NEWS
author haftmann
Thu Jun 25 14:59:29 2009 +0200 (2009-06-25)
changeset 31804 627d142fce19
parent 31790 05c92381363c
child 31810 a6b800855cdd
permissions -rw-r--r--
arbitrary farewell
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Discontinued old form of "escaped symbols" such as \\<forall>.  Only
    10 one backslash should be used, even in ML sources.
    11 
    12 
    13 *** Pure ***
    14 
    15 * On instantiation of classes, remaining undefined class parameters
    16 are formally declared.  INCOMPATIBILITY.
    17 
    18 
    19 *** HOL ***
    20 
    21 * Class semiring_div requires superclass no_zero_divisors and proof of
    22 div_mult_mult1; theorems div_mult_mult1, div_mult_mult2,
    23 div_mult_mult1_if, div_mult_mult1 and div_mult_mult2 have been
    24 generalized to class semiring_div, subsuming former theorems
    25 zdiv_zmult_zmult1, zdiv_zmult_zmult1_if, zdiv_zmult_zmult1 and
    26 zdiv_zmult_zmult2.  div_mult_mult1 is now [simp] by default.
    27 INCOMPATIBILITY.
    28 
    29 * Power operations on relations and functions are now one dedicate
    30 constant compow with infix syntax "^^".  Power operations on
    31 multiplicative monoids retains syntax "^" and is now defined generic
    32 in class power.  INCOMPATIBILITY.
    33 
    34 * ML antiquotation @{code_datatype} inserts definition of a datatype
    35 generated by the code generator; see Predicate.thy for an example.
    36 
    37 * New method "linarith" invokes existing linear arithmetic decision
    38 procedure only.
    39 
    40 * Implementation of quickcheck using generic code generator; default generators
    41 are provided for all suitable HOL types, records and datatypes.
    42 
    43 * Constants Set.Pow and Set.image now with authentic syntax; object-logic definitions
    44 Set.Pow_def and Set.image_def.  INCOMPATIBILITY.
    45 
    46 * Renamed theorems:
    47 Suc_eq_add_numeral_1 -> Suc_eq_plus1
    48 Suc_eq_add_numeral_1_left -> Suc_eq_plus1_left
    49 Suc_plus1 -> Suc_eq_plus1
    50 
    51 * Discontinued ancient tradition to suffix certain ML module names with "_package", e.g.:
    52 
    53     DatatypePackage ~> Datatype
    54     InductivePackage ~> Inductive
    55 
    56     etc.
    57 
    58 INCOMPATIBILITY.
    59 
    60 * NewNumberTheory: Jeremy Avigad's new version of part of NumberTheory.
    61 If possible, use NewNumberTheory, not NumberTheory.
    62 
    63 * Simplified interfaces of datatype module.  INCOMPATIBILITY.
    64 
    65 * Abbreviation "arbitrary" of "undefined" has disappeared; use "undefined" directly.
    66 INCOMPATIBILITY.
    67 
    68 
    69 *** ML ***
    70 
    71 * Eliminated old Attrib.add_attributes, Method.add_methods and related
    72 cominators for "args".  INCOMPATIBILITY, need to use simplified
    73 Attrib/Method.setup introduced in Isabelle2009.
    74 
    75 
    76 *** System ***
    77 
    78 * Discontinued support for Poly/ML 4.x versions.
    79 
    80 * Removed "compress" option from isabelle-process and isabelle usedir;
    81 this is always enabled.
    82 
    83 
    84 
    85 New in Isabelle2009 (April 2009)
    86 --------------------------------
    87 
    88 *** General ***
    89 
    90 * Simplified main Isabelle executables, with less surprises on
    91 case-insensitive file-systems (such as Mac OS).
    92 
    93   - The main Isabelle tool wrapper is now called "isabelle" instead of
    94     "isatool."
    95 
    96   - The former "isabelle" alias for "isabelle-process" has been
    97     removed (should rarely occur to regular users).
    98 
    99   - The former "isabelle-interface" and its alias "Isabelle" have been
   100     removed (interfaces are now regular Isabelle tools).
   101 
   102 Within scripts and make files, the Isabelle environment variables
   103 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
   104 respectively.  (The latter are still available as legacy feature.)
   105 
   106 The old isabelle-interface wrapper could react in confusing ways if
   107 the interface was uninstalled or changed otherwise.  Individual
   108 interface tool configuration is now more explicit, see also the
   109 Isabelle system manual.  In particular, Proof General is now available
   110 via "isabelle emacs".
   111 
   112 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
   113 purge installed copies of Isabelle executables and re-run "isabelle
   114 install -p ...", or use symlinks.
   115 
   116 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
   117 old ~/isabelle, which was slightly non-standard and apt to cause
   118 surprises on case-insensitive file-systems (such as Mac OS).
   119 
   120 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
   121 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
   122 care is required when using older releases of Isabelle.  Note that
   123 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
   124 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
   125 
   126 * Proofs of fully specified statements are run in parallel on
   127 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
   128 a regular 4-core machine, if the initial heap space is made reasonably
   129 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
   130 
   131 * The main reference manuals ("isar-ref", "implementation", and
   132 "system") have been updated and extended.  Formally checked references
   133 as hyperlinks are now available uniformly.
   134 
   135 
   136 *** Pure ***
   137 
   138 * Complete re-implementation of locales.  INCOMPATIBILITY in several
   139 respects.  The most important changes are listed below.  See the
   140 Tutorial on Locales ("locales" manual) for details.
   141 
   142 - In locale expressions, instantiation replaces renaming.  Parameters
   143 must be declared in a for clause.  To aid compatibility with previous
   144 parameter inheritance, in locale declarations, parameters that are not
   145 'touched' (instantiation position "_" or omitted) are implicitly added
   146 with their syntax at the beginning of the for clause.
   147 
   148 - Syntax from abbreviations and definitions in locales is available in
   149 locale expressions and context elements.  The latter is particularly
   150 useful in locale declarations.
   151 
   152 - More flexible mechanisms to qualify names generated by locale
   153 expressions.  Qualifiers (prefixes) may be specified in locale
   154 expressions, and can be marked as mandatory (syntax: "name!:") or
   155 optional (syntax "name?:").  The default depends for plain "name:"
   156 depends on the situation where a locale expression is used: in
   157 commands 'locale' and 'sublocale' prefixes are optional, in
   158 'interpretation' and 'interpret' prefixes are mandatory.  The old
   159 implicit qualifiers derived from the parameter names of a locale are
   160 no longer generated.
   161 
   162 - Command "sublocale l < e" replaces "interpretation l < e".  The
   163 instantiation clause in "interpretation" and "interpret" (square
   164 brackets) is no longer available.  Use locale expressions.
   165 
   166 - When converting proof scripts, mandatory qualifiers in
   167 'interpretation' and 'interpret' should be retained by default, even
   168 if this is an INCOMPATIBILITY compared to former behavior.  In the
   169 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   170 in locale expressions range over a single locale instance only.
   171 
   172 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   173 In existing theorem specifications replace the includes element by the
   174 respective context elements of the included locale, omitting those
   175 that are already present in the theorem specification.  Multiple
   176 assume elements of a locale should be replaced by a single one
   177 involving the locale predicate.  In the proof body, declarations (most
   178 notably theorems) may be regained by interpreting the respective
   179 locales in the proof context as required (command "interpret").
   180 
   181 If using "includes" in replacement of a target solely because the
   182 parameter types in the theorem are not as general as in the target,
   183 consider declaring a new locale with additional type constraints on
   184 the parameters (context element "constrains").
   185 
   186 - Discontinued "locale (open)".  INCOMPATIBILITY.
   187 
   188 - Locale interpretation commands no longer attempt to simplify goal.
   189 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   190 methods intro_locales and unfold_locales to clarify.
   191 
   192 - Locale interpretation commands no longer accept interpretation
   193 attributes.  INCOMPATIBILITY.
   194 
   195 * Class declaration: so-called "base sort" must not be given in import
   196 list any longer, but is inferred from the specification.  Particularly
   197 in HOL, write
   198 
   199     class foo = ...
   200 
   201 instead of
   202 
   203     class foo = type + ...
   204 
   205 * Class target: global versions of theorems stemming do not carry a
   206 parameter prefix any longer.  INCOMPATIBILITY.
   207 
   208 * Class 'instance' command no longer accepts attached definitions.
   209 INCOMPATIBILITY, use proper 'instantiation' target instead.
   210 
   211 * Recovered hiding of consts, which was accidentally broken in
   212 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   213 makes c inaccessible; consider using ``hide (open) const c'' instead.
   214 
   215 * Slightly more coherent Pure syntax, with updated documentation in
   216 isar-ref manual.  Removed locales meta_term_syntax and
   217 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   218 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   219 directly in regular applications.
   220 
   221 * There is a new syntactic category "float_const" for signed decimal
   222 fractions (e.g. 123.45 or -123.45).
   223 
   224 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   225 interface with 'setup' command instead.
   226 
   227 * Command 'local_setup' is similar to 'setup', but operates on a local
   228 theory context.
   229 
   230 * The 'axiomatization' command now only works within a global theory
   231 context.  INCOMPATIBILITY.
   232 
   233 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   234 hypotheses.  Sorts required in the course of reasoning need to be
   235 covered by the constraints in the initial statement, completed by the
   236 type instance information of the background theory.  Non-trivial sort
   237 hypotheses, which rarely occur in practice, may be specified via
   238 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   239 
   240   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   241 
   242 The result contains an implicit sort hypotheses as before --
   243 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   244 normalization.
   245 
   246 * Generalized Isar history, with support for linear undo, direct state
   247 addressing etc.
   248 
   249 * Changed defaults for unify configuration options:
   250 
   251   unify_trace_bound = 50 (formerly 25)
   252   unify_search_bound = 60 (formerly 30)
   253 
   254 * Different bookkeeping for code equations (INCOMPATIBILITY):
   255 
   256   a) On theory merge, the last set of code equations for a particular
   257      constant is taken (in accordance with the policy applied by other
   258      parts of the code generator framework).
   259 
   260   b) Code equations stemming from explicit declarations (e.g. code
   261      attribute) gain priority over default code equations stemming
   262      from definition, primrec, fun etc.
   263 
   264 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   265 
   266 * Unified theorem tables for both code generators.  Thus [code
   267 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   268 
   269 * Command 'find_consts' searches for constants based on type and name
   270 patterns, e.g.
   271 
   272     find_consts "_ => bool"
   273 
   274 By default, matching is against subtypes, but it may be restricted to
   275 the whole type.  Searching by name is possible.  Multiple queries are
   276 conjunctive and queries may be negated by prefixing them with a
   277 hyphen:
   278 
   279     find_consts strict: "_ => bool" name: "Int" -"int => int"
   280 
   281 * New 'find_theorems' criterion "solves" matches theorems that
   282 directly solve the current goal (modulo higher-order unification).
   283 
   284 * Auto solve feature for main theorem statements: whenever a new goal
   285 is stated, "find_theorems solves" is called; any theorems that could
   286 solve the lemma directly are listed as part of the goal state.
   287 Cf. associated options in Proof General Isabelle settings menu,
   288 enabled by default, with reasonable timeout for pathological cases of
   289 higher-order unification.
   290 
   291 
   292 *** Document preparation ***
   293 
   294 * Antiquotation @{lemma} now imitates a regular terminal proof,
   295 demanding keyword 'by' and supporting the full method expression
   296 syntax just like the Isar command 'by'.
   297 
   298 
   299 *** HOL ***
   300 
   301 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   302 points Main and Complex_Main remain as before.
   303 
   304 * Logic image HOL-Plain provides a minimal HOL with the most important
   305 tools available (inductive, datatype, primrec, ...).  This facilitates
   306 experimentation and tool development.  Note that user applications
   307 (and library theories) should never refer to anything below theory
   308 Main, as before.
   309 
   310 * Logic image HOL-Main stops at theory Main, and thus facilitates
   311 experimentation due to shorter build times.
   312 
   313 * Logic image HOL-NSA contains theories of nonstandard analysis which
   314 were previously part of former HOL-Complex.  Entry point Hyperreal
   315 remains valid, but theories formerly using Complex_Main should now use
   316 new entry point Hypercomplex.
   317 
   318 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   319 Posix processes.  Avoids potentially expensive forking of the ML
   320 process.  New thread-based implementation also works on non-Unix
   321 platforms (Cygwin).  Provers are no longer hardwired, but defined
   322 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   323 commands are covered in the isar-ref manual.
   324 
   325 * Wrapper scripts for remote SystemOnTPTP service allows to use
   326 sledgehammer without local ATP installation (Vampire etc.). Other
   327 provers may be included via suitable ML wrappers, see also
   328 src/HOL/ATP_Linkup.thy.
   329 
   330 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   331 menu.
   332 
   333 * The metis method no longer fails because the theorem is too trivial
   334 (contains the empty clause).
   335 
   336 * The metis method now fails in the usual manner, rather than raising
   337 an exception, if it determines that it cannot prove the theorem.
   338 
   339 * Method "coherent" implements a prover for coherent logic (see also
   340 src/Tools/coherent.ML).
   341 
   342 * Constants "undefined" and "default" replace "arbitrary".  Usually
   343 "undefined" is the right choice to replace "arbitrary", though
   344 logically there is no difference.  INCOMPATIBILITY.
   345 
   346 * Command "value" now integrates different evaluation mechanisms.  The
   347 result of the first successful evaluation mechanism is printed.  In
   348 square brackets a particular named evaluation mechanisms may be
   349 specified (currently, [SML], [code] or [nbe]).  See further
   350 src/HOL/ex/Eval_Examples.thy.
   351 
   352 * Normalization by evaluation now allows non-leftlinear equations.
   353 Declare with attribute [code nbe].
   354 
   355 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   356 as the structured Isar versions "cases" and "induct", cf. the
   357 corresponding "cases" and "induct" attributes.  Mutual induction rules
   358 are now presented as a list of individual projections
   359 (e.g. foo_bar.inducts for types foo and bar); the old format with
   360 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   361 rare situations a different rule is selected --- notably nested tuple
   362 elimination instead of former prod.exhaust: use explicit (case_tac t
   363 rule: prod.exhaust) here.
   364 
   365 * Attributes "cases", "induct", "coinduct" support "del" option.
   366 
   367 * Removed fact "case_split_thm", which duplicates "case_split".
   368 
   369 * The option datatype has been moved to a new theory Option.  Renamed
   370 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   371 
   372 * New predicate "strict_mono" classifies strict functions on partial
   373 orders.  With strict functions on linear orders, reasoning about
   374 (in)equalities is facilitated by theorems "strict_mono_eq",
   375 "strict_mono_less_eq" and "strict_mono_less".
   376 
   377 * Some set operations are now proper qualified constants with
   378 authentic syntax.  INCOMPATIBILITY:
   379 
   380     op Int ~>   Set.Int
   381     op Un ~>    Set.Un
   382     INTER ~>    Set.INTER
   383     UNION ~>    Set.UNION
   384     Inter ~>    Set.Inter
   385     Union ~>    Set.Union
   386     {} ~>       Set.empty
   387     UNIV ~>     Set.UNIV
   388 
   389 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   390 theory Set.
   391 
   392 * Auxiliary class "itself" has disappeared -- classes without any
   393 parameter are treated as expected by the 'class' command.
   394 
   395 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   396 
   397 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   398 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   399 
   400 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   401 method "approximation".  It proves formulas on real values by using
   402 interval arithmetic.  In the formulas are also the transcendental
   403 functions sin, cos, tan, atan, ln, exp and the constant pi are
   404 allowed. For examples see
   405 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   406 
   407 * Theory "Reflection" now resides in HOL/Library.
   408 
   409 * Entry point to Word library now simply named "Word".
   410 INCOMPATIBILITY.
   411 
   412 * Made source layout more coherent with logical distribution
   413 structure:
   414 
   415     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   416     src/HOL/Library/Code_Message.thy ~> src/HOL/
   417     src/HOL/Library/GCD.thy ~> src/HOL/
   418     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   419     src/HOL/Library/Parity.thy ~> src/HOL/
   420     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   421     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   422     src/HOL/Real/Lubs.thy ~> src/HOL/
   423     src/HOL/Real/PReal.thy ~> src/HOL/
   424     src/HOL/Real/Rational.thy ~> src/HOL/
   425     src/HOL/Real/RComplete.thy ~> src/HOL/
   426     src/HOL/Real/RealDef.thy ~> src/HOL/
   427     src/HOL/Real/RealPow.thy ~> src/HOL/
   428     src/HOL/Real/Real.thy ~> src/HOL/
   429     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   430     src/HOL/Complex/Complex.thy ~> src/HOL/
   431     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   432     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   433     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   434     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   435     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   436     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   437     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   438     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   439     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   440     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   441     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   442     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   443     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   444     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   445     src/HOL/Real/Float ~> src/HOL/Library/
   446     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   447     src/HOL/Real/RealVector.thy ~> src/HOL/
   448 
   449     src/HOL/arith_data.ML ~> src/HOL/Tools
   450     src/HOL/hologic.ML ~> src/HOL/Tools
   451     src/HOL/simpdata.ML ~> src/HOL/Tools
   452     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   453     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   454     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   455     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   456     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   457     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   458     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   459 
   460     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   461     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   462     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   463     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   464     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   465     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   466 
   467 * If methods "eval" and "evaluation" encounter a structured proof
   468 state with !!/==>, only the conclusion is evaluated to True (if
   469 possible), avoiding strange error messages.
   470 
   471 * Method "sizechange" automates termination proofs using (a
   472 modification of) the size-change principle.  Requires SAT solver.  See
   473 src/HOL/ex/Termination.thy for examples.
   474 
   475 * Simplifier: simproc for let expressions now unfolds if bound
   476 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   477 
   478 * Method "arith": Linear arithmetic now ignores all inequalities when
   479 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   480 
   481 * New attribute "arith" for facts that should always be used
   482 automatically by arithmetic. It is intended to be used locally in
   483 proofs, e.g.
   484 
   485   assumes [arith]: "x > 0"
   486 
   487 Global usage is discouraged because of possible performance impact.
   488 
   489 * New classes "top" and "bot" with corresponding operations "top" and
   490 "bot" in theory Orderings; instantiation of class "complete_lattice"
   491 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   492 
   493 * Changed definition lemma "less_fun_def" in order to provide an
   494 instance for preorders on functions; use lemma "less_le" instead.
   495 INCOMPATIBILITY.
   496 
   497 * Theory Orderings: class "wellorder" moved here, with explicit
   498 induction rule "less_induct" as assumption.  For instantiation of
   499 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   500 INCOMPATIBILITY.
   501 
   502 * Theory Orderings: added class "preorder" as superclass of "order".
   503 INCOMPATIBILITY: Instantiation proofs for order, linorder
   504 etc. slightly changed.  Some theorems named order_class.* now named
   505 preorder_class.*.
   506 
   507 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   508 "diag" to "Id_on".
   509 
   510 * Theory Finite_Set: added a new fold combinator of type
   511 
   512   ('a => 'b => 'b) => 'b => 'a set => 'b
   513 
   514 Occasionally this is more convenient than the old fold combinator
   515 which is now defined in terms of the new one and renamed to
   516 fold_image.
   517 
   518 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   519 and "ring_simps" have been replaced by "algebra_simps" (which can be
   520 extended with further lemmas!).  At the moment both still exist but
   521 the former will disappear at some point.
   522 
   523 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   524 class recpower.  Type-specific simp rules for various recpower types
   525 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   526 
   527 rat_power_0    -> power_0
   528 rat_power_Suc  -> power_Suc
   529 realpow_0      -> power_0
   530 realpow_Suc    -> power_Suc
   531 complexpow_0   -> power_0
   532 complexpow_Suc -> power_Suc
   533 power_poly_0   -> power_0
   534 power_poly_Suc -> power_Suc
   535 
   536 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   537 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   538 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   539 of lemmas from Divides has been generalized from nat to class
   540 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   541 renames resulting from duplicate elimination:
   542 
   543     dvd_def_mod ~>          dvd_eq_mod_eq_0
   544     zero_dvd_iff ~>         dvd_0_left_iff
   545     dvd_0 ~>                dvd_0_right
   546     DIVISION_BY_ZERO_DIV ~> div_by_0
   547     DIVISION_BY_ZERO_MOD ~> mod_by_0
   548     mult_div ~>             div_mult_self2_is_id
   549     mult_mod ~>             mod_mult_self2_is_0
   550 
   551 * Theory IntDiv: removed many lemmas that are instances of class-based
   552 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   553 rename old lemmas as follows:
   554 
   555 dvd_diff               -> nat_dvd_diff
   556 dvd_zminus_iff         -> dvd_minus_iff
   557 mod_add1_eq            -> mod_add_eq
   558 mod_mult1_eq           -> mod_mult_right_eq
   559 mod_mult1_eq'          -> mod_mult_left_eq
   560 mod_mult_distrib_mod   -> mod_mult_eq
   561 nat_mod_add_left_eq    -> mod_add_left_eq
   562 nat_mod_add_right_eq   -> mod_add_right_eq
   563 nat_mod_div_trivial    -> mod_div_trivial
   564 nat_mod_mod_trivial    -> mod_mod_trivial
   565 zdiv_zadd_self1        -> div_add_self1
   566 zdiv_zadd_self2        -> div_add_self2
   567 zdiv_zmult_self1       -> div_mult_self2_is_id
   568 zdiv_zmult_self2       -> div_mult_self1_is_id
   569 zdvd_triv_left         -> dvd_triv_left
   570 zdvd_triv_right        -> dvd_triv_right
   571 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   572 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   573 zmod_zadd_left_eq      -> mod_add_left_eq
   574 zmod_zadd_right_eq     -> mod_add_right_eq
   575 zmod_zadd_self1        -> mod_add_self1
   576 zmod_zadd_self2        -> mod_add_self2
   577 zmod_zadd1_eq          -> mod_add_eq
   578 zmod_zdiff1_eq         -> mod_diff_eq
   579 zmod_zdvd_zmod         -> mod_mod_cancel
   580 zmod_zmod_cancel       -> mod_mod_cancel
   581 zmod_zmult_self1       -> mod_mult_self2_is_0
   582 zmod_zmult_self2       -> mod_mult_self1_is_0
   583 zmod_1                 -> mod_by_1
   584 zdiv_1                 -> div_by_1
   585 zdvd_abs1              -> abs_dvd_iff
   586 zdvd_abs2              -> dvd_abs_iff
   587 zdvd_refl              -> dvd_refl
   588 zdvd_trans             -> dvd_trans
   589 zdvd_zadd              -> dvd_add
   590 zdvd_zdiff             -> dvd_diff
   591 zdvd_zminus_iff        -> dvd_minus_iff
   592 zdvd_zminus2_iff       -> minus_dvd_iff
   593 zdvd_zmultD            -> dvd_mult_right
   594 zdvd_zmultD2           -> dvd_mult_left
   595 zdvd_zmult_mono        -> mult_dvd_mono
   596 zdvd_0_right           -> dvd_0_right
   597 zdvd_0_left            -> dvd_0_left_iff
   598 zdvd_1_left            -> one_dvd
   599 zminus_dvd_iff         -> minus_dvd_iff
   600 
   601 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   602 
   603 * The real numbers offer decimal input syntax: 12.34 is translated
   604 into 1234/10^2. This translation is not reversed upon output.
   605 
   606 * Theory Library/Polynomial defines an abstract type 'a poly of
   607 univariate polynomials with coefficients of type 'a.  In addition to
   608 the standard ring operations, it also supports div and mod.  Code
   609 generation is also supported, using list-style constructors.
   610 
   611 * Theory Library/Inner_Product defines a class of real_inner for real
   612 inner product spaces, with an overloaded operation inner :: 'a => 'a
   613 => real.  Class real_inner is a subclass of real_normed_vector from
   614 theory RealVector.
   615 
   616 * Theory Library/Product_Vector provides instances for the product
   617 type 'a * 'b of several classes from RealVector and Inner_Product.
   618 Definitions of addition, subtraction, scalar multiplication, norms,
   619 and inner products are included.
   620 
   621 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   622 addition to the field operations, numerals and case syntax are also
   623 supported.
   624 
   625 * Theory Library/Diagonalize provides constructive version of Cantor's
   626 first diagonalization argument.
   627 
   628 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   629 zlcm (for int); carried together from various gcd/lcm developements in
   630 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   631 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   632 may recover tupled syntax as follows:
   633 
   634     hide (open) const gcd
   635     abbreviation gcd where
   636       "gcd == (%(a, b). GCD.gcd a b)"
   637     notation (output)
   638       GCD.gcd ("gcd '(_, _')")
   639 
   640 The same works for lcm, zgcd, zlcm.
   641 
   642 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   643 instantiations for algebraic structures.  Removed some duplicate
   644 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   645 
   646 * ML antiquotation @{code} takes a constant as argument and generates
   647 corresponding code in background and inserts name of the corresponding
   648 resulting ML value/function/datatype constructor binding in place.
   649 All occurrences of @{code} with a single ML block are generated
   650 simultaneously.  Provides a generic and safe interface for
   651 instrumentalizing code generation.  See
   652 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   653 In future you ought to refrain from ad-hoc compiling generated SML
   654 code on the ML toplevel.  Note that (for technical reasons) @{code}
   655 cannot refer to constants for which user-defined serializations are
   656 set.  Refer to the corresponding ML counterpart directly in that
   657 cases.
   658 
   659 * Command 'rep_datatype': instead of theorem names the command now
   660 takes a list of terms denoting the constructors of the type to be
   661 represented as datatype.  The characteristic theorems have to be
   662 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   663 have disappeared in favour of existing ones:
   664 
   665     unit_induct                 ~> unit.induct
   666     prod_induct                 ~> prod.induct
   667     sum_induct                  ~> sum.induct
   668     Suc_Suc_eq                  ~> nat.inject
   669     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   670 
   671 
   672 *** HOL-Algebra ***
   673 
   674 * New locales for orders and lattices where the equivalence relation
   675 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   676 locales use a record structure with field eq for the equivalence.
   677 
   678 * New theory of factorial domains.
   679 
   680 * Units_l_inv and Units_r_inv are now simp rules by default.
   681 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   682 and/or r_inv will now also require deletion of these lemmas.
   683 
   684 * Renamed the following theorems, INCOMPATIBILITY:
   685 
   686 UpperD ~> Upper_memD
   687 LowerD ~> Lower_memD
   688 least_carrier ~> least_closed
   689 greatest_carrier ~> greatest_closed
   690 greatest_Lower_above ~> greatest_Lower_below
   691 one_zero ~> carrier_one_zero
   692 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   693 
   694 
   695 *** HOL-Nominal ***
   696 
   697 * Nominal datatypes can now contain type-variables.
   698 
   699 * Commands 'nominal_inductive' and 'equivariance' work with local
   700 theory targets.
   701 
   702 * Nominal primrec can now works with local theory targets and its
   703 specification syntax now conforms to the general format as seen in
   704 'inductive' etc.
   705 
   706 * Method "perm_simp" honours the standard simplifier attributes
   707 (no_asm), (no_asm_use) etc.
   708 
   709 * The new predicate #* is defined like freshness, except that on the
   710 left hand side can be a set or list of atoms.
   711 
   712 * Experimental command 'nominal_inductive2' derives strong induction
   713 principles for inductive definitions.  In contrast to
   714 'nominal_inductive', which can only deal with a fixed number of
   715 binders, it can deal with arbitrary expressions standing for sets of
   716 atoms to be avoided.  The only inductive definition we have at the
   717 moment that needs this generalisation is the typing rule for Lets in
   718 the algorithm W:
   719 
   720  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   721  -----------------------------------------------------------------
   722          Gamma |- Let x be t1 in t2 : T2
   723 
   724 In this rule one wants to avoid all the binders that are introduced by
   725 "close Gamma T1".  We are looking for other examples where this
   726 feature might be useful.  Please let us know.
