NEWS
author haftmann
Fri Apr 24 17:45:15 2009 +0200 (2009-04-24)
changeset 30971 7fbebf75b3ef
parent 30965 e0938d929bfd
child 31001 7e6ffd8f51a9
permissions -rw-r--r--
funpow and relpow with shared "^^" syntax
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** Pure ***
     8 
     9 * On instantiation of classes, remaining undefined class parameters are
    10 formally declared.  INCOMPATIBILITY.
    11 
    12 
    13 *** HOL ***
    14 
    15 * Class semiring_div requires superclass no_zero_divisors and proof of div_mult_mult1;
    16 theorems div_mult_mult1, div_mult_mult2, div_mult_mult1_if, div_mult_mult1 and
    17 div_mult_mult2 have been generalized to class semiring_div, subsuming former
    18 theorems zdiv_zmult_zmult1, zdiv_zmult_zmult1_if, zdiv_zmult_zmult1 and zdiv_zmult_zmult2.
    19 div_mult_mult1 is now [simp] by default.  INCOMPATIBILITY.
    20 
    21 * Power operations on relations and functions are now one dedicate constant compow with
    22 infix syntax "^^".  Power operations on multiplicative monoids retains syntax "^"
    23 and is now defined generic in class recpower; class power disappeared.  INCOMPATIBILITY.
    24 
    25 * ML antiquotation @{code_datatype} inserts definition of a datatype generated
    26 by the code generator; see Predicate.thy for an example.
    27 
    28 
    29 New in Isabelle2009 (April 2009)
    30 --------------------------------
    31 
    32 *** General ***
    33 
    34 * Simplified main Isabelle executables, with less surprises on
    35 case-insensitive file-systems (such as Mac OS).
    36 
    37   - The main Isabelle tool wrapper is now called "isabelle" instead of
    38     "isatool."
    39 
    40   - The former "isabelle" alias for "isabelle-process" has been
    41     removed (should rarely occur to regular users).
    42 
    43   - The former "isabelle-interface" and its alias "Isabelle" have been
    44     removed (interfaces are now regular Isabelle tools).
    45 
    46 Within scripts and make files, the Isabelle environment variables
    47 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    48 respectively.  (The latter are still available as legacy feature.)
    49 
    50 The old isabelle-interface wrapper could react in confusing ways if
    51 the interface was uninstalled or changed otherwise.  Individual
    52 interface tool configuration is now more explicit, see also the
    53 Isabelle system manual.  In particular, Proof General is now available
    54 via "isabelle emacs".
    55 
    56 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    57 purge installed copies of Isabelle executables and re-run "isabelle
    58 install -p ...", or use symlinks.
    59 
    60 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    61 old ~/isabelle, which was slightly non-standard and apt to cause
    62 surprises on case-insensitive file-systems (such as Mac OS).
    63 
    64 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    65 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    66 care is required when using older releases of Isabelle.  Note that
    67 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    68 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
    69 
    70 * Proofs of fully specified statements are run in parallel on
    71 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
    72 a regular 4-core machine, if the initial heap space is made reasonably
    73 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
    74 
    75 * The main reference manuals ("isar-ref", "implementation", and
    76 "system") have been updated and extended.  Formally checked references
    77 as hyperlinks are now available uniformly.
    78 
    79 
    80 *** Pure ***
    81 
    82 * Complete re-implementation of locales.  INCOMPATIBILITY in several
    83 respects.  The most important changes are listed below.  See the
    84 Tutorial on Locales ("locales" manual) for details.
    85 
    86 - In locale expressions, instantiation replaces renaming.  Parameters
    87 must be declared in a for clause.  To aid compatibility with previous
    88 parameter inheritance, in locale declarations, parameters that are not
    89 'touched' (instantiation position "_" or omitted) are implicitly added
    90 with their syntax at the beginning of the for clause.
    91 
    92 - Syntax from abbreviations and definitions in locales is available in
    93 locale expressions and context elements.  The latter is particularly
    94 useful in locale declarations.
    95 
    96 - More flexible mechanisms to qualify names generated by locale
    97 expressions.  Qualifiers (prefixes) may be specified in locale
    98 expressions, and can be marked as mandatory (syntax: "name!:") or
    99 optional (syntax "name?:").  The default depends for plain "name:"
   100 depends on the situation where a locale expression is used: in
   101 commands 'locale' and 'sublocale' prefixes are optional, in
   102 'interpretation' and 'interpret' prefixes are mandatory.  The old
   103 implicit qualifiers derived from the parameter names of a locale are
   104 no longer generated.
   105 
   106 - Command "sublocale l < e" replaces "interpretation l < e".  The
   107 instantiation clause in "interpretation" and "interpret" (square
   108 brackets) is no longer available.  Use locale expressions.
   109 
   110 - When converting proof scripts, mandatory qualifiers in
   111 'interpretation' and 'interpret' should be retained by default, even
   112 if this is an INCOMPATIBILITY compared to former behavior.  In the
   113 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   114 in locale expressions range over a single locale instance only.
   115 
   116 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   117 In existing theorem specifications replace the includes element by the
   118 respective context elements of the included locale, omitting those
   119 that are already present in the theorem specification.  Multiple
   120 assume elements of a locale should be replaced by a single one
   121 involving the locale predicate.  In the proof body, declarations (most
   122 notably theorems) may be regained by interpreting the respective
   123 locales in the proof context as required (command "interpret").
   124 
   125 If using "includes" in replacement of a target solely because the
   126 parameter types in the theorem are not as general as in the target,
   127 consider declaring a new locale with additional type constraints on
   128 the parameters (context element "constrains").
   129 
   130 - Discontinued "locale (open)".  INCOMPATIBILITY.
   131 
   132 - Locale interpretation commands no longer attempt to simplify goal.
   133 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   134 methods intro_locales and unfold_locales to clarify.
   135 
   136 - Locale interpretation commands no longer accept interpretation
   137 attributes.  INCOMPATIBILITY.
   138 
   139 * Class declaration: so-called "base sort" must not be given in import
   140 list any longer, but is inferred from the specification.  Particularly
   141 in HOL, write
   142 
   143     class foo = ...
   144 
   145 instead of
   146 
   147     class foo = type + ...
   148 
   149 * Class target: global versions of theorems stemming do not carry a
   150 parameter prefix any longer.  INCOMPATIBILITY.
   151 
   152 * Class 'instance' command no longer accepts attached definitions.
   153 INCOMPATIBILITY, use proper 'instantiation' target instead.
   154 
   155 * Recovered hiding of consts, which was accidentally broken in
   156 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   157 makes c inaccessible; consider using ``hide (open) const c'' instead.
   158 
   159 * Slightly more coherent Pure syntax, with updated documentation in
   160 isar-ref manual.  Removed locales meta_term_syntax and
   161 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   162 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   163 directly in regular applications.
   164 
   165 * There is a new syntactic category "float_const" for signed decimal
   166 fractions (e.g. 123.45 or -123.45).
   167 
   168 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   169 interface with 'setup' command instead.
   170 
   171 * Command 'local_setup' is similar to 'setup', but operates on a local
   172 theory context.
   173 
   174 * The 'axiomatization' command now only works within a global theory
   175 context.  INCOMPATIBILITY.
   176 
   177 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   178 hypotheses.  Sorts required in the course of reasoning need to be
   179 covered by the constraints in the initial statement, completed by the
   180 type instance information of the background theory.  Non-trivial sort
   181 hypotheses, which rarely occur in practice, may be specified via
   182 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   183 
   184   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   185 
   186 The result contains an implicit sort hypotheses as before --
   187 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   188 normalization.
   189 
   190 * Generalized Isar history, with support for linear undo, direct state
   191 addressing etc.
   192 
   193 * Changed defaults for unify configuration options:
   194 
   195   unify_trace_bound = 50 (formerly 25)
   196   unify_search_bound = 60 (formerly 30)
   197 
   198 * Different bookkeeping for code equations (INCOMPATIBILITY):
   199 
   200   a) On theory merge, the last set of code equations for a particular
   201      constant is taken (in accordance with the policy applied by other
   202      parts of the code generator framework).
   203 
   204   b) Code equations stemming from explicit declarations (e.g. code
   205      attribute) gain priority over default code equations stemming
   206      from definition, primrec, fun etc.
   207 
   208 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   209 
   210 * Unified theorem tables for both code generators.  Thus [code
   211 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   212 
   213 * Command 'find_consts' searches for constants based on type and name
   214 patterns, e.g.
   215 
   216     find_consts "_ => bool"
   217 
   218 By default, matching is against subtypes, but it may be restricted to
   219 the whole type.  Searching by name is possible.  Multiple queries are
   220 conjunctive and queries may be negated by prefixing them with a
   221 hyphen:
   222 
   223     find_consts strict: "_ => bool" name: "Int" -"int => int"
   224 
   225 * New 'find_theorems' criterion "solves" matches theorems that
   226 directly solve the current goal (modulo higher-order unification).
   227 
   228 * Auto solve feature for main theorem statements: whenever a new goal
   229 is stated, "find_theorems solves" is called; any theorems that could
   230 solve the lemma directly are listed as part of the goal state.
   231 Cf. associated options in Proof General Isabelle settings menu,
   232 enabled by default, with reasonable timeout for pathological cases of
   233 higher-order unification.
   234 
   235 
   236 *** Document preparation ***
   237 
   238 * Antiquotation @{lemma} now imitates a regular terminal proof,
   239 demanding keyword 'by' and supporting the full method expression
   240 syntax just like the Isar command 'by'.
   241 
   242 
   243 *** HOL ***
   244 
   245 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   246 points Main and Complex_Main remain as before.
   247 
   248 * Logic image HOL-Plain provides a minimal HOL with the most important
   249 tools available (inductive, datatype, primrec, ...).  This facilitates
   250 experimentation and tool development.  Note that user applications
   251 (and library theories) should never refer to anything below theory
   252 Main, as before.
   253 
   254 * Logic image HOL-Main stops at theory Main, and thus facilitates
   255 experimentation due to shorter build times.
   256 
   257 * Logic image HOL-NSA contains theories of nonstandard analysis which
   258 were previously part of former HOL-Complex.  Entry point Hyperreal
   259 remains valid, but theories formerly using Complex_Main should now use
   260 new entry point Hypercomplex.
   261 
   262 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   263 Posix processes.  Avoids potentially expensive forking of the ML
   264 process.  New thread-based implementation also works on non-Unix
   265 platforms (Cygwin).  Provers are no longer hardwired, but defined
   266 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   267 commands are covered in the isar-ref manual.
   268 
   269 * Wrapper scripts for remote SystemOnTPTP service allows to use
   270 sledgehammer without local ATP installation (Vampire etc.). Other
   271 provers may be included via suitable ML wrappers, see also
   272 src/HOL/ATP_Linkup.thy.
   273 
   274 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   275 menu.
   276 
   277 * The metis method no longer fails because the theorem is too trivial
   278 (contains the empty clause).
   279 
   280 * The metis method now fails in the usual manner, rather than raising
   281 an exception, if it determines that it cannot prove the theorem.
   282 
   283 * Method "coherent" implements a prover for coherent logic (see also
   284 src/Tools/coherent.ML).
   285 
   286 * Constants "undefined" and "default" replace "arbitrary".  Usually
   287 "undefined" is the right choice to replace "arbitrary", though
   288 logically there is no difference.  INCOMPATIBILITY.
   289 
   290 * Command "value" now integrates different evaluation mechanisms.  The
   291 result of the first successful evaluation mechanism is printed.  In
   292 square brackets a particular named evaluation mechanisms may be
   293 specified (currently, [SML], [code] or [nbe]).  See further
   294 src/HOL/ex/Eval_Examples.thy.
   295 
   296 * Normalization by evaluation now allows non-leftlinear equations.
   297 Declare with attribute [code nbe].
   298 
   299 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   300 as the structured Isar versions "cases" and "induct", cf. the
   301 corresponding "cases" and "induct" attributes.  Mutual induction rules
   302 are now presented as a list of individual projections
   303 (e.g. foo_bar.inducts for types foo and bar); the old format with
   304 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   305 rare situations a different rule is selected --- notably nested tuple
   306 elimination instead of former prod.exhaust: use explicit (case_tac t
   307 rule: prod.exhaust) here.
   308 
   309 * Attributes "cases", "induct", "coinduct" support "del" option.
   310 
   311 * Removed fact "case_split_thm", which duplicates "case_split".
   312 
   313 * The option datatype has been moved to a new theory Option.  Renamed
   314 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   315 
   316 * New predicate "strict_mono" classifies strict functions on partial
   317 orders.  With strict functions on linear orders, reasoning about
   318 (in)equalities is facilitated by theorems "strict_mono_eq",
   319 "strict_mono_less_eq" and "strict_mono_less".
   320 
   321 * Some set operations are now proper qualified constants with
   322 authentic syntax.  INCOMPATIBILITY:
   323 
   324     op Int ~>   Set.Int
   325     op Un ~>    Set.Un
   326     INTER ~>    Set.INTER
   327     UNION ~>    Set.UNION
   328     Inter ~>    Set.Inter
   329     Union ~>    Set.Union
   330     {} ~>       Set.empty
   331     UNIV ~>     Set.UNIV
   332 
   333 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   334 theory Set.
   335 
   336 * Auxiliary class "itself" has disappeared -- classes without any
   337 parameter are treated as expected by the 'class' command.
   338 
   339 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   340 
   341 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   342 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   343 
   344 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   345 method "approximation".  It proves formulas on real values by using
   346 interval arithmetic.  In the formulas are also the transcendental
   347 functions sin, cos, tan, atan, ln, exp and the constant pi are
   348 allowed. For examples see
   349 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   350 
   351 * Theory "Reflection" now resides in HOL/Library.
   352 
   353 * Entry point to Word library now simply named "Word".
   354 INCOMPATIBILITY.
   355 
   356 * Made source layout more coherent with logical distribution
   357 structure:
   358 
   359     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   360     src/HOL/Library/Code_Message.thy ~> src/HOL/
   361     src/HOL/Library/GCD.thy ~> src/HOL/
   362     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   363     src/HOL/Library/Parity.thy ~> src/HOL/
   364     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   365     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   366     src/HOL/Real/Lubs.thy ~> src/HOL/
   367     src/HOL/Real/PReal.thy ~> src/HOL/
   368     src/HOL/Real/Rational.thy ~> src/HOL/
   369     src/HOL/Real/RComplete.thy ~> src/HOL/
   370     src/HOL/Real/RealDef.thy ~> src/HOL/
   371     src/HOL/Real/RealPow.thy ~> src/HOL/
   372     src/HOL/Real/Real.thy ~> src/HOL/
   373     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   374     src/HOL/Complex/Complex.thy ~> src/HOL/
   375     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   376     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   377     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   378     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   379     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   380     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   381     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   382     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   383     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   384     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   385     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   386     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   387     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   388     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   389     src/HOL/Real/Float ~> src/HOL/Library/
   390     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   391     src/HOL/Real/RealVector.thy ~> src/HOL/
   392 
   393     src/HOL/arith_data.ML ~> src/HOL/Tools
   394     src/HOL/hologic.ML ~> src/HOL/Tools
   395     src/HOL/simpdata.ML ~> src/HOL/Tools
   396     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   397     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   398     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   399     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   400     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   401     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   402     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   403 
   404     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   405     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   406     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   407     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   408     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   409     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   410 
   411 * If methods "eval" and "evaluation" encounter a structured proof
   412 state with !!/==>, only the conclusion is evaluated to True (if
   413 possible), avoiding strange error messages.
   414 
   415 * Method "sizechange" automates termination proofs using (a
   416 modification of) the size-change principle.  Requires SAT solver.  See
   417 src/HOL/ex/Termination.thy for examples.
   418 
   419 * Simplifier: simproc for let expressions now unfolds if bound
   420 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   421 
   422 * Method "arith": Linear arithmetic now ignores all inequalities when
   423 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   424 
   425 * New attribute "arith" for facts that should always be used
   426 automatically by arithmetic. It is intended to be used locally in
   427 proofs, e.g.
   428 
   429   assumes [arith]: "x > 0"
   430 
   431 Global usage is discouraged because of possible performance impact.
   432 
   433 * New classes "top" and "bot" with corresponding operations "top" and
   434 "bot" in theory Orderings; instantiation of class "complete_lattice"
   435 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   436 
   437 * Changed definition lemma "less_fun_def" in order to provide an
   438 instance for preorders on functions; use lemma "less_le" instead.
   439 INCOMPATIBILITY.
   440 
   441 * Theory Orderings: class "wellorder" moved here, with explicit
   442 induction rule "less_induct" as assumption.  For instantiation of
   443 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   444 INCOMPATIBILITY.
   445 
   446 * Theory Orderings: added class "preorder" as superclass of "order".
   447 INCOMPATIBILITY: Instantiation proofs for order, linorder
   448 etc. slightly changed.  Some theorems named order_class.* now named
   449 preorder_class.*.
   450 
   451 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   452 "diag" to "Id_on".
   453 
   454 * Theory Finite_Set: added a new fold combinator of type
   455 
   456   ('a => 'b => 'b) => 'b => 'a set => 'b
   457 
   458 Occasionally this is more convenient than the old fold combinator
   459 which is now defined in terms of the new one and renamed to
   460 fold_image.
   461 
   462 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   463 and "ring_simps" have been replaced by "algebra_simps" (which can be
   464 extended with further lemmas!).  At the moment both still exist but
   465 the former will disappear at some point.
   466 
   467 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   468 class recpower.  Type-specific simp rules for various recpower types
   469 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   470 
   471 rat_power_0    -> power_0
   472 rat_power_Suc  -> power_Suc
   473 realpow_0      -> power_0
   474 realpow_Suc    -> power_Suc
   475 complexpow_0   -> power_0
   476 complexpow_Suc -> power_Suc
   477 power_poly_0   -> power_0
   478 power_poly_Suc -> power_Suc
   479 
   480 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   481 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   482 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   483 of lemmas from Divides has been generalized from nat to class
   484 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   485 renames resulting from duplicate elimination:
   486 
   487     dvd_def_mod ~>          dvd_eq_mod_eq_0
   488     zero_dvd_iff ~>         dvd_0_left_iff
   489     dvd_0 ~>                dvd_0_right
   490     DIVISION_BY_ZERO_DIV ~> div_by_0
   491     DIVISION_BY_ZERO_MOD ~> mod_by_0
   492     mult_div ~>             div_mult_self2_is_id
   493     mult_mod ~>             mod_mult_self2_is_0
   494 
   495 * Theory IntDiv: removed many lemmas that are instances of class-based
   496 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   497 rename old lemmas as follows:
   498 
   499 dvd_diff               -> nat_dvd_diff
   500 dvd_zminus_iff         -> dvd_minus_iff
   501 mod_add1_eq            -> mod_add_eq
   502 mod_mult1_eq           -> mod_mult_right_eq
   503 mod_mult1_eq'          -> mod_mult_left_eq
   504 mod_mult_distrib_mod   -> mod_mult_eq
   505 nat_mod_add_left_eq    -> mod_add_left_eq
   506 nat_mod_add_right_eq   -> mod_add_right_eq
   507 nat_mod_div_trivial    -> mod_div_trivial
   508 nat_mod_mod_trivial    -> mod_mod_trivial
   509 zdiv_zadd_self1        -> div_add_self1
   510 zdiv_zadd_self2        -> div_add_self2
   511 zdiv_zmult_self1       -> div_mult_self2_is_id
   512 zdiv_zmult_self2       -> div_mult_self1_is_id
   513 zdvd_triv_left         -> dvd_triv_left
   514 zdvd_triv_right        -> dvd_triv_right
   515 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   516 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   517 zmod_zadd_left_eq      -> mod_add_left_eq
   518 zmod_zadd_right_eq     -> mod_add_right_eq
   519 zmod_zadd_self1        -> mod_add_self1
   520 zmod_zadd_self2        -> mod_add_self2
   521 zmod_zadd1_eq          -> mod_add_eq
   522 zmod_zdiff1_eq         -> mod_diff_eq
   523 zmod_zdvd_zmod         -> mod_mod_cancel
   524 zmod_zmod_cancel       -> mod_mod_cancel
   525 zmod_zmult_self1       -> mod_mult_self2_is_0
   526 zmod_zmult_self2       -> mod_mult_self1_is_0
   527 zmod_1                 -> mod_by_1
   528 zdiv_1                 -> div_by_1
   529 zdvd_abs1              -> abs_dvd_iff
   530 zdvd_abs2              -> dvd_abs_iff
   531 zdvd_refl              -> dvd_refl
   532 zdvd_trans             -> dvd_trans
   533 zdvd_zadd              -> dvd_add
   534 zdvd_zdiff             -> dvd_diff
   535 zdvd_zminus_iff        -> dvd_minus_iff
   536 zdvd_zminus2_iff       -> minus_dvd_iff
   537 zdvd_zmultD            -> dvd_mult_right
   538 zdvd_zmultD2           -> dvd_mult_left
   539 zdvd_zmult_mono        -> mult_dvd_mono
   540 zdvd_0_right           -> dvd_0_right
   541 zdvd_0_left            -> dvd_0_left_iff
   542 zdvd_1_left            -> one_dvd
   543 zminus_dvd_iff         -> minus_dvd_iff
   544 
   545 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   546 
   547 * The real numbers offer decimal input syntax: 12.34 is translated
   548 into 1234/10^2. This translation is not reversed upon output.
   549 
   550 * Theory Library/Polynomial defines an abstract type 'a poly of
   551 univariate polynomials with coefficients of type 'a.  In addition to
   552 the standard ring operations, it also supports div and mod.  Code
   553 generation is also supported, using list-style constructors.
   554 
   555 * Theory Library/Inner_Product defines a class of real_inner for real
   556 inner product spaces, with an overloaded operation inner :: 'a => 'a
   557 => real.  Class real_inner is a subclass of real_normed_vector from
   558 theory RealVector.
   559 
   560 * Theory Library/Product_Vector provides instances for the product
   561 type 'a * 'b of several classes from RealVector and Inner_Product.
   562 Definitions of addition, subtraction, scalar multiplication, norms,
   563 and inner products are included.
   564 
   565 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   566 addition to the field operations, numerals and case syntax are also
   567 supported.
   568 
   569 * Theory Library/Diagonalize provides constructive version of Cantor's
   570 first diagonalization argument.
   571 
   572 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   573 zlcm (for int); carried together from various gcd/lcm developements in
   574 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   575 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   576 may recover tupled syntax as follows:
   577 
   578     hide (open) const gcd
   579     abbreviation gcd where
   580       "gcd == (%(a, b). GCD.gcd a b)"
   581     notation (output)
   582       GCD.gcd ("gcd '(_, _')")
   583 
   584 The same works for lcm, zgcd, zlcm.
   585 
   586 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   587 instantiations for algebraic structures.  Removed some duplicate
   588 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   589 
   590 * ML antiquotation @{code} takes a constant as argument and generates
   591 corresponding code in background and inserts name of the corresponding
   592 resulting ML value/function/datatype constructor binding in place.
   593 All occurrences of @{code} with a single ML block are generated
   594 simultaneously.  Provides a generic and safe interface for
   595 instrumentalizing code generation.  See
   596 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   597 In future you ought to refrain from ad-hoc compiling generated SML
   598 code on the ML toplevel.  Note that (for technical reasons) @{code}
   599 cannot refer to constants for which user-defined serializations are
   600 set.  Refer to the corresponding ML counterpart directly in that
   601 cases.
   602 
   603 * Command 'rep_datatype': instead of theorem names the command now
   604 takes a list of terms denoting the constructors of the type to be
   605 represented as datatype.  The characteristic theorems have to be
   606 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   607 have disappeared in favour of existing ones:
   608 
   609     unit_induct                 ~> unit.induct
   610     prod_induct                 ~> prod.induct
   611     sum_induct                  ~> sum.induct
   612     Suc_Suc_eq                  ~> nat.inject
   613     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   614 
   615 
   616 *** HOL-Algebra ***
   617 
   618 * New locales for orders and lattices where the equivalence relation
   619 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   620 locales use a record structure with field eq for the equivalence.
   621 
   622 * New theory of factorial domains.
   623 
   624 * Units_l_inv and Units_r_inv are now simp rules by default.
   625 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   626 and/or r_inv will now also require deletion of these lemmas.
   627 
   628 * Renamed the following theorems, INCOMPATIBILITY:
   629 
   630 UpperD ~> Upper_memD
   631 LowerD ~> Lower_memD
   632 least_carrier ~> least_closed
   633 greatest_carrier ~> greatest_closed
   634 greatest_Lower_above ~> greatest_Lower_below
   635 one_zero ~> carrier_one_zero
   636 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   637 
   638 
   639 *** HOL-Nominal ***
   640 
   641 * Nominal datatypes can now contain type-variables.
   642 
   643 * Commands 'nominal_inductive' and 'equivariance' work with local
   644 theory targets.
   645 
   646 * Nominal primrec can now works with local theory targets and its
   647 specification syntax now conforms to the general format as seen in
   648 'inductive' etc.
   649 
   650 * Method "perm_simp" honours the standard simplifier attributes
   651 (no_asm), (no_asm_use) etc.
   652 
   653 * The new predicate #* is defined like freshness, except that on the
   654 left hand side can be a set or list of atoms.
   655 
   656 * Experimental command 'nominal_inductive2' derives strong induction
   657 principles for inductive definitions.  In contrast to
   658 'nominal_inductive', which can only deal with a fixed number of
   659 binders, it can deal with arbitrary expressions standing for sets of
   660 atoms to be avoided.  The only inductive definition we have at the
   661 moment that needs this generalisation is the typing rule for Lets in
   662 the algorithm W:
   663 
   664  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   665  -----------------------------------------------------------------
   666          Gamma |- Let x be t1 in t2 : T2
   667 
   668 In this rule one wants to avoid all the binders that are introduced by
   669 "close Gamma T1".  We are looking for other examples where this
   670 feature might be useful.  Please let us know.
   671 
   672 
   673 *** HOLCF ***
   674 
   675 * Reimplemented the simplification procedure for proving continuity
   676 subgoals.  The new simproc is extensible; users can declare additional
   677 continuity introduction rules with the attribute [cont2cont].
   678 
   679 * The continuity simproc now uses a different introduction rule for
   680 solving continuity subgoals on terms with lambda abstractions.  In
   681 some rare cases the new simproc may fail to solve subgoals that the
   682 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   683 Potential INCOMPATIBILITY.
   684 
   685 * Command 'fixrec': specification syntax now conforms to the general
   686 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   687 examples.  INCOMPATIBILITY.
   688 
   689 
   690 *** ZF ***
   691 
   692 * Proof of Zorn's Lemma for partial orders.
   693 
   694 
   695 *** ML ***
   696 
   697 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   698 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   699 depends on multithreading, so timouts will not work before Poly/ML
   700 5.2.1!
   701 
   702 * High-level support for concurrent ML programming, see
   703 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   704 particularly convenient to organize independent functional
   705 computations.  The concept of "synchronized variables" provides a
   706 higher-order interface for components with shared state, avoiding the
   707 delicate details of mutexes and condition variables.  (Requires
   708 Poly/ML 5.2.1 or later.)
   709 
   710 * ML bindings produced via Isar commands are stored within the Isar
   711 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   712 become thread-safe and work with undo as expected (concerning
   713 top-level bindings, not side-effects on global references).
   714 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   715 compiler at runtime; really global bindings need to be given outside a
   716 theory.  (Requires Poly/ML 5.2 or later.)
   717 
   718 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   719 context.  Top-level ML bindings are stored within the proof context in
   720 a purely sequential fashion, disregarding the nested proof structure.
   721 ML bindings introduced by 'ML_prf' are discarded at the end of the
   722 proof.  (Requires Poly/ML 5.2 or later.)
