NEWS
author haftmann
Fri Apr 17 15:57:26 2009 +0200 (2009-04-17)
changeset 30949 37f887b55e7f
parent 30930 11010e5f18f0
child 30951 a6e26a248f03
permissions -rw-r--r--
separated funpow, relpow from power on monoids
     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 * Power operation on relations and functions is now a dedicated overloaded constant
    13 funpower with infix syntax "^^".  INCOMPATIBILITY.
    14 
    15 New in Isabelle2009 (April 2009)
    16 --------------------------------
    17 
    18 *** General ***
    19 
    20 * Simplified main Isabelle executables, with less surprises on
    21 case-insensitive file-systems (such as Mac OS).
    22 
    23   - The main Isabelle tool wrapper is now called "isabelle" instead of
    24     "isatool."
    25 
    26   - The former "isabelle" alias for "isabelle-process" has been
    27     removed (should rarely occur to regular users).
    28 
    29   - The former "isabelle-interface" and its alias "Isabelle" have been
    30     removed (interfaces are now regular Isabelle tools).
    31 
    32 Within scripts and make files, the Isabelle environment variables
    33 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    34 respectively.  (The latter are still available as legacy feature.)
    35 
    36 The old isabelle-interface wrapper could react in confusing ways if
    37 the interface was uninstalled or changed otherwise.  Individual
    38 interface tool configuration is now more explicit, see also the
    39 Isabelle system manual.  In particular, Proof General is now available
    40 via "isabelle emacs".
    41 
    42 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    43 purge installed copies of Isabelle executables and re-run "isabelle
    44 install -p ...", or use symlinks.
    45 
    46 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    47 old ~/isabelle, which was slightly non-standard and apt to cause
    48 surprises on case-insensitive file-systems (such as Mac OS).
    49 
    50 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    51 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    52 care is required when using older releases of Isabelle.  Note that
    53 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    54 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
    55 
    56 * Proofs of fully specified statements are run in parallel on
    57 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
    58 a regular 4-core machine, if the initial heap space is made reasonably
    59 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
    60 
    61 * The main reference manuals ("isar-ref", "implementation", and
    62 "system") have been updated and extended.  Formally checked references
    63 as hyperlinks are now available uniformly.
    64 
    65 
    66 *** Pure ***
    67 
    68 * Complete re-implementation of locales.  INCOMPATIBILITY in several
    69 respects.  The most important changes are listed below.  See the
    70 Tutorial on Locales ("locales" manual) for details.
    71 
    72 - In locale expressions, instantiation replaces renaming.  Parameters
    73 must be declared in a for clause.  To aid compatibility with previous
    74 parameter inheritance, in locale declarations, parameters that are not
    75 'touched' (instantiation position "_" or omitted) are implicitly added
    76 with their syntax at the beginning of the for clause.
    77 
    78 - Syntax from abbreviations and definitions in locales is available in
    79 locale expressions and context elements.  The latter is particularly
    80 useful in locale declarations.
    81 
    82 - More flexible mechanisms to qualify names generated by locale
    83 expressions.  Qualifiers (prefixes) may be specified in locale
    84 expressions, and can be marked as mandatory (syntax: "name!:") or
    85 optional (syntax "name?:").  The default depends for plain "name:"
    86 depends on the situation where a locale expression is used: in
    87 commands 'locale' and 'sublocale' prefixes are optional, in
    88 'interpretation' and 'interpret' prefixes are mandatory.  The old
    89 implicit qualifiers derived from the parameter names of a locale are
    90 no longer generated.
    91 
    92 - Command "sublocale l < e" replaces "interpretation l < e".  The
    93 instantiation clause in "interpretation" and "interpret" (square
    94 brackets) is no longer available.  Use locale expressions.
    95 
    96 - When converting proof scripts, mandatory qualifiers in
    97 'interpretation' and 'interpret' should be retained by default, even
    98 if this is an INCOMPATIBILITY compared to former behavior.  In the
    99 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   100 in locale expressions range over a single locale instance only.
   101 
   102 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   103 In existing theorem specifications replace the includes element by the
   104 respective context elements of the included locale, omitting those
   105 that are already present in the theorem specification.  Multiple
   106 assume elements of a locale should be replaced by a single one
   107 involving the locale predicate.  In the proof body, declarations (most
   108 notably theorems) may be regained by interpreting the respective
   109 locales in the proof context as required (command "interpret").
   110 
   111 If using "includes" in replacement of a target solely because the
   112 parameter types in the theorem are not as general as in the target,
   113 consider declaring a new locale with additional type constraints on
   114 the parameters (context element "constrains").
   115 
   116 - Discontinued "locale (open)".  INCOMPATIBILITY.
   117 
   118 - Locale interpretation commands no longer attempt to simplify goal.
   119 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   120 methods intro_locales and unfold_locales to clarify.
   121 
   122 - Locale interpretation commands no longer accept interpretation
   123 attributes.  INCOMPATIBILITY.
   124 
   125 * Class declaration: so-called "base sort" must not be given in import
   126 list any longer, but is inferred from the specification.  Particularly
   127 in HOL, write
   128 
   129     class foo = ...
   130 
   131 instead of
   132 
   133     class foo = type + ...
   134 
   135 * Class target: global versions of theorems stemming do not carry a
   136 parameter prefix any longer.  INCOMPATIBILITY.
   137 
   138 * Class 'instance' command no longer accepts attached definitions.
   139 INCOMPATIBILITY, use proper 'instantiation' target instead.
   140 
   141 * Recovered hiding of consts, which was accidentally broken in
   142 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   143 makes c inaccessible; consider using ``hide (open) const c'' instead.
   144 
   145 * Slightly more coherent Pure syntax, with updated documentation in
   146 isar-ref manual.  Removed locales meta_term_syntax and
   147 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   148 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   149 directly in regular applications.
   150 
   151 * There is a new syntactic category "float_const" for signed decimal
   152 fractions (e.g. 123.45 or -123.45).
   153 
   154 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   155 interface with 'setup' command instead.
   156 
   157 * Command 'local_setup' is similar to 'setup', but operates on a local
   158 theory context.
   159 
   160 * The 'axiomatization' command now only works within a global theory
   161 context.  INCOMPATIBILITY.
   162 
   163 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   164 hypotheses.  Sorts required in the course of reasoning need to be
   165 covered by the constraints in the initial statement, completed by the
   166 type instance information of the background theory.  Non-trivial sort
   167 hypotheses, which rarely occur in practice, may be specified via
   168 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   169 
   170   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   171 
   172 The result contains an implicit sort hypotheses as before --
   173 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   174 normalization.
   175 
   176 * Generalized Isar history, with support for linear undo, direct state
   177 addressing etc.
   178 
   179 * Changed defaults for unify configuration options:
   180 
   181   unify_trace_bound = 50 (formerly 25)
   182   unify_search_bound = 60 (formerly 30)
   183 
   184 * Different bookkeeping for code equations (INCOMPATIBILITY):
   185 
   186   a) On theory merge, the last set of code equations for a particular
   187      constant is taken (in accordance with the policy applied by other
   188      parts of the code generator framework).
   189 
   190   b) Code equations stemming from explicit declarations (e.g. code
   191      attribute) gain priority over default code equations stemming
   192      from definition, primrec, fun etc.
   193 
   194 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   195 
   196 * Unified theorem tables for both code code generators.  Thus [code
   197 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   198 
   199 * Command 'find_consts' searches for constants based on type and name
   200 patterns, e.g.
   201 
   202     find_consts "_ => bool"
   203 
   204 By default, matching is against subtypes, but it may be restricted to
   205 the whole type.  Searching by name is possible.  Multiple queries are
   206 conjunctive and queries may be negated by prefixing them with a
   207 hyphen:
   208 
   209     find_consts strict: "_ => bool" name: "Int" -"int => int"
   210 
   211 * New 'find_theorems' criterion "solves" matches theorems that
   212 directly solve the current goal (modulo higher-order unification).
   213 
   214 * Auto solve feature for main theorem statements: whenever a new goal
   215 is stated, "find_theorems solves" is called; any theorems that could
   216 solve the lemma directly are listed as part of the goal state.
   217 Cf. associated options in Proof General Isabelle settings menu,
   218 enabled by default, with reasonable timeout for pathological cases of
   219 higher-order unification.
   220 
   221 
   222 *** Document preparation ***
   223 
   224 * Antiquotation @{lemma} now imitates a regular terminal proof,
   225 demanding keyword 'by' and supporting the full method expression
   226 syntax just like the Isar command 'by'.
   227 
   228 
   229 *** HOL ***
   230 
   231 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   232 points Main and Complex_Main remain as before.
   233 
   234 * Logic image HOL-Plain provides a minimal HOL with the most important
   235 tools available (inductive, datatype, primrec, ...).  This facilitates
   236 experimentation and tool development.  Note that user applications
   237 (and library theories) should never refer to anything below theory
   238 Main, as before.
   239 
   240 * Logic image HOL-Main stops at theory Main, and thus facilitates
   241 experimentation due to shorter build times.
   242 
   243 * Logic image HOL-NSA contains theories of nonstandard analysis which
   244 were previously part of former HOL-Complex.  Entry point Hyperreal
   245 remains valid, but theories formerly using Complex_Main should now use
   246 new entry point Hypercomplex.
   247 
   248 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   249 Posix processes.  Avoids potentially expensive forking of the ML
   250 process.  New thread-based implementation also works on non-Unix
   251 platforms (Cygwin).  Provers are no longer hardwired, but defined
   252 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   253 commands are covered in the isar-ref manual.
   254 
   255 * Wrapper scripts for remote SystemOnTPTP service allows to use
   256 sledgehammer without local ATP installation (Vampire etc.). Other
   257 provers may be included via suitable ML wrappers, see also
   258 src/HOL/ATP_Linkup.thy.
   259 
   260 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   261 menu.
   262 
   263 * The metis method no longer fails because the theorem is too trivial
   264 (contains the empty clause).
   265 
   266 * The metis method now fails in the usual manner, rather than raising
   267 an exception, if it determines that it cannot prove the theorem.
   268 
   269 * Method "coherent" implements a prover for coherent logic (see also
   270 src/Tools/coherent.ML).
   271 
   272 * Constants "undefined" and "default" replace "arbitrary".  Usually
   273 "undefined" is the right choice to replace "arbitrary", though
   274 logically there is no difference.  INCOMPATIBILITY.
   275 
   276 * Command "value" now integrates different evaluation mechanisms.  The
   277 result of the first successful evaluation mechanism is printed.  In
   278 square brackets a particular named evaluation mechanisms may be
   279 specified (currently, [SML], [code] or [nbe]).  See further
   280 src/HOL/ex/Eval_Examples.thy.
   281 
   282 * Normalization by evaluation now allows non-leftlinear equations.
   283 Declare with attribute [code nbe].
   284 
   285 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   286 as the structured Isar versions "cases" and "induct", cf. the
   287 corresponding "cases" and "induct" attributes.  Mutual induction rules
   288 are now presented as a list of individual projections
   289 (e.g. foo_bar.inducts for types foo and bar); the old format with
   290 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   291 rare situations a different rule is selected --- notably nested tuple
   292 elimination instead of former prod.exhaust: use explicit (case_tac t
   293 rule: prod.exhaust) here.
   294 
   295 * Attributes "cases", "induct", "coinduct" support "del" option.
   296 
   297 * Removed fact "case_split_thm", which duplicates "case_split".
   298 
   299 * The option datatype has been moved to a new theory Option.  Renamed
   300 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   301 
   302 * New predicate "strict_mono" classifies strict functions on partial
   303 orders.  With strict functions on linear orders, reasoning about
   304 (in)equalities is facilitated by theorems "strict_mono_eq",
   305 "strict_mono_less_eq" and "strict_mono_less".
   306 
   307 * Some set operations are now proper qualified constants with
   308 authentic syntax.  INCOMPATIBILITY:
   309 
   310     op Int ~>   Set.Int
   311     op Un ~>    Set.Un
   312     INTER ~>    Set.INTER
   313     UNION ~>    Set.UNION
   314     Inter ~>    Set.Inter
   315     Union ~>    Set.Union
   316     {} ~>       Set.empty
   317     UNIV ~>     Set.UNIV
   318 
   319 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   320 theory Set.
   321 
   322 * Auxiliary class "itself" has disappeared -- classes without any
   323 parameter are treated as expected by the 'class' command.
   324 
   325 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   326 
   327 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   328 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   329 
   330 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   331 method "approximation".  It proves formulas on real values by using
   332 interval arithmetic.  In the formulas are also the transcendental
   333 functions sin, cos, tan, atan, ln, exp and the constant pi are
   334 allowed. For examples see
   335 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   336 
   337 * Theory "Reflection" now resides in HOL/Library.
   338 
   339 * Entry point to Word library now simply named "Word".
   340 INCOMPATIBILITY.
   341 
   342 * Made source layout more coherent with logical distribution
   343 structure:
   344 
   345     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   346     src/HOL/Library/Code_Message.thy ~> src/HOL/
   347     src/HOL/Library/GCD.thy ~> src/HOL/
   348     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   349     src/HOL/Library/Parity.thy ~> src/HOL/
   350     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   351     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   352     src/HOL/Real/Lubs.thy ~> src/HOL/
   353     src/HOL/Real/PReal.thy ~> src/HOL/
   354     src/HOL/Real/Rational.thy ~> src/HOL/
   355     src/HOL/Real/RComplete.thy ~> src/HOL/
   356     src/HOL/Real/RealDef.thy ~> src/HOL/
   357     src/HOL/Real/RealPow.thy ~> src/HOL/
   358     src/HOL/Real/Real.thy ~> src/HOL/
   359     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   360     src/HOL/Complex/Complex.thy ~> src/HOL/
   361     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   362     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   363     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   364     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   365     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   366     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   367     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   368     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   369     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   370     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   371     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   372     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   373     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   374     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   375     src/HOL/Real/Float ~> src/HOL/Library/
   376     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   377     src/HOL/Real/RealVector.thy ~> src/HOL/
   378 
   379     src/HOL/arith_data.ML ~> src/HOL/Tools
   380     src/HOL/hologic.ML ~> src/HOL/Tools
   381     src/HOL/simpdata.ML ~> src/HOL/Tools
   382     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   383     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   384     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   385     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   386     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   387     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   388     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   389 
   390     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   391     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   392     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   393     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   394     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   395     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   396 
   397 * If methods "eval" and "evaluation" encounter a structured proof
   398 state with !!/==>, only the conclusion is evaluated to True (if
   399 possible), avoiding strange error messages.
   400 
   401 * Method "sizechange" automates termination proofs using (a
   402 modification of) the size-change principle.  Requires SAT solver.  See
   403 src/HOL/ex/Termination.thy for examples.
   404 
   405 * Simplifier: simproc for let expressions now unfolds if bound
   406 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   407 
   408 * Method "arith": Linear arithmetic now ignores all inequalities when
   409 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   410 
   411 * New attribute "arith" for facts that should always be used
   412 automatically by arithmetic. It is intended to be used locally in
   413 proofs, e.g.
   414 
   415   assumes [arith]: "x > 0"
   416 
   417 Global usage is discouraged because of possible performance impact.
   418 
   419 * New classes "top" and "bot" with corresponding operations "top" and
   420 "bot" in theory Orderings; instantiation of class "complete_lattice"
   421 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   422 
   423 * Changed definition lemma "less_fun_def" in order to provide an
   424 instance for preorders on functions; use lemma "less_le" instead.
   425 INCOMPATIBILITY.
   426 
   427 * Theory Orderings: class "wellorder" moved here, with explicit
   428 induction rule "less_induct" as assumption.  For instantiation of
   429 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   430 INCOMPATIBILITY.
   431 
   432 * Theory Orderings: added class "preorder" as superclass of "order".
   433 INCOMPATIBILITY: Instantiation proofs for order, linorder
   434 etc. slightly changed.  Some theorems named order_class.* now named
   435 preorder_class.*.
   436 
   437 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   438 "diag" to "Id_on".
   439 
   440 * Theory Finite_Set: added a new fold combinator of type
   441 
   442   ('a => 'b => 'b) => 'b => 'a set => 'b
   443 
   444 Occasionally this is more convenient than the old fold combinator
   445 which is now defined in terms of the new one and renamed to
   446 fold_image.
   447 
   448 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   449 and "ring_simps" have been replaced by "algebra_simps" (which can be
   450 extended with further lemmas!).  At the moment both still exist but
   451 the former will disappear at some point.
   452 
   453 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   454 class recpower.  Type-specific simp rules for various recpower types
   455 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   456 
   457 rat_power_0    -> power_0
   458 rat_power_Suc  -> power_Suc
   459 realpow_0      -> power_0
   460 realpow_Suc    -> power_Suc
   461 complexpow_0   -> power_0
   462 complexpow_Suc -> power_Suc
   463 power_poly_0   -> power_0
   464 power_poly_Suc -> power_Suc
   465 
   466 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   467 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   468 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   469 of lemmas from Divides has been generalized from nat to class
   470 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   471 renames resulting from duplicate elimination:
   472 
   473     dvd_def_mod ~>          dvd_eq_mod_eq_0
   474     zero_dvd_iff ~>         dvd_0_left_iff
   475     dvd_0 ~>                dvd_0_right
   476     DIVISION_BY_ZERO_DIV ~> div_by_0
   477     DIVISION_BY_ZERO_MOD ~> mod_by_0
   478     mult_div ~>             div_mult_self2_is_id
   479     mult_mod ~>             mod_mult_self2_is_0
   480 
   481 * Theory IntDiv: removed many lemmas that are instances of class-based
   482 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   483 rename old lemmas as follows:
   484 
   485 dvd_diff               -> nat_dvd_diff
   486 dvd_zminus_iff         -> dvd_minus_iff
   487 mod_add1_eq            -> mod_add_eq
   488 mod_mult1_eq           -> mod_mult_right_eq
   489 mod_mult1_eq'          -> mod_mult_left_eq
   490 mod_mult_distrib_mod   -> mod_mult_eq
   491 nat_mod_add_left_eq    -> mod_add_left_eq
   492 nat_mod_add_right_eq   -> mod_add_right_eq
   493 nat_mod_div_trivial    -> mod_div_trivial
   494 nat_mod_mod_trivial    -> mod_mod_trivial
   495 zdiv_zadd_self1        -> div_add_self1
   496 zdiv_zadd_self2        -> div_add_self2
   497 zdiv_zmult_self1       -> div_mult_self2_is_id
   498 zdiv_zmult_self2       -> div_mult_self1_is_id
   499 zdvd_triv_left         -> dvd_triv_left
   500 zdvd_triv_right        -> dvd_triv_right
   501 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   502 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   503 zmod_zadd_left_eq      -> mod_add_left_eq
   504 zmod_zadd_right_eq     -> mod_add_right_eq
   505 zmod_zadd_self1        -> mod_add_self1
   506 zmod_zadd_self2        -> mod_add_self2
   507 zmod_zadd1_eq          -> mod_add_eq
   508 zmod_zdiff1_eq         -> mod_diff_eq
   509 zmod_zdvd_zmod         -> mod_mod_cancel
   510 zmod_zmod_cancel       -> mod_mod_cancel
   511 zmod_zmult_self1       -> mod_mult_self2_is_0
   512 zmod_zmult_self2       -> mod_mult_self1_is_0
   513 zmod_1                 -> mod_by_1
   514 zdiv_1                 -> div_by_1
   515 zdvd_abs1              -> abs_dvd_iff
   516 zdvd_abs2              -> dvd_abs_iff
   517 zdvd_refl              -> dvd_refl
   518 zdvd_trans             -> dvd_trans
   519 zdvd_zadd              -> dvd_add
   520 zdvd_zdiff             -> dvd_diff
   521 zdvd_zminus_iff        -> dvd_minus_iff
   522 zdvd_zminus2_iff       -> minus_dvd_iff
   523 zdvd_zmultD            -> dvd_mult_right
   524 zdvd_zmultD2           -> dvd_mult_left
   525 zdvd_zmult_mono        -> mult_dvd_mono
   526 zdvd_0_right           -> dvd_0_right
   527 zdvd_0_left            -> dvd_0_left_iff
   528 zdvd_1_left            -> one_dvd
   529 zminus_dvd_iff         -> minus_dvd_iff
   530 
   531 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   532 
   533 * The real numbers offer decimal input syntax: 12.34 is translated
   534 into 1234/10^2. This translation is not reversed upon output.
   535 
   536 * Theory Library/Polynomial defines an abstract type 'a poly of
   537 univariate polynomials with coefficients of type 'a.  In addition to
   538 the standard ring operations, it also supports div and mod.  Code
   539 generation is also supported, using list-style constructors.
   540 
   541 * Theory Library/Inner_Product defines a class of real_inner for real
   542 inner product spaces, with an overloaded operation inner :: 'a => 'a
   543 => real.  Class real_inner is a subclass of real_normed_vector from
   544 theory RealVector.
   545 
   546 * Theory Library/Product_Vector provides instances for the product
   547 type 'a * 'b of several classes from RealVector and Inner_Product.
   548 Definitions of addition, subtraction, scalar multiplication, norms,
   549 and inner products are included.
   550 
   551 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   552 addition to the field operations, numerals and case syntax are also
   553 supported.
   554 
   555 * Theory Library/Diagonalize provides constructive version of Cantor's
   556 first diagonalization argument.
   557 
   558 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   559 zlcm (for int); carried together from various gcd/lcm developements in
   560 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   561 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   562 may recover tupled syntax as follows:
   563 
   564     hide (open) const gcd
   565     abbreviation gcd where
   566       "gcd == (%(a, b). GCD.gcd a b)"
   567     notation (output)
   568       GCD.gcd ("gcd '(_, _')")
   569 
   570 The same works for lcm, zgcd, zlcm.
   571 
   572 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   573 instantiations for algebraic structures.  Removed some duplicate
   574 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   575 
   576 * ML antiquotation @{code} takes a constant as argument and generates
   577 corresponding code in background and inserts name of the corresponding
   578 resulting ML value/function/datatype constructor binding in place.
   579 All occurrences of @{code} with a single ML block are generated
   580 simultaneously.  Provides a generic and safe interface for
   581 instrumentalizing code generation.  See
   582 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   583 In future you ought to refrain from ad-hoc compiling generated SML
   584 code on the ML toplevel.  Note that (for technical reasons) @{code}
   585 cannot refer to constants for which user-defined serializations are
   586 set.  Refer to the corresponding ML counterpart directly in that
   587 cases.
   588 
   589 * Command 'rep_datatype': instead of theorem names the command now
   590 takes a list of terms denoting the constructors of the type to be
   591 represented as datatype.  The characteristic theorems have to be
   592 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   593 have disappeared in favour of existing ones:
   594 
   595     unit_induct                 ~> unit.induct
   596     prod_induct                 ~> prod.induct
   597     sum_induct                  ~> sum.induct
   598     Suc_Suc_eq                  ~> nat.inject
   599     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   600 
   601 
   602 *** HOL-Algebra ***
   603 
   604 * New locales for orders and lattices where the equivalence relation
   605 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   606 locales use a record structure with field eq for the equivalence.
   607 
   608 * New theory of factorial domains.
   609 
   610 * Units_l_inv and Units_r_inv are now simp rules by default.
   611 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   612 and/or r_inv will now also require deletion of these lemmas.
   613 
   614 * Renamed the following theorems, INCOMPATIBILITY:
   615 
   616 UpperD ~> Upper_memD
   617 LowerD ~> Lower_memD
   618 least_carrier ~> least_closed
   619 greatest_carrier ~> greatest_closed
   620 greatest_Lower_above ~> greatest_Lower_below
   621 one_zero ~> carrier_one_zero
   622 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   623 
   624 
   625 *** HOL-Nominal ***
   626 
   627 * Nominal datatypes can now contain type-variables.
   628 
   629 * Commands 'nominal_inductive' and 'equivariance' work with local
   630 theory targets.
   631 
   632 * Nominal primrec can now works with local theory targets and its
   633 specification syntax now conforms to the general format as seen in
   634 'inductive' etc.
   635 
   636 * Method "perm_simp" honours the standard simplifier attributes
   637 (no_asm), (no_asm_use) etc.
   638 
   639 * The new predicate #* is defined like freshness, except that on the
   640 left hand side can be a set or list of atoms.
   641 
   642 * Experimental command 'nominal_inductive2' derives strong induction
   643 principles for inductive definitions.  In contrast to
   644 'nominal_inductive', which can only deal with a fixed number of
   645 binders, it can deal with arbitrary expressions standing for sets of
   646 atoms to be avoided.  The only inductive definition we have at the
   647 moment that needs this generalisation is the typing rule for Lets in
   648 the algorithm W:
   649 
   650  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   651  -----------------------------------------------------------------
   652          Gamma |- Let x be t1 in t2 : T2
   653 
   654 In this rule one wants to avoid all the binders that are introduced by
   655 "close Gamma T1".  We are looking for other examples where this
   656 feature might be useful.  Please let us know.
   657 
   658 
   659 *** HOLCF ***
   660 
   661 * Reimplemented the simplification procedure for proving continuity
   662 subgoals.  The new simproc is extensible; users can declare additional
   663 continuity introduction rules with the attribute [cont2cont].
   664 
   665 * The continuity simproc now uses a different introduction rule for
   666 solving continuity subgoals on terms with lambda abstractions.  In
   667 some rare cases the new simproc may fail to solve subgoals that the
   668 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   669 Potential INCOMPATIBILITY.
   670 
   671 * Command 'fixrec': specification syntax now conforms to the general
   672 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   673 examples.  INCOMPATIBILITY.
   674 
   675 
   676 *** ZF ***
   677 
   678 * Proof of Zorn's Lemma for partial orders.
   679 
   680 
   681 *** ML ***
   682 
   683 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   684 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   685 depends on multithreading, so timouts will not work before Poly/ML
   686 5.2.1!
   687 
   688 * High-level support for concurrent ML programming, see
   689 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   690 particularly convenient to organize independent functional
   691 computations.  The concept of "synchronized variables" provides a
   692 higher-order interface for components with shared state, avoiding the
   693 delicate details of mutexes and condition variables.  (Requires
   694 Poly/ML 5.2.1 or later.)
   695 
   696 * ML bindings produced via Isar commands are stored within the Isar
   697 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   698 become thread-safe and work with undo as expected (concerning
   699 top-level bindings, not side-effects on global references).
   700 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   701 compiler at runtime; really global bindings need to be given outside a
   702 theory.  (Requires Poly/ML 5.2 or later.)
   703 
   704 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   705 context.  Top-level ML bindings are stored within the proof context in
   706 a purely sequential fashion, disregarding the nested proof structure.
   707 ML bindings introduced by 'ML_prf' are discarded at the end of the
   708 proof.  (Requires Poly/ML 5.2 or later.)
   709 
   710 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   711 and Method.setup, as well as Isar commands 'attribute_setup' and
   712 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   713 existing code accordingly, or use plain 'setup' together with old
   714 Method.add_method.
   715 
   716 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   717 to 'a -> thm, while results are always tagged with an authentic oracle
   718 name.  The Isar command 'oracle' is now polymorphic, no argument type
   719 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   720 accordingly.  Note that extra performance may be gained by producing
   721 the cterm carefully, avoiding slow Thm.cterm_of.
   722 
   723 * Simplified interface for defining document antiquotations via
   724 ThyOutput.antiquotation, ThyOutput.output, and optionally
   725 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   726 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   727 examples.
