NEWS
author wenzelm
Wed Oct 15 21:15:35 2008 +0200 (2008-10-15)
changeset 28604 f36496b73227
parent 28563 21b3a00a3ff0
child 28605 12d6087ec18c
permissions -rw-r--r--
generic ATP manager based on threads (by Fabian Immler);
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Simplified main Isabelle executables, with less surprises on
    10 case-insensitive file-systems (such as Mac OS).
    11 
    12   - The main Isabelle tool wrapper is now called "isabelle" instead of
    13     "isatool."
    14 
    15   - The former "isabelle" alias for "isabelle-process" has been
    16     removed (should rarely occur to regular users).
    17 
    18   - The "Isabelle" alias for "isabelle-interface" has been removed.
    19 
    20 Within scripts and make files, the Isabelle environment variables
    21 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    22 respectively.  (The latter are still available as legacy feature.)
    23 
    24 Also note that user interfaces are now better wrapped as regular
    25 Isabelle tools instead of using the special isabelle-interface wrapper
    26 (which can be confusing if the interface is uninstalled or changed
    27 otherwise).  See "isabelle tty" and "isabelle emacs" for contemporary
    28 examples.
    29 
    30 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    31 purge installed copies of Isabelle executables and re-run "isabelle
    32 install -p ...", or use symlinks.
    33 
    34 * The Isabelle System Manual (system) has been updated, with formally
    35 checked references as hyperlinks.
    36 
    37 * Generalized Isar history, with support for linear undo, direct state
    38 addressing etc.
    39 
    40 * Recovered hiding of consts, which was accidentally broken in
    41 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
    42 makes c inaccessible; consider using ``hide (open) const c'' instead.
    43 
    44 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
    45 interface instead.
    46 
    47 
    48 *** Pure ***
    49 
    50 * Changed defaults for unify configuration options:
    51 
    52   unify_trace_bound = 50 (formerly 25)
    53   unify_search_bound = 60 (formerly 30)
    54 
    55 * Different bookkeeping for code equations:
    56   a) On theory merge, the last set of code equations for a particular constant
    57      is taken (in accordance with the policy applied by other parts of the
    58      code generator framework).
    59   b) Code equations stemming from explicit declarations (e.g. code attribute)
    60      gain priority over default code equations stemming from definition, primrec,
    61      fun etc.
    62   INCOMPATIBILITY.
    63 
    64 * Global versions of theorems stemming from classes do not carry
    65 a parameter prefix any longer.  INCOMPATIBILITY.
    66 
    67 * Dropped "locale (open)".  INCOMPATBILITY.
    68 
    69 * Interpretation commands no longer attempt to simplify goal.
    70 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
    71 methods intro_locales and unfold_locales to clarify.
    72 
    73 * Interpretation commands no longer accept interpretation attributes.
    74 INCOMPATBILITY.
    75 
    76 * Command 'instance': attached definitions no longer accepted.
    77 INCOMPATIBILITY, use proper 'instantiation' target.
    78 
    79 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
    80 
    81 * The 'axiomatization' command now only works within a global theory
    82 context.  INCOMPATIBILITY.
    83 
    84 
    85 *** Document preparation ***
    86 
    87 * Antiquotation @{lemma} now imitates a regular terminal proof,
    88 demanding keyword 'by' and supporting the full method expression
    89 syntax just like the Isar command 'by'.
    90 
    91 
    92 *** HOL ***
    93 
    94 * Unified theorem tables for both code code generators.  Thus
    95 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
    96 
    97 * Constant "undefined" replaces "arbitrary" in most occurences.
    98 
    99 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   100 Posix processes.  Avoids forking of the ML process, can be costly for
   101 long-lived operations due to garbage collection.  New thread
   102 based-implementation also works smoothly on non-Unix platforms
   103 (Cygwin).  Provers are no longer hardwired, but defined within the
   104 theory via plain ML wrapper functions.
   105 
   106 * Wrapper scripts for remote SystemOnTPTP service allows to use
   107 sledgehammer without local ATP installation (Vampire etc.).  See also
   108 ISABELLE_HOME/contrib/SystemOnTPTP and the VAMPIRE_HOME setting
   109 variable.  Other provers may be included via suitable ML wrappers, see
   110 also src/HOL/ATP_Linkup.thy.
   111 
   112 * Normalization by evaluation now allows non-leftlinear equations.
   113 Declare with attribute [code nbe].
   114 
   115 * Command "value" now integrates different evaluation
   116 mechanisms.  The result of the first successful evaluation mechanism
   117 is printed.  In square brackets a particular named evaluation
   118 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   119 further src/HOL/ex/Eval_Examples.thy.
   120 
   121 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   122 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   123 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   124 
   125 * HOL/Orderings: added class "preorder" as superclass of "order".
   126 INCOMPATIBILITY: Instantiation proofs for order, linorder
   127 etc. slightly changed.  Some theorems named order_class.* now named
   128 preorder_class.*.
   129 
   130 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   131 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   132 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   133 of lemmas from Divides has been generalized from nat to class
   134 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   135 renames resulting from duplicate elimination:
   136 
   137     dvd_def_mod ~>          dvd_eq_mod_eq_0
   138     zero_dvd_iff ~>         dvd_0_left_iff
   139     dvd_0 ~>                dvd_0_right
   140     DIVISION_BY_ZERO_DIV ~> div_by_0
   141     DIVISION_BY_ZERO_MOD ~> mod_by_0
   142     mult_div ~>             div_mult_self2_is_id
   143     mult_mod ~>             mod_mult_self2_is_0
   144 
   145 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   146 zlcm (for int); carried together from various gcd/lcm developements in
   147 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   148 corresponding theorems renamed accordingly.  INCOMPATIBILY.  To
   149 recover tupled syntax, use syntax declarations like:
   150 
   151     hide (open) const gcd
   152     abbreviation gcd where
   153       "gcd == (%(a, b). GCD.gcd a b)"
   154     notation (output)
   155       GCD.gcd ("gcd '(_, _')")
   156 
   157 (analogously for lcm, zgcd, zlcm).
   158 
   159 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   160 
   161 * New ML antiquotation @{code}: takes constant as argument, generates
   162 corresponding code in background and inserts name of the corresponding
   163 resulting ML value/function/datatype constructor binding in place.
   164 All occurrences of @{code} with a single ML block are generated
   165 simultaneously.  Provides a generic and safe interface for
   166 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   167 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   168 application.  In future you ought refrain from ad-hoc compiling
   169 generated SML code on the ML toplevel.  Note that (for technical
   170 reasons) @{code} cannot refer to constants for which user-defined
   171 serializations are set.  Refer to the corresponding ML counterpart
   172 directly in that cases.
   173 
   174 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   175 Complex_Main.thy remain as they are.
   176 
   177 * New image HOL-Plain provides a minimal HOL with the most important
   178 tools available (inductive, datatype, primrec, ...).  By convention
   179 the corresponding theory Plain should be ancestor of every further
   180 (library) theory.  Some library theories now have ancestor Plain
   181 (instead of Main), thus theory Main occasionally has to be imported
   182 explicitly.
   183 
   184 * The metis method now fails in the usual manner, rather than raising
   185 an exception, if it determines that it cannot prove the theorem.
   186 
   187 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   188 as the structured Isar versions "cases" and "induct", cf. the
   189 corresponding "cases" and "induct" attributes.  Mutual induction rules
   190 are now presented as a list of individual projections
   191 (e.g. foo_bar.inducts for types foo and bar); the old format with
   192 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   193 rare situations a different rule is selected --- notably nested tuple
   194 elimination instead of former prod.exhaust: use explicit (case_tac t
   195 rule: prod.exhaust) here.
   196 
   197 * Attributes "cases", "induct", "coinduct" support "del" option.
   198 
   199 * Removed fact "case_split_thm", which duplicates "case_split".
   200 
   201 * Command 'rep_datatype': instead of theorem names the command now
   202 takes a list of terms denoting the constructors of the type to be
   203 represented as datatype.  The characteristic theorems have to be
   204 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   205 have disappeared in favour of existing ones:
   206 
   207     unit_induct                 ~> unit.induct
   208     prod_induct                 ~> prod.induct
   209     sum_induct                  ~> sum.induct
   210     Suc_Suc_eq                  ~> nat.inject
   211     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   212 
   213 * Library/Nat_Infinity: added addition, numeral syntax and more
   214 instantiations for algebraic structures.  Removed some duplicate
   215 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   216 
   217 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   218 menu.
   219 
   220 
   221 *** HOL-Algebra ***
   222 
   223 * New locales for orders and lattices where the equivalence relation
   224   is not restricted to equality.  INCOMPATIBILITY: all order and
   225   lattice locales use a record structure with field eq for the
   226   equivalence.
   227 
   228 * New theory of factorial domains.
   229 
   230 * Units_l_inv and Units_r_inv are now simprules by default.
   231 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   232 and/or r_inv will now also require deletion of these lemmas.
   233 
   234 * Renamed the following theorems.  INCOMPATIBILITY.
   235 UpperD ~> Upper_memD
   236 LowerD ~> Lower_memD
   237 least_carrier ~> least_closed
   238 greatest_carrier ~> greatest_closed
   239 greatest_Lower_above ~> greatest_Lower_below
   240 one_zero ~> carrier_one_zero
   241 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   242 
   243 
   244 *** HOL-NSA ***
   245 
   246 * Created new image HOL-NSA, containing theories of nonstandard
   247 analysis which were previously part of HOL-Complex.  Entry point
   248 Hyperreal.thy remains valid, but theories formerly using
   249 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   250 
   251 
   252 *** ZF ***
   253 
   254 * Proof of Zorn's Lemma for partial orders.
   255 
   256 
   257 *** ML ***
   258 
   259 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   260 to 'a -> thm, while results are always tagged with an authentic oracle
   261 name.  The Isar command 'oracle' is now polymorphic, no argument type
   262 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   263 accordingly.  Note that extra performance may be gained by producing
   264 the cterm carefully, avoiding slow Thm.cterm_of.
   265 
   266 * ML bindings produced via Isar commands are stored within the Isar
   267 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   268 become thread-safe and work with undo as expected (concerning
   269 top-level bindings, not side-effects on global references).
   270 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   271 compiler at runtime; really global bindings need to be given outside a
   272 theory. [Poly/ML 5.2 or later]
   273 
   274 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   275 context. Top-level ML bindings are stored within the proof context in
   276 a purely sequential fashion, disregarding the nested proof structure.
   277 ML bindings introduced by 'ML_prf' are discarded at the end of the
   278 proof.  [Poly/ML 5.2 or later]
   279 
   280 * Generic Toplevel.add_hook interface allows to analyze the result of
   281 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   282 for theorem dependency output of transactions resulting in a new
   283 theory state.
   284 
   285 * Name bindings in higher specification mechanisms (notably
   286 LocalTheory.define, LocalTheory.note, and derived packages) are now
   287 formalized as type Name.binding, replacing old bstring.
   288 INCOMPATIBILITY, need to wrap strings via Name.binding function, see
   289 also Name.name_of.  Packages should pass name bindings given by the
   290 user to underlying specification mechanisms; this enables precise
   291 tracking of source positions, for example.
   292 
   293 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   294 LocalTheory.note etc.) now refer to the *full* internal name, not the
   295 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   296 
   297 * Rules and tactics that read instantiations (read_instantiate,
   298 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   299 context, which is required for parsing and type-checking.  Moreover,
   300 the variables are specified as plain indexnames, not string encodings
   301 thereof.  INCOMPATIBILITY.
   302 
   303 * Disposed old type and term read functions (Sign.read_def_typ,
   304 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   305 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   306 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   307 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   308 resort for legacy applications.
   309 
   310 * Antiquotations: block-structured compilation context indicated by
   311 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   312 
   313   @{let ?pat = term}                      - term abbreviation (HO matching)
   314   @{note name = fact}                     - fact abbreviation
   315   @{thm fact}                             - singleton fact (with attributes)
   316   @{thms fact}                            - general fact (with attributes)
   317   @{lemma prop by method}                 - singleton goal
   318   @{lemma prop by meth1 meth2}            - singleton goal
   319   @{lemma prop1 ... propN by method}      - general goal
   320   @{lemma prop1 ... propN by meth1 meth2} - general goal
   321   @{lemma (open) ...}                     - open derivation
   322 
   323 
   324 *** System ***
   325 
   326 * Multithreading for Poly/ML 5.1 is no longer supported, only for
   327 Poly/ML 5.2 or later.
   328 
   329 * The Isabelle "emacs" tool provides a specific interface to invoke
   330 Proof General / Emacs, with more explicit failure if that is not
   331 installed (the old isabelle-interface script silently falls back on
   332 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   333 installation location of the Proof General distribution.
   334 
   335 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   336 the Isabelle process into a JVM/Scala application.  See
   337 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   338 process wrapper has been discontinued.)
   339 
   340 * Status messages (with exact source position information) are
   341 emitted, if proper markup print mode is enabled.  This allows
   342 user-interface components to provide detailed feedback on internal
   343 prover operations.
   344 
   345 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   346 
   347 
   348 
   349 New in Isabelle2008 (June 2008)
   350 -------------------------------
   351 
   352 *** General ***
   353 
   354 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   355 and updated, with formally checked references as hyperlinks.
   356 
   357 * Theory loader: use_thy (and similar operations) no longer set the
   358 implicit ML context, which was occasionally hard to predict and in
   359 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   360 provides a proper context already.
   361 
   362 * Theory loader: old-style ML proof scripts being *attached* to a thy
   363 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   364 'use' within a theory file will do the job.
   365 
   366 * Name space merge now observes canonical order, i.e. the second space
   367 is inserted into the first one, while existing entries in the first
   368 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   369 swap theory imports.
   370 
   371 * Syntax: symbol \<chi> is now considered a letter.  Potential
   372 INCOMPATIBILITY in identifier syntax etc.
   373 
   374 * Outer syntax: string tokens no longer admit escaped white space,
   375 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   376 white space without escapes.
   377 
   378 * Outer syntax: string tokens may contain arbitrary character codes
   379 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   380 "foo_bar".
   381 
   382 
   383 *** Pure ***
   384 
   385 * Context-dependent token translations.  Default setup reverts locally
   386 fixed variables, and adds hilite markup for undeclared frees.
   387 
   388 * Unused theorems can be found using the new command 'unused_thms'.
   389 There are three ways of invoking it:
   390 
   391 (1) unused_thms
   392      Only finds unused theorems in the current theory.
   393 
   394 (2) unused_thms thy_1 ... thy_n -
   395      Finds unused theorems in the current theory and all of its ancestors,
   396      excluding the theories thy_1 ... thy_n and all of their ancestors.
   397 
   398 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   399      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   400      their ancestors, excluding the theories thy_1 ... thy_n and all of
   401      their ancestors.
   402 
   403 In order to increase the readability of the list produced by
   404 unused_thms, theorems that have been created by a particular instance
   405 of a theory command such as 'inductive' or 'function' are considered
   406 to belong to the same "group", meaning that if at least one theorem in
   407 this group is used, the other theorems in the same group are no longer
   408 reported as unused.  Moreover, if all theorems in the group are
   409 unused, only one theorem in the group is displayed.
   410 
   411 Note that proof objects have to be switched on in order for
   412 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   413 usually the case when using Proof General with the default settings).
   414 
   415 * Authentic naming of facts disallows ad-hoc overwriting of previous
   416 theorems within the same name space.  INCOMPATIBILITY, need to remove
   417 duplicate fact bindings, or even accidental fact duplications.  Note
   418 that tools may maintain dynamically scoped facts systematically, using
   419 PureThy.add_thms_dynamic.
   420 
   421 * Command 'hide' now allows to hide from "fact" name space as well.
   422 
   423 * Eliminated destructive theorem database, simpset, claset, and
   424 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   425 update of theories within ML code.
   426 
   427 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   428 INCOMPATIBILITY, object-logics depending on former Pure require
   429 additional setup PureThy.old_appl_syntax_setup; object-logics
   430 depending on former CPure need to refer to Pure.
   431 
   432 * Commands 'use' and 'ML' are now purely functional, operating on
   433 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   434 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   435 INCOMPATIBILITY.
   436 
   437 * Command 'setup': discontinued implicit version with ML reference.
   438 
   439 * Instantiation target allows for simultaneous specification of class
   440 instance operations together with an instantiation proof.
   441 Type-checking phase allows to refer to class operations uniformly.
   442 See src/HOL/Complex/Complex.thy for an Isar example and
   443 src/HOL/Library/Eval.thy for an ML example.
   444 
   445 * Indexing of literal facts: be more serious about including only
   446 facts from the visible specification/proof context, but not the
   447 background context (locale etc.).  Affects `prop` notation and method
   448 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   449 situations.
   450 
   451 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   452 "(open)" option, which used to expose internal bound variables to the
   453 proof text.
   454 
   455 * Isar statements: removed obsolete case "rule_context".
   456 INCOMPATIBILITY, better use explicit fixes/assumes.
   457 
   458 * Locale proofs: default proof step now includes 'unfold_locales';
   459 hence 'proof' without argument may be used to unfold locale
   460 predicates.
   461 
   462 
   463 *** Document preparation ***
   464 
   465 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   466 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   467 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   468 spot); renamed link color from "darkblue" to "linkcolor" (default
   469 value unchanged, can be redefined via \definecolor); no longer sets
   470 "a4paper" option (unnecessary or even intrusive).
   471 
   472 * Antiquotation @{lemma A method} proves proposition A by the given
   473 method (either a method name or a method name plus (optional) method
   474 arguments in parentheses) and prints A just like @{prop A}.
   475 
   476 
   477 *** HOL ***
   478 
   479 * New primrec package.  Specification syntax conforms in style to
   480 definition/function/....  No separate induction rule is provided.  The
   481 "primrec" command distinguishes old-style and new-style specifications
   482 by syntax.  The former primrec package is now named OldPrimrecPackage.
   483 When adjusting theories, beware: constants stemming from new-style
   484 primrec specifications have authentic syntax.
   485 
   486 * Metis prover is now an order of magnitude faster, and also works
   487 with multithreading.
   488 
   489 * Metis: the maximum number of clauses that can be produced from a
   490 theorem is now given by the attribute max_clauses.  Theorems that
   491 exceed this number are ignored, with a warning printed.
   492 
   493 * Sledgehammer no longer produces structured proofs by default. To
   494 enable, declare [[sledgehammer_full = true]].  Attributes
   495 reconstruction_modulus, reconstruction_sorts renamed
   496 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   497 
   498 * Method "induct_scheme" derives user-specified induction rules
   499 from well-founded induction and completeness of patterns. This factors
   500 out some operations that are done internally by the function package
   501 and makes them available separately.  See
   502 src/HOL/ex/Induction_Scheme.thy for examples.
   503 
   504 * More flexible generation of measure functions for termination
   505 proofs: Measure functions can be declared by proving a rule of the
   506 form "is_measure f" and giving it the [measure_function] attribute.
   507 The "is_measure" predicate is logically meaningless (always true), and
   508 just guides the heuristic.  To find suitable measure functions, the
   509 termination prover sets up the goal "is_measure ?f" of the appropriate
   510 type and generates all solutions by prolog-style backwards proof using
   511 the declared rules.
   512 
   513 This setup also deals with rules like 
   514 
   515   "is_measure f ==> is_measure (list_size f)"
   516 
   517 which accommodates nested datatypes that recurse through lists.
   518 Similar rules are predeclared for products and option types.
   519 
   520 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   521 
   522   INCOMPATIBILITIES:
   523 
   524   - Definitions of overloaded constants on sets have to be replaced by
   525     definitions on => and bool.
