NEWS
author nipkow
Wed Jun 24 09:41:14 2009 +0200 (2009-06-24)
changeset 31790 05c92381363c
parent 31784 bd3486c57ba3
child 31804 627d142fce19
permissions -rw-r--r--
corrected and unified thm names
     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 
    66 *** ML ***
    67 
    68 * Eliminated old Attrib.add_attributes, Method.add_methods and related
    69 cominators for "args".  INCOMPATIBILITY, need to use simplified
    70 Attrib/Method.setup introduced in Isabelle2009.
    71 
    72 
    73 *** System ***
    74 
    75 * Discontinued support for Poly/ML 4.x versions.
    76 
    77 * Removed "compress" option from isabelle-process and isabelle usedir;
    78 this is always enabled.
    79 
    80 
    81 
    82 New in Isabelle2009 (April 2009)
    83 --------------------------------
    84 
    85 *** General ***
    86 
    87 * Simplified main Isabelle executables, with less surprises on
    88 case-insensitive file-systems (such as Mac OS).
    89 
    90   - The main Isabelle tool wrapper is now called "isabelle" instead of
    91     "isatool."
    92 
    93   - The former "isabelle" alias for "isabelle-process" has been
    94     removed (should rarely occur to regular users).
    95 
    96   - The former "isabelle-interface" and its alias "Isabelle" have been
    97     removed (interfaces are now regular Isabelle tools).
    98 
    99 Within scripts and make files, the Isabelle environment variables
   100 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
   101 respectively.  (The latter are still available as legacy feature.)
   102 
   103 The old isabelle-interface wrapper could react in confusing ways if
   104 the interface was uninstalled or changed otherwise.  Individual
   105 interface tool configuration is now more explicit, see also the
   106 Isabelle system manual.  In particular, Proof General is now available
   107 via "isabelle emacs".
   108 
   109 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
   110 purge installed copies of Isabelle executables and re-run "isabelle
   111 install -p ...", or use symlinks.
   112 
   113 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
   114 old ~/isabelle, which was slightly non-standard and apt to cause
   115 surprises on case-insensitive file-systems (such as Mac OS).
   116 
   117 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
   118 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
   119 care is required when using older releases of Isabelle.  Note that
   120 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
   121 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
   122 
   123 * Proofs of fully specified statements are run in parallel on
   124 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
   125 a regular 4-core machine, if the initial heap space is made reasonably
   126 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
   127 
   128 * The main reference manuals ("isar-ref", "implementation", and
   129 "system") have been updated and extended.  Formally checked references
   130 as hyperlinks are now available uniformly.
   131 
   132 
   133 *** Pure ***
   134 
   135 * Complete re-implementation of locales.  INCOMPATIBILITY in several
   136 respects.  The most important changes are listed below.  See the
   137 Tutorial on Locales ("locales" manual) for details.
   138 
   139 - In locale expressions, instantiation replaces renaming.  Parameters
   140 must be declared in a for clause.  To aid compatibility with previous
   141 parameter inheritance, in locale declarations, parameters that are not
   142 'touched' (instantiation position "_" or omitted) are implicitly added
   143 with their syntax at the beginning of the for clause.
   144 
   145 - Syntax from abbreviations and definitions in locales is available in
   146 locale expressions and context elements.  The latter is particularly
   147 useful in locale declarations.
   148 
   149 - More flexible mechanisms to qualify names generated by locale
   150 expressions.  Qualifiers (prefixes) may be specified in locale
   151 expressions, and can be marked as mandatory (syntax: "name!:") or
   152 optional (syntax "name?:").  The default depends for plain "name:"
   153 depends on the situation where a locale expression is used: in
   154 commands 'locale' and 'sublocale' prefixes are optional, in
   155 'interpretation' and 'interpret' prefixes are mandatory.  The old
   156 implicit qualifiers derived from the parameter names of a locale are
   157 no longer generated.
   158 
   159 - Command "sublocale l < e" replaces "interpretation l < e".  The
   160 instantiation clause in "interpretation" and "interpret" (square
   161 brackets) is no longer available.  Use locale expressions.
   162 
   163 - When converting proof scripts, mandatory qualifiers in
   164 'interpretation' and 'interpret' should be retained by default, even
   165 if this is an INCOMPATIBILITY compared to former behavior.  In the
   166 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   167 in locale expressions range over a single locale instance only.
   168 
   169 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   170 In existing theorem specifications replace the includes element by the
   171 respective context elements of the included locale, omitting those
   172 that are already present in the theorem specification.  Multiple
   173 assume elements of a locale should be replaced by a single one
   174 involving the locale predicate.  In the proof body, declarations (most
   175 notably theorems) may be regained by interpreting the respective
   176 locales in the proof context as required (command "interpret").
   177 
   178 If using "includes" in replacement of a target solely because the
   179 parameter types in the theorem are not as general as in the target,
   180 consider declaring a new locale with additional type constraints on
   181 the parameters (context element "constrains").
   182 
   183 - Discontinued "locale (open)".  INCOMPATIBILITY.
   184 
   185 - Locale interpretation commands no longer attempt to simplify goal.
   186 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   187 methods intro_locales and unfold_locales to clarify.
   188 
   189 - Locale interpretation commands no longer accept interpretation
   190 attributes.  INCOMPATIBILITY.
   191 
   192 * Class declaration: so-called "base sort" must not be given in import
   193 list any longer, but is inferred from the specification.  Particularly
   194 in HOL, write
   195 
   196     class foo = ...
   197 
   198 instead of
   199 
   200     class foo = type + ...
   201 
   202 * Class target: global versions of theorems stemming do not carry a
   203 parameter prefix any longer.  INCOMPATIBILITY.
   204 
   205 * Class 'instance' command no longer accepts attached definitions.
   206 INCOMPATIBILITY, use proper 'instantiation' target instead.
   207 
   208 * Recovered hiding of consts, which was accidentally broken in
   209 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   210 makes c inaccessible; consider using ``hide (open) const c'' instead.
   211 
   212 * Slightly more coherent Pure syntax, with updated documentation in
   213 isar-ref manual.  Removed locales meta_term_syntax and
   214 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   215 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   216 directly in regular applications.
   217 
   218 * There is a new syntactic category "float_const" for signed decimal
   219 fractions (e.g. 123.45 or -123.45).
   220 
   221 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   222 interface with 'setup' command instead.
   223 
   224 * Command 'local_setup' is similar to 'setup', but operates on a local
   225 theory context.
   226 
   227 * The 'axiomatization' command now only works within a global theory
   228 context.  INCOMPATIBILITY.
   229 
   230 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   231 hypotheses.  Sorts required in the course of reasoning need to be
   232 covered by the constraints in the initial statement, completed by the
   233 type instance information of the background theory.  Non-trivial sort
   234 hypotheses, which rarely occur in practice, may be specified via
   235 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   236 
   237   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   238 
   239 The result contains an implicit sort hypotheses as before --
   240 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   241 normalization.
   242 
   243 * Generalized Isar history, with support for linear undo, direct state
   244 addressing etc.
   245 
   246 * Changed defaults for unify configuration options:
   247 
   248   unify_trace_bound = 50 (formerly 25)
   249   unify_search_bound = 60 (formerly 30)
   250 
   251 * Different bookkeeping for code equations (INCOMPATIBILITY):
   252 
   253   a) On theory merge, the last set of code equations for a particular
   254      constant is taken (in accordance with the policy applied by other
   255      parts of the code generator framework).
   256 
   257   b) Code equations stemming from explicit declarations (e.g. code
   258      attribute) gain priority over default code equations stemming
   259      from definition, primrec, fun etc.
   260 
   261 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   262 
   263 * Unified theorem tables for both code generators.  Thus [code
   264 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   265 
   266 * Command 'find_consts' searches for constants based on type and name
   267 patterns, e.g.
   268 
   269     find_consts "_ => bool"
   270 
   271 By default, matching is against subtypes, but it may be restricted to
   272 the whole type.  Searching by name is possible.  Multiple queries are
   273 conjunctive and queries may be negated by prefixing them with a
   274 hyphen:
   275 
   276     find_consts strict: "_ => bool" name: "Int" -"int => int"
   277 
   278 * New 'find_theorems' criterion "solves" matches theorems that
   279 directly solve the current goal (modulo higher-order unification).
   280 
   281 * Auto solve feature for main theorem statements: whenever a new goal
   282 is stated, "find_theorems solves" is called; any theorems that could
   283 solve the lemma directly are listed as part of the goal state.
   284 Cf. associated options in Proof General Isabelle settings menu,
   285 enabled by default, with reasonable timeout for pathological cases of
   286 higher-order unification.
   287 
   288 
   289 *** Document preparation ***
   290 
   291 * Antiquotation @{lemma} now imitates a regular terminal proof,
   292 demanding keyword 'by' and supporting the full method expression
   293 syntax just like the Isar command 'by'.
   294 
   295 
   296 *** HOL ***
   297 
   298 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   299 points Main and Complex_Main remain as before.
   300 
   301 * Logic image HOL-Plain provides a minimal HOL with the most important
   302 tools available (inductive, datatype, primrec, ...).  This facilitates
   303 experimentation and tool development.  Note that user applications
   304 (and library theories) should never refer to anything below theory
   305 Main, as before.
   306 
   307 * Logic image HOL-Main stops at theory Main, and thus facilitates
   308 experimentation due to shorter build times.
   309 
   310 * Logic image HOL-NSA contains theories of nonstandard analysis which
   311 were previously part of former HOL-Complex.  Entry point Hyperreal
   312 remains valid, but theories formerly using Complex_Main should now use
   313 new entry point Hypercomplex.
   314 
   315 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   316 Posix processes.  Avoids potentially expensive forking of the ML
   317 process.  New thread-based implementation also works on non-Unix
   318 platforms (Cygwin).  Provers are no longer hardwired, but defined
   319 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   320 commands are covered in the isar-ref manual.
   321 
   322 * Wrapper scripts for remote SystemOnTPTP service allows to use
   323 sledgehammer without local ATP installation (Vampire etc.). Other
   324 provers may be included via suitable ML wrappers, see also
   325 src/HOL/ATP_Linkup.thy.
   326 
   327 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   328 menu.
   329 
   330 * The metis method no longer fails because the theorem is too trivial
   331 (contains the empty clause).
   332 
   333 * The metis method now fails in the usual manner, rather than raising
   334 an exception, if it determines that it cannot prove the theorem.
   335 
   336 * Method "coherent" implements a prover for coherent logic (see also
   337 src/Tools/coherent.ML).
   338 
   339 * Constants "undefined" and "default" replace "arbitrary".  Usually
   340 "undefined" is the right choice to replace "arbitrary", though
   341 logically there is no difference.  INCOMPATIBILITY.
   342 
   343 * Command "value" now integrates different evaluation mechanisms.  The
   344 result of the first successful evaluation mechanism is printed.  In
   345 square brackets a particular named evaluation mechanisms may be
   346 specified (currently, [SML], [code] or [nbe]).  See further
   347 src/HOL/ex/Eval_Examples.thy.
   348 
   349 * Normalization by evaluation now allows non-leftlinear equations.
   350 Declare with attribute [code nbe].
   351 
   352 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   353 as the structured Isar versions "cases" and "induct", cf. the
   354 corresponding "cases" and "induct" attributes.  Mutual induction rules
   355 are now presented as a list of individual projections
   356 (e.g. foo_bar.inducts for types foo and bar); the old format with
   357 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   358 rare situations a different rule is selected --- notably nested tuple
   359 elimination instead of former prod.exhaust: use explicit (case_tac t
   360 rule: prod.exhaust) here.
   361 
   362 * Attributes "cases", "induct", "coinduct" support "del" option.
   363 
   364 * Removed fact "case_split_thm", which duplicates "case_split".
   365 
   366 * The option datatype has been moved to a new theory Option.  Renamed
   367 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   368 
   369 * New predicate "strict_mono" classifies strict functions on partial
   370 orders.  With strict functions on linear orders, reasoning about
   371 (in)equalities is facilitated by theorems "strict_mono_eq",
   372 "strict_mono_less_eq" and "strict_mono_less".
   373 
   374 * Some set operations are now proper qualified constants with
   375 authentic syntax.  INCOMPATIBILITY:
   376 
   377     op Int ~>   Set.Int
   378     op Un ~>    Set.Un
   379     INTER ~>    Set.INTER
   380     UNION ~>    Set.UNION
   381     Inter ~>    Set.Inter
   382     Union ~>    Set.Union
   383     {} ~>       Set.empty
   384     UNIV ~>     Set.UNIV
   385 
   386 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   387 theory Set.
   388 
   389 * Auxiliary class "itself" has disappeared -- classes without any
   390 parameter are treated as expected by the 'class' command.
   391 
   392 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   393 
   394 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   395 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   396 
   397 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   398 method "approximation".  It proves formulas on real values by using
   399 interval arithmetic.  In the formulas are also the transcendental
   400 functions sin, cos, tan, atan, ln, exp and the constant pi are
   401 allowed. For examples see
   402 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   403 
   404 * Theory "Reflection" now resides in HOL/Library.
   405 
   406 * Entry point to Word library now simply named "Word".
   407 INCOMPATIBILITY.
   408 
   409 * Made source layout more coherent with logical distribution
   410 structure:
   411 
   412     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   413     src/HOL/Library/Code_Message.thy ~> src/HOL/
   414     src/HOL/Library/GCD.thy ~> src/HOL/
   415     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   416     src/HOL/Library/Parity.thy ~> src/HOL/
   417     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   418     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   419     src/HOL/Real/Lubs.thy ~> src/HOL/
   420     src/HOL/Real/PReal.thy ~> src/HOL/
   421     src/HOL/Real/Rational.thy ~> src/HOL/
   422     src/HOL/Real/RComplete.thy ~> src/HOL/
   423     src/HOL/Real/RealDef.thy ~> src/HOL/
   424     src/HOL/Real/RealPow.thy ~> src/HOL/
   425     src/HOL/Real/Real.thy ~> src/HOL/
   426     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   427     src/HOL/Complex/Complex.thy ~> src/HOL/
   428     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   429     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   430     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   431     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   432     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   433     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   434     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   435     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   436     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   437     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   438     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   439     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   440     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   441     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   442     src/HOL/Real/Float ~> src/HOL/Library/
   443     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   444     src/HOL/Real/RealVector.thy ~> src/HOL/
   445 
   446     src/HOL/arith_data.ML ~> src/HOL/Tools
   447     src/HOL/hologic.ML ~> src/HOL/Tools
   448     src/HOL/simpdata.ML ~> src/HOL/Tools
   449     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   450     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   451     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   452     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   453     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   454     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   455     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   456 
   457     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   458     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   459     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   460     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   461     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   462     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   463 
   464 * If methods "eval" and "evaluation" encounter a structured proof
   465 state with !!/==>, only the conclusion is evaluated to True (if
   466 possible), avoiding strange error messages.
   467 
   468 * Method "sizechange" automates termination proofs using (a
   469 modification of) the size-change principle.  Requires SAT solver.  See
   470 src/HOL/ex/Termination.thy for examples.
   471 
   472 * Simplifier: simproc for let expressions now unfolds if bound
   473 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   474 
   475 * Method "arith": Linear arithmetic now ignores all inequalities when
   476 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   477 
   478 * New attribute "arith" for facts that should always be used
   479 automatically by arithmetic. It is intended to be used locally in
   480 proofs, e.g.
   481 
   482   assumes [arith]: "x > 0"
   483 
   484 Global usage is discouraged because of possible performance impact.
   485 
   486 * New classes "top" and "bot" with corresponding operations "top" and
   487 "bot" in theory Orderings; instantiation of class "complete_lattice"
   488 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   489 
   490 * Changed definition lemma "less_fun_def" in order to provide an
   491 instance for preorders on functions; use lemma "less_le" instead.
   492 INCOMPATIBILITY.
   493 
   494 * Theory Orderings: class "wellorder" moved here, with explicit
   495 induction rule "less_induct" as assumption.  For instantiation of
   496 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   497 INCOMPATIBILITY.
   498 
   499 * Theory Orderings: added class "preorder" as superclass of "order".
   500 INCOMPATIBILITY: Instantiation proofs for order, linorder
   501 etc. slightly changed.  Some theorems named order_class.* now named
   502 preorder_class.*.
   503 
   504 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   505 "diag" to "Id_on".
   506 
   507 * Theory Finite_Set: added a new fold combinator of type
   508 
   509   ('a => 'b => 'b) => 'b => 'a set => 'b
   510 
   511 Occasionally this is more convenient than the old fold combinator
   512 which is now defined in terms of the new one and renamed to
   513 fold_image.
   514 
   515 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   516 and "ring_simps" have been replaced by "algebra_simps" (which can be
   517 extended with further lemmas!).  At the moment both still exist but
   518 the former will disappear at some point.
   519 
   520 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   521 class recpower.  Type-specific simp rules for various recpower types
   522 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   523 
   524 rat_power_0    -> power_0
   525 rat_power_Suc  -> power_Suc
   526 realpow_0      -> power_0
   527 realpow_Suc    -> power_Suc
   528 complexpow_0   -> power_0
   529 complexpow_Suc -> power_Suc
   530 power_poly_0   -> power_0
   531 power_poly_Suc -> power_Suc
   532 
   533 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   534 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   535 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   536 of lemmas from Divides has been generalized from nat to class
   537 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   538 renames resulting from duplicate elimination:
   539 
   540     dvd_def_mod ~>          dvd_eq_mod_eq_0
   541     zero_dvd_iff ~>         dvd_0_left_iff
   542     dvd_0 ~>                dvd_0_right
   543     DIVISION_BY_ZERO_DIV ~> div_by_0
   544     DIVISION_BY_ZERO_MOD ~> mod_by_0
   545     mult_div ~>             div_mult_self2_is_id
   546     mult_mod ~>             mod_mult_self2_is_0
   547 
   548 * Theory IntDiv: removed many lemmas that are instances of class-based
   549 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   550 rename old lemmas as follows:
   551 
   552 dvd_diff               -> nat_dvd_diff
   553 dvd_zminus_iff         -> dvd_minus_iff
   554 mod_add1_eq            -> mod_add_eq
   555 mod_mult1_eq           -> mod_mult_right_eq
   556 mod_mult1_eq'          -> mod_mult_left_eq
   557 mod_mult_distrib_mod   -> mod_mult_eq
   558 nat_mod_add_left_eq    -> mod_add_left_eq
   559 nat_mod_add_right_eq   -> mod_add_right_eq
   560 nat_mod_div_trivial    -> mod_div_trivial
   561 nat_mod_mod_trivial    -> mod_mod_trivial
   562 zdiv_zadd_self1        -> div_add_self1
   563 zdiv_zadd_self2        -> div_add_self2
   564 zdiv_zmult_self1       -> div_mult_self2_is_id
   565 zdiv_zmult_self2       -> div_mult_self1_is_id
   566 zdvd_triv_left         -> dvd_triv_left
   567 zdvd_triv_right        -> dvd_triv_right
   568 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   569 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   570 zmod_zadd_left_eq      -> mod_add_left_eq
   571 zmod_zadd_right_eq     -> mod_add_right_eq
   572 zmod_zadd_self1        -> mod_add_self1
   573 zmod_zadd_self2        -> mod_add_self2
   574 zmod_zadd1_eq          -> mod_add_eq
   575 zmod_zdiff1_eq         -> mod_diff_eq
   576 zmod_zdvd_zmod         -> mod_mod_cancel
   577 zmod_zmod_cancel       -> mod_mod_cancel
   578 zmod_zmult_self1       -> mod_mult_self2_is_0
   579 zmod_zmult_self2       -> mod_mult_self1_is_0
   580 zmod_1                 -> mod_by_1
   581 zdiv_1                 -> div_by_1
   582 zdvd_abs1              -> abs_dvd_iff
   583 zdvd_abs2              -> dvd_abs_iff
   584 zdvd_refl              -> dvd_refl
   585 zdvd_trans             -> dvd_trans
   586 zdvd_zadd              -> dvd_add
   587 zdvd_zdiff             -> dvd_diff
   588 zdvd_zminus_iff        -> dvd_minus_iff
   589 zdvd_zminus2_iff       -> minus_dvd_iff
   590 zdvd_zmultD            -> dvd_mult_right
   591 zdvd_zmultD2           -> dvd_mult_left
   592 zdvd_zmult_mono        -> mult_dvd_mono
   593 zdvd_0_right           -> dvd_0_right
   594 zdvd_0_left            -> dvd_0_left_iff
   595 zdvd_1_left            -> one_dvd
   596 zminus_dvd_iff         -> minus_dvd_iff
   597 
   598 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   599 
   600 * The real numbers offer decimal input syntax: 12.34 is translated
   601 into 1234/10^2. This translation is not reversed upon output.
   602 
   603 * Theory Library/Polynomial defines an abstract type 'a poly of
   604 univariate polynomials with coefficients of type 'a.  In addition to
   605 the standard ring operations, it also supports div and mod.  Code
   606 generation is also supported, using list-style constructors.
   607 
   608 * Theory Library/Inner_Product defines a class of real_inner for real
   609 inner product spaces, with an overloaded operation inner :: 'a => 'a
   610 => real.  Class real_inner is a subclass of real_normed_vector from
   611 theory RealVector.
   612 
   613 * Theory Library/Product_Vector provides instances for the product
   614 type 'a * 'b of several classes from RealVector and Inner_Product.
   615 Definitions of addition, subtraction, scalar multiplication, norms,
   616 and inner products are included.
   617 
   618 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   619 addition to the field operations, numerals and case syntax are also
   620 supported.
   621 
   622 * Theory Library/Diagonalize provides constructive version of Cantor's
   623 first diagonalization argument.
   624 
   625 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   626 zlcm (for int); carried together from various gcd/lcm developements in
   627 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   628 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   629 may recover tupled syntax as follows:
   630 
   631     hide (open) const gcd
   632     abbreviation gcd where
   633       "gcd == (%(a, b). GCD.gcd a b)"
   634     notation (output)
   635       GCD.gcd ("gcd '(_, _')")
   636 
   637 The same works for lcm, zgcd, zlcm.
   638 
   639 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   640 instantiations for algebraic structures.  Removed some duplicate
   641 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   642 
   643 * ML antiquotation @{code} takes a constant as argument and generates
   644 corresponding code in background and inserts name of the corresponding
   645 resulting ML value/function/datatype constructor binding in place.
   646 All occurrences of @{code} with a single ML block are generated
   647 simultaneously.  Provides a generic and safe interface for
   648 instrumentalizing code generation.  See
   649 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   650 In future you ought to refrain from ad-hoc compiling generated SML
   651 code on the ML toplevel.  Note that (for technical reasons) @{code}
   652 cannot refer to constants for which user-defined serializations are
   653 set.  Refer to the corresponding ML counterpart directly in that
   654 cases.
   655 
   656 * Command 'rep_datatype': instead of theorem names the command now
   657 takes a list of terms denoting the constructors of the type to be
   658 represented as datatype.  The characteristic theorems have to be
   659 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   660 have disappeared in favour of existing ones:
   661 
   662     unit_induct                 ~> unit.induct
   663     prod_induct                 ~> prod.induct
   664     sum_induct                  ~> sum.induct
   665     Suc_Suc_eq                  ~> nat.inject
   666     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   667 
   668 
   669 *** HOL-Algebra ***
   670 
   671 * New locales for orders and lattices where the equivalence relation
   672 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   673 locales use a record structure with field eq for the equivalence.
   674 
   675 * New theory of factorial domains.
   676 
   677 * Units_l_inv and Units_r_inv are now simp rules by default.
   678 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   679 and/or r_inv will now also require deletion of these lemmas.
   680 
   681 * Renamed the following theorems, INCOMPATIBILITY:
   682 
   683 UpperD ~> Upper_memD
   684 LowerD ~> Lower_memD
   685 least_carrier ~> least_closed
   686 greatest_carrier ~> greatest_closed
   687 greatest_Lower_above ~> greatest_Lower_below
   688 one_zero ~> carrier_one_zero
   689 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   690 
   691 
   692 *** HOL-Nominal ***
   693 
   694 * Nominal datatypes can now contain type-variables.
   695 
   696 * Commands 'nominal_inductive' and 'equivariance' work with local
   697 theory targets.
   698 
   699 * Nominal primrec can now works with local theory targets and its
   700 specification syntax now conforms to the general format as seen in
   701 'inductive' etc.
   702 
   703 * Method "perm_simp" honours the standard simplifier attributes
   704 (no_asm), (no_asm_use) etc.
   705 
   706 * The new predicate #* is defined like freshness, except that on the
   707 left hand side can be a set or list of atoms.
   708 
   709 * Experimental command 'nominal_inductive2' derives strong induction
   710 principles for inductive definitions.  In contrast to
   711 'nominal_inductive', which can only deal with a fixed number of
   712 binders, it can deal with arbitrary expressions standing for sets of
   713 atoms to be avoided.  The only inductive definition we have at the
   714 moment that needs this generalisation is the typing rule for Lets in
   715 the algorithm W:
   716 
   717  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   718  -----------------------------------------------------------------
   719          Gamma |- Let x be t1 in t2 : T2
   720 
   721 In this rule one wants to avoid all the binders that are introduced by
   722 "close Gamma T1".  We are looking for other examples where this
   723 feature might be useful.  Please let us know.
   724 
   725 
   726 *** HOLCF ***
   727 
   728 * Reimplemented the simplification procedure for proving continuity
   729 subgoals.  The new simproc is extensible; users can declare additional
   730 continuity introduction rules with the attribute [cont2cont].
   731 
   732 * The continuity simproc now uses a different introduction rule for
   733 solving continuity subgoals on terms with lambda abstractions.  In
   734 some rare cases the new simproc may fail to solve subgoals that the
   735 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   736 Potential INCOMPATIBILITY.
   737 
   738 * Command 'fixrec': specification syntax now conforms to the general
   739 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   740 examples.  INCOMPATIBILITY.
   741 
   742 
   743 *** ZF ***
   744 
   745 * Proof of Zorn's Lemma for partial orders.
   746 
   747 
   748 *** ML ***
   749 
   750 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   751 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   752 depends on multithreading, so timouts will not work before Poly/ML
   753 5.2.1!
   754 
   755 * High-level support for concurrent ML programming, see
   756 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   757 particularly convenient to organize independent functional
   758 computations.  The concept of "synchronized variables" provides a
   759 higher-order interface for components with shared state, avoiding the
   760 delicate details of mutexes and condition variables.  (Requires
   761 Poly/ML 5.2.1 or later.)
   762 
   763 * ML bindings produced via Isar commands are stored within the Isar
   764 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   765 become thread-safe and work with undo as expected (concerning
   766 top-level bindings, not side-effects on global references).
   767 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   768 compiler at runtime; really global bindings need to be given outside a
   769 theory.  (Requires Poly/ML 5.2 or later.)
   770 
   771 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   772 context.  Top-level ML bindings are stored within the proof context in
   773 a purely sequential fashion, disregarding the nested proof structure.
   774 ML bindings introduced by 'ML_prf' are discarded at the end of the
   775 proof.  (Requires Poly/ML 5.2 or later.)
   776 
   777 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   778 and Method.setup, as well as Isar commands 'attribute_setup' and
   779 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   780 existing code accordingly, or use plain 'setup' together with old
   781 Method.add_method.
   782 
   783 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   784 to 'a -> thm, while results are always tagged with an authentic oracle
   785 name.  The Isar command 'oracle' is now polymorphic, no argument type
   786 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   787 accordingly.  Note that extra performance may be gained by producing
   788 the cterm carefully, avoiding slow Thm.cterm_of.