   727 
   728 
   729 *** HOLCF ***
   730 
   731 * Reimplemented the simplification procedure for proving continuity
   732 subgoals.  The new simproc is extensible; users can declare additional
   733 continuity introduction rules with the attribute [cont2cont].
   734 
   735 * The continuity simproc now uses a different introduction rule for
   736 solving continuity subgoals on terms with lambda abstractions.  In
   737 some rare cases the new simproc may fail to solve subgoals that the
   738 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   739 Potential INCOMPATIBILITY.
   740 
   741 * Command 'fixrec': specification syntax now conforms to the general
   742 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   743 examples.  INCOMPATIBILITY.
   744 
   745 
   746 *** ZF ***
   747 
   748 * Proof of Zorn's Lemma for partial orders.
   749 
   750 
   751 *** ML ***
   752 
   753 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   754 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   755 depends on multithreading, so timouts will not work before Poly/ML
   756 5.2.1!
   757 
   758 * High-level support for concurrent ML programming, see
   759 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   760 particularly convenient to organize independent functional
   761 computations.  The concept of "synchronized variables" provides a
   762 higher-order interface for components with shared state, avoiding the
   763 delicate details of mutexes and condition variables.  (Requires
   764 Poly/ML 5.2.1 or later.)
   765 
   766 * ML bindings produced via Isar commands are stored within the Isar
   767 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   768 become thread-safe and work with undo as expected (concerning
   769 top-level bindings, not side-effects on global references).
   770 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   771 compiler at runtime; really global bindings need to be given outside a
   772 theory.  (Requires Poly/ML 5.2 or later.)
   773 
   774 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   775 context.  Top-level ML bindings are stored within the proof context in
   776 a purely sequential fashion, disregarding the nested proof structure.
   777 ML bindings introduced by 'ML_prf' are discarded at the end of the
   778 proof.  (Requires Poly/ML 5.2 or later.)
   779 
   780 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   781 and Method.setup, as well as Isar commands 'attribute_setup' and
   782 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   783 existing code accordingly, or use plain 'setup' together with old
   784 Method.add_method.
   785 
   786 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   787 to 'a -> thm, while results are always tagged with an authentic oracle
   788 name.  The Isar command 'oracle' is now polymorphic, no argument type
   789 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   790 accordingly.  Note that extra performance may be gained by producing
   791 the cterm carefully, avoiding slow Thm.cterm_of.
   792 
   793 * Simplified interface for defining document antiquotations via
   794 ThyOutput.antiquotation, ThyOutput.output, and optionally
   795 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   796 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   797 examples.
   798 
   799 * More systematic treatment of long names, abstract name bindings, and
   800 name space operations.  Basic operations on qualified names have been
   801 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   802 Long_Name.append.  Old type bstring has been mostly replaced by
   803 abstract type binding (see structure Binding), which supports precise
   804 qualification by packages and local theory targets, as well as proper
   805 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   806 bstring values into Binding.name, or better pass through abstract
   807 bindings everywhere.  See further src/Pure/General/long_name.ML,
   808 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   809 
   810 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   811 LocalTheory.note etc.) now refer to the *full* internal name, not the
   812 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   813 
   814 * Disposed old type and term read functions (Sign.read_def_typ,
   815 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   816 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   817 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   818 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   819 resort for legacy applications.
   820 
   821 * Disposed old declarations, tactics, tactic combinators that refer to
   822 the simpset or claset of an implicit theory (such as Addsimps,
   823 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   824 embedded ML text, or local_simpset_of with a proper context passed as
   825 explicit runtime argument.
   826 
   827 * Rules and tactics that read instantiations (read_instantiate,
   828 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   829 context, which is required for parsing and type-checking.  Moreover,
   830 the variables are specified as plain indexnames, not string encodings
   831 thereof.  INCOMPATIBILITY.
   832 
   833 * Generic Toplevel.add_hook interface allows to analyze the result of
   834 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   835 for theorem dependency output of transactions resulting in a new
   836 theory state.
   837 
   838 * ML antiquotations: block-structured compilation context indicated by
   839 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   840 
   841   @{binding name}                         - basic name binding
   842   @{let ?pat = term}                      - term abbreviation (HO matching)
   843   @{note name = fact}                     - fact abbreviation
   844   @{thm fact}                             - singleton fact (with attributes)
   845   @{thms fact}                            - general fact (with attributes)
   846   @{lemma prop by method}                 - singleton goal
   847   @{lemma prop by meth1 meth2}            - singleton goal
   848   @{lemma prop1 ... propN by method}      - general goal
   849   @{lemma prop1 ... propN by meth1 meth2} - general goal
   850   @{lemma (open) ...}                     - open derivation
   851 
   852 
   853 *** System ***
   854 
   855 * The Isabelle "emacs" tool provides a specific interface to invoke
   856 Proof General / Emacs, with more explicit failure if that is not
   857 installed (the old isabelle-interface script silently falls back on
   858 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   859 installation location of the Proof General distribution.
   860 
   861 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   862 the Isabelle process into a JVM/Scala application.  See
   863 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   864 process wrapper has been discontinued.)
   865 
   866 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   867 
   868 * Various status messages (with exact source position information) are
   869 emitted, if proper markup print mode is enabled.  This allows
   870 user-interface components to provide detailed feedback on internal
   871 prover operations.
   872 
   873 
   874 
   875 New in Isabelle2008 (June 2008)
   876 -------------------------------
   877 
   878 *** General ***
   879 
   880 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   881 and updated, with formally checked references as hyperlinks.
   882 
   883 * Theory loader: use_thy (and similar operations) no longer set the
   884 implicit ML context, which was occasionally hard to predict and in
   885 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   886 provides a proper context already.
   887 
   888 * Theory loader: old-style ML proof scripts being *attached* to a thy
   889 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   890 'use' within a theory file will do the job.
   891 
   892 * Name space merge now observes canonical order, i.e. the second space
   893 is inserted into the first one, while existing entries in the first
   894 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   895 swap theory imports.
   896 
   897 * Syntax: symbol \<chi> is now considered a letter.  Potential
   898 INCOMPATIBILITY in identifier syntax etc.
   899 
   900 * Outer syntax: string tokens no longer admit escaped white space,
   901 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   902 white space without escapes.
   903 
   904 * Outer syntax: string tokens may contain arbitrary character codes
   905 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   906 "foo_bar".
   907 
   908 
   909 *** Pure ***
   910 
   911 * Context-dependent token translations.  Default setup reverts locally
   912 fixed variables, and adds hilite markup for undeclared frees.
   913 
   914 * Unused theorems can be found using the new command 'unused_thms'.
   915 There are three ways of invoking it:
   916 
   917 (1) unused_thms
   918      Only finds unused theorems in the current theory.
   919 
   920 (2) unused_thms thy_1 ... thy_n -
   921      Finds unused theorems in the current theory and all of its ancestors,
   922      excluding the theories thy_1 ... thy_n and all of their ancestors.
   923 
   924 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   925      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   926      their ancestors, excluding the theories thy_1 ... thy_n and all of
   927      their ancestors.
   928 
   929 In order to increase the readability of the list produced by
   930 unused_thms, theorems that have been created by a particular instance
   931 of a theory command such as 'inductive' or 'function' are considered
   932 to belong to the same "group", meaning that if at least one theorem in
   933 this group is used, the other theorems in the same group are no longer
   934 reported as unused.  Moreover, if all theorems in the group are
   935 unused, only one theorem in the group is displayed.
   936 
   937 Note that proof objects have to be switched on in order for
   938 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   939 usually the case when using Proof General with the default settings).
   940 
   941 * Authentic naming of facts disallows ad-hoc overwriting of previous
   942 theorems within the same name space.  INCOMPATIBILITY, need to remove
   943 duplicate fact bindings, or even accidental fact duplications.  Note
   944 that tools may maintain dynamically scoped facts systematically, using
   945 PureThy.add_thms_dynamic.
   946 
   947 * Command 'hide' now allows to hide from "fact" name space as well.
   948 
   949 * Eliminated destructive theorem database, simpset, claset, and
   950 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   951 update of theories within ML code.
   952 
   953 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   954 INCOMPATIBILITY, object-logics depending on former Pure require
   955 additional setup PureThy.old_appl_syntax_setup; object-logics
   956 depending on former CPure need to refer to Pure.
   957 
   958 * Commands 'use' and 'ML' are now purely functional, operating on
   959 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   960 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   961 INCOMPATIBILITY.
   962 
   963 * Command 'setup': discontinued implicit version with ML reference.
   964 
   965 * Instantiation target allows for simultaneous specification of class
   966 instance operations together with an instantiation proof.
   967 Type-checking phase allows to refer to class operations uniformly.
   968 See src/HOL/Complex/Complex.thy for an Isar example and
   969 src/HOL/Library/Eval.thy for an ML example.
   970 
   971 * Indexing of literal facts: be more serious about including only
   972 facts from the visible specification/proof context, but not the
   973 background context (locale etc.).  Affects `prop` notation and method
   974 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   975 situations.
   976 
   977 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   978 "(open)" option, which used to expose internal bound variables to the
   979 proof text.
   980 
   981 * Isar statements: removed obsolete case "rule_context".
   982 INCOMPATIBILITY, better use explicit fixes/assumes.
   983 
   984 * Locale proofs: default proof step now includes 'unfold_locales';
   985 hence 'proof' without argument may be used to unfold locale
   986 predicates.
   987 
   988 
   989 *** Document preparation ***
   990 
   991 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   992 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   993 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   994 spot); renamed link color from "darkblue" to "linkcolor" (default
   995 value unchanged, can be redefined via \definecolor); no longer sets
   996 "a4paper" option (unnecessary or even intrusive).
   997 
   998 * Antiquotation @{lemma A method} proves proposition A by the given
   999 method (either a method name or a method name plus (optional) method
  1000 arguments in parentheses) and prints A just like @{prop A}.
  1001 
  1002 
  1003 *** HOL ***
  1004 
  1005 * New primrec package.  Specification syntax conforms in style to
  1006 definition/function/....  No separate induction rule is provided.  The
  1007 "primrec" command distinguishes old-style and new-style specifications
  1008 by syntax.  The former primrec package is now named OldPrimrecPackage.
  1009 When adjusting theories, beware: constants stemming from new-style
  1010 primrec specifications have authentic syntax.
  1011 
  1012 * Metis prover is now an order of magnitude faster, and also works
  1013 with multithreading.
  1014 
  1015 * Metis: the maximum number of clauses that can be produced from a
  1016 theorem is now given by the attribute max_clauses.  Theorems that
  1017 exceed this number are ignored, with a warning printed.
  1018 
  1019 * Sledgehammer no longer produces structured proofs by default. To
  1020 enable, declare [[sledgehammer_full = true]].  Attributes
  1021 reconstruction_modulus, reconstruction_sorts renamed
  1022 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
  1023 
  1024 * Method "induct_scheme" derives user-specified induction rules
  1025 from well-founded induction and completeness of patterns. This factors
  1026 out some operations that are done internally by the function package
  1027 and makes them available separately.  See
  1028 src/HOL/ex/Induction_Scheme.thy for examples.
  1029 
  1030 * More flexible generation of measure functions for termination
  1031 proofs: Measure functions can be declared by proving a rule of the
  1032 form "is_measure f" and giving it the [measure_function] attribute.
  1033 The "is_measure" predicate is logically meaningless (always true), and
  1034 just guides the heuristic.  To find suitable measure functions, the
  1035 termination prover sets up the goal "is_measure ?f" of the appropriate
  1036 type and generates all solutions by prolog-style backwards proof using
  1037 the declared rules.
  1038 
  1039 This setup also deals with rules like 
  1040 
  1041   "is_measure f ==> is_measure (list_size f)"
  1042 
  1043 which accommodates nested datatypes that recurse through lists.
  1044 Similar rules are predeclared for products and option types.
  1045 
  1046 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
  1047 
  1048   INCOMPATIBILITIES:
  1049 
  1050   - Definitions of overloaded constants on sets have to be replaced by
  1051     definitions on => and bool.
  1052 
  1053   - Some definitions of overloaded operators on sets can now be proved
  1054     using the definitions of the operators on => and bool.  Therefore,
  1055     the following theorems have been renamed:
  1056 
  1057       subset_def   -> subset_eq
  1058       psubset_def  -> psubset_eq
  1059       set_diff_def -> set_diff_eq
  1060       Compl_def    -> Compl_eq
  1061       Sup_set_def  -> Sup_set_eq
  1062       Inf_set_def  -> Inf_set_eq
  1063       sup_set_def  -> sup_set_eq
  1064       inf_set_def  -> inf_set_eq
  1065 
  1066   - Due to the incompleteness of the HO unification algorithm, some
  1067     rules such as subst may require manual instantiation, if some of
  1068     the unknowns in the rule is a set.
  1069 
  1070   - Higher order unification and forward proofs:
  1071     The proof pattern
  1072 
  1073       have "P (S::'a set)" <...>
  1074       then have "EX S. P S" ..
  1075 
  1076     no longer works (due to the incompleteness of the HO unification
  1077     algorithm) and must be replaced by the pattern
  1078 
  1079       have "EX S. P S"
  1080       proof
  1081         show "P S" <...>
  1082       qed
  1083 
  1084   - Calculational reasoning with subst (or similar rules):
  1085     The proof pattern
  1086 
  1087       have "P (S::'a set)" <...>
  1088       also have "S = T" <...>
  1089       finally have "P T" .
  1090 
  1091     no longer works (for similar reasons as the previous example) and
  1092     must be replaced by something like
  1093 
  1094       have "P (S::'a set)" <...>
  1095       moreover have "S = T" <...>
  1096       ultimately have "P T" by simp
  1097 
  1098   - Tactics or packages written in ML code:
  1099     Code performing pattern matching on types via
  1100 
  1101       Type ("set", [T]) => ...
  1102 
  1103     must be rewritten. Moreover, functions like strip_type or
  1104     binder_types no longer return the right value when applied to a
  1105     type of the form
  1106 
  1107       T1 => ... => Tn => U => bool
  1108 
  1109     rather than
  1110 
  1111       T1 => ... => Tn => U set
  1112 
  1113 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1114 Wellfounded_Relations to theory Wellfounded.
  1115 
  1116 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1117 
  1118 * Class finite no longer treats UNIV as class parameter.  Use class
  1119 enum from theory Library/Enum instead to achieve a similar effect.
  1120 INCOMPATIBILITY.
  1121 
  1122 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1123 and "Cons".  INCOMPATIBILITY.
  1124 
  1125 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1126 Potential INCOMPATIBILITY.
  1127 
  1128 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1129 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1130 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1131 
  1132 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1133 the same name in theory Orderings:
  1134 
  1135   less_trans
  1136   less_linear
  1137   le_imp_less_or_eq
  1138   le_less_trans
  1139   less_le_trans
  1140   less_not_sym
  1141   less_asym
  1142 
  1143 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1144 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1145 and different variable names.
  1146 
  1147 * Library/Option_ord.thy: Canonical order on option type.
  1148 
  1149 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1150 finite maps.
  1151 
  1152 * Library/Countable.thy: Type class for countable types.
  1153 
  1154 * Theory Int: The representation of numerals has changed.  The infix
  1155 operator BIT and the bit datatype with constructors B0 and B1 have
  1156 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1157 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1158 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1159 accordingly.
  1160 
  1161 * Theory Nat: definition of <= and < on natural numbers no longer
  1162 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1163 le_def and less_def have disappeared.  Consider lemmas not_less
  1164 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1165 
  1166 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1167 (whose purpose mainly is for various fold_set functionals) have been
  1168 abandoned in favor of the existing algebraic classes
  1169 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1170 lower_semilattice (resp. upper_semilattice) and linorder.
  1171 INCOMPATIBILITY.
  1172 
  1173 * Theory Transitive_Closure: induct and cases rules now declare proper
  1174 case_names ("base" and "step").  INCOMPATIBILITY.
  1175 
  1176 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1177 lattices.  The form set-specific version is available as
  1178 Inductive.lfp_ordinal_induct_set.
  1179 
  1180 * Renamed theorems "power.simps" to "power_int.simps".
  1181 INCOMPATIBILITY.
  1182 
  1183 * Class semiring_div provides basic abstract properties of semirings
  1184 with division and modulo operations.  Subsumes former class dvd_mod.
  1185 
  1186 * Merged theories IntDef, Numeral and IntArith into unified theory
  1187 Int.  INCOMPATIBILITY.
  1188 
  1189 * Theory Library/Code_Index: type "index" now represents natural
  1190 numbers rather than integers.  INCOMPATIBILITY.
  1191 
  1192 * New class "uminus" with operation "uminus" (split of from class
  1193 "minus" which now only has operation "minus", binary).
  1194 INCOMPATIBILITY.
  1195 
  1196 * Constants "card", "internal_split", "option_map" now with authentic
  1197 syntax.  INCOMPATIBILITY.
  1198 
  1199 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1200 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1201 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1202 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1203 Sup_set_def, le_def, less_def, option_map_def now with object
  1204 equality.  INCOMPATIBILITY.
  1205 
  1206 * Records. Removed K_record, and replaced it by pure lambda term
  1207 %x. c. The simplifier setup is now more robust against eta expansion.
  1208 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1209 
  1210 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1211 
  1212 * Library/ListVector: new theory of arithmetic vector operations.
  1213 
  1214 * Library/Order_Relation: new theory of various orderings as sets of
  1215 pairs.  Defines preorders, partial orders, linear orders and
  1216 well-orders on sets and on types.
  1217 
  1218 
  1219 *** ZF ***
  1220 
  1221 * Renamed some theories to allow to loading both ZF and HOL in the
  1222 same session:
  1223 
  1224   Datatype  -> Datatype_ZF
  1225   Inductive -> Inductive_ZF
  1226   Int       -> Int_ZF
  1227   IntDiv    -> IntDiv_ZF
  1228   Nat       -> Nat_ZF
  1229   List      -> List_ZF
  1230   Main      -> Main_ZF
  1231 
  1232 INCOMPATIBILITY: ZF theories that import individual theories below
  1233 Main might need to be adapted.  Regular theory Main is still
  1234 available, as trivial extension of Main_ZF.
  1235 
  1236 
  1237 *** ML ***
  1238 
  1239 * ML within Isar: antiquotation @{const name} or @{const
  1240 name(typargs)} produces statically-checked Const term.
  1241 
  1242 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1243 (of the same name).  Removed obsolete print command.
  1244 
  1245 * Removed obsolete "use_legacy_bindings" function.
  1246 
  1247 * The ``print mode'' is now a thread-local value derived from a global
  1248 template (the former print_mode reference), thus access becomes
  1249 non-critical.  The global print_mode reference is for session
  1250 management only; user-code should use print_mode_value,
  1251 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1252 
  1253 * Functions system/system_out provide a robust way to invoke external
  1254 shell commands, with propagation of interrupts (requires Poly/ML
  1255 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1256 
  1257 
  1258 *** System ***
  1259 
  1260 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1261 in accordance with Proof General 3.7, which prefers GNU emacs.
  1262 
  1263 * isatool tty runs Isabelle process with plain tty interaction;
  1264 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1265 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1266 
  1267 * isatool browser now works with Cygwin as well, using general
  1268 "javapath" function defined in Isabelle process environment.
  1269 
  1270 * YXML notation provides a simple and efficient alternative to
  1271 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1272 isatool yxml as described in the Isabelle system manual.
  1273 
  1274 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1275 provides general wrapper for managing an Isabelle process in a robust
  1276 fashion, with ``cooked'' output from stdin/stderr.
  1277 
  1278 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1279 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1280 
  1281 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1282 way of changing the user's settings is via
  1283 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1284 script.
  1285 
  1286 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1287 cores of the underlying machine, which is a good starting point for
  1288 optimal performance tuning.  The corresponding usedir option -M allows
  1289 "max" as an alias for "0".  WARNING: does not work on certain versions
  1290 of Mac OS (with Poly/ML 5.1).
  1291 
  1292 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1293 adverse effect of Isabelle flooding interactive front-ends (notably
  1294 ProofGeneral / XEmacs).
  1295 
  1296 
  1297 
  1298 New in Isabelle2007 (November 2007)
  1299 -----------------------------------
  1300 
  1301 *** General ***
  1302 
  1303 * More uniform information about legacy features, notably a
  1304 warning/error of "Legacy feature: ...", depending on the state of the
  1305 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1306 legacy features will disappear eventually.
  1307 
  1308 * Theory syntax: the header format ``theory A = B + C:'' has been
  1309 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1310 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1311 
  1312 * Theory syntax: the old non-Isar theory file format has been
  1313 discontinued altogether.  Note that ML proof scripts may still be used
  1314 with Isar theories; migration is usually quite simple with the ML
  1315 function use_legacy_bindings.  INCOMPATIBILITY.
  1316 
  1317 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1318 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1319 quotes.
  1320 
  1321 * Theory loader: be more serious about observing the static theory
  1322 header specifications (including optional directories), but not the
  1323 accidental file locations of previously successful loads.  The strict
  1324 update policy of former update_thy is now already performed by
  1325 use_thy, so the former has been removed; use_thys updates several
  1326 theories simultaneously, just as 'imports' within a theory header
  1327 specification, but without merging the results.  Potential
  1328 INCOMPATIBILITY: may need to refine theory headers and commands
  1329 ROOT.ML which depend on load order.
  1330 
  1331 * Theory loader: optional support for content-based file
  1332 identification, instead of the traditional scheme of full physical
  1333 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1334 (cf. the system manual).  The new scheme allows to work with
  1335 non-finished theories in persistent session images, such that source
  1336 files may be moved later on without requiring reloads.
  1337 
  1338 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1339 file (with the same base name as the theory) are considered a legacy
  1340 feature, which will disappear eventually. Even now, the theory loader
  1341 no longer maintains dependencies on such files.
  1342 
  1343 * Syntax: the scope for resolving ambiguities via type-inference is
  1344 now limited to individual terms, instead of whole simultaneous
  1345 specifications as before. This greatly reduces the complexity of the
  1346 syntax module and improves flexibility by separating parsing and
  1347 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1348 'fixes' etc.) are required in rare situations.
  1349 
  1350 * Syntax: constants introduced by new-style packages ('definition',
  1351 'abbreviation' etc.) are passed through the syntax module in
  1352 ``authentic mode''. This means that associated mixfix annotations
  1353 really stick to such constants, independently of potential name space
  1354 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1355 trees are represented slightly differently, may need to adapt syntax
  1356 translations accordingly. Use CONST marker in 'translations' and
  1357 @{const_syntax} antiquotation in 'parse_translation' etc.
  1358 
  1359 * Legacy goal package: reduced interface to the bare minimum required
  1360 to keep existing proof scripts running.  Most other user-level
  1361 functions are now part of the OldGoals structure, which is *not* open
  1362 by default (consider isatool expandshort before open OldGoals).
  1363 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1364 these tend to cause confusion about the actual goal (!) context being
  1365 used here, which is not necessarily the same as the_context().
  1366 
  1367 * Command 'find_theorems': supports "*" wild-card in "name:"
  1368 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1369 support a specific search form (see ProofGeneral/CHANGES).
  1370 
  1371 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1372 by default, which means that "prems" (and also "fixed variables") are
  1373 suppressed from proof state output.  Note that the ProofGeneral
  1374 settings mechanism allows to change and save options persistently, but
  1375 older versions of Isabelle will fail to start up if a negative prems
  1376 limit is imposed.
  1377 
  1378 * Local theory targets may be specified by non-nested blocks of
  1379 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1380 contain definitions, theorems etc., including any derived mechanism
  1381 that has been implemented on top of these primitives.  This concept
  1382 generalizes the existing ``theorem (in ...)'' towards more versatility
  1383 and scalability.
  1384 
  1385 * Proof General interface: proper undo of final 'end' command;
  1386 discontinued Isabelle/classic mode (ML proof scripts).
  1387 
  1388 
  1389 *** Document preparation ***
  1390 
  1391 * Added antiquotation @{theory name} which prints the given name,
  1392 after checking that it refers to a valid ancestor theory in the
  1393 current context.
  1394 
  1395 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1396 check the given source text as ML type/structure, printing verbatim.
  1397 
  1398 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1399 "c args == rhs" given in the current context.  (Any number of
  1400 arguments may be given on the LHS.)
  1401 
  1402 
  1403 *** Pure ***
  1404 
  1405 * The 'class' package offers a combination of axclass and locale to
  1406 achieve Haskell-like type classes in Isabelle.  Definitions and
  1407 theorems within a class context produce both relative results (with
  1408 implicit parameters according to the locale context), and polymorphic
  1409 constants with qualified polymorphism (according to the class
  1410 context).  Within the body context of a 'class' target, a separate
  1411 syntax layer ("user space type system") takes care of converting
  1412 between global polymorphic consts and internal locale representation.
  1413 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1414 "isatool doc classes" provides a tutorial.
  1415 
  1416 * Generic code generator framework allows to generate executable
  1417 code for ML and Haskell (including Isabelle classes).  A short usage
  1418 sketch:
  1419 
  1420     internal compilation:
  1421         export_code <list of constants (term syntax)> in SML
  1422     writing SML code to a file:
  1423         export_code <list of constants (term syntax)> in SML <filename>
  1424     writing OCaml code to a file:
  1425         export_code <list of constants (term syntax)> in OCaml <filename>
  1426     writing Haskell code to a bunch of files:
  1427         export_code <list of constants (term syntax)> in Haskell <filename>
  1428 
  1429     evaluating closed propositions to True/False using code generation:
  1430         method ``eval''
  1431 
  1432 Reasonable default setup of framework in HOL.
  1433 
  1434 Theorem attributs for selecting and transforming function equations theorems:
  1435 
  1436     [code fun]:        select a theorem as function equation for a specific constant
  1437     [code fun del]:    deselect a theorem as function equation for a specific constant
  1438     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1439     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1440 
  1441 User-defined serializations (target in {SML, OCaml, Haskell}):
  1442 
  1443     code_const <and-list of constants (term syntax)>
  1444       {(target) <and-list of const target syntax>}+
  1445 
  1446     code_type <and-list of type constructors>
  1447       {(target) <and-list of type target syntax>}+
  1448 
  1449     code_instance <and-list of instances>
  1450       {(target)}+
  1451         where instance ::= <type constructor> :: <class>
  1452 
  1453     code_class <and_list of classes>
  1454       {(target) <and-list of class target syntax>}+
  1455         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1456 
  1457 code_instance and code_class only are effective to target Haskell.
  1458 
  1459 For example usage see src/HOL/ex/Codegenerator.thy and
  1460 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1461 generation from Isabelle/HOL theories is available via "isatool doc
  1462 codegen".
  1463 
  1464 * Code generator: consts in 'consts_code' Isar commands are now
  1465 referred to by usual term syntax (including optional type
  1466 annotations).
  1467 
  1468 * Command 'no_translations' removes translation rules from theory
  1469 syntax.
  1470 
  1471 * Overloaded definitions are now actually checked for acyclic
  1472 dependencies.  The overloading scheme is slightly more general than
  1473 that of Haskell98, although Isabelle does not demand an exact
  1474 correspondence to type class and instance declarations.
  1475 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1476 exotic versions of overloading -- at the discretion of the user!
  1477 
  1478 Polymorphic constants are represented via type arguments, i.e. the
  1479 instantiation that matches an instance against the most general
  1480 declaration given in the signature.  For example, with the declaration
  1481 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1482 as c(nat).  Overloading is essentially simultaneous structural
  1483 recursion over such type arguments.  Incomplete specification patterns
  1484 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1485 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1486 Command 'print_theory' outputs the normalized system of recursive
  1487 equations, see section "definitions".
  1488 
  1489 * Configuration options are maintained within the theory or proof
  1490 context (with name and type bool/int/string), providing a very simple
  1491 interface to a poor-man's version of general context data.  Tools may
  1492 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1493 these values using Config.get etc.  Users may change options via an
  1494 associated attribute of the same name.  This form of context
  1495 declaration works particularly well with commands 'declare' or
  1496 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1497 very easy to avoid global references, which would not observe Isar
  1498 toplevel undo/redo and fail to work with multithreading.
