NEWS
author haftmann
Thu Apr 16 10:11:34 2009 +0200 (2009-04-16)
changeset 30930 11010e5f18f0
parent 30855 c22436e6d350
child 30949 37f887b55e7f
permissions -rw-r--r--
tightended specification of class semiring_div
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 *** HOL ***
     5 
     6 * Class semiring_div now requires no_zero_divisors and proof of div_mult_mult1;
     7 theorems div_mult_mult1, div_mult_mult2, div_mult_mult1_if, div_mult_mult1 and
     8 div_mult_mult2 have been generalized to class semiring_div, subsuming former
     9 theorems zdiv_zmult_zmult1, zdiv_zmult_zmult1_if, zdiv_zmult_zmult1 and zdiv_zmult_zmult2.
    10 div_mult_mult1 is now [simp] by default.  INCOMPATIBILITY.
    11 
    12 New in Isabelle2009 (April 2009)
    13 --------------------------------
    14 
    15 *** General ***
    16 
    17 * Simplified main Isabelle executables, with less surprises on
    18 case-insensitive file-systems (such as Mac OS).
    19 
    20   - The main Isabelle tool wrapper is now called "isabelle" instead of
    21     "isatool."
    22 
    23   - The former "isabelle" alias for "isabelle-process" has been
    24     removed (should rarely occur to regular users).
    25 
    26   - The former "isabelle-interface" and its alias "Isabelle" have been
    27     removed (interfaces are now regular Isabelle tools).
    28 
    29 Within scripts and make files, the Isabelle environment variables
    30 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    31 respectively.  (The latter are still available as legacy feature.)
    32 
    33 The old isabelle-interface wrapper could react in confusing ways if
    34 the interface was uninstalled or changed otherwise.  Individual
    35 interface tool configuration is now more explicit, see also the
    36 Isabelle system manual.  In particular, Proof General is now available
    37 via "isabelle emacs".
    38 
    39 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    40 purge installed copies of Isabelle executables and re-run "isabelle
    41 install -p ...", or use symlinks.
    42 
    43 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    44 old ~/isabelle, which was slightly non-standard and apt to cause
    45 surprises on case-insensitive file-systems (such as Mac OS).
    46 
    47 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    48 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    49 care is required when using older releases of Isabelle.  Note that
    50 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    51 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
    52 
    53 * Proofs of fully specified statements are run in parallel on
    54 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
    55 a regular 4-core machine, if the initial heap space is made reasonably
    56 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
    57 
    58 * The main reference manuals ("isar-ref", "implementation", and
    59 "system") have been updated and extended.  Formally checked references
    60 as hyperlinks are now available uniformly.
    61 
    62 
    63 *** Pure ***
    64 
    65 * Complete re-implementation of locales.  INCOMPATIBILITY in several
    66 respects.  The most important changes are listed below.  See the
    67 Tutorial on Locales ("locales" manual) for details.
    68 
    69 - In locale expressions, instantiation replaces renaming.  Parameters
    70 must be declared in a for clause.  To aid compatibility with previous
    71 parameter inheritance, in locale declarations, parameters that are not
    72 'touched' (instantiation position "_" or omitted) are implicitly added
    73 with their syntax at the beginning of the for clause.
    74 
    75 - Syntax from abbreviations and definitions in locales is available in
    76 locale expressions and context elements.  The latter is particularly
    77 useful in locale declarations.
    78 
    79 - More flexible mechanisms to qualify names generated by locale
    80 expressions.  Qualifiers (prefixes) may be specified in locale
    81 expressions, and can be marked as mandatory (syntax: "name!:") or
    82 optional (syntax "name?:").  The default depends for plain "name:"
    83 depends on the situation where a locale expression is used: in
    84 commands 'locale' and 'sublocale' prefixes are optional, in
    85 'interpretation' and 'interpret' prefixes are mandatory.  The old
    86 implicit qualifiers derived from the parameter names of a locale are
    87 no longer generated.
    88 
    89 - Command "sublocale l < e" replaces "interpretation l < e".  The
    90 instantiation clause in "interpretation" and "interpret" (square
    91 brackets) is no longer available.  Use locale expressions.
    92 
    93 - When converting proof scripts, mandatory qualifiers in
    94 'interpretation' and 'interpret' should be retained by default, even
    95 if this is an INCOMPATIBILITY compared to former behavior.  In the
    96 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
    97 in locale expressions range over a single locale instance only.
    98 
    99 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   100 In existing theorem specifications replace the includes element by the
   101 respective context elements of the included locale, omitting those
   102 that are already present in the theorem specification.  Multiple
   103 assume elements of a locale should be replaced by a single one
   104 involving the locale predicate.  In the proof body, declarations (most
   105 notably theorems) may be regained by interpreting the respective
   106 locales in the proof context as required (command "interpret").
   107 
   108 If using "includes" in replacement of a target solely because the
   109 parameter types in the theorem are not as general as in the target,
   110 consider declaring a new locale with additional type constraints on
   111 the parameters (context element "constrains").
   112 
   113 - Discontinued "locale (open)".  INCOMPATIBILITY.
   114 
   115 - Locale interpretation commands no longer attempt to simplify goal.
   116 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   117 methods intro_locales and unfold_locales to clarify.
   118 
   119 - Locale interpretation commands no longer accept interpretation
   120 attributes.  INCOMPATIBILITY.
   121 
   122 * Class declaration: so-called "base sort" must not be given in import
   123 list any longer, but is inferred from the specification.  Particularly
   124 in HOL, write
   125 
   126     class foo = ...
   127 
   128 instead of
   129 
   130     class foo = type + ...
   131 
   132 * Class target: global versions of theorems stemming do not carry a
   133 parameter prefix any longer.  INCOMPATIBILITY.
   134 
   135 * Class 'instance' command no longer accepts attached definitions.
   136 INCOMPATIBILITY, use proper 'instantiation' target instead.
   137 
   138 * Recovered hiding of consts, which was accidentally broken in
   139 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   140 makes c inaccessible; consider using ``hide (open) const c'' instead.
   141 
   142 * Slightly more coherent Pure syntax, with updated documentation in
   143 isar-ref manual.  Removed locales meta_term_syntax and
   144 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   145 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   146 directly in regular applications.
   147 
   148 * There is a new syntactic category "float_const" for signed decimal
   149 fractions (e.g. 123.45 or -123.45).
   150 
   151 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   152 interface with 'setup' command instead.
   153 
   154 * Command 'local_setup' is similar to 'setup', but operates on a local
   155 theory context.
   156 
   157 * The 'axiomatization' command now only works within a global theory
   158 context.  INCOMPATIBILITY.
   159 
   160 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   161 hypotheses.  Sorts required in the course of reasoning need to be
   162 covered by the constraints in the initial statement, completed by the
   163 type instance information of the background theory.  Non-trivial sort
   164 hypotheses, which rarely occur in practice, may be specified via
   165 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   166 
   167   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   168 
   169 The result contains an implicit sort hypotheses as before --
   170 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   171 normalization.
   172 
   173 * Generalized Isar history, with support for linear undo, direct state
   174 addressing etc.
   175 
   176 * Changed defaults for unify configuration options:
   177 
   178   unify_trace_bound = 50 (formerly 25)
   179   unify_search_bound = 60 (formerly 30)
   180 
   181 * Different bookkeeping for code equations (INCOMPATIBILITY):
   182 
   183   a) On theory merge, the last set of code equations for a particular
   184      constant is taken (in accordance with the policy applied by other
   185      parts of the code generator framework).
   186 
   187   b) Code equations stemming from explicit declarations (e.g. code
   188      attribute) gain priority over default code equations stemming
   189      from definition, primrec, fun etc.
   190 
   191 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   192 
   193 * Unified theorem tables for both code code generators.  Thus [code
   194 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   195 
   196 * Command 'find_consts' searches for constants based on type and name
   197 patterns, e.g.
   198 
   199     find_consts "_ => bool"
   200 
   201 By default, matching is against subtypes, but it may be restricted to
   202 the whole type.  Searching by name is possible.  Multiple queries are
   203 conjunctive and queries may be negated by prefixing them with a
   204 hyphen:
   205 
   206     find_consts strict: "_ => bool" name: "Int" -"int => int"
   207 
   208 * New 'find_theorems' criterion "solves" matches theorems that
   209 directly solve the current goal (modulo higher-order unification).
   210 
   211 * Auto solve feature for main theorem statements: whenever a new goal
   212 is stated, "find_theorems solves" is called; any theorems that could
   213 solve the lemma directly are listed as part of the goal state.
   214 Cf. associated options in Proof General Isabelle settings menu,
   215 enabled by default, with reasonable timeout for pathological cases of
   216 higher-order unification.
   217 
   218 
   219 *** Document preparation ***
   220 
   221 * Antiquotation @{lemma} now imitates a regular terminal proof,
   222 demanding keyword 'by' and supporting the full method expression
   223 syntax just like the Isar command 'by'.
   224 
   225 
   226 *** HOL ***
   227 
   228 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   229 points Main and Complex_Main remain as before.
   230 
   231 * Logic image HOL-Plain provides a minimal HOL with the most important
   232 tools available (inductive, datatype, primrec, ...).  This facilitates
   233 experimentation and tool development.  Note that user applications
   234 (and library theories) should never refer to anything below theory
   235 Main, as before.
   236 
   237 * Logic image HOL-Main stops at theory Main, and thus facilitates
   238 experimentation due to shorter build times.
   239 
   240 * Logic image HOL-NSA contains theories of nonstandard analysis which
   241 were previously part of former HOL-Complex.  Entry point Hyperreal
   242 remains valid, but theories formerly using Complex_Main should now use
   243 new entry point Hypercomplex.
   244 
   245 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   246 Posix processes.  Avoids potentially expensive forking of the ML
   247 process.  New thread-based implementation also works on non-Unix
   248 platforms (Cygwin).  Provers are no longer hardwired, but defined
   249 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   250 commands are covered in the isar-ref manual.
   251 
   252 * Wrapper scripts for remote SystemOnTPTP service allows to use
   253 sledgehammer without local ATP installation (Vampire etc.). Other
   254 provers may be included via suitable ML wrappers, see also
   255 src/HOL/ATP_Linkup.thy.
   256 
   257 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   258 menu.
   259 
   260 * The metis method no longer fails because the theorem is too trivial
   261 (contains the empty clause).
   262 
   263 * The metis method now fails in the usual manner, rather than raising
   264 an exception, if it determines that it cannot prove the theorem.
   265 
   266 * Method "coherent" implements a prover for coherent logic (see also
   267 src/Tools/coherent.ML).
   268 
   269 * Constants "undefined" and "default" replace "arbitrary".  Usually
   270 "undefined" is the right choice to replace "arbitrary", though
   271 logically there is no difference.  INCOMPATIBILITY.
   272 
   273 * Command "value" now integrates different evaluation mechanisms.  The
   274 result of the first successful evaluation mechanism is printed.  In
   275 square brackets a particular named evaluation mechanisms may be
   276 specified (currently, [SML], [code] or [nbe]).  See further
   277 src/HOL/ex/Eval_Examples.thy.
   278 
   279 * Normalization by evaluation now allows non-leftlinear equations.
   280 Declare with attribute [code nbe].
   281 
   282 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   283 as the structured Isar versions "cases" and "induct", cf. the
   284 corresponding "cases" and "induct" attributes.  Mutual induction rules
   285 are now presented as a list of individual projections
   286 (e.g. foo_bar.inducts for types foo and bar); the old format with
   287 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   288 rare situations a different rule is selected --- notably nested tuple
   289 elimination instead of former prod.exhaust: use explicit (case_tac t
   290 rule: prod.exhaust) here.
   291 
   292 * Attributes "cases", "induct", "coinduct" support "del" option.
   293 
   294 * Removed fact "case_split_thm", which duplicates "case_split".
   295 
   296 * The option datatype has been moved to a new theory Option.  Renamed
   297 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   298 
   299 * New predicate "strict_mono" classifies strict functions on partial
   300 orders.  With strict functions on linear orders, reasoning about
   301 (in)equalities is facilitated by theorems "strict_mono_eq",
   302 "strict_mono_less_eq" and "strict_mono_less".
   303 
   304 * Some set operations are now proper qualified constants with
   305 authentic syntax.  INCOMPATIBILITY:
   306 
   307     op Int ~>   Set.Int
   308     op Un ~>    Set.Un
   309     INTER ~>    Set.INTER
   310     UNION ~>    Set.UNION
   311     Inter ~>    Set.Inter
   312     Union ~>    Set.Union
   313     {} ~>       Set.empty
   314     UNIV ~>     Set.UNIV
   315 
   316 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   317 theory Set.
   318 
   319 * Auxiliary class "itself" has disappeared -- classes without any
   320 parameter are treated as expected by the 'class' command.
   321 
   322 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   323 
   324 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   325 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   326 
   327 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   328 method "approximation".  It proves formulas on real values by using
   329 interval arithmetic.  In the formulas are also the transcendental
   330 functions sin, cos, tan, atan, ln, exp and the constant pi are
   331 allowed. For examples see
   332 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   333 
   334 * Theory "Reflection" now resides in HOL/Library.
   335 
   336 * Entry point to Word library now simply named "Word".
   337 INCOMPATIBILITY.
   338 
   339 * Made source layout more coherent with logical distribution
   340 structure:
   341 
   342     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   343     src/HOL/Library/Code_Message.thy ~> src/HOL/
   344     src/HOL/Library/GCD.thy ~> src/HOL/
   345     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   346     src/HOL/Library/Parity.thy ~> src/HOL/
   347     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   348     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   349     src/HOL/Real/Lubs.thy ~> src/HOL/
   350     src/HOL/Real/PReal.thy ~> src/HOL/
   351     src/HOL/Real/Rational.thy ~> src/HOL/
   352     src/HOL/Real/RComplete.thy ~> src/HOL/
   353     src/HOL/Real/RealDef.thy ~> src/HOL/
   354     src/HOL/Real/RealPow.thy ~> src/HOL/
   355     src/HOL/Real/Real.thy ~> src/HOL/
   356     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   357     src/HOL/Complex/Complex.thy ~> src/HOL/
   358     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   359     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   360     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   361     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   362     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   363     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   364     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   365     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   366     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   367     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   368     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   369     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   370     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   371     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   372     src/HOL/Real/Float ~> src/HOL/Library/
   373     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   374     src/HOL/Real/RealVector.thy ~> src/HOL/
   375 
   376     src/HOL/arith_data.ML ~> src/HOL/Tools
   377     src/HOL/hologic.ML ~> src/HOL/Tools
   378     src/HOL/simpdata.ML ~> src/HOL/Tools
   379     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   380     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   381     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   382     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   383     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   384     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   385     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   386 
   387     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   388     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   389     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   390     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   391     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   392     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   393 
   394 * If methods "eval" and "evaluation" encounter a structured proof
   395 state with !!/==>, only the conclusion is evaluated to True (if
   396 possible), avoiding strange error messages.
   397 
   398 * Method "sizechange" automates termination proofs using (a
   399 modification of) the size-change principle.  Requires SAT solver.  See
   400 src/HOL/ex/Termination.thy for examples.
   401 
   402 * Simplifier: simproc for let expressions now unfolds if bound
   403 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   404 
   405 * Method "arith": Linear arithmetic now ignores all inequalities when
   406 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   407 
   408 * New attribute "arith" for facts that should always be used
   409 automatically by arithmetic. It is intended to be used locally in
   410 proofs, e.g.
   411 
   412   assumes [arith]: "x > 0"
   413 
   414 Global usage is discouraged because of possible performance impact.
   415 
   416 * New classes "top" and "bot" with corresponding operations "top" and
   417 "bot" in theory Orderings; instantiation of class "complete_lattice"
   418 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   419 
   420 * Changed definition lemma "less_fun_def" in order to provide an
   421 instance for preorders on functions; use lemma "less_le" instead.
   422 INCOMPATIBILITY.
   423 
   424 * Theory Orderings: class "wellorder" moved here, with explicit
   425 induction rule "less_induct" as assumption.  For instantiation of
   426 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   427 INCOMPATIBILITY.
   428 
   429 * Theory Orderings: added class "preorder" as superclass of "order".
   430 INCOMPATIBILITY: Instantiation proofs for order, linorder
   431 etc. slightly changed.  Some theorems named order_class.* now named
   432 preorder_class.*.
   433 
   434 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   435 "diag" to "Id_on".
   436 
   437 * Theory Finite_Set: added a new fold combinator of type
   438 
   439   ('a => 'b => 'b) => 'b => 'a set => 'b
   440 
   441 Occasionally this is more convenient than the old fold combinator
   442 which is now defined in terms of the new one and renamed to
   443 fold_image.
   444 
   445 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   446 and "ring_simps" have been replaced by "algebra_simps" (which can be
   447 extended with further lemmas!).  At the moment both still exist but
   448 the former will disappear at some point.
   449 
   450 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   451 class recpower.  Type-specific simp rules for various recpower types
   452 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   453 
   454 rat_power_0    -> power_0
   455 rat_power_Suc  -> power_Suc
   456 realpow_0      -> power_0
   457 realpow_Suc    -> power_Suc
   458 complexpow_0   -> power_0
   459 complexpow_Suc -> power_Suc
   460 power_poly_0   -> power_0
   461 power_poly_Suc -> power_Suc
   462 
   463 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   464 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   465 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   466 of lemmas from Divides has been generalized from nat to class
   467 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   468 renames resulting from duplicate elimination:
   469 
   470     dvd_def_mod ~>          dvd_eq_mod_eq_0
   471     zero_dvd_iff ~>         dvd_0_left_iff
   472     dvd_0 ~>                dvd_0_right
   473     DIVISION_BY_ZERO_DIV ~> div_by_0
   474     DIVISION_BY_ZERO_MOD ~> mod_by_0
   475     mult_div ~>             div_mult_self2_is_id
   476     mult_mod ~>             mod_mult_self2_is_0
   477 
   478 * Theory IntDiv: removed many lemmas that are instances of class-based
   479 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   480 rename old lemmas as follows:
   481 
   482 dvd_diff               -> nat_dvd_diff
   483 dvd_zminus_iff         -> dvd_minus_iff
   484 mod_add1_eq            -> mod_add_eq
   485 mod_mult1_eq           -> mod_mult_right_eq
   486 mod_mult1_eq'          -> mod_mult_left_eq
   487 mod_mult_distrib_mod   -> mod_mult_eq
   488 nat_mod_add_left_eq    -> mod_add_left_eq
   489 nat_mod_add_right_eq   -> mod_add_right_eq
   490 nat_mod_div_trivial    -> mod_div_trivial
   491 nat_mod_mod_trivial    -> mod_mod_trivial
   492 zdiv_zadd_self1        -> div_add_self1
   493 zdiv_zadd_self2        -> div_add_self2
   494 zdiv_zmult_self1       -> div_mult_self2_is_id
   495 zdiv_zmult_self2       -> div_mult_self1_is_id
   496 zdvd_triv_left         -> dvd_triv_left
   497 zdvd_triv_right        -> dvd_triv_right
   498 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   499 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   500 zmod_zadd_left_eq      -> mod_add_left_eq
   501 zmod_zadd_right_eq     -> mod_add_right_eq
   502 zmod_zadd_self1        -> mod_add_self1
   503 zmod_zadd_self2        -> mod_add_self2
   504 zmod_zadd1_eq          -> mod_add_eq
   505 zmod_zdiff1_eq         -> mod_diff_eq
   506 zmod_zdvd_zmod         -> mod_mod_cancel
   507 zmod_zmod_cancel       -> mod_mod_cancel
   508 zmod_zmult_self1       -> mod_mult_self2_is_0
   509 zmod_zmult_self2       -> mod_mult_self1_is_0
   510 zmod_1                 -> mod_by_1
   511 zdiv_1                 -> div_by_1
   512 zdvd_abs1              -> abs_dvd_iff
   513 zdvd_abs2              -> dvd_abs_iff
   514 zdvd_refl              -> dvd_refl
   515 zdvd_trans             -> dvd_trans
   516 zdvd_zadd              -> dvd_add
   517 zdvd_zdiff             -> dvd_diff
   518 zdvd_zminus_iff        -> dvd_minus_iff
   519 zdvd_zminus2_iff       -> minus_dvd_iff
   520 zdvd_zmultD            -> dvd_mult_right
   521 zdvd_zmultD2           -> dvd_mult_left
   522 zdvd_zmult_mono        -> mult_dvd_mono
   523 zdvd_0_right           -> dvd_0_right
   524 zdvd_0_left            -> dvd_0_left_iff
   525 zdvd_1_left            -> one_dvd
   526 zminus_dvd_iff         -> minus_dvd_iff
   527 
   528 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   529 
   530 * The real numbers offer decimal input syntax: 12.34 is translated
   531 into 1234/10^2. This translation is not reversed upon output.
   532 
   533 * Theory Library/Polynomial defines an abstract type 'a poly of
   534 univariate polynomials with coefficients of type 'a.  In addition to
   535 the standard ring operations, it also supports div and mod.  Code
   536 generation is also supported, using list-style constructors.
   537 
   538 * Theory Library/Inner_Product defines a class of real_inner for real
   539 inner product spaces, with an overloaded operation inner :: 'a => 'a
   540 => real.  Class real_inner is a subclass of real_normed_vector from
   541 theory RealVector.
   542 
   543 * Theory Library/Product_Vector provides instances for the product
   544 type 'a * 'b of several classes from RealVector and Inner_Product.
   545 Definitions of addition, subtraction, scalar multiplication, norms,
   546 and inner products are included.
   547 
   548 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   549 addition to the field operations, numerals and case syntax are also
   550 supported.
   551 
   552 * Theory Library/Diagonalize provides constructive version of Cantor's
   553 first diagonalization argument.
   554 
   555 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   556 zlcm (for int); carried together from various gcd/lcm developements in
   557 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   558 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   559 may recover tupled syntax as follows:
   560 
   561     hide (open) const gcd
   562     abbreviation gcd where
   563       "gcd == (%(a, b). GCD.gcd a b)"
   564     notation (output)
   565       GCD.gcd ("gcd '(_, _')")
   566 
   567 The same works for lcm, zgcd, zlcm.
   568 
   569 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   570 instantiations for algebraic structures.  Removed some duplicate
   571 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   572 
   573 * ML antiquotation @{code} takes a constant as argument and generates
   574 corresponding code in background and inserts name of the corresponding
   575 resulting ML value/function/datatype constructor binding in place.
   576 All occurrences of @{code} with a single ML block are generated
   577 simultaneously.  Provides a generic and safe interface for
   578 instrumentalizing code generation.  See
   579 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   580 In future you ought to refrain from ad-hoc compiling generated SML
   581 code on the ML toplevel.  Note that (for technical reasons) @{code}
   582 cannot refer to constants for which user-defined serializations are
   583 set.  Refer to the corresponding ML counterpart directly in that
   584 cases.
   585 
   586 * Command 'rep_datatype': instead of theorem names the command now
   587 takes a list of terms denoting the constructors of the type to be
   588 represented as datatype.  The characteristic theorems have to be
   589 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   590 have disappeared in favour of existing ones:
   591 
   592     unit_induct                 ~> unit.induct
   593     prod_induct                 ~> prod.induct
   594     sum_induct                  ~> sum.induct
   595     Suc_Suc_eq                  ~> nat.inject
   596     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   597 
   598 
   599 *** HOL-Algebra ***
   600 
   601 * New locales for orders and lattices where the equivalence relation
   602 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   603 locales use a record structure with field eq for the equivalence.
   604 
   605 * New theory of factorial domains.
   606 
   607 * Units_l_inv and Units_r_inv are now simp rules by default.
   608 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   609 and/or r_inv will now also require deletion of these lemmas.
   610 
   611 * Renamed the following theorems, INCOMPATIBILITY:
   612 
   613 UpperD ~> Upper_memD
   614 LowerD ~> Lower_memD
   615 least_carrier ~> least_closed
   616 greatest_carrier ~> greatest_closed
   617 greatest_Lower_above ~> greatest_Lower_below
   618 one_zero ~> carrier_one_zero
   619 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   620 
   621 
   622 *** HOL-Nominal ***
   623 
   624 * Nominal datatypes can now contain type-variables.
   625 
   626 * Commands 'nominal_inductive' and 'equivariance' work with local
   627 theory targets.
   628 
   629 * Nominal primrec can now works with local theory targets and its
   630 specification syntax now conforms to the general format as seen in
   631 'inductive' etc.
   632 
   633 * Method "perm_simp" honours the standard simplifier attributes
   634 (no_asm), (no_asm_use) etc.
   635 
   636 * The new predicate #* is defined like freshness, except that on the
   637 left hand side can be a set or list of atoms.
   638 
   639 * Experimental command 'nominal_inductive2' derives strong induction
   640 principles for inductive definitions.  In contrast to
   641 'nominal_inductive', which can only deal with a fixed number of
   642 binders, it can deal with arbitrary expressions standing for sets of
   643 atoms to be avoided.  The only inductive definition we have at the
   644 moment that needs this generalisation is the typing rule for Lets in
   645 the algorithm W:
   646 
   647  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   648  -----------------------------------------------------------------
   649          Gamma |- Let x be t1 in t2 : T2
   650 
   651 In this rule one wants to avoid all the binders that are introduced by
   652 "close Gamma T1".  We are looking for other examples where this
   653 feature might be useful.  Please let us know.
   654 
   655 
   656 *** HOLCF ***
   657 
   658 * Reimplemented the simplification procedure for proving continuity
   659 subgoals.  The new simproc is extensible; users can declare additional
   660 continuity introduction rules with the attribute [cont2cont].
   661 
   662 * The continuity simproc now uses a different introduction rule for
   663 solving continuity subgoals on terms with lambda abstractions.  In
   664 some rare cases the new simproc may fail to solve subgoals that the
   665 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   666 Potential INCOMPATIBILITY.
   667 
   668 * Command 'fixrec': specification syntax now conforms to the general
   669 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   670 examples.  INCOMPATIBILITY.
   671 
   672 
   673 *** ZF ***
   674 
   675 * Proof of Zorn's Lemma for partial orders.
   676 
   677 
   678 *** ML ***
   679 
   680 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   681 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   682 depends on multithreading, so timouts will not work before Poly/ML
   683 5.2.1!
   684 
   685 * High-level support for concurrent ML programming, see
   686 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   687 particularly convenient to organize independent functional
   688 computations.  The concept of "synchronized variables" provides a
   689 higher-order interface for components with shared state, avoiding the
   690 delicate details of mutexes and condition variables.  (Requires
   691 Poly/ML 5.2.1 or later.)
   692 
   693 * ML bindings produced via Isar commands are stored within the Isar
   694 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   695 become thread-safe and work with undo as expected (concerning
   696 top-level bindings, not side-effects on global references).
   697 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   698 compiler at runtime; really global bindings need to be given outside a
   699 theory.  (Requires Poly/ML 5.2 or later.)
   700 
   701 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   702 context.  Top-level ML bindings are stored within the proof context in
   703 a purely sequential fashion, disregarding the nested proof structure.
   704 ML bindings introduced by 'ML_prf' are discarded at the end of the
   705 proof.  (Requires Poly/ML 5.2 or later.)
   706 
   707 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   708 and Method.setup, as well as Isar commands 'attribute_setup' and
   709 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   710 existing code accordingly, or use plain 'setup' together with old
   711 Method.add_method.
   712 
   713 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   714 to 'a -> thm, while results are always tagged with an authentic oracle
   715 name.  The Isar command 'oracle' is now polymorphic, no argument type
   716 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   717 accordingly.  Note that extra performance may be gained by producing
   718 the cterm carefully, avoiding slow Thm.cterm_of.
   719 
   720 * Simplified interface for defining document antiquotations via
   721 ThyOutput.antiquotation, ThyOutput.output, and optionally
   722 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   723 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   724 examples.