   723 
   724 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   725 and Method.setup, as well as Isar commands 'attribute_setup' and
   726 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   727 existing code accordingly, or use plain 'setup' together with old
   728 Method.add_method.
   729 
   730 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   731 to 'a -> thm, while results are always tagged with an authentic oracle
   732 name.  The Isar command 'oracle' is now polymorphic, no argument type
   733 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   734 accordingly.  Note that extra performance may be gained by producing
   735 the cterm carefully, avoiding slow Thm.cterm_of.
   736 
   737 * Simplified interface for defining document antiquotations via
   738 ThyOutput.antiquotation, ThyOutput.output, and optionally
   739 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   740 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   741 examples.
   742 
   743 * More systematic treatment of long names, abstract name bindings, and
   744 name space operations.  Basic operations on qualified names have been
   745 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   746 Long_Name.append.  Old type bstring has been mostly replaced by
   747 abstract type binding (see structure Binding), which supports precise
   748 qualification by packages and local theory targets, as well as proper
   749 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   750 bstring values into Binding.name, or better pass through abstract
   751 bindings everywhere.  See further src/Pure/General/long_name.ML,
   752 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   753 
   754 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   755 LocalTheory.note etc.) now refer to the *full* internal name, not the
   756 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   757 
   758 * Disposed old type and term read functions (Sign.read_def_typ,
   759 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   760 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   761 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   762 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   763 resort for legacy applications.
   764 
   765 * Disposed old declarations, tactics, tactic combinators that refer to
   766 the simpset or claset of an implicit theory (such as Addsimps,
   767 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   768 embedded ML text, or local_simpset_of with a proper context passed as
   769 explicit runtime argument.
   770 
   771 * Rules and tactics that read instantiations (read_instantiate,
   772 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   773 context, which is required for parsing and type-checking.  Moreover,
   774 the variables are specified as plain indexnames, not string encodings
   775 thereof.  INCOMPATIBILITY.
   776 
   777 * Generic Toplevel.add_hook interface allows to analyze the result of
   778 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   779 for theorem dependency output of transactions resulting in a new
   780 theory state.
   781 
   782 * ML antiquotations: block-structured compilation context indicated by
   783 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   784 
   785   @{binding name}                         - basic name binding
   786   @{let ?pat = term}                      - term abbreviation (HO matching)
   787   @{note name = fact}                     - fact abbreviation
   788   @{thm fact}                             - singleton fact (with attributes)
   789   @{thms fact}                            - general fact (with attributes)
   790   @{lemma prop by method}                 - singleton goal
   791   @{lemma prop by meth1 meth2}            - singleton goal
   792   @{lemma prop1 ... propN by method}      - general goal
   793   @{lemma prop1 ... propN by meth1 meth2} - general goal
   794   @{lemma (open) ...}                     - open derivation
   795 
   796 
   797 *** System ***
   798 
   799 * The Isabelle "emacs" tool provides a specific interface to invoke
   800 Proof General / Emacs, with more explicit failure if that is not
   801 installed (the old isabelle-interface script silently falls back on
   802 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   803 installation location of the Proof General distribution.
   804 
   805 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   806 the Isabelle process into a JVM/Scala application.  See
   807 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   808 process wrapper has been discontinued.)
   809 
   810 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   811 
   812 * Various status messages (with exact source position information) are
   813 emitted, if proper markup print mode is enabled.  This allows
   814 user-interface components to provide detailed feedback on internal
   815 prover operations.
   816 
   817 
   818 
   819 New in Isabelle2008 (June 2008)
   820 -------------------------------
   821 
   822 *** General ***
   823 
   824 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   825 and updated, with formally checked references as hyperlinks.
   826 
   827 * Theory loader: use_thy (and similar operations) no longer set the
   828 implicit ML context, which was occasionally hard to predict and in
   829 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   830 provides a proper context already.
   831 
   832 * Theory loader: old-style ML proof scripts being *attached* to a thy
   833 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   834 'use' within a theory file will do the job.
   835 
   836 * Name space merge now observes canonical order, i.e. the second space
   837 is inserted into the first one, while existing entries in the first
   838 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   839 swap theory imports.
   840 
   841 * Syntax: symbol \<chi> is now considered a letter.  Potential
   842 INCOMPATIBILITY in identifier syntax etc.
   843 
   844 * Outer syntax: string tokens no longer admit escaped white space,
   845 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   846 white space without escapes.
   847 
   848 * Outer syntax: string tokens may contain arbitrary character codes
   849 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   850 "foo_bar".
   851 
   852 
   853 *** Pure ***
   854 
   855 * Context-dependent token translations.  Default setup reverts locally
   856 fixed variables, and adds hilite markup for undeclared frees.
   857 
   858 * Unused theorems can be found using the new command 'unused_thms'.
   859 There are three ways of invoking it:
   860 
   861 (1) unused_thms
   862      Only finds unused theorems in the current theory.
   863 
   864 (2) unused_thms thy_1 ... thy_n -
   865      Finds unused theorems in the current theory and all of its ancestors,
   866      excluding the theories thy_1 ... thy_n and all of their ancestors.
   867 
   868 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   869      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   870      their ancestors, excluding the theories thy_1 ... thy_n and all of
   871      their ancestors.
   872 
   873 In order to increase the readability of the list produced by
   874 unused_thms, theorems that have been created by a particular instance
   875 of a theory command such as 'inductive' or 'function' are considered
   876 to belong to the same "group", meaning that if at least one theorem in
   877 this group is used, the other theorems in the same group are no longer
   878 reported as unused.  Moreover, if all theorems in the group are
   879 unused, only one theorem in the group is displayed.
   880 
   881 Note that proof objects have to be switched on in order for
   882 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   883 usually the case when using Proof General with the default settings).
   884 
   885 * Authentic naming of facts disallows ad-hoc overwriting of previous
   886 theorems within the same name space.  INCOMPATIBILITY, need to remove
   887 duplicate fact bindings, or even accidental fact duplications.  Note
   888 that tools may maintain dynamically scoped facts systematically, using
   889 PureThy.add_thms_dynamic.
   890 
   891 * Command 'hide' now allows to hide from "fact" name space as well.
   892 
   893 * Eliminated destructive theorem database, simpset, claset, and
   894 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   895 update of theories within ML code.
   896 
   897 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   898 INCOMPATIBILITY, object-logics depending on former Pure require
   899 additional setup PureThy.old_appl_syntax_setup; object-logics
   900 depending on former CPure need to refer to Pure.
   901 
   902 * Commands 'use' and 'ML' are now purely functional, operating on
   903 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   904 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   905 INCOMPATIBILITY.
   906 
   907 * Command 'setup': discontinued implicit version with ML reference.
   908 
   909 * Instantiation target allows for simultaneous specification of class
   910 instance operations together with an instantiation proof.
   911 Type-checking phase allows to refer to class operations uniformly.
   912 See src/HOL/Complex/Complex.thy for an Isar example and
   913 src/HOL/Library/Eval.thy for an ML example.
   914 
   915 * Indexing of literal facts: be more serious about including only
   916 facts from the visible specification/proof context, but not the
   917 background context (locale etc.).  Affects `prop` notation and method
   918 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   919 situations.
   920 
   921 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   922 "(open)" option, which used to expose internal bound variables to the
   923 proof text.
   924 
   925 * Isar statements: removed obsolete case "rule_context".
   926 INCOMPATIBILITY, better use explicit fixes/assumes.
   927 
   928 * Locale proofs: default proof step now includes 'unfold_locales';
   929 hence 'proof' without argument may be used to unfold locale
   930 predicates.
   931 
   932 
   933 *** Document preparation ***
   934 
   935 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   936 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   937 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   938 spot); renamed link color from "darkblue" to "linkcolor" (default
   939 value unchanged, can be redefined via \definecolor); no longer sets
   940 "a4paper" option (unnecessary or even intrusive).
   941 
   942 * Antiquotation @{lemma A method} proves proposition A by the given
   943 method (either a method name or a method name plus (optional) method
   944 arguments in parentheses) and prints A just like @{prop A}.
   945 
   946 
   947 *** HOL ***
   948 
   949 * New primrec package.  Specification syntax conforms in style to
   950 definition/function/....  No separate induction rule is provided.  The
   951 "primrec" command distinguishes old-style and new-style specifications
   952 by syntax.  The former primrec package is now named OldPrimrecPackage.
   953 When adjusting theories, beware: constants stemming from new-style
   954 primrec specifications have authentic syntax.
   955 
   956 * Metis prover is now an order of magnitude faster, and also works
   957 with multithreading.
   958 
   959 * Metis: the maximum number of clauses that can be produced from a
   960 theorem is now given by the attribute max_clauses.  Theorems that
   961 exceed this number are ignored, with a warning printed.
   962 
   963 * Sledgehammer no longer produces structured proofs by default. To
   964 enable, declare [[sledgehammer_full = true]].  Attributes
   965 reconstruction_modulus, reconstruction_sorts renamed
   966 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   967 
   968 * Method "induct_scheme" derives user-specified induction rules
   969 from well-founded induction and completeness of patterns. This factors
   970 out some operations that are done internally by the function package
   971 and makes them available separately.  See
   972 src/HOL/ex/Induction_Scheme.thy for examples.
   973 
   974 * More flexible generation of measure functions for termination
   975 proofs: Measure functions can be declared by proving a rule of the
   976 form "is_measure f" and giving it the [measure_function] attribute.
   977 The "is_measure" predicate is logically meaningless (always true), and
   978 just guides the heuristic.  To find suitable measure functions, the
   979 termination prover sets up the goal "is_measure ?f" of the appropriate
   980 type and generates all solutions by prolog-style backwards proof using
   981 the declared rules.
   982 
   983 This setup also deals with rules like 
   984 
   985   "is_measure f ==> is_measure (list_size f)"
   986 
   987 which accommodates nested datatypes that recurse through lists.
   988 Similar rules are predeclared for products and option types.
   989 
   990 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   991 
   992   INCOMPATIBILITIES:
   993 
   994   - Definitions of overloaded constants on sets have to be replaced by
   995     definitions on => and bool.
   996 
   997   - Some definitions of overloaded operators on sets can now be proved
   998     using the definitions of the operators on => and bool.  Therefore,
   999     the following theorems have been renamed:
  1000 
  1001       subset_def   -> subset_eq
  1002       psubset_def  -> psubset_eq
  1003       set_diff_def -> set_diff_eq
  1004       Compl_def    -> Compl_eq
  1005       Sup_set_def  -> Sup_set_eq
  1006       Inf_set_def  -> Inf_set_eq
  1007       sup_set_def  -> sup_set_eq
  1008       inf_set_def  -> inf_set_eq
  1009 
  1010   - Due to the incompleteness of the HO unification algorithm, some
  1011     rules such as subst may require manual instantiation, if some of
  1012     the unknowns in the rule is a set.
  1013 
  1014   - Higher order unification and forward proofs:
  1015     The proof pattern
  1016 
  1017       have "P (S::'a set)" <...>
  1018       then have "EX S. P S" ..
  1019 
  1020     no longer works (due to the incompleteness of the HO unification
  1021     algorithm) and must be replaced by the pattern
  1022 
  1023       have "EX S. P S"
  1024       proof
  1025         show "P S" <...>
  1026       qed
  1027 
  1028   - Calculational reasoning with subst (or similar rules):
  1029     The proof pattern
  1030 
  1031       have "P (S::'a set)" <...>
  1032       also have "S = T" <...>
  1033       finally have "P T" .
  1034 
  1035     no longer works (for similar reasons as the previous example) and
  1036     must be replaced by something like
  1037 
  1038       have "P (S::'a set)" <...>
  1039       moreover have "S = T" <...>
  1040       ultimately have "P T" by simp
  1041 
  1042   - Tactics or packages written in ML code:
  1043     Code performing pattern matching on types via
  1044 
  1045       Type ("set", [T]) => ...
  1046 
  1047     must be rewritten. Moreover, functions like strip_type or
  1048     binder_types no longer return the right value when applied to a
  1049     type of the form
  1050 
  1051       T1 => ... => Tn => U => bool
  1052 
  1053     rather than
  1054 
  1055       T1 => ... => Tn => U set
  1056 
  1057 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1058 Wellfounded_Relations to theory Wellfounded.
  1059 
  1060 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1061 
  1062 * Class finite no longer treats UNIV as class parameter.  Use class
  1063 enum from theory Library/Enum instead to achieve a similar effect.
  1064 INCOMPATIBILITY.
  1065 
  1066 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1067 and "Cons".  INCOMPATIBILITY.
  1068 
  1069 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1070 Potential INCOMPATIBILITY.
  1071 
  1072 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1073 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1074 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1075 
  1076 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1077 the same name in theory Orderings:
  1078 
  1079   less_trans
  1080   less_linear
  1081   le_imp_less_or_eq
  1082   le_less_trans
  1083   less_le_trans
  1084   less_not_sym
  1085   less_asym
  1086 
  1087 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1088 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1089 and different variable names.
  1090 
  1091 * Library/Option_ord.thy: Canonical order on option type.
  1092 
  1093 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1094 finite maps.
  1095 
  1096 * Library/Countable.thy: Type class for countable types.
  1097 
  1098 * Theory Int: The representation of numerals has changed.  The infix
  1099 operator BIT and the bit datatype with constructors B0 and B1 have
  1100 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1101 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1102 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1103 accordingly.
  1104 
  1105 * Theory Nat: definition of <= and < on natural numbers no longer
  1106 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1107 le_def and less_def have disappeared.  Consider lemmas not_less
  1108 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1109 
  1110 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1111 (whose purpose mainly is for various fold_set functionals) have been
  1112 abandoned in favor of the existing algebraic classes
  1113 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1114 lower_semilattice (resp. upper_semilattice) and linorder.
  1115 INCOMPATIBILITY.
  1116 
  1117 * Theory Transitive_Closure: induct and cases rules now declare proper
  1118 case_names ("base" and "step").  INCOMPATIBILITY.
  1119 
  1120 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1121 lattices.  The form set-specific version is available as
  1122 Inductive.lfp_ordinal_induct_set.
  1123 
  1124 * Renamed theorems "power.simps" to "power_int.simps".
  1125 INCOMPATIBILITY.
  1126 
  1127 * Class semiring_div provides basic abstract properties of semirings
  1128 with division and modulo operations.  Subsumes former class dvd_mod.
  1129 
  1130 * Merged theories IntDef, Numeral and IntArith into unified theory
  1131 Int.  INCOMPATIBILITY.
  1132 
  1133 * Theory Library/Code_Index: type "index" now represents natural
  1134 numbers rather than integers.  INCOMPATIBILITY.
  1135 
  1136 * New class "uminus" with operation "uminus" (split of from class
  1137 "minus" which now only has operation "minus", binary).
  1138 INCOMPATIBILITY.
  1139 
  1140 * Constants "card", "internal_split", "option_map" now with authentic
  1141 syntax.  INCOMPATIBILITY.
  1142 
  1143 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1144 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1145 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1146 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1147 Sup_set_def, le_def, less_def, option_map_def now with object
  1148 equality.  INCOMPATIBILITY.
  1149 
  1150 * Records. Removed K_record, and replaced it by pure lambda term
  1151 %x. c. The simplifier setup is now more robust against eta expansion.
  1152 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1153 
  1154 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1155 
  1156 * Library/ListVector: new theory of arithmetic vector operations.
  1157 
  1158 * Library/Order_Relation: new theory of various orderings as sets of
  1159 pairs.  Defines preorders, partial orders, linear orders and
  1160 well-orders on sets and on types.
  1161 
  1162 
  1163 *** ZF ***
  1164 
  1165 * Renamed some theories to allow to loading both ZF and HOL in the
  1166 same session:
  1167 
  1168   Datatype  -> Datatype_ZF
  1169   Inductive -> Inductive_ZF
  1170   Int       -> Int_ZF
  1171   IntDiv    -> IntDiv_ZF
  1172   Nat       -> Nat_ZF
  1173   List      -> List_ZF
  1174   Main      -> Main_ZF
  1175 
  1176 INCOMPATIBILITY: ZF theories that import individual theories below
  1177 Main might need to be adapted.  Regular theory Main is still
  1178 available, as trivial extension of Main_ZF.
  1179 
  1180 
  1181 *** ML ***
  1182 
  1183 * ML within Isar: antiquotation @{const name} or @{const
  1184 name(typargs)} produces statically-checked Const term.
  1185 
  1186 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1187 (of the same name).  Removed obsolete print command.
  1188 
  1189 * Removed obsolete "use_legacy_bindings" function.
  1190 
  1191 * The ``print mode'' is now a thread-local value derived from a global
  1192 template (the former print_mode reference), thus access becomes
  1193 non-critical.  The global print_mode reference is for session
  1194 management only; user-code should use print_mode_value,
  1195 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1196 
  1197 * Functions system/system_out provide a robust way to invoke external
  1198 shell commands, with propagation of interrupts (requires Poly/ML
  1199 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1200 
  1201 
  1202 *** System ***
  1203 
  1204 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1205 in accordance with Proof General 3.7, which prefers GNU emacs.
  1206 
  1207 * isatool tty runs Isabelle process with plain tty interaction;
  1208 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1209 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1210 
  1211 * isatool browser now works with Cygwin as well, using general
  1212 "javapath" function defined in Isabelle process environment.
  1213 
  1214 * YXML notation provides a simple and efficient alternative to
  1215 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1216 isatool yxml as described in the Isabelle system manual.
  1217 
  1218 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1219 provides general wrapper for managing an Isabelle process in a robust
  1220 fashion, with ``cooked'' output from stdin/stderr.
  1221 
  1222 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1223 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1224 
  1225 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1226 way of changing the user's settings is via
  1227 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1228 script.
  1229 
  1230 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1231 cores of the underlying machine, which is a good starting point for
  1232 optimal performance tuning.  The corresponding usedir option -M allows
  1233 "max" as an alias for "0".  WARNING: does not work on certain versions
  1234 of Mac OS (with Poly/ML 5.1).
  1235 
  1236 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1237 adverse effect of Isabelle flooding interactive front-ends (notably
  1238 ProofGeneral / XEmacs).
  1239 
  1240 
  1241 
  1242 New in Isabelle2007 (November 2007)
  1243 -----------------------------------
  1244 
  1245 *** General ***
  1246 
  1247 * More uniform information about legacy features, notably a
  1248 warning/error of "Legacy feature: ...", depending on the state of the
  1249 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1250 legacy features will disappear eventually.
  1251 
  1252 * Theory syntax: the header format ``theory A = B + C:'' has been
  1253 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1254 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1255 
  1256 * Theory syntax: the old non-Isar theory file format has been
  1257 discontinued altogether.  Note that ML proof scripts may still be used
  1258 with Isar theories; migration is usually quite simple with the ML
  1259 function use_legacy_bindings.  INCOMPATIBILITY.
  1260 
  1261 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1262 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1263 quotes.
  1264 
  1265 * Theory loader: be more serious about observing the static theory
  1266 header specifications (including optional directories), but not the
  1267 accidental file locations of previously successful loads.  The strict
  1268 update policy of former update_thy is now already performed by
  1269 use_thy, so the former has been removed; use_thys updates several
  1270 theories simultaneously, just as 'imports' within a theory header
  1271 specification, but without merging the results.  Potential
  1272 INCOMPATIBILITY: may need to refine theory headers and commands
  1273 ROOT.ML which depend on load order.
  1274 
  1275 * Theory loader: optional support for content-based file
  1276 identification, instead of the traditional scheme of full physical
  1277 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1278 (cf. the system manual).  The new scheme allows to work with
  1279 non-finished theories in persistent session images, such that source
  1280 files may be moved later on without requiring reloads.
  1281 
  1282 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1283 file (with the same base name as the theory) are considered a legacy
  1284 feature, which will disappear eventually. Even now, the theory loader
  1285 no longer maintains dependencies on such files.
  1286 
  1287 * Syntax: the scope for resolving ambiguities via type-inference is
  1288 now limited to individual terms, instead of whole simultaneous
  1289 specifications as before. This greatly reduces the complexity of the
  1290 syntax module and improves flexibility by separating parsing and
  1291 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1292 'fixes' etc.) are required in rare situations.
  1293 
  1294 * Syntax: constants introduced by new-style packages ('definition',
  1295 'abbreviation' etc.) are passed through the syntax module in
  1296 ``authentic mode''. This means that associated mixfix annotations
  1297 really stick to such constants, independently of potential name space
  1298 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1299 trees are represented slightly differently, may need to adapt syntax
  1300 translations accordingly. Use CONST marker in 'translations' and
  1301 @{const_syntax} antiquotation in 'parse_translation' etc.
  1302 
  1303 * Legacy goal package: reduced interface to the bare minimum required
  1304 to keep existing proof scripts running.  Most other user-level
  1305 functions are now part of the OldGoals structure, which is *not* open
  1306 by default (consider isatool expandshort before open OldGoals).
  1307 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1308 these tend to cause confusion about the actual goal (!) context being
  1309 used here, which is not necessarily the same as the_context().
  1310 
  1311 * Command 'find_theorems': supports "*" wild-card in "name:"
  1312 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1313 support a specific search form (see ProofGeneral/CHANGES).
  1314 
  1315 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1316 by default, which means that "prems" (and also "fixed variables") are
  1317 suppressed from proof state output.  Note that the ProofGeneral
  1318 settings mechanism allows to change and save options persistently, but
  1319 older versions of Isabelle will fail to start up if a negative prems
  1320 limit is imposed.
  1321 
  1322 * Local theory targets may be specified by non-nested blocks of
  1323 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1324 contain definitions, theorems etc., including any derived mechanism
  1325 that has been implemented on top of these primitives.  This concept
  1326 generalizes the existing ``theorem (in ...)'' towards more versatility
  1327 and scalability.
  1328 
  1329 * Proof General interface: proper undo of final 'end' command;
  1330 discontinued Isabelle/classic mode (ML proof scripts).
  1331 
  1332 
  1333 *** Document preparation ***
  1334 
  1335 * Added antiquotation @{theory name} which prints the given name,
  1336 after checking that it refers to a valid ancestor theory in the
  1337 current context.
  1338 
  1339 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1340 check the given source text as ML type/structure, printing verbatim.
  1341 
  1342 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1343 "c args == rhs" given in the current context.  (Any number of
  1344 arguments may be given on the LHS.)
  1345 
  1346 
  1347 *** Pure ***
  1348 
  1349 * The 'class' package offers a combination of axclass and locale to
  1350 achieve Haskell-like type classes in Isabelle.  Definitions and
  1351 theorems within a class context produce both relative results (with
  1352 implicit parameters according to the locale context), and polymorphic
  1353 constants with qualified polymorphism (according to the class
  1354 context).  Within the body context of a 'class' target, a separate
  1355 syntax layer ("user space type system") takes care of converting
  1356 between global polymorphic consts and internal locale representation.
  1357 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1358 "isatool doc classes" provides a tutorial.
  1359 
  1360 * Generic code generator framework allows to generate executable
  1361 code for ML and Haskell (including Isabelle classes).  A short usage
  1362 sketch:
  1363 
  1364     internal compilation:
  1365         export_code <list of constants (term syntax)> in SML
  1366     writing SML code to a file:
  1367         export_code <list of constants (term syntax)> in SML <filename>
  1368     writing OCaml code to a file:
  1369         export_code <list of constants (term syntax)> in OCaml <filename>
  1370     writing Haskell code to a bunch of files:
  1371         export_code <list of constants (term syntax)> in Haskell <filename>
  1372 
  1373     evaluating closed propositions to True/False using code generation:
  1374         method ``eval''
  1375 
  1376 Reasonable default setup of framework in HOL.
  1377 
  1378 Theorem attributs for selecting and transforming function equations theorems:
  1379 
  1380     [code fun]:        select a theorem as function equation for a specific constant
  1381     [code fun del]:    deselect a theorem as function equation for a specific constant
  1382     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1383     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1384 
  1385 User-defined serializations (target in {SML, OCaml, Haskell}):
  1386 
  1387     code_const <and-list of constants (term syntax)>
  1388       {(target) <and-list of const target syntax>}+
  1389 
  1390     code_type <and-list of type constructors>
  1391       {(target) <and-list of type target syntax>}+
  1392 
  1393     code_instance <and-list of instances>
  1394       {(target)}+
  1395         where instance ::= <type constructor> :: <class>
  1396 
  1397     code_class <and_list of classes>
  1398       {(target) <and-list of class target syntax>}+
  1399         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1400 
  1401 code_instance and code_class only are effective to target Haskell.
  1402 
  1403 For example usage see src/HOL/ex/Codegenerator.thy and
  1404 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1405 generation from Isabelle/HOL theories is available via "isatool doc
  1406 codegen".
  1407 
  1408 * Code generator: consts in 'consts_code' Isar commands are now
  1409 referred to by usual term syntax (including optional type
  1410 annotations).
  1411 
  1412 * Command 'no_translations' removes translation rules from theory
  1413 syntax.
  1414 
  1415 * Overloaded definitions are now actually checked for acyclic
  1416 dependencies.  The overloading scheme is slightly more general than
  1417 that of Haskell98, although Isabelle does not demand an exact
  1418 correspondence to type class and instance declarations.
  1419 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1420 exotic versions of overloading -- at the discretion of the user!
  1421 
  1422 Polymorphic constants are represented via type arguments, i.e. the
  1423 instantiation that matches an instance against the most general
  1424 declaration given in the signature.  For example, with the declaration
  1425 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1426 as c(nat).  Overloading is essentially simultaneous structural
  1427 recursion over such type arguments.  Incomplete specification patterns
  1428 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1429 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1430 Command 'print_theory' outputs the normalized system of recursive
  1431 equations, see section "definitions".
  1432 
  1433 * Configuration options are maintained within the theory or proof
  1434 context (with name and type bool/int/string), providing a very simple
  1435 interface to a poor-man's version of general context data.  Tools may
  1436 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1437 these values using Config.get etc.  Users may change options via an
  1438 associated attribute of the same name.  This form of context
  1439 declaration works particularly well with commands 'declare' or
  1440 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1441 very easy to avoid global references, which would not observe Isar
  1442 toplevel undo/redo and fail to work with multithreading.
  1443 
  1444 Various global ML references of Pure and HOL have been turned into
  1445 configuration options:
  1446 
  1447   Unify.search_bound		unify_search_bound
  1448   Unify.trace_bound		unify_trace_bound
  1449   Unify.trace_simp		unify_trace_simp
  1450   Unify.trace_types		unify_trace_types
  1451   Simplifier.simp_depth_limit	simp_depth_limit
  1452   Blast.depth_limit		blast_depth_limit
  1453   DatatypeProp.dtK		datatype_distinctness_limit
  1454   fast_arith_neq_limit  	fast_arith_neq_limit
  1455   fast_arith_split_limit	fast_arith_split_limit
  1456 
  1457 * Named collections of theorems may be easily installed as context
  1458 data using the functor NamedThmsFun (see also
  1459 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1460 attributes; there is also a toplevel print command.  This facility is
  1461 just a common case of general context data, which is the preferred way
  1462 for anything more complex than just a list of facts in canonical
  1463 order.
  1464 
  1465 * Isar: command 'declaration' augments a local theory by generic
  1466 declaration functions written in ML.  This enables arbitrary content
  1467 being added to the context, depending on a morphism that tells the
  1468 difference of the original declaration context wrt. the application
  1469 context encountered later on.
  1470 
  1471 * Isar: proper interfaces for simplification procedures.  Command
  1472 'simproc_setup' declares named simprocs (with match patterns, and body
  1473 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1474 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1475 
  1476 * Isar: an extra pair of brackets around attribute declarations
  1477 abbreviates a theorem reference involving an internal dummy fact,
  1478 which will be ignored later --- only the effect of the attribute on
  1479 the background context will persist.  This form of in-place
  1480 declarations is particularly useful with commands like 'declare' and
  1481 'using', for example ``have A using [[simproc a]] by simp''.