  1499 
  1500 Various global ML references of Pure and HOL have been turned into
  1501 configuration options:
  1502 
  1503   Unify.search_bound		unify_search_bound
  1504   Unify.trace_bound		unify_trace_bound
  1505   Unify.trace_simp		unify_trace_simp
  1506   Unify.trace_types		unify_trace_types
  1507   Simplifier.simp_depth_limit	simp_depth_limit
  1508   Blast.depth_limit		blast_depth_limit
  1509   DatatypeProp.dtK		datatype_distinctness_limit
  1510   fast_arith_neq_limit  	fast_arith_neq_limit
  1511   fast_arith_split_limit	fast_arith_split_limit
  1512 
  1513 * Named collections of theorems may be easily installed as context
  1514 data using the functor NamedThmsFun (see also
  1515 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1516 attributes; there is also a toplevel print command.  This facility is
  1517 just a common case of general context data, which is the preferred way
  1518 for anything more complex than just a list of facts in canonical
  1519 order.
  1520 
  1521 * Isar: command 'declaration' augments a local theory by generic
  1522 declaration functions written in ML.  This enables arbitrary content
  1523 being added to the context, depending on a morphism that tells the
  1524 difference of the original declaration context wrt. the application
  1525 context encountered later on.
  1526 
  1527 * Isar: proper interfaces for simplification procedures.  Command
  1528 'simproc_setup' declares named simprocs (with match patterns, and body
  1529 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1530 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1531 
  1532 * Isar: an extra pair of brackets around attribute declarations
  1533 abbreviates a theorem reference involving an internal dummy fact,
  1534 which will be ignored later --- only the effect of the attribute on
  1535 the background context will persist.  This form of in-place
  1536 declarations is particularly useful with commands like 'declare' and
  1537 'using', for example ``have A using [[simproc a]] by simp''.
  1538 
  1539 * Isar: method "assumption" (and implicit closing of subproofs) now
  1540 takes simple non-atomic goal assumptions into account: after applying
  1541 an assumption as a rule the resulting subgoals are solved by atomic
  1542 assumption steps.  This is particularly useful to finish 'obtain'
  1543 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1544 without referring to the original premise "!!x. P x ==> thesis" in the
  1545 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1546 more permissive.
  1547 
  1548 * Isar: implicit use of prems from the Isar proof context is
  1549 considered a legacy feature.  Common applications like ``have A .''
  1550 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1551 referencing facts explicitly here improves readability and
  1552 maintainability of proof texts.
  1553 
  1554 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1555 the obtained context from the course of reasoning!  For example:
  1556 
  1557   assume "EX x y. A x & B y"   -- "any previous fact"
  1558   then guess x and y by clarify
  1559 
  1560 This technique is potentially adventurous, depending on the facts and
  1561 proof tools being involved here.
  1562 
  1563 * Isar: known facts from the proof context may be specified as literal
  1564 propositions, using ASCII back-quote syntax.  This works wherever
  1565 named facts used to be allowed so far, in proof commands, proof
  1566 methods, attributes etc.  Literal facts are retrieved from the context
  1567 according to unification of type and term parameters.  For example,
  1568 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1569 theorems in the current context, then these are valid literal facts:
  1570 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1571 
  1572 There is also a proof method "fact" which does the same composition
  1573 for explicit goal states, e.g. the following proof texts coincide with
  1574 certain special cases of literal facts:
  1575 
  1576   have "A" by fact                 ==  note `A`
  1577   have "A ==> B" by fact           ==  note `A ==> B`
  1578   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1579   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1580 
  1581 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1582 outer syntax.  Thus symbolic identifiers may be used without
  1583 additional white space in declarations like this: ``assume *: A''.
  1584 
  1585 * Isar: 'print_facts' prints all local facts of the current context,
  1586 both named and unnamed ones.
  1587 
  1588 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1589 
  1590   def x == "t" and y == "u"
  1591 
  1592 * Isar: added command 'unfolding', which is structurally similar to
  1593 'using', but affects both the goal state and facts by unfolding given
  1594 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1595 'unfolded' attribute may be replaced by first-class proof text.
  1596 
  1597 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1598 and command 'unfolding' now all support object-level equalities
  1599 (potentially conditional).  The underlying notion of rewrite rule is
  1600 analogous to the 'rule_format' attribute, but *not* that of the
  1601 Simplifier (which is usually more generous).
  1602 
  1603 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1604 premises of a theorem by n. Useful in conjunction with drule.
  1605 
  1606 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1607 method expression within a sandbox consisting of the first N
  1608 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1609 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1610 simplifies all new goals that emerge from applying rule foo to the
  1611 originally first one.
  1612 
  1613 * Isar: schematic goals are no longer restricted to higher-order
  1614 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1615 expected.
  1616 
  1617 * Isar: the conclusion of a long theorem statement is now either
  1618 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1619 (essentially a disjunction of cases with local parameters and
  1620 assumptions).  The latter allows to express general elimination rules
  1621 adequately; in this notation common elimination rules look like this:
  1622 
  1623   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1624     assumes "EX x. P x"
  1625     obtains x where "P x"
  1626 
  1627   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1628     assumes "A & B"
  1629     obtains A and B
  1630 
  1631   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1632     assumes "A | B"
  1633     obtains
  1634       A
  1635     | B
  1636 
  1637 The subsequent classical rules even refer to the formal "thesis"
  1638 explicitly:
  1639 
  1640   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1641     obtains "~ thesis"
  1642 
  1643   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1644     obtains "thesis ==> something"
  1645 
  1646 The actual proof of an 'obtains' statement is analogous to that of the
  1647 Isar proof element 'obtain', only that there may be several cases.
  1648 Optional case names may be specified in parentheses; these will be
  1649 available both in the present proof and as annotations in the
  1650 resulting rule, for later use with the 'cases' method (cf. attribute
  1651 case_names).
  1652 
  1653 * Isar: the assumptions of a long theorem statement are available as
  1654 "assms" fact in the proof context.  This is more appropriate than the
  1655 (historical) "prems", which refers to all assumptions of the current
  1656 context, including those from the target locale, proof body etc.
  1657 
  1658 * Isar: 'print_statement' prints theorems from the current theory or
  1659 proof context in long statement form, according to the syntax of a
  1660 top-level lemma.
  1661 
  1662 * Isar: 'obtain' takes an optional case name for the local context
  1663 introduction rule (default "that").
  1664 
  1665 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1666 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1667 to occur.
  1668 
  1669 * Pure: syntax "CONST name" produces a fully internalized constant
  1670 according to the current context.  This is particularly useful for
  1671 syntax translations that should refer to internal constant
  1672 representations independently of name spaces.
  1673 
  1674 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1675 instead of "FOO ". This allows multiple binder declarations to coexist
  1676 in the same context.  INCOMPATIBILITY.
  1677 
  1678 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1679 primitive that also works in a locale context (both for constants and
  1680 fixed variables). Type declaration and internal syntactic representation
  1681 of given constants retrieved from the context. Likewise, the
  1682 'no_notation' command allows to remove given syntax annotations from the
  1683 current context.
  1684 
  1685 * Isar/locales: new derived specification elements 'axiomatization',
  1686 'definition', 'abbreviation', which support type-inference, admit
  1687 object-level specifications (equality, equivalence).  See also the
  1688 isar-ref manual.  Examples:
  1689 
  1690   axiomatization
  1691     eq  (infix "===" 50) where
  1692     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1693 
  1694   definition "f x y = x + y + 1"
  1695   definition g where "g x = f x x"
  1696 
  1697   abbreviation
  1698     neq  (infix "=!=" 50) where
  1699     "x =!= y == ~ (x === y)"
  1700 
  1701 These specifications may be also used in a locale context.  Then the
  1702 constants being introduced depend on certain fixed parameters, and the
  1703 constant name is qualified by the locale base name.  An internal
  1704 abbreviation takes care for convenient input and output, making the
  1705 parameters implicit and using the original short name.  See also
  1706 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1707 entities from a monomorphic theory.
  1708 
  1709 Presently, abbreviations are only available 'in' a target locale, but
  1710 not inherited by general import expressions.  Also note that
  1711 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1712 'translations' in common applications.  The "no_abbrevs" print mode
  1713 prevents folding of abbreviations in term output.
  1714 
  1715 Concrete syntax is attached to specified constants in internal form,
  1716 independently of name spaces.  The parse tree representation is
  1717 slightly different -- use 'notation' instead of raw 'syntax', and
  1718 'translations' with explicit "CONST" markup to accommodate this.
  1719 
  1720 * Pure/Isar: unified syntax for new-style specification mechanisms
  1721 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1722 full type inference and dummy patterns ("_").  For example:
  1723 
  1724   definition "K x _ = x"
  1725 
  1726   inductive conj for A B
  1727   where "A ==> B ==> conj A B"
  1728 
  1729 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1730 the current context.  Print mode "no_abbrevs" prevents inversion of
  1731 abbreviations on output.
  1732 
  1733 * Isar/locales: improved parameter handling: use of locales "var" and
  1734 "struct" no longer necessary; - parameter renamings are no longer
  1735 required to be injective.  For example, this allows to define
  1736 endomorphisms as locale endom = homom mult mult h.
  1737 
  1738 * Isar/locales: changed the way locales with predicates are defined.
  1739 Instead of accumulating the specification, the imported expression is
  1740 now an interpretation.  INCOMPATIBILITY: different normal form of
  1741 locale expressions.  In particular, in interpretations of locales with
  1742 predicates, goals repesenting already interpreted fragments are not
  1743 removed automatically.  Use methods `intro_locales' and
  1744 `unfold_locales'; see below.
  1745 
  1746 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1747 provide backward reasoning on locales predicates.  The methods are
  1748 aware of interpretations and discharge corresponding goals.
  1749 `intro_locales' is less aggressive then `unfold_locales' and does not
  1750 unfold predicates to assumptions.
  1751 
  1752 * Isar/locales: the order in which locale fragments are accumulated
  1753 has changed.  This enables to override declarations from fragments due
  1754 to interpretations -- for example, unwanted simp rules.
  1755 
  1756 * Isar/locales: interpretation in theories and proof contexts has been
  1757 extended.  One may now specify (and prove) equations, which are
  1758 unfolded in interpreted theorems.  This is useful for replacing
  1759 defined concepts (constants depending on locale parameters) by
  1760 concepts already existing in the target context.  Example:
  1761 
  1762   interpretation partial_order ["op <= :: [int, int] => bool"]
  1763     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1764 
  1765 Typically, the constant `partial_order.less' is created by a
  1766 definition specification element in the context of locale
  1767 partial_order.
  1768 
  1769 * Method "induct": improved internal context management to support
  1770 local fixes and defines on-the-fly. Thus explicit meta-level
  1771 connectives !!  and ==> are rarely required anymore in inductive goals
  1772 (using object-logic connectives for this purpose has been long
  1773 obsolete anyway). Common proof patterns are explained in
  1774 src/HOL/Induct/Common_Patterns.thy, see also
  1775 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1776 examples.
  1777 
  1778 * Method "induct": improved handling of simultaneous goals. Instead of
  1779 introducing object-level conjunction, the statement is now split into
  1780 several conclusions, while the corresponding symbolic cases are nested
  1781 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1782 see src/HOL/Induct/Common_Patterns.thy, for example.
  1783 
  1784 * Method "induct": mutual induction rules are now specified as a list
  1785 of rule sharing the same induction cases. HOL packages usually provide
  1786 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1787 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1788 mutual induction rules differently, i.e. like this:
  1789 
  1790   (induct rule: foo_bar.inducts)
  1791   (induct set: foo bar)
  1792   (induct pred: foo bar)
  1793   (induct type: foo bar)
  1794 
  1795 The ML function ProjectRule.projections turns old-style rules into the
  1796 new format.
  1797 
  1798 * Method "coinduct": dual of induction, see
  1799 src/HOL/Library/Coinductive_List.thy for various examples.
  1800 
  1801 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1802 considered a legacy feature.
  1803 
  1804 * Attribute "symmetric" produces result with standardized schematic
  1805 variables (index 0).  Potential INCOMPATIBILITY.
  1806 
  1807 * Simplifier: by default the simplifier trace only shows top level
  1808 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1809 default. Thus there is less danger of being flooded by the trace. The
  1810 trace indicates where parts have been suppressed.
  1811   
  1812 * Provers/classical: removed obsolete classical version of elim_format
  1813 attribute; classical elim/dest rules are now treated uniformly when
  1814 manipulating the claset.
  1815 
  1816 * Provers/classical: stricter checks to ensure that supplied intro,
  1817 dest and elim rules are well-formed; dest and elim rules must have at
  1818 least one premise.
  1819 
  1820 * Provers/classical: attributes dest/elim/intro take an optional
  1821 weight argument for the rule (just as the Pure versions).  Weights are
  1822 ignored by automated tools, but determine the search order of single
  1823 rule steps.
  1824 
  1825 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1826 where the body does not mention the bound variable.  Note that dummy
  1827 patterns implicitly depend on their context of bounds, which makes
  1828 "{_. _}" match any set comprehension as expected.  Potential
  1829 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1830 constant "_idtdummy" in the binding position.
  1831 
  1832 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1833 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1834 for example "A -> B" => "Pi A (%_. B)".
  1835 
  1836 * Pure: 'class_deps' command visualizes the subclass relation, using
  1837 the graph browser tool.
  1838 
  1839 * Pure: 'print_theory' now suppresses certain internal declarations by
  1840 default; use '!' option for full details.
  1841 
  1842 
  1843 *** HOL ***
  1844 
  1845 * Method "metis" proves goals by applying the Metis general-purpose
  1846 resolution prover (see also http://gilith.com/software/metis/).
  1847 Examples are in the directory MetisExamples.  WARNING: the
  1848 Isabelle/HOL-Metis integration does not yet work properly with
  1849 multi-threading.
  1850   
  1851 * Command 'sledgehammer' invokes external automatic theorem provers as
  1852 background processes.  It generates calls to the "metis" method if
  1853 successful. These can be pasted into the proof.  Users do not have to
  1854 wait for the automatic provers to return.  WARNING: does not really
  1855 work with multi-threading.
  1856 
  1857 * New "auto_quickcheck" feature tests outermost goal statements for
  1858 potential counter-examples.  Controlled by ML references
  1859 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1860 5000 milliseconds).  Fails silently if statements is outside of
  1861 executable fragment, or any other codgenerator problem occurs.
  1862 
  1863 * New constant "undefined" with axiom "undefined x = undefined".
  1864 
  1865 * Added class "HOL.eq", allowing for code generation with polymorphic
  1866 equality.
  1867 
  1868 * Some renaming of class constants due to canonical name prefixing in
  1869 the new 'class' package:
  1870 
  1871     HOL.abs ~> HOL.abs_class.abs
  1872     HOL.divide ~> HOL.divide_class.divide
  1873     0 ~> HOL.zero_class.zero
  1874     1 ~> HOL.one_class.one
  1875     op + ~> HOL.plus_class.plus
  1876     op - ~> HOL.minus_class.minus
  1877     uminus ~> HOL.minus_class.uminus
  1878     op * ~> HOL.times_class.times
  1879     op < ~> HOL.ord_class.less
  1880     op <= > HOL.ord_class.less_eq
  1881     Nat.power ~> Power.power_class.power
  1882     Nat.size ~> Nat.size_class.size
  1883     Numeral.number_of ~> Numeral.number_class.number_of
  1884     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1885     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1886     Orderings.min ~> Orderings.ord_class.min
  1887     Orderings.max ~> Orderings.ord_class.max
  1888     Divides.op div ~> Divides.div_class.div
  1889     Divides.op mod ~> Divides.div_class.mod
  1890     Divides.op dvd ~> Divides.div_class.dvd
  1891 
  1892 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1893 
  1894 a) User-defined constants using any of the names "plus", "minus",
  1895 "times", "less" or "less_eq". The standard syntax translations for
  1896 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1897 names.
  1898 
  1899 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1900 INCOMPATIBILITY: use more specific names.
  1901 
  1902 c) Permutative equations (e.g. "a + b = b + a")
  1903 Since the change of names also changes the order of terms, permutative
  1904 rewrite rules may get applied in a different order. Experience shows
  1905 that this is rarely the case (only two adaptions in the whole Isabelle
  1906 distribution).  INCOMPATIBILITY: rewrite proofs
  1907 
  1908 d) ML code directly refering to constant names
  1909 This in general only affects hand-written proof tactics, simprocs and
  1910 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1911 Consider using @{const_name} antiquotation.
  1912 
  1913 * New class "default" with associated constant "default".
  1914 
  1915 * Function "sgn" is now overloaded and available on int, real, complex
  1916 (and other numeric types), using class "sgn".  Two possible defs of
  1917 sgn are given as equational assumptions in the classes sgn_if and
  1918 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1919 INCOMPATIBILITY.
  1920 
  1921 * Locale "partial_order" now unified with class "order" (cf. theory
  1922 Orderings), added parameter "less".  INCOMPATIBILITY.
  1923 
  1924 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1925 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1926 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1927 
  1928 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1929 changed order of proof goals in instance proofs.
  1930 
  1931 * The transitivity reasoner for partial and linear orders is set up
  1932 for classes "order" and "linorder".  Instances of the reasoner are available
  1933 in all contexts importing or interpreting the corresponding locales.
  1934 Method "order" invokes the reasoner separately; the reasoner
  1935 is also integrated with the Simplifier as a solver.  Diagnostic
  1936 command 'print_orders' shows the available instances of the reasoner
  1937 in the current context.
  1938 
  1939 * Localized monotonicity predicate in theory "Orderings"; integrated
  1940 lemmas max_of_mono and min_of_mono with this predicate.
  1941 INCOMPATIBILITY.
  1942 
  1943 * Formulation of theorem "dense" changed slightly due to integration
  1944 with new class dense_linear_order.
  1945 
  1946 * Uniform lattice theory development in HOL.
  1947 
  1948     constants "meet" and "join" now named "inf" and "sup"
  1949     constant "Meet" now named "Inf"
  1950 
  1951     classes "meet_semilorder" and "join_semilorder" now named
  1952       "lower_semilattice" and "upper_semilattice"
  1953     class "lorder" now named "lattice"
  1954     class "comp_lat" now named "complete_lattice"
  1955 
  1956     Instantiation of lattice classes allows explicit definitions
  1957     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1958 
  1959   INCOMPATIBILITY.  Theorem renames:
  1960 
  1961     meet_left_le            ~> inf_le1
  1962     meet_right_le           ~> inf_le2
  1963     join_left_le            ~> sup_ge1
  1964     join_right_le           ~> sup_ge2
  1965     meet_join_le            ~> inf_sup_ord
  1966     le_meetI                ~> le_infI
  1967     join_leI                ~> le_supI
  1968     le_meet                 ~> le_inf_iff
  1969     le_join                 ~> ge_sup_conv
  1970     meet_idempotent         ~> inf_idem
  1971     join_idempotent         ~> sup_idem
  1972     meet_comm               ~> inf_commute
  1973     join_comm               ~> sup_commute
  1974     meet_leI1               ~> le_infI1
  1975     meet_leI2               ~> le_infI2
  1976     le_joinI1               ~> le_supI1
  1977     le_joinI2               ~> le_supI2
  1978     meet_assoc              ~> inf_assoc
  1979     join_assoc              ~> sup_assoc
  1980     meet_left_comm          ~> inf_left_commute
  1981     meet_left_idempotent    ~> inf_left_idem
  1982     join_left_comm          ~> sup_left_commute
  1983     join_left_idempotent    ~> sup_left_idem
  1984     meet_aci                ~> inf_aci
  1985     join_aci                ~> sup_aci
  1986     le_def_meet             ~> le_iff_inf
  1987     le_def_join             ~> le_iff_sup
  1988     join_absorp2            ~> sup_absorb2
  1989     join_absorp1            ~> sup_absorb1
  1990     meet_absorp1            ~> inf_absorb1
  1991     meet_absorp2            ~> inf_absorb2
  1992     meet_join_absorp        ~> inf_sup_absorb
  1993     join_meet_absorp        ~> sup_inf_absorb
  1994     distrib_join_le         ~> distrib_sup_le
  1995     distrib_meet_le         ~> distrib_inf_le
  1996 
  1997     add_meet_distrib_left   ~> add_inf_distrib_left
  1998     add_join_distrib_left   ~> add_sup_distrib_left
  1999     is_join_neg_meet        ~> is_join_neg_inf
  2000     is_meet_neg_join        ~> is_meet_neg_sup
  2001     add_meet_distrib_right  ~> add_inf_distrib_right
  2002     add_join_distrib_right  ~> add_sup_distrib_right
  2003     add_meet_join_distribs  ~> add_sup_inf_distribs
  2004     join_eq_neg_meet        ~> sup_eq_neg_inf
  2005     meet_eq_neg_join        ~> inf_eq_neg_sup
  2006     add_eq_meet_join        ~> add_eq_inf_sup
  2007     meet_0_imp_0            ~> inf_0_imp_0
  2008     join_0_imp_0            ~> sup_0_imp_0
  2009     meet_0_eq_0             ~> inf_0_eq_0
  2010     join_0_eq_0             ~> sup_0_eq_0
  2011     neg_meet_eq_join        ~> neg_inf_eq_sup
  2012     neg_join_eq_meet        ~> neg_sup_eq_inf
  2013     join_eq_if              ~> sup_eq_if
  2014 
  2015     mono_meet               ~> mono_inf
  2016     mono_join               ~> mono_sup
  2017     meet_bool_eq            ~> inf_bool_eq
  2018     join_bool_eq            ~> sup_bool_eq
  2019     meet_fun_eq             ~> inf_fun_eq
  2020     join_fun_eq             ~> sup_fun_eq
  2021     meet_set_eq             ~> inf_set_eq
  2022     join_set_eq             ~> sup_set_eq
  2023     meet1_iff               ~> inf1_iff
  2024     meet2_iff               ~> inf2_iff
  2025     meet1I                  ~> inf1I
  2026     meet2I                  ~> inf2I
  2027     meet1D1                 ~> inf1D1
  2028     meet2D1                 ~> inf2D1
  2029     meet1D2                 ~> inf1D2
  2030     meet2D2                 ~> inf2D2
  2031     meet1E                  ~> inf1E
  2032     meet2E                  ~> inf2E
  2033     join1_iff               ~> sup1_iff
  2034     join2_iff               ~> sup2_iff
  2035     join1I1                 ~> sup1I1
  2036     join2I1                 ~> sup2I1
  2037     join1I1                 ~> sup1I1
  2038     join2I2                 ~> sup1I2
  2039     join1CI                 ~> sup1CI
  2040     join2CI                 ~> sup2CI
  2041     join1E                  ~> sup1E
  2042     join2E                  ~> sup2E
  2043 
  2044     is_meet_Meet            ~> is_meet_Inf
  2045     Meet_bool_def           ~> Inf_bool_def
  2046     Meet_fun_def            ~> Inf_fun_def
  2047     Meet_greatest           ~> Inf_greatest
  2048     Meet_lower              ~> Inf_lower
  2049     Meet_set_def            ~> Inf_set_def
  2050 
  2051     Sup_def                 ~> Sup_Inf
  2052     Sup_bool_eq             ~> Sup_bool_def
  2053     Sup_fun_eq              ~> Sup_fun_def
  2054     Sup_set_eq              ~> Sup_set_def
  2055 
  2056     listsp_meetI            ~> listsp_infI
  2057     listsp_meet_eq          ~> listsp_inf_eq
  2058 
  2059     meet_min                ~> inf_min
  2060     join_max                ~> sup_max
  2061 
  2062 * Added syntactic class "size"; overloaded constant "size" now has
  2063 type "'a::size ==> bool"
  2064 
  2065 * Internal reorganisation of `size' of datatypes: size theorems
  2066 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2067 simplification rules by default!); theorems "prod.size" now named
  2068 "*.size".
  2069 
  2070 * Class "div" now inherits from class "times" rather than "type".
  2071 INCOMPATIBILITY.
  2072 
  2073 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2074 Linorder etc.  have disappeared; operations defined in terms of
  2075 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2076 
  2077 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2078 
  2079 * HOL-Word: New extensive library and type for generic, fixed size
  2080 machine words, with arithemtic, bit-wise, shifting and rotating
  2081 operations, reflection into int, nat, and bool lists, automation for
  2082 linear arithmetic (by automatic reflection into nat or int), including
  2083 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2084 arithmetic type classes, supporting automatic simplification of
  2085 numerals on all operations.
  2086 
  2087 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2088 
  2089 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2090 
  2091 * Code generator library theories:
  2092   - Code_Integer represents HOL integers by big integer literals in target
  2093     languages.
  2094   - Code_Char represents HOL characters by character literals in target
  2095     languages.
  2096   - Code_Char_chr like Code_Char, but also offers treatment of character
  2097     codes; includes Code_Integer.
  2098   - Executable_Set allows to generate code for finite sets using lists.
  2099   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2100     denominator).
  2101   - Executable_Real implements a subset of real numbers, namly those
  2102     representable by rational numbers.
  2103   - Efficient_Nat implements natural numbers by integers, which in general will
  2104     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2105     includes Code_Integer.
  2106   - Code_Index provides an additional datatype index which is mapped to
  2107     target-language built-in integers.
  2108   - Code_Message provides an additional datatype message_string which is isomorphic to
  2109     strings; messages are mapped to target-language strings.
  2110 
  2111 * New package for inductive predicates
  2112 
  2113   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2114 
  2115     inductive
  2116       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2117       for z_1 :: U_1 and ... and z_n :: U_m
  2118     where
  2119       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2120     | ...
  2121 
  2122   with full support for type-inference, rather than
  2123 
  2124     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2125 
  2126     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2127     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2128 
  2129     inductive "s z_1 ... z_m"
  2130     intros
  2131       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2132       ...
  2133 
  2134   For backward compatibility, there is a wrapper allowing inductive
  2135   sets to be defined with the new package via
  2136 
  2137     inductive_set
  2138       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2139       for z_1 :: U_1 and ... and z_n :: U_m
  2140     where
  2141       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2142     | ...
  2143 
  2144   or
  2145 
  2146     inductive_set
  2147       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2148       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2149       for z_1 :: U_1 and ... and z_n :: U_m
  2150     where
  2151       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2152     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2153     | ...
  2154 
  2155   if the additional syntax "p ..." is required.
  2156 
  2157   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2158   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2159 
  2160   INCOMPATIBILITIES:
  2161 
  2162   - Since declaration and definition of inductive sets or predicates
  2163     is no longer separated, abbreviations involving the newly
  2164     introduced sets or predicates must be specified together with the
  2165     introduction rules after the 'where' keyword (see above), rather
  2166     than before the actual inductive definition.
  2167 
  2168   - The variables in induction and elimination rules are now
  2169     quantified in the order of their occurrence in the introduction
  2170     rules, rather than in alphabetical order. Since this may break
  2171     some proofs, these proofs either have to be repaired, e.g. by
  2172     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2173     statements of the form
  2174 
  2175       case (rule_i a_i_1 ... a_i_{k_i})
  2176 
  2177     or the old order of quantification has to be restored by explicitly adding
  2178     meta-level quantifiers in the introduction rules, i.e.
  2179 
  2180       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2181 
  2182   - The format of the elimination rules is now
  2183 
  2184       p z_1 ... z_m x_1 ... x_n ==>
  2185         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2186         ==> ... ==> P
  2187 
  2188     for predicates and
  2189 
  2190       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2191         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2192         ==> ... ==> P
  2193 
  2194     for sets rather than
  2195 
  2196       x : s z_1 ... z_m ==>
  2197         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2198         ==> ... ==> P
  2199 
  2200     This may require terms in goals to be expanded to n-tuples
  2201     (e.g. using case_tac or simplification with the split_paired_all
  2202     rule) before the above elimination rule is applicable.