   725 
   726 * More systematic treatment of long names, abstract name bindings, and
   727 name space operations.  Basic operations on qualified names have been
   728 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   729 Long_Name.append.  Old type bstring has been mostly replaced by
   730 abstract type binding (see structure Binding), which supports precise
   731 qualification by packages and local theory targets, as well as proper
   732 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   733 bstring values into Binding.name, or better pass through abstract
   734 bindings everywhere.  See further src/Pure/General/long_name.ML,
   735 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   736 
   737 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   738 LocalTheory.note etc.) now refer to the *full* internal name, not the
   739 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   740 
   741 * Disposed old type and term read functions (Sign.read_def_typ,
   742 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   743 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   744 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   745 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   746 resort for legacy applications.
   747 
   748 * Disposed old declarations, tactics, tactic combinators that refer to
   749 the simpset or claset of an implicit theory (such as Addsimps,
   750 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   751 embedded ML text, or local_simpset_of with a proper context passed as
   752 explicit runtime argument.
   753 
   754 * Rules and tactics that read instantiations (read_instantiate,
   755 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   756 context, which is required for parsing and type-checking.  Moreover,
   757 the variables are specified as plain indexnames, not string encodings
   758 thereof.  INCOMPATIBILITY.
   759 
   760 * Generic Toplevel.add_hook interface allows to analyze the result of
   761 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   762 for theorem dependency output of transactions resulting in a new
   763 theory state.
   764 
   765 * ML antiquotations: block-structured compilation context indicated by
   766 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   767 
   768   @{binding name}                         - basic name binding
   769   @{let ?pat = term}                      - term abbreviation (HO matching)
   770   @{note name = fact}                     - fact abbreviation
   771   @{thm fact}                             - singleton fact (with attributes)
   772   @{thms fact}                            - general fact (with attributes)
   773   @{lemma prop by method}                 - singleton goal
   774   @{lemma prop by meth1 meth2}            - singleton goal
   775   @{lemma prop1 ... propN by method}      - general goal
   776   @{lemma prop1 ... propN by meth1 meth2} - general goal
   777   @{lemma (open) ...}                     - open derivation
   778 
   779 
   780 *** System ***
   781 
   782 * The Isabelle "emacs" tool provides a specific interface to invoke
   783 Proof General / Emacs, with more explicit failure if that is not
   784 installed (the old isabelle-interface script silently falls back on
   785 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   786 installation location of the Proof General distribution.
   787 
   788 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   789 the Isabelle process into a JVM/Scala application.  See
   790 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   791 process wrapper has been discontinued.)
   792 
   793 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   794 
   795 * Various status messages (with exact source position information) are
   796 emitted, if proper markup print mode is enabled.  This allows
   797 user-interface components to provide detailed feedback on internal
   798 prover operations.
   799 
   800 
   801 
   802 New in Isabelle2008 (June 2008)
   803 -------------------------------
   804 
   805 *** General ***
   806 
   807 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   808 and updated, with formally checked references as hyperlinks.
   809 
   810 * Theory loader: use_thy (and similar operations) no longer set the
   811 implicit ML context, which was occasionally hard to predict and in
   812 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   813 provides a proper context already.
   814 
   815 * Theory loader: old-style ML proof scripts being *attached* to a thy
   816 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   817 'use' within a theory file will do the job.
   818 
   819 * Name space merge now observes canonical order, i.e. the second space
   820 is inserted into the first one, while existing entries in the first
   821 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   822 swap theory imports.
   823 
   824 * Syntax: symbol \<chi> is now considered a letter.  Potential
   825 INCOMPATIBILITY in identifier syntax etc.
   826 
   827 * Outer syntax: string tokens no longer admit escaped white space,
   828 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   829 white space without escapes.
   830 
   831 * Outer syntax: string tokens may contain arbitrary character codes
   832 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   833 "foo_bar".
   834 
   835 
   836 *** Pure ***
   837 
   838 * Context-dependent token translations.  Default setup reverts locally
   839 fixed variables, and adds hilite markup for undeclared frees.
   840 
   841 * Unused theorems can be found using the new command 'unused_thms'.
   842 There are three ways of invoking it:
   843 
   844 (1) unused_thms
   845      Only finds unused theorems in the current theory.
   846 
   847 (2) unused_thms thy_1 ... thy_n -
   848      Finds unused theorems in the current theory and all of its ancestors,
   849      excluding the theories thy_1 ... thy_n and all of their ancestors.
   850 
   851 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   852      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   853      their ancestors, excluding the theories thy_1 ... thy_n and all of
   854      their ancestors.
   855 
   856 In order to increase the readability of the list produced by
   857 unused_thms, theorems that have been created by a particular instance
   858 of a theory command such as 'inductive' or 'function' are considered
   859 to belong to the same "group", meaning that if at least one theorem in
   860 this group is used, the other theorems in the same group are no longer
   861 reported as unused.  Moreover, if all theorems in the group are
   862 unused, only one theorem in the group is displayed.
   863 
   864 Note that proof objects have to be switched on in order for
   865 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   866 usually the case when using Proof General with the default settings).
   867 
   868 * Authentic naming of facts disallows ad-hoc overwriting of previous
   869 theorems within the same name space.  INCOMPATIBILITY, need to remove
   870 duplicate fact bindings, or even accidental fact duplications.  Note
   871 that tools may maintain dynamically scoped facts systematically, using
   872 PureThy.add_thms_dynamic.
   873 
   874 * Command 'hide' now allows to hide from "fact" name space as well.
   875 
   876 * Eliminated destructive theorem database, simpset, claset, and
   877 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   878 update of theories within ML code.
   879 
   880 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   881 INCOMPATIBILITY, object-logics depending on former Pure require
   882 additional setup PureThy.old_appl_syntax_setup; object-logics
   883 depending on former CPure need to refer to Pure.
   884 
   885 * Commands 'use' and 'ML' are now purely functional, operating on
   886 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   887 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   888 INCOMPATIBILITY.
   889 
   890 * Command 'setup': discontinued implicit version with ML reference.
   891 
   892 * Instantiation target allows for simultaneous specification of class
   893 instance operations together with an instantiation proof.
   894 Type-checking phase allows to refer to class operations uniformly.
   895 See src/HOL/Complex/Complex.thy for an Isar example and
   896 src/HOL/Library/Eval.thy for an ML example.
   897 
   898 * Indexing of literal facts: be more serious about including only
   899 facts from the visible specification/proof context, but not the
   900 background context (locale etc.).  Affects `prop` notation and method
   901 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   902 situations.
   903 
   904 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   905 "(open)" option, which used to expose internal bound variables to the
   906 proof text.
   907 
   908 * Isar statements: removed obsolete case "rule_context".
   909 INCOMPATIBILITY, better use explicit fixes/assumes.
   910 
   911 * Locale proofs: default proof step now includes 'unfold_locales';
   912 hence 'proof' without argument may be used to unfold locale
   913 predicates.
   914 
   915 
   916 *** Document preparation ***
   917 
   918 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   919 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   920 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   921 spot); renamed link color from "darkblue" to "linkcolor" (default
   922 value unchanged, can be redefined via \definecolor); no longer sets
   923 "a4paper" option (unnecessary or even intrusive).
   924 
   925 * Antiquotation @{lemma A method} proves proposition A by the given
   926 method (either a method name or a method name plus (optional) method
   927 arguments in parentheses) and prints A just like @{prop A}.
   928 
   929 
   930 *** HOL ***
   931 
   932 * New primrec package.  Specification syntax conforms in style to
   933 definition/function/....  No separate induction rule is provided.  The
   934 "primrec" command distinguishes old-style and new-style specifications
   935 by syntax.  The former primrec package is now named OldPrimrecPackage.
   936 When adjusting theories, beware: constants stemming from new-style
   937 primrec specifications have authentic syntax.
   938 
   939 * Metis prover is now an order of magnitude faster, and also works
   940 with multithreading.
   941 
   942 * Metis: the maximum number of clauses that can be produced from a
   943 theorem is now given by the attribute max_clauses.  Theorems that
   944 exceed this number are ignored, with a warning printed.
   945 
   946 * Sledgehammer no longer produces structured proofs by default. To
   947 enable, declare [[sledgehammer_full = true]].  Attributes
   948 reconstruction_modulus, reconstruction_sorts renamed
   949 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   950 
   951 * Method "induct_scheme" derives user-specified induction rules
   952 from well-founded induction and completeness of patterns. This factors
   953 out some operations that are done internally by the function package
   954 and makes them available separately.  See
   955 src/HOL/ex/Induction_Scheme.thy for examples.
   956 
   957 * More flexible generation of measure functions for termination
   958 proofs: Measure functions can be declared by proving a rule of the
   959 form "is_measure f" and giving it the [measure_function] attribute.
   960 The "is_measure" predicate is logically meaningless (always true), and
   961 just guides the heuristic.  To find suitable measure functions, the
   962 termination prover sets up the goal "is_measure ?f" of the appropriate
   963 type and generates all solutions by prolog-style backwards proof using
   964 the declared rules.
   965 
   966 This setup also deals with rules like 
   967 
   968   "is_measure f ==> is_measure (list_size f)"
   969 
   970 which accommodates nested datatypes that recurse through lists.
   971 Similar rules are predeclared for products and option types.
   972 
   973 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   974 
   975   INCOMPATIBILITIES:
   976 
   977   - Definitions of overloaded constants on sets have to be replaced by
   978     definitions on => and bool.
   979 
   980   - Some definitions of overloaded operators on sets can now be proved
   981     using the definitions of the operators on => and bool.  Therefore,
   982     the following theorems have been renamed:
   983 
   984       subset_def   -> subset_eq
   985       psubset_def  -> psubset_eq
   986       set_diff_def -> set_diff_eq
   987       Compl_def    -> Compl_eq
   988       Sup_set_def  -> Sup_set_eq
   989       Inf_set_def  -> Inf_set_eq
   990       sup_set_def  -> sup_set_eq
   991       inf_set_def  -> inf_set_eq
   992 
   993   - Due to the incompleteness of the HO unification algorithm, some
   994     rules such as subst may require manual instantiation, if some of
   995     the unknowns in the rule is a set.
   996 
   997   - Higher order unification and forward proofs:
   998     The proof pattern
   999 
  1000       have "P (S::'a set)" <...>
  1001       then have "EX S. P S" ..
  1002 
  1003     no longer works (due to the incompleteness of the HO unification
  1004     algorithm) and must be replaced by the pattern
  1005 
  1006       have "EX S. P S"
  1007       proof
  1008         show "P S" <...>
  1009       qed
  1010 
  1011   - Calculational reasoning with subst (or similar rules):
  1012     The proof pattern
  1013 
  1014       have "P (S::'a set)" <...>
  1015       also have "S = T" <...>
  1016       finally have "P T" .
  1017 
  1018     no longer works (for similar reasons as the previous example) and
  1019     must be replaced by something like
  1020 
  1021       have "P (S::'a set)" <...>
  1022       moreover have "S = T" <...>
  1023       ultimately have "P T" by simp
  1024 
  1025   - Tactics or packages written in ML code:
  1026     Code performing pattern matching on types via
  1027 
  1028       Type ("set", [T]) => ...
  1029 
  1030     must be rewritten. Moreover, functions like strip_type or
  1031     binder_types no longer return the right value when applied to a
  1032     type of the form
  1033 
  1034       T1 => ... => Tn => U => bool
  1035 
  1036     rather than
  1037 
  1038       T1 => ... => Tn => U set
  1039 
  1040 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1041 Wellfounded_Relations to theory Wellfounded.
  1042 
  1043 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1044 
  1045 * Class finite no longer treats UNIV as class parameter.  Use class
  1046 enum from theory Library/Enum instead to achieve a similar effect.
  1047 INCOMPATIBILITY.
  1048 
  1049 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1050 and "Cons".  INCOMPATIBILITY.
  1051 
  1052 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1053 Potential INCOMPATIBILITY.
  1054 
  1055 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1056 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1057 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1058 
  1059 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1060 the same name in theory Orderings:
  1061 
  1062   less_trans
  1063   less_linear
  1064   le_imp_less_or_eq
  1065   le_less_trans
  1066   less_le_trans
  1067   less_not_sym
  1068   less_asym
  1069 
  1070 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1071 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1072 and different variable names.
  1073 
  1074 * Library/Option_ord.thy: Canonical order on option type.
  1075 
  1076 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1077 finite maps.
  1078 
  1079 * Library/Countable.thy: Type class for countable types.
  1080 
  1081 * Theory Int: The representation of numerals has changed.  The infix
  1082 operator BIT and the bit datatype with constructors B0 and B1 have
  1083 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1084 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1085 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1086 accordingly.
  1087 
  1088 * Theory Nat: definition of <= and < on natural numbers no longer
  1089 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1090 le_def and less_def have disappeared.  Consider lemmas not_less
  1091 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1092 
  1093 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1094 (whose purpose mainly is for various fold_set functionals) have been
  1095 abandoned in favor of the existing algebraic classes
  1096 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1097 lower_semilattice (resp. upper_semilattice) and linorder.
  1098 INCOMPATIBILITY.
  1099 
  1100 * Theory Transitive_Closure: induct and cases rules now declare proper
  1101 case_names ("base" and "step").  INCOMPATIBILITY.
  1102 
  1103 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1104 lattices.  The form set-specific version is available as
  1105 Inductive.lfp_ordinal_induct_set.
  1106 
  1107 * Renamed theorems "power.simps" to "power_int.simps".
  1108 INCOMPATIBILITY.
  1109 
  1110 * Class semiring_div provides basic abstract properties of semirings
  1111 with division and modulo operations.  Subsumes former class dvd_mod.
  1112 
  1113 * Merged theories IntDef, Numeral and IntArith into unified theory
  1114 Int.  INCOMPATIBILITY.
  1115 
  1116 * Theory Library/Code_Index: type "index" now represents natural
  1117 numbers rather than integers.  INCOMPATIBILITY.
  1118 
  1119 * New class "uminus" with operation "uminus" (split of from class
  1120 "minus" which now only has operation "minus", binary).
  1121 INCOMPATIBILITY.
  1122 
  1123 * Constants "card", "internal_split", "option_map" now with authentic
  1124 syntax.  INCOMPATIBILITY.
  1125 
  1126 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1127 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1128 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1129 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1130 Sup_set_def, le_def, less_def, option_map_def now with object
  1131 equality.  INCOMPATIBILITY.
  1132 
  1133 * Records. Removed K_record, and replaced it by pure lambda term
  1134 %x. c. The simplifier setup is now more robust against eta expansion.
  1135 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1136 
  1137 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1138 
  1139 * Library/ListVector: new theory of arithmetic vector operations.
  1140 
  1141 * Library/Order_Relation: new theory of various orderings as sets of
  1142 pairs.  Defines preorders, partial orders, linear orders and
  1143 well-orders on sets and on types.
  1144 
  1145 
  1146 *** ZF ***
  1147 
  1148 * Renamed some theories to allow to loading both ZF and HOL in the
  1149 same session:
  1150 
  1151   Datatype  -> Datatype_ZF
  1152   Inductive -> Inductive_ZF
  1153   Int       -> Int_ZF
  1154   IntDiv    -> IntDiv_ZF
  1155   Nat       -> Nat_ZF
  1156   List      -> List_ZF
  1157   Main      -> Main_ZF
  1158 
  1159 INCOMPATIBILITY: ZF theories that import individual theories below
  1160 Main might need to be adapted.  Regular theory Main is still
  1161 available, as trivial extension of Main_ZF.
  1162 
  1163 
  1164 *** ML ***
  1165 
  1166 * ML within Isar: antiquotation @{const name} or @{const
  1167 name(typargs)} produces statically-checked Const term.
  1168 
  1169 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1170 (of the same name).  Removed obsolete print command.
  1171 
  1172 * Removed obsolete "use_legacy_bindings" function.
  1173 
  1174 * The ``print mode'' is now a thread-local value derived from a global
  1175 template (the former print_mode reference), thus access becomes
  1176 non-critical.  The global print_mode reference is for session
  1177 management only; user-code should use print_mode_value,
  1178 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1179 
  1180 * Functions system/system_out provide a robust way to invoke external
  1181 shell commands, with propagation of interrupts (requires Poly/ML
  1182 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1183 
  1184 
  1185 *** System ***
  1186 
  1187 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1188 in accordance with Proof General 3.7, which prefers GNU emacs.
  1189 
  1190 * isatool tty runs Isabelle process with plain tty interaction;
  1191 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1192 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1193 
  1194 * isatool browser now works with Cygwin as well, using general
  1195 "javapath" function defined in Isabelle process environment.
  1196 
  1197 * YXML notation provides a simple and efficient alternative to
  1198 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1199 isatool yxml as described in the Isabelle system manual.
  1200 
  1201 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1202 provides general wrapper for managing an Isabelle process in a robust
  1203 fashion, with ``cooked'' output from stdin/stderr.
  1204 
  1205 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1206 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1207 
  1208 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1209 way of changing the user's settings is via
  1210 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1211 script.
  1212 
  1213 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1214 cores of the underlying machine, which is a good starting point for
  1215 optimal performance tuning.  The corresponding usedir option -M allows
  1216 "max" as an alias for "0".  WARNING: does not work on certain versions
  1217 of Mac OS (with Poly/ML 5.1).
  1218 
  1219 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1220 adverse effect of Isabelle flooding interactive front-ends (notably
  1221 ProofGeneral / XEmacs).
  1222 
  1223 
  1224 
  1225 New in Isabelle2007 (November 2007)
  1226 -----------------------------------
  1227 
  1228 *** General ***
  1229 
  1230 * More uniform information about legacy features, notably a
  1231 warning/error of "Legacy feature: ...", depending on the state of the
  1232 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1233 legacy features will disappear eventually.
  1234 
  1235 * Theory syntax: the header format ``theory A = B + C:'' has been
  1236 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1237 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1238 
  1239 * Theory syntax: the old non-Isar theory file format has been
  1240 discontinued altogether.  Note that ML proof scripts may still be used
  1241 with Isar theories; migration is usually quite simple with the ML
  1242 function use_legacy_bindings.  INCOMPATIBILITY.
  1243 
  1244 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1245 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1246 quotes.
  1247 
  1248 * Theory loader: be more serious about observing the static theory
  1249 header specifications (including optional directories), but not the
  1250 accidental file locations of previously successful loads.  The strict
  1251 update policy of former update_thy is now already performed by
  1252 use_thy, so the former has been removed; use_thys updates several
  1253 theories simultaneously, just as 'imports' within a theory header
  1254 specification, but without merging the results.  Potential
  1255 INCOMPATIBILITY: may need to refine theory headers and commands
  1256 ROOT.ML which depend on load order.
  1257 
  1258 * Theory loader: optional support for content-based file
  1259 identification, instead of the traditional scheme of full physical
  1260 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1261 (cf. the system manual).  The new scheme allows to work with
  1262 non-finished theories in persistent session images, such that source
  1263 files may be moved later on without requiring reloads.
  1264 
  1265 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1266 file (with the same base name as the theory) are considered a legacy
  1267 feature, which will disappear eventually. Even now, the theory loader
  1268 no longer maintains dependencies on such files.
  1269 
  1270 * Syntax: the scope for resolving ambiguities via type-inference is
  1271 now limited to individual terms, instead of whole simultaneous
  1272 specifications as before. This greatly reduces the complexity of the
  1273 syntax module and improves flexibility by separating parsing and
  1274 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1275 'fixes' etc.) are required in rare situations.
  1276 
  1277 * Syntax: constants introduced by new-style packages ('definition',
  1278 'abbreviation' etc.) are passed through the syntax module in
  1279 ``authentic mode''. This means that associated mixfix annotations
  1280 really stick to such constants, independently of potential name space
  1281 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1282 trees are represented slightly differently, may need to adapt syntax
  1283 translations accordingly. Use CONST marker in 'translations' and
  1284 @{const_syntax} antiquotation in 'parse_translation' etc.
  1285 
  1286 * Legacy goal package: reduced interface to the bare minimum required
  1287 to keep existing proof scripts running.  Most other user-level
  1288 functions are now part of the OldGoals structure, which is *not* open
  1289 by default (consider isatool expandshort before open OldGoals).
  1290 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1291 these tend to cause confusion about the actual goal (!) context being
  1292 used here, which is not necessarily the same as the_context().
  1293 
  1294 * Command 'find_theorems': supports "*" wild-card in "name:"
  1295 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1296 support a specific search form (see ProofGeneral/CHANGES).
  1297 
  1298 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1299 by default, which means that "prems" (and also "fixed variables") are
  1300 suppressed from proof state output.  Note that the ProofGeneral
  1301 settings mechanism allows to change and save options persistently, but
  1302 older versions of Isabelle will fail to start up if a negative prems
  1303 limit is imposed.
  1304 
  1305 * Local theory targets may be specified by non-nested blocks of
  1306 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1307 contain definitions, theorems etc., including any derived mechanism
  1308 that has been implemented on top of these primitives.  This concept
  1309 generalizes the existing ``theorem (in ...)'' towards more versatility
  1310 and scalability.
  1311 
  1312 * Proof General interface: proper undo of final 'end' command;
  1313 discontinued Isabelle/classic mode (ML proof scripts).
  1314 
  1315 
  1316 *** Document preparation ***
  1317 
  1318 * Added antiquotation @{theory name} which prints the given name,
  1319 after checking that it refers to a valid ancestor theory in the
  1320 current context.
  1321 
  1322 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1323 check the given source text as ML type/structure, printing verbatim.
  1324 
  1325 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1326 "c args == rhs" given in the current context.  (Any number of
  1327 arguments may be given on the LHS.)
  1328 
  1329 
  1330 *** Pure ***
  1331 
  1332 * The 'class' package offers a combination of axclass and locale to
  1333 achieve Haskell-like type classes in Isabelle.  Definitions and
  1334 theorems within a class context produce both relative results (with
  1335 implicit parameters according to the locale context), and polymorphic
  1336 constants with qualified polymorphism (according to the class
  1337 context).  Within the body context of a 'class' target, a separate
  1338 syntax layer ("user space type system") takes care of converting
  1339 between global polymorphic consts and internal locale representation.
  1340 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1341 "isatool doc classes" provides a tutorial.
  1342 
  1343 * Generic code generator framework allows to generate executable
  1344 code for ML and Haskell (including Isabelle classes).  A short usage
  1345 sketch:
  1346 
  1347     internal compilation:
  1348         export_code <list of constants (term syntax)> in SML
  1349     writing SML code to a file:
  1350         export_code <list of constants (term syntax)> in SML <filename>
  1351     writing OCaml code to a file:
  1352         export_code <list of constants (term syntax)> in OCaml <filename>
  1353     writing Haskell code to a bunch of files:
  1354         export_code <list of constants (term syntax)> in Haskell <filename>
  1355 
  1356     evaluating closed propositions to True/False using code generation:
  1357         method ``eval''
  1358 
  1359 Reasonable default setup of framework in HOL.
  1360 
  1361 Theorem attributs for selecting and transforming function equations theorems:
  1362 
  1363     [code fun]:        select a theorem as function equation for a specific constant
  1364     [code fun del]:    deselect a theorem as function equation for a specific constant
  1365     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1366     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1367 
  1368 User-defined serializations (target in {SML, OCaml, Haskell}):
  1369 
  1370     code_const <and-list of constants (term syntax)>
  1371       {(target) <and-list of const target syntax>}+
  1372 
  1373     code_type <and-list of type constructors>
  1374       {(target) <and-list of type target syntax>}+
  1375 
  1376     code_instance <and-list of instances>
  1377       {(target)}+
  1378         where instance ::= <type constructor> :: <class>
  1379 
  1380     code_class <and_list of classes>
  1381       {(target) <and-list of class target syntax>}+
  1382         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1383 
  1384 code_instance and code_class only are effective to target Haskell.
  1385 
  1386 For example usage see src/HOL/ex/Codegenerator.thy and
  1387 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1388 generation from Isabelle/HOL theories is available via "isatool doc
  1389 codegen".
  1390 
  1391 * Code generator: consts in 'consts_code' Isar commands are now
  1392 referred to by usual term syntax (including optional type
  1393 annotations).
  1394 
  1395 * Command 'no_translations' removes translation rules from theory
  1396 syntax.
  1397 
  1398 * Overloaded definitions are now actually checked for acyclic
  1399 dependencies.  The overloading scheme is slightly more general than
  1400 that of Haskell98, although Isabelle does not demand an exact
  1401 correspondence to type class and instance declarations.
  1402 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1403 exotic versions of overloading -- at the discretion of the user!
  1404 
  1405 Polymorphic constants are represented via type arguments, i.e. the
  1406 instantiation that matches an instance against the most general
  1407 declaration given in the signature.  For example, with the declaration
  1408 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1409 as c(nat).  Overloading is essentially simultaneous structural
  1410 recursion over such type arguments.  Incomplete specification patterns
  1411 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1412 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1413 Command 'print_theory' outputs the normalized system of recursive
  1414 equations, see section "definitions".
  1415 
  1416 * Configuration options are maintained within the theory or proof
  1417 context (with name and type bool/int/string), providing a very simple
  1418 interface to a poor-man's version of general context data.  Tools may
  1419 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1420 these values using Config.get etc.  Users may change options via an
  1421 associated attribute of the same name.  This form of context
  1422 declaration works particularly well with commands 'declare' or
  1423 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1424 very easy to avoid global references, which would not observe Isar
  1425 toplevel undo/redo and fail to work with multithreading.
  1426 
  1427 Various global ML references of Pure and HOL have been turned into
  1428 configuration options:
  1429 
  1430   Unify.search_bound		unify_search_bound
  1431   Unify.trace_bound		unify_trace_bound
  1432   Unify.trace_simp		unify_trace_simp
  1433   Unify.trace_types		unify_trace_types
  1434   Simplifier.simp_depth_limit	simp_depth_limit
  1435   Blast.depth_limit		blast_depth_limit
  1436   DatatypeProp.dtK		datatype_distinctness_limit
  1437   fast_arith_neq_limit  	fast_arith_neq_limit
  1438   fast_arith_split_limit	fast_arith_split_limit
  1439 
  1440 * Named collections of theorems may be easily installed as context
  1441 data using the functor NamedThmsFun (see also
  1442 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1443 attributes; there is also a toplevel print command.  This facility is
  1444 just a common case of general context data, which is the preferred way
  1445 for anything more complex than just a list of facts in canonical
  1446 order.
  1447 
  1448 * Isar: command 'declaration' augments a local theory by generic
  1449 declaration functions written in ML.  This enables arbitrary content
  1450 being added to the context, depending on a morphism that tells the
  1451 difference of the original declaration context wrt. the application
  1452 context encountered later on.
  1453 
  1454 * Isar: proper interfaces for simplification procedures.  Command
  1455 'simproc_setup' declares named simprocs (with match patterns, and body
  1456 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1457 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1458 
  1459 * Isar: an extra pair of brackets around attribute declarations
  1460 abbreviates a theorem reference involving an internal dummy fact,
  1461 which will be ignored later --- only the effect of the attribute on
  1462 the background context will persist.  This form of in-place
  1463 declarations is particularly useful with commands like 'declare' and
  1464 'using', for example ``have A using [[simproc a]] by simp''.
  1465 
  1466 * Isar: method "assumption" (and implicit closing of subproofs) now
  1467 takes simple non-atomic goal assumptions into account: after applying
  1468 an assumption as a rule the resulting subgoals are solved by atomic
  1469 assumption steps.  This is particularly useful to finish 'obtain'
  1470 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1471 without referring to the original premise "!!x. P x ==> thesis" in the
  1472 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1473 more permissive.
  1474 
  1475 * Isar: implicit use of prems from the Isar proof context is
  1476 considered a legacy feature.  Common applications like ``have A .''