  1482 
  1483 * Isar: method "assumption" (and implicit closing of subproofs) now
  1484 takes simple non-atomic goal assumptions into account: after applying
  1485 an assumption as a rule the resulting subgoals are solved by atomic
  1486 assumption steps.  This is particularly useful to finish 'obtain'
  1487 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1488 without referring to the original premise "!!x. P x ==> thesis" in the
  1489 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1490 more permissive.
  1491 
  1492 * Isar: implicit use of prems from the Isar proof context is
  1493 considered a legacy feature.  Common applications like ``have A .''
  1494 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1495 referencing facts explicitly here improves readability and
  1496 maintainability of proof texts.
  1497 
  1498 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1499 the obtained context from the course of reasoning!  For example:
  1500 
  1501   assume "EX x y. A x & B y"   -- "any previous fact"
  1502   then guess x and y by clarify
  1503 
  1504 This technique is potentially adventurous, depending on the facts and
  1505 proof tools being involved here.
  1506 
  1507 * Isar: known facts from the proof context may be specified as literal
  1508 propositions, using ASCII back-quote syntax.  This works wherever
  1509 named facts used to be allowed so far, in proof commands, proof
  1510 methods, attributes etc.  Literal facts are retrieved from the context
  1511 according to unification of type and term parameters.  For example,
  1512 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1513 theorems in the current context, then these are valid literal facts:
  1514 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1515 
  1516 There is also a proof method "fact" which does the same composition
  1517 for explicit goal states, e.g. the following proof texts coincide with
  1518 certain special cases of literal facts:
  1519 
  1520   have "A" by fact                 ==  note `A`
  1521   have "A ==> B" by fact           ==  note `A ==> B`
  1522   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1523   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1524 
  1525 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1526 outer syntax.  Thus symbolic identifiers may be used without
  1527 additional white space in declarations like this: ``assume *: A''.
  1528 
  1529 * Isar: 'print_facts' prints all local facts of the current context,
  1530 both named and unnamed ones.
  1531 
  1532 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1533 
  1534   def x == "t" and y == "u"
  1535 
  1536 * Isar: added command 'unfolding', which is structurally similar to
  1537 'using', but affects both the goal state and facts by unfolding given
  1538 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1539 'unfolded' attribute may be replaced by first-class proof text.
  1540 
  1541 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1542 and command 'unfolding' now all support object-level equalities
  1543 (potentially conditional).  The underlying notion of rewrite rule is
  1544 analogous to the 'rule_format' attribute, but *not* that of the
  1545 Simplifier (which is usually more generous).
  1546 
  1547 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1548 premises of a theorem by n. Useful in conjunction with drule.
  1549 
  1550 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1551 method expression within a sandbox consisting of the first N
  1552 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1553 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1554 simplifies all new goals that emerge from applying rule foo to the
  1555 originally first one.
  1556 
  1557 * Isar: schematic goals are no longer restricted to higher-order
  1558 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1559 expected.
  1560 
  1561 * Isar: the conclusion of a long theorem statement is now either
  1562 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1563 (essentially a disjunction of cases with local parameters and
  1564 assumptions).  The latter allows to express general elimination rules
  1565 adequately; in this notation common elimination rules look like this:
  1566 
  1567   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1568     assumes "EX x. P x"
  1569     obtains x where "P x"
  1570 
  1571   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1572     assumes "A & B"
  1573     obtains A and B
  1574 
  1575   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1576     assumes "A | B"
  1577     obtains
  1578       A
  1579     | B
  1580 
  1581 The subsequent classical rules even refer to the formal "thesis"
  1582 explicitly:
  1583 
  1584   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1585     obtains "~ thesis"
  1586 
  1587   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1588     obtains "thesis ==> something"
  1589 
  1590 The actual proof of an 'obtains' statement is analogous to that of the
  1591 Isar proof element 'obtain', only that there may be several cases.
  1592 Optional case names may be specified in parentheses; these will be
  1593 available both in the present proof and as annotations in the
  1594 resulting rule, for later use with the 'cases' method (cf. attribute
  1595 case_names).
  1596 
  1597 * Isar: the assumptions of a long theorem statement are available as
  1598 "assms" fact in the proof context.  This is more appropriate than the
  1599 (historical) "prems", which refers to all assumptions of the current
  1600 context, including those from the target locale, proof body etc.
  1601 
  1602 * Isar: 'print_statement' prints theorems from the current theory or
  1603 proof context in long statement form, according to the syntax of a
  1604 top-level lemma.
  1605 
  1606 * Isar: 'obtain' takes an optional case name for the local context
  1607 introduction rule (default "that").
  1608 
  1609 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1610 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1611 to occur.
  1612 
  1613 * Pure: syntax "CONST name" produces a fully internalized constant
  1614 according to the current context.  This is particularly useful for
  1615 syntax translations that should refer to internal constant
  1616 representations independently of name spaces.
  1617 
  1618 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1619 instead of "FOO ". This allows multiple binder declarations to coexist
  1620 in the same context.  INCOMPATIBILITY.
  1621 
  1622 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1623 primitive that also works in a locale context (both for constants and
  1624 fixed variables). Type declaration and internal syntactic representation
  1625 of given constants retrieved from the context. Likewise, the
  1626 'no_notation' command allows to remove given syntax annotations from the
  1627 current context.
  1628 
  1629 * Isar/locales: new derived specification elements 'axiomatization',
  1630 'definition', 'abbreviation', which support type-inference, admit
  1631 object-level specifications (equality, equivalence).  See also the
  1632 isar-ref manual.  Examples:
  1633 
  1634   axiomatization
  1635     eq  (infix "===" 50) where
  1636     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1637 
  1638   definition "f x y = x + y + 1"
  1639   definition g where "g x = f x x"
  1640 
  1641   abbreviation
  1642     neq  (infix "=!=" 50) where
  1643     "x =!= y == ~ (x === y)"
  1644 
  1645 These specifications may be also used in a locale context.  Then the
  1646 constants being introduced depend on certain fixed parameters, and the
  1647 constant name is qualified by the locale base name.  An internal
  1648 abbreviation takes care for convenient input and output, making the
  1649 parameters implicit and using the original short name.  See also
  1650 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1651 entities from a monomorphic theory.
  1652 
  1653 Presently, abbreviations are only available 'in' a target locale, but
  1654 not inherited by general import expressions.  Also note that
  1655 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1656 'translations' in common applications.  The "no_abbrevs" print mode
  1657 prevents folding of abbreviations in term output.
  1658 
  1659 Concrete syntax is attached to specified constants in internal form,
  1660 independently of name spaces.  The parse tree representation is
  1661 slightly different -- use 'notation' instead of raw 'syntax', and
  1662 'translations' with explicit "CONST" markup to accommodate this.
  1663 
  1664 * Pure/Isar: unified syntax for new-style specification mechanisms
  1665 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1666 full type inference and dummy patterns ("_").  For example:
  1667 
  1668   definition "K x _ = x"
  1669 
  1670   inductive conj for A B
  1671   where "A ==> B ==> conj A B"
  1672 
  1673 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1674 the current context.  Print mode "no_abbrevs" prevents inversion of
  1675 abbreviations on output.
  1676 
  1677 * Isar/locales: improved parameter handling: use of locales "var" and
  1678 "struct" no longer necessary; - parameter renamings are no longer
  1679 required to be injective.  For example, this allows to define
  1680 endomorphisms as locale endom = homom mult mult h.
  1681 
  1682 * Isar/locales: changed the way locales with predicates are defined.
  1683 Instead of accumulating the specification, the imported expression is
  1684 now an interpretation.  INCOMPATIBILITY: different normal form of
  1685 locale expressions.  In particular, in interpretations of locales with
  1686 predicates, goals repesenting already interpreted fragments are not
  1687 removed automatically.  Use methods `intro_locales' and
  1688 `unfold_locales'; see below.
  1689 
  1690 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1691 provide backward reasoning on locales predicates.  The methods are
  1692 aware of interpretations and discharge corresponding goals.
  1693 `intro_locales' is less aggressive then `unfold_locales' and does not
  1694 unfold predicates to assumptions.
  1695 
  1696 * Isar/locales: the order in which locale fragments are accumulated
  1697 has changed.  This enables to override declarations from fragments due
  1698 to interpretations -- for example, unwanted simp rules.
  1699 
  1700 * Isar/locales: interpretation in theories and proof contexts has been
  1701 extended.  One may now specify (and prove) equations, which are
  1702 unfolded in interpreted theorems.  This is useful for replacing
  1703 defined concepts (constants depending on locale parameters) by
  1704 concepts already existing in the target context.  Example:
  1705 
  1706   interpretation partial_order ["op <= :: [int, int] => bool"]
  1707     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1708 
  1709 Typically, the constant `partial_order.less' is created by a
  1710 definition specification element in the context of locale
  1711 partial_order.
  1712 
  1713 * Method "induct": improved internal context management to support
  1714 local fixes and defines on-the-fly. Thus explicit meta-level
  1715 connectives !!  and ==> are rarely required anymore in inductive goals
  1716 (using object-logic connectives for this purpose has been long
  1717 obsolete anyway). Common proof patterns are explained in
  1718 src/HOL/Induct/Common_Patterns.thy, see also
  1719 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1720 examples.
  1721 
  1722 * Method "induct": improved handling of simultaneous goals. Instead of
  1723 introducing object-level conjunction, the statement is now split into
  1724 several conclusions, while the corresponding symbolic cases are nested
  1725 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1726 see src/HOL/Induct/Common_Patterns.thy, for example.
  1727 
  1728 * Method "induct": mutual induction rules are now specified as a list
  1729 of rule sharing the same induction cases. HOL packages usually provide
  1730 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1731 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1732 mutual induction rules differently, i.e. like this:
  1733 
  1734   (induct rule: foo_bar.inducts)
  1735   (induct set: foo bar)
  1736   (induct pred: foo bar)
  1737   (induct type: foo bar)
  1738 
  1739 The ML function ProjectRule.projections turns old-style rules into the
  1740 new format.
  1741 
  1742 * Method "coinduct": dual of induction, see
  1743 src/HOL/Library/Coinductive_List.thy for various examples.
  1744 
  1745 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1746 considered a legacy feature.
  1747 
  1748 * Attribute "symmetric" produces result with standardized schematic
  1749 variables (index 0).  Potential INCOMPATIBILITY.
  1750 
  1751 * Simplifier: by default the simplifier trace only shows top level
  1752 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1753 default. Thus there is less danger of being flooded by the trace. The
  1754 trace indicates where parts have been suppressed.
  1755   
  1756 * Provers/classical: removed obsolete classical version of elim_format
  1757 attribute; classical elim/dest rules are now treated uniformly when
  1758 manipulating the claset.
  1759 
  1760 * Provers/classical: stricter checks to ensure that supplied intro,
  1761 dest and elim rules are well-formed; dest and elim rules must have at
  1762 least one premise.
  1763 
  1764 * Provers/classical: attributes dest/elim/intro take an optional
  1765 weight argument for the rule (just as the Pure versions).  Weights are
  1766 ignored by automated tools, but determine the search order of single
  1767 rule steps.
  1768 
  1769 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1770 where the body does not mention the bound variable.  Note that dummy
  1771 patterns implicitly depend on their context of bounds, which makes
  1772 "{_. _}" match any set comprehension as expected.  Potential
  1773 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1774 constant "_idtdummy" in the binding position.
  1775 
  1776 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1777 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1778 for example "A -> B" => "Pi A (%_. B)".
  1779 
  1780 * Pure: 'class_deps' command visualizes the subclass relation, using
  1781 the graph browser tool.
  1782 
  1783 * Pure: 'print_theory' now suppresses certain internal declarations by
  1784 default; use '!' option for full details.
  1785 
  1786 
  1787 *** HOL ***
  1788 
  1789 * Method "metis" proves goals by applying the Metis general-purpose
  1790 resolution prover (see also http://gilith.com/software/metis/).
  1791 Examples are in the directory MetisExamples.  WARNING: the
  1792 Isabelle/HOL-Metis integration does not yet work properly with
  1793 multi-threading.
  1794   
  1795 * Command 'sledgehammer' invokes external automatic theorem provers as
  1796 background processes.  It generates calls to the "metis" method if
  1797 successful. These can be pasted into the proof.  Users do not have to
  1798 wait for the automatic provers to return.  WARNING: does not really
  1799 work with multi-threading.
  1800 
  1801 * New "auto_quickcheck" feature tests outermost goal statements for
  1802 potential counter-examples.  Controlled by ML references
  1803 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1804 5000 milliseconds).  Fails silently if statements is outside of
  1805 executable fragment, or any other codgenerator problem occurs.
  1806 
  1807 * New constant "undefined" with axiom "undefined x = undefined".
  1808 
  1809 * Added class "HOL.eq", allowing for code generation with polymorphic
  1810 equality.
  1811 
  1812 * Some renaming of class constants due to canonical name prefixing in
  1813 the new 'class' package:
  1814 
  1815     HOL.abs ~> HOL.abs_class.abs
  1816     HOL.divide ~> HOL.divide_class.divide
  1817     0 ~> HOL.zero_class.zero
  1818     1 ~> HOL.one_class.one
  1819     op + ~> HOL.plus_class.plus
  1820     op - ~> HOL.minus_class.minus
  1821     uminus ~> HOL.minus_class.uminus
  1822     op * ~> HOL.times_class.times
  1823     op < ~> HOL.ord_class.less
  1824     op <= > HOL.ord_class.less_eq
  1825     Nat.power ~> Power.power_class.power
  1826     Nat.size ~> Nat.size_class.size
  1827     Numeral.number_of ~> Numeral.number_class.number_of
  1828     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1829     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1830     Orderings.min ~> Orderings.ord_class.min
  1831     Orderings.max ~> Orderings.ord_class.max
  1832     Divides.op div ~> Divides.div_class.div
  1833     Divides.op mod ~> Divides.div_class.mod
  1834     Divides.op dvd ~> Divides.div_class.dvd
  1835 
  1836 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1837 
  1838 a) User-defined constants using any of the names "plus", "minus",
  1839 "times", "less" or "less_eq". The standard syntax translations for
  1840 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1841 names.
  1842 
  1843 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1844 INCOMPATIBILITY: use more specific names.
  1845 
  1846 c) Permutative equations (e.g. "a + b = b + a")
  1847 Since the change of names also changes the order of terms, permutative
  1848 rewrite rules may get applied in a different order. Experience shows
  1849 that this is rarely the case (only two adaptions in the whole Isabelle
  1850 distribution).  INCOMPATIBILITY: rewrite proofs
  1851 
  1852 d) ML code directly refering to constant names
  1853 This in general only affects hand-written proof tactics, simprocs and
  1854 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1855 Consider using @{const_name} antiquotation.
  1856 
  1857 * New class "default" with associated constant "default".
  1858 
  1859 * Function "sgn" is now overloaded and available on int, real, complex
  1860 (and other numeric types), using class "sgn".  Two possible defs of
  1861 sgn are given as equational assumptions in the classes sgn_if and
  1862 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1863 INCOMPATIBILITY.
  1864 
  1865 * Locale "partial_order" now unified with class "order" (cf. theory
  1866 Orderings), added parameter "less".  INCOMPATIBILITY.
  1867 
  1868 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1869 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1870 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1871 
  1872 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1873 changed order of proof goals in instance proofs.
  1874 
  1875 * The transitivity reasoner for partial and linear orders is set up
  1876 for classes "order" and "linorder".  Instances of the reasoner are available
  1877 in all contexts importing or interpreting the corresponding locales.
  1878 Method "order" invokes the reasoner separately; the reasoner
  1879 is also integrated with the Simplifier as a solver.  Diagnostic
  1880 command 'print_orders' shows the available instances of the reasoner
  1881 in the current context.
  1882 
  1883 * Localized monotonicity predicate in theory "Orderings"; integrated
  1884 lemmas max_of_mono and min_of_mono with this predicate.
  1885 INCOMPATIBILITY.
  1886 
  1887 * Formulation of theorem "dense" changed slightly due to integration
  1888 with new class dense_linear_order.
  1889 
  1890 * Uniform lattice theory development in HOL.
  1891 
  1892     constants "meet" and "join" now named "inf" and "sup"
  1893     constant "Meet" now named "Inf"
  1894 
  1895     classes "meet_semilorder" and "join_semilorder" now named
  1896       "lower_semilattice" and "upper_semilattice"
  1897     class "lorder" now named "lattice"
  1898     class "comp_lat" now named "complete_lattice"
  1899 
  1900     Instantiation of lattice classes allows explicit definitions
  1901     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1902 
  1903   INCOMPATIBILITY.  Theorem renames:
  1904 
  1905     meet_left_le            ~> inf_le1
  1906     meet_right_le           ~> inf_le2
  1907     join_left_le            ~> sup_ge1
  1908     join_right_le           ~> sup_ge2
  1909     meet_join_le            ~> inf_sup_ord
  1910     le_meetI                ~> le_infI
  1911     join_leI                ~> le_supI
  1912     le_meet                 ~> le_inf_iff
  1913     le_join                 ~> ge_sup_conv
  1914     meet_idempotent         ~> inf_idem
  1915     join_idempotent         ~> sup_idem
  1916     meet_comm               ~> inf_commute
  1917     join_comm               ~> sup_commute
  1918     meet_leI1               ~> le_infI1
  1919     meet_leI2               ~> le_infI2
  1920     le_joinI1               ~> le_supI1
  1921     le_joinI2               ~> le_supI2
  1922     meet_assoc              ~> inf_assoc
  1923     join_assoc              ~> sup_assoc
  1924     meet_left_comm          ~> inf_left_commute
  1925     meet_left_idempotent    ~> inf_left_idem
  1926     join_left_comm          ~> sup_left_commute
  1927     join_left_idempotent    ~> sup_left_idem
  1928     meet_aci                ~> inf_aci
  1929     join_aci                ~> sup_aci
  1930     le_def_meet             ~> le_iff_inf
  1931     le_def_join             ~> le_iff_sup
  1932     join_absorp2            ~> sup_absorb2
  1933     join_absorp1            ~> sup_absorb1
  1934     meet_absorp1            ~> inf_absorb1
  1935     meet_absorp2            ~> inf_absorb2
  1936     meet_join_absorp        ~> inf_sup_absorb
  1937     join_meet_absorp        ~> sup_inf_absorb
  1938     distrib_join_le         ~> distrib_sup_le
  1939     distrib_meet_le         ~> distrib_inf_le
  1940 
  1941     add_meet_distrib_left   ~> add_inf_distrib_left
  1942     add_join_distrib_left   ~> add_sup_distrib_left
  1943     is_join_neg_meet        ~> is_join_neg_inf
  1944     is_meet_neg_join        ~> is_meet_neg_sup
  1945     add_meet_distrib_right  ~> add_inf_distrib_right
  1946     add_join_distrib_right  ~> add_sup_distrib_right
  1947     add_meet_join_distribs  ~> add_sup_inf_distribs
  1948     join_eq_neg_meet        ~> sup_eq_neg_inf
  1949     meet_eq_neg_join        ~> inf_eq_neg_sup
  1950     add_eq_meet_join        ~> add_eq_inf_sup
  1951     meet_0_imp_0            ~> inf_0_imp_0
  1952     join_0_imp_0            ~> sup_0_imp_0
  1953     meet_0_eq_0             ~> inf_0_eq_0
  1954     join_0_eq_0             ~> sup_0_eq_0
  1955     neg_meet_eq_join        ~> neg_inf_eq_sup
  1956     neg_join_eq_meet        ~> neg_sup_eq_inf
  1957     join_eq_if              ~> sup_eq_if
  1958 
  1959     mono_meet               ~> mono_inf
  1960     mono_join               ~> mono_sup
  1961     meet_bool_eq            ~> inf_bool_eq
  1962     join_bool_eq            ~> sup_bool_eq
  1963     meet_fun_eq             ~> inf_fun_eq
  1964     join_fun_eq             ~> sup_fun_eq
  1965     meet_set_eq             ~> inf_set_eq
  1966     join_set_eq             ~> sup_set_eq
  1967     meet1_iff               ~> inf1_iff
  1968     meet2_iff               ~> inf2_iff
  1969     meet1I                  ~> inf1I
  1970     meet2I                  ~> inf2I
  1971     meet1D1                 ~> inf1D1
  1972     meet2D1                 ~> inf2D1
  1973     meet1D2                 ~> inf1D2
  1974     meet2D2                 ~> inf2D2
  1975     meet1E                  ~> inf1E
  1976     meet2E                  ~> inf2E
  1977     join1_iff               ~> sup1_iff
  1978     join2_iff               ~> sup2_iff
  1979     join1I1                 ~> sup1I1
  1980     join2I1                 ~> sup2I1
  1981     join1I1                 ~> sup1I1
  1982     join2I2                 ~> sup1I2
  1983     join1CI                 ~> sup1CI
  1984     join2CI                 ~> sup2CI
  1985     join1E                  ~> sup1E
  1986     join2E                  ~> sup2E
  1987 
  1988     is_meet_Meet            ~> is_meet_Inf
  1989     Meet_bool_def           ~> Inf_bool_def
  1990     Meet_fun_def            ~> Inf_fun_def
  1991     Meet_greatest           ~> Inf_greatest
  1992     Meet_lower              ~> Inf_lower
  1993     Meet_set_def            ~> Inf_set_def
  1994 
  1995     Sup_def                 ~> Sup_Inf
  1996     Sup_bool_eq             ~> Sup_bool_def
  1997     Sup_fun_eq              ~> Sup_fun_def
  1998     Sup_set_eq              ~> Sup_set_def
  1999 
  2000     listsp_meetI            ~> listsp_infI
  2001     listsp_meet_eq          ~> listsp_inf_eq
  2002 
  2003     meet_min                ~> inf_min
  2004     join_max                ~> sup_max
  2005 
  2006 * Added syntactic class "size"; overloaded constant "size" now has
  2007 type "'a::size ==> bool"
  2008 
  2009 * Internal reorganisation of `size' of datatypes: size theorems
  2010 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2011 simplification rules by default!); theorems "prod.size" now named
  2012 "*.size".
  2013 
  2014 * Class "div" now inherits from class "times" rather than "type".
  2015 INCOMPATIBILITY.
  2016 
  2017 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2018 Linorder etc.  have disappeared; operations defined in terms of
  2019 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2020 
  2021 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2022 
  2023 * HOL-Word: New extensive library and type for generic, fixed size
  2024 machine words, with arithemtic, bit-wise, shifting and rotating
  2025 operations, reflection into int, nat, and bool lists, automation for
  2026 linear arithmetic (by automatic reflection into nat or int), including
  2027 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2028 arithmetic type classes, supporting automatic simplification of
  2029 numerals on all operations.
  2030 
  2031 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2032 
  2033 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2034 
  2035 * Code generator library theories:
  2036   - Code_Integer represents HOL integers by big integer literals in target
  2037     languages.
  2038   - Code_Char represents HOL characters by character literals in target
  2039     languages.
  2040   - Code_Char_chr like Code_Char, but also offers treatment of character
  2041     codes; includes Code_Integer.
  2042   - Executable_Set allows to generate code for finite sets using lists.
  2043   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2044     denominator).
  2045   - Executable_Real implements a subset of real numbers, namly those
  2046     representable by rational numbers.
  2047   - Efficient_Nat implements natural numbers by integers, which in general will
  2048     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2049     includes Code_Integer.
  2050   - Code_Index provides an additional datatype index which is mapped to
  2051     target-language built-in integers.
  2052   - Code_Message provides an additional datatype message_string which is isomorphic to
  2053     strings; messages are mapped to target-language strings.
  2054 
  2055 * New package for inductive predicates
  2056 
  2057   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2058 
  2059     inductive
  2060       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2061       for z_1 :: U_1 and ... and z_n :: U_m
  2062     where
  2063       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2064     | ...
  2065 
  2066   with full support for type-inference, rather than
  2067 
  2068     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2069 
  2070     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2071     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2072 
  2073     inductive "s z_1 ... z_m"
  2074     intros
  2075       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2076       ...
  2077 
  2078   For backward compatibility, there is a wrapper allowing inductive
  2079   sets to be defined with the new package via
  2080 
  2081     inductive_set
  2082       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2083       for z_1 :: U_1 and ... and z_n :: U_m
  2084     where
  2085       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2086     | ...
  2087 
  2088   or
  2089 
  2090     inductive_set
  2091       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2092       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2093       for z_1 :: U_1 and ... and z_n :: U_m
  2094     where
  2095       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2096     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2097     | ...
  2098 
  2099   if the additional syntax "p ..." is required.
  2100 
  2101   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2102   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2103 
  2104   INCOMPATIBILITIES:
  2105 
  2106   - Since declaration and definition of inductive sets or predicates
  2107     is no longer separated, abbreviations involving the newly
  2108     introduced sets or predicates must be specified together with the
  2109     introduction rules after the 'where' keyword (see above), rather
  2110     than before the actual inductive definition.
  2111 
  2112   - The variables in induction and elimination rules are now
  2113     quantified in the order of their occurrence in the introduction
  2114     rules, rather than in alphabetical order. Since this may break
  2115     some proofs, these proofs either have to be repaired, e.g. by
  2116     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2117     statements of the form
  2118 
  2119       case (rule_i a_i_1 ... a_i_{k_i})
  2120 
  2121     or the old order of quantification has to be restored by explicitly adding
  2122     meta-level quantifiers in the introduction rules, i.e.
  2123 
  2124       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2125 
  2126   - The format of the elimination rules is now
  2127 
  2128       p z_1 ... z_m x_1 ... x_n ==>
  2129         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2130         ==> ... ==> P
  2131 
  2132     for predicates and
  2133 
  2134       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2135         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2136         ==> ... ==> P
  2137 
  2138     for sets rather than
  2139 
  2140       x : s z_1 ... z_m ==>
  2141         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2142         ==> ... ==> P
  2143 
  2144     This may require terms in goals to be expanded to n-tuples
  2145     (e.g. using case_tac or simplification with the split_paired_all
  2146     rule) before the above elimination rule is applicable.
  2147 
  2148   - The elimination or case analysis rules for (mutually) inductive
  2149     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2150     list of rules "p_1_..._p_k.elims" is no longer available.
  2151 
  2152 * New package "function"/"fun" for general recursive functions,
  2153 supporting mutual and nested recursion, definitions in local contexts,
  2154 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2155 for small examples, and the separate tutorial on the function
  2156 package. The old recdef "package" is still available as before, but
  2157 users are encouraged to use the new package.
  2158 
  2159 * Method "lexicographic_order" automatically synthesizes termination
  2160 relations as lexicographic combinations of size measures. 
  2161 
  2162 * Case-expressions allow arbitrary constructor-patterns (including
  2163 "_") and take their order into account, like in functional
  2164 programming.  Internally, this is translated into nested
  2165 case-expressions; missing cases are added and mapped to the predefined
  2166 constant "undefined". In complicated cases printing may no longer show
  2167 the original input but the internal form. Lambda-abstractions allow
  2168 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2169 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2170 variable.
  2171 
  2172 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2173 is an abbreviation for "of_nat :: nat => int". The simplification
  2174 rules for "of_nat" have been changed to work like "int" did
  2175 previously.  Potential INCOMPATIBILITY:
  2176   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2177   - of_nat_diff and of_nat_mult are no longer default simp rules
  2178 
  2179 * Method "algebra" solves polynomial equations over (semi)rings using
  2180 Groebner bases. The (semi)ring structure is defined by locales and the
  2181 tool setup depends on that generic context. Installing the method for
  2182 a specific type involves instantiating the locale and possibly adding
  2183 declarations for computation on the coefficients.  The method is
  2184 already instantiated for natural numbers and for the axiomatic class
  2185 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2186 CALCULEMUS 2007 for the general principles underlying this
  2187 architecture of context-aware proof-tools.