   526 
   527   - Some definitions of overloaded operators on sets can now be proved
   528     using the definitions of the operators on => and bool.  Therefore,
   529     the following theorems have been renamed:
   530 
   531       subset_def   -> subset_eq
   532       psubset_def  -> psubset_eq
   533       set_diff_def -> set_diff_eq
   534       Compl_def    -> Compl_eq
   535       Sup_set_def  -> Sup_set_eq
   536       Inf_set_def  -> Inf_set_eq
   537       sup_set_def  -> sup_set_eq
   538       inf_set_def  -> inf_set_eq
   539 
   540   - Due to the incompleteness of the HO unification algorithm, some
   541     rules such as subst may require manual instantiation, if some of
   542     the unknowns in the rule is a set.
   543 
   544   - Higher order unification and forward proofs:
   545     The proof pattern
   546 
   547       have "P (S::'a set)" <...>
   548       then have "EX S. P S" ..
   549 
   550     no longer works (due to the incompleteness of the HO unification
   551     algorithm) and must be replaced by the pattern
   552 
   553       have "EX S. P S"
   554       proof
   555         show "P S" <...>
   556       qed
   557 
   558   - Calculational reasoning with subst (or similar rules):
   559     The proof pattern
   560 
   561       have "P (S::'a set)" <...>
   562       also have "S = T" <...>
   563       finally have "P T" .
   564 
   565     no longer works (for similar reasons as the previous example) and
   566     must be replaced by something like
   567 
   568       have "P (S::'a set)" <...>
   569       moreover have "S = T" <...>
   570       ultimately have "P T" by simp
   571 
   572   - Tactics or packages written in ML code:
   573     Code performing pattern matching on types via
   574 
   575       Type ("set", [T]) => ...
   576 
   577     must be rewritten. Moreover, functions like strip_type or
   578     binder_types no longer return the right value when applied to a
   579     type of the form
   580 
   581       T1 => ... => Tn => U => bool
   582 
   583     rather than
   584 
   585       T1 => ... => Tn => U set
   586 
   587 * Merged theories Wellfounded_Recursion, Accessible_Part and
   588 Wellfounded_Relations to theory Wellfounded.
   589 
   590 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   591 
   592 * Class finite no longer treats UNIV as class parameter.  Use class
   593 enum from theory Library/Enum instead to achieve a similar effect.
   594 INCOMPATIBILITY.
   595 
   596 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   597 and "Cons".  INCOMPATIBILITY.
   598 
   599 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   600 Potential INCOMPATIBILITY.
   601 
   602 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   603 injective_fst_snd removed, use split_eta and prod_eqI instead.
   604 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   605 
   606 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   607 the same name in theory Orderings:
   608 
   609   less_trans
   610   less_linear
   611   le_imp_less_or_eq
   612   le_less_trans
   613   less_le_trans
   614   less_not_sym
   615   less_asym
   616 
   617 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   618 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   619 and different variable names.
   620 
   621 * Library/Option_ord.thy: Canonical order on option type.
   622 
   623 * Library/RBT.thy: Red-black trees, an efficient implementation of
   624 finite maps.
   625 
   626 * Library/Countable.thy: Type class for countable types.
   627 
   628 * Theory Int: The representation of numerals has changed.  The infix
   629 operator BIT and the bit datatype with constructors B0 and B1 have
   630 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   631 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   632 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   633 accordingly.
   634 
   635 * Theory Nat: definition of <= and < on natural numbers no longer
   636 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   637 le_def and less_def have disappeared.  Consider lemmas not_less
   638 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   639 
   640 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   641 (whose purpose mainly is for various fold_set functionals) have been
   642 abandoned in favor of the existing algebraic classes
   643 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   644 lower_semilattice (resp. upper_semilattice) and linorder.
   645 INCOMPATIBILITY.
   646 
   647 * Theory Transitive_Closure: induct and cases rules now declare proper
   648 case_names ("base" and "step").  INCOMPATIBILITY.
   649 
   650 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   651 lattices.  The form set-specific version is available as
   652 Inductive.lfp_ordinal_induct_set.
   653 
   654 * Renamed theorems "power.simps" to "power_int.simps".
   655 INCOMPATIBILITY.
   656 
   657 * Class semiring_div provides basic abstract properties of semirings
   658 with division and modulo operations.  Subsumes former class dvd_mod.
   659 
   660 * Merged theories IntDef, Numeral and IntArith into unified theory
   661 Int.  INCOMPATIBILITY.
   662 
   663 * Theory Library/Code_Index: type "index" now represents natural
   664 numbers rather than integers.  INCOMPATIBILITY.
   665 
   666 * New class "uminus" with operation "uminus" (split of from class
   667 "minus" which now only has operation "minus", binary).
   668 INCOMPATIBILITY.
   669 
   670 * Constants "card", "internal_split", "option_map" now with authentic
   671 syntax.  INCOMPATIBILITY.
   672 
   673 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   674 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   675 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   676 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   677 Sup_set_def, le_def, less_def, option_map_def now with object
   678 equality.  INCOMPATIBILITY.
   679 
   680 * Records. Removed K_record, and replaced it by pure lambda term
   681 %x. c. The simplifier setup is now more robust against eta expansion.
   682 INCOMPATIBILITY: in cases explicitly referring to K_record.
   683 
   684 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   685 
   686 * Library/ListVector: new theory of arithmetic vector operations.
   687 
   688 * Library/Order_Relation: new theory of various orderings as sets of
   689 pairs.  Defines preorders, partial orders, linear orders and
   690 well-orders on sets and on types.
   691 
   692 
   693 *** ZF ***
   694 
   695 * Renamed some theories to allow to loading both ZF and HOL in the
   696 same session:
   697 
   698   Datatype  -> Datatype_ZF
   699   Inductive -> Inductive_ZF
   700   Int       -> Int_ZF
   701   IntDiv    -> IntDiv_ZF
   702   Nat       -> Nat_ZF
   703   List      -> List_ZF
   704   Main      -> Main_ZF
   705 
   706 INCOMPATIBILITY: ZF theories that import individual theories below
   707 Main might need to be adapted.  Regular theory Main is still
   708 available, as trivial extension of Main_ZF.
   709 
   710 
   711 *** ML ***
   712 
   713 * ML within Isar: antiquotation @{const name} or @{const
   714 name(typargs)} produces statically-checked Const term.
   715 
   716 * Functor NamedThmsFun: data is available to the user as dynamic fact
   717 (of the same name).  Removed obsolete print command.
   718 
   719 * Removed obsolete "use_legacy_bindings" function.
   720 
   721 * The ``print mode'' is now a thread-local value derived from a global
   722 template (the former print_mode reference), thus access becomes
   723 non-critical.  The global print_mode reference is for session
   724 management only; user-code should use print_mode_value,
   725 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   726 
   727 * Functions system/system_out provide a robust way to invoke external
   728 shell commands, with propagation of interrupts (requires Poly/ML 5.2).
   729 Do not use OS.Process.system etc. from the basis library!
   730 
   731 
   732 *** System ***
   733 
   734 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   735 in accordance with Proof General 3.7, which prefers GNU emacs.
   736 
   737 * isatool tty runs Isabelle process with plain tty interaction;
   738 optional line editor may be specified via ISABELLE_LINE_EDITOR
   739 setting, the default settings attempt to locate "ledit" and "rlwrap".
   740 
   741 * isatool browser now works with Cygwin as well, using general
   742 "javapath" function defined in Isabelle process environment.
   743 
   744 * YXML notation provides a simple and efficient alternative to
   745 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
   746 isatool yxml as described in the Isabelle system manual.
   747 
   748 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   749 provides general wrapper for managing an Isabelle process in a robust
   750 fashion, with ``cooked'' output from stdin/stderr.
   751 
   752 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   753 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   754 
   755 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
   756 way of changing the user's settings is via
   757 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   758 script.
   759 
   760 * Multithreading.max_threads := 0 refers to the number of actual CPU
   761 cores of the underlying machine, which is a good starting point for
   762 optimal performance tuning.  The corresponding usedir option -M allows
   763 "max" as an alias for "0".  WARNING: does not work on certain versions
   764 of Mac OS (with Poly/ML 5.1).
   765 
   766 * isabelle-process: non-ML sessions are run with "nice", to reduce the
   767 adverse effect of Isabelle flooding interactive front-ends (notably
   768 ProofGeneral / XEmacs).
   769 
   770 
   771 
   772 New in Isabelle2007 (November 2007)
   773 -----------------------------------
   774 
   775 *** General ***
   776 
   777 * More uniform information about legacy features, notably a
   778 warning/error of "Legacy feature: ...", depending on the state of the
   779 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   780 legacy features will disappear eventually.
   781 
   782 * Theory syntax: the header format ``theory A = B + C:'' has been
   783 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   784 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   785 
   786 * Theory syntax: the old non-Isar theory file format has been
   787 discontinued altogether.  Note that ML proof scripts may still be used
   788 with Isar theories; migration is usually quite simple with the ML
   789 function use_legacy_bindings.  INCOMPATIBILITY.
   790 
   791 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   792 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   793 quotes.
   794 
   795 * Theory loader: be more serious about observing the static theory
   796 header specifications (including optional directories), but not the
   797 accidental file locations of previously successful loads.  The strict
   798 update policy of former update_thy is now already performed by
   799 use_thy, so the former has been removed; use_thys updates several
   800 theories simultaneously, just as 'imports' within a theory header
   801 specification, but without merging the results.  Potential
   802 INCOMPATIBILITY: may need to refine theory headers and commands
   803 ROOT.ML which depend on load order.
   804 
   805 * Theory loader: optional support for content-based file
   806 identification, instead of the traditional scheme of full physical
   807 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   808 (cf. the system manual).  The new scheme allows to work with
   809 non-finished theories in persistent session images, such that source
   810 files may be moved later on without requiring reloads.
   811 
   812 * Theory loader: old-style ML proof scripts being *attached* to a thy
   813 file (with the same base name as the theory) are considered a legacy
   814 feature, which will disappear eventually. Even now, the theory loader
   815 no longer maintains dependencies on such files.
   816 
   817 * Syntax: the scope for resolving ambiguities via type-inference is
   818 now limited to individual terms, instead of whole simultaneous
   819 specifications as before. This greatly reduces the complexity of the
   820 syntax module and improves flexibility by separating parsing and
   821 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   822 'fixes' etc.) are required in rare situations.
   823 
   824 * Syntax: constants introduced by new-style packages ('definition',
   825 'abbreviation' etc.) are passed through the syntax module in
   826 ``authentic mode''. This means that associated mixfix annotations
   827 really stick to such constants, independently of potential name space
   828 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   829 trees are represented slightly differently, may need to adapt syntax
   830 translations accordingly. Use CONST marker in 'translations' and
   831 @{const_syntax} antiquotation in 'parse_translation' etc.
   832 
   833 * Legacy goal package: reduced interface to the bare minimum required
   834 to keep existing proof scripts running.  Most other user-level
   835 functions are now part of the OldGoals structure, which is *not* open
   836 by default (consider isatool expandshort before open OldGoals).
   837 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   838 these tend to cause confusion about the actual goal (!) context being
   839 used here, which is not necessarily the same as the_context().
   840 
   841 * Command 'find_theorems': supports "*" wild-card in "name:"
   842 criterion; "with_dups" option.  Certain ProofGeneral versions might
   843 support a specific search form (see ProofGeneral/CHANGES).
   844 
   845 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   846 by default, which means that "prems" (and also "fixed variables") are
   847 suppressed from proof state output.  Note that the ProofGeneral
   848 settings mechanism allows to change and save options persistently, but
   849 older versions of Isabelle will fail to start up if a negative prems
   850 limit is imposed.
   851 
   852 * Local theory targets may be specified by non-nested blocks of
   853 ``context/locale/class ... begin'' followed by ``end''.  The body may
   854 contain definitions, theorems etc., including any derived mechanism
   855 that has been implemented on top of these primitives.  This concept
   856 generalizes the existing ``theorem (in ...)'' towards more versatility
   857 and scalability.
   858 
   859 * Proof General interface: proper undo of final 'end' command;
   860 discontinued Isabelle/classic mode (ML proof scripts).
   861 
   862 
   863 *** Document preparation ***
   864 
   865 * Added antiquotation @{theory name} which prints the given name,
   866 after checking that it refers to a valid ancestor theory in the
   867 current context.
   868 
   869 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   870 check the given source text as ML type/structure, printing verbatim.
   871 
   872 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   873 "c args == rhs" given in the current context.  (Any number of
   874 arguments may be given on the LHS.)
   875 
   876 
   877 *** Pure ***
   878 
   879 * The 'class' package offers a combination of axclass and locale to
   880 achieve Haskell-like type classes in Isabelle.  Definitions and
   881 theorems within a class context produce both relative results (with
   882 implicit parameters according to the locale context), and polymorphic
   883 constants with qualified polymorphism (according to the class
   884 context).  Within the body context of a 'class' target, a separate
   885 syntax layer ("user space type system") takes care of converting
   886 between global polymorphic consts and internal locale representation.
   887 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   888 "isatool doc classes" provides a tutorial.
   889 
   890 * Generic code generator framework allows to generate executable
   891 code for ML and Haskell (including Isabelle classes).  A short usage
   892 sketch:
   893 
   894     internal compilation:
   895         export_code <list of constants (term syntax)> in SML
   896     writing SML code to a file:
   897         export_code <list of constants (term syntax)> in SML <filename>
   898     writing OCaml code to a file:
   899         export_code <list of constants (term syntax)> in OCaml <filename>
   900     writing Haskell code to a bunch of files:
   901         export_code <list of constants (term syntax)> in Haskell <filename>
   902 
   903     evaluating closed propositions to True/False using code generation:
   904         method ``eval''
   905 
   906 Reasonable default setup of framework in HOL.
   907 
   908 Theorem attributs for selecting and transforming function equations theorems:
   909 
   910     [code fun]:        select a theorem as function equation for a specific constant
   911     [code fun del]:    deselect a theorem as function equation for a specific constant
   912     [code inline]:     select an equation theorem for unfolding (inlining) in place
   913     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   914 
   915 User-defined serializations (target in {SML, OCaml, Haskell}):
   916 
   917     code_const <and-list of constants (term syntax)>
   918       {(target) <and-list of const target syntax>}+
   919 
   920     code_type <and-list of type constructors>
   921       {(target) <and-list of type target syntax>}+
   922 
   923     code_instance <and-list of instances>
   924       {(target)}+
   925         where instance ::= <type constructor> :: <class>
   926 
   927     code_class <and_list of classes>
   928       {(target) <and-list of class target syntax>}+
   929         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   930 
   931 code_instance and code_class only are effective to target Haskell.
   932 
   933 For example usage see src/HOL/ex/Codegenerator.thy and
   934 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   935 generation from Isabelle/HOL theories is available via "isatool doc
   936 codegen".
   937 
   938 * Code generator: consts in 'consts_code' Isar commands are now
   939 referred to by usual term syntax (including optional type
   940 annotations).
   941 
   942 * Command 'no_translations' removes translation rules from theory
   943 syntax.
   944 
   945 * Overloaded definitions are now actually checked for acyclic
   946 dependencies.  The overloading scheme is slightly more general than
   947 that of Haskell98, although Isabelle does not demand an exact
   948 correspondence to type class and instance declarations.
   949 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   950 exotic versions of overloading -- at the discretion of the user!
   951 
   952 Polymorphic constants are represented via type arguments, i.e. the
   953 instantiation that matches an instance against the most general
   954 declaration given in the signature.  For example, with the declaration
   955 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   956 as c(nat).  Overloading is essentially simultaneous structural
   957 recursion over such type arguments.  Incomplete specification patterns
   958 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   959 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   960 Command 'print_theory' outputs the normalized system of recursive
   961 equations, see section "definitions".
   962 
   963 * Configuration options are maintained within the theory or proof
   964 context (with name and type bool/int/string), providing a very simple
   965 interface to a poor-man's version of general context data.  Tools may
   966 declare options in ML (e.g. using Attrib.config_int) and then refer to
   967 these values using Config.get etc.  Users may change options via an
   968 associated attribute of the same name.  This form of context
   969 declaration works particularly well with commands 'declare' or
   970 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   971 very easy to avoid global references, which would not observe Isar
   972 toplevel undo/redo and fail to work with multithreading.
   973 
   974 Various global ML references of Pure and HOL have been turned into
   975 configuration options:
   976 
   977   Unify.search_bound		unify_search_bound
   978   Unify.trace_bound		unify_trace_bound
   979   Unify.trace_simp		unify_trace_simp
   980   Unify.trace_types		unify_trace_types
   981   Simplifier.simp_depth_limit	simp_depth_limit
   982   Blast.depth_limit		blast_depth_limit
   983   DatatypeProp.dtK		datatype_distinctness_limit
   984   fast_arith_neq_limit  	fast_arith_neq_limit
   985   fast_arith_split_limit	fast_arith_split_limit
   986 
   987 * Named collections of theorems may be easily installed as context
   988 data using the functor NamedThmsFun (see also
   989 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   990 attributes; there is also a toplevel print command.  This facility is
   991 just a common case of general context data, which is the preferred way
   992 for anything more complex than just a list of facts in canonical
   993 order.
   994 
   995 * Isar: command 'declaration' augments a local theory by generic
   996 declaration functions written in ML.  This enables arbitrary content
   997 being added to the context, depending on a morphism that tells the
   998 difference of the original declaration context wrt. the application
   999 context encountered later on.
  1000 
  1001 * Isar: proper interfaces for simplification procedures.  Command
  1002 'simproc_setup' declares named simprocs (with match patterns, and body
  1003 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1004 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1005 
  1006 * Isar: an extra pair of brackets around attribute declarations
  1007 abbreviates a theorem reference involving an internal dummy fact,
  1008 which will be ignored later --- only the effect of the attribute on
  1009 the background context will persist.  This form of in-place
  1010 declarations is particularly useful with commands like 'declare' and
  1011 'using', for example ``have A using [[simproc a]] by simp''.
  1012 
  1013 * Isar: method "assumption" (and implicit closing of subproofs) now
  1014 takes simple non-atomic goal assumptions into account: after applying
  1015 an assumption as a rule the resulting subgoals are solved by atomic
  1016 assumption steps.  This is particularly useful to finish 'obtain'
  1017 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1018 without referring to the original premise "!!x. P x ==> thesis" in the
  1019 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1020 more permissive.
  1021 
  1022 * Isar: implicit use of prems from the Isar proof context is
  1023 considered a legacy feature.  Common applications like ``have A .''
  1024 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1025 referencing facts explicitly here improves readability and
  1026 maintainability of proof texts.
  1027 
  1028 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1029 the obtained context from the course of reasoning!  For example:
  1030 
  1031   assume "EX x y. A x & B y"   -- "any previous fact"
  1032   then guess x and y by clarify
  1033 
  1034 This technique is potentially adventurous, depending on the facts and
  1035 proof tools being involved here.
  1036 
  1037 * Isar: known facts from the proof context may be specified as literal
  1038 propositions, using ASCII back-quote syntax.  This works wherever
  1039 named facts used to be allowed so far, in proof commands, proof
  1040 methods, attributes etc.  Literal facts are retrieved from the context
  1041 according to unification of type and term parameters.  For example,
  1042 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1043 theorems in the current context, then these are valid literal facts:
  1044 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1045 
  1046 There is also a proof method "fact" which does the same composition
  1047 for explicit goal states, e.g. the following proof texts coincide with
  1048 certain special cases of literal facts:
  1049 
  1050   have "A" by fact                 ==  note `A`
  1051   have "A ==> B" by fact           ==  note `A ==> B`
  1052   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1053   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1054 
  1055 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1056 outer syntax.  Thus symbolic identifiers may be used without
  1057 additional white space in declarations like this: ``assume *: A''.
  1058 
  1059 * Isar: 'print_facts' prints all local facts of the current context,
  1060 both named and unnamed ones.