  2203 
  2204   - The elimination or case analysis rules for (mutually) inductive
  2205     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2206     list of rules "p_1_..._p_k.elims" is no longer available.
  2207 
  2208 * New package "function"/"fun" for general recursive functions,
  2209 supporting mutual and nested recursion, definitions in local contexts,
  2210 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2211 for small examples, and the separate tutorial on the function
  2212 package. The old recdef "package" is still available as before, but
  2213 users are encouraged to use the new package.
  2214 
  2215 * Method "lexicographic_order" automatically synthesizes termination
  2216 relations as lexicographic combinations of size measures. 
  2217 
  2218 * Case-expressions allow arbitrary constructor-patterns (including
  2219 "_") and take their order into account, like in functional
  2220 programming.  Internally, this is translated into nested
  2221 case-expressions; missing cases are added and mapped to the predefined
  2222 constant "undefined". In complicated cases printing may no longer show
  2223 the original input but the internal form. Lambda-abstractions allow
  2224 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2225 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2226 variable.
  2227 
  2228 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2229 is an abbreviation for "of_nat :: nat => int". The simplification
  2230 rules for "of_nat" have been changed to work like "int" did
  2231 previously.  Potential INCOMPATIBILITY:
  2232   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2233   - of_nat_diff and of_nat_mult are no longer default simp rules
  2234 
  2235 * Method "algebra" solves polynomial equations over (semi)rings using
  2236 Groebner bases. The (semi)ring structure is defined by locales and the
  2237 tool setup depends on that generic context. Installing the method for
  2238 a specific type involves instantiating the locale and possibly adding
  2239 declarations for computation on the coefficients.  The method is
  2240 already instantiated for natural numbers and for the axiomatic class
  2241 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2242 CALCULEMUS 2007 for the general principles underlying this
  2243 architecture of context-aware proof-tools.
  2244 
  2245 * Method "ferrack" implements quantifier elimination over
  2246 special-purpose dense linear orders using locales (analogous to
  2247 "algebra"). The method is already installed for class
  2248 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2249 rat, etc.
  2250 
  2251 * Former constant "List.op @" now named "List.append".  Use ML
  2252 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2253 circumvent possible incompatibilities when working on ML level.
  2254 
  2255 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2256 
  2257 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2258 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2259 
  2260 * New syntax for Haskell-like list comprehension (input only), eg.
  2261 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2262 
  2263 * The special syntax for function "filter" has changed from [x :
  2264 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2265 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2266 
  2267 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2268 defined on nat only, as an abbreviation for [a..<Suc b]
  2269 INCOMPATIBILITY.
  2270 
  2271 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2272 
  2273 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2274 
  2275 * New lemma collection field_simps (an extension of ring_simps) for
  2276 manipulating (in)equations involving division. Multiplies with all
  2277 denominators that can be proved to be non-zero (in equations) or
  2278 positive/negative (in inequations).
  2279 
  2280 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2281 have been improved and renamed to ring_simps, group_simps and
  2282 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2283 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2284 
  2285 * Theory Library/Commutative_Ring: switched from recdef to function
  2286 package; constants add, mul, pow now curried.  Infix syntax for
  2287 algebraic operations.
  2288 
  2289 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2290 INCOMPATIBILITY.
  2291 
  2292 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2293 INCOMPATIBILITY.
  2294 
  2295 * HOL/records: generalised field-update to take a function on the
  2296 field rather than the new value: r(|A := x|) is translated to A_update
  2297 (K x) r The K-combinator that is internally used is called K_record.
  2298 INCOMPATIBILITY: Usage of the plain update functions has to be
  2299 adapted.
  2300  
  2301 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2302 * x = 0, which are required for a semiring.  Richer structures do not
  2303 inherit from semiring_0 anymore, because this property is a theorem
  2304 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2305 there is more to prove, but this is mostly trivial.
  2306 
  2307 * Class "recpower" is generalized to arbitrary monoids, not just
  2308 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2309 commutativity or semiring properties additionally.
  2310 
  2311 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2312 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2313 better use 'abbreviation'.
  2314 
  2315 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2316 
  2317 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2318 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2319 significant changes for setting up numeral syntax for types:
  2320   - New constants Numeral.pred and Numeral.succ instead
  2321       of former Numeral.bin_pred and Numeral.bin_succ.
  2322   - Use integer operations instead of bin_add, bin_mult and so on.
  2323   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2324   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2325 
  2326 See src/HOL/Integ/IntArith.thy for an example setup.
  2327 
  2328 * Command 'normal_form' computes the normal form of a term that may
  2329 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2330 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2331 heavy-duty computations because the functions are compiled to ML
  2332 first.  Correspondingly, a method "normalization" is provided.  See
  2333 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2334 
  2335 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2336 25 like -->); output depends on the "iff" print_mode, the default is
  2337 "A = B" (with priority 50).
  2338 
  2339 * Relations less (<) and less_eq (<=) are also available on type bool.
  2340 Modified syntax to disallow nesting without explicit parentheses,
  2341 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2342 INCOMPATIBILITY.
  2343 
  2344 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2345 
  2346 * Relation composition operator "op O" now has precedence 75 and binds
  2347 stronger than union and intersection. INCOMPATIBILITY.
  2348 
  2349 * The old set interval syntax "{m..n(}" (and relatives) has been
  2350 removed.  Use "{m..<n}" (and relatives) instead.
  2351 
  2352 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2353 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2354 ``declare [[simproc del: neq]]''.
  2355 
  2356 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2357 True/False.
  2358 
  2359 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2360 
  2361 * Theorem setsum_mult renamed to setsum_right_distrib.
  2362 
  2363 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2364 ``rule'' method.
  2365 
  2366 * Reimplemented methods "sat" and "satx", with several improvements:
  2367 goals no longer need to be stated as "<prems> ==> False", equivalences
  2368 (i.e. "=" on type bool) are handled, variable names of the form
  2369 "lit_<n>" are no longer reserved, significant speedup.
  2370 
  2371 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2372 zChaff is still supported as well.
  2373 
  2374 * 'inductive' and 'datatype': provide projections of mutual rules,
  2375 bundled as foo_bar.inducts;
  2376 
  2377 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2378 Library.
  2379 
  2380 * Library: moved theory Accessible_Part to main HOL.
  2381 
  2382 * Library: added theory Coinductive_List of potentially infinite lists
  2383 as greatest fixed-point.
  2384 
  2385 * Library: added theory AssocList which implements (finite) maps as
  2386 association lists.
  2387 
  2388 * Method "evaluation" solves goals (i.e. a boolean expression)
  2389 efficiently by compiling it to ML.  The goal is "proved" (via an
  2390 oracle) if it evaluates to True.
  2391 
  2392 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2393 also when invoked by the simplifier.  This results in the Simplifier
  2394 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2395 Configuration option fast_arith_split_limit=0 recovers the old
  2396 behavior.
  2397 
  2398 * Support for hex (0x20) and binary (0b1001) numerals.
  2399 
  2400 * New method: reify eqs (t), where eqs are equations for an
  2401 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2402 parameter, computes a term s::'b and a list xs::'a list and proves the
  2403 theorem I xs s = t. This is also known as reification or quoting. The
  2404 resulting theorem is applied to the subgoal to substitute t with I xs
  2405 s.  If t is omitted, the subgoal itself is reified.
  2406 
  2407 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2408 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2409 where f is supposed to be a computable function (in the sense of code
  2410 generattion). The method uses reify to compute s and xs as above then
  2411 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2412 r and finally gets the theorem t = r, which is again applied to the
  2413 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2414 
  2415 * Reflection: Automatic reification now handels binding, an example is
  2416 available in src/HOL/ex/ReflectionEx.thy
  2417 
  2418 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2419 command 'statespace' that is similar to 'record', but introduces an
  2420 abstract specification based on the locale infrastructure instead of
  2421 HOL types.  This leads to extra flexibility in composing state spaces,
  2422 in particular multiple inheritance and renaming of components.
  2423 
  2424 
  2425 *** HOL-Complex ***
  2426 
  2427 * Hyperreal: Functions root and sqrt are now defined on negative real
  2428 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2429 Nonnegativity side conditions have been removed from many lemmas, so
  2430 that more subgoals may now be solved by simplification; potential
  2431 INCOMPATIBILITY.
  2432 
  2433 * Real: new type classes formalize real normed vector spaces and
  2434 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2435 and norm :: 'a => real.
  2436 
  2437 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2438 reals into other types. The overloaded constant Reals :: 'a set is now
  2439 defined as range of_real; potential INCOMPATIBILITY.
  2440 
  2441 * Real: proper support for ML code generation, including 'quickcheck'.
  2442 Reals are implemented as arbitrary precision rationals.
  2443 
  2444 * Hyperreal: Several constants that previously worked only for the
  2445 reals have been generalized, so they now work over arbitrary vector
  2446 spaces. Type annotations may need to be added in some cases; potential
  2447 INCOMPATIBILITY.
  2448 
  2449   Infinitesimal  :: ('a::real_normed_vector) star set
  2450   HFinite        :: ('a::real_normed_vector) star set
  2451   HInfinite      :: ('a::real_normed_vector) star set
  2452   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2453   monad          :: ('a::real_normed_vector) star => 'a star set
  2454   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2455   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2456   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2457   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2458   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2459   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2460   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2461   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2462   sgn            :: 'a::real_normed_vector => 'a
  2463   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2464 
  2465 * Complex: Some complex-specific constants are now abbreviations for
  2466 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2467 hnorm.  Other constants have been entirely removed in favor of the
  2468 polymorphic versions (INCOMPATIBILITY):
  2469 
  2470   approx        <-- capprox
  2471   HFinite       <-- CFinite
  2472   HInfinite     <-- CInfinite
  2473   Infinitesimal <-- CInfinitesimal
  2474   monad         <-- cmonad
  2475   galaxy        <-- cgalaxy
  2476   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2477   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2478   (ns)deriv     <-- (ns)cderiv
  2479 
  2480 
  2481 *** HOL-Algebra ***
  2482 
  2483 * Formalisation of ideals and the quotient construction over rings.
  2484 
  2485 * Order and lattice theory no longer based on records.
  2486 INCOMPATIBILITY.
  2487 
  2488 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2489 greatest_closed.  INCOMPATIBILITY.
  2490 
  2491 * Method algebra is now set up via an attribute.  For examples see
  2492 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2493 of algebraic structures.
  2494 
  2495 * Renamed theory CRing to Ring.
  2496 
  2497 
  2498 *** HOL-Nominal ***
  2499 
  2500 * Substantial, yet incomplete support for nominal datatypes (binding
  2501 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2502 src/HOL/Nominal/Examples.  Prospective users should consult
  2503 http://isabelle.in.tum.de/nominal/
  2504 
  2505 
  2506 *** ML ***
  2507 
  2508 * ML basics: just one true type int, which coincides with IntInf.int
  2509 (even on SML/NJ).
  2510 
  2511 * ML within Isar: antiquotations allow to embed statically-checked
  2512 formal entities in the source, referring to the context available at
  2513 compile-time.  For example:
  2514 
  2515 ML {* @{sort "{zero,one}"} *}
  2516 ML {* @{typ "'a => 'b"} *}
  2517 ML {* @{term "%x. x"} *}
  2518 ML {* @{prop "x == y"} *}
  2519 ML {* @{ctyp "'a => 'b"} *}
  2520 ML {* @{cterm "%x. x"} *}
  2521 ML {* @{cprop "x == y"} *}
  2522 ML {* @{thm asm_rl} *}
  2523 ML {* @{thms asm_rl} *}
  2524 ML {* @{type_name c} *}
  2525 ML {* @{type_syntax c} *}
  2526 ML {* @{const_name c} *}
  2527 ML {* @{const_syntax c} *}
  2528 ML {* @{context} *}
  2529 ML {* @{theory} *}
  2530 ML {* @{theory Pure} *}
  2531 ML {* @{theory_ref} *}
  2532 ML {* @{theory_ref Pure} *}
  2533 ML {* @{simpset} *}
  2534 ML {* @{claset} *}
  2535 ML {* @{clasimpset} *}
  2536 
  2537 The same works for sources being ``used'' within an Isar context.
  2538 
  2539 * ML in Isar: improved error reporting; extra verbosity with
  2540 ML_Context.trace enabled.
  2541 
  2542 * Pure/General/table.ML: the join operations now works via exceptions
  2543 DUP/SAME instead of type option. This is simpler in simple cases, and
  2544 admits slightly more efficient complex applications.
  2545 
  2546 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2547 use Context.generic instead of just theory.
  2548 
  2549 * Pure: datatype Context.generic joins theory/Proof.context and
  2550 provides some facilities for code that works in either kind of
  2551 context, notably GenericDataFun for uniform theory and proof data.
  2552 
  2553 * Pure: simplified internal attribute type, which is now always
  2554 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2555 local (Proof.context) attributes have been discontinued, while
  2556 minimizing code duplication. Thm.rule_attribute and
  2557 Thm.declaration_attribute build canonical attributes; see also structure
  2558 Context for further operations on Context.generic, notably
  2559 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2560 declarations and definitions.
  2561 
  2562 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2563 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2564 init only required for impure data. INCOMPATIBILITY: empty really need
  2565 to be empty (no dependencies on theory content!)
  2566 
  2567 * Pure/kernel: consts certification ignores sort constraints given in
  2568 signature declarations. (This information is not relevant to the
  2569 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2570 potential INCOMPATIBILITY.
  2571 
  2572 * Pure: axiomatic type classes are now purely definitional, with
  2573 explicit proofs of class axioms and super class relations performed
  2574 internally. See Pure/axclass.ML for the main internal interfaces --
  2575 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2576 AxClass.axiomatize_class/classrel/arity supersede
  2577 Sign.add_classes/classrel/arities.
  2578 
  2579 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2580 global/local versions on theory vs. Proof.context have been
  2581 discontinued; Attrib.syntax and Method.syntax have been adapted
  2582 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2583 attributes, methods, etc.
  2584 
  2585 * Pure: several functions of signature "... -> theory -> theory * ..."
  2586 have been reoriented to "... -> theory -> ... * theory" in order to
  2587 allow natural usage in combination with the ||>, ||>>, |-> and
  2588 fold_map combinators.
  2589 
  2590 * Pure: official theorem names (closed derivations) and additional
  2591 comments (tags) are now strictly separate.  Name hints -- which are
  2592 maintained as tags -- may be attached any time without affecting the
  2593 derivation.
  2594 
  2595 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2596 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2597 achieve the old behaviour.
  2598 
  2599 * Pure: the "Goal" constant is now called "prop", supporting a
  2600 slightly more general idea of ``protecting'' meta-level rule
  2601 statements.
  2602 
  2603 * Pure: Logic.(un)varify only works in a global context, which is now
  2604 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2605 Logic.legacy_(un)varify as temporary workaround.
  2606 
  2607 * Pure: structure Name provides scalable operations for generating
  2608 internal variable names, notably Name.variants etc.  This replaces
  2609 some popular functions from term.ML:
  2610 
  2611   Term.variant		->  Name.variant
  2612   Term.variantlist	->  Name.variant_list
  2613   Term.invent_names	->  Name.invent_list
  2614 
  2615 Note that low-level renaming rarely occurs in new code -- operations
  2616 from structure Variable are used instead (see below).
  2617 
  2618 * Pure: structure Variable provides fundamental operations for proper
  2619 treatment of fixed/schematic variables in a context.  For example,
  2620 Variable.import introduces fixes for schematics of given facts and
  2621 Variable.export reverses the effect (up to renaming) -- this replaces
  2622 various freeze_thaw operations.
  2623 
  2624 * Pure: structure Goal provides simple interfaces for
  2625 init/conclude/finish and tactical prove operations (replacing former
  2626 Tactic.prove).  Goal.prove is the canonical way to prove results
  2627 within a given context; Goal.prove_global is a degraded version for
  2628 theory level goals, including a global Drule.standard.  Note that
  2629 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2630 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2631 in a locale context).
  2632 
  2633 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2634 and type checking (Syntax.check_term etc.), with common combinations
  2635 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2636 which are considered legacy and await removal.
  2637 
  2638 * Pure/Syntax: generic interfaces for type unchecking
  2639 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2640 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2641 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2642 available for convenience, but refer to the very same operations using
  2643 a mere theory instead of a full context.
  2644 
  2645 * Isar: simplified treatment of user-level errors, using exception
  2646 ERROR of string uniformly.  Function error now merely raises ERROR,
  2647 without any side effect on output channels.  The Isar toplevel takes
  2648 care of proper display of ERROR exceptions.  ML code may use plain
  2649 handle/can/try; cat_error may be used to concatenate errors like this:
  2650 
  2651   ... handle ERROR msg => cat_error msg "..."
  2652 
  2653 Toplevel ML code (run directly or through the Isar toplevel) may be
  2654 embedded into the Isar toplevel with exception display/debug like
  2655 this:
  2656 
  2657   Isar.toplevel (fn () => ...)
  2658 
  2659 INCOMPATIBILITY, removed special transform_error facilities, removed
  2660 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2661 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2662 -- use plain ERROR instead.
  2663 
  2664 * Isar: theory setup now has type (theory -> theory), instead of a
  2665 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2666 
  2667 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2668 ProofContext.debug/verbose flags.
  2669 
  2670 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2671 theory before entering a proof state.  Transactions now always see a
  2672 quasi-functional intermediate checkpoint, both in interactive and
  2673 batch mode.
  2674 
  2675 * Isar: simplified interfaces for outer syntax.  Renamed
  2676 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2677 OuterSyntax.add_parsers -- this functionality is now included in
  2678 OuterSyntax.command etc.  INCOMPATIBILITY.
  2679 
  2680 * Simplifier: the simpset of a running simplification process now
  2681 contains a proof context (cf. Simplifier.the_context), which is the
  2682 very context that the initial simpset has been retrieved from (by
  2683 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2684 (solver, looper etc.) may depend on arbitrary proof data.
  2685 
  2686 * Simplifier.inherit_context inherits the proof context (plus the
  2687 local bounds) of the current simplification process; any simproc
  2688 etc. that calls the Simplifier recursively should do this!  Removed
  2689 former Simplifier.inherit_bounds, which is already included here --
  2690 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2691 specify an explicit context using Simplifier.context/theory_context.
  2692 
  2693 * Simplifier/Classical Reasoner: more abstract interfaces
  2694 change_simpset/claset for modifying the simpset/claset reference of a
  2695 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2696 INCOMPATIBILITY.
  2697 
  2698 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2699 "Trueprop" etc.
  2700 
  2701 
  2702 *** System ***
  2703 
  2704 * settings: the default heap location within ISABELLE_HOME_USER now
  2705 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2706 Isabelle installations.
  2707 
  2708 * isabelle-process: option -S (secure mode) disables some critical
  2709 operations, notably runtime compilation and evaluation of ML source
  2710 code.
  2711 
  2712 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2713 
  2714 * Support for parallel execution, using native multicore support of
  2715 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2716 independent theories, according to the given theory header
  2717 specifications. The maximum number of worker threads is specified via
  2718 usedir option -M or the "max-threads" setting in Proof General. A
  2719 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2720 to 6 on a 8-core machine.  User-code needs to observe certain
  2721 guidelines for thread-safe programming, see appendix A in the Isar
  2722 Implementation manual.
  2723 
  2724 
  2725 
  2726 New in Isabelle2005 (October 2005)
  2727 ----------------------------------
  2728 
  2729 *** General ***
  2730 
  2731 * Theory headers: the new header syntax for Isar theories is
  2732 
  2733   theory <name>
  2734   imports <theory1> ... <theoryN>
  2735   uses <file1> ... <fileM>
  2736   begin
  2737 
  2738 where the 'uses' part is optional.  The previous syntax
  2739 
  2740   theory <name> = <theory1> + ... + <theoryN>:
  2741 
  2742 will disappear in the next release.  Use isatool fixheaders to convert
  2743 existing theory files.  Note that there is no change in ancient
  2744 non-Isar theories now, but these will disappear soon.
  2745 
  2746 * Theory loader: parent theories can now also be referred to via
  2747 relative and absolute paths.
  2748 
  2749 * Command 'find_theorems' searches for a list of criteria instead of a
  2750 list of constants. Known criteria are: intro, elim, dest, name:string,
  2751 simp:term, and any term. Criteria can be preceded by '-' to select
  2752 theorems that do not match. Intro, elim, dest select theorems that
  2753 match the current goal, name:s selects theorems whose fully qualified
  2754 name contain s, and simp:term selects all simplification rules whose
  2755 lhs match term.  Any other term is interpreted as pattern and selects
  2756 all theorems matching the pattern. Available in ProofGeneral under
  2757 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2758 
  2759   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2760 
  2761 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2762 matching the current goal as introduction rule and not having "HOL."
  2763 in their name (i.e. not being defined in theory HOL).
  2764 
  2765 * Command 'thms_containing' has been discontinued in favour of
  2766 'find_theorems'; INCOMPATIBILITY.
  2767 
  2768 * Communication with Proof General is now 8bit clean, which means that
  2769 Unicode text in UTF-8 encoding may be used within theory texts (both
  2770 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2771 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2772 
  2773   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2774   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2775 
  2776 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2777 Classical Reasoner.  Typical big applications run around 2 times
  2778 faster.
  2779 
  2780 
  2781 *** Document preparation ***
  2782 
  2783 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2784 of raw sources.  Only those symbols that do not require additional
  2785 LaTeX packages (depending on comments in isabellesym.sty) are
  2786 displayed properly, everything else is left verbatim.  isatool display
  2787 and isatool print are used as front ends (these are subject to the
  2788 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2789 
  2790 * Command tags control specific markup of certain regions of text,
  2791 notably folding and hiding.  Predefined tags include "theory" (for
  2792 theory begin and end), "proof" for proof commands, and "ML" for
  2793 commands involving ML code; the additional tags "visible" and
  2794 "invisible" are unused by default.  Users may give explicit tag
  2795 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2796 interpretation of tags is determined by the LaTeX job during document
  2797 preparation: see option -V of isatool usedir, or options -n and -t of
  2798 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2799 \isadroptag.
  2800 
  2801 Several document versions may be produced at the same time via isatool
  2802 usedir (the generated index.html will link all of them).  Typical
  2803 specifications include ''-V document=theory,proof,ML'' to present
  2804 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2805 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2806 these parts without any formal replacement text.  The Isabelle site
  2807 default settings produce ''document'' and ''outline'' versions as
  2808 specified above.
  2809 
  2810 * Several new antiquotations:
  2811 
  2812   @{term_type term} prints a term with its type annotated;
  2813 
  2814   @{typeof term} prints the type of a term;
  2815 
  2816   @{const const} is the same as @{term const}, but checks that the
  2817   argument is a known logical constant;
  2818 
  2819   @{term_style style term} and @{thm_style style thm} print a term or
  2820   theorem applying a "style" to it
  2821 
  2822   @{ML text}
  2823 
  2824 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2825 definitions, equations, inequations etc., 'concl' printing only the
  2826 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2827 to print the specified premise.  TermStyle.add_style provides an ML
  2828 interface for introducing further styles.  See also the "LaTeX Sugar"
  2829 document practical applications.  The ML antiquotation prints
  2830 type-checked ML expressions verbatim.
  2831 
  2832 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2833 and 'text' support optional locale specification '(in loc)', which
  2834 specifies the default context for interpreting antiquotations.  For
  2835 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2836 
  2837 * Option 'locale=NAME' of antiquotations specifies an alternative
  2838 context interpreting the subsequent argument.  For example: @{thm
  2839 [locale=lattice] inf_assoc}.
  2840 
  2841 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2842 a proof context.
  2843 
  2844 * Proper output of antiquotations for theory commands involving a
  2845 proof context (such as 'locale' or 'theorem (in loc) ...').
  2846 
  2847 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2848 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2849 
  2850 * isatool usedir: new option -C (default true) controls whether option
  2851 -D should include a copy of the original document directory; -C false
  2852 prevents unwanted effects such as copying of administrative CVS data.
  2853 
  2854 
  2855 *** Pure ***
  2856 
  2857 * Considerably improved version of 'constdefs' command.  Now performs
  2858 automatic type-inference of declared constants; additional support for
  2859 local structure declarations (cf. locales and HOL records), see also
  2860 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2861 sequential dependencies of definitions within a single 'constdefs'
  2862 section; moreover, the declared name needs to be an identifier.  If
  2863 all fails, consider to fall back on 'consts' and 'defs' separately.
  2864 
  2865 * Improved indexed syntax and implicit structures.  First of all,
  2866 indexed syntax provides a notational device for subscripted
  2867 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2868 expressions.  Secondly, in a local context with structure
  2869 declarations, number indexes \<^sub>n or the empty index (default
  2870 number 1) refer to a certain fixed variable implicitly; option
  2871 show_structs controls printing of implicit structures.  Typical
  2872 applications of these concepts involve record types and locales.
  2873 
  2874 * New command 'no_syntax' removes grammar declarations (and
  2875 translations) resulting from the given syntax specification, which is
  2876 interpreted in the same manner as for the 'syntax' command.
  2877 
  2878 * 'Advanced' translation functions (parse_translation etc.) may depend
  2879 on the signature of the theory context being presently used for
  2880 parsing/printing, see also isar-ref manual.
  2881 
  2882 * Improved 'oracle' command provides a type-safe interface to turn an
  2883 ML expression of type theory -> T -> term into a primitive rule of
  2884 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2885 is already included here); see also FOL/ex/IffExample.thy;
  2886 INCOMPATIBILITY.
  2887 
  2888 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2889 before); "cI" is no longer bound, use "c.intro" instead.
  2890 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2891 axclasses vs. locales.
  2892 
  2893 * Improved internal renaming of symbolic identifiers -- attach primes
  2894 instead of base 26 numbers.
  2895 
  2896 * New flag show_question_marks controls printing of leading question
  2897 marks in schematic variable names.
  2898 
  2899 * In schematic variable names, *any* symbol following \<^isub> or
  2900 \<^isup> is now treated as part of the base name.  For example, the
  2901 following works without printing of awkward ".0" indexes:
  2902 
  2903   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2904     by simp
  2905 
  2906 * Inner syntax includes (*(*nested*) comments*).
  2907 
  2908 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2909 annotations as "(00...)".
  2910 
  2911 * Clear separation of logical types and nonterminals, where the latter
  2912 may only occur in 'syntax' specifications or type abbreviations.
  2913 Before that distinction was only partially implemented via type class
  2914 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2915 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2916 exotic syntax specifications may require further adaption
  2917 (e.g. Cube/Cube.thy).
  2918 
  2919 * Removed obsolete type class "logic", use the top sort {} instead.
  2920 Note that non-logical types should be declared as 'nonterminals'
  2921 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2922 specifications.
  2923 
  2924 * Attributes 'induct' and 'cases': type or set names may now be
  2925 locally fixed variables as well.
  2926 
  2927 * Simplifier: can now control the depth to which conditional rewriting
  2928 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2929 Limit.
  2930 
  2931 * Simplifier: simplification procedures may now take the current
  2932 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2933 interface), which is very useful for calling the Simplifier
  2934 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2935 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2936 low-level mk_simproc no longer applies Logic.varify internally, to
  2937 allow for use in a context of fixed variables.
  2938 
  2939 * thin_tac now works even if the assumption being deleted contains !!
  2940 or ==>.  More generally, erule now works even if the major premise of
  2941 the elimination rule contains !! or ==>.
  2942 
  2943 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2944 
  2945 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2946 from Pure, which contains all common declarations already.  Both
  2947 theories are defined via plain Isabelle/Isar .thy files.
  2948 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2949 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2950 use isatool fixcpure to adapt your theory and ML sources.
  2951 
  2952 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2953 selections of theorems in named facts via index ranges.