  2188 
  2189 * Method "ferrack" implements quantifier elimination over
  2190 special-purpose dense linear orders using locales (analogous to
  2191 "algebra"). The method is already installed for class
  2192 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2193 rat, etc.
  2194 
  2195 * Former constant "List.op @" now named "List.append".  Use ML
  2196 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2197 circumvent possible incompatibilities when working on ML level.
  2198 
  2199 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2200 
  2201 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2202 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2203 
  2204 * New syntax for Haskell-like list comprehension (input only), eg.
  2205 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2206 
  2207 * The special syntax for function "filter" has changed from [x :
  2208 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2209 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2210 
  2211 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2212 defined on nat only, as an abbreviation for [a..<Suc b]
  2213 INCOMPATIBILITY.
  2214 
  2215 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2216 
  2217 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2218 
  2219 * New lemma collection field_simps (an extension of ring_simps) for
  2220 manipulating (in)equations involving division. Multiplies with all
  2221 denominators that can be proved to be non-zero (in equations) or
  2222 positive/negative (in inequations).
  2223 
  2224 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2225 have been improved and renamed to ring_simps, group_simps and
  2226 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2227 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2228 
  2229 * Theory Library/Commutative_Ring: switched from recdef to function
  2230 package; constants add, mul, pow now curried.  Infix syntax for
  2231 algebraic operations.
  2232 
  2233 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2234 INCOMPATIBILITY.
  2235 
  2236 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2237 INCOMPATIBILITY.
  2238 
  2239 * HOL/records: generalised field-update to take a function on the
  2240 field rather than the new value: r(|A := x|) is translated to A_update
  2241 (K x) r The K-combinator that is internally used is called K_record.
  2242 INCOMPATIBILITY: Usage of the plain update functions has to be
  2243 adapted.
  2244  
  2245 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2246 * x = 0, which are required for a semiring.  Richer structures do not
  2247 inherit from semiring_0 anymore, because this property is a theorem
  2248 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2249 there is more to prove, but this is mostly trivial.
  2250 
  2251 * Class "recpower" is generalized to arbitrary monoids, not just
  2252 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2253 commutativity or semiring properties additionally.
  2254 
  2255 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2256 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2257 better use 'abbreviation'.
  2258 
  2259 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2260 
  2261 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2262 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2263 significant changes for setting up numeral syntax for types:
  2264   - New constants Numeral.pred and Numeral.succ instead
  2265       of former Numeral.bin_pred and Numeral.bin_succ.
  2266   - Use integer operations instead of bin_add, bin_mult and so on.
  2267   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2268   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2269 
  2270 See src/HOL/Integ/IntArith.thy for an example setup.
  2271 
  2272 * Command 'normal_form' computes the normal form of a term that may
  2273 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2274 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2275 heavy-duty computations because the functions are compiled to ML
  2276 first.  Correspondingly, a method "normalization" is provided.  See
  2277 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2278 
  2279 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2280 25 like -->); output depends on the "iff" print_mode, the default is
  2281 "A = B" (with priority 50).
  2282 
  2283 * Relations less (<) and less_eq (<=) are also available on type bool.
  2284 Modified syntax to disallow nesting without explicit parentheses,
  2285 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2286 INCOMPATIBILITY.
  2287 
  2288 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2289 
  2290 * Relation composition operator "op O" now has precedence 75 and binds
  2291 stronger than union and intersection. INCOMPATIBILITY.
  2292 
  2293 * The old set interval syntax "{m..n(}" (and relatives) has been
  2294 removed.  Use "{m..<n}" (and relatives) instead.
  2295 
  2296 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2297 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2298 ``declare [[simproc del: neq]]''.
  2299 
  2300 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2301 True/False.
  2302 
  2303 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2304 
  2305 * Theorem setsum_mult renamed to setsum_right_distrib.
  2306 
  2307 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2308 ``rule'' method.
  2309 
  2310 * Reimplemented methods "sat" and "satx", with several improvements:
  2311 goals no longer need to be stated as "<prems> ==> False", equivalences
  2312 (i.e. "=" on type bool) are handled, variable names of the form
  2313 "lit_<n>" are no longer reserved, significant speedup.
  2314 
  2315 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2316 zChaff is still supported as well.
  2317 
  2318 * 'inductive' and 'datatype': provide projections of mutual rules,
  2319 bundled as foo_bar.inducts;
  2320 
  2321 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2322 Library.
  2323 
  2324 * Library: moved theory Accessible_Part to main HOL.
  2325 
  2326 * Library: added theory Coinductive_List of potentially infinite lists
  2327 as greatest fixed-point.
  2328 
  2329 * Library: added theory AssocList which implements (finite) maps as
  2330 association lists.
  2331 
  2332 * Method "evaluation" solves goals (i.e. a boolean expression)
  2333 efficiently by compiling it to ML.  The goal is "proved" (via an
  2334 oracle) if it evaluates to True.
  2335 
  2336 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2337 also when invoked by the simplifier.  This results in the Simplifier
  2338 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2339 Configuration option fast_arith_split_limit=0 recovers the old
  2340 behavior.
  2341 
  2342 * Support for hex (0x20) and binary (0b1001) numerals.
  2343 
  2344 * New method: reify eqs (t), where eqs are equations for an
  2345 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2346 parameter, computes a term s::'b and a list xs::'a list and proves the
  2347 theorem I xs s = t. This is also known as reification or quoting. The
  2348 resulting theorem is applied to the subgoal to substitute t with I xs
  2349 s.  If t is omitted, the subgoal itself is reified.
  2350 
  2351 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2352 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2353 where f is supposed to be a computable function (in the sense of code
  2354 generattion). The method uses reify to compute s and xs as above then
  2355 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2356 r and finally gets the theorem t = r, which is again applied to the
  2357 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2358 
  2359 * Reflection: Automatic reification now handels binding, an example is
  2360 available in src/HOL/ex/ReflectionEx.thy
  2361 
  2362 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2363 command 'statespace' that is similar to 'record', but introduces an
  2364 abstract specification based on the locale infrastructure instead of
  2365 HOL types.  This leads to extra flexibility in composing state spaces,
  2366 in particular multiple inheritance and renaming of components.
  2367 
  2368 
  2369 *** HOL-Complex ***
  2370 
  2371 * Hyperreal: Functions root and sqrt are now defined on negative real
  2372 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2373 Nonnegativity side conditions have been removed from many lemmas, so
  2374 that more subgoals may now be solved by simplification; potential
  2375 INCOMPATIBILITY.
  2376 
  2377 * Real: new type classes formalize real normed vector spaces and
  2378 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2379 and norm :: 'a => real.
  2380 
  2381 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2382 reals into other types. The overloaded constant Reals :: 'a set is now
  2383 defined as range of_real; potential INCOMPATIBILITY.
  2384 
  2385 * Real: proper support for ML code generation, including 'quickcheck'.
  2386 Reals are implemented as arbitrary precision rationals.
  2387 
  2388 * Hyperreal: Several constants that previously worked only for the
  2389 reals have been generalized, so they now work over arbitrary vector
  2390 spaces. Type annotations may need to be added in some cases; potential
  2391 INCOMPATIBILITY.
  2392 
  2393   Infinitesimal  :: ('a::real_normed_vector) star set
  2394   HFinite        :: ('a::real_normed_vector) star set
  2395   HInfinite      :: ('a::real_normed_vector) star set
  2396   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2397   monad          :: ('a::real_normed_vector) star => 'a star set
  2398   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2399   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2400   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2401   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2402   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2403   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2404   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2405   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2406   sgn            :: 'a::real_normed_vector => 'a
  2407   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2408 
  2409 * Complex: Some complex-specific constants are now abbreviations for
  2410 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2411 hnorm.  Other constants have been entirely removed in favor of the
  2412 polymorphic versions (INCOMPATIBILITY):
  2413 
  2414   approx        <-- capprox
  2415   HFinite       <-- CFinite
  2416   HInfinite     <-- CInfinite
  2417   Infinitesimal <-- CInfinitesimal
  2418   monad         <-- cmonad
  2419   galaxy        <-- cgalaxy
  2420   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2421   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2422   (ns)deriv     <-- (ns)cderiv
  2423 
  2424 
  2425 *** HOL-Algebra ***
  2426 
  2427 * Formalisation of ideals and the quotient construction over rings.
  2428 
  2429 * Order and lattice theory no longer based on records.
  2430 INCOMPATIBILITY.
  2431 
  2432 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2433 greatest_closed.  INCOMPATIBILITY.
  2434 
  2435 * Method algebra is now set up via an attribute.  For examples see
  2436 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2437 of algebraic structures.
  2438 
  2439 * Renamed theory CRing to Ring.
  2440 
  2441 
  2442 *** HOL-Nominal ***
  2443 
  2444 * Substantial, yet incomplete support for nominal datatypes (binding
  2445 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2446 src/HOL/Nominal/Examples.  Prospective users should consult
  2447 http://isabelle.in.tum.de/nominal/
  2448 
  2449 
  2450 *** ML ***
  2451 
  2452 * ML basics: just one true type int, which coincides with IntInf.int
  2453 (even on SML/NJ).
  2454 
  2455 * ML within Isar: antiquotations allow to embed statically-checked
  2456 formal entities in the source, referring to the context available at
  2457 compile-time.  For example:
  2458 
  2459 ML {* @{sort "{zero,one}"} *}
  2460 ML {* @{typ "'a => 'b"} *}
  2461 ML {* @{term "%x. x"} *}
  2462 ML {* @{prop "x == y"} *}
  2463 ML {* @{ctyp "'a => 'b"} *}
  2464 ML {* @{cterm "%x. x"} *}
  2465 ML {* @{cprop "x == y"} *}
  2466 ML {* @{thm asm_rl} *}
  2467 ML {* @{thms asm_rl} *}
  2468 ML {* @{type_name c} *}
  2469 ML {* @{type_syntax c} *}
  2470 ML {* @{const_name c} *}
  2471 ML {* @{const_syntax c} *}
  2472 ML {* @{context} *}
  2473 ML {* @{theory} *}
  2474 ML {* @{theory Pure} *}
  2475 ML {* @{theory_ref} *}
  2476 ML {* @{theory_ref Pure} *}
  2477 ML {* @{simpset} *}
  2478 ML {* @{claset} *}
  2479 ML {* @{clasimpset} *}
  2480 
  2481 The same works for sources being ``used'' within an Isar context.
  2482 
  2483 * ML in Isar: improved error reporting; extra verbosity with
  2484 ML_Context.trace enabled.
  2485 
  2486 * Pure/General/table.ML: the join operations now works via exceptions
  2487 DUP/SAME instead of type option. This is simpler in simple cases, and
  2488 admits slightly more efficient complex applications.
  2489 
  2490 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2491 use Context.generic instead of just theory.
  2492 
  2493 * Pure: datatype Context.generic joins theory/Proof.context and
  2494 provides some facilities for code that works in either kind of
  2495 context, notably GenericDataFun for uniform theory and proof data.
  2496 
  2497 * Pure: simplified internal attribute type, which is now always
  2498 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2499 local (Proof.context) attributes have been discontinued, while
  2500 minimizing code duplication. Thm.rule_attribute and
  2501 Thm.declaration_attribute build canonical attributes; see also structure
  2502 Context for further operations on Context.generic, notably
  2503 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2504 declarations and definitions.
  2505 
  2506 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2507 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2508 init only required for impure data. INCOMPATIBILITY: empty really need
  2509 to be empty (no dependencies on theory content!)
  2510 
  2511 * Pure/kernel: consts certification ignores sort constraints given in
  2512 signature declarations. (This information is not relevant to the
  2513 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2514 potential INCOMPATIBILITY.
  2515 
  2516 * Pure: axiomatic type classes are now purely definitional, with
  2517 explicit proofs of class axioms and super class relations performed
  2518 internally. See Pure/axclass.ML for the main internal interfaces --
  2519 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2520 AxClass.axiomatize_class/classrel/arity supersede
  2521 Sign.add_classes/classrel/arities.
  2522 
  2523 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2524 global/local versions on theory vs. Proof.context have been
  2525 discontinued; Attrib.syntax and Method.syntax have been adapted
  2526 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2527 attributes, methods, etc.
  2528 
  2529 * Pure: several functions of signature "... -> theory -> theory * ..."
  2530 have been reoriented to "... -> theory -> ... * theory" in order to
  2531 allow natural usage in combination with the ||>, ||>>, |-> and
  2532 fold_map combinators.
  2533 
  2534 * Pure: official theorem names (closed derivations) and additional
  2535 comments (tags) are now strictly separate.  Name hints -- which are
  2536 maintained as tags -- may be attached any time without affecting the
  2537 derivation.
  2538 
  2539 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2540 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2541 achieve the old behaviour.
  2542 
  2543 * Pure: the "Goal" constant is now called "prop", supporting a
  2544 slightly more general idea of ``protecting'' meta-level rule
  2545 statements.
  2546 
  2547 * Pure: Logic.(un)varify only works in a global context, which is now
  2548 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2549 Logic.legacy_(un)varify as temporary workaround.
  2550 
  2551 * Pure: structure Name provides scalable operations for generating
  2552 internal variable names, notably Name.variants etc.  This replaces
  2553 some popular functions from term.ML:
  2554 
  2555   Term.variant		->  Name.variant
  2556   Term.variantlist	->  Name.variant_list
  2557   Term.invent_names	->  Name.invent_list
  2558 
  2559 Note that low-level renaming rarely occurs in new code -- operations
  2560 from structure Variable are used instead (see below).
  2561 
  2562 * Pure: structure Variable provides fundamental operations for proper
  2563 treatment of fixed/schematic variables in a context.  For example,
  2564 Variable.import introduces fixes for schematics of given facts and
  2565 Variable.export reverses the effect (up to renaming) -- this replaces
  2566 various freeze_thaw operations.
  2567 
  2568 * Pure: structure Goal provides simple interfaces for
  2569 init/conclude/finish and tactical prove operations (replacing former
  2570 Tactic.prove).  Goal.prove is the canonical way to prove results
  2571 within a given context; Goal.prove_global is a degraded version for
  2572 theory level goals, including a global Drule.standard.  Note that
  2573 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2574 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2575 in a locale context).
  2576 
  2577 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2578 and type checking (Syntax.check_term etc.), with common combinations
  2579 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2580 which are considered legacy and await removal.
  2581 
  2582 * Pure/Syntax: generic interfaces for type unchecking
  2583 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2584 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2585 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2586 available for convenience, but refer to the very same operations using
  2587 a mere theory instead of a full context.
  2588 
  2589 * Isar: simplified treatment of user-level errors, using exception
  2590 ERROR of string uniformly.  Function error now merely raises ERROR,
  2591 without any side effect on output channels.  The Isar toplevel takes
  2592 care of proper display of ERROR exceptions.  ML code may use plain
  2593 handle/can/try; cat_error may be used to concatenate errors like this:
  2594 
  2595   ... handle ERROR msg => cat_error msg "..."
  2596 
  2597 Toplevel ML code (run directly or through the Isar toplevel) may be
  2598 embedded into the Isar toplevel with exception display/debug like
  2599 this:
  2600 
  2601   Isar.toplevel (fn () => ...)
  2602 
  2603 INCOMPATIBILITY, removed special transform_error facilities, removed
  2604 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2605 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2606 -- use plain ERROR instead.
  2607 
  2608 * Isar: theory setup now has type (theory -> theory), instead of a
  2609 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2610 
  2611 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2612 ProofContext.debug/verbose flags.
  2613 
  2614 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2615 theory before entering a proof state.  Transactions now always see a
  2616 quasi-functional intermediate checkpoint, both in interactive and
  2617 batch mode.
  2618 
  2619 * Isar: simplified interfaces for outer syntax.  Renamed
  2620 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2621 OuterSyntax.add_parsers -- this functionality is now included in
  2622 OuterSyntax.command etc.  INCOMPATIBILITY.
  2623 
  2624 * Simplifier: the simpset of a running simplification process now
  2625 contains a proof context (cf. Simplifier.the_context), which is the
  2626 very context that the initial simpset has been retrieved from (by
  2627 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2628 (solver, looper etc.) may depend on arbitrary proof data.
  2629 
  2630 * Simplifier.inherit_context inherits the proof context (plus the
  2631 local bounds) of the current simplification process; any simproc
  2632 etc. that calls the Simplifier recursively should do this!  Removed
  2633 former Simplifier.inherit_bounds, which is already included here --
  2634 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2635 specify an explicit context using Simplifier.context/theory_context.
  2636 
  2637 * Simplifier/Classical Reasoner: more abstract interfaces
  2638 change_simpset/claset for modifying the simpset/claset reference of a
  2639 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2640 INCOMPATIBILITY.
  2641 
  2642 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2643 "Trueprop" etc.
  2644 
  2645 
  2646 *** System ***
  2647 
  2648 * settings: the default heap location within ISABELLE_HOME_USER now
  2649 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2650 Isabelle installations.
  2651 
  2652 * isabelle-process: option -S (secure mode) disables some critical
  2653 operations, notably runtime compilation and evaluation of ML source
  2654 code.
  2655 
  2656 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2657 
  2658 * Support for parallel execution, using native multicore support of
  2659 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2660 independent theories, according to the given theory header
  2661 specifications. The maximum number of worker threads is specified via
  2662 usedir option -M or the "max-threads" setting in Proof General. A
  2663 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2664 to 6 on a 8-core machine.  User-code needs to observe certain
  2665 guidelines for thread-safe programming, see appendix A in the Isar
  2666 Implementation manual.
  2667 
  2668 
  2669 
  2670 New in Isabelle2005 (October 2005)
  2671 ----------------------------------
  2672 
  2673 *** General ***
  2674 
  2675 * Theory headers: the new header syntax for Isar theories is
  2676 
  2677   theory <name>
  2678   imports <theory1> ... <theoryN>
  2679   uses <file1> ... <fileM>
  2680   begin
  2681 
  2682 where the 'uses' part is optional.  The previous syntax
  2683 
  2684   theory <name> = <theory1> + ... + <theoryN>:
  2685 
  2686 will disappear in the next release.  Use isatool fixheaders to convert
  2687 existing theory files.  Note that there is no change in ancient
  2688 non-Isar theories now, but these will disappear soon.
  2689 
  2690 * Theory loader: parent theories can now also be referred to via
  2691 relative and absolute paths.
  2692 
  2693 * Command 'find_theorems' searches for a list of criteria instead of a
  2694 list of constants. Known criteria are: intro, elim, dest, name:string,
  2695 simp:term, and any term. Criteria can be preceded by '-' to select
  2696 theorems that do not match. Intro, elim, dest select theorems that
  2697 match the current goal, name:s selects theorems whose fully qualified
  2698 name contain s, and simp:term selects all simplification rules whose
  2699 lhs match term.  Any other term is interpreted as pattern and selects
  2700 all theorems matching the pattern. Available in ProofGeneral under
  2701 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2702 
  2703   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2704 
  2705 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2706 matching the current goal as introduction rule and not having "HOL."
  2707 in their name (i.e. not being defined in theory HOL).
  2708 
  2709 * Command 'thms_containing' has been discontinued in favour of
  2710 'find_theorems'; INCOMPATIBILITY.
  2711 
  2712 * Communication with Proof General is now 8bit clean, which means that
  2713 Unicode text in UTF-8 encoding may be used within theory texts (both
  2714 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2715 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2716 
  2717   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2718   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2719 
  2720 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2721 Classical Reasoner.  Typical big applications run around 2 times
  2722 faster.
  2723 
  2724 
  2725 *** Document preparation ***
  2726 
  2727 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2728 of raw sources.  Only those symbols that do not require additional
  2729 LaTeX packages (depending on comments in isabellesym.sty) are
  2730 displayed properly, everything else is left verbatim.  isatool display
  2731 and isatool print are used as front ends (these are subject to the
  2732 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2733 
  2734 * Command tags control specific markup of certain regions of text,
  2735 notably folding and hiding.  Predefined tags include "theory" (for
  2736 theory begin and end), "proof" for proof commands, and "ML" for
  2737 commands involving ML code; the additional tags "visible" and
  2738 "invisible" are unused by default.  Users may give explicit tag
  2739 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2740 interpretation of tags is determined by the LaTeX job during document
  2741 preparation: see option -V of isatool usedir, or options -n and -t of
  2742 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2743 \isadroptag.
  2744 
  2745 Several document versions may be produced at the same time via isatool
  2746 usedir (the generated index.html will link all of them).  Typical
  2747 specifications include ''-V document=theory,proof,ML'' to present
  2748 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2749 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2750 these parts without any formal replacement text.  The Isabelle site
  2751 default settings produce ''document'' and ''outline'' versions as
  2752 specified above.
  2753 
  2754 * Several new antiquotations:
  2755 
  2756   @{term_type term} prints a term with its type annotated;
  2757 
  2758   @{typeof term} prints the type of a term;
  2759 
  2760   @{const const} is the same as @{term const}, but checks that the
  2761   argument is a known logical constant;
  2762 
  2763   @{term_style style term} and @{thm_style style thm} print a term or
  2764   theorem applying a "style" to it
  2765 
  2766   @{ML text}
  2767 
  2768 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2769 definitions, equations, inequations etc., 'concl' printing only the
  2770 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2771 to print the specified premise.  TermStyle.add_style provides an ML
  2772 interface for introducing further styles.  See also the "LaTeX Sugar"
  2773 document practical applications.  The ML antiquotation prints
  2774 type-checked ML expressions verbatim.
  2775 
  2776 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2777 and 'text' support optional locale specification '(in loc)', which
  2778 specifies the default context for interpreting antiquotations.  For
  2779 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2780 
  2781 * Option 'locale=NAME' of antiquotations specifies an alternative
  2782 context interpreting the subsequent argument.  For example: @{thm
  2783 [locale=lattice] inf_assoc}.
  2784 
  2785 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2786 a proof context.
  2787 
  2788 * Proper output of antiquotations for theory commands involving a
  2789 proof context (such as 'locale' or 'theorem (in loc) ...').
  2790 
  2791 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2792 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2793 
  2794 * isatool usedir: new option -C (default true) controls whether option
  2795 -D should include a copy of the original document directory; -C false
  2796 prevents unwanted effects such as copying of administrative CVS data.
  2797 
  2798 
  2799 *** Pure ***
  2800 
  2801 * Considerably improved version of 'constdefs' command.  Now performs
  2802 automatic type-inference of declared constants; additional support for
  2803 local structure declarations (cf. locales and HOL records), see also
  2804 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2805 sequential dependencies of definitions within a single 'constdefs'
  2806 section; moreover, the declared name needs to be an identifier.  If
  2807 all fails, consider to fall back on 'consts' and 'defs' separately.
  2808 
  2809 * Improved indexed syntax and implicit structures.  First of all,
  2810 indexed syntax provides a notational device for subscripted
  2811 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2812 expressions.  Secondly, in a local context with structure
  2813 declarations, number indexes \<^sub>n or the empty index (default
  2814 number 1) refer to a certain fixed variable implicitly; option
  2815 show_structs controls printing of implicit structures.  Typical
  2816 applications of these concepts involve record types and locales.
  2817 
  2818 * New command 'no_syntax' removes grammar declarations (and
  2819 translations) resulting from the given syntax specification, which is
  2820 interpreted in the same manner as for the 'syntax' command.
  2821 
  2822 * 'Advanced' translation functions (parse_translation etc.) may depend
  2823 on the signature of the theory context being presently used for
  2824 parsing/printing, see also isar-ref manual.
  2825 
  2826 * Improved 'oracle' command provides a type-safe interface to turn an
  2827 ML expression of type theory -> T -> term into a primitive rule of
  2828 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2829 is already included here); see also FOL/ex/IffExample.thy;
  2830 INCOMPATIBILITY.
  2831 
  2832 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2833 before); "cI" is no longer bound, use "c.intro" instead.
  2834 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2835 axclasses vs. locales.
  2836 
  2837 * Improved internal renaming of symbolic identifiers -- attach primes
  2838 instead of base 26 numbers.
  2839 
  2840 * New flag show_question_marks controls printing of leading question
  2841 marks in schematic variable names.
  2842 
  2843 * In schematic variable names, *any* symbol following \<^isub> or
  2844 \<^isup> is now treated as part of the base name.  For example, the
  2845 following works without printing of awkward ".0" indexes:
  2846 
  2847   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2848     by simp
  2849 
  2850 * Inner syntax includes (*(*nested*) comments*).
  2851 
  2852 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2853 annotations as "(00...)".
  2854 
  2855 * Clear separation of logical types and nonterminals, where the latter
  2856 may only occur in 'syntax' specifications or type abbreviations.
  2857 Before that distinction was only partially implemented via type class
  2858 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2859 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2860 exotic syntax specifications may require further adaption
  2861 (e.g. Cube/Cube.thy).
  2862 
  2863 * Removed obsolete type class "logic", use the top sort {} instead.
  2864 Note that non-logical types should be declared as 'nonterminals'
  2865 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2866 specifications.
  2867 
  2868 * Attributes 'induct' and 'cases': type or set names may now be
  2869 locally fixed variables as well.
  2870 
  2871 * Simplifier: can now control the depth to which conditional rewriting
  2872 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2873 Limit.
  2874 
  2875 * Simplifier: simplification procedures may now take the current
  2876 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2877 interface), which is very useful for calling the Simplifier
  2878 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2879 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2880 low-level mk_simproc no longer applies Logic.varify internally, to
  2881 allow for use in a context of fixed variables.
  2882 
  2883 * thin_tac now works even if the assumption being deleted contains !!
  2884 or ==>.  More generally, erule now works even if the major premise of
  2885 the elimination rule contains !! or ==>.
  2886 
  2887 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2888 
  2889 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2890 from Pure, which contains all common declarations already.  Both
  2891 theories are defined via plain Isabelle/Isar .thy files.
  2892 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2893 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2894 use isatool fixcpure to adapt your theory and ML sources.
  2895 
  2896 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2897 selections of theorems in named facts via index ranges.
  2898 
  2899 * 'print_theorems': in theory mode, really print the difference
  2900 wrt. the last state (works for interactive theory development only),
  2901 in proof mode print all local facts (cf. 'print_facts');
  2902 
  2903 * 'hide': option '(open)' hides only base names.
  2904 
  2905 * More efficient treatment of intermediate checkpoints in interactive
  2906 theory development.
  2907 
  2908 * Code generator is now invoked via code_module (incremental code
  2909 generation) and code_library (modular code generation, ML structures
  2910 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2911 must be quoted when used as identifiers.
  2912 
  2913 * New 'value' command for reading, evaluating and printing terms using
  2914 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2915 quoted when used as identifier.
  2916 
  2917 
  2918 *** Locales ***
  2919 
  2920 * New commands for the interpretation of locale expressions in
  2921 theories (1), locales (2) and proof contexts (3).  These generate
  2922 proof obligations from the expression specification.  After the
  2923 obligations have been discharged, theorems of the expression are added
  2924 to the theory, target locale or proof context.  The synopsis of the
  2925 commands is a follows:
  2926 
  2927   (1) interpretation expr inst
  2928   (2) interpretation target < expr
  2929   (3) interpret expr inst
  2930 
  2931 Interpretation in theories and proof contexts require a parameter
  2932 instantiation of terms from the current context.  This is applied to
  2933 specifications and theorems of the interpreted expression.
  2934 Interpretation in locales only permits parameter renaming through the
  2935 locale expression.  Interpretation is smart in that interpretations
  2936 that are active already do not occur in proof obligations, neither are
  2937 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2938 inspect active interpretations of a particular locale.  For details,
  2939 see the Isar Reference manual.  Examples can be found in
  2940 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2941 
  2942 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2943 'interpret' instead.