  1061 
  1062 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1063 
  1064   def x == "t" and y == "u"
  1065 
  1066 * Isar: added command 'unfolding', which is structurally similar to
  1067 'using', but affects both the goal state and facts by unfolding given
  1068 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1069 'unfolded' attribute may be replaced by first-class proof text.
  1070 
  1071 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1072 and command 'unfolding' now all support object-level equalities
  1073 (potentially conditional).  The underlying notion of rewrite rule is
  1074 analogous to the 'rule_format' attribute, but *not* that of the
  1075 Simplifier (which is usually more generous).
  1076 
  1077 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1078 premises of a theorem by n. Useful in conjunction with drule.
  1079 
  1080 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1081 method expression within a sandbox consisting of the first N
  1082 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1083 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1084 simplifies all new goals that emerge from applying rule foo to the
  1085 originally first one.
  1086 
  1087 * Isar: schematic goals are no longer restricted to higher-order
  1088 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1089 expected.
  1090 
  1091 * Isar: the conclusion of a long theorem statement is now either
  1092 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1093 (essentially a disjunction of cases with local parameters and
  1094 assumptions).  The latter allows to express general elimination rules
  1095 adequately; in this notation common elimination rules look like this:
  1096 
  1097   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1098     assumes "EX x. P x"
  1099     obtains x where "P x"
  1100 
  1101   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1102     assumes "A & B"
  1103     obtains A and B
  1104 
  1105   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1106     assumes "A | B"
  1107     obtains
  1108       A
  1109     | B
  1110 
  1111 The subsequent classical rules even refer to the formal "thesis"
  1112 explicitly:
  1113 
  1114   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1115     obtains "~ thesis"
  1116 
  1117   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1118     obtains "thesis ==> something"
  1119 
  1120 The actual proof of an 'obtains' statement is analogous to that of the
  1121 Isar proof element 'obtain', only that there may be several cases.
  1122 Optional case names may be specified in parentheses; these will be
  1123 available both in the present proof and as annotations in the
  1124 resulting rule, for later use with the 'cases' method (cf. attribute
  1125 case_names).
  1126 
  1127 * Isar: the assumptions of a long theorem statement are available as
  1128 "assms" fact in the proof context.  This is more appropriate than the
  1129 (historical) "prems", which refers to all assumptions of the current
  1130 context, including those from the target locale, proof body etc.
  1131 
  1132 * Isar: 'print_statement' prints theorems from the current theory or
  1133 proof context in long statement form, according to the syntax of a
  1134 top-level lemma.
  1135 
  1136 * Isar: 'obtain' takes an optional case name for the local context
  1137 introduction rule (default "that").
  1138 
  1139 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1140 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1141 to occur.
  1142 
  1143 * Pure: syntax "CONST name" produces a fully internalized constant
  1144 according to the current context.  This is particularly useful for
  1145 syntax translations that should refer to internal constant
  1146 representations independently of name spaces.
  1147 
  1148 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1149 instead of "FOO ". This allows multiple binder declarations to coexist
  1150 in the same context.  INCOMPATIBILITY.
  1151 
  1152 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1153 primitive that also works in a locale context (both for constants and
  1154 fixed variables). Type declaration and internal syntactic representation
  1155 of given constants retrieved from the context. Likewise, the
  1156 'no_notation' command allows to remove given syntax annotations from the
  1157 current context.
  1158 
  1159 * Isar/locales: new derived specification elements 'axiomatization',
  1160 'definition', 'abbreviation', which support type-inference, admit
  1161 object-level specifications (equality, equivalence).  See also the
  1162 isar-ref manual.  Examples:
  1163 
  1164   axiomatization
  1165     eq  (infix "===" 50) where
  1166     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1167 
  1168   definition "f x y = x + y + 1"
  1169   definition g where "g x = f x x"
  1170 
  1171   abbreviation
  1172     neq  (infix "=!=" 50) where
  1173     "x =!= y == ~ (x === y)"
  1174 
  1175 These specifications may be also used in a locale context.  Then the
  1176 constants being introduced depend on certain fixed parameters, and the
  1177 constant name is qualified by the locale base name.  An internal
  1178 abbreviation takes care for convenient input and output, making the
  1179 parameters implicit and using the original short name.  See also
  1180 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1181 entities from a monomorphic theory.
  1182 
  1183 Presently, abbreviations are only available 'in' a target locale, but
  1184 not inherited by general import expressions.  Also note that
  1185 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1186 'translations' in common applications.  The "no_abbrevs" print mode
  1187 prevents folding of abbreviations in term output.
  1188 
  1189 Concrete syntax is attached to specified constants in internal form,
  1190 independently of name spaces.  The parse tree representation is
  1191 slightly different -- use 'notation' instead of raw 'syntax', and
  1192 'translations' with explicit "CONST" markup to accommodate this.
  1193 
  1194 * Pure/Isar: unified syntax for new-style specification mechanisms
  1195 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1196 full type inference and dummy patterns ("_").  For example:
  1197 
  1198   definition "K x _ = x"
  1199 
  1200   inductive conj for A B
  1201   where "A ==> B ==> conj A B"
  1202 
  1203 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1204 the current context.  Print mode "no_abbrevs" prevents inversion of
  1205 abbreviations on output.
  1206 
  1207 * Isar/locales: improved parameter handling: use of locales "var" and
  1208 "struct" no longer necessary; - parameter renamings are no longer
  1209 required to be injective.  For example, this allows to define
  1210 endomorphisms as locale endom = homom mult mult h.
  1211 
  1212 * Isar/locales: changed the way locales with predicates are defined.
  1213 Instead of accumulating the specification, the imported expression is
  1214 now an interpretation.  INCOMPATIBILITY: different normal form of
  1215 locale expressions.  In particular, in interpretations of locales with
  1216 predicates, goals repesenting already interpreted fragments are not
  1217 removed automatically.  Use methods `intro_locales' and
  1218 `unfold_locales'; see below.
  1219 
  1220 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1221 provide backward reasoning on locales predicates.  The methods are
  1222 aware of interpretations and discharge corresponding goals.
  1223 `intro_locales' is less aggressive then `unfold_locales' and does not
  1224 unfold predicates to assumptions.
  1225 
  1226 * Isar/locales: the order in which locale fragments are accumulated
  1227 has changed.  This enables to override declarations from fragments due
  1228 to interpretations -- for example, unwanted simp rules.
  1229 
  1230 * Isar/locales: interpretation in theories and proof contexts has been
  1231 extended.  One may now specify (and prove) equations, which are
  1232 unfolded in interpreted theorems.  This is useful for replacing
  1233 defined concepts (constants depending on locale parameters) by
  1234 concepts already existing in the target context.  Example:
  1235 
  1236   interpretation partial_order ["op <= :: [int, int] => bool"]
  1237     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1238 
  1239 Typically, the constant `partial_order.less' is created by a
  1240 definition specification element in the context of locale
  1241 partial_order.
  1242 
  1243 * Method "induct": improved internal context management to support
  1244 local fixes and defines on-the-fly. Thus explicit meta-level
  1245 connectives !!  and ==> are rarely required anymore in inductive goals
  1246 (using object-logic connectives for this purpose has been long
  1247 obsolete anyway). Common proof patterns are explained in
  1248 src/HOL/Induct/Common_Patterns.thy, see also
  1249 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1250 examples.
  1251 
  1252 * Method "induct": improved handling of simultaneous goals. Instead of
  1253 introducing object-level conjunction, the statement is now split into
  1254 several conclusions, while the corresponding symbolic cases are nested
  1255 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1256 see src/HOL/Induct/Common_Patterns.thy, for example.
  1257 
  1258 * Method "induct": mutual induction rules are now specified as a list
  1259 of rule sharing the same induction cases. HOL packages usually provide
  1260 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1261 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1262 mutual induction rules differently, i.e. like this:
  1263 
  1264   (induct rule: foo_bar.inducts)
  1265   (induct set: foo bar)
  1266   (induct pred: foo bar)
  1267   (induct type: foo bar)
  1268 
  1269 The ML function ProjectRule.projections turns old-style rules into the
  1270 new format.
  1271 
  1272 * Method "coinduct": dual of induction, see
  1273 src/HOL/Library/Coinductive_List.thy for various examples.
  1274 
  1275 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1276 considered a legacy feature.
  1277 
  1278 * Attribute "symmetric" produces result with standardized schematic
  1279 variables (index 0).  Potential INCOMPATIBILITY.
  1280 
  1281 * Simplifier: by default the simplifier trace only shows top level
  1282 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1283 default. Thus there is less danger of being flooded by the trace. The
  1284 trace indicates where parts have been suppressed.
  1285   
  1286 * Provers/classical: removed obsolete classical version of elim_format
  1287 attribute; classical elim/dest rules are now treated uniformly when
  1288 manipulating the claset.
  1289 
  1290 * Provers/classical: stricter checks to ensure that supplied intro,
  1291 dest and elim rules are well-formed; dest and elim rules must have at
  1292 least one premise.
  1293 
  1294 * Provers/classical: attributes dest/elim/intro take an optional
  1295 weight argument for the rule (just as the Pure versions).  Weights are
  1296 ignored by automated tools, but determine the search order of single
  1297 rule steps.
  1298 
  1299 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1300 where the body does not mention the bound variable.  Note that dummy
  1301 patterns implicitly depend on their context of bounds, which makes
  1302 "{_. _}" match any set comprehension as expected.  Potential
  1303 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1304 constant "_idtdummy" in the binding position.
  1305 
  1306 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1307 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1308 for example "A -> B" => "Pi A (%_. B)".
  1309 
  1310 * Pure: 'class_deps' command visualizes the subclass relation, using
  1311 the graph browser tool.
  1312 
  1313 * Pure: 'print_theory' now suppresses certain internal declarations by
  1314 default; use '!' option for full details.
  1315 
  1316 
  1317 *** HOL ***
  1318 
  1319 * Method "metis" proves goals by applying the Metis general-purpose
  1320 resolution prover (see also http://gilith.com/software/metis/).
  1321 Examples are in the directory MetisExamples.  WARNING: the
  1322 Isabelle/HOL-Metis integration does not yet work properly with
  1323 multi-threading.
  1324   
  1325 * Command 'sledgehammer' invokes external automatic theorem provers as
  1326 background processes.  It generates calls to the "metis" method if
  1327 successful. These can be pasted into the proof.  Users do not have to
  1328 wait for the automatic provers to return.  WARNING: does not really
  1329 work with multi-threading.
  1330 
  1331 * New "auto_quickcheck" feature tests outermost goal statements for
  1332 potential counter-examples.  Controlled by ML references
  1333 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1334 5000 milliseconds).  Fails silently if statements is outside of
  1335 executable fragment, or any other codgenerator problem occurs.
  1336 
  1337 * New constant "undefined" with axiom "undefined x = undefined".
  1338 
  1339 * Added class "HOL.eq", allowing for code generation with polymorphic
  1340 equality.
  1341 
  1342 * Some renaming of class constants due to canonical name prefixing in
  1343 the new 'class' package:
  1344 
  1345     HOL.abs ~> HOL.abs_class.abs
  1346     HOL.divide ~> HOL.divide_class.divide
  1347     0 ~> HOL.zero_class.zero
  1348     1 ~> HOL.one_class.one
  1349     op + ~> HOL.plus_class.plus
  1350     op - ~> HOL.minus_class.minus
  1351     uminus ~> HOL.minus_class.uminus
  1352     op * ~> HOL.times_class.times
  1353     op < ~> HOL.ord_class.less
  1354     op <= > HOL.ord_class.less_eq
  1355     Nat.power ~> Power.power_class.power
  1356     Nat.size ~> Nat.size_class.size
  1357     Numeral.number_of ~> Numeral.number_class.number_of
  1358     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1359     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1360     Orderings.min ~> Orderings.ord_class.min
  1361     Orderings.max ~> Orderings.ord_class.max
  1362     Divides.op div ~> Divides.div_class.div
  1363     Divides.op mod ~> Divides.div_class.mod
  1364     Divides.op dvd ~> Divides.div_class.dvd
  1365 
  1366 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1367 
  1368 a) User-defined constants using any of the names "plus", "minus",
  1369 "times", "less" or "less_eq". The standard syntax translations for
  1370 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1371 names.
  1372 
  1373 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1374 INCOMPATIBILITY: use more specific names.
  1375 
  1376 c) Permutative equations (e.g. "a + b = b + a")
  1377 Since the change of names also changes the order of terms, permutative
  1378 rewrite rules may get applied in a different order. Experience shows
  1379 that this is rarely the case (only two adaptions in the whole Isabelle
  1380 distribution).  INCOMPATIBILITY: rewrite proofs
  1381 
  1382 d) ML code directly refering to constant names
  1383 This in general only affects hand-written proof tactics, simprocs and
  1384 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1385 Consider using @{const_name} antiquotation.
  1386 
  1387 * New class "default" with associated constant "default".
  1388 
  1389 * Function "sgn" is now overloaded and available on int, real, complex
  1390 (and other numeric types), using class "sgn".  Two possible defs of
  1391 sgn are given as equational assumptions in the classes sgn_if and
  1392 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1393 INCOMPATIBILITY.
  1394 
  1395 * Locale "partial_order" now unified with class "order" (cf. theory
  1396 Orderings), added parameter "less".  INCOMPATIBILITY.
  1397 
  1398 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1399 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1400 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1401 
  1402 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1403 changed order of proof goals in instance proofs.
  1404 
  1405 * The transitivity reasoner for partial and linear orders is set up
  1406 for classes "order" and "linorder".  Instances of the reasoner are available
  1407 in all contexts importing or interpreting the corresponding locales.
  1408 Method "order" invokes the reasoner separately; the reasoner
  1409 is also integrated with the Simplifier as a solver.  Diagnostic
  1410 command 'print_orders' shows the available instances of the reasoner
  1411 in the current context.
  1412 
  1413 * Localized monotonicity predicate in theory "Orderings"; integrated
  1414 lemmas max_of_mono and min_of_mono with this predicate.
  1415 INCOMPATIBILITY.
  1416 
  1417 * Formulation of theorem "dense" changed slightly due to integration
  1418 with new class dense_linear_order.
  1419 
  1420 * Uniform lattice theory development in HOL.
  1421 
  1422     constants "meet" and "join" now named "inf" and "sup"
  1423     constant "Meet" now named "Inf"
  1424 
  1425     classes "meet_semilorder" and "join_semilorder" now named
  1426       "lower_semilattice" and "upper_semilattice"
  1427     class "lorder" now named "lattice"
  1428     class "comp_lat" now named "complete_lattice"
  1429 
  1430     Instantiation of lattice classes allows explicit definitions
  1431     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1432 
  1433   INCOMPATIBILITY.  Theorem renames:
  1434 
  1435     meet_left_le            ~> inf_le1
  1436     meet_right_le           ~> inf_le2
  1437     join_left_le            ~> sup_ge1
  1438     join_right_le           ~> sup_ge2
  1439     meet_join_le            ~> inf_sup_ord
  1440     le_meetI                ~> le_infI
  1441     join_leI                ~> le_supI
  1442     le_meet                 ~> le_inf_iff
  1443     le_join                 ~> ge_sup_conv
  1444     meet_idempotent         ~> inf_idem
  1445     join_idempotent         ~> sup_idem
  1446     meet_comm               ~> inf_commute
  1447     join_comm               ~> sup_commute
  1448     meet_leI1               ~> le_infI1
  1449     meet_leI2               ~> le_infI2
  1450     le_joinI1               ~> le_supI1
  1451     le_joinI2               ~> le_supI2
  1452     meet_assoc              ~> inf_assoc
  1453     join_assoc              ~> sup_assoc
  1454     meet_left_comm          ~> inf_left_commute
  1455     meet_left_idempotent    ~> inf_left_idem
  1456     join_left_comm          ~> sup_left_commute
  1457     join_left_idempotent    ~> sup_left_idem
  1458     meet_aci                ~> inf_aci
  1459     join_aci                ~> sup_aci
  1460     le_def_meet             ~> le_iff_inf
  1461     le_def_join             ~> le_iff_sup
  1462     join_absorp2            ~> sup_absorb2
  1463     join_absorp1            ~> sup_absorb1
  1464     meet_absorp1            ~> inf_absorb1
  1465     meet_absorp2            ~> inf_absorb2
  1466     meet_join_absorp        ~> inf_sup_absorb
  1467     join_meet_absorp        ~> sup_inf_absorb
  1468     distrib_join_le         ~> distrib_sup_le
  1469     distrib_meet_le         ~> distrib_inf_le
  1470 
  1471     add_meet_distrib_left   ~> add_inf_distrib_left
  1472     add_join_distrib_left   ~> add_sup_distrib_left
  1473     is_join_neg_meet        ~> is_join_neg_inf
  1474     is_meet_neg_join        ~> is_meet_neg_sup
  1475     add_meet_distrib_right  ~> add_inf_distrib_right
  1476     add_join_distrib_right  ~> add_sup_distrib_right
  1477     add_meet_join_distribs  ~> add_sup_inf_distribs
  1478     join_eq_neg_meet        ~> sup_eq_neg_inf
  1479     meet_eq_neg_join        ~> inf_eq_neg_sup
  1480     add_eq_meet_join        ~> add_eq_inf_sup
  1481     meet_0_imp_0            ~> inf_0_imp_0
  1482     join_0_imp_0            ~> sup_0_imp_0
  1483     meet_0_eq_0             ~> inf_0_eq_0
  1484     join_0_eq_0             ~> sup_0_eq_0
  1485     neg_meet_eq_join        ~> neg_inf_eq_sup
  1486     neg_join_eq_meet        ~> neg_sup_eq_inf
  1487     join_eq_if              ~> sup_eq_if
  1488 
  1489     mono_meet               ~> mono_inf
  1490     mono_join               ~> mono_sup
  1491     meet_bool_eq            ~> inf_bool_eq
  1492     join_bool_eq            ~> sup_bool_eq
  1493     meet_fun_eq             ~> inf_fun_eq
  1494     join_fun_eq             ~> sup_fun_eq
  1495     meet_set_eq             ~> inf_set_eq
  1496     join_set_eq             ~> sup_set_eq
  1497     meet1_iff               ~> inf1_iff
  1498     meet2_iff               ~> inf2_iff
  1499     meet1I                  ~> inf1I
  1500     meet2I                  ~> inf2I
  1501     meet1D1                 ~> inf1D1
  1502     meet2D1                 ~> inf2D1
  1503     meet1D2                 ~> inf1D2
  1504     meet2D2                 ~> inf2D2
  1505     meet1E                  ~> inf1E
  1506     meet2E                  ~> inf2E
  1507     join1_iff               ~> sup1_iff
  1508     join2_iff               ~> sup2_iff
  1509     join1I1                 ~> sup1I1
  1510     join2I1                 ~> sup2I1
  1511     join1I1                 ~> sup1I1
  1512     join2I2                 ~> sup1I2
  1513     join1CI                 ~> sup1CI
  1514     join2CI                 ~> sup2CI
  1515     join1E                  ~> sup1E
  1516     join2E                  ~> sup2E
  1517 
  1518     is_meet_Meet            ~> is_meet_Inf
  1519     Meet_bool_def           ~> Inf_bool_def
  1520     Meet_fun_def            ~> Inf_fun_def
  1521     Meet_greatest           ~> Inf_greatest
  1522     Meet_lower              ~> Inf_lower
  1523     Meet_set_def            ~> Inf_set_def
  1524 
  1525     Sup_def                 ~> Sup_Inf
  1526     Sup_bool_eq             ~> Sup_bool_def
  1527     Sup_fun_eq              ~> Sup_fun_def
  1528     Sup_set_eq              ~> Sup_set_def
  1529 
  1530     listsp_meetI            ~> listsp_infI
  1531     listsp_meet_eq          ~> listsp_inf_eq
  1532 
  1533     meet_min                ~> inf_min
  1534     join_max                ~> sup_max
  1535 
  1536 * Added syntactic class "size"; overloaded constant "size" now has
  1537 type "'a::size ==> bool"
  1538 
  1539 * Internal reorganisation of `size' of datatypes: size theorems
  1540 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1541 simplification rules by default!); theorems "prod.size" now named
  1542 "*.size".