   789 
   790 * Simplified interface for defining document antiquotations via
   791 ThyOutput.antiquotation, ThyOutput.output, and optionally
   792 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   793 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   794 examples.
   795 
   796 * More systematic treatment of long names, abstract name bindings, and
   797 name space operations.  Basic operations on qualified names have been
   798 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   799 Long_Name.append.  Old type bstring has been mostly replaced by
   800 abstract type binding (see structure Binding), which supports precise
   801 qualification by packages and local theory targets, as well as proper
   802 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   803 bstring values into Binding.name, or better pass through abstract
   804 bindings everywhere.  See further src/Pure/General/long_name.ML,
   805 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   806 
   807 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   808 LocalTheory.note etc.) now refer to the *full* internal name, not the
   809 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   810 
   811 * Disposed old type and term read functions (Sign.read_def_typ,
   812 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   813 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   814 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   815 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   816 resort for legacy applications.
   817 
   818 * Disposed old declarations, tactics, tactic combinators that refer to
   819 the simpset or claset of an implicit theory (such as Addsimps,
   820 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   821 embedded ML text, or local_simpset_of with a proper context passed as
   822 explicit runtime argument.
   823 
   824 * Rules and tactics that read instantiations (read_instantiate,
   825 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   826 context, which is required for parsing and type-checking.  Moreover,
   827 the variables are specified as plain indexnames, not string encodings
   828 thereof.  INCOMPATIBILITY.
   829 
   830 * Generic Toplevel.add_hook interface allows to analyze the result of
   831 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   832 for theorem dependency output of transactions resulting in a new
   833 theory state.
   834 
   835 * ML antiquotations: block-structured compilation context indicated by
   836 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   837 
   838   @{binding name}                         - basic name binding
   839   @{let ?pat = term}                      - term abbreviation (HO matching)
   840   @{note name = fact}                     - fact abbreviation
   841   @{thm fact}                             - singleton fact (with attributes)
   842   @{thms fact}                            - general fact (with attributes)
   843   @{lemma prop by method}                 - singleton goal
   844   @{lemma prop by meth1 meth2}            - singleton goal
   845   @{lemma prop1 ... propN by method}      - general goal
   846   @{lemma prop1 ... propN by meth1 meth2} - general goal
   847   @{lemma (open) ...}                     - open derivation
   848 
   849 
   850 *** System ***
   851 
   852 * The Isabelle "emacs" tool provides a specific interface to invoke
   853 Proof General / Emacs, with more explicit failure if that is not
   854 installed (the old isabelle-interface script silently falls back on
   855 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   856 installation location of the Proof General distribution.
   857 
   858 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   859 the Isabelle process into a JVM/Scala application.  See
   860 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   861 process wrapper has been discontinued.)
   862 
   863 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   864 
   865 * Various status messages (with exact source position information) are
   866 emitted, if proper markup print mode is enabled.  This allows
   867 user-interface components to provide detailed feedback on internal
   868 prover operations.
   869 
   870 
   871 
   872 New in Isabelle2008 (June 2008)
   873 -------------------------------
   874 
   875 *** General ***
   876 
   877 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   878 and updated, with formally checked references as hyperlinks.
   879 
   880 * Theory loader: use_thy (and similar operations) no longer set the
   881 implicit ML context, which was occasionally hard to predict and in
   882 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   883 provides a proper context already.
   884 
   885 * Theory loader: old-style ML proof scripts being *attached* to a thy
   886 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   887 'use' within a theory file will do the job.
   888 
   889 * Name space merge now observes canonical order, i.e. the second space
   890 is inserted into the first one, while existing entries in the first
   891 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   892 swap theory imports.
   893 
   894 * Syntax: symbol \<chi> is now considered a letter.  Potential
   895 INCOMPATIBILITY in identifier syntax etc.
   896 
   897 * Outer syntax: string tokens no longer admit escaped white space,
   898 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   899 white space without escapes.
   900 
   901 * Outer syntax: string tokens may contain arbitrary character codes
   902 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   903 "foo_bar".
   904 
   905 
   906 *** Pure ***
   907 
   908 * Context-dependent token translations.  Default setup reverts locally
   909 fixed variables, and adds hilite markup for undeclared frees.
   910 
   911 * Unused theorems can be found using the new command 'unused_thms'.
   912 There are three ways of invoking it:
   913 
   914 (1) unused_thms
   915      Only finds unused theorems in the current theory.
   916 
   917 (2) unused_thms thy_1 ... thy_n -
   918      Finds unused theorems in the current theory and all of its ancestors,
   919      excluding the theories thy_1 ... thy_n and all of their ancestors.
   920 
   921 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   922      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   923      their ancestors, excluding the theories thy_1 ... thy_n and all of
   924      their ancestors.
   925 
   926 In order to increase the readability of the list produced by
   927 unused_thms, theorems that have been created by a particular instance
   928 of a theory command such as 'inductive' or 'function' are considered
   929 to belong to the same "group", meaning that if at least one theorem in
   930 this group is used, the other theorems in the same group are no longer
   931 reported as unused.  Moreover, if all theorems in the group are
   932 unused, only one theorem in the group is displayed.
   933 
   934 Note that proof objects have to be switched on in order for
   935 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   936 usually the case when using Proof General with the default settings).
   937 
   938 * Authentic naming of facts disallows ad-hoc overwriting of previous
   939 theorems within the same name space.  INCOMPATIBILITY, need to remove
   940 duplicate fact bindings, or even accidental fact duplications.  Note
   941 that tools may maintain dynamically scoped facts systematically, using
   942 PureThy.add_thms_dynamic.
   943 
   944 * Command 'hide' now allows to hide from "fact" name space as well.
   945 
   946 * Eliminated destructive theorem database, simpset, claset, and
   947 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   948 update of theories within ML code.
   949 
   950 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   951 INCOMPATIBILITY, object-logics depending on former Pure require
   952 additional setup PureThy.old_appl_syntax_setup; object-logics
   953 depending on former CPure need to refer to Pure.
   954 
   955 * Commands 'use' and 'ML' are now purely functional, operating on
   956 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   957 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   958 INCOMPATIBILITY.
   959 
   960 * Command 'setup': discontinued implicit version with ML reference.
   961 
   962 * Instantiation target allows for simultaneous specification of class
   963 instance operations together with an instantiation proof.
   964 Type-checking phase allows to refer to class operations uniformly.
   965 See src/HOL/Complex/Complex.thy for an Isar example and
   966 src/HOL/Library/Eval.thy for an ML example.
   967 
   968 * Indexing of literal facts: be more serious about including only
   969 facts from the visible specification/proof context, but not the
   970 background context (locale etc.).  Affects `prop` notation and method
   971 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   972 situations.
   973 
   974 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   975 "(open)" option, which used to expose internal bound variables to the
   976 proof text.
   977 
   978 * Isar statements: removed obsolete case "rule_context".
   979 INCOMPATIBILITY, better use explicit fixes/assumes.
   980 
   981 * Locale proofs: default proof step now includes 'unfold_locales';
   982 hence 'proof' without argument may be used to unfold locale
   983 predicates.
   984 
   985 
   986 *** Document preparation ***
   987 
   988 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   989 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   990 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   991 spot); renamed link color from "darkblue" to "linkcolor" (default
   992 value unchanged, can be redefined via \definecolor); no longer sets
   993 "a4paper" option (unnecessary or even intrusive).
   994 
   995 * Antiquotation @{lemma A method} proves proposition A by the given
   996 method (either a method name or a method name plus (optional) method
   997 arguments in parentheses) and prints A just like @{prop A}.
   998 
   999 
  1000 *** HOL ***
  1001 
  1002 * New primrec package.  Specification syntax conforms in style to
  1003 definition/function/....  No separate induction rule is provided.  The
  1004 "primrec" command distinguishes old-style and new-style specifications
  1005 by syntax.  The former primrec package is now named OldPrimrecPackage.
  1006 When adjusting theories, beware: constants stemming from new-style
  1007 primrec specifications have authentic syntax.
  1008 
  1009 * Metis prover is now an order of magnitude faster, and also works
  1010 with multithreading.
  1011 
  1012 * Metis: the maximum number of clauses that can be produced from a
  1013 theorem is now given by the attribute max_clauses.  Theorems that
  1014 exceed this number are ignored, with a warning printed.
  1015 
  1016 * Sledgehammer no longer produces structured proofs by default. To
  1017 enable, declare [[sledgehammer_full = true]].  Attributes
  1018 reconstruction_modulus, reconstruction_sorts renamed
  1019 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
  1020 
  1021 * Method "induct_scheme" derives user-specified induction rules
  1022 from well-founded induction and completeness of patterns. This factors
  1023 out some operations that are done internally by the function package
  1024 and makes them available separately.  See
  1025 src/HOL/ex/Induction_Scheme.thy for examples.
  1026 
  1027 * More flexible generation of measure functions for termination
  1028 proofs: Measure functions can be declared by proving a rule of the
  1029 form "is_measure f" and giving it the [measure_function] attribute.
  1030 The "is_measure" predicate is logically meaningless (always true), and
  1031 just guides the heuristic.  To find suitable measure functions, the
  1032 termination prover sets up the goal "is_measure ?f" of the appropriate
  1033 type and generates all solutions by prolog-style backwards proof using
  1034 the declared rules.
  1035 
  1036 This setup also deals with rules like 
  1037 
  1038   "is_measure f ==> is_measure (list_size f)"
  1039 
  1040 which accommodates nested datatypes that recurse through lists.
  1041 Similar rules are predeclared for products and option types.
  1042 
  1043 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
  1044 
  1045   INCOMPATIBILITIES:
  1046 
  1047   - Definitions of overloaded constants on sets have to be replaced by
  1048     definitions on => and bool.
  1049 
  1050   - Some definitions of overloaded operators on sets can now be proved
  1051     using the definitions of the operators on => and bool.  Therefore,
  1052     the following theorems have been renamed:
  1053 
  1054       subset_def   -> subset_eq
  1055       psubset_def  -> psubset_eq
  1056       set_diff_def -> set_diff_eq
  1057       Compl_def    -> Compl_eq
  1058       Sup_set_def  -> Sup_set_eq
  1059       Inf_set_def  -> Inf_set_eq
  1060       sup_set_def  -> sup_set_eq
  1061       inf_set_def  -> inf_set_eq
  1062 
  1063   - Due to the incompleteness of the HO unification algorithm, some
  1064     rules such as subst may require manual instantiation, if some of
  1065     the unknowns in the rule is a set.
  1066 
  1067   - Higher order unification and forward proofs:
  1068     The proof pattern
  1069 
  1070       have "P (S::'a set)" <...>
  1071       then have "EX S. P S" ..
  1072 
  1073     no longer works (due to the incompleteness of the HO unification
  1074     algorithm) and must be replaced by the pattern
  1075 
  1076       have "EX S. P S"
  1077       proof
  1078         show "P S" <...>
  1079       qed
  1080 
  1081   - Calculational reasoning with subst (or similar rules):
  1082     The proof pattern
  1083 
  1084       have "P (S::'a set)" <...>
  1085       also have "S = T" <...>
  1086       finally have "P T" .
  1087 
  1088     no longer works (for similar reasons as the previous example) and
  1089     must be replaced by something like
  1090 
  1091       have "P (S::'a set)" <...>
  1092       moreover have "S = T" <...>
  1093       ultimately have "P T" by simp
  1094 
  1095   - Tactics or packages written in ML code:
  1096     Code performing pattern matching on types via
  1097 
  1098       Type ("set", [T]) => ...
  1099 
  1100     must be rewritten. Moreover, functions like strip_type or
  1101     binder_types no longer return the right value when applied to a
  1102     type of the form
  1103 
  1104       T1 => ... => Tn => U => bool
  1105 
  1106     rather than
  1107 
  1108       T1 => ... => Tn => U set
  1109 
  1110 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1111 Wellfounded_Relations to theory Wellfounded.
  1112 
  1113 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1114 
  1115 * Class finite no longer treats UNIV as class parameter.  Use class
  1116 enum from theory Library/Enum instead to achieve a similar effect.
  1117 INCOMPATIBILITY.
  1118 
  1119 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1120 and "Cons".  INCOMPATIBILITY.
  1121 
  1122 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1123 Potential INCOMPATIBILITY.
  1124 
  1125 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1126 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1127 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1128 
  1129 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1130 the same name in theory Orderings:
  1131 
  1132   less_trans
  1133   less_linear
  1134   le_imp_less_or_eq
  1135   le_less_trans
  1136   less_le_trans
  1137   less_not_sym
  1138   less_asym
  1139 
  1140 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1141 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1142 and different variable names.
  1143 
  1144 * Library/Option_ord.thy: Canonical order on option type.
  1145 
  1146 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1147 finite maps.
  1148 
  1149 * Library/Countable.thy: Type class for countable types.
  1150 
  1151 * Theory Int: The representation of numerals has changed.  The infix
  1152 operator BIT and the bit datatype with constructors B0 and B1 have
  1153 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1154 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1155 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1156 accordingly.
  1157 
  1158 * Theory Nat: definition of <= and < on natural numbers no longer
  1159 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1160 le_def and less_def have disappeared.  Consider lemmas not_less
  1161 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1162 
  1163 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1164 (whose purpose mainly is for various fold_set functionals) have been
  1165 abandoned in favor of the existing algebraic classes
  1166 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1167 lower_semilattice (resp. upper_semilattice) and linorder.
  1168 INCOMPATIBILITY.
  1169 
  1170 * Theory Transitive_Closure: induct and cases rules now declare proper
  1171 case_names ("base" and "step").  INCOMPATIBILITY.
  1172 
  1173 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1174 lattices.  The form set-specific version is available as
  1175 Inductive.lfp_ordinal_induct_set.
  1176 
  1177 * Renamed theorems "power.simps" to "power_int.simps".
  1178 INCOMPATIBILITY.
  1179 
  1180 * Class semiring_div provides basic abstract properties of semirings
  1181 with division and modulo operations.  Subsumes former class dvd_mod.
  1182 
  1183 * Merged theories IntDef, Numeral and IntArith into unified theory
  1184 Int.  INCOMPATIBILITY.
  1185 
  1186 * Theory Library/Code_Index: type "index" now represents natural
  1187 numbers rather than integers.  INCOMPATIBILITY.
  1188 
  1189 * New class "uminus" with operation "uminus" (split of from class
  1190 "minus" which now only has operation "minus", binary).
  1191 INCOMPATIBILITY.
  1192 
  1193 * Constants "card", "internal_split", "option_map" now with authentic
  1194 syntax.  INCOMPATIBILITY.
  1195 
  1196 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1197 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1198 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1199 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1200 Sup_set_def, le_def, less_def, option_map_def now with object
  1201 equality.  INCOMPATIBILITY.
  1202 
  1203 * Records. Removed K_record, and replaced it by pure lambda term
  1204 %x. c. The simplifier setup is now more robust against eta expansion.
  1205 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1206 
  1207 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1208 
  1209 * Library/ListVector: new theory of arithmetic vector operations.
  1210 
  1211 * Library/Order_Relation: new theory of various orderings as sets of
  1212 pairs.  Defines preorders, partial orders, linear orders and
  1213 well-orders on sets and on types.
  1214 
  1215 
  1216 *** ZF ***
  1217 
  1218 * Renamed some theories to allow to loading both ZF and HOL in the
  1219 same session:
  1220 
  1221   Datatype  -> Datatype_ZF
  1222   Inductive -> Inductive_ZF
  1223   Int       -> Int_ZF
  1224   IntDiv    -> IntDiv_ZF
  1225   Nat       -> Nat_ZF
  1226   List      -> List_ZF
  1227   Main      -> Main_ZF
  1228 
  1229 INCOMPATIBILITY: ZF theories that import individual theories below
  1230 Main might need to be adapted.  Regular theory Main is still
  1231 available, as trivial extension of Main_ZF.
  1232 
  1233 
  1234 *** ML ***
  1235 
  1236 * ML within Isar: antiquotation @{const name} or @{const
  1237 name(typargs)} produces statically-checked Const term.
  1238 
  1239 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1240 (of the same name).  Removed obsolete print command.
  1241 
  1242 * Removed obsolete "use_legacy_bindings" function.
  1243 
  1244 * The ``print mode'' is now a thread-local value derived from a global
  1245 template (the former print_mode reference), thus access becomes
  1246 non-critical.  The global print_mode reference is for session
  1247 management only; user-code should use print_mode_value,
  1248 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1249 
  1250 * Functions system/system_out provide a robust way to invoke external
  1251 shell commands, with propagation of interrupts (requires Poly/ML
  1252 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1253 
  1254 
  1255 *** System ***
  1256 
  1257 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1258 in accordance with Proof General 3.7, which prefers GNU emacs.
  1259 
  1260 * isatool tty runs Isabelle process with plain tty interaction;
  1261 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1262 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1263 
  1264 * isatool browser now works with Cygwin as well, using general
  1265 "javapath" function defined in Isabelle process environment.
  1266 
  1267 * YXML notation provides a simple and efficient alternative to
  1268 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1269 isatool yxml as described in the Isabelle system manual.
  1270 
  1271 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1272 provides general wrapper for managing an Isabelle process in a robust
  1273 fashion, with ``cooked'' output from stdin/stderr.
  1274 
  1275 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1276 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1277 
  1278 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1279 way of changing the user's settings is via
  1280 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1281 script.
  1282 
  1283 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1284 cores of the underlying machine, which is a good starting point for
  1285 optimal performance tuning.  The corresponding usedir option -M allows
  1286 "max" as an alias for "0".  WARNING: does not work on certain versions
  1287 of Mac OS (with Poly/ML 5.1).
  1288 
  1289 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1290 adverse effect of Isabelle flooding interactive front-ends (notably
  1291 ProofGeneral / XEmacs).
  1292 
  1293 
  1294 
  1295 New in Isabelle2007 (November 2007)
  1296 -----------------------------------
  1297 
  1298 *** General ***
  1299 
  1300 * More uniform information about legacy features, notably a
  1301 warning/error of "Legacy feature: ...", depending on the state of the
  1302 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1303 legacy features will disappear eventually.
  1304 
  1305 * Theory syntax: the header format ``theory A = B + C:'' has been
  1306 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1307 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1308 
  1309 * Theory syntax: the old non-Isar theory file format has been
  1310 discontinued altogether.  Note that ML proof scripts may still be used
  1311 with Isar theories; migration is usually quite simple with the ML
  1312 function use_legacy_bindings.  INCOMPATIBILITY.
  1313 
  1314 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1315 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1316 quotes.
  1317 
  1318 * Theory loader: be more serious about observing the static theory
  1319 header specifications (including optional directories), but not the
  1320 accidental file locations of previously successful loads.  The strict
  1321 update policy of former update_thy is now already performed by
  1322 use_thy, so the former has been removed; use_thys updates several
  1323 theories simultaneously, just as 'imports' within a theory header
  1324 specification, but without merging the results.  Potential
  1325 INCOMPATIBILITY: may need to refine theory headers and commands
  1326 ROOT.ML which depend on load order.
  1327 
  1328 * Theory loader: optional support for content-based file
  1329 identification, instead of the traditional scheme of full physical
  1330 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1331 (cf. the system manual).  The new scheme allows to work with
  1332 non-finished theories in persistent session images, such that source
  1333 files may be moved later on without requiring reloads.
  1334 
  1335 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1336 file (with the same base name as the theory) are considered a legacy
  1337 feature, which will disappear eventually. Even now, the theory loader
  1338 no longer maintains dependencies on such files.
  1339 
  1340 * Syntax: the scope for resolving ambiguities via type-inference is
  1341 now limited to individual terms, instead of whole simultaneous
  1342 specifications as before. This greatly reduces the complexity of the
  1343 syntax module and improves flexibility by separating parsing and
  1344 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1345 'fixes' etc.) are required in rare situations.
  1346 
  1347 * Syntax: constants introduced by new-style packages ('definition',
  1348 'abbreviation' etc.) are passed through the syntax module in
  1349 ``authentic mode''. This means that associated mixfix annotations
  1350 really stick to such constants, independently of potential name space
  1351 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1352 trees are represented slightly differently, may need to adapt syntax
  1353 translations accordingly. Use CONST marker in 'translations' and
  1354 @{const_syntax} antiquotation in 'parse_translation' etc.
  1355 
  1356 * Legacy goal package: reduced interface to the bare minimum required
  1357 to keep existing proof scripts running.  Most other user-level
  1358 functions are now part of the OldGoals structure, which is *not* open
  1359 by default (consider isatool expandshort before open OldGoals).
  1360 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1361 these tend to cause confusion about the actual goal (!) context being
  1362 used here, which is not necessarily the same as the_context().
  1363 
  1364 * Command 'find_theorems': supports "*" wild-card in "name:"
  1365 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1366 support a specific search form (see ProofGeneral/CHANGES).
  1367 
  1368 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1369 by default, which means that "prems" (and also "fixed variables") are
  1370 suppressed from proof state output.  Note that the ProofGeneral
  1371 settings mechanism allows to change and save options persistently, but
  1372 older versions of Isabelle will fail to start up if a negative prems
  1373 limit is imposed.
  1374 
  1375 * Local theory targets may be specified by non-nested blocks of
  1376 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1377 contain definitions, theorems etc., including any derived mechanism
  1378 that has been implemented on top of these primitives.  This concept
  1379 generalizes the existing ``theorem (in ...)'' towards more versatility
  1380 and scalability.
  1381 
  1382 * Proof General interface: proper undo of final 'end' command;
  1383 discontinued Isabelle/classic mode (ML proof scripts).
  1384 
  1385 
  1386 *** Document preparation ***
  1387 
  1388 * Added antiquotation @{theory name} which prints the given name,
  1389 after checking that it refers to a valid ancestor theory in the
  1390 current context.
  1391 
  1392 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1393 check the given source text as ML type/structure, printing verbatim.
  1394 
  1395 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1396 "c args == rhs" given in the current context.  (Any number of
  1397 arguments may be given on the LHS.)
  1398 
  1399 
  1400 *** Pure ***
  1401 
  1402 * The 'class' package offers a combination of axclass and locale to
  1403 achieve Haskell-like type classes in Isabelle.  Definitions and
  1404 theorems within a class context produce both relative results (with
  1405 implicit parameters according to the locale context), and polymorphic
  1406 constants with qualified polymorphism (according to the class
  1407 context).  Within the body context of a 'class' target, a separate
  1408 syntax layer ("user space type system") takes care of converting
  1409 between global polymorphic consts and internal locale representation.
  1410 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1411 "isatool doc classes" provides a tutorial.
  1412 
  1413 * Generic code generator framework allows to generate executable
  1414 code for ML and Haskell (including Isabelle classes).  A short usage
  1415 sketch:
  1416 
  1417     internal compilation:
  1418         export_code <list of constants (term syntax)> in SML
  1419     writing SML code to a file:
  1420         export_code <list of constants (term syntax)> in SML <filename>
  1421     writing OCaml code to a file:
  1422         export_code <list of constants (term syntax)> in OCaml <filename>
  1423     writing Haskell code to a bunch of files:
  1424         export_code <list of constants (term syntax)> in Haskell <filename>
  1425 
  1426     evaluating closed propositions to True/False using code generation:
  1427         method ``eval''
  1428 
  1429 Reasonable default setup of framework in HOL.
  1430 
  1431 Theorem attributs for selecting and transforming function equations theorems:
  1432 
  1433     [code fun]:        select a theorem as function equation for a specific constant
  1434     [code fun del]:    deselect a theorem as function equation for a specific constant
  1435     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1436     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1437 
  1438 User-defined serializations (target in {SML, OCaml, Haskell}):
  1439 
  1440     code_const <and-list of constants (term syntax)>
  1441       {(target) <and-list of const target syntax>}+
  1442 
  1443     code_type <and-list of type constructors>
  1444       {(target) <and-list of type target syntax>}+
  1445 
  1446     code_instance <and-list of instances>
  1447       {(target)}+
  1448         where instance ::= <type constructor> :: <class>
  1449 
  1450     code_class <and_list of classes>
  1451       {(target) <and-list of class target syntax>}+
  1452         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1453 
  1454 code_instance and code_class only are effective to target Haskell.
  1455 
  1456 For example usage see src/HOL/ex/Codegenerator.thy and
  1457 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1458 generation from Isabelle/HOL theories is available via "isatool doc
  1459 codegen".
  1460 
  1461 * Code generator: consts in 'consts_code' Isar commands are now
  1462 referred to by usual term syntax (including optional type
  1463 annotations).
  1464 
  1465 * Command 'no_translations' removes translation rules from theory
  1466 syntax.
  1467 
  1468 * Overloaded definitions are now actually checked for acyclic
  1469 dependencies.  The overloading scheme is slightly more general than
  1470 that of Haskell98, although Isabelle does not demand an exact
  1471 correspondence to type class and instance declarations.
  1472 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1473 exotic versions of overloading -- at the discretion of the user!
  1474 
  1475 Polymorphic constants are represented via type arguments, i.e. the
  1476 instantiation that matches an instance against the most general
  1477 declaration given in the signature.  For example, with the declaration
  1478 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1479 as c(nat).  Overloading is essentially simultaneous structural
  1480 recursion over such type arguments.  Incomplete specification patterns
  1481 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1482 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1483 Command 'print_theory' outputs the normalized system of recursive
  1484 equations, see section "definitions".
  1485 
  1486 * Configuration options are maintained within the theory or proof
  1487 context (with name and type bool/int/string), providing a very simple
  1488 interface to a poor-man's version of general context data.  Tools may
  1489 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1490 these values using Config.get etc.  Users may change options via an
  1491 associated attribute of the same name.  This form of context
  1492 declaration works particularly well with commands 'declare' or
  1493 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1494 very easy to avoid global references, which would not observe Isar
  1495 toplevel undo/redo and fail to work with multithreading.
  1496 
  1497 Various global ML references of Pure and HOL have been turned into
  1498 configuration options:
  1499 
  1500   Unify.search_bound		unify_search_bound
  1501   Unify.trace_bound		unify_trace_bound
  1502   Unify.trace_simp		unify_trace_simp
  1503   Unify.trace_types		unify_trace_types
  1504   Simplifier.simp_depth_limit	simp_depth_limit
  1505   Blast.depth_limit		blast_depth_limit
  1506   DatatypeProp.dtK		datatype_distinctness_limit
  1507   fast_arith_neq_limit  	fast_arith_neq_limit
  1508   fast_arith_split_limit	fast_arith_split_limit
  1509 
  1510 * Named collections of theorems may be easily installed as context
  1511 data using the functor NamedThmsFun (see also
  1512 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1513 attributes; there is also a toplevel print command.  This facility is
  1514 just a common case of general context data, which is the preferred way
  1515 for anything more complex than just a list of facts in canonical
  1516 order.
  1517 
  1518 * Isar: command 'declaration' augments a local theory by generic
  1519 declaration functions written in ML.  This enables arbitrary content
  1520 being added to the context, depending on a morphism that tells the
  1521 difference of the original declaration context wrt. the application
  1522 context encountered later on.
  1523 
  1524 * Isar: proper interfaces for simplification procedures.  Command
  1525 'simproc_setup' declares named simprocs (with match patterns, and body
  1526 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1527 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1528 
  1529 * Isar: an extra pair of brackets around attribute declarations
  1530 abbreviates a theorem reference involving an internal dummy fact,
  1531 which will be ignored later --- only the effect of the attribute on
  1532 the background context will persist.  This form of in-place
  1533 declarations is particularly useful with commands like 'declare' and
  1534 'using', for example ``have A using [[simproc a]] by simp''.