  2944 
  2945 * New context element 'constrains' for adding type constraints to
  2946 parameters.
  2947 
  2948 * Context expressions: renaming of parameters with syntax
  2949 redeclaration.
  2950 
  2951 * Locale declaration: 'includes' disallowed.
  2952 
  2953 * Proper static binding of attribute syntax -- i.e. types / terms /
  2954 facts mentioned as arguments are always those of the locale definition
  2955 context, independently of the context of later invocations.  Moreover,
  2956 locale operations (renaming and type / term instantiation) are applied
  2957 to attribute arguments as expected.
  2958 
  2959 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2960 actual attributes; rare situations may require Attrib.attribute to
  2961 embed those attributes into Attrib.src that lack concrete syntax.
  2962 Attribute implementations need to cooperate properly with the static
  2963 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2964 Attrib.XXX_thm etc. already do the right thing without further
  2965 intervention.  Only unusual applications -- such as "where" or "of"
  2966 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2967 on the context and the facts involved -- may have to assign parsed
  2968 values to argument tokens explicitly.
  2969 
  2970 * Changed parameter management in theorem generation for long goal
  2971 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2972 theorem statement in rare situations.
  2973 
  2974 * Locale inspection command 'print_locale' omits notes elements.  Use
  2975 'print_locale!' to have them included in the output.
  2976 
  2977 
  2978 *** Provers ***
  2979 
  2980 * Provers/hypsubst.ML: improved version of the subst method, for
  2981 single-step rewriting: it now works in bound variable contexts. New is
  2982 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2983 rewrite a different subterm than the original subst method, which is
  2984 still available as 'simplesubst'.
  2985 
  2986 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2987 and quasi orders.
  2988 
  2989 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2990 reflexive-transitive closure of relations.
  2991 
  2992 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2993 limit (previously hard-coded with a value of 20) user-definable.
  2994 
  2995 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2996 is peformed already.  Object-logics merely need to finish their
  2997 initial simpset configuration as before.  INCOMPATIBILITY.
  2998 
  2999 
  3000 *** HOL ***
  3001 
  3002 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3003 
  3004   syntax (epsilon)
  3005     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3006 
  3007 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3008 and x-symbol; use option '-m epsilon' to get it actually printed.
  3009 Moreover, the mathematically important symbolic identifier \<epsilon>
  3010 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3011 
  3012 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3013 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3014 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3015 support corresponding Isar calculations.
  3016 
  3017 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3018 instead of ":".
  3019 
  3020 * theory SetInterval: changed the syntax for open intervals:
  3021 
  3022   Old       New
  3023   {..n(}    {..<n}
  3024   {)n..}    {n<..}
  3025   {m..n(}   {m..<n}
  3026   {)m..n}   {m<..n}
  3027   {)m..n(}  {m<..<n}
  3028 
  3029 The old syntax is still supported but will disappear in the next
  3030 release.  For conversion use the following Emacs search and replace
  3031 patterns (these are not perfect but work quite well):
  3032 
  3033   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3034   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3035 
  3036 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3037 equalities in commutative rings; method 'algebra' provides a generic
  3038 interface.
  3039 
  3040 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3041 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3042 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3043 be a tuple pattern.
  3044 
  3045 Some new syntax forms are available:
  3046 
  3047   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3048   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3049   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3050   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3051 
  3052 The latter form "\<Sum>x < k. e" used to be based on a separate
  3053 function "Summation", which has been discontinued.
  3054 
  3055 * theory Finite_Set: in structured induction proofs, the insert case
  3056 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3057 (insert F x)'.
  3058 
  3059 * The 'refute' command has been extended to support a much larger
  3060 fragment of HOL, including axiomatic type classes, constdefs and
  3061 typedefs, inductive datatypes and recursion.
  3062 
  3063 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3064 Requires zChaff with proof generation to be installed.  See
  3065 HOL/ex/SAT_Examples.thy for examples.
  3066 
  3067 * Datatype induction via method 'induct' now preserves the name of the
  3068 induction variable. For example, when proving P(xs::'a list) by
  3069 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3070 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3071 in unstructured proof scripts.
  3072 
  3073 * Reworked implementation of records.  Improved scalability for
  3074 records with many fields, avoiding performance problems for type
  3075 inference. Records are no longer composed of nested field types, but
  3076 of nested extension types. Therefore the record type only grows linear
  3077 in the number of extensions and not in the number of fields.  The
  3078 top-level (users) view on records is preserved.  Potential
  3079 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3080 old record representation. The type generated for a record is called
  3081 <record_name>_ext_type.
  3082 
  3083 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3084 proofs triggered by a record definition or a simproc (if
  3085 quick_and_dirty is enabled).  Definitions of large records can take
  3086 quite long.
  3087 
  3088 New simproc record_upd_simproc for simplification of multiple record
  3089 updates enabled by default.  Moreover, trivial updates are also
  3090 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3091 occasionally, since simplification is more powerful by default.
  3092 
  3093 * typedef: proper support for polymorphic sets, which contain extra
  3094 type-variables in the term.
  3095 
  3096 * Simplifier: automatically reasons about transitivity chains
  3097 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3098 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3099 old proofs break occasionally as simplification may now solve more
  3100 goals than previously.
  3101 
  3102 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3103 present.  Works for all partial orders (class "order"), in particular
  3104 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3105 just like y <= x.
  3106 
  3107 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3108 bound variable or a constant then the let is unfolded.  Otherwise
  3109 first a is simplified to b, and then f b is simplified to g. If
  3110 possible we abstract b from g arriving at "let x = b in h x",
  3111 otherwise we unfold the let and arrive at g.  The simproc can be
  3112 enabled/disabled by the reference use_let_simproc.  Potential
  3113 INCOMPATIBILITY since simplification is more powerful by default.
  3114 
  3115 * Classical reasoning: the meson method now accepts theorems as arguments.
  3116 
  3117 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3118 jobs to provide advice on the provability of subgoals.
  3119 
  3120 * Theory OrderedGroup and Ring_and_Field: various additions and
  3121 improvements to faciliate calculations involving equalities and
  3122 inequalities.
  3123 
  3124 The following theorems have been eliminated or modified
  3125 (INCOMPATIBILITY):
  3126 
  3127   abs_eq             now named abs_of_nonneg
  3128   abs_of_ge_0        now named abs_of_nonneg
  3129   abs_minus_eq       now named abs_of_nonpos
  3130   imp_abs_id         now named abs_of_nonneg
  3131   imp_abs_neg_id     now named abs_of_nonpos
  3132   mult_pos           now named mult_pos_pos
  3133   mult_pos_le        now named mult_nonneg_nonneg
  3134   mult_pos_neg_le    now named mult_nonneg_nonpos
  3135   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3136   mult_neg           now named mult_neg_neg
  3137   mult_neg_le        now named mult_nonpos_nonpos
  3138 
  3139 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3140      
  3141      zero_le_square
  3142      not_square_less_zero 
  3143 
  3144   The following lemmas have been deleted from Real/RealPow:
  3145   
  3146      realpow_zero_zero
  3147      realpow_two
  3148      realpow_less
  3149      zero_le_power
  3150      realpow_two_le
  3151      abs_realpow_two
  3152      realpow_two_abs     
  3153 
  3154 * Theory Parity: added rules for simplifying exponents.
  3155 
  3156 * Theory List:
  3157 
  3158 The following theorems have been eliminated or modified
  3159 (INCOMPATIBILITY):
  3160 
  3161   list_all_Nil       now named list_all.simps(1)
  3162   list_all_Cons      now named list_all.simps(2)
  3163   list_all_conv      now named list_all_iff
  3164   set_mem_eq         now named mem_iff
  3165 
  3166 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3167 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3168 
  3169 
  3170 *** HOL-Complex ***
  3171 
  3172 * Theory RealDef: better support for embedding natural numbers and
  3173 integers in the reals.
  3174 
  3175 The following theorems have been eliminated or modified
  3176 (INCOMPATIBILITY):
  3177 
  3178   exp_ge_add_one_self  now requires no hypotheses
  3179   real_of_int_add      reversed direction of equality (use [symmetric])
  3180   real_of_int_minus    reversed direction of equality (use [symmetric])
  3181   real_of_int_diff     reversed direction of equality (use [symmetric])
  3182   real_of_int_mult     reversed direction of equality (use [symmetric])
  3183 
  3184 * Theory RComplete: expanded support for floor and ceiling functions.
  3185 
  3186 * Theory Ln is new, with properties of the natural logarithm
  3187 
  3188 * Hyperreal: There is a new type constructor "star" for making
  3189 nonstandard types.  The old type names are now type synonyms:
  3190 
  3191   hypreal = real star
  3192   hypnat = nat star
  3193   hcomplex = complex star
  3194 
  3195 * Hyperreal: Many groups of similarly-defined constants have been
  3196 replaced by polymorphic versions (INCOMPATIBILITY):
  3197 
  3198   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3199 
  3200   starset      <-- starsetNat, starsetC
  3201   *s*          <-- *sNat*, *sc*
  3202   starset_n    <-- starsetNat_n, starsetC_n
  3203   *sn*         <-- *sNatn*, *scn*
  3204   InternalSets <-- InternalNatSets, InternalCSets
  3205 
  3206   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3207   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3208   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3209   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3210   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3211 
  3212 * Hyperreal: Many type-specific theorems have been removed in favor of
  3213 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3214 
  3215   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3216   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3217   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3218   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3219   right_minus <-- hypreal_add_minus
  3220   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3221   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3222   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3223   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3224   mult_1_right <-- hcomplex_mult_one_right
  3225   mult_zero_left <-- hcomplex_mult_zero_left
  3226   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3227   right_distrib <-- hypnat_add_mult_distrib2
  3228   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3229   right_inverse <-- hypreal_mult_inverse
  3230   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3231   order_refl <-- {hypreal,hypnat}_le_refl
  3232   order_trans <-- {hypreal,hypnat}_le_trans
  3233   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3234   order_less_le <-- {hypreal,hypnat}_less_le
  3235   linorder_linear <-- {hypreal,hypnat}_le_linear
  3236   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3237   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3238   add_nonneg_nonneg <-- hypreal_le_add_order
  3239 
  3240 * Hyperreal: Separate theorems having to do with type-specific
  3241 versions of constants have been merged into theorems that apply to the
  3242 new polymorphic constants (INCOMPATIBILITY):
  3243 
  3244   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3245   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3246   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3247   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3248   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3249   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3250   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3251   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3252   STAR_diff <-- {STAR,STARC}_diff
  3253   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3254     STARC_hcomplex_of_complex}_image_subset
  3255   starset_n_Un <-- starset{Nat,C}_n_Un
  3256   starset_n_Int <-- starset{Nat,C}_n_Int
  3257   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3258   starset_n_diff <-- starset{Nat,C}_n_diff
  3259   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3260   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3261   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3262   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3263   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3264   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3265   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3266   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3267   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3268   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3269   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3270   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3271   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3272   starfun_diff <-- starfun{C,RC,CR}_diff
  3273   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3274   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3275   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3276   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3277   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3278   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3279   starfun_Id <-- starfunC_Id
  3280   starfun_approx <-- starfun{Nat,CR}_approx
  3281   starfun_capprox <-- starfun{C,RC}_capprox
  3282   starfun_abs <-- starfunNat_rabs
  3283   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3284   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3285   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3286   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3287   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3288   starfun_add_approx <-- starfunCR_add_approx
  3289   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3290   starfun_divide <-- starfun{C,CR,RC}_divide
  3291   starfun_n <-- starfun{Nat,C}_n
  3292   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3293   starfun_n_add <-- starfun{Nat,C}_n_add
  3294   starfun_n_add_minus <-- starfunNat_n_add_minus
  3295   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3296   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3297   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3298 
  3299   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3300   star_n_minus <-- {hypreal,hcomplex}_minus
  3301   star_n_diff <-- {hypreal,hcomplex}_diff
  3302   star_n_mult <-- {hypreal,hcomplex}_mult
  3303   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3304   star_n_le <-- {hypreal,hypnat}_le
  3305   star_n_less <-- {hypreal,hypnat}_less
  3306   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3307   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3308   star_n_abs <-- hypreal_hrabs
  3309   star_n_divide <-- hcomplex_divide
  3310 
  3311   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3312   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3313   star_of_diff <-- hypreal_of_real_diff
  3314   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3315   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3316   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3317   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3318   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3319   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3320   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3321   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3322   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3323   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3324   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3325   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3326   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3327   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3328   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3329   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3330   star_of_power <-- hypreal_of_real_power
  3331   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3332 
  3333 * Hyperreal: new method "transfer" that implements the transfer
  3334 principle of nonstandard analysis. With a subgoal that mentions
  3335 nonstandard types like "'a star", the command "apply transfer"
  3336 replaces it with an equivalent one that mentions only standard types.
  3337 To be successful, all free variables must have standard types; non-
  3338 standard variables must have explicit universal quantifiers.
  3339 
  3340 * Hyperreal: A theory of Taylor series.
  3341 
  3342 
  3343 *** HOLCF ***
  3344 
  3345 * Discontinued special version of 'constdefs' (which used to support
  3346 continuous functions) in favor of the general Pure one with full
  3347 type-inference.
  3348 
  3349 * New simplification procedure for solving continuity conditions; it
  3350 is much faster on terms with many nested lambda abstractions (cubic
  3351 instead of exponential time).
  3352 
  3353 * New syntax for domain package: selector names are now optional.
  3354 Parentheses should be omitted unless argument is lazy, for example:
  3355 
  3356   domain 'a stream = cons "'a" (lazy "'a stream")
  3357 
  3358 * New command 'fixrec' for defining recursive functions with pattern
  3359 matching; defining multiple functions with mutual recursion is also
  3360 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3361 sinr, or any data constructor defined by the domain package. The given
  3362 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3363 syntax and examples.
  3364 
  3365 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3366 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3367 but the proof obligation additionally includes an admissibility
  3368 requirement. The packages generate instances of class cpo or pcpo,
  3369 with continuity and strictness theorems for Rep and Abs.
  3370 
  3371 * HOLCF: Many theorems have been renamed according to a more standard naming
  3372 scheme (INCOMPATIBILITY):
  3373 
  3374   foo_inject:  "foo$x = foo$y ==> x = y"
  3375   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3376   foo_less:    "(foo$x << foo$y) = (x << y)"
  3377   foo_strict:  "foo$UU = UU"
  3378   foo_defined: "... ==> foo$x ~= UU"
  3379   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3380 
  3381 
  3382 *** ZF ***
  3383 
  3384 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3385 including the First Isomorphism Theorem (on quotienting by the kernel
  3386 of a homomorphism).
  3387 
  3388 * ZF/Simplifier: install second copy of type solver that actually
  3389 makes use of TC rules declared to Isar proof contexts (or locales);
  3390 the old version is still required for ML proof scripts.
  3391 
  3392 
  3393 *** Cube ***
  3394 
  3395 * Converted to Isar theory format; use locales instead of axiomatic
  3396 theories.
  3397 
  3398 
  3399 *** ML ***
  3400 
  3401 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3402 for ||>, ||>>, |>>,
  3403 
  3404 * Pure/library.ML no longer defines its own option datatype, but uses
  3405 that of the SML basis, which has constructors NONE and SOME instead of
  3406 None and Some, as well as exception Option.Option instead of OPTION.
  3407 The functions the, if_none, is_some, is_none have been adapted
  3408 accordingly, while Option.map replaces apsome.
  3409 
  3410 * Pure/library.ML: the exception LIST has been given up in favour of
  3411 the standard exceptions Empty and Subscript, as well as
  3412 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3413 superceded by the standard hd and tl functions etc.
  3414 
  3415 A number of basic list functions are no longer exported to the ML
  3416 toplevel, as they are variants of predefined functions.  The following
  3417 suggests how one can translate existing code:
  3418 
  3419     rev_append xs ys = List.revAppend (xs, ys)
  3420     nth_elem (i, xs) = List.nth (xs, i)
  3421     last_elem xs = List.last xs
  3422     flat xss = List.concat xss
  3423     seq fs = List.app fs
  3424     partition P xs = List.partition P xs
  3425     mapfilter f xs = List.mapPartial f xs
  3426 
  3427 * Pure/library.ML: several combinators for linear functional
  3428 transformations, notably reverse application and composition:
  3429 
  3430   x |> f                f #> g
  3431   (x, y) |-> f          f #-> g
  3432 
  3433 * Pure/library.ML: introduced/changed precedence of infix operators:
  3434 
  3435   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3436   infix 2 ?;
  3437   infix 3 o oo ooo oooo;
  3438   infix 4 ~~ upto downto;
  3439 
  3440 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3441 infix operators.
  3442 
  3443 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3444 fold_map support linear functional transformations and nesting.  For
  3445 example:
  3446 
  3447   fold f [x1, ..., xN] y =
  3448     y |> f x1 |> ... |> f xN
  3449 
  3450   (fold o fold) f [xs1, ..., xsN] y =
  3451     y |> fold f xs1 |> ... |> fold f xsN
  3452 
  3453   fold f [x1, ..., xN] =
  3454     f x1 #> ... #> f xN
  3455 
  3456   (fold o fold) f [xs1, ..., xsN] =
  3457     fold f xs1 #> ... #> fold f xsN
  3458 
  3459 * Pure/library.ML: the following selectors on type 'a option are
  3460 available:
  3461 
  3462   the:               'a option -> 'a  (*partial*)
  3463   these:             'a option -> 'a  where 'a = 'b list
  3464   the_default: 'a -> 'a option -> 'a
  3465   the_list:          'a option -> 'a list
  3466 
  3467 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3468 basic operations for association lists, following natural argument
  3469 order; moreover the explicit equality predicate passed here avoids
  3470 potentially expensive polymorphic runtime equality checks.
  3471 The old functions may be expressed as follows:
  3472 
  3473   assoc = uncurry (AList.lookup (op =))
  3474   assocs = these oo AList.lookup (op =)
  3475   overwrite = uncurry (AList.update (op =)) o swap
  3476 
  3477 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3478 
  3479   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3480   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3481 
  3482 replacing make_keylist and keyfilter (occassionally used)
  3483 Naive rewrites:
  3484 
  3485   make_keylist = AList.make
  3486   keyfilter = AList.find (op =)
  3487 
  3488 * eq_fst and eq_snd now take explicit equality parameter, thus
  3489   avoiding eqtypes. Naive rewrites:
  3490 
  3491     eq_fst = eq_fst (op =)
  3492     eq_snd = eq_snd (op =)
  3493 
  3494 * Removed deprecated apl and apr (rarely used).
  3495   Naive rewrites:
  3496 
  3497     apl (n, op) =>>= curry op n
  3498     apr (op, m) =>>= fn n => op (n, m)
  3499 
  3500 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3501 provides a reasonably efficient light-weight implementation of sets as
  3502 lists.
  3503 
  3504 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3505 few new operations; existing lookup and update are now curried to
  3506 follow natural argument order (for use with fold etc.);
  3507 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3508 
  3509 * Pure/General: output via the Isabelle channels of
  3510 writeln/warning/error etc. is now passed through Output.output, with a
  3511 hook for arbitrary transformations depending on the print_mode
  3512 (cf. Output.add_mode -- the first active mode that provides a output
  3513 function wins).  Already formatted output may be embedded into further
  3514 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3515 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3516 accommodate easy composition of diagnostic messages etc.  Programmers
  3517 rarely need to care about Output.output or Output.raw at all, with
  3518 some notable exceptions: Output.output is required when bypassing the
  3519 standard channels (writeln etc.), or in token translations to produce
  3520 properly formatted results; Output.raw is required when capturing
  3521 already output material that will eventually be presented to the user
  3522 a second time.  For the default print mode, both Output.output and
  3523 Output.raw have no effect.
  3524 
  3525 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3526 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3527 cumulative results are displayed at the end of a batch session.
  3528 
  3529 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3530 replaced by File.platform_path and File.shell_path (with appropriate
  3531 hooks).  This provides a clean interface for unusual systems where the
  3532 internal and external process view of file names are different.
  3533 
  3534 * Pure: more efficient orders for basic syntactic entities: added
  3535 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3536 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3537 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3538 orders now -- potential INCOMPATIBILITY for code that depends on a
  3539 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3540 Library.sort_strings on result).
  3541 
  3542 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3543 fold_types traverse types/terms from left to right, observing natural
  3544 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3545 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3546 
  3547 * Pure: name spaces have been refined, with significant changes of the
  3548 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3549 to extern(_table).  The plain name entry path is superceded by a
  3550 general 'naming' context, which also includes the 'policy' to produce
  3551 a fully qualified name and external accesses of a fully qualified
  3552 name; NameSpace.extend is superceded by context dependent
  3553 Sign.declare_name.  Several theory and proof context operations modify
  3554 the naming context.  Especially note Theory.restore_naming and
  3555 ProofContext.restore_naming to get back to a sane state; note that
  3556 Theory.add_path is no longer sufficient to recover from
  3557 Theory.absolute_path in particular.
  3558 
  3559 * Pure: new flags short_names (default false) and unique_names
  3560 (default true) for controlling output of qualified names.  If
  3561 short_names is set, names are printed unqualified.  If unique_names is
  3562 reset, the name prefix is reduced to the minimum required to achieve
  3563 the original result when interning again, even if there is an overlap
  3564 with earlier declarations.
  3565 
  3566 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3567 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3568 (useful for printing error messages).  INCOMPATIBILITY.
  3569 
  3570 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3571 Theory.theory are now identified, referring to the universal
  3572 Context.theory (see Pure/context.ML).  Actual signature and theory
  3573 content is managed as theory data.  The old code and interfaces were
  3574 spread over many files and structures; the new arrangement introduces
  3575 considerable INCOMPATIBILITY to gain more clarity:
  3576 
  3577   Context -- theory management operations (name, identity, inclusion,
  3578     parents, ancestors, merge, etc.), plus generic theory data;
  3579 
  3580   Sign -- logical signature and syntax operations (declaring consts,
  3581     types, etc.), plus certify/read for common entities;
  3582 
  3583   Theory -- logical theory operations (stating axioms, definitions,
  3584     oracles), plus a copy of logical signature operations (consts,
  3585     types, etc.); also a few basic management operations (Theory.copy,
  3586     Theory.merge, etc.)
  3587 
  3588 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3589 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3590 for convenience -- they merely return the theory.
  3591 
  3592 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3593 
  3594 * Pure: the Isar proof context type is already defined early in Pure
  3595 as Context.proof (note that ProofContext.context and Proof.context are
  3596 aliases, where the latter is the preferred name).  This enables other
  3597 Isabelle components to refer to that type even before Isar is present.
  3598 
  3599 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3600 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3601 any of these kinds.  For example, Sign.intern typeK is now
  3602 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3603 Theory.hide_types.  Also note that former
  3604 Theory.hide_classes/types/consts are now
  3605 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3606 internalize their arguments!  INCOMPATIBILITY.
  3607 
  3608 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3609 datatype thmref (with constructors Name and NameSelection) instead of
  3610 plain string -- INCOMPATIBILITY;
  3611 
  3612 * Pure: cases produced by proof methods specify options, where NONE
  3613 means to remove case bindings -- INCOMPATIBILITY in
  3614 (RAW_)METHOD_CASES.
  3615 
  3616 * Pure: the following operations retrieve axioms or theorems from a
  3617 theory node or theory hierarchy, respectively:
  3618 
  3619   Theory.axioms_of: theory -> (string * term) list
  3620   Theory.all_axioms_of: theory -> (string * term) list
  3621   PureThy.thms_of: theory -> (string * thm) list
  3622   PureThy.all_thms_of: theory -> (string * thm) list
  3623 
  3624 * Pure: print_tac now outputs the goal through the trace channel.
  3625 
  3626 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3627 Reference Toplevel.debug (default false) controls detailed printing
  3628 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3629 controls execution profiling -- set to 1 for time and 2 for space
  3630 (both increase the runtime).
  3631 
  3632 * Isar session: The initial use of ROOT.ML is now always timed,
  3633 i.e. the log will show the actual process times, in contrast to the
  3634 elapsed wall-clock time that the outer shell wrapper produces.
  3635 
  3636 * Simplifier: improved handling of bound variables (nameless
  3637 representation, avoid allocating new strings).  Simprocs that invoke
  3638 the Simplifier recursively should use Simplifier.inherit_bounds to
  3639 avoid local name clashes.  Failure to do so produces warnings
  3640 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3641 for further details.
  3642 
  3643 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3644 bindings for all theorems stored within a given theory; this may help
  3645 in porting non-Isar theories to Isar ones, while keeping ML proof
  3646 scripts for the time being.
  3647 
  3648 * ML operator HTML.with_charset specifies the charset begin used for
  3649 generated HTML files.  For example:
  3650 
  3651   HTML.with_charset "utf-8" use_thy "Hebrew";
  3652   HTML.with_charset "utf-8" use_thy "Chinese";
  3653 
  3654 
  3655 *** System ***
  3656 
  3657 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3658 isabelle, isatool etc.).
  3659 
  3660 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3661 isatool doc, isatool mkdir, display_drafts etc.).
  3662 
  3663 * isatool usedir: option -f allows specification of the ML file to be
  3664 used by Isabelle; default is ROOT.ML.
  3665 
  3666 * New isatool version outputs the version identifier of the Isabelle
  3667 distribution being used.
  3668 
  3669 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3670 (containing Boolean satisfiability problems) into Isabelle/HOL
  3671 theories.
  3672 
  3673 
  3674 
  3675 New in Isabelle2004 (April 2004)
  3676 --------------------------------
  3677 
  3678 *** General ***
  3679 
  3680 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3681   Replaces linorder.ML.
  3682 
  3683 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3684   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3685   (\<a>...\<z>), are now considered normal letters, and can therefore
  3686   be used anywhere where an ASCII letter (a...zA...Z) has until
  3687   now. COMPATIBILITY: This obviously changes the parsing of some
  3688   terms, especially where a symbol has been used as a binder, say
  3689   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3690   as an identifier.  Fix it by inserting a space around former
  3691   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3692   existing theory and ML files.
  3693 
  3694 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3695 
  3696 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3697   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3698   a normal (but invisible) letter. For multiple letter subscripts repeat
  3699   \<^isub> like this: x\<^isub>1\<^isub>2.
  3700 
  3701 * Pure: There are now sub-/superscripts that can span more than one
  3702   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3703   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3704   superscript. The new control characters are not identifier parts.
  3705 
  3706 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3707   content of "..." to the latex file instead of \isacntrl... . The "..."
  3708   may consist of any printable characters excluding the end bracket >.
  3709 
  3710 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3711   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3712   declare constants "final", which prevents their being given a definition
  3713   later.  It is useful for constants whose behaviour is fixed axiomatically
  3714   rather than definitionally, such as the meta-logic connectives.
  3715 
  3716 * Pure: 'instance' now handles general arities with general sorts
  3717   (i.e. intersections of classes),
  3718 
  3719 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3720   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3721   It can be changed to alter the colors/layout of generated pages.
  3722 
  3723 
  3724 *** Isar ***
  3725 
  3726 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3727   cut_tac, subgoal_tac and thin_tac:
  3728   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3729     locales are no longer forced to write Isar proof scripts.
  3730     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3731     emulations.
  3732   - INCOMPATIBILITY: names of variables to be instantiated may no
  3733     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3734     This is consistent with the instantiation attribute "where".
  3735 
  3736 * Attributes "where" and "of":
  3737   - Now take type variables of instantiated theorem into account when reading
  3738     the instantiation string.  This fixes a bug that caused instantiated
  3739     theorems to have too special types in some circumstances.
  3740   - "where" permits explicit instantiations of type variables.
  3741 
  3742 * Calculation commands "moreover" and "also" no longer interfere with
  3743   current facts ("this"), admitting arbitrary combinations with "then"
  3744   and derived forms.