   728 
   729 * More systematic treatment of long names, abstract name bindings, and
   730 name space operations.  Basic operations on qualified names have been
   731 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   732 Long_Name.append.  Old type bstring has been mostly replaced by
   733 abstract type binding (see structure Binding), which supports precise
   734 qualification by packages and local theory targets, as well as proper
   735 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   736 bstring values into Binding.name, or better pass through abstract
   737 bindings everywhere.  See further src/Pure/General/long_name.ML,
   738 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   739 
   740 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   741 LocalTheory.note etc.) now refer to the *full* internal name, not the
   742 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   743 
   744 * Disposed old type and term read functions (Sign.read_def_typ,
   745 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   746 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   747 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   748 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   749 resort for legacy applications.
   750 
   751 * Disposed old declarations, tactics, tactic combinators that refer to
   752 the simpset or claset of an implicit theory (such as Addsimps,
   753 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   754 embedded ML text, or local_simpset_of with a proper context passed as
   755 explicit runtime argument.
   756 
   757 * Rules and tactics that read instantiations (read_instantiate,
   758 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   759 context, which is required for parsing and type-checking.  Moreover,
   760 the variables are specified as plain indexnames, not string encodings
   761 thereof.  INCOMPATIBILITY.
   762 
   763 * Generic Toplevel.add_hook interface allows to analyze the result of
   764 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   765 for theorem dependency output of transactions resulting in a new
   766 theory state.
   767 
   768 * ML antiquotations: block-structured compilation context indicated by
   769 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   770 
   771   @{binding name}                         - basic name binding
   772   @{let ?pat = term}                      - term abbreviation (HO matching)
   773   @{note name = fact}                     - fact abbreviation
   774   @{thm fact}                             - singleton fact (with attributes)
   775   @{thms fact}                            - general fact (with attributes)
   776   @{lemma prop by method}                 - singleton goal
   777   @{lemma prop by meth1 meth2}            - singleton goal
   778   @{lemma prop1 ... propN by method}      - general goal
   779   @{lemma prop1 ... propN by meth1 meth2} - general goal
   780   @{lemma (open) ...}                     - open derivation
   781 
   782 
   783 *** System ***
   784 
   785 * The Isabelle "emacs" tool provides a specific interface to invoke
   786 Proof General / Emacs, with more explicit failure if that is not
   787 installed (the old isabelle-interface script silently falls back on
   788 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   789 installation location of the Proof General distribution.
   790 
   791 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   792 the Isabelle process into a JVM/Scala application.  See
   793 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   794 process wrapper has been discontinued.)
   795 
   796 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   797 
   798 * Various status messages (with exact source position information) are
   799 emitted, if proper markup print mode is enabled.  This allows
   800 user-interface components to provide detailed feedback on internal
   801 prover operations.
   802 
   803 
   804 
   805 New in Isabelle2008 (June 2008)
   806 -------------------------------
   807 
   808 *** General ***
   809 
   810 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   811 and updated, with formally checked references as hyperlinks.
   812 
   813 * Theory loader: use_thy (and similar operations) no longer set the
   814 implicit ML context, which was occasionally hard to predict and in
   815 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   816 provides a proper context already.
   817 
   818 * Theory loader: old-style ML proof scripts being *attached* to a thy
   819 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   820 'use' within a theory file will do the job.
   821 
   822 * Name space merge now observes canonical order, i.e. the second space
   823 is inserted into the first one, while existing entries in the first
   824 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   825 swap theory imports.
   826 
   827 * Syntax: symbol \<chi> is now considered a letter.  Potential
   828 INCOMPATIBILITY in identifier syntax etc.
   829 
   830 * Outer syntax: string tokens no longer admit escaped white space,
   831 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   832 white space without escapes.
   833 
   834 * Outer syntax: string tokens may contain arbitrary character codes
   835 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   836 "foo_bar".
   837 
   838 
   839 *** Pure ***
   840 
   841 * Context-dependent token translations.  Default setup reverts locally
   842 fixed variables, and adds hilite markup for undeclared frees.
   843 
   844 * Unused theorems can be found using the new command 'unused_thms'.
   845 There are three ways of invoking it:
   846 
   847 (1) unused_thms
   848      Only finds unused theorems in the current theory.
   849 
   850 (2) unused_thms thy_1 ... thy_n -
   851      Finds unused theorems in the current theory and all of its ancestors,
   852      excluding the theories thy_1 ... thy_n and all of their ancestors.
   853 
   854 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   855      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   856      their ancestors, excluding the theories thy_1 ... thy_n and all of
   857      their ancestors.
   858 
   859 In order to increase the readability of the list produced by
   860 unused_thms, theorems that have been created by a particular instance
   861 of a theory command such as 'inductive' or 'function' are considered
   862 to belong to the same "group", meaning that if at least one theorem in
   863 this group is used, the other theorems in the same group are no longer
   864 reported as unused.  Moreover, if all theorems in the group are
   865 unused, only one theorem in the group is displayed.
   866 
   867 Note that proof objects have to be switched on in order for
   868 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   869 usually the case when using Proof General with the default settings).
   870 
   871 * Authentic naming of facts disallows ad-hoc overwriting of previous
   872 theorems within the same name space.  INCOMPATIBILITY, need to remove
   873 duplicate fact bindings, or even accidental fact duplications.  Note
   874 that tools may maintain dynamically scoped facts systematically, using
   875 PureThy.add_thms_dynamic.
   876 
   877 * Command 'hide' now allows to hide from "fact" name space as well.
   878 
   879 * Eliminated destructive theorem database, simpset, claset, and
   880 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   881 update of theories within ML code.
   882 
   883 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   884 INCOMPATIBILITY, object-logics depending on former Pure require
   885 additional setup PureThy.old_appl_syntax_setup; object-logics
   886 depending on former CPure need to refer to Pure.
   887 
   888 * Commands 'use' and 'ML' are now purely functional, operating on
   889 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   890 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   891 INCOMPATIBILITY.
   892 
   893 * Command 'setup': discontinued implicit version with ML reference.
   894 
   895 * Instantiation target allows for simultaneous specification of class
   896 instance operations together with an instantiation proof.
   897 Type-checking phase allows to refer to class operations uniformly.
   898 See src/HOL/Complex/Complex.thy for an Isar example and
   899 src/HOL/Library/Eval.thy for an ML example.
   900 
   901 * Indexing of literal facts: be more serious about including only
   902 facts from the visible specification/proof context, but not the
   903 background context (locale etc.).  Affects `prop` notation and method
   904 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   905 situations.
   906 
   907 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   908 "(open)" option, which used to expose internal bound variables to the
   909 proof text.
   910 
   911 * Isar statements: removed obsolete case "rule_context".
   912 INCOMPATIBILITY, better use explicit fixes/assumes.
   913 
   914 * Locale proofs: default proof step now includes 'unfold_locales';
   915 hence 'proof' without argument may be used to unfold locale
   916 predicates.
   917 
   918 
   919 *** Document preparation ***
   920 
   921 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   922 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   923 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   924 spot); renamed link color from "darkblue" to "linkcolor" (default
   925 value unchanged, can be redefined via \definecolor); no longer sets
   926 "a4paper" option (unnecessary or even intrusive).
   927 
   928 * Antiquotation @{lemma A method} proves proposition A by the given
   929 method (either a method name or a method name plus (optional) method
   930 arguments in parentheses) and prints A just like @{prop A}.
   931 
   932 
   933 *** HOL ***
   934 
   935 * New primrec package.  Specification syntax conforms in style to
   936 definition/function/....  No separate induction rule is provided.  The
   937 "primrec" command distinguishes old-style and new-style specifications
   938 by syntax.  The former primrec package is now named OldPrimrecPackage.
   939 When adjusting theories, beware: constants stemming from new-style
   940 primrec specifications have authentic syntax.
   941 
   942 * Metis prover is now an order of magnitude faster, and also works
   943 with multithreading.
   944 
   945 * Metis: the maximum number of clauses that can be produced from a
   946 theorem is now given by the attribute max_clauses.  Theorems that
   947 exceed this number are ignored, with a warning printed.
   948 
   949 * Sledgehammer no longer produces structured proofs by default. To
   950 enable, declare [[sledgehammer_full = true]].  Attributes
   951 reconstruction_modulus, reconstruction_sorts renamed
   952 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   953 
   954 * Method "induct_scheme" derives user-specified induction rules
   955 from well-founded induction and completeness of patterns. This factors
   956 out some operations that are done internally by the function package
   957 and makes them available separately.  See
   958 src/HOL/ex/Induction_Scheme.thy for examples.
   959 
   960 * More flexible generation of measure functions for termination
   961 proofs: Measure functions can be declared by proving a rule of the
   962 form "is_measure f" and giving it the [measure_function] attribute.
   963 The "is_measure" predicate is logically meaningless (always true), and
   964 just guides the heuristic.  To find suitable measure functions, the
   965 termination prover sets up the goal "is_measure ?f" of the appropriate
   966 type and generates all solutions by prolog-style backwards proof using
   967 the declared rules.
   968 
   969 This setup also deals with rules like 
   970 
   971   "is_measure f ==> is_measure (list_size f)"
   972 
   973 which accommodates nested datatypes that recurse through lists.
   974 Similar rules are predeclared for products and option types.
   975 
   976 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   977 
   978   INCOMPATIBILITIES:
   979 
   980   - Definitions of overloaded constants on sets have to be replaced by
   981     definitions on => and bool.
   982 
   983   - Some definitions of overloaded operators on sets can now be proved
   984     using the definitions of the operators on => and bool.  Therefore,
   985     the following theorems have been renamed:
   986 
   987       subset_def   -> subset_eq
   988       psubset_def  -> psubset_eq
   989       set_diff_def -> set_diff_eq
   990       Compl_def    -> Compl_eq
   991       Sup_set_def  -> Sup_set_eq
   992       Inf_set_def  -> Inf_set_eq
   993       sup_set_def  -> sup_set_eq
   994       inf_set_def  -> inf_set_eq
   995 
   996   - Due to the incompleteness of the HO unification algorithm, some
   997     rules such as subst may require manual instantiation, if some of
   998     the unknowns in the rule is a set.
   999 
  1000   - Higher order unification and forward proofs:
  1001     The proof pattern
  1002 
  1003       have "P (S::'a set)" <...>
  1004       then have "EX S. P S" ..
  1005 
  1006     no longer works (due to the incompleteness of the HO unification
  1007     algorithm) and must be replaced by the pattern
  1008 
  1009       have "EX S. P S"
  1010       proof
  1011         show "P S" <...>
  1012       qed
  1013 
  1014   - Calculational reasoning with subst (or similar rules):
  1015     The proof pattern
  1016 
  1017       have "P (S::'a set)" <...>
  1018       also have "S = T" <...>
  1019       finally have "P T" .
  1020 
  1021     no longer works (for similar reasons as the previous example) and
  1022     must be replaced by something like
  1023 
  1024       have "P (S::'a set)" <...>
  1025       moreover have "S = T" <...>
  1026       ultimately have "P T" by simp
  1027 
  1028   - Tactics or packages written in ML code:
  1029     Code performing pattern matching on types via
  1030 
  1031       Type ("set", [T]) => ...
  1032 
  1033     must be rewritten. Moreover, functions like strip_type or
  1034     binder_types no longer return the right value when applied to a
  1035     type of the form
  1036 
  1037       T1 => ... => Tn => U => bool
  1038 
  1039     rather than
  1040 
  1041       T1 => ... => Tn => U set
  1042 
  1043 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1044 Wellfounded_Relations to theory Wellfounded.
  1045 
  1046 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1047 
  1048 * Class finite no longer treats UNIV as class parameter.  Use class
  1049 enum from theory Library/Enum instead to achieve a similar effect.
  1050 INCOMPATIBILITY.
  1051 
  1052 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1053 and "Cons".  INCOMPATIBILITY.
  1054 
  1055 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1056 Potential INCOMPATIBILITY.
  1057 
  1058 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1059 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1060 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1061 
  1062 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1063 the same name in theory Orderings:
  1064 
  1065   less_trans
  1066   less_linear
  1067   le_imp_less_or_eq
  1068   le_less_trans
  1069   less_le_trans
  1070   less_not_sym
  1071   less_asym
  1072 
  1073 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1074 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1075 and different variable names.
  1076 
  1077 * Library/Option_ord.thy: Canonical order on option type.
  1078 
  1079 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1080 finite maps.
  1081 
  1082 * Library/Countable.thy: Type class for countable types.
  1083 
  1084 * Theory Int: The representation of numerals has changed.  The infix
  1085 operator BIT and the bit datatype with constructors B0 and B1 have
  1086 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1087 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1088 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1089 accordingly.
  1090 
  1091 * Theory Nat: definition of <= and < on natural numbers no longer
  1092 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1093 le_def and less_def have disappeared.  Consider lemmas not_less
  1094 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1095 
  1096 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1097 (whose purpose mainly is for various fold_set functionals) have been
  1098 abandoned in favor of the existing algebraic classes
  1099 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1100 lower_semilattice (resp. upper_semilattice) and linorder.
  1101 INCOMPATIBILITY.
  1102 
  1103 * Theory Transitive_Closure: induct and cases rules now declare proper
  1104 case_names ("base" and "step").  INCOMPATIBILITY.
  1105 
  1106 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1107 lattices.  The form set-specific version is available as
  1108 Inductive.lfp_ordinal_induct_set.
  1109 
  1110 * Renamed theorems "power.simps" to "power_int.simps".
  1111 INCOMPATIBILITY.
  1112 
  1113 * Class semiring_div provides basic abstract properties of semirings
  1114 with division and modulo operations.  Subsumes former class dvd_mod.
  1115 
  1116 * Merged theories IntDef, Numeral and IntArith into unified theory
  1117 Int.  INCOMPATIBILITY.
  1118 
  1119 * Theory Library/Code_Index: type "index" now represents natural
  1120 numbers rather than integers.  INCOMPATIBILITY.
  1121 
  1122 * New class "uminus" with operation "uminus" (split of from class
  1123 "minus" which now only has operation "minus", binary).
  1124 INCOMPATIBILITY.
  1125 
  1126 * Constants "card", "internal_split", "option_map" now with authentic
  1127 syntax.  INCOMPATIBILITY.
  1128 
  1129 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1130 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1131 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1132 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1133 Sup_set_def, le_def, less_def, option_map_def now with object
  1134 equality.  INCOMPATIBILITY.
  1135 
  1136 * Records. Removed K_record, and replaced it by pure lambda term
  1137 %x. c. The simplifier setup is now more robust against eta expansion.
  1138 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1139 
  1140 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1141 
  1142 * Library/ListVector: new theory of arithmetic vector operations.
  1143 
  1144 * Library/Order_Relation: new theory of various orderings as sets of
  1145 pairs.  Defines preorders, partial orders, linear orders and
  1146 well-orders on sets and on types.
  1147 
  1148 
  1149 *** ZF ***
  1150 
  1151 * Renamed some theories to allow to loading both ZF and HOL in the
  1152 same session:
  1153 
  1154   Datatype  -> Datatype_ZF
  1155   Inductive -> Inductive_ZF
  1156   Int       -> Int_ZF
  1157   IntDiv    -> IntDiv_ZF
  1158   Nat       -> Nat_ZF
  1159   List      -> List_ZF
  1160   Main      -> Main_ZF
  1161 
  1162 INCOMPATIBILITY: ZF theories that import individual theories below
  1163 Main might need to be adapted.  Regular theory Main is still
  1164 available, as trivial extension of Main_ZF.
  1165 
  1166 
  1167 *** ML ***
  1168 
  1169 * ML within Isar: antiquotation @{const name} or @{const
  1170 name(typargs)} produces statically-checked Const term.
  1171 
  1172 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1173 (of the same name).  Removed obsolete print command.
  1174 
  1175 * Removed obsolete "use_legacy_bindings" function.
  1176 
  1177 * The ``print mode'' is now a thread-local value derived from a global
  1178 template (the former print_mode reference), thus access becomes
  1179 non-critical.  The global print_mode reference is for session
  1180 management only; user-code should use print_mode_value,
  1181 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1182 
  1183 * Functions system/system_out provide a robust way to invoke external
  1184 shell commands, with propagation of interrupts (requires Poly/ML
  1185 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1186 
  1187 
  1188 *** System ***
  1189 
  1190 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1191 in accordance with Proof General 3.7, which prefers GNU emacs.
  1192 
  1193 * isatool tty runs Isabelle process with plain tty interaction;
  1194 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1195 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1196 
  1197 * isatool browser now works with Cygwin as well, using general
  1198 "javapath" function defined in Isabelle process environment.
  1199 
  1200 * YXML notation provides a simple and efficient alternative to
  1201 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1202 isatool yxml as described in the Isabelle system manual.
  1203 
  1204 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1205 provides general wrapper for managing an Isabelle process in a robust
  1206 fashion, with ``cooked'' output from stdin/stderr.
  1207 
  1208 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1209 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1210 
  1211 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1212 way of changing the user's settings is via
  1213 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1214 script.
  1215 
  1216 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1217 cores of the underlying machine, which is a good starting point for
  1218 optimal performance tuning.  The corresponding usedir option -M allows
  1219 "max" as an alias for "0".  WARNING: does not work on certain versions
  1220 of Mac OS (with Poly/ML 5.1).
  1221 
  1222 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1223 adverse effect of Isabelle flooding interactive front-ends (notably
  1224 ProofGeneral / XEmacs).
  1225 
  1226 
  1227 
  1228 New in Isabelle2007 (November 2007)
  1229 -----------------------------------
  1230 
  1231 *** General ***
  1232 
  1233 * More uniform information about legacy features, notably a
  1234 warning/error of "Legacy feature: ...", depending on the state of the
  1235 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1236 legacy features will disappear eventually.
  1237 
  1238 * Theory syntax: the header format ``theory A = B + C:'' has been
  1239 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1240 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1241 
  1242 * Theory syntax: the old non-Isar theory file format has been
  1243 discontinued altogether.  Note that ML proof scripts may still be used
  1244 with Isar theories; migration is usually quite simple with the ML
  1245 function use_legacy_bindings.  INCOMPATIBILITY.
  1246 
  1247 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1248 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1249 quotes.
  1250 
  1251 * Theory loader: be more serious about observing the static theory
  1252 header specifications (including optional directories), but not the
  1253 accidental file locations of previously successful loads.  The strict
  1254 update policy of former update_thy is now already performed by
  1255 use_thy, so the former has been removed; use_thys updates several
  1256 theories simultaneously, just as 'imports' within a theory header
  1257 specification, but without merging the results.  Potential
  1258 INCOMPATIBILITY: may need to refine theory headers and commands
  1259 ROOT.ML which depend on load order.
  1260 
  1261 * Theory loader: optional support for content-based file
  1262 identification, instead of the traditional scheme of full physical
  1263 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1264 (cf. the system manual).  The new scheme allows to work with
  1265 non-finished theories in persistent session images, such that source
  1266 files may be moved later on without requiring reloads.
  1267 
  1268 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1269 file (with the same base name as the theory) are considered a legacy
  1270 feature, which will disappear eventually. Even now, the theory loader
  1271 no longer maintains dependencies on such files.
  1272 
  1273 * Syntax: the scope for resolving ambiguities via type-inference is
  1274 now limited to individual terms, instead of whole simultaneous
  1275 specifications as before. This greatly reduces the complexity of the
  1276 syntax module and improves flexibility by separating parsing and
  1277 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1278 'fixes' etc.) are required in rare situations.
  1279 
  1280 * Syntax: constants introduced by new-style packages ('definition',
  1281 'abbreviation' etc.) are passed through the syntax module in
  1282 ``authentic mode''. This means that associated mixfix annotations
  1283 really stick to such constants, independently of potential name space
  1284 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1285 trees are represented slightly differently, may need to adapt syntax
  1286 translations accordingly. Use CONST marker in 'translations' and
  1287 @{const_syntax} antiquotation in 'parse_translation' etc.
  1288 
  1289 * Legacy goal package: reduced interface to the bare minimum required
  1290 to keep existing proof scripts running.  Most other user-level
  1291 functions are now part of the OldGoals structure, which is *not* open
  1292 by default (consider isatool expandshort before open OldGoals).
  1293 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1294 these tend to cause confusion about the actual goal (!) context being
  1295 used here, which is not necessarily the same as the_context().
  1296 
  1297 * Command 'find_theorems': supports "*" wild-card in "name:"
  1298 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1299 support a specific search form (see ProofGeneral/CHANGES).
  1300 
  1301 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1302 by default, which means that "prems" (and also "fixed variables") are
  1303 suppressed from proof state output.  Note that the ProofGeneral
  1304 settings mechanism allows to change and save options persistently, but
  1305 older versions of Isabelle will fail to start up if a negative prems
  1306 limit is imposed.
  1307 
  1308 * Local theory targets may be specified by non-nested blocks of
  1309 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1310 contain definitions, theorems etc., including any derived mechanism
  1311 that has been implemented on top of these primitives.  This concept
  1312 generalizes the existing ``theorem (in ...)'' towards more versatility
  1313 and scalability.
  1314 
  1315 * Proof General interface: proper undo of final 'end' command;
  1316 discontinued Isabelle/classic mode (ML proof scripts).
  1317 
  1318 
  1319 *** Document preparation ***
  1320 
  1321 * Added antiquotation @{theory name} which prints the given name,
  1322 after checking that it refers to a valid ancestor theory in the
  1323 current context.
  1324 
  1325 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1326 check the given source text as ML type/structure, printing verbatim.
  1327 
  1328 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1329 "c args == rhs" given in the current context.  (Any number of
  1330 arguments may be given on the LHS.)
  1331 
  1332 
  1333 *** Pure ***
  1334 
  1335 * The 'class' package offers a combination of axclass and locale to
  1336 achieve Haskell-like type classes in Isabelle.  Definitions and
  1337 theorems within a class context produce both relative results (with
  1338 implicit parameters according to the locale context), and polymorphic
  1339 constants with qualified polymorphism (according to the class
  1340 context).  Within the body context of a 'class' target, a separate
  1341 syntax layer ("user space type system") takes care of converting
  1342 between global polymorphic consts and internal locale representation.
  1343 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1344 "isatool doc classes" provides a tutorial.
  1345 
  1346 * Generic code generator framework allows to generate executable
  1347 code for ML and Haskell (including Isabelle classes).  A short usage
  1348 sketch:
  1349 
  1350     internal compilation:
  1351         export_code <list of constants (term syntax)> in SML
  1352     writing SML code to a file:
  1353         export_code <list of constants (term syntax)> in SML <filename>
  1354     writing OCaml code to a file:
  1355         export_code <list of constants (term syntax)> in OCaml <filename>
  1356     writing Haskell code to a bunch of files:
  1357         export_code <list of constants (term syntax)> in Haskell <filename>
  1358 
  1359     evaluating closed propositions to True/False using code generation:
  1360         method ``eval''
  1361 
  1362 Reasonable default setup of framework in HOL.
  1363 
  1364 Theorem attributs for selecting and transforming function equations theorems:
  1365 
  1366     [code fun]:        select a theorem as function equation for a specific constant
  1367     [code fun del]:    deselect a theorem as function equation for a specific constant
  1368     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1369     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1370 
  1371 User-defined serializations (target in {SML, OCaml, Haskell}):
  1372 
  1373     code_const <and-list of constants (term syntax)>
  1374       {(target) <and-list of const target syntax>}+
  1375 
  1376     code_type <and-list of type constructors>
  1377       {(target) <and-list of type target syntax>}+
  1378 
  1379     code_instance <and-list of instances>
  1380       {(target)}+
  1381         where instance ::= <type constructor> :: <class>
  1382 
  1383     code_class <and_list of classes>
  1384       {(target) <and-list of class target syntax>}+
  1385         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1386 
  1387 code_instance and code_class only are effective to target Haskell.
  1388 
  1389 For example usage see src/HOL/ex/Codegenerator.thy and
  1390 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1391 generation from Isabelle/HOL theories is available via "isatool doc
  1392 codegen".
  1393 
  1394 * Code generator: consts in 'consts_code' Isar commands are now
  1395 referred to by usual term syntax (including optional type
  1396 annotations).
  1397 
  1398 * Command 'no_translations' removes translation rules from theory
  1399 syntax.
  1400 
  1401 * Overloaded definitions are now actually checked for acyclic
  1402 dependencies.  The overloading scheme is slightly more general than
  1403 that of Haskell98, although Isabelle does not demand an exact
  1404 correspondence to type class and instance declarations.
  1405 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1406 exotic versions of overloading -- at the discretion of the user!
  1407 
  1408 Polymorphic constants are represented via type arguments, i.e. the
  1409 instantiation that matches an instance against the most general
  1410 declaration given in the signature.  For example, with the declaration
  1411 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1412 as c(nat).  Overloading is essentially simultaneous structural
  1413 recursion over such type arguments.  Incomplete specification patterns
  1414 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1415 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1416 Command 'print_theory' outputs the normalized system of recursive
  1417 equations, see section "definitions".
  1418 
  1419 * Configuration options are maintained within the theory or proof
  1420 context (with name and type bool/int/string), providing a very simple
  1421 interface to a poor-man's version of general context data.  Tools may
  1422 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1423 these values using Config.get etc.  Users may change options via an
  1424 associated attribute of the same name.  This form of context
  1425 declaration works particularly well with commands 'declare' or
  1426 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1427 very easy to avoid global references, which would not observe Isar
  1428 toplevel undo/redo and fail to work with multithreading.
  1429 
  1430 Various global ML references of Pure and HOL have been turned into
  1431 configuration options:
  1432 
  1433   Unify.search_bound		unify_search_bound
  1434   Unify.trace_bound		unify_trace_bound
  1435   Unify.trace_simp		unify_trace_simp
  1436   Unify.trace_types		unify_trace_types
  1437   Simplifier.simp_depth_limit	simp_depth_limit
  1438   Blast.depth_limit		blast_depth_limit
  1439   DatatypeProp.dtK		datatype_distinctness_limit
  1440   fast_arith_neq_limit  	fast_arith_neq_limit
  1441   fast_arith_split_limit	fast_arith_split_limit
  1442 
  1443 * Named collections of theorems may be easily installed as context
  1444 data using the functor NamedThmsFun (see also
  1445 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1446 attributes; there is also a toplevel print command.  This facility is
  1447 just a common case of general context data, which is the preferred way
  1448 for anything more complex than just a list of facts in canonical
  1449 order.
  1450 
  1451 * Isar: command 'declaration' augments a local theory by generic
  1452 declaration functions written in ML.  This enables arbitrary content
  1453 being added to the context, depending on a morphism that tells the
  1454 difference of the original declaration context wrt. the application
  1455 context encountered later on.
  1456 
  1457 * Isar: proper interfaces for simplification procedures.  Command
  1458 'simproc_setup' declares named simprocs (with match patterns, and body
  1459 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1460 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1461 
  1462 * Isar: an extra pair of brackets around attribute declarations
  1463 abbreviates a theorem reference involving an internal dummy fact,
  1464 which will be ignored later --- only the effect of the attribute on
  1465 the background context will persist.  This form of in-place
  1466 declarations is particularly useful with commands like 'declare' and
  1467 'using', for example ``have A using [[simproc a]] by simp''.
  1468 
  1469 * Isar: method "assumption" (and implicit closing of subproofs) now
  1470 takes simple non-atomic goal assumptions into account: after applying
  1471 an assumption as a rule the resulting subgoals are solved by atomic
  1472 assumption steps.  This is particularly useful to finish 'obtain'
  1473 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1474 without referring to the original premise "!!x. P x ==> thesis" in the
  1475 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1476 more permissive.
  1477 
  1478 * Isar: implicit use of prems from the Isar proof context is
  1479 considered a legacy feature.  Common applications like ``have A .''
  1480 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1481 referencing facts explicitly here improves readability and
  1482 maintainability of proof texts.