  1535 
  1536 * Isar: method "assumption" (and implicit closing of subproofs) now
  1537 takes simple non-atomic goal assumptions into account: after applying
  1538 an assumption as a rule the resulting subgoals are solved by atomic
  1539 assumption steps.  This is particularly useful to finish 'obtain'
  1540 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1541 without referring to the original premise "!!x. P x ==> thesis" in the
  1542 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1543 more permissive.
  1544 
  1545 * Isar: implicit use of prems from the Isar proof context is
  1546 considered a legacy feature.  Common applications like ``have A .''
  1547 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1548 referencing facts explicitly here improves readability and
  1549 maintainability of proof texts.
  1550 
  1551 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1552 the obtained context from the course of reasoning!  For example:
  1553 
  1554   assume "EX x y. A x & B y"   -- "any previous fact"
  1555   then guess x and y by clarify
  1556 
  1557 This technique is potentially adventurous, depending on the facts and
  1558 proof tools being involved here.
  1559 
  1560 * Isar: known facts from the proof context may be specified as literal
  1561 propositions, using ASCII back-quote syntax.  This works wherever
  1562 named facts used to be allowed so far, in proof commands, proof
  1563 methods, attributes etc.  Literal facts are retrieved from the context
  1564 according to unification of type and term parameters.  For example,
  1565 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1566 theorems in the current context, then these are valid literal facts:
  1567 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1568 
  1569 There is also a proof method "fact" which does the same composition
  1570 for explicit goal states, e.g. the following proof texts coincide with
  1571 certain special cases of literal facts:
  1572 
  1573   have "A" by fact                 ==  note `A`
  1574   have "A ==> B" by fact           ==  note `A ==> B`
  1575   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1576   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1577 
  1578 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1579 outer syntax.  Thus symbolic identifiers may be used without
  1580 additional white space in declarations like this: ``assume *: A''.
  1581 
  1582 * Isar: 'print_facts' prints all local facts of the current context,
  1583 both named and unnamed ones.
  1584 
  1585 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1586 
  1587   def x == "t" and y == "u"
  1588 
  1589 * Isar: added command 'unfolding', which is structurally similar to
  1590 'using', but affects both the goal state and facts by unfolding given
  1591 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1592 'unfolded' attribute may be replaced by first-class proof text.
  1593 
  1594 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1595 and command 'unfolding' now all support object-level equalities
  1596 (potentially conditional).  The underlying notion of rewrite rule is
  1597 analogous to the 'rule_format' attribute, but *not* that of the
  1598 Simplifier (which is usually more generous).
  1599 
  1600 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1601 premises of a theorem by n. Useful in conjunction with drule.
  1602 
  1603 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1604 method expression within a sandbox consisting of the first N
  1605 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1606 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1607 simplifies all new goals that emerge from applying rule foo to the
  1608 originally first one.
  1609 
  1610 * Isar: schematic goals are no longer restricted to higher-order
  1611 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1612 expected.
  1613 
  1614 * Isar: the conclusion of a long theorem statement is now either
  1615 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1616 (essentially a disjunction of cases with local parameters and
  1617 assumptions).  The latter allows to express general elimination rules
  1618 adequately; in this notation common elimination rules look like this:
  1619 
  1620   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1621     assumes "EX x. P x"
  1622     obtains x where "P x"
  1623 
  1624   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1625     assumes "A & B"
  1626     obtains A and B
  1627 
  1628   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1629     assumes "A | B"
  1630     obtains
  1631       A
  1632     | B
  1633 
  1634 The subsequent classical rules even refer to the formal "thesis"
  1635 explicitly:
  1636 
  1637   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1638     obtains "~ thesis"
  1639 
  1640   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1641     obtains "thesis ==> something"
  1642 
  1643 The actual proof of an 'obtains' statement is analogous to that of the
  1644 Isar proof element 'obtain', only that there may be several cases.
  1645 Optional case names may be specified in parentheses; these will be
  1646 available both in the present proof and as annotations in the
  1647 resulting rule, for later use with the 'cases' method (cf. attribute
  1648 case_names).
  1649 
  1650 * Isar: the assumptions of a long theorem statement are available as
  1651 "assms" fact in the proof context.  This is more appropriate than the
  1652 (historical) "prems", which refers to all assumptions of the current
  1653 context, including those from the target locale, proof body etc.
  1654 
  1655 * Isar: 'print_statement' prints theorems from the current theory or
  1656 proof context in long statement form, according to the syntax of a
  1657 top-level lemma.
  1658 
  1659 * Isar: 'obtain' takes an optional case name for the local context
  1660 introduction rule (default "that").
  1661 
  1662 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1663 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1664 to occur.
  1665 
  1666 * Pure: syntax "CONST name" produces a fully internalized constant
  1667 according to the current context.  This is particularly useful for
  1668 syntax translations that should refer to internal constant
  1669 representations independently of name spaces.
  1670 
  1671 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1672 instead of "FOO ". This allows multiple binder declarations to coexist
  1673 in the same context.  INCOMPATIBILITY.
  1674 
  1675 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1676 primitive that also works in a locale context (both for constants and
  1677 fixed variables). Type declaration and internal syntactic representation
  1678 of given constants retrieved from the context. Likewise, the
  1679 'no_notation' command allows to remove given syntax annotations from the
  1680 current context.
  1681 
  1682 * Isar/locales: new derived specification elements 'axiomatization',
  1683 'definition', 'abbreviation', which support type-inference, admit
  1684 object-level specifications (equality, equivalence).  See also the
  1685 isar-ref manual.  Examples:
  1686 
  1687   axiomatization
  1688     eq  (infix "===" 50) where
  1689     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1690 
  1691   definition "f x y = x + y + 1"
  1692   definition g where "g x = f x x"
  1693 
  1694   abbreviation
  1695     neq  (infix "=!=" 50) where
  1696     "x =!= y == ~ (x === y)"
  1697 
  1698 These specifications may be also used in a locale context.  Then the
  1699 constants being introduced depend on certain fixed parameters, and the
  1700 constant name is qualified by the locale base name.  An internal
  1701 abbreviation takes care for convenient input and output, making the
  1702 parameters implicit and using the original short name.  See also
  1703 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1704 entities from a monomorphic theory.
  1705 
  1706 Presently, abbreviations are only available 'in' a target locale, but
  1707 not inherited by general import expressions.  Also note that
  1708 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1709 'translations' in common applications.  The "no_abbrevs" print mode
  1710 prevents folding of abbreviations in term output.
  1711 
  1712 Concrete syntax is attached to specified constants in internal form,
  1713 independently of name spaces.  The parse tree representation is
  1714 slightly different -- use 'notation' instead of raw 'syntax', and
  1715 'translations' with explicit "CONST" markup to accommodate this.
  1716 
  1717 * Pure/Isar: unified syntax for new-style specification mechanisms
  1718 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1719 full type inference and dummy patterns ("_").  For example:
  1720 
  1721   definition "K x _ = x"
  1722 
  1723   inductive conj for A B
  1724   where "A ==> B ==> conj A B"
  1725 
  1726 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1727 the current context.  Print mode "no_abbrevs" prevents inversion of
  1728 abbreviations on output.
  1729 
  1730 * Isar/locales: improved parameter handling: use of locales "var" and
  1731 "struct" no longer necessary; - parameter renamings are no longer
  1732 required to be injective.  For example, this allows to define
  1733 endomorphisms as locale endom = homom mult mult h.
  1734 
  1735 * Isar/locales: changed the way locales with predicates are defined.
  1736 Instead of accumulating the specification, the imported expression is
  1737 now an interpretation.  INCOMPATIBILITY: different normal form of
  1738 locale expressions.  In particular, in interpretations of locales with
  1739 predicates, goals repesenting already interpreted fragments are not
  1740 removed automatically.  Use methods `intro_locales' and
  1741 `unfold_locales'; see below.
  1742 
  1743 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1744 provide backward reasoning on locales predicates.  The methods are
  1745 aware of interpretations and discharge corresponding goals.
  1746 `intro_locales' is less aggressive then `unfold_locales' and does not
  1747 unfold predicates to assumptions.
  1748 
  1749 * Isar/locales: the order in which locale fragments are accumulated
  1750 has changed.  This enables to override declarations from fragments due
  1751 to interpretations -- for example, unwanted simp rules.
  1752 
  1753 * Isar/locales: interpretation in theories and proof contexts has been
  1754 extended.  One may now specify (and prove) equations, which are
  1755 unfolded in interpreted theorems.  This is useful for replacing
  1756 defined concepts (constants depending on locale parameters) by
  1757 concepts already existing in the target context.  Example:
  1758 
  1759   interpretation partial_order ["op <= :: [int, int] => bool"]
  1760     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1761 
  1762 Typically, the constant `partial_order.less' is created by a
  1763 definition specification element in the context of locale
  1764 partial_order.
  1765 
  1766 * Method "induct": improved internal context management to support
  1767 local fixes and defines on-the-fly. Thus explicit meta-level
  1768 connectives !!  and ==> are rarely required anymore in inductive goals
  1769 (using object-logic connectives for this purpose has been long
  1770 obsolete anyway). Common proof patterns are explained in
  1771 src/HOL/Induct/Common_Patterns.thy, see also
  1772 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1773 examples.
  1774 
  1775 * Method "induct": improved handling of simultaneous goals. Instead of
  1776 introducing object-level conjunction, the statement is now split into
  1777 several conclusions, while the corresponding symbolic cases are nested
  1778 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1779 see src/HOL/Induct/Common_Patterns.thy, for example.
  1780 
  1781 * Method "induct": mutual induction rules are now specified as a list
  1782 of rule sharing the same induction cases. HOL packages usually provide
  1783 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1784 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1785 mutual induction rules differently, i.e. like this:
  1786 
  1787   (induct rule: foo_bar.inducts)
  1788   (induct set: foo bar)
  1789   (induct pred: foo bar)
  1790   (induct type: foo bar)
  1791 
  1792 The ML function ProjectRule.projections turns old-style rules into the
  1793 new format.
  1794 
  1795 * Method "coinduct": dual of induction, see
  1796 src/HOL/Library/Coinductive_List.thy for various examples.
  1797 
  1798 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1799 considered a legacy feature.
  1800 
  1801 * Attribute "symmetric" produces result with standardized schematic
  1802 variables (index 0).  Potential INCOMPATIBILITY.
  1803 
  1804 * Simplifier: by default the simplifier trace only shows top level
  1805 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1806 default. Thus there is less danger of being flooded by the trace. The
  1807 trace indicates where parts have been suppressed.
  1808   
  1809 * Provers/classical: removed obsolete classical version of elim_format
  1810 attribute; classical elim/dest rules are now treated uniformly when
  1811 manipulating the claset.
  1812 
  1813 * Provers/classical: stricter checks to ensure that supplied intro,
  1814 dest and elim rules are well-formed; dest and elim rules must have at
  1815 least one premise.
  1816 
  1817 * Provers/classical: attributes dest/elim/intro take an optional
  1818 weight argument for the rule (just as the Pure versions).  Weights are
  1819 ignored by automated tools, but determine the search order of single
  1820 rule steps.
  1821 
  1822 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1823 where the body does not mention the bound variable.  Note that dummy
  1824 patterns implicitly depend on their context of bounds, which makes
  1825 "{_. _}" match any set comprehension as expected.  Potential
  1826 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1827 constant "_idtdummy" in the binding position.
  1828 
  1829 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1830 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1831 for example "A -> B" => "Pi A (%_. B)".
  1832 
  1833 * Pure: 'class_deps' command visualizes the subclass relation, using
  1834 the graph browser tool.
  1835 
  1836 * Pure: 'print_theory' now suppresses certain internal declarations by
  1837 default; use '!' option for full details.
  1838 
  1839 
  1840 *** HOL ***
  1841 
  1842 * Method "metis" proves goals by applying the Metis general-purpose
  1843 resolution prover (see also http://gilith.com/software/metis/).
  1844 Examples are in the directory MetisExamples.  WARNING: the
  1845 Isabelle/HOL-Metis integration does not yet work properly with
  1846 multi-threading.
  1847   
  1848 * Command 'sledgehammer' invokes external automatic theorem provers as
  1849 background processes.  It generates calls to the "metis" method if
  1850 successful. These can be pasted into the proof.  Users do not have to
  1851 wait for the automatic provers to return.  WARNING: does not really
  1852 work with multi-threading.
  1853 
  1854 * New "auto_quickcheck" feature tests outermost goal statements for
  1855 potential counter-examples.  Controlled by ML references
  1856 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1857 5000 milliseconds).  Fails silently if statements is outside of
  1858 executable fragment, or any other codgenerator problem occurs.
  1859 
  1860 * New constant "undefined" with axiom "undefined x = undefined".
  1861 
  1862 * Added class "HOL.eq", allowing for code generation with polymorphic
  1863 equality.
  1864 
  1865 * Some renaming of class constants due to canonical name prefixing in
  1866 the new 'class' package:
  1867 
  1868     HOL.abs ~> HOL.abs_class.abs
  1869     HOL.divide ~> HOL.divide_class.divide
  1870     0 ~> HOL.zero_class.zero
  1871     1 ~> HOL.one_class.one
  1872     op + ~> HOL.plus_class.plus
  1873     op - ~> HOL.minus_class.minus
  1874     uminus ~> HOL.minus_class.uminus
  1875     op * ~> HOL.times_class.times
  1876     op < ~> HOL.ord_class.less
  1877     op <= > HOL.ord_class.less_eq
  1878     Nat.power ~> Power.power_class.power
  1879     Nat.size ~> Nat.size_class.size
  1880     Numeral.number_of ~> Numeral.number_class.number_of
  1881     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1882     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1883     Orderings.min ~> Orderings.ord_class.min
  1884     Orderings.max ~> Orderings.ord_class.max
  1885     Divides.op div ~> Divides.div_class.div
  1886     Divides.op mod ~> Divides.div_class.mod
  1887     Divides.op dvd ~> Divides.div_class.dvd
  1888 
  1889 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1890 
  1891 a) User-defined constants using any of the names "plus", "minus",
  1892 "times", "less" or "less_eq". The standard syntax translations for
  1893 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1894 names.
  1895 
  1896 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1897 INCOMPATIBILITY: use more specific names.
  1898 
  1899 c) Permutative equations (e.g. "a + b = b + a")
  1900 Since the change of names also changes the order of terms, permutative
  1901 rewrite rules may get applied in a different order. Experience shows
  1902 that this is rarely the case (only two adaptions in the whole Isabelle
  1903 distribution).  INCOMPATIBILITY: rewrite proofs
  1904 
  1905 d) ML code directly refering to constant names
  1906 This in general only affects hand-written proof tactics, simprocs and
  1907 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1908 Consider using @{const_name} antiquotation.
  1909 
  1910 * New class "default" with associated constant "default".
  1911 
  1912 * Function "sgn" is now overloaded and available on int, real, complex
  1913 (and other numeric types), using class "sgn".  Two possible defs of
  1914 sgn are given as equational assumptions in the classes sgn_if and
  1915 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1916 INCOMPATIBILITY.
  1917 
  1918 * Locale "partial_order" now unified with class "order" (cf. theory
  1919 Orderings), added parameter "less".  INCOMPATIBILITY.
  1920 
  1921 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1922 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1923 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1924 
  1925 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1926 changed order of proof goals in instance proofs.
  1927 
  1928 * The transitivity reasoner for partial and linear orders is set up
  1929 for classes "order" and "linorder".  Instances of the reasoner are available
  1930 in all contexts importing or interpreting the corresponding locales.
  1931 Method "order" invokes the reasoner separately; the reasoner
  1932 is also integrated with the Simplifier as a solver.  Diagnostic
  1933 command 'print_orders' shows the available instances of the reasoner
  1934 in the current context.
  1935 
  1936 * Localized monotonicity predicate in theory "Orderings"; integrated
  1937 lemmas max_of_mono and min_of_mono with this predicate.
  1938 INCOMPATIBILITY.
  1939 
  1940 * Formulation of theorem "dense" changed slightly due to integration
  1941 with new class dense_linear_order.
  1942 
  1943 * Uniform lattice theory development in HOL.
  1944 
  1945     constants "meet" and "join" now named "inf" and "sup"
  1946     constant "Meet" now named "Inf"
  1947 
  1948     classes "meet_semilorder" and "join_semilorder" now named
  1949       "lower_semilattice" and "upper_semilattice"
  1950     class "lorder" now named "lattice"
  1951     class "comp_lat" now named "complete_lattice"
  1952 
  1953     Instantiation of lattice classes allows explicit definitions
  1954     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1955 
  1956   INCOMPATIBILITY.  Theorem renames:
  1957 
  1958     meet_left_le            ~> inf_le1
  1959     meet_right_le           ~> inf_le2
  1960     join_left_le            ~> sup_ge1
  1961     join_right_le           ~> sup_ge2
  1962     meet_join_le            ~> inf_sup_ord
  1963     le_meetI                ~> le_infI
  1964     join_leI                ~> le_supI
  1965     le_meet                 ~> le_inf_iff
  1966     le_join                 ~> ge_sup_conv
  1967     meet_idempotent         ~> inf_idem
  1968     join_idempotent         ~> sup_idem
  1969     meet_comm               ~> inf_commute
  1970     join_comm               ~> sup_commute
  1971     meet_leI1               ~> le_infI1
  1972     meet_leI2               ~> le_infI2
  1973     le_joinI1               ~> le_supI1
  1974     le_joinI2               ~> le_supI2
  1975     meet_assoc              ~> inf_assoc
  1976     join_assoc              ~> sup_assoc
  1977     meet_left_comm          ~> inf_left_commute
  1978     meet_left_idempotent    ~> inf_left_idem
  1979     join_left_comm          ~> sup_left_commute
  1980     join_left_idempotent    ~> sup_left_idem
  1981     meet_aci                ~> inf_aci
  1982     join_aci                ~> sup_aci
  1983     le_def_meet             ~> le_iff_inf
  1984     le_def_join             ~> le_iff_sup
  1985     join_absorp2            ~> sup_absorb2
  1986     join_absorp1            ~> sup_absorb1
  1987     meet_absorp1            ~> inf_absorb1
  1988     meet_absorp2            ~> inf_absorb2
  1989     meet_join_absorp        ~> inf_sup_absorb
  1990     join_meet_absorp        ~> sup_inf_absorb
  1991     distrib_join_le         ~> distrib_sup_le
  1992     distrib_meet_le         ~> distrib_inf_le
  1993 
  1994     add_meet_distrib_left   ~> add_inf_distrib_left
  1995     add_join_distrib_left   ~> add_sup_distrib_left
  1996     is_join_neg_meet        ~> is_join_neg_inf
  1997     is_meet_neg_join        ~> is_meet_neg_sup
  1998     add_meet_distrib_right  ~> add_inf_distrib_right
  1999     add_join_distrib_right  ~> add_sup_distrib_right
  2000     add_meet_join_distribs  ~> add_sup_inf_distribs
  2001     join_eq_neg_meet        ~> sup_eq_neg_inf
  2002     meet_eq_neg_join        ~> inf_eq_neg_sup
  2003     add_eq_meet_join        ~> add_eq_inf_sup
  2004     meet_0_imp_0            ~> inf_0_imp_0
  2005     join_0_imp_0            ~> sup_0_imp_0
  2006     meet_0_eq_0             ~> inf_0_eq_0
  2007     join_0_eq_0             ~> sup_0_eq_0
  2008     neg_meet_eq_join        ~> neg_inf_eq_sup
  2009     neg_join_eq_meet        ~> neg_sup_eq_inf
  2010     join_eq_if              ~> sup_eq_if
  2011 
  2012     mono_meet               ~> mono_inf
  2013     mono_join               ~> mono_sup
  2014     meet_bool_eq            ~> inf_bool_eq
  2015     join_bool_eq            ~> sup_bool_eq
  2016     meet_fun_eq             ~> inf_fun_eq
  2017     join_fun_eq             ~> sup_fun_eq
  2018     meet_set_eq             ~> inf_set_eq
  2019     join_set_eq             ~> sup_set_eq
  2020     meet1_iff               ~> inf1_iff
  2021     meet2_iff               ~> inf2_iff
  2022     meet1I                  ~> inf1I
  2023     meet2I                  ~> inf2I
  2024     meet1D1                 ~> inf1D1
  2025     meet2D1                 ~> inf2D1
  2026     meet1D2                 ~> inf1D2
  2027     meet2D2                 ~> inf2D2
  2028     meet1E                  ~> inf1E
  2029     meet2E                  ~> inf2E
  2030     join1_iff               ~> sup1_iff
  2031     join2_iff               ~> sup2_iff
  2032     join1I1                 ~> sup1I1
  2033     join2I1                 ~> sup2I1
  2034     join1I1                 ~> sup1I1
  2035     join2I2                 ~> sup1I2
  2036     join1CI                 ~> sup1CI
  2037     join2CI                 ~> sup2CI
  2038     join1E                  ~> sup1E
  2039     join2E                  ~> sup2E
  2040 
  2041     is_meet_Meet            ~> is_meet_Inf
  2042     Meet_bool_def           ~> Inf_bool_def
  2043     Meet_fun_def            ~> Inf_fun_def
  2044     Meet_greatest           ~> Inf_greatest
  2045     Meet_lower              ~> Inf_lower
  2046     Meet_set_def            ~> Inf_set_def
  2047 
  2048     Sup_def                 ~> Sup_Inf
  2049     Sup_bool_eq             ~> Sup_bool_def
  2050     Sup_fun_eq              ~> Sup_fun_def
  2051     Sup_set_eq              ~> Sup_set_def
  2052 
  2053     listsp_meetI            ~> listsp_infI
  2054     listsp_meet_eq          ~> listsp_inf_eq
  2055 
  2056     meet_min                ~> inf_min
  2057     join_max                ~> sup_max
  2058 
  2059 * Added syntactic class "size"; overloaded constant "size" now has
  2060 type "'a::size ==> bool"
  2061 
  2062 * Internal reorganisation of `size' of datatypes: size theorems
  2063 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2064 simplification rules by default!); theorems "prod.size" now named
  2065 "*.size".
  2066 
  2067 * Class "div" now inherits from class "times" rather than "type".
  2068 INCOMPATIBILITY.
  2069 
  2070 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2071 Linorder etc.  have disappeared; operations defined in terms of
  2072 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2073 
  2074 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2075 
  2076 * HOL-Word: New extensive library and type for generic, fixed size
  2077 machine words, with arithemtic, bit-wise, shifting and rotating
  2078 operations, reflection into int, nat, and bool lists, automation for
  2079 linear arithmetic (by automatic reflection into nat or int), including
  2080 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2081 arithmetic type classes, supporting automatic simplification of
  2082 numerals on all operations.
  2083 
  2084 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2085 
  2086 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2087 
  2088 * Code generator library theories:
  2089   - Code_Integer represents HOL integers by big integer literals in target
  2090     languages.
  2091   - Code_Char represents HOL characters by character literals in target
  2092     languages.
  2093   - Code_Char_chr like Code_Char, but also offers treatment of character
  2094     codes; includes Code_Integer.
  2095   - Executable_Set allows to generate code for finite sets using lists.
  2096   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2097     denominator).
  2098   - Executable_Real implements a subset of real numbers, namly those
  2099     representable by rational numbers.
  2100   - Efficient_Nat implements natural numbers by integers, which in general will
  2101     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2102     includes Code_Integer.
  2103   - Code_Index provides an additional datatype index which is mapped to
  2104     target-language built-in integers.
  2105   - Code_Message provides an additional datatype message_string which is isomorphic to
  2106     strings; messages are mapped to target-language strings.
  2107 
  2108 * New package for inductive predicates
  2109 
  2110   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2111 
  2112     inductive
  2113       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2114       for z_1 :: U_1 and ... and z_n :: U_m
  2115     where
  2116       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2117     | ...
  2118 
  2119   with full support for type-inference, rather than
  2120 
  2121     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2122 
  2123     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2124     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2125 
  2126     inductive "s z_1 ... z_m"
  2127     intros
  2128       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2129       ...
  2130 
  2131   For backward compatibility, there is a wrapper allowing inductive
  2132   sets to be defined with the new package via
  2133 
  2134     inductive_set
  2135       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2136       for z_1 :: U_1 and ... and z_n :: U_m
  2137     where
  2138       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2139     | ...
  2140 
  2141   or
  2142 
  2143     inductive_set
  2144       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2145       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2146       for z_1 :: U_1 and ... and z_n :: U_m
  2147     where
  2148       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2149     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2150     | ...
  2151 
  2152   if the additional syntax "p ..." is required.
  2153 
  2154   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2155   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2156 
  2157   INCOMPATIBILITIES:
  2158 
  2159   - Since declaration and definition of inductive sets or predicates
  2160     is no longer separated, abbreviations involving the newly
  2161     introduced sets or predicates must be specified together with the
  2162     introduction rules after the 'where' keyword (see above), rather
  2163     than before the actual inductive definition.
  2164 
  2165   - The variables in induction and elimination rules are now
  2166     quantified in the order of their occurrence in the introduction
  2167     rules, rather than in alphabetical order. Since this may break
  2168     some proofs, these proofs either have to be repaired, e.g. by
  2169     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2170     statements of the form
  2171 
  2172       case (rule_i a_i_1 ... a_i_{k_i})
  2173 
  2174     or the old order of quantification has to be restored by explicitly adding
  2175     meta-level quantifiers in the introduction rules, i.e.
  2176 
  2177       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2178 
  2179   - The format of the elimination rules is now
  2180 
  2181       p z_1 ... z_m x_1 ... x_n ==>
  2182         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2183         ==> ... ==> P
  2184 
  2185     for predicates and
  2186 
  2187       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2188         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2189         ==> ... ==> P
  2190 
  2191     for sets rather than
  2192 
  2193       x : s z_1 ... z_m ==>
  2194         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2195         ==> ... ==> P
  2196 
  2197     This may require terms in goals to be expanded to n-tuples
  2198     (e.g. using case_tac or simplification with the split_paired_all
  2199     rule) before the above elimination rule is applicable.
  2200 
  2201   - The elimination or case analysis rules for (mutually) inductive
  2202     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2203     list of rules "p_1_..._p_k.elims" is no longer available.
  2204 
  2205 * New package "function"/"fun" for general recursive functions,
  2206 supporting mutual and nested recursion, definitions in local contexts,
  2207 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2208 for small examples, and the separate tutorial on the function
  2209 package. The old recdef "package" is still available as before, but
  2210 users are encouraged to use the new package.
  2211 
  2212 * Method "lexicographic_order" automatically synthesizes termination
  2213 relations as lexicographic combinations of size measures. 
  2214 
  2215 * Case-expressions allow arbitrary constructor-patterns (including
  2216 "_") and take their order into account, like in functional
  2217 programming.  Internally, this is translated into nested
  2218 case-expressions; missing cases are added and mapped to the predefined
  2219 constant "undefined". In complicated cases printing may no longer show
  2220 the original input but the internal form. Lambda-abstractions allow
  2221 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2222 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2223 variable.
  2224 
  2225 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2226 is an abbreviation for "of_nat :: nat => int". The simplification
  2227 rules for "of_nat" have been changed to work like "int" did
  2228 previously.  Potential INCOMPATIBILITY:
  2229   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2230   - of_nat_diff and of_nat_mult are no longer default simp rules
  2231 
  2232 * Method "algebra" solves polynomial equations over (semi)rings using
  2233 Groebner bases. The (semi)ring structure is defined by locales and the
  2234 tool setup depends on that generic context. Installing the method for
  2235 a specific type involves instantiating the locale and possibly adding
  2236 declarations for computation on the coefficients.  The method is
  2237 already instantiated for natural numbers and for the axiomatic class
  2238 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2239 CALCULEMUS 2007 for the general principles underlying this
  2240 architecture of context-aware proof-tools.