  3745 
  3746 * Locales:
  3747   - Goal statements involving the context element "includes" no longer
  3748     generate theorems with internal delta predicates (those ending on
  3749     "_axioms") in the premise.
  3750     Resolve particular premise with <locale>.intro to obtain old form.
  3751   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3752     specification and "includes" elements in goal statement.
  3753   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3754     [intro?] and [elim?] (respectively) by default.
  3755   - Experimental command for instantiation of locales in proof contexts:
  3756         instantiate <label>[<attrs>]: <loc>
  3757     Instantiates locale <loc> and adds all its theorems to the current context
  3758     taking into account their attributes.  Label and attrs are optional
  3759     modifiers, like in theorem declarations.  If present, names of
  3760     instantiated theorems are qualified with <label>, and the attributes
  3761     <attrs> are applied after any attributes these theorems might have already.
  3762       If the locale has assumptions, a chained fact of the form
  3763     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3764     are derived.  The command does not support old-style locales declared
  3765     with "locale (open)".
  3766       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3767 
  3768 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3769   (Isar) contexts.
  3770 
  3771 
  3772 *** HOL ***
  3773 
  3774 * Proof import: new image HOL4 contains the imported library from
  3775   the HOL4 system with about 2500 theorems. It is imported by
  3776   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3777   can be used like any other Isabelle image.  See
  3778   HOL/Import/HOL/README for more information.
  3779 
  3780 * Simplifier:
  3781   - Much improved handling of linear and partial orders.
  3782     Reasoners for linear and partial orders are set up for type classes
  3783     "linorder" and "order" respectively, and are added to the default simpset
  3784     as solvers.  This means that the simplifier can build transitivity chains
  3785     to solve goals from the assumptions.
  3786   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3787     of blast or auto after simplification become unnecessary because the goal
  3788     is solved by simplification already.
  3789 
  3790 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3791     all proved in axiomatic type classes for semirings, rings and fields.
  3792 
  3793 * Numerics:
  3794   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3795     now formalized using the Ring_and_Field theory mentioned above.
  3796   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3797     than before, because now they are set up once in a generic manner.
  3798   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3799     Look for the general versions in Ring_and_Field (and Power if they concern
  3800     exponentiation).
  3801 
  3802 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3803 
  3804 * Records:
  3805   - Record types are now by default printed with their type abbreviation
  3806     instead of the list of all field types. This can be configured via
  3807     the reference "print_record_type_abbr".
  3808   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3809     (not enabled by default).
  3810   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3811     EX x. x = sel r to True (not enabled by default).
  3812   - Tactic "record_split_simp_tac" to split and simplify records added.
  3813 
  3814 * 'specification' command added, allowing for definition by
  3815   specification.  There is also an 'ax_specification' command that
  3816   introduces the new constants axiomatically.
  3817 
  3818 * arith(_tac) is now able to generate counterexamples for reals as well.
  3819 
  3820 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3821 
  3822 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3823   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3824 
  3825 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3826   matrix theory to linear programming.
  3827 
  3828 * Unions and Intersections:
  3829   The latex output syntax of UN and INT has been changed
  3830   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3831   i.e. the index formulae has become a subscript.
  3832   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3833 
  3834 * Unions and Intersections over Intervals:
  3835   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3836   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3837   like in normal math, and corresponding versions for < and for intersection.
  3838 
  3839 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3840   lexicographic dictonary ordering has been added as "lexord".
  3841 
  3842 * ML: the legacy theory structures Int and List have been removed. They had
  3843   conflicted with ML Basis Library structures having the same names.
  3844 
  3845 * 'refute' command added to search for (finite) countermodels.  Only works
  3846   for a fragment of HOL.  The installation of an external SAT solver is
  3847   highly recommended.  See "HOL/Refute.thy" for details.
  3848 
  3849 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3850   formulae under an assignment of free variables to random values.
  3851   In contrast to 'refute', it can deal with inductive datatypes,
  3852   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3853   for examples.
  3854 
  3855 
  3856 *** HOLCF ***
  3857 
  3858 * Streams now come with concatenation and are part of the HOLCF image
  3859 
  3860 
  3861 
  3862 New in Isabelle2003 (May 2003)
  3863 ------------------------------
  3864 
  3865 *** General ***
  3866 
  3867 * Provers/simplifier:
  3868 
  3869   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3870     Assumptions are now subject to complete mutual simplification,
  3871     not just from left to right. The simplifier now preserves
  3872     the order of assumptions.
  3873 
  3874     Potential INCOMPATIBILITY:
  3875 
  3876     -- simp sometimes diverges where the old version did
  3877        not, e.g. invoking simp on the goal
  3878 
  3879         [| P (f x); y = x; f x = f y |] ==> Q
  3880 
  3881        now gives rise to the infinite reduction sequence
  3882 
  3883         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3884 
  3885        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3886        kind of problem.
  3887 
  3888     -- Tactics combining classical reasoner and simplification (such as auto)
  3889        are also affected by this change, because many of them rely on
  3890        simp. They may sometimes diverge as well or yield a different numbers
  3891        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3892        in case of problems. Sometimes subsequent calls to the classical
  3893        reasoner will fail because a preceeding call to the simplifier too
  3894        eagerly simplified the goal, e.g. deleted redundant premises.
  3895 
  3896   - The simplifier trace now shows the names of the applied rewrite rules
  3897 
  3898   - You can limit the number of recursive invocations of the simplifier
  3899     during conditional rewriting (where the simplifie tries to solve the
  3900     conditions before applying the rewrite rule):
  3901     ML "simp_depth_limit := n"
  3902     where n is an integer. Thus you can force termination where previously
  3903     the simplifier would diverge.
  3904 
  3905   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3906 
  3907   - No longer aborts on failed congruence proof.  Instead, the
  3908     congruence is ignored.
  3909 
  3910 * Pure: New generic framework for extracting programs from constructive
  3911   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3912   as HOL/Extraction for some case studies.
  3913 
  3914 * Pure: The main goal of the proof state is no longer shown by default, only
  3915 the subgoals. This behaviour is controlled by a new flag.
  3916    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3917 (ML: Proof.show_main_goal).
  3918 
  3919 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3920 rules whose conclusion matches subgoal 1:
  3921       PG menu: Isabelle/Isar -> Show me -> matching rules
  3922 The rules are ordered by how closely they match the subgoal.
  3923 In particular, rules that solve a subgoal outright are displayed first
  3924 (or rather last, the way they are printed).
  3925 (ML: ProofGeneral.print_intros())
  3926 
  3927 * Pure: New flag trace_unify_fail causes unification to print
  3928 diagnostic information (PG: in trace buffer) when it fails. This is
  3929 useful for figuring out why single step proofs like rule, erule or
  3930 assumption failed.
  3931 
  3932 * Pure: Locale specifications now produce predicate definitions
  3933 according to the body of text (covering assumptions modulo local
  3934 definitions); predicate "loc_axioms" covers newly introduced text,
  3935 while "loc" is cumulative wrt. all included locale expressions; the
  3936 latter view is presented only on export into the global theory
  3937 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3938 on the old view without predicates;
  3939 
  3940 * Pure: predefined locales "var" and "struct" are useful for sharing
  3941 parameters (as in CASL, for example); just specify something like
  3942 ``var x + var y + struct M'' as import;
  3943 
  3944 * Pure: improved thms_containing: proper indexing of facts instead of
  3945 raw theorems; check validity of results wrt. current name space;
  3946 include local facts of proof configuration (also covers active
  3947 locales), cover fixed variables in index; may use "_" in term
  3948 specification; an optional limit for the number of printed facts may
  3949 be given (the default is 40);
  3950 
  3951 * Pure: disallow duplicate fact bindings within new-style theory files
  3952 (batch-mode only);
  3953 
  3954 * Provers: improved induct method: assumptions introduced by case
  3955 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3956 the goal statement); "foo" still refers to all facts collectively;
  3957 
  3958 * Provers: the function blast.overloaded has been removed: all constants
  3959 are regarded as potentially overloaded, which improves robustness in exchange
  3960 for slight decrease in efficiency;
  3961 
  3962 * Provers/linorder: New generic prover for transitivity reasoning over
  3963 linear orders.  Note: this prover is not efficient!
  3964 
  3965 * Isar: preview of problems to finish 'show' now produce an error
  3966 rather than just a warning (in interactive mode);
  3967 
  3968 
  3969 *** HOL ***
  3970 
  3971 * arith(_tac)
  3972 
  3973  - Produces a counter example if it cannot prove a goal.
  3974    Note that the counter example may be spurious if the goal is not a formula
  3975    of quantifier-free linear arithmetic.
  3976    In ProofGeneral the counter example appears in the trace buffer.
  3977 
  3978  - Knows about div k and mod k where k is a numeral of type nat or int.
  3979 
  3980  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3981    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3982    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3983 
  3984 * simp's arithmetic capabilities have been enhanced a bit: it now
  3985 takes ~= in premises into account (by performing a case split);
  3986 
  3987 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3988 are distributed over a sum of terms;
  3989 
  3990 * New tactic "trans_tac" and method "trans" instantiate
  3991 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3992 "<=", "<" and "=").
  3993 
  3994 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3995 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3996 
  3997 * 'typedef' command has new option "open" to suppress the set
  3998 definition;
  3999 
  4000 * functions Min and Max on finite sets have been introduced (theory
  4001 Finite_Set);
  4002 
  4003 * attribute [symmetric] now works for relations as well; it turns
  4004 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4005 
  4006 * induct over a !!-quantified statement (say !!x1..xn):
  4007   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4008 
  4009 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4010 %x. None. Warning: empty_def now refers to the previously hidden definition
  4011 of the empty set.
  4012 
  4013 * Algebra: formalization of classical algebra.  Intended as base for
  4014 any algebraic development in Isabelle.  Currently covers group theory
  4015 (up to Sylow's theorem) and ring theory (Universal Property of
  4016 Univariate Polynomials).  Contributions welcome;
  4017 
  4018 * GroupTheory: deleted, since its material has been moved to Algebra;
  4019 
  4020 * Complex: new directory of the complex numbers with numeric constants,
  4021 nonstandard complex numbers, and some complex analysis, standard and
  4022 nonstandard (Jacques Fleuriot);
  4023 
  4024 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4025 
  4026 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4027 Fleuriot);
  4028 
  4029 * Real/HahnBanach: updated and adapted to locales;
  4030 
  4031 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4032 Gray and Kramer);
  4033 
  4034 * UNITY: added the Meier-Sanders theory of progress sets;
  4035 
  4036 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4037 as abstract algorithms, instantiated to the JVM;
  4038 
  4039 * Bali: Java source language formalization. Type system, operational
  4040 semantics, axiomatic semantics. Supported language features:
  4041 classes, interfaces, objects,virtual methods, static methods,
  4042 static/instance fields, arrays, access modifiers, definite
  4043 assignment, exceptions.
  4044 
  4045 
  4046 *** ZF ***
  4047 
  4048 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4049 universe, etc.);
  4050 
  4051 * Main ZF: virtually all theories converted to new-style format;
  4052 
  4053 
  4054 *** ML ***
  4055 
  4056 * Pure: Tactic.prove provides sane interface for internal proofs;
  4057 omits the infamous "standard" operation, so this is more appropriate
  4058 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4059 
  4060 * Pure: improved error reporting of simprocs;
  4061 
  4062 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4063 up simprocs;
  4064 
  4065 
  4066 *** Document preparation ***
  4067 
  4068 * uses \par instead of \\ for line breaks in theory text. This may
  4069 shift some page breaks in large documents. To get the old behaviour
  4070 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4071 
  4072 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4073 other packages
  4074 
  4075 * \<euro> now needs package babel/greek instead of marvosym (which
  4076 broke \Rightarrow)
  4077 
  4078 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4079 textcomp package)
  4080 
  4081 
  4082 
  4083 New in Isabelle2002 (March 2002)
  4084 --------------------------------
  4085 
  4086 *** Document preparation ***
  4087 
  4088 * greatly simplified document preparation setup, including more
  4089 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4090 instructive isatool mkdir; users should basically be able to get
  4091 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4092 users may run a separate document processing stage manually like this:
  4093 "isatool usedir -D output HOL Test && isatool document Test/output";
  4094 
  4095 * theory dependency graph may now be incorporated into documents;
  4096 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4097 with \includegraphics of LaTeX;
  4098 
  4099 * proper spacing of consecutive markup elements, especially text
  4100 blocks after section headings;
  4101 
  4102 * support bold style (for single symbols only), input syntax is like
  4103 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4104 
  4105 * \<bullet> is now output as bold \cdot by default, which looks much
  4106 better in printed text;
  4107 
  4108 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4109 note that these symbols are currently unavailable in Proof General /
  4110 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4111 
  4112 * isatool latex no longer depends on changed TEXINPUTS, instead
  4113 isatool document copies the Isabelle style files to the target
  4114 location;
  4115 
  4116 
  4117 *** Isar ***
  4118 
  4119 * Pure/Provers: improved proof by cases and induction;
  4120   - 'case' command admits impromptu naming of parameters (such as
  4121     "case (Suc n)");
  4122   - 'induct' method divinates rule instantiation from the inductive
  4123     claim; no longer requires excessive ?P bindings for proper
  4124     instantiation of cases;
  4125   - 'induct' method properly enumerates all possibilities of set/type
  4126     rules; as a consequence facts may be also passed through *type*
  4127     rules without further ado;
  4128   - 'induct' method now derives symbolic cases from the *rulified*
  4129     rule (before it used to rulify cases stemming from the internal
  4130     atomized version); this means that the context of a non-atomic
  4131     statement becomes is included in the hypothesis, avoiding the
  4132     slightly cumbersome show "PROP ?case" form;
  4133   - 'induct' may now use elim-style induction rules without chaining
  4134     facts, using ``missing'' premises from the goal state; this allows
  4135     rules stemming from inductive sets to be applied in unstructured
  4136     scripts, while still benefitting from proper handling of non-atomic
  4137     statements; NB: major inductive premises need to be put first, all
  4138     the rest of the goal is passed through the induction;
  4139   - 'induct' proper support for mutual induction involving non-atomic
  4140     rule statements (uses the new concept of simultaneous goals, see
  4141     below);
  4142   - append all possible rule selections, but only use the first
  4143     success (no backtracking);
  4144   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4145   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4146   - added 'print_induct_rules' (covered by help item in recent Proof
  4147     General versions);
  4148   - moved induct/cases attributes to Pure, methods to Provers;
  4149   - generic method setup instantiated for FOL and HOL;
  4150 
  4151 * Pure: support multiple simultaneous goal statements, for example
  4152 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4153 meta-level mechanism, this acts as if several individual goals had
  4154 been stated separately; in particular common proof methods need to be
  4155 repeated in order to cover all claims; note that a single elimination
  4156 step is *not* sufficient to establish the two conjunctions, so this
  4157 fails:
  4158 
  4159   assume "A & B" then have A and B ..   (*".." fails*)
  4160 
  4161 better use "obtain" in situations as above; alternative refer to
  4162 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4163 
  4164 * Pure: proper integration with ``locales''; unlike the original
  4165 version by Florian Kammller, Isar locales package high-level proof
  4166 contexts rather than raw logical ones (e.g. we admit to include
  4167 attributes everywhere); operations on locales include merge and
  4168 rename; support for implicit arguments (``structures''); simultaneous
  4169 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4170 some examples;
  4171 
  4172 * Pure: the following commands have been ``localized'', supporting a
  4173 target locale specification "(in name)": 'lemma', 'theorem',
  4174 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4175 stored both within the locale and at the theory level (exported and
  4176 qualified by the locale name);
  4177 
  4178 * Pure: theory goals may now be specified in ``long'' form, with
  4179 ad-hoc contexts consisting of arbitrary locale elements. for example
  4180 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4181 definitions may be given, too); the result is a meta-level rule with
  4182 the context elements being discharged in the obvious way;
  4183 
  4184 * Pure: new proof command 'using' allows to augment currently used
  4185 facts after a goal statement ('using' is syntactically analogous to
  4186 'apply', but acts on the goal's facts only); this allows chained facts
  4187 to be separated into parts given before and after a claim, as in
  4188 ``from a and b have C using d and e <proof>'';
  4189 
  4190 * Pure: renamed "antecedent" case to "rule_context";
  4191 
  4192 * Pure: new 'judgment' command records explicit information about the
  4193 object-logic embedding (used by several tools internally); no longer
  4194 use hard-wired "Trueprop";
  4195 
  4196 * Pure: added 'corollary' command;
  4197 
  4198 * Pure: fixed 'token_translation' command;
  4199 
  4200 * Pure: removed obsolete 'exported' attribute;
  4201 
  4202 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4203 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4204 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4205 
  4206 * Pure: method 'atomize' presents local goal premises as object-level
  4207 statements (atomic meta-level propositions); setup controlled via
  4208 rewrite rules declarations of 'atomize' attribute; example
  4209 application: 'induct' method with proper rule statements in improper
  4210 proof *scripts*;
  4211 
  4212 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4213 now consider the syntactic context of assumptions, giving a better
  4214 chance to get type-inference of the arguments right (this is
  4215 especially important for locales);
  4216 
  4217 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4218 mode;
  4219 
  4220 * Pure/obtain: the formal conclusion "thesis", being marked as
  4221 ``internal'', may no longer be reference directly in the text;
  4222 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4223 situations;
  4224 
  4225 * Pure: generic 'sym' attribute which declares a rule both as pure
  4226 'elim?' and for the 'symmetric' operation;
  4227 
  4228 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4229 text; the fixed correlation with particular command syntax has been
  4230 discontinued;
  4231 
  4232 * Pure: new method 'rules' is particularly well-suited for proof
  4233 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4234 but often produces more compact proof terms with less detours;
  4235 
  4236 * Pure/Provers/classical: simplified integration with pure rule
  4237 attributes and methods; the classical "intro?/elim?/dest?"
  4238 declarations coincide with the pure ones; the "rule" method no longer
  4239 includes classically swapped intros; "intro" and "elim" methods no
  4240 longer pick rules from the context; also got rid of ML declarations
  4241 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4242 INCOMPATIBILITY;
  4243 
  4244 * Provers/classical: attribute 'swapped' produces classical inversions
  4245 of introduction rules;
  4246 
  4247 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4248 rules instead of full simplifier context; 'iff' attribute handles
  4249 conditional rules;
  4250 
  4251 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4252 
  4253 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4254 "(permissive)" option to recover old behavior;
  4255 
  4256 * HOL: 'inductive' no longer features separate (collective) attributes
  4257 for 'intros' (was found too confusing);
  4258 
  4259 * HOL: properly declared induction rules less_induct and
  4260 wf_induct_rule;
  4261 
  4262 
  4263 *** HOL ***
  4264 
  4265 * HOL: moved over to sane numeral syntax; the new policy is as
  4266 follows:
  4267 
  4268   - 0 and 1 are polymorphic constants, which are defined on any
  4269   numeric type (nat, int, real etc.);
  4270 
  4271   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4272   binary representation internally;
  4273 
  4274   - type nat has special constructor Suc, and generally prefers Suc 0
  4275   over 1::nat and Suc (Suc 0) over 2::nat;
  4276 
  4277 This change may cause significant problems of INCOMPATIBILITY; here
  4278 are some hints on converting existing sources:
  4279 
  4280   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4281   entities, so expressions involving "-" (unary or binary minus) need
  4282   to be spaced properly;
  4283 
  4284   - existing occurrences of "1" may need to be constraint "1::nat" or
  4285   even replaced by Suc 0; similar for old "2";
  4286 
  4287   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4288 
  4289   - remove all special provisions on numerals in proofs;
  4290 
  4291 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4292 representation (depends on bin_arith_simps in the default context);
  4293 
  4294 * HOL: symbolic syntax for x^2 (numeral 2);
  4295 
  4296 * HOL: the class of all HOL types is now called "type" rather than
  4297 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4298 in axclass/classes, instance/arities, and (usually rare) occurrences
  4299 in typings (of consts etc.); internally the class is called
  4300 "HOL.type", ML programs should refer to HOLogic.typeS;
  4301 
  4302 * HOL/record package improvements:
  4303   - new derived operations "fields" to build a partial record section,
  4304     "extend" to promote a fixed record to a record scheme, and
  4305     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4306     declared as simp by default;
  4307   - shared operations ("more", "fields", etc.) now need to be always
  4308     qualified) --- potential INCOMPATIBILITY;
  4309   - removed "make_scheme" operations (use "make" with "extend") --
  4310     INCOMPATIBILITY;
  4311   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4312   - provides cases/induct rules for use with corresponding Isar
  4313     methods (for concrete records, record schemes, concrete more
  4314     parts, and schematic more parts -- in that order);
  4315   - internal definitions directly based on a light-weight abstract
  4316     theory of product types over typedef rather than datatype;
  4317 
  4318 * HOL: generic code generator for generating executable ML code from
  4319 specifications; specific support for HOL constructs such as inductive
  4320 datatypes and sets, as well as recursive functions; can be invoked
  4321 via 'generate_code' theory section;
  4322 
  4323 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4324 
  4325 * HOL: consolidated and renamed several theories.  In particular:
  4326         Ord.thy has been absorbed into HOL.thy
  4327         String.thy has been absorbed into List.thy
  4328 
  4329 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4330 (beware of argument permutation!);
  4331 
  4332 * HOL: linorder_less_split superseded by linorder_cases;
  4333 
  4334 * HOL/List: "nodups" renamed to "distinct";
  4335 
  4336 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4337 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4338   - Ex_def has changed, now need to use some_eq_ex
  4339 
  4340 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4341 in this (rare) case use:
  4342 
  4343   delSWrapper "split_all_tac"
  4344   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4345 
  4346 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4347 MAY FAIL;
  4348 
  4349 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4350 Isabelle's type classes, ^ on functions and relations has too general
  4351 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4352 necessary to attach explicit type constraints;
  4353 
  4354 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4355 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4356 renamed accordingly (eg "compI" -> "rel_compI").
  4357 
  4358 * HOL: syntax translations now work properly with numerals and records
  4359 expressions;
  4360 
  4361 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4362 of "lam" -- INCOMPATIBILITY;
  4363 
  4364 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4365 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4366 renamed "Product_Type.unit";
  4367 
  4368 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4369 
  4370 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4371 the "cases" method);
  4372 
  4373 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4374 Florian Kammller);
  4375 
  4376 * HOL/IMP: updated and converted to new-style theory format; several
  4377 parts turned into readable document, with proper Isar proof texts and
  4378 some explanations (by Gerwin Klein);
  4379 
  4380 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4381 
  4382 * HOL-Hyperreal is now a logic image;
  4383 
  4384 
  4385 *** HOLCF ***
  4386 
  4387 * Isar: consts/constdefs supports mixfix syntax for continuous
  4388 operations;
  4389 
  4390 * Isar: domain package adapted to new-style theory format, e.g. see
  4391 HOLCF/ex/Dnat.thy;
  4392 
  4393 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4394 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4395 lift.induct_tac, always use UU instead of Undef;
  4396 
  4397 * HOLCF/IMP: updated and converted to new-style theory;
  4398 
  4399 
  4400 *** ZF ***
  4401 
  4402 * Isar: proper integration of logic-specific tools and packages,
  4403 including theory commands '(co)inductive', '(co)datatype',
  4404 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4405 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4406 
  4407 * theory Main no longer includes AC; for the Axiom of Choice, base
  4408 your theory on Main_ZFC;
  4409 
  4410 * the integer library now covers quotients and remainders, with many
  4411 laws relating division to addition, multiplication, etc.;
  4412 
  4413 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4414 typeless version of the formalism;
  4415 
  4416 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4417 format;
  4418 
  4419 * ZF/Induct: new directory for examples of inductive definitions,
  4420 including theory Multiset for multiset orderings; converted to
  4421 new-style theory format;
  4422 
  4423 * ZF: many new theorems about lists, ordinals, etc.;
  4424 
  4425 
  4426 *** General ***
  4427 
  4428 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4429 variable proof controls level of detail: 0 = no proofs (only oracle
  4430 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4431 also ref manual for further ML interfaces;
  4432 
  4433 * Pure/axclass: removed obsolete ML interface
  4434 goal_subclass/goal_arity;
  4435 
  4436 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4437 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4438 separate tokens, so expressions involving minus need to be spaced
  4439 properly;
  4440 
  4441 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4442 rather than "infixl" or "infixr";
  4443 
  4444 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4445 sort constraint specifications in type inference; e.g. "x::_::foo"
  4446 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4447 type variable);
  4448 
  4449 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4450 control output of nested => (types); the default behavior is
  4451 "type_brackets";
  4452 
  4453 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4454 tokens into AST constants;
  4455 
  4456 * Pure/syntax: prefer later declarations of translations and print
  4457 translation functions; potential INCOMPATIBILITY: need to reverse
  4458 multiple declarations for same syntax element constant;
  4459 
  4460 * Pure/show_hyps reset by default (in accordance to existing Isar
  4461 practice);
  4462 
  4463 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4464 addSafter;
  4465 
  4466 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4467 as well;
  4468 
  4469 * system: tested support for MacOS X; should be able to get Isabelle +
  4470 Proof General to work in a plain Terminal after installing Poly/ML
  4471 (e.g. from the Isabelle distribution area) and GNU bash alone
  4472 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4473 support requires further installations, e.g. from
  4474 http://fink.sourceforge.net/);
  4475 
  4476 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4477 
  4478 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4479 of 40 MB), cf. ML_OPTIONS;
  4480 
  4481 * system: Proof General keywords specification is now part of the
  4482 Isabelle distribution (see etc/isar-keywords.el);
  4483 
  4484 * system: support for persistent Proof General sessions (refrain from
  4485 outdating all loaded theories on startup); user may create writable
  4486 logic images like this: ``isabelle -q HOL Test'';
  4487 
  4488 * system: smart selection of Isabelle process versus Isabelle
  4489 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4490 run both "isabelle" and "Isabelle" even if file names are badly
  4491 damaged (executable inspects the case of the first letter of its own
  4492 name); added separate "isabelle-process" and "isabelle-interface";
  4493 
  4494 * system: refrain from any attempt at filtering input streams; no
  4495 longer support ``8bit'' encoding of old isabelle font, instead proper
  4496 iso-latin characters may now be used; the related isatools
  4497 "symbolinput" and "nonascii" have disappeared as well;
  4498 
  4499 * system: removed old "xterm" interface (the print modes "xterm" and
  4500 "xterm_color" are still available for direct use in a suitable
  4501 terminal);
  4502 
  4503 
  4504 
  4505 New in Isabelle99-2 (February 2001)
  4506 -----------------------------------
  4507 
  4508 *** Overview of INCOMPATIBILITIES ***
  4509 
  4510 * HOL: please note that theories in the Library and elsewhere often use the
  4511 new-style (Isar) format; to refer to their theorems in an ML script you must
  4512 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4513 
  4514 * HOL: inductive package no longer splits induction rule aggressively,
  4515 but only as far as specified by the introductions given; the old
  4516 format may be recovered via ML function complete_split_rule or attribute
  4517 'split_rule (complete)';
  4518 
  4519 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4520 gfp_Tarski to gfp_unfold;
  4521 
  4522 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4523 
  4524 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4525 relation); infix "^^" has been renamed "``"; infix "``" has been
  4526 renamed "`"; "univalent" has been renamed "single_valued";
  4527 
  4528 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4529 operation;
  4530 
  4531 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4532 
  4533 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4534 
  4535 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4536 consequence, it is no longer monotonic wrt. the local goal context
  4537 (which is now passed through the inductive cases);
  4538 
  4539 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4540 \<gg> to \<ggreater>;
  4541 
  4542 
  4543 *** Document preparation ***
  4544 
  4545 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4546 available: are "it" for near math-mode best-style output, "sl" for
  4547 slanted text style, and "tt" for plain type-writer; if no
  4548 \isabellestyle command is given, output is according to slanted
  4549 type-writer);
  4550 
  4551 * support sub/super scripts (for single symbols only), input syntax is
  4552 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4553 
  4554 * some more standard symbols; see Appendix A of the system manual for
  4555 the complete list of symbols defined in isabellesym.sty;
  4556 
  4557 * improved isabelle style files; more abstract symbol implementation
  4558 (should now use \isamath{...} and \isatext{...} in custom symbol
  4559 definitions);
  4560 
  4561 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4562 state; Note that presentation of goal states does not conform to
  4563 actual human-readable proof documents.  Please do not include goal
  4564 states into document output unless you really know what you are doing!