  1483 
  1484 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1485 the obtained context from the course of reasoning!  For example:
  1486 
  1487   assume "EX x y. A x & B y"   -- "any previous fact"
  1488   then guess x and y by clarify
  1489 
  1490 This technique is potentially adventurous, depending on the facts and
  1491 proof tools being involved here.
  1492 
  1493 * Isar: known facts from the proof context may be specified as literal
  1494 propositions, using ASCII back-quote syntax.  This works wherever
  1495 named facts used to be allowed so far, in proof commands, proof
  1496 methods, attributes etc.  Literal facts are retrieved from the context
  1497 according to unification of type and term parameters.  For example,
  1498 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1499 theorems in the current context, then these are valid literal facts:
  1500 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1501 
  1502 There is also a proof method "fact" which does the same composition
  1503 for explicit goal states, e.g. the following proof texts coincide with
  1504 certain special cases of literal facts:
  1505 
  1506   have "A" by fact                 ==  note `A`
  1507   have "A ==> B" by fact           ==  note `A ==> B`
  1508   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1509   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1510 
  1511 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1512 outer syntax.  Thus symbolic identifiers may be used without
  1513 additional white space in declarations like this: ``assume *: A''.
  1514 
  1515 * Isar: 'print_facts' prints all local facts of the current context,
  1516 both named and unnamed ones.
  1517 
  1518 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1519 
  1520   def x == "t" and y == "u"
  1521 
  1522 * Isar: added command 'unfolding', which is structurally similar to
  1523 'using', but affects both the goal state and facts by unfolding given
  1524 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1525 'unfolded' attribute may be replaced by first-class proof text.
  1526 
  1527 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1528 and command 'unfolding' now all support object-level equalities
  1529 (potentially conditional).  The underlying notion of rewrite rule is
  1530 analogous to the 'rule_format' attribute, but *not* that of the
  1531 Simplifier (which is usually more generous).
  1532 
  1533 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1534 premises of a theorem by n. Useful in conjunction with drule.
  1535 
  1536 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1537 method expression within a sandbox consisting of the first N
  1538 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1539 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1540 simplifies all new goals that emerge from applying rule foo to the
  1541 originally first one.
  1542 
  1543 * Isar: schematic goals are no longer restricted to higher-order
  1544 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1545 expected.
  1546 
  1547 * Isar: the conclusion of a long theorem statement is now either
  1548 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1549 (essentially a disjunction of cases with local parameters and
  1550 assumptions).  The latter allows to express general elimination rules
  1551 adequately; in this notation common elimination rules look like this:
  1552 
  1553   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1554     assumes "EX x. P x"
  1555     obtains x where "P x"
  1556 
  1557   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1558     assumes "A & B"
  1559     obtains A and B
  1560 
  1561   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1562     assumes "A | B"
  1563     obtains
  1564       A
  1565     | B
  1566 
  1567 The subsequent classical rules even refer to the formal "thesis"
  1568 explicitly:
  1569 
  1570   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1571     obtains "~ thesis"
  1572 
  1573   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1574     obtains "thesis ==> something"
  1575 
  1576 The actual proof of an 'obtains' statement is analogous to that of the
  1577 Isar proof element 'obtain', only that there may be several cases.
  1578 Optional case names may be specified in parentheses; these will be
  1579 available both in the present proof and as annotations in the
  1580 resulting rule, for later use with the 'cases' method (cf. attribute
  1581 case_names).
  1582 
  1583 * Isar: the assumptions of a long theorem statement are available as
  1584 "assms" fact in the proof context.  This is more appropriate than the
  1585 (historical) "prems", which refers to all assumptions of the current
  1586 context, including those from the target locale, proof body etc.
  1587 
  1588 * Isar: 'print_statement' prints theorems from the current theory or
  1589 proof context in long statement form, according to the syntax of a
  1590 top-level lemma.
  1591 
  1592 * Isar: 'obtain' takes an optional case name for the local context
  1593 introduction rule (default "that").
  1594 
  1595 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1596 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1597 to occur.
  1598 
  1599 * Pure: syntax "CONST name" produces a fully internalized constant
  1600 according to the current context.  This is particularly useful for
  1601 syntax translations that should refer to internal constant
  1602 representations independently of name spaces.
  1603 
  1604 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1605 instead of "FOO ". This allows multiple binder declarations to coexist
  1606 in the same context.  INCOMPATIBILITY.
  1607 
  1608 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1609 primitive that also works in a locale context (both for constants and
  1610 fixed variables). Type declaration and internal syntactic representation
  1611 of given constants retrieved from the context. Likewise, the
  1612 'no_notation' command allows to remove given syntax annotations from the
  1613 current context.
  1614 
  1615 * Isar/locales: new derived specification elements 'axiomatization',
  1616 'definition', 'abbreviation', which support type-inference, admit
  1617 object-level specifications (equality, equivalence).  See also the
  1618 isar-ref manual.  Examples:
  1619 
  1620   axiomatization
  1621     eq  (infix "===" 50) where
  1622     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1623 
  1624   definition "f x y = x + y + 1"
  1625   definition g where "g x = f x x"
  1626 
  1627   abbreviation
  1628     neq  (infix "=!=" 50) where
  1629     "x =!= y == ~ (x === y)"
  1630 
  1631 These specifications may be also used in a locale context.  Then the
  1632 constants being introduced depend on certain fixed parameters, and the
  1633 constant name is qualified by the locale base name.  An internal
  1634 abbreviation takes care for convenient input and output, making the
  1635 parameters implicit and using the original short name.  See also
  1636 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1637 entities from a monomorphic theory.
  1638 
  1639 Presently, abbreviations are only available 'in' a target locale, but
  1640 not inherited by general import expressions.  Also note that
  1641 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1642 'translations' in common applications.  The "no_abbrevs" print mode
  1643 prevents folding of abbreviations in term output.
  1644 
  1645 Concrete syntax is attached to specified constants in internal form,
  1646 independently of name spaces.  The parse tree representation is
  1647 slightly different -- use 'notation' instead of raw 'syntax', and
  1648 'translations' with explicit "CONST" markup to accommodate this.
  1649 
  1650 * Pure/Isar: unified syntax for new-style specification mechanisms
  1651 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1652 full type inference and dummy patterns ("_").  For example:
  1653 
  1654   definition "K x _ = x"
  1655 
  1656   inductive conj for A B
  1657   where "A ==> B ==> conj A B"
  1658 
  1659 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1660 the current context.  Print mode "no_abbrevs" prevents inversion of
  1661 abbreviations on output.
  1662 
  1663 * Isar/locales: improved parameter handling: use of locales "var" and
  1664 "struct" no longer necessary; - parameter renamings are no longer
  1665 required to be injective.  For example, this allows to define
  1666 endomorphisms as locale endom = homom mult mult h.
  1667 
  1668 * Isar/locales: changed the way locales with predicates are defined.
  1669 Instead of accumulating the specification, the imported expression is
  1670 now an interpretation.  INCOMPATIBILITY: different normal form of
  1671 locale expressions.  In particular, in interpretations of locales with
  1672 predicates, goals repesenting already interpreted fragments are not
  1673 removed automatically.  Use methods `intro_locales' and
  1674 `unfold_locales'; see below.
  1675 
  1676 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1677 provide backward reasoning on locales predicates.  The methods are
  1678 aware of interpretations and discharge corresponding goals.
  1679 `intro_locales' is less aggressive then `unfold_locales' and does not
  1680 unfold predicates to assumptions.
  1681 
  1682 * Isar/locales: the order in which locale fragments are accumulated
  1683 has changed.  This enables to override declarations from fragments due
  1684 to interpretations -- for example, unwanted simp rules.
  1685 
  1686 * Isar/locales: interpretation in theories and proof contexts has been
  1687 extended.  One may now specify (and prove) equations, which are
  1688 unfolded in interpreted theorems.  This is useful for replacing
  1689 defined concepts (constants depending on locale parameters) by
  1690 concepts already existing in the target context.  Example:
  1691 
  1692   interpretation partial_order ["op <= :: [int, int] => bool"]
  1693     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1694 
  1695 Typically, the constant `partial_order.less' is created by a
  1696 definition specification element in the context of locale
  1697 partial_order.
  1698 
  1699 * Method "induct": improved internal context management to support
  1700 local fixes and defines on-the-fly. Thus explicit meta-level
  1701 connectives !!  and ==> are rarely required anymore in inductive goals
  1702 (using object-logic connectives for this purpose has been long
  1703 obsolete anyway). Common proof patterns are explained in
  1704 src/HOL/Induct/Common_Patterns.thy, see also
  1705 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1706 examples.
  1707 
  1708 * Method "induct": improved handling of simultaneous goals. Instead of
  1709 introducing object-level conjunction, the statement is now split into
  1710 several conclusions, while the corresponding symbolic cases are nested
  1711 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1712 see src/HOL/Induct/Common_Patterns.thy, for example.
  1713 
  1714 * Method "induct": mutual induction rules are now specified as a list
  1715 of rule sharing the same induction cases. HOL packages usually provide
  1716 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1717 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1718 mutual induction rules differently, i.e. like this:
  1719 
  1720   (induct rule: foo_bar.inducts)
  1721   (induct set: foo bar)
  1722   (induct pred: foo bar)
  1723   (induct type: foo bar)
  1724 
  1725 The ML function ProjectRule.projections turns old-style rules into the
  1726 new format.
  1727 
  1728 * Method "coinduct": dual of induction, see
  1729 src/HOL/Library/Coinductive_List.thy for various examples.
  1730 
  1731 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1732 considered a legacy feature.
  1733 
  1734 * Attribute "symmetric" produces result with standardized schematic
  1735 variables (index 0).  Potential INCOMPATIBILITY.
  1736 
  1737 * Simplifier: by default the simplifier trace only shows top level
  1738 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1739 default. Thus there is less danger of being flooded by the trace. The
  1740 trace indicates where parts have been suppressed.
  1741   
  1742 * Provers/classical: removed obsolete classical version of elim_format
  1743 attribute; classical elim/dest rules are now treated uniformly when
  1744 manipulating the claset.
  1745 
  1746 * Provers/classical: stricter checks to ensure that supplied intro,
  1747 dest and elim rules are well-formed; dest and elim rules must have at
  1748 least one premise.
  1749 
  1750 * Provers/classical: attributes dest/elim/intro take an optional
  1751 weight argument for the rule (just as the Pure versions).  Weights are
  1752 ignored by automated tools, but determine the search order of single
  1753 rule steps.
  1754 
  1755 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1756 where the body does not mention the bound variable.  Note that dummy
  1757 patterns implicitly depend on their context of bounds, which makes
  1758 "{_. _}" match any set comprehension as expected.  Potential
  1759 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1760 constant "_idtdummy" in the binding position.
  1761 
  1762 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1763 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1764 for example "A -> B" => "Pi A (%_. B)".
  1765 
  1766 * Pure: 'class_deps' command visualizes the subclass relation, using
  1767 the graph browser tool.
  1768 
  1769 * Pure: 'print_theory' now suppresses certain internal declarations by
  1770 default; use '!' option for full details.
  1771 
  1772 
  1773 *** HOL ***
  1774 
  1775 * Method "metis" proves goals by applying the Metis general-purpose
  1776 resolution prover (see also http://gilith.com/software/metis/).
  1777 Examples are in the directory MetisExamples.  WARNING: the
  1778 Isabelle/HOL-Metis integration does not yet work properly with
  1779 multi-threading.
  1780   
  1781 * Command 'sledgehammer' invokes external automatic theorem provers as
  1782 background processes.  It generates calls to the "metis" method if
  1783 successful. These can be pasted into the proof.  Users do not have to
  1784 wait for the automatic provers to return.  WARNING: does not really
  1785 work with multi-threading.
  1786 
  1787 * New "auto_quickcheck" feature tests outermost goal statements for
  1788 potential counter-examples.  Controlled by ML references
  1789 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1790 5000 milliseconds).  Fails silently if statements is outside of
  1791 executable fragment, or any other codgenerator problem occurs.
  1792 
  1793 * New constant "undefined" with axiom "undefined x = undefined".
  1794 
  1795 * Added class "HOL.eq", allowing for code generation with polymorphic
  1796 equality.
  1797 
  1798 * Some renaming of class constants due to canonical name prefixing in
  1799 the new 'class' package:
  1800 
  1801     HOL.abs ~> HOL.abs_class.abs
  1802     HOL.divide ~> HOL.divide_class.divide
  1803     0 ~> HOL.zero_class.zero
  1804     1 ~> HOL.one_class.one
  1805     op + ~> HOL.plus_class.plus
  1806     op - ~> HOL.minus_class.minus
  1807     uminus ~> HOL.minus_class.uminus
  1808     op * ~> HOL.times_class.times
  1809     op < ~> HOL.ord_class.less
  1810     op <= > HOL.ord_class.less_eq
  1811     Nat.power ~> Power.power_class.power
  1812     Nat.size ~> Nat.size_class.size
  1813     Numeral.number_of ~> Numeral.number_class.number_of
  1814     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1815     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1816     Orderings.min ~> Orderings.ord_class.min
  1817     Orderings.max ~> Orderings.ord_class.max
  1818     Divides.op div ~> Divides.div_class.div
  1819     Divides.op mod ~> Divides.div_class.mod
  1820     Divides.op dvd ~> Divides.div_class.dvd
  1821 
  1822 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1823 
  1824 a) User-defined constants using any of the names "plus", "minus",
  1825 "times", "less" or "less_eq". The standard syntax translations for
  1826 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1827 names.
  1828 
  1829 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1830 INCOMPATIBILITY: use more specific names.
  1831 
  1832 c) Permutative equations (e.g. "a + b = b + a")
  1833 Since the change of names also changes the order of terms, permutative
  1834 rewrite rules may get applied in a different order. Experience shows
  1835 that this is rarely the case (only two adaptions in the whole Isabelle
  1836 distribution).  INCOMPATIBILITY: rewrite proofs
  1837 
  1838 d) ML code directly refering to constant names
  1839 This in general only affects hand-written proof tactics, simprocs and
  1840 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1841 Consider using @{const_name} antiquotation.
  1842 
  1843 * New class "default" with associated constant "default".
  1844 
  1845 * Function "sgn" is now overloaded and available on int, real, complex
  1846 (and other numeric types), using class "sgn".  Two possible defs of
  1847 sgn are given as equational assumptions in the classes sgn_if and
  1848 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1849 INCOMPATIBILITY.
  1850 
  1851 * Locale "partial_order" now unified with class "order" (cf. theory
  1852 Orderings), added parameter "less".  INCOMPATIBILITY.
  1853 
  1854 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1855 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1856 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1857 
  1858 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1859 changed order of proof goals in instance proofs.
  1860 
  1861 * The transitivity reasoner for partial and linear orders is set up
  1862 for classes "order" and "linorder".  Instances of the reasoner are available
  1863 in all contexts importing or interpreting the corresponding locales.
  1864 Method "order" invokes the reasoner separately; the reasoner
  1865 is also integrated with the Simplifier as a solver.  Diagnostic
  1866 command 'print_orders' shows the available instances of the reasoner
  1867 in the current context.
  1868 
  1869 * Localized monotonicity predicate in theory "Orderings"; integrated
  1870 lemmas max_of_mono and min_of_mono with this predicate.
  1871 INCOMPATIBILITY.
  1872 
  1873 * Formulation of theorem "dense" changed slightly due to integration
  1874 with new class dense_linear_order.
  1875 
  1876 * Uniform lattice theory development in HOL.
  1877 
  1878     constants "meet" and "join" now named "inf" and "sup"
  1879     constant "Meet" now named "Inf"
  1880 
  1881     classes "meet_semilorder" and "join_semilorder" now named
  1882       "lower_semilattice" and "upper_semilattice"
  1883     class "lorder" now named "lattice"
  1884     class "comp_lat" now named "complete_lattice"
  1885 
  1886     Instantiation of lattice classes allows explicit definitions
  1887     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1888 
  1889   INCOMPATIBILITY.  Theorem renames:
  1890 
  1891     meet_left_le            ~> inf_le1
  1892     meet_right_le           ~> inf_le2
  1893     join_left_le            ~> sup_ge1
  1894     join_right_le           ~> sup_ge2
  1895     meet_join_le            ~> inf_sup_ord
  1896     le_meetI                ~> le_infI
  1897     join_leI                ~> le_supI
  1898     le_meet                 ~> le_inf_iff
  1899     le_join                 ~> ge_sup_conv
  1900     meet_idempotent         ~> inf_idem
  1901     join_idempotent         ~> sup_idem
  1902     meet_comm               ~> inf_commute
  1903     join_comm               ~> sup_commute
  1904     meet_leI1               ~> le_infI1
  1905     meet_leI2               ~> le_infI2
  1906     le_joinI1               ~> le_supI1
  1907     le_joinI2               ~> le_supI2
  1908     meet_assoc              ~> inf_assoc
  1909     join_assoc              ~> sup_assoc
  1910     meet_left_comm          ~> inf_left_commute
  1911     meet_left_idempotent    ~> inf_left_idem
  1912     join_left_comm          ~> sup_left_commute
  1913     join_left_idempotent    ~> sup_left_idem
  1914     meet_aci                ~> inf_aci
  1915     join_aci                ~> sup_aci
  1916     le_def_meet             ~> le_iff_inf
  1917     le_def_join             ~> le_iff_sup
  1918     join_absorp2            ~> sup_absorb2
  1919     join_absorp1            ~> sup_absorb1
  1920     meet_absorp1            ~> inf_absorb1
  1921     meet_absorp2            ~> inf_absorb2
  1922     meet_join_absorp        ~> inf_sup_absorb
  1923     join_meet_absorp        ~> sup_inf_absorb
  1924     distrib_join_le         ~> distrib_sup_le
  1925     distrib_meet_le         ~> distrib_inf_le
  1926 
  1927     add_meet_distrib_left   ~> add_inf_distrib_left
  1928     add_join_distrib_left   ~> add_sup_distrib_left
  1929     is_join_neg_meet        ~> is_join_neg_inf
  1930     is_meet_neg_join        ~> is_meet_neg_sup
  1931     add_meet_distrib_right  ~> add_inf_distrib_right
  1932     add_join_distrib_right  ~> add_sup_distrib_right
  1933     add_meet_join_distribs  ~> add_sup_inf_distribs
  1934     join_eq_neg_meet        ~> sup_eq_neg_inf
  1935     meet_eq_neg_join        ~> inf_eq_neg_sup
  1936     add_eq_meet_join        ~> add_eq_inf_sup
  1937     meet_0_imp_0            ~> inf_0_imp_0
  1938     join_0_imp_0            ~> sup_0_imp_0
  1939     meet_0_eq_0             ~> inf_0_eq_0
  1940     join_0_eq_0             ~> sup_0_eq_0
  1941     neg_meet_eq_join        ~> neg_inf_eq_sup
  1942     neg_join_eq_meet        ~> neg_sup_eq_inf
  1943     join_eq_if              ~> sup_eq_if
  1944 
  1945     mono_meet               ~> mono_inf
  1946     mono_join               ~> mono_sup
  1947     meet_bool_eq            ~> inf_bool_eq
  1948     join_bool_eq            ~> sup_bool_eq
  1949     meet_fun_eq             ~> inf_fun_eq
  1950     join_fun_eq             ~> sup_fun_eq
  1951     meet_set_eq             ~> inf_set_eq
  1952     join_set_eq             ~> sup_set_eq
  1953     meet1_iff               ~> inf1_iff
  1954     meet2_iff               ~> inf2_iff
  1955     meet1I                  ~> inf1I
  1956     meet2I                  ~> inf2I
  1957     meet1D1                 ~> inf1D1
  1958     meet2D1                 ~> inf2D1
  1959     meet1D2                 ~> inf1D2
  1960     meet2D2                 ~> inf2D2
  1961     meet1E                  ~> inf1E
  1962     meet2E                  ~> inf2E
  1963     join1_iff               ~> sup1_iff
  1964     join2_iff               ~> sup2_iff
  1965     join1I1                 ~> sup1I1
  1966     join2I1                 ~> sup2I1
  1967     join1I1                 ~> sup1I1
  1968     join2I2                 ~> sup1I2
  1969     join1CI                 ~> sup1CI
  1970     join2CI                 ~> sup2CI
  1971     join1E                  ~> sup1E
  1972     join2E                  ~> sup2E
  1973 
  1974     is_meet_Meet            ~> is_meet_Inf
  1975     Meet_bool_def           ~> Inf_bool_def
  1976     Meet_fun_def            ~> Inf_fun_def
  1977     Meet_greatest           ~> Inf_greatest
  1978     Meet_lower              ~> Inf_lower
  1979     Meet_set_def            ~> Inf_set_def
  1980 
  1981     Sup_def                 ~> Sup_Inf
  1982     Sup_bool_eq             ~> Sup_bool_def
  1983     Sup_fun_eq              ~> Sup_fun_def
  1984     Sup_set_eq              ~> Sup_set_def
  1985 
  1986     listsp_meetI            ~> listsp_infI
  1987     listsp_meet_eq          ~> listsp_inf_eq
  1988 
  1989     meet_min                ~> inf_min
  1990     join_max                ~> sup_max
  1991 
  1992 * Added syntactic class "size"; overloaded constant "size" now has
  1993 type "'a::size ==> bool"
  1994 
  1995 * Internal reorganisation of `size' of datatypes: size theorems
  1996 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1997 simplification rules by default!); theorems "prod.size" now named
  1998 "*.size".
  1999 
  2000 * Class "div" now inherits from class "times" rather than "type".
  2001 INCOMPATIBILITY.
  2002 
  2003 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2004 Linorder etc.  have disappeared; operations defined in terms of
  2005 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2006 
  2007 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2008 
  2009 * HOL-Word: New extensive library and type for generic, fixed size
  2010 machine words, with arithemtic, bit-wise, shifting and rotating
  2011 operations, reflection into int, nat, and bool lists, automation for
  2012 linear arithmetic (by automatic reflection into nat or int), including
  2013 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2014 arithmetic type classes, supporting automatic simplification of
  2015 numerals on all operations.
  2016 
  2017 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2018 
  2019 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2020 
  2021 * Code generator library theories:
  2022   - Code_Integer represents HOL integers by big integer literals in target
  2023     languages.
  2024   - Code_Char represents HOL characters by character literals in target
  2025     languages.
  2026   - Code_Char_chr like Code_Char, but also offers treatment of character
  2027     codes; includes Code_Integer.
  2028   - Executable_Set allows to generate code for finite sets using lists.
  2029   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2030     denominator).
  2031   - Executable_Real implements a subset of real numbers, namly those
  2032     representable by rational numbers.
  2033   - Efficient_Nat implements natural numbers by integers, which in general will
  2034     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2035     includes Code_Integer.
  2036   - Code_Index provides an additional datatype index which is mapped to
  2037     target-language built-in integers.
  2038   - Code_Message provides an additional datatype message_string which is isomorphic to
  2039     strings; messages are mapped to target-language strings.
  2040 
  2041 * New package for inductive predicates
  2042 
  2043   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2044 
  2045     inductive
  2046       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2047       for z_1 :: U_1 and ... and z_n :: U_m
  2048     where
  2049       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2050     | ...
  2051 
  2052   with full support for type-inference, rather than
  2053 
  2054     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2055 
  2056     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2057     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2058 
  2059     inductive "s z_1 ... z_m"
  2060     intros
  2061       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2062       ...
  2063 
  2064   For backward compatibility, there is a wrapper allowing inductive
  2065   sets to be defined with the new package via
  2066 
  2067     inductive_set
  2068       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2069       for z_1 :: U_1 and ... and z_n :: U_m
  2070     where
  2071       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2072     | ...
  2073 
  2074   or
  2075 
  2076     inductive_set
  2077       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2078       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2079       for z_1 :: U_1 and ... and z_n :: U_m
  2080     where
  2081       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2082     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2083     | ...
  2084 
  2085   if the additional syntax "p ..." is required.
  2086 
  2087   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2088   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2089 
  2090   INCOMPATIBILITIES:
  2091 
  2092   - Since declaration and definition of inductive sets or predicates
  2093     is no longer separated, abbreviations involving the newly
  2094     introduced sets or predicates must be specified together with the
  2095     introduction rules after the 'where' keyword (see above), rather
  2096     than before the actual inductive definition.
  2097 
  2098   - The variables in induction and elimination rules are now
  2099     quantified in the order of their occurrence in the introduction
  2100     rules, rather than in alphabetical order. Since this may break
  2101     some proofs, these proofs either have to be repaired, e.g. by
  2102     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2103     statements of the form
  2104 
  2105       case (rule_i a_i_1 ... a_i_{k_i})
  2106 
  2107     or the old order of quantification has to be restored by explicitly adding
  2108     meta-level quantifiers in the introduction rules, i.e.
  2109 
  2110       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2111 
  2112   - The format of the elimination rules is now
  2113 
  2114       p z_1 ... z_m x_1 ... x_n ==>
  2115         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2116         ==> ... ==> P
  2117 
  2118     for predicates and
  2119 
  2120       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2121         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2122         ==> ... ==> P
  2123 
  2124     for sets rather than
  2125 
  2126       x : s z_1 ... z_m ==>
  2127         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2128         ==> ... ==> P
  2129 
  2130     This may require terms in goals to be expanded to n-tuples
  2131     (e.g. using case_tac or simplification with the split_paired_all
  2132     rule) before the above elimination rule is applicable.
  2133 
  2134   - The elimination or case analysis rules for (mutually) inductive
  2135     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2136     list of rules "p_1_..._p_k.elims" is no longer available.
  2137 
  2138 * New package "function"/"fun" for general recursive functions,
  2139 supporting mutual and nested recursion, definitions in local contexts,
  2140 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2141 for small examples, and the separate tutorial on the function
  2142 package. The old recdef "package" is still available as before, but
  2143 users are encouraged to use the new package.
  2144 
  2145 * Method "lexicographic_order" automatically synthesizes termination
  2146 relations as lexicographic combinations of size measures. 
  2147 
  2148 * Case-expressions allow arbitrary constructor-patterns (including
  2149 "_") and take their order into account, like in functional
  2150 programming.  Internally, this is translated into nested
  2151 case-expressions; missing cases are added and mapped to the predefined
  2152 constant "undefined". In complicated cases printing may no longer show
  2153 the original input but the internal form. Lambda-abstractions allow
  2154 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2155 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2156 variable.
  2157 
  2158 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2159 is an abbreviation for "of_nat :: nat => int". The simplification
  2160 rules for "of_nat" have been changed to work like "int" did
  2161 previously.  Potential INCOMPATIBILITY:
  2162   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2163   - of_nat_diff and of_nat_mult are no longer default simp rules
  2164 
  2165 * Method "algebra" solves polynomial equations over (semi)rings using
  2166 Groebner bases. The (semi)ring structure is defined by locales and the
  2167 tool setup depends on that generic context. Installing the method for
  2168 a specific type involves instantiating the locale and possibly adding
  2169 declarations for computation on the coefficients.  The method is
  2170 already instantiated for natural numbers and for the axiomatic class
  2171 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2172 CALCULEMUS 2007 for the general principles underlying this
  2173 architecture of context-aware proof-tools.
  2174 
  2175 * Method "ferrack" implements quantifier elimination over
  2176 special-purpose dense linear orders using locales (analogous to
  2177 "algebra"). The method is already installed for class
  2178 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2179 rat, etc.
  2180 
  2181 * Former constant "List.op @" now named "List.append".  Use ML
  2182 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2183 circumvent possible incompatibilities when working on ML level.
  2184 
  2185 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2186 
  2187 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2188 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2189 
  2190 * New syntax for Haskell-like list comprehension (input only), eg.