  1543 
  1544 * Class "div" now inherits from class "times" rather than "type".
  1545 INCOMPATIBILITY.
  1546 
  1547 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1548 Linorder etc.  have disappeared; operations defined in terms of
  1549 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1550 
  1551 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1552 
  1553 * HOL-Word: New extensive library and type for generic, fixed size
  1554 machine words, with arithemtic, bit-wise, shifting and rotating
  1555 operations, reflection into int, nat, and bool lists, automation for
  1556 linear arithmetic (by automatic reflection into nat or int), including
  1557 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1558 arithmetic type classes, supporting automatic simplification of
  1559 numerals on all operations.
  1560 
  1561 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1562 
  1563 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1564 
  1565 * Code generator library theories:
  1566   - Code_Integer represents HOL integers by big integer literals in target
  1567     languages.
  1568   - Code_Char represents HOL characters by character literals in target
  1569     languages.
  1570   - Code_Char_chr like Code_Char, but also offers treatment of character
  1571     codes; includes Code_Integer.
  1572   - Executable_Set allows to generate code for finite sets using lists.
  1573   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1574     denominator).
  1575   - Executable_Real implements a subset of real numbers, namly those
  1576     representable by rational numbers.
  1577   - Efficient_Nat implements natural numbers by integers, which in general will
  1578     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1579     includes Code_Integer.
  1580   - Code_Index provides an additional datatype index which is mapped to
  1581     target-language built-in integers.
  1582   - Code_Message provides an additional datatype message_string which is isomorphic to
  1583     strings; messages are mapped to target-language strings.
  1584 
  1585 * New package for inductive predicates
  1586 
  1587   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1588 
  1589     inductive
  1590       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1591       for z_1 :: U_1 and ... and z_n :: U_m
  1592     where
  1593       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1594     | ...
  1595 
  1596   with full support for type-inference, rather than
  1597 
  1598     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1599 
  1600     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1601     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1602 
  1603     inductive "s z_1 ... z_m"
  1604     intros
  1605       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1606       ...
  1607 
  1608   For backward compatibility, there is a wrapper allowing inductive
  1609   sets to be defined with the new package via
  1610 
  1611     inductive_set
  1612       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1613       for z_1 :: U_1 and ... and z_n :: U_m
  1614     where
  1615       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1616     | ...
  1617 
  1618   or
  1619 
  1620     inductive_set
  1621       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1622       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1623       for z_1 :: U_1 and ... and z_n :: U_m
  1624     where
  1625       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1626     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1627     | ...
  1628 
  1629   if the additional syntax "p ..." is required.
  1630 
  1631   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1632   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1633 
  1634   INCOMPATIBILITIES:
  1635 
  1636   - Since declaration and definition of inductive sets or predicates
  1637     is no longer separated, abbreviations involving the newly
  1638     introduced sets or predicates must be specified together with the
  1639     introduction rules after the 'where' keyword (see above), rather
  1640     than before the actual inductive definition.
  1641 
  1642   - The variables in induction and elimination rules are now
  1643     quantified in the order of their occurrence in the introduction
  1644     rules, rather than in alphabetical order. Since this may break
  1645     some proofs, these proofs either have to be repaired, e.g. by
  1646     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1647     statements of the form
  1648 
  1649       case (rule_i a_i_1 ... a_i_{k_i})
  1650 
  1651     or the old order of quantification has to be restored by explicitly adding
  1652     meta-level quantifiers in the introduction rules, i.e.
  1653 
  1654       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1655 
  1656   - The format of the elimination rules is now
  1657 
  1658       p z_1 ... z_m x_1 ... x_n ==>
  1659         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1660         ==> ... ==> P
  1661 
  1662     for predicates and
  1663 
  1664       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1665         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1666         ==> ... ==> P
  1667 
  1668     for sets rather than
  1669 
  1670       x : s z_1 ... z_m ==>
  1671         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1672         ==> ... ==> P
  1673 
  1674     This may require terms in goals to be expanded to n-tuples
  1675     (e.g. using case_tac or simplification with the split_paired_all
  1676     rule) before the above elimination rule is applicable.
  1677 
  1678   - The elimination or case analysis rules for (mutually) inductive
  1679     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1680     list of rules "p_1_..._p_k.elims" is no longer available.
  1681 
  1682 * New package "function"/"fun" for general recursive functions,
  1683 supporting mutual and nested recursion, definitions in local contexts,
  1684 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1685 for small examples, and the separate tutorial on the function
  1686 package. The old recdef "package" is still available as before, but
  1687 users are encouraged to use the new package.
  1688 
  1689 * Method "lexicographic_order" automatically synthesizes termination
  1690 relations as lexicographic combinations of size measures. 
  1691 
  1692 * Case-expressions allow arbitrary constructor-patterns (including
  1693 "_") and take their order into account, like in functional
  1694 programming.  Internally, this is translated into nested
  1695 case-expressions; missing cases are added and mapped to the predefined
  1696 constant "undefined". In complicated cases printing may no longer show
  1697 the original input but the internal form. Lambda-abstractions allow
  1698 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1699 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1700 variable.
  1701 
  1702 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1703 is an abbreviation for "of_nat :: nat => int". The simplification
  1704 rules for "of_nat" have been changed to work like "int" did
  1705 previously.  Potential INCOMPATIBILITY:
  1706   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1707   - of_nat_diff and of_nat_mult are no longer default simp rules
  1708 
  1709 * Method "algebra" solves polynomial equations over (semi)rings using
  1710 Groebner bases. The (semi)ring structure is defined by locales and the
  1711 tool setup depends on that generic context. Installing the method for
  1712 a specific type involves instantiating the locale and possibly adding
  1713 declarations for computation on the coefficients.  The method is
  1714 already instantiated for natural numbers and for the axiomatic class
  1715 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1716 CALCULEMUS 2007 for the general principles underlying this
  1717 architecture of context-aware proof-tools.
  1718 
  1719 * Method "ferrack" implements quantifier elimination over
  1720 special-purpose dense linear orders using locales (analogous to
  1721 "algebra"). The method is already installed for class
  1722 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1723 rat, etc.
  1724 
  1725 * Former constant "List.op @" now named "List.append".  Use ML
  1726 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1727 circumvent possible incompatibilities when working on ML level.
  1728 
  1729 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1730 
  1731 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1732 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1733 
  1734 * New syntax for Haskell-like list comprehension (input only), eg.
  1735 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1736 
  1737 * The special syntax for function "filter" has changed from [x :
  1738 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1739 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1740 
  1741 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1742 defined on nat only, as an abbreviation for [a..<Suc b]
  1743 INCOMPATIBILITY.
  1744 
  1745 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1746 
  1747 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1748 
  1749 * New lemma collection field_simps (an extension of ring_simps) for
  1750 manipulating (in)equations involving division. Multiplies with all
  1751 denominators that can be proved to be non-zero (in equations) or
  1752 positive/negative (in inequations).
  1753 
  1754 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1755 have been improved and renamed to ring_simps, group_simps and
  1756 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1757 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1758 
  1759 * Theory Library/Commutative_Ring: switched from recdef to function
  1760 package; constants add, mul, pow now curried.  Infix syntax for
  1761 algebraic operations.
  1762 
  1763 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1764 INCOMPATIBILITY.
  1765 
  1766 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1767 INCOMPATIBILITY.
  1768 
  1769 * HOL/records: generalised field-update to take a function on the
  1770 field rather than the new value: r(|A := x|) is translated to A_update
  1771 (K x) r The K-combinator that is internally used is called K_record.
  1772 INCOMPATIBILITY: Usage of the plain update functions has to be
  1773 adapted.
  1774  
  1775 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1776 * x = 0, which are required for a semiring.  Richer structures do not
  1777 inherit from semiring_0 anymore, because this property is a theorem
  1778 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1779 there is more to prove, but this is mostly trivial.
  1780 
  1781 * Class "recpower" is generalized to arbitrary monoids, not just
  1782 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1783 commutativity or semiring properties additionally.
  1784 
  1785 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1786 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1787 better use 'abbreviation'.
  1788 
  1789 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1790 
  1791 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1792 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1793 significant changes for setting up numeral syntax for types:
  1794   - New constants Numeral.pred and Numeral.succ instead
  1795       of former Numeral.bin_pred and Numeral.bin_succ.
  1796   - Use integer operations instead of bin_add, bin_mult and so on.
  1797   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1798   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1799 
  1800 See src/HOL/Integ/IntArith.thy for an example setup.
  1801 
  1802 * Command 'normal_form' computes the normal form of a term that may
  1803 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1804 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1805 heavy-duty computations because the functions are compiled to ML
  1806 first.  Correspondingly, a method "normalization" is provided.  See
  1807 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1808 
  1809 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1810 25 like -->); output depends on the "iff" print_mode, the default is
  1811 "A = B" (with priority 50).
  1812 
  1813 * Relations less (<) and less_eq (<=) are also available on type bool.
  1814 Modified syntax to disallow nesting without explicit parentheses,
  1815 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1816 INCOMPATIBILITY.
  1817 
  1818 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1819 
  1820 * Relation composition operator "op O" now has precedence 75 and binds
  1821 stronger than union and intersection. INCOMPATIBILITY.
  1822 
  1823 * The old set interval syntax "{m..n(}" (and relatives) has been
  1824 removed.  Use "{m..<n}" (and relatives) instead.
  1825 
  1826 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1827 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1828 ``declare [[simproc del: neq]]''.
  1829 
  1830 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1831 True/False.
  1832 
  1833 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1834 
  1835 * Theorem setsum_mult renamed to setsum_right_distrib.
  1836 
  1837 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1838 ``rule'' method.
  1839 
  1840 * Reimplemented methods "sat" and "satx", with several improvements:
  1841 goals no longer need to be stated as "<prems> ==> False", equivalences
  1842 (i.e. "=" on type bool) are handled, variable names of the form
  1843 "lit_<n>" are no longer reserved, significant speedup.
  1844 
  1845 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1846 zChaff is still supported as well.
  1847 
  1848 * 'inductive' and 'datatype': provide projections of mutual rules,
  1849 bundled as foo_bar.inducts;
  1850 
  1851 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1852 Library.
  1853 
  1854 * Library: moved theory Accessible_Part to main HOL.
  1855 
  1856 * Library: added theory Coinductive_List of potentially infinite lists
  1857 as greatest fixed-point.
  1858 
  1859 * Library: added theory AssocList which implements (finite) maps as
  1860 association lists.
  1861 
  1862 * Method "evaluation" solves goals (i.e. a boolean expression)
  1863 efficiently by compiling it to ML.  The goal is "proved" (via an
  1864 oracle) if it evaluates to True.
  1865 
  1866 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1867 also when invoked by the simplifier.  This results in the Simplifier
  1868 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1869 Configuration option fast_arith_split_limit=0 recovers the old
  1870 behavior.
  1871 
  1872 * Support for hex (0x20) and binary (0b1001) numerals.
  1873 
  1874 * New method: reify eqs (t), where eqs are equations for an
  1875 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1876 parameter, computes a term s::'b and a list xs::'a list and proves the
  1877 theorem I xs s = t. This is also known as reification or quoting. The
  1878 resulting theorem is applied to the subgoal to substitute t with I xs
  1879 s.  If t is omitted, the subgoal itself is reified.
  1880 
  1881 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1882 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1883 where f is supposed to be a computable function (in the sense of code
  1884 generattion). The method uses reify to compute s and xs as above then
  1885 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1886 r and finally gets the theorem t = r, which is again applied to the
  1887 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1888 
  1889 * Reflection: Automatic reification now handels binding, an example is
  1890 available in src/HOL/ex/ReflectionEx.thy
  1891 
  1892 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1893 command 'statespace' that is similar to 'record', but introduces an
  1894 abstract specification based on the locale infrastructure instead of
  1895 HOL types.  This leads to extra flexibility in composing state spaces,
  1896 in particular multiple inheritance and renaming of components.
  1897 
  1898 
  1899 *** HOL-Complex ***
  1900 
  1901 * Hyperreal: Functions root and sqrt are now defined on negative real
  1902 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1903 Nonnegativity side conditions have been removed from many lemmas, so
  1904 that more subgoals may now be solved by simplification; potential
  1905 INCOMPATIBILITY.
  1906 
  1907 * Real: new type classes formalize real normed vector spaces and
  1908 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1909 and norm :: 'a => real.
  1910 
  1911 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1912 reals into other types. The overloaded constant Reals :: 'a set is now
  1913 defined as range of_real; potential INCOMPATIBILITY.
  1914 
  1915 * Real: proper support for ML code generation, including 'quickcheck'.
  1916 Reals are implemented as arbitrary precision rationals.
  1917 
  1918 * Hyperreal: Several constants that previously worked only for the
  1919 reals have been generalized, so they now work over arbitrary vector
  1920 spaces. Type annotations may need to be added in some cases; potential
  1921 INCOMPATIBILITY.
  1922 
  1923   Infinitesimal  :: ('a::real_normed_vector) star set
  1924   HFinite        :: ('a::real_normed_vector) star set
  1925   HInfinite      :: ('a::real_normed_vector) star set
  1926   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1927   monad          :: ('a::real_normed_vector) star => 'a star set
  1928   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1929   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1930   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1931   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1932   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1933   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1934   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1935   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1936   sgn            :: 'a::real_normed_vector => 'a
  1937   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1938 
  1939 * Complex: Some complex-specific constants are now abbreviations for
  1940 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1941 hnorm.  Other constants have been entirely removed in favor of the
  1942 polymorphic versions (INCOMPATIBILITY):
  1943 
  1944   approx        <-- capprox
  1945   HFinite       <-- CFinite
  1946   HInfinite     <-- CInfinite
  1947   Infinitesimal <-- CInfinitesimal
  1948   monad         <-- cmonad
  1949   galaxy        <-- cgalaxy
  1950   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1951   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1952   (ns)deriv     <-- (ns)cderiv
  1953 
  1954 
  1955 *** HOL-Algebra ***
  1956 
  1957 * Formalisation of ideals and the quotient construction over rings.
  1958 
  1959 * Order and lattice theory no longer based on records.
  1960 INCOMPATIBILITY.
  1961 
  1962 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1963 greatest_closed.  INCOMPATIBILITY.
  1964 
  1965 * Method algebra is now set up via an attribute.  For examples see
  1966 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1967 of algebraic structures.
  1968 
  1969 * Renamed theory CRing to Ring.
  1970 
  1971 
  1972 *** HOL-Nominal ***
  1973 
  1974 * Substantial, yet incomplete support for nominal datatypes (binding
  1975 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1976 src/HOL/Nominal/Examples.  Prospective users should consult
  1977 http://isabelle.in.tum.de/nominal/
  1978 
  1979 
  1980 *** ML ***
  1981 
  1982 * ML basics: just one true type int, which coincides with IntInf.int
  1983 (even on SML/NJ).
  1984 
  1985 * ML within Isar: antiquotations allow to embed statically-checked
  1986 formal entities in the source, referring to the context available at
  1987 compile-time.  For example:
  1988 
  1989 ML {* @{sort "{zero,one}"} *}
  1990 ML {* @{typ "'a => 'b"} *}
  1991 ML {* @{term "%x. x"} *}
  1992 ML {* @{prop "x == y"} *}
  1993 ML {* @{ctyp "'a => 'b"} *}
  1994 ML {* @{cterm "%x. x"} *}
  1995 ML {* @{cprop "x == y"} *}
  1996 ML {* @{thm asm_rl} *}
  1997 ML {* @{thms asm_rl} *}
  1998 ML {* @{type_name c} *}
  1999 ML {* @{type_syntax c} *}
  2000 ML {* @{const_name c} *}
  2001 ML {* @{const_syntax c} *}
  2002 ML {* @{context} *}
  2003 ML {* @{theory} *}
  2004 ML {* @{theory Pure} *}
  2005 ML {* @{theory_ref} *}
  2006 ML {* @{theory_ref Pure} *}
  2007 ML {* @{simpset} *}
  2008 ML {* @{claset} *}
  2009 ML {* @{clasimpset} *}
  2010 
  2011 The same works for sources being ``used'' within an Isar context.
  2012 
  2013 * ML in Isar: improved error reporting; extra verbosity with
  2014 ML_Context.trace enabled.
  2015 
  2016 * Pure/General/table.ML: the join operations now works via exceptions
  2017 DUP/SAME instead of type option. This is simpler in simple cases, and
  2018 admits slightly more efficient complex applications.
  2019 
  2020 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2021 use Context.generic instead of just theory.
  2022 
  2023 * Pure: datatype Context.generic joins theory/Proof.context and
  2024 provides some facilities for code that works in either kind of
  2025 context, notably GenericDataFun for uniform theory and proof data.
  2026 
  2027 * Pure: simplified internal attribute type, which is now always
  2028 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2029 local (Proof.context) attributes have been discontinued, while
  2030 minimizing code duplication. Thm.rule_attribute and
  2031 Thm.declaration_attribute build canonical attributes; see also structure
  2032 Context for further operations on Context.generic, notably
  2033 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2034 declarations and definitions.
  2035 
  2036 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2037 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2038 init only required for impure data. INCOMPATIBILITY: empty really need
  2039 to be empty (no dependencies on theory content!)
  2040 
  2041 * Pure/kernel: consts certification ignores sort constraints given in
  2042 signature declarations. (This information is not relevant to the
  2043 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2044 potential INCOMPATIBILITY.
  2045 
  2046 * Pure: axiomatic type classes are now purely definitional, with
  2047 explicit proofs of class axioms and super class relations performed
  2048 internally. See Pure/axclass.ML for the main internal interfaces --
  2049 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2050 AxClass.axiomatize_class/classrel/arity supersede
  2051 Sign.add_classes/classrel/arities.
  2052 
  2053 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2054 global/local versions on theory vs. Proof.context have been
  2055 discontinued; Attrib.syntax and Method.syntax have been adapted
  2056 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2057 attributes, methods, etc.
  2058 
  2059 * Pure: several functions of signature "... -> theory -> theory * ..."
  2060 have been reoriented to "... -> theory -> ... * theory" in order to
  2061 allow natural usage in combination with the ||>, ||>>, |-> and
  2062 fold_map combinators.
  2063 
  2064 * Pure: official theorem names (closed derivations) and additional
  2065 comments (tags) are now strictly separate.  Name hints -- which are
  2066 maintained as tags -- may be attached any time without affecting the
  2067 derivation.
  2068 
  2069 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2070 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2071 achieve the old behaviour.
  2072 
  2073 * Pure: the "Goal" constant is now called "prop", supporting a
  2074 slightly more general idea of ``protecting'' meta-level rule
  2075 statements.
  2076 
  2077 * Pure: Logic.(un)varify only works in a global context, which is now
  2078 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2079 Logic.legacy_(un)varify as temporary workaround.
  2080 
  2081 * Pure: structure Name provides scalable operations for generating
  2082 internal variable names, notably Name.variants etc.  This replaces
  2083 some popular functions from term.ML:
  2084 
  2085   Term.variant		->  Name.variant
  2086   Term.variantlist	->  Name.variant_list
  2087   Term.invent_names	->  Name.invent_list
  2088 
  2089 Note that low-level renaming rarely occurs in new code -- operations
  2090 from structure Variable are used instead (see below).
  2091 
  2092 * Pure: structure Variable provides fundamental operations for proper
  2093 treatment of fixed/schematic variables in a context.  For example,
  2094 Variable.import introduces fixes for schematics of given facts and
  2095 Variable.export reverses the effect (up to renaming) -- this replaces
  2096 various freeze_thaw operations.