  4565 
  4566 * proper indentation of antiquoted output with proportional LaTeX
  4567 fonts;
  4568 
  4569 * no_document ML operator temporarily disables LaTeX document
  4570 generation;
  4571 
  4572 * isatool unsymbolize tunes sources for plain ASCII communication;
  4573 
  4574 
  4575 *** Isar ***
  4576 
  4577 * Pure: Isar now suffers initial goal statements to contain unbound
  4578 schematic variables (this does not conform to actual readable proof
  4579 documents, due to unpredictable outcome and non-compositional proof
  4580 checking); users who know what they are doing may use schematic goals
  4581 for Prolog-style synthesis of proven results;
  4582 
  4583 * Pure: assumption method (an implicit finishing) now handles actual
  4584 rules as well;
  4585 
  4586 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4587 initial goal, declare "that" only as Pure intro (only for single
  4588 steps); the "that" rule assumption may now be involved in implicit
  4589 finishing, thus ".." becomes a feasible for trivial obtains;
  4590 
  4591 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4592 instance proofs may be performed by "..";
  4593 
  4594 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4595 statements as well;
  4596 
  4597 * Pure: more robust selection of calculational rules;
  4598 
  4599 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4600 rule (as well as the assumption rule);
  4601 
  4602 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4603 lemmas, using the graph browser tool;
  4604 
  4605 * Pure: predict failure of "show" in interactive mode;
  4606 
  4607 * Pure: 'thms_containing' now takes actual terms as arguments;
  4608 
  4609 * HOL: improved method 'induct' --- now handles non-atomic goals
  4610 (potential INCOMPATIBILITY); tuned error handling;
  4611 
  4612 * HOL: cases and induct rules now provide explicit hints about the
  4613 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4614 any remaining facts are inserted into the goal verbatim;
  4615 
  4616 * HOL: local contexts (aka cases) may now contain term bindings as
  4617 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4618 the result to be shown in each case;
  4619 
  4620 * HOL: added 'recdef_tc' command;
  4621 
  4622 * isatool convert assists in eliminating legacy ML scripts;
  4623 
  4624 
  4625 *** HOL ***
  4626 
  4627 * HOL/Library: a collection of generic theories to be used together
  4628 with main HOL; the theory loader path already includes this directory
  4629 by default; the following existing theories have been moved here:
  4630 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4631 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4632 
  4633 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4634 modelling and verification task performed in Isabelle/HOL +
  4635 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4636 
  4637 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4638 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4639 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4640 'domain', this makes the theory consistent with mathematical
  4641 literature;
  4642 
  4643 * HOL basics: added overloaded operations "inverse" and "divide"
  4644 (infix "/"), syntax for generic "abs" operation, generic summation
  4645 operator \<Sum>;
  4646 
  4647 * HOL/typedef: simplified package, provide more useful rules (see also
  4648 HOL/subset.thy);
  4649 
  4650 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4651 now expressed as a proper nested rule (old-style tactic scripts may
  4652 require atomize_strip_tac to cope with non-atomic premises);
  4653 
  4654 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4655 to "split_conv" (old name still available for compatibility);
  4656 
  4657 * HOL: improved concrete syntax for strings (e.g. allows translation
  4658 rules with string literals);
  4659 
  4660 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4661  and Fleuriot's mechanization of analysis, including the transcendental
  4662  functions for the reals;
  4663 
  4664 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4665 
  4666 
  4667 *** CTT ***
  4668 
  4669 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4670 "lam" is displayed as TWO lambda-symbols
  4671 
  4672 * CTT: theory Main now available, containing everything (that is, Bool
  4673 and Arith);
  4674 
  4675 
  4676 *** General ***
  4677 
  4678 * Pure: the Simplifier has been implemented properly as a derived rule
  4679 outside of the actual kernel (at last!); the overall performance
  4680 penalty in practical applications is about 50%, while reliability of
  4681 the Isabelle inference kernel has been greatly improved;
  4682 
  4683 * print modes "brackets" and "no_brackets" control output of nested =>
  4684 (types) and ==> (props); the default behaviour is "brackets";
  4685 
  4686 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4687 as assumptions as well;
  4688 
  4689 * system: support Poly/ML 4.0;
  4690 
  4691 * system: isatool install handles KDE version 1 or 2;
  4692 
  4693 
  4694 
  4695 New in Isabelle99-1 (October 2000)
  4696 ----------------------------------
  4697 
  4698 *** Overview of INCOMPATIBILITIES ***
  4699 
  4700 * HOL: simplification of natural numbers is much changed; to partly
  4701 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4702 issue the following ML commands:
  4703 
  4704   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4705   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4706 
  4707 * HOL: simplification no longer dives into case-expressions; this is
  4708 controlled by "t.weak_case_cong" for each datatype t;
  4709 
  4710 * HOL: nat_less_induct renamed to less_induct;
  4711 
  4712 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4713 fixsome to patch .thy and .ML sources automatically;
  4714 
  4715   select_equality  -> some_equality
  4716   select_eq_Ex     -> some_eq_ex
  4717   selectI2EX       -> someI2_ex
  4718   selectI2         -> someI2
  4719   selectI          -> someI
  4720   select1_equality -> some1_equality
  4721   Eps_sym_eq       -> some_sym_eq_trivial
  4722   Eps_eq           -> some_eq_trivial
  4723 
  4724 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4725 
  4726 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4727 instead);
  4728 
  4729 * HOL: the recursion equations generated by 'recdef' are now called
  4730 f.simps instead of f.rules;
  4731 
  4732 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4733 
  4734 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4735 sometimes be needed;
  4736 
  4737 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4738 
  4739 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4740 
  4741 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4742 product is now "<*>" instead of "Times"; the lexicographic product is
  4743 now "<*lex*>" instead of "**";
  4744 
  4745 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4746 of main HOL, but was unused); better use HOL's datatype package;
  4747 
  4748 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4749 the old syntax may be recovered as follows:
  4750 
  4751   syntax (symbols)
  4752     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4753       (infixl "\\<oplus>" 100)
  4754 
  4755 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4756 
  4757 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4758 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4759 internally;
  4760 
  4761 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4762 changed from A/r to A//r;
  4763 
  4764 * ZF: new treatment of arithmetic (nat & int) may break some old
  4765 proofs;
  4766 
  4767 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4768 rulify -> rule_format, elimify -> elim_format, ...);
  4769 
  4770 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4771 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4772 should have to change intro!! to intro? only); replaced "delrule" by
  4773 "rule del";
  4774 
  4775 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4776 
  4777 * Provers: strengthened force_tac by using new first_best_tac;
  4778 
  4779 * LaTeX document preparation: several changes of isabelle.sty (see
  4780 lib/texinputs);
  4781 
  4782 
  4783 *** Document preparation ***
  4784 
  4785 * formal comments (text blocks etc.) in new-style theories may now
  4786 contain antiquotations of thm/prop/term/typ/text to be presented
  4787 according to latex print mode; concrete syntax is like this:
  4788 @{term[show_types] "f(x) = a + x"};
  4789 
  4790 * isatool mkdir provides easy setup of Isabelle session directories,
  4791 including proper document sources;
  4792 
  4793 * generated LaTeX sources are now deleted after successful run
  4794 (isatool document -c); may retain a copy somewhere else via -D option
  4795 of isatool usedir;
  4796 
  4797 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4798 style files, achieving self-contained LaTeX sources and simplifying
  4799 LaTeX debugging;
  4800 
  4801 * old-style theories now produce (crude) LaTeX output as well;
  4802 
  4803 * browser info session directories are now self-contained (may be put
  4804 on WWW server seperately); improved graphs of nested sessions; removed
  4805 graph for 'all sessions';
  4806 
  4807 * several improvements in isabelle style files; \isabellestyle{it}
  4808 produces fake math mode output; \isamarkupheader is now \section by
  4809 default; see lib/texinputs/isabelle.sty etc.;
  4810 
  4811 
  4812 *** Isar ***
  4813 
  4814 * Isar/Pure: local results and corresponding term bindings are now
  4815 subject to Hindley-Milner polymorphism (similar to ML); this
  4816 accommodates incremental type-inference very nicely;
  4817 
  4818 * Isar/Pure: new derived language element 'obtain' supports
  4819 generalized existence reasoning;
  4820 
  4821 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4822 support accumulation of results, without applying any rules yet;
  4823 useful to collect intermediate results without explicit name
  4824 references, and for use with transitivity rules with more than 2
  4825 premises;
  4826 
  4827 * Isar/Pure: scalable support for case-analysis type proofs: new
  4828 'case' language element refers to local contexts symbolically, as
  4829 produced by certain proof methods; internally, case names are attached
  4830 to theorems as "tags";
  4831 
  4832 * Isar/Pure: theory command 'hide' removes declarations from
  4833 class/type/const name spaces;
  4834 
  4835 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4836 indicate potential overloading;
  4837 
  4838 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4839 
  4840 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4841 "{a,b,c}" instead of {a,b,c};
  4842 
  4843 * Isar/Pure now provides its own version of intro/elim/dest
  4844 attributes; useful for building new logics, but beware of confusion
  4845 with the version in Provers/classical;
  4846 
  4847 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4848 case name 'antecedent';
  4849 
  4850 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4851 to the current context is now done automatically);
  4852 
  4853 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4854 for definining proof methods in ML;
  4855 
  4856 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4857 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4858 most cases, one should have to change intro!! to intro? only);
  4859 replaced "delrule" by "rule del";
  4860 
  4861 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4862 'symmetric' attribute (the latter supercedes [RS sym]);
  4863 
  4864 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4865 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4866 well (including splits);
  4867 
  4868 * Isar/Provers: Simplifier and Classical methods now support all kind
  4869 of modifiers used in the past, including 'cong', 'iff', etc.
  4870 
  4871 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4872 of Simplifier and Classical reasoner);
  4873 
  4874 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4875 now support named cases; major packages (inductive, datatype, primrec,
  4876 recdef) support case names and properly name parameters;
  4877 
  4878 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4879 monotonicity conditions are extracted to be proven at end of
  4880 calculations;
  4881 
  4882 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4883 method anyway;
  4884 
  4885 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4886 split_if split_if_asm; datatype package provides theorems foo.splits =
  4887 foo.split foo.split_asm for each datatype;
  4888 
  4889 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4890 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4891 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4892 use "(cases (simplified))" method in proper proof texts);
  4893 
  4894 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4895 
  4896 * Isar: names of theorems etc. may be natural numbers as well;
  4897 
  4898 * Isar: 'pr' command: optional arguments for goals_limit and
  4899 ProofContext.prems_limit; no longer prints theory contexts, but only
  4900 proof states;
  4901 
  4902 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4903 additional print modes to be specified; e.g. "pr(latex)" will print
  4904 proof state according to the Isabelle LaTeX style;
  4905 
  4906 * Isar: improved support for emulating tactic scripts, including proof
  4907 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4908 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4909 (for HOL datatypes);
  4910 
  4911 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4912 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4913 'proof method scripts' have to be in depth-first order;
  4914 
  4915 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4916 
  4917 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4918 should instead use individual commands for printing items
  4919 (print_commands, print_methods etc.);
  4920 
  4921 * Isar: added 'nothing' --- the empty list of theorems;
  4922 
  4923 
  4924 *** HOL ***
  4925 
  4926 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4927 corresponding virtual machine and a specification of its bytecode
  4928 verifier and a lightweight bytecode verifier, including proofs of
  4929 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4930 Cornelia Pusch (see also the homepage of project Bali at
  4931 http://isabelle.in.tum.de/Bali/);
  4932 
  4933 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4934 Clemens Ballarin;
  4935 
  4936 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4937 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4938 Rasmussen;
  4939 
  4940 * HOL/Lattice: fundamental concepts of lattice theory and order
  4941 structures, including duals, properties of bounds versus algebraic
  4942 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4943 Theorem for complete lattices etc.; may also serve as a demonstration
  4944 for abstract algebraic reasoning using axiomatic type classes, and
  4945 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4946 
  4947 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4948 von Oheimb;
  4949 
  4950 * HOL/IMPP: extension of IMP with local variables and mutually
  4951 recursive procedures, by David von Oheimb;
  4952 
  4953 * HOL/Lambda: converted into new-style theory and document;
  4954 
  4955 * HOL/ex/Multiquote: example of multiple nested quotations and
  4956 anti-quotations -- basically a generalized version of de-Bruijn
  4957 representation; very useful in avoiding lifting of operations;
  4958 
  4959 * HOL/record: added general record equality rule to simpset; fixed
  4960 select-update simplification procedure to handle extended records as
  4961 well; admit "r" as field name;
  4962 
  4963 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4964 other numeric types and also as the identity of groups, rings, etc.;
  4965 
  4966 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4967 Types nat and int belong to this axclass;
  4968 
  4969 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4970    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4971    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4972   two terms #m*u and #n*u are replaced by #(m+n)*u
  4973     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4974   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4975     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4976 
  4977 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4978 powerful prover for predicate logic but knows nothing of clasets; see
  4979 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4980 
  4981 * HOL: new version of "case_tac" subsumes both boolean case split and
  4982 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4983 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4984 
  4985 * HOL: simplification no longer dives into case-expressions: only the
  4986 selector expression is simplified, but not the remaining arms; to
  4987 enable full simplification of case-expressions for datatype t, you may
  4988 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4989 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4990 
  4991 * HOL/recdef: the recursion equations generated by 'recdef' for
  4992 function 'f' are now called f.simps instead of f.rules; if all
  4993 termination conditions are proved automatically, these simplification
  4994 rules are added to the simpset, as in primrec; rules may be named
  4995 individually as well, resulting in a separate list of theorems for
  4996 each equation;
  4997 
  4998 * HOL/While is a new theory that provides a while-combinator. It
  4999 permits the definition of tail-recursive functions without the
  5000 provision of a termination measure. The latter is necessary once the
  5001 invariant proof rule for while is applied.
  5002 
  5003 * HOL: new (overloaded) notation for the set of elements below/above
  5004 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5005 
  5006 * HOL: theorems impI, allI, ballI bound as "strip";
  5007 
  5008 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5009 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5010 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5011 
  5012 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5013 
  5014 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5015 main HOL, but was unused);
  5016 
  5017 * HOL: fewer consts declared as global (e.g. have to refer to
  5018 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5019 
  5020 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5021 in case of overlap with user translations (e.g. judgements over
  5022 tuples); (note that the underlying logical represenation is still
  5023 bogus);
  5024 
  5025 
  5026 *** ZF ***
  5027 
  5028 * ZF: simplification automatically cancels common terms in arithmetic
  5029 expressions over nat and int;
  5030 
  5031 * ZF: new treatment of nat to minimize type-checking: all operators
  5032 coerce their operands to a natural number using the function natify,
  5033 making the algebraic laws unconditional;
  5034 
  5035 * ZF: as above, for int: operators coerce their operands to an integer
  5036 using the function intify;
  5037 
  5038 * ZF: the integer library now contains many of the usual laws for the
  5039 orderings, including $<=, and monotonicity laws for $+ and $*;
  5040 
  5041 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5042 simplification;
  5043 
  5044 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5045 to the simplifier and classical reasoner simultaneously;
  5046 
  5047 
  5048 *** General ***
  5049 
  5050 * Provers: blast_tac now handles actual object-logic rules as
  5051 assumptions; note that auto_tac uses blast_tac internally as well;
  5052 
  5053 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5054 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5055 
  5056 * Provers: delrules now handles destruct rules as well (no longer need
  5057 explicit make_elim);
  5058 
  5059 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5060   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5061 use instead the strong form,
  5062   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5063 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5064 from destruct-rules;
  5065 
  5066 * Provers: Simplifier.easy_setup provides a fast path to basic
  5067 Simplifier setup for new object-logics;
  5068 
  5069 * Pure: AST translation rules no longer require constant head on LHS;
  5070 
  5071 * Pure: improved name spaces: ambiguous output is qualified; support
  5072 for hiding of names;
  5073 
  5074 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5075 XSYMBOL_HOME; no longer need to do manual configuration in most
  5076 situations;
  5077 
  5078 * system: compression of ML heaps images may now be controlled via -c
  5079 option of isabelle and isatool usedir (currently only observed by
  5080 Poly/ML);
  5081 
  5082 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5083 useful for remote X11);
  5084 
  5085 * system: provide TAGS file for Isabelle sources;
  5086 
  5087 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5088 order;
  5089 
  5090 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5091 timing flag supersedes proof_timing and Toplevel.trace;
  5092 
  5093 * ML: new combinators |>> and |>>> for incremental transformations
  5094 with secondary results (e.g. certain theory extensions):
  5095 
  5096 * ML: PureThy.add_defs gets additional argument to indicate potential
  5097 overloading (usually false);
  5098 
  5099 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5100 results;
  5101 
  5102 
  5103 
  5104 New in Isabelle99 (October 1999)
  5105 --------------------------------
  5106 
  5107 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5108 
  5109 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5110 are no longer simplified.  (This allows the simplifier to unfold recursive
  5111 functional programs.)  To restore the old behaviour, declare
  5112 
  5113     Delcongs [if_weak_cong];
  5114 
  5115 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5116 complement;
  5117 
  5118 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5119 
  5120 * HOL/datatype: mutual_induct_tac no longer exists --
  5121   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5122 
  5123 * HOL/typedef: fixed type inference for representing set; type
  5124 arguments now have to occur explicitly on the rhs as type constraints;
  5125 
  5126 * ZF: The con_defs part of an inductive definition may no longer refer
  5127 to constants declared in the same theory;
  5128 
  5129 * HOL, ZF: the function mk_cases, generated by the inductive
  5130 definition package, has lost an argument.  To simplify its result, it
  5131 uses the default simpset instead of a supplied list of theorems.
  5132 
  5133 * HOL/List: the constructors of type list are now Nil and Cons;
  5134 
  5135 * Simplifier: the type of the infix ML functions
  5136         setSSolver addSSolver setSolver addSolver
  5137 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5138 for packaging solvers. A solver is created via
  5139         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5140 where the string argument is only a comment.
  5141 
  5142 
  5143 *** Proof tools ***
  5144 
  5145 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5146 decision procedure for linear arithmetic. Currently it is used for
  5147 types `nat', `int', and `real' in HOL (see below); it can, should and
  5148 will be instantiated for other types and logics as well.
  5149 
  5150 * The simplifier now accepts rewrite rules with flexible heads, eg
  5151      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5152   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5153   matching.
  5154 
  5155 
  5156 *** General ***
  5157 
  5158 * New Isabelle/Isar subsystem provides an alternative to traditional
  5159 tactical theorem proving; together with the ProofGeneral/isar user
  5160 interface it offers an interactive environment for developing human
  5161 readable proof documents (Isar == Intelligible semi-automated
  5162 reasoning); for further information see isatool doc isar-ref,
  5163 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5164 
  5165 * improved and simplified presentation of theories: better HTML markup
  5166 (including colors), graph views in several sizes; isatool usedir now
  5167 provides a proper interface for user theories (via -P option); actual
  5168 document preparation based on (PDF)LaTeX is available as well (for
  5169 new-style theories only); see isatool doc system for more information;
  5170 
  5171 * native support for Proof General, both for classic Isabelle and
  5172 Isabelle/Isar;
  5173 
  5174 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5175 using the graph browser tool;
  5176 
  5177 * Isabelle manuals now also available as PDF;
  5178 
  5179 * theory loader rewritten from scratch (may not be fully
  5180 bug-compatible); old loadpath variable has been replaced by show_path,
  5181 add_path, del_path, reset_path functions; new operations such as
  5182 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5183 isatool doc ref);
  5184 
  5185 * improved isatool install: option -k creates KDE application icon,
  5186 option -p DIR installs standalone binaries;
  5187 
  5188 * added ML_PLATFORM setting (useful for cross-platform installations);
  5189 more robust handling of platform specific ML images for SML/NJ;
  5190 
  5191 * the settings environment is now statically scoped, i.e. it is never
  5192 created again in sub-processes invoked from isabelle, isatool, or
  5193 Isabelle;
  5194 
  5195 * path element specification '~~' refers to '$ISABELLE_HOME';
  5196 
  5197 * in locales, the "assumes" and "defines" parts may be omitted if
  5198 empty;
  5199 
  5200 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5201 long arrows);
  5202 
  5203 * new print_mode "HTML";
  5204 
  5205 * new flag show_tags controls display of tags of theorems (which are
  5206 basically just comments that may be attached by some tools);
  5207 
  5208 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5209 mode and goal output format:
  5210 
  5211 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5212 244c244
  5213 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5214 ---
  5215 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5216 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5217 181c181
  5218 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5219 ---
  5220 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5221 
  5222 * function bind_thms stores lists of theorems (cf. bind_thm);
  5223 
  5224 * new shorthand tactics ftac, eatac, datac, fatac;
  5225 
  5226 * qed (and friends) now accept "" as result name; in that case the
  5227 theorem is not stored, but proper checks and presentation of the
  5228 result still apply;
  5229 
  5230 * theorem database now also indexes constants "Trueprop", "all",
  5231 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5232 
  5233 
  5234 *** HOL ***
  5235 
  5236 ** HOL arithmetic **
  5237 
  5238 * There are now decision procedures for linear arithmetic over nat and
  5239 int:
  5240 
  5241 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5242 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5243 are treated as atomic; subformulae not involving type `nat' or `int'
  5244 are ignored; quantified subformulae are ignored unless they are
  5245 positive universal or negative existential. The tactic has to be
  5246 invoked by hand and can be a little bit slow. In particular, the
  5247 running time is exponential in the number of occurrences of `min' and
  5248 `max', and `-' on `nat'.
  5249 
  5250 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5251 (negated) (in)equalities among the premises and the conclusion into
  5252 account (i.e. no compound formulae) and does not know about `min' and
  5253 `max', and `-' on `nat'. It is fast and is used automatically by the
  5254 simplifier.
  5255 
  5256 NB: At the moment, these decision procedures do not cope with mixed
  5257 nat/int formulae where the two parts interact, such as `m < n ==>
  5258 int(m) < int(n)'.
  5259 
  5260 * HOL/Numeral provides a generic theory of numerals (encoded
  5261 efficiently as bit strings); setup for types nat/int/real is in place;
  5262 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5263 int, existing theories and proof scripts may require a few additional
  5264 type constraints;
  5265 
  5266 * integer division and remainder can now be performed on constant
  5267 arguments;
  5268 
  5269 * many properties of integer multiplication, division and remainder
  5270 are now available;
  5271 
  5272 * An interface to the Stanford Validity Checker (SVC) is available through the
  5273 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5274 are proved automatically.  SVC must be installed separately, and its results
  5275 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5276 invocation of the underlying oracle).  For SVC see
  5277   http://verify.stanford.edu/SVC
  5278 
  5279 * IsaMakefile: the HOL-Real target now builds an actual image;
  5280 
  5281 
  5282 ** HOL misc **
  5283 
  5284 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5285 (in Isabelle/Isar) -- by Gertrud Bauer;
  5286 
  5287 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5288 analysis for assembly languages with subtypes;
  5289 
  5290 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5291 -- avoids syntactic ambiguities and treats state, transition, and
  5292 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5293 changed syntax and (many) tactics;
  5294 
  5295 * HOL/inductive: Now also handles more general introduction rules such
  5296   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5297   theorems are now maintained within the theory (maintained via the
  5298   "mono" attribute);
  5299 
  5300 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5301   (using function types) such as
  5302 
  5303   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5304 
  5305 * HOL/record: record_simproc (part of the default simpset) takes care
  5306 of selectors applied to updated records; record_split_tac is no longer
  5307 part of the default claset; update_defs may now be removed from the
  5308 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5309 
  5310   claset_ref () := claset() addSWrapper record_split_wrapper;
  5311   Delsimprocs [record_simproc]
  5312 
  5313 * HOL/typedef: fixed type inference for representing set; type
  5314 arguments now have to occur explicitly on the rhs as type constraints;
  5315 
  5316 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5317 names rather than an ML expression;
  5318 
  5319 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5320 supplied later.  Program schemes can be defined, such as
  5321     "While B C s = (if B s then While B C (C s) else s)"
  5322 where the well-founded relation can be chosen after B and C have been given.
  5323 
  5324 * HOL/List: the constructors of type list are now Nil and Cons;
  5325 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5326 course, ML tools referring to List.list.op # etc. have to be adapted;
  5327 
  5328 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5329 disabled by default; run isabelle with option -m HOL to get back to
  5330 the original Gordon/HOL-style output;
  5331 
  5332 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5333 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5334 
  5335 * HOL basic syntax simplified (more orthogonal): all variants of
  5336 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5337 Eps operator is provided as well: "SOME x. P[x]";
  5338 
  5339 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5340 
  5341 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5342 thus available for user theories;
  5343 
  5344 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5345 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5346 time;
  5347 
  5348 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5349 several times and then mp;
  5350 
  5351 
  5352 *** LK ***
  5353 
  5354 * the notation <<...>> is now available as a notation for sequences of
  5355 formulas;
  5356 
  5357 * the simplifier is now installed
  5358 
  5359 * the axiom system has been generalized (thanks to Soren Heilmann)
  5360 
  5361 * the classical reasoner now has a default rule database
  5362 
  5363 
  5364 *** ZF ***
  5365 
  5366 * new primrec section allows primitive recursive functions to be given
  5367 directly (as in HOL) over datatypes and the natural numbers;
  5368 
  5369 * new tactics induct_tac and exhaust_tac for induction (or case
  5370 analysis) over datatypes and the natural numbers;
  5371 
  5372 * the datatype declaration of type T now defines the recursor T_rec;
  5373 
  5374 * simplification automatically does freeness reasoning for datatype
  5375 constructors;
  5376 
  5377 * automatic type-inference, with AddTCs command to insert new
  5378 type-checking rules;
  5379 
  5380 * datatype introduction rules are now added as Safe Introduction rules
  5381 to the claset;
  5382 
  5383 * the syntax "if P then x else y" is now available in addition to
  5384 if(P,x,y);
  5385 
  5386 
  5387 *** Internal programming interfaces ***
  5388 
  5389 * tuned simplifier trace output; new flag debug_simp;
  5390 
  5391 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5392 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5393 
  5394 * AxClass.axclass_tac lost the theory argument;
  5395 
  5396 * tuned current_goals_markers semantics: begin / end goal avoids
  5397 printing empty lines;
  5398 
  5399 * removed prs and prs_fn hook, which was broken because it did not
  5400 include \n in its semantics, forcing writeln to add one
  5401 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5402 string -> unit if you really want to output text without newline;
  5403 
  5404 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5405 plain output, interface builders may have to enable 'isabelle_font'
  5406 mode to get Isabelle font glyphs as before;
  5407 
  5408 * refined token_translation interface; INCOMPATIBILITY: output length
  5409 now of type real instead of int;
  5410 
  5411 * theory loader actions may be traced via new ThyInfo.add_hook
  5412 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5413 your own database of information attached to *whole* theories -- as
  5414 opposed to intra-theory data slots offered via TheoryDataFun;
  5415 
  5416 * proper handling of dangling sort hypotheses (at last!);
  5417 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5418 extra sort hypotheses that can be witnessed from the type signature;
  5419 the force_strip_shyps flag is gone, any remaining shyps are simply
  5420 left in the theorem (with a warning issued by strip_shyps_warning);
  5421 
  5422 
  5423 
  5424 New in Isabelle98-1 (October 1998)
  5425 ----------------------------------
  5426 
  5427 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5428 
  5429 * several changes of automated proof tools;
  5430 
  5431 * HOL: major changes to the inductive and datatype packages, including
  5432 some minor incompatibilities of theory syntax;
  5433 
  5434 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5435 called `inj_on';
  5436 
  5437 * HOL: removed duplicate thms in Arith:
  5438   less_imp_add_less  should be replaced by  trans_less_add1
  5439   le_imp_add_le      should be replaced by  trans_le_add1
  5440 
  5441 * HOL: unary minus is now overloaded (new type constraints may be
  5442 required);
  5443 
  5444 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5445 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5446 now taken as an integer constant.