  2191 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2192 
  2193 * The special syntax for function "filter" has changed from [x :
  2194 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2195 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2196 
  2197 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2198 defined on nat only, as an abbreviation for [a..<Suc b]
  2199 INCOMPATIBILITY.
  2200 
  2201 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2202 
  2203 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2204 
  2205 * New lemma collection field_simps (an extension of ring_simps) for
  2206 manipulating (in)equations involving division. Multiplies with all
  2207 denominators that can be proved to be non-zero (in equations) or
  2208 positive/negative (in inequations).
  2209 
  2210 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2211 have been improved and renamed to ring_simps, group_simps and
  2212 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2213 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2214 
  2215 * Theory Library/Commutative_Ring: switched from recdef to function
  2216 package; constants add, mul, pow now curried.  Infix syntax for
  2217 algebraic operations.
  2218 
  2219 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2220 INCOMPATIBILITY.
  2221 
  2222 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2223 INCOMPATIBILITY.
  2224 
  2225 * HOL/records: generalised field-update to take a function on the
  2226 field rather than the new value: r(|A := x|) is translated to A_update
  2227 (K x) r The K-combinator that is internally used is called K_record.
  2228 INCOMPATIBILITY: Usage of the plain update functions has to be
  2229 adapted.
  2230  
  2231 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2232 * x = 0, which are required for a semiring.  Richer structures do not
  2233 inherit from semiring_0 anymore, because this property is a theorem
  2234 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2235 there is more to prove, but this is mostly trivial.
  2236 
  2237 * Class "recpower" is generalized to arbitrary monoids, not just
  2238 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2239 commutativity or semiring properties additionally.
  2240 
  2241 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2242 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2243 better use 'abbreviation'.
  2244 
  2245 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2246 
  2247 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2248 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2249 significant changes for setting up numeral syntax for types:
  2250   - New constants Numeral.pred and Numeral.succ instead
  2251       of former Numeral.bin_pred and Numeral.bin_succ.
  2252   - Use integer operations instead of bin_add, bin_mult and so on.
  2253   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2254   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2255 
  2256 See src/HOL/Integ/IntArith.thy for an example setup.
  2257 
  2258 * Command 'normal_form' computes the normal form of a term that may
  2259 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2260 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2261 heavy-duty computations because the functions are compiled to ML
  2262 first.  Correspondingly, a method "normalization" is provided.  See
  2263 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2264 
  2265 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2266 25 like -->); output depends on the "iff" print_mode, the default is
  2267 "A = B" (with priority 50).
  2268 
  2269 * Relations less (<) and less_eq (<=) are also available on type bool.
  2270 Modified syntax to disallow nesting without explicit parentheses,
  2271 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2272 INCOMPATIBILITY.
  2273 
  2274 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2275 
  2276 * Relation composition operator "op O" now has precedence 75 and binds
  2277 stronger than union and intersection. INCOMPATIBILITY.
  2278 
  2279 * The old set interval syntax "{m..n(}" (and relatives) has been
  2280 removed.  Use "{m..<n}" (and relatives) instead.
  2281 
  2282 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2283 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2284 ``declare [[simproc del: neq]]''.
  2285 
  2286 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2287 True/False.
  2288 
  2289 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2290 
  2291 * Theorem setsum_mult renamed to setsum_right_distrib.
  2292 
  2293 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2294 ``rule'' method.
  2295 
  2296 * Reimplemented methods "sat" and "satx", with several improvements:
  2297 goals no longer need to be stated as "<prems> ==> False", equivalences
  2298 (i.e. "=" on type bool) are handled, variable names of the form
  2299 "lit_<n>" are no longer reserved, significant speedup.
  2300 
  2301 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2302 zChaff is still supported as well.
  2303 
  2304 * 'inductive' and 'datatype': provide projections of mutual rules,
  2305 bundled as foo_bar.inducts;
  2306 
  2307 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2308 Library.
  2309 
  2310 * Library: moved theory Accessible_Part to main HOL.
  2311 
  2312 * Library: added theory Coinductive_List of potentially infinite lists
  2313 as greatest fixed-point.
  2314 
  2315 * Library: added theory AssocList which implements (finite) maps as
  2316 association lists.
  2317 
  2318 * Method "evaluation" solves goals (i.e. a boolean expression)
  2319 efficiently by compiling it to ML.  The goal is "proved" (via an
  2320 oracle) if it evaluates to True.
  2321 
  2322 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2323 also when invoked by the simplifier.  This results in the Simplifier
  2324 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2325 Configuration option fast_arith_split_limit=0 recovers the old
  2326 behavior.
  2327 
  2328 * Support for hex (0x20) and binary (0b1001) numerals.
  2329 
  2330 * New method: reify eqs (t), where eqs are equations for an
  2331 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2332 parameter, computes a term s::'b and a list xs::'a list and proves the
  2333 theorem I xs s = t. This is also known as reification or quoting. The
  2334 resulting theorem is applied to the subgoal to substitute t with I xs
  2335 s.  If t is omitted, the subgoal itself is reified.
  2336 
  2337 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2338 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2339 where f is supposed to be a computable function (in the sense of code
  2340 generattion). The method uses reify to compute s and xs as above then
  2341 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2342 r and finally gets the theorem t = r, which is again applied to the
  2343 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2344 
  2345 * Reflection: Automatic reification now handels binding, an example is
  2346 available in src/HOL/ex/ReflectionEx.thy
  2347 
  2348 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2349 command 'statespace' that is similar to 'record', but introduces an
  2350 abstract specification based on the locale infrastructure instead of
  2351 HOL types.  This leads to extra flexibility in composing state spaces,
  2352 in particular multiple inheritance and renaming of components.
  2353 
  2354 
  2355 *** HOL-Complex ***
  2356 
  2357 * Hyperreal: Functions root and sqrt are now defined on negative real
  2358 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2359 Nonnegativity side conditions have been removed from many lemmas, so
  2360 that more subgoals may now be solved by simplification; potential
  2361 INCOMPATIBILITY.
  2362 
  2363 * Real: new type classes formalize real normed vector spaces and
  2364 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2365 and norm :: 'a => real.
  2366 
  2367 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2368 reals into other types. The overloaded constant Reals :: 'a set is now
  2369 defined as range of_real; potential INCOMPATIBILITY.
  2370 
  2371 * Real: proper support for ML code generation, including 'quickcheck'.
  2372 Reals are implemented as arbitrary precision rationals.
  2373 
  2374 * Hyperreal: Several constants that previously worked only for the
  2375 reals have been generalized, so they now work over arbitrary vector
  2376 spaces. Type annotations may need to be added in some cases; potential
  2377 INCOMPATIBILITY.
  2378 
  2379   Infinitesimal  :: ('a::real_normed_vector) star set
  2380   HFinite        :: ('a::real_normed_vector) star set
  2381   HInfinite      :: ('a::real_normed_vector) star set
  2382   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2383   monad          :: ('a::real_normed_vector) star => 'a star set
  2384   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2385   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2386   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2387   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2388   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2389   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2390   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2391   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2392   sgn            :: 'a::real_normed_vector => 'a
  2393   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2394 
  2395 * Complex: Some complex-specific constants are now abbreviations for
  2396 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2397 hnorm.  Other constants have been entirely removed in favor of the
  2398 polymorphic versions (INCOMPATIBILITY):
  2399 
  2400   approx        <-- capprox
  2401   HFinite       <-- CFinite
  2402   HInfinite     <-- CInfinite
  2403   Infinitesimal <-- CInfinitesimal
  2404   monad         <-- cmonad
  2405   galaxy        <-- cgalaxy
  2406   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2407   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2408   (ns)deriv     <-- (ns)cderiv
  2409 
  2410 
  2411 *** HOL-Algebra ***
  2412 
  2413 * Formalisation of ideals and the quotient construction over rings.
  2414 
  2415 * Order and lattice theory no longer based on records.
  2416 INCOMPATIBILITY.
  2417 
  2418 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2419 greatest_closed.  INCOMPATIBILITY.
  2420 
  2421 * Method algebra is now set up via an attribute.  For examples see
  2422 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2423 of algebraic structures.
  2424 
  2425 * Renamed theory CRing to Ring.
  2426 
  2427 
  2428 *** HOL-Nominal ***
  2429 
  2430 * Substantial, yet incomplete support for nominal datatypes (binding
  2431 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2432 src/HOL/Nominal/Examples.  Prospective users should consult
  2433 http://isabelle.in.tum.de/nominal/
  2434 
  2435 
  2436 *** ML ***
  2437 
  2438 * ML basics: just one true type int, which coincides with IntInf.int
  2439 (even on SML/NJ).
  2440 
  2441 * ML within Isar: antiquotations allow to embed statically-checked
  2442 formal entities in the source, referring to the context available at
  2443 compile-time.  For example:
  2444 
  2445 ML {* @{sort "{zero,one}"} *}
  2446 ML {* @{typ "'a => 'b"} *}
  2447 ML {* @{term "%x. x"} *}
  2448 ML {* @{prop "x == y"} *}
  2449 ML {* @{ctyp "'a => 'b"} *}
  2450 ML {* @{cterm "%x. x"} *}
  2451 ML {* @{cprop "x == y"} *}
  2452 ML {* @{thm asm_rl} *}
  2453 ML {* @{thms asm_rl} *}
  2454 ML {* @{type_name c} *}
  2455 ML {* @{type_syntax c} *}
  2456 ML {* @{const_name c} *}
  2457 ML {* @{const_syntax c} *}
  2458 ML {* @{context} *}
  2459 ML {* @{theory} *}
  2460 ML {* @{theory Pure} *}
  2461 ML {* @{theory_ref} *}
  2462 ML {* @{theory_ref Pure} *}
  2463 ML {* @{simpset} *}
  2464 ML {* @{claset} *}
  2465 ML {* @{clasimpset} *}
  2466 
  2467 The same works for sources being ``used'' within an Isar context.
  2468 
  2469 * ML in Isar: improved error reporting; extra verbosity with
  2470 ML_Context.trace enabled.
  2471 
  2472 * Pure/General/table.ML: the join operations now works via exceptions
  2473 DUP/SAME instead of type option. This is simpler in simple cases, and
  2474 admits slightly more efficient complex applications.
  2475 
  2476 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2477 use Context.generic instead of just theory.
  2478 
  2479 * Pure: datatype Context.generic joins theory/Proof.context and
  2480 provides some facilities for code that works in either kind of
  2481 context, notably GenericDataFun for uniform theory and proof data.
  2482 
  2483 * Pure: simplified internal attribute type, which is now always
  2484 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2485 local (Proof.context) attributes have been discontinued, while
  2486 minimizing code duplication. Thm.rule_attribute and
  2487 Thm.declaration_attribute build canonical attributes; see also structure
  2488 Context for further operations on Context.generic, notably
  2489 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2490 declarations and definitions.
  2491 
  2492 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2493 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2494 init only required for impure data. INCOMPATIBILITY: empty really need
  2495 to be empty (no dependencies on theory content!)
  2496 
  2497 * Pure/kernel: consts certification ignores sort constraints given in
  2498 signature declarations. (This information is not relevant to the
  2499 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2500 potential INCOMPATIBILITY.
  2501 
  2502 * Pure: axiomatic type classes are now purely definitional, with
  2503 explicit proofs of class axioms and super class relations performed
  2504 internally. See Pure/axclass.ML for the main internal interfaces --
  2505 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2506 AxClass.axiomatize_class/classrel/arity supersede
  2507 Sign.add_classes/classrel/arities.
  2508 
  2509 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2510 global/local versions on theory vs. Proof.context have been
  2511 discontinued; Attrib.syntax and Method.syntax have been adapted
  2512 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2513 attributes, methods, etc.
  2514 
  2515 * Pure: several functions of signature "... -> theory -> theory * ..."
  2516 have been reoriented to "... -> theory -> ... * theory" in order to
  2517 allow natural usage in combination with the ||>, ||>>, |-> and
  2518 fold_map combinators.
  2519 
  2520 * Pure: official theorem names (closed derivations) and additional
  2521 comments (tags) are now strictly separate.  Name hints -- which are
  2522 maintained as tags -- may be attached any time without affecting the
  2523 derivation.
  2524 
  2525 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2526 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2527 achieve the old behaviour.
  2528 
  2529 * Pure: the "Goal" constant is now called "prop", supporting a
  2530 slightly more general idea of ``protecting'' meta-level rule
  2531 statements.
  2532 
  2533 * Pure: Logic.(un)varify only works in a global context, which is now
  2534 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2535 Logic.legacy_(un)varify as temporary workaround.
  2536 
  2537 * Pure: structure Name provides scalable operations for generating
  2538 internal variable names, notably Name.variants etc.  This replaces
  2539 some popular functions from term.ML:
  2540 
  2541   Term.variant		->  Name.variant
  2542   Term.variantlist	->  Name.variant_list
  2543   Term.invent_names	->  Name.invent_list
  2544 
  2545 Note that low-level renaming rarely occurs in new code -- operations
  2546 from structure Variable are used instead (see below).
  2547 
  2548 * Pure: structure Variable provides fundamental operations for proper
  2549 treatment of fixed/schematic variables in a context.  For example,
  2550 Variable.import introduces fixes for schematics of given facts and
  2551 Variable.export reverses the effect (up to renaming) -- this replaces
  2552 various freeze_thaw operations.
  2553 
  2554 * Pure: structure Goal provides simple interfaces for
  2555 init/conclude/finish and tactical prove operations (replacing former
  2556 Tactic.prove).  Goal.prove is the canonical way to prove results
  2557 within a given context; Goal.prove_global is a degraded version for
  2558 theory level goals, including a global Drule.standard.  Note that
  2559 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2560 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2561 in a locale context).
  2562 
  2563 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2564 and type checking (Syntax.check_term etc.), with common combinations
  2565 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2566 which are considered legacy and await removal.
  2567 
  2568 * Pure/Syntax: generic interfaces for type unchecking
  2569 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2570 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2571 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2572 available for convenience, but refer to the very same operations using
  2573 a mere theory instead of a full context.
  2574 
  2575 * Isar: simplified treatment of user-level errors, using exception
  2576 ERROR of string uniformly.  Function error now merely raises ERROR,
  2577 without any side effect on output channels.  The Isar toplevel takes
  2578 care of proper display of ERROR exceptions.  ML code may use plain
  2579 handle/can/try; cat_error may be used to concatenate errors like this:
  2580 
  2581   ... handle ERROR msg => cat_error msg "..."
  2582 
  2583 Toplevel ML code (run directly or through the Isar toplevel) may be
  2584 embedded into the Isar toplevel with exception display/debug like
  2585 this:
  2586 
  2587   Isar.toplevel (fn () => ...)
  2588 
  2589 INCOMPATIBILITY, removed special transform_error facilities, removed
  2590 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2591 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2592 -- use plain ERROR instead.
  2593 
  2594 * Isar: theory setup now has type (theory -> theory), instead of a
  2595 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2596 
  2597 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2598 ProofContext.debug/verbose flags.
  2599 
  2600 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2601 theory before entering a proof state.  Transactions now always see a
  2602 quasi-functional intermediate checkpoint, both in interactive and
  2603 batch mode.
  2604 
  2605 * Isar: simplified interfaces for outer syntax.  Renamed
  2606 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2607 OuterSyntax.add_parsers -- this functionality is now included in
  2608 OuterSyntax.command etc.  INCOMPATIBILITY.
  2609 
  2610 * Simplifier: the simpset of a running simplification process now
  2611 contains a proof context (cf. Simplifier.the_context), which is the
  2612 very context that the initial simpset has been retrieved from (by
  2613 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2614 (solver, looper etc.) may depend on arbitrary proof data.
  2615 
  2616 * Simplifier.inherit_context inherits the proof context (plus the
  2617 local bounds) of the current simplification process; any simproc
  2618 etc. that calls the Simplifier recursively should do this!  Removed
  2619 former Simplifier.inherit_bounds, which is already included here --
  2620 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2621 specify an explicit context using Simplifier.context/theory_context.
  2622 
  2623 * Simplifier/Classical Reasoner: more abstract interfaces
  2624 change_simpset/claset for modifying the simpset/claset reference of a
  2625 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2626 INCOMPATIBILITY.
  2627 
  2628 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2629 "Trueprop" etc.
  2630 
  2631 
  2632 *** System ***
  2633 
  2634 * settings: the default heap location within ISABELLE_HOME_USER now
  2635 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2636 Isabelle installations.
  2637 
  2638 * isabelle-process: option -S (secure mode) disables some critical
  2639 operations, notably runtime compilation and evaluation of ML source
  2640 code.
  2641 
  2642 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2643 
  2644 * Support for parallel execution, using native multicore support of
  2645 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2646 independent theories, according to the given theory header
  2647 specifications. The maximum number of worker threads is specified via
  2648 usedir option -M or the "max-threads" setting in Proof General. A
  2649 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2650 to 6 on a 8-core machine.  User-code needs to observe certain
  2651 guidelines for thread-safe programming, see appendix A in the Isar
  2652 Implementation manual.
  2653 
  2654 
  2655 
  2656 New in Isabelle2005 (October 2005)
  2657 ----------------------------------
  2658 
  2659 *** General ***
  2660 
  2661 * Theory headers: the new header syntax for Isar theories is
  2662 
  2663   theory <name>
  2664   imports <theory1> ... <theoryN>
  2665   uses <file1> ... <fileM>
  2666   begin
  2667 
  2668 where the 'uses' part is optional.  The previous syntax
  2669 
  2670   theory <name> = <theory1> + ... + <theoryN>:
  2671 
  2672 will disappear in the next release.  Use isatool fixheaders to convert
  2673 existing theory files.  Note that there is no change in ancient
  2674 non-Isar theories now, but these will disappear soon.
  2675 
  2676 * Theory loader: parent theories can now also be referred to via
  2677 relative and absolute paths.
  2678 
  2679 * Command 'find_theorems' searches for a list of criteria instead of a
  2680 list of constants. Known criteria are: intro, elim, dest, name:string,
  2681 simp:term, and any term. Criteria can be preceded by '-' to select
  2682 theorems that do not match. Intro, elim, dest select theorems that
  2683 match the current goal, name:s selects theorems whose fully qualified
  2684 name contain s, and simp:term selects all simplification rules whose
  2685 lhs match term.  Any other term is interpreted as pattern and selects
  2686 all theorems matching the pattern. Available in ProofGeneral under
  2687 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2688 
  2689   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2690 
  2691 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2692 matching the current goal as introduction rule and not having "HOL."
  2693 in their name (i.e. not being defined in theory HOL).
  2694 
  2695 * Command 'thms_containing' has been discontinued in favour of
  2696 'find_theorems'; INCOMPATIBILITY.
  2697 
  2698 * Communication with Proof General is now 8bit clean, which means that
  2699 Unicode text in UTF-8 encoding may be used within theory texts (both
  2700 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2701 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2702 
  2703   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2704   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2705 
  2706 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2707 Classical Reasoner.  Typical big applications run around 2 times
  2708 faster.
  2709 
  2710 
  2711 *** Document preparation ***
  2712 
  2713 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2714 of raw sources.  Only those symbols that do not require additional
  2715 LaTeX packages (depending on comments in isabellesym.sty) are
  2716 displayed properly, everything else is left verbatim.  isatool display
  2717 and isatool print are used as front ends (these are subject to the
  2718 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2719 
  2720 * Command tags control specific markup of certain regions of text,
  2721 notably folding and hiding.  Predefined tags include "theory" (for
  2722 theory begin and end), "proof" for proof commands, and "ML" for
  2723 commands involving ML code; the additional tags "visible" and
  2724 "invisible" are unused by default.  Users may give explicit tag
  2725 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2726 interpretation of tags is determined by the LaTeX job during document
  2727 preparation: see option -V of isatool usedir, or options -n and -t of
  2728 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2729 \isadroptag.
  2730 
  2731 Several document versions may be produced at the same time via isatool
  2732 usedir (the generated index.html will link all of them).  Typical
  2733 specifications include ''-V document=theory,proof,ML'' to present
  2734 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2735 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2736 these parts without any formal replacement text.  The Isabelle site
  2737 default settings produce ''document'' and ''outline'' versions as
  2738 specified above.
  2739 
  2740 * Several new antiquotations:
  2741 
  2742   @{term_type term} prints a term with its type annotated;
  2743 
  2744   @{typeof term} prints the type of a term;
  2745 
  2746   @{const const} is the same as @{term const}, but checks that the
  2747   argument is a known logical constant;
  2748 
  2749   @{term_style style term} and @{thm_style style thm} print a term or
  2750   theorem applying a "style" to it
  2751 
  2752   @{ML text}
  2753 
  2754 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2755 definitions, equations, inequations etc., 'concl' printing only the
  2756 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2757 to print the specified premise.  TermStyle.add_style provides an ML
  2758 interface for introducing further styles.  See also the "LaTeX Sugar"
  2759 document practical applications.  The ML antiquotation prints
  2760 type-checked ML expressions verbatim.
  2761 
  2762 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2763 and 'text' support optional locale specification '(in loc)', which
  2764 specifies the default context for interpreting antiquotations.  For
  2765 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2766 
  2767 * Option 'locale=NAME' of antiquotations specifies an alternative
  2768 context interpreting the subsequent argument.  For example: @{thm
  2769 [locale=lattice] inf_assoc}.
  2770 
  2771 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2772 a proof context.
  2773 
  2774 * Proper output of antiquotations for theory commands involving a
  2775 proof context (such as 'locale' or 'theorem (in loc) ...').
  2776 
  2777 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2778 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2779 
  2780 * isatool usedir: new option -C (default true) controls whether option
  2781 -D should include a copy of the original document directory; -C false
  2782 prevents unwanted effects such as copying of administrative CVS data.
  2783 
  2784 
  2785 *** Pure ***
  2786 
  2787 * Considerably improved version of 'constdefs' command.  Now performs
  2788 automatic type-inference of declared constants; additional support for
  2789 local structure declarations (cf. locales and HOL records), see also
  2790 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2791 sequential dependencies of definitions within a single 'constdefs'
  2792 section; moreover, the declared name needs to be an identifier.  If
  2793 all fails, consider to fall back on 'consts' and 'defs' separately.
  2794 
  2795 * Improved indexed syntax and implicit structures.  First of all,
  2796 indexed syntax provides a notational device for subscripted
  2797 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2798 expressions.  Secondly, in a local context with structure
  2799 declarations, number indexes \<^sub>n or the empty index (default
  2800 number 1) refer to a certain fixed variable implicitly; option
  2801 show_structs controls printing of implicit structures.  Typical
  2802 applications of these concepts involve record types and locales.
  2803 
  2804 * New command 'no_syntax' removes grammar declarations (and
  2805 translations) resulting from the given syntax specification, which is
  2806 interpreted in the same manner as for the 'syntax' command.
  2807 
  2808 * 'Advanced' translation functions (parse_translation etc.) may depend
  2809 on the signature of the theory context being presently used for
  2810 parsing/printing, see also isar-ref manual.
  2811 
  2812 * Improved 'oracle' command provides a type-safe interface to turn an
  2813 ML expression of type theory -> T -> term into a primitive rule of
  2814 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2815 is already included here); see also FOL/ex/IffExample.thy;
  2816 INCOMPATIBILITY.
  2817 
  2818 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2819 before); "cI" is no longer bound, use "c.intro" instead.
  2820 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2821 axclasses vs. locales.
  2822 
  2823 * Improved internal renaming of symbolic identifiers -- attach primes
  2824 instead of base 26 numbers.
  2825 
  2826 * New flag show_question_marks controls printing of leading question
  2827 marks in schematic variable names.
  2828 
  2829 * In schematic variable names, *any* symbol following \<^isub> or
  2830 \<^isup> is now treated as part of the base name.  For example, the
  2831 following works without printing of awkward ".0" indexes:
  2832 
  2833   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2834     by simp
  2835 
  2836 * Inner syntax includes (*(*nested*) comments*).
  2837 
  2838 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2839 annotations as "(00...)".
  2840 
  2841 * Clear separation of logical types and nonterminals, where the latter
  2842 may only occur in 'syntax' specifications or type abbreviations.
  2843 Before that distinction was only partially implemented via type class
  2844 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2845 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2846 exotic syntax specifications may require further adaption
  2847 (e.g. Cube/Cube.thy).
  2848 
  2849 * Removed obsolete type class "logic", use the top sort {} instead.
  2850 Note that non-logical types should be declared as 'nonterminals'
  2851 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2852 specifications.
  2853 
  2854 * Attributes 'induct' and 'cases': type or set names may now be
  2855 locally fixed variables as well.
  2856 
  2857 * Simplifier: can now control the depth to which conditional rewriting
  2858 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2859 Limit.
  2860 
  2861 * Simplifier: simplification procedures may now take the current
  2862 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2863 interface), which is very useful for calling the Simplifier
  2864 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2865 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2866 low-level mk_simproc no longer applies Logic.varify internally, to
  2867 allow for use in a context of fixed variables.
  2868 
  2869 * thin_tac now works even if the assumption being deleted contains !!
  2870 or ==>.  More generally, erule now works even if the major premise of
  2871 the elimination rule contains !! or ==>.
  2872 
  2873 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2874 
  2875 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2876 from Pure, which contains all common declarations already.  Both
  2877 theories are defined via plain Isabelle/Isar .thy files.
  2878 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2879 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2880 use isatool fixcpure to adapt your theory and ML sources.
  2881 
  2882 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2883 selections of theorems in named facts via index ranges.
  2884 
  2885 * 'print_theorems': in theory mode, really print the difference
  2886 wrt. the last state (works for interactive theory development only),
  2887 in proof mode print all local facts (cf. 'print_facts');
  2888 
  2889 * 'hide': option '(open)' hides only base names.
  2890 
  2891 * More efficient treatment of intermediate checkpoints in interactive
  2892 theory development.
  2893 
  2894 * Code generator is now invoked via code_module (incremental code
  2895 generation) and code_library (modular code generation, ML structures
  2896 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2897 must be quoted when used as identifiers.
  2898 
  2899 * New 'value' command for reading, evaluating and printing terms using
  2900 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2901 quoted when used as identifier.
  2902 
  2903 
  2904 *** Locales ***
  2905 
  2906 * New commands for the interpretation of locale expressions in
  2907 theories (1), locales (2) and proof contexts (3).  These generate
  2908 proof obligations from the expression specification.  After the
  2909 obligations have been discharged, theorems of the expression are added
  2910 to the theory, target locale or proof context.  The synopsis of the
  2911 commands is a follows:
  2912 
  2913   (1) interpretation expr inst
  2914   (2) interpretation target < expr
  2915   (3) interpret expr inst
  2916 
  2917 Interpretation in theories and proof contexts require a parameter
  2918 instantiation of terms from the current context.  This is applied to
  2919 specifications and theorems of the interpreted expression.
  2920 Interpretation in locales only permits parameter renaming through the
  2921 locale expression.  Interpretation is smart in that interpretations
  2922 that are active already do not occur in proof obligations, neither are
  2923 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2924 inspect active interpretations of a particular locale.  For details,
  2925 see the Isar Reference manual.  Examples can be found in
  2926 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2927 
  2928 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2929 'interpret' instead.
  2930 
  2931 * New context element 'constrains' for adding type constraints to
  2932 parameters.
  2933 
  2934 * Context expressions: renaming of parameters with syntax
  2935 redeclaration.
  2936 
  2937 * Locale declaration: 'includes' disallowed.
  2938 
  2939 * Proper static binding of attribute syntax -- i.e. types / terms /
  2940 facts mentioned as arguments are always those of the locale definition
  2941 context, independently of the context of later invocations.  Moreover,
  2942 locale operations (renaming and type / term instantiation) are applied
  2943 to attribute arguments as expected.
  2944 
  2945 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2946 actual attributes; rare situations may require Attrib.attribute to
  2947 embed those attributes into Attrib.src that lack concrete syntax.