  1477 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1478 referencing facts explicitly here improves readability and
  1479 maintainability of proof texts.
  1480 
  1481 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1482 the obtained context from the course of reasoning!  For example:
  1483 
  1484   assume "EX x y. A x & B y"   -- "any previous fact"
  1485   then guess x and y by clarify
  1486 
  1487 This technique is potentially adventurous, depending on the facts and
  1488 proof tools being involved here.
  1489 
  1490 * Isar: known facts from the proof context may be specified as literal
  1491 propositions, using ASCII back-quote syntax.  This works wherever
  1492 named facts used to be allowed so far, in proof commands, proof
  1493 methods, attributes etc.  Literal facts are retrieved from the context
  1494 according to unification of type and term parameters.  For example,
  1495 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1496 theorems in the current context, then these are valid literal facts:
  1497 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1498 
  1499 There is also a proof method "fact" which does the same composition
  1500 for explicit goal states, e.g. the following proof texts coincide with
  1501 certain special cases of literal facts:
  1502 
  1503   have "A" by fact                 ==  note `A`
  1504   have "A ==> B" by fact           ==  note `A ==> B`
  1505   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1506   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1507 
  1508 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1509 outer syntax.  Thus symbolic identifiers may be used without
  1510 additional white space in declarations like this: ``assume *: A''.
  1511 
  1512 * Isar: 'print_facts' prints all local facts of the current context,
  1513 both named and unnamed ones.
  1514 
  1515 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1516 
  1517   def x == "t" and y == "u"
  1518 
  1519 * Isar: added command 'unfolding', which is structurally similar to
  1520 'using', but affects both the goal state and facts by unfolding given
  1521 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1522 'unfolded' attribute may be replaced by first-class proof text.
  1523 
  1524 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1525 and command 'unfolding' now all support object-level equalities
  1526 (potentially conditional).  The underlying notion of rewrite rule is
  1527 analogous to the 'rule_format' attribute, but *not* that of the
  1528 Simplifier (which is usually more generous).
  1529 
  1530 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1531 premises of a theorem by n. Useful in conjunction with drule.
  1532 
  1533 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1534 method expression within a sandbox consisting of the first N
  1535 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1536 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1537 simplifies all new goals that emerge from applying rule foo to the
  1538 originally first one.
  1539 
  1540 * Isar: schematic goals are no longer restricted to higher-order
  1541 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1542 expected.
  1543 
  1544 * Isar: the conclusion of a long theorem statement is now either
  1545 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1546 (essentially a disjunction of cases with local parameters and
  1547 assumptions).  The latter allows to express general elimination rules
  1548 adequately; in this notation common elimination rules look like this:
  1549 
  1550   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1551     assumes "EX x. P x"
  1552     obtains x where "P x"
  1553 
  1554   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1555     assumes "A & B"
  1556     obtains A and B
  1557 
  1558   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1559     assumes "A | B"
  1560     obtains
  1561       A
  1562     | B
  1563 
  1564 The subsequent classical rules even refer to the formal "thesis"
  1565 explicitly:
  1566 
  1567   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1568     obtains "~ thesis"
  1569 
  1570   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1571     obtains "thesis ==> something"
  1572 
  1573 The actual proof of an 'obtains' statement is analogous to that of the
  1574 Isar proof element 'obtain', only that there may be several cases.
  1575 Optional case names may be specified in parentheses; these will be
  1576 available both in the present proof and as annotations in the
  1577 resulting rule, for later use with the 'cases' method (cf. attribute
  1578 case_names).
  1579 
  1580 * Isar: the assumptions of a long theorem statement are available as
  1581 "assms" fact in the proof context.  This is more appropriate than the
  1582 (historical) "prems", which refers to all assumptions of the current
  1583 context, including those from the target locale, proof body etc.
  1584 
  1585 * Isar: 'print_statement' prints theorems from the current theory or
  1586 proof context in long statement form, according to the syntax of a
  1587 top-level lemma.
  1588 
  1589 * Isar: 'obtain' takes an optional case name for the local context
  1590 introduction rule (default "that").
  1591 
  1592 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1593 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1594 to occur.
  1595 
  1596 * Pure: syntax "CONST name" produces a fully internalized constant
  1597 according to the current context.  This is particularly useful for
  1598 syntax translations that should refer to internal constant
  1599 representations independently of name spaces.
  1600 
  1601 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1602 instead of "FOO ". This allows multiple binder declarations to coexist
  1603 in the same context.  INCOMPATIBILITY.
  1604 
  1605 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1606 primitive that also works in a locale context (both for constants and
  1607 fixed variables). Type declaration and internal syntactic representation
  1608 of given constants retrieved from the context. Likewise, the
  1609 'no_notation' command allows to remove given syntax annotations from the
  1610 current context.
  1611 
  1612 * Isar/locales: new derived specification elements 'axiomatization',
  1613 'definition', 'abbreviation', which support type-inference, admit
  1614 object-level specifications (equality, equivalence).  See also the
  1615 isar-ref manual.  Examples:
  1616 
  1617   axiomatization
  1618     eq  (infix "===" 50) where
  1619     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1620 
  1621   definition "f x y = x + y + 1"
  1622   definition g where "g x = f x x"
  1623 
  1624   abbreviation
  1625     neq  (infix "=!=" 50) where
  1626     "x =!= y == ~ (x === y)"
  1627 
  1628 These specifications may be also used in a locale context.  Then the
  1629 constants being introduced depend on certain fixed parameters, and the
  1630 constant name is qualified by the locale base name.  An internal
  1631 abbreviation takes care for convenient input and output, making the
  1632 parameters implicit and using the original short name.  See also
  1633 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1634 entities from a monomorphic theory.
  1635 
  1636 Presently, abbreviations are only available 'in' a target locale, but
  1637 not inherited by general import expressions.  Also note that
  1638 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1639 'translations' in common applications.  The "no_abbrevs" print mode
  1640 prevents folding of abbreviations in term output.
  1641 
  1642 Concrete syntax is attached to specified constants in internal form,
  1643 independently of name spaces.  The parse tree representation is
  1644 slightly different -- use 'notation' instead of raw 'syntax', and
  1645 'translations' with explicit "CONST" markup to accommodate this.
  1646 
  1647 * Pure/Isar: unified syntax for new-style specification mechanisms
  1648 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1649 full type inference and dummy patterns ("_").  For example:
  1650 
  1651   definition "K x _ = x"
  1652 
  1653   inductive conj for A B
  1654   where "A ==> B ==> conj A B"
  1655 
  1656 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1657 the current context.  Print mode "no_abbrevs" prevents inversion of
  1658 abbreviations on output.
  1659 
  1660 * Isar/locales: improved parameter handling: use of locales "var" and
  1661 "struct" no longer necessary; - parameter renamings are no longer
  1662 required to be injective.  For example, this allows to define
  1663 endomorphisms as locale endom = homom mult mult h.
  1664 
  1665 * Isar/locales: changed the way locales with predicates are defined.
  1666 Instead of accumulating the specification, the imported expression is
  1667 now an interpretation.  INCOMPATIBILITY: different normal form of
  1668 locale expressions.  In particular, in interpretations of locales with
  1669 predicates, goals repesenting already interpreted fragments are not
  1670 removed automatically.  Use methods `intro_locales' and
  1671 `unfold_locales'; see below.
  1672 
  1673 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1674 provide backward reasoning on locales predicates.  The methods are
  1675 aware of interpretations and discharge corresponding goals.
  1676 `intro_locales' is less aggressive then `unfold_locales' and does not
  1677 unfold predicates to assumptions.
  1678 
  1679 * Isar/locales: the order in which locale fragments are accumulated
  1680 has changed.  This enables to override declarations from fragments due
  1681 to interpretations -- for example, unwanted simp rules.
  1682 
  1683 * Isar/locales: interpretation in theories and proof contexts has been
  1684 extended.  One may now specify (and prove) equations, which are
  1685 unfolded in interpreted theorems.  This is useful for replacing
  1686 defined concepts (constants depending on locale parameters) by
  1687 concepts already existing in the target context.  Example:
  1688 
  1689   interpretation partial_order ["op <= :: [int, int] => bool"]
  1690     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1691 
  1692 Typically, the constant `partial_order.less' is created by a
  1693 definition specification element in the context of locale
  1694 partial_order.
  1695 
  1696 * Method "induct": improved internal context management to support
  1697 local fixes and defines on-the-fly. Thus explicit meta-level
  1698 connectives !!  and ==> are rarely required anymore in inductive goals
  1699 (using object-logic connectives for this purpose has been long
  1700 obsolete anyway). Common proof patterns are explained in
  1701 src/HOL/Induct/Common_Patterns.thy, see also
  1702 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1703 examples.
  1704 
  1705 * Method "induct": improved handling of simultaneous goals. Instead of
  1706 introducing object-level conjunction, the statement is now split into
  1707 several conclusions, while the corresponding symbolic cases are nested
  1708 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1709 see src/HOL/Induct/Common_Patterns.thy, for example.
  1710 
  1711 * Method "induct": mutual induction rules are now specified as a list
  1712 of rule sharing the same induction cases. HOL packages usually provide
  1713 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1714 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1715 mutual induction rules differently, i.e. like this:
  1716 
  1717   (induct rule: foo_bar.inducts)
  1718   (induct set: foo bar)
  1719   (induct pred: foo bar)
  1720   (induct type: foo bar)
  1721 
  1722 The ML function ProjectRule.projections turns old-style rules into the
  1723 new format.
  1724 
  1725 * Method "coinduct": dual of induction, see
  1726 src/HOL/Library/Coinductive_List.thy for various examples.
  1727 
  1728 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1729 considered a legacy feature.
  1730 
  1731 * Attribute "symmetric" produces result with standardized schematic
  1732 variables (index 0).  Potential INCOMPATIBILITY.
  1733 
  1734 * Simplifier: by default the simplifier trace only shows top level
  1735 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1736 default. Thus there is less danger of being flooded by the trace. The
  1737 trace indicates where parts have been suppressed.
  1738   
  1739 * Provers/classical: removed obsolete classical version of elim_format
  1740 attribute; classical elim/dest rules are now treated uniformly when
  1741 manipulating the claset.
  1742 
  1743 * Provers/classical: stricter checks to ensure that supplied intro,
  1744 dest and elim rules are well-formed; dest and elim rules must have at
  1745 least one premise.
  1746 
  1747 * Provers/classical: attributes dest/elim/intro take an optional
  1748 weight argument for the rule (just as the Pure versions).  Weights are
  1749 ignored by automated tools, but determine the search order of single
  1750 rule steps.
  1751 
  1752 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1753 where the body does not mention the bound variable.  Note that dummy
  1754 patterns implicitly depend on their context of bounds, which makes
  1755 "{_. _}" match any set comprehension as expected.  Potential
  1756 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1757 constant "_idtdummy" in the binding position.
  1758 
  1759 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1760 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1761 for example "A -> B" => "Pi A (%_. B)".
  1762 
  1763 * Pure: 'class_deps' command visualizes the subclass relation, using
  1764 the graph browser tool.
  1765 
  1766 * Pure: 'print_theory' now suppresses certain internal declarations by
  1767 default; use '!' option for full details.
  1768 
  1769 
  1770 *** HOL ***
  1771 
  1772 * Method "metis" proves goals by applying the Metis general-purpose
  1773 resolution prover (see also http://gilith.com/software/metis/).
  1774 Examples are in the directory MetisExamples.  WARNING: the
  1775 Isabelle/HOL-Metis integration does not yet work properly with
  1776 multi-threading.
  1777   
  1778 * Command 'sledgehammer' invokes external automatic theorem provers as
  1779 background processes.  It generates calls to the "metis" method if
  1780 successful. These can be pasted into the proof.  Users do not have to
  1781 wait for the automatic provers to return.  WARNING: does not really
  1782 work with multi-threading.
  1783 
  1784 * New "auto_quickcheck" feature tests outermost goal statements for
  1785 potential counter-examples.  Controlled by ML references
  1786 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1787 5000 milliseconds).  Fails silently if statements is outside of
  1788 executable fragment, or any other codgenerator problem occurs.
  1789 
  1790 * New constant "undefined" with axiom "undefined x = undefined".
  1791 
  1792 * Added class "HOL.eq", allowing for code generation with polymorphic
  1793 equality.
  1794 
  1795 * Some renaming of class constants due to canonical name prefixing in
  1796 the new 'class' package:
  1797 
  1798     HOL.abs ~> HOL.abs_class.abs
  1799     HOL.divide ~> HOL.divide_class.divide
  1800     0 ~> HOL.zero_class.zero
  1801     1 ~> HOL.one_class.one
  1802     op + ~> HOL.plus_class.plus
  1803     op - ~> HOL.minus_class.minus
  1804     uminus ~> HOL.minus_class.uminus
  1805     op * ~> HOL.times_class.times
  1806     op < ~> HOL.ord_class.less
  1807     op <= > HOL.ord_class.less_eq
  1808     Nat.power ~> Power.power_class.power
  1809     Nat.size ~> Nat.size_class.size
  1810     Numeral.number_of ~> Numeral.number_class.number_of
  1811     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1812     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1813     Orderings.min ~> Orderings.ord_class.min
  1814     Orderings.max ~> Orderings.ord_class.max
  1815     Divides.op div ~> Divides.div_class.div
  1816     Divides.op mod ~> Divides.div_class.mod
  1817     Divides.op dvd ~> Divides.div_class.dvd
  1818 
  1819 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1820 
  1821 a) User-defined constants using any of the names "plus", "minus",
  1822 "times", "less" or "less_eq". The standard syntax translations for
  1823 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1824 names.
  1825 
  1826 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1827 INCOMPATIBILITY: use more specific names.
  1828 
  1829 c) Permutative equations (e.g. "a + b = b + a")
  1830 Since the change of names also changes the order of terms, permutative
  1831 rewrite rules may get applied in a different order. Experience shows
  1832 that this is rarely the case (only two adaptions in the whole Isabelle
  1833 distribution).  INCOMPATIBILITY: rewrite proofs
  1834 
  1835 d) ML code directly refering to constant names
  1836 This in general only affects hand-written proof tactics, simprocs and
  1837 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1838 Consider using @{const_name} antiquotation.
  1839 
  1840 * New class "default" with associated constant "default".
  1841 
  1842 * Function "sgn" is now overloaded and available on int, real, complex
  1843 (and other numeric types), using class "sgn".  Two possible defs of
  1844 sgn are given as equational assumptions in the classes sgn_if and
  1845 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1846 INCOMPATIBILITY.
  1847 
  1848 * Locale "partial_order" now unified with class "order" (cf. theory
  1849 Orderings), added parameter "less".  INCOMPATIBILITY.
  1850 
  1851 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1852 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1853 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1854 
  1855 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1856 changed order of proof goals in instance proofs.
  1857 
  1858 * The transitivity reasoner for partial and linear orders is set up
  1859 for classes "order" and "linorder".  Instances of the reasoner are available
  1860 in all contexts importing or interpreting the corresponding locales.
  1861 Method "order" invokes the reasoner separately; the reasoner
  1862 is also integrated with the Simplifier as a solver.  Diagnostic
  1863 command 'print_orders' shows the available instances of the reasoner
  1864 in the current context.
  1865 
  1866 * Localized monotonicity predicate in theory "Orderings"; integrated
  1867 lemmas max_of_mono and min_of_mono with this predicate.
  1868 INCOMPATIBILITY.
  1869 
  1870 * Formulation of theorem "dense" changed slightly due to integration
  1871 with new class dense_linear_order.
  1872 
  1873 * Uniform lattice theory development in HOL.
  1874 
  1875     constants "meet" and "join" now named "inf" and "sup"
  1876     constant "Meet" now named "Inf"
  1877 
  1878     classes "meet_semilorder" and "join_semilorder" now named
  1879       "lower_semilattice" and "upper_semilattice"
  1880     class "lorder" now named "lattice"
  1881     class "comp_lat" now named "complete_lattice"
  1882 
  1883     Instantiation of lattice classes allows explicit definitions
  1884     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1885 
  1886   INCOMPATIBILITY.  Theorem renames:
  1887 
  1888     meet_left_le            ~> inf_le1
  1889     meet_right_le           ~> inf_le2
  1890     join_left_le            ~> sup_ge1
  1891     join_right_le           ~> sup_ge2
  1892     meet_join_le            ~> inf_sup_ord
  1893     le_meetI                ~> le_infI
  1894     join_leI                ~> le_supI
  1895     le_meet                 ~> le_inf_iff
  1896     le_join                 ~> ge_sup_conv
  1897     meet_idempotent         ~> inf_idem
  1898     join_idempotent         ~> sup_idem
  1899     meet_comm               ~> inf_commute
  1900     join_comm               ~> sup_commute
  1901     meet_leI1               ~> le_infI1
  1902     meet_leI2               ~> le_infI2
  1903     le_joinI1               ~> le_supI1
  1904     le_joinI2               ~> le_supI2
  1905     meet_assoc              ~> inf_assoc
  1906     join_assoc              ~> sup_assoc
  1907     meet_left_comm          ~> inf_left_commute
  1908     meet_left_idempotent    ~> inf_left_idem
  1909     join_left_comm          ~> sup_left_commute
  1910     join_left_idempotent    ~> sup_left_idem
  1911     meet_aci                ~> inf_aci
  1912     join_aci                ~> sup_aci
  1913     le_def_meet             ~> le_iff_inf
  1914     le_def_join             ~> le_iff_sup
  1915     join_absorp2            ~> sup_absorb2
  1916     join_absorp1            ~> sup_absorb1
  1917     meet_absorp1            ~> inf_absorb1
  1918     meet_absorp2            ~> inf_absorb2
  1919     meet_join_absorp        ~> inf_sup_absorb
  1920     join_meet_absorp        ~> sup_inf_absorb
  1921     distrib_join_le         ~> distrib_sup_le
  1922     distrib_meet_le         ~> distrib_inf_le
  1923 
  1924     add_meet_distrib_left   ~> add_inf_distrib_left
  1925     add_join_distrib_left   ~> add_sup_distrib_left
  1926     is_join_neg_meet        ~> is_join_neg_inf
  1927     is_meet_neg_join        ~> is_meet_neg_sup
  1928     add_meet_distrib_right  ~> add_inf_distrib_right
  1929     add_join_distrib_right  ~> add_sup_distrib_right
  1930     add_meet_join_distribs  ~> add_sup_inf_distribs
  1931     join_eq_neg_meet        ~> sup_eq_neg_inf
  1932     meet_eq_neg_join        ~> inf_eq_neg_sup
  1933     add_eq_meet_join        ~> add_eq_inf_sup
  1934     meet_0_imp_0            ~> inf_0_imp_0
  1935     join_0_imp_0            ~> sup_0_imp_0
  1936     meet_0_eq_0             ~> inf_0_eq_0
  1937     join_0_eq_0             ~> sup_0_eq_0
  1938     neg_meet_eq_join        ~> neg_inf_eq_sup
  1939     neg_join_eq_meet        ~> neg_sup_eq_inf
  1940     join_eq_if              ~> sup_eq_if
  1941 
  1942     mono_meet               ~> mono_inf
  1943     mono_join               ~> mono_sup
  1944     meet_bool_eq            ~> inf_bool_eq
  1945     join_bool_eq            ~> sup_bool_eq
  1946     meet_fun_eq             ~> inf_fun_eq
  1947     join_fun_eq             ~> sup_fun_eq
  1948     meet_set_eq             ~> inf_set_eq
  1949     join_set_eq             ~> sup_set_eq
  1950     meet1_iff               ~> inf1_iff
  1951     meet2_iff               ~> inf2_iff
  1952     meet1I                  ~> inf1I
  1953     meet2I                  ~> inf2I
  1954     meet1D1                 ~> inf1D1
  1955     meet2D1                 ~> inf2D1
  1956     meet1D2                 ~> inf1D2
  1957     meet2D2                 ~> inf2D2
  1958     meet1E                  ~> inf1E
  1959     meet2E                  ~> inf2E
  1960     join1_iff               ~> sup1_iff
  1961     join2_iff               ~> sup2_iff
  1962     join1I1                 ~> sup1I1
  1963     join2I1                 ~> sup2I1
  1964     join1I1                 ~> sup1I1
  1965     join2I2                 ~> sup1I2
  1966     join1CI                 ~> sup1CI
  1967     join2CI                 ~> sup2CI
  1968     join1E                  ~> sup1E
  1969     join2E                  ~> sup2E
  1970 
  1971     is_meet_Meet            ~> is_meet_Inf
  1972     Meet_bool_def           ~> Inf_bool_def
  1973     Meet_fun_def            ~> Inf_fun_def
  1974     Meet_greatest           ~> Inf_greatest
  1975     Meet_lower              ~> Inf_lower
  1976     Meet_set_def            ~> Inf_set_def
  1977 
  1978     Sup_def                 ~> Sup_Inf
  1979     Sup_bool_eq             ~> Sup_bool_def
  1980     Sup_fun_eq              ~> Sup_fun_def
  1981     Sup_set_eq              ~> Sup_set_def
  1982 
  1983     listsp_meetI            ~> listsp_infI
  1984     listsp_meet_eq          ~> listsp_inf_eq
  1985 
  1986     meet_min                ~> inf_min
  1987     join_max                ~> sup_max
  1988 
  1989 * Added syntactic class "size"; overloaded constant "size" now has
  1990 type "'a::size ==> bool"
  1991 
  1992 * Internal reorganisation of `size' of datatypes: size theorems
  1993 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1994 simplification rules by default!); theorems "prod.size" now named
  1995 "*.size".
  1996 
  1997 * Class "div" now inherits from class "times" rather than "type".
  1998 INCOMPATIBILITY.
  1999 
  2000 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2001 Linorder etc.  have disappeared; operations defined in terms of
  2002 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2003 
  2004 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2005 
  2006 * HOL-Word: New extensive library and type for generic, fixed size
  2007 machine words, with arithemtic, bit-wise, shifting and rotating
  2008 operations, reflection into int, nat, and bool lists, automation for
  2009 linear arithmetic (by automatic reflection into nat or int), including
  2010 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2011 arithmetic type classes, supporting automatic simplification of
  2012 numerals on all operations.
  2013 
  2014 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2015 
  2016 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2017 
  2018 * Code generator library theories:
  2019   - Code_Integer represents HOL integers by big integer literals in target
  2020     languages.
  2021   - Code_Char represents HOL characters by character literals in target
  2022     languages.
  2023   - Code_Char_chr like Code_Char, but also offers treatment of character
  2024     codes; includes Code_Integer.
  2025   - Executable_Set allows to generate code for finite sets using lists.
  2026   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2027     denominator).
  2028   - Executable_Real implements a subset of real numbers, namly those
  2029     representable by rational numbers.
  2030   - Efficient_Nat implements natural numbers by integers, which in general will
  2031     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2032     includes Code_Integer.
  2033   - Code_Index provides an additional datatype index which is mapped to
  2034     target-language built-in integers.
  2035   - Code_Message provides an additional datatype message_string which is isomorphic to
  2036     strings; messages are mapped to target-language strings.
  2037 
  2038 * New package for inductive predicates
  2039 
  2040   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2041 
  2042     inductive
  2043       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2044       for z_1 :: U_1 and ... and z_n :: U_m
  2045     where
  2046       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2047     | ...
  2048 
  2049   with full support for type-inference, rather than
  2050 
  2051     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2052 
  2053     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2054     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2055 
  2056     inductive "s z_1 ... z_m"
  2057     intros
  2058       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2059       ...
  2060 
  2061   For backward compatibility, there is a wrapper allowing inductive
  2062   sets to be defined with the new package via
  2063 
  2064     inductive_set
  2065       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2066       for z_1 :: U_1 and ... and z_n :: U_m
  2067     where
  2068       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2069     | ...
  2070 
  2071   or
  2072 
  2073     inductive_set
  2074       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2075       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2076       for z_1 :: U_1 and ... and z_n :: U_m
  2077     where
  2078       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2079     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2080     | ...
  2081 
  2082   if the additional syntax "p ..." is required.
  2083 
  2084   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2085   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2086 
  2087   INCOMPATIBILITIES:
  2088 
  2089   - Since declaration and definition of inductive sets or predicates
  2090     is no longer separated, abbreviations involving the newly
  2091     introduced sets or predicates must be specified together with the
  2092     introduction rules after the 'where' keyword (see above), rather
  2093     than before the actual inductive definition.
  2094 
  2095   - The variables in induction and elimination rules are now
  2096     quantified in the order of their occurrence in the introduction
  2097     rules, rather than in alphabetical order. Since this may break
  2098     some proofs, these proofs either have to be repaired, e.g. by
  2099     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2100     statements of the form
  2101 
  2102       case (rule_i a_i_1 ... a_i_{k_i})
  2103 
  2104     or the old order of quantification has to be restored by explicitly adding
  2105     meta-level quantifiers in the introduction rules, i.e.
  2106 
  2107       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2108 
  2109   - The format of the elimination rules is now
  2110 
  2111       p z_1 ... z_m x_1 ... x_n ==>
  2112         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2113         ==> ... ==> P
  2114 
  2115     for predicates and
  2116 
  2117       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2118         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2119         ==> ... ==> P
  2120 
  2121     for sets rather than
  2122 
  2123       x : s z_1 ... z_m ==>
  2124         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2125         ==> ... ==> P
  2126 
  2127     This may require terms in goals to be expanded to n-tuples
  2128     (e.g. using case_tac or simplification with the split_paired_all
  2129     rule) before the above elimination rule is applicable.
  2130 
  2131   - The elimination or case analysis rules for (mutually) inductive
  2132     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2133     list of rules "p_1_..._p_k.elims" is no longer available.
  2134 
  2135 * New package "function"/"fun" for general recursive functions,
  2136 supporting mutual and nested recursion, definitions in local contexts,
  2137 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2138 for small examples, and the separate tutorial on the function
  2139 package. The old recdef "package" is still available as before, but
  2140 users are encouraged to use the new package.
  2141 
  2142 * Method "lexicographic_order" automatically synthesizes termination
  2143 relations as lexicographic combinations of size measures. 
  2144 
  2145 * Case-expressions allow arbitrary constructor-patterns (including
  2146 "_") and take their order into account, like in functional
  2147 programming.  Internally, this is translated into nested
  2148 case-expressions; missing cases are added and mapped to the predefined
  2149 constant "undefined". In complicated cases printing may no longer show
  2150 the original input but the internal form. Lambda-abstractions allow
  2151 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2152 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2153 variable.
  2154 
  2155 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2156 is an abbreviation for "of_nat :: nat => int". The simplification
  2157 rules for "of_nat" have been changed to work like "int" did
  2158 previously.  Potential INCOMPATIBILITY:
  2159   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2160   - of_nat_diff and of_nat_mult are no longer default simp rules
  2161 
  2162 * Method "algebra" solves polynomial equations over (semi)rings using
  2163 Groebner bases. The (semi)ring structure is defined by locales and the
  2164 tool setup depends on that generic context. Installing the method for
  2165 a specific type involves instantiating the locale and possibly adding
  2166 declarations for computation on the coefficients.  The method is
  2167 already instantiated for natural numbers and for the axiomatic class
  2168 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2169 CALCULEMUS 2007 for the general principles underlying this
  2170 architecture of context-aware proof-tools.
  2171 
  2172 * Method "ferrack" implements quantifier elimination over
  2173 special-purpose dense linear orders using locales (analogous to
  2174 "algebra"). The method is already installed for class
  2175 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2176 rat, etc.
  2177 
  2178 * Former constant "List.op @" now named "List.append".  Use ML
  2179 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2180 circumvent possible incompatibilities when working on ML level.
  2181 
  2182 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2183 
  2184 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2185 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2186 
  2187 * New syntax for Haskell-like list comprehension (input only), eg.