  2241 
  2242 * Method "ferrack" implements quantifier elimination over
  2243 special-purpose dense linear orders using locales (analogous to
  2244 "algebra"). The method is already installed for class
  2245 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2246 rat, etc.
  2247 
  2248 * Former constant "List.op @" now named "List.append".  Use ML
  2249 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2250 circumvent possible incompatibilities when working on ML level.
  2251 
  2252 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2253 
  2254 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2255 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2256 
  2257 * New syntax for Haskell-like list comprehension (input only), eg.
  2258 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2259 
  2260 * The special syntax for function "filter" has changed from [x :
  2261 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2262 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2263 
  2264 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2265 defined on nat only, as an abbreviation for [a..<Suc b]
  2266 INCOMPATIBILITY.
  2267 
  2268 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2269 
  2270 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2271 
  2272 * New lemma collection field_simps (an extension of ring_simps) for
  2273 manipulating (in)equations involving division. Multiplies with all
  2274 denominators that can be proved to be non-zero (in equations) or
  2275 positive/negative (in inequations).
  2276 
  2277 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2278 have been improved and renamed to ring_simps, group_simps and
  2279 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2280 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2281 
  2282 * Theory Library/Commutative_Ring: switched from recdef to function
  2283 package; constants add, mul, pow now curried.  Infix syntax for
  2284 algebraic operations.
  2285 
  2286 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2287 INCOMPATIBILITY.
  2288 
  2289 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2290 INCOMPATIBILITY.
  2291 
  2292 * HOL/records: generalised field-update to take a function on the
  2293 field rather than the new value: r(|A := x|) is translated to A_update
  2294 (K x) r The K-combinator that is internally used is called K_record.
  2295 INCOMPATIBILITY: Usage of the plain update functions has to be
  2296 adapted.
  2297  
  2298 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2299 * x = 0, which are required for a semiring.  Richer structures do not
  2300 inherit from semiring_0 anymore, because this property is a theorem
  2301 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2302 there is more to prove, but this is mostly trivial.
  2303 
  2304 * Class "recpower" is generalized to arbitrary monoids, not just
  2305 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2306 commutativity or semiring properties additionally.
  2307 
  2308 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2309 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2310 better use 'abbreviation'.
  2311 
  2312 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2313 
  2314 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2315 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2316 significant changes for setting up numeral syntax for types:
  2317   - New constants Numeral.pred and Numeral.succ instead
  2318       of former Numeral.bin_pred and Numeral.bin_succ.
  2319   - Use integer operations instead of bin_add, bin_mult and so on.
  2320   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2321   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2322 
  2323 See src/HOL/Integ/IntArith.thy for an example setup.
  2324 
  2325 * Command 'normal_form' computes the normal form of a term that may
  2326 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2327 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2328 heavy-duty computations because the functions are compiled to ML
  2329 first.  Correspondingly, a method "normalization" is provided.  See
  2330 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2331 
  2332 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2333 25 like -->); output depends on the "iff" print_mode, the default is
  2334 "A = B" (with priority 50).
  2335 
  2336 * Relations less (<) and less_eq (<=) are also available on type bool.
  2337 Modified syntax to disallow nesting without explicit parentheses,
  2338 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2339 INCOMPATIBILITY.
  2340 
  2341 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2342 
  2343 * Relation composition operator "op O" now has precedence 75 and binds
  2344 stronger than union and intersection. INCOMPATIBILITY.
  2345 
  2346 * The old set interval syntax "{m..n(}" (and relatives) has been
  2347 removed.  Use "{m..<n}" (and relatives) instead.
  2348 
  2349 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2350 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2351 ``declare [[simproc del: neq]]''.
  2352 
  2353 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2354 True/False.
  2355 
  2356 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2357 
  2358 * Theorem setsum_mult renamed to setsum_right_distrib.
  2359 
  2360 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2361 ``rule'' method.
  2362 
  2363 * Reimplemented methods "sat" and "satx", with several improvements:
  2364 goals no longer need to be stated as "<prems> ==> False", equivalences
  2365 (i.e. "=" on type bool) are handled, variable names of the form
  2366 "lit_<n>" are no longer reserved, significant speedup.
  2367 
  2368 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2369 zChaff is still supported as well.
  2370 
  2371 * 'inductive' and 'datatype': provide projections of mutual rules,
  2372 bundled as foo_bar.inducts;
  2373 
  2374 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2375 Library.
  2376 
  2377 * Library: moved theory Accessible_Part to main HOL.
  2378 
  2379 * Library: added theory Coinductive_List of potentially infinite lists
  2380 as greatest fixed-point.
  2381 
  2382 * Library: added theory AssocList which implements (finite) maps as
  2383 association lists.
  2384 
  2385 * Method "evaluation" solves goals (i.e. a boolean expression)
  2386 efficiently by compiling it to ML.  The goal is "proved" (via an
  2387 oracle) if it evaluates to True.
  2388 
  2389 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2390 also when invoked by the simplifier.  This results in the Simplifier
  2391 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2392 Configuration option fast_arith_split_limit=0 recovers the old
  2393 behavior.
  2394 
  2395 * Support for hex (0x20) and binary (0b1001) numerals.
  2396 
  2397 * New method: reify eqs (t), where eqs are equations for an
  2398 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2399 parameter, computes a term s::'b and a list xs::'a list and proves the
  2400 theorem I xs s = t. This is also known as reification or quoting. The
  2401 resulting theorem is applied to the subgoal to substitute t with I xs
  2402 s.  If t is omitted, the subgoal itself is reified.
  2403 
  2404 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2405 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2406 where f is supposed to be a computable function (in the sense of code
  2407 generattion). The method uses reify to compute s and xs as above then
  2408 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2409 r and finally gets the theorem t = r, which is again applied to the
  2410 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2411 
  2412 * Reflection: Automatic reification now handels binding, an example is
  2413 available in src/HOL/ex/ReflectionEx.thy
  2414 
  2415 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2416 command 'statespace' that is similar to 'record', but introduces an
  2417 abstract specification based on the locale infrastructure instead of
  2418 HOL types.  This leads to extra flexibility in composing state spaces,
  2419 in particular multiple inheritance and renaming of components.
  2420 
  2421 
  2422 *** HOL-Complex ***
  2423 
  2424 * Hyperreal: Functions root and sqrt are now defined on negative real
  2425 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2426 Nonnegativity side conditions have been removed from many lemmas, so
  2427 that more subgoals may now be solved by simplification; potential
  2428 INCOMPATIBILITY.
  2429 
  2430 * Real: new type classes formalize real normed vector spaces and
  2431 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2432 and norm :: 'a => real.
  2433 
  2434 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2435 reals into other types. The overloaded constant Reals :: 'a set is now
  2436 defined as range of_real; potential INCOMPATIBILITY.
  2437 
  2438 * Real: proper support for ML code generation, including 'quickcheck'.
  2439 Reals are implemented as arbitrary precision rationals.
  2440 
  2441 * Hyperreal: Several constants that previously worked only for the
  2442 reals have been generalized, so they now work over arbitrary vector
  2443 spaces. Type annotations may need to be added in some cases; potential
  2444 INCOMPATIBILITY.
  2445 
  2446   Infinitesimal  :: ('a::real_normed_vector) star set
  2447   HFinite        :: ('a::real_normed_vector) star set
  2448   HInfinite      :: ('a::real_normed_vector) star set
  2449   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2450   monad          :: ('a::real_normed_vector) star => 'a star set
  2451   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2452   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2453   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2454   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2455   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2456   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2457   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2458   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2459   sgn            :: 'a::real_normed_vector => 'a
  2460   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2461 
  2462 * Complex: Some complex-specific constants are now abbreviations for
  2463 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2464 hnorm.  Other constants have been entirely removed in favor of the
  2465 polymorphic versions (INCOMPATIBILITY):
  2466 
  2467   approx        <-- capprox
  2468   HFinite       <-- CFinite
  2469   HInfinite     <-- CInfinite
  2470   Infinitesimal <-- CInfinitesimal
  2471   monad         <-- cmonad
  2472   galaxy        <-- cgalaxy
  2473   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2474   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2475   (ns)deriv     <-- (ns)cderiv
  2476 
  2477 
  2478 *** HOL-Algebra ***
  2479 
  2480 * Formalisation of ideals and the quotient construction over rings.
  2481 
  2482 * Order and lattice theory no longer based on records.
  2483 INCOMPATIBILITY.
  2484 
  2485 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2486 greatest_closed.  INCOMPATIBILITY.
  2487 
  2488 * Method algebra is now set up via an attribute.  For examples see
  2489 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2490 of algebraic structures.
  2491 
  2492 * Renamed theory CRing to Ring.
  2493 
  2494 
  2495 *** HOL-Nominal ***
  2496 
  2497 * Substantial, yet incomplete support for nominal datatypes (binding
  2498 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2499 src/HOL/Nominal/Examples.  Prospective users should consult
  2500 http://isabelle.in.tum.de/nominal/
  2501 
  2502 
  2503 *** ML ***
  2504 
  2505 * ML basics: just one true type int, which coincides with IntInf.int
  2506 (even on SML/NJ).
  2507 
  2508 * ML within Isar: antiquotations allow to embed statically-checked
  2509 formal entities in the source, referring to the context available at
  2510 compile-time.  For example:
  2511 
  2512 ML {* @{sort "{zero,one}"} *}
  2513 ML {* @{typ "'a => 'b"} *}
  2514 ML {* @{term "%x. x"} *}
  2515 ML {* @{prop "x == y"} *}
  2516 ML {* @{ctyp "'a => 'b"} *}
  2517 ML {* @{cterm "%x. x"} *}
  2518 ML {* @{cprop "x == y"} *}
  2519 ML {* @{thm asm_rl} *}
  2520 ML {* @{thms asm_rl} *}
  2521 ML {* @{type_name c} *}
  2522 ML {* @{type_syntax c} *}
  2523 ML {* @{const_name c} *}
  2524 ML {* @{const_syntax c} *}
  2525 ML {* @{context} *}
  2526 ML {* @{theory} *}
  2527 ML {* @{theory Pure} *}
  2528 ML {* @{theory_ref} *}
  2529 ML {* @{theory_ref Pure} *}
  2530 ML {* @{simpset} *}
  2531 ML {* @{claset} *}
  2532 ML {* @{clasimpset} *}
  2533 
  2534 The same works for sources being ``used'' within an Isar context.
  2535 
  2536 * ML in Isar: improved error reporting; extra verbosity with
  2537 ML_Context.trace enabled.
  2538 
  2539 * Pure/General/table.ML: the join operations now works via exceptions
  2540 DUP/SAME instead of type option. This is simpler in simple cases, and
  2541 admits slightly more efficient complex applications.
  2542 
  2543 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2544 use Context.generic instead of just theory.
  2545 
  2546 * Pure: datatype Context.generic joins theory/Proof.context and
  2547 provides some facilities for code that works in either kind of
  2548 context, notably GenericDataFun for uniform theory and proof data.
  2549 
  2550 * Pure: simplified internal attribute type, which is now always
  2551 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2552 local (Proof.context) attributes have been discontinued, while
  2553 minimizing code duplication. Thm.rule_attribute and
  2554 Thm.declaration_attribute build canonical attributes; see also structure
  2555 Context for further operations on Context.generic, notably
  2556 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2557 declarations and definitions.
  2558 
  2559 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2560 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2561 init only required for impure data. INCOMPATIBILITY: empty really need
  2562 to be empty (no dependencies on theory content!)
  2563 
  2564 * Pure/kernel: consts certification ignores sort constraints given in
  2565 signature declarations. (This information is not relevant to the
  2566 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2567 potential INCOMPATIBILITY.
  2568 
  2569 * Pure: axiomatic type classes are now purely definitional, with
  2570 explicit proofs of class axioms and super class relations performed
  2571 internally. See Pure/axclass.ML for the main internal interfaces --
  2572 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2573 AxClass.axiomatize_class/classrel/arity supersede
  2574 Sign.add_classes/classrel/arities.
  2575 
  2576 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2577 global/local versions on theory vs. Proof.context have been
  2578 discontinued; Attrib.syntax and Method.syntax have been adapted
  2579 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2580 attributes, methods, etc.
  2581 
  2582 * Pure: several functions of signature "... -> theory -> theory * ..."
  2583 have been reoriented to "... -> theory -> ... * theory" in order to
  2584 allow natural usage in combination with the ||>, ||>>, |-> and
  2585 fold_map combinators.
  2586 
  2587 * Pure: official theorem names (closed derivations) and additional
  2588 comments (tags) are now strictly separate.  Name hints -- which are
  2589 maintained as tags -- may be attached any time without affecting the
  2590 derivation.
  2591 
  2592 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2593 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2594 achieve the old behaviour.
  2595 
  2596 * Pure: the "Goal" constant is now called "prop", supporting a
  2597 slightly more general idea of ``protecting'' meta-level rule
  2598 statements.
  2599 
  2600 * Pure: Logic.(un)varify only works in a global context, which is now
  2601 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2602 Logic.legacy_(un)varify as temporary workaround.
  2603 
  2604 * Pure: structure Name provides scalable operations for generating
  2605 internal variable names, notably Name.variants etc.  This replaces
  2606 some popular functions from term.ML:
  2607 
  2608   Term.variant		->  Name.variant
  2609   Term.variantlist	->  Name.variant_list
  2610   Term.invent_names	->  Name.invent_list
  2611 
  2612 Note that low-level renaming rarely occurs in new code -- operations
  2613 from structure Variable are used instead (see below).
  2614 
  2615 * Pure: structure Variable provides fundamental operations for proper
  2616 treatment of fixed/schematic variables in a context.  For example,
  2617 Variable.import introduces fixes for schematics of given facts and
  2618 Variable.export reverses the effect (up to renaming) -- this replaces
  2619 various freeze_thaw operations.
  2620 
  2621 * Pure: structure Goal provides simple interfaces for
  2622 init/conclude/finish and tactical prove operations (replacing former
  2623 Tactic.prove).  Goal.prove is the canonical way to prove results
  2624 within a given context; Goal.prove_global is a degraded version for
  2625 theory level goals, including a global Drule.standard.  Note that
  2626 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2627 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2628 in a locale context).
  2629 
  2630 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2631 and type checking (Syntax.check_term etc.), with common combinations
  2632 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2633 which are considered legacy and await removal.
  2634 
  2635 * Pure/Syntax: generic interfaces for type unchecking
  2636 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2637 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2638 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2639 available for convenience, but refer to the very same operations using
  2640 a mere theory instead of a full context.
  2641 
  2642 * Isar: simplified treatment of user-level errors, using exception
  2643 ERROR of string uniformly.  Function error now merely raises ERROR,
  2644 without any side effect on output channels.  The Isar toplevel takes
  2645 care of proper display of ERROR exceptions.  ML code may use plain
  2646 handle/can/try; cat_error may be used to concatenate errors like this:
  2647 
  2648   ... handle ERROR msg => cat_error msg "..."
  2649 
  2650 Toplevel ML code (run directly or through the Isar toplevel) may be
  2651 embedded into the Isar toplevel with exception display/debug like
  2652 this:
  2653 
  2654   Isar.toplevel (fn () => ...)
  2655 
  2656 INCOMPATIBILITY, removed special transform_error facilities, removed
  2657 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2658 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2659 -- use plain ERROR instead.
  2660 
  2661 * Isar: theory setup now has type (theory -> theory), instead of a
  2662 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2663 
  2664 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2665 ProofContext.debug/verbose flags.
  2666 
  2667 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2668 theory before entering a proof state.  Transactions now always see a
  2669 quasi-functional intermediate checkpoint, both in interactive and
  2670 batch mode.
  2671 
  2672 * Isar: simplified interfaces for outer syntax.  Renamed
  2673 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2674 OuterSyntax.add_parsers -- this functionality is now included in
  2675 OuterSyntax.command etc.  INCOMPATIBILITY.
  2676 
  2677 * Simplifier: the simpset of a running simplification process now
  2678 contains a proof context (cf. Simplifier.the_context), which is the
  2679 very context that the initial simpset has been retrieved from (by
  2680 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2681 (solver, looper etc.) may depend on arbitrary proof data.
  2682 
  2683 * Simplifier.inherit_context inherits the proof context (plus the
  2684 local bounds) of the current simplification process; any simproc
  2685 etc. that calls the Simplifier recursively should do this!  Removed
  2686 former Simplifier.inherit_bounds, which is already included here --
  2687 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2688 specify an explicit context using Simplifier.context/theory_context.
  2689 
  2690 * Simplifier/Classical Reasoner: more abstract interfaces
  2691 change_simpset/claset for modifying the simpset/claset reference of a
  2692 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2693 INCOMPATIBILITY.
  2694 
  2695 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2696 "Trueprop" etc.
  2697 
  2698 
  2699 *** System ***
  2700 
  2701 * settings: the default heap location within ISABELLE_HOME_USER now
  2702 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2703 Isabelle installations.
  2704 
  2705 * isabelle-process: option -S (secure mode) disables some critical
  2706 operations, notably runtime compilation and evaluation of ML source
  2707 code.
  2708 
  2709 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2710 
  2711 * Support for parallel execution, using native multicore support of
  2712 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2713 independent theories, according to the given theory header
  2714 specifications. The maximum number of worker threads is specified via
  2715 usedir option -M or the "max-threads" setting in Proof General. A
  2716 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2717 to 6 on a 8-core machine.  User-code needs to observe certain
  2718 guidelines for thread-safe programming, see appendix A in the Isar
  2719 Implementation manual.
  2720 
  2721 
  2722 
  2723 New in Isabelle2005 (October 2005)
  2724 ----------------------------------
  2725 
  2726 *** General ***
  2727 
  2728 * Theory headers: the new header syntax for Isar theories is
  2729 
  2730   theory <name>
  2731   imports <theory1> ... <theoryN>
  2732   uses <file1> ... <fileM>
  2733   begin
  2734 
  2735 where the 'uses' part is optional.  The previous syntax
  2736 
  2737   theory <name> = <theory1> + ... + <theoryN>:
  2738 
  2739 will disappear in the next release.  Use isatool fixheaders to convert
  2740 existing theory files.  Note that there is no change in ancient
  2741 non-Isar theories now, but these will disappear soon.
  2742 
  2743 * Theory loader: parent theories can now also be referred to via
  2744 relative and absolute paths.
  2745 
  2746 * Command 'find_theorems' searches for a list of criteria instead of a
  2747 list of constants. Known criteria are: intro, elim, dest, name:string,
  2748 simp:term, and any term. Criteria can be preceded by '-' to select
  2749 theorems that do not match. Intro, elim, dest select theorems that
  2750 match the current goal, name:s selects theorems whose fully qualified
  2751 name contain s, and simp:term selects all simplification rules whose
  2752 lhs match term.  Any other term is interpreted as pattern and selects
  2753 all theorems matching the pattern. Available in ProofGeneral under
  2754 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2755 
  2756   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2757 
  2758 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2759 matching the current goal as introduction rule and not having "HOL."
  2760 in their name (i.e. not being defined in theory HOL).
  2761 
  2762 * Command 'thms_containing' has been discontinued in favour of
  2763 'find_theorems'; INCOMPATIBILITY.
  2764 
  2765 * Communication with Proof General is now 8bit clean, which means that
  2766 Unicode text in UTF-8 encoding may be used within theory texts (both
  2767 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2768 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2769 
  2770   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2771   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2772 
  2773 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2774 Classical Reasoner.  Typical big applications run around 2 times
  2775 faster.
  2776 
  2777 
  2778 *** Document preparation ***
  2779 
  2780 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2781 of raw sources.  Only those symbols that do not require additional
  2782 LaTeX packages (depending on comments in isabellesym.sty) are
  2783 displayed properly, everything else is left verbatim.  isatool display
  2784 and isatool print are used as front ends (these are subject to the
  2785 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2786 
  2787 * Command tags control specific markup of certain regions of text,
  2788 notably folding and hiding.  Predefined tags include "theory" (for
  2789 theory begin and end), "proof" for proof commands, and "ML" for
  2790 commands involving ML code; the additional tags "visible" and
  2791 "invisible" are unused by default.  Users may give explicit tag
  2792 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2793 interpretation of tags is determined by the LaTeX job during document
  2794 preparation: see option -V of isatool usedir, or options -n and -t of
  2795 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2796 \isadroptag.
  2797 
  2798 Several document versions may be produced at the same time via isatool
  2799 usedir (the generated index.html will link all of them).  Typical
  2800 specifications include ''-V document=theory,proof,ML'' to present
  2801 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2802 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2803 these parts without any formal replacement text.  The Isabelle site
  2804 default settings produce ''document'' and ''outline'' versions as
  2805 specified above.
  2806 
  2807 * Several new antiquotations:
  2808 
  2809   @{term_type term} prints a term with its type annotated;
  2810 
  2811   @{typeof term} prints the type of a term;
  2812 
  2813   @{const const} is the same as @{term const}, but checks that the
  2814   argument is a known logical constant;
  2815 
  2816   @{term_style style term} and @{thm_style style thm} print a term or
  2817   theorem applying a "style" to it
  2818 
  2819   @{ML text}
  2820 
  2821 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2822 definitions, equations, inequations etc., 'concl' printing only the
  2823 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2824 to print the specified premise.  TermStyle.add_style provides an ML
  2825 interface for introducing further styles.  See also the "LaTeX Sugar"
  2826 document practical applications.  The ML antiquotation prints
  2827 type-checked ML expressions verbatim.
  2828 
  2829 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2830 and 'text' support optional locale specification '(in loc)', which
  2831 specifies the default context for interpreting antiquotations.  For
  2832 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2833 
  2834 * Option 'locale=NAME' of antiquotations specifies an alternative
  2835 context interpreting the subsequent argument.  For example: @{thm
  2836 [locale=lattice] inf_assoc}.
  2837 
  2838 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2839 a proof context.
  2840 
  2841 * Proper output of antiquotations for theory commands involving a
  2842 proof context (such as 'locale' or 'theorem (in loc) ...').
  2843 
  2844 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2845 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2846 
  2847 * isatool usedir: new option -C (default true) controls whether option
  2848 -D should include a copy of the original document directory; -C false
  2849 prevents unwanted effects such as copying of administrative CVS data.
  2850 
  2851 
  2852 *** Pure ***
  2853 
  2854 * Considerably improved version of 'constdefs' command.  Now performs
  2855 automatic type-inference of declared constants; additional support for
  2856 local structure declarations (cf. locales and HOL records), see also
  2857 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2858 sequential dependencies of definitions within a single 'constdefs'
  2859 section; moreover, the declared name needs to be an identifier.  If
  2860 all fails, consider to fall back on 'consts' and 'defs' separately.
  2861 
  2862 * Improved indexed syntax and implicit structures.  First of all,
  2863 indexed syntax provides a notational device for subscripted
  2864 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2865 expressions.  Secondly, in a local context with structure
  2866 declarations, number indexes \<^sub>n or the empty index (default
  2867 number 1) refer to a certain fixed variable implicitly; option
  2868 show_structs controls printing of implicit structures.  Typical
  2869 applications of these concepts involve record types and locales.
  2870 
  2871 * New command 'no_syntax' removes grammar declarations (and
  2872 translations) resulting from the given syntax specification, which is
  2873 interpreted in the same manner as for the 'syntax' command.
  2874 
  2875 * 'Advanced' translation functions (parse_translation etc.) may depend
  2876 on the signature of the theory context being presently used for
  2877 parsing/printing, see also isar-ref manual.
  2878 
  2879 * Improved 'oracle' command provides a type-safe interface to turn an
  2880 ML expression of type theory -> T -> term into a primitive rule of
  2881 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2882 is already included here); see also FOL/ex/IffExample.thy;
  2883 INCOMPATIBILITY.
  2884 
  2885 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2886 before); "cI" is no longer bound, use "c.intro" instead.
  2887 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2888 axclasses vs. locales.
  2889 
  2890 * Improved internal renaming of symbolic identifiers -- attach primes
  2891 instead of base 26 numbers.
  2892 
  2893 * New flag show_question_marks controls printing of leading question
  2894 marks in schematic variable names.
  2895 
  2896 * In schematic variable names, *any* symbol following \<^isub> or
  2897 \<^isup> is now treated as part of the base name.  For example, the
  2898 following works without printing of awkward ".0" indexes:
  2899 
  2900   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2901     by simp
  2902 
  2903 * Inner syntax includes (*(*nested*) comments*).
  2904 
  2905 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2906 annotations as "(00...)".
  2907 
  2908 * Clear separation of logical types and nonterminals, where the latter
  2909 may only occur in 'syntax' specifications or type abbreviations.
  2910 Before that distinction was only partially implemented via type class
  2911 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2912 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2913 exotic syntax specifications may require further adaption
  2914 (e.g. Cube/Cube.thy).
  2915 
  2916 * Removed obsolete type class "logic", use the top sort {} instead.
  2917 Note that non-logical types should be declared as 'nonterminals'
  2918 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2919 specifications.
  2920 
  2921 * Attributes 'induct' and 'cases': type or set names may now be
  2922 locally fixed variables as well.
  2923 
  2924 * Simplifier: can now control the depth to which conditional rewriting
  2925 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2926 Limit.
  2927 
  2928 * Simplifier: simplification procedures may now take the current
  2929 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2930 interface), which is very useful for calling the Simplifier
  2931 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2932 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2933 low-level mk_simproc no longer applies Logic.varify internally, to
  2934 allow for use in a context of fixed variables.
  2935 
  2936 * thin_tac now works even if the assumption being deleted contains !!
  2937 or ==>.  More generally, erule now works even if the major premise of
  2938 the elimination rule contains !! or ==>.
  2939 
  2940 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2941 
  2942 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2943 from Pure, which contains all common declarations already.  Both
  2944 theories are defined via plain Isabelle/Isar .thy files.
  2945 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2946 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2947 use isatool fixcpure to adapt your theory and ML sources.
  2948 
  2949 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2950 selections of theorems in named facts via index ranges.
  2951 
  2952 * 'print_theorems': in theory mode, really print the difference
  2953 wrt. the last state (works for interactive theory development only),
  2954 in proof mode print all local facts (cf. 'print_facts');
  2955 
  2956 * 'hide': option '(open)' hides only base names.
  2957 
  2958 * More efficient treatment of intermediate checkpoints in interactive
  2959 theory development.
  2960 
  2961 * Code generator is now invoked via code_module (incremental code
  2962 generation) and code_library (modular code generation, ML structures
  2963 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2964 must be quoted when used as identifiers.
  2965 
  2966 * New 'value' command for reading, evaluating and printing terms using
  2967 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2968 quoted when used as identifier.
  2969 
  2970 
  2971 *** Locales ***
  2972 
  2973 * New commands for the interpretation of locale expressions in
  2974 theories (1), locales (2) and proof contexts (3).  These generate
  2975 proof obligations from the expression specification.  After the
  2976 obligations have been discharged, theorems of the expression are added
  2977 to the theory, target locale or proof context.  The synopsis of the
  2978 commands is a follows:
  2979 
  2980   (1) interpretation expr inst
  2981   (2) interpretation target < expr
  2982   (3) interpret expr inst
  2983 
  2984 Interpretation in theories and proof contexts require a parameter
  2985 instantiation of terms from the current context.  This is applied to
  2986 specifications and theorems of the interpreted expression.