  2097 
  2098 * Pure: structure Goal provides simple interfaces for
  2099 init/conclude/finish and tactical prove operations (replacing former
  2100 Tactic.prove).  Goal.prove is the canonical way to prove results
  2101 within a given context; Goal.prove_global is a degraded version for
  2102 theory level goals, including a global Drule.standard.  Note that
  2103 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2104 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2105 in a locale context).
  2106 
  2107 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2108 and type checking (Syntax.check_term etc.), with common combinations
  2109 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2110 which are considered legacy and await removal.
  2111 
  2112 * Pure/Syntax: generic interfaces for type unchecking
  2113 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2114 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2115 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2116 available for convenience, but refer to the very same operations using
  2117 a mere theory instead of a full context.
  2118 
  2119 * Isar: simplified treatment of user-level errors, using exception
  2120 ERROR of string uniformly.  Function error now merely raises ERROR,
  2121 without any side effect on output channels.  The Isar toplevel takes
  2122 care of proper display of ERROR exceptions.  ML code may use plain
  2123 handle/can/try; cat_error may be used to concatenate errors like this:
  2124 
  2125   ... handle ERROR msg => cat_error msg "..."
  2126 
  2127 Toplevel ML code (run directly or through the Isar toplevel) may be
  2128 embedded into the Isar toplevel with exception display/debug like
  2129 this:
  2130 
  2131   Isar.toplevel (fn () => ...)
  2132 
  2133 INCOMPATIBILITY, removed special transform_error facilities, removed
  2134 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2135 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2136 -- use plain ERROR instead.
  2137 
  2138 * Isar: theory setup now has type (theory -> theory), instead of a
  2139 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2140 
  2141 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2142 ProofContext.debug/verbose flags.
  2143 
  2144 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2145 theory before entering a proof state.  Transactions now always see a
  2146 quasi-functional intermediate checkpoint, both in interactive and
  2147 batch mode.
  2148 
  2149 * Isar: simplified interfaces for outer syntax.  Renamed
  2150 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2151 OuterSyntax.add_parsers -- this functionality is now included in
  2152 OuterSyntax.command etc.  INCOMPATIBILITY.
  2153 
  2154 * Simplifier: the simpset of a running simplification process now
  2155 contains a proof context (cf. Simplifier.the_context), which is the
  2156 very context that the initial simpset has been retrieved from (by
  2157 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2158 (solver, looper etc.) may depend on arbitrary proof data.
  2159 
  2160 * Simplifier.inherit_context inherits the proof context (plus the
  2161 local bounds) of the current simplification process; any simproc
  2162 etc. that calls the Simplifier recursively should do this!  Removed
  2163 former Simplifier.inherit_bounds, which is already included here --
  2164 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2165 specify an explicit context using Simplifier.context/theory_context.
  2166 
  2167 * Simplifier/Classical Reasoner: more abstract interfaces
  2168 change_simpset/claset for modifying the simpset/claset reference of a
  2169 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2170 INCOMPATIBILITY.
  2171 
  2172 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2173 "Trueprop" etc.
  2174 
  2175 
  2176 *** System ***
  2177 
  2178 * settings: the default heap location within ISABELLE_HOME_USER now
  2179 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2180 Isabelle installations.
  2181 
  2182 * isabelle-process: option -S (secure mode) disables some critical
  2183 operations, notably runtime compilation and evaluation of ML source
  2184 code.
  2185 
  2186 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2187 
  2188 * Support for parallel execution, using native multicore support of
  2189 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2190 independent theories, according to the given theory header
  2191 specifications. The maximum number of worker threads is specified via
  2192 usedir option -M or the "max-threads" setting in Proof General. A
  2193 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2194 to 6 on a 8-core machine.  User-code needs to observe certain
  2195 guidelines for thread-safe programming, see appendix A in the Isar
  2196 Implementation manual.
  2197 
  2198 
  2199 
  2200 New in Isabelle2005 (October 2005)
  2201 ----------------------------------
  2202 
  2203 *** General ***
  2204 
  2205 * Theory headers: the new header syntax for Isar theories is
  2206 
  2207   theory <name>
  2208   imports <theory1> ... <theoryN>
  2209   uses <file1> ... <fileM>
  2210   begin
  2211 
  2212 where the 'uses' part is optional.  The previous syntax
  2213 
  2214   theory <name> = <theory1> + ... + <theoryN>:
  2215 
  2216 will disappear in the next release.  Use isatool fixheaders to convert
  2217 existing theory files.  Note that there is no change in ancient
  2218 non-Isar theories now, but these will disappear soon.
  2219 
  2220 * Theory loader: parent theories can now also be referred to via
  2221 relative and absolute paths.
  2222 
  2223 * Command 'find_theorems' searches for a list of criteria instead of a
  2224 list of constants. Known criteria are: intro, elim, dest, name:string,
  2225 simp:term, and any term. Criteria can be preceded by '-' to select
  2226 theorems that do not match. Intro, elim, dest select theorems that
  2227 match the current goal, name:s selects theorems whose fully qualified
  2228 name contain s, and simp:term selects all simplification rules whose
  2229 lhs match term.  Any other term is interpreted as pattern and selects
  2230 all theorems matching the pattern. Available in ProofGeneral under
  2231 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2232 
  2233   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2234 
  2235 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2236 matching the current goal as introduction rule and not having "HOL."
  2237 in their name (i.e. not being defined in theory HOL).
  2238 
  2239 * Command 'thms_containing' has been discontinued in favour of
  2240 'find_theorems'; INCOMPATIBILITY.
  2241 
  2242 * Communication with Proof General is now 8bit clean, which means that
  2243 Unicode text in UTF-8 encoding may be used within theory texts (both
  2244 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2245 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2246 
  2247   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2248   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2249 
  2250 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2251 Classical Reasoner.  Typical big applications run around 2 times
  2252 faster.
  2253 
  2254 
  2255 *** Document preparation ***
  2256 
  2257 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2258 of raw sources.  Only those symbols that do not require additional
  2259 LaTeX packages (depending on comments in isabellesym.sty) are
  2260 displayed properly, everything else is left verbatim.  isatool display
  2261 and isatool print are used as front ends (these are subject to the
  2262 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2263 
  2264 * Command tags control specific markup of certain regions of text,
  2265 notably folding and hiding.  Predefined tags include "theory" (for
  2266 theory begin and end), "proof" for proof commands, and "ML" for
  2267 commands involving ML code; the additional tags "visible" and
  2268 "invisible" are unused by default.  Users may give explicit tag
  2269 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2270 interpretation of tags is determined by the LaTeX job during document
  2271 preparation: see option -V of isatool usedir, or options -n and -t of
  2272 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2273 \isadroptag.
  2274 
  2275 Several document versions may be produced at the same time via isatool
  2276 usedir (the generated index.html will link all of them).  Typical
  2277 specifications include ''-V document=theory,proof,ML'' to present
  2278 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2279 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2280 these parts without any formal replacement text.  The Isabelle site
  2281 default settings produce ''document'' and ''outline'' versions as
  2282 specified above.
  2283 
  2284 * Several new antiquotations:
  2285 
  2286   @{term_type term} prints a term with its type annotated;
  2287 
  2288   @{typeof term} prints the type of a term;
  2289 
  2290   @{const const} is the same as @{term const}, but checks that the
  2291   argument is a known logical constant;
  2292 
  2293   @{term_style style term} and @{thm_style style thm} print a term or
  2294   theorem applying a "style" to it
  2295 
  2296   @{ML text}
  2297 
  2298 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2299 definitions, equations, inequations etc., 'concl' printing only the
  2300 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2301 to print the specified premise.  TermStyle.add_style provides an ML
  2302 interface for introducing further styles.  See also the "LaTeX Sugar"
  2303 document practical applications.  The ML antiquotation prints
  2304 type-checked ML expressions verbatim.
  2305 
  2306 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2307 and 'text' support optional locale specification '(in loc)', which
  2308 specifies the default context for interpreting antiquotations.  For
  2309 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2310 
  2311 * Option 'locale=NAME' of antiquotations specifies an alternative
  2312 context interpreting the subsequent argument.  For example: @{thm
  2313 [locale=lattice] inf_assoc}.
  2314 
  2315 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2316 a proof context.
  2317 
  2318 * Proper output of antiquotations for theory commands involving a
  2319 proof context (such as 'locale' or 'theorem (in loc) ...').
  2320 
  2321 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2322 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2323 
  2324 * isatool usedir: new option -C (default true) controls whether option
  2325 -D should include a copy of the original document directory; -C false
  2326 prevents unwanted effects such as copying of administrative CVS data.
  2327 
  2328 
  2329 *** Pure ***
  2330 
  2331 * Considerably improved version of 'constdefs' command.  Now performs
  2332 automatic type-inference of declared constants; additional support for
  2333 local structure declarations (cf. locales and HOL records), see also
  2334 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2335 sequential dependencies of definitions within a single 'constdefs'
  2336 section; moreover, the declared name needs to be an identifier.  If
  2337 all fails, consider to fall back on 'consts' and 'defs' separately.
  2338 
  2339 * Improved indexed syntax and implicit structures.  First of all,
  2340 indexed syntax provides a notational device for subscripted
  2341 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2342 expressions.  Secondly, in a local context with structure
  2343 declarations, number indexes \<^sub>n or the empty index (default
  2344 number 1) refer to a certain fixed variable implicitly; option
  2345 show_structs controls printing of implicit structures.  Typical
  2346 applications of these concepts involve record types and locales.
  2347 
  2348 * New command 'no_syntax' removes grammar declarations (and
  2349 translations) resulting from the given syntax specification, which is
  2350 interpreted in the same manner as for the 'syntax' command.
  2351 
  2352 * 'Advanced' translation functions (parse_translation etc.) may depend
  2353 on the signature of the theory context being presently used for
  2354 parsing/printing, see also isar-ref manual.
  2355 
  2356 * Improved 'oracle' command provides a type-safe interface to turn an
  2357 ML expression of type theory -> T -> term into a primitive rule of
  2358 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2359 is already included here); see also FOL/ex/IffExample.thy;
  2360 INCOMPATIBILITY.
  2361 
  2362 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2363 before); "cI" is no longer bound, use "c.intro" instead.
  2364 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2365 axclasses vs. locales.
  2366 
  2367 * Improved internal renaming of symbolic identifiers -- attach primes
  2368 instead of base 26 numbers.
  2369 
  2370 * New flag show_question_marks controls printing of leading question
  2371 marks in schematic variable names.
  2372 
  2373 * In schematic variable names, *any* symbol following \<^isub> or
  2374 \<^isup> is now treated as part of the base name.  For example, the
  2375 following works without printing of awkward ".0" indexes:
  2376 
  2377   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2378     by simp
  2379 
  2380 * Inner syntax includes (*(*nested*) comments*).
  2381 
  2382 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2383 annotations as "(00...)".
  2384 
  2385 * Clear separation of logical types and nonterminals, where the latter
  2386 may only occur in 'syntax' specifications or type abbreviations.
  2387 Before that distinction was only partially implemented via type class
  2388 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2389 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2390 exotic syntax specifications may require further adaption
  2391 (e.g. Cube/Cube.thy).
  2392 
  2393 * Removed obsolete type class "logic", use the top sort {} instead.
  2394 Note that non-logical types should be declared as 'nonterminals'
  2395 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2396 specifications.
  2397 
  2398 * Attributes 'induct' and 'cases': type or set names may now be
  2399 locally fixed variables as well.
  2400 
  2401 * Simplifier: can now control the depth to which conditional rewriting
  2402 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2403 Limit.
  2404 
  2405 * Simplifier: simplification procedures may now take the current
  2406 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2407 interface), which is very useful for calling the Simplifier
  2408 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2409 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2410 low-level mk_simproc no longer applies Logic.varify internally, to
  2411 allow for use in a context of fixed variables.
  2412 
  2413 * thin_tac now works even if the assumption being deleted contains !!
  2414 or ==>.  More generally, erule now works even if the major premise of
  2415 the elimination rule contains !! or ==>.
  2416 
  2417 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2418 
  2419 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2420 from Pure, which contains all common declarations already.  Both
  2421 theories are defined via plain Isabelle/Isar .thy files.
  2422 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2423 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2424 use isatool fixcpure to adapt your theory and ML sources.
  2425 
  2426 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2427 selections of theorems in named facts via index ranges.
  2428 
  2429 * 'print_theorems': in theory mode, really print the difference
  2430 wrt. the last state (works for interactive theory development only),
  2431 in proof mode print all local facts (cf. 'print_facts');
  2432 
  2433 * 'hide': option '(open)' hides only base names.
  2434 
  2435 * More efficient treatment of intermediate checkpoints in interactive
  2436 theory development.
  2437 
  2438 * Code generator is now invoked via code_module (incremental code
  2439 generation) and code_library (modular code generation, ML structures
  2440 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2441 must be quoted when used as identifiers.
  2442 
  2443 * New 'value' command for reading, evaluating and printing terms using
  2444 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2445 quoted when used as identifier.
  2446 
  2447 
  2448 *** Locales ***
  2449 
  2450 * New commands for the interpretation of locale expressions in
  2451 theories (1), locales (2) and proof contexts (3).  These generate
  2452 proof obligations from the expression specification.  After the
  2453 obligations have been discharged, theorems of the expression are added
  2454 to the theory, target locale or proof context.  The synopsis of the
  2455 commands is a follows:
  2456 
  2457   (1) interpretation expr inst
  2458   (2) interpretation target < expr
  2459   (3) interpret expr inst
  2460 
  2461 Interpretation in theories and proof contexts require a parameter
  2462 instantiation of terms from the current context.  This is applied to
  2463 specifications and theorems of the interpreted expression.
  2464 Interpretation in locales only permits parameter renaming through the
  2465 locale expression.  Interpretation is smart in that interpretations
  2466 that are active already do not occur in proof obligations, neither are
  2467 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2468 inspect active interpretations of a particular locale.  For details,
  2469 see the Isar Reference manual.  Examples can be found in
  2470 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2471 
  2472 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2473 'interpret' instead.
  2474 
  2475 * New context element 'constrains' for adding type constraints to
  2476 parameters.
  2477 
  2478 * Context expressions: renaming of parameters with syntax
  2479 redeclaration.
  2480 
  2481 * Locale declaration: 'includes' disallowed.
  2482 
  2483 * Proper static binding of attribute syntax -- i.e. types / terms /
  2484 facts mentioned as arguments are always those of the locale definition
  2485 context, independently of the context of later invocations.  Moreover,
  2486 locale operations (renaming and type / term instantiation) are applied
  2487 to attribute arguments as expected.
  2488 
  2489 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2490 actual attributes; rare situations may require Attrib.attribute to
  2491 embed those attributes into Attrib.src that lack concrete syntax.
  2492 Attribute implementations need to cooperate properly with the static
  2493 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2494 Attrib.XXX_thm etc. already do the right thing without further
  2495 intervention.  Only unusual applications -- such as "where" or "of"
  2496 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2497 on the context and the facts involved -- may have to assign parsed
  2498 values to argument tokens explicitly.
  2499 
  2500 * Changed parameter management in theorem generation for long goal
  2501 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2502 theorem statement in rare situations.
  2503 
  2504 * Locale inspection command 'print_locale' omits notes elements.  Use
  2505 'print_locale!' to have them included in the output.
  2506 
  2507 
  2508 *** Provers ***
  2509 
  2510 * Provers/hypsubst.ML: improved version of the subst method, for
  2511 single-step rewriting: it now works in bound variable contexts. New is
  2512 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2513 rewrite a different subterm than the original subst method, which is
  2514 still available as 'simplesubst'.
  2515 
  2516 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2517 and quasi orders.
  2518 
  2519 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2520 reflexive-transitive closure of relations.
  2521 
  2522 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2523 limit (previously hard-coded with a value of 20) user-definable.
  2524 
  2525 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2526 is peformed already.  Object-logics merely need to finish their
  2527 initial simpset configuration as before.  INCOMPATIBILITY.
  2528 
  2529 
  2530 *** HOL ***
  2531 
  2532 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2533 
  2534   syntax (epsilon)
  2535     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2536 
  2537 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2538 and x-symbol; use option '-m epsilon' to get it actually printed.
  2539 Moreover, the mathematically important symbolic identifier \<epsilon>
  2540 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2541 
  2542 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2543 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2544 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2545 support corresponding Isar calculations.
  2546 
  2547 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2548 instead of ":".
  2549 
  2550 * theory SetInterval: changed the syntax for open intervals:
  2551 
  2552   Old       New
  2553   {..n(}    {..<n}
  2554   {)n..}    {n<..}
  2555   {m..n(}   {m..<n}
  2556   {)m..n}   {m<..n}
  2557   {)m..n(}  {m<..<n}
  2558 
  2559 The old syntax is still supported but will disappear in the next
  2560 release.  For conversion use the following Emacs search and replace
  2561 patterns (these are not perfect but work quite well):
  2562 
  2563   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2564   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2565 
  2566 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2567 equalities in commutative rings; method 'algebra' provides a generic
  2568 interface.
  2569 
  2570 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2571 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2572 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2573 be a tuple pattern.
  2574 
  2575 Some new syntax forms are available:
  2576 
  2577   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2578   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2579   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2580   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2581 
  2582 The latter form "\<Sum>x < k. e" used to be based on a separate
  2583 function "Summation", which has been discontinued.
  2584 
  2585 * theory Finite_Set: in structured induction proofs, the insert case
  2586 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2587 (insert F x)'.
  2588 
  2589 * The 'refute' command has been extended to support a much larger
  2590 fragment of HOL, including axiomatic type classes, constdefs and
  2591 typedefs, inductive datatypes and recursion.
  2592 
  2593 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2594 Requires zChaff with proof generation to be installed.  See
  2595 HOL/ex/SAT_Examples.thy for examples.
  2596 
  2597 * Datatype induction via method 'induct' now preserves the name of the
  2598 induction variable. For example, when proving P(xs::'a list) by
  2599 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2600 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2601 in unstructured proof scripts.
  2602 
  2603 * Reworked implementation of records.  Improved scalability for
  2604 records with many fields, avoiding performance problems for type
  2605 inference. Records are no longer composed of nested field types, but
  2606 of nested extension types. Therefore the record type only grows linear
  2607 in the number of extensions and not in the number of fields.  The
  2608 top-level (users) view on records is preserved.  Potential
  2609 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2610 old record representation. The type generated for a record is called
  2611 <record_name>_ext_type.
  2612 
  2613 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2614 proofs triggered by a record definition or a simproc (if
  2615 quick_and_dirty is enabled).  Definitions of large records can take
  2616 quite long.
  2617 
  2618 New simproc record_upd_simproc for simplification of multiple record
  2619 updates enabled by default.  Moreover, trivial updates are also
  2620 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2621 occasionally, since simplification is more powerful by default.
  2622 
  2623 * typedef: proper support for polymorphic sets, which contain extra
  2624 type-variables in the term.
  2625 
  2626 * Simplifier: automatically reasons about transitivity chains
  2627 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2628 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2629 old proofs break occasionally as simplification may now solve more
  2630 goals than previously.
  2631 
  2632 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2633 present.  Works for all partial orders (class "order"), in particular
  2634 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2635 just like y <= x.
  2636 
  2637 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2638 bound variable or a constant then the let is unfolded.  Otherwise
  2639 first a is simplified to b, and then f b is simplified to g. If
  2640 possible we abstract b from g arriving at "let x = b in h x",
  2641 otherwise we unfold the let and arrive at g.  The simproc can be
  2642 enabled/disabled by the reference use_let_simproc.  Potential
  2643 INCOMPATIBILITY since simplification is more powerful by default.
  2644 
  2645 * Classical reasoning: the meson method now accepts theorems as arguments.
  2646 
  2647 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2648 jobs to provide advice on the provability of subgoals.
