case.
  5959 
  5960 * HOL/Arithmetic:
  5961   - `pred n' is automatically converted to `n-1'.
  5962     Users are strongly encouraged not to use `pred' any longer,
  5963     because it will disappear altogether at some point.
  5964   - Users are strongly encouraged to write "0 < n" rather than
  5965     "n ~= 0". Theorems and proof tools have been modified towards this
  5966     `standard'.
  5967 
  5968 * HOL/Lists:
  5969   the function "set_of_list" has been renamed "set" (and its theorems too);
  5970   the function "nth" now takes its arguments in the reverse order and
  5971   has acquired the infix notation "!" as in "xs!n".
  5972 
  5973 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5974 
  5975 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5976   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5977 
  5978 * HOL/record: extensible records with schematic structural subtyping
  5979 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5980 still lacks various theorems and concrete record syntax;
  5981 
  5982 
  5983 *** HOLCF ***
  5984 
  5985 * removed "axioms" and "generated by" sections;
  5986 
  5987 * replaced "ops" section by extended "consts" section, which is capable of
  5988   handling the continuous function space "->" directly;
  5989 
  5990 * domain package:
  5991   . proves theorems immediately and stores them in the theory,
  5992   . creates hierachical name space,
  5993   . now uses normal mixfix annotations (instead of cinfix...),
  5994   . minor changes to some names and values (for consistency),
  5995   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5996   . separator between mutual domain defs: changed "," to "and",
  5997   . improved handling of sort constraints;  now they have to
  5998     appear on the left-hand side of the equations only;
  5999 
  6000 * fixed LAM <x,y,zs>.b syntax;
  6001 
  6002 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  6003 adm (%x. P (t x)), where P is chainfinite and t continuous;
  6004 
  6005 
  6006 *** FOL and ZF ***
  6007 
  6008 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6009   with `addloop' of the simplifier to faciliate case splitting in premises.
  6010 
  6011 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6012 in HOL, they strip ALL and --> from proved theorems;
  6013 
  6014 
  6015 
  6016 New in Isabelle94-8 (May 1997)
  6017 ------------------------------
  6018 
  6019 *** General Changes ***
  6020 
  6021 * new utilities to build / run / maintain Isabelle etc. (in parts
  6022 still somewhat experimental); old Makefiles etc. still functional;
  6023 
  6024 * new 'Isabelle System Manual';
  6025 
  6026 * INSTALL text, together with ./configure and ./build scripts;
  6027 
  6028 * reimplemented type inference for greater efficiency, better error
  6029 messages and clean internal interface;
  6030 
  6031 * prlim command for dealing with lots of subgoals (an easier way of
  6032 setting goals_limit);
  6033 
  6034 
  6035 *** Syntax ***
  6036 
  6037 * supports alternative (named) syntax tables (parser and pretty
  6038 printer); internal interface is provided by add_modesyntax(_i);
  6039 
  6040 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6041 be used in conjunction with the Isabelle symbol font; uses the
  6042 "symbols" syntax table;
  6043 
  6044 * added token_translation interface (may translate name tokens in
  6045 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6046 the current print_mode); IMPORTANT: user print translation functions
  6047 are responsible for marking newly introduced bounds
  6048 (Syntax.mark_boundT);
  6049 
  6050 * token translations for modes "xterm" and "xterm_color" that display
  6051 names in bold, underline etc. or colors (which requires a color
  6052 version of xterm);
  6053 
  6054 * infixes may now be declared with names independent of their syntax;
  6055 
  6056 * added typed_print_translation (like print_translation, but may
  6057 access type of constant);
  6058 
  6059 
  6060 *** Classical Reasoner ***
  6061 
  6062 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6063 some limitations.  Blast_tac...
  6064   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6065   + ignores elimination rules that don't have the correct format
  6066         (the conclusion MUST be a formula variable)
  6067   + ignores types, which can make HOL proofs fail
  6068   + rules must not require higher-order unification, e.g. apply_type in ZF
  6069     [message "Function Var's argument not a bound variable" relates to this]
  6070   + its proof strategy is more general but can actually be slower
  6071 
  6072 * substitution with equality assumptions no longer permutes other
  6073 assumptions;
  6074 
  6075 * minor changes in semantics of addafter (now called addaltern); renamed
  6076 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6077 (and access functions for it);
  6078 
  6079 * improved combination of classical reasoner and simplifier:
  6080   + functions for handling clasimpsets
  6081   + improvement of addss: now the simplifier is called _after_ the
  6082     safe steps.
  6083   + safe variant of addss called addSss: uses safe simplifications
  6084     _during_ the safe steps. It is more complete as it allows multiple
  6085     instantiations of unknowns (e.g. with slow_tac).
  6086 
  6087 *** Simplifier ***
  6088 
  6089 * added interface for simplification procedures (functions that
  6090 produce *proven* rewrite rules on the fly, depending on current
  6091 redex);
  6092 
  6093 * ordering on terms as parameter (used for ordered rewriting);
  6094 
  6095 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6096 
  6097 * the solver is now split into a safe and an unsafe part.