  2987 Interpretation in locales only permits parameter renaming through the
  2988 locale expression.  Interpretation is smart in that interpretations
  2989 that are active already do not occur in proof obligations, neither are
  2990 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2991 inspect active interpretations of a particular locale.  For details,
  2992 see the Isar Reference manual.  Examples can be found in
  2993 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2994 
  2995 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2996 'interpret' instead.
  2997 
  2998 * New context element 'constrains' for adding type constraints to
  2999 parameters.
  3000 
  3001 * Context expressions: renaming of parameters with syntax
  3002 redeclaration.
  3003 
  3004 * Locale declaration: 'includes' disallowed.
  3005 
  3006 * Proper static binding of attribute syntax -- i.e. types / terms /
  3007 facts mentioned as arguments are always those of the locale definition
  3008 context, independently of the context of later invocations.  Moreover,
  3009 locale operations (renaming and type / term instantiation) are applied
  3010 to attribute arguments as expected.
  3011 
  3012 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  3013 actual attributes; rare situations may require Attrib.attribute to
  3014 embed those attributes into Attrib.src that lack concrete syntax.
  3015 Attribute implementations need to cooperate properly with the static
  3016 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  3017 Attrib.XXX_thm etc. already do the right thing without further
  3018 intervention.  Only unusual applications -- such as "where" or "of"
  3019 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  3020 on the context and the facts involved -- may have to assign parsed
  3021 values to argument tokens explicitly.
  3022 
  3023 * Changed parameter management in theorem generation for long goal
  3024 statements with 'includes'.  INCOMPATIBILITY: produces a different
  3025 theorem statement in rare situations.
  3026 
  3027 * Locale inspection command 'print_locale' omits notes elements.  Use
  3028 'print_locale!' to have them included in the output.
  3029 
  3030 
  3031 *** Provers ***
  3032 
  3033 * Provers/hypsubst.ML: improved version of the subst method, for
  3034 single-step rewriting: it now works in bound variable contexts. New is
  3035 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  3036 rewrite a different subterm than the original subst method, which is
  3037 still available as 'simplesubst'.
  3038 
  3039 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  3040 and quasi orders.
  3041 
  3042 * Provers/trancl.ML: new transitivity reasoner for transitive and
  3043 reflexive-transitive closure of relations.
  3044 
  3045 * Provers/blast.ML: new reference depth_limit to make blast's depth
  3046 limit (previously hard-coded with a value of 20) user-definable.
  3047 
  3048 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  3049 is peformed already.  Object-logics merely need to finish their
  3050 initial simpset configuration as before.  INCOMPATIBILITY.
  3051 
  3052 
  3053 *** HOL ***
  3054 
  3055 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3056 
  3057   syntax (epsilon)
  3058     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3059 
  3060 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3061 and x-symbol; use option '-m epsilon' to get it actually printed.
  3062 Moreover, the mathematically important symbolic identifier \<epsilon>
  3063 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3064 
  3065 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3066 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3067 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3068 support corresponding Isar calculations.
  3069 
  3070 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3071 instead of ":".
  3072 
  3073 * theory SetInterval: changed the syntax for open intervals:
  3074 
  3075   Old       New
  3076   {..n(}    {..<n}
  3077   {)n..}    {n<..}
  3078   {m..n(}   {m..<n}
  3079   {)m..n}   {m<..n}
  3080   {)m..n(}  {m<..<n}
  3081 
  3082 The old syntax is still supported but will disappear in the next
  3083 release.  For conversion use the following Emacs search and replace
  3084 patterns (these are not perfect but work quite well):
  3085 
  3086   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3087   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3088 
  3089 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3090 equalities in commutative rings; method 'algebra' provides a generic
  3091 interface.
  3092 
  3093 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3094 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3095 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3096 be a tuple pattern.
  3097 
  3098 Some new syntax forms are available:
  3099 
  3100   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3101   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3102   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3103   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3104 
  3105 The latter form "\<Sum>x < k. e" used to be based on a separate
  3106 function "Summation", which has been discontinued.
  3107 
  3108 * theory Finite_Set: in structured induction proofs, the insert case
  3109 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3110 (insert F x)'.
  3111 
  3112 * The 'refute' command has been extended to support a much larger
  3113 fragment of HOL, including axiomatic type classes, constdefs and
  3114 typedefs, inductive datatypes and recursion.
  3115 
  3116 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3117 Requires zChaff with proof generation to be installed.  See
  3118 HOL/ex/SAT_Examples.thy for examples.
  3119 
  3120 * Datatype induction via method 'induct' now preserves the name of the
  3121 induction variable. For example, when proving P(xs::'a list) by
  3122 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3123 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3124 in unstructured proof scripts.
  3125 
  3126 * Reworked implementation of records.  Improved scalability for
  3127 records with many fields, avoiding performance problems for type
  3128 inference. Records are no longer composed of nested field types, but
  3129 of nested extension types. Therefore the record type only grows linear
  3130 in the number of extensions and not in the number of fields.  The
  3131 top-level (users) view on records is preserved.  Potential
  3132 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3133 old record representation. The type generated for a record is called
  3134 <record_name>_ext_type.
  3135 
  3136 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3137 proofs triggered by a record definition or a simproc (if
  3138 quick_and_dirty is enabled).  Definitions of large records can take
  3139 quite long.
  3140 
  3141 New simproc record_upd_simproc for simplification of multiple record
  3142 updates enabled by default.  Moreover, trivial updates are also
  3143 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3144 occasionally, since simplification is more powerful by default.
  3145 
  3146 * typedef: proper support for polymorphic sets, which contain extra
  3147 type-variables in the term.
  3148 
  3149 * Simplifier: automatically reasons about transitivity chains
  3150 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3151 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3152 old proofs break occasionally as simplification may now solve more
  3153 goals than previously.
  3154 
  3155 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3156 present.  Works for all partial orders (class "order"), in particular
  3157 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3158 just like y <= x.
  3159 
  3160 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3161 bound variable or a constant then the let is unfolded.  Otherwise
  3162 first a is simplified to b, and then f b is simplified to g. If
  3163 possible we abstract b from g arriving at "let x = b in h x",
  3164 otherwise we unfold the let and arrive at g.  The simproc can be
  3165 enabled/disabled by the reference use_let_simproc.  Potential
  3166 INCOMPATIBILITY since simplification is more powerful by default.
  3167 
  3168 * Classical reasoning: the meson method now accepts theorems as arguments.
  3169 
  3170 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3171 jobs to provide advice on the provability of subgoals.
  3172 
  3173 * Theory OrderedGroup and Ring_and_Field: various additions and
  3174 improvements to faciliate calculations involving equalities and
  3175 inequalities.
  3176 
  3177 The following theorems have been eliminated or modified
  3178 (INCOMPATIBILITY):
  3179 
  3180   abs_eq             now named abs_of_nonneg
  3181   abs_of_ge_0        now named abs_of_nonneg
  3182   abs_minus_eq       now named abs_of_nonpos
  3183   imp_abs_id         now named abs_of_nonneg
  3184   imp_abs_neg_id     now named abs_of_nonpos
  3185   mult_pos           now named mult_pos_pos
  3186   mult_pos_le        now named mult_nonneg_nonneg
  3187   mult_pos_neg_le    now named mult_nonneg_nonpos
  3188   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3189   mult_neg           now named mult_neg_neg
  3190   mult_neg_le        now named mult_nonpos_nonpos
  3191 
  3192 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3193      
  3194      zero_le_square
  3195      not_square_less_zero 
  3196 
  3197   The following lemmas have been deleted from Real/RealPow:
  3198   
  3199      realpow_zero_zero
  3200      realpow_two
  3201      realpow_less
  3202      zero_le_power
  3203      realpow_two_le
  3204      abs_realpow_two
  3205      realpow_two_abs     
  3206 
  3207 * Theory Parity: added rules for simplifying exponents.
  3208 
  3209 * Theory List:
  3210 
  3211 The following theorems have been eliminated or modified
  3212 (INCOMPATIBILITY):
  3213 
  3214   list_all_Nil       now named list_all.simps(1)
  3215   list_all_Cons      now named list_all.simps(2)
  3216   list_all_conv      now named list_all_iff
  3217   set_mem_eq         now named mem_iff
  3218 
  3219 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3220 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3221 
  3222 
  3223 *** HOL-Complex ***
  3224 
  3225 * Theory RealDef: better support for embedding natural numbers and
  3226 integers in the reals.
  3227 
  3228 The following theorems have been eliminated or modified
  3229 (INCOMPATIBILITY):
  3230 
  3231   exp_ge_add_one_self  now requires no hypotheses
  3232   real_of_int_add      reversed direction of equality (use [symmetric])
  3233   real_of_int_minus    reversed direction of equality (use [symmetric])
  3234   real_of_int_diff     reversed direction of equality (use [symmetric])
  3235   real_of_int_mult     reversed direction of equality (use [symmetric])
  3236 
  3237 * Theory RComplete: expanded support for floor and ceiling functions.
  3238 
  3239 * Theory Ln is new, with properties of the natural logarithm
  3240 
  3241 * Hyperreal: There is a new type constructor "star" for making
  3242 nonstandard types.  The old type names are now type synonyms:
  3243 
  3244   hypreal = real star
  3245   hypnat = nat star
  3246   hcomplex = complex star
  3247 
  3248 * Hyperreal: Many groups of similarly-defined constants have been
  3249 replaced by polymorphic versions (INCOMPATIBILITY):
  3250 
  3251   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3252 
  3253   starset      <-- starsetNat, starsetC
  3254   *s*          <-- *sNat*, *sc*
  3255   starset_n    <-- starsetNat_n, starsetC_n
  3256   *sn*         <-- *sNatn*, *scn*
  3257   InternalSets <-- InternalNatSets, InternalCSets
  3258 
  3259   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3260   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3261   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3262   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3263   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3264 
  3265 * Hyperreal: Many type-specific theorems have been removed in favor of
  3266 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3267 
  3268   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3269   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3270   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3271   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3272   right_minus <-- hypreal_add_minus
  3273   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3274   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3275   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3276   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3277   mult_1_right <-- hcomplex_mult_one_right
  3278   mult_zero_left <-- hcomplex_mult_zero_left
  3279   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3280   right_distrib <-- hypnat_add_mult_distrib2
  3281   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3282   right_inverse <-- hypreal_mult_inverse
  3283   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3284   order_refl <-- {hypreal,hypnat}_le_refl
  3285   order_trans <-- {hypreal,hypnat}_le_trans
  3286   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3287   order_less_le <-- {hypreal,hypnat}_less_le
  3288   linorder_linear <-- {hypreal,hypnat}_le_linear
  3289   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3290   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3291   add_nonneg_nonneg <-- hypreal_le_add_order
  3292 
  3293 * Hyperreal: Separate theorems having to do with type-specific
  3294 versions of constants have been merged into theorems that apply to the
  3295 new polymorphic constants (INCOMPATIBILITY):
  3296 
  3297   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3298   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3299   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3300   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3301   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3302   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3303   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3304   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3305   STAR_diff <-- {STAR,STARC}_diff
  3306   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3307     STARC_hcomplex_of_complex}_image_subset
  3308   starset_n_Un <-- starset{Nat,C}_n_Un
  3309   starset_n_Int <-- starset{Nat,C}_n_Int
  3310   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3311   starset_n_diff <-- starset{Nat,C}_n_diff
  3312   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3313   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3314   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3315   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3316   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3317   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3318   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3319   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3320   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3321   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3322   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3323   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3324   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3325   starfun_diff <-- starfun{C,RC,CR}_diff
  3326   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3327   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3328   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3329   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3330   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3331   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3332   starfun_Id <-- starfunC_Id
  3333   starfun_approx <-- starfun{Nat,CR}_approx
  3334   starfun_capprox <-- starfun{C,RC}_capprox
  3335   starfun_abs <-- starfunNat_rabs
  3336   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3337   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3338   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3339   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3340   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3341   starfun_add_approx <-- starfunCR_add_approx
  3342   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3343   starfun_divide <-- starfun{C,CR,RC}_divide
  3344   starfun_n <-- starfun{Nat,C}_n
  3345   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3346   starfun_n_add <-- starfun{Nat,C}_n_add
  3347   starfun_n_add_minus <-- starfunNat_n_add_minus
  3348   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3349   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3350   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3351 
  3352   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3353   star_n_minus <-- {hypreal,hcomplex}_minus
  3354   star_n_diff <-- {hypreal,hcomplex}_diff
  3355   star_n_mult <-- {hypreal,hcomplex}_mult
  3356   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3357   star_n_le <-- {hypreal,hypnat}_le
  3358   star_n_less <-- {hypreal,hypnat}_less
  3359   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3360   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3361   star_n_abs <-- hypreal_hrabs
  3362   star_n_divide <-- hcomplex_divide
  3363 
  3364   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3365   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3366   star_of_diff <-- hypreal_of_real_diff
  3367   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3368   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3369   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3370   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3371   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3372   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3373   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3374   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3375   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3376   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3377   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3378   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3379   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3380   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3381   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3382   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3383   star_of_power <-- hypreal_of_real_power
  3384   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3385 
  3386 * Hyperreal: new method "transfer" that implements the transfer
  3387 principle of nonstandard analysis. With a subgoal that mentions
  3388 nonstandard types like "'a star", the command "apply transfer"
  3389 replaces it with an equivalent one that mentions only standard types.
  3390 To be successful, all free variables must have standard types; non-
  3391 standard variables must have explicit universal quantifiers.
  3392 
  3393 * Hyperreal: A theory of Taylor series.
  3394 
  3395 
  3396 *** HOLCF ***
  3397 
  3398 * Discontinued special version of 'constdefs' (which used to support
  3399 continuous functions) in favor of the general Pure one with full
  3400 type-inference.
  3401 
  3402 * New simplification procedure for solving continuity conditions; it
  3403 is much faster on terms with many nested lambda abstractions (cubic
  3404 instead of exponential time).
  3405 
  3406 * New syntax for domain package: selector names are now optional.
  3407 Parentheses should be omitted unless argument is lazy, for example:
  3408 
  3409   domain 'a stream = cons "'a" (lazy "'a stream")
  3410 
  3411 * New command 'fixrec' for defining recursive functions with pattern
  3412 matching; defining multiple functions with mutual recursion is also
  3413 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3414 sinr, or any data constructor defined by the domain package. The given
  3415 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3416 syntax and examples.
  3417 
  3418 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3419 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3420 but the proof obligation additionally includes an admissibility
  3421 requirement. The packages generate instances of class cpo or pcpo,
  3422 with continuity and strictness theorems for Rep and Abs.
  3423 
  3424 * HOLCF: Many theorems have been renamed according to a more standard naming
  3425 scheme (INCOMPATIBILITY):
  3426 
  3427   foo_inject:  "foo$x = foo$y ==> x = y"
  3428   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3429   foo_less:    "(foo$x << foo$y) = (x << y)"
  3430   foo_strict:  "foo$UU = UU"
  3431   foo_defined: "... ==> foo$x ~= UU"
  3432   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3433 
  3434 
  3435 *** ZF ***
  3436 
  3437 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3438 including the First Isomorphism Theorem (on quotienting by the kernel
  3439 of a homomorphism).
  3440 
  3441 * ZF/Simplifier: install second copy of type solver that actually
  3442 makes use of TC rules declared to Isar proof contexts (or locales);
  3443 the old version is still required for ML proof scripts.
  3444 
  3445 
  3446 *** Cube ***
  3447 
  3448 * Converted to Isar theory format; use locales instead of axiomatic
  3449 theories.
  3450 
  3451 
  3452 *** ML ***
  3453 
  3454 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3455 for ||>, ||>>, |>>,
  3456 
  3457 * Pure/library.ML no longer defines its own option datatype, but uses
  3458 that of the SML basis, which has constructors NONE and SOME instead of
  3459 None and Some, as well as exception Option.Option instead of OPTION.
  3460 The functions the, if_none, is_some, is_none have been adapted
  3461 accordingly, while Option.map replaces apsome.
  3462 
  3463 * Pure/library.ML: the exception LIST has been given up in favour of
  3464 the standard exceptions Empty and Subscript, as well as
  3465 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3466 superceded by the standard hd and tl functions etc.
  3467 
  3468 A number of basic list functions are no longer exported to the ML
  3469 toplevel, as they are variants of predefined functions.  The following
  3470 suggests how one can translate existing code:
  3471 
  3472     rev_append xs ys = List.revAppend (xs, ys)
  3473     nth_elem (i, xs) = List.nth (xs, i)
  3474     last_elem xs = List.last xs
  3475     flat xss = List.concat xss
  3476     seq fs = List.app fs
  3477     partition P xs = List.partition P xs
  3478     mapfilter f xs = List.mapPartial f xs
  3479 
  3480 * Pure/library.ML: several combinators for linear functional
  3481 transformations, notably reverse application and composition:
  3482 
  3483   x |> f                f #> g
  3484   (x, y) |-> f          f #-> g
  3485 
  3486 * Pure/library.ML: introduced/changed precedence of infix operators:
  3487 
  3488   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3489   infix 2 ?;
  3490   infix 3 o oo ooo oooo;
  3491   infix 4 ~~ upto downto;
  3492 
  3493 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3494 infix operators.
  3495 
  3496 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3497 fold_map support linear functional transformations and nesting.  For
  3498 example:
  3499 
  3500   fold f [x1, ..., xN] y =
  3501     y |> f x1 |> ... |> f xN
  3502 
  3503   (fold o fold) f [xs1, ..., xsN] y =
  3504     y |> fold f xs1 |> ... |> fold f xsN
  3505 
  3506   fold f [x1, ..., xN] =
  3507     f x1 #> ... #> f xN
  3508 
  3509   (fold o fold) f [xs1, ..., xsN] =
  3510     fold f xs1 #> ... #> fold f xsN
  3511 
  3512 * Pure/library.ML: the following selectors on type 'a option are
  3513 available:
  3514 
  3515   the:               'a option -> 'a  (*partial*)
  3516   these:             'a option -> 'a  where 'a = 'b list
  3517   the_default: 'a -> 'a option -> 'a
  3518   the_list:          'a option -> 'a list
  3519 
  3520 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3521 basic operations for association lists, following natural argument
  3522 order; moreover the explicit equality predicate passed here avoids
  3523 potentially expensive polymorphic runtime equality checks.
  3524 The old functions may be expressed as follows:
  3525 
  3526   assoc = uncurry (AList.lookup (op =))
  3527   assocs = these oo AList.lookup (op =)
  3528   overwrite = uncurry (AList.update (op =)) o swap
  3529 
  3530 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3531 
  3532   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3533   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3534 
  3535 replacing make_keylist and keyfilter (occassionally used)
  3536 Naive rewrites:
  3537 
  3538   make_keylist = AList.make
  3539   keyfilter = AList.find (op =)
  3540 
  3541 * eq_fst and eq_snd now take explicit equality parameter, thus
  3542   avoiding eqtypes. Naive rewrites:
  3543 
  3544     eq_fst = eq_fst (op =)
  3545     eq_snd = eq_snd (op =)
  3546 
  3547 * Removed deprecated apl and apr (rarely used).
  3548   Naive rewrites:
  3549 
  3550     apl (n, op) =>>= curry op n
  3551     apr (op, m) =>>= fn n => op (n, m)
  3552 
  3553 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3554 provides a reasonably efficient light-weight implementation of sets as
  3555 lists.
  3556 
  3557 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3558 few new operations; existing lookup and update are now curried to
  3559 follow natural argument order (for use with fold etc.);
  3560 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3561 
  3562 * Pure/General: output via the Isabelle channels of
  3563 writeln/warning/error etc. is now passed through Output.output, with a
  3564 hook for arbitrary transformations depending on the print_mode
  3565 (cf. Output.add_mode -- the first active mode that provides a output
  3566 function wins).  Already formatted output may be embedded into further
  3567 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3568 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3569 accommodate easy composition of diagnostic messages etc.  Programmers
  3570 rarely need to care about Output.output or Output.raw at all, with
  3571 some notable exceptions: Output.output is required when bypassing the
  3572 standard channels (writeln etc.), or in token translations to produce
  3573 properly formatted results; Output.raw is required when capturing
  3574 already output material that will eventually be presented to the user
  3575 a second time.  For the default print mode, both Output.output and
  3576 Output.raw have no effect.
  3577 
  3578 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3579 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3580 cumulative results are displayed at the end of a batch session.
  3581 
  3582 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3583 replaced by File.platform_path and File.shell_path (with appropriate
  3584 hooks).  This provides a clean interface for unusual systems where the
  3585 internal and external process view of file names are different.
  3586 
  3587 * Pure: more efficient orders for basic syntactic entities: added
  3588 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3589 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3590 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3591 orders now -- potential INCOMPATIBILITY for code that depends on a
  3592 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3593 Library.sort_strings on result).
  3594 
  3595 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3596 fold_types traverse types/terms from left to right, observing natural
  3597 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3598 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3599 
  3600 * Pure: name spaces have been refined, with significant changes of the
  3601 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3602 to extern(_table).  The plain name entry path is superceded by a
  3603 general 'naming' context, which also includes the 'policy' to produce
  3604 a fully qualified name and external accesses of a fully qualified
  3605 name; NameSpace.extend is superceded by context dependent
  3606 Sign.declare_name.  Several theory and proof context operations modify
  3607 the naming context.  Especially note Theory.restore_naming and
  3608 ProofContext.restore_naming to get back to a sane state; note that
  3609 Theory.add_path is no longer sufficient to recover from
  3610 Theory.absolute_path in particular.
  3611 
  3612 * Pure: new flags short_names (default false) and unique_names
  3613 (default true) for controlling output of qualified names.  If
  3614 short_names is set, names are printed unqualified.  If unique_names is
  3615 reset, the name prefix is reduced to the minimum required to achieve
  3616 the original result when interning again, even if there is an overlap
  3617 with earlier declarations.
  3618 
  3619 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3620 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3621 (useful for printing error messages).  INCOMPATIBILITY.
  3622 
  3623 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3624 Theory.theory are now identified, referring to the universal
  3625 Context.theory (see Pure/context.ML).  Actual signature and theory
  3626 content is managed as theory data.  The old code and interfaces were
  3627 spread over many files and structures; the new arrangement introduces
  3628 considerable INCOMPATIBILITY to gain more clarity:
  3629 
  3630   Context -- theory management operations (name, identity, inclusion,
  3631     parents, ancestors, merge, etc.), plus generic theory data;
  3632 
  3633   Sign -- logical signature and syntax operations (declaring consts,
  3634     types, etc.), plus certify/read for common entities;
  3635 
  3636   Theory -- logical theory operations (stating axioms, definitions,
  3637     oracles), plus a copy of logical signature operations (consts,
  3638     types, etc.); also a few basic management operations (Theory.copy,
  3639     Theory.merge, etc.)
  3640 
  3641 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3642 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3643 for convenience -- they merely return the theory.
  3644 
  3645 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3646 
  3647 * Pure: the Isar proof context type is already defined early in Pure
  3648 as Context.proof (note that ProofContext.context and Proof.context are
  3649 aliases, where the latter is the preferred name).  This enables other
  3650 Isabelle components to refer to that type even before Isar is present.
  3651 
  3652 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3653 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3654 any of these kinds.  For example, Sign.intern typeK is now
  3655 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3656 Theory.hide_types.  Also note that former
  3657 Theory.hide_classes/types/consts are now
  3658 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3659 internalize their arguments!  INCOMPATIBILITY.
  3660 
  3661 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3662 datatype thmref (with constructors Name and NameSelection) instead of
  3663 plain string -- INCOMPATIBILITY;
  3664 
  3665 * Pure: cases produced by proof methods specify options, where NONE
  3666 means to remove case bindings -- INCOMPATIBILITY in
  3667 (RAW_)METHOD_CASES.
  3668 
  3669 * Pure: the following operations retrieve axioms or theorems from a
  3670 theory node or theory hierarchy, respectively:
  3671 
  3672   Theory.axioms_of: theory -> (string * term) list
  3673   Theory.all_axioms_of: theory -> (string * term) list
  3674   PureThy.thms_of: theory -> (string * thm) list
  3675   PureThy.all_thms_of: theory -> (string * thm) list
  3676 
  3677 * Pure: print_tac now outputs the goal through the trace channel.
  3678 
  3679 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3680 Reference Toplevel.debug (default false) controls detailed printing
  3681 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3682 controls execution profiling -- set to 1 for time and 2 for space
  3683 (both increase the runtime).
  3684 
  3685 * Isar session: The initial use of ROOT.ML is now always timed,
  3686 i.e. the log will show the actual process times, in contrast to the
  3687 elapsed wall-clock time that the outer shell wrapper produces.
  3688 
  3689 * Simplifier: improved handling of bound variables (nameless
  3690 representation, avoid allocating new strings).  Simprocs that invoke
  3691 the Simplifier recursively should use Simplifier.inherit_bounds to
  3692 avoid local name clashes.  Failure to do so produces warnings
  3693 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3694 for further details.
  3695 
  3696 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3697 bindings for all theorems stored within a given theory; this may help
  3698 in porting non-Isar theories to Isar ones, while keeping ML proof
  3699 scripts for the time being.
  3700 
  3701 * ML operator HTML.with_charset specifies the charset begin used for
  3702 generated HTML files.  For example:
  3703 
  3704   HTML.with_charset "utf-8" use_thy "Hebrew";
  3705   HTML.with_charset "utf-8" use_thy "Chinese";
  3706 
  3707 
  3708 *** System ***
  3709 
  3710 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3711 isabelle, isatool etc.).
  3712 
  3713 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3714 isatool doc, isatool mkdir, display_drafts etc.).
  3715 
  3716 * isatool usedir: option -f allows specification of the ML file to be
  3717 used by Isabelle; default is ROOT.ML.
  3718 
  3719 * New isatool version outputs the version identifier of the Isabelle
  3720 distribution being used.
  3721 
  3722 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3723 (containing Boolean satisfiability problems) into Isabelle/HOL
  3724 theories.
  3725 
  3726 
  3727 
  3728 New in Isabelle2004 (April 2004)
  3729 --------------------------------
  3730 
  3731 *** General ***
  3732 
  3733 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3734   Replaces linorder.ML.
  3735 
  3736 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3737   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3738   (\<a>...\<z>), are now considered normal letters, and can therefore
  3739   be used anywhere where an ASCII letter (a...zA...Z) has until
  3740   now. COMPATIBILITY: This obviously changes the parsing of some
  3741   terms, especially where a symbol has been used as a binder, say
  3742   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3743   as an identifier.  Fix it by inserting a space around former
  3744   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3745   existing theory and ML files.
  3746 
  3747 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3748 
  3749 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3750   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3751   a normal (but invisible) letter. For multiple letter subscripts repeat
  3752   \<^isub> like this: x\<^isub>1\<^isub>2.
  3753 
  3754 * Pure: There are now sub-/superscripts that can span more than one
  3755   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3756   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3757   superscript. The new control characters are not identifier parts.
  3758 
  3759 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3760   content of "..." to the latex file instead of \isacntrl... . The "..."
  3761   may consist of any printable characters excluding the end bracket >.
  3762 
  3763 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3764   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3765   declare constants "final", which prevents their being given a definition
  3766   later.  It is useful for constants whose behaviour is fixed axiomatically
  3767   rather than definitionally, such as the meta-logic connectives.
  3768 
  3769 * Pure: 'instance' now handles general arities with general sorts
  3770   (i.e. intersections of classes),
  3771 
  3772 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3773   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3774   It can be changed to alter the colors/layout of generated pages.
  3775 
  3776 
  3777 *** Isar ***
  3778 
  3779 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3780   cut_tac, subgoal_tac and thin_tac:
  3781   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3782     locales are no longer forced to write Isar proof scripts.