  2954 
  2955 * 'print_theorems': in theory mode, really print the difference
  2956 wrt. the last state (works for interactive theory development only),
  2957 in proof mode print all local facts (cf. 'print_facts');
  2958 
  2959 * 'hide': option '(open)' hides only base names.
  2960 
  2961 * More efficient treatment of intermediate checkpoints in interactive
  2962 theory development.
  2963 
  2964 * Code generator is now invoked via code_module (incremental code
  2965 generation) and code_library (modular code generation, ML structures
  2966 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2967 must be quoted when used as identifiers.
  2968 
  2969 * New 'value' command for reading, evaluating and printing terms using
  2970 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2971 quoted when used as identifier.
  2972 
  2973 
  2974 *** Locales ***
  2975 
  2976 * New commands for the interpretation of locale expressions in
  2977 theories (1), locales (2) and proof contexts (3).  These generate
  2978 proof obligations from the expression specification.  After the
  2979 obligations have been discharged, theorems of the expression are added
  2980 to the theory, target locale or proof context.  The synopsis of the
  2981 commands is a follows:
  2982 
  2983   (1) interpretation expr inst
  2984   (2) interpretation target < expr
  2985   (3) interpret expr inst
  2986 
  2987 Interpretation in theories and proof contexts require a parameter
  2988 instantiation of terms from the current context.  This is applied to
  2989 specifications and theorems of the interpreted expression.
  2990 Interpretation in locales only permits parameter renaming through the
  2991 locale expression.  Interpretation is smart in that interpretations
  2992 that are active already do not occur in proof obligations, neither are
  2993 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2994 inspect active interpretations of a particular locale.  For details,
  2995 see the Isar Reference manual.  Examples can be found in
  2996 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2997 
  2998 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2999 'interpret' instead.
  3000 
  3001 * New context element 'constrains' for adding type constraints to
  3002 parameters.
  3003 
  3004 * Context expressions: renaming of parameters with syntax
  3005 redeclaration.
  3006 
  3007 * Locale declaration: 'includes' disallowed.
  3008 
  3009 * Proper static binding of attribute syntax -- i.e. types / terms /
  3010 facts mentioned as arguments are always those of the locale definition
  3011 context, independently of the context of later invocations.  Moreover,
  3012 locale operations (renaming and type / term instantiation) are applied
  3013 to attribute arguments as expected.
  3014 
  3015 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  3016 actual attributes; rare situations may require Attrib.attribute to
  3017 embed those attributes into Attrib.src that lack concrete syntax.
  3018 Attribute implementations need to cooperate properly with the static
  3019 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  3020 Attrib.XXX_thm etc. already do the right thing without further
  3021 intervention.  Only unusual applications -- such as "where" or "of"
  3022 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  3023 on the context and the facts involved -- may have to assign parsed
  3024 values to argument tokens explicitly.
  3025 
  3026 * Changed parameter management in theorem generation for long goal
  3027 statements with 'includes'.  INCOMPATIBILITY: produces a different
  3028 theorem statement in rare situations.
  3029 
  3030 * Locale inspection command 'print_locale' omits notes elements.  Use
  3031 'print_locale!' to have them included in the output.
  3032 
  3033 
  3034 *** Provers ***
  3035 
  3036 * Provers/hypsubst.ML: improved version of the subst method, for
  3037 single-step rewriting: it now works in bound variable contexts. New is
  3038 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  3039 rewrite a different subterm than the original subst method, which is
  3040 still available as 'simplesubst'.
  3041 
  3042 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  3043 and quasi orders.
  3044 
  3045 * Provers/trancl.ML: new transitivity reasoner for transitive and
  3046 reflexive-transitive closure of relations.
  3047 
  3048 * Provers/blast.ML: new reference depth_limit to make blast's depth
  3049 limit (previously hard-coded with a value of 20) user-definable.
  3050 
  3051 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  3052 is peformed already.  Object-logics merely need to finish their
  3053 initial simpset configuration as before.  INCOMPATIBILITY.
  3054 
  3055 
  3056 *** HOL ***
  3057 
  3058 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3059 
  3060   syntax (epsilon)
  3061     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3062 
  3063 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3064 and x-symbol; use option '-m epsilon' to get it actually printed.
  3065 Moreover, the mathematically important symbolic identifier \<epsilon>
  3066 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3067 
  3068 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3069 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3070 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3071 support corresponding Isar calculations.
  3072 
  3073 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3074 instead of ":".
  3075 
  3076 * theory SetInterval: changed the syntax for open intervals:
  3077 
  3078   Old       New
  3079   {..n(}    {..<n}
  3080   {)n..}    {n<..}
  3081   {m..n(}   {m..<n}
  3082   {)m..n}   {m<..n}
  3083   {)m..n(}  {m<..<n}
  3084 
  3085 The old syntax is still supported but will disappear in the next
  3086 release.  For conversion use the following Emacs search and replace
  3087 patterns (these are not perfect but work quite well):
  3088 
  3089   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3090   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3091 
  3092 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3093 equalities in commutative rings; method 'algebra' provides a generic
  3094 interface.
  3095 
  3096 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3097 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3098 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3099 be a tuple pattern.
  3100 
  3101 Some new syntax forms are available:
  3102 
  3103   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3104   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3105   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3106   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3107 
  3108 The latter form "\<Sum>x < k. e" used to be based on a separate
  3109 function "Summation", which has been discontinued.
  3110 
  3111 * theory Finite_Set: in structured induction proofs, the insert case
  3112 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3113 (insert F x)'.
  3114 
  3115 * The 'refute' command has been extended to support a much larger
  3116 fragment of HOL, including axiomatic type classes, constdefs and
  3117 typedefs, inductive datatypes and recursion.
  3118 
  3119 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3120 Requires zChaff with proof generation to be installed.  See
  3121 HOL/ex/SAT_Examples.thy for examples.
  3122 
  3123 * Datatype induction via method 'induct' now preserves the name of the
  3124 induction variable. For example, when proving P(xs::'a list) by
  3125 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3126 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3127 in unstructured proof scripts.
  3128 
  3129 * Reworked implementation of records.  Improved scalability for
  3130 records with many fields, avoiding performance problems for type
  3131 inference. Records are no longer composed of nested field types, but
  3132 of nested extension types. Therefore the record type only grows linear
  3133 in the number of extensions and not in the number of fields.  The
  3134 top-level (users) view on records is preserved.  Potential
  3135 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3136 old record representation. The type generated for a record is called
  3137 <record_name>_ext_type.
  3138 
  3139 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3140 proofs triggered by a record definition or a simproc (if
  3141 quick_and_dirty is enabled).  Definitions of large records can take
  3142 quite long.
  3143 
  3144 New simproc record_upd_simproc for simplification of multiple record
  3145 updates enabled by default.  Moreover, trivial updates are also
  3146 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3147 occasionally, since simplification is more powerful by default.
  3148 
  3149 * typedef: proper support for polymorphic sets, which contain extra
  3150 type-variables in the term.
  3151 
  3152 * Simplifier: automatically reasons about transitivity chains
  3153 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3154 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3155 old proofs break occasionally as simplification may now solve more
  3156 goals than previously.
  3157 
  3158 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3159 present.  Works for all partial orders (class "order"), in particular
  3160 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3161 just like y <= x.
  3162 
  3163 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3164 bound variable or a constant then the let is unfolded.  Otherwise
  3165 first a is simplified to b, and then f b is simplified to g. If
  3166 possible we abstract b from g arriving at "let x = b in h x",
  3167 otherwise we unfold the let and arrive at g.  The simproc can be
  3168 enabled/disabled by the reference use_let_simproc.  Potential
  3169 INCOMPATIBILITY since simplification is more powerful by default.
  3170 
  3171 * Classical reasoning: the meson method now accepts theorems as arguments.
  3172 
  3173 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3174 jobs to provide advice on the provability of subgoals.
  3175 
  3176 * Theory OrderedGroup and Ring_and_Field: various additions and
  3177 improvements to faciliate calculations involving equalities and
  3178 inequalities.
  3179 
  3180 The following theorems have been eliminated or modified
  3181 (INCOMPATIBILITY):
  3182 
  3183   abs_eq             now named abs_of_nonneg
  3184   abs_of_ge_0        now named abs_of_nonneg
  3185   abs_minus_eq       now named abs_of_nonpos
  3186   imp_abs_id         now named abs_of_nonneg
  3187   imp_abs_neg_id     now named abs_of_nonpos
  3188   mult_pos           now named mult_pos_pos
  3189   mult_pos_le        now named mult_nonneg_nonneg
  3190   mult_pos_neg_le    now named mult_nonneg_nonpos
  3191   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3192   mult_neg           now named mult_neg_neg
  3193   mult_neg_le        now named mult_nonpos_nonpos
  3194 
  3195 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3196      
  3197      zero_le_square
  3198      not_square_less_zero 
  3199 
  3200   The following lemmas have been deleted from Real/RealPow:
  3201   
  3202      realpow_zero_zero
  3203      realpow_two
  3204      realpow_less
  3205      zero_le_power
  3206      realpow_two_le
  3207      abs_realpow_two
  3208      realpow_two_abs     
  3209 
  3210 * Theory Parity: added rules for simplifying exponents.
  3211 
  3212 * Theory List:
  3213 
  3214 The following theorems have been eliminated or modified
  3215 (INCOMPATIBILITY):
  3216 
  3217   list_all_Nil       now named list_all.simps(1)
  3218   list_all_Cons      now named list_all.simps(2)
  3219   list_all_conv      now named list_all_iff
  3220   set_mem_eq         now named mem_iff
  3221 
  3222 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3223 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3224 
  3225 
  3226 *** HOL-Complex ***
  3227 
  3228 * Theory RealDef: better support for embedding natural numbers and
  3229 integers in the reals.
  3230 
  3231 The following theorems have been eliminated or modified
  3232 (INCOMPATIBILITY):
  3233 
  3234   exp_ge_add_one_self  now requires no hypotheses
  3235   real_of_int_add      reversed direction of equality (use [symmetric])
  3236   real_of_int_minus    reversed direction of equality (use [symmetric])
  3237   real_of_int_diff     reversed direction of equality (use [symmetric])
  3238   real_of_int_mult     reversed direction of equality (use [symmetric])
  3239 
  3240 * Theory RComplete: expanded support for floor and ceiling functions.
  3241 
  3242 * Theory Ln is new, with properties of the natural logarithm
  3243 
  3244 * Hyperreal: There is a new type constructor "star" for making
  3245 nonstandard types.  The old type names are now type synonyms:
  3246 
  3247   hypreal = real star
  3248   hypnat = nat star
  3249   hcomplex = complex star
  3250 
  3251 * Hyperreal: Many groups of similarly-defined constants have been
  3252 replaced by polymorphic versions (INCOMPATIBILITY):
  3253 
  3254   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3255 
  3256   starset      <-- starsetNat, starsetC
  3257   *s*          <-- *sNat*, *sc*
  3258   starset_n    <-- starsetNat_n, starsetC_n
  3259   *sn*         <-- *sNatn*, *scn*
  3260   InternalSets <-- InternalNatSets, InternalCSets
  3261 
  3262   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3263   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3264   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3265   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3266   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3267 
  3268 * Hyperreal: Many type-specific theorems have been removed in favor of
  3269 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3270 
  3271   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3272   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3273   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3274   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3275   right_minus <-- hypreal_add_minus
  3276   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3277   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3278   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3279   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3280   mult_1_right <-- hcomplex_mult_one_right
  3281   mult_zero_left <-- hcomplex_mult_zero_left
  3282   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3283   right_distrib <-- hypnat_add_mult_distrib2
  3284   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3285   right_inverse <-- hypreal_mult_inverse
  3286   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3287   order_refl <-- {hypreal,hypnat}_le_refl
  3288   order_trans <-- {hypreal,hypnat}_le_trans
  3289   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3290   order_less_le <-- {hypreal,hypnat}_less_le
  3291   linorder_linear <-- {hypreal,hypnat}_le_linear
  3292   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3293   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3294   add_nonneg_nonneg <-- hypreal_le_add_order
  3295 
  3296 * Hyperreal: Separate theorems having to do with type-specific
  3297 versions of constants have been merged into theorems that apply to the
  3298 new polymorphic constants (INCOMPATIBILITY):
  3299 
  3300   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3301   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3302   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3303   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3304   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3305   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3306   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3307   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3308   STAR_diff <-- {STAR,STARC}_diff
  3309   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3310     STARC_hcomplex_of_complex}_image_subset
  3311   starset_n_Un <-- starset{Nat,C}_n_Un
  3312   starset_n_Int <-- starset{Nat,C}_n_Int
  3313   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3314   starset_n_diff <-- starset{Nat,C}_n_diff
  3315   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3316   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3317   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3318   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3319   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3320   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3321   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3322   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3323   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3324   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3325   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3326   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3327   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3328   starfun_diff <-- starfun{C,RC,CR}_diff
  3329   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3330   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3331   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3332   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3333   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3334   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3335   starfun_Id <-- starfunC_Id
  3336   starfun_approx <-- starfun{Nat,CR}_approx
  3337   starfun_capprox <-- starfun{C,RC}_capprox
  3338   starfun_abs <-- starfunNat_rabs
  3339   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3340   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3341   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3342   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3343   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3344   starfun_add_approx <-- starfunCR_add_approx
  3345   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3346   starfun_divide <-- starfun{C,CR,RC}_divide
  3347   starfun_n <-- starfun{Nat,C}_n
  3348   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3349   starfun_n_add <-- starfun{Nat,C}_n_add
  3350   starfun_n_add_minus <-- starfunNat_n_add_minus
  3351   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3352   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3353   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3354 
  3355   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3356   star_n_minus <-- {hypreal,hcomplex}_minus
  3357   star_n_diff <-- {hypreal,hcomplex}_diff
  3358   star_n_mult <-- {hypreal,hcomplex}_mult
  3359   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3360   star_n_le <-- {hypreal,hypnat}_le
  3361   star_n_less <-- {hypreal,hypnat}_less
  3362   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3363   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3364   star_n_abs <-- hypreal_hrabs
  3365   star_n_divide <-- hcomplex_divide
  3366 
  3367   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3368   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3369   star_of_diff <-- hypreal_of_real_diff
  3370   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3371   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3372   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3373   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3374   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3375   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3376   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3377   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3378   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3379   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3380   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3381   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3382   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3383   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3384   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3385   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3386   star_of_power <-- hypreal_of_real_power
  3387   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3388 
  3389 * Hyperreal: new method "transfer" that implements the transfer
  3390 principle of nonstandard analysis. With a subgoal that mentions
  3391 nonstandard types like "'a star", the command "apply transfer"
  3392 replaces it with an equivalent one that mentions only standard types.
  3393 To be successful, all free variables must have standard types; non-
  3394 standard variables must have explicit universal quantifiers.
  3395 
  3396 * Hyperreal: A theory of Taylor series.
  3397 
  3398 
  3399 *** HOLCF ***
  3400 
  3401 * Discontinued special version of 'constdefs' (which used to support
  3402 continuous functions) in favor of the general Pure one with full
  3403 type-inference.
  3404 
  3405 * New simplification procedure for solving continuity conditions; it
  3406 is much faster on terms with many nested lambda abstractions (cubic
  3407 instead of exponential time).
  3408 
  3409 * New syntax for domain package: selector names are now optional.
  3410 Parentheses should be omitted unless argument is lazy, for example:
  3411 
  3412   domain 'a stream = cons "'a" (lazy "'a stream")
  3413 
  3414 * New command 'fixrec' for defining recursive functions with pattern
  3415 matching; defining multiple functions with mutual recursion is also
  3416 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3417 sinr, or any data constructor defined by the domain package. The given
  3418 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3419 syntax and examples.
  3420 
  3421 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3422 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3423 but the proof obligation additionally includes an admissibility
  3424 requirement. The packages generate instances of class cpo or pcpo,
  3425 with continuity and strictness theorems for Rep and Abs.
  3426 
  3427 * HOLCF: Many theorems have been renamed according to a more standard naming
  3428 scheme (INCOMPATIBILITY):
  3429 
  3430   foo_inject:  "foo$x = foo$y ==> x = y"
  3431   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3432   foo_less:    "(foo$x << foo$y) = (x << y)"
  3433   foo_strict:  "foo$UU = UU"
  3434   foo_defined: "... ==> foo$x ~= UU"
  3435   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3436 
  3437 
  3438 *** ZF ***
  3439 
  3440 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3441 including the First Isomorphism Theorem (on quotienting by the kernel
  3442 of a homomorphism).
  3443 
  3444 * ZF/Simplifier: install second copy of type solver that actually
  3445 makes use of TC rules declared to Isar proof contexts (or locales);
  3446 the old version is still required for ML proof scripts.
  3447 
  3448 
  3449 *** Cube ***
  3450 
  3451 * Converted to Isar theory format; use locales instead of axiomatic
  3452 theories.
  3453 
  3454 
  3455 *** ML ***
  3456 
  3457 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3458 for ||>, ||>>, |>>,
  3459 
  3460 * Pure/library.ML no longer defines its own option datatype, but uses
  3461 that of the SML basis, which has constructors NONE and SOME instead of
  3462 None and Some, as well as exception Option.Option instead of OPTION.
  3463 The functions the, if_none, is_some, is_none have been adapted
  3464 accordingly, while Option.map replaces apsome.
  3465 
  3466 * Pure/library.ML: the exception LIST has been given up in favour of
  3467 the standard exceptions Empty and Subscript, as well as
  3468 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3469 superceded by the standard hd and tl functions etc.
  3470 
  3471 A number of basic list functions are no longer exported to the ML
  3472 toplevel, as they are variants of predefined functions.  The following
  3473 suggests how one can translate existing code:
  3474 
  3475     rev_append xs ys = List.revAppend (xs, ys)
  3476     nth_elem (i, xs) = List.nth (xs, i)
  3477     last_elem xs = List.last xs
  3478     flat xss = List.concat xss
  3479     seq fs = List.app fs
  3480     partition P xs = List.partition P xs
  3481     mapfilter f xs = List.mapPartial f xs
  3482 
  3483 * Pure/library.ML: several combinators for linear functional
  3484 transformations, notably reverse application and composition:
  3485 
  3486   x |> f                f #> g
  3487   (x, y) |-> f          f #-> g
  3488 
  3489 * Pure/library.ML: introduced/changed precedence of infix operators:
  3490 
  3491   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3492   infix 2 ?;
  3493   infix 3 o oo ooo oooo;
  3494   infix 4 ~~ upto downto;
  3495 
  3496 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3497 infix operators.
  3498 
  3499 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3500 fold_map support linear functional transformations and nesting.  For
  3501 example:
  3502 
  3503   fold f [x1, ..., xN] y =
  3504     y |> f x1 |> ... |> f xN
  3505 
  3506   (fold o fold) f [xs1, ..., xsN] y =
  3507     y |> fold f xs1 |> ... |> fold f xsN
  3508 
  3509   fold f [x1, ..., xN] =
  3510     f x1 #> ... #> f xN
  3511 
  3512   (fold o fold) f [xs1, ..., xsN] =
  3513     fold f xs1 #> ... #> fold f xsN
  3514 
  3515 * Pure/library.ML: the following selectors on type 'a option are
  3516 available:
  3517 
  3518   the:               'a option -> 'a  (*partial*)
  3519   these:             'a option -> 'a  where 'a = 'b list
  3520   the_default: 'a -> 'a option -> 'a
  3521   the_list:          'a option -> 'a list
  3522 
  3523 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3524 basic operations for association lists, following natural argument
  3525 order; moreover the explicit equality predicate passed here avoids
  3526 potentially expensive polymorphic runtime equality checks.
  3527 The old functions may be expressed as follows:
  3528 
  3529   assoc = uncurry (AList.lookup (op =))
  3530   assocs = these oo AList.lookup (op =)
  3531   overwrite = uncurry (AList.update (op =)) o swap
  3532 
  3533 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3534 
  3535   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3536   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3537 
  3538 replacing make_keylist and keyfilter (occassionally used)
  3539 Naive rewrites:
  3540 
  3541   make_keylist = AList.make
  3542   keyfilter = AList.find (op =)
  3543 
  3544 * eq_fst and eq_snd now take explicit equality parameter, thus
  3545   avoiding eqtypes. Naive rewrites:
  3546 
  3547     eq_fst = eq_fst (op =)
  3548     eq_snd = eq_snd (op =)
  3549 
  3550 * Removed deprecated apl and apr (rarely used).
  3551   Naive rewrites:
  3552 
  3553     apl (n, op) =>>= curry op n
  3554     apr (op, m) =>>= fn n => op (n, m)
  3555 
  3556 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3557 provides a reasonably efficient light-weight implementation of sets as
  3558 lists.
  3559 
  3560 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3561 few new operations; existing lookup and update are now curried to
  3562 follow natural argument order (for use with fold etc.);
  3563 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3564 
  3565 * Pure/General: output via the Isabelle channels of
  3566 writeln/warning/error etc. is now passed through Output.output, with a
  3567 hook for arbitrary transformations depending on the print_mode
  3568 (cf. Output.add_mode -- the first active mode that provides a output
  3569 function wins).  Already formatted output may be embedded into further
  3570 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3571 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3572 accommodate easy composition of diagnostic messages etc.  Programmers
  3573 rarely need to care about Output.output or Output.raw at all, with
  3574 some notable exceptions: Output.output is required when bypassing the
  3575 standard channels (writeln etc.), or in token translations to produce
  3576 properly formatted results; Output.raw is required when capturing
  3577 already output material that will eventually be presented to the user
  3578 a second time.  For the default print mode, both Output.output and
  3579 Output.raw have no effect.
  3580 
  3581 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3582 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3583 cumulative results are displayed at the end of a batch session.
  3584 
  3585 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3586 replaced by File.platform_path and File.shell_path (with appropriate
  3587 hooks).  This provides a clean interface for unusual systems where the
  3588 internal and external process view of file names are different.
  3589 
  3590 * Pure: more efficient orders for basic syntactic entities: added
  3591 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3592 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3593 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3594 orders now -- potential INCOMPATIBILITY for code that depends on a
  3595 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3596 Library.sort_strings on result).
  3597 
  3598 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3599 fold_types traverse types/terms from left to right, observing natural
  3600 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3601 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3602 
  3603 * Pure: name spaces have been refined, with significant changes of the
  3604 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3605 to extern(_table).  The plain name entry path is superceded by a
  3606 general 'naming' context, which also includes the 'policy' to produce
  3607 a fully qualified name and external accesses of a fully qualified
  3608 name; NameSpace.extend is superceded by context dependent
  3609 Sign.declare_name.  Several theory and proof context operations modify
  3610 the naming context.  Especially note Theory.restore_naming and
  3611 ProofContext.restore_naming to get back to a sane state; note that
  3612 Theory.add_path is no longer sufficient to recover from
  3613 Theory.absolute_path in particular.
  3614 
  3615 * Pure: new flags short_names (default false) and unique_names
  3616 (default true) for controlling output of qualified names.  If
  3617 short_names is set, names are printed unqualified.  If unique_names is
  3618 reset, the name prefix is reduced to the minimum required to achieve
  3619 the original result when interning again, even if there is an overlap
  3620 with earlier declarations.
  3621 
  3622 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3623 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3624 (useful for printing error messages).  INCOMPATIBILITY.
  3625 
  3626 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3627 Theory.theory are now identified, referring to the universal
  3628 Context.theory (see Pure/context.ML).  Actual signature and theory
  3629 content is managed as theory data.  The old code and interfaces were
  3630 spread over many files and structures; the new arrangement introduces
  3631 considerable INCOMPATIBILITY to gain more clarity:
  3632 
  3633   Context -- theory management operations (name, identity, inclusion,
  3634     parents, ancestors, merge, etc.), plus generic theory data;
  3635 
  3636   Sign -- logical signature and syntax operations (declaring consts,
  3637     types, etc.), plus certify/read for common entities;
  3638 
  3639   Theory -- logical theory operations (stating axioms, definitions,
  3640     oracles), plus a copy of logical signature operations (consts,
  3641     types, etc.); also a few basic management operations (Theory.copy,
  3642     Theory.merge, etc.)
  3643 
  3644 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3645 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3646 for convenience -- they merely return the theory.
  3647 
  3648 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3649 
  3650 * Pure: the Isar proof context type is already defined early in Pure
  3651 as Context.proof (note that ProofContext.context and Proof.context are
  3652 aliases, where the latter is the preferred name).  This enables other
  3653 Isabelle components to refer to that type even before Isar is present.
  3654 
  3655 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3656 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3657 any of these kinds.  For example, Sign.intern typeK is now
  3658 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3659 Theory.hide_types.  Also note that former
  3660 Theory.hide_classes/types/consts are now
  3661 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3662 internalize their arguments!  INCOMPATIBILITY.
  3663 
  3664 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3665 datatype thmref (with constructors Name and NameSelection) instead of
  3666 plain string -- INCOMPATIBILITY;
  3667 
  3668 * Pure: cases produced by proof methods specify options, where NONE
  3669 means to remove case bindings -- INCOMPATIBILITY in
  3670 (RAW_)METHOD_CASES.
  3671 
  3672 * Pure: the following operations retrieve axioms or theorems from a
  3673 theory node or theory hierarchy, respectively:
  3674 
  3675   Theory.axioms_of: theory -> (string * term) list
  3676   Theory.all_axioms_of: theory -> (string * term) list
  3677   PureThy.thms_of: theory -> (string * thm) list
  3678   PureThy.all_thms_of: theory -> (string * thm) list
  3679 
  3680 * Pure: print_tac now outputs the goal through the trace channel.
  3681 
  3682 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3683 Reference Toplevel.debug (default false) controls detailed printing
  3684 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3685 controls execution profiling -- set to 1 for time and 2 for space
  3686 (both increase the runtime).
  3687 
  3688 * Isar session: The initial use of ROOT.ML is now always timed,
  3689 i.e. the log will show the actual process times, in contrast to the
  3690 elapsed wall-clock time that the outer shell wrapper produces.
  3691 
  3692 * Simplifier: improved handling of bound variables (nameless
  3693 representation, avoid allocating new strings).  Simprocs that invoke
  3694 the Simplifier recursively should use Simplifier.inherit_bounds to
  3695 avoid local name clashes.  Failure to do so produces warnings
  3696 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3697 for further details.
  3698 
  3699 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3700 bindings for all theorems stored within a given theory; this may help
  3701 in porting non-Isar theories to Isar ones, while keeping ML proof
  3702 scripts for the time being.
  3703 
  3704 * ML operator HTML.with_charset specifies the charset begin used for
  3705 generated HTML files.  For example:
  3706 
  3707   HTML.with_charset "utf-8" use_thy "Hebrew";
  3708   HTML.with_charset "utf-8" use_thy "Chinese";
  3709 
  3710 
  3711 *** System ***
  3712 
  3713 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3714 isabelle, isatool etc.).
  3715 
  3716 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3717 isatool doc, isatool mkdir, display_drafts etc.).
  3718 
  3719 * isatool usedir: option -f allows specification of the ML file to be
  3720 used by Isabelle; default is ROOT.ML.
  3721 
  3722 * New isatool version outputs the version identifier of the Isabelle
  3723 distribution being used.
  3724 
  3725 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3726 (containing Boolean satisfiability problems) into Isabelle/HOL
  3727 theories.
  3728 
  3729 
  3730 
  3731 New in Isabelle2004 (April 2004)
  3732 --------------------------------
  3733 
  3734 *** General ***
  3735 
  3736 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3737   Replaces linorder.ML.
  3738 
  3739 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3740   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3741   (\<a>...\<z>), are now considered normal letters, and can therefore
  3742   be used anywhere where an ASCII letter (a...zA...Z) has until
  3743   now. COMPATIBILITY: This obviously changes the parsing of some
  3744   terms, especially where a symbol has been used as a binder, say
  3745   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3746   as an identifier.  Fix it by inserting a space around former
  3747   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3748   existing theory and ML files.