  2948 Attribute implementations need to cooperate properly with the static
  2949 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2950 Attrib.XXX_thm etc. already do the right thing without further
  2951 intervention.  Only unusual applications -- such as "where" or "of"
  2952 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2953 on the context and the facts involved -- may have to assign parsed
  2954 values to argument tokens explicitly.
  2955 
  2956 * Changed parameter management in theorem generation for long goal
  2957 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2958 theorem statement in rare situations.
  2959 
  2960 * Locale inspection command 'print_locale' omits notes elements.  Use
  2961 'print_locale!' to have them included in the output.
  2962 
  2963 
  2964 *** Provers ***
  2965 
  2966 * Provers/hypsubst.ML: improved version of the subst method, for
  2967 single-step rewriting: it now works in bound variable contexts. New is
  2968 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2969 rewrite a different subterm than the original subst method, which is
  2970 still available as 'simplesubst'.
  2971 
  2972 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2973 and quasi orders.
  2974 
  2975 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2976 reflexive-transitive closure of relations.
  2977 
  2978 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2979 limit (previously hard-coded with a value of 20) user-definable.
  2980 
  2981 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2982 is peformed already.  Object-logics merely need to finish their
  2983 initial simpset configuration as before.  INCOMPATIBILITY.
  2984 
  2985 
  2986 *** HOL ***
  2987 
  2988 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2989 
  2990   syntax (epsilon)
  2991     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2992 
  2993 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2994 and x-symbol; use option '-m epsilon' to get it actually printed.
  2995 Moreover, the mathematically important symbolic identifier \<epsilon>
  2996 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2997 
  2998 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2999 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3000 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3001 support corresponding Isar calculations.
  3002 
  3003 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3004 instead of ":".
  3005 
  3006 * theory SetInterval: changed the syntax for open intervals:
  3007 
  3008   Old       New
  3009   {..n(}    {..<n}
  3010   {)n..}    {n<..}
  3011   {m..n(}   {m..<n}
  3012   {)m..n}   {m<..n}
  3013   {)m..n(}  {m<..<n}
  3014 
  3015 The old syntax is still supported but will disappear in the next
  3016 release.  For conversion use the following Emacs search and replace
  3017 patterns (these are not perfect but work quite well):
  3018 
  3019   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3020   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3021 
  3022 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3023 equalities in commutative rings; method 'algebra' provides a generic
  3024 interface.
  3025 
  3026 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3027 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3028 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3029 be a tuple pattern.
  3030 
  3031 Some new syntax forms are available:
  3032 
  3033   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3034   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3035   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3036   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3037 
  3038 The latter form "\<Sum>x < k. e" used to be based on a separate
  3039 function "Summation", which has been discontinued.
  3040 
  3041 * theory Finite_Set: in structured induction proofs, the insert case
  3042 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3043 (insert F x)'.
  3044 
  3045 * The 'refute' command has been extended to support a much larger
  3046 fragment of HOL, including axiomatic type classes, constdefs and
  3047 typedefs, inductive datatypes and recursion.
  3048 
  3049 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3050 Requires zChaff with proof generation to be installed.  See
  3051 HOL/ex/SAT_Examples.thy for examples.
  3052 
  3053 * Datatype induction via method 'induct' now preserves the name of the
  3054 induction variable. For example, when proving P(xs::'a list) by
  3055 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3056 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3057 in unstructured proof scripts.
  3058 
  3059 * Reworked implementation of records.  Improved scalability for
  3060 records with many fields, avoiding performance problems for type
  3061 inference. Records are no longer composed of nested field types, but
  3062 of nested extension types. Therefore the record type only grows linear
  3063 in the number of extensions and not in the number of fields.  The
  3064 top-level (users) view on records is preserved.  Potential
  3065 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3066 old record representation. The type generated for a record is called
  3067 <record_name>_ext_type.
  3068 
  3069 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3070 proofs triggered by a record definition or a simproc (if
  3071 quick_and_dirty is enabled).  Definitions of large records can take
  3072 quite long.
  3073 
  3074 New simproc record_upd_simproc for simplification of multiple record
  3075 updates enabled by default.  Moreover, trivial updates are also
  3076 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3077 occasionally, since simplification is more powerful by default.
  3078 
  3079 * typedef: proper support for polymorphic sets, which contain extra
  3080 type-variables in the term.
  3081 
  3082 * Simplifier: automatically reasons about transitivity chains
  3083 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3084 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3085 old proofs break occasionally as simplification may now solve more
  3086 goals than previously.
  3087 
  3088 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3089 present.  Works for all partial orders (class "order"), in particular
  3090 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3091 just like y <= x.
  3092 
  3093 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3094 bound variable or a constant then the let is unfolded.  Otherwise
  3095 first a is simplified to b, and then f b is simplified to g. If
  3096 possible we abstract b from g arriving at "let x = b in h x",
  3097 otherwise we unfold the let and arrive at g.  The simproc can be
  3098 enabled/disabled by the reference use_let_simproc.  Potential
  3099 INCOMPATIBILITY since simplification is more powerful by default.
  3100 
  3101 * Classical reasoning: the meson method now accepts theorems as arguments.
  3102 
  3103 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3104 jobs to provide advice on the provability of subgoals.
  3105 
  3106 * Theory OrderedGroup and Ring_and_Field: various additions and
  3107 improvements to faciliate calculations involving equalities and
  3108 inequalities.
  3109 
  3110 The following theorems have been eliminated or modified
  3111 (INCOMPATIBILITY):
  3112 
  3113   abs_eq             now named abs_of_nonneg
  3114   abs_of_ge_0        now named abs_of_nonneg
  3115   abs_minus_eq       now named abs_of_nonpos
  3116   imp_abs_id         now named abs_of_nonneg
  3117   imp_abs_neg_id     now named abs_of_nonpos
  3118   mult_pos           now named mult_pos_pos
  3119   mult_pos_le        now named mult_nonneg_nonneg
  3120   mult_pos_neg_le    now named mult_nonneg_nonpos
  3121   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3122   mult_neg           now named mult_neg_neg
  3123   mult_neg_le        now named mult_nonpos_nonpos
  3124 
  3125 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3126      
  3127      zero_le_square
  3128      not_square_less_zero 
  3129 
  3130   The following lemmas have been deleted from Real/RealPow:
  3131   
  3132      realpow_zero_zero
  3133      realpow_two
  3134      realpow_less
  3135      zero_le_power
  3136      realpow_two_le
  3137      abs_realpow_two
  3138      realpow_two_abs     
  3139 
  3140 * Theory Parity: added rules for simplifying exponents.
  3141 
  3142 * Theory List:
  3143 
  3144 The following theorems have been eliminated or modified
  3145 (INCOMPATIBILITY):
  3146 
  3147   list_all_Nil       now named list_all.simps(1)
  3148   list_all_Cons      now named list_all.simps(2)
  3149   list_all_conv      now named list_all_iff
  3150   set_mem_eq         now named mem_iff
  3151 
  3152 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3153 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3154 
  3155 
  3156 *** HOL-Complex ***
  3157 
  3158 * Theory RealDef: better support for embedding natural numbers and
  3159 integers in the reals.
  3160 
  3161 The following theorems have been eliminated or modified
  3162 (INCOMPATIBILITY):
  3163 
  3164   exp_ge_add_one_self  now requires no hypotheses
  3165   real_of_int_add      reversed direction of equality (use [symmetric])
  3166   real_of_int_minus    reversed direction of equality (use [symmetric])
  3167   real_of_int_diff     reversed direction of equality (use [symmetric])
  3168   real_of_int_mult     reversed direction of equality (use [symmetric])
  3169 
  3170 * Theory RComplete: expanded support for floor and ceiling functions.
  3171 
  3172 * Theory Ln is new, with properties of the natural logarithm
  3173 
  3174 * Hyperreal: There is a new type constructor "star" for making
  3175 nonstandard types.  The old type names are now type synonyms:
  3176 
  3177   hypreal = real star
  3178   hypnat = nat star
  3179   hcomplex = complex star
  3180 
  3181 * Hyperreal: Many groups of similarly-defined constants have been
  3182 replaced by polymorphic versions (INCOMPATIBILITY):
  3183 
  3184   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3185 
  3186   starset      <-- starsetNat, starsetC
  3187   *s*          <-- *sNat*, *sc*
  3188   starset_n    <-- starsetNat_n, starsetC_n
  3189   *sn*         <-- *sNatn*, *scn*
  3190   InternalSets <-- InternalNatSets, InternalCSets
  3191 
  3192   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3193   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3194   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3195   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3196   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3197 
  3198 * Hyperreal: Many type-specific theorems have been removed in favor of
  3199 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3200 
  3201   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3202   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3203   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3204   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3205   right_minus <-- hypreal_add_minus
  3206   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3207   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3208   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3209   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3210   mult_1_right <-- hcomplex_mult_one_right
  3211   mult_zero_left <-- hcomplex_mult_zero_left
  3212   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3213   right_distrib <-- hypnat_add_mult_distrib2
  3214   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3215   right_inverse <-- hypreal_mult_inverse
  3216   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3217   order_refl <-- {hypreal,hypnat}_le_refl
  3218   order_trans <-- {hypreal,hypnat}_le_trans
  3219   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3220   order_less_le <-- {hypreal,hypnat}_less_le
  3221   linorder_linear <-- {hypreal,hypnat}_le_linear
  3222   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3223   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3224   add_nonneg_nonneg <-- hypreal_le_add_order
  3225 
  3226 * Hyperreal: Separate theorems having to do with type-specific
  3227 versions of constants have been merged into theorems that apply to the
  3228 new polymorphic constants (INCOMPATIBILITY):
  3229 
  3230   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3231   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3232   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3233   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3234   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3235   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3236   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3237   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3238   STAR_diff <-- {STAR,STARC}_diff
  3239   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3240     STARC_hcomplex_of_complex}_image_subset
  3241   starset_n_Un <-- starset{Nat,C}_n_Un
  3242   starset_n_Int <-- starset{Nat,C}_n_Int
  3243   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3244   starset_n_diff <-- starset{Nat,C}_n_diff
  3245   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3246   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3247   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3248   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3249   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3250   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3251   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3252   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3253   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3254   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3255   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3256   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3257   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3258   starfun_diff <-- starfun{C,RC,CR}_diff
  3259   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3260   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3261   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3262   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3263   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3264   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3265   starfun_Id <-- starfunC_Id
  3266   starfun_approx <-- starfun{Nat,CR}_approx
  3267   starfun_capprox <-- starfun{C,RC}_capprox
  3268   starfun_abs <-- starfunNat_rabs
  3269   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3270   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3271   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3272   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3273   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3274   starfun_add_approx <-- starfunCR_add_approx
  3275   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3276   starfun_divide <-- starfun{C,CR,RC}_divide
  3277   starfun_n <-- starfun{Nat,C}_n
  3278   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3279   starfun_n_add <-- starfun{Nat,C}_n_add
  3280   starfun_n_add_minus <-- starfunNat_n_add_minus
  3281   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3282   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3283   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3284 
  3285   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3286   star_n_minus <-- {hypreal,hcomplex}_minus
  3287   star_n_diff <-- {hypreal,hcomplex}_diff
  3288   star_n_mult <-- {hypreal,hcomplex}_mult
  3289   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3290   star_n_le <-- {hypreal,hypnat}_le
  3291   star_n_less <-- {hypreal,hypnat}_less
  3292   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3293   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3294   star_n_abs <-- hypreal_hrabs
  3295   star_n_divide <-- hcomplex_divide
  3296 
  3297   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3298   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3299   star_of_diff <-- hypreal_of_real_diff
  3300   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3301   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3302   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3303   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3304   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3305   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3306   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3307   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3308   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3309   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3310   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3311   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3312   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3313   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3314   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3315   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3316   star_of_power <-- hypreal_of_real_power
  3317   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3318 
  3319 * Hyperreal: new method "transfer" that implements the transfer
  3320 principle of nonstandard analysis. With a subgoal that mentions
  3321 nonstandard types like "'a star", the command "apply transfer"
  3322 replaces it with an equivalent one that mentions only standard types.
  3323 To be successful, all free variables must have standard types; non-
  3324 standard variables must have explicit universal quantifiers.
  3325 
  3326 * Hyperreal: A theory of Taylor series.
  3327 
  3328 
  3329 *** HOLCF ***
  3330 
  3331 * Discontinued special version of 'constdefs' (which used to support
  3332 continuous functions) in favor of the general Pure one with full
  3333 type-inference.
  3334 
  3335 * New simplification procedure for solving continuity conditions; it
  3336 is much faster on terms with many nested lambda abstractions (cubic
  3337 instead of exponential time).
  3338 
  3339 * New syntax for domain package: selector names are now optional.
  3340 Parentheses should be omitted unless argument is lazy, for example:
  3341 
  3342   domain 'a stream = cons "'a" (lazy "'a stream")
  3343 
  3344 * New command 'fixrec' for defining recursive functions with pattern
  3345 matching; defining multiple functions with mutual recursion is also
  3346 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3347 sinr, or any data constructor defined by the domain package. The given
  3348 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3349 syntax and examples.
  3350 
  3351 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3352 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3353 but the proof obligation additionally includes an admissibility
  3354 requirement. The packages generate instances of class cpo or pcpo,
  3355 with continuity and strictness theorems for Rep and Abs.
  3356 
  3357 * HOLCF: Many theorems have been renamed according to a more standard naming
  3358 scheme (INCOMPATIBILITY):
  3359 
  3360   foo_inject:  "foo$x = foo$y ==> x = y"
  3361   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3362   foo_less:    "(foo$x << foo$y) = (x << y)"
  3363   foo_strict:  "foo$UU = UU"
  3364   foo_defined: "... ==> foo$x ~= UU"
  3365   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3366 
  3367 
  3368 *** ZF ***
  3369 
  3370 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3371 including the First Isomorphism Theorem (on quotienting by the kernel
  3372 of a homomorphism).
  3373 
  3374 * ZF/Simplifier: install second copy of type solver that actually
  3375 makes use of TC rules declared to Isar proof contexts (or locales);
  3376 the old version is still required for ML proof scripts.
  3377 
  3378 
  3379 *** Cube ***
  3380 
  3381 * Converted to Isar theory format; use locales instead of axiomatic
  3382 theories.
  3383 
  3384 
  3385 *** ML ***
  3386 
  3387 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3388 for ||>, ||>>, |>>,
  3389 
  3390 * Pure/library.ML no longer defines its own option datatype, but uses
  3391 that of the SML basis, which has constructors NONE and SOME instead of
  3392 None and Some, as well as exception Option.Option instead of OPTION.
  3393 The functions the, if_none, is_some, is_none have been adapted
  3394 accordingly, while Option.map replaces apsome.
  3395 
  3396 * Pure/library.ML: the exception LIST has been given up in favour of
  3397 the standard exceptions Empty and Subscript, as well as
  3398 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3399 superceded by the standard hd and tl functions etc.
  3400 
  3401 A number of basic list functions are no longer exported to the ML
  3402 toplevel, as they are variants of predefined functions.  The following
  3403 suggests how one can translate existing code:
  3404 
  3405     rev_append xs ys = List.revAppend (xs, ys)
  3406     nth_elem (i, xs) = List.nth (xs, i)
  3407     last_elem xs = List.last xs
  3408     flat xss = List.concat xss
  3409     seq fs = List.app fs
  3410     partition P xs = List.partition P xs
  3411     mapfilter f xs = List.mapPartial f xs
  3412 
  3413 * Pure/library.ML: several combinators for linear functional
  3414 transformations, notably reverse application and composition:
  3415 
  3416   x |> f                f #> g
  3417   (x, y) |-> f          f #-> g
  3418 
  3419 * Pure/library.ML: introduced/changed precedence of infix operators:
  3420 
  3421   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3422   infix 2 ?;
  3423   infix 3 o oo ooo oooo;
  3424   infix 4 ~~ upto downto;
  3425 
  3426 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3427 infix operators.
  3428 
  3429 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3430 fold_map support linear functional transformations and nesting.  For
  3431 example:
  3432 
  3433   fold f [x1, ..., xN] y =
  3434     y |> f x1 |> ... |> f xN
  3435 
  3436   (fold o fold) f [xs1, ..., xsN] y =
  3437     y |> fold f xs1 |> ... |> fold f xsN
  3438 
  3439   fold f [x1, ..., xN] =
  3440     f x1 #> ... #> f xN
  3441 
  3442   (fold o fold) f [xs1, ..., xsN] =
  3443     fold f xs1 #> ... #> fold f xsN
  3444 
  3445 * Pure/library.ML: the following selectors on type 'a option are
  3446 available:
  3447 
  3448   the:               'a option -> 'a  (*partial*)
  3449   these:             'a option -> 'a  where 'a = 'b list
  3450   the_default: 'a -> 'a option -> 'a
  3451   the_list:          'a option -> 'a list
  3452 
  3453 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3454 basic operations for association lists, following natural argument
  3455 order; moreover the explicit equality predicate passed here avoids
  3456 potentially expensive polymorphic runtime equality checks.
  3457 The old functions may be expressed as follows:
  3458 
  3459   assoc = uncurry (AList.lookup (op =))
  3460   assocs = these oo AList.lookup (op =)
  3461   overwrite = uncurry (AList.update (op =)) o swap
  3462 
  3463 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3464 
  3465   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3466   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3467 
  3468 replacing make_keylist and keyfilter (occassionally used)
  3469 Naive rewrites:
  3470 
  3471   make_keylist = AList.make
  3472   keyfilter = AList.find (op =)
  3473 
  3474 * eq_fst and eq_snd now take explicit equality parameter, thus
  3475   avoiding eqtypes. Naive rewrites:
  3476 
  3477     eq_fst = eq_fst (op =)
  3478     eq_snd = eq_snd (op =)
  3479 
  3480 * Removed deprecated apl and apr (rarely used).
  3481   Naive rewrites:
  3482 
  3483     apl (n, op) =>>= curry op n
  3484     apr (op, m) =>>= fn n => op (n, m)
  3485 
  3486 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3487 provides a reasonably efficient light-weight implementation of sets as
  3488 lists.
  3489 
  3490 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3491 few new operations; existing lookup and update are now curried to
  3492 follow natural argument order (for use with fold etc.);
  3493 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3494 
  3495 * Pure/General: output via the Isabelle channels of
  3496 writeln/warning/error etc. is now passed through Output.output, with a
  3497 hook for arbitrary transformations depending on the print_mode
  3498 (cf. Output.add_mode -- the first active mode that provides a output
  3499 function wins).  Already formatted output may be embedded into further
  3500 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3501 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3502 accommodate easy composition of diagnostic messages etc.  Programmers
  3503 rarely need to care about Output.output or Output.raw at all, with
  3504 some notable exceptions: Output.output is required when bypassing the
  3505 standard channels (writeln etc.), or in token translations to produce
  3506 properly formatted results; Output.raw is required when capturing
  3507 already output material that will eventually be presented to the user
  3508 a second time.  For the default print mode, both Output.output and
  3509 Output.raw have no effect.
  3510 
  3511 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3512 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3513 cumulative results are displayed at the end of a batch session.
  3514 
  3515 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3516 replaced by File.platform_path and File.shell_path (with appropriate
  3517 hooks).  This provides a clean interface for unusual systems where the
  3518 internal and external process view of file names are different.
  3519 
  3520 * Pure: more efficient orders for basic syntactic entities: added
  3521 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3522 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3523 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3524 orders now -- potential INCOMPATIBILITY for code that depends on a
  3525 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3526 Library.sort_strings on result).
  3527 
  3528 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3529 fold_types traverse types/terms from left to right, observing natural
  3530 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3531 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3532 
  3533 * Pure: name spaces have been refined, with significant changes of the
  3534 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3535 to extern(_table).  The plain name entry path is superceded by a
  3536 general 'naming' context, which also includes the 'policy' to produce
  3537 a fully qualified name and external accesses of a fully qualified
  3538 name; NameSpace.extend is superceded by context dependent
  3539 Sign.declare_name.  Several theory and proof context operations modify
  3540 the naming context.  Especially note Theory.restore_naming and
  3541 ProofContext.restore_naming to get back to a sane state; note that
  3542 Theory.add_path is no longer sufficient to recover from
  3543 Theory.absolute_path in particular.
  3544 
  3545 * Pure: new flags short_names (default false) and unique_names
  3546 (default true) for controlling output of qualified names.  If
  3547 short_names is set, names are printed unqualified.  If unique_names is
  3548 reset, the name prefix is reduced to the minimum required to achieve
  3549 the original result when interning again, even if there is an overlap
  3550 with earlier declarations.
  3551 
  3552 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3553 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3554 (useful for printing error messages).  INCOMPATIBILITY.
  3555 
  3556 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3557 Theory.theory are now identified, referring to the universal
  3558 Context.theory (see Pure/context.ML).  Actual signature and theory
  3559 content is managed as theory data.  The old code and interfaces were
  3560 spread over many files and structures; the new arrangement introduces
  3561 considerable INCOMPATIBILITY to gain more clarity:
  3562 
  3563   Context -- theory management operations (name, identity, inclusion,
  3564     parents, ancestors, merge, etc.), plus generic theory data;
  3565 
  3566   Sign -- logical signature and syntax operations (declaring consts,
  3567     types, etc.), plus certify/read for common entities;
  3568 
  3569   Theory -- logical theory operations (stating axioms, definitions,
  3570     oracles), plus a copy of logical signature operations (consts,
  3571     types, etc.); also a few basic management operations (Theory.copy,
  3572     Theory.merge, etc.)
  3573 
  3574 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3575 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3576 for convenience -- they merely return the theory.
  3577 
  3578 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3579 
  3580 * Pure: the Isar proof context type is already defined early in Pure
  3581 as Context.proof (note that ProofContext.context and Proof.context are
  3582 aliases, where the latter is the preferred name).  This enables other
  3583 Isabelle components to refer to that type even before Isar is present.
  3584 
  3585 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3586 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3587 any of these kinds.  For example, Sign.intern typeK is now
  3588 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3589 Theory.hide_types.  Also note that former
  3590 Theory.hide_classes/types/consts are now
  3591 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3592 internalize their arguments!  INCOMPATIBILITY.
  3593 
  3594 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3595 datatype thmref (with constructors Name and NameSelection) instead of
  3596 plain string -- INCOMPATIBILITY;
  3597 
  3598 * Pure: cases produced by proof methods specify options, where NONE
  3599 means to remove case bindings -- INCOMPATIBILITY in
  3600 (RAW_)METHOD_CASES.
  3601 
  3602 * Pure: the following operations retrieve axioms or theorems from a
  3603 theory node or theory hierarchy, respectively:
  3604 
  3605   Theory.axioms_of: theory -> (string * term) list
  3606   Theory.all_axioms_of: theory -> (string * term) list
  3607   PureThy.thms_of: theory -> (string * thm) list
  3608   PureThy.all_thms_of: theory -> (string * thm) list
  3609 
  3610 * Pure: print_tac now outputs the goal through the trace channel.
  3611 
  3612 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3613 Reference Toplevel.debug (default false) controls detailed printing
  3614 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3615 controls execution profiling -- set to 1 for time and 2 for space
  3616 (both increase the runtime).
  3617 
  3618 * Isar session: The initial use of ROOT.ML is now always timed,
  3619 i.e. the log will show the actual process times, in contrast to the
  3620 elapsed wall-clock time that the outer shell wrapper produces.
  3621 
  3622 * Simplifier: improved handling of bound variables (nameless
  3623 representation, avoid allocating new strings).  Simprocs that invoke
  3624 the Simplifier recursively should use Simplifier.inherit_bounds to
  3625 avoid local name clashes.  Failure to do so produces warnings
  3626 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3627 for further details.
  3628 
  3629 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3630 bindings for all theorems stored within a given theory; this may help
  3631 in porting non-Isar theories to Isar ones, while keeping ML proof
  3632 scripts for the time being.
  3633 
  3634 * ML operator HTML.with_charset specifies the charset begin used for
  3635 generated HTML files.  For example:
  3636 
  3637   HTML.with_charset "utf-8" use_thy "Hebrew";
  3638   HTML.with_charset "utf-8" use_thy "Chinese";
  3639 
  3640 
  3641 *** System ***
  3642 
  3643 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3644 isabelle, isatool etc.).
  3645 
  3646 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3647 isatool doc, isatool mkdir, display_drafts etc.).
  3648 
  3649 * isatool usedir: option -f allows specification of the ML file to be
  3650 used by Isabelle; default is ROOT.ML.
  3651 
  3652 * New isatool version outputs the version identifier of the Isabelle
  3653 distribution being used.
  3654 
  3655 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3656 (containing Boolean satisfiability problems) into Isabelle/HOL
  3657 theories.
  3658 
  3659 
  3660 
  3661 New in Isabelle2004 (April 2004)
  3662 --------------------------------
  3663 
  3664 *** General ***
  3665 
  3666 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3667   Replaces linorder.ML.
  3668 
  3669 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3670   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3671   (\<a>...\<z>), are now considered normal letters, and can therefore
  3672   be used anywhere where an ASCII letter (a...zA...Z) has until
  3673   now. COMPATIBILITY: This obviously changes the parsing of some
  3674   terms, especially where a symbol has been used as a binder, say
  3675   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3676   as an identifier.  Fix it by inserting a space around former
  3677   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3678   existing theory and ML files.
  3679 
  3680 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3681 
  3682 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3683   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3684   a normal (but invisible) letter. For multiple letter subscripts repeat
  3685   \<^isub> like this: x\<^isub>1\<^isub>2.
  3686 
  3687 * Pure: There are now sub-/superscripts that can span more than one
  3688   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3689   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3690   superscript. The new control characters are not identifier parts.
  3691 
  3692 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3693   content of "..." to the latex file instead of \isacntrl... . The "..."
  3694   may consist of any printable characters excluding the end bracket >.
  3695 
  3696 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3697   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3698   declare constants "final", which prevents their being given a definition
  3699   later.  It is useful for constants whose behaviour is fixed axiomatically
  3700   rather than definitionally, such as the meta-logic connectives.
  3701 
  3702 * Pure: 'instance' now handles general arities with general sorts
  3703   (i.e. intersections of classes),
  3704 
  3705 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3706   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3707   It can be changed to alter the colors/layout of generated pages.
  3708 
  3709 
  3710 *** Isar ***
  3711 
  3712 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3713   cut_tac, subgoal_tac and thin_tac:
  3714   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3715     locales are no longer forced to write Isar proof scripts.
  3716     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3717     emulations.
  3718   - INCOMPATIBILITY: names of variables to be instantiated may no
  3719     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3720     This is consistent with the instantiation attribute "where".
  3721 
  3722 * Attributes "where" and "of":
  3723   - Now take type variables of instantiated theorem into account when reading
  3724     the instantiation string.  This fixes a bug that caused instantiated
  3725     theorems to have too special types in some circumstances.
  3726   - "where" permits explicit instantiations of type variables.
  3727 
  3728 * Calculation commands "moreover" and "also" no longer interfere with
  3729   current facts ("this"), admitting arbitrary combinations with "then"
  3730   and derived forms.
  3731 
  3732 * Locales:
  3733   - Goal statements involving the context element "includes" no longer
  3734     generate theorems with internal delta predicates (those ending on
  3735     "_axioms") in the premise.
  3736     Resolve particular premise with <locale>.intro to obtain old form.
  3737   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3738     specification and "includes" elements in goal statement.
  3739   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3740     [intro?] and [elim?] (respectively) by default.