  2188 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2189 
  2190 * The special syntax for function "filter" has changed from [x :
  2191 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2192 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2193 
  2194 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2195 defined on nat only, as an abbreviation for [a..<Suc b]
  2196 INCOMPATIBILITY.
  2197 
  2198 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2199 
  2200 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2201 
  2202 * New lemma collection field_simps (an extension of ring_simps) for
  2203 manipulating (in)equations involving division. Multiplies with all
  2204 denominators that can be proved to be non-zero (in equations) or
  2205 positive/negative (in inequations).
  2206 
  2207 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2208 have been improved and renamed to ring_simps, group_simps and
  2209 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2210 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2211 
  2212 * Theory Library/Commutative_Ring: switched from recdef to function
  2213 package; constants add, mul, pow now curried.  Infix syntax for
  2214 algebraic operations.
  2215 
  2216 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2217 INCOMPATIBILITY.
  2218 
  2219 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2220 INCOMPATIBILITY.
  2221 
  2222 * HOL/records: generalised field-update to take a function on the
  2223 field rather than the new value: r(|A := x|) is translated to A_update
  2224 (K x) r The K-combinator that is internally used is called K_record.
  2225 INCOMPATIBILITY: Usage of the plain update functions has to be
  2226 adapted.
  2227  
  2228 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2229 * x = 0, which are required for a semiring.  Richer structures do not
  2230 inherit from semiring_0 anymore, because this property is a theorem
  2231 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2232 there is more to prove, but this is mostly trivial.
  2233 
  2234 * Class "recpower" is generalized to arbitrary monoids, not just
  2235 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2236 commutativity or semiring properties additionally.
  2237 
  2238 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2239 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2240 better use 'abbreviation'.
  2241 
  2242 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2243 
  2244 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2245 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2246 significant changes for setting up numeral syntax for types:
  2247   - New constants Numeral.pred and Numeral.succ instead
  2248       of former Numeral.bin_pred and Numeral.bin_succ.
  2249   - Use integer operations instead of bin_add, bin_mult and so on.
  2250   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2251   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2252 
  2253 See src/HOL/Integ/IntArith.thy for an example setup.
  2254 
  2255 * Command 'normal_form' computes the normal form of a term that may
  2256 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2257 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2258 heavy-duty computations because the functions are compiled to ML
  2259 first.  Correspondingly, a method "normalization" is provided.  See
  2260 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2261 
  2262 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2263 25 like -->); output depends on the "iff" print_mode, the default is
  2264 "A = B" (with priority 50).
  2265 
  2266 * Relations less (<) and less_eq (<=) are also available on type bool.
  2267 Modified syntax to disallow nesting without explicit parentheses,
  2268 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2269 INCOMPATIBILITY.
  2270 
  2271 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2272 
  2273 * Relation composition operator "op O" now has precedence 75 and binds
  2274 stronger than union and intersection. INCOMPATIBILITY.
  2275 
  2276 * The old set interval syntax "{m..n(}" (and relatives) has been
  2277 removed.  Use "{m..<n}" (and relatives) instead.
  2278 
  2279 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2280 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2281 ``declare [[simproc del: neq]]''.
  2282 
  2283 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2284 True/False.
  2285 
  2286 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2287 
  2288 * Theorem setsum_mult renamed to setsum_right_distrib.
  2289 
  2290 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2291 ``rule'' method.
  2292 
  2293 * Reimplemented methods "sat" and "satx", with several improvements:
  2294 goals no longer need to be stated as "<prems> ==> False", equivalences
  2295 (i.e. "=" on type bool) are handled, variable names of the form
  2296 "lit_<n>" are no longer reserved, significant speedup.
  2297 
  2298 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2299 zChaff is still supported as well.
  2300 
  2301 * 'inductive' and 'datatype': provide projections of mutual rules,
  2302 bundled as foo_bar.inducts;
  2303 
  2304 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2305 Library.
  2306 
  2307 * Library: moved theory Accessible_Part to main HOL.
  2308 
  2309 * Library: added theory Coinductive_List of potentially infinite lists
  2310 as greatest fixed-point.
  2311 
  2312 * Library: added theory AssocList which implements (finite) maps as
  2313 association lists.
  2314 
  2315 * Method "evaluation" solves goals (i.e. a boolean expression)
  2316 efficiently by compiling it to ML.  The goal is "proved" (via an
  2317 oracle) if it evaluates to True.
  2318 
  2319 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2320 also when invoked by the simplifier.  This results in the Simplifier
  2321 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2322 Configuration option fast_arith_split_limit=0 recovers the old
  2323 behavior.
  2324 
  2325 * Support for hex (0x20) and binary (0b1001) numerals.
  2326 
  2327 * New method: reify eqs (t), where eqs are equations for an
  2328 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2329 parameter, computes a term s::'b and a list xs::'a list and proves the
  2330 theorem I xs s = t. This is also known as reification or quoting. The
  2331 resulting theorem is applied to the subgoal to substitute t with I xs
  2332 s.  If t is omitted, the subgoal itself is reified.
  2333 
  2334 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2335 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2336 where f is supposed to be a computable function (in the sense of code
  2337 generattion). The method uses reify to compute s and xs as above then
  2338 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2339 r and finally gets the theorem t = r, which is again applied to the
  2340 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2341 
  2342 * Reflection: Automatic reification now handels binding, an example is
  2343 available in src/HOL/ex/ReflectionEx.thy
  2344 
  2345 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2346 command 'statespace' that is similar to 'record', but introduces an
  2347 abstract specification based on the locale infrastructure instead of
  2348 HOL types.  This leads to extra flexibility in composing state spaces,
  2349 in particular multiple inheritance and renaming of components.
  2350 
  2351 
  2352 *** HOL-Complex ***
  2353 
  2354 * Hyperreal: Functions root and sqrt are now defined on negative real
  2355 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2356 Nonnegativity side conditions have been removed from many lemmas, so
  2357 that more subgoals may now be solved by simplification; potential
  2358 INCOMPATIBILITY.
  2359 
  2360 * Real: new type classes formalize real normed vector spaces and
  2361 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2362 and norm :: 'a => real.
  2363 
  2364 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2365 reals into other types. The overloaded constant Reals :: 'a set is now
  2366 defined as range of_real; potential INCOMPATIBILITY.
  2367 
  2368 * Real: proper support for ML code generation, including 'quickcheck'.
  2369 Reals are implemented as arbitrary precision rationals.
  2370 
  2371 * Hyperreal: Several constants that previously worked only for the
  2372 reals have been generalized, so they now work over arbitrary vector
  2373 spaces. Type annotations may need to be added in some cases; potential
  2374 INCOMPATIBILITY.
  2375 
  2376   Infinitesimal  :: ('a::real_normed_vector) star set
  2377   HFinite        :: ('a::real_normed_vector) star set
  2378   HInfinite      :: ('a::real_normed_vector) star set
  2379   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2380   monad          :: ('a::real_normed_vector) star => 'a star set
  2381   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2382   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2383   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2384   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2385   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2386   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2387   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2388   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2389   sgn            :: 'a::real_normed_vector => 'a
  2390   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2391 
  2392 * Complex: Some complex-specific constants are now abbreviations for
  2393 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2394 hnorm.  Other constants have been entirely removed in favor of the
  2395 polymorphic versions (INCOMPATIBILITY):
  2396 
  2397   approx        <-- capprox
  2398   HFinite       <-- CFinite
  2399   HInfinite     <-- CInfinite
  2400   Infinitesimal <-- CInfinitesimal
  2401   monad         <-- cmonad
  2402   galaxy        <-- cgalaxy
  2403   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2404   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2405   (ns)deriv     <-- (ns)cderiv
  2406 
  2407 
  2408 *** HOL-Algebra ***
  2409 
  2410 * Formalisation of ideals and the quotient construction over rings.
  2411 
  2412 * Order and lattice theory no longer based on records.
  2413 INCOMPATIBILITY.
  2414 
  2415 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2416 greatest_closed.  INCOMPATIBILITY.
  2417 
  2418 * Method algebra is now set up via an attribute.  For examples see
  2419 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2420 of algebraic structures.
  2421 
  2422 * Renamed theory CRing to Ring.
  2423 
  2424 
  2425 *** HOL-Nominal ***
  2426 
  2427 * Substantial, yet incomplete support for nominal datatypes (binding
  2428 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2429 src/HOL/Nominal/Examples.  Prospective users should consult
  2430 http://isabelle.in.tum.de/nominal/
  2431 
  2432 
  2433 *** ML ***
  2434 
  2435 * ML basics: just one true type int, which coincides with IntInf.int
  2436 (even on SML/NJ).
  2437 
  2438 * ML within Isar: antiquotations allow to embed statically-checked
  2439 formal entities in the source, referring to the context available at
  2440 compile-time.  For example:
  2441 
  2442 ML {* @{sort "{zero,one}"} *}
  2443 ML {* @{typ "'a => 'b"} *}
  2444 ML {* @{term "%x. x"} *}
  2445 ML {* @{prop "x == y"} *}
  2446 ML {* @{ctyp "'a => 'b"} *}
  2447 ML {* @{cterm "%x. x"} *}
  2448 ML {* @{cprop "x == y"} *}
  2449 ML {* @{thm asm_rl} *}
  2450 ML {* @{thms asm_rl} *}
  2451 ML {* @{type_name c} *}
  2452 ML {* @{type_syntax c} *}
  2453 ML {* @{const_name c} *}
  2454 ML {* @{const_syntax c} *}
  2455 ML {* @{context} *}
  2456 ML {* @{theory} *}
  2457 ML {* @{theory Pure} *}
  2458 ML {* @{theory_ref} *}
  2459 ML {* @{theory_ref Pure} *}
  2460 ML {* @{simpset} *}
  2461 ML {* @{claset} *}
  2462 ML {* @{clasimpset} *}
  2463 
  2464 The same works for sources being ``used'' within an Isar context.
  2465 
  2466 * ML in Isar: improved error reporting; extra verbosity with
  2467 ML_Context.trace enabled.
  2468 
  2469 * Pure/General/table.ML: the join operations now works via exceptions
  2470 DUP/SAME instead of type option. This is simpler in simple cases, and
  2471 admits slightly more efficient complex applications.
  2472 
  2473 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2474 use Context.generic instead of just theory.
  2475 
  2476 * Pure: datatype Context.generic joins theory/Proof.context and
  2477 provides some facilities for code that works in either kind of
  2478 context, notably GenericDataFun for uniform theory and proof data.
  2479 
  2480 * Pure: simplified internal attribute type, which is now always
  2481 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2482 local (Proof.context) attributes have been discontinued, while
  2483 minimizing code duplication. Thm.rule_attribute and
  2484 Thm.declaration_attribute build canonical attributes; see also structure
  2485 Context for further operations on Context.generic, notably
  2486 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2487 declarations and definitions.
  2488 
  2489 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2490 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2491 init only required for impure data. INCOMPATIBILITY: empty really need
  2492 to be empty (no dependencies on theory content!)
  2493 
  2494 * Pure/kernel: consts certification ignores sort constraints given in
  2495 signature declarations. (This information is not relevant to the
  2496 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2497 potential INCOMPATIBILITY.
  2498 
  2499 * Pure: axiomatic type classes are now purely definitional, with
  2500 explicit proofs of class axioms and super class relations performed
  2501 internally. See Pure/axclass.ML for the main internal interfaces --
  2502 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2503 AxClass.axiomatize_class/classrel/arity supersede
  2504 Sign.add_classes/classrel/arities.
  2505 
  2506 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2507 global/local versions on theory vs. Proof.context have been
  2508 discontinued; Attrib.syntax and Method.syntax have been adapted
  2509 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2510 attributes, methods, etc.
  2511 
  2512 * Pure: several functions of signature "... -> theory -> theory * ..."
  2513 have been reoriented to "... -> theory -> ... * theory" in order to
  2514 allow natural usage in combination with the ||>, ||>>, |-> and
  2515 fold_map combinators.
  2516 
  2517 * Pure: official theorem names (closed derivations) and additional
  2518 comments (tags) are now strictly separate.  Name hints -- which are
  2519 maintained as tags -- may be attached any time without affecting the
  2520 derivation.
  2521 
  2522 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2523 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2524 achieve the old behaviour.
  2525 
  2526 * Pure: the "Goal" constant is now called "prop", supporting a
  2527 slightly more general idea of ``protecting'' meta-level rule
  2528 statements.
  2529 
  2530 * Pure: Logic.(un)varify only works in a global context, which is now
  2531 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2532 Logic.legacy_(un)varify as temporary workaround.
  2533 
  2534 * Pure: structure Name provides scalable operations for generating
  2535 internal variable names, notably Name.variants etc.  This replaces
  2536 some popular functions from term.ML:
  2537 
  2538   Term.variant		->  Name.variant
  2539   Term.variantlist	->  Name.variant_list
  2540   Term.invent_names	->  Name.invent_list
  2541 
  2542 Note that low-level renaming rarely occurs in new code -- operations
  2543 from structure Variable are used instead (see below).
  2544 
  2545 * Pure: structure Variable provides fundamental operations for proper
  2546 treatment of fixed/schematic variables in a context.  For example,
  2547 Variable.import introduces fixes for schematics of given facts and
  2548 Variable.export reverses the effect (up to renaming) -- this replaces
  2549 various freeze_thaw operations.
  2550 
  2551 * Pure: structure Goal provides simple interfaces for
  2552 init/conclude/finish and tactical prove operations (replacing former
  2553 Tactic.prove).  Goal.prove is the canonical way to prove results
  2554 within a given context; Goal.prove_global is a degraded version for
  2555 theory level goals, including a global Drule.standard.  Note that
  2556 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2557 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2558 in a locale context).
  2559 
  2560 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2561 and type checking (Syntax.check_term etc.), with common combinations
  2562 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2563 which are considered legacy and await removal.
  2564 
  2565 * Pure/Syntax: generic interfaces for type unchecking
  2566 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2567 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2568 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2569 available for convenience, but refer to the very same operations using
  2570 a mere theory instead of a full context.
  2571 
  2572 * Isar: simplified treatment of user-level errors, using exception
  2573 ERROR of string uniformly.  Function error now merely raises ERROR,
  2574 without any side effect on output channels.  The Isar toplevel takes
  2575 care of proper display of ERROR exceptions.  ML code may use plain
  2576 handle/can/try; cat_error may be used to concatenate errors like this:
  2577 
  2578   ... handle ERROR msg => cat_error msg "..."
  2579 
  2580 Toplevel ML code (run directly or through the Isar toplevel) may be
  2581 embedded into the Isar toplevel with exception display/debug like
  2582 this:
  2583 
  2584   Isar.toplevel (fn () => ...)
  2585 
  2586 INCOMPATIBILITY, removed special transform_error facilities, removed
  2587 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2588 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2589 -- use plain ERROR instead.
  2590 
  2591 * Isar: theory setup now has type (theory -> theory), instead of a
  2592 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2593 
  2594 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2595 ProofContext.debug/verbose flags.
  2596 
  2597 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2598 theory before entering a proof state.  Transactions now always see a
  2599 quasi-functional intermediate checkpoint, both in interactive and
  2600 batch mode.
  2601 
  2602 * Isar: simplified interfaces for outer syntax.  Renamed
  2603 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2604 OuterSyntax.add_parsers -- this functionality is now included in
  2605 OuterSyntax.command etc.  INCOMPATIBILITY.
  2606 
  2607 * Simplifier: the simpset of a running simplification process now
  2608 contains a proof context (cf. Simplifier.the_context), which is the
  2609 very context that the initial simpset has been retrieved from (by
  2610 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2611 (solver, looper etc.) may depend on arbitrary proof data.
  2612 
  2613 * Simplifier.inherit_context inherits the proof context (plus the
  2614 local bounds) of the current simplification process; any simproc
  2615 etc. that calls the Simplifier recursively should do this!  Removed
  2616 former Simplifier.inherit_bounds, which is already included here --
  2617 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2618 specify an explicit context using Simplifier.context/theory_context.
  2619 
  2620 * Simplifier/Classical Reasoner: more abstract interfaces
  2621 change_simpset/claset for modifying the simpset/claset reference of a
  2622 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2623 INCOMPATIBILITY.
  2624 
  2625 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2626 "Trueprop" etc.
  2627 
  2628 
  2629 *** System ***
  2630 
  2631 * settings: the default heap location within ISABELLE_HOME_USER now
  2632 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2633 Isabelle installations.
  2634 
  2635 * isabelle-process: option -S (secure mode) disables some critical
  2636 operations, notably runtime compilation and evaluation of ML source
  2637 code.
  2638 
  2639 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2640 
  2641 * Support for parallel execution, using native multicore support of
  2642 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2643 independent theories, according to the given theory header
  2644 specifications. The maximum number of worker threads is specified via
  2645 usedir option -M or the "max-threads" setting in Proof General. A
  2646 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2647 to 6 on a 8-core machine.  User-code needs to observe certain
  2648 guidelines for thread-safe programming, see appendix A in the Isar
  2649 Implementation manual.
  2650 
  2651 
  2652 
  2653 New in Isabelle2005 (October 2005)
  2654 ----------------------------------
  2655 
  2656 *** General ***
  2657 
  2658 * Theory headers: the new header syntax for Isar theories is
  2659 
  2660   theory <name>
  2661   imports <theory1> ... <theoryN>
  2662   uses <file1> ... <fileM>
  2663   begin
  2664 
  2665 where the 'uses' part is optional.  The previous syntax
  2666 
  2667   theory <name> = <theory1> + ... + <theoryN>:
  2668 
  2669 will disappear in the next release.  Use isatool fixheaders to convert
  2670 existing theory files.  Note that there is no change in ancient
  2671 non-Isar theories now, but these will disappear soon.
  2672 
  2673 * Theory loader: parent theories can now also be referred to via
  2674 relative and absolute paths.
  2675 
  2676 * Command 'find_theorems' searches for a list of criteria instead of a
  2677 list of constants. Known criteria are: intro, elim, dest, name:string,
  2678 simp:term, and any term. Criteria can be preceded by '-' to select
  2679 theorems that do not match. Intro, elim, dest select theorems that
  2680 match the current goal, name:s selects theorems whose fully qualified
  2681 name contain s, and simp:term selects all simplification rules whose
  2682 lhs match term.  Any other term is interpreted as pattern and selects
  2683 all theorems matching the pattern. Available in ProofGeneral under
  2684 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2685 
  2686   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2687 
  2688 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2689 matching the current goal as introduction rule and not having "HOL."
  2690 in their name (i.e. not being defined in theory HOL).
  2691 
  2692 * Command 'thms_containing' has been discontinued in favour of
  2693 'find_theorems'; INCOMPATIBILITY.
  2694 
  2695 * Communication with Proof General is now 8bit clean, which means that
  2696 Unicode text in UTF-8 encoding may be used within theory texts (both
  2697 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2698 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2699 
  2700   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2701   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2702 
  2703 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2704 Classical Reasoner.  Typical big applications run around 2 times
  2705 faster.
  2706 
  2707 
  2708 *** Document preparation ***
  2709 
  2710 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2711 of raw sources.  Only those symbols that do not require additional
  2712 LaTeX packages (depending on comments in isabellesym.sty) are
  2713 displayed properly, everything else is left verbatim.  isatool display
  2714 and isatool print are used as front ends (these are subject to the
  2715 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2716 
  2717 * Command tags control specific markup of certain regions of text,
  2718 notably folding and hiding.  Predefined tags include "theory" (for
  2719 theory begin and end), "proof" for proof commands, and "ML" for
  2720 commands involving ML code; the additional tags "visible" and
  2721 "invisible" are unused by default.  Users may give explicit tag
  2722 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2723 interpretation of tags is determined by the LaTeX job during document
  2724 preparation: see option -V of isatool usedir, or options -n and -t of
  2725 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2726 \isadroptag.
  2727 
  2728 Several document versions may be produced at the same time via isatool
  2729 usedir (the generated index.html will link all of them).  Typical
  2730 specifications include ''-V document=theory,proof,ML'' to present
  2731 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2732 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2733 these parts without any formal replacement text.  The Isabelle site
  2734 default settings produce ''document'' and ''outline'' versions as
  2735 specified above.
  2736 
  2737 * Several new antiquotations:
  2738 
  2739   @{term_type term} prints a term with its type annotated;
  2740 
  2741   @{typeof term} prints the type of a term;
  2742 
  2743   @{const const} is the same as @{term const}, but checks that the
  2744   argument is a known logical constant;
  2745 
  2746   @{term_style style term} and @{thm_style style thm} print a term or
  2747   theorem applying a "style" to it
  2748 
  2749   @{ML text}
  2750 
  2751 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2752 definitions, equations, inequations etc., 'concl' printing only the
  2753 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2754 to print the specified premise.  TermStyle.add_style provides an ML
  2755 interface for introducing further styles.  See also the "LaTeX Sugar"
  2756 document practical applications.  The ML antiquotation prints
  2757 type-checked ML expressions verbatim.
  2758 
  2759 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2760 and 'text' support optional locale specification '(in loc)', which
  2761 specifies the default context for interpreting antiquotations.  For
  2762 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2763 
  2764 * Option 'locale=NAME' of antiquotations specifies an alternative
  2765 context interpreting the subsequent argument.  For example: @{thm
  2766 [locale=lattice] inf_assoc}.
  2767 
  2768 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2769 a proof context.
  2770 
  2771 * Proper output of antiquotations for theory commands involving a
  2772 proof context (such as 'locale' or 'theorem (in loc) ...').
  2773 
  2774 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2775 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2776 
  2777 * isatool usedir: new option -C (default true) controls whether option
  2778 -D should include a copy of the original document directory; -C false
  2779 prevents unwanted effects such as copying of administrative CVS data.
  2780 
  2781 
  2782 *** Pure ***
  2783 
  2784 * Considerably improved version of 'constdefs' command.  Now performs
  2785 automatic type-inference of declared constants; additional support for
  2786 local structure declarations (cf. locales and HOL records), see also
  2787 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2788 sequential dependencies of definitions within a single 'constdefs'
  2789 section; moreover, the declared name needs to be an identifier.  If
  2790 all fails, consider to fall back on 'consts' and 'defs' separately.
  2791 
  2792 * Improved indexed syntax and implicit structures.  First of all,
  2793 indexed syntax provides a notational device for subscripted
  2794 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2795 expressions.  Secondly, in a local context with structure
  2796 declarations, number indexes \<^sub>n or the empty index (default
  2797 number 1) refer to a certain fixed variable implicitly; option
  2798 show_structs controls printing of implicit structures.  Typical
  2799 applications of these concepts involve record types and locales.
  2800 
  2801 * New command 'no_syntax' removes grammar declarations (and
  2802 translations) resulting from the given syntax specification, which is
  2803 interpreted in the same manner as for the 'syntax' command.
  2804 
  2805 * 'Advanced' translation functions (parse_translation etc.) may depend
  2806 on the signature of the theory context being presently used for
  2807 parsing/printing, see also isar-ref manual.
  2808 
  2809 * Improved 'oracle' command provides a type-safe interface to turn an
  2810 ML expression of type theory -> T -> term into a primitive rule of
  2811 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2812 is already included here); see also FOL/ex/IffExample.thy;
  2813 INCOMPATIBILITY.
  2814 
  2815 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2816 before); "cI" is no longer bound, use "c.intro" instead.
  2817 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2818 axclasses vs. locales.
  2819 
  2820 * Improved internal renaming of symbolic identifiers -- attach primes
  2821 instead of base 26 numbers.
  2822 
  2823 * New flag show_question_marks controls printing of leading question
  2824 marks in schematic variable names.
  2825 
  2826 * In schematic variable names, *any* symbol following \<^isub> or
  2827 \<^isup> is now treated as part of the base name.  For example, the
  2828 following works without printing of awkward ".0" indexes:
  2829 
  2830   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2831     by simp
  2832 
  2833 * Inner syntax includes (*(*nested*) comments*).
  2834 
  2835 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2836 annotations as "(00...)".
  2837 
  2838 * Clear separation of logical types and nonterminals, where the latter
  2839 may only occur in 'syntax' specifications or type abbreviations.
  2840 Before that distinction was only partially implemented via type class
  2841 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2842 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2843 exotic syntax specifications may require further adaption
  2844 (e.g. Cube/Cube.thy).
  2845 
  2846 * Removed obsolete type class "logic", use the top sort {} instead.
  2847 Note that non-logical types should be declared as 'nonterminals'
  2848 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2849 specifications.
  2850 
  2851 * Attributes 'induct' and 'cases': type or set names may now be
  2852 locally fixed variables as well.
  2853 
  2854 * Simplifier: can now control the depth to which conditional rewriting
  2855 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2856 Limit.
  2857 
  2858 * Simplifier: simplification procedures may now take the current
  2859 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2860 interface), which is very useful for calling the Simplifier
  2861 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2862 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2863 low-level mk_simproc no longer applies Logic.varify internally, to
  2864 allow for use in a context of fixed variables.
  2865 
  2866 * thin_tac now works even if the assumption being deleted contains !!
  2867 or ==>.  More generally, erule now works even if the major premise of
  2868 the elimination rule contains !! or ==>.
  2869 
  2870 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2871 
  2872 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2873 from Pure, which contains all common declarations already.  Both
  2874 theories are defined via plain Isabelle/Isar .thy files.
  2875 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2876 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2877 use isatool fixcpure to adapt your theory and ML sources.
  2878 
  2879 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2880 selections of theorems in named facts via index ranges.
  2881 
  2882 * 'print_theorems': in theory mode, really print the difference
  2883 wrt. the last state (works for interactive theory development only),
  2884 in proof mode print all local facts (cf. 'print_facts');
  2885 
  2886 * 'hide': option '(open)' hides only base names.
  2887 
  2888 * More efficient treatment of intermediate checkpoints in interactive
  2889 theory development.
  2890 
  2891 * Code generator is now invoked via code_module (incremental code
  2892 generation) and code_library (modular code generation, ML structures
  2893 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2894 must be quoted when used as identifiers.
  2895 
  2896 * New 'value' command for reading, evaluating and printing terms using
  2897 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2898 quoted when used as identifier.
  2899 
  2900 
  2901 *** Locales ***
  2902 
  2903 * New commands for the interpretation of locale expressions in
  2904 theories (1), locales (2) and proof contexts (3).  These generate
  2905 proof obligations from the expression specification.  After the
  2906 obligations have been discharged, theorems of the expression are added
  2907 to the theory, target locale or proof context.  The synopsis of the
  2908 commands is a follows:
  2909 
  2910   (1) interpretation expr inst
  2911   (2) interpretation target < expr
  2912   (3) interpret expr inst
  2913 
  2914 Interpretation in theories and proof contexts require a parameter
  2915 instantiation of terms from the current context.  This is applied to
  2916 specifications and theorems of the interpreted expression.
  2917 Interpretation in locales only permits parameter renaming through the
  2918 locale expression.  Interpretation is smart in that interpretations
  2919 that are active already do not occur in proof obligations, neither are
  2920 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2921 inspect active interpretations of a particular locale.  For details,
  2922 see the Isar Reference manual.  Examples can be found in
  2923 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2924 
  2925 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2926 'interpret' instead.
  2927 
  2928 * New context element 'constrains' for adding type constraints to
  2929 parameters.
  2930 
  2931 * Context expressions: renaming of parameters with syntax
  2932 redeclaration.
  2933 
  2934 * Locale declaration: 'includes' disallowed.
  2935 
  2936 * Proper static binding of attribute syntax -- i.e. types / terms /
  2937 facts mentioned as arguments are always those of the locale definition
  2938 context, independently of the context of later invocations.  Moreover,
  2939 locale operations (renaming and type / term instantiation) are applied
  2940 to attribute arguments as expected.