  3783     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3784     emulations.
  3785   - INCOMPATIBILITY: names of variables to be instantiated may no
  3786     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3787     This is consistent with the instantiation attribute "where".
  3788 
  3789 * Attributes "where" and "of":
  3790   - Now take type variables of instantiated theorem into account when reading
  3791     the instantiation string.  This fixes a bug that caused instantiated
  3792     theorems to have too special types in some circumstances.
  3793   - "where" permits explicit instantiations of type variables.
  3794 
  3795 * Calculation commands "moreover" and "also" no longer interfere with
  3796   current facts ("this"), admitting arbitrary combinations with "then"
  3797   and derived forms.
  3798 
  3799 * Locales:
  3800   - Goal statements involving the context element "includes" no longer
  3801     generate theorems with internal delta predicates (those ending on
  3802     "_axioms") in the premise.
  3803     Resolve particular premise with <locale>.intro to obtain old form.
  3804   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3805     specification and "includes" elements in goal statement.
  3806   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3807     [intro?] and [elim?] (respectively) by default.
  3808   - Experimental command for instantiation of locales in proof contexts:
  3809         instantiate <label>[<attrs>]: <loc>
  3810     Instantiates locale <loc> and adds all its theorems to the current context
  3811     taking into account their attributes.  Label and attrs are optional
  3812     modifiers, like in theorem declarations.  If present, names of
  3813     instantiated theorems are qualified with <label>, and the attributes
  3814     <attrs> are applied after any attributes these theorems might have already.
  3815       If the locale has assumptions, a chained fact of the form
  3816     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3817     are derived.  The command does not support old-style locales declared
  3818     with "locale (open)".
  3819       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3820 
  3821 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3822   (Isar) contexts.
  3823 
  3824 
  3825 *** HOL ***
  3826 
  3827 * Proof import: new image HOL4 contains the imported library from
  3828   the HOL4 system with about 2500 theorems. It is imported by
  3829   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3830   can be used like any other Isabelle image.  See
  3831   HOL/Import/HOL/README for more information.
  3832 
  3833 * Simplifier:
  3834   - Much improved handling of linear and partial orders.
  3835     Reasoners for linear and partial orders are set up for type classes
  3836     "linorder" and "order" respectively, and are added to the default simpset
  3837     as solvers.  This means that the simplifier can build transitivity chains
  3838     to solve goals from the assumptions.
  3839   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3840     of blast or auto after simplification become unnecessary because the goal
  3841     is solved by simplification already.
  3842 
  3843 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3844     all proved in axiomatic type classes for semirings, rings and fields.
  3845 
  3846 * Numerics:
  3847   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3848     now formalized using the Ring_and_Field theory mentioned above.
  3849   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3850     than before, because now they are set up once in a generic manner.
  3851   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3852     Look for the general versions in Ring_and_Field (and Power if they concern
  3853     exponentiation).
  3854 
  3855 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3856 
  3857 * Records:
  3858   - Record types are now by default printed with their type abbreviation
  3859     instead of the list of all field types. This can be configured via
  3860     the reference "print_record_type_abbr".
  3861   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3862     (not enabled by default).
  3863   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3864     EX x. x = sel r to True (not enabled by default).
  3865   - Tactic "record_split_simp_tac" to split and simplify records added.
  3866 
  3867 * 'specification' command added, allowing for definition by
  3868   specification.  There is also an 'ax_specification' command that
  3869   introduces the new constants axiomatically.
  3870 
  3871 * arith(_tac) is now able to generate counterexamples for reals as well.
  3872 
  3873 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3874 
  3875 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3876   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3877 
  3878 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3879   matrix theory to linear programming.
  3880 
  3881 * Unions and Intersections:
  3882   The latex output syntax of UN and INT has been changed
  3883   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3884   i.e. the index formulae has become a subscript.
  3885   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3886 
  3887 * Unions and Intersections over Intervals:
  3888   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3889   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3890   like in normal math, and corresponding versions for < and for intersection.
  3891 
  3892 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3893   lexicographic dictonary ordering has been added as "lexord".
  3894 
  3895 * ML: the legacy theory structures Int and List have been removed. They had
  3896   conflicted with ML Basis Library structures having the same names.
  3897 
  3898 * 'refute' command added to search for (finite) countermodels.  Only works
  3899   for a fragment of HOL.  The installation of an external SAT solver is
  3900   highly recommended.  See "HOL/Refute.thy" for details.
  3901 
  3902 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3903   formulae under an assignment of free variables to random values.
  3904   In contrast to 'refute', it can deal with inductive datatypes,
  3905   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3906   for examples.
  3907 
  3908 
  3909 *** HOLCF ***
  3910 
  3911 * Streams now come with concatenation and are part of the HOLCF image
  3912 
  3913 
  3914 
  3915 New in Isabelle2003 (May 2003)
  3916 ------------------------------
  3917 
  3918 *** General ***
  3919 
  3920 * Provers/simplifier:
  3921 
  3922   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3923     Assumptions are now subject to complete mutual simplification,
  3924     not just from left to right. The simplifier now preserves
  3925     the order of assumptions.
  3926 
  3927     Potential INCOMPATIBILITY:
  3928 
  3929     -- simp sometimes diverges where the old version did
  3930        not, e.g. invoking simp on the goal
  3931 
  3932         [| P (f x); y = x; f x = f y |] ==> Q
  3933 
  3934        now gives rise to the infinite reduction sequence
  3935 
  3936         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3937 
  3938        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3939        kind of problem.
  3940 
  3941     -- Tactics combining classical reasoner and simplification (such as auto)
  3942        are also affected by this change, because many of them rely on
  3943        simp. They may sometimes diverge as well or yield a different numbers
  3944        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3945        in case of problems. Sometimes subsequent calls to the classical
  3946        reasoner will fail because a preceeding call to the simplifier too
  3947        eagerly simplified the goal, e.g. deleted redundant premises.
  3948 
  3949   - The simplifier trace now shows the names of the applied rewrite rules
  3950 
  3951   - You can limit the number of recursive invocations of the simplifier
  3952     during conditional rewriting (where the simplifie tries to solve the
  3953     conditions before applying the rewrite rule):
  3954     ML "simp_depth_limit := n"
  3955     where n is an integer. Thus you can force termination where previously
  3956     the simplifier would diverge.
  3957 
  3958   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3959 
  3960   - No longer aborts on failed congruence proof.  Instead, the
  3961     congruence is ignored.
  3962 
  3963 * Pure: New generic framework for extracting programs from constructive
  3964   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3965   as HOL/Extraction for some case studies.
  3966 
  3967 * Pure: The main goal of the proof state is no longer shown by default, only
  3968 the subgoals. This behaviour is controlled by a new flag.
  3969    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3970 (ML: Proof.show_main_goal).
  3971 
  3972 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3973 rules whose conclusion matches subgoal 1:
  3974       PG menu: Isabelle/Isar -> Show me -> matching rules
  3975 The rules are ordered by how closely they match the subgoal.
  3976 In particular, rules that solve a subgoal outright are displayed first
  3977 (or rather last, the way they are printed).
  3978 (ML: ProofGeneral.print_intros())
  3979 
  3980 * Pure: New flag trace_unify_fail causes unification to print
  3981 diagnostic information (PG: in trace buffer) when it fails. This is
  3982 useful for figuring out why single step proofs like rule, erule or
  3983 assumption failed.
  3984 
  3985 * Pure: Locale specifications now produce predicate definitions
  3986 according to the body of text (covering assumptions modulo local
  3987 definitions); predicate "loc_axioms" covers newly introduced text,
  3988 while "loc" is cumulative wrt. all included locale expressions; the
  3989 latter view is presented only on export into the global theory
  3990 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3991 on the old view without predicates;
  3992 
  3993 * Pure: predefined locales "var" and "struct" are useful for sharing
  3994 parameters (as in CASL, for example); just specify something like
  3995 ``var x + var y + struct M'' as import;
  3996 
  3997 * Pure: improved thms_containing: proper indexing of facts instead of
  3998 raw theorems; check validity of results wrt. current name space;
  3999 include local facts of proof configuration (also covers active
  4000 locales), cover fixed variables in index; may use "_" in term
  4001 specification; an optional limit for the number of printed facts may
  4002 be given (the default is 40);
  4003 
  4004 * Pure: disallow duplicate fact bindings within new-style theory files
  4005 (batch-mode only);
  4006 
  4007 * Provers: improved induct method: assumptions introduced by case
  4008 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  4009 the goal statement); "foo" still refers to all facts collectively;
  4010 
  4011 * Provers: the function blast.overloaded has been removed: all constants
  4012 are regarded as potentially overloaded, which improves robustness in exchange
  4013 for slight decrease in efficiency;
  4014 
  4015 * Provers/linorder: New generic prover for transitivity reasoning over
  4016 linear orders.  Note: this prover is not efficient!
  4017 
  4018 * Isar: preview of problems to finish 'show' now produce an error
  4019 rather than just a warning (in interactive mode);
  4020 
  4021 
  4022 *** HOL ***
  4023 
  4024 * arith(_tac)
  4025 
  4026  - Produces a counter example if it cannot prove a goal.
  4027    Note that the counter example may be spurious if the goal is not a formula
  4028    of quantifier-free linear arithmetic.
  4029    In ProofGeneral the counter example appears in the trace buffer.
  4030 
  4031  - Knows about div k and mod k where k is a numeral of type nat or int.
  4032 
  4033  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  4034    linear arithmetic fails. This takes account of quantifiers and divisibility.
  4035    Presburger arithmetic can also be called explicitly via presburger(_tac).
  4036 
  4037 * simp's arithmetic capabilities have been enhanced a bit: it now
  4038 takes ~= in premises into account (by performing a case split);
  4039 
  4040 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  4041 are distributed over a sum of terms;
  4042 
  4043 * New tactic "trans_tac" and method "trans" instantiate
  4044 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  4045 "<=", "<" and "=").
  4046 
  4047 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  4048 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  4049 
  4050 * 'typedef' command has new option "open" to suppress the set
  4051 definition;
  4052 
  4053 * functions Min and Max on finite sets have been introduced (theory
  4054 Finite_Set);
  4055 
  4056 * attribute [symmetric] now works for relations as well; it turns
  4057 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4058 
  4059 * induct over a !!-quantified statement (say !!x1..xn):
  4060   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4061 
  4062 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4063 %x. None. Warning: empty_def now refers to the previously hidden definition
  4064 of the empty set.
  4065 
  4066 * Algebra: formalization of classical algebra.  Intended as base for
  4067 any algebraic development in Isabelle.  Currently covers group theory
  4068 (up to Sylow's theorem) and ring theory (Universal Property of
  4069 Univariate Polynomials).  Contributions welcome;
  4070 
  4071 * GroupTheory: deleted, since its material has been moved to Algebra;
  4072 
  4073 * Complex: new directory of the complex numbers with numeric constants,
  4074 nonstandard complex numbers, and some complex analysis, standard and
  4075 nonstandard (Jacques Fleuriot);
  4076 
  4077 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4078 
  4079 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4080 Fleuriot);
  4081 
  4082 * Real/HahnBanach: updated and adapted to locales;
  4083 
  4084 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4085 Gray and Kramer);
  4086 
  4087 * UNITY: added the Meier-Sanders theory of progress sets;
  4088 
  4089 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4090 as abstract algorithms, instantiated to the JVM;
  4091 
  4092 * Bali: Java source language formalization. Type system, operational
  4093 semantics, axiomatic semantics. Supported language features:
  4094 classes, interfaces, objects,virtual methods, static methods,
  4095 static/instance fields, arrays, access modifiers, definite
  4096 assignment, exceptions.
  4097 
  4098 
  4099 *** ZF ***
  4100 
  4101 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4102 universe, etc.);
  4103 
  4104 * Main ZF: virtually all theories converted to new-style format;
  4105 
  4106 
  4107 *** ML ***
  4108 
  4109 * Pure: Tactic.prove provides sane interface for internal proofs;
  4110 omits the infamous "standard" operation, so this is more appropriate
  4111 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4112 
  4113 * Pure: improved error reporting of simprocs;
  4114 
  4115 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4116 up simprocs;
  4117 
  4118 
  4119 *** Document preparation ***
  4120 
  4121 * uses \par instead of \\ for line breaks in theory text. This may
  4122 shift some page breaks in large documents. To get the old behaviour
  4123 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4124 
  4125 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4126 other packages
  4127 
  4128 * \<euro> now needs package babel/greek instead of marvosym (which
  4129 broke \Rightarrow)
  4130 
  4131 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4132 textcomp package)
  4133 
  4134 
  4135 
  4136 New in Isabelle2002 (March 2002)
  4137 --------------------------------
  4138 
  4139 *** Document preparation ***
  4140 
  4141 * greatly simplified document preparation setup, including more
  4142 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4143 instructive isatool mkdir; users should basically be able to get
  4144 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4145 users may run a separate document processing stage manually like this:
  4146 "isatool usedir -D output HOL Test && isatool document Test/output";
  4147 
  4148 * theory dependency graph may now be incorporated into documents;
  4149 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4150 with \includegraphics of LaTeX;
  4151 
  4152 * proper spacing of consecutive markup elements, especially text
  4153 blocks after section headings;
  4154 
  4155 * support bold style (for single symbols only), input syntax is like
  4156 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4157 
  4158 * \<bullet> is now output as bold \cdot by default, which looks much
  4159 better in printed text;
  4160 
  4161 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4162 note that these symbols are currently unavailable in Proof General /
  4163 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4164 
  4165 * isatool latex no longer depends on changed TEXINPUTS, instead
  4166 isatool document copies the Isabelle style files to the target
  4167 location;
  4168 
  4169 
  4170 *** Isar ***
  4171 
  4172 * Pure/Provers: improved proof by cases and induction;
  4173   - 'case' command admits impromptu naming of parameters (such as
  4174     "case (Suc n)");
  4175   - 'induct' method divinates rule instantiation from the inductive
  4176     claim; no longer requires excessive ?P bindings for proper
  4177     instantiation of cases;
  4178   - 'induct' method properly enumerates all possibilities of set/type
  4179     rules; as a consequence facts may be also passed through *type*
  4180     rules without further ado;
  4181   - 'induct' method now derives symbolic cases from the *rulified*
  4182     rule (before it used to rulify cases stemming from the internal
  4183     atomized version); this means that the context of a non-atomic
  4184     statement becomes is included in the hypothesis, avoiding the
  4185     slightly cumbersome show "PROP ?case" form;
  4186   - 'induct' may now use elim-style induction rules without chaining
  4187     facts, using ``missing'' premises from the goal state; this allows
  4188     rules stemming from inductive sets to be applied in unstructured
  4189     scripts, while still benefitting from proper handling of non-atomic
  4190     statements; NB: major inductive premises need to be put first, all
  4191     the rest of the goal is passed through the induction;
  4192   - 'induct' proper support for mutual induction involving non-atomic
  4193     rule statements (uses the new concept of simultaneous goals, see
  4194     below);
  4195   - append all possible rule selections, but only use the first
  4196     success (no backtracking);
  4197   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4198   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4199   - added 'print_induct_rules' (covered by help item in recent Proof
  4200     General versions);
  4201   - moved induct/cases attributes to Pure, methods to Provers;
  4202   - generic method setup instantiated for FOL and HOL;
  4203 
  4204 * Pure: support multiple simultaneous goal statements, for example
  4205 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4206 meta-level mechanism, this acts as if several individual goals had
  4207 been stated separately; in particular common proof methods need to be
  4208 repeated in order to cover all claims; note that a single elimination
  4209 step is *not* sufficient to establish the two conjunctions, so this
  4210 fails:
  4211 
  4212   assume "A & B" then have A and B ..   (*".." fails*)
  4213 
  4214 better use "obtain" in situations as above; alternative refer to
  4215 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4216 
  4217 * Pure: proper integration with ``locales''; unlike the original
  4218 version by Florian Kammller, Isar locales package high-level proof
  4219 contexts rather than raw logical ones (e.g. we admit to include
  4220 attributes everywhere); operations on locales include merge and
  4221 rename; support for implicit arguments (``structures''); simultaneous
  4222 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4223 some examples;
  4224 
  4225 * Pure: the following commands have been ``localized'', supporting a
  4226 target locale specification "(in name)": 'lemma', 'theorem',
  4227 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4228 stored both within the locale and at the theory level (exported and
  4229 qualified by the locale name);
  4230 
  4231 * Pure: theory goals may now be specified in ``long'' form, with
  4232 ad-hoc contexts consisting of arbitrary locale elements. for example
  4233 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4234 definitions may be given, too); the result is a meta-level rule with
  4235 the context elements being discharged in the obvious way;
  4236 
  4237 * Pure: new proof command 'using' allows to augment currently used
  4238 facts after a goal statement ('using' is syntactically analogous to
  4239 'apply', but acts on the goal's facts only); this allows chained facts
  4240 to be separated into parts given before and after a claim, as in
  4241 ``from a and b have C using d and e <proof>'';
  4242 
  4243 * Pure: renamed "antecedent" case to "rule_context";
  4244 
  4245 * Pure: new 'judgment' command records explicit information about the
  4246 object-logic embedding (used by several tools internally); no longer
  4247 use hard-wired "Trueprop";
  4248 
  4249 * Pure: added 'corollary' command;
  4250 
  4251 * Pure: fixed 'token_translation' command;
  4252 
  4253 * Pure: removed obsolete 'exported' attribute;
  4254 
  4255 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4256 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4257 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4258 
  4259 * Pure: method 'atomize' presents local goal premises as object-level
  4260 statements (atomic meta-level propositions); setup controlled via
  4261 rewrite rules declarations of 'atomize' attribute; example
  4262 application: 'induct' method with proper rule statements in improper
  4263 proof *scripts*;
  4264 
  4265 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4266 now consider the syntactic context of assumptions, giving a better
  4267 chance to get type-inference of the arguments right (this is
  4268 especially important for locales);
  4269 
  4270 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4271 mode;
  4272 
  4273 * Pure/obtain: the formal conclusion "thesis", being marked as
  4274 ``internal'', may no longer be reference directly in the text;
  4275 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4276 situations;
  4277 
  4278 * Pure: generic 'sym' attribute which declares a rule both as pure
  4279 'elim?' and for the 'symmetric' operation;
  4280 
  4281 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4282 text; the fixed correlation with particular command syntax has been
  4283 discontinued;
  4284 
  4285 * Pure: new method 'rules' is particularly well-suited for proof
  4286 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4287 but often produces more compact proof terms with less detours;
  4288 
  4289 * Pure/Provers/classical: simplified integration with pure rule
  4290 attributes and methods; the classical "intro?/elim?/dest?"
  4291 declarations coincide with the pure ones; the "rule" method no longer
  4292 includes classically swapped intros; "intro" and "elim" methods no
  4293 longer pick rules from the context; also got rid of ML declarations
  4294 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4295 INCOMPATIBILITY;
  4296 
  4297 * Provers/classical: attribute 'swapped' produces classical inversions
  4298 of introduction rules;
  4299 
  4300 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4301 rules instead of full simplifier context; 'iff' attribute handles
  4302 conditional rules;
  4303 
  4304 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4305 
  4306 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4307 "(permissive)" option to recover old behavior;
  4308 
  4309 * HOL: 'inductive' no longer features separate (collective) attributes
  4310 for 'intros' (was found too confusing);
  4311 
  4312 * HOL: properly declared induction rules less_induct and
  4313 wf_induct_rule;
  4314 
  4315 
  4316 *** HOL ***
  4317 
  4318 * HOL: moved over to sane numeral syntax; the new policy is as
  4319 follows:
  4320 
  4321   - 0 and 1 are polymorphic constants, which are defined on any
  4322   numeric type (nat, int, real etc.);
  4323 
  4324   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4325   binary representation internally;
  4326 
  4327   - type nat has special constructor Suc, and generally prefers Suc 0
  4328   over 1::nat and Suc (Suc 0) over 2::nat;
  4329 
  4330 This change may cause significant problems of INCOMPATIBILITY; here
  4331 are some hints on converting existing sources:
  4332 
  4333   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4334   entities, so expressions involving "-" (unary or binary minus) need
  4335   to be spaced properly;
  4336 
  4337   - existing occurrences of "1" may need to be constraint "1::nat" or
  4338   even replaced by Suc 0; similar for old "2";
  4339 
  4340   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4341 
  4342   - remove all special provisions on numerals in proofs;
  4343 
  4344 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4345 representation (depends on bin_arith_simps in the default context);
  4346 
  4347 * HOL: symbolic syntax for x^2 (numeral 2);
  4348 
  4349 * HOL: the class of all HOL types is now called "type" rather than
  4350 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4351 in axclass/classes, instance/arities, and (usually rare) occurrences
  4352 in typings (of consts etc.); internally the class is called
  4353 "HOL.type", ML programs should refer to HOLogic.typeS;
  4354 
  4355 * HOL/record package improvements:
  4356   - new derived operations "fields" to build a partial record section,
  4357     "extend" to promote a fixed record to a record scheme, and
  4358     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4359     declared as simp by default;
  4360   - shared operations ("more", "fields", etc.) now need to be always
  4361     qualified) --- potential INCOMPATIBILITY;
  4362   - removed "make_scheme" operations (use "make" with "extend") --
  4363     INCOMPATIBILITY;
  4364   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4365   - provides cases/induct rules for use with corresponding Isar
  4366     methods (for concrete records, record schemes, concrete more
  4367     parts, and schematic more parts -- in that order);
  4368   - internal definitions directly based on a light-weight abstract
  4369     theory of product types over typedef rather than datatype;
  4370 
  4371 * HOL: generic code generator for generating executable ML code from
  4372 specifications; specific support for HOL constructs such as inductive
  4373 datatypes and sets, as well as recursive functions; can be invoked
  4374 via 'generate_code' theory section;
  4375 
  4376 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4377 
  4378 * HOL: consolidated and renamed several theories.  In particular:
  4379         Ord.thy has been absorbed into HOL.thy
  4380         String.thy has been absorbed into List.thy
  4381 
  4382 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4383 (beware of argument permutation!);
  4384 
  4385 * HOL: linorder_less_split superseded by linorder_cases;
  4386 
  4387 * HOL/List: "nodups" renamed to "distinct";
  4388 
  4389 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4390 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4391   - Ex_def has changed, now need to use some_eq_ex
  4392 
  4393 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4394 in this (rare) case use:
  4395 
  4396   delSWrapper "split_all_tac"
  4397   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4398 
  4399 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4400 MAY FAIL;
  4401 
  4402 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4403 Isabelle's type classes, ^ on functions and relations has too general
  4404 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4405 necessary to attach explicit type constraints;
  4406 
  4407 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4408 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4409 renamed accordingly (eg "compI" -> "rel_compI").
  4410 
  4411 * HOL: syntax translations now work properly with numerals and records
  4412 expressions;
  4413 
  4414 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4415 of "lam" -- INCOMPATIBILITY;
  4416 
  4417 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4418 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4419 renamed "Product_Type.unit";
  4420 
  4421 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4422 
  4423 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4424 the "cases" method);
  4425 
  4426 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4427 Florian Kammller);
  4428 
  4429 * HOL/IMP: updated and converted to new-style theory format; several
  4430 parts turned into readable document, with proper Isar proof texts and
  4431 some explanations (by Gerwin Klein);
  4432 
  4433 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4434 
  4435 * HOL-Hyperreal is now a logic image;
  4436 
  4437 
  4438 *** HOLCF ***
  4439 
  4440 * Isar: consts/constdefs supports mixfix syntax for continuous
  4441 operations;
  4442 
  4443 * Isar: domain package adapted to new-style theory format, e.g. see
  4444 HOLCF/ex/Dnat.thy;
  4445 
  4446 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4447 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4448 lift.induct_tac, always use UU instead of Undef;
  4449 
  4450 * HOLCF/IMP: updated and converted to new-style theory;
  4451 
  4452 
  4453 *** ZF ***
  4454 
  4455 * Isar: proper integration of logic-specific tools and packages,
  4456 including theory commands '(co)inductive', '(co)datatype',
  4457 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4458 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4459 
  4460 * theory Main no longer includes AC; for the Axiom of Choice, base
  4461 your theory on Main_ZFC;
  4462 
  4463 * the integer library now covers quotients and remainders, with many
  4464 laws relating division to addition, multiplication, etc.;
  4465 
  4466 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4467 typeless version of the formalism;
  4468 
  4469 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4470 format;
  4471 
  4472 * ZF/Induct: new directory for examples of inductive definitions,
  4473 including theory Multiset for multiset orderings; converted to
  4474 new-style theory format;
  4475 
  4476 * ZF: many new theorems about lists, ordinals, etc.;
  4477 
  4478 
  4479 *** General ***
  4480 
  4481 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4482 variable proof controls level of detail: 0 = no proofs (only oracle
  4483 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4484 also ref manual for further ML interfaces;
  4485 
  4486 * Pure/axclass: removed obsolete ML interface
  4487 goal_subclass/goal_arity;
  4488 
  4489 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4490 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4491 separate tokens, so expressions involving minus need to be spaced
  4492 properly;
  4493 
  4494 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4495 rather than "infixl" or "infixr";
  4496 
  4497 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4498 sort constraint specifications in type inference; e.g. "x::_::foo"
  4499 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4500 type variable);
  4501 
  4502 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4503 control output of nested => (types); the default behavior is
  4504 "type_brackets";
  4505 
  4506 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4507 tokens into AST constants;
  4508 
  4509 * Pure/syntax: prefer later declarations of translations and print
  4510 translation functions; potential INCOMPATIBILITY: need to reverse
  4511 multiple declarations for same syntax element constant;
  4512 
  4513 * Pure/show_hyps reset by default (in accordance to existing Isar
  4514 practice);
  4515 
  4516 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4517 addSafter;
  4518 
  4519 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4520 as well;
  4521 
  4522 * system: tested support for MacOS X; should be able to get Isabelle +
  4523 Proof General to work in a plain Terminal after installing Poly/ML
  4524 (e.g. from the Isabelle distribution area) and GNU bash alone
  4525 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4526 support requires further installations, e.g. from
  4527 http://fink.sourceforge.net/);
  4528 
  4529 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4530 
  4531 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4532 of 40 MB), cf. ML_OPTIONS;
  4533 
  4534 * system: Proof General keywords specification is now part of the
  4535 Isabelle distribution (see etc/isar-keywords.el);
  4536 
  4537 * system: support for persistent Proof General sessions (refrain from
  4538 outdating all loaded theories on startup); user may create writable
  4539 logic images like this: ``isabelle -q HOL Test'';
  4540 
  4541 * system: smart selection of Isabelle process versus Isabelle
  4542 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4543 run both "isabelle" and "Isabelle" even if file names are badly
  4544 damaged (executable inspects the case of the first letter of its own
  4545 name); added separate "isabelle-process" and "isabelle-interface";
  4546 
  4547 * system: refrain from any attempt at filtering input streams; no
  4548 longer support ``8bit'' encoding of old isabelle font, instead proper
  4549 iso-latin characters may now be used; the related isatools
  4550 "symbolinput" and "nonascii" have disappeared as well;
  4551 
  4552 * system: removed old "xterm" interface (the print modes "xterm" and
  4553 "xterm_color" are still available for direct use in a suitable
  4554 terminal);
  4555 
  4556 
  4557 
  4558 New in Isabelle99-2 (February 2001)
  4559 -----------------------------------
  4560 
  4561 *** Overview of INCOMPATIBILITIES ***
  4562 
  4563 * HOL: please note that theories in the Library and elsewhere often use the
  4564 new-style (Isar) format; to refer to their theorems in an ML script you must
  4565 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4566 
  4567 * HOL: inductive package no longer splits induction rule aggressively,
  4568 but only as far as specified by the introductions given; the old
  4569 format may be recovered via ML function complete_split_rule or attribute
  4570 'split_rule (complete)';
  4571 
  4572 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4573 gfp_Tarski to gfp_unfold;
  4574 
  4575 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4576 
  4577 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4578 relation); infix "^^" has been renamed "``"; infix "``" has been
  4579 renamed "`"; "univalent" has been renamed "single_valued";
  4580 
  4581 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4582 operation;
  4583 
  4584 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4585 
  4586 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4587 
  4588 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4589 consequence, it is no longer monotonic wrt. the local goal context
  4590 (which is now passed through the inductive cases);
  4591 
  4592 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4593 \<gg> to \<ggreater>;
  4594 
  4595 
  4596 *** Document preparation ***
  4597 
  4598 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4599 available: are "it" for near math-mode best-style output, "sl" for
  4600 slanted text style, and "tt" for plain type-writer; if no
  4601 \isabellestyle command is given, output is according to slanted
  4602 type-writer);
  4603 
  4604 * support sub/super scripts (for single symbols only), input syntax is
  4605 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4606 
  4607 * some more standard symbols; see Appendix A of the system manual for
  4608 the complete list of symbols defined in isabellesym.sty;
  4609 
  4610 * improved isabelle style files; more abstract symbol implementation
  4611 (should now use \isamath{...} and \isatext{...} in custom symbol
  4612 definitions);
  4613 
  4614 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4615 state; Note that presentation of goal states does not conform to
  4616 actual human-readable proof documents.  Please do not include goal
  4617 states into document output unless you really know what you are doing!