  3741   - Experimental command for instantiation of locales in proof contexts:
  3742         instantiate <label>[<attrs>]: <loc>
  3743     Instantiates locale <loc> and adds all its theorems to the current context
  3744     taking into account their attributes.  Label and attrs are optional
  3745     modifiers, like in theorem declarations.  If present, names of
  3746     instantiated theorems are qualified with <label>, and the attributes
  3747     <attrs> are applied after any attributes these theorems might have already.
  3748       If the locale has assumptions, a chained fact of the form
  3749     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3750     are derived.  The command does not support old-style locales declared
  3751     with "locale (open)".
  3752       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3753 
  3754 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3755   (Isar) contexts.
  3756 
  3757 
  3758 *** HOL ***
  3759 
  3760 * Proof import: new image HOL4 contains the imported library from
  3761   the HOL4 system with about 2500 theorems. It is imported by
  3762   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3763   can be used like any other Isabelle image.  See
  3764   HOL/Import/HOL/README for more information.
  3765 
  3766 * Simplifier:
  3767   - Much improved handling of linear and partial orders.
  3768     Reasoners for linear and partial orders are set up for type classes
  3769     "linorder" and "order" respectively, and are added to the default simpset
  3770     as solvers.  This means that the simplifier can build transitivity chains
  3771     to solve goals from the assumptions.
  3772   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3773     of blast or auto after simplification become unnecessary because the goal
  3774     is solved by simplification already.
  3775 
  3776 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3777     all proved in axiomatic type classes for semirings, rings and fields.
  3778 
  3779 * Numerics:
  3780   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3781     now formalized using the Ring_and_Field theory mentioned above.
  3782   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3783     than before, because now they are set up once in a generic manner.
  3784   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3785     Look for the general versions in Ring_and_Field (and Power if they concern
  3786     exponentiation).
  3787 
  3788 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3789 
  3790 * Records:
  3791   - Record types are now by default printed with their type abbreviation
  3792     instead of the list of all field types. This can be configured via
  3793     the reference "print_record_type_abbr".
  3794   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3795     (not enabled by default).
  3796   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3797     EX x. x = sel r to True (not enabled by default).
  3798   - Tactic "record_split_simp_tac" to split and simplify records added.
  3799 
  3800 * 'specification' command added, allowing for definition by
  3801   specification.  There is also an 'ax_specification' command that
  3802   introduces the new constants axiomatically.
  3803 
  3804 * arith(_tac) is now able to generate counterexamples for reals as well.
  3805 
  3806 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3807 
  3808 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3809   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3810 
  3811 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3812   matrix theory to linear programming.
  3813 
  3814 * Unions and Intersections:
  3815   The latex output syntax of UN and INT has been changed
  3816   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3817   i.e. the index formulae has become a subscript.
  3818   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3819 
  3820 * Unions and Intersections over Intervals:
  3821   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3822   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3823   like in normal math, and corresponding versions for < and for intersection.
  3824 
  3825 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3826   lexicographic dictonary ordering has been added as "lexord".
  3827 
  3828 * ML: the legacy theory structures Int and List have been removed. They had
  3829   conflicted with ML Basis Library structures having the same names.
  3830 
  3831 * 'refute' command added to search for (finite) countermodels.  Only works
  3832   for a fragment of HOL.  The installation of an external SAT solver is
  3833   highly recommended.  See "HOL/Refute.thy" for details.
  3834 
  3835 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3836   formulae under an assignment of free variables to random values.
  3837   In contrast to 'refute', it can deal with inductive datatypes,
  3838   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3839   for examples.
  3840 
  3841 
  3842 *** HOLCF ***
  3843 
  3844 * Streams now come with concatenation and are part of the HOLCF image
  3845 
  3846 
  3847 
  3848 New in Isabelle2003 (May 2003)
  3849 ------------------------------
  3850 
  3851 *** General ***
  3852 
  3853 * Provers/simplifier:
  3854 
  3855   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3856     Assumptions are now subject to complete mutual simplification,
  3857     not just from left to right. The simplifier now preserves
  3858     the order of assumptions.
  3859 
  3860     Potential INCOMPATIBILITY:
  3861 
  3862     -- simp sometimes diverges where the old version did
  3863        not, e.g. invoking simp on the goal
  3864 
  3865         [| P (f x); y = x; f x = f y |] ==> Q
  3866 
  3867        now gives rise to the infinite reduction sequence
  3868 
  3869         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3870 
  3871        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3872        kind of problem.
  3873 
  3874     -- Tactics combining classical reasoner and simplification (such as auto)
  3875        are also affected by this change, because many of them rely on
  3876        simp. They may sometimes diverge as well or yield a different numbers
  3877        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3878        in case of problems. Sometimes subsequent calls to the classical
  3879        reasoner will fail because a preceeding call to the simplifier too
  3880        eagerly simplified the goal, e.g. deleted redundant premises.
  3881 
  3882   - The simplifier trace now shows the names of the applied rewrite rules
  3883 
  3884   - You can limit the number of recursive invocations of the simplifier
  3885     during conditional rewriting (where the simplifie tries to solve the
  3886     conditions before applying the rewrite rule):
  3887     ML "simp_depth_limit := n"
  3888     where n is an integer. Thus you can force termination where previously
  3889     the simplifier would diverge.
  3890 
  3891   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3892 
  3893   - No longer aborts on failed congruence proof.  Instead, the
  3894     congruence is ignored.
  3895 
  3896 * Pure: New generic framework for extracting programs from constructive
  3897   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3898   as HOL/Extraction for some case studies.
  3899 
  3900 * Pure: The main goal of the proof state is no longer shown by default, only
  3901 the subgoals. This behaviour is controlled by a new flag.
  3902    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3903 (ML: Proof.show_main_goal).
  3904 
  3905 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3906 rules whose conclusion matches subgoal 1:
  3907       PG menu: Isabelle/Isar -> Show me -> matching rules
  3908 The rules are ordered by how closely they match the subgoal.
  3909 In particular, rules that solve a subgoal outright are displayed first
  3910 (or rather last, the way they are printed).
  3911 (ML: ProofGeneral.print_intros())
  3912 
  3913 * Pure: New flag trace_unify_fail causes unification to print
  3914 diagnostic information (PG: in trace buffer) when it fails. This is
  3915 useful for figuring out why single step proofs like rule, erule or
  3916 assumption failed.
  3917 
  3918 * Pure: Locale specifications now produce predicate definitions
  3919 according to the body of text (covering assumptions modulo local
  3920 definitions); predicate "loc_axioms" covers newly introduced text,
  3921 while "loc" is cumulative wrt. all included locale expressions; the
  3922 latter view is presented only on export into the global theory
  3923 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3924 on the old view without predicates;
  3925 
  3926 * Pure: predefined locales "var" and "struct" are useful for sharing
  3927 parameters (as in CASL, for example); just specify something like
  3928 ``var x + var y + struct M'' as import;
  3929 
  3930 * Pure: improved thms_containing: proper indexing of facts instead of
  3931 raw theorems; check validity of results wrt. current name space;
  3932 include local facts of proof configuration (also covers active
  3933 locales), cover fixed variables in index; may use "_" in term
  3934 specification; an optional limit for the number of printed facts may
  3935 be given (the default is 40);
  3936 
  3937 * Pure: disallow duplicate fact bindings within new-style theory files
  3938 (batch-mode only);
  3939 
  3940 * Provers: improved induct method: assumptions introduced by case
  3941 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3942 the goal statement); "foo" still refers to all facts collectively;
  3943 
  3944 * Provers: the function blast.overloaded has been removed: all constants
  3945 are regarded as potentially overloaded, which improves robustness in exchange
  3946 for slight decrease in efficiency;
  3947 
  3948 * Provers/linorder: New generic prover for transitivity reasoning over
  3949 linear orders.  Note: this prover is not efficient!
  3950 
  3951 * Isar: preview of problems to finish 'show' now produce an error
  3952 rather than just a warning (in interactive mode);
  3953 
  3954 
  3955 *** HOL ***
  3956 
  3957 * arith(_tac)
  3958 
  3959  - Produces a counter example if it cannot prove a goal.
  3960    Note that the counter example may be spurious if the goal is not a formula
  3961    of quantifier-free linear arithmetic.
  3962    In ProofGeneral the counter example appears in the trace buffer.
  3963 
  3964  - Knows about div k and mod k where k is a numeral of type nat or int.
  3965 
  3966  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3967    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3968    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3969 
  3970 * simp's arithmetic capabilities have been enhanced a bit: it now
  3971 takes ~= in premises into account (by performing a case split);
  3972 
  3973 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3974 are distributed over a sum of terms;
  3975 
  3976 * New tactic "trans_tac" and method "trans" instantiate
  3977 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3978 "<=", "<" and "=").
  3979 
  3980 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3981 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3982 
  3983 * 'typedef' command has new option "open" to suppress the set
  3984 definition;
  3985 
  3986 * functions Min and Max on finite sets have been introduced (theory
  3987 Finite_Set);
  3988 
  3989 * attribute [symmetric] now works for relations as well; it turns
  3990 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3991 
  3992 * induct over a !!-quantified statement (say !!x1..xn):
  3993   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3994 
  3995 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3996 %x. None. Warning: empty_def now refers to the previously hidden definition
  3997 of the empty set.
  3998 
  3999 * Algebra: formalization of classical algebra.  Intended as base for
  4000 any algebraic development in Isabelle.  Currently covers group theory
  4001 (up to Sylow's theorem) and ring theory (Universal Property of
  4002 Univariate Polynomials).  Contributions welcome;
  4003 
  4004 * GroupTheory: deleted, since its material has been moved to Algebra;
  4005 
  4006 * Complex: new directory of the complex numbers with numeric constants,
  4007 nonstandard complex numbers, and some complex analysis, standard and
  4008 nonstandard (Jacques Fleuriot);
  4009 
  4010 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4011 
  4012 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4013 Fleuriot);
  4014 
  4015 * Real/HahnBanach: updated and adapted to locales;
  4016 
  4017 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4018 Gray and Kramer);
  4019 
  4020 * UNITY: added the Meier-Sanders theory of progress sets;
  4021 
  4022 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4023 as abstract algorithms, instantiated to the JVM;
  4024 
  4025 * Bali: Java source language formalization. Type system, operational
  4026 semantics, axiomatic semantics. Supported language features:
  4027 classes, interfaces, objects,virtual methods, static methods,
  4028 static/instance fields, arrays, access modifiers, definite
  4029 assignment, exceptions.
  4030 
  4031 
  4032 *** ZF ***
  4033 
  4034 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4035 universe, etc.);
  4036 
  4037 * Main ZF: virtually all theories converted to new-style format;
  4038 
  4039 
  4040 *** ML ***
  4041 
  4042 * Pure: Tactic.prove provides sane interface for internal proofs;
  4043 omits the infamous "standard" operation, so this is more appropriate
  4044 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4045 
  4046 * Pure: improved error reporting of simprocs;
  4047 
  4048 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4049 up simprocs;
  4050 
  4051 
  4052 *** Document preparation ***
  4053 
  4054 * uses \par instead of \\ for line breaks in theory text. This may
  4055 shift some page breaks in large documents. To get the old behaviour
  4056 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4057 
  4058 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4059 other packages
  4060 
  4061 * \<euro> now needs package babel/greek instead of marvosym (which
  4062 broke \Rightarrow)
  4063 
  4064 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4065 textcomp package)
  4066 
  4067 
  4068 
  4069 New in Isabelle2002 (March 2002)
  4070 --------------------------------
  4071 
  4072 *** Document preparation ***
  4073 
  4074 * greatly simplified document preparation setup, including more
  4075 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4076 instructive isatool mkdir; users should basically be able to get
  4077 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4078 users may run a separate document processing stage manually like this:
  4079 "isatool usedir -D output HOL Test && isatool document Test/output";
  4080 
  4081 * theory dependency graph may now be incorporated into documents;
  4082 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4083 with \includegraphics of LaTeX;
  4084 
  4085 * proper spacing of consecutive markup elements, especially text
  4086 blocks after section headings;
  4087 
  4088 * support bold style (for single symbols only), input syntax is like
  4089 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4090 
  4091 * \<bullet> is now output as bold \cdot by default, which looks much
  4092 better in printed text;
  4093 
  4094 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4095 note that these symbols are currently unavailable in Proof General /
  4096 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4097 
  4098 * isatool latex no longer depends on changed TEXINPUTS, instead
  4099 isatool document copies the Isabelle style files to the target
  4100 location;
  4101 
  4102 
  4103 *** Isar ***
  4104 
  4105 * Pure/Provers: improved proof by cases and induction;
  4106   - 'case' command admits impromptu naming of parameters (such as
  4107     "case (Suc n)");
  4108   - 'induct' method divinates rule instantiation from the inductive
  4109     claim; no longer requires excessive ?P bindings for proper
  4110     instantiation of cases;
  4111   - 'induct' method properly enumerates all possibilities of set/type
  4112     rules; as a consequence facts may be also passed through *type*
  4113     rules without further ado;
  4114   - 'induct' method now derives symbolic cases from the *rulified*
  4115     rule (before it used to rulify cases stemming from the internal
  4116     atomized version); this means that the context of a non-atomic
  4117     statement becomes is included in the hypothesis, avoiding the
  4118     slightly cumbersome show "PROP ?case" form;
  4119   - 'induct' may now use elim-style induction rules without chaining
  4120     facts, using ``missing'' premises from the goal state; this allows
  4121     rules stemming from inductive sets to be applied in unstructured
  4122     scripts, while still benefitting from proper handling of non-atomic
  4123     statements; NB: major inductive premises need to be put first, all
  4124     the rest of the goal is passed through the induction;
  4125   - 'induct' proper support for mutual induction involving non-atomic
  4126     rule statements (uses the new concept of simultaneous goals, see
  4127     below);
  4128   - append all possible rule selections, but only use the first
  4129     success (no backtracking);
  4130   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4131   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4132   - added 'print_induct_rules' (covered by help item in recent Proof
  4133     General versions);
  4134   - moved induct/cases attributes to Pure, methods to Provers;
  4135   - generic method setup instantiated for FOL and HOL;
  4136 
  4137 * Pure: support multiple simultaneous goal statements, for example
  4138 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4139 meta-level mechanism, this acts as if several individual goals had
  4140 been stated separately; in particular common proof methods need to be
  4141 repeated in order to cover all claims; note that a single elimination
  4142 step is *not* sufficient to establish the two conjunctions, so this
  4143 fails:
  4144 
  4145   assume "A & B" then have A and B ..   (*".." fails*)
  4146 
  4147 better use "obtain" in situations as above; alternative refer to
  4148 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4149 
  4150 * Pure: proper integration with ``locales''; unlike the original
  4151 version by Florian Kammller, Isar locales package high-level proof
  4152 contexts rather than raw logical ones (e.g. we admit to include
  4153 attributes everywhere); operations on locales include merge and
  4154 rename; support for implicit arguments (``structures''); simultaneous
  4155 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4156 some examples;
  4157 
  4158 * Pure: the following commands have been ``localized'', supporting a
  4159 target locale specification "(in name)": 'lemma', 'theorem',
  4160 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4161 stored both within the locale and at the theory level (exported and
  4162 qualified by the locale name);
  4163 
  4164 * Pure: theory goals may now be specified in ``long'' form, with
  4165 ad-hoc contexts consisting of arbitrary locale elements. for example
  4166 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4167 definitions may be given, too); the result is a meta-level rule with
  4168 the context elements being discharged in the obvious way;
  4169 
  4170 * Pure: new proof command 'using' allows to augment currently used
  4171 facts after a goal statement ('using' is syntactically analogous to
  4172 'apply', but acts on the goal's facts only); this allows chained facts
  4173 to be separated into parts given before and after a claim, as in
  4174 ``from a and b have C using d and e <proof>'';
  4175 
  4176 * Pure: renamed "antecedent" case to "rule_context";
  4177 
  4178 * Pure: new 'judgment' command records explicit information about the
  4179 object-logic embedding (used by several tools internally); no longer
  4180 use hard-wired "Trueprop";
  4181 
  4182 * Pure: added 'corollary' command;
  4183 
  4184 * Pure: fixed 'token_translation' command;
  4185 
  4186 * Pure: removed obsolete 'exported' attribute;
  4187 
  4188 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4189 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4190 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4191 
  4192 * Pure: method 'atomize' presents local goal premises as object-level
  4193 statements (atomic meta-level propositions); setup controlled via
  4194 rewrite rules declarations of 'atomize' attribute; example
  4195 application: 'induct' method with proper rule statements in improper
  4196 proof *scripts*;
  4197 
  4198 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4199 now consider the syntactic context of assumptions, giving a better
  4200 chance to get type-inference of the arguments right (this is
  4201 especially important for locales);
  4202 
  4203 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4204 mode;
  4205 
  4206 * Pure/obtain: the formal conclusion "thesis", being marked as
  4207 ``internal'', may no longer be reference directly in the text;
  4208 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4209 situations;
  4210 
  4211 * Pure: generic 'sym' attribute which declares a rule both as pure
  4212 'elim?' and for the 'symmetric' operation;
  4213 
  4214 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4215 text; the fixed correlation with particular command syntax has been
  4216 discontinued;
  4217 
  4218 * Pure: new method 'rules' is particularly well-suited for proof
  4219 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4220 but often produces more compact proof terms with less detours;
  4221 
  4222 * Pure/Provers/classical: simplified integration with pure rule
  4223 attributes and methods; the classical "intro?/elim?/dest?"
  4224 declarations coincide with the pure ones; the "rule" method no longer
  4225 includes classically swapped intros; "intro" and "elim" methods no
  4226 longer pick rules from the context; also got rid of ML declarations
  4227 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4228 INCOMPATIBILITY;
  4229 
  4230 * Provers/classical: attribute 'swapped' produces classical inversions
  4231 of introduction rules;
  4232 
  4233 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4234 rules instead of full simplifier context; 'iff' attribute handles
  4235 conditional rules;
  4236 
  4237 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4238 
  4239 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4240 "(permissive)" option to recover old behavior;
  4241 
  4242 * HOL: 'inductive' no longer features separate (collective) attributes
  4243 for 'intros' (was found too confusing);
  4244 
  4245 * HOL: properly declared induction rules less_induct and
  4246 wf_induct_rule;
  4247 
  4248 
  4249 *** HOL ***
  4250 
  4251 * HOL: moved over to sane numeral syntax; the new policy is as
  4252 follows:
  4253 
  4254   - 0 and 1 are polymorphic constants, which are defined on any
  4255   numeric type (nat, int, real etc.);
  4256 
  4257   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4258   binary representation internally;
  4259 
  4260   - type nat has special constructor Suc, and generally prefers Suc 0
  4261   over 1::nat and Suc (Suc 0) over 2::nat;
  4262 
  4263 This change may cause significant problems of INCOMPATIBILITY; here
  4264 are some hints on converting existing sources:
  4265 
  4266   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4267   entities, so expressions involving "-" (unary or binary minus) need
  4268   to be spaced properly;
  4269 
  4270   - existing occurrences of "1" may need to be constraint "1::nat" or
  4271   even replaced by Suc 0; similar for old "2";
  4272 
  4273   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4274 
  4275   - remove all special provisions on numerals in proofs;
  4276 
  4277 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4278 representation (depends on bin_arith_simps in the default context);
  4279 
  4280 * HOL: symbolic syntax for x^2 (numeral 2);
  4281 
  4282 * HOL: the class of all HOL types is now called "type" rather than
  4283 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4284 in axclass/classes, instance/arities, and (usually rare) occurrences
  4285 in typings (of consts etc.); internally the class is called
  4286 "HOL.type", ML programs should refer to HOLogic.typeS;
  4287 
  4288 * HOL/record package improvements:
  4289   - new derived operations "fields" to build a partial record section,
  4290     "extend" to promote a fixed record to a record scheme, and
  4291     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4292     declared as simp by default;
  4293   - shared operations ("more", "fields", etc.) now need to be always
  4294     qualified) --- potential INCOMPATIBILITY;
  4295   - removed "make_scheme" operations (use "make" with "extend") --
  4296     INCOMPATIBILITY;
  4297   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4298   - provides cases/induct rules for use with corresponding Isar
  4299     methods (for concrete records, record schemes, concrete more
  4300     parts, and schematic more parts -- in that order);
  4301   - internal definitions directly based on a light-weight abstract
  4302     theory of product types over typedef rather than datatype;
  4303 
  4304 * HOL: generic code generator for generating executable ML code from
  4305 specifications; specific support for HOL constructs such as inductive
  4306 datatypes and sets, as well as recursive functions; can be invoked
  4307 via 'generate_code' theory section;
  4308 
  4309 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4310 
  4311 * HOL: consolidated and renamed several theories.  In particular:
  4312         Ord.thy has been absorbed into HOL.thy
  4313         String.thy has been absorbed into List.thy
  4314 
  4315 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4316 (beware of argument permutation!);
  4317 
  4318 * HOL: linorder_less_split superseded by linorder_cases;
  4319 
  4320 * HOL/List: "nodups" renamed to "distinct";
  4321 
  4322 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4323 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4324   - Ex_def has changed, now need to use some_eq_ex
  4325 
  4326 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4327 in this (rare) case use:
  4328 
  4329   delSWrapper "split_all_tac"
  4330   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4331 
  4332 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4333 MAY FAIL;
  4334 
  4335 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4336 Isabelle's type classes, ^ on functions and relations has too general
  4337 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4338 necessary to attach explicit type constraints;
  4339 
  4340 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4341 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4342 renamed accordingly (eg "compI" -> "rel_compI").
  4343 
  4344 * HOL: syntax translations now work properly with numerals and records
  4345 expressions;
  4346 
  4347 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4348 of "lam" -- INCOMPATIBILITY;
  4349 
  4350 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4351 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4352 renamed "Product_Type.unit";
  4353 
  4354 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4355 
  4356 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4357 the "cases" method);
  4358 
  4359 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4360 Florian Kammller);
  4361 
  4362 * HOL/IMP: updated and converted to new-style theory format; several
  4363 parts turned into readable document, with proper Isar proof texts and
  4364 some explanations (by Gerwin Klein);
  4365 
  4366 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4367 
  4368 * HOL-Hyperreal is now a logic image;
  4369 
  4370 
  4371 *** HOLCF ***
  4372 
  4373 * Isar: consts/constdefs supports mixfix syntax for continuous
  4374 operations;
  4375 
  4376 * Isar: domain package adapted to new-style theory format, e.g. see
  4377 HOLCF/ex/Dnat.thy;
  4378 
  4379 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4380 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4381 lift.induct_tac, always use UU instead of Undef;
  4382 
  4383 * HOLCF/IMP: updated and converted to new-style theory;
  4384 
  4385 
  4386 *** ZF ***
  4387 
  4388 * Isar: proper integration of logic-specific tools and packages,
  4389 including theory commands '(co)inductive', '(co)datatype',
  4390 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4391 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4392 
  4393 * theory Main no longer includes AC; for the Axiom of Choice, base
  4394 your theory on Main_ZFC;
  4395 
  4396 * the integer library now covers quotients and remainders, with many
  4397 laws relating division to addition, multiplication, etc.;
  4398 
  4399 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4400 typeless version of the formalism;
  4401 
  4402 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4403 format;
  4404 
  4405 * ZF/Induct: new directory for examples of inductive definitions,
  4406 including theory Multiset for multiset orderings; converted to
  4407 new-style theory format;
  4408 
  4409 * ZF: many new theorems about lists, ordinals, etc.;
  4410 
  4411 
  4412 *** General ***
  4413 
  4414 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4415 variable proof controls level of detail: 0 = no proofs (only oracle
  4416 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4417 also ref manual for further ML interfaces;
  4418 
  4419 * Pure/axclass: removed obsolete ML interface
  4420 goal_subclass/goal_arity;
  4421 
  4422 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4423 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4424 separate tokens, so expressions involving minus need to be spaced
  4425 properly;
  4426 
  4427 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4428 rather than "infixl" or "infixr";
  4429 
  4430 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4431 sort constraint specifications in type inference; e.g. "x::_::foo"
  4432 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4433 type variable);
  4434 
  4435 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4436 control output of nested => (types); the default behavior is
  4437 "type_brackets";
  4438 
  4439 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4440 tokens into AST constants;
  4441 
  4442 * Pure/syntax: prefer later declarations of translations and print
  4443 translation functions; potential INCOMPATIBILITY: need to reverse
  4444 multiple declarations for same syntax element constant;
  4445 
  4446 * Pure/show_hyps reset by default (in accordance to existing Isar
  4447 practice);
  4448 
  4449 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4450 addSafter;
  4451 
  4452 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4453 as well;
  4454 
  4455 * system: tested support for MacOS X; should be able to get Isabelle +
  4456 Proof General to work in a plain Terminal after installing Poly/ML
  4457 (e.g. from the Isabelle distribution area) and GNU bash alone
  4458 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4459 support requires further installations, e.g. from
  4460 http://fink.sourceforge.net/);
  4461 
  4462 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4463 
  4464 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4465 of 40 MB), cf. ML_OPTIONS;
  4466 
  4467 * system: Proof General keywords specification is now part of the
  4468 Isabelle distribution (see etc/isar-keywords.el);
  4469 
  4470 * system: support for persistent Proof General sessions (refrain from
  4471 outdating all loaded theories on startup); user may create writable
  4472 logic images like this: ``isabelle -q HOL Test'';
  4473 
  4474 * system: smart selection of Isabelle process versus Isabelle
  4475 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4476 run both "isabelle" and "Isabelle" even if file names are badly
  4477 damaged (executable inspects the case of the first letter of its own
  4478 name); added separate "isabelle-process" and "isabelle-interface";
  4479 
  4480 * system: refrain from any attempt at filtering input streams; no
  4481 longer support ``8bit'' encoding of old isabelle font, instead proper
  4482 iso-latin characters may now be used; the related isatools
  4483 "symbolinput" and "nonascii" have disappeared as well;
  4484 
  4485 * system: removed old "xterm" interface (the print modes "xterm" and
  4486 "xterm_color" are still available for direct use in a suitable
  4487 terminal);
  4488 
  4489 
  4490 
  4491 New in Isabelle99-2 (February 2001)
  4492 -----------------------------------
  4493 
  4494 *** Overview of INCOMPATIBILITIES ***
  4495 
  4496 * HOL: please note that theories in the Library and elsewhere often use the
  4497 new-style (Isar) format; to refer to their theorems in an ML script you must
  4498 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4499 
  4500 * HOL: inductive package no longer splits induction rule aggressively,
  4501 but only as far as specified by the introductions given; the old
  4502 format may be recovered via ML function complete_split_rule or attribute
  4503 'split_rule (complete)';
  4504 
  4505 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4506 gfp_Tarski to gfp_unfold;
  4507 
  4508 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4509 
  4510 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4511 relation); infix "^^" has been renamed "``"; infix "``" has been
  4512 renamed "`"; "univalent" has been renamed "single_valued";
  4513 
  4514 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4515 operation;
  4516 
  4517 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4518 
  4519 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4520 
  4521 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4522 consequence, it is no longer monotonic wrt. the local goal context
  4523 (which is now passed through the inductive cases);
  4524 
  4525 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4526 \<gg> to \<ggreater>;
  4527 
  4528 
  4529 *** Document preparation ***
  4530 
  4531 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4532 available: are "it" for near math-mode best-style output, "sl" for
  4533 slanted text style, and "tt" for plain type-writer; if no
  4534 \isabellestyle command is given, output is according to slanted
  4535 type-writer);
  4536 
  4537 * support sub/super scripts (for single symbols only), input syntax is
  4538 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4539 
  4540 * some more standard symbols; see Appendix A of the system manual for
  4541 the complete list of symbols defined in isabellesym.sty;
  4542 
  4543 * improved isabelle style files; more abstract symbol implementation
  4544 (should now use \isamath{...} and \isatext{...} in custom symbol
  4545 definitions);
  4546 
  4547 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4548 state; Note that presentation of goal states does not conform to
  4549 actual human-readable proof documents.  Please do not include goal
  4550 states into document output unless you really know what you are doing!