  6098 This should be invisible for the normal user, except that the
  6099 functions setsolver and addsolver have been renamed to setSolver and
  6100 addSolver; added safe_asm_full_simp_tac;
  6101 
  6102 
  6103 *** HOL ***
  6104 
  6105 * a generic induction tactic `induct_tac' which works for all datatypes and
  6106 also for type `nat';
  6107 
  6108 * a generic case distinction tactic `exhaust_tac' which works for all
  6109 datatypes and also for type `nat';
  6110 
  6111 * each datatype comes with a function `size';
  6112 
  6113 * patterns in case expressions allow tuple patterns as arguments to
  6114 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6115 
  6116 * primrec now also works with type nat;
  6117 
  6118 * recdef: a new declaration form, allows general recursive functions to be
  6119 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6120 
  6121 * the constant for negation has been renamed from "not" to "Not" to
  6122 harmonize with FOL, ZF, LK, etc.;
  6123 
  6124 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6125 infinite lists;
  6126 
  6127 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6128 
  6129 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6130 problems in commutative rings, using axiomatic type classes for + and *;
  6131 
  6132 * more examples in HOL/MiniML and HOL/Auth;
  6133 
  6134 * more default rewrite rules for quantifiers, union/intersection;
  6135 
  6136 * a new constant `arbitrary == @x.False';
  6137 
  6138 * HOLCF/IOA replaces old HOL/IOA;
  6139 
  6140 * HOLCF changes: derived all rules and arities
  6141   + axiomatic type classes instead of classes
  6142   + typedef instead of faking type definitions
  6143   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6144   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6145   + eliminated the types void, one, tr
  6146   + use unit lift and bool lift (with translations) instead of one and tr
  6147   + eliminated blift from Lift3.thy (use Def instead of blift)
  6148   all eliminated rules are derived as theorems --> no visible changes ;
  6149 
  6150 
  6151 *** ZF ***
  6152 
  6153 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6154 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6155 as ZF_cs addSIs [equalityI];
  6156 
  6157 
  6158 
  6159 New in Isabelle94-7 (November 96)
  6160 ---------------------------------
  6161 
  6162 * allowing negative levels (as offsets) in prlev and choplev;
  6163 
  6164 * super-linear speedup for large simplifications;
  6165 
  6166 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6167 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6168 FAIL); can suppress it using the command Delsimps (ex_simps @
  6169 all_simps); De Morgan laws are also now included, by default;
  6170 
  6171 * improved printing of ==>  :  ~:
  6172 
  6173 * new object-logic "Sequents" adds linear logic, while replacing LK
  6174 and Modal (thanks to Sara Kalvala);
  6175 
  6176 * HOL/Auth: correctness proofs for authentication protocols;
  6177 
  6178 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6179 examples on HOL/Auth);
  6180 
  6181 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6182 the rewriter and classical reasoner simultaneously;
  6183 
  6184 * function uresult no longer returns theorems in "standard" format;
  6185 regain previous version by: val uresult = standard o uresult;
  6186 
  6187 
  6188 
  6189 New in Isabelle94-6
  6190 -------------------
  6191 
  6192 * oracles -- these establish an interface between Isabelle and trusted
  6193 external reasoners, which may deliver results as theorems;
  6194 
  6195 * proof objects (in particular record all uses of oracles);
  6196 
  6197 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6198 
  6199 * "constdefs" section in theory files;
  6200 
  6201 * "primrec" section (HOL) no longer requires names;
  6202 
  6203 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6204 
  6205 
  6206 
  6207 New in Isabelle94-5
  6208 -------------------
  6209 
  6210 * reduced space requirements;
  6211 
  6212 * automatic HTML generation from theories;
  6213 
  6214 * theory files no longer require "..." (quotes) around most types;
  6215 
  6216 * new examples, including two proofs of the Church-Rosser theorem;
  6217 
  6218 * non-curried (1994) version of HOL is no longer distributed;
  6219 
  6220 
  6221 
  6222 New in Isabelle94-4
  6223 -------------------
  6224 
  6225 * greatly reduced space requirements;
  6226 
  6227 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6228 
  6229 * searchable theorem database (see the section "Retrieving theorems" on
  6230 page 8 of the Reference Manual);
  6231 
  6232 * new examples, including Grabczewski's monumental case study of the
  6233 Axiom of Choice;
  6234 
  6235 * The previous version of HOL renamed to Old_HOL;
  6236 
  6237 * The new version of HOL (previously called CHOL) uses a curried syntax
  6238 for functions.  Application looks like f a b instead of f(a,b);
  6239 
  6240 * Mutually recursive inductive definitions finally work in HOL;
  6241 
  6242 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6243 translates to the operator "split";
  6244 
  6245 
  6246 
  6247 New in Isabelle94-3
  6248 -------------------
  6249 
  6250 * new infix operator, addss, allowing the classical reasoner to
  6251 perform simplification at each step of its search.  Example:
  6252         fast_tac (cs addss ss)
  6253 
  6254 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6255 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6256 look like (a,b) instead of <a,b>;
  6257 
  6258 * PLEASE NOTE: CHOL will eventually replace HOL!
  6259 
  6260 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6261 It translates to the operator "split".  A new theory of integers is available;