  4618 
  4619 * proper indentation of antiquoted output with proportional LaTeX
  4620 fonts;
  4621 
  4622 * no_document ML operator temporarily disables LaTeX document
  4623 generation;
  4624 
  4625 * isatool unsymbolize tunes sources for plain ASCII communication;
  4626 
  4627 
  4628 *** Isar ***
  4629 
  4630 * Pure: Isar now suffers initial goal statements to contain unbound
  4631 schematic variables (this does not conform to actual readable proof
  4632 documents, due to unpredictable outcome and non-compositional proof
  4633 checking); users who know what they are doing may use schematic goals
  4634 for Prolog-style synthesis of proven results;
  4635 
  4636 * Pure: assumption method (an implicit finishing) now handles actual
  4637 rules as well;
  4638 
  4639 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4640 initial goal, declare "that" only as Pure intro (only for single
  4641 steps); the "that" rule assumption may now be involved in implicit
  4642 finishing, thus ".." becomes a feasible for trivial obtains;
  4643 
  4644 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4645 instance proofs may be performed by "..";
  4646 
  4647 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4648 statements as well;
  4649 
  4650 * Pure: more robust selection of calculational rules;
  4651 
  4652 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4653 rule (as well as the assumption rule);
  4654 
  4655 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4656 lemmas, using the graph browser tool;
  4657 
  4658 * Pure: predict failure of "show" in interactive mode;
  4659 
  4660 * Pure: 'thms_containing' now takes actual terms as arguments;
  4661 
  4662 * HOL: improved method 'induct' --- now handles non-atomic goals
  4663 (potential INCOMPATIBILITY); tuned error handling;
  4664 
  4665 * HOL: cases and induct rules now provide explicit hints about the
  4666 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4667 any remaining facts are inserted into the goal verbatim;
  4668 
  4669 * HOL: local contexts (aka cases) may now contain term bindings as
  4670 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4671 the result to be shown in each case;
  4672 
  4673 * HOL: added 'recdef_tc' command;
  4674 
  4675 * isatool convert assists in eliminating legacy ML scripts;
  4676 
  4677 
  4678 *** HOL ***
  4679 
  4680 * HOL/Library: a collection of generic theories to be used together
  4681 with main HOL; the theory loader path already includes this directory
  4682 by default; the following existing theories have been moved here:
  4683 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4684 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4685 
  4686 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4687 modelling and verification task performed in Isabelle/HOL +
  4688 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4689 
  4690 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4691 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4692 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4693 'domain', this makes the theory consistent with mathematical
  4694 literature;
  4695 
  4696 * HOL basics: added overloaded operations "inverse" and "divide"
  4697 (infix "/"), syntax for generic "abs" operation, generic summation
  4698 operator \<Sum>;
  4699 
  4700 * HOL/typedef: simplified package, provide more useful rules (see also
  4701 HOL/subset.thy);
  4702 
  4703 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4704 now expressed as a proper nested rule (old-style tactic scripts may
  4705 require atomize_strip_tac to cope with non-atomic premises);
  4706 
  4707 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4708 to "split_conv" (old name still available for compatibility);
  4709 
  4710 * HOL: improved concrete syntax for strings (e.g. allows translation
  4711 rules with string literals);
  4712 
  4713 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4714  and Fleuriot's mechanization of analysis, including the transcendental
  4715  functions for the reals;
  4716 
  4717 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4718 
  4719 
  4720 *** CTT ***
  4721 
  4722 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4723 "lam" is displayed as TWO lambda-symbols
  4724 
  4725 * CTT: theory Main now available, containing everything (that is, Bool
  4726 and Arith);
  4727 
  4728 
  4729 *** General ***
  4730 
  4731 * Pure: the Simplifier has been implemented properly as a derived rule
  4732 outside of the actual kernel (at last!); the overall performance
  4733 penalty in practical applications is about 50%, while reliability of
  4734 the Isabelle inference kernel has been greatly improved;
  4735 
  4736 * print modes "brackets" and "no_brackets" control output of nested =>
  4737 (types) and ==> (props); the default behaviour is "brackets";
  4738 
  4739 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4740 as assumptions as well;
  4741 
  4742 * system: support Poly/ML 4.0;
  4743 
  4744 * system: isatool install handles KDE version 1 or 2;
  4745 
  4746 
  4747 
  4748 New in Isabelle99-1 (October 2000)
  4749 ----------------------------------
  4750 
  4751 *** Overview of INCOMPATIBILITIES ***
  4752 
  4753 * HOL: simplification of natural numbers is much changed; to partly
  4754 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4755 issue the following ML commands:
  4756 
  4757   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4758   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4759 
  4760 * HOL: simplification no longer dives into case-expressions; this is
  4761 controlled by "t.weak_case_cong" for each datatype t;
  4762 
  4763 * HOL: nat_less_induct renamed to less_induct;
  4764 
  4765 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4766 fixsome to patch .thy and .ML sources automatically;
  4767 
  4768   select_equality  -> some_equality
  4769   select_eq_Ex     -> some_eq_ex
  4770   selectI2EX       -> someI2_ex
  4771   selectI2         -> someI2
  4772   selectI          -> someI
  4773   select1_equality -> some1_equality
  4774   Eps_sym_eq       -> some_sym_eq_trivial
  4775   Eps_eq           -> some_eq_trivial
  4776 
  4777 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4778 
  4779 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4780 instead);
  4781 
  4782 * HOL: the recursion equations generated by 'recdef' are now called
  4783 f.simps instead of f.rules;
  4784 
  4785 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4786 
  4787 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4788 sometimes be needed;
  4789 
  4790 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4791 
  4792 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4793 
  4794 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4795 product is now "<*>" instead of "Times"; the lexicographic product is
  4796 now "<*lex*>" instead of "**";
  4797 
  4798 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4799 of main HOL, but was unused); better use HOL's datatype package;
  4800 
  4801 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4802 the old syntax may be recovered as follows:
  4803 
  4804   syntax (symbols)
  4805     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4806       (infixl "\\<oplus>" 100)
  4807 
  4808 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4809 
  4810 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4811 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4812 internally;
  4813 
  4814 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4815 changed from A/r to A//r;
  4816 
  4817 * ZF: new treatment of arithmetic (nat & int) may break some old
  4818 proofs;
  4819 
  4820 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4821 rulify -> rule_format, elimify -> elim_format, ...);
  4822 
  4823 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4824 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4825 should have to change intro!! to intro? only); replaced "delrule" by
  4826 "rule del";
  4827 
  4828 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4829 
  4830 * Provers: strengthened force_tac by using new first_best_tac;
  4831 
  4832 * LaTeX document preparation: several changes of isabelle.sty (see
  4833 lib/texinputs);
  4834 
  4835 
  4836 *** Document preparation ***
  4837 
  4838 * formal comments (text blocks etc.) in new-style theories may now
  4839 contain antiquotations of thm/prop/term/typ/text to be presented
  4840 according to latex print mode; concrete syntax is like this:
  4841 @{term[show_types] "f(x) = a + x"};
  4842 
  4843 * isatool mkdir provides easy setup of Isabelle session directories,
  4844 including proper document sources;
  4845 
  4846 * generated LaTeX sources are now deleted after successful run
  4847 (isatool document -c); may retain a copy somewhere else via -D option
  4848 of isatool usedir;
  4849 
  4850 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4851 style files, achieving self-contained LaTeX sources and simplifying
  4852 LaTeX debugging;
  4853 
  4854 * old-style theories now produce (crude) LaTeX output as well;
  4855 
  4856 * browser info session directories are now self-contained (may be put
  4857 on WWW server seperately); improved graphs of nested sessions; removed
  4858 graph for 'all sessions';
  4859 
  4860 * several improvements in isabelle style files; \isabellestyle{it}
  4861 produces fake math mode output; \isamarkupheader is now \section by
  4862 default; see lib/texinputs/isabelle.sty etc.;
  4863 
  4864 
  4865 *** Isar ***
  4866 
  4867 * Isar/Pure: local results and corresponding term bindings are now
  4868 subject to Hindley-Milner polymorphism (similar to ML); this
  4869 accommodates incremental type-inference very nicely;
  4870 
  4871 * Isar/Pure: new derived language element 'obtain' supports
  4872 generalized existence reasoning;
  4873 
  4874 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4875 support accumulation of results, without applying any rules yet;
  4876 useful to collect intermediate results without explicit name
  4877 references, and for use with transitivity rules with more than 2
  4878 premises;
  4879 
  4880 * Isar/Pure: scalable support for case-analysis type proofs: new
  4881 'case' language element refers to local contexts symbolically, as
  4882 produced by certain proof methods; internally, case names are attached
  4883 to theorems as "tags";
  4884 
  4885 * Isar/Pure: theory command 'hide' removes declarations from
  4886 class/type/const name spaces;
  4887 
  4888 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4889 indicate potential overloading;
  4890 
  4891 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4892 
  4893 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4894 "{a,b,c}" instead of {a,b,c};
  4895 
  4896 * Isar/Pure now provides its own version of intro/elim/dest
  4897 attributes; useful for building new logics, but beware of confusion
  4898 with the version in Provers/classical;
  4899 
  4900 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4901 case name 'antecedent';
  4902 
  4903 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4904 to the current context is now done automatically);
  4905 
  4906 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4907 for definining proof methods in ML;
  4908 
  4909 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4910 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4911 most cases, one should have to change intro!! to intro? only);
  4912 replaced "delrule" by "rule del";
  4913 
  4914 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4915 'symmetric' attribute (the latter supercedes [RS sym]);
  4916 
  4917 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4918 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4919 well (including splits);
  4920 
  4921 * Isar/Provers: Simplifier and Classical methods now support all kind
  4922 of modifiers used in the past, including 'cong', 'iff', etc.
  4923 
  4924 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4925 of Simplifier and Classical reasoner);
  4926 
  4927 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4928 now support named cases; major packages (inductive, datatype, primrec,
  4929 recdef) support case names and properly name parameters;
  4930 
  4931 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4932 monotonicity conditions are extracted to be proven at end of
  4933 calculations;
  4934 
  4935 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4936 method anyway;
  4937 
  4938 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4939 split_if split_if_asm; datatype package provides theorems foo.splits =
  4940 foo.split foo.split_asm for each datatype;
  4941 
  4942 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4943 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4944 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4945 use "(cases (simplified))" method in proper proof texts);
  4946 
  4947 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4948 
  4949 * Isar: names of theorems etc. may be natural numbers as well;
  4950 
  4951 * Isar: 'pr' command: optional arguments for goals_limit and
  4952 ProofContext.prems_limit; no longer prints theory contexts, but only
  4953 proof states;
  4954 
  4955 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4956 additional print modes to be specified; e.g. "pr(latex)" will print
  4957 proof state according to the Isabelle LaTeX style;
  4958 
  4959 * Isar: improved support for emulating tactic scripts, including proof
  4960 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4961 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4962 (for HOL datatypes);
  4963 
  4964 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4965 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4966 'proof method scripts' have to be in depth-first order;
  4967 
  4968 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4969 
  4970 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4971 should instead use individual commands for printing items
  4972 (print_commands, print_methods etc.);
  4973 
  4974 * Isar: added 'nothing' --- the empty list of theorems;
  4975 
  4976 
  4977 *** HOL ***
  4978 
  4979 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4980 corresponding virtual machine and a specification of its bytecode
  4981 verifier and a lightweight bytecode verifier, including proofs of
  4982 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4983 Cornelia Pusch (see also the homepage of project Bali at
  4984 http://isabelle.in.tum.de/Bali/);
  4985 
  4986 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4987 Clemens Ballarin;
  4988 
  4989 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4990 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4991 Rasmussen;
  4992 
  4993 * HOL/Lattice: fundamental concepts of lattice theory and order
  4994 structures, including duals, properties of bounds versus algebraic
  4995 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4996 Theorem for complete lattices etc.; may also serve as a demonstration
  4997 for abstract algebraic reasoning using axiomatic type classes, and
  4998 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4999 
  5000 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  5001 von Oheimb;
  5002 
  5003 * HOL/IMPP: extension of IMP with local variables and mutually
  5004 recursive procedures, by David von Oheimb;
  5005 
  5006 * HOL/Lambda: converted into new-style theory and document;
  5007 
  5008 * HOL/ex/Multiquote: example of multiple nested quotations and
  5009 anti-quotations -- basically a generalized version of de-Bruijn
  5010 representation; very useful in avoiding lifting of operations;
  5011 
  5012 * HOL/record: added general record equality rule to simpset; fixed
  5013 select-update simplification procedure to handle extended records as
  5014 well; admit "r" as field name;
  5015 
  5016 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  5017 other numeric types and also as the identity of groups, rings, etc.;
  5018 
  5019 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  5020 Types nat and int belong to this axclass;
  5021 
  5022 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  5023    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  5024    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  5025   two terms #m*u and #n*u are replaced by #(m+n)*u
  5026     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  5027   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  5028     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  5029 
  5030 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  5031 powerful prover for predicate logic but knows nothing of clasets; see
  5032 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  5033 
  5034 * HOL: new version of "case_tac" subsumes both boolean case split and
  5035 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  5036 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  5037 
  5038 * HOL: simplification no longer dives into case-expressions: only the
  5039 selector expression is simplified, but not the remaining arms; to
  5040 enable full simplification of case-expressions for datatype t, you may
  5041 remove t.weak_case_cong from the simpset, either globally (Delcongs
  5042 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  5043 
  5044 * HOL/recdef: the recursion equations generated by 'recdef' for
  5045 function 'f' are now called f.simps instead of f.rules; if all
  5046 termination conditions are proved automatically, these simplification
  5047 rules are added to the simpset, as in primrec; rules may be named
  5048 individually as well, resulting in a separate list of theorems for
  5049 each equation;
  5050 
  5051 * HOL/While is a new theory that provides a while-combinator. It
  5052 permits the definition of tail-recursive functions without the
  5053 provision of a termination measure. The latter is necessary once the
  5054 invariant proof rule for while is applied.
  5055 
  5056 * HOL: new (overloaded) notation for the set of elements below/above
  5057 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5058 
  5059 * HOL: theorems impI, allI, ballI bound as "strip";
  5060 
  5061 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5062 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5063 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5064 
  5065 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5066 
  5067 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5068 main HOL, but was unused);
  5069 
  5070 * HOL: fewer consts declared as global (e.g. have to refer to
  5071 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5072 
  5073 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5074 in case of overlap with user translations (e.g. judgements over
  5075 tuples); (note that the underlying logical represenation is still
  5076 bogus);
  5077 
  5078 
  5079 *** ZF ***
  5080 
  5081 * ZF: simplification automatically cancels common terms in arithmetic
  5082 expressions over nat and int;
  5083 
  5084 * ZF: new treatment of nat to minimize type-checking: all operators
  5085 coerce their operands to a natural number using the function natify,
  5086 making the algebraic laws unconditional;
  5087 
  5088 * ZF: as above, for int: operators coerce their operands to an integer
  5089 using the function intify;
  5090 
  5091 * ZF: the integer library now contains many of the usual laws for the
  5092 orderings, including $<=, and monotonicity laws for $+ and $*;
  5093 
  5094 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5095 simplification;
  5096 
  5097 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5098 to the simplifier and classical reasoner simultaneously;
  5099 
  5100 
  5101 *** General ***
  5102 
  5103 * Provers: blast_tac now handles actual object-logic rules as
  5104 assumptions; note that auto_tac uses blast_tac internally as well;
  5105 
  5106 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5107 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5108 
  5109 * Provers: delrules now handles destruct rules as well (no longer need
  5110 explicit make_elim);
  5111 
  5112 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5113   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5114 use instead the strong form,
  5115   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5116 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5117 from destruct-rules;
  5118 
  5119 * Provers: Simplifier.easy_setup provides a fast path to basic
  5120 Simplifier setup for new object-logics;
  5121 
  5122 * Pure: AST translation rules no longer require constant head on LHS;
  5123 
  5124 * Pure: improved name spaces: ambiguous output is qualified; support
  5125 for hiding of names;
  5126 
  5127 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5128 XSYMBOL_HOME; no longer need to do manual configuration in most
  5129 situations;
  5130 
  5131 * system: compression of ML heaps images may now be controlled via -c
  5132 option of isabelle and isatool usedir (currently only observed by
  5133 Poly/ML);
  5134 
  5135 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5136 useful for remote X11);
  5137 
  5138 * system: provide TAGS file for Isabelle sources;
  5139 
  5140 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5141 order;
  5142 
  5143 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5144 timing flag supersedes proof_timing and Toplevel.trace;
  5145 
  5146 * ML: new combinators |>> and |>>> for incremental transformations
  5147 with secondary results (e.g. certain theory extensions):
  5148 
  5149 * ML: PureThy.add_defs gets additional argument to indicate potential
  5150 overloading (usually false);
  5151 
  5152 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5153 results;
  5154 
  5155 
  5156 
  5157 New in Isabelle99 (October 1999)
  5158 --------------------------------
  5159 
  5160 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5161 
  5162 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5163 are no longer simplified.  (This allows the simplifier to unfold recursive
  5164 functional programs.)  To restore the old behaviour, declare
  5165 
  5166     Delcongs [if_weak_cong];
  5167 
  5168 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5169 complement;
  5170 
  5171 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5172 
  5173 * HOL/datatype: mutual_induct_tac no longer exists --
  5174   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5175 
  5176 * HOL/typedef: fixed type inference for representing set; type
  5177 arguments now have to occur explicitly on the rhs as type constraints;
  5178 
  5179 * ZF: The con_defs part of an inductive definition may no longer refer
  5180 to constants declared in the same theory;
  5181 
  5182 * HOL, ZF: the function mk_cases, generated by the inductive
  5183 definition package, has lost an argument.  To simplify its result, it
  5184 uses the default simpset instead of a supplied list of theorems.
  5185 
  5186 * HOL/List: the constructors of type list are now Nil and Cons;
  5187 
  5188 * Simplifier: the type of the infix ML functions
  5189         setSSolver addSSolver setSolver addSolver
  5190 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5191 for packaging solvers. A solver is created via
  5192         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5193 where the string argument is only a comment.
  5194 
  5195 
  5196 *** Proof tools ***
  5197 
  5198 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5199 decision procedure for linear arithmetic. Currently it is used for
  5200 types `nat', `int', and `real' in HOL (see below); it can, should and
  5201 will be instantiated for other types and logics as well.
  5202 
  5203 * The simplifier now accepts rewrite rules with flexible heads, eg
  5204      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5205   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5206   matching.
  5207 
  5208 
  5209 *** General ***
  5210 
  5211 * New Isabelle/Isar subsystem provides an alternative to traditional
  5212 tactical theorem proving; together with the ProofGeneral/isar user
  5213 interface it offers an interactive environment for developing human
  5214 readable proof documents (Isar == Intelligible semi-automated
  5215 reasoning); for further information see isatool doc isar-ref,
  5216 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5217 
  5218 * improved and simplified presentation of theories: better HTML markup
  5219 (including colors), graph views in several sizes; isatool usedir now
  5220 provides a proper interface for user theories (via -P option); actual
  5221 document preparation based on (PDF)LaTeX is available as well (for
  5222 new-style theories only); see isatool doc system for more information;
  5223 
  5224 * native support for Proof General, both for classic Isabelle and
  5225 Isabelle/Isar;
  5226 
  5227 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5228 using the graph browser tool;
  5229 
  5230 * Isabelle manuals now also available as PDF;
  5231 
  5232 * theory loader rewritten from scratch (may not be fully
  5233 bug-compatible); old loadpath variable has been replaced by show_path,
  5234 add_path, del_path, reset_path functions; new operations such as
  5235 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5236 isatool doc ref);
  5237 
  5238 * improved isatool install: option -k creates KDE application icon,
  5239 option -p DIR installs standalone binaries;
  5240 
  5241 * added ML_PLATFORM setting (useful for cross-platform installations);
  5242 more robust handling of platform specific ML images for SML/NJ;
  5243 
  5244 * the settings environment is now statically scoped, i.e. it is never
  5245 created again in sub-processes invoked from isabelle, isatool, or
  5246 Isabelle;
  5247 
  5248 * path element specification '~~' refers to '$ISABELLE_HOME';
  5249 
  5250 * in locales, the "assumes" and "defines" parts may be omitted if
  5251 empty;
  5252 
  5253 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5254 long arrows);
  5255 
  5256 * new print_mode "HTML";
  5257 
  5258 * new flag show_tags controls display of tags of theorems (which are
  5259 basically just comments that may be attached by some tools);
  5260 
  5261 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5262 mode and goal output format:
  5263 
  5264 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5265 244c244
  5266 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5267 ---
  5268 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5269 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5270 181c181
  5271 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5272 ---
  5273 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5274 
  5275 * function bind_thms stores lists of theorems (cf. bind_thm);
  5276 
  5277 * new shorthand tactics ftac, eatac, datac, fatac;
  5278 
  5279 * qed (and friends) now accept "" as result name; in that case the
  5280 theorem is not stored, but proper checks and presentation of the
  5281 result still apply;
  5282 
  5283 * theorem database now also indexes constants "Trueprop", "all",
  5284 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5285 
  5286 
  5287 *** HOL ***
  5288 
  5289 ** HOL arithmetic **
  5290 
  5291 * There are now decision procedures for linear arithmetic over nat and
  5292 int:
  5293 
  5294 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5295 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5296 are treated as atomic; subformulae not involving type `nat' or `int'
  5297 are ignored; quantified subformulae are ignored unless they are
  5298 positive universal or negative existential. The tactic has to be
  5299 invoked by hand and can be a little bit slow. In particular, the
  5300 running time is exponential in the number of occurrences of `min' and
  5301 `max', and `-' on `nat'.
  5302 
  5303 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5304 (negated) (in)equalities among the premises and the conclusion into
  5305 account (i.e. no compound formulae) and does not know about `min' and
  5306 `max', and `-' on `nat'. It is fast and is used automatically by the
  5307 simplifier.
  5308 
  5309 NB: At the moment, these decision procedures do not cope with mixed
  5310 nat/int formulae where the two parts interact, such as `m < n ==>
  5311 int(m) < int(n)'.
  5312 
  5313 * HOL/Numeral provides a generic theory of numerals (encoded
  5314 efficiently as bit strings); setup for types nat/int/real is in place;
  5315 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5316 int, existing theories and proof scripts may require a few additional
  5317 type constraints;
  5318 
  5319 * integer division and remainder can now be performed on constant
  5320 arguments;
  5321 
  5322 * many properties of integer multiplication, division and remainder
  5323 are now available;
  5324 
  5325 * An interface to the Stanford Validity Checker (SVC) is available through the
  5326 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5327 are proved automatically.  SVC must be installed separately, and its results
  5328 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5329 invocation of the underlying oracle).  For SVC see
  5330   http://verify.stanford.edu/SVC
  5331 
  5332 * IsaMakefile: the HOL-Real target now builds an actual image;
  5333 
  5334 
  5335 ** HOL misc **
  5336 
  5337 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5338 (in Isabelle/Isar) -- by Gertrud Bauer;
  5339 
  5340 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5341 analysis for assembly languages with subtypes;
  5342 
  5343 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5344 -- avoids syntactic ambiguities and treats state, transition, and
  5345 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5346 changed syntax and (many) tactics;
  5347 
  5348 * HOL/inductive: Now also handles more general introduction rules such
  5349   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5350   theorems are now maintained within the theory (maintained via the
  5351   "mono" attribute);
  5352 
  5353 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5354   (using function types) such as
  5355 
  5356   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5357 
  5358 * HOL/record: record_simproc (part of the default simpset) takes care
  5359 of selectors applied to updated records; record_split_tac is no longer
  5360 part of the default claset; update_defs may now be removed from the
  5361 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5362 
  5363   claset_ref () := claset() addSWrapper record_split_wrapper;
  5364   Delsimprocs [record_simproc]
  5365 
  5366 * HOL/typedef: fixed type inference for representing set; type
  5367 arguments now have to occur explicitly on the rhs as type constraints;
  5368 
  5369 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5370 names rather than an ML expression;
  5371 
  5372 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5373 supplied later.  Program schemes can be defined, such as
  5374     "While B C s = (if B s then While B C (C s) else s)"
  5375 where the well-founded relation can be chosen after B and C have been given.