  4551 
  4552 * proper indentation of antiquoted output with proportional LaTeX
  4553 fonts;
  4554 
  4555 * no_document ML operator temporarily disables LaTeX document
  4556 generation;
  4557 
  4558 * isatool unsymbolize tunes sources for plain ASCII communication;
  4559 
  4560 
  4561 *** Isar ***
  4562 
  4563 * Pure: Isar now suffers initial goal statements to contain unbound
  4564 schematic variables (this does not conform to actual readable proof
  4565 documents, due to unpredictable outcome and non-compositional proof
  4566 checking); users who know what they are doing may use schematic goals
  4567 for Prolog-style synthesis of proven results;
  4568 
  4569 * Pure: assumption method (an implicit finishing) now handles actual
  4570 rules as well;
  4571 
  4572 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4573 initial goal, declare "that" only as Pure intro (only for single
  4574 steps); the "that" rule assumption may now be involved in implicit
  4575 finishing, thus ".." becomes a feasible for trivial obtains;
  4576 
  4577 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4578 instance proofs may be performed by "..";
  4579 
  4580 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4581 statements as well;
  4582 
  4583 * Pure: more robust selection of calculational rules;
  4584 
  4585 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4586 rule (as well as the assumption rule);
  4587 
  4588 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4589 lemmas, using the graph browser tool;
  4590 
  4591 * Pure: predict failure of "show" in interactive mode;
  4592 
  4593 * Pure: 'thms_containing' now takes actual terms as arguments;
  4594 
  4595 * HOL: improved method 'induct' --- now handles non-atomic goals
  4596 (potential INCOMPATIBILITY); tuned error handling;
  4597 
  4598 * HOL: cases and induct rules now provide explicit hints about the
  4599 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4600 any remaining facts are inserted into the goal verbatim;
  4601 
  4602 * HOL: local contexts (aka cases) may now contain term bindings as
  4603 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4604 the result to be shown in each case;
  4605 
  4606 * HOL: added 'recdef_tc' command;
  4607 
  4608 * isatool convert assists in eliminating legacy ML scripts;
  4609 
  4610 
  4611 *** HOL ***
  4612 
  4613 * HOL/Library: a collection of generic theories to be used together
  4614 with main HOL; the theory loader path already includes this directory
  4615 by default; the following existing theories have been moved here:
  4616 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4617 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4618 
  4619 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4620 modelling and verification task performed in Isabelle/HOL +
  4621 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4622 
  4623 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4624 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4625 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4626 'domain', this makes the theory consistent with mathematical
  4627 literature;
  4628 
  4629 * HOL basics: added overloaded operations "inverse" and "divide"
  4630 (infix "/"), syntax for generic "abs" operation, generic summation
  4631 operator \<Sum>;
  4632 
  4633 * HOL/typedef: simplified package, provide more useful rules (see also
  4634 HOL/subset.thy);
  4635 
  4636 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4637 now expressed as a proper nested rule (old-style tactic scripts may
  4638 require atomize_strip_tac to cope with non-atomic premises);
  4639 
  4640 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4641 to "split_conv" (old name still available for compatibility);
  4642 
  4643 * HOL: improved concrete syntax for strings (e.g. allows translation
  4644 rules with string literals);
  4645 
  4646 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4647  and Fleuriot's mechanization of analysis, including the transcendental
  4648  functions for the reals;
  4649 
  4650 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4651 
  4652 
  4653 *** CTT ***
  4654 
  4655 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4656 "lam" is displayed as TWO lambda-symbols
  4657 
  4658 * CTT: theory Main now available, containing everything (that is, Bool
  4659 and Arith);
  4660 
  4661 
  4662 *** General ***
  4663 
  4664 * Pure: the Simplifier has been implemented properly as a derived rule
  4665 outside of the actual kernel (at last!); the overall performance
  4666 penalty in practical applications is about 50%, while reliability of
  4667 the Isabelle inference kernel has been greatly improved;
  4668 
  4669 * print modes "brackets" and "no_brackets" control output of nested =>
  4670 (types) and ==> (props); the default behaviour is "brackets";
  4671 
  4672 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4673 as assumptions as well;
  4674 
  4675 * system: support Poly/ML 4.0;
  4676 
  4677 * system: isatool install handles KDE version 1 or 2;
  4678 
  4679 
  4680 
  4681 New in Isabelle99-1 (October 2000)
  4682 ----------------------------------
  4683 
  4684 *** Overview of INCOMPATIBILITIES ***
  4685 
  4686 * HOL: simplification of natural numbers is much changed; to partly
  4687 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4688 issue the following ML commands:
  4689 
  4690   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4691   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4692 
  4693 * HOL: simplification no longer dives into case-expressions; this is
  4694 controlled by "t.weak_case_cong" for each datatype t;
  4695 
  4696 * HOL: nat_less_induct renamed to less_induct;
  4697 
  4698 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4699 fixsome to patch .thy and .ML sources automatically;
  4700 
  4701   select_equality  -> some_equality
  4702   select_eq_Ex     -> some_eq_ex
  4703   selectI2EX       -> someI2_ex
  4704   selectI2         -> someI2
  4705   selectI          -> someI
  4706   select1_equality -> some1_equality
  4707   Eps_sym_eq       -> some_sym_eq_trivial
  4708   Eps_eq           -> some_eq_trivial
  4709 
  4710 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4711 
  4712 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4713 instead);
  4714 
  4715 * HOL: the recursion equations generated by 'recdef' are now called
  4716 f.simps instead of f.rules;
  4717 
  4718 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4719 
  4720 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4721 sometimes be needed;
  4722 
  4723 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4724 
  4725 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4726 
  4727 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4728 product is now "<*>" instead of "Times"; the lexicographic product is
  4729 now "<*lex*>" instead of "**";
  4730 
  4731 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4732 of main HOL, but was unused); better use HOL's datatype package;
  4733 
  4734 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4735 the old syntax may be recovered as follows:
  4736 
  4737   syntax (symbols)
  4738     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4739       (infixl "\\<oplus>" 100)
  4740 
  4741 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4742 
  4743 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4744 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4745 internally;
  4746 
  4747 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4748 changed from A/r to A//r;
  4749 
  4750 * ZF: new treatment of arithmetic (nat & int) may break some old
  4751 proofs;
  4752 
  4753 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4754 rulify -> rule_format, elimify -> elim_format, ...);
  4755 
  4756 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4757 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4758 should have to change intro!! to intro? only); replaced "delrule" by
  4759 "rule del";
  4760 
  4761 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4762 
  4763 * Provers: strengthened force_tac by using new first_best_tac;
  4764 
  4765 * LaTeX document preparation: several changes of isabelle.sty (see
  4766 lib/texinputs);
  4767 
  4768 
  4769 *** Document preparation ***
  4770 
  4771 * formal comments (text blocks etc.) in new-style theories may now
  4772 contain antiquotations of thm/prop/term/typ/text to be presented
  4773 according to latex print mode; concrete syntax is like this:
  4774 @{term[show_types] "f(x) = a + x"};
  4775 
  4776 * isatool mkdir provides easy setup of Isabelle session directories,
  4777 including proper document sources;
  4778 
  4779 * generated LaTeX sources are now deleted after successful run
  4780 (isatool document -c); may retain a copy somewhere else via -D option
  4781 of isatool usedir;
  4782 
  4783 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4784 style files, achieving self-contained LaTeX sources and simplifying
  4785 LaTeX debugging;
  4786 
  4787 * old-style theories now produce (crude) LaTeX output as well;
  4788 
  4789 * browser info session directories are now self-contained (may be put
  4790 on WWW server seperately); improved graphs of nested sessions; removed
  4791 graph for 'all sessions';
  4792 
  4793 * several improvements in isabelle style files; \isabellestyle{it}
  4794 produces fake math mode output; \isamarkupheader is now \section by
  4795 default; see lib/texinputs/isabelle.sty etc.;
  4796 
  4797 
  4798 *** Isar ***
  4799 
  4800 * Isar/Pure: local results and corresponding term bindings are now
  4801 subject to Hindley-Milner polymorphism (similar to ML); this
  4802 accommodates incremental type-inference very nicely;
  4803 
  4804 * Isar/Pure: new derived language element 'obtain' supports
  4805 generalized existence reasoning;
  4806 
  4807 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4808 support accumulation of results, without applying any rules yet;
  4809 useful to collect intermediate results without explicit name
  4810 references, and for use with transitivity rules with more than 2
  4811 premises;
  4812 
  4813 * Isar/Pure: scalable support for case-analysis type proofs: new
  4814 'case' language element refers to local contexts symbolically, as
  4815 produced by certain proof methods; internally, case names are attached
  4816 to theorems as "tags";
  4817 
  4818 * Isar/Pure: theory command 'hide' removes declarations from
  4819 class/type/const name spaces;
  4820 
  4821 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4822 indicate potential overloading;
  4823 
  4824 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4825 
  4826 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4827 "{a,b,c}" instead of {a,b,c};
  4828 
  4829 * Isar/Pure now provides its own version of intro/elim/dest
  4830 attributes; useful for building new logics, but beware of confusion
  4831 with the version in Provers/classical;
  4832 
  4833 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4834 case name 'antecedent';
  4835 
  4836 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4837 to the current context is now done automatically);
  4838 
  4839 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4840 for definining proof methods in ML;
  4841 
  4842 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4843 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4844 most cases, one should have to change intro!! to intro? only);
  4845 replaced "delrule" by "rule del";
  4846 
  4847 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4848 'symmetric' attribute (the latter supercedes [RS sym]);
  4849 
  4850 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4851 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4852 well (including splits);
  4853 
  4854 * Isar/Provers: Simplifier and Classical methods now support all kind
  4855 of modifiers used in the past, including 'cong', 'iff', etc.
  4856 
  4857 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4858 of Simplifier and Classical reasoner);
  4859 
  4860 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4861 now support named cases; major packages (inductive, datatype, primrec,
  4862 recdef) support case names and properly name parameters;
  4863 
  4864 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4865 monotonicity conditions are extracted to be proven at end of
  4866 calculations;
  4867 
  4868 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4869 method anyway;
  4870 
  4871 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4872 split_if split_if_asm; datatype package provides theorems foo.splits =
  4873 foo.split foo.split_asm for each datatype;
  4874 
  4875 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4876 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4877 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4878 use "(cases (simplified))" method in proper proof texts);
  4879 
  4880 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4881 
  4882 * Isar: names of theorems etc. may be natural numbers as well;
  4883 
  4884 * Isar: 'pr' command: optional arguments for goals_limit and
  4885 ProofContext.prems_limit; no longer prints theory contexts, but only
  4886 proof states;
  4887 
  4888 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4889 additional print modes to be specified; e.g. "pr(latex)" will print
  4890 proof state according to the Isabelle LaTeX style;
  4891 
  4892 * Isar: improved support for emulating tactic scripts, including proof
  4893 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4894 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4895 (for HOL datatypes);
  4896 
  4897 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4898 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4899 'proof method scripts' have to be in depth-first order;
  4900 
  4901 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4902 
  4903 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4904 should instead use individual commands for printing items
  4905 (print_commands, print_methods etc.);
  4906 
  4907 * Isar: added 'nothing' --- the empty list of theorems;
  4908 
  4909 
  4910 *** HOL ***
  4911 
  4912 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4913 corresponding virtual machine and a specification of its bytecode
  4914 verifier and a lightweight bytecode verifier, including proofs of
  4915 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4916 Cornelia Pusch (see also the homepage of project Bali at
  4917 http://isabelle.in.tum.de/Bali/);
  4918 
  4919 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4920 Clemens Ballarin;
  4921 
  4922 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4923 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4924 Rasmussen;
  4925 
  4926 * HOL/Lattice: fundamental concepts of lattice theory and order
  4927 structures, including duals, properties of bounds versus algebraic
  4928 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4929 Theorem for complete lattices etc.; may also serve as a demonstration
  4930 for abstract algebraic reasoning using axiomatic type classes, and
  4931 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4932 
  4933 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4934 von Oheimb;
  4935 
  4936 * HOL/IMPP: extension of IMP with local variables and mutually
  4937 recursive procedures, by David von Oheimb;
  4938 
  4939 * HOL/Lambda: converted into new-style theory and document;
  4940 
  4941 * HOL/ex/Multiquote: example of multiple nested quotations and
  4942 anti-quotations -- basically a generalized version of de-Bruijn
  4943 representation; very useful in avoiding lifting of operations;
  4944 
  4945 * HOL/record: added general record equality rule to simpset; fixed
  4946 select-update simplification procedure to handle extended records as
  4947 well; admit "r" as field name;
  4948 
  4949 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4950 other numeric types and also as the identity of groups, rings, etc.;
  4951 
  4952 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4953 Types nat and int belong to this axclass;
  4954 
  4955 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4956    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4957    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4958   two terms #m*u and #n*u are replaced by #(m+n)*u
  4959     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4960   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4961     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4962 
  4963 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4964 powerful prover for predicate logic but knows nothing of clasets; see
  4965 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4966 
  4967 * HOL: new version of "case_tac" subsumes both boolean case split and
  4968 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4969 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4970 
  4971 * HOL: simplification no longer dives into case-expressions: only the
  4972 selector expression is simplified, but not the remaining arms; to
  4973 enable full simplification of case-expressions for datatype t, you may
  4974 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4975 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4976 
  4977 * HOL/recdef: the recursion equations generated by 'recdef' for
  4978 function 'f' are now called f.simps instead of f.rules; if all
  4979 termination conditions are proved automatically, these simplification
  4980 rules are added to the simpset, as in primrec; rules may be named
  4981 individually as well, resulting in a separate list of theorems for
  4982 each equation;
  4983 
  4984 * HOL/While is a new theory that provides a while-combinator. It
  4985 permits the definition of tail-recursive functions without the
  4986 provision of a termination measure. The latter is necessary once the
  4987 invariant proof rule for while is applied.
  4988 
  4989 * HOL: new (overloaded) notation for the set of elements below/above
  4990 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4991 
  4992 * HOL: theorems impI, allI, ballI bound as "strip";
  4993 
  4994 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4995 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4996 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4997 
  4998 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4999 
  5000 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5001 main HOL, but was unused);
  5002 
  5003 * HOL: fewer consts declared as global (e.g. have to refer to
  5004 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5005 
  5006 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5007 in case of overlap with user translations (e.g. judgements over
  5008 tuples); (note that the underlying logical represenation is still
  5009 bogus);
  5010 
  5011 
  5012 *** ZF ***
  5013 
  5014 * ZF: simplification automatically cancels common terms in arithmetic
  5015 expressions over nat and int;
  5016 
  5017 * ZF: new treatment of nat to minimize type-checking: all operators
  5018 coerce their operands to a natural number using the function natify,
  5019 making the algebraic laws unconditional;
  5020 
  5021 * ZF: as above, for int: operators coerce their operands to an integer
  5022 using the function intify;
  5023 
  5024 * ZF: the integer library now contains many of the usual laws for the
  5025 orderings, including $<=, and monotonicity laws for $+ and $*;
  5026 
  5027 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5028 simplification;
  5029 
  5030 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5031 to the simplifier and classical reasoner simultaneously;
  5032 
  5033 
  5034 *** General ***
  5035 
  5036 * Provers: blast_tac now handles actual object-logic rules as
  5037 assumptions; note that auto_tac uses blast_tac internally as well;
  5038 
  5039 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5040 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5041 
  5042 * Provers: delrules now handles destruct rules as well (no longer need
  5043 explicit make_elim);
  5044 
  5045 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5046   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5047 use instead the strong form,
  5048   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5049 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5050 from destruct-rules;
  5051 
  5052 * Provers: Simplifier.easy_setup provides a fast path to basic
  5053 Simplifier setup for new object-logics;
  5054 
  5055 * Pure: AST translation rules no longer require constant head on LHS;
  5056 
  5057 * Pure: improved name spaces: ambiguous output is qualified; support
  5058 for hiding of names;
  5059 
  5060 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5061 XSYMBOL_HOME; no longer need to do manual configuration in most
  5062 situations;
  5063 
  5064 * system: compression of ML heaps images may now be controlled via -c
  5065 option of isabelle and isatool usedir (currently only observed by
  5066 Poly/ML);
  5067 
  5068 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5069 useful for remote X11);
  5070 
  5071 * system: provide TAGS file for Isabelle sources;
  5072 
  5073 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5074 order;
  5075 
  5076 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5077 timing flag supersedes proof_timing and Toplevel.trace;
  5078 
  5079 * ML: new combinators |>> and |>>> for incremental transformations
  5080 with secondary results (e.g. certain theory extensions):
  5081 
  5082 * ML: PureThy.add_defs gets additional argument to indicate potential
  5083 overloading (usually false);
  5084 
  5085 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5086 results;
  5087 
  5088 
  5089 
  5090 New in Isabelle99 (October 1999)
  5091 --------------------------------
  5092 
  5093 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5094 
  5095 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5096 are no longer simplified.  (This allows the simplifier to unfold recursive
  5097 functional programs.)  To restore the old behaviour, declare
  5098 
  5099     Delcongs [if_weak_cong];
  5100 
  5101 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5102 complement;
  5103 
  5104 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5105 
  5106 * HOL/datatype: mutual_induct_tac no longer exists --
  5107   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5108 
  5109 * HOL/typedef: fixed type inference for representing set; type
  5110 arguments now have to occur explicitly on the rhs as type constraints;
  5111 
  5112 * ZF: The con_defs part of an inductive definition may no longer refer
  5113 to constants declared in the same theory;
  5114 
  5115 * HOL, ZF: the function mk_cases, generated by the inductive
  5116 definition package, has lost an argument.  To simplify its result, it
  5117 uses the default simpset instead of a supplied list of theorems.
  5118 
  5119 * HOL/List: the constructors of type list are now Nil and Cons;
  5120 
  5121 * Simplifier: the type of the infix ML functions
  5122         setSSolver addSSolver setSolver addSolver
  5123 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5124 for packaging solvers. A solver is created via
  5125         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5126 where the string argument is only a comment.
  5127 
  5128 
  5129 *** Proof tools ***
  5130 
  5131 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5132 decision procedure for linear arithmetic. Currently it is used for
  5133 types `nat', `int', and `real' in HOL (see below); it can, should and
  5134 will be instantiated for other types and logics as well.
  5135 
  5136 * The simplifier now accepts rewrite rules with flexible heads, eg
  5137      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5138   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5139   matching.
  5140 
  5141 
  5142 *** General ***
  5143 
  5144 * New Isabelle/Isar subsystem provides an alternative to traditional
  5145 tactical theorem proving; together with the ProofGeneral/isar user
  5146 interface it offers an interactive environment for developing human
  5147 readable proof documents (Isar == Intelligible semi-automated
  5148 reasoning); for further information see isatool doc isar-ref,
  5149 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5150 
  5151 * improved and simplified presentation of theories: better HTML markup
  5152 (including colors), graph views in several sizes; isatool usedir now
  5153 provides a proper interface for user theories (via -P option); actual
  5154 document preparation based on (PDF)LaTeX is available as well (for
  5155 new-style theories only); see isatool doc system for more information;
  5156 
  5157 * native support for Proof General, both for classic Isabelle and
  5158 Isabelle/Isar;
  5159 
  5160 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5161 using the graph browser tool;
  5162 
  5163 * Isabelle manuals now also available as PDF;
  5164 
  5165 * theory loader rewritten from scratch (may not be fully
  5166 bug-compatible); old loadpath variable has been replaced by show_path,
  5167 add_path, del_path, reset_path functions; new operations such as
  5168 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5169 isatool doc ref);
  5170 
  5171 * improved isatool install: option -k creates KDE application icon,
  5172 option -p DIR installs standalone binaries;
  5173 
  5174 * added ML_PLATFORM setting (useful for cross-platform installations);
  5175 more robust handling of platform specific ML images for SML/NJ;
  5176 
  5177 * the settings environment is now statically scoped, i.e. it is never
  5178 created again in sub-processes invoked from isabelle, isatool, or
  5179 Isabelle;
  5180 
  5181 * path element specification '~~' refers to '$ISABELLE_HOME';
  5182 
  5183 * in locales, the "assumes" and "defines" parts may be omitted if
  5184 empty;
  5185 
  5186 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5187 long arrows);
  5188 
  5189 * new print_mode "HTML";
  5190 
  5191 * new flag show_tags controls display of tags of theorems (which are
  5192 basically just comments that may be attached by some tools);
  5193 
  5194 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5195 mode and goal output format:
  5196 
  5197 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5198 244c244
  5199 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5200 ---
  5201 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5202 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5203 181c181
  5204 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5205 ---
  5206 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5207 
  5208 * function bind_thms stores lists of theorems (cf. bind_thm);
  5209 
  5210 * new shorthand tactics ftac, eatac, datac, fatac;
  5211 
  5212 * qed (and friends) now accept "" as result name; in that case the
  5213 theorem is not stored, but proper checks and presentation of the
  5214 result still apply;
  5215 
  5216 * theorem database now also indexes constants "Trueprop", "all",
  5217 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5218 
  5219 
  5220 *** HOL ***
  5221 
  5222 ** HOL arithmetic **
  5223 
  5224 * There are now decision procedures for linear arithmetic over nat and
  5225 int:
  5226 
  5227 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5228 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5229 are treated as atomic; subformulae not involving type `nat' or `int'
  5230 are ignored; quantified subformulae are ignored unless they are
  5231 positive universal or negative existential. The tactic has to be
  5232 invoked by hand and can be a little bit slow. In particular, the
  5233 running time is exponential in the number of occurrences of `min' and
  5234 `max', and `-' on `nat'.
  5235 
  5236 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5237 (negated) (in)equalities among the premises and the conclusion into
  5238 account (i.e. no compound formulae) and does not know about `min' and
  5239 `max', and `-' on `nat'. It is fast and is used automatically by the
  5240 simplifier.
  5241 
  5242 NB: At the moment, these decision procedures do not cope with mixed
  5243 nat/int formulae where the two parts interact, such as `m < n ==>
  5244 int(m) < int(n)'.
  5245 
  5246 * HOL/Numeral provides a generic theory of numerals (encoded
  5247 efficiently as bit strings); setup for types nat/int/real is in place;
  5248 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5249 int, existing theories and proof scripts may require a few additional
  5250 type constraints;
  5251 
  5252 * integer division and remainder can now be performed on constant
  5253 arguments;
  5254 
  5255 * many properties of integer multiplication, division and remainder
  5256 are now available;
  5257 
  5258 * An interface to the Stanford Validity Checker (SVC) is available through the
  5259 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5260 are proved automatically.  SVC must be installed separately, and its results
  5261 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5262 invocation of the underlying oracle).  For SVC see
  5263   http://verify.stanford.edu/SVC
  5264 
  5265 * IsaMakefile: the HOL-Real target now builds an actual image;
  5266 
  5267 
  5268 ** HOL misc **
  5269 
  5270 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5271 (in Isabelle/Isar) -- by Gertrud Bauer;
  5272 
  5273 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5274 analysis for assembly languages with subtypes;
  5275 
  5276 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5277 -- avoids syntactic ambiguities and treats state, transition, and
  5278 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5279 changed syntax and (many) tactics;
  5280 
  5281 * HOL/inductive: Now also handles more general introduction rules such
  5282   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5283   theorems are now maintained within the theory (maintained via the
  5284   "mono" attribute);
  5285 
  5286 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5287   (using function types) such as
  5288 
  5289   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5290 
  5291 * HOL/record: record_simproc (part of the default simpset) takes care
  5292 of selectors applied to updated records; record_split_tac is no longer
  5293 part of the default claset; update_defs may now be removed from the
  5294 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5295 
  5296   claset_ref () := claset() addSWrapper record_split_wrapper;
  5297   Delsimprocs [record_simproc]
  5298 
  5299 * HOL/typedef: fixed type inference for representing set; type
  5300 arguments now have to occur explicitly on the rhs as type constraints;
  5301 
  5302 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5303 names rather than an ML expression;
  5304 
  5305 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5306 supplied later.  Program schemes can be defined, such as
  5307     "While B C s = (if B s then While B C (C s) else s)"
  5308 where the well-founded relation can be chosen after B and C have been given.
  5309 
  5310 * HOL/List: the constructors of type list are now Nil and Cons;
  5311 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5312 course, ML tools referring to List.list.op # etc. have to be adapted;
  5313 
  5314 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5315 disabled by default; run isabelle with option -m HOL to get back to
  5316 the original Gordon/HOL-style output;
  5317 
  5318 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5319 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5320 
  5321 * HOL basic syntax simplified (more orthogonal): all variants of
  5322 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5323 Eps operator is provided as well: "SOME x. P[x]";
  5324 
  5325 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5326 
  5327 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5328 thus available for user theories;
  5329 
  5330 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5331 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5332 time;
  5333 
  5334 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5335 several times and then mp;
  5336 
  5337 
  5338 *** LK ***
  5339 
  5340 * the notation <<...>> is now available as a notation for sequences of
  5341 formulas;
  5342 
  5343 * the simplifier is now installed
  5344 
  5345 * the axiom system has been generalized (thanks to Soren Heilmann)
  5346 
  5347 * the classical reasoner now has a default rule database
  5348 
  5349 
  5350 *** ZF ***
  5351 
  5352 * new primrec section allows primitive recursive functions to be given
  5353 directly (as in HOL) over datatypes and the natural numbers;
  5354 
  5355 * new tactics induct_tac and exhaust_tac for induction (or case
  5356 analysis) over datatypes and the natural numbers;
  5357 
  5358 * the datatype declaration of type T now defines the recursor T_rec;
  5359 
  5360 * simplification automatically does freeness reasoning for datatype
  5361 constructors;
  5362 
  5363 * automatic type-inference, with AddTCs command to insert new
  5364 type-checking rules;
  5365 
  5366 * datatype introduction rules are now added as Safe Introduction rules
  5367 to the claset;
  5368 
  5369 * the syntax "if P then x else y" is now available in addition to
  5370 if(P,x,y);
  5371 
  5372 
  5373 *** Internal programming interfaces ***
  5374 
  5375 * tuned simplifier trace output; new flag debug_simp;
  5376 
  5377 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5378 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5379 
  5380 * AxClass.axclass_tac lost the theory argument;
  5381 
  5382 * tuned current_goals_markers semantics: begin / end goal avoids
  5383 printing empty lines;
  5384 
  5385 * removed prs and prs_fn hook, which was broken because it did not
  5386 include \n in its semantics, forcing writeln to add one
  5387 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5388 string -> unit if you really want to output text without newline;
  5389 
  5390 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5391 plain output, interface builders may have to enable 'isabelle_font'
  5392 mode to get Isabelle font glyphs as before;
  5393 
  5394 * refined token_translation interface; INCOMPATIBILITY: output length
  5395 now of type real instead of int;
  5396 
  5397 * theory loader actions may be traced via new ThyInfo.add_hook
  5398 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5399 your own database of information attached to *whole* theories -- as
  5400 opposed to intra-theory data slots offered via TheoryDataFun;
  5401 
  5402 * proper handling of dangling sort hypotheses (at last!);
  5403 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5404 extra sort hypotheses that can be witnessed from the type signature;
  5405 the force_strip_shyps flag is gone, any remaining shyps are simply
  5406 left in the theorem (with a warning issued by strip_shyps_warning);
  5407 
  5408 
  5409 
  5410 New in Isabelle98-1 (October 1998)
  5411 ----------------------------------
  5412 
  5413 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5414 
  5415 * several changes of automated proof tools;
  5416 
  5417 * HOL: major changes to the inductive and datatype packages, including
  5418 some minor incompatibilities of theory syntax;
  5419 
  5420 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5421 called `inj_on';
  5422 
  5423 * HOL: removed duplicate thms in Arith:
  5424   less_imp_add_less  should be replaced by  trans_less_add1
  5425   le_imp_add_le      should be replaced by  trans_le_add1
  5426 
  5427 * HOL: unary minus is now overloaded (new type constraints may be
  5428 required);
  5429 
  5430 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5431 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5432 now taken as an integer constant.