  2941 
  2942 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2943 actual attributes; rare situations may require Attrib.attribute to
  2944 embed those attributes into Attrib.src that lack concrete syntax.
  2945 Attribute implementations need to cooperate properly with the static
  2946 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2947 Attrib.XXX_thm etc. already do the right thing without further
  2948 intervention.  Only unusual applications -- such as "where" or "of"
  2949 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2950 on the context and the facts involved -- may have to assign parsed
  2951 values to argument tokens explicitly.
  2952 
  2953 * Changed parameter management in theorem generation for long goal
  2954 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2955 theorem statement in rare situations.
  2956 
  2957 * Locale inspection command 'print_locale' omits notes elements.  Use
  2958 'print_locale!' to have them included in the output.
  2959 
  2960 
  2961 *** Provers ***
  2962 
  2963 * Provers/hypsubst.ML: improved version of the subst method, for
  2964 single-step rewriting: it now works in bound variable contexts. New is
  2965 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2966 rewrite a different subterm than the original subst method, which is
  2967 still available as 'simplesubst'.
  2968 
  2969 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2970 and quasi orders.
  2971 
  2972 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2973 reflexive-transitive closure of relations.
  2974 
  2975 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2976 limit (previously hard-coded with a value of 20) user-definable.
  2977 
  2978 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2979 is peformed already.  Object-logics merely need to finish their
  2980 initial simpset configuration as before.  INCOMPATIBILITY.
  2981 
  2982 
  2983 *** HOL ***
  2984 
  2985 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2986 
  2987   syntax (epsilon)
  2988     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2989 
  2990 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2991 and x-symbol; use option '-m epsilon' to get it actually printed.
  2992 Moreover, the mathematically important symbolic identifier \<epsilon>
  2993 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2994 
  2995 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2996 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2997 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2998 support corresponding Isar calculations.
  2999 
  3000 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3001 instead of ":".
  3002 
  3003 * theory SetInterval: changed the syntax for open intervals:
  3004 
  3005   Old       New
  3006   {..n(}    {..<n}
  3007   {)n..}    {n<..}
  3008   {m..n(}   {m..<n}
  3009   {)m..n}   {m<..n}
  3010   {)m..n(}  {m<..<n}
  3011 
  3012 The old syntax is still supported but will disappear in the next
  3013 release.  For conversion use the following Emacs search and replace
  3014 patterns (these are not perfect but work quite well):
  3015 
  3016   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3017   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3018 
  3019 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3020 equalities in commutative rings; method 'algebra' provides a generic
  3021 interface.
  3022 
  3023 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3024 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3025 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3026 be a tuple pattern.
  3027 
  3028 Some new syntax forms are available:
  3029 
  3030   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3031   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3032   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3033   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3034 
  3035 The latter form "\<Sum>x < k. e" used to be based on a separate
  3036 function "Summation", which has been discontinued.
  3037 
  3038 * theory Finite_Set: in structured induction proofs, the insert case
  3039 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3040 (insert F x)'.
  3041 
  3042 * The 'refute' command has been extended to support a much larger
  3043 fragment of HOL, including axiomatic type classes, constdefs and
  3044 typedefs, inductive datatypes and recursion.
  3045 
  3046 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3047 Requires zChaff with proof generation to be installed.  See
  3048 HOL/ex/SAT_Examples.thy for examples.
  3049 
  3050 * Datatype induction via method 'induct' now preserves the name of the
  3051 induction variable. For example, when proving P(xs::'a list) by
  3052 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3053 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3054 in unstructured proof scripts.
  3055 
  3056 * Reworked implementation of records.  Improved scalability for
  3057 records with many fields, avoiding performance problems for type
  3058 inference. Records are no longer composed of nested field types, but
  3059 of nested extension types. Therefore the record type only grows linear
  3060 in the number of extensions and not in the number of fields.  The
  3061 top-level (users) view on records is preserved.  Potential
  3062 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3063 old record representation. The type generated for a record is called
  3064 <record_name>_ext_type.
  3065 
  3066 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3067 proofs triggered by a record definition or a simproc (if
  3068 quick_and_dirty is enabled).  Definitions of large records can take
  3069 quite long.
  3070 
  3071 New simproc record_upd_simproc for simplification of multiple record
  3072 updates enabled by default.  Moreover, trivial updates are also
  3073 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3074 occasionally, since simplification is more powerful by default.
  3075 
  3076 * typedef: proper support for polymorphic sets, which contain extra
  3077 type-variables in the term.
  3078 
  3079 * Simplifier: automatically reasons about transitivity chains
  3080 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3081 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3082 old proofs break occasionally as simplification may now solve more
  3083 goals than previously.
  3084 
  3085 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3086 present.  Works for all partial orders (class "order"), in particular
  3087 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3088 just like y <= x.
  3089 
  3090 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3091 bound variable or a constant then the let is unfolded.  Otherwise
  3092 first a is simplified to b, and then f b is simplified to g. If
  3093 possible we abstract b from g arriving at "let x = b in h x",
  3094 otherwise we unfold the let and arrive at g.  The simproc can be
  3095 enabled/disabled by the reference use_let_simproc.  Potential
  3096 INCOMPATIBILITY since simplification is more powerful by default.
  3097 
  3098 * Classical reasoning: the meson method now accepts theorems as arguments.
  3099 
  3100 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3101 jobs to provide advice on the provability of subgoals.
  3102 
  3103 * Theory OrderedGroup and Ring_and_Field: various additions and
  3104 improvements to faciliate calculations involving equalities and
  3105 inequalities.
  3106 
  3107 The following theorems have been eliminated or modified
  3108 (INCOMPATIBILITY):
  3109 
  3110   abs_eq             now named abs_of_nonneg
  3111   abs_of_ge_0        now named abs_of_nonneg
  3112   abs_minus_eq       now named abs_of_nonpos
  3113   imp_abs_id         now named abs_of_nonneg
  3114   imp_abs_neg_id     now named abs_of_nonpos
  3115   mult_pos           now named mult_pos_pos
  3116   mult_pos_le        now named mult_nonneg_nonneg
  3117   mult_pos_neg_le    now named mult_nonneg_nonpos
  3118   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3119   mult_neg           now named mult_neg_neg
  3120   mult_neg_le        now named mult_nonpos_nonpos
  3121 
  3122 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3123      
  3124      zero_le_square
  3125      not_square_less_zero 
  3126 
  3127   The following lemmas have been deleted from Real/RealPow:
  3128   
  3129      realpow_zero_zero
  3130      realpow_two
  3131      realpow_less
  3132      zero_le_power
  3133      realpow_two_le
  3134      abs_realpow_two
  3135      realpow_two_abs     
  3136 
  3137 * Theory Parity: added rules for simplifying exponents.
  3138 
  3139 * Theory List:
  3140 
  3141 The following theorems have been eliminated or modified
  3142 (INCOMPATIBILITY):
  3143 
  3144   list_all_Nil       now named list_all.simps(1)
  3145   list_all_Cons      now named list_all.simps(2)
  3146   list_all_conv      now named list_all_iff
  3147   set_mem_eq         now named mem_iff
  3148 
  3149 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3150 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3151 
  3152 
  3153 *** HOL-Complex ***
  3154 
  3155 * Theory RealDef: better support for embedding natural numbers and
  3156 integers in the reals.
  3157 
  3158 The following theorems have been eliminated or modified
  3159 (INCOMPATIBILITY):
  3160 
  3161   exp_ge_add_one_self  now requires no hypotheses
  3162   real_of_int_add      reversed direction of equality (use [symmetric])
  3163   real_of_int_minus    reversed direction of equality (use [symmetric])
  3164   real_of_int_diff     reversed direction of equality (use [symmetric])
  3165   real_of_int_mult     reversed direction of equality (use [symmetric])
  3166 
  3167 * Theory RComplete: expanded support for floor and ceiling functions.
  3168 
  3169 * Theory Ln is new, with properties of the natural logarithm
  3170 
  3171 * Hyperreal: There is a new type constructor "star" for making
  3172 nonstandard types.  The old type names are now type synonyms:
  3173 
  3174   hypreal = real star
  3175   hypnat = nat star
  3176   hcomplex = complex star
  3177 
  3178 * Hyperreal: Many groups of similarly-defined constants have been
  3179 replaced by polymorphic versions (INCOMPATIBILITY):
  3180 
  3181   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3182 
  3183   starset      <-- starsetNat, starsetC
  3184   *s*          <-- *sNat*, *sc*
  3185   starset_n    <-- starsetNat_n, starsetC_n
  3186   *sn*         <-- *sNatn*, *scn*
  3187   InternalSets <-- InternalNatSets, InternalCSets
  3188 
  3189   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3190   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3191   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3192   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3193   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3194 
  3195 * Hyperreal: Many type-specific theorems have been removed in favor of
  3196 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3197 
  3198   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3199   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3200   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3201   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3202   right_minus <-- hypreal_add_minus
  3203   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3204   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3205   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3206   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3207   mult_1_right <-- hcomplex_mult_one_right
  3208   mult_zero_left <-- hcomplex_mult_zero_left
  3209   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3210   right_distrib <-- hypnat_add_mult_distrib2
  3211   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3212   right_inverse <-- hypreal_mult_inverse
  3213   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3214   order_refl <-- {hypreal,hypnat}_le_refl
  3215   order_trans <-- {hypreal,hypnat}_le_trans
  3216   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3217   order_less_le <-- {hypreal,hypnat}_less_le
  3218   linorder_linear <-- {hypreal,hypnat}_le_linear
  3219   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3220   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3221   add_nonneg_nonneg <-- hypreal_le_add_order
  3222 
  3223 * Hyperreal: Separate theorems having to do with type-specific
  3224 versions of constants have been merged into theorems that apply to the
  3225 new polymorphic constants (INCOMPATIBILITY):
  3226 
  3227   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3228   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3229   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3230   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3231   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3232   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3233   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3234   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3235   STAR_diff <-- {STAR,STARC}_diff
  3236   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3237     STARC_hcomplex_of_complex}_image_subset
  3238   starset_n_Un <-- starset{Nat,C}_n_Un
  3239   starset_n_Int <-- starset{Nat,C}_n_Int
  3240   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3241   starset_n_diff <-- starset{Nat,C}_n_diff
  3242   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3243   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3244   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3245   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3246   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3247   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3248   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3249   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3250   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3251   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3252   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3253   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3254   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3255   starfun_diff <-- starfun{C,RC,CR}_diff
  3256   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3257   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3258   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3259   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3260   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3261   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3262   starfun_Id <-- starfunC_Id
  3263   starfun_approx <-- starfun{Nat,CR}_approx
  3264   starfun_capprox <-- starfun{C,RC}_capprox
  3265   starfun_abs <-- starfunNat_rabs
  3266   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3267   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3268   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3269   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3270   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3271   starfun_add_approx <-- starfunCR_add_approx
  3272   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3273   starfun_divide <-- starfun{C,CR,RC}_divide
  3274   starfun_n <-- starfun{Nat,C}_n
  3275   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3276   starfun_n_add <-- starfun{Nat,C}_n_add
  3277   starfun_n_add_minus <-- starfunNat_n_add_minus
  3278   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3279   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3280   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3281 
  3282   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3283   star_n_minus <-- {hypreal,hcomplex}_minus
  3284   star_n_diff <-- {hypreal,hcomplex}_diff
  3285   star_n_mult <-- {hypreal,hcomplex}_mult
  3286   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3287   star_n_le <-- {hypreal,hypnat}_le
  3288   star_n_less <-- {hypreal,hypnat}_less
  3289   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3290   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3291   star_n_abs <-- hypreal_hrabs
  3292   star_n_divide <-- hcomplex_divide
  3293 
  3294   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3295   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3296   star_of_diff <-- hypreal_of_real_diff
  3297   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3298   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3299   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3300   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3301   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3302   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3303   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3304   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3305   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3306   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3307   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3308   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3309   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3310   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3311   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3312   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3313   star_of_power <-- hypreal_of_real_power
  3314   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3315 
  3316 * Hyperreal: new method "transfer" that implements the transfer
  3317 principle of nonstandard analysis. With a subgoal that mentions
  3318 nonstandard types like "'a star", the command "apply transfer"
  3319 replaces it with an equivalent one that mentions only standard types.
  3320 To be successful, all free variables must have standard types; non-
  3321 standard variables must have explicit universal quantifiers.
  3322 
  3323 * Hyperreal: A theory of Taylor series.
  3324 
  3325 
  3326 *** HOLCF ***
  3327 
  3328 * Discontinued special version of 'constdefs' (which used to support
  3329 continuous functions) in favor of the general Pure one with full
  3330 type-inference.
  3331 
  3332 * New simplification procedure for solving continuity conditions; it
  3333 is much faster on terms with many nested lambda abstractions (cubic
  3334 instead of exponential time).
  3335 
  3336 * New syntax for domain package: selector names are now optional.
  3337 Parentheses should be omitted unless argument is lazy, for example:
  3338 
  3339   domain 'a stream = cons "'a" (lazy "'a stream")
  3340 
  3341 * New command 'fixrec' for defining recursive functions with pattern
  3342 matching; defining multiple functions with mutual recursion is also
  3343 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3344 sinr, or any data constructor defined by the domain package. The given
  3345 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3346 syntax and examples.
  3347 
  3348 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3349 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3350 but the proof obligation additionally includes an admissibility
  3351 requirement. The packages generate instances of class cpo or pcpo,
  3352 with continuity and strictness theorems for Rep and Abs.
  3353 
  3354 * HOLCF: Many theorems have been renamed according to a more standard naming
  3355 scheme (INCOMPATIBILITY):
  3356 
  3357   foo_inject:  "foo$x = foo$y ==> x = y"
  3358   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3359   foo_less:    "(foo$x << foo$y) = (x << y)"
  3360   foo_strict:  "foo$UU = UU"
  3361   foo_defined: "... ==> foo$x ~= UU"
  3362   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3363 
  3364 
  3365 *** ZF ***
  3366 
  3367 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3368 including the First Isomorphism Theorem (on quotienting by the kernel
  3369 of a homomorphism).
  3370 
  3371 * ZF/Simplifier: install second copy of type solver that actually
  3372 makes use of TC rules declared to Isar proof contexts (or locales);
  3373 the old version is still required for ML proof scripts.
  3374 
  3375 
  3376 *** Cube ***
  3377 
  3378 * Converted to Isar theory format; use locales instead of axiomatic
  3379 theories.
  3380 
  3381 
  3382 *** ML ***
  3383 
  3384 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3385 for ||>, ||>>, |>>,
  3386 
  3387 * Pure/library.ML no longer defines its own option datatype, but uses
  3388 that of the SML basis, which has constructors NONE and SOME instead of
  3389 None and Some, as well as exception Option.Option instead of OPTION.
  3390 The functions the, if_none, is_some, is_none have been adapted
  3391 accordingly, while Option.map replaces apsome.
  3392 
  3393 * Pure/library.ML: the exception LIST has been given up in favour of
  3394 the standard exceptions Empty and Subscript, as well as
  3395 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3396 superceded by the standard hd and tl functions etc.
  3397 
  3398 A number of basic list functions are no longer exported to the ML
  3399 toplevel, as they are variants of predefined functions.  The following
  3400 suggests how one can translate existing code:
  3401 
  3402     rev_append xs ys = List.revAppend (xs, ys)
  3403     nth_elem (i, xs) = List.nth (xs, i)
  3404     last_elem xs = List.last xs
  3405     flat xss = List.concat xss
  3406     seq fs = List.app fs
  3407     partition P xs = List.partition P xs
  3408     mapfilter f xs = List.mapPartial f xs
  3409 
  3410 * Pure/library.ML: several combinators for linear functional
  3411 transformations, notably reverse application and composition:
  3412 
  3413   x |> f                f #> g
  3414   (x, y) |-> f          f #-> g
  3415 
  3416 * Pure/library.ML: introduced/changed precedence of infix operators:
  3417 
  3418   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3419   infix 2 ?;
  3420   infix 3 o oo ooo oooo;
  3421   infix 4 ~~ upto downto;
  3422 
  3423 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3424 infix operators.
  3425 
  3426 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3427 fold_map support linear functional transformations and nesting.  For
  3428 example:
  3429 
  3430   fold f [x1, ..., xN] y =
  3431     y |> f x1 |> ... |> f xN
  3432 
  3433   (fold o fold) f [xs1, ..., xsN] y =
  3434     y |> fold f xs1 |> ... |> fold f xsN
  3435 
  3436   fold f [x1, ..., xN] =
  3437     f x1 #> ... #> f xN
  3438 
  3439   (fold o fold) f [xs1, ..., xsN] =
  3440     fold f xs1 #> ... #> fold f xsN
  3441 
  3442 * Pure/library.ML: the following selectors on type 'a option are
  3443 available:
  3444 
  3445   the:               'a option -> 'a  (*partial*)
  3446   these:             'a option -> 'a  where 'a = 'b list
  3447   the_default: 'a -> 'a option -> 'a
  3448   the_list:          'a option -> 'a list
  3449 
  3450 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3451 basic operations for association lists, following natural argument
  3452 order; moreover the explicit equality predicate passed here avoids
  3453 potentially expensive polymorphic runtime equality checks.
  3454 The old functions may be expressed as follows:
  3455 
  3456   assoc = uncurry (AList.lookup (op =))
  3457   assocs = these oo AList.lookup (op =)
  3458   overwrite = uncurry (AList.update (op =)) o swap
  3459 
  3460 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3461 
  3462   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3463   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3464 
  3465 replacing make_keylist and keyfilter (occassionally used)
  3466 Naive rewrites:
  3467 
  3468   make_keylist = AList.make
  3469   keyfilter = AList.find (op =)
  3470 
  3471 * eq_fst and eq_snd now take explicit equality parameter, thus
  3472   avoiding eqtypes. Naive rewrites:
  3473 
  3474     eq_fst = eq_fst (op =)
  3475     eq_snd = eq_snd (op =)
  3476 
  3477 * Removed deprecated apl and apr (rarely used).
  3478   Naive rewrites:
  3479 
  3480     apl (n, op) =>>= curry op n
  3481     apr (op, m) =>>= fn n => op (n, m)
  3482 
  3483 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3484 provides a reasonably efficient light-weight implementation of sets as
  3485 lists.
  3486 
  3487 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3488 few new operations; existing lookup and update are now curried to
  3489 follow natural argument order (for use with fold etc.);
  3490 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3491 
  3492 * Pure/General: output via the Isabelle channels of
  3493 writeln/warning/error etc. is now passed through Output.output, with a
  3494 hook for arbitrary transformations depending on the print_mode
  3495 (cf. Output.add_mode -- the first active mode that provides a output
  3496 function wins).  Already formatted output may be embedded into further
  3497 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3498 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3499 accommodate easy composition of diagnostic messages etc.  Programmers
  3500 rarely need to care about Output.output or Output.raw at all, with
  3501 some notable exceptions: Output.output is required when bypassing the
  3502 standard channels (writeln etc.), or in token translations to produce
  3503 properly formatted results; Output.raw is required when capturing
  3504 already output material that will eventually be presented to the user
  3505 a second time.  For the default print mode, both Output.output and
  3506 Output.raw have no effect.
  3507 
  3508 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3509 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3510 cumulative results are displayed at the end of a batch session.
  3511 
  3512 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3513 replaced by File.platform_path and File.shell_path (with appropriate
  3514 hooks).  This provides a clean interface for unusual systems where the
  3515 internal and external process view of file names are different.
  3516 
  3517 * Pure: more efficient orders for basic syntactic entities: added
  3518 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3519 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3520 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3521 orders now -- potential INCOMPATIBILITY for code that depends on a
  3522 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3523 Library.sort_strings on result).
  3524 
  3525 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3526 fold_types traverse types/terms from left to right, observing natural
  3527 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3528 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3529 
  3530 * Pure: name spaces have been refined, with significant changes of the
  3531 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3532 to extern(_table).  The plain name entry path is superceded by a
  3533 general 'naming' context, which also includes the 'policy' to produce
  3534 a fully qualified name and external accesses of a fully qualified
  3535 name; NameSpace.extend is superceded by context dependent
  3536 Sign.declare_name.  Several theory and proof context operations modify
  3537 the naming context.  Especially note Theory.restore_naming and
  3538 ProofContext.restore_naming to get back to a sane state; note that
  3539 Theory.add_path is no longer sufficient to recover from
  3540 Theory.absolute_path in particular.
  3541 
  3542 * Pure: new flags short_names (default false) and unique_names
  3543 (default true) for controlling output of qualified names.  If
  3544 short_names is set, names are printed unqualified.  If unique_names is
  3545 reset, the name prefix is reduced to the minimum required to achieve
  3546 the original result when interning again, even if there is an overlap
  3547 with earlier declarations.
  3548 
  3549 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3550 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3551 (useful for printing error messages).  INCOMPATIBILITY.
  3552 
  3553 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3554 Theory.theory are now identified, referring to the universal
  3555 Context.theory (see Pure/context.ML).  Actual signature and theory
  3556 content is managed as theory data.  The old code and interfaces were
  3557 spread over many files and structures; the new arrangement introduces
  3558 considerable INCOMPATIBILITY to gain more clarity:
  3559 
  3560   Context -- theory management operations (name, identity, inclusion,
  3561     parents, ancestors, merge, etc.), plus generic theory data;
  3562 
  3563   Sign -- logical signature and syntax operations (declaring consts,
  3564     types, etc.), plus certify/read for common entities;
  3565 
  3566   Theory -- logical theory operations (stating axioms, definitions,
  3567     oracles), plus a copy of logical signature operations (consts,
  3568     types, etc.); also a few basic management operations (Theory.copy,
  3569     Theory.merge, etc.)
  3570 
  3571 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3572 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3573 for convenience -- they merely return the theory.
  3574 
  3575 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3576 
  3577 * Pure: the Isar proof context type is already defined early in Pure
  3578 as Context.proof (note that ProofContext.context and Proof.context are
  3579 aliases, where the latter is the preferred name).  This enables other
  3580 Isabelle components to refer to that type even before Isar is present.
  3581 
  3582 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3583 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3584 any of these kinds.  For example, Sign.intern typeK is now
  3585 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3586 Theory.hide_types.  Also note that former
  3587 Theory.hide_classes/types/consts are now
  3588 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3589 internalize their arguments!  INCOMPATIBILITY.
  3590 
  3591 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3592 datatype thmref (with constructors Name and NameSelection) instead of
  3593 plain string -- INCOMPATIBILITY;
  3594 
  3595 * Pure: cases produced by proof methods specify options, where NONE
  3596 means to remove case bindings -- INCOMPATIBILITY in
  3597 (RAW_)METHOD_CASES.
  3598 
  3599 * Pure: the following operations retrieve axioms or theorems from a
  3600 theory node or theory hierarchy, respectively:
  3601 
  3602   Theory.axioms_of: theory -> (string * term) list
  3603   Theory.all_axioms_of: theory -> (string * term) list
  3604   PureThy.thms_of: theory -> (string * thm) list
  3605   PureThy.all_thms_of: theory -> (string * thm) list
  3606 
  3607 * Pure: print_tac now outputs the goal through the trace channel.
  3608 
  3609 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3610 Reference Toplevel.debug (default false) controls detailed printing
  3611 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3612 controls execution profiling -- set to 1 for time and 2 for space
  3613 (both increase the runtime).
  3614 
  3615 * Isar session: The initial use of ROOT.ML is now always timed,
  3616 i.e. the log will show the actual process times, in contrast to the
  3617 elapsed wall-clock time that the outer shell wrapper produces.
  3618 
  3619 * Simplifier: improved handling of bound variables (nameless
  3620 representation, avoid allocating new strings).  Simprocs that invoke
  3621 the Simplifier recursively should use Simplifier.inherit_bounds to
  3622 avoid local name clashes.  Failure to do so produces warnings
  3623 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3624 for further details.
  3625 
  3626 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3627 bindings for all theorems stored within a given theory; this may help
  3628 in porting non-Isar theories to Isar ones, while keeping ML proof
  3629 scripts for the time being.
  3630 
  3631 * ML operator HTML.with_charset specifies the charset begin used for
  3632 generated HTML files.  For example:
  3633 
  3634   HTML.with_charset "utf-8" use_thy "Hebrew";
  3635   HTML.with_charset "utf-8" use_thy "Chinese";
  3636 
  3637 
  3638 *** System ***
  3639 
  3640 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3641 isabelle, isatool etc.).
  3642 
  3643 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3644 isatool doc, isatool mkdir, display_drafts etc.).
  3645 
  3646 * isatool usedir: option -f allows specification of the ML file to be
  3647 used by Isabelle; default is ROOT.ML.
  3648 
  3649 * New isatool version outputs the version identifier of the Isabelle
  3650 distribution being used.
  3651 
  3652 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3653 (containing Boolean satisfiability problems) into Isabelle/HOL
  3654 theories.
  3655 
  3656 
  3657 
  3658 New in Isabelle2004 (April 2004)
  3659 --------------------------------
  3660 
  3661 *** General ***
  3662 
  3663 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3664   Replaces linorder.ML.
  3665 
  3666 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3667   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3668   (\<a>...\<z>), are now considered normal letters, and can therefore
  3669   be used anywhere where an ASCII letter (a...zA...Z) has until
  3670   now. COMPATIBILITY: This obviously changes the parsing of some
  3671   terms, especially where a symbol has been used as a binder, say
  3672   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3673   as an identifier.  Fix it by inserting a space around former
  3674   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3675   existing theory and ML files.
  3676 
  3677 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3678 
  3679 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3680   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3681   a normal (but invisible) letter. For multiple letter subscripts repeat
  3682   \<^isub> like this: x\<^isub>1\<^isub>2.
  3683 
  3684 * Pure: There are now sub-/superscripts that can span more than one
  3685   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3686   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3687   superscript. The new control characters are not identifier parts.
  3688 
  3689 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3690   content of "..." to the latex file instead of \isacntrl... . The "..."
  3691   may consist of any printable characters excluding the end bracket >.
  3692 
  3693 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3694   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3695   declare constants "final", which prevents their being given a definition
  3696   later.  It is useful for constants whose behaviour is fixed axiomatically
  3697   rather than definitionally, such as the meta-logic connectives.
  3698 
  3699 * Pure: 'instance' now handles general arities with general sorts
  3700   (i.e. intersections of classes),
  3701 
  3702 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3703   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3704   It can be changed to alter the colors/layout of generated pages.
  3705 
  3706 
  3707 *** Isar ***
  3708 
  3709 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3710   cut_tac, subgoal_tac and thin_tac:
  3711   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3712     locales are no longer forced to write Isar proof scripts.
  3713     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3714     emulations.
  3715   - INCOMPATIBILITY: names of variables to be instantiated may no
  3716     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3717     This is consistent with the instantiation attribute "where".
  3718 
  3719 * Attributes "where" and "of":
  3720   - Now take type variables of instantiated theorem into account when reading
  3721     the instantiation string.  This fixes a bug that caused instantiated
  3722     theorems to have too special types in some circumstances.
  3723   - "where" permits explicit instantiations of type variables.
  3724 
  3725 * Calculation commands "moreover" and "also" no longer interfere with
  3726   current facts ("this"), admitting arbitrary combinations with "then"
  3727   and derived forms.
  3728 
  3729 * Locales:
  3730   - Goal statements involving the context element "includes" no longer
  3731     generate theorems with internal delta predicates (those ending on
  3732     "_axioms") in the premise.
  3733     Resolve particular premise with <locale>.intro to obtain old form.
  3734   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3735     specification and "includes" elements in goal statement.
  3736   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3737     [intro?] and [elim?] (respectively) by default.