  2649 
  2650 * Theory OrderedGroup and Ring_and_Field: various additions and
  2651 improvements to faciliate calculations involving equalities and
  2652 inequalities.
  2653 
  2654 The following theorems have been eliminated or modified
  2655 (INCOMPATIBILITY):
  2656 
  2657   abs_eq             now named abs_of_nonneg
  2658   abs_of_ge_0        now named abs_of_nonneg
  2659   abs_minus_eq       now named abs_of_nonpos
  2660   imp_abs_id         now named abs_of_nonneg
  2661   imp_abs_neg_id     now named abs_of_nonpos
  2662   mult_pos           now named mult_pos_pos
  2663   mult_pos_le        now named mult_nonneg_nonneg
  2664   mult_pos_neg_le    now named mult_nonneg_nonpos
  2665   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2666   mult_neg           now named mult_neg_neg
  2667   mult_neg_le        now named mult_nonpos_nonpos
  2668 
  2669 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2670      
  2671      zero_le_square
  2672      not_square_less_zero 
  2673 
  2674   The following lemmas have been deleted from Real/RealPow:
  2675   
  2676      realpow_zero_zero
  2677      realpow_two
  2678      realpow_less
  2679      zero_le_power
  2680      realpow_two_le
  2681      abs_realpow_two
  2682      realpow_two_abs     
  2683 
  2684 * Theory Parity: added rules for simplifying exponents.
  2685 
  2686 * Theory List:
  2687 
  2688 The following theorems have been eliminated or modified
  2689 (INCOMPATIBILITY):
  2690 
  2691   list_all_Nil       now named list_all.simps(1)
  2692   list_all_Cons      now named list_all.simps(2)
  2693   list_all_conv      now named list_all_iff
  2694   set_mem_eq         now named mem_iff
  2695 
  2696 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2697 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2698 
  2699 
  2700 *** HOL-Complex ***
  2701 
  2702 * Theory RealDef: better support for embedding natural numbers and
  2703 integers in the reals.
  2704 
  2705 The following theorems have been eliminated or modified
  2706 (INCOMPATIBILITY):
  2707 
  2708   exp_ge_add_one_self  now requires no hypotheses
  2709   real_of_int_add      reversed direction of equality (use [symmetric])
  2710   real_of_int_minus    reversed direction of equality (use [symmetric])
  2711   real_of_int_diff     reversed direction of equality (use [symmetric])
  2712   real_of_int_mult     reversed direction of equality (use [symmetric])
  2713 
  2714 * Theory RComplete: expanded support for floor and ceiling functions.
  2715 
  2716 * Theory Ln is new, with properties of the natural logarithm
  2717 
  2718 * Hyperreal: There is a new type constructor "star" for making
  2719 nonstandard types.  The old type names are now type synonyms:
  2720 
  2721   hypreal = real star
  2722   hypnat = nat star
  2723   hcomplex = complex star
  2724 
  2725 * Hyperreal: Many groups of similarly-defined constants have been
  2726 replaced by polymorphic versions (INCOMPATIBILITY):
  2727 
  2728   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2729 
  2730   starset      <-- starsetNat, starsetC
  2731   *s*          <-- *sNat*, *sc*
  2732   starset_n    <-- starsetNat_n, starsetC_n
  2733   *sn*         <-- *sNatn*, *scn*
  2734   InternalSets <-- InternalNatSets, InternalCSets
  2735 
  2736   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2737   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2738   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2739   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2740   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2741 
  2742 * Hyperreal: Many type-specific theorems have been removed in favor of
  2743 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2744 
  2745   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2746   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2747   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2748   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2749   right_minus <-- hypreal_add_minus
  2750   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2751   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2752   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2753   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2754   mult_1_right <-- hcomplex_mult_one_right
  2755   mult_zero_left <-- hcomplex_mult_zero_left
  2756   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2757   right_distrib <-- hypnat_add_mult_distrib2
  2758   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2759   right_inverse <-- hypreal_mult_inverse
  2760   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2761   order_refl <-- {hypreal,hypnat}_le_refl
  2762   order_trans <-- {hypreal,hypnat}_le_trans
  2763   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2764   order_less_le <-- {hypreal,hypnat}_less_le
  2765   linorder_linear <-- {hypreal,hypnat}_le_linear
  2766   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2767   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2768   add_nonneg_nonneg <-- hypreal_le_add_order
  2769 
  2770 * Hyperreal: Separate theorems having to do with type-specific
  2771 versions of constants have been merged into theorems that apply to the
  2772 new polymorphic constants (INCOMPATIBILITY):
  2773 
  2774   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2775   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2776   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2777   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2778   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2779   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2780   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2781   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2782   STAR_diff <-- {STAR,STARC}_diff
  2783   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2784     STARC_hcomplex_of_complex}_image_subset
  2785   starset_n_Un <-- starset{Nat,C}_n_Un
  2786   starset_n_Int <-- starset{Nat,C}_n_Int
  2787   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2788   starset_n_diff <-- starset{Nat,C}_n_diff
  2789   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2790   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2791   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2792   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2793   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2794   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2795   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2796   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2797   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2798   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2799   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2800   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2801   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2802   starfun_diff <-- starfun{C,RC,CR}_diff
  2803   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2804   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2805   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2806   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2807   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2808   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2809   starfun_Id <-- starfunC_Id
  2810   starfun_approx <-- starfun{Nat,CR}_approx
  2811   starfun_capprox <-- starfun{C,RC}_capprox
  2812   starfun_abs <-- starfunNat_rabs
  2813   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2814   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2815   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2816   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2817   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2818   starfun_add_approx <-- starfunCR_add_approx
  2819   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2820   starfun_divide <-- starfun{C,CR,RC}_divide
  2821   starfun_n <-- starfun{Nat,C}_n
  2822   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2823   starfun_n_add <-- starfun{Nat,C}_n_add
  2824   starfun_n_add_minus <-- starfunNat_n_add_minus
  2825   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2826   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2827   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2828 
  2829   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2830   star_n_minus <-- {hypreal,hcomplex}_minus
  2831   star_n_diff <-- {hypreal,hcomplex}_diff
  2832   star_n_mult <-- {hypreal,hcomplex}_mult
  2833   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2834   star_n_le <-- {hypreal,hypnat}_le
  2835   star_n_less <-- {hypreal,hypnat}_less
  2836   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2837   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2838   star_n_abs <-- hypreal_hrabs
  2839   star_n_divide <-- hcomplex_divide
  2840 
  2841   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2842   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2843   star_of_diff <-- hypreal_of_real_diff
  2844   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2845   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2846   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2847   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2848   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2849   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2850   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2851   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2852   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2853   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2854   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2855   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2856   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2857   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2858   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2859   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2860   star_of_power <-- hypreal_of_real_power
  2861   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2862 
  2863 * Hyperreal: new method "transfer" that implements the transfer
  2864 principle of nonstandard analysis. With a subgoal that mentions
  2865 nonstandard types like "'a star", the command "apply transfer"
  2866 replaces it with an equivalent one that mentions only standard types.
  2867 To be successful, all free variables must have standard types; non-
  2868 standard variables must have explicit universal quantifiers.
  2869 
  2870 * Hyperreal: A theory of Taylor series.
  2871 
  2872 
  2873 *** HOLCF ***
  2874 
  2875 * Discontinued special version of 'constdefs' (which used to support
  2876 continuous functions) in favor of the general Pure one with full
  2877 type-inference.
  2878 
  2879 * New simplification procedure for solving continuity conditions; it
  2880 is much faster on terms with many nested lambda abstractions (cubic
  2881 instead of exponential time).
  2882 
  2883 * New syntax for domain package: selector names are now optional.
  2884 Parentheses should be omitted unless argument is lazy, for example:
  2885 
  2886   domain 'a stream = cons "'a" (lazy "'a stream")
  2887 
  2888 * New command 'fixrec' for defining recursive functions with pattern
  2889 matching; defining multiple functions with mutual recursion is also
  2890 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2891 sinr, or any data constructor defined by the domain package. The given
  2892 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2893 syntax and examples.
  2894 
  2895 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2896 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2897 but the proof obligation additionally includes an admissibility
  2898 requirement. The packages generate instances of class cpo or pcpo,
  2899 with continuity and strictness theorems for Rep and Abs.
  2900 
  2901 * HOLCF: Many theorems have been renamed according to a more standard naming
  2902 scheme (INCOMPATIBILITY):
  2903 
  2904   foo_inject:  "foo$x = foo$y ==> x = y"
  2905   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2906   foo_less:    "(foo$x << foo$y) = (x << y)"
  2907   foo_strict:  "foo$UU = UU"
  2908   foo_defined: "... ==> foo$x ~= UU"
  2909   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2910 
  2911 
  2912 *** ZF ***
  2913 
  2914 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2915 including the First Isomorphism Theorem (on quotienting by the kernel
  2916 of a homomorphism).
  2917 
  2918 * ZF/Simplifier: install second copy of type solver that actually
  2919 makes use of TC rules declared to Isar proof contexts (or locales);
  2920 the old version is still required for ML proof scripts.
  2921 
  2922 
  2923 *** Cube ***
  2924 
  2925 * Converted to Isar theory format; use locales instead of axiomatic
  2926 theories.
  2927 
  2928 
  2929 *** ML ***
  2930 
  2931 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2932 for ||>, ||>>, |>>,
  2933 
  2934 * Pure/library.ML no longer defines its own option datatype, but uses
  2935 that of the SML basis, which has constructors NONE and SOME instead of
  2936 None and Some, as well as exception Option.Option instead of OPTION.
  2937 The functions the, if_none, is_some, is_none have been adapted
  2938 accordingly, while Option.map replaces apsome.
  2939 
  2940 * Pure/library.ML: the exception LIST has been given up in favour of
  2941 the standard exceptions Empty and Subscript, as well as
  2942 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2943 superceded by the standard hd and tl functions etc.
  2944 
  2945 A number of basic list functions are no longer exported to the ML
  2946 toplevel, as they are variants of predefined functions.  The following
  2947 suggests how one can translate existing code:
  2948 
  2949     rev_append xs ys = List.revAppend (xs, ys)
  2950     nth_elem (i, xs) = List.nth (xs, i)
  2951     last_elem xs = List.last xs
  2952     flat xss = List.concat xss
  2953     seq fs = List.app fs
  2954     partition P xs = List.partition P xs
  2955     mapfilter f xs = List.mapPartial f xs
  2956 
  2957 * Pure/library.ML: several combinators for linear functional
  2958 transformations, notably reverse application and composition:
  2959 
  2960   x |> f                f #> g
  2961   (x, y) |-> f          f #-> g
  2962 
  2963 * Pure/library.ML: introduced/changed precedence of infix operators:
  2964 
  2965   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2966   infix 2 ?;
  2967   infix 3 o oo ooo oooo;
  2968   infix 4 ~~ upto downto;
  2969 
  2970 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2971 infix operators.
  2972 
  2973 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2974 fold_map support linear functional transformations and nesting.  For
  2975 example:
  2976 
  2977   fold f [x1, ..., xN] y =
  2978     y |> f x1 |> ... |> f xN
  2979 
  2980   (fold o fold) f [xs1, ..., xsN] y =
  2981     y |> fold f xs1 |> ... |> fold f xsN
  2982 
  2983   fold f [x1, ..., xN] =
  2984     f x1 #> ... #> f xN
  2985 
  2986   (fold o fold) f [xs1, ..., xsN] =
  2987     fold f xs1 #> ... #> fold f xsN
  2988 
  2989 * Pure/library.ML: the following selectors on type 'a option are
  2990 available:
  2991 
  2992   the:               'a option -> 'a  (*partial*)
  2993   these:             'a option -> 'a  where 'a = 'b list
  2994   the_default: 'a -> 'a option -> 'a
  2995   the_list:          'a option -> 'a list
  2996 
  2997 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2998 basic operations for association lists, following natural argument
  2999 order; moreover the explicit equality predicate passed here avoids
  3000 potentially expensive polymorphic runtime equality checks.
  3001 The old functions may be expressed as follows:
  3002 
  3003   assoc = uncurry (AList.lookup (op =))
  3004   assocs = these oo AList.lookup (op =)
  3005   overwrite = uncurry (AList.update (op =)) o swap
  3006 
  3007 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3008 
  3009   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3010   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3011 
  3012 replacing make_keylist and keyfilter (occassionally used)
  3013 Naive rewrites:
  3014 
  3015   make_keylist = AList.make
  3016   keyfilter = AList.find (op =)
  3017 
  3018 * eq_fst and eq_snd now take explicit equality parameter, thus
  3019   avoiding eqtypes. Naive rewrites:
  3020 
  3021     eq_fst = eq_fst (op =)
  3022     eq_snd = eq_snd (op =)
  3023 
  3024 * Removed deprecated apl and apr (rarely used).
  3025   Naive rewrites:
  3026 
  3027     apl (n, op) =>>= curry op n
  3028     apr (op, m) =>>= fn n => op (n, m)
  3029 
  3030 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3031 provides a reasonably efficient light-weight implementation of sets as
  3032 lists.
  3033 
  3034 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3035 few new operations; existing lookup and update are now curried to
  3036 follow natural argument order (for use with fold etc.);
  3037 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3038 
  3039 * Pure/General: output via the Isabelle channels of
  3040 writeln/warning/error etc. is now passed through Output.output, with a
  3041 hook for arbitrary transformations depending on the print_mode
  3042 (cf. Output.add_mode -- the first active mode that provides a output
  3043 function wins).  Already formatted output may be embedded into further
  3044 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3045 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3046 accommodate easy composition of diagnostic messages etc.  Programmers
  3047 rarely need to care about Output.output or Output.raw at all, with
  3048 some notable exceptions: Output.output is required when bypassing the
  3049 standard channels (writeln etc.), or in token translations to produce
  3050 properly formatted results; Output.raw is required when capturing
  3051 already output material that will eventually be presented to the user
  3052 a second time.  For the default print mode, both Output.output and
  3053 Output.raw have no effect.
  3054 
  3055 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3056 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3057 cumulative results are displayed at the end of a batch session.
  3058 
  3059 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3060 replaced by File.platform_path and File.shell_path (with appropriate
  3061 hooks).  This provides a clean interface for unusual systems where the
  3062 internal and external process view of file names are different.
  3063 
  3064 * Pure: more efficient orders for basic syntactic entities: added
  3065 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3066 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3067 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3068 orders now -- potential INCOMPATIBILITY for code that depends on a
  3069 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3070 Library.sort_strings on result).
  3071 
  3072 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3073 fold_types traverse types/terms from left to right, observing natural
  3074 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3075 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3076 
  3077 * Pure: name spaces have been refined, with significant changes of the
  3078 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3079 to extern(_table).  The plain name entry path is superceded by a
  3080 general 'naming' context, which also includes the 'policy' to produce
  3081 a fully qualified name and external accesses of a fully qualified
  3082 name; NameSpace.extend is superceded by context dependent
  3083 Sign.declare_name.  Several theory and proof context operations modify
  3084 the naming context.  Especially note Theory.restore_naming and
  3085 ProofContext.restore_naming to get back to a sane state; note that
  3086 Theory.add_path is no longer sufficient to recover from
  3087 Theory.absolute_path in particular.
  3088 
  3089 * Pure: new flags short_names (default false) and unique_names
  3090 (default true) for controlling output of qualified names.  If
  3091 short_names is set, names are printed unqualified.  If unique_names is
  3092 reset, the name prefix is reduced to the minimum required to achieve
  3093 the original result when interning again, even if there is an overlap
  3094 with earlier declarations.
  3095 
  3096 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3097 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3098 (useful for printing error messages).  INCOMPATIBILITY.
  3099 
  3100 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3101 Theory.theory are now identified, referring to the universal
  3102 Context.theory (see Pure/context.ML).  Actual signature and theory
  3103 content is managed as theory data.  The old code and interfaces were
  3104 spread over many files and structures; the new arrangement introduces
  3105 considerable INCOMPATIBILITY to gain more clarity:
  3106 
  3107   Context -- theory management operations (name, identity, inclusion,
  3108     parents, ancestors, merge, etc.), plus generic theory data;
  3109 
  3110   Sign -- logical signature and syntax operations (declaring consts,
  3111     types, etc.), plus certify/read for common entities;
  3112 
  3113   Theory -- logical theory operations (stating axioms, definitions,
  3114     oracles), plus a copy of logical signature operations (consts,
  3115     types, etc.); also a few basic management operations (Theory.copy,
  3116     Theory.merge, etc.)
  3117 
  3118 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3119 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3120 for convenience -- they merely return the theory.
  3121 
  3122 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3123 
  3124 * Pure: the Isar proof context type is already defined early in Pure
  3125 as Context.proof (note that ProofContext.context and Proof.context are
  3126 aliases, where the latter is the preferred name).  This enables other
  3127 Isabelle components to refer to that type even before Isar is present.
  3128 
  3129 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3130 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3131 any of these kinds.  For example, Sign.intern typeK is now
  3132 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3133 Theory.hide_types.  Also note that former
  3134 Theory.hide_classes/types/consts are now
  3135 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3136 internalize their arguments!  INCOMPATIBILITY.
  3137 
  3138 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3139 datatype thmref (with constructors Name and NameSelection) instead of
  3140 plain string -- INCOMPATIBILITY;
  3141 
  3142 * Pure: cases produced by proof methods specify options, where NONE
  3143 means to remove case bindings -- INCOMPATIBILITY in
  3144 (RAW_)METHOD_CASES.
  3145 
  3146 * Pure: the following operations retrieve axioms or theorems from a
  3147 theory node or theory hierarchy, respectively:
  3148 
  3149   Theory.axioms_of: theory -> (string * term) list
  3150   Theory.all_axioms_of: theory -> (string * term) list
  3151   PureThy.thms_of: theory -> (string * thm) list
  3152   PureThy.all_thms_of: theory -> (string * thm) list
  3153 
  3154 * Pure: print_tac now outputs the goal through the trace channel.
  3155 
  3156 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3157 Reference Toplevel.debug (default false) controls detailed printing
  3158 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3159 controls execution profiling -- set to 1 for time and 2 for space
  3160 (both increase the runtime).
  3161 
  3162 * Isar session: The initial use of ROOT.ML is now always timed,
  3163 i.e. the log will show the actual process times, in contrast to the
  3164 elapsed wall-clock time that the outer shell wrapper produces.
  3165 
  3166 * Simplifier: improved handling of bound variables (nameless
  3167 representation, avoid allocating new strings).  Simprocs that invoke
  3168 the Simplifier recursively should use Simplifier.inherit_bounds to
  3169 avoid local name clashes.  Failure to do so produces warnings
  3170 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3171 for further details.
  3172 
  3173 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3174 bindings for all theorems stored within a given theory; this may help
  3175 in porting non-Isar theories to Isar ones, while keeping ML proof
  3176 scripts for the time being.
  3177 
  3178 * ML operator HTML.with_charset specifies the charset begin used for
  3179 generated HTML files.  For example:
  3180 
  3181   HTML.with_charset "utf-8" use_thy "Hebrew";
  3182   HTML.with_charset "utf-8" use_thy "Chinese";
  3183 
  3184 
  3185 *** System ***
  3186 
  3187 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3188 isabelle, isatool etc.).
  3189 
  3190 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3191 isatool doc, isatool mkdir, display_drafts etc.).
  3192 
  3193 * isatool usedir: option -f allows specification of the ML file to be
  3194 used by Isabelle; default is ROOT.ML.
  3195 
  3196 * New isatool version outputs the version identifier of the Isabelle
  3197 distribution being used.
  3198 
  3199 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3200 (containing Boolean satisfiability problems) into Isabelle/HOL
  3201 theories.
  3202 
  3203 
  3204 
  3205 New in Isabelle2004 (April 2004)
  3206 --------------------------------
  3207 
  3208 *** General ***
  3209 
  3210 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3211   Replaces linorder.ML.