  5433 
  5434 * Pure: ML function 'theory_of' renamed to 'theory';
  5435 
  5436 
  5437 *** Proof tools ***
  5438 
  5439 * Simplifier:
  5440   1. Asm_full_simp_tac is now more aggressive.
  5441      1. It will sometimes reorient premises if that increases their power to
  5442         simplify.
  5443      2. It does no longer proceed strictly from left to right but may also
  5444         rotate premises to achieve further simplification.
  5445      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5446      old Asm_full_simp_tac in that it does not rotate premises.
  5447   2. The simplifier now knows a little bit about nat-arithmetic.
  5448 
  5449 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5450 allows for selected deletion of wrappers, by introduction of names for
  5451 wrapper functionals.  This implies that addbefore, addSbefore,
  5452 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5453 and that adding two tactics with the same name overwrites the first
  5454 one (emitting a warning).
  5455   type wrapper = (int -> tactic) -> (int -> tactic)
  5456   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5457   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5458   delWrapper, delSWrapper: claset *  string            -> claset
  5459   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5460 
  5461 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5462 semantics; addbefore now affects only the unsafe part of step_tac
  5463 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5464 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5465 by Force_tac;
  5466 
  5467 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5468 compWrapper; added safe wrapper (and access functions for it);
  5469 
  5470 * HOL/split_all_tac is now much faster and fails if there is nothing
  5471 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5472 and the names of the automatically generated variables have changed.
  5473 split_all_tac has moved within claset() from unsafe wrappers to safe
  5474 wrappers, which means that !!-bound variables are split much more
  5475 aggressively, and safe_tac and clarify_tac now split such variables.
  5476 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5477 Note: the same holds for record_split_tac, which does the job of
  5478 split_all_tac for record fields.
  5479 
  5480 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5481 permanently to the default simpset using Addsplits just like
  5482 Addsimps. They can be removed via Delsplits just like
  5483 Delsimps. Lower-case versions are also available.
  5484 
  5485 * HOL/Simplifier: The rule split_if is now part of the default
  5486 simpset. This means that the simplifier will eliminate all occurrences
  5487 of if-then-else in the conclusion of a goal. To prevent this, you can
  5488 either remove split_if completely from the default simpset by
  5489 `Delsplits [split_if]' or remove it in a specific call of the
  5490 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5491 other case splitting rules to/from the default simpset: every datatype
  5492 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5493 t is the name of the datatype).
  5494 
  5495 * Classical reasoner / Simplifier combination: new force_tac (and
  5496 derivatives Force_tac, force) combines rewriting and classical
  5497 reasoning (and whatever other tools) similarly to auto_tac, but is
  5498 aimed to solve the given subgoal completely.
  5499 
  5500 
  5501 *** General ***
  5502 
  5503 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5504 and `goalw': the theory is no longer needed as an explicit argument -
  5505 the current theory context is used; assumptions are no longer returned
  5506 at the ML-level unless one of them starts with ==> or !!; it is
  5507 recommended to convert to these new commands using isatool fixgoal
  5508 (backup your sources first!);
  5509 
  5510 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5511 the current theory context, and 'theory' to lookup stored theories;
  5512 
  5513 * new theory section 'locale' for declaring constants, assumptions and
  5514 definitions that have local scope;
  5515 
  5516 * new theory section 'nonterminals' for purely syntactic types;
  5517 
  5518 * new theory section 'setup' for generic ML setup functions
  5519 (e.g. package initialization);
  5520 
  5521 * the distribution now includes Isabelle icons: see
  5522 lib/logo/isabelle-{small,tiny}.xpm;
  5523 
  5524 * isatool install - install binaries with absolute references to
  5525 ISABELLE_HOME/bin;
  5526 
  5527 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5528 
  5529 * print mode 'emacs' reserved for Isamode;
  5530 
  5531 * support multiple print (ast) translations per constant name;
  5532 
  5533 * theorems involving oracles are now printed with a suffixed [!];
  5534 
  5535 
  5536 *** HOL ***
  5537 
  5538 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5539 
  5540 * HOL/inductive package reorganized and improved: now supports mutual
  5541 definitions such as
  5542 
  5543   inductive EVEN ODD
  5544     intrs
  5545       null "0 : EVEN"
  5546       oddI "n : EVEN ==> Suc n : ODD"
  5547       evenI "n : ODD ==> Suc n : EVEN"
  5548 
  5549 new theorem list "elims" contains an elimination rule for each of the
  5550 recursive sets; inductive definitions now handle disjunctive premises
  5551 correctly (also ZF);
  5552 
  5553 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5554 "mutual_induct" no longer exists - the induction rule is always
  5555 contained in "induct";
  5556 
  5557 
  5558 * HOL/datatype package re-implemented and greatly improved: now
  5559 supports mutually recursive datatypes such as
  5560 
  5561   datatype
  5562     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5563             | SUM ('a aexp) ('a aexp)
  5564             | DIFF ('a aexp) ('a aexp)
  5565             | NUM 'a
  5566   and
  5567     'a bexp = LESS ('a aexp) ('a aexp)
  5568             | AND ('a bexp) ('a bexp)
  5569             | OR ('a bexp) ('a bexp)
  5570 
  5571 as well as indirectly recursive datatypes such as
  5572 
  5573   datatype
  5574     ('a, 'b) term = Var 'a
  5575                   | App 'b ((('a, 'b) term) list)
  5576 
  5577 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5578 induction on mutually / indirectly recursive datatypes.
  5579 
  5580 Primrec equations are now stored in theory and can be accessed via
  5581 <function_name>.simps.
  5582 
  5583 INCOMPATIBILITIES:
  5584 
  5585   - Theories using datatypes must now have theory Datatype as an
  5586     ancestor.
  5587   - The specific <typename>.induct_tac no longer exists - use the
  5588     generic induct_tac instead.
  5589   - natE has been renamed to nat.exhaust - use exhaust_tac
  5590     instead of res_inst_tac ... natE. Note that the variable
  5591     names in nat.exhaust differ from the names in natE, this
  5592     may cause some "fragile" proofs to fail.
  5593   - The theorems split_<typename>_case and split_<typename>_case_asm
  5594     have been renamed to <typename>.split and <typename>.split_asm.
  5595   - Since default sorts of type variables are now handled correctly,
  5596     some datatype definitions may have to be annotated with explicit
  5597     sort constraints.
  5598   - Primrec definitions no longer require function name and type
  5599     of recursive argument.
  5600 
  5601 Consider using isatool fixdatatype to adapt your theories and proof
  5602 scripts to the new package (backup your sources first!).
  5603 
  5604 
  5605 * HOL/record package: considerably improved implementation; now
  5606 includes concrete syntax for record types, terms, updates; theorems
  5607 for surjective pairing and splitting !!-bound record variables; proof
  5608 support is as follows:
  5609 
  5610   1) standard conversions (selectors or updates applied to record
  5611 constructor terms) are part of the standard simpset;
  5612 
  5613   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5614 made part of standard simpset and claset via addIffs;
  5615 
  5616   3) a tactic for record field splitting (record_split_tac) is part of
  5617 the standard claset (addSWrapper);
  5618 
  5619 To get a better idea about these rules you may retrieve them via
  5620 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5621 the name of your record type.
  5622 
  5623 The split tactic 3) conceptually simplifies by the following rule:
  5624 
  5625   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5626 
  5627 Thus any record variable that is bound by meta-all will automatically
  5628 blow up into some record constructor term, consequently the
  5629 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5630 solve record problems automatically.
  5631 
  5632 
  5633 * reorganized the main HOL image: HOL/Integ and String loaded by
  5634 default; theory Main includes everything;
  5635 
  5636 * automatic simplification of integer sums and comparisons, using cancellation;
  5637 
  5638 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5639 
  5640 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5641 
  5642 * many new identities for unions, intersections, set difference, etc.;
  5643 
  5644 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5645 called split_if, split_split, split_sum_case and split_nat_case (to go
  5646 with add/delsplits);
  5647 
  5648 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5649 (?x::unit) = (); this is made part of the default simpset, which COULD
  5650 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5651 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5652 unit_abs_eta_conv is added in order to counter the effect of
  5653 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5654 %u.f();
  5655 
  5656 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5657 makes more sense);
  5658 
  5659 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5660   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5661   disjointness reasoning but breaking a few old proofs.
  5662 
  5663 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5664 to 'converse' from 'inverse' (for compatibility with ZF and some
  5665 literature);
  5666 
  5667 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5668 the well-founded relation;
  5669 
  5670 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5671     Compl A.  The "Compl" syntax remains available as input syntax for this
  5672     release ONLY.
  5673 
  5674 * HOL/Update: new theory of function updates:
  5675     f(a:=b) == %x. if x=a then b else f x
  5676 may also be iterated as in f(a:=b,c:=d,...);
  5677 
  5678 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5679 
  5680 * HOL/List:
  5681   - new function list_update written xs[i:=v] that updates the i-th
  5682     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5683   - new function `upt' written [i..j(] which generates the list
  5684     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5685     bound write [i..j], which is a shorthand for [i..j+1(].
  5686   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5687 
  5688 * HOL/Arith:
  5689   - removed 'pred' (predecessor) function;
  5690   - generalized some theorems about n-1;
  5691   - many new laws about "div" and "mod";
  5692   - new laws about greatest common divisors (see theory ex/Primes);
  5693 
  5694 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5695 instead of "inverse";
  5696 
  5697 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5698   of the multiset ordering;
  5699 
  5700 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5701   (not included by default);
  5702 
  5703 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5704 
  5705 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5706   programs, i.e. different program variables may have different types.
  5707 
  5708 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5709   [previously, this check worked only if the rewrite rule was unconditional]
  5710   Now rew can involve either definitions or equalities (either == or =).
  5711 
  5712 
  5713 *** ZF ***
  5714 
  5715 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5716   only the theorems proved on ZF.ML;
  5717 
  5718 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5719   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5720   disjointness reasoning but breaking a few old proofs.
  5721 
  5722 * ZF/Update: new theory of function updates
  5723     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5724   may also be iterated as in f(a:=b,c:=d,...);
  5725 
  5726 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5727 
  5728 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5729   [previously, this check worked only if the rewrite rule was unconditional]
  5730   Now rew can involve either definitions or equalities (either == or =).
  5731 
  5732 * case_tac provided for compatibility with HOL
  5733     (like the old excluded_middle_tac, but with subgoals swapped)
  5734 
  5735 
  5736 *** Internal programming interfaces ***
  5737 
  5738 * Pure: several new basic modules made available for general use, see
  5739 also src/Pure/README;
  5740 
  5741 * improved the theory data mechanism to support encapsulation (data
  5742 kind name replaced by private Object.kind, acting as authorization
  5743 key); new type-safe user interface via functor TheoryDataFun; generic
  5744 print_data function becomes basically useless;
  5745 
  5746 * removed global_names compatibility flag -- all theory declarations
  5747 are qualified by default;
  5748 
  5749 * module Pure/Syntax now offers quote / antiquote translation
  5750 functions (useful for Hoare logic etc. with implicit dependencies);
  5751 see HOL/ex/Antiquote for an example use;
  5752 
  5753 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5754 cterm -> thm;
  5755 
  5756 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5757 subgoal;
  5758 
  5759 * Display.print_goals function moved to Locale.print_goals;
  5760 
  5761 * standard print function for goals supports current_goals_markers
  5762 variable for marking begin of proof, end of proof, start of goal; the
  5763 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5764 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5765 for example;
  5766 
  5767 
  5768 
  5769 New in Isabelle98 (January 1998)
  5770 --------------------------------
  5771 
  5772 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5773 
  5774 * changed lexical syntax of terms / types: dots made part of long
  5775 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5776 
  5777 * simpset (and claset) reference variable replaced by functions
  5778 simpset / simpset_ref;
  5779 
  5780 * no longer supports theory aliases (via merge) and non-trivial
  5781 implicit merge of thms' signatures;
  5782 
  5783 * most internal names of constants changed due to qualified names;
  5784 
  5785 * changed Pure/Sequence interface (see Pure/seq.ML);
  5786 
  5787 
  5788 *** General Changes ***
  5789 
  5790 * hierachically structured name spaces (for consts, types, axms, thms
  5791 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5792 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5793 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5794 long_names for fully qualified output names; NOTE: ML programs
  5795 (special tactics, packages etc.) referring to internal names may have
  5796 to be adapted to cope with fully qualified names; in case of severe
  5797 backward campatibility problems try setting 'global_names' at compile
  5798 time to have enrything declared within a flat name space; one may also
  5799 fine tune name declarations in theories via the 'global' and 'local'
  5800 section;
  5801 
  5802 * reimplemented the implicit simpset and claset using the new anytype
  5803 data filed in signatures; references simpset:simpset ref etc. are
  5804 replaced by functions simpset:unit->simpset and
  5805 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5806 to patch your ML files accordingly;
  5807 
  5808 * HTML output now includes theory graph data for display with Java
  5809 applet or isatool browser; data generated automatically via isatool
  5810 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5811 
  5812 * defs may now be conditional; improved rewrite_goals_tac to handle
  5813 conditional equations;
  5814 
  5815 * defs now admits additional type arguments, using TYPE('a) syntax;
  5816 
  5817 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5818 creates a new theory node; implicit merge of thms' signatures is
  5819 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5820 transfer:theory->thm->thm in (rare) cases;
  5821 
  5822 * improved handling of draft signatures / theories; draft thms (and
  5823 ctyps, cterms) are automatically promoted to real ones;
  5824 
  5825 * slightly changed interfaces for oracles: admit many per theory, named
  5826 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5827 
  5828 * print_goals: optional output of const types (set show_consts and
  5829 show_types);
  5830 
  5831 * improved output of warnings (###) and errors (***);
  5832 
  5833 * subgoal_tac displays a warning if the new subgoal has type variables;
  5834 
  5835 * removed old README and Makefiles;
  5836 
  5837 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5838 
  5839 * removed obsolete init_pps and init_database;
  5840 
  5841 * deleted the obsolete tactical STATE, which was declared by
  5842     fun STATE tacfun st = tacfun st st;
  5843 
  5844 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5845 (which abbreviates $HOME);
  5846 
  5847 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5848 use isatool fixseq to adapt your ML programs (this works for fully
  5849 qualified references to the Sequence structure only!);
  5850 
  5851 * use_thy no longer requires writable current directory; it always
  5852 reloads .ML *and* .thy file, if either one is out of date;
  5853 
  5854 
  5855 *** Classical Reasoner ***
  5856 
  5857 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5858 tactics that use classical reasoning to simplify a subgoal without
  5859 splitting it into several subgoals;
  5860 
  5861 * Safe_tac: like safe_tac but uses the default claset;
  5862 
  5863 
  5864 *** Simplifier ***
  5865 
  5866 * added simplification meta rules:
  5867     (asm_)(full_)simplify: simpset -> thm -> thm;
  5868 
  5869 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5870 logics (again);
  5871 
  5872 * added prems argument to simplification procedures;
  5873 
  5874 * HOL, FOL, ZF: added infix function `addsplits':
  5875   instead of `<simpset> setloop (split_tac <thms>)'
  5876   you can simply write `<simpset> addsplits <thms>'
  5877 
  5878 
  5879 *** Syntax ***
  5880 
  5881 * TYPE('a) syntax for type reflection terms;
  5882 
  5883 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5884 
  5885 * pretty printer: changed order of mixfix annotation preference (again!);
  5886 
  5887 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5888 
  5889 
  5890 *** HOL ***
  5891 
  5892 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5893   with `addloop' of the simplifier to faciliate case splitting in premises.
  5894 
  5895 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5896 
  5897 * HOL/Auth: new protocol proofs including some for the Internet
  5898   protocol TLS;
  5899 
  5900 * HOL/Map: new theory of `maps' a la VDM;
  5901 
  5902 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5903 cancelling out common nat summands from =, <, <= (in)equalities, or
  5904 differences; simplification procedures nat_cancel_factor for
  5905 cancelling common factor from =, <, <= (in)equalities over natural
  5906 sums; nat_cancel contains both kinds of procedures, it is installed by
  5907 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5908 
  5909 * HOL/simplifier: terms of the form
  5910   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5911   are rewritten to
  5912   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5913   and those of the form
  5914   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5915   are rewritten to
  5916   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5917 
  5918 * HOL/datatype
  5919   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5920 
  5921   P(t_case f1 ... fn x) =
  5922      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5923         ...
  5924        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5925      )
  5926 
  5927   and a theorem `split_t_case_asm' of the form
  5928 
  5929   P(t_case f1 ... fn x) =
  5930     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5931         ...
  5932        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5933      )
  5934   which can be added to a simpset via `addsplits'. The existing theorems
  5935   expand_list_case and expand_option_case have been renamed to
  5936   split_list_case and split_option_case.
  5937 
  5938 * HOL/Arithmetic:
  5939   - `pred n' is automatically converted to `n-1'.
  5940     Users are strongly encouraged not to use `pred' any longer,
  5941     because it will disappear altogether at some point.
  5942   - Users are strongly encouraged to write "0 < n" rather than
  5943     "n ~= 0". Theorems and proof tools have been modified towards this
  5944     `standard'.
  5945 
  5946 * HOL/Lists:
  5947   the function "set_of_list" has been renamed "set" (and its theorems too);
  5948   the function "nth" now takes its arguments in the reverse order and
  5949   has acquired the infix notation "!" as in "xs!n".
  5950 
  5951 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5952 
  5953 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5954   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5955 
  5956 * HOL/record: extensible records with schematic structural subtyping
  5957 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5958 still lacks various theorems and concrete record syntax;
  5959 
  5960 
  5961 *** HOLCF ***
  5962 
  5963 * removed "axioms" and "generated by" sections;
  5964 
  5965 * replaced "ops" section by extended "consts" section, which is capable of
  5966   handling the continuous function space "->" directly;
  5967 
  5968 * domain package:
  5969   . proves theorems immediately and stores them in the theory,
  5970   . creates hierachical name space,
  5971   . now uses normal mixfix annotations (instead of cinfix...),
  5972   . minor changes to some names and values (for consistency),
  5973   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5974   . separator between mutual domain defs: changed "," to "and",
  5975   . improved handling of sort constraints;  now they have to
  5976     appear on the left-hand side of the equations only;
  5977 
  5978 * fixed LAM <x,y,zs>.b syntax;
  5979 
  5980 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5981 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5982 
  5983 
  5984 *** FOL and ZF ***
  5985 
  5986 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5987   with `addloop' of the simplifier to faciliate case splitting in premises.
  5988 
  5989 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5990 in HOL, they strip ALL and --> from proved theorems;
  5991 
  5992 
  5993 
  5994 New in Isabelle94-8 (May 1997)
  5995 ------------------------------
  5996 
  5997 *** General Changes ***
  5998 
  5999 * new utilities to build / run / maintain Isabelle etc. (in parts
  6000 still somewhat experimental); old Makefiles etc. still functional;
  6001 
  6002 * new 'Isabelle System Manual';
  6003 
  6004 * INSTALL text, together with ./configure and ./build scripts;
  6005 
  6006 * reimplemented type inference for greater efficiency, better error
  6007 messages and clean internal interface;
  6008 
  6009 * prlim command for dealing with lots of subgoals (an easier way of
  6010 setting goals_limit);
  6011 
  6012 
  6013 *** Syntax ***
  6014 
  6015 * supports alternative (named) syntax tables (parser and pretty
  6016 printer); internal interface is provided by add_modesyntax(_i);
  6017 
  6018 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6019 be used in conjunction with the Isabelle symbol font; uses the
  6020 "symbols" syntax table;
  6021 
  6022 * added token_translation interface (may translate name tokens in
  6023 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6024 the current print_mode); IMPORTANT: user print translation functions
  6025 are responsible for marking newly introduced bounds
  6026 (Syntax.mark_boundT);
  6027 
  6028 * token translations for modes "xterm" and "xterm_color" that display
  6029 names in bold, underline etc. or colors (which requires a color
  6030 version of xterm);
  6031 
  6032 * infixes may now be declared with names independent of their syntax;
  6033 
  6034 * added typed_print_translation (like print_translation, but may
  6035 access type of constant);
  6036 
  6037 
  6038 *** Classical Reasoner ***
  6039 
  6040 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6041 some limitations.  Blast_tac...
  6042   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6043   + ignores elimination rules that don't have the correct format
  6044         (the conclusion MUST be a formula variable)
  6045   + ignores types, which can make HOL proofs fail
  6046   + rules must not require higher-order unification, e.g. apply_type in ZF
  6047     [message "Function Var's argument not a bound variable" relates to this]
  6048   + its proof strategy is more general but can actually be slower
  6049 
  6050 * substitution with equality assumptions no longer permutes other
  6051 assumptions;
  6052 
  6053 * minor changes in semantics of addafter (now called addaltern); renamed
  6054 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6055 (and access functions for it);
  6056 
  6057 * improved combination of classical reasoner and simplifier:
  6058   + functions for handling clasimpsets
  6059   + improvement of addss: now the simplifier is called _after_ the
  6060     safe steps.
  6061   + safe variant of addss called addSss: uses safe simplifications
  6062     _during_ the safe steps. It is more complete as it allows multiple
  6063     instantiations of unknowns (e.g. with slow_tac).
  6064 
  6065 *** Simplifier ***
  6066 
  6067 * added interface for simplification procedures (functions that
  6068 produce *proven* rewrite rules on the fly, depending on current
  6069 redex);
  6070 
  6071 * ordering on terms as parameter (used for ordered rewriting);
  6072 
  6073 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6074 
  6075 * the solver is now split into a safe and an unsafe part.
  6076 This should be invisible for the normal user, except that the
  6077 functions setsolver and addsolver have been renamed to setSolver and
  6078 addSolver; added safe_asm_full_simp_tac;
  6079 
  6080 
  6081 *** HOL ***
  6082 
  6083 * a generic induction tactic `induct_tac' which works for all datatypes and
  6084 also for type `nat';
  6085 
  6086 * a generic case distinction tactic `exhaust_tac' which works for all
  6087 datatypes and also for type `nat';
  6088 
  6089 * each datatype comes with a function `size';
  6090 
  6091 * patterns in case expressions allow tuple patterns as arguments to
  6092 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6093 
  6094 * primrec now also works with type nat;
  6095 
  6096 * recdef: a new declaration form, allows general recursive functions to be
  6097 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6098 
  6099 * the constant for negation has been renamed from "not" to "Not" to
  6100 harmonize with FOL, ZF, LK, etc.;
  6101 
  6102 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6103 infinite lists;
  6104 
  6105 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6106 
  6107 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6108 problems in commutative rings, using axiomatic type classes for + and *;
  6109 
  6110 * more examples in HOL/MiniML and HOL/Auth;
  6111 
  6112 * more default rewrite rules for quantifiers, union/intersection;
  6113 
  6114 * a new constant `arbitrary == @x.False';
  6115 
  6116 * HOLCF/IOA replaces old HOL/IOA;
  6117 
  6118 * HOLCF changes: derived all rules and arities
  6119   + axiomatic type classes instead of classes
  6120   + typedef instead of faking type definitions
  6121   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6122   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6123   + eliminated the types void, one, tr
  6124   + use unit lift and bool lift (with translations) instead of one and tr
  6125   + eliminated blift from Lift3.thy (use Def instead of blift)
  6126   all eliminated rules are derived as theorems --> no visible changes ;
  6127 
  6128 
  6129 *** ZF ***
  6130 
  6131 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6132 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6133 as ZF_cs addSIs [equalityI];
  6134 
  6135 
  6136 
  6137 New in Isabelle94-7 (November 96)
  6138 ---------------------------------
  6139 
  6140 * allowing negative levels (as offsets) in prlev and choplev;
  6141 
  6142 * super-linear speedup for large simplifications;
  6143 
  6144 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6145 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6146 FAIL); can suppress it using the command Delsimps (ex_simps @
  6147 all_simps); De Morgan laws are also now included, by default;
  6148 
  6149 * improved printing of ==>  :  ~:
  6150 
  6151 * new object-logic "Sequents" adds linear logic, while replacing LK
  6152 and Modal (thanks to Sara Kalvala);
  6153 
  6154 * HOL/Auth: correctness proofs for authentication protocols;
  6155 
  6156 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6157 examples on HOL/Auth);
  6158 
  6159 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6160 the rewriter and classical reasoner simultaneously;
  6161 
  6162 * function uresult no longer returns theorems in "standard" format;
  6163 regain previous version by: val uresult = standard o uresult;
  6164 
  6165 
  6166 
  6167 New in Isabelle94-6
  6168 -------------------
  6169 
  6170 * oracles -- these establish an interface between Isabelle and trusted
  6171 external reasoners, which may deliver results as theorems;
  6172 
  6173 * proof objects (in particular record all uses of oracles);
  6174 
  6175 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6176 
  6177 * "constdefs" section in theory files;
  6178 
  6179 * "primrec" section (HOL) no longer requires names;
  6180 
  6181 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6182 
  6183 
  6184 
  6185 New in Isabelle94-5
  6186 -------------------
  6187 
  6188 * reduced space requirements;
  6189 
  6190 * automatic HTML generation from theories;
  6191 
  6192 * theory files no longer require "..." (quotes) around most types;
  6193 
  6194 * new examples, including two proofs of the Church-Rosser theorem;
  6195 
  6196 * non-curried (1994) version of HOL is no longer distributed;
  6197 
  6198 
  6199 
  6200 New in Isabelle94-4
  6201 -------------------
  6202 
  6203 * greatly reduced space requirements;
  6204 
  6205 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6206 
  6207 * searchable theorem database (see the section "Retrieving theorems" on
  6208 page 8 of the Reference Manual);
  6209 
  6210 * new examples, including Grabczewski's monumental case study of the
  6211 Axiom of Choice;
  6212 
  6213 * The previous version of HOL renamed to Old_HOL;
  6214 
  6215 * The new version of HOL (previously called CHOL) uses a curried syntax
  6216 for functions.  Application looks like f a b instead of f(a,b);
  6217 
  6218 * Mutually recursive inductive definitions finally work in HOL;
  6219 
  6220 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6221 translates to the operator "split";
  6222 
  6223 
  6224 
  6225 New in Isabelle94-3
  6226 -------------------
  6227 
  6228 * new infix operator, addss, allowing the classical reasoner to
  6229 perform simplification at each step of its search.  Example:
  6230         fast_tac (cs addss ss)
  6231 
  6232 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6233 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6234 look like (a,b) instead of <a,b>;
  6235 
  6236 * PLEASE NOTE: CHOL will eventually replace HOL!
  6237 
  6238 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6239 It translates to the operator "split".  A new theory of integers is available;
  6240 
  6241 * In ZF, integer numerals now denote two's-complement binary integers.
  6242 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6243 
  6244 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6245 of the Axiom of Choice;
  6246 
  6247 
  6248 
  6249 New in Isabelle94-2
  6250 -------------------
  6251 
  6252 * Significantly faster resolution;
  6253 
  6254 * the different sections in a .thy file can now be mixed and repeated
  6255 freely;
  6256 
  6257 * Database of theorems for FOL, HOL and ZF.  New
  6258 commands including qed, qed_goal and bind_thm store theorems in the database.
  6259 
  6260 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6261 a given theory (thms_of), or f