  3738   - Experimental command for instantiation of locales in proof contexts:
  3739         instantiate <label>[<attrs>]: <loc>
  3740     Instantiates locale <loc> and adds all its theorems to the current context
  3741     taking into account their attributes.  Label and attrs are optional
  3742     modifiers, like in theorem declarations.  If present, names of
  3743     instantiated theorems are qualified with <label>, and the attributes
  3744     <attrs> are applied after any attributes these theorems might have already.
  3745       If the locale has assumptions, a chained fact of the form
  3746     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3747     are derived.  The command does not support old-style locales declared
  3748     with "locale (open)".
  3749       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3750 
  3751 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3752   (Isar) contexts.
  3753 
  3754 
  3755 *** HOL ***
  3756 
  3757 * Proof import: new image HOL4 contains the imported library from
  3758   the HOL4 system with about 2500 theorems. It is imported by
  3759   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3760   can be used like any other Isabelle image.  See
  3761   HOL/Import/HOL/README for more information.
  3762 
  3763 * Simplifier:
  3764   - Much improved handling of linear and partial orders.
  3765     Reasoners for linear and partial orders are set up for type classes
  3766     "linorder" and "order" respectively, and are added to the default simpset
  3767     as solvers.  This means that the simplifier can build transitivity chains
  3768     to solve goals from the assumptions.
  3769   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3770     of blast or auto after simplification become unnecessary because the goal
  3771     is solved by simplification already.
  3772 
  3773 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3774     all proved in axiomatic type classes for semirings, rings and fields.
  3775 
  3776 * Numerics:
  3777   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3778     now formalized using the Ring_and_Field theory mentioned above.
  3779   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3780     than before, because now they are set up once in a generic manner.
  3781   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3782     Look for the general versions in Ring_and_Field (and Power if they concern
  3783     exponentiation).
  3784 
  3785 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3786 
  3787 * Records:
  3788   - Record types are now by default printed with their type abbreviation
  3789     instead of the list of all field types. This can be configured via
  3790     the reference "print_record_type_abbr".
  3791   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3792     (not enabled by default).
  3793   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3794     EX x. x = sel r to True (not enabled by default).
  3795   - Tactic "record_split_simp_tac" to split and simplify records added.
  3796 
  3797 * 'specification' command added, allowing for definition by
  3798   specification.  There is also an 'ax_specification' command that
  3799   introduces the new constants axiomatically.
  3800 
  3801 * arith(_tac) is now able to generate counterexamples for reals as well.
  3802 
  3803 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3804 
  3805 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3806   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3807 
  3808 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3809   matrix theory to linear programming.
  3810 
  3811 * Unions and Intersections:
  3812   The latex output syntax of UN and INT has been changed
  3813   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3814   i.e. the index formulae has become a subscript.
  3815   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3816 
  3817 * Unions and Intersections over Intervals:
  3818   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3819   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3820   like in normal math, and corresponding versions for < and for intersection.
  3821 
  3822 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3823   lexicographic dictonary ordering has been added as "lexord".
  3824 
  3825 * ML: the legacy theory structures Int and List have been removed. They had
  3826   conflicted with ML Basis Library structures having the same names.
  3827 
  3828 * 'refute' command added to search for (finite) countermodels.  Only works
  3829   for a fragment of HOL.  The installation of an external SAT solver is
  3830   highly recommended.  See "HOL/Refute.thy" for details.
  3831 
  3832 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3833   formulae under an assignment of free variables to random values.
  3834   In contrast to 'refute', it can deal with inductive datatypes,
  3835   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3836   for examples.
  3837 
  3838 
  3839 *** HOLCF ***
  3840 
  3841 * Streams now come with concatenation and are part of the HOLCF image
  3842 
  3843 
  3844 
  3845 New in Isabelle2003 (May 2003)
  3846 ------------------------------
  3847 
  3848 *** General ***
  3849 
  3850 * Provers/simplifier:
  3851 
  3852   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3853     Assumptions are now subject to complete mutual simplification,
  3854     not just from left to right. The simplifier now preserves
  3855     the order of assumptions.
  3856 
  3857     Potential INCOMPATIBILITY:
  3858 
  3859     -- simp sometimes diverges where the old version did
  3860        not, e.g. invoking simp on the goal
  3861 
  3862         [| P (f x); y = x; f x = f y |] ==> Q
  3863 
  3864        now gives rise to the infinite reduction sequence
  3865 
  3866         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3867 
  3868        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3869        kind of problem.
  3870 
  3871     -- Tactics combining classical reasoner and simplification (such as auto)
  3872        are also affected by this change, because many of them rely on
  3873        simp. They may sometimes diverge as well or yield a different numbers
  3874        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3875        in case of problems. Sometimes subsequent calls to the classical
  3876        reasoner will fail because a preceeding call to the simplifier too
  3877        eagerly simplified the goal, e.g. deleted redundant premises.
  3878 
  3879   - The simplifier trace now shows the names of the applied rewrite rules
  3880 
  3881   - You can limit the number of recursive invocations of the simplifier
  3882     during conditional rewriting (where the simplifie tries to solve the
  3883     conditions before applying the rewrite rule):
  3884     ML "simp_depth_limit := n"
  3885     where n is an integer. Thus you can force termination where previously
  3886     the simplifier would diverge.
  3887 
  3888   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3889 
  3890   - No longer aborts on failed congruence proof.  Instead, the
  3891     congruence is ignored.
  3892 
  3893 * Pure: New generic framework for extracting programs from constructive
  3894   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3895   as HOL/Extraction for some case studies.
  3896 
  3897 * Pure: The main goal of the proof state is no longer shown by default, only
  3898 the subgoals. This behaviour is controlled by a new flag.
  3899    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3900 (ML: Proof.show_main_goal).
  3901 
  3902 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3903 rules whose conclusion matches subgoal 1:
  3904       PG menu: Isabelle/Isar -> Show me -> matching rules
  3905 The rules are ordered by how closely they match the subgoal.
  3906 In particular, rules that solve a subgoal outright are displayed first
  3907 (or rather last, the way they are printed).
  3908 (ML: ProofGeneral.print_intros())
  3909 
  3910 * Pure: New flag trace_unify_fail causes unification to print
  3911 diagnostic information (PG: in trace buffer) when it fails. This is
  3912 useful for figuring out why single step proofs like rule, erule or
  3913 assumption failed.
  3914 
  3915 * Pure: Locale specifications now produce predicate definitions
  3916 according to the body of text (covering assumptions modulo local
  3917 definitions); predicate "loc_axioms" covers newly introduced text,
  3918 while "loc" is cumulative wrt. all included locale expressions; the
  3919 latter view is presented only on export into the global theory
  3920 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3921 on the old view without predicates;
  3922 
  3923 * Pure: predefined locales "var" and "struct" are useful for sharing
  3924 parameters (as in CASL, for example); just specify something like
  3925 ``var x + var y + struct M'' as import;
  3926 
  3927 * Pure: improved thms_containing: proper indexing of facts instead of
  3928 raw theorems; check validity of results wrt. current name space;
  3929 include local facts of proof configuration (also covers active
  3930 locales), cover fixed variables in index; may use "_" in term
  3931 specification; an optional limit for the number of printed facts may
  3932 be given (the default is 40);
  3933 
  3934 * Pure: disallow duplicate fact bindings within new-style theory files
  3935 (batch-mode only);
  3936 
  3937 * Provers: improved induct method: assumptions introduced by case
  3938 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3939 the goal statement); "foo" still refers to all facts collectively;
  3940 
  3941 * Provers: the function blast.overloaded has been removed: all constants
  3942 are regarded as potentially overloaded, which improves robustness in exchange
  3943 for slight decrease in efficiency;
  3944 
  3945 * Provers/linorder: New generic prover for transitivity reasoning over
  3946 linear orders.  Note: this prover is not efficient!
  3947 
  3948 * Isar: preview of problems to finish 'show' now produce an error
  3949 rather than just a warning (in interactive mode);
  3950 
  3951 
  3952 *** HOL ***
  3953 
  3954 * arith(_tac)
  3955 
  3956  - Produces a counter example if it cannot prove a goal.
  3957    Note that the counter example may be spurious if the goal is not a formula
  3958    of quantifier-free linear arithmetic.
  3959    In ProofGeneral the counter example appears in the trace buffer.
  3960 
  3961  - Knows about div k and mod k where k is a numeral of type nat or int.
  3962 
  3963  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3964    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3965    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3966 
  3967 * simp's arithmetic capabilities have been enhanced a bit: it now
  3968 takes ~= in premises into account (by performing a case split);
  3969 
  3970 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3971 are distributed over a sum of terms;
  3972 
  3973 * New tactic "trans_tac" and method "trans" instantiate
  3974 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3975 "<=", "<" and "=").
  3976 
  3977 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3978 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3979 
  3980 * 'typedef' command has new option "open" to suppress the set
  3981 definition;
  3982 
  3983 * functions Min and Max on finite sets have been introduced (theory
  3984 Finite_Set);
  3985 
  3986 * attribute [symmetric] now works for relations as well; it turns
  3987 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3988 
  3989 * induct over a !!-quantified statement (say !!x1..xn):
  3990   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3991 
  3992 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3993 %x. None. Warning: empty_def now refers to the previously hidden definition
  3994 of the empty set.
  3995 
  3996 * Algebra: formalization of classical algebra.  Intended as base for
  3997 any algebraic development in Isabelle.  Currently covers group theory
  3998 (up to Sylow's theorem) and ring theory (Universal Property of
  3999 Univariate Polynomials).  Contributions welcome;
  4000 
  4001 * GroupTheory: deleted, since its material has been moved to Algebra;
  4002 
  4003 * Complex: new directory of the complex numbers with numeric constants,
  4004 nonstandard complex numbers, and some complex analysis, standard and
  4005 nonstandard (Jacques Fleuriot);
  4006 
  4007 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4008 
  4009 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4010 Fleuriot);
  4011 
  4012 * Real/HahnBanach: updated and adapted to locales;
  4013 
  4014 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4015 Gray and Kramer);
  4016 
  4017 * UNITY: added the Meier-Sanders theory of progress sets;
  4018 
  4019 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4020 as abstract algorithms, instantiated to the JVM;
  4021 
  4022 * Bali: Java source language formalization. Type system, operational
  4023 semantics, axiomatic semantics. Supported language features:
  4024 classes, interfaces, objects,virtual methods, static methods,
  4025 static/instance fields, arrays, access modifiers, definite
  4026 assignment, exceptions.
  4027 
  4028 
  4029 *** ZF ***
  4030 
  4031 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4032 universe, etc.);
  4033 
  4034 * Main ZF: virtually all theories converted to new-style format;
  4035 
  4036 
  4037 *** ML ***
  4038 
  4039 * Pure: Tactic.prove provides sane interface for internal proofs;
  4040 omits the infamous "standard" operation, so this is more appropriate
  4041 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4042 
  4043 * Pure: improved error reporting of simprocs;
  4044 
  4045 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4046 up simprocs;
  4047 
  4048 
  4049 *** Document preparation ***
  4050 
  4051 * uses \par instead of \\ for line breaks in theory text. This may
  4052 shift some page breaks in large documents. To get the old behaviour
  4053 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4054 
  4055 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4056 other packages
  4057 
  4058 * \<euro> now needs package babel/greek instead of marvosym (which
  4059 broke \Rightarrow)
  4060 
  4061 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4062 textcomp package)
  4063 
  4064 
  4065 
  4066 New in Isabelle2002 (March 2002)
  4067 --------------------------------
  4068 
  4069 *** Document preparation ***
  4070 
  4071 * greatly simplified document preparation setup, including more
  4072 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4073 instructive isatool mkdir; users should basically be able to get
  4074 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4075 users may run a separate document processing stage manually like this:
  4076 "isatool usedir -D output HOL Test && isatool document Test/output";
  4077 
  4078 * theory dependency graph may now be incorporated into documents;
  4079 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4080 with \includegraphics of LaTeX;
  4081 
  4082 * proper spacing of consecutive markup elements, especially text
  4083 blocks after section headings;
  4084 
  4085 * support bold style (for single symbols only), input syntax is like
  4086 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4087 
  4088 * \<bullet> is now output as bold \cdot by default, which looks much
  4089 better in printed text;
  4090 
  4091 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4092 note that these symbols are currently unavailable in Proof General /
  4093 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4094 
  4095 * isatool latex no longer depends on changed TEXINPUTS, instead
  4096 isatool document copies the Isabelle style files to the target
  4097 location;
  4098 
  4099 
  4100 *** Isar ***
  4101 
  4102 * Pure/Provers: improved proof by cases and induction;
  4103   - 'case' command admits impromptu naming of parameters (such as
  4104     "case (Suc n)");
  4105   - 'induct' method divinates rule instantiation from the inductive
  4106     claim; no longer requires excessive ?P bindings for proper
  4107     instantiation of cases;
  4108   - 'induct' method properly enumerates all possibilities of set/type
  4109     rules; as a consequence facts may be also passed through *type*
  4110     rules without further ado;
  4111   - 'induct' method now derives symbolic cases from the *rulified*
  4112     rule (before it used to rulify cases stemming from the internal
  4113     atomized version); this means that the context of a non-atomic
  4114     statement becomes is included in the hypothesis, avoiding the
  4115     slightly cumbersome show "PROP ?case" form;
  4116   - 'induct' may now use elim-style induction rules without chaining
  4117     facts, using ``missing'' premises from the goal state; this allows
  4118     rules stemming from inductive sets to be applied in unstructured
  4119     scripts, while still benefitting from proper handling of non-atomic
  4120     statements; NB: major inductive premises need to be put first, all
  4121     the rest of the goal is passed through the induction;
  4122   - 'induct' proper support for mutual induction involving non-atomic
  4123     rule statements (uses the new concept of simultaneous goals, see
  4124     below);
  4125   - append all possible rule selections, but only use the first
  4126     success (no backtracking);
  4127   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4128   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4129   - added 'print_induct_rules' (covered by help item in recent Proof
  4130     General versions);
  4131   - moved induct/cases attributes to Pure, methods to Provers;
  4132   - generic method setup instantiated for FOL and HOL;
  4133 
  4134 * Pure: support multiple simultaneous goal statements, for example
  4135 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4136 meta-level mechanism, this acts as if several individual goals had
  4137 been stated separately; in particular common proof methods need to be
  4138 repeated in order to cover all claims; note that a single elimination
  4139 step is *not* sufficient to establish the two conjunctions, so this
  4140 fails:
  4141 
  4142   assume "A & B" then have A and B ..   (*".." fails*)
  4143 
  4144 better use "obtain" in situations as above; alternative refer to
  4145 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4146 
  4147 * Pure: proper integration with ``locales''; unlike the original
  4148 version by Florian Kammller, Isar locales package high-level proof
  4149 contexts rather than raw logical ones (e.g. we admit to include
  4150 attributes everywhere); operations on locales include merge and
  4151 rename; support for implicit arguments (``structures''); simultaneous
  4152 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4153 some examples;
  4154 
  4155 * Pure: the following commands have been ``localized'', supporting a
  4156 target locale specification "(in name)": 'lemma', 'theorem',
  4157 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4158 stored both within the locale and at the theory level (exported and
  4159 qualified by the locale name);
  4160 
  4161 * Pure: theory goals may now be specified in ``long'' form, with
  4162 ad-hoc contexts consisting of arbitrary locale elements. for example
  4163 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4164 definitions may be given, too); the result is a meta-level rule with
  4165 the context elements being discharged in the obvious way;
  4166 
  4167 * Pure: new proof command 'using' allows to augment currently used
  4168 facts after a goal statement ('using' is syntactically analogous to
  4169 'apply', but acts on the goal's facts only); this allows chained facts
  4170 to be separated into parts given before and after a claim, as in
  4171 ``from a and b have C using d and e <proof>'';
  4172 
  4173 * Pure: renamed "antecedent" case to "rule_context";
  4174 
  4175 * Pure: new 'judgment' command records explicit information about the
  4176 object-logic embedding (used by several tools internally); no longer
  4177 use hard-wired "Trueprop";
  4178 
  4179 * Pure: added 'corollary' command;
  4180 
  4181 * Pure: fixed 'token_translation' command;
  4182 
  4183 * Pure: removed obsolete 'exported' attribute;
  4184 
  4185 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4186 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4187 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4188 
  4189 * Pure: method 'atomize' presents local goal premises as object-level
  4190 statements (atomic meta-level propositions); setup controlled via
  4191 rewrite rules declarations of 'atomize' attribute; example
  4192 application: 'induct' method with proper rule statements in improper
  4193 proof *scripts*;
  4194 
  4195 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4196 now consider the syntactic context of assumptions, giving a better
  4197 chance to get type-inference of the arguments right (this is
  4198 especially important for locales);
  4199 
  4200 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4201 mode;
  4202 
  4203 * Pure/obtain: the formal conclusion "thesis", being marked as
  4204 ``internal'', may no longer be reference directly in the text;
  4205 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4206 situations;
  4207 
  4208 * Pure: generic 'sym' attribute which declares a rule both as pure
  4209 'elim?' and for the 'symmetric' operation;
  4210 
  4211 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4212 text; the fixed correlation with particular command syntax has been
  4213 discontinued;
  4214 
  4215 * Pure: new method 'rules' is particularly well-suited for proof
  4216 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4217 but often produces more compact proof terms with less detours;
  4218 
  4219 * Pure/Provers/classical: simplified integration with pure rule
  4220 attributes and methods; the classical "intro?/elim?/dest?"
  4221 declarations coincide with the pure ones; the "rule" method no longer
  4222 includes classically swapped intros; "intro" and "elim" methods no
  4223 longer pick rules from the context; also got rid of ML declarations
  4224 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4225 INCOMPATIBILITY;
  4226 
  4227 * Provers/classical: attribute 'swapped' produces classical inversions
  4228 of introduction rules;
  4229 
  4230 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4231 rules instead of full simplifier context; 'iff' attribute handles
  4232 conditional rules;
  4233 
  4234 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4235 
  4236 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4237 "(permissive)" option to recover old behavior;
  4238 
  4239 * HOL: 'inductive' no longer features separate (collective) attributes
  4240 for 'intros' (was found too confusing);
  4241 
  4242 * HOL: properly declared induction rules less_induct and
  4243 wf_induct_rule;
  4244 
  4245 
  4246 *** HOL ***
  4247 
  4248 * HOL: moved over to sane numeral syntax; the new policy is as
  4249 follows:
  4250 
  4251   - 0 and 1 are polymorphic constants, which are defined on any
  4252   numeric type (nat, int, real etc.);
  4253 
  4254   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4255   binary representation internally;
  4256 
  4257   - type nat has special constructor Suc, and generally prefers Suc 0
  4258   over 1::nat and Suc (Suc 0) over 2::nat;
  4259 
  4260 This change may cause significant problems of INCOMPATIBILITY; here
  4261 are some hints on converting existing sources:
  4262 
  4263   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4264   entities, so expressions involving "-" (unary or binary minus) need
  4265   to be spaced properly;
  4266 
  4267   - existing occurrences of "1" may need to be constraint "1::nat" or
  4268   even replaced by Suc 0; similar for old "2";
  4269 
  4270   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4271 
  4272   - remove all special provisions on numerals in proofs;
  4273 
  4274 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4275 representation (depends on bin_arith_simps in the default context);
  4276 
  4277 * HOL: symbolic syntax for x^2 (numeral 2);
  4278 
  4279 * HOL: the class of all HOL types is now called "type" rather than
  4280 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4281 in axclass/classes, instance/arities, and (usually rare) occurrences
  4282 in typings (of consts etc.); internally the class is called
  4283 "HOL.type", ML programs should refer to HOLogic.typeS;
  4284 
  4285 * HOL/record package improvements:
  4286   - new derived operations "fields" to build a partial record section,
  4287     "extend" to promote a fixed record to a record scheme, and
  4288     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4289     declared as simp by default;
  4290   - shared operations ("more", "fields", etc.) now need to be always
  4291     qualified) --- potential INCOMPATIBILITY;
  4292   - removed "make_scheme" operations (use "make" with "extend") --
  4293     INCOMPATIBILITY;
  4294   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4295   - provides cases/induct rules for use with corresponding Isar
  4296     methods (for concrete records, record schemes, concrete more
  4297     parts, and schematic more parts -- in that order);
  4298   - internal definitions directly based on a light-weight abstract
  4299     theory of product types over typedef rather than datatype;
  4300 
  4301 * HOL: generic code generator for generating executable ML code from
  4302 specifications; specific support for HOL constructs such as inductive
  4303 datatypes and sets, as well as recursive functions; can be invoked
  4304 via 'generate_code' theory section;
  4305 
  4306 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4307 
  4308 * HOL: consolidated and renamed several theories.  In particular:
  4309         Ord.thy has been absorbed into HOL.thy
  4310         String.thy has been absorbed into List.thy
  4311 
  4312 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4313 (beware of argument permutation!);
  4314 
  4315 * HOL: linorder_less_split superseded by linorder_cases;
  4316 
  4317 * HOL/List: "nodups" renamed to "distinct";
  4318 
  4319 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4320 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4321   - Ex_def has changed, now need to use some_eq_ex
  4322 
  4323 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4324 in this (rare) case use:
  4325 
  4326   delSWrapper "split_all_tac"
  4327   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4328 
  4329 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4330 MAY FAIL;
  4331 
  4332 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4333 Isabelle's type classes, ^ on functions and relations has too general
  4334 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4335 necessary to attach explicit type constraints;
  4336 
  4337 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4338 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4339 renamed accordingly (eg "compI" -> "rel_compI").
  4340 
  4341 * HOL: syntax translations now work properly with numerals and records
  4342 expressions;
  4343 
  4344 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4345 of "lam" -- INCOMPATIBILITY;
  4346 
  4347 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4348 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4349 renamed "Product_Type.unit";
  4350 
  4351 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4352 
  4353 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4354 the "cases" method);
  4355 
  4356 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4357 Florian Kammller);
  4358 
  4359 * HOL/IMP: updated and converted to new-style theory format; several
  4360 parts turned into readable document, with proper Isar proof texts and
  4361 some explanations (by Gerwin Klein);
  4362 
  4363 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4364 
  4365 * HOL-Hyperreal is now a logic image;
  4366 
  4367 
  4368 *** HOLCF ***
  4369 
  4370 * Isar: consts/constdefs supports mixfix syntax for continuous
  4371 operations;
  4372 
  4373 * Isar: domain package adapted to new-style theory format, e.g. see
  4374 HOLCF/ex/Dnat.thy;
  4375 
  4376 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4377 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4378 lift.induct_tac, always use UU instead of Undef;
  4379 
  4380 * HOLCF/IMP: updated and converted to new-style theory;
  4381 
  4382 
  4383 *** ZF ***
  4384 
  4385 * Isar: proper integration of logic-specific tools and packages,
  4386 including theory commands '(co)inductive', '(co)datatype',
  4387 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4388 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4389 
  4390 * theory Main no longer includes AC; for the Axiom of Choice, base
  4391 your theory on Main_ZFC;
  4392 
  4393 * the integer library now covers quotients and remainders, with many
  4394 laws relating division to addition, multiplication, etc.;
  4395 
  4396 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4397 typeless version of the formalism;
  4398 
  4399 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4400 format;
  4401 
  4402 * ZF/Induct: new directory for examples of inductive definitions,
  4403 including theory Multiset for multiset orderings; converted to
  4404 new-style theory format;
  4405 
  4406 * ZF: many new theorems about lists, ordinals, etc.;
  4407 
  4408 
  4409 *** General ***
  4410 
  4411 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4412 variable proof controls level of detail: 0 = no proofs (only oracle
  4413 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4414 also ref manual for further ML interfaces;
  4415 
  4416 * Pure/axclass: removed obsolete ML interface
  4417 goal_subclass/goal_arity;
  4418 
  4419 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4420 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4421 separate tokens, so expressions involving minus need to be spaced
  4422 properly;
  4423 
  4424 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4425 rather than "infixl" or "infixr";
  4426 
  4427 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4428 sort constraint specifications in type inference; e.g. "x::_::foo"
  4429 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4430 type variable);
  4431 
  4432 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4433 control output of nested => (types); the default behavior is
  4434 "type_brackets";
  4435 
  4436 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4437 tokens into AST constants;
  4438 
  4439 * Pure/syntax: prefer later declarations of translations and print
  4440 translation functions; potential INCOMPATIBILITY: need to reverse
  4441 multiple declarations for same syntax element constant;
  4442 
  4443 * Pure/show_hyps reset by default (in accordance to existing Isar
  4444 practice);
  4445 
  4446 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4447 addSafter;
  4448 
  4449 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4450 as well;
  4451 
  4452 * system: tested support for MacOS X; should be able to get Isabelle +
  4453 Proof General to work in a plain Terminal after installing Poly/ML
  4454 (e.g. from the Isabelle distribution area) and GNU bash alone
  4455 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4456 support requires further installations, e.g. from
  4457 http://fink.sourceforge.net/);
  4458 
  4459 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4460 
  4461 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4462 of 40 MB), cf. ML_OPTIONS;
  4463 
  4464 * system: Proof General keywords specification is now part of the
  4465 Isabelle distribution (see etc/isar-keywords.el);
  4466 
  4467 * system: support for persistent Proof General sessions (refrain from
  4468 outdating all loaded theories on startup); user may create writable
  4469 logic images like this: ``isabelle -q HOL Test'';
  4470 
  4471 * system: smart selection of Isabelle process versus Isabelle
  4472 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4473 run both "isabelle" and "Isabelle" even if file names are badly
  4474 damaged (executable inspects the case of the first letter of its own
  4475 name); added separate "isabelle-process" and "isabelle-interface";
  4476 
  4477 * system: refrain from any attempt at filtering input streams; no
  4478 longer support ``8bit'' encoding of old isabelle font, instead proper
  4479 iso-latin characters may now be used; the related isatools
  4480 "symbolinput" and "nonascii" have disappeared as well;
  4481 
  4482 * system: removed old "xterm" interface (the print modes "xterm" and
  4483 "xterm_color" are still available for direct use in a suitable
  4484 terminal);
  4485 
  4486 
  4487 
  4488 New in Isabelle99-2 (February 2001)
  4489 -----------------------------------
  4490 
  4491 *** Overview of INCOMPATIBILITIES ***
  4492 
  4493 * HOL: please note that theories in the Library and elsewhere often use the
  4494 new-style (Isar) format; to refer to their theorems in an ML script you must
  4495 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4496 
  4497 * HOL: inductive package no longer splits induction rule aggressively,
  4498 but only as far as specified by the introductions given; the old
  4499 format may be recovered via ML function complete_split_rule or attribute
  4500 'split_rule (complete)';
  4501 
  4502 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4503 gfp_Tarski to gfp_unfold;
  4504 
  4505 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4506 
  4507 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4508 relation); infix "^^" has been renamed "``"; infix "``" has been
  4509 renamed "`"; "univalent" has been renamed "single_valued";
  4510 
  4511 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4512 operation;
  4513 
  4514 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4515 
  4516 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4517 
  4518 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4519 consequence, it is no longer monotonic wrt. the local goal context
  4520 (which is now passed through the inductive cases);
  4521 
  4522 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4523 \<gg> to \<ggreater>;
  4524 
  4525 
  4526 *** Document preparation ***
  4527 
  4528 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4529 available: are "it" for near math-mode best-style output, "sl" for
  4530 slanted text style, and "tt" for plain type-writer; if no
  4531 \isabellestyle command is given, output is according to slanted
  4532 type-writer);
  4533 
  4534 * support sub/super scripts (for single symbols only), input syntax is
  4535 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4536 
  4537 * some more standard symbols; see Appendix A of the system manual for
  4538 the complete list of symbols defined in isabellesym.sty;
  4539 
  4540 * improved isabelle style files; more abstract symbol implementation
  4541 (should now use \isamath{...} and \isatext{...} in custom symbol
  4542 definitions);
  4543 
  4544 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4545 state; Note that presentation of goal states does not conform to
  4546 actual human-readable proof documents.  Please do not include goal
  4547 states into document output unless you really know what you are doing!