  3749 
  3750 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3751 
  3752 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3753   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3754   a normal (but invisible) letter. For multiple letter subscripts repeat
  3755   \<^isub> like this: x\<^isub>1\<^isub>2.
  3756 
  3757 * Pure: There are now sub-/superscripts that can span more than one
  3758   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3759   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3760   superscript. The new control characters are not identifier parts.
  3761 
  3762 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3763   content of "..." to the latex file instead of \isacntrl... . The "..."
  3764   may consist of any printable characters excluding the end bracket >.
  3765 
  3766 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3767   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3768   declare constants "final", which prevents their being given a definition
  3769   later.  It is useful for constants whose behaviour is fixed axiomatically
  3770   rather than definitionally, such as the meta-logic connectives.
  3771 
  3772 * Pure: 'instance' now handles general arities with general sorts
  3773   (i.e. intersections of classes),
  3774 
  3775 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3776   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3777   It can be changed to alter the colors/layout of generated pages.
  3778 
  3779 
  3780 *** Isar ***
  3781 
  3782 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3783   cut_tac, subgoal_tac and thin_tac:
  3784   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3785     locales are no longer forced to write Isar proof scripts.
  3786     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3787     emulations.
  3788   - INCOMPATIBILITY: names of variables to be instantiated may no
  3789     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3790     This is consistent with the instantiation attribute "where".
  3791 
  3792 * Attributes "where" and "of":
  3793   - Now take type variables of instantiated theorem into account when reading
  3794     the instantiation string.  This fixes a bug that caused instantiated
  3795     theorems to have too special types in some circumstances.
  3796   - "where" permits explicit instantiations of type variables.
  3797 
  3798 * Calculation commands "moreover" and "also" no longer interfere with
  3799   current facts ("this"), admitting arbitrary combinations with "then"
  3800   and derived forms.
  3801 
  3802 * Locales:
  3803   - Goal statements involving the context element "includes" no longer
  3804     generate theorems with internal delta predicates (those ending on
  3805     "_axioms") in the premise.
  3806     Resolve particular premise with <locale>.intro to obtain old form.
  3807   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3808     specification and "includes" elements in goal statement.
  3809   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3810     [intro?] and [elim?] (respectively) by default.
  3811   - Experimental command for instantiation of locales in proof contexts:
  3812         instantiate <label>[<attrs>]: <loc>
  3813     Instantiates locale <loc> and adds all its theorems to the current context
  3814     taking into account their attributes.  Label and attrs are optional
  3815     modifiers, like in theorem declarations.  If present, names of
  3816     instantiated theorems are qualified with <label>, and the attributes
  3817     <attrs> are applied after any attributes these theorems might have already.
  3818       If the locale has assumptions, a chained fact of the form
  3819     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3820     are derived.  The command does not support old-style locales declared
  3821     with "locale (open)".
  3822       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3823 
  3824 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3825   (Isar) contexts.
  3826 
  3827 
  3828 *** HOL ***
  3829 
  3830 * Proof import: new image HOL4 contains the imported library from
  3831   the HOL4 system with about 2500 theorems. It is imported by
  3832   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3833   can be used like any other Isabelle image.  See
  3834   HOL/Import/HOL/README for more information.
  3835 
  3836 * Simplifier:
  3837   - Much improved handling of linear and partial orders.
  3838     Reasoners for linear and partial orders are set up for type classes
  3839     "linorder" and "order" respectively, and are added to the default simpset
  3840     as solvers.  This means that the simplifier can build transitivity chains
  3841     to solve goals from the assumptions.
  3842   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3843     of blast or auto after simplification become unnecessary because the goal
  3844     is solved by simplification already.
  3845 
  3846 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3847     all proved in axiomatic type classes for semirings, rings and fields.
  3848 
  3849 * Numerics:
  3850   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3851     now formalized using the Ring_and_Field theory mentioned above.
  3852   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3853     than before, because now they are set up once in a generic manner.
  3854   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3855     Look for the general versions in Ring_and_Field (and Power if they concern
  3856     exponentiation).
  3857 
  3858 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3859 
  3860 * Records:
  3861   - Record types are now by default printed with their type abbreviation
  3862     instead of the list of all field types. This can be configured via
  3863     the reference "print_record_type_abbr".
  3864   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3865     (not enabled by default).
  3866   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3867     EX x. x = sel r to True (not enabled by default).
  3868   - Tactic "record_split_simp_tac" to split and simplify records added.
  3869 
  3870 * 'specification' command added, allowing for definition by
  3871   specification.  There is also an 'ax_specification' command that
  3872   introduces the new constants axiomatically.
  3873 
  3874 * arith(_tac) is now able to generate counterexamples for reals as well.
  3875 
  3876 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3877 
  3878 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3879   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3880 
  3881 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3882   matrix theory to linear programming.
  3883 
  3884 * Unions and Intersections:
  3885   The latex output syntax of UN and INT has been changed
  3886   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3887   i.e. the index formulae has become a subscript.
  3888   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3889 
  3890 * Unions and Intersections over Intervals:
  3891   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3892   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3893   like in normal math, and corresponding versions for < and for intersection.
  3894 
  3895 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3896   lexicographic dictonary ordering has been added as "lexord".
  3897 
  3898 * ML: the legacy theory structures Int and List have been removed. They had
  3899   conflicted with ML Basis Library structures having the same names.
  3900 
  3901 * 'refute' command added to search for (finite) countermodels.  Only works
  3902   for a fragment of HOL.  The installation of an external SAT solver is
  3903   highly recommended.  See "HOL/Refute.thy" for details.
  3904 
  3905 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3906   formulae under an assignment of free variables to random values.
  3907   In contrast to 'refute', it can deal with inductive datatypes,
  3908   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3909   for examples.
  3910 
  3911 
  3912 *** HOLCF ***
  3913 
  3914 * Streams now come with concatenation and are part of the HOLCF image
  3915 
  3916 
  3917 
  3918 New in Isabelle2003 (May 2003)
  3919 ------------------------------
  3920 
  3921 *** General ***
  3922 
  3923 * Provers/simplifier:
  3924 
  3925   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3926     Assumptions are now subject to complete mutual simplification,
  3927     not just from left to right. The simplifier now preserves
  3928     the order of assumptions.
  3929 
  3930     Potential INCOMPATIBILITY:
  3931 
  3932     -- simp sometimes diverges where the old version did
  3933        not, e.g. invoking simp on the goal
  3934 
  3935         [| P (f x); y = x; f x = f y |] ==> Q
  3936 
  3937        now gives rise to the infinite reduction sequence
  3938 
  3939         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3940 
  3941        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3942        kind of problem.
  3943 
  3944     -- Tactics combining classical reasoner and simplification (such as auto)
  3945        are also affected by this change, because many of them rely on
  3946        simp. They may sometimes diverge as well or yield a different numbers
  3947        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3948        in case of problems. Sometimes subsequent calls to the classical
  3949        reasoner will fail because a preceeding call to the simplifier too
  3950        eagerly simplified the goal, e.g. deleted redundant premises.
  3951 
  3952   - The simplifier trace now shows the names of the applied rewrite rules
  3953 
  3954   - You can limit the number of recursive invocations of the simplifier
  3955     during conditional rewriting (where the simplifie tries to solve the
  3956     conditions before applying the rewrite rule):
  3957     ML "simp_depth_limit := n"
  3958     where n is an integer. Thus you can force termination where previously
  3959     the simplifier would diverge.
  3960 
  3961   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3962 
  3963   - No longer aborts on failed congruence proof.  Instead, the
  3964     congruence is ignored.
  3965 
  3966 * Pure: New generic framework for extracting programs from constructive
  3967   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3968   as HOL/Extraction for some case studies.
  3969 
  3970 * Pure: The main goal of the proof state is no longer shown by default, only
  3971 the subgoals. This behaviour is controlled by a new flag.
  3972    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3973 (ML: Proof.show_main_goal).
  3974 
  3975 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3976 rules whose conclusion matches subgoal 1:
  3977       PG menu: Isabelle/Isar -> Show me -> matching rules
  3978 The rules are ordered by how closely they match the subgoal.
  3979 In particular, rules that solve a subgoal outright are displayed first
  3980 (or rather last, the way they are printed).
  3981 (ML: ProofGeneral.print_intros())
  3982 
  3983 * Pure: New flag trace_unify_fail causes unification to print
  3984 diagnostic information (PG: in trace buffer) when it fails. This is
  3985 useful for figuring out why single step proofs like rule, erule or
  3986 assumption failed.
  3987 
  3988 * Pure: Locale specifications now produce predicate definitions
  3989 according to the body of text (covering assumptions modulo local
  3990 definitions); predicate "loc_axioms" covers newly introduced text,
  3991 while "loc" is cumulative wrt. all included locale expressions; the
  3992 latter view is presented only on export into the global theory
  3993 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3994 on the old view without predicates;
  3995 
  3996 * Pure: predefined locales "var" and "struct" are useful for sharing
  3997 parameters (as in CASL, for example); just specify something like
  3998 ``var x + var y + struct M'' as import;
  3999 
  4000 * Pure: improved thms_containing: proper indexing of facts instead of
  4001 raw theorems; check validity of results wrt. current name space;
  4002 include local facts of proof configuration (also covers active
  4003 locales), cover fixed variables in index; may use "_" in term
  4004 specification; an optional limit for the number of printed facts may
  4005 be given (the default is 40);
  4006 
  4007 * Pure: disallow duplicate fact bindings within new-style theory files
  4008 (batch-mode only);
  4009 
  4010 * Provers: improved induct method: assumptions introduced by case
  4011 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  4012 the goal statement); "foo" still refers to all facts collectively;
  4013 
  4014 * Provers: the function blast.overloaded has been removed: all constants
  4015 are regarded as potentially overloaded, which improves robustness in exchange
  4016 for slight decrease in efficiency;
  4017 
  4018 * Provers/linorder: New generic prover for transitivity reasoning over
  4019 linear orders.  Note: this prover is not efficient!
  4020 
  4021 * Isar: preview of problems to finish 'show' now produce an error
  4022 rather than just a warning (in interactive mode);
  4023 
  4024 
  4025 *** HOL ***
  4026 
  4027 * arith(_tac)
  4028 
  4029  - Produces a counter example if it cannot prove a goal.
  4030    Note that the counter example may be spurious if the goal is not a formula
  4031    of quantifier-free linear arithmetic.
  4032    In ProofGeneral the counter example appears in the trace buffer.
  4033 
  4034  - Knows about div k and mod k where k is a numeral of type nat or int.
  4035 
  4036  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  4037    linear arithmetic fails. This takes account of quantifiers and divisibility.
  4038    Presburger arithmetic can also be called explicitly via presburger(_tac).
  4039 
  4040 * simp's arithmetic capabilities have been enhanced a bit: it now
  4041 takes ~= in premises into account (by performing a case split);
  4042 
  4043 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  4044 are distributed over a sum of terms;
  4045 
  4046 * New tactic "trans_tac" and method "trans" instantiate
  4047 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  4048 "<=", "<" and "=").
  4049 
  4050 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  4051 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  4052 
  4053 * 'typedef' command has new option "open" to suppress the set
  4054 definition;
  4055 
  4056 * functions Min and Max on finite sets have been introduced (theory
  4057 Finite_Set);
  4058 
  4059 * attribute [symmetric] now works for relations as well; it turns
  4060 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4061 
  4062 * induct over a !!-quantified statement (say !!x1..xn):
  4063   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4064 
  4065 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4066 %x. None. Warning: empty_def now refers to the previously hidden definition
  4067 of the empty set.
  4068 
  4069 * Algebra: formalization of classical algebra.  Intended as base for
  4070 any algebraic development in Isabelle.  Currently covers group theory
  4071 (up to Sylow's theorem) and ring theory (Universal Property of
  4072 Univariate Polynomials).  Contributions welcome;
  4073 
  4074 * GroupTheory: deleted, since its material has been moved to Algebra;
  4075 
  4076 * Complex: new directory of the complex numbers with numeric constants,
  4077 nonstandard complex numbers, and some complex analysis, standard and
  4078 nonstandard (Jacques Fleuriot);
  4079 
  4080 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4081 
  4082 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4083 Fleuriot);
  4084 
  4085 * Real/HahnBanach: updated and adapted to locales;
  4086 
  4087 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4088 Gray and Kramer);
  4089 
  4090 * UNITY: added the Meier-Sanders theory of progress sets;
  4091 
  4092 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4093 as abstract algorithms, instantiated to the JVM;
  4094 
  4095 * Bali: Java source language formalization. Type system, operational
  4096 semantics, axiomatic semantics. Supported language features:
  4097 classes, interfaces, objects,virtual methods, static methods,
  4098 static/instance fields, arrays, access modifiers, definite
  4099 assignment, exceptions.
  4100 
  4101 
  4102 *** ZF ***
  4103 
  4104 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4105 universe, etc.);
  4106 
  4107 * Main ZF: virtually all theories converted to new-style format;
  4108 
  4109 
  4110 *** ML ***
  4111 
  4112 * Pure: Tactic.prove provides sane interface for internal proofs;
  4113 omits the infamous "standard" operation, so this is more appropriate
  4114 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4115 
  4116 * Pure: improved error reporting of simprocs;
  4117 
  4118 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4119 up simprocs;
  4120 
  4121 
  4122 *** Document preparation ***
  4123 
  4124 * uses \par instead of \\ for line breaks in theory text. This may
  4125 shift some page breaks in large documents. To get the old behaviour
  4126 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4127 
  4128 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4129 other packages
  4130 
  4131 * \<euro> now needs package babel/greek instead of marvosym (which
  4132 broke \Rightarrow)
  4133 
  4134 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4135 textcomp package)
  4136 
  4137 
  4138 
  4139 New in Isabelle2002 (March 2002)
  4140 --------------------------------
  4141 
  4142 *** Document preparation ***
  4143 
  4144 * greatly simplified document preparation setup, including more
  4145 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4146 instructive isatool mkdir; users should basically be able to get
  4147 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4148 users may run a separate document processing stage manually like this:
  4149 "isatool usedir -D output HOL Test && isatool document Test/output";
  4150 
  4151 * theory dependency graph may now be incorporated into documents;
  4152 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4153 with \includegraphics of LaTeX;
  4154 
  4155 * proper spacing of consecutive markup elements, especially text
  4156 blocks after section headings;
  4157 
  4158 * support bold style (for single symbols only), input syntax is like
  4159 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4160 
  4161 * \<bullet> is now output as bold \cdot by default, which looks much
  4162 better in printed text;
  4163 
  4164 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4165 note that these symbols are currently unavailable in Proof General /
  4166 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4167 
  4168 * isatool latex no longer depends on changed TEXINPUTS, instead
  4169 isatool document copies the Isabelle style files to the target
  4170 location;
  4171 
  4172 
  4173 *** Isar ***
  4174 
  4175 * Pure/Provers: improved proof by cases and induction;
  4176   - 'case' command admits impromptu naming of parameters (such as
  4177     "case (Suc n)");
  4178   - 'induct' method divinates rule instantiation from the inductive
  4179     claim; no longer requires excessive ?P bindings for proper
  4180     instantiation of cases;
  4181   - 'induct' method properly enumerates all possibilities of set/type
  4182     rules; as a consequence facts may be also passed through *type*
  4183     rules without further ado;
  4184   - 'induct' method now derives symbolic cases from the *rulified*
  4185     rule (before it used to rulify cases stemming from the internal
  4186     atomized version); this means that the context of a non-atomic
  4187     statement becomes is included in the hypothesis, avoiding the
  4188     slightly cumbersome show "PROP ?case" form;
  4189   - 'induct' may now use elim-style induction rules without chaining
  4190     facts, using ``missing'' premises from the goal state; this allows
  4191     rules stemming from inductive sets to be applied in unstructured
  4192     scripts, while still benefitting from proper handling of non-atomic
  4193     statements; NB: major inductive premises need to be put first, all
  4194     the rest of the goal is passed through the induction;
  4195   - 'induct' proper support for mutual induction involving non-atomic
  4196     rule statements (uses the new concept of simultaneous goals, see
  4197     below);
  4198   - append all possible rule selections, but only use the first
  4199     success (no backtracking);
  4200   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4201   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4202   - added 'print_induct_rules' (covered by help item in recent Proof
  4203     General versions);
  4204   - moved induct/cases attributes to Pure, methods to Provers;
  4205   - generic method setup instantiated for FOL and HOL;
  4206 
  4207 * Pure: support multiple simultaneous goal statements, for example
  4208 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4209 meta-level mechanism, this acts as if several individual goals had
  4210 been stated separately; in particular common proof methods need to be
  4211 repeated in order to cover all claims; note that a single elimination
  4212 step is *not* sufficient to establish the two conjunctions, so this
  4213 fails:
  4214 
  4215   assume "A & B" then have A and B ..   (*".." fails*)
  4216 
  4217 better use "obtain" in situations as above; alternative refer to
  4218 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4219 
  4220 * Pure: proper integration with ``locales''; unlike the original
  4221 version by Florian Kammller, Isar locales package high-level proof
  4222 contexts rather than raw logical ones (e.g. we admit to include
  4223 attributes everywhere); operations on locales include merge and
  4224 rename; support for implicit arguments (``structures''); simultaneous
  4225 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4226 some examples;
  4227 
  4228 * Pure: the following commands have been ``localized'', supporting a
  4229 target locale specification "(in name)": 'lemma', 'theorem',
  4230 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4231 stored both within the locale and at the theory level (exported and
  4232 qualified by the locale name);
  4233 
  4234 * Pure: theory goals may now be specified in ``long'' form, with
  4235 ad-hoc contexts consisting of arbitrary locale elements. for example
  4236 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4237 definitions may be given, too); the result is a meta-level rule with
  4238 the context elements being discharged in the obvious way;
  4239 
  4240 * Pure: new proof command 'using' allows to augment currently used
  4241 facts after a goal statement ('using' is syntactically analogous to
  4242 'apply', but acts on the goal's facts only); this allows chained facts
  4243 to be separated into parts given before and after a claim, as in
  4244 ``from a and b have C using d and e <proof>'';
  4245 
  4246 * Pure: renamed "antecedent" case to "rule_context";
  4247 
  4248 * Pure: new 'judgment' command records explicit information about the
  4249 object-logic embedding (used by several tools internally); no longer
  4250 use hard-wired "Trueprop";
  4251 
  4252 * Pure: added 'corollary' command;
  4253 
  4254 * Pure: fixed 'token_translation' command;
  4255 
  4256 * Pure: removed obsolete 'exported' attribute;
  4257 
  4258 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4259 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4260 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4261 
  4262 * Pure: method 'atomize' presents local goal premises as object-level
  4263 statements (atomic meta-level propositions); setup controlled via
  4264 rewrite rules declarations of 'atomize' attribute; example
  4265 application: 'induct' method with proper rule statements in improper
  4266 proof *scripts*;
  4267 
  4268 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4269 now consider the syntactic context of assumptions, giving a better
  4270 chance to get type-inference of the arguments right (this is
  4271 especially important for locales);
  4272 
  4273 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4274 mode;
  4275 
  4276 * Pure/obtain: the formal conclusion "thesis", being marked as
  4277 ``internal'', may no longer be reference directly in the text;
  4278 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4279 situations;
  4280 
  4281 * Pure: generic 'sym' attribute which declares a rule both as pure
  4282 'elim?' and for the 'symmetric' operation;
  4283 
  4284 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4285 text; the fixed correlation with particular command syntax has been
  4286 discontinued;
  4287 
  4288 * Pure: new method 'rules' is particularly well-suited for proof
  4289 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4290 but often produces more compact proof terms with less detours;
  4291 
  4292 * Pure/Provers/classical: simplified integration with pure rule
  4293 attributes and methods; the classical "intro?/elim?/dest?"
  4294 declarations coincide with the pure ones; the "rule" method no longer
  4295 includes classically swapped intros; "intro" and "elim" methods no
  4296 longer pick rules from the context; also got rid of ML declarations
  4297 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4298 INCOMPATIBILITY;
  4299 
  4300 * Provers/classical: attribute 'swapped' produces classical inversions
  4301 of introduction rules;
  4302 
  4303 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4304 rules instead of full simplifier context; 'iff' attribute handles
  4305 conditional rules;
  4306 
  4307 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4308 
  4309 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4310 "(permissive)" option to recover old behavior;
  4311 
  4312 * HOL: 'inductive' no longer features separate (collective) attributes
  4313 for 'intros' (was found too confusing);
  4314 
  4315 * HOL: properly declared induction rules less_induct and
  4316 wf_induct_rule;
  4317 
  4318 
  4319 *** HOL ***
  4320 
  4321 * HOL: moved over to sane numeral syntax; the new policy is as
  4322 follows:
  4323 
  4324   - 0 and 1 are polymorphic constants, which are defined on any
  4325   numeric type (nat, int, real etc.);
  4326 
  4327   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4328   binary representation internally;
  4329 
  4330   - type nat has special constructor Suc, and generally prefers Suc 0
  4331   over 1::nat and Suc (Suc 0) over 2::nat;
  4332 
  4333 This change may cause significant problems of INCOMPATIBILITY; here
  4334 are some hints on converting existing sources:
  4335 
  4336   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4337   entities, so expressions involving "-" (unary or binary minus) need
  4338   to be spaced properly;
  4339 
  4340   - existing occurrences of "1" may need to be constraint "1::nat" or
  4341   even replaced by Suc 0; similar for old "2";
  4342 
  4343   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4344 
  4345   - remove all special provisions on numerals in proofs;
  4346 
  4347 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4348 representation (depends on bin_arith_simps in the default context);
  4349 
  4350 * HOL: symbolic syntax for x^2 (numeral 2);
  4351 
  4352 * HOL: the class of all HOL types is now called "type" rather than
  4353 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4354 in axclass/classes, instance/arities, and (usually rare) occurrences
  4355 in typings (of consts etc.); internally the class is called
  4356 "HOL.type", ML programs should refer to HOLogic.typeS;
  4357 
  4358 * HOL/record package improvements:
  4359   - new derived operations "fields" to build a partial record section,
  4360     "extend" to promote a fixed record to a record scheme, and
  4361     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4362     declared as simp by default;
  4363   - shared operations ("more", "fields", etc.) now need to be always
  4364     qualified) --- potential INCOMPATIBILITY;
  4365   - removed "make_scheme" operations (use "make" with "extend") --
  4366     INCOMPATIBILITY;
  4367   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4368   - provides cases/induct rules for use with corresponding Isar
  4369     methods (for concrete records, record schemes, concrete more
  4370     parts, and schematic more parts -- in that order);
  4371   - internal definitions directly based on a light-weight abstract
  4372     theory of product types over typedef rather than datatype;
  4373 
  4374 * HOL: generic code generator for generating executable ML code from
  4375 specifications; specific support for HOL constructs such as inductive
  4376 datatypes and sets, as well as recursive functions; can be invoked
  4377 via 'generate_code' theory section;
  4378 
  4379 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4380 
  4381 * HOL: consolidated and renamed several theories.  In particular:
  4382         Ord.thy has been absorbed into HOL.thy
  4383         String.thy has been absorbed into List.thy
  4384 
  4385 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4386 (beware of argument permutation!);
  4387 
  4388 * HOL: linorder_less_split superseded by linorder_cases;
  4389 
  4390 * HOL/List: "nodups" renamed to "distinct";
  4391 
  4392 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4393 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4394   - Ex_def has changed, now need to use some_eq_ex
  4395 
  4396 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4397 in this (rare) case use:
  4398 
  4399   delSWrapper "split_all_tac"
  4400   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4401 
  4402 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4403 MAY FAIL;
  4404 
  4405 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4406 Isabelle's type classes, ^ on functions and relations has too general
  4407 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4408 necessary to attach explicit type constraints;
  4409 
  4410 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4411 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4412 renamed accordingly (eg "compI" -> "rel_compI").
  4413 
  4414 * HOL: syntax translations now work properly with numerals and records
  4415 expressions;
  4416 
  4417 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4418 of "lam" -- INCOMPATIBILITY;
  4419 
  4420 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4421 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4422 renamed "Product_Type.unit";
  4423 
  4424 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4425 
  4426 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4427 the "cases" method);
  4428 
  4429 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4430 Florian Kammller);
  4431 
  4432 * HOL/IMP: updated and converted to new-style theory format; several
  4433 parts turned into readable document, with proper Isar proof texts and
  4434 some explanations (by Gerwin Klein);
  4435 
  4436 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4437 
  4438 * HOL-Hyperreal is now a logic image;
  4439 
  4440 
  4441 *** HOLCF ***
  4442 
  4443 * Isar: consts/constdefs supports mixfix syntax for continuous
  4444 operations;
  4445 
  4446 * Isar: domain package adapted to new-style theory format, e.g. see
  4447 HOLCF/ex/Dnat.thy;
  4448 
  4449 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4450 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4451 lift.induct_tac, always use UU instead of Undef;
  4452 
  4453 * HOLCF/IMP: updated and converted to new-style theory;
  4454 
  4455 
  4456 *** ZF ***
  4457 
  4458 * Isar: proper integration of logic-specific tools and packages,
  4459 including theory commands '(co)inductive', '(co)datatype',
  4460 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4461 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4462 
  4463 * theory Main no longer includes AC; for the Axiom of Choice, base
  4464 your theory on Main_ZFC;
  4465 
  4466 * the integer library now covers quotients and remainders, with many
  4467 laws relating division to addition, multiplication, etc.;
  4468 
  4469 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4470 typeless version of the formalism;
  4471 
  4472 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4473 format;
  4474 
  4475 * ZF/Induct: new directory for examples of inductive definitions,
  4476 including theory Multiset for multiset orderings; converted to
  4477 new-style theory format;
  4478 
  4479 * ZF: many new theorems about lists, ordinals, etc.;
  4480 
  4481 
  4482 *** General ***
  4483 
  4484 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4485 variable proof controls level of detail: 0 = no proofs (only oracle
  4486 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4487 also ref manual for further ML interfaces;
  4488 
  4489 * Pure/axclass: removed obsolete ML interface
  4490 goal_subclass/goal_arity;
  4491 
  4492 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4493 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4494 separate tokens, so expressions involving minus need to be spaced
  4495 properly;
  4496 
  4497 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4498 rather than "infixl" or "infixr";
  4499 
  4500 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4501 sort constraint specifications in type inference; e.g. "x::_::foo"
  4502 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4503 type variable);
  4504 
  4505 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4506 control output of nested => (types); the default behavior is
  4507 "type_brackets";
  4508 
  4509 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4510 tokens into AST constants;
  4511 
  4512 * Pure/syntax: prefer later declarations of translations and print
  4513 translation functions; potential INCOMPATIBILITY: need to reverse
  4514 multiple declarations for same syntax element constant;
  4515 
  4516 * Pure/show_hyps reset by default (in accordance to existing Isar
  4517 practice);
  4518 
  4519 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4520 addSafter;
  4521 
  4522 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4523 as well;
  4524 
  4525 * system: tested support for MacOS X; should be able to get Isabelle +
  4526 Proof General to work in a plain Terminal after installing Poly/ML
  4527 (e.g. from the Isabelle distribution area) and GNU bash alone
  4528 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4529 support requires further installations, e.g. from
  4530 http://fink.sourceforge.net/);
  4531 
  4532 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4533 
  4534 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4535 of 40 MB), cf. ML_OPTIONS;
  4536 
  4537 * system: Proof General keywords specification is now part of the
  4538 Isabelle distribution (see etc/isar-keywords.el);
  4539 
  4540 * system: support for persistent Proof General sessions (refrain from
  4541 outdating all loaded theories on startup); user may create writable
  4542 logic images like this: ``isabelle -q HOL Test'';
  4543 
  4544 * system: smart selection of Isabelle process versus Isabelle
  4545 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4546 run both "isabelle" and "Isabelle" even if file names are badly
  4547 damaged (executable inspects the case of the first letter of its own
  4548 name); added separate "isabelle-process" and "isabelle-interface";
  4549 
  4550 * system: refrain from any attempt at filtering input streams; no
  4551 longer support ``8bit'' encoding of old isabelle font, instead proper
  4552 iso-latin characters may now be used; the related isatools
  4553 "symbolinput" and "nonascii" have disappeared as well;
  4554 
  4555 * system: removed old "xterm" interface (the print modes "xterm" and
  4556 "xterm_color" are still available for direct use in a suitable
  4557 terminal);
  4558 
  4559 
  4560 
  4561 New in Isabelle99-2 (February 2001)
  4562 -----------------------------------
  4563 
  4564 *** Overview of INCOMPATIBILITIES ***
  4565 
  4566 * HOL: please note that theories in the Library and elsewhere often use the
  4567 new-style (Isar) format; to refer to their theorems in an ML script you must
  4568 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4569 
  4570 * HOL: inductive package no longer splits induction rule aggressively,
  4571 but only as far as specified by the introductions given; the old
  4572 format may be recovered via ML function complete_split_rule or attribute
  4573 'split_rule (complete)';
  4574 
  4575 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4576 gfp_Tarski to gfp_unfold;
  4577 
  4578 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4579 
  4580 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4581 relation); infix "^^" has been renamed "``"; infix "``" has been
  4582 renamed "`"; "univalent" has been renamed "single_valued";
  4583 
  4584 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4585 operation;
  4586 
  4587 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4588 
  4589 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4590 
  4591 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4592 consequence, it is no longer monotonic wrt. the local goal context
  4593 (which is now passed through the inductive cases);
  4594 
  4595 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4596 \<gg> to \<ggreater>;
  4597 
  4598 
  4599 *** Document preparation ***
  4600 
  4601 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4602 available: are "it" for near math-mode best-style output, "sl" for
  4603 slanted text style, and "tt" for plain type-writer; if no
  4604 \isabellestyle command is given, output is according to slanted
  4605 type-writer);
  4606 
  4607 * support sub/super scripts (for single symbols only), input syntax is
  4608 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4609 
  4610 * some more standard symbols; see Appendix A of the system manual for
  4611 the complete list of symbols defined in isabellesym.sty;
  4612 
  4613 * improved isabelle style files; more abstract symbol implementation
  4614 (should now use \isamath{...} and \isatext{...} in custom symbol
  4615 definitions);
  4616 
  4617 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4618 state; Note that presentation of goal states does not conform to
  4619 actual human-readable proof documents.  Please do not include goal
  4620 states into document output unless you really know what you are doing!