  3212 
  3213 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3214   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3215   (\<a>...\<z>), are now considered normal letters, and can therefore
  3216   be used anywhere where an ASCII letter (a...zA...Z) has until
  3217   now. COMPATIBILITY: This obviously changes the parsing of some
  3218   terms, especially where a symbol has been used as a binder, say
  3219   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3220   as an identifier.  Fix it by inserting a space around former
  3221   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3222   existing theory and ML files.
  3223 
  3224 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3225 
  3226 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3227   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3228   a normal (but invisible) letter. For multiple letter subscripts repeat
  3229   \<^isub> like this: x\<^isub>1\<^isub>2.
  3230 
  3231 * Pure: There are now sub-/superscripts that can span more than one
  3232   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3233   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3234   superscript. The new control characters are not identifier parts.
  3235 
  3236 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3237   content of "..." to the latex file instead of \isacntrl... . The "..."
  3238   may consist of any printable characters excluding the end bracket >.
  3239 
  3240 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3241   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3242   declare constants "final", which prevents their being given a definition
  3243   later.  It is useful for constants whose behaviour is fixed axiomatically
  3244   rather than definitionally, such as the meta-logic connectives.
  3245 
  3246 * Pure: 'instance' now handles general arities with general sorts
  3247   (i.e. intersections of classes),
  3248 
  3249 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3250   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3251   It can be changed to alter the colors/layout of generated pages.
  3252 
  3253 
  3254 *** Isar ***
  3255 
  3256 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3257   cut_tac, subgoal_tac and thin_tac:
  3258   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3259     locales are no longer forced to write Isar proof scripts.
  3260     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3261     emulations.
  3262   - INCOMPATIBILITY: names of variables to be instantiated may no
  3263     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3264     This is consistent with the instantiation attribute "where".
  3265 
  3266 * Attributes "where" and "of":
  3267   - Now take type variables of instantiated theorem into account when reading
  3268     the instantiation string.  This fixes a bug that caused instantiated
  3269     theorems to have too special types in some circumstances.
  3270   - "where" permits explicit instantiations of type variables.
  3271 
  3272 * Calculation commands "moreover" and "also" no longer interfere with
  3273   current facts ("this"), admitting arbitrary combinations with "then"
  3274   and derived forms.
  3275 
  3276 * Locales:
  3277   - Goal statements involving the context element "includes" no longer
  3278     generate theorems with internal delta predicates (those ending on
  3279     "_axioms") in the premise.
  3280     Resolve particular premise with <locale>.intro to obtain old form.
  3281   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3282     specification and "includes" elements in goal statement.
  3283   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3284     [intro?] and [elim?] (respectively) by default.
  3285   - Experimental command for instantiation of locales in proof contexts:
  3286         instantiate <label>[<attrs>]: <loc>
  3287     Instantiates locale <loc> and adds all its theorems to the current context
  3288     taking into account their attributes.  Label and attrs are optional
  3289     modifiers, like in theorem declarations.  If present, names of
  3290     instantiated theorems are qualified with <label>, and the attributes
  3291     <attrs> are applied after any attributes these theorems might have already.
  3292       If the locale has assumptions, a chained fact of the form
  3293     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3294     are derived.  The command does not support old-style locales declared
  3295     with "locale (open)".
  3296       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3297 
  3298 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3299   (Isar) contexts.
  3300 
  3301 
  3302 *** HOL ***
  3303 
  3304 * Proof import: new image HOL4 contains the imported library from
  3305   the HOL4 system with about 2500 theorems. It is imported by
  3306   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3307   can be used like any other Isabelle image.  See
  3308   HOL/Import/HOL/README for more information.
  3309 
  3310 * Simplifier:
  3311   - Much improved handling of linear and partial orders.
  3312     Reasoners for linear and partial orders are set up for type classes
  3313     "linorder" and "order" respectively, and are added to the default simpset
  3314     as solvers.  This means that the simplifier can build transitivity chains
  3315     to solve goals from the assumptions.
  3316   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3317     of blast or auto after simplification become unnecessary because the goal
  3318     is solved by simplification already.
  3319 
  3320 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3321     all proved in axiomatic type classes for semirings, rings and fields.
  3322 
  3323 * Numerics:
  3324   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3325     now formalized using the Ring_and_Field theory mentioned above.
  3326   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3327     than before, because now they are set up once in a generic manner.
  3328   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3329     Look for the general versions in Ring_and_Field (and Power if they concern
  3330     exponentiation).
  3331 
  3332 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3333 
  3334 * Records:
  3335   - Record types are now by default printed with their type abbreviation
  3336     instead of the list of all field types. This can be configured via
  3337     the reference "print_record_type_abbr".
  3338   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3339     (not enabled by default).
  3340   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3341     EX x. x = sel r to True (not enabled by default).
  3342   - Tactic "record_split_simp_tac" to split and simplify records added.
  3343 
  3344 * 'specification' command added, allowing for definition by
  3345   specification.  There is also an 'ax_specification' command that
  3346   introduces the new constants axiomatically.
  3347 
  3348 * arith(_tac) is now able to generate counterexamples for reals as well.
  3349 
  3350 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3351 
  3352 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3353   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3354 
  3355 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3356   matrix theory to linear programming.
  3357 
  3358 * Unions and Intersections:
  3359   The latex output syntax of UN and INT has been changed
  3360   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3361   i.e. the index formulae has become a subscript.
  3362   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3363 
  3364 * Unions and Intersections over Intervals:
  3365   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3366   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3367   like in normal math, and corresponding versions for < and for intersection.
  3368 
  3369 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3370   lexicographic dictonary ordering has been added as "lexord".
  3371 
  3372 * ML: the legacy theory structures Int and List have been removed. They had
  3373   conflicted with ML Basis Library structures having the same names.
  3374 
  3375 * 'refute' command added to search for (finite) countermodels.  Only works
  3376   for a fragment of HOL.  The installation of an external SAT solver is
  3377   highly recommended.  See "HOL/Refute.thy" for details.
  3378 
  3379 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3380   formulae under an assignment of free variables to random values.
  3381   In contrast to 'refute', it can deal with inductive datatypes,
  3382   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3383   for examples.
  3384 
  3385 
  3386 *** HOLCF ***
  3387 
  3388 * Streams now come with concatenation and are part of the HOLCF image
  3389 
  3390 
  3391 
  3392 New in Isabelle2003 (May 2003)
  3393 ------------------------------
  3394 
  3395 *** General ***
  3396 
  3397 * Provers/simplifier:
  3398 
  3399   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3400     Assumptions are now subject to complete mutual simplification,
  3401     not just from left to right. The simplifier now preserves
  3402     the order of assumptions.
  3403 
  3404     Potential INCOMPATIBILITY:
  3405 
  3406     -- simp sometimes diverges where the old version did
  3407        not, e.g. invoking simp on the goal
  3408 
  3409         [| P (f x); y = x; f x = f y |] ==> Q
  3410 
  3411        now gives rise to the infinite reduction sequence
  3412 
  3413         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3414 
  3415        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3416        kind of problem.
  3417 
  3418     -- Tactics combining classical reasoner and simplification (such as auto)
  3419        are also affected by this change, because many of them rely on
  3420        simp. They may sometimes diverge as well or yield a different numbers
  3421        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3422        in case of problems. Sometimes subsequent calls to the classical
  3423        reasoner will fail because a preceeding call to the simplifier too
  3424        eagerly simplified the goal, e.g. deleted redundant premises.
  3425 
  3426   - The simplifier trace now shows the names of the applied rewrite rules
  3427 
  3428   - You can limit the number of recursive invocations of the simplifier
  3429     during conditional rewriting (where the simplifie tries to solve the
  3430     conditions before applying the rewrite rule):
  3431     ML "simp_depth_limit := n"
  3432     where n is an integer. Thus you can force termination where previously
  3433     the simplifier would diverge.
  3434 
  3435   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3436 
  3437   - No longer aborts on failed congruence proof.  Instead, the
  3438     congruence is ignored.
  3439 
  3440 * Pure: New generic framework for extracting programs from constructive
  3441   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3442   as HOL/Extraction for some case studies.
  3443 
  3444 * Pure: The main goal of the proof state is no longer shown by default, only
  3445 the subgoals. This behaviour is controlled by a new flag.
  3446    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3447 (ML: Proof.show_main_goal).
  3448 
  3449 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3450 rules whose conclusion matches subgoal 1:
  3451       PG menu: Isabelle/Isar -> Show me -> matching rules
  3452 The rules are ordered by how closely they match the subgoal.
  3453 In particular, rules that solve a subgoal outright are displayed first
  3454 (or rather last, the way they are printed).
  3455 (ML: ProofGeneral.print_intros())
  3456 
  3457 * Pure: New flag trace_unify_fail causes unification to print
  3458 diagnostic information (PG: in trace buffer) when it fails. This is
  3459 useful for figuring out why single step proofs like rule, erule or
  3460 assumption failed.
  3461 
  3462 * Pure: Locale specifications now produce predicate definitions
  3463 according to the body of text (covering assumptions modulo local
  3464 definitions); predicate "loc_axioms" covers newly introduced text,
  3465 while "loc" is cumulative wrt. all included locale expressions; the
  3466 latter view is presented only on export into the global theory
  3467 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3468 on the old view without predicates;
  3469 
  3470 * Pure: predefined locales "var" and "struct" are useful for sharing
  3471 parameters (as in CASL, for example); just specify something like
  3472 ``var x + var y + struct M'' as import;
  3473 
  3474 * Pure: improved thms_containing: proper indexing of facts instead of
  3475 raw theorems; check validity of results wrt. current name space;
  3476 include local facts of proof configuration (also covers active
  3477 locales), cover fixed variables in index; may use "_" in term
  3478 specification; an optional limit for the number of printed facts may
  3479 be given (the default is 40);
  3480 
  3481 * Pure: disallow duplicate fact bindings within new-style theory files
  3482 (batch-mode only);
  3483 
  3484 * Provers: improved induct method: assumptions introduced by case
  3485 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3486 the goal statement); "foo" still refers to all facts collectively;
  3487 
  3488 * Provers: the function blast.overloaded has been removed: all constants
  3489 are regarded as potentially overloaded, which improves robustness in exchange
  3490 for slight decrease in efficiency;
  3491 
  3492 * Provers/linorder: New generic prover for transitivity reasoning over
  3493 linear orders.  Note: this prover is not efficient!
  3494 
  3495 * Isar: preview of problems to finish 'show' now produce an error
  3496 rather than just a warning (in interactive mode);
  3497 
  3498 
  3499 *** HOL ***
  3500 
  3501 * arith(_tac)
  3502 
  3503  - Produces a counter example if it cannot prove a goal.
  3504    Note that the counter example may be spurious if the goal is not a formula
  3505    of quantifier-free linear arithmetic.
  3506    In ProofGeneral the counter example appears in the trace buffer.
  3507 
  3508  - Knows about div k and mod k where k is a numeral of type nat or int.
  3509 
  3510  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3511    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3512    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3513 
  3514 * simp's arithmetic capabilities have been enhanced a bit: it now
  3515 takes ~= in premises into account (by performing a case split);
  3516 
  3517 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3518 are distributed over a sum of terms;
  3519 
  3520 * New tactic "trans_tac" and method "trans" instantiate
  3521 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3522 "<=", "<" and "=").
  3523 
  3524 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3525 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3526 
  3527 * 'typedef' command has new option "open" to suppress the set
  3528 definition;
  3529 
  3530 * functions Min and Max on finite sets have been introduced (theory
  3531 Finite_Set);
  3532 
  3533 * attribute [symmetric] now works for relations as well; it turns
  3534 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3535 
  3536 * induct over a !!-quantified statement (say !!x1..xn):
  3537   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3538 
  3539 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3540 %x. None. Warning: empty_def now refers to the previously hidden definition
  3541 of the empty set.
  3542 
  3543 * Algebra: formalization of classical algebra.  Intended as base for
  3544 any algebraic development in Isabelle.  Currently covers group theory
  3545 (up to Sylow's theorem) and ring theory (Universal Property of
  3546 Univariate Polynomials).  Contributions welcome;
  3547 
  3548 * GroupTheory: deleted, since its material has been moved to Algebra;
  3549 
  3550 * Complex: new directory of the complex numbers with numeric constants,
  3551 nonstandard complex numbers, and some complex analysis, standard and
  3552 nonstandard (Jacques Fleuriot);
  3553 
  3554 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3555 
  3556 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3557 Fleuriot);
  3558 
  3559 * Real/HahnBanach: updated and adapted to locales;
  3560 
  3561 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3562 Gray and Kramer);
  3563 
  3564 * UNITY: added the Meier-Sanders theory of progress sets;
  3565 
  3566 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3567 as abstract algorithms, instantiated to the JVM;
  3568 
  3569 * Bali: Java source language formalization. Type system, operational
  3570 semantics, axiomatic semantics. Supported language features:
  3571 classes, interfaces, objects,virtual methods, static methods,
  3572 static/instance fields, arrays, access modifiers, definite
  3573 assignment, exceptions.
  3574 
  3575 
  3576 *** ZF ***
  3577 
  3578 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3579 universe, etc.);
  3580 
  3581 * Main ZF: virtually all theories converted to new-style format;
  3582 
  3583 
  3584 *** ML ***
  3585 
  3586 * Pure: Tactic.prove provides sane interface for internal proofs;
  3587 omits the infamous "standard" operation, so this is more appropriate
  3588 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3589 
  3590 * Pure: improved error reporting of simprocs;
  3591 
  3592 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3593 up simprocs;
  3594 
  3595 
  3596 *** Document preparation ***
  3597 
  3598 * uses \par instead of \\ for line breaks in theory text. This may
  3599 shift some page breaks in large documents. To get the old behaviour
  3600 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3601 
  3602 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3603 other packages
  3604 
  3605 * \<euro> now needs package babel/greek instead of marvosym (which
  3606 broke \Rightarrow)
  3607 
  3608 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3609 textcomp package)
  3610 
  3611 
  3612 
  3613 New in Isabelle2002 (March 2002)
  3614 --------------------------------
  3615 
  3616 *** Document preparation ***
  3617 
  3618 * greatly simplified document preparation setup, including more
  3619 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3620 instructive isatool mkdir; users should basically be able to get
  3621 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3622 users may run a separate document processing stage manually like this:
  3623 "isatool usedir -D output HOL Test && isatool document Test/output";
  3624 
  3625 * theory dependency graph may now be incorporated into documents;
  3626 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3627 with \includegraphics of LaTeX;
  3628 
  3629 * proper spacing of consecutive markup elements, especially text
  3630 blocks after section headings;
  3631 
  3632 * support bold style (for single symbols only), input syntax is like
  3633 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3634 
  3635 * \<bullet> is now output as bold \cdot by default, which looks much
  3636 better in printed text;
  3637 
  3638 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3639 note that these symbols are currently unavailable in Proof General /
  3640 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3641 
  3642 * isatool latex no longer depends on changed TEXINPUTS, instead
  3643 isatool document copies the Isabelle style files to the target
  3644 location;
  3645 
  3646 
  3647 *** Isar ***
  3648 
  3649 * Pure/Provers: improved proof by cases and induction;
  3650   - 'case' command admits impromptu naming of parameters (such as
  3651     "case (Suc n)");
  3652   - 'induct' method divinates rule instantiation from the inductive
  3653     claim; no longer requires excessive ?P bindings for proper
  3654     instantiation of cases;
  3655   - 'induct' method properly enumerates all possibilities of set/type
  3656     rules; as a consequence facts may be also passed through *type*
  3657     rules without further ado;
  3658   - 'induct' method now derives symbolic cases from the *rulified*
  3659     rule (before it used to rulify cases stemming from the internal
  3660     atomized version); this means that the context of a non-atomic
  3661     statement becomes is included in the hypothesis, avoiding the
  3662     slightly cumbersome show "PROP ?case" form;
  3663   - 'induct' may now use elim-style induction rules without chaining
  3664     facts, using ``missing'' premises from the goal state; this allows
  3665     rules stemming from inductive sets to be applied in unstructured
  3666     scripts, while still benefitting from proper handling of non-atomic
  3667     statements; NB: major inductive premises need to be put first, all
  3668     the rest of the goal is passed through the induction;
  3669   - 'induct' proper support for mutual induction involving non-atomic
  3670     rule statements (uses the new concept of simultaneous goals, see
  3671     below);
  3672   - append all possible rule selections, but only use the first
  3673     success (no backtracking);
  3674   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3675   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3676   - added 'print_induct_rules' (covered by help item in recent Proof
  3677     General versions);
  3678   - moved induct/cases attributes to Pure, methods to Provers;
  3679   - generic method setup instantiated for FOL and HOL;
  3680 
  3681 * Pure: support multiple simultaneous goal statements, for example
  3682 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3683 meta-level mechanism, this acts as if several individual goals had
  3684 been stated separately; in particular common proof methods need to be
  3685 repeated in order to cover all claims; note that a single elimination
  3686 step is *not* sufficient to establish the two conjunctions, so this
  3687 fails:
  3688 
  3689   assume "A & B" then have A and B ..   (*".." fails*)
  3690 
  3691 better use "obtain" in situations as above; alternative refer to
  3692 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3693 
  3694 * Pure: proper integration with ``locales''; unlike the original
  3695 version by Florian Kammller, Isar locales package high-level proof
  3696 contexts rather than raw logical ones (e.g. we admit to include
  3697 attributes everywhere); operations on locales include merge and
  3698 rename; support for implicit arguments (``structures''); simultaneous
  3699 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3700 some examples;
  3701 
  3702 * Pure: the following commands have been ``localized'', supporting a
  3703 target locale specification "(in name)": 'lemma', 'theorem',
  3704 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3705 stored both within the locale and at the theory level (exported and
  3706 qualified by the locale name);
  3707 
  3708 * Pure: theory goals may now be specified in ``long'' form, with
  3709 ad-hoc contexts consisting of arbitrary locale elements. for example
  3710 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3711 definitions may be given, too); the result is a meta-level rule with
  3712 the context elements being discharged in the obvious way;
  3713 
  3714 * Pure: new proof command 'using' allows to augment currently used
  3715 facts after a goal statement ('using' is syntactically analogous to
  3716 'apply', but acts on the goal's facts only); this allows chained facts
  3717 to be separated into parts given before and after a claim, as in
  3718 ``from a and b have C using d and e <proof>'';
  3719 
  3720 * Pure: renamed "antecedent" case to "rule_context";
  3721 
  3722 * Pure: new 'judgment' command records explicit information about the
  3723 object-logic embedding (used by several tools internally); no longer
  3724 use hard-wired "Trueprop";
  3725 
  3726 * Pure: added 'corollary' command;
  3727 
  3728 * Pure: fixed 'token_translation' command;
  3729 
  3730 * Pure: removed obsolete 'exported' attribute;
  3731 
  3732 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3733 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3734 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3735 
  3736 * Pure: method 'atomize' presents local goal premises as object-level
  3737 statements (atomic meta-level propositions); setup controlled via
  3738 rewrite rules declarations of 'atomize' attribute; example
  3739 application: 'induct' method with proper rule statements in improper
  3740 proof *scripts*;
  3741 
  3742 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3743 now consider the syntactic context of assumptions, giving a better
  3744 chance to get type-inference of the arguments right (this is
  3745 especially important for locales);
  3746 
  3747 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3748 mode;
  3749 
  3750 * Pure/obtain: the formal conclusion "thesis", being marked as
  3751 ``internal'', may no longer be reference directly in the text;
  3752 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3753 situations;
  3754 
  3755 * Pure: generic 'sym' attribute which declares a rule both as pure
  3756 'elim?' and for the 'symmetric' operation;
  3757 
  3758 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3759 text; the fixed correlation with particular command syntax has been
  3760 discontinued;
  3761 
  3762 * Pure: new method 'rules' is particularly well-suited for proof
  3763 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3764 but often produces more compact proof terms with less detours;
  3765 
  3766 * Pure/Provers/classical: simplified integration with pure rule
  3767 attributes and methods; the classical "intro?/elim?/dest?"