  4548 
  4549 * proper indentation of antiquoted output with proportional LaTeX
  4550 fonts;
  4551 
  4552 * no_document ML operator temporarily disables LaTeX document
  4553 generation;
  4554 
  4555 * isatool unsymbolize tunes sources for plain ASCII communication;
  4556 
  4557 
  4558 *** Isar ***
  4559 
  4560 * Pure: Isar now suffers initial goal statements to contain unbound
  4561 schematic variables (this does not conform to actual readable proof
  4562 documents, due to unpredictable outcome and non-compositional proof
  4563 checking); users who know what they are doing may use schematic goals
  4564 for Prolog-style synthesis of proven results;
  4565 
  4566 * Pure: assumption method (an implicit finishing) now handles actual
  4567 rules as well;
  4568 
  4569 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4570 initial goal, declare "that" only as Pure intro (only for single
  4571 steps); the "that" rule assumption may now be involved in implicit
  4572 finishing, thus ".." becomes a feasible for trivial obtains;
  4573 
  4574 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4575 instance proofs may be performed by "..";
  4576 
  4577 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4578 statements as well;
  4579 
  4580 * Pure: more robust selection of calculational rules;
  4581 
  4582 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4583 rule (as well as the assumption rule);
  4584 
  4585 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4586 lemmas, using the graph browser tool;
  4587 
  4588 * Pure: predict failure of "show" in interactive mode;
  4589 
  4590 * Pure: 'thms_containing' now takes actual terms as arguments;
  4591 
  4592 * HOL: improved method 'induct' --- now handles non-atomic goals
  4593 (potential INCOMPATIBILITY); tuned error handling;
  4594 
  4595 * HOL: cases and induct rules now provide explicit hints about the
  4596 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4597 any remaining facts are inserted into the goal verbatim;
  4598 
  4599 * HOL: local contexts (aka cases) may now contain term bindings as
  4600 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4601 the result to be shown in each case;
  4602 
  4603 * HOL: added 'recdef_tc' command;
  4604 
  4605 * isatool convert assists in eliminating legacy ML scripts;
  4606 
  4607 
  4608 *** HOL ***
  4609 
  4610 * HOL/Library: a collection of generic theories to be used together
  4611 with main HOL; the theory loader path already includes this directory
  4612 by default; the following existing theories have been moved here:
  4613 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4614 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4615 
  4616 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4617 modelling and verification task performed in Isabelle/HOL +
  4618 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4619 
  4620 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4621 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4622 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4623 'domain', this makes the theory consistent with mathematical
  4624 literature;
  4625 
  4626 * HOL basics: added overloaded operations "inverse" and "divide"
  4627 (infix "/"), syntax for generic "abs" operation, generic summation
  4628 operator \<Sum>;
  4629 
  4630 * HOL/typedef: simplified package, provide more useful rules (see also
  4631 HOL/subset.thy);
  4632 
  4633 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4634 now expressed as a proper nested rule (old-style tactic scripts may
  4635 require atomize_strip_tac to cope with non-atomic premises);
  4636 
  4637 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4638 to "split_conv" (old name still available for compatibility);
  4639 
  4640 * HOL: improved concrete syntax for strings (e.g. allows translation
  4641 rules with string literals);
  4642 
  4643 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4644  and Fleuriot's mechanization of analysis, including the transcendental
  4645  functions for the reals;
  4646 
  4647 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4648 
  4649 
  4650 *** CTT ***
  4651 
  4652 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4653 "lam" is displayed as TWO lambda-symbols
  4654 
  4655 * CTT: theory Main now available, containing everything (that is, Bool
  4656 and Arith);
  4657 
  4658 
  4659 *** General ***
  4660 
  4661 * Pure: the Simplifier has been implemented properly as a derived rule
  4662 outside of the actual kernel (at last!); the overall performance
  4663 penalty in practical applications is about 50%, while reliability of
  4664 the Isabelle inference kernel has been greatly improved;
  4665 
  4666 * print modes "brackets" and "no_brackets" control output of nested =>
  4667 (types) and ==> (props); the default behaviour is "brackets";
  4668 
  4669 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4670 as assumptions as well;
  4671 
  4672 * system: support Poly/ML 4.0;
  4673 
  4674 * system: isatool install handles KDE version 1 or 2;
  4675 
  4676 
  4677 
  4678 New in Isabelle99-1 (October 2000)
  4679 ----------------------------------
  4680 
  4681 *** Overview of INCOMPATIBILITIES ***
  4682 
  4683 * HOL: simplification of natural numbers is much changed; to partly
  4684 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4685 issue the following ML commands:
  4686 
  4687   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4688   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4689 
  4690 * HOL: simplification no longer dives into case-expressions; this is
  4691 controlled by "t.weak_case_cong" for each datatype t;
  4692 
  4693 * HOL: nat_less_induct renamed to less_induct;
  4694 
  4695 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4696 fixsome to patch .thy and .ML sources automatically;
  4697 
  4698   select_equality  -> some_equality
  4699   select_eq_Ex     -> some_eq_ex
  4700   selectI2EX       -> someI2_ex
  4701   selectI2         -> someI2
  4702   selectI          -> someI
  4703   select1_equality -> some1_equality
  4704   Eps_sym_eq       -> some_sym_eq_trivial
  4705   Eps_eq           -> some_eq_trivial
  4706 
  4707 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4708 
  4709 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4710 instead);
  4711 
  4712 * HOL: the recursion equations generated by 'recdef' are now called
  4713 f.simps instead of f.rules;
  4714 
  4715 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4716 
  4717 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4718 sometimes be needed;
  4719 
  4720 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4721 
  4722 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4723 
  4724 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4725 product is now "<*>" instead of "Times"; the lexicographic product is
  4726 now "<*lex*>" instead of "**";
  4727 
  4728 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4729 of main HOL, but was unused); better use HOL's datatype package;
  4730 
  4731 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4732 the old syntax may be recovered as follows:
  4733 
  4734   syntax (symbols)
  4735     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4736       (infixl "\\<oplus>" 100)
  4737 
  4738 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4739 
  4740 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4741 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4742 internally;
  4743 
  4744 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4745 changed from A/r to A//r;
  4746 
  4747 * ZF: new treatment of arithmetic (nat & int) may break some old
  4748 proofs;
  4749 
  4750 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4751 rulify -> rule_format, elimify -> elim_format, ...);
  4752 
  4753 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4754 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4755 should have to change intro!! to intro? only); replaced "delrule" by
  4756 "rule del";
  4757 
  4758 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4759 
  4760 * Provers: strengthened force_tac by using new first_best_tac;
  4761 
  4762 * LaTeX document preparation: several changes of isabelle.sty (see
  4763 lib/texinputs);
  4764 
  4765 
  4766 *** Document preparation ***
  4767 
  4768 * formal comments (text blocks etc.) in new-style theories may now
  4769 contain antiquotations of thm/prop/term/typ/text to be presented
  4770 according to latex print mode; concrete syntax is like this:
  4771 @{term[show_types] "f(x) = a + x"};
  4772 
  4773 * isatool mkdir provides easy setup of Isabelle session directories,
  4774 including proper document sources;
  4775 
  4776 * generated LaTeX sources are now deleted after successful run
  4777 (isatool document -c); may retain a copy somewhere else via -D option
  4778 of isatool usedir;
  4779 
  4780 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4781 style files, achieving self-contained LaTeX sources and simplifying
  4782 LaTeX debugging;
  4783 
  4784 * old-style theories now produce (crude) LaTeX output as well;
  4785 
  4786 * browser info session directories are now self-contained (may be put
  4787 on WWW server seperately); improved graphs of nested sessions; removed
  4788 graph for 'all sessions';
  4789 
  4790 * several improvements in isabelle style files; \isabellestyle{it}
  4791 produces fake math mode output; \isamarkupheader is now \section by
  4792 default; see lib/texinputs/isabelle.sty etc.;
  4793 
  4794 
  4795 *** Isar ***
  4796 
  4797 * Isar/Pure: local results and corresponding term bindings are now
  4798 subject to Hindley-Milner polymorphism (similar to ML); this
  4799 accommodates incremental type-inference very nicely;
  4800 
  4801 * Isar/Pure: new derived language element 'obtain' supports
  4802 generalized existence reasoning;
  4803 
  4804 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4805 support accumulation of results, without applying any rules yet;
  4806 useful to collect intermediate results without explicit name
  4807 references, and for use with transitivity rules with more than 2
  4808 premises;
  4809 
  4810 * Isar/Pure: scalable support for case-analysis type proofs: new
  4811 'case' language element refers to local contexts symbolically, as
  4812 produced by certain proof methods; internally, case names are attached
  4813 to theorems as "tags";
  4814 
  4815 * Isar/Pure: theory command 'hide' removes declarations from
  4816 class/type/const name spaces;
  4817 
  4818 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4819 indicate potential overloading;
  4820 
  4821 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4822 
  4823 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4824 "{a,b,c}" instead of {a,b,c};
  4825 
  4826 * Isar/Pure now provides its own version of intro/elim/dest
  4827 attributes; useful for building new logics, but beware of confusion
  4828 with the version in Provers/classical;
  4829 
  4830 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4831 case name 'antecedent';
  4832 
  4833 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4834 to the current context is now done automatically);
  4835 
  4836 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4837 for definining proof methods in ML;
  4838 
  4839 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4840 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4841 most cases, one should have to change intro!! to intro? only);
  4842 replaced "delrule" by "rule del";
  4843 
  4844 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4845 'symmetric' attribute (the latter supercedes [RS sym]);
  4846 
  4847 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4848 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4849 well (including splits);
  4850 
  4851 * Isar/Provers: Simplifier and Classical methods now support all kind
  4852 of modifiers used in the past, including 'cong', 'iff', etc.
  4853 
  4854 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4855 of Simplifier and Classical reasoner);
  4856 
  4857 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4858 now support named cases; major packages (inductive, datatype, primrec,
  4859 recdef) support case names and properly name parameters;
  4860 
  4861 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4862 monotonicity conditions are extracted to be proven at end of
  4863 calculations;
  4864 
  4865 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4866 method anyway;
  4867 
  4868 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4869 split_if split_if_asm; datatype package provides theorems foo.splits =
  4870 foo.split foo.split_asm for each datatype;
  4871 
  4872 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4873 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4874 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4875 use "(cases (simplified))" method in proper proof texts);
  4876 
  4877 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4878 
  4879 * Isar: names of theorems etc. may be natural numbers as well;
  4880 
  4881 * Isar: 'pr' command: optional arguments for goals_limit and
  4882 ProofContext.prems_limit; no longer prints theory contexts, but only
  4883 proof states;
  4884 
  4885 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4886 additional print modes to be specified; e.g. "pr(latex)" will print
  4887 proof state according to the Isabelle LaTeX style;
  4888 
  4889 * Isar: improved support for emulating tactic scripts, including proof
  4890 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4891 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4892 (for HOL datatypes);
  4893 
  4894 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4895 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4896 'proof method scripts' have to be in depth-first order;
  4897 
  4898 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4899 
  4900 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4901 should instead use individual commands for printing items
  4902 (print_commands, print_methods etc.);
  4903 
  4904 * Isar: added 'nothing' --- the empty list of theorems;
  4905 
  4906 
  4907 *** HOL ***
  4908 
  4909 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4910 corresponding virtual machine and a specification of its bytecode
  4911 verifier and a lightweight bytecode verifier, including proofs of
  4912 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4913 Cornelia Pusch (see also the homepage of project Bali at
  4914 http://isabelle.in.tum.de/Bali/);
  4915 
  4916 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4917 Clemens Ballarin;
  4918 
  4919 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4920 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4921 Rasmussen;
  4922 
  4923 * HOL/Lattice: fundamental concepts of lattice theory and order
  4924 structures, including duals, properties of bounds versus algebraic
  4925 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4926 Theorem for complete lattices etc.; may also serve as a demonstration
  4927 for abstract algebraic reasoning using axiomatic type classes, and
  4928 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4929 
  4930 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4931 von Oheimb;
  4932 
  4933 * HOL/IMPP: extension of IMP with local variables and mutually
  4934 recursive procedures, by David von Oheimb;
  4935 
  4936 * HOL/Lambda: converted into new-style theory and document;
  4937 
  4938 * HOL/ex/Multiquote: example of multiple nested quotations and
  4939 anti-quotations -- basically a generalized version of de-Bruijn
  4940 representation; very useful in avoiding lifting of operations;
  4941 
  4942 * HOL/record: added general record equality rule to simpset; fixed
  4943 select-update simplification procedure to handle extended records as
  4944 well; admit "r" as field name;
  4945 
  4946 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4947 other numeric types and also as the identity of groups, rings, etc.;
  4948 
  4949 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4950 Types nat and int belong to this axclass;
  4951 
  4952 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4953    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4954    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4955   two terms #m*u and #n*u are replaced by #(m+n)*u
  4956     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4957   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4958     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4959 
  4960 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4961 powerful prover for predicate logic but knows nothing of clasets; see
  4962 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4963 
  4964 * HOL: new version of "case_tac" subsumes both boolean case split and
  4965 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4966 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4967 
  4968 * HOL: simplification no longer dives into case-expressions: only the
  4969 selector expression is simplified, but not the remaining arms; to
  4970 enable full simplification of case-expressions for datatype t, you may
  4971 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4972 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4973 
  4974 * HOL/recdef: the recursion equations generated by 'recdef' for
  4975 function 'f' are now called f.simps instead of f.rules; if all
  4976 termination conditions are proved automatically, these simplification
  4977 rules are added to the simpset, as in primrec; rules may be named
  4978 individually as well, resulting in a separate list of theorems for
  4979 each equation;
  4980 
  4981 * HOL/While is a new theory that provides a while-combinator. It
  4982 permits the definition of tail-recursive functions without the
  4983 provision of a termination measure. The latter is necessary once the
  4984 invariant proof rule for while is applied.
  4985 
  4986 * HOL: new (overloaded) notation for the set of elements below/above
  4987 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4988 
  4989 * HOL: theorems impI, allI, ballI bound as "strip";
  4990 
  4991 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4992 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4993 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4994 
  4995 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4996 
  4997 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4998 main HOL, but was unused);
  4999 
  5000 * HOL: fewer consts declared as global (e.g. have to refer to
  5001 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5002 
  5003 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5004 in case of overlap with user translations (e.g. judgements over
  5005 tuples); (note that the underlying logical represenation is still
  5006 bogus);
  5007 
  5008 
  5009 *** ZF ***
  5010 
  5011 * ZF: simplification automatically cancels common terms in arithmetic
  5012 expressions over nat and int;
  5013 
  5014 * ZF: new treatment of nat to minimize type-checking: all operators
  5015 coerce their operands to a natural number using the function natify,
  5016 making the algebraic laws unconditional;
  5017 
  5018 * ZF: as above, for int: operators coerce their operands to an integer
  5019 using the function intify;
  5020 
  5021 * ZF: the integer library now contains many of the usual laws for the
  5022 orderings, including $<=, and monotonicity laws for $+ and $*;
  5023 
  5024 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5025 simplification;
  5026 
  5027 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5028 to the simplifier and classical reasoner simultaneously;
  5029 
  5030 
  5031 *** General ***
  5032 
  5033 * Provers: blast_tac now handles actual object-logic rules as
  5034 assumptions; note that auto_tac uses blast_tac internally as well;
  5035 
  5036 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5037 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5038 
  5039 * Provers: delrules now handles destruct rules as well (no longer need
  5040 explicit make_elim);
  5041 
  5042 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5043   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5044 use instead the strong form,
  5045   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5046 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5047 from destruct-rules;
  5048 
  5049 * Provers: Simplifier.easy_setup provides a fast path to basic
  5050 Simplifier setup for new object-logics;
  5051 
  5052 * Pure: AST translation rules no longer require constant head on LHS;
  5053 
  5054 * Pure: improved name spaces: ambiguous output is qualified; support
  5055 for hiding of names;
  5056 
  5057 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5058 XSYMBOL_HOME; no longer need to do manual configuration in most
  5059 situations;
  5060 
  5061 * system: compression of ML heaps images may now be controlled via -c
  5062 option of isabelle and isatool usedir (currently only observed by
  5063 Poly/ML);
  5064 
  5065 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5066 useful for remote X11);
  5067 
  5068 * system: provide TAGS file for Isabelle sources;
  5069 
  5070 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5071 order;
  5072 
  5073 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5074 timing flag supersedes proof_timing and Toplevel.trace;
  5075 
  5076 * ML: new combinators |>> and |>>> for incremental transformations
  5077 with secondary results (e.g. certain theory extensions):
  5078 
  5079 * ML: PureThy.add_defs gets additional argument to indicate potential
  5080 overloading (usually false);
  5081 
  5082 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5083 results;
  5084 
  5085 
  5086 
  5087 New in Isabelle99 (October 1999)
  5088 --------------------------------
  5089 
  5090 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5091 
  5092 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5093 are no longer simplified.  (This allows the simplifier to unfold recursive
  5094 functional programs.)  To restore the old behaviour, declare
  5095 
  5096     Delcongs [if_weak_cong];
  5097 
  5098 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5099 complement;
  5100 
  5101 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5102 
  5103 * HOL/datatype: mutual_induct_tac no longer exists --
  5104   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5105 
  5106 * HOL/typedef: fixed type inference for representing set; type
  5107 arguments now have to occur explicitly on the rhs as type constraints;
  5108 
  5109 * ZF: The con_defs part of an inductive definition may no longer refer
  5110 to constants declared in the same theory;
  5111 
  5112 * HOL, ZF: the function mk_cases, generated by the inductive
  5113 definition package, has lost an argument.  To simplify its result, it
  5114 uses the default simpset instead of a supplied list of theorems.
  5115 
  5116 * HOL/List: the constructors of type list are now Nil and Cons;
  5117 
  5118 * Simplifier: the type of the infix ML functions
  5119         setSSolver addSSolver setSolver addSolver
  5120 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5121 for packaging solvers. A solver is created via
  5122         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5123 where the string argument is only a comment.
  5124 
  5125 
  5126 *** Proof tools ***
  5127 
  5128 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5129 decision procedure for linear arithmetic. Currently it is used for
  5130 types `nat', `int', and `real' in HOL (see below); it can, should and
  5131 will be instantiated for other types and logics as well.
  5132 
  5133 * The simplifier now accepts rewrite rules with flexible heads, eg
  5134      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5135   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5136   matching.
  5137 
  5138 
  5139 *** General ***
  5140 
  5141 * New Isabelle/Isar subsystem provides an alternative to traditional
  5142 tactical theorem proving; together with the ProofGeneral/isar user
  5143 interface it offers an interactive environment for developing human
  5144 readable proof documents (Isar == Intelligible semi-automated
  5145 reasoning); for further information see isatool doc isar-ref,
  5146 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5147 
  5148 * improved and simplified presentation of theories: better HTML markup
  5149 (including colors), graph views in several sizes; isatool usedir now
  5150 provides a proper interface for user theories (via -P option); actual
  5151 document preparation based on (PDF)LaTeX is available as well (for
  5152 new-style theories only); see isatool doc system for more information;
  5153 
  5154 * native support for Proof General, both for classic Isabelle and
  5155 Isabelle/Isar;
  5156 
  5157 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5158 using the graph browser tool;
  5159 
  5160 * Isabelle manuals now also available as PDF;
  5161 
  5162 * theory loader rewritten from scratch (may not be fully
  5163 bug-compatible); old loadpath variable has been replaced by show_path,
  5164 add_path, del_path, reset_path functions; new operations such as
  5165 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5166 isatool doc ref);
  5167 
  5168 * improved isatool install: option -k creates KDE application icon,
  5169 option -p DIR installs standalone binaries;
  5170 
  5171 * added ML_PLATFORM setting (useful for cross-platform installations);
  5172 more robust handling of platform specific ML images for SML/NJ;
  5173 
  5174 * the settings environment is now statically scoped, i.e. it is never
  5175 created again in sub-processes invoked from isabelle, isatool, or
  5176 Isabelle;
  5177 
  5178 * path element specification '~~' refers to '$ISABELLE_HOME';
  5179 
  5180 * in locales, the "assumes" and "defines" parts may be omitted if
  5181 empty;
  5182 
  5183 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5184 long arrows);
  5185 
  5186 * new print_mode "HTML";
  5187 
  5188 * new flag show_tags controls display of tags of theorems (which are
  5189 basically just comments that may be attached by some tools);
  5190 
  5191 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5192 mode and goal output format:
  5193 
  5194 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5195 244c244
  5196 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5197 ---
  5198 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5199 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5200 181c181
  5201 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5202 ---
  5203 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5204 
  5205 * function bind_thms stores lists of theorems (cf. bind_thm);
  5206 
  5207 * new shorthand tactics ftac, eatac, datac, fatac;
  5208 
  5209 * qed (and friends) now accept "" as result name; in that case the
  5210 theorem is not stored, but proper checks and presentation of the
  5211 result still apply;
  5212 
  5213 * theorem database now also indexes constants "Trueprop", "all",
  5214 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5215 
  5216 
  5217 *** HOL ***
  5218 
  5219 ** HOL arithmetic **
  5220 
  5221 * There are now decision procedures for linear arithmetic over nat and
  5222 int:
  5223 
  5224 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5225 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5226 are treated as atomic; subformulae not involving type `nat' or `int'
  5227 are ignored; quantified subformulae are ignored unless they are
  5228 positive universal or negative existential. The tactic has to be
  5229 invoked by hand and can be a little bit slow. In particular, the
  5230 running time is exponential in the number of occurrences of `min' and
  5231 `max', and `-' on `nat'.
  5232 
  5233 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5234 (negated) (in)equalities among the premises and the conclusion into
  5235 account (i.e. no compound formulae) and does not know about `min' and
  5236 `max', and `-' on `nat'. It is fast and is used automatically by the
  5237 simplifier.
  5238 
  5239 NB: At the moment, these decision procedures do not cope with mixed
  5240 nat/int formulae where the two parts interact, such as `m < n ==>
  5241 int(m) < int(n)'.
  5242 
  5243 * HOL/Numeral provides a generic theory of numerals (encoded
  5244 efficiently as bit strings); setup for types nat/int/real is in place;
  5245 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5246 int, existing theories and proof scripts may require a few additional
  5247 type constraints;
  5248 
  5249 * integer division and remainder can now be performed on constant
  5250 arguments;
  5251 
  5252 * many properties of integer multiplication, division and remainder
  5253 are now available;
  5254 
  5255 * An interface to the Stanford Validity Checker (SVC) is available through the
  5256 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5257 are proved automatically.  SVC must be installed separately, and its results
  5258 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5259 invocation of the underlying oracle).  For SVC see
  5260   http://verify.stanford.edu/SVC
  5261 
  5262 * IsaMakefile: the HOL-Real target now builds an actual image;
  5263 
  5264 
  5265 ** HOL misc **
  5266 
  5267 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5268 (in Isabelle/Isar) -- by Gertrud Bauer;
  5269 
  5270 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5271 analysis for assembly languages with subtypes;
  5272 
  5273 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5274 -- avoids syntactic ambiguities and treats state, transition, and
  5275 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5276 changed syntax and (many) tactics;
  5277 
  5278 * HOL/inductive: Now also handles more general introduction rules such
  5279   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5280   theorems are now maintained within the theory (maintained via the
  5281   "mono" attribute);
  5282 
  5283 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5284   (using function types) such as
  5285 
  5286   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5287 
  5288 * HOL/record: record_simproc (part of the default simpset) takes care
  5289 of selectors applied to updated records; record_split_tac is no longer
  5290 part of the default claset; update_defs may now be removed from the
  5291 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5292 
  5293   claset_ref () := claset() addSWrapper record_split_wrapper;
  5294   Delsimprocs [record_simproc]
  5295 
  5296 * HOL/typedef: fixed type inference for representing set; type
  5297 arguments now have to occur explicitly on the rhs as type constraints;
  5298 
  5299 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5300 names rather than an ML expression;
  5301 
  5302 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5303 supplied later.  Program schemes can be defined, such as
  5304     "While B C s = (if B s then While B C (C s) else s)"
  5305 where the well-founded relation can be chosen after B and C have been given.
  5306 
  5307 * HOL/List: the constructors of type list are now Nil and Cons;
  5308 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5309 course, ML tools referring to List.list.op # etc. have to be adapted;
  5310 
  5311 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5312 disabled by default; run isabelle with option -m HOL to get back to
  5313 the original Gordon/HOL-style output;
  5314 
  5315 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5316 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5317 
  5318 * HOL basic syntax simplified (more orthogonal): all variants of
  5319 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5320 Eps operator is provided as well: "SOME x. P[x]";
  5321 
  5322 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5323 
  5324 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5325 thus available for user theories;
  5326 
  5327 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5328 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5329 time;
  5330 
  5331 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5332 several times and then mp;
  5333 
  5334 
  5335 *** LK ***
  5336 
  5337 * the notation <<...>> is now available as a notation for sequences of
  5338 formulas;
  5339 
  5340 * the simplifier is now installed
  5341 
  5342 * the axiom system has been generalized (thanks to Soren Heilmann)
  5343 
  5344 * the classical reasoner now has a default rule database
  5345 
  5346 
  5347 *** ZF ***
  5348 
  5349 * new primrec section allows primitive recursive functions to be given
  5350 directly (as in HOL) over datatypes and the natural numbers;
  5351 
  5352 * new tactics induct_tac and exhaust_tac for induction (or case
  5353 analysis) over datatypes and the natural numbers;
  5354 
  5355 * the datatype declaration of type T now defines the recursor T_rec;
  5356 
  5357 * simplification automatically does freeness reasoning for datatype
  5358 constructors;
  5359 
  5360 * automatic type-inference, with AddTCs command to insert new
  5361 type-checking rules;
  5362 
  5363 * datatype introduction rules are now added as Safe Introduction rules
  5364 to the claset;
  5365 
  5366 * the syntax "if P then x else y" is now available in addition to
  5367 if(P,x,y);
  5368 
  5369 
  5370 *** Internal programming interfaces ***
  5371 
  5372 * tuned simplifier trace output; new flag debug_simp;
  5373 
  5374 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5375 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5376 
  5377 * AxClass.axclass_tac lost the theory argument;
  5378 
  5379 * tuned current_goals_markers semantics: begin / end goal avoids
  5380 printing empty lines;
  5381 
  5382 * removed prs and prs_fn hook, which was broken because it did not
  5383 include \n in its semantics, forcing writeln to add one
  5384 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5385 string -> unit if you really want to output text without newline;
  5386 
  5387 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5388 plain output, interface builders may have to enable 'isabelle_font'
  5389 mode to get Isabelle font glyphs as before;
  5390 
  5391 * refined token_translation interface; INCOMPATIBILITY: output length
  5392 now of type real instead of int;
  5393 
  5394 * theory loader actions may be traced via new ThyInfo.add_hook
  5395 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5396 your own database of information attached to *whole* theories -- as
  5397 opposed to intra-theory data slots offered via TheoryDataFun;
  5398 
  5399 * proper handling of dangling sort hypotheses (at last!);
  5400 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5401 extra sort hypotheses that can be witnessed from the type signature;
  5402 the force_strip_shyps flag is gone, any remaining shyps are simply
  5403 left in the theorem (with a warning issued by strip_shyps_warning);
  5404 
  5405 
  5406 
  5407 New in Isabelle98-1 (October 1998)
  5408 ----------------------------------
  5409 
  5410 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5411 
  5412 * several changes of automated proof tools;
  5413 
  5414 * HOL: major changes to the inductive and datatype packages, including
  5415 some minor incompatibilities of theory syntax;
  5416 
  5417 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5418 called `inj_on';
  5419 
  5420 * HOL: removed duplicate thms in Arith:
  5421   less_imp_add_less  should be replaced by  trans_less_add1
  5422   le_imp_add_le      should be replaced by  trans_le_add1
  5423 
  5424 * HOL: unary minus is now overloaded (new type constraints may be
  5425 required);
  5426 
  5427 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5428 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5429 now taken as an integer constant.