  5376 
  5377 * HOL/List: the constructors of type list are now Nil and Cons;
  5378 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5379 course, ML tools referring to List.list.op # etc. have to be adapted;
  5380 
  5381 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5382 disabled by default; run isabelle with option -m HOL to get back to
  5383 the original Gordon/HOL-style output;
  5384 
  5385 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5386 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5387 
  5388 * HOL basic syntax simplified (more orthogonal): all variants of
  5389 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5390 Eps operator is provided as well: "SOME x. P[x]";
  5391 
  5392 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5393 
  5394 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5395 thus available for user theories;
  5396 
  5397 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5398 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5399 time;
  5400 
  5401 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5402 several times and then mp;
  5403 
  5404 
  5405 *** LK ***
  5406 
  5407 * the notation <<...>> is now available as a notation for sequences of
  5408 formulas;
  5409 
  5410 * the simplifier is now installed
  5411 
  5412 * the axiom system has been generalized (thanks to Soren Heilmann)
  5413 
  5414 * the classical reasoner now has a default rule database
  5415 
  5416 
  5417 *** ZF ***
  5418 
  5419 * new primrec section allows primitive recursive functions to be given
  5420 directly (as in HOL) over datatypes and the natural numbers;
  5421 
  5422 * new tactics induct_tac and exhaust_tac for induction (or case
  5423 analysis) over datatypes and the natural numbers;
  5424 
  5425 * the datatype declaration of type T now defines the recursor T_rec;
  5426 
  5427 * simplification automatically does freeness reasoning for datatype
  5428 constructors;
  5429 
  5430 * automatic type-inference, with AddTCs command to insert new
  5431 type-checking rules;
  5432 
  5433 * datatype introduction rules are now added as Safe Introduction rules
  5434 to the claset;
  5435 
  5436 * the syntax "if P then x else y" is now available in addition to
  5437 if(P,x,y);
  5438 
  5439 
  5440 *** Internal programming interfaces ***
  5441 
  5442 * tuned simplifier trace output; new flag debug_simp;
  5443 
  5444 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5445 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5446 
  5447 * AxClass.axclass_tac lost the theory argument;
  5448 
  5449 * tuned current_goals_markers semantics: begin / end goal avoids
  5450 printing empty lines;
  5451 
  5452 * removed prs and prs_fn hook, which was broken because it did not
  5453 include \n in its semantics, forcing writeln to add one
  5454 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5455 string -> unit if you really want to output text without newline;
  5456 
  5457 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5458 plain output, interface builders may have to enable 'isabelle_font'
  5459 mode to get Isabelle font glyphs as before;
  5460 
  5461 * refined token_translation interface; INCOMPATIBILITY: output length
  5462 now of type real instead of int;
  5463 
  5464 * theory loader actions may be traced via new ThyInfo.add_hook
  5465 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5466 your own database of information attached to *whole* theories -- as
  5467 opposed to intra-theory data slots offered via TheoryDataFun;
  5468 
  5469 * proper handling of dangling sort hypotheses (at last!);
  5470 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5471 extra sort hypotheses that can be witnessed from the type signature;
  5472 the force_strip_shyps flag is gone, any remaining shyps are simply
  5473 left in the theorem (with a warning issued by strip_shyps_warning);
  5474 
  5475 
  5476 
  5477 New in Isabelle98-1 (October 1998)
  5478 ----------------------------------
  5479 
  5480 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5481 
  5482 * several changes of automated proof tools;
  5483 
  5484 * HOL: major changes to the inductive and datatype packages, including
  5485 some minor incompatibilities of theory syntax;
  5486 
  5487 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5488 called `inj_on';
  5489 
  5490 * HOL: removed duplicate thms in Arith:
  5491   less_imp_add_less  should be replaced by  trans_less_add1
  5492   le_imp_add_le      should be replaced by  trans_le_add1
  5493 
  5494 * HOL: unary minus is now overloaded (new type constraints may be
  5495 required);
  5496 
  5497 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5498 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5499 now taken as an integer constant.
  5500 
  5501 * Pure: ML function 'theory_of' renamed to 'theory';
  5502 
  5503 
  5504 *** Proof tools ***
  5505 
  5506 * Simplifier:
  5507   1. Asm_full_simp_tac is now more aggressive.
  5508      1. It will sometimes reorient premises if that increases their power to
  5509         simplify.
  5510      2. It does no longer proceed strictly from left to right but may also
  5511         rotate premises to achieve further simplification.
  5512      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5513      old Asm_full_simp_tac in that it does not rotate premises.
  5514   2. The simplifier now knows a little bit about nat-arithmetic.
  5515 
  5516 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5517 allows for selected deletion of wrappers, by introduction of names for
  5518 wrapper functionals.  This implies that addbefore, addSbefore,
  5519 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5520 and that adding two tactics with the same name overwrites the first
  5521 one (emitting a warning).
  5522   type wrapper = (int -> tactic) -> (int -> tactic)
  5523   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5524   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5525   delWrapper, delSWrapper: claset *  string            -> claset
  5526   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5527 
  5528 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5529 semantics; addbefore now affects only the unsafe part of step_tac
  5530 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5531 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5532 by Force_tac;
  5533 
  5534 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5535 compWrapper; added safe wrapper (and access functions for it);
  5536 
  5537 * HOL/split_all_tac is now much faster and fails if there is nothing
  5538 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5539 and the names of the automatically generated variables have changed.
  5540 split_all_tac has moved within claset() from unsafe wrappers to safe
  5541 wrappers, which means that !!-bound variables are split much more
  5542 aggressively, and safe_tac and clarify_tac now split such variables.
  5543 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5544 Note: the same holds for record_split_tac, which does the job of
  5545 split_all_tac for record fields.
  5546 
  5547 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5548 permanently to the default simpset using Addsplits just like
  5549 Addsimps. They can be removed via Delsplits just like
  5550 Delsimps. Lower-case versions are also available.
  5551 
  5552 * HOL/Simplifier: The rule split_if is now part of the default
  5553 simpset. This means that the simplifier will eliminate all occurrences
  5554 of if-then-else in the conclusion of a goal. To prevent this, you can
  5555 either remove split_if completely from the default simpset by
  5556 `Delsplits [split_if]' or remove it in a specific call of the
  5557 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5558 other case splitting rules to/from the default simpset: every datatype
  5559 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5560 t is the name of the datatype).
  5561 
  5562 * Classical reasoner / Simplifier combination: new force_tac (and
  5563 derivatives Force_tac, force) combines rewriting and classical
  5564 reasoning (and whatever other tools) similarly to auto_tac, but is
  5565 aimed to solve the given subgoal completely.
  5566 
  5567 
  5568 *** General ***
  5569 
  5570 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5571 and `goalw': the theory is no longer needed as an explicit argument -
  5572 the current theory context is used; assumptions are no longer returned
  5573 at the ML-level unless one of them starts with ==> or !!; it is
  5574 recommended to convert to these new commands using isatool fixgoal
  5575 (backup your sources first!);
  5576 
  5577 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5578 the current theory context, and 'theory' to lookup stored theories;
  5579 
  5580 * new theory section 'locale' for declaring constants, assumptions and
  5581 definitions that have local scope;
  5582 
  5583 * new theory section 'nonterminals' for purely syntactic types;
  5584 
  5585 * new theory section 'setup' for generic ML setup functions
  5586 (e.g. package initialization);
  5587 
  5588 * the distribution now includes Isabelle icons: see
  5589 lib/logo/isabelle-{small,tiny}.xpm;
  5590 
  5591 * isatool install - install binaries with absolute references to
  5592 ISABELLE_HOME/bin;
  5593 
  5594 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5595 
  5596 * print mode 'emacs' reserved for Isamode;
  5597 
  5598 * support multiple print (ast) translations per constant name;
  5599 
  5600 * theorems involving oracles are now printed with a suffixed [!];
  5601 
  5602 
  5603 *** HOL ***
  5604 
  5605 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5606 
  5607 * HOL/inductive package reorganized and improved: now supports mutual
  5608 definitions such as
  5609 
  5610   inductive EVEN ODD
  5611     intrs
  5612       null "0 : EVEN"
  5613       oddI "n : EVEN ==> Suc n : ODD"
  5614       evenI "n : ODD ==> Suc n : EVEN"
  5615 
  5616 new theorem list "elims" contains an elimination rule for each of the
  5617 recursive sets; inductive definitions now handle disjunctive premises
  5618 correctly (also ZF);
  5619 
  5620 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5621 "mutual_induct" no longer exists - the induction rule is always
  5622 contained in "induct";
  5623 
  5624 
  5625 * HOL/datatype package re-implemented and greatly improved: now
  5626 supports mutually recursive datatypes such as
  5627 
  5628   datatype
  5629     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5630             | SUM ('a aexp) ('a aexp)
  5631             | DIFF ('a aexp) ('a aexp)
  5632             | NUM 'a
  5633   and
  5634     'a bexp = LESS ('a aexp) ('a aexp)
  5635             | AND ('a bexp) ('a bexp)
  5636             | OR ('a bexp) ('a bexp)
  5637 
  5638 as well as indirectly recursive datatypes such as
  5639 
  5640   datatype
  5641     ('a, 'b) term = Var 'a
  5642                   | App 'b ((('a, 'b) term) list)
  5643 
  5644 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5645 induction on mutually / indirectly recursive datatypes.
  5646 
  5647 Primrec equations are now stored in theory and can be accessed via
  5648 <function_name>.simps.
  5649 
  5650 INCOMPATIBILITIES:
  5651 
  5652   - Theories using datatypes must now have theory Datatype as an
  5653     ancestor.
  5654   - The specific <typename>.induct_tac no longer exists - use the
  5655     generic induct_tac instead.
  5656   - natE has been renamed to nat.exhaust - use exhaust_tac
  5657     instead of res_inst_tac ... natE. Note that the variable
  5658     names in nat.exhaust differ from the names in natE, this
  5659     may cause some "fragile" proofs to fail.
  5660   - The theorems split_<typename>_case and split_<typename>_case_asm
  5661     have been renamed to <typename>.split and <typename>.split_asm.
  5662   - Since default sorts of type variables are now handled correctly,
  5663     some datatype definitions may have to be annotated with explicit
  5664     sort constraints.
  5665   - Primrec definitions no longer require function name and type
  5666     of recursive argument.
  5667 
  5668 Consider using isatool fixdatatype to adapt your theories and proof
  5669 scripts to the new package (backup your sources first!).
  5670 
  5671 
  5672 * HOL/record package: considerably improved implementation; now
  5673 includes concrete syntax for record types, terms, updates; theorems
  5674 for surjective pairing and splitting !!-bound record variables; proof
  5675 support is as follows:
  5676 
  5677   1) standard conversions (selectors or updates applied to record
  5678 constructor terms) are part of the standard simpset;
  5679 
  5680   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5681 made part of standard simpset and claset via addIffs;
  5682 
  5683   3) a tactic for record field splitting (record_split_tac) is part of
  5684 the standard claset (addSWrapper);
  5685 
  5686 To get a better idea about these rules you may retrieve them via
  5687 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5688 the name of your record type.
  5689 
  5690 The split tactic 3) conceptually simplifies by the following rule:
  5691 
  5692   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5693 
  5694 Thus any record variable that is bound by meta-all will automatically
  5695 blow up into some record constructor term, consequently the
  5696 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5697 solve record problems automatically.
  5698 
  5699 
  5700 * reorganized the main HOL image: HOL/Integ and String loaded by
  5701 default; theory Main includes everything;
  5702 
  5703 * automatic simplification of integer sums and comparisons, using cancellation;
  5704 
  5705 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5706 
  5707 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5708 
  5709 * many new identities for unions, intersections, set difference, etc.;
  5710 
  5711 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5712 called split_if, split_split, split_sum_case and split_nat_case (to go
  5713 with add/delsplits);
  5714 
  5715 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5716 (?x::unit) = (); this is made part of the default simpset, which COULD
  5717 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5718 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5719 unit_abs_eta_conv is added in order to counter the effect of
  5720 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5721 %u.f();
  5722 
  5723 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5724 makes more sense);
  5725 
  5726 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5727   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5728   disjointness reasoning but breaking a few old proofs.
  5729 
  5730 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5731 to 'converse' from 'inverse' (for compatibility with ZF and some
  5732 literature);
  5733 
  5734 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5735 the well-founded relation;
  5736 
  5737 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5738     Compl A.  The "Compl" syntax remains available as input syntax for this
  5739     release ONLY.
  5740 
  5741 * HOL/Update: new theory of function updates:
  5742     f(a:=b) == %x. if x=a then b else f x
  5743 may also be iterated as in f(a:=b,c:=d,...);
  5744 
  5745 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5746 
  5747 * HOL/List:
  5748   - new function list_update written xs[i:=v] that updates the i-th
  5749     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5750   - new function `upt' written [i..j(] which generates the list
  5751     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5752     bound write [i..j], which is a shorthand for [i..j+1(].
  5753   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5754 
  5755 * HOL/Arith:
  5756   - removed 'pred' (predecessor) function;
  5757   - generalized some theorems about n-1;
  5758   - many new laws about "div" and "mod";
  5759   - new laws about greatest common divisors (see theory ex/Primes);
  5760 
  5761 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5762 instead of "inverse";
  5763 
  5764 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5765   of the multiset ordering;
  5766 
  5767 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5768   (not included by default);
  5769 
  5770 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5771 
  5772 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5773   programs, i.e. different program variables may have different types.
  5774 
  5775 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5776   [previously, this check worked only if the rewrite rule was unconditional]
  5777   Now rew can involve either definitions or equalities (either == or =).
  5778 
  5779 
  5780 *** ZF ***
  5781 
  5782 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5783   only the theorems proved on ZF.ML;
  5784 
  5785 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5786   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5787   disjointness reasoning but breaking a few old proofs.
  5788 
  5789 * ZF/Update: new theory of function updates
  5790     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5791   may also be iterated as in f(a:=b,c:=d,...);
  5792 
  5793 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5794 
  5795 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5796   [previously, this check worked only if the rewrite rule was unconditional]
  5797   Now rew can involve either definitions or equalities (either == or =).
  5798 
  5799 * case_tac provided for compatibility with HOL
  5800     (like the old excluded_middle_tac, but with subgoals swapped)
  5801 
  5802 
  5803 *** Internal programming interfaces ***
  5804 
  5805 * Pure: several new basic modules made available for general use, see
  5806 also src/Pure/README;
  5807 
  5808 * improved the theory data mechanism to support encapsulation (data
  5809 kind name replaced by private Object.kind, acting as authorization
  5810 key); new type-safe user interface via functor TheoryDataFun; generic
  5811 print_data function becomes basically useless;
  5812 
  5813 * removed global_names compatibility flag -- all theory declarations
  5814 are qualified by default;
  5815 
  5816 * module Pure/Syntax now offers quote / antiquote translation
  5817 functions (useful for Hoare logic etc. with implicit dependencies);
  5818 see HOL/ex/Antiquote for an example use;
  5819 
  5820 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5821 cterm -> thm;
  5822 
  5823 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5824 subgoal;
  5825 
  5826 * Display.print_goals function moved to Locale.print_goals;
  5827 
  5828 * standard print function for goals supports current_goals_markers
  5829 variable for marking begin of proof, end of proof, start of goal; the
  5830 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5831 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5832 for example;
  5833 
  5834 
  5835 
  5836 New in Isabelle98 (January 1998)
  5837 --------------------------------
  5838 
  5839 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5840 
  5841 * changed lexical syntax of terms / types: dots made part of long
  5842 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5843 
  5844 * simpset (and claset) reference variable replaced by functions
  5845 simpset / simpset_ref;
  5846 
  5847 * no longer supports theory aliases (via merge) and non-trivial
  5848 implicit merge of thms' signatures;
  5849 
  5850 * most internal names of constants changed due to qualified names;
  5851 
  5852 * changed Pure/Sequence interface (see Pure/seq.ML);
  5853 
  5854 
  5855 *** General Changes ***
  5856 
  5857 * hierachically structured name spaces (for consts, types, axms, thms
  5858 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5859 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5860 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5861 long_names for fully qualified output names; NOTE: ML programs
  5862 (special tactics, packages etc.) referring to internal names may have
  5863 to be adapted to cope with fully qualified names; in case of severe
  5864 backward campatibility problems try setting 'global_names' at compile
  5865 time to have enrything declared within a flat name space; one may also
  5866 fine tune name declarations in theories via the 'global' and 'local'
  5867 section;
  5868 
  5869 * reimplemented the implicit simpset and claset using the new anytype
  5870 data filed in signatures; references simpset:simpset ref etc. are
  5871 replaced by functions simpset:unit->simpset and
  5872 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5873 to patch your ML files accordingly;
  5874 
  5875 * HTML output now includes theory graph data for display with Java
  5876 applet or isatool browser; data generated automatically via isatool
  5877 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5878 
  5879 * defs may now be conditional; improved rewrite_goals_tac to handle
  5880 conditional equations;
  5881 
  5882 * defs now admits additional type arguments, using TYPE('a) syntax;
  5883 
  5884 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5885 creates a new theory node; implicit merge of thms' signatures is
  5886 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5887 transfer:theory->thm->thm in (rare) cases;
  5888 
  5889 * improved handling of draft signatures / theories; draft thms (and
  5890 ctyps, cterms) are automatically promoted to real ones;
  5891 
  5892 * slightly changed interfaces for oracles: admit many per theory, named
  5893 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5894 
  5895 * print_goals: optional output of const types (set show_consts and
  5896 show_types);
  5897 
  5898 * improved output of warnings (###) and errors (***);
  5899 
  5900 * subgoal_tac displays a warning if the new subgoal has type variables;
  5901 
  5902 * removed old README and Makefiles;
  5903 
  5904 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5905 
  5906 * removed obsolete init_pps and init_database;
  5907 
  5908 * deleted the obsolete tactical STATE, which was declared by
  5909     fun STATE tacfun st = tacfun st st;
  5910 
  5911 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5912 (which abbreviates $HOME);
  5913 
  5914 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5915 use isatool fixseq to adapt your ML programs (this works for fully
  5916 qualified references to the Sequence structure only!);
  5917 
  5918 * use_thy no longer requires writable current directory; it always
  5919 reloads .ML *and* .thy file, if either one is out of date;
  5920 
  5921 
  5922 *** Classical Reasoner ***
  5923 
  5924 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5925 tactics that use classical reasoning to simplify a subgoal without
  5926 splitting it into several subgoals;
  5927 
  5928 * Safe_tac: like safe_tac but uses the default claset;
  5929 
  5930 
  5931 *** Simplifier ***
  5932 
  5933 * added simplification meta rules:
  5934     (asm_)(full_)simplify: simpset -> thm -> thm;
  5935 
  5936 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5937 logics (again);
  5938 
  5939 * added prems argument to simplification procedures;
  5940 
  5941 * HOL, FOL, ZF: added infix function `addsplits':
  5942   instead of `<simpset> setloop (split_tac <thms>)'
  5943   you can simply write `<simpset> addsplits <thms>'
  5944 
  5945 
  5946 *** Syntax ***
  5947 
  5948 * TYPE('a) syntax for type reflection terms;
  5949 
  5950 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5951 
  5952 * pretty printer: changed order of mixfix annotation preference (again!);
  5953 
  5954 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5955 
  5956 
  5957 *** HOL ***
  5958 
  5959 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5960   with `addloop' of the simplifier to faciliate case splitting in premises.
  5961 
  5962 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5963 
  5964 * HOL/Auth: new protocol proofs including some for the Internet
  5965   protocol TLS;
  5966 
  5967 * HOL/Map: new theory of `maps' a la VDM;
  5968 
  5969 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5970 cancelling out common nat summands from =, <, <= (in)equalities, or
  5971 differences; simplification procedures nat_cancel_factor for
  5972 cancelling common factor from =, <, <= (in)equalities over natural
  5973 sums; nat_cancel contains both kinds of procedures, it is installed by
  5974 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5975 
  5976 * HOL/simplifier: terms of the form
  5977   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5978   are rewritten to
  5979   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5980   and those of the form
  5981   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5982   are rewritten to
  5983   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5984 
  5985 * HOL/datatype
  5986   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5987 
  5988   P(t_case f1 ... fn x) =
  5989      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5990         ...
  5991        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5992      )
  5993 
  5994   and a theorem `split_t_case_asm' of the form
  5995 
  5996   P(t_case f1 ... fn x) =
  5997     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5998         ...
  5999        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  6000      )
  6001   which can be added to a simpset via `addsplits'. The existing theorems
  6002   expand_list_case and expand_option_case have been renamed to
  6003   split_list_case and split_option_case.
  6004 
  6005 * HOL/Arithmetic:
  6006   - `pred n' is automatically converted to `n-1'.
  6007     Users are strongly encouraged not to use `pred' any longer,
  6008     because it will disappear altogether at some point.
  6009   - Users are strongly encouraged to write "0 < n" rather than
  6010     "n ~= 0". Theorems and proof tools have been modified towards this
  6011     `standard'.
  6012 
  6013 * HOL/Lists:
  6014   the function "set_of_list" has been renamed "set" (and its theorems too);
  6015   the function "nth" now takes its arguments in the reverse order and
  6016   has acquired the infix notation "!" as in "xs!n".
  6017 
  6018 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  6019 
  6020 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  6021   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  6022 
  6023 * HOL/record: extensible records with schematic structural subtyping
  6024 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  6025 still lacks various theorems and concrete record syntax;
  6026 
  6027 
  6028 *** HOLCF ***
  6029 
  6030 * removed "axioms" and "generated by" sections;
  6031 
  6032 * replaced "ops" section by extended "consts" section, which is capable of
  6033   handling the continuous function space "->" directly;
  6034 
  6035 * domain package:
  6036   . proves theorems immediately and stores them in the theory,
  6037   . creates hierachical name space,
  6038   . now uses normal mixfix annotations (instead of cinfix...),
  6039   . minor changes to some names and values (for consistency),
  6040   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  6041   . separator between mutual domain defs: changed "," to "and",
  6042   . improved handling of sort constraints;  now they have to
  6043     appear on the left-hand side of the equations only;
  6044 
  6045 * fixed LAM <x,y,zs>.b syntax;
  6046 
  6047 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  6048 adm (%x. P (t x)), where P is chainfinite and t continuous;
  6049 
  6050 
  6051 *** FOL and ZF ***
  6052 
  6053 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6054   with `addloop' of the simplifier to faciliate case splitting in premises.
  6055 
  6056 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6057 in HOL, they strip ALL and --> from proved theorems;
  6058 
  6059 
  6060 
  6061 New in Isabelle94-8 (May 1997)
  6062 ------------------------------
  6063 
  6064 *** General Changes ***
  6065 
  6066 * new utilities to build / run / maintain Isabelle etc. (in parts
  6067 still somewhat experimental); old Makefiles etc. still functional;
  6068 
  6069 * new 'Isabelle System Manual';
  6070 
  6071 * INSTALL text, together with ./configure and ./build scripts;
  6072 
  6073 * reimplemented type inference for greater efficiency, better error
  6074 messages and clean internal interface;
  6075 
  6076 * prlim command for dealing with lots of subgoals (an easier way of
  6077 setting goals_limit);
  6078 
  6079 
  6080 *** Syntax ***
  6081 
  6082 * supports alternative (named) syntax tables (parser and pretty
  6083 printer); internal interface is provided by add_modesyntax(_i);
  6084 
  6085 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6086 be used in conjunction with the Isabelle symbol font; uses the
  6087 "symbols" syntax table;
  6088 
  6089 * added token_translation interface (may translate name tokens in
  6090 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6091 the current print_mode); IMPORTANT: user print translation functions
  6092 are responsible for marking newly introduced bounds
  6093 (Syntax.mark_boundT);
  6094 
  6095 * token translations for modes "xterm" and "xterm_color" that display
  6096 names in bold, underline etc. or colors (which requires a color
  6097 version of xterm);
  6098 
  6099 * infixes may now be declared with names independent of their syntax;
  6100 
  6101 * added typed_print_translation (like print_translation, but may
  6102 access type of constant);
  6103 
  6104 
  6105 *** Classical Reasoner ***
  6106 
  6107 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6108 some limitations.  Blast_tac...
  6109   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6110   + ignores elimination rules that don't have the correct format
  6111         (the conclusion MUST be a formula variable)
  6112   + ignores types, which can make HOL proofs fail
  6113   + rules must not require higher-order unification, e.g. apply_type in ZF
  6114     [message "Function Var's argument not a bound variable" relates to this]
  6115   + its proof strategy is more general but can actually be slower
  6116 
  6117 * substitution with equality assumptions no longer permutes other
  6118 assumptions;
  6119 
  6120 * minor changes in semantics of addafter (now called addaltern); renamed
  6121 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6122 (and access functions for it);
  6123 
  6124 * improved combination of classical reasoner and simplifier:
  6125   + functions for handling clasimpsets
  6126   + improvement of addss: now the simplifier is called _after_ the
  6127     safe steps.
  6128   + safe variant of addss called addSss: uses safe simplifications
  6129     _during_ the safe steps. It is more complete as it allows multiple
  6130     instantiations of unknowns (e.g. with slow_tac).
  6131 
  6132 *** Simplifier ***
  6133 
  6134 * added interface for simplification procedures (functions that
  6135 produce *proven* rewrite rules on the fly, depending on current
  6136 redex);
  6137 
  6138 * ordering on terms as parameter (used for ordered rewriting);
  6139 
  6140 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6141 
  6142 * the solver is now split into a safe and an unsafe part.
  6143 This should be invisible for the normal user, except that the
  6144 functions setsolver and addsolver have been renamed to setSolver and
  6145 addSolver; added safe_asm_full_simp_tac;
  6146 
  6147 
  6148 *** HOL ***
  6149 
  6150 * a generic induction tactic `induct_tac' which works for all datatypes and
  6151 also for type `nat';
  6152 
  6153 * a generic case distinction tactic `exhaust_tac' which works for all
  6154 datatypes and also for type `nat';
  6155 
  6156 * each datatype comes with a function `size';
  6157 
  6158 * patterns in case expressions allow tuple patterns as arguments to
  6159 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6160 
  6161 * primrec now also works with type nat;
  6162 
  6163 * recdef: a new declaration form, allows general recursive functions to be
  6164 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6165 
  6166 * the constant for negation has been renamed from "not" to "Not" to
  6167 harmonize with FOL, ZF, LK, etc.;
  6168 
  6169 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6170 infinite lists;
  6171 
  6172 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6173 
  6174 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6175 problems in commutative rings, using axiomatic type classes for + and *;
  6176 
  6177 * more examples in HOL/MiniML and HOL/Auth;
  6178 
  6179 * more default rewrite rules for quantifiers, union/intersection;
  6180 
  6181 * a new constant `arbitrary == @x.False';
  6182 
  6183 * HOLCF/IOA replaces old HOL/IOA;
  6184 
  6185 * HOLCF changes: derived all rules and arities
  6186   + axiomatic type classes instead of classes
  6187   + typedef instead of faking type definitions
  6188   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6189   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6190   + eliminated the types void, one, tr
  6191   + use unit lift and bool lift (with translations) instead of one and tr
  6192   + eliminated blift from Lift3.thy (use Def instead of blift)
  6193   all eliminated rules are derived as theorems --> no visible changes ;
  6194 
  6195 
  6196 *** ZF ***
  6197 
  6198 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6199 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6200 as ZF_cs addSIs [equalityI];
  6201 
  6202 
  6203 
  6204 New in Isabelle94-7 (November 96)
  6205 ---------------------------------
  6206 
  6207 * allowing negative levels (as offsets) in prlev and choplev;
  6208 
  6209 * super-linear speedup for large simplifications;
  6210 
  6211 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6212 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6213 FAIL); can suppress it using the command Delsimps (ex_simps @
  6214 all_simps); De Morgan laws are also now included, by default;
  6215 
  6216 * improved printing of ==>  :  ~:
  6217 
  6218 * new object-logic "Sequents" adds linear logic, while replacing LK
  6219 and Modal (thanks to Sara Kalvala);
  6220 
  6221 * HOL/Auth: correctness proofs for authentication protocols;
  6222 
  6223 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6224 examples on HOL/Auth);
  6225 
  6226 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6227 the rewriter and classical reasoner simultaneously;
  6228 
  6229 * function uresult no longer returns theorems in "standard" format;
  6230 regain previous version by: val uresult = standard o uresult;
  6231 
  6232 
  6233 
  6234 New in Isabelle94-6
  6235 -------------------
  6236 
  6237 * oracles -- these establish an interface between Isabelle and trusted
  6238 external reasoners, which may deliver results as theorems;
  6239 
  6240 * proof objects (in particular record all uses of oracles);
  6241 
  6242 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6243 
  6244 * "constdefs" section in theory files;
  6245 
  6246 * "primrec" section (HOL) no longer requires names;
  6247 
  6248 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6249 
  6250 
  6251 
  6252 New in Isabelle94-5
  6253 -------------------
  6254 
  6255 * reduced space requirements;
  6256 
  6257 * automatic HTML generation from theories;
  6258 
  6259 * theory files no longer require "..." (quotes) around most types;
  6260 
  6261 * new examples, including two proofs of the Church-Rosser theorem;
  6262