  4621 
  4622 * proper indentation of antiquoted output with proportional LaTeX
  4623 fonts;
  4624 
  4625 * no_document ML operator temporarily disables LaTeX document
  4626 generation;
  4627 
  4628 * isatool unsymbolize tunes sources for plain ASCII communication;
  4629 
  4630 
  4631 *** Isar ***
  4632 
  4633 * Pure: Isar now suffers initial goal statements to contain unbound
  4634 schematic variables (this does not conform to actual readable proof
  4635 documents, due to unpredictable outcome and non-compositional proof
  4636 checking); users who know what they are doing may use schematic goals
  4637 for Prolog-style synthesis of proven results;
  4638 
  4639 * Pure: assumption method (an implicit finishing) now handles actual
  4640 rules as well;
  4641 
  4642 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4643 initial goal, declare "that" only as Pure intro (only for single
  4644 steps); the "that" rule assumption may now be involved in implicit
  4645 finishing, thus ".." becomes a feasible for trivial obtains;
  4646 
  4647 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4648 instance proofs may be performed by "..";
  4649 
  4650 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4651 statements as well;
  4652 
  4653 * Pure: more robust selection of calculational rules;
  4654 
  4655 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4656 rule (as well as the assumption rule);
  4657 
  4658 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4659 lemmas, using the graph browser tool;
  4660 
  4661 * Pure: predict failure of "show" in interactive mode;
  4662 
  4663 * Pure: 'thms_containing' now takes actual terms as arguments;
  4664 
  4665 * HOL: improved method 'induct' --- now handles non-atomic goals
  4666 (potential INCOMPATIBILITY); tuned error handling;
  4667 
  4668 * HOL: cases and induct rules now provide explicit hints about the
  4669 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4670 any remaining facts are inserted into the goal verbatim;
  4671 
  4672 * HOL: local contexts (aka cases) may now contain term bindings as
  4673 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4674 the result to be shown in each case;
  4675 
  4676 * HOL: added 'recdef_tc' command;
  4677 
  4678 * isatool convert assists in eliminating legacy ML scripts;
  4679 
  4680 
  4681 *** HOL ***
  4682 
  4683 * HOL/Library: a collection of generic theories to be used together
  4684 with main HOL; the theory loader path already includes this directory
  4685 by default; the following existing theories have been moved here:
  4686 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4687 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4688 
  4689 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4690 modelling and verification task performed in Isabelle/HOL +
  4691 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4692 
  4693 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4694 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4695 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4696 'domain', this makes the theory consistent with mathematical
  4697 literature;
  4698 
  4699 * HOL basics: added overloaded operations "inverse" and "divide"
  4700 (infix "/"), syntax for generic "abs" operation, generic summation
  4701 operator \<Sum>;
  4702 
  4703 * HOL/typedef: simplified package, provide more useful rules (see also
  4704 HOL/subset.thy);
  4705 
  4706 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4707 now expressed as a proper nested rule (old-style tactic scripts may
  4708 require atomize_strip_tac to cope with non-atomic premises);
  4709 
  4710 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4711 to "split_conv" (old name still available for compatibility);
  4712 
  4713 * HOL: improved concrete syntax for strings (e.g. allows translation
  4714 rules with string literals);
  4715 
  4716 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4717  and Fleuriot's mechanization of analysis, including the transcendental
  4718  functions for the reals;
  4719 
  4720 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4721 
  4722 
  4723 *** CTT ***
  4724 
  4725 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4726 "lam" is displayed as TWO lambda-symbols
  4727 
  4728 * CTT: theory Main now available, containing everything (that is, Bool
  4729 and Arith);
  4730 
  4731 
  4732 *** General ***
  4733 
  4734 * Pure: the Simplifier has been implemented properly as a derived rule
  4735 outside of the actual kernel (at last!); the overall performance
  4736 penalty in practical applications is about 50%, while reliability of
  4737 the Isabelle inference kernel has been greatly improved;
  4738 
  4739 * print modes "brackets" and "no_brackets" control output of nested =>
  4740 (types) and ==> (props); the default behaviour is "brackets";
  4741 
  4742 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4743 as assumptions as well;
  4744 
  4745 * system: support Poly/ML 4.0;
  4746 
  4747 * system: isatool install handles KDE version 1 or 2;
  4748 
  4749 
  4750 
  4751 New in Isabelle99-1 (October 2000)
  4752 ----------------------------------
  4753 
  4754 *** Overview of INCOMPATIBILITIES ***
  4755 
  4756 * HOL: simplification of natural numbers is much changed; to partly
  4757 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4758 issue the following ML commands:
  4759 
  4760   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4761   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4762 
  4763 * HOL: simplification no longer dives into case-expressions; this is
  4764 controlled by "t.weak_case_cong" for each datatype t;
  4765 
  4766 * HOL: nat_less_induct renamed to less_induct;
  4767 
  4768 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4769 fixsome to patch .thy and .ML sources automatically;
  4770 
  4771   select_equality  -> some_equality
  4772   select_eq_Ex     -> some_eq_ex
  4773   selectI2EX       -> someI2_ex
  4774   selectI2         -> someI2
  4775   selectI          -> someI
  4776   select1_equality -> some1_equality
  4777   Eps_sym_eq       -> some_sym_eq_trivial
  4778   Eps_eq           -> some_eq_trivial
  4779 
  4780 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4781 
  4782 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4783 instead);
  4784 
  4785 * HOL: the recursion equations generated by 'recdef' are now called
  4786 f.simps instead of f.rules;
  4787 
  4788 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4789 
  4790 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4791 sometimes be needed;
  4792 
  4793 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4794 
  4795 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4796 
  4797 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4798 product is now "<*>" instead of "Times"; the lexicographic product is
  4799 now "<*lex*>" instead of "**";
  4800 
  4801 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4802 of main HOL, but was unused); better use HOL's datatype package;
  4803 
  4804 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4805 the old syntax may be recovered as follows:
  4806 
  4807   syntax (symbols)
  4808     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4809       (infixl "\\<oplus>" 100)
  4810 
  4811 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4812 
  4813 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4814 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4815 internally;
  4816 
  4817 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4818 changed from A/r to A//r;
  4819 
  4820 * ZF: new treatment of arithmetic (nat & int) may break some old
  4821 proofs;
  4822 
  4823 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4824 rulify -> rule_format, elimify -> elim_format, ...);
  4825 
  4826 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4827 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4828 should have to change intro!! to intro? only); replaced "delrule" by
  4829 "rule del";
  4830 
  4831 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4832 
  4833 * Provers: strengthened force_tac by using new first_best_tac;
  4834 
  4835 * LaTeX document preparation: several changes of isabelle.sty (see
  4836 lib/texinputs);
  4837 
  4838 
  4839 *** Document preparation ***
  4840 
  4841 * formal comments (text blocks etc.) in new-style theories may now
  4842 contain antiquotations of thm/prop/term/typ/text to be presented
  4843 according to latex print mode; concrete syntax is like this:
  4844 @{term[show_types] "f(x) = a + x"};
  4845 
  4846 * isatool mkdir provides easy setup of Isabelle session directories,
  4847 including proper document sources;
  4848 
  4849 * generated LaTeX sources are now deleted after successful run
  4850 (isatool document -c); may retain a copy somewhere else via -D option
  4851 of isatool usedir;
  4852 
  4853 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4854 style files, achieving self-contained LaTeX sources and simplifying
  4855 LaTeX debugging;
  4856 
  4857 * old-style theories now produce (crude) LaTeX output as well;
  4858 
  4859 * browser info session directories are now self-contained (may be put
  4860 on WWW server seperately); improved graphs of nested sessions; removed
  4861 graph for 'all sessions';
  4862 
  4863 * several improvements in isabelle style files; \isabellestyle{it}
  4864 produces fake math mode output; \isamarkupheader is now \section by
  4865 default; see lib/texinputs/isabelle.sty etc.;
  4866 
  4867 
  4868 *** Isar ***
  4869 
  4870 * Isar/Pure: local results and corresponding term bindings are now
  4871 subject to Hindley-Milner polymorphism (similar to ML); this
  4872 accommodates incremental type-inference very nicely;
  4873 
  4874 * Isar/Pure: new derived language element 'obtain' supports
  4875 generalized existence reasoning;
  4876 
  4877 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4878 support accumulation of results, without applying any rules yet;
  4879 useful to collect intermediate results without explicit name
  4880 references, and for use with transitivity rules with more than 2
  4881 premises;
  4882 
  4883 * Isar/Pure: scalable support for case-analysis type proofs: new
  4884 'case' language element refers to local contexts symbolically, as
  4885 produced by certain proof methods; internally, case names are attached
  4886 to theorems as "tags";
  4887 
  4888 * Isar/Pure: theory command 'hide' removes declarations from
  4889 class/type/const name spaces;
  4890 
  4891 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4892 indicate potential overloading;
  4893 
  4894 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4895 
  4896 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4897 "{a,b,c}" instead of {a,b,c};
  4898 
  4899 * Isar/Pure now provides its own version of intro/elim/dest
  4900 attributes; useful for building new logics, but beware of confusion
  4901 with the version in Provers/classical;
  4902 
  4903 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4904 case name 'antecedent';
  4905 
  4906 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4907 to the current context is now done automatically);
  4908 
  4909 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4910 for definining proof methods in ML;
  4911 
  4912 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4913 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4914 most cases, one should have to change intro!! to intro? only);
  4915 replaced "delrule" by "rule del";
  4916 
  4917 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4918 'symmetric' attribute (the latter supercedes [RS sym]);
  4919 
  4920 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4921 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4922 well (including splits);
  4923 
  4924 * Isar/Provers: Simplifier and Classical methods now support all kind
  4925 of modifiers used in the past, including 'cong', 'iff', etc.
  4926 
  4927 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4928 of Simplifier and Classical reasoner);
  4929 
  4930 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4931 now support named cases; major packages (inductive, datatype, primrec,
  4932 recdef) support case names and properly name parameters;
  4933 
  4934 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4935 monotonicity conditions are extracted to be proven at end of
  4936 calculations;
  4937 
  4938 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4939 method anyway;
  4940 
  4941 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4942 split_if split_if_asm; datatype package provides theorems foo.splits =
  4943 foo.split foo.split_asm for each datatype;
  4944 
  4945 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4946 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4947 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4948 use "(cases (simplified))" method in proper proof texts);
  4949 
  4950 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4951 
  4952 * Isar: names of theorems etc. may be natural numbers as well;
  4953 
  4954 * Isar: 'pr' command: optional arguments for goals_limit and
  4955 ProofContext.prems_limit; no longer prints theory contexts, but only
  4956 proof states;
  4957 
  4958 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4959 additional print modes to be specified; e.g. "pr(latex)" will print
  4960 proof state according to the Isabelle LaTeX style;
  4961 
  4962 * Isar: improved support for emulating tactic scripts, including proof
  4963 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4964 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4965 (for HOL datatypes);
  4966 
  4967 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4968 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4969 'proof method scripts' have to be in depth-first order;
  4970 
  4971 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4972 
  4973 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4974 should instead use individual commands for printing items
  4975 (print_commands, print_methods etc.);
  4976 
  4977 * Isar: added 'nothing' --- the empty list of theorems;
  4978 
  4979 
  4980 *** HOL ***
  4981 
  4982 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4983 corresponding virtual machine and a specification of its bytecode
  4984 verifier and a lightweight bytecode verifier, including proofs of
  4985 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4986 Cornelia Pusch (see also the homepage of project Bali at
  4987 http://isabelle.in.tum.de/Bali/);
  4988 
  4989 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4990 Clemens Ballarin;
  4991 
  4992 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4993 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4994 Rasmussen;
  4995 
  4996 * HOL/Lattice: fundamental concepts of lattice theory and order
  4997 structures, including duals, properties of bounds versus algebraic
  4998 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4999 Theorem for complete lattices etc.; may also serve as a demonstration
  5000 for abstract algebraic reasoning using axiomatic type classes, and
  5001 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  5002 
  5003 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  5004 von Oheimb;
  5005 
  5006 * HOL/IMPP: extension of IMP with local variables and mutually
  5007 recursive procedures, by David von Oheimb;
  5008 
  5009 * HOL/Lambda: converted into new-style theory and document;
  5010 
  5011 * HOL/ex/Multiquote: example of multiple nested quotations and
  5012 anti-quotations -- basically a generalized version of de-Bruijn
  5013 representation; very useful in avoiding lifting of operations;
  5014 
  5015 * HOL/record: added general record equality rule to simpset; fixed
  5016 select-update simplification procedure to handle extended records as
  5017 well; admit "r" as field name;
  5018 
  5019 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  5020 other numeric types and also as the identity of groups, rings, etc.;
  5021 
  5022 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  5023 Types nat and int belong to this axclass;
  5024 
  5025 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  5026    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  5027    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  5028   two terms #m*u and #n*u are replaced by #(m+n)*u
  5029     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  5030   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  5031     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  5032 
  5033 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  5034 powerful prover for predicate logic but knows nothing of clasets; see
  5035 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  5036 
  5037 * HOL: new version of "case_tac" subsumes both boolean case split and
  5038 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  5039 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  5040 
  5041 * HOL: simplification no longer dives into case-expressions: only the
  5042 selector expression is simplified, but not the remaining arms; to
  5043 enable full simplification of case-expressions for datatype t, you may
  5044 remove t.weak_case_cong from the simpset, either globally (Delcongs
  5045 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  5046 
  5047 * HOL/recdef: the recursion equations generated by 'recdef' for
  5048 function 'f' are now called f.simps instead of f.rules; if all
  5049 termination conditions are proved automatically, these simplification
  5050 rules are added to the simpset, as in primrec; rules may be named
  5051 individually as well, resulting in a separate list of theorems for
  5052 each equation;
  5053 
  5054 * HOL/While is a new theory that provides a while-combinator. It
  5055 permits the definition of tail-recursive functions without the
  5056 provision of a termination measure. The latter is necessary once the
  5057 invariant proof rule for while is applied.
  5058 
  5059 * HOL: new (overloaded) notation for the set of elements below/above
  5060 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5061 
  5062 * HOL: theorems impI, allI, ballI bound as "strip";
  5063 
  5064 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5065 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5066 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5067 
  5068 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5069 
  5070 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5071 main HOL, but was unused);
  5072 
  5073 * HOL: fewer consts declared as global (e.g. have to refer to
  5074 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5075 
  5076 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5077 in case of overlap with user translations (e.g. judgements over
  5078 tuples); (note that the underlying logical represenation is still
  5079 bogus);
  5080 
  5081 
  5082 *** ZF ***
  5083 
  5084 * ZF: simplification automatically cancels common terms in arithmetic
  5085 expressions over nat and int;
  5086 
  5087 * ZF: new treatment of nat to minimize type-checking: all operators
  5088 coerce their operands to a natural number using the function natify,
  5089 making the algebraic laws unconditional;
  5090 
  5091 * ZF: as above, for int: operators coerce their operands to an integer
  5092 using the function intify;
  5093 
  5094 * ZF: the integer library now contains many of the usual laws for the
  5095 orderings, including $<=, and monotonicity laws for $+ and $*;
  5096 
  5097 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5098 simplification;
  5099 
  5100 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5101 to the simplifier and classical reasoner simultaneously;
  5102 
  5103 
  5104 *** General ***
  5105 
  5106 * Provers: blast_tac now handles actual object-logic rules as
  5107 assumptions; note that auto_tac uses blast_tac internally as well;
  5108 
  5109 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5110 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5111 
  5112 * Provers: delrules now handles destruct rules as well (no longer need
  5113 explicit make_elim);
  5114 
  5115 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5116   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5117 use instead the strong form,
  5118   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5119 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5120 from destruct-rules;
  5121 
  5122 * Provers: Simplifier.easy_setup provides a fast path to basic
  5123 Simplifier setup for new object-logics;
  5124 
  5125 * Pure: AST translation rules no longer require constant head on LHS;
  5126 
  5127 * Pure: improved name spaces: ambiguous output is qualified; support
  5128 for hiding of names;
  5129 
  5130 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5131 XSYMBOL_HOME; no longer need to do manual configuration in most
  5132 situations;
  5133 
  5134 * system: compression of ML heaps images may now be controlled via -c
  5135 option of isabelle and isatool usedir (currently only observed by
  5136 Poly/ML);
  5137 
  5138 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5139 useful for remote X11);
  5140 
  5141 * system: provide TAGS file for Isabelle sources;
  5142 
  5143 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5144 order;
  5145 
  5146 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5147 timing flag supersedes proof_timing and Toplevel.trace;
  5148 
  5149 * ML: new combinators |>> and |>>> for incremental transformations
  5150 with secondary results (e.g. certain theory extensions):
  5151 
  5152 * ML: PureThy.add_defs gets additional argument to indicate potential
  5153 overloading (usually false);
  5154 
  5155 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5156 results;
  5157 
  5158 
  5159 
  5160 New in Isabelle99 (October 1999)
  5161 --------------------------------
  5162 
  5163 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5164 
  5165 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5166 are no longer simplified.  (This allows the simplifier to unfold recursive
  5167 functional programs.)  To restore the old behaviour, declare
  5168 
  5169     Delcongs [if_weak_cong];
  5170 
  5171 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5172 complement;
  5173 
  5174 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5175 
  5176 * HOL/datatype: mutual_induct_tac no longer exists --
  5177   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5178 
  5179 * HOL/typedef: fixed type inference for representing set; type
  5180 arguments now have to occur explicitly on the rhs as type constraints;
  5181 
  5182 * ZF: The con_defs part of an inductive definition may no longer refer
  5183 to constants declared in the same theory;
  5184 
  5185 * HOL, ZF: the function mk_cases, generated by the inductive
  5186 definition package, has lost an argument.  To simplify its result, it
  5187 uses the default simpset instead of a supplied list of theorems.
  5188 
  5189 * HOL/List: the constructors of type list are now Nil and Cons;
  5190 
  5191 * Simplifier: the type of the infix ML functions
  5192         setSSolver addSSolver setSolver addSolver
  5193 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5194 for packaging solvers. A solver is created via
  5195         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5196 where the string argument is only a comment.
  5197 
  5198 
  5199 *** Proof tools ***
  5200 
  5201 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5202 decision procedure for linear arithmetic. Currently it is used for
  5203 types `nat', `int', and `real' in HOL (see below); it can, should and
  5204 will be instantiated for other types and logics as well.
  5205 
  5206 * The simplifier now accepts rewrite rules with flexible heads, eg
  5207      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5208   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5209   matching.
  5210 
  5211 
  5212 *** General ***
  5213 
  5214 * New Isabelle/Isar subsystem provides an alternative to traditional
  5215 tactical theorem proving; together with the ProofGeneral/isar user
  5216 interface it offers an interactive environment for developing human
  5217 readable proof documents (Isar == Intelligible semi-automated
  5218 reasoning); for further information see isatool doc isar-ref,
  5219 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5220 
  5221 * improved and simplified presentation of theories: better HTML markup
  5222 (including colors), graph views in several sizes; isatool usedir now
  5223 provides a proper interface for user theories (via -P option); actual
  5224 document preparation based on (PDF)LaTeX is available as well (for
  5225 new-style theories only); see isatool doc system for more information;
  5226 
  5227 * native support for Proof General, both for classic Isabelle and
  5228 Isabelle/Isar;
  5229 
  5230 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5231 using the graph browser tool;
  5232 
  5233 * Isabelle manuals now also available as PDF;
  5234 
  5235 * theory loader rewritten from scratch (may not be fully
  5236 bug-compatible); old loadpath variable has been replaced by show_path,
  5237 add_path, del_path, reset_path functions; new operations such as
  5238 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5239 isatool doc ref);
  5240 
  5241 * improved isatool install: option -k creates KDE application icon,
  5242 option -p DIR installs standalone binaries;
  5243 
  5244 * added ML_PLATFORM setting (useful for cross-platform installations);
  5245 more robust handling of platform specific ML images for SML/NJ;
  5246 
  5247 * the settings environment is now statically scoped, i.e. it is never
  5248 created again in sub-processes invoked from isabelle, isatool, or
  5249 Isabelle;
  5250 
  5251 * path element specification '~~' refers to '$ISABELLE_HOME';
  5252 
  5253 * in locales, the "assumes" and "defines" parts may be omitted if
  5254 empty;
  5255 
  5256 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5257 long arrows);
  5258 
  5259 * new print_mode "HTML";
  5260 
  5261 * new flag show_tags controls display of tags of theorems (which are
  5262 basically just comments that may be attached by some tools);
  5263 
  5264 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5265 mode and goal output format:
  5266 
  5267 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5268 244c244
  5269 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5270 ---
  5271 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5272 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5273 181c181
  5274 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5275 ---
  5276 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5277 
  5278 * function bind_thms stores lists of theorems (cf. bind_thm);
  5279 
  5280 * new shorthand tactics ftac, eatac, datac, fatac;
  5281 
  5282 * qed (and friends) now accept "" as result name; in that case the
  5283 theorem is not stored, but proper checks and presentation of the
  5284 result still apply;
  5285 
  5286 * theorem database now also indexes constants "Trueprop", "all",
  5287 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5288 
  5289 
  5290 *** HOL ***
  5291 
  5292 ** HOL arithmetic **
  5293 
  5294 * There are now decision procedures for linear arithmetic over nat and
  5295 int:
  5296 
  5297 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5298 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5299 are treated as atomic; subformulae not involving type `nat' or `int'
  5300 are ignored; quantified subformulae are ignored unless they are
  5301 positive universal or negative existential. The tactic has to be
  5302 invoked by hand and can be a little bit slow. In particular, the
  5303 running time is exponential in the number of occurrences of `min' and
  5304 `max', and `-' on `nat'.
  5305 
  5306 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5307 (negated) (in)equalities among the premises and the conclusion into
  5308 account (i.e. no compound formulae) and does not know about `min' and
  5309 `max', and `-' on `nat'. It is fast and is used automatically by the
  5310 simplifier.
  5311 
  5312 NB: At the moment, these decision procedures do not cope with mixed
  5313 nat/int formulae where the two parts interact, such as `m < n ==>
  5314 int(m) < int(n)'.
  5315 
  5316 * HOL/Numeral provides a generic theory of numerals (encoded
  5317 efficiently as bit strings); setup for types nat/int/real is in place;
  5318 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5319 int, existing theories and proof scripts may require a few additional
  5320 type constraints;
  5321 
  5322 * integer division and remainder can now be performed on constant
  5323 arguments;
  5324 
  5325 * many properties of integer multiplication, division and remainder
  5326 are now available;
  5327 
  5328 * An interface to the Stanford Validity Checker (SVC) is available through the
  5329 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5330 are proved automatically.  SVC must be installed separately, and its results
  5331 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5332 invocation of the underlying oracle).  For SVC see
  5333   http://verify.stanford.edu/SVC
  5334 
  5335 * IsaMakefile: the HOL-Real target now builds an actual image;
  5336 
  5337 
  5338 ** HOL misc **
  5339 
  5340 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5341 (in Isabelle/Isar) -- by Gertrud Bauer;
  5342 
  5343 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5344 analysis for assembly languages with subtypes;
  5345 
  5346 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5347 -- avoids syntactic ambiguities and treats state, transition, and
  5348 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5349 changed syntax and (many) tactics;
  5350 
  5351 * HOL/inductive: Now also handles more general introduction rules such
  5352   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5353   theorems are now maintained within the theory (maintained via the
  5354   "mono" attribute);
  5355 
  5356 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5357   (using function types) such as
  5358 
  5359   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5360 
  5361 * HOL/record: record_simproc (part of the default simpset) takes care
  5362 of selectors applied to updated records; record_split_tac is no longer
  5363 part of the default claset; update_defs may now be removed from the
  5364 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5365 
  5366   claset_ref () := claset() addSWrapper record_split_wrapper;
  5367   Delsimprocs [record_simproc]
  5368 
  5369 * HOL/typedef: fixed type inference for representing set; type
  5370 arguments now have to occur explicitly on the rhs as type constraints;
  5371 
  5372 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5373 names rather than an ML expression;
  5374 
  5375 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5376 supplied later.  Program schemes can be defined, such as
  5377     "While B C s = (if B s then While B C (C s) else s)"
  5378 where the well-founded relation can be chosen after B and C have been given.