  3768 declarations coincide with the pure ones; the "rule" method no longer
  3769 includes classically swapped intros; "intro" and "elim" methods no
  3770 longer pick rules from the context; also got rid of ML declarations
  3771 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3772 INCOMPATIBILITY;
  3773 
  3774 * Provers/classical: attribute 'swapped' produces classical inversions
  3775 of introduction rules;
  3776 
  3777 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3778 rules instead of full simplifier context; 'iff' attribute handles
  3779 conditional rules;
  3780 
  3781 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3782 
  3783 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3784 "(permissive)" option to recover old behavior;
  3785 
  3786 * HOL: 'inductive' no longer features separate (collective) attributes
  3787 for 'intros' (was found too confusing);
  3788 
  3789 * HOL: properly declared induction rules less_induct and
  3790 wf_induct_rule;
  3791 
  3792 
  3793 *** HOL ***
  3794 
  3795 * HOL: moved over to sane numeral syntax; the new policy is as
  3796 follows:
  3797 
  3798   - 0 and 1 are polymorphic constants, which are defined on any
  3799   numeric type (nat, int, real etc.);
  3800 
  3801   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3802   binary representation internally;
  3803 
  3804   - type nat has special constructor Suc, and generally prefers Suc 0
  3805   over 1::nat and Suc (Suc 0) over 2::nat;
  3806 
  3807 This change may cause significant problems of INCOMPATIBILITY; here
  3808 are some hints on converting existing sources:
  3809 
  3810   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3811   entities, so expressions involving "-" (unary or binary minus) need
  3812   to be spaced properly;
  3813 
  3814   - existing occurrences of "1" may need to be constraint "1::nat" or
  3815   even replaced by Suc 0; similar for old "2";
  3816 
  3817   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3818 
  3819   - remove all special provisions on numerals in proofs;
  3820 
  3821 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3822 representation (depends on bin_arith_simps in the default context);
  3823 
  3824 * HOL: symbolic syntax for x^2 (numeral 2);
  3825 
  3826 * HOL: the class of all HOL types is now called "type" rather than
  3827 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3828 in axclass/classes, instance/arities, and (usually rare) occurrences
  3829 in typings (of consts etc.); internally the class is called
  3830 "HOL.type", ML programs should refer to HOLogic.typeS;
  3831 
  3832 * HOL/record package improvements:
  3833   - new derived operations "fields" to build a partial record section,
  3834     "extend" to promote a fixed record to a record scheme, and
  3835     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3836     declared as simp by default;
  3837   - shared operations ("more", "fields", etc.) now need to be always
  3838     qualified) --- potential INCOMPATIBILITY;
  3839   - removed "make_scheme" operations (use "make" with "extend") --
  3840     INCOMPATIBILITY;
  3841   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3842   - provides cases/induct rules for use with corresponding Isar
  3843     methods (for concrete records, record schemes, concrete more
  3844     parts, and schematic more parts -- in that order);
  3845   - internal definitions directly based on a light-weight abstract
  3846     theory of product types over typedef rather than datatype;
  3847 
  3848 * HOL: generic code generator for generating executable ML code from
  3849 specifications; specific support for HOL constructs such as inductive
  3850 datatypes and sets, as well as recursive functions; can be invoked
  3851 via 'generate_code' theory section;
  3852 
  3853 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3854 
  3855 * HOL: consolidated and renamed several theories.  In particular:
  3856         Ord.thy has been absorbed into HOL.thy
  3857         String.thy has been absorbed into List.thy
  3858 
  3859 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3860 (beware of argument permutation!);
  3861 
  3862 * HOL: linorder_less_split superseded by linorder_cases;
  3863 
  3864 * HOL/List: "nodups" renamed to "distinct";
  3865 
  3866 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3867 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3868   - Ex_def has changed, now need to use some_eq_ex
  3869 
  3870 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3871 in this (rare) case use:
  3872 
  3873   delSWrapper "split_all_tac"
  3874   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3875 
  3876 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3877 MAY FAIL;
  3878 
  3879 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3880 Isabelle's type classes, ^ on functions and relations has too general
  3881 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3882 necessary to attach explicit type constraints;
  3883 
  3884 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3885 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3886 renamed accordingly (eg "compI" -> "rel_compI").
  3887 
  3888 * HOL: syntax translations now work properly with numerals and records
  3889 expressions;
  3890 
  3891 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3892 of "lam" -- INCOMPATIBILITY;
  3893 
  3894 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3895 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3896 renamed "Product_Type.unit";
  3897 
  3898 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3899 
  3900 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3901 the "cases" method);
  3902 
  3903 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3904 Florian Kammller);
  3905 
  3906 * HOL/IMP: updated and converted to new-style theory format; several
  3907 parts turned into readable document, with proper Isar proof texts and
  3908 some explanations (by Gerwin Klein);
  3909 
  3910 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3911 
  3912 * HOL-Hyperreal is now a logic image;
  3913 
  3914 
  3915 *** HOLCF ***
  3916 
  3917 * Isar: consts/constdefs supports mixfix syntax for continuous
  3918 operations;
  3919 
  3920 * Isar: domain package adapted to new-style theory format, e.g. see
  3921 HOLCF/ex/Dnat.thy;
  3922 
  3923 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3924 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3925 lift.induct_tac, always use UU instead of Undef;
  3926 
  3927 * HOLCF/IMP: updated and converted to new-style theory;
  3928 
  3929 
  3930 *** ZF ***
  3931 
  3932 * Isar: proper integration of logic-specific tools and packages,
  3933 including theory commands '(co)inductive', '(co)datatype',
  3934 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3935 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3936 
  3937 * theory Main no longer includes AC; for the Axiom of Choice, base
  3938 your theory on Main_ZFC;
  3939 
  3940 * the integer library now covers quotients and remainders, with many
  3941 laws relating division to addition, multiplication, etc.;
  3942 
  3943 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3944 typeless version of the formalism;
  3945 
  3946 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3947 format;
  3948 
  3949 * ZF/Induct: new directory for examples of inductive definitions,
  3950 including theory Multiset for multiset orderings; converted to
  3951 new-style theory format;
  3952 
  3953 * ZF: many new theorems about lists, ordinals, etc.;
  3954 
  3955 
  3956 *** General ***
  3957 
  3958 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3959 variable proof controls level of detail: 0 = no proofs (only oracle
  3960 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3961 also ref manual for further ML interfaces;
  3962 
  3963 * Pure/axclass: removed obsolete ML interface
  3964 goal_subclass/goal_arity;
  3965 
  3966 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3967 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3968 separate tokens, so expressions involving minus need to be spaced
  3969 properly;
  3970 
  3971 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3972 rather than "infixl" or "infixr";
  3973 
  3974 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3975 sort constraint specifications in type inference; e.g. "x::_::foo"
  3976 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3977 type variable);
  3978 
  3979 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3980 control output of nested => (types); the default behavior is
  3981 "type_brackets";
  3982 
  3983 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3984 tokens into AST constants;
  3985 
  3986 * Pure/syntax: prefer later declarations of translations and print
  3987 translation functions; potential INCOMPATIBILITY: need to reverse
  3988 multiple declarations for same syntax element constant;
  3989 
  3990 * Pure/show_hyps reset by default (in accordance to existing Isar
  3991 practice);
  3992 
  3993 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3994 addSafter;
  3995 
  3996 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3997 as well;
  3998 
  3999 * system: tested support for MacOS X; should be able to get Isabelle +
  4000 Proof General to work in a plain Terminal after installing Poly/ML
  4001 (e.g. from the Isabelle distribution area) and GNU bash alone
  4002 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4003 support requires further installations, e.g. from
  4004 http://fink.sourceforge.net/);
  4005 
  4006 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4007 
  4008 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4009 of 40 MB), cf. ML_OPTIONS;
  4010 
  4011 * system: Proof General keywords specification is now part of the
  4012 Isabelle distribution (see etc/isar-keywords.el);
  4013 
  4014 * system: support for persistent Proof General sessions (refrain from
  4015 outdating all loaded theories on startup); user may create writable
  4016 logic images like this: ``isabelle -q HOL Test'';
  4017 
  4018 * system: smart selection of Isabelle process versus Isabelle
  4019 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4020 run both "isabelle" and "Isabelle" even if file names are badly
  4021 damaged (executable inspects the case of the first letter of its own
  4022 name); added separate "isabelle-process" and "isabelle-interface";
  4023 
  4024 * system: refrain from any attempt at filtering input streams; no
  4025 longer support ``8bit'' encoding of old isabelle font, instead proper
  4026 iso-latin characters may now be used; the related isatools
  4027 "symbolinput" and "nonascii" have disappeared as well;
  4028 
  4029 * system: removed old "xterm" interface (the print modes "xterm" and
  4030 "xterm_color" are still available for direct use in a suitable
  4031 terminal);
  4032 
  4033 
  4034 
  4035 New in Isabelle99-2 (February 2001)
  4036 -----------------------------------
  4037 
  4038 *** Overview of INCOMPATIBILITIES ***
  4039 
  4040 * HOL: please note that theories in the Library and elsewhere often use the
  4041 new-style (Isar) format; to refer to their theorems in an ML script you must
  4042 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4043 
  4044 * HOL: inductive package no longer splits induction rule aggressively,
  4045 but only as far as specified by the introductions given; the old
  4046 format may be recovered via ML function complete_split_rule or attribute
  4047 'split_rule (complete)';
  4048 
  4049 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4050 gfp_Tarski to gfp_unfold;
  4051 
  4052 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4053 
  4054 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4055 relation); infix "^^" has been renamed "``"; infix "``" has been
  4056 renamed "`"; "univalent" has been renamed "single_valued";
  4057 
  4058 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4059 operation;
  4060 
  4061 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4062 
  4063 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4064 
  4065 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4066 consequence, it is no longer monotonic wrt. the local goal context
  4067 (which is now passed through the inductive cases);
  4068 
  4069 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4070 \<gg> to \<ggreater>;
  4071 
  4072 
  4073 *** Document preparation ***
  4074 
  4075 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4076 available: are "it" for near math-mode best-style output, "sl" for
  4077 slanted text style, and "tt" for plain type-writer; if no
  4078 \isabellestyle command is given, output is according to slanted
  4079 type-writer);
  4080 
  4081 * support sub/super scripts (for single symbols only), input syntax is
  4082 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4083 
  4084 * some more standard symbols; see Appendix A of the system manual for
  4085 the complete list of symbols defined in isabellesym.sty;
  4086 
  4087 * improved isabelle style files; more abstract symbol implementation
  4088 (should now use \isamath{...} and \isatext{...} in custom symbol
  4089 definitions);
  4090 
  4091 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4092 state; Note that presentation of goal states does not conform to
  4093 actual human-readable proof documents.  Please do not include goal
  4094 states into document output unless you really know what you are doing!
  4095 
  4096 * proper indentation of antiquoted output with proportional LaTeX
  4097 fonts;
  4098 
  4099 * no_document ML operator temporarily disables LaTeX document
  4100 generation;
  4101 
  4102 * isatool unsymbolize tunes sources for plain ASCII communication;
  4103 
  4104 
  4105 *** Isar ***
  4106 
  4107 * Pure: Isar now suffers initial goal statements to contain unbound
  4108 schematic variables (this does not conform to actual readable proof
  4109 documents, due to unpredictable outcome and non-compositional proof
  4110 checking); users who know what they are doing may use schematic goals
  4111 for Prolog-style synthesis of proven results;
  4112 
  4113 * Pure: assumption method (an implicit finishing) now handles actual
  4114 rules as well;
  4115 
  4116 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4117 initial goal, declare "that" only as Pure intro (only for single
  4118 steps); the "that" rule assumption may now be involved in implicit
  4119 finishing, thus ".." becomes a feasible for trivial obtains;
  4120 
  4121 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4122 instance proofs may be performed by "..";
  4123 
  4124 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4125 statements as well;
  4126 
  4127 * Pure: more robust selection of calculational rules;
  4128 
  4129 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4130 rule (as well as the assumption rule);
  4131 
  4132 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4133 lemmas, using the graph browser tool;
  4134 
  4135 * Pure: predict failure of "show" in interactive mode;
  4136 
  4137 * Pure: 'thms_containing' now takes actual terms as arguments;
  4138 
  4139 * HOL: improved method 'induct' --- now handles non-atomic goals
  4140 (potential INCOMPATIBILITY); tuned error handling;
  4141 
  4142 * HOL: cases and induct rules now provide explicit hints about the
  4143 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4144 any remaining facts are inserted into the goal verbatim;
  4145 
  4146 * HOL: local contexts (aka cases) may now contain term bindings as
  4147 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4148 the result to be shown in each case;
  4149 
  4150 * HOL: added 'recdef_tc' command;
  4151 
  4152 * isatool convert assists in eliminating legacy ML scripts;
  4153 
  4154 
  4155 *** HOL ***
  4156 
  4157 * HOL/Library: a collection of generic theories to be used together
  4158 with main HOL; the theory loader path already includes this directory
  4159 by default; the following existing theories have been moved here:
  4160 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4161 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4162 
  4163 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4164 modelling and verification task performed in Isabelle/HOL +
  4165 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4166 
  4167 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4168 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4169 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4170 'domain', this makes the theory consistent with mathematical
  4171 literature;
  4172 
  4173 * HOL basics: added overloaded operations "inverse" and "divide"
  4174 (infix "/"), syntax for generic "abs" operation, generic summation
  4175 operator \<Sum>;
  4176 
  4177 * HOL/typedef: simplified package, provide more useful rules (see also
  4178 HOL/subset.thy);
  4179 
  4180 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4181 now expressed as a proper nested rule (old-style tactic scripts may
  4182 require atomize_strip_tac to cope with non-atomic premises);
  4183 
  4184 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4185 to "split_conv" (old name still available for compatibility);
  4186 
  4187 * HOL: improved concrete syntax for strings (e.g. allows translation
  4188 rules with string literals);
  4189 
  4190 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4191  and Fleuriot's mechanization of analysis, including the transcendental
  4192  functions for the reals;
  4193 
  4194 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4195 
  4196 
  4197 *** CTT ***
  4198 
  4199 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4200 "lam" is displayed as TWO lambda-symbols
  4201 
  4202 * CTT: theory Main now available, containing everything (that is, Bool
  4203 and Arith);
  4204 
  4205 
  4206 *** General ***
  4207 
  4208 * Pure: the Simplifier has been implemented properly as a derived rule
  4209 outside of the actual kernel (at last!); the overall performance
  4210 penalty in practical applications is about 50%, while reliability of
  4211 the Isabelle inference kernel has been greatly improved;
  4212 
  4213 * print modes "brackets" and "no_brackets" control output of nested =>
  4214 (types) and ==> (props); the default behaviour is "brackets";
  4215 
  4216 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4217 as assumptions as well;
  4218 
  4219 * system: support Poly/ML 4.0;
  4220 
  4221 * system: isatool install handles KDE version 1 or 2;
  4222 
  4223 
  4224 
  4225 New in Isabelle99-1 (October 2000)
  4226 ----------------------------------
  4227 
  4228 *** Overview of INCOMPATIBILITIES ***
  4229 
  4230 * HOL: simplification of natural numbers is much changed; to partly
  4231 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4232 issue the following ML commands:
  4233 
  4234   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4235   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4236 
  4237 * HOL: simplification no longer dives into case-expressions; this is
  4238 controlled by "t.weak_case_cong" for each datatype t;
  4239 
  4240 * HOL: nat_less_induct renamed to less_induct;
  4241 
  4242 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4243 fixsome to patch .thy and .ML sources automatically;
  4244 
  4245   select_equality  -> some_equality
  4246   select_eq_Ex     -> some_eq_ex
  4247   selectI2EX       -> someI2_ex
  4248   selectI2         -> someI2
  4249   selectI          -> someI
  4250   select1_equality -> some1_equality
  4251   Eps_sym_eq       -> some_sym_eq_trivial
  4252   Eps_eq           -> some_eq_trivial
  4253 
  4254 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4255 
  4256 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4257 instead);
  4258 
  4259 * HOL: the recursion equations generated by 'recdef' are now called
  4260 f.simps instead of f.rules;
  4261 
  4262 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4263 
  4264 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4265 sometimes be needed;
  4266 
  4267 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4268 
  4269 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4270 
  4271 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4272 product is now "<*>" instead of "Times"; the lexicographic product is
  4273 now "<*lex*>" instead of "**";
  4274 
  4275 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4276 of main HOL, but was unused); better use HOL's datatype package;
  4277 
  4278 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4279 the old syntax may be recovered as follows:
  4280 
  4281   syntax (symbols)
  4282     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4283       (infixl "\\<oplus>" 100)
  4284 
  4285 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4286 
  4287 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4288 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4289 internally;
  4290 
  4291 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4292 changed from A/r to A//r;
  4293 
  4294 * ZF: new treatment of arithmetic (nat & int) may break some old
  4295 proofs;
  4296 
  4297 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4298 rulify -> rule_format, elimify -> elim_format, ...);
  4299 
  4300 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4301 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4302 should have to change intro!! to intro? only); replaced "delrule" by
  4303 "rule del";
  4304 
  4305 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4306 
  4307 * Provers: strengthened force_tac by using new first_best_tac;
  4308 
  4309 * LaTeX document preparation: several changes of isabelle.sty (see
  4310 lib/texinputs);
  4311 
  4312 
  4313 *** Document preparation ***
  4314 
  4315 * formal comments (text blocks etc.) in new-style theories may now
  4316 contain antiquotations of thm/prop/term/typ/text to be presented
  4317 according to latex print mode; concrete syntax is like this:
  4318 @{term[show_types] "f(x) = a + x"};
  4319 
  4320 * isatool mkdir provides easy setup of Isabelle session directories,
  4321 including proper document sources;
  4322 
  4323 * generated LaTeX sources are now deleted after successful run
  4324 (isatool document -c); may retain a copy somewhere else via -D option
  4325 of isatool usedir;
  4326 
  4327 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4328 style files, achieving self-contained LaTeX sources and simplifying
  4329 LaTeX debugging;
  4330 
  4331 * old-style theories now produce (crude) LaTeX output as well;
  4332 
  4333 * browser info session directories are now self-contained (may be put
  4334 on WWW server seperately); improved graphs of nested sessions; removed
  4335 graph for 'all sessions';
  4336 
  4337 * several improvements in isabelle style files; \isabellestyle{it}
  4338 produces fake math mode output; \isamarkupheader is now \section by
  4339 default; see lib/texinputs/isabelle.sty etc.;
  4340 
  4341 
  4342 *** Isar ***
  4343 
  4344 * Isar/Pure: local results and corresponding term bindings are now
  4345 subject to Hindley-Milner polymorphism (similar to ML); this
  4346 accommodates incremental type-inference very nicely;
  4347 
  4348 * Isar/Pure: new derived language element 'obtain' supports
  4349 generalized existence reasoning;
  4350 
  4351 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4352 support accumulation of results, without applying any rules yet;
  4353 useful to collect intermediate results without explicit name
  4354 references, and for use with transitivity rules with more than 2
  4355 premises;
  4356 
  4357 * Isar/Pure: scalable support for case-analysis type proofs: new
  4358 'case' language element refers to local contexts symbolically, as
  4359 produced by certain proof methods; internally, case names are attached
  4360 to theorems as "tags";
  4361 
  4362 * Isar/Pure: theory command 'hide' removes declarations from
  4363 class/type/const name spaces;
  4364 
  4365 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4366 indicate potential overloading;
  4