  5447 
  5448 * Pure: ML function 'theory_of' renamed to 'theory';
  5449 
  5450 
  5451 *** Proof tools ***
  5452 
  5453 * Simplifier:
  5454   1. Asm_full_simp_tac is now more aggressive.
  5455      1. It will sometimes reorient premises if that increases their power to
  5456         simplify.
  5457      2. It does no longer proceed strictly from left to right but may also
  5458         rotate premises to achieve further simplification.
  5459      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5460      old Asm_full_simp_tac in that it does not rotate premises.
  5461   2. The simplifier now knows a little bit about nat-arithmetic.
  5462 
  5463 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5464 allows for selected deletion of wrappers, by introduction of names for
  5465 wrapper functionals.  This implies that addbefore, addSbefore,
  5466 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5467 and that adding two tactics with the same name overwrites the first
  5468 one (emitting a warning).
  5469   type wrapper = (int -> tactic) -> (int -> tactic)
  5470   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5471   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5472   delWrapper, delSWrapper: claset *  string            -> claset
  5473   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5474 
  5475 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5476 semantics; addbefore now affects only the unsafe part of step_tac
  5477 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5478 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5479 by Force_tac;
  5480 
  5481 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5482 compWrapper; added safe wrapper (and access functions for it);
  5483 
  5484 * HOL/split_all_tac is now much faster and fails if there is nothing
  5485 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5486 and the names of the automatically generated variables have changed.
  5487 split_all_tac has moved within claset() from unsafe wrappers to safe
  5488 wrappers, which means that !!-bound variables are split much more
  5489 aggressively, and safe_tac and clarify_tac now split such variables.
  5490 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5491 Note: the same holds for record_split_tac, which does the job of
  5492 split_all_tac for record fields.
  5493 
  5494 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5495 permanently to the default simpset using Addsplits just like
  5496 Addsimps. They can be removed via Delsplits just like
  5497 Delsimps. Lower-case versions are also available.
  5498 
  5499 * HOL/Simplifier: The rule split_if is now part of the default
  5500 simpset. This means that the simplifier will eliminate all occurrences
  5501 of if-then-else in the conclusion of a goal. To prevent this, you can
  5502 either remove split_if completely from the default simpset by
  5503 `Delsplits [split_if]' or remove it in a specific call of the
  5504 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5505 other case splitting rules to/from the default simpset: every datatype
  5506 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5507 t is the name of the datatype).
  5508 
  5509 * Classical reasoner / Simplifier combination: new force_tac (and
  5510 derivatives Force_tac, force) combines rewriting and classical
  5511 reasoning (and whatever other tools) similarly to auto_tac, but is
  5512 aimed to solve the given subgoal completely.
  5513 
  5514 
  5515 *** General ***
  5516 
  5517 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5518 and `goalw': the theory is no longer needed as an explicit argument -
  5519 the current theory context is used; assumptions are no longer returned
  5520 at the ML-level unless one of them starts with ==> or !!; it is
  5521 recommended to convert to these new commands using isatool fixgoal
  5522 (backup your sources first!);
  5523 
  5524 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5525 the current theory context, and 'theory' to lookup stored theories;
  5526 
  5527 * new theory section 'locale' for declaring constants, assumptions and
  5528 definitions that have local scope;
  5529 
  5530 * new theory section 'nonterminals' for purely syntactic types;
  5531 
  5532 * new theory section 'setup' for generic ML setup functions
  5533 (e.g. package initialization);
  5534 
  5535 * the distribution now includes Isabelle icons: see
  5536 lib/logo/isabelle-{small,tiny}.xpm;
  5537 
  5538 * isatool install - install binaries with absolute references to
  5539 ISABELLE_HOME/bin;
  5540 
  5541 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5542 
  5543 * print mode 'emacs' reserved for Isamode;
  5544 
  5545 * support multiple print (ast) translations per constant name;
  5546 
  5547 * theorems involving oracles are now printed with a suffixed [!];
  5548 
  5549 
  5550 *** HOL ***
  5551 
  5552 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5553 
  5554 * HOL/inductive package reorganized and improved: now supports mutual
  5555 definitions such as
  5556 
  5557   inductive EVEN ODD
  5558     intrs
  5559       null "0 : EVEN"
  5560       oddI "n : EVEN ==> Suc n : ODD"
  5561       evenI "n : ODD ==> Suc n : EVEN"
  5562 
  5563 new theorem list "elims" contains an elimination rule for each of the
  5564 recursive sets; inductive definitions now handle disjunctive premises
  5565 correctly (also ZF);
  5566 
  5567 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5568 "mutual_induct" no longer exists - the induction rule is always
  5569 contained in "induct";
  5570 
  5571 
  5572 * HOL/datatype package re-implemented and greatly improved: now
  5573 supports mutually recursive datatypes such as
  5574 
  5575   datatype
  5576     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5577             | SUM ('a aexp) ('a aexp)
  5578             | DIFF ('a aexp) ('a aexp)
  5579             | NUM 'a
  5580   and
  5581     'a bexp = LESS ('a aexp) ('a aexp)
  5582             | AND ('a bexp) ('a bexp)
  5583             | OR ('a bexp) ('a bexp)
  5584 
  5585 as well as indirectly recursive datatypes such as
  5586 
  5587   datatype
  5588     ('a, 'b) term = Var 'a
  5589                   | App 'b ((('a, 'b) term) list)
  5590 
  5591 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5592 induction on mutually / indirectly recursive datatypes.
  5593 
  5594 Primrec equations are now stored in theory and can be accessed via
  5595 <function_name>.simps.
  5596 
  5597 INCOMPATIBILITIES:
  5598 
  5599   - Theories using datatypes must now have theory Datatype as an
  5600     ancestor.
  5601   - The specific <typename>.induct_tac no longer exists - use the
  5602     generic induct_tac instead.
  5603   - natE has been renamed to nat.exhaust - use exhaust_tac
  5604     instead of res_inst_tac ... natE. Note that the variable
  5605     names in nat.exhaust differ from the names in natE, this
  5606     may cause some "fragile" proofs to fail.
  5607   - The theorems split_<typename>_case and split_<typename>_case_asm
  5608     have been renamed to <typename>.split and <typename>.split_asm.
  5609   - Since default sorts of type variables are now handled correctly,
  5610     some datatype definitions may have to be annotated with explicit
  5611     sort constraints.
  5612   - Primrec definitions no longer require function name and type
  5613     of recursive argument.
  5614 
  5615 Consider using isatool fixdatatype to adapt your theories and proof
  5616 scripts to the new package (backup your sources first!).
  5617 
  5618 
  5619 * HOL/record package: considerably improved implementation; now
  5620 includes concrete syntax for record types, terms, updates; theorems
  5621 for surjective pairing and splitting !!-bound record variables; proof
  5622 support is as follows:
  5623 
  5624   1) standard conversions (selectors or updates applied to record
  5625 constructor terms) are part of the standard simpset;
  5626 
  5627   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5628 made part of standard simpset and claset via addIffs;
  5629 
  5630   3) a tactic for record field splitting (record_split_tac) is part of
  5631 the standard claset (addSWrapper);
  5632 
  5633 To get a better idea about these rules you may retrieve them via
  5634 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5635 the name of your record type.
  5636 
  5637 The split tactic 3) conceptually simplifies by the following rule:
  5638 
  5639   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5640 
  5641 Thus any record variable that is bound by meta-all will automatically
  5642 blow up into some record constructor term, consequently the
  5643 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5644 solve record problems automatically.
  5645 
  5646 
  5647 * reorganized the main HOL image: HOL/Integ and String loaded by
  5648 default; theory Main includes everything;
  5649 
  5650 * automatic simplification of integer sums and comparisons, using cancellation;
  5651 
  5652 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5653 
  5654 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5655 
  5656 * many new identities for unions, intersections, set difference, etc.;
  5657 
  5658 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5659 called split_if, split_split, split_sum_case and split_nat_case (to go
  5660 with add/delsplits);
  5661 
  5662 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5663 (?x::unit) = (); this is made part of the default simpset, which COULD
  5664 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5665 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5666 unit_abs_eta_conv is added in order to counter the effect of
  5667 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5668 %u.f();
  5669 
  5670 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5671 makes more sense);
  5672 
  5673 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5674   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5675   disjointness reasoning but breaking a few old proofs.
  5676 
  5677 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5678 to 'converse' from 'inverse' (for compatibility with ZF and some
  5679 literature);
  5680 
  5681 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5682 the well-founded relation;
  5683 
  5684 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5685     Compl A.  The "Compl" syntax remains available as input syntax for this
  5686     release ONLY.
  5687 
  5688 * HOL/Update: new theory of function updates:
  5689     f(a:=b) == %x. if x=a then b else f x
  5690 may also be iterated as in f(a:=b,c:=d,...);
  5691 
  5692 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5693 
  5694 * HOL/List:
  5695   - new function list_update written xs[i:=v] that updates the i-th
  5696     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5697   - new function `upt' written [i..j(] which generates the list
  5698     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5699     bound write [i..j], which is a shorthand for [i..j+1(].
  5700   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5701 
  5702 * HOL/Arith:
  5703   - removed 'pred' (predecessor) function;
  5704   - generalized some theorems about n-1;
  5705   - many new laws about "div" and "mod";
  5706   - new laws about greatest common divisors (see theory ex/Primes);
  5707 
  5708 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5709 instead of "inverse";
  5710 
  5711 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5712   of the multiset ordering;
  5713 
  5714 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5715   (not included by default);
  5716 
  5717 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5718 
  5719 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5720   programs, i.e. different program variables may have different types.
  5721 
  5722 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5723   [previously, this check worked only if the rewrite rule was unconditional]
  5724   Now rew can involve either definitions or equalities (either == or =).
  5725 
  5726 
  5727 *** ZF ***
  5728 
  5729 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5730   only the theorems proved on ZF.ML;
  5731 
  5732 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5733   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5734   disjointness reasoning but breaking a few old proofs.
  5735 
  5736 * ZF/Update: new theory of function updates
  5737     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5738   may also be iterated as in f(a:=b,c:=d,...);
  5739 
  5740 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5741 
  5742 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5743   [previously, this check worked only if the rewrite rule was unconditional]
  5744   Now rew can involve either definitions or equalities (either == or =).
  5745 
  5746 * case_tac provided for compatibility with HOL
  5747     (like the old excluded_middle_tac, but with subgoals swapped)
  5748 
  5749 
  5750 *** Internal programming interfaces ***
  5751 
  5752 * Pure: several new basic modules made available for general use, see
  5753 also src/Pure/README;
  5754 
  5755 * improved the theory data mechanism to support encapsulation (data
  5756 kind name replaced by private Object.kind, acting as authorization
  5757 key); new type-safe user interface via functor TheoryDataFun; generic
  5758 print_data function becomes basically useless;
  5759 
  5760 * removed global_names compatibility flag -- all theory declarations
  5761 are qualified by default;
  5762 
  5763 * module Pure/Syntax now offers quote / antiquote translation
  5764 functions (useful for Hoare logic etc. with implicit dependencies);
  5765 see HOL/ex/Antiquote for an example use;
  5766 
  5767 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5768 cterm -> thm;
  5769 
  5770 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5771 subgoal;
  5772 
  5773 * Display.print_goals function moved to Locale.print_goals;
  5774 
  5775 * standard print function for goals supports current_goals_markers
  5776 variable for marking begin of proof, end of proof, start of goal; the
  5777 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5778 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5779 for example;
  5780 
  5781 
  5782 
  5783 New in Isabelle98 (January 1998)
  5784 --------------------------------
  5785 
  5786 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5787 
  5788 * changed lexical syntax of terms / types: dots made part of long
  5789 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5790 
  5791 * simpset (and claset) reference variable replaced by functions
  5792 simpset / simpset_ref;
  5793 
  5794 * no longer supports theory aliases (via merge) and non-trivial
  5795 implicit merge of thms' signatures;
  5796 
  5797 * most internal names of constants changed due to qualified names;
  5798 
  5799 * changed Pure/Sequence interface (see Pure/seq.ML);
  5800 
  5801 
  5802 *** General Changes ***
  5803 
  5804 * hierachically structured name spaces (for consts, types, axms, thms
  5805 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5806 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5807 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5808 long_names for fully qualified output names; NOTE: ML programs
  5809 (special tactics, packages etc.) referring to internal names may have
  5810 to be adapted to cope with fully qualified names; in case of severe
  5811 backward campatibility problems try setting 'global_names' at compile
  5812 time to have enrything declared within a flat name space; one may also
  5813 fine tune name declarations in theories via the 'global' and 'local'
  5814 section;
  5815 
  5816 * reimplemented the implicit simpset and claset using the new anytype
  5817 data filed in signatures; references simpset:simpset ref etc. are
  5818 replaced by functions simpset:unit->simpset and
  5819 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5820 to patch your ML files accordingly;
  5821 
  5822 * HTML output now includes theory graph data for display with Java
  5823 applet or isatool browser; data generated automatically via isatool
  5824 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5825 
  5826 * defs may now be conditional; improved rewrite_goals_tac to handle
  5827 conditional equations;
  5828 
  5829 * defs now admits additional type arguments, using TYPE('a) syntax;
  5830 
  5831 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5832 creates a new theory node; implicit merge of thms' signatures is
  5833 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5834 transfer:theory->thm->thm in (rare) cases;
  5835 
  5836 * improved handling of draft signatures / theories; draft thms (and
  5837 ctyps, cterms) are automatically promoted to real ones;
  5838 
  5839 * slightly changed interfaces for oracles: admit many per theory, named
  5840 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5841 
  5842 * print_goals: optional output of const types (set show_consts and
  5843 show_types);
  5844 
  5845 * improved output of warnings (###) and errors (***);
  5846 
  5847 * subgoal_tac displays a warning if the new subgoal has type variables;
  5848 
  5849 * removed old README and Makefiles;
  5850 
  5851 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5852 
  5853 * removed obsolete init_pps and init_database;
  5854 
  5855 * deleted the obsolete tactical STATE, which was declared by
  5856     fun STATE tacfun st = tacfun st st;
  5857 
  5858 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5859 (which abbreviates $HOME);
  5860 
  5861 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5862 use isatool fixseq to adapt your ML programs (this works for fully
  5863 qualified references to the Sequence structure only!);
  5864 
  5865 * use_thy no longer requires writable current directory; it always
  5866 reloads .ML *and* .thy file, if either one is out of date;
  5867 
  5868 
  5869 *** Classical Reasoner ***
  5870 
  5871 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5872 tactics that use classical reasoning to simplify a subgoal without
  5873 splitting it into several subgoals;
  5874 
  5875 * Safe_tac: like safe_tac but uses the default claset;
  5876 
  5877 
  5878 *** Simplifier ***
  5879 
  5880 * added simplification meta rules:
  5881     (asm_)(full_)simplify: simpset -> thm -> thm;
  5882 
  5883 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5884 logics (again);
  5885 
  5886 * added prems argument to simplification procedures;
  5887 
  5888 * HOL, FOL, ZF: added infix function `addsplits':
  5889   instead of `<simpset> setloop (split_tac <thms>)'
  5890   you can simply write `<simpset> addsplits <thms>'
  5891 
  5892 
  5893 *** Syntax ***
  5894 
  5895 * TYPE('a) syntax for type reflection terms;
  5896 
  5897 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5898 
  5899 * pretty printer: changed order of mixfix annotation preference (again!);
  5900 
  5901 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5902 
  5903 
  5904 *** HOL ***
  5905 
  5906 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5907   with `addloop' of the simplifier to faciliate case splitting in premises.
  5908 
  5909 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5910 
  5911 * HOL/Auth: new protocol proofs including some for the Internet
  5912   protocol TLS;
  5913 
  5914 * HOL/Map: new theory of `maps' a la VDM;
  5915 
  5916 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5917 cancelling out common nat summands from =, <, <= (in)equalities, or
  5918 differences; simplification procedures nat_cancel_factor for
  5919 cancelling common factor from =, <, <= (in)equalities over natural
  5920 sums; nat_cancel contains both kinds of procedures, it is installed by
  5921 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5922 
  5923 * HOL/simplifier: terms of the form
  5924   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5925   are rewritten to
  5926   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5927   and those of the form
  5928   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5929   are rewritten to
  5930   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5931 
  5932 * HOL/datatype
  5933   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5934 
  5935   P(t_case f1 ... fn x) =
  5936      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5937         ...
  5938        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5939      )
  5940 
  5941   and a theorem `split_t_case_asm' of the form
  5942 
  5943   P(t_case f1 ... fn x) =
  5944     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5945         ...
  5946        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5947      )
  5948   which can be added to a simpset via `addsplits'. The existing theorems
  5949   expand_list_case and expand_option_case have been renamed to
  5950   split_list_case and split_option_case.
  5951 
  5952 * HOL/Arithmetic:
  5953   - `pred n' is automatically converted to `n-1'.
  5954     Users are strongly encouraged not to use `pred' any longer,
  5955     because it will disappear altogether at some point.
  5956   - Users are strongly encouraged to write "0 < n" rather than
  5957     "n ~= 0". Theorems and proof tools have been modified towards this
  5958     `standard'.
  5959 
  5960 * HOL/Lists:
  5961   the function "set_of_list" has been renamed "set" (and its theorems too);
  5962   the function "nth" now takes its arguments in the reverse order and
  5963   has acquired the infix notation "!" as in "xs!n".
  5964 
  5965 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5966 
  5967 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5968   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5969 
  5970 * HOL/record: extensible records with schematic structural subtyping
  5971 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5972 still lacks various theorems and concrete record syntax;
  5973 
  5974 
  5975 *** HOLCF ***
  5976 
  5977 * removed "axioms" and "generated by" sections;
  5978 
  5979 * replaced "ops" section by extended "consts" section, which is capable of
  5980   handling the continuous function space "->" directly;
  5981 
  5982 * domain package:
  5983   . proves theorems immediately and stores them in the theory,
  5984   . creates hierachical name space,
  5985   . now uses normal mixfix annotations (instead of cinfix...),
  5986   . minor changes to some names and values (for consistency),
  5987   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5988   . separator between mutual domain defs: changed "," to "and",
  5989   . improved handling of sort constraints;  now they have to
  5990     appear on the left-hand side of the equations only;
  5991 
  5992 * fixed LAM <x,y,zs>.b syntax;
  5993 
  5994 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5995 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5996 
  5997 
  5998 *** FOL and ZF ***
  5999 
  6000 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6001   with `addloop' of the simplifier to faciliate case splitting in premises.
  6002 
  6003 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6004 in HOL, they strip ALL and --> from proved theorems;
  6005 
  6006 
  6007 
  6008 New in Isabelle94-8 (May 1997)
  6009 ------------------------------
  6010 
  6011 *** General Changes ***
  6012 
  6013 * new utilities to build / run / maintain Isabelle etc. (in parts
  6014 still somewhat experimental); old Makefiles etc. still functional;
  6015 
  6016 * new 'Isabelle System Manual';
  6017 
  6018 * INSTALL text, together with ./configure and ./build scripts;
  6019 
  6020 * reimplemented type inference for greater efficiency, better error
  6021 messages and clean internal interface;
  6022 
  6023 * prlim command for dealing with lots of subgoals (an easier way of
  6024 setting goals_limit);
  6025 
  6026 
  6027 *** Syntax ***
  6028 
  6029 * supports alternative (named) syntax tables (parser and pretty
  6030 printer); internal interface is provided by add_modesyntax(_i);
  6031 
  6032 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6033 be used in conjunction with the Isabelle symbol font; uses the
  6034 "symbols" syntax table;
  6035 
  6036 * added token_translation interface (may translate name tokens in
  6037 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6038 the current print_mode); IMPORTANT: user print translation functions
  6039 are responsible for marking newly introduced bounds
  6040 (Syntax.mark_boundT);
  6041 
  6042 * token translations for modes "xterm" and "xterm_color" that display
  6043 names in bold, underline etc. or colors (which requires a color
  6044 version of xterm);
  6045 
  6046 * infixes may now be declared with names independent of their syntax;
  6047 
  6048 * added typed_print_translation (like print_translation, but may
  6049 access type of constant);
  6050 
  6051 
  6052 *** Classical Reasoner ***
  6053 
  6054 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6055 some limitations.  Blast_tac...
  6056   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6057   + ignores elimination rules that don't have the correct format
  6058         (the conclusion MUST be a formula variable)
  6059   + ignores types, which can make HOL proofs fail
  6060   + rules must not require higher-order unification, e.g. apply_type in ZF
  6061     [message "Function Var's argument not a bound variable" relates to this]
  6062   + its proof strategy is more general but can actually be slower
  6063 
  6064 * substitution with equality assumptions no longer permutes other
  6065 assumptions;
  6066 
  6067 * minor changes in semantics of addafter (now called addaltern); renamed
  6068 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6069 (and access functions for it);
  6070 
  6071 * improved combination of classical reasoner and simplifier:
  6072   + functions for handling clasimpsets
  6073   + improvement of addss: now the simplifier is called _after_ the
  6074     safe steps.
  6075   + safe variant of addss called addSss: uses safe simplifications
  6076     _during_ the safe steps. It is more complete as it allows multiple
  6077     instantiations of unknowns (e.g. with slow_tac).
  6078 
  6079 *** Simplifier ***
  6080 
  6081 * added interface for simplification procedures (functions that
  6082 produce *proven* rewrite rules on the fly, depending on current
  6083 redex);
  6084 
  6085 * ordering on terms as parameter (used for ordered rewriting);
  6086 
  6087 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6088 
  6089 * the solver is now split into a safe and an unsafe part.
  6090 This should be invisible for the normal user, except that the
  6091 functions setsolver and addsolver have been renamed to setSolver and
  6092 addSolver; added safe_asm_full_simp_tac;
  6093 
  6094 
  6095 *** HOL ***
  6096 
  6097 * a generic induction tactic `induct_tac' which works for all datatypes and
  6098 also for type `nat';
  6099 
  6100 * a generic case distinction tactic `exhaust_tac' which works for all
  6101 datatypes and also for type `nat';
  6102 
  6103 * each datatype comes with a function `size';
  6104 
  6105 * patterns in case expressions allow tuple patterns as arguments to
  6106 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6107 
  6108 * primrec now also works with type nat;
  6109 
  6110 * recdef: a new declaration form, allows general recursive functions to be
  6111 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6112 
  6113 * the constant for negation has been renamed from "not" to "Not" to
  6114 harmonize with FOL, ZF, LK, etc.;
  6115 
  6116 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6117 infinite lists;
  6118 
  6119 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6120 
  6121 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6122 problems in commutative rings, using axiomatic type classes for + and *;
  6123 
  6124 * more examples in HOL/MiniML and HOL/Auth;
  6125 
  6126 * more default rewrite rules for quantifiers, union/intersection;
  6127 
  6128 * a new constant `arbitrary == @x.False';
  6129 
  6130 * HOLCF/IOA replaces old HOL/IOA;
  6131 
  6132 * HOLCF changes: derived all rules and arities
  6133   + axiomatic type classes instead of classes
  6134   + typedef instead of faking type definitions
  6135   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6136   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6137   + eliminated the types void, one, tr
  6138   + use unit lift and bool lift (with translations) instead of one and tr
  6139   + eliminated blift from Lift3.thy (use Def instead of blift)
  6140   all eliminated rules are derived as theorems --> no visible changes ;
  6141 
  6142 
  6143 *** ZF ***
  6144 
  6145 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6146 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6147 as ZF_cs addSIs [equalityI];
  6148 
  6149 
  6150 
  6151 New in Isabelle94-7 (November 96)
  6152 ---------------------------------
  6153 
  6154 * allowing negative levels (as offsets) in prlev and choplev;
  6155 
  6156 * super-linear speedup for large simplifications;
  6157 
  6158 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6159 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6160 FAIL); can suppress it using the command Delsimps (ex_simps @
  6161 all_simps); De Morgan laws are also now included, by default;
  6162 
  6163 * improved printing of ==>  :  ~:
  6164 
  6165 * new object-logic "Sequents" adds linear logic, while replacing LK
  6166 and Modal (thanks to Sara Kalvala);
  6167 
  6168 * HOL/Auth: correctness proofs for authentication protocols;
  6169 
  6170 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6171 examples on HOL/Auth);
  6172 
  6173 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6174 the rewriter and classical reasoner simultaneously;
  6175 
  6176 * function uresult no longer returns theorems in "standard" format;
  6177 regain previous version by: val uresult = standard o uresult;
  6178 
  6179 
  6180 
  6181 New in Isabelle94-6
  6182 -------------------
  6183 
  6184 * oracles -- these establish an interface between Isabelle and trusted
  6185 external reasoners, which may deliver results as theorems;
  6186 
  6187 * proof objects (in particular record all uses of oracles);
  6188 
  6189 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6190 
  6191 * "constdefs" section in theory files;
  6192 
  6193 * "primrec" section (HOL) no longer requires names;
  6194 
  6195 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6196 
  6197 
  6198 
  6199 New in Isabelle94-5
  6200 -------------------
  6201 
  6202 * reduced space requirements;
  6203 
  6204 * automatic HTML generation from theories;
  6205 
  6206 * theory files no longer require "..." (quotes) around most types;
  6207 
  6208 * new examples, including two proofs of the Church-Rosser theorem;
  6209 
  6210 * non-curried (1994) version of HOL is no longer distributed;
  6211 
  6212 
  6213 
  6214 New in Isabelle94-4
  6215 -------------------
  6216 
  6217 * greatly reduced space requirements;
  6218 
  6219 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6220 
  6221 * searchable theorem database (see the section "Retrieving theorems" on
  6222 page 8 of the Reference Manual);
  6223 
  6224 * new examples, including Grabczewski's monumental case study of the
  6225 Axiom of Choice;
  6226 
  6227 * The previous version of HOL renamed to Old_HOL;
  6228 
  6229 * The new version of HOL (previously called CHOL) uses a curried syntax
  6230 for functions.  Application looks like f a b instead of f(a,b);
  6231 
  6232 * Mutually recursive inductive definitions finally work in HOL;
  6233 
  6234 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6235 translates to the operator "split";
  6236 
  6237 
  6238 
  6239 New in Isabelle94-3
  6240 -------------------
  6241 
  6242 * new infix operator, addss, allowing the classical reasoner to
  6243 perform simplification at each step of its search.  Example:
  6244         fast_tac (cs addss ss)
  6245 
  6246 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6247 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6248 look like (a,b) instead of <a,b>;
  6249 
  6250 * PLEASE NOTE: CHOL will eventually replace HOL!
  6251 
  6252 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6253 It translates to the operator "split".  A new theory of integers is available;
  6254 
  6255 * In ZF, integer numerals now denote two's-complement binary integers.
  6256 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6257 
  6258 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6259 of the Axiom of Choice;
  6260