  5379 
  5380 * HOL/List: the constructors of type list are now Nil and Cons;
  5381 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5382 course, ML tools referring to List.list.op # etc. have to be adapted;
  5383 
  5384 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5385 disabled by default; run isabelle with option -m HOL to get back to
  5386 the original Gordon/HOL-style output;
  5387 
  5388 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5389 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5390 
  5391 * HOL basic syntax simplified (more orthogonal): all variants of
  5392 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5393 Eps operator is provided as well: "SOME x. P[x]";
  5394 
  5395 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5396 
  5397 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5398 thus available for user theories;
  5399 
  5400 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5401 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5402 time;
  5403 
  5404 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5405 several times and then mp;
  5406 
  5407 
  5408 *** LK ***
  5409 
  5410 * the notation <<...>> is now available as a notation for sequences of
  5411 formulas;
  5412 
  5413 * the simplifier is now installed
  5414 
  5415 * the axiom system has been generalized (thanks to Soren Heilmann)
  5416 
  5417 * the classical reasoner now has a default rule database
  5418 
  5419 
  5420 *** ZF ***
  5421 
  5422 * new primrec section allows primitive recursive functions to be given
  5423 directly (as in HOL) over datatypes and the natural numbers;
  5424 
  5425 * new tactics induct_tac and exhaust_tac for induction (or case
  5426 analysis) over datatypes and the natural numbers;
  5427 
  5428 * the datatype declaration of type T now defines the recursor T_rec;
  5429 
  5430 * simplification automatically does freeness reasoning for datatype
  5431 constructors;
  5432 
  5433 * automatic type-inference, with AddTCs command to insert new
  5434 type-checking rules;
  5435 
  5436 * datatype introduction rules are now added as Safe Introduction rules
  5437 to the claset;
  5438 
  5439 * the syntax "if P then x else y" is now available in addition to
  5440 if(P,x,y);
  5441 
  5442 
  5443 *** Internal programming interfaces ***
  5444 
  5445 * tuned simplifier trace output; new flag debug_simp;
  5446 
  5447 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5448 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5449 
  5450 * AxClass.axclass_tac lost the theory argument;
  5451 
  5452 * tuned current_goals_markers semantics: begin / end goal avoids
  5453 printing empty lines;
  5454 
  5455 * removed prs and prs_fn hook, which was broken because it did not
  5456 include \n in its semantics, forcing writeln to add one
  5457 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5458 string -> unit if you really want to output text without newline;
  5459 
  5460 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5461 plain output, interface builders may have to enable 'isabelle_font'
  5462 mode to get Isabelle font glyphs as before;
  5463 
  5464 * refined token_translation interface; INCOMPATIBILITY: output length
  5465 now of type real instead of int;
  5466 
  5467 * theory loader actions may be traced via new ThyInfo.add_hook
  5468 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5469 your own database of information attached to *whole* theories -- as
  5470 opposed to intra-theory data slots offered via TheoryDataFun;
  5471 
  5472 * proper handling of dangling sort hypotheses (at last!);
  5473 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5474 extra sort hypotheses that can be witnessed from the type signature;
  5475 the force_strip_shyps flag is gone, any remaining shyps are simply
  5476 left in the theorem (with a warning issued by strip_shyps_warning);
  5477 
  5478 
  5479 
  5480 New in Isabelle98-1 (October 1998)
  5481 ----------------------------------
  5482 
  5483 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5484 
  5485 * several changes of automated proof tools;
  5486 
  5487 * HOL: major changes to the inductive and datatype packages, including
  5488 some minor incompatibilities of theory syntax;
  5489 
  5490 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5491 called `inj_on';
  5492 
  5493 * HOL: removed duplicate thms in Arith:
  5494   less_imp_add_less  should be replaced by  trans_less_add1
  5495   le_imp_add_le      should be replaced by  trans_le_add1
  5496 
  5497 * HOL: unary minus is now overloaded (new type constraints may be
  5498 required);
  5499 
  5500 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5501 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5502 now taken as an integer constant.
  5503 
  5504 * Pure: ML function 'theory_of' renamed to 'theory';
  5505 
  5506 
  5507 *** Proof tools ***
  5508 
  5509 * Simplifier:
  5510   1. Asm_full_simp_tac is now more aggressive.
  5511      1. It will sometimes reorient premises if that increases their power to
  5512         simplify.
  5513      2. It does no longer proceed strictly from left to right but may also
  5514         rotate premises to achieve further simplification.
  5515      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5516      old Asm_full_simp_tac in that it does not rotate premises.
  5517   2. The simplifier now knows a little bit about nat-arithmetic.
  5518 
  5519 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5520 allows for selected deletion of wrappers, by introduction of names for
  5521 wrapper functionals.  This implies that addbefore, addSbefore,
  5522 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5523 and that adding two tactics with the same name overwrites the first
  5524 one (emitting a warning).
  5525   type wrapper = (int -> tactic) -> (int -> tactic)
  5526   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5527   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5528   delWrapper, delSWrapper: claset *  string            -> claset
  5529   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5530 
  5531 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5532 semantics; addbefore now affects only the unsafe part of step_tac
  5533 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5534 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5535 by Force_tac;
  5536 
  5537 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5538 compWrapper; added safe wrapper (and access functions for it);
  5539 
  5540 * HOL/split_all_tac is now much faster and fails if there is nothing
  5541 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5542 and the names of the automatically generated variables have changed.
  5543 split_all_tac has moved within claset() from unsafe wrappers to safe
  5544 wrappers, which means that !!-bound variables are split much more
  5545 aggressively, and safe_tac and clarify_tac now split such variables.
  5546 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5547 Note: the same holds for record_split_tac, which does the job of
  5548 split_all_tac for record fields.
  5549 
  5550 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5551 permanently to the default simpset using Addsplits just like
  5552 Addsimps. They can be removed via Delsplits just like
  5553 Delsimps. Lower-case versions are also available.
  5554 
  5555 * HOL/Simplifier: The rule split_if is now part of the default
  5556 simpset. This means that the simplifier will eliminate all occurrences
  5557 of if-then-else in the conclusion of a goal. To prevent this, you can
  5558 either remove split_if completely from the default simpset by
  5559 `Delsplits [split_if]' or remove it in a specific call of the
  5560 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5561 other case splitting rules to/from the default simpset: every datatype
  5562 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5563 t is the name of the datatype).
  5564 
  5565 * Classical reasoner / Simplifier combination: new force_tac (and
  5566 derivatives Force_tac, force) combines rewriting and classical
  5567 reasoning (and whatever other tools) similarly to auto_tac, but is
  5568 aimed to solve the given subgoal completely.
  5569 
  5570 
  5571 *** General ***
  5572 
  5573 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5574 and `goalw': the theory is no longer needed as an explicit argument -
  5575 the current theory context is used; assumptions are no longer returned
  5576 at the ML-level unless one of them starts with ==> or !!; it is
  5577 recommended to convert to these new commands using isatool fixgoal
  5578 (backup your sources first!);
  5579 
  5580 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5581 the current theory context, and 'theory' to lookup stored theories;
  5582 
  5583 * new theory section 'locale' for declaring constants, assumptions and
  5584 definitions that have local scope;
  5585 
  5586 * new theory section 'nonterminals' for purely syntactic types;
  5587 
  5588 * new theory section 'setup' for generic ML setup functions
  5589 (e.g. package initialization);
  5590 
  5591 * the distribution now includes Isabelle icons: see
  5592 lib/logo/isabelle-{small,tiny}.xpm;
  5593 
  5594 * isatool install - install binaries with absolute references to
  5595 ISABELLE_HOME/bin;
  5596 
  5597 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5598 
  5599 * print mode 'emacs' reserved for Isamode;
  5600 
  5601 * support multiple print (ast) translations per constant name;
  5602 
  5603 * theorems involving oracles are now printed with a suffixed [!];
  5604 
  5605 
  5606 *** HOL ***
  5607 
  5608 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5609 
  5610 * HOL/inductive package reorganized and improved: now supports mutual
  5611 definitions such as
  5612 
  5613   inductive EVEN ODD
  5614     intrs
  5615       null "0 : EVEN"
  5616       oddI "n : EVEN ==> Suc n : ODD"
  5617       evenI "n : ODD ==> Suc n : EVEN"
  5618 
  5619 new theorem list "elims" contains an elimination rule for each of the
  5620 recursive sets; inductive definitions now handle disjunctive premises
  5621 correctly (also ZF);
  5622 
  5623 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5624 "mutual_induct" no longer exists - the induction rule is always
  5625 contained in "induct";
  5626 
  5627 
  5628 * HOL/datatype package re-implemented and greatly improved: now
  5629 supports mutually recursive datatypes such as
  5630 
  5631   datatype
  5632     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5633             | SUM ('a aexp) ('a aexp)
  5634             | DIFF ('a aexp) ('a aexp)
  5635             | NUM 'a
  5636   and
  5637     'a bexp = LESS ('a aexp) ('a aexp)
  5638             | AND ('a bexp) ('a bexp)
  5639             | OR ('a bexp) ('a bexp)
  5640 
  5641 as well as indirectly recursive datatypes such as
  5642 
  5643   datatype
  5644     ('a, 'b) term = Var 'a
  5645                   | App 'b ((('a, 'b) term) list)
  5646 
  5647 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5648 induction on mutually / indirectly recursive datatypes.
  5649 
  5650 Primrec equations are now stored in theory and can be accessed via
  5651 <function_name>.simps.
  5652 
  5653 INCOMPATIBILITIES:
  5654 
  5655   - Theories using datatypes must now have theory Datatype as an
  5656     ancestor.
  5657   - The specific <typename>.induct_tac no longer exists - use the
  5658     generic induct_tac instead.
  5659   - natE has been renamed to nat.exhaust - use exhaust_tac
  5660     instead of res_inst_tac ... natE. Note that the variable
  5661     names in nat.exhaust differ from the names in natE, this
  5662     may cause some "fragile" proofs to fail.
  5663   - The theorems split_<typename>_case and split_<typename>_case_asm
  5664     have been renamed to <typename>.split and <typename>.split_asm.
  5665   - Since default sorts of type variables are now handled correctly,
  5666     some datatype definitions may have to be annotated with explicit
  5667     sort constraints.
  5668   - Primrec definitions no longer require function name and type
  5669     of recursive argument.
  5670 
  5671 Consider using isatool fixdatatype to adapt your theories and proof
  5672 scripts to the new package (backup your sources first!).
  5673 
  5674 
  5675 * HOL/record package: considerably improved implementation; now
  5676 includes concrete syntax for record types, terms, updates; theorems
  5677 for surjective pairing and splitting !!-bound record variables; proof
  5678 support is as follows:
  5679 
  5680   1) standard conversions (selectors or updates applied to record
  5681 constructor terms) are part of the standard simpset;
  5682 
  5683   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5684 made part of standard simpset and claset via addIffs;
  5685 
  5686   3) a tactic for record field splitting (record_split_tac) is part of
  5687 the standard claset (addSWrapper);
  5688 
  5689 To get a better idea about these rules you may retrieve them via
  5690 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5691 the name of your record type.
  5692 
  5693 The split tactic 3) conceptually simplifies by the following rule:
  5694 
  5695   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5696 
  5697 Thus any record variable that is bound by meta-all will automatically
  5698 blow up into some record constructor term, consequently the
  5699 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5700 solve record problems automatically.
  5701 
  5702 
  5703 * reorganized the main HOL image: HOL/Integ and String loaded by
  5704 default; theory Main includes everything;
  5705 
  5706 * automatic simplification of integer sums and comparisons, using cancellation;
  5707 
  5708 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5709 
  5710 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5711 
  5712 * many new identities for unions, intersections, set difference, etc.;
  5713 
  5714 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5715 called split_if, split_split, split_sum_case and split_nat_case (to go
  5716 with add/delsplits);
  5717 
  5718 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5719 (?x::unit) = (); this is made part of the default simpset, which COULD
  5720 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5721 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5722 unit_abs_eta_conv is added in order to counter the effect of
  5723 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5724 %u.f();
  5725 
  5726 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5727 makes more sense);
  5728 
  5729 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5730   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5731   disjointness reasoning but breaking a few old proofs.
  5732 
  5733 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5734 to 'converse' from 'inverse' (for compatibility with ZF and some
  5735 literature);
  5736 
  5737 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5738 the well-founded relation;
  5739 
  5740 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5741     Compl A.  The "Compl" syntax remains available as input syntax for this
  5742     release ONLY.
  5743 
  5744 * HOL/Update: new theory of function updates:
  5745     f(a:=b) == %x. if x=a then b else f x
  5746 may also be iterated as in f(a:=b,c:=d,...);
  5747 
  5748 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5749 
  5750 * HOL/List:
  5751   - new function list_update written xs[i:=v] that updates the i-th
  5752     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5753   - new function `upt' written [i..j(] which generates the list
  5754     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5755     bound write [i..j], which is a shorthand for [i..j+1(].
  5756   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5757 
  5758 * HOL/Arith:
  5759   - removed 'pred' (predecessor) function;
  5760   - generalized some theorems about n-1;
  5761   - many new laws about "div" and "mod";
  5762   - new laws about greatest common divisors (see theory ex/Primes);
  5763 
  5764 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5765 instead of "inverse";
  5766 
  5767 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5768   of the multiset ordering;
  5769 
  5770 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5771   (not included by default);
  5772 
  5773 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5774 
  5775 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5776   programs, i.e. different program variables may have different types.
  5777 
  5778 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5779   [previously, this check worked only if the rewrite rule was unconditional]
  5780   Now rew can involve either definitions or equalities (either == or =).
  5781 
  5782 
  5783 *** ZF ***
  5784 
  5785 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5786   only the theorems proved on ZF.ML;
  5787 
  5788 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5789   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5790   disjointness reasoning but breaking a few old proofs.
  5791 
  5792 * ZF/Update: new theory of function updates
  5793     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5794   may also be iterated as in f(a:=b,c:=d,...);
  5795 
  5796 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5797 
  5798 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5799   [previously, this check worked only if the rewrite rule was unconditional]
  5800   Now rew can involve either definitions or equalities (either == or =).
  5801 
  5802 * case_tac provided for compatibility with HOL
  5803     (like the old excluded_middle_tac, but with subgoals swapped)
  5804 
  5805 
  5806 *** Internal programming interfaces ***
  5807 
  5808 * Pure: several new basic modules made available for general use, see
  5809 also src/Pure/README;
  5810 
  5811 * improved the theory data mechanism to support encapsulation (data
  5812 kind name replaced by private Object.kind, acting as authorization
  5813 key); new type-safe user interface via functor TheoryDataFun; generic
  5814 print_data function becomes basically useless;
  5815 
  5816 * removed global_names compatibility flag -- all theory declarations
  5817 are qualified by default;
  5818 
  5819 * module Pure/Syntax now offers quote / antiquote translation
  5820 functions (useful for Hoare logic etc. with implicit dependencies);
  5821 see HOL/ex/Antiquote for an example use;
  5822 
  5823 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5824 cterm -> thm;
  5825 
  5826 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5827 subgoal;
  5828 
  5829 * Display.print_goals function moved to Locale.print_goals;
  5830 
  5831 * standard print function for goals supports current_goals_markers
  5832 variable for marking begin of proof, end of proof, start of goal; the
  5833 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5834 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5835 for example;
  5836 
  5837 
  5838 
  5839 New in Isabelle98 (January 1998)
  5840 --------------------------------
  5841 
  5842 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5843 
  5844 * changed lexical syntax of terms / types: dots made part of long
  5845 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5846 
  5847 * simpset (and claset) reference variable replaced by functions
  5848 simpset / simpset_ref;
  5849 
  5850 * no longer supports theory aliases (via merge) and non-trivial
  5851 implicit merge of thms' signatures;
  5852 
  5853 * most internal names of constants changed due to qualified names;
  5854 
  5855 * changed Pure/Sequence interface (see Pure/seq.ML);
  5856 
  5857 
  5858 *** General Changes ***
  5859 
  5860 * hierachically structured name spaces (for consts, types, axms, thms
  5861 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5862 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5863 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5864 long_names for fully qualified output names; NOTE: ML programs
  5865 (special tactics, packages etc.) referring to internal names may have
  5866 to be adapted to cope with fully qualified names; in case of severe
  5867 backward campatibility problems try setting 'global_names' at compile
  5868 time to have enrything declared within a flat name space; one may also
  5869 fine tune name declarations in theories via the 'global' and 'local'
  5870 section;
  5871 
  5872 * reimplemented the implicit simpset and claset using the new anytype
  5873 data filed in signatures; references simpset:simpset ref etc. are
  5874 replaced by functions simpset:unit->simpset and
  5875 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5876 to patch your ML files accordingly;
  5877 
  5878 * HTML output now includes theory graph data for display with Java
  5879 applet or isatool browser; data generated automatically via isatool
  5880 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5881 
  5882 * defs may now be conditional; improved rewrite_goals_tac to handle
  5883 conditional equations;
  5884 
  5885 * defs now admits additional type arguments, using TYPE('a) syntax;
  5886 
  5887 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5888 creates a new theory node; implicit merge of thms' signatures is
  5889 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5890 transfer:theory->thm->thm in (rare) cases;
  5891 
  5892 * improved handling of draft signatures / theories; draft thms (and
  5893 ctyps, cterms) are automatically promoted to real ones;
  5894 
  5895 * slightly changed interfaces for oracles: admit many per theory, named
  5896 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5897 
  5898 * print_goals: optional output of const types (set show_consts and
  5899 show_types);
  5900 
  5901 * improved output of warnings (###) and errors (***);
  5902 
  5903 * subgoal_tac displays a warning if the new subgoal has type variables;
  5904 
  5905 * removed old README and Makefiles;
  5906 
  5907 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5908 
  5909 * removed obsolete init_pps and init_database;
  5910 
  5911 * deleted the obsolete tactical STATE, which was declared by
  5912     fun STATE tacfun st = tacfun st st;
  5913 
  5914 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5915 (which abbreviates $HOME);
  5916 
  5917 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5918 use isatool fixseq to adapt your ML programs (this works for fully
  5919 qualified references to the Sequence structure only!);
  5920 
  5921 * use_thy no longer requires writable current directory; it always
  5922 reloads .ML *and* .thy file, if either one is out of date;
  5923 
  5924 
  5925 *** Classical Reasoner ***
  5926 
  5927 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5928 tactics that use classical reasoning to simplify a subgoal without
  5929 splitting it into several subgoals;
  5930 
  5931 * Safe_tac: like safe_tac but uses the default claset;
  5932 
  5933 
  5934 *** Simplifier ***
  5935 
  5936 * added simplification meta rules:
  5937     (asm_)(full_)simplify: simpset -> thm -> thm;
  5938 
  5939 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5940 logics (again);
  5941 
  5942 * added prems argument to simplification procedures;
  5943 
  5944 * HOL, FOL, ZF: added infix function `addsplits':
  5945   instead of `<simpset> setloop (split_tac <thms>)'
  5946   you can simply write `<simpset> addsplits <thms>'
  5947 
  5948 
  5949 *** Syntax ***
  5950 
  5951 * TYPE('a) syntax for type reflection terms;
  5952 
  5953 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5954 
  5955 * pretty printer: changed order of mixfix annotation preference (again!);
  5956 
  5957 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5958 
  5959 
  5960 *** HOL ***
  5961 
  5962 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5963   with `addloop' of the simplifier to faciliate case splitting in premises.
  5964 
  5965 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5966 
  5967 * HOL/Auth: new protocol proofs including some for the Internet
  5968   protocol TLS;
  5969 
  5970 * HOL/Map: new theory of `maps' a la VDM;
  5971 
  5972 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5973 cancelling out common nat summands from =, <, <= (in)equalities, or
  5974 differences; simplification procedures nat_cancel_factor for
  5975 cancelling common factor from =, <, <= (in)equalities over natural
  5976 sums; nat_cancel contains both kinds of procedures, it is installed by
  5977 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5978 
  5979 * HOL/simplifier: terms of the form
  5980   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5981   are rewritten to
  5982   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5983   and those of the form
  5984   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5985   are rewritten to
  5986   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5987 
  5988 * HOL/datatype
  5989   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5990 
  5991   P(t_case f1 ... fn x) =
  5992      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5993         ...
  5994        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5995      )
  5996 
  5997   and a theorem `split_t_case_asm' of the form
  5998 
  5999   P(t_case f1 ... fn x) =
  6000     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  6001         ...
  6002        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  6003      )
  6004   which can be added to a simpset via `addsplits'. The existing theorems
  6005   expand_list_case and expand_option_case have been renamed to
  6006   split_list_case and split_option_case.
  6007 
  6008 * HOL/Arithmetic:
  6009   - `pred n' is automatically converted to `n-1'.
  6010     Users are strongly encouraged not to use `pred' any longer,
  6011     because it will disappear altogether at some point.
  6012   - Users are strongly encouraged to write "0 < n" rather than
  6013     "n ~= 0". Theorems and proof tools have been modified towards this
  6014     `standard'.
  6015 
  6016 * HOL/Lists:
  6017   the function "set_of_list" has been renamed "set" (and its theorems too);
  6018   the function "nth" now takes its arguments in the reverse order and
  6019   has acquired the infix notation "!" as in "xs!n".
  6020 
  6021 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  6022 
  6023 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  6024   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  6025 
  6026 * HOL/record: extensible records with schematic structural subtyping
  6027 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  6028 still lacks various theorems and concrete record syntax;
  6029 
  6030 
  6031 *** HOLCF ***
  6032 
  6033 * removed "axioms" and "generated by" sections;
  6034 
  6035 * replaced "ops" section by extended "consts" section, which is capable of
  6036   handling the continuous function space "->" directly;
  6037 
  6038 * domain package:
  6039   . proves theorems immediately and stores them in the theory,
  6040   . creates hierachical name space,
  6041   . now uses normal mixfix annotations (instead of cinfix...),
  6042   . minor changes to some names and values (for consistency),
  6043   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  6044   . separator between mutual domain defs: changed "," to "and",
  6045   . improved handling of sort constraints;  now they have to
  6046     appear on the left-hand side of the equations only;
  6047 
  6048 * fixed LAM <x,y,zs>.b syntax;
  6049 
  6050 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  6051 adm (%x. P (t x)), where P is chainfinite and t continuous;
  6052 
  6053 
  6054 *** FOL and ZF ***
  6055 
  6056 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6057   with `addloop' of the simplifier to faciliate case splitting in premises.
  6058 
  6059 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6060 in HOL, they strip ALL and --> from proved theorems;
  6061 
  6062 
  6063 
  6064 New in Isabelle94-8 (May 1997)
  6065 ------------------------------
  6066 
  6067 *** General Changes ***
  6068 
  6069 * new utilities to build / run / maintain Isabelle etc. (in parts
  6070 still somewhat experimental); old Makefiles etc. still functional;
  6071 
  6072 * new 'Isabelle System Manual';
  6073 
  6074 * INSTALL text, together with ./configure and ./build scripts;
  6075 
  6076 * reimplemented type inference for greater efficiency, better error
  6077 messages and clean internal interface;
  6078 
  6079 * prlim command for dealing with lots of subgoals (an easier way of
  6080 setting goals_limit);
  6081 
  6082 
  6083 *** Syntax ***
  6084 
  6085 * supports alternative (named) syntax tables (parser and pretty
  6086 printer); internal interface is provided by add_modesyntax(_i);
  6087 
  6088 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6089 be used in conjunction with the Isabelle symbol font; uses the
  6090 "symbols" syntax table;
  6091 
  6092 * added token_translation interface (may translate name tokens in
  6093 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6094 the current print_mode); IMPORTANT: user print translation functions
  6095 are responsible for marking newly introduced bounds
  6096 (Syntax.mark_boundT);
  6097 
  6098 * token translations for modes "xterm" and "xterm_color" that display
  6099 names in bold, underline etc. or colors (which requires a color
  6100 version of xterm);
  6101 
  6102 * infixes may now be declared with names independent of their syntax;
  6103 
  6104 * added typed_print_translation (like print_translation, but may
  6105 access type of constant);
  6106 
  6107 
  6108 *** Classical Reasoner ***
  6109 
  6110 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6111 some limitations.  Blast_tac...
  6112   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6113   + ignores elimination rules that don't have the correct format
  6114         (the conclusion MUST be a formula variable)
  6115   + ignores types, which can make HOL proofs fail
  6116   + rules must not require higher-order unification, e.g. apply_type in ZF
  6117     [message "Function Var's argument not a bound variable" relates to this]
  6118   + its proof strategy is more general but can actually be slower
  6119 
  6120 * substitution with equality assumptions no longer permutes other
  6121 assumptions;
  6122 
  6123 * minor changes in semantics of addafter (now called addaltern); renamed
  6124 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6125 (and access functions for it);
  6126 
  6127 * improved combination of classical reasoner and simplifier:
  6128   + functions for handling clasimpsets
  6129   + improvement of addss: now the simplifier is called _after_ the
  6130     safe steps.
  6131   + safe variant of addss called addSss: uses safe simplifications
  6132     _during_ the safe steps. It is more complete as it allows multiple
  6133     instantiations of unknowns (e.g. with slow_tac).
  6134 
  6135 *** Simplifier ***
  6136 
  6137 * added interface for simplification procedures (functions that
  6138 produce *proven* rewrite rules on the fly, depending on current
  6139 redex);
  6140 
  6141 * ordering on terms as parameter (used for ordered rewriting);
  6142 
  6143 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6144 
  6145 * the solver is now split into a safe and an unsafe part.
  6146 This should be invisible for the normal user, except that the
  6147 functions setsolver and addsolver have been renamed to setSolver and
  6148 addSolver; added safe_asm_full_simp_tac;
  6149 
  6150 
  6151 *** HOL ***
  6152 
  6153 * a generic induction tactic `induct_tac' which works for all datatypes and
  6154 also for type `nat';
  6155 
  6156 * a generic case distinction tactic `exhaust_tac' which works for all
  6157 datatypes and also for type `nat';
  6158 
  6159 * each datatype comes with a function `size';
  6160 
  6161 * patterns in case expressions allow tuple patterns as arguments to
  6162 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6163 
  6164 * primrec now also works with type nat;
  6165 
  6166 * recdef: a new declaration form, allows general recursive functions to be
  6167 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6168 
  6169 * the constant for negation has been renamed from "not" to "Not" to
  6170 harmonize with FOL, ZF, LK, etc.;
  6171 
  6172 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6173 infinite lists;
  6174 
  6175 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6176 
  6177 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6178 problems in commutative rings, using axiomatic type classes for + and *;
  6179 
  6180 * more examples in HOL/MiniML and HOL/Auth;
  6181 
  6182 * more default rewrite rules for quantifiers, union/intersection;
  6183 
  6184 * a new constant `arbitrary == @x.False';
  6185 
  6186 * HOLCF/IOA replaces old HOL/IOA;
  6187 
  6188 * HOLCF changes: derived all rules and arities
  6189   + axiomatic type classes instead of classes
  6190   + typedef instead of faking type definitions
  6191   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6192   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6193   + eliminated the types void, one, tr
  6194   + use unit lift and bool lift (with translations) instead of one and tr
  6195   + eliminated blift from Lift3.thy (use Def instead of blift)
  6196   all eliminated rules are derived as theorems --> no visible changes ;
  6197 
  6198 
  6199 *** ZF ***
  6200 
  6201 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6202 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6203 as ZF_cs addSIs [equalityI];
  6204 
  6205 
  6206 
  6207 New in Isabelle94-7 (November 96)
  6208 ---------------------------------
  6209 
  6210 * allowing negative levels (as offsets) in prlev and choplev;
  6211 
  6212 * super-linear speedup for large simplifications;
  6213 
  6214 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6215 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6216 FAIL); can suppress it using the command Delsimps (ex_simps @
  6217 all_simps); De Morgan laws are also now included, by default;
  6218 
  6219 * improved printing of ==>  :  ~:
  6220 
  6221 * new object-logic "Sequents" adds linear logic, while replacing LK
  6222 and Modal (thanks to Sara Kalvala);
  6223 
  6224 * HOL/Auth: correctness proofs for authentication protocols;
  6225 
  6226 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6227 examples on HOL/Auth);
  6228 
  6229 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6230 the rewriter and classical reasoner simultaneously;
  6231 
  6232 * function uresult no longer returns theorems in "standard" format;
  6233 regain previous version by: val uresult = standard o uresult;
  6234 
  6235 
  6236 
  6237 New in Isabelle94-6
  6238 -------------------
  6239 
  6240 * oracles -- these establish an interface between Isabelle and trusted
  6241 external reasoners, which may deliver results as theorems;
  6242 
  6243 * proof objects (in particular record all uses of oracles);
  6244 
  6245 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6246 
  6247 * "constdefs" section in theory files;
  6248 
  6249 * "primrec" section (HOL) no longer requires names;
  6250 
  6251 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6252 
  6253 
  6254 
  6255 New in Isabelle94-5
  6256 -------------------
  6257 
  6258 * reduced space requirements;
  6259 
  6260 * automatic HTML generation from theories;
  6261 
  6262 * theory files no longer require "..." (quotes) around most