  5430 
  5431 * Pure: ML function 'theory_of' renamed to 'theory';
  5432 
  5433 
  5434 *** Proof tools ***
  5435 
  5436 * Simplifier:
  5437   1. Asm_full_simp_tac is now more aggressive.
  5438      1. It will sometimes reorient premises if that increases their power to
  5439         simplify.
  5440      2. It does no longer proceed strictly from left to right but may also
  5441         rotate premises to achieve further simplification.
  5442      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5443      old Asm_full_simp_tac in that it does not rotate premises.
  5444   2. The simplifier now knows a little bit about nat-arithmetic.
  5445 
  5446 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5447 allows for selected deletion of wrappers, by introduction of names for
  5448 wrapper functionals.  This implies that addbefore, addSbefore,
  5449 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5450 and that adding two tactics with the same name overwrites the first
  5451 one (emitting a warning).
  5452   type wrapper = (int -> tactic) -> (int -> tactic)
  5453   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5454   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5455   delWrapper, delSWrapper: claset *  string            -> claset
  5456   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5457 
  5458 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5459 semantics; addbefore now affects only the unsafe part of step_tac
  5460 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5461 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5462 by Force_tac;
  5463 
  5464 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5465 compWrapper; added safe wrapper (and access functions for it);
  5466 
  5467 * HOL/split_all_tac is now much faster and fails if there is nothing
  5468 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5469 and the names of the automatically generated variables have changed.
  5470 split_all_tac has moved within claset() from unsafe wrappers to safe
  5471 wrappers, which means that !!-bound variables are split much more
  5472 aggressively, and safe_tac and clarify_tac now split such variables.
  5473 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5474 Note: the same holds for record_split_tac, which does the job of
  5475 split_all_tac for record fields.
  5476 
  5477 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5478 permanently to the default simpset using Addsplits just like
  5479 Addsimps. They can be removed via Delsplits just like
  5480 Delsimps. Lower-case versions are also available.
  5481 
  5482 * HOL/Simplifier: The rule split_if is now part of the default
  5483 simpset. This means that the simplifier will eliminate all occurrences
  5484 of if-then-else in the conclusion of a goal. To prevent this, you can
  5485 either remove split_if completely from the default simpset by
  5486 `Delsplits [split_if]' or remove it in a specific call of the
  5487 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5488 other case splitting rules to/from the default simpset: every datatype
  5489 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5490 t is the name of the datatype).
  5491 
  5492 * Classical reasoner / Simplifier combination: new force_tac (and
  5493 derivatives Force_tac, force) combines rewriting and classical
  5494 reasoning (and whatever other tools) similarly to auto_tac, but is
  5495 aimed to solve the given subgoal completely.
  5496 
  5497 
  5498 *** General ***
  5499 
  5500 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5501 and `goalw': the theory is no longer needed as an explicit argument -
  5502 the current theory context is used; assumptions are no longer returned
  5503 at the ML-level unless one of them starts with ==> or !!; it is
  5504 recommended to convert to these new commands using isatool fixgoal
  5505 (backup your sources first!);
  5506 
  5507 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5508 the current theory context, and 'theory' to lookup stored theories;
  5509 
  5510 * new theory section 'locale' for declaring constants, assumptions and
  5511 definitions that have local scope;
  5512 
  5513 * new theory section 'nonterminals' for purely syntactic types;
  5514 
  5515 * new theory section 'setup' for generic ML setup functions
  5516 (e.g. package initialization);
  5517 
  5518 * the distribution now includes Isabelle icons: see
  5519 lib/logo/isabelle-{small,tiny}.xpm;
  5520 
  5521 * isatool install - install binaries with absolute references to
  5522 ISABELLE_HOME/bin;
  5523 
  5524 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5525 
  5526 * print mode 'emacs' reserved for Isamode;
  5527 
  5528 * support multiple print (ast) translations per constant name;
  5529 
  5530 * theorems involving oracles are now printed with a suffixed [!];
  5531 
  5532 
  5533 *** HOL ***
  5534 
  5535 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5536 
  5537 * HOL/inductive package reorganized and improved: now supports mutual
  5538 definitions such as
  5539 
  5540   inductive EVEN ODD
  5541     intrs
  5542       null "0 : EVEN"
  5543       oddI "n : EVEN ==> Suc n : ODD"
  5544       evenI "n : ODD ==> Suc n : EVEN"
  5545 
  5546 new theorem list "elims" contains an elimination rule for each of the
  5547 recursive sets; inductive definitions now handle disjunctive premises
  5548 correctly (also ZF);
  5549 
  5550 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5551 "mutual_induct" no longer exists - the induction rule is always
  5552 contained in "induct";
  5553 
  5554 
  5555 * HOL/datatype package re-implemented and greatly improved: now
  5556 supports mutually recursive datatypes such as
  5557 
  5558   datatype
  5559     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5560             | SUM ('a aexp) ('a aexp)
  5561             | DIFF ('a aexp) ('a aexp)
  5562             | NUM 'a
  5563   and
  5564     'a bexp = LESS ('a aexp) ('a aexp)
  5565             | AND ('a bexp) ('a bexp)
  5566             | OR ('a bexp) ('a bexp)
  5567 
  5568 as well as indirectly recursive datatypes such as
  5569 
  5570   datatype
  5571     ('a, 'b) term = Var 'a
  5572                   | App 'b ((('a, 'b) term) list)
  5573 
  5574 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5575 induction on mutually / indirectly recursive datatypes.
  5576 
  5577 Primrec equations are now stored in theory and can be accessed via
  5578 <function_name>.simps.
  5579 
  5580 INCOMPATIBILITIES:
  5581 
  5582   - Theories using datatypes must now have theory Datatype as an
  5583     ancestor.
  5584   - The specific <typename>.induct_tac no longer exists - use the
  5585     generic induct_tac instead.
  5586   - natE has been renamed to nat.exhaust - use exhaust_tac
  5587     instead of res_inst_tac ... natE. Note that the variable
  5588     names in nat.exhaust differ from the names in natE, this
  5589     may cause some "fragile" proofs to fail.
  5590   - The theorems split_<typename>_case and split_<typename>_case_asm
  5591     have been renamed to <typename>.split and <typename>.split_asm.
  5592   - Since default sorts of type variables are now handled correctly,
  5593     some datatype definitions may have to be annotated with explicit
  5594     sort constraints.
  5595   - Primrec definitions no longer require function name and type
  5596     of recursive argument.
  5597 
  5598 Consider using isatool fixdatatype to adapt your theories and proof
  5599 scripts to the new package (backup your sources first!).
  5600 
  5601 
  5602 * HOL/record package: considerably improved implementation; now
  5603 includes concrete syntax for record types, terms, updates; theorems
  5604 for surjective pairing and splitting !!-bound record variables; proof
  5605 support is as follows:
  5606 
  5607   1) standard conversions (selectors or updates applied to record
  5608 constructor terms) are part of the standard simpset;
  5609 
  5610   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5611 made part of standard simpset and claset via addIffs;
  5612 
  5613   3) a tactic for record field splitting (record_split_tac) is part of
  5614 the standard claset (addSWrapper);
  5615 
  5616 To get a better idea about these rules you may retrieve them via
  5617 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5618 the name of your record type.
  5619 
  5620 The split tactic 3) conceptually simplifies by the following rule:
  5621 
  5622   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5623 
  5624 Thus any record variable that is bound by meta-all will automatically
  5625 blow up into some record constructor term, consequently the
  5626 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5627 solve record problems automatically.
  5628 
  5629 
  5630 * reorganized the main HOL image: HOL/Integ and String loaded by
  5631 default; theory Main includes everything;
  5632 
  5633 * automatic simplification of integer sums and comparisons, using cancellation;
  5634 
  5635 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5636 
  5637 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5638 
  5639 * many new identities for unions, intersections, set difference, etc.;
  5640 
  5641 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5642 called split_if, split_split, split_sum_case and split_nat_case (to go
  5643 with add/delsplits);
  5644 
  5645 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5646 (?x::unit) = (); this is made part of the default simpset, which COULD
  5647 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5648 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5649 unit_abs_eta_conv is added in order to counter the effect of
  5650 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5651 %u.f();
  5652 
  5653 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5654 makes more sense);
  5655 
  5656 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5657   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5658   disjointness reasoning but breaking a few old proofs.
  5659 
  5660 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5661 to 'converse' from 'inverse' (for compatibility with ZF and some
  5662 literature);
  5663 
  5664 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5665 the well-founded relation;
  5666 
  5667 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5668     Compl A.  The "Compl" syntax remains available as input syntax for this
  5669     release ONLY.
  5670 
  5671 * HOL/Update: new theory of function updates:
  5672     f(a:=b) == %x. if x=a then b else f x
  5673 may also be iterated as in f(a:=b,c:=d,...);
  5674 
  5675 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5676 
  5677 * HOL/List:
  5678   - new function list_update written xs[i:=v] that updates the i-th
  5679     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5680   - new function `upt' written [i..j(] which generates the list
  5681     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5682     bound write [i..j], which is a shorthand for [i..j+1(].
  5683   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5684 
  5685 * HOL/Arith:
  5686   - removed 'pred' (predecessor) function;
  5687   - generalized some theorems about n-1;
  5688   - many new laws about "div" and "mod";
  5689   - new laws about greatest common divisors (see theory ex/Primes);
  5690 
  5691 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5692 instead of "inverse";
  5693 
  5694 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5695   of the multiset ordering;
  5696 
  5697 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5698   (not included by default);
  5699 
  5700 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5701 
  5702 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5703   programs, i.e. different program variables may have different types.
  5704 
  5705 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5706   [previously, this check worked only if the rewrite rule was unconditional]
  5707   Now rew can involve either definitions or equalities (either == or =).
  5708 
  5709 
  5710 *** ZF ***
  5711 
  5712 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5713   only the theorems proved on ZF.ML;
  5714 
  5715 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5716   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5717   disjointness reasoning but breaking a few old proofs.
  5718 
  5719 * ZF/Update: new theory of function updates
  5720     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5721   may also be iterated as in f(a:=b,c:=d,...);
  5722 
  5723 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5724 
  5725 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5726   [previously, this check worked only if the rewrite rule was unconditional]
  5727   Now rew can involve either definitions or equalities (either == or =).
  5728 
  5729 * case_tac provided for compatibility with HOL
  5730     (like the old excluded_middle_tac, but with subgoals swapped)
  5731 
  5732 
  5733 *** Internal programming interfaces ***
  5734 
  5735 * Pure: several new basic modules made available for general use, see
  5736 also src/Pure/README;
  5737 
  5738 * improved the theory data mechanism to support encapsulation (data
  5739 kind name replaced by private Object.kind, acting as authorization
  5740 key); new type-safe user interface via functor TheoryDataFun; generic
  5741 print_data function becomes basically useless;
  5742 
  5743 * removed global_names compatibility flag -- all theory declarations
  5744 are qualified by default;
  5745 
  5746 * module Pure/Syntax now offers quote / antiquote translation
  5747 functions (useful for Hoare logic etc. with implicit dependencies);
  5748 see HOL/ex/Antiquote for an example use;
  5749 
  5750 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5751 cterm -> thm;
  5752 
  5753 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5754 subgoal;
  5755 
  5756 * Display.print_goals function moved to Locale.print_goals;
  5757 
  5758 * standard print function for goals supports current_goals_markers
  5759 variable for marking begin of proof, end of proof, start of goal; the
  5760 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5761 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5762 for example;
  5763 
  5764 
  5765 
  5766 New in Isabelle98 (January 1998)
  5767 --------------------------------
  5768 
  5769 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5770 
  5771 * changed lexical syntax of terms / types: dots made part of long
  5772 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5773 
  5774 * simpset (and claset) reference variable replaced by functions
  5775 simpset / simpset_ref;
  5776 
  5777 * no longer supports theory aliases (via merge) and non-trivial
  5778 implicit merge of thms' signatures;
  5779 
  5780 * most internal names of constants changed due to qualified names;
  5781 
  5782 * changed Pure/Sequence interface (see Pure/seq.ML);
  5783 
  5784 
  5785 *** General Changes ***
  5786 
  5787 * hierachically structured name spaces (for consts, types, axms, thms
  5788 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5789 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5790 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5791 long_names for fully qualified output names; NOTE: ML programs
  5792 (special tactics, packages etc.) referring to internal names may have
  5793 to be adapted to cope with fully qualified names; in case of severe
  5794 backward campatibility problems try setting 'global_names' at compile
  5795 time to have enrything declared within a flat name space; one may also
  5796 fine tune name declarations in theories via the 'global' and 'local'
  5797 section;
  5798 
  5799 * reimplemented the implicit simpset and claset using the new anytype
  5800 data filed in signatures; references simpset:simpset ref etc. are
  5801 replaced by functions simpset:unit->simpset and
  5802 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5803 to patch your ML files accordingly;
  5804 
  5805 * HTML output now includes theory graph data for display with Java
  5806 applet or isatool browser; data generated automatically via isatool
  5807 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5808 
  5809 * defs may now be conditional; improved rewrite_goals_tac to handle
  5810 conditional equations;
  5811 
  5812 * defs now admits additional type arguments, using TYPE('a) syntax;
  5813 
  5814 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5815 creates a new theory node; implicit merge of thms' signatures is
  5816 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5817 transfer:theory->thm->thm in (rare) cases;
  5818 
  5819 * improved handling of draft signatures / theories; draft thms (and
  5820 ctyps, cterms) are automatically promoted to real ones;
  5821 
  5822 * slightly changed interfaces for oracles: admit many per theory, named
  5823 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5824 
  5825 * print_goals: optional output of const types (set show_consts and
  5826 show_types);
  5827 
  5828 * improved output of warnings (###) and errors (***);
  5829 
  5830 * subgoal_tac displays a warning if the new subgoal has type variables;
  5831 
  5832 * removed old README and Makefiles;
  5833 
  5834 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5835 
  5836 * removed obsolete init_pps and init_database;
  5837 
  5838 * deleted the obsolete tactical STATE, which was declared by
  5839     fun STATE tacfun st = tacfun st st;
  5840 
  5841 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5842 (which abbreviates $HOME);
  5843 
  5844 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5845 use isatool fixseq to adapt your ML programs (this works for fully
  5846 qualified references to the Sequence structure only!);
  5847 
  5848 * use_thy no longer requires writable current directory; it always
  5849 reloads .ML *and* .thy file, if either one is out of date;
  5850 
  5851 
  5852 *** Classical Reasoner ***
  5853 
  5854 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5855 tactics that use classical reasoning to simplify a subgoal without
  5856 splitting it into several subgoals;
  5857 
  5858 * Safe_tac: like safe_tac but uses the default claset;
  5859 
  5860 
  5861 *** Simplifier ***
  5862 
  5863 * added simplification meta rules:
  5864     (asm_)(full_)simplify: simpset -> thm -> thm;
  5865 
  5866 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5867 logics (again);
  5868 
  5869 * added prems argument to simplification procedures;
  5870 
  5871 * HOL, FOL, ZF: added infix function `addsplits':
  5872   instead of `<simpset> setloop (split_tac <thms>)'
  5873   you can simply write `<simpset> addsplits <thms>'
  5874 
  5875 
  5876 *** Syntax ***
  5877 
  5878 * TYPE('a) syntax for type reflection terms;
  5879 
  5880 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5881 
  5882 * pretty printer: changed order of mixfix annotation preference (again!);
  5883 
  5884 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5885 
  5886 
  5887 *** HOL ***
  5888 
  5889 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5890   with `addloop' of the simplifier to faciliate case splitting in premises.
  5891 
  5892 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5893 
  5894 * HOL/Auth: new protocol proofs including some for the Internet
  5895   protocol TLS;
  5896 
  5897 * HOL/Map: new theory of `maps' a la VDM;
  5898 
  5899 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5900 cancelling out common nat summands from =, <, <= (in)equalities, or
  5901 differences; simplification procedures nat_cancel_factor for
  5902 cancelling common factor from =, <, <= (in)equalities over natural
  5903 sums; nat_cancel contains both kinds of procedures, it is installed by
  5904 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5905 
  5906 * HOL/simplifier: terms of the form
  5907   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5908   are rewritten to
  5909   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5910   and those of the form
  5911   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5912   are rewritten to
  5913   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5914 
  5915 * HOL/datatype
  5916   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5917 
  5918   P(t_case f1 ... fn x) =
  5919      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5920         ...
  5921        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5922      )
  5923 
  5924   and a theorem `split_t_case_asm' of the form
  5925 
  5926   P(t_case f1 ... fn x) =
  5927     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5928         ...
  5929        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5930      )
  5931   which can be added to a simpset via `addsplits'. The existing theorems
  5932   expand_list_case and expand_option_case have been renamed to
  5933   split_list_case and split_option_case.
  5934 
  5935 * HOL/Arithmetic:
  5936   - `pred n' is automatically converted to `n-1'.
  5937     Users are strongly encouraged not to use `pred' any longer,
  5938     because it will disappear altogether at some point.
  5939   - Users are strongly encouraged to write "0 < n" rather than
  5940     "n ~= 0". Theorems and proof tools have been modified towards this
  5941     `standard'.
  5942 
  5943 * HOL/Lists:
  5944   the function "set_of_list" has been renamed "set" (and its theorems too);
  5945   the function "nth" now takes its arguments in the reverse order and
  5946   has acquired the infix notation "!" as in "xs!n".
  5947 
  5948 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5949 
  5950 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5951   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5952 
  5953 * HOL/record: extensible records with schematic structural subtyping
  5954 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5955 still lacks various theorems and concrete record syntax;
  5956 
  5957 
  5958 *** HOLCF ***
  5959 
  5960 * removed "axioms" and "generated by" sections;
  5961 
  5962 * replaced "ops" section by extended "consts" section, which is capable of
  5963   handling the continuous function space "->" directly;
  5964 
  5965 * domain package:
  5966   . proves theorems immediately and stores them in the theory,
  5967   . creates hierachical name space,
  5968   . now uses normal mixfix annotations (instead of cinfix...),
  5969   . minor changes to some names and values (for consistency),
  5970   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5971   . separator between mutual domain defs: changed "," to "and",
  5972   . improved handling of sort constraints;  now they have to
  5973     appear on the left-hand side of the equations only;
  5974 
  5975 * fixed LAM <x,y,zs>.b syntax;
  5976 
  5977 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5978 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5979 
  5980 
  5981 *** FOL and ZF ***
  5982 
  5983 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5984   with `addloop' of the simplifier to faciliate case splitting in premises.
  5985 
  5986 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5987 in HOL, they strip ALL and --> from proved theorems;
  5988 
  5989 
  5990 
  5991 New in Isabelle94-8 (May 1997)
  5992 ------------------------------
  5993 
  5994 *** General Changes ***
  5995 
  5996 * new utilities to build / run / maintain Isabelle etc. (in parts
  5997 still somewhat experimental); old Makefiles etc. still functional;
  5998 
  5999 * new 'Isabelle System Manual';
  6000 
  6001 * INSTALL text, together with ./configure and ./build scripts;
  6002 
  6003 * reimplemented type inference for greater efficiency, better error
  6004 messages and clean internal interface;
  6005 
  6006 * prlim command for dealing with lots of subgoals (an easier way of
  6007 setting goals_limit);
  6008 
  6009 
  6010 *** Syntax ***
  6011 
  6012 * supports alternative (named) syntax tables (parser and pretty
  6013 printer); internal interface is provided by add_modesyntax(_i);
  6014 
  6015 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6016 be used in conjunction with the Isabelle symbol font; uses the
  6017 "symbols" syntax table;
  6018 
  6019 * added token_translation interface (may translate name tokens in
  6020 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6021 the current print_mode); IMPORTANT: user print translation functions
  6022 are responsible for marking newly introduced bounds
  6023 (Syntax.mark_boundT);
  6024 
  6025 * token translations for modes "xterm" and "xterm_color" that display
  6026 names in bold, underline etc. or colors (which requires a color
  6027 version of xterm);
  6028 
  6029 * infixes may now be declared with names independent of their syntax;
  6030 
  6031 * added typed_print_translation (like print_translation, but may
  6032 access type of constant);
  6033 
  6034 
  6035 *** Classical Reasoner ***
  6036 
  6037 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6038 some limitations.  Blast_tac...
  6039   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6040   + ignores elimination rules that don't have the correct format
  6041         (the conclusion MUST be a formula variable)
  6042   + ignores types, which can make HOL proofs fail
  6043   + rules must not require higher-order unification, e.g. apply_type in ZF
  6044     [message "Function Var's argument not a bound variable" relates to this]
  6045   + its proof strategy is more general but can actually be slower
  6046 
  6047 * substitution with equality assumptions no longer permutes other
  6048 assumptions;
  6049 
  6050 * minor changes in semantics of addafter (now called addaltern); renamed
  6051 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6052 (and access functions for it);
  6053 
  6054 * improved combination of classical reasoner and simplifier:
  6055   + functions for handling clasimpsets
  6056   + improvement of addss: now the simplifier is called _after_ the
  6057     safe steps.
  6058   + safe variant of addss called addSss: uses safe simplifications
  6059     _during_ the safe steps. It is more complete as it allows multiple
  6060     instantiations of unknowns (e.g. with slow_tac).
  6061 
  6062 *** Simplifier ***
  6063 
  6064 * added interface for simplification procedures (functions that
  6065 produce *proven* rewrite rules on the fly, depending on current
  6066 redex);
  6067 
  6068 * ordering on terms as parameter (used for ordered rewriting);
  6069 
  6070 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6071 
  6072 * the solver is now split into a safe and an unsafe part.
  6073 This should be invisible for the normal user, except that the
  6074 functions setsolver and addsolver have been renamed to setSolver and
  6075 addSolver; added safe_asm_full_simp_tac;
  6076 
  6077 
  6078 *** HOL ***
  6079 
  6080 * a generic induction tactic `induct_tac' which works for all datatypes and
  6081 also for type `nat';
  6082 
  6083 * a generic case distinction tactic `exhaust_tac' which works for all
  6084 datatypes and also for type `nat';
  6085 
  6086 * each datatype comes with a function `size';
  6087 
  6088 * patterns in case expressions allow tuple patterns as arguments to
  6089 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6090 
  6091 * primrec now also works with type nat;
  6092 
  6093 * recdef: a new declaration form, allows general recursive functions to be
  6094 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6095 
  6096 * the constant for negation has been renamed from "not" to "Not" to
  6097 harmonize with FOL, ZF, LK, etc.;
  6098 
  6099 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6100 infinite lists;
  6101 
  6102 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6103 
  6104 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6105 problems in commutative rings, using axiomatic type classes for + and *;
  6106 
  6107 * more examples in HOL/MiniML and HOL/Auth;
  6108 
  6109 * more default rewrite rules for quantifiers, union/intersection;
  6110 
  6111 * a new constant `arbitrary == @x.False';
  6112 
  6113 * HOLCF/IOA replaces old HOL/IOA;
  6114 
  6115 * HOLCF changes: derived all rules and arities
  6116   + axiomatic type classes instead of classes
  6117   + typedef instead of faking type definitions
  6118   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6119   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6120   + eliminated the types void, one, tr
  6121   + use unit lift and bool lift (with translations) instead of one and tr
  6122   + eliminated blift from Lift3.thy (use Def instead of blift)
  6123   all eliminated rules are derived as theorems --> no visible changes ;
  6124 
  6125 
  6126 *** ZF ***
  6127 
  6128 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6129 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6130 as ZF_cs addSIs [equalityI];
  6131 
  6132 
  6133 
  6134 New in Isabelle94-7 (November 96)
  6135 ---------------------------------
  6136 
  6137 * allowing negative levels (as offsets) in prlev and choplev;
  6138 
  6139 * super-linear speedup for large simplifications;
  6140 
  6141 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6142 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6143 FAIL); can suppress it using the command Delsimps (ex_simps @
  6144 all_simps); De Morgan laws are also now included, by default;
  6145 
  6146 * improved printing of ==>  :  ~:
  6147 
  6148 * new object-logic "Sequents" adds linear logic, while replacing LK
  6149 and Modal (thanks to Sara Kalvala);
  6150 
  6151 * HOL/Auth: correctness proofs for authentication protocols;
  6152 
  6153 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6154 examples on HOL/Auth);
  6155 
  6156 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6157 the rewriter and classical reasoner simultaneously;
  6158 
  6159 * function uresult no longer returns theorems in "standard" format;
  6160 regain previous version by: val uresult = standard o uresult;
  6161 
  6162 
  6163 
  6164 New in Isabelle94-6
  6165 -------------------
  6166 
  6167 * oracles -- these establish an interface between Isabelle and trusted
  6168 external reasoners, which may deliver results as theorems;
  6169 
  6170 * proof objects (in particular record all uses of oracles);
  6171 
  6172 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6173 
  6174 * "constdefs" section in theory files;
  6175 
  6176 * "primrec" section (HOL) no longer requires names;
  6177 
  6178 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6179 
  6180 
  6181 
  6182 New in Isabelle94-5
  6183 -------------------
  6184 
  6185 * reduced space requirements;
  6186 
  6187 * automatic HTML generation from theories;
  6188 
  6189 * theory files no longer require "..." (quotes) around most types;
  6190 
  6191 * new examples, including two proofs of the Church-Rosser theorem;
  6192 
  6193 * non-curried (1994) version of HOL is no longer distributed;
  6194 
  6195 
  6196 
  6197 New in Isabelle94-4
  6198 -------------------
  6199 
  6200 * greatly reduced space requirements;
  6201 
  6202 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6203 
  6204 * searchable theorem database (see the section "Retrieving theorems" on
  6205 page 8 of the Reference Manual);
  6206 
  6207 * new examples, including Grabczewski's monumental case study of the
  6208 Axiom of Choice;
  6209 
  6210 * The previous version of HOL renamed to Old_HOL;
  6211 
  6212 * The new version of HOL (previously called CHOL) uses a curried syntax
  6213 for functions.  Application looks like f a b instead of f(a,b);
  6214 
  6215 * Mutually recursive inductive definitions finally work in HOL;
  6216 
  6217 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6218 translates to the operator "split";
  6219 
  6220 
  6221 
  6222 New in Isabelle94-3
  6223 -------------------
  6224 
  6225 * new infix operator, addss, allowing the classical reasoner to
  6226 perform simplification at each step of its search.  Example:
  6227         fast_tac (cs addss ss)
  6228 
  6229 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6230 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6231 look like (a,b) instead of <a,b>;
  6232 
  6233 * PLEASE NOTE: CHOL will eventually replace HOL!
  6234 
  6235 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6236 It translates to the operator "split".  A new theory of integers is available;
  6237 
  6238 * In ZF, integer numerals now denote two's-complement binary integers.
  6239 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6240 
  6241 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6242 of the Axiom of Choice;
  6243 
  6244 
  6245 
  6246 New in Isabelle94-2
  6247 -------------------
  6248 
  6249 * Significantly faster resolution;
  6250 
  6251 * the different sections in a .thy file can now be mixed and repeated
  6252 freely;
  6253 
  6254 * Database of theorems for FOL, HOL and ZF.  New
  6255 commands including qed, qed_goal and bind_thm store theorems in the database.
  6256 
  6257 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6258 a given theory (thms_of), or find out what theory a theorem was proved in
  6259 (theory_of_thm);
  6260 
  6261 * Bugs fixed in the inductive definition and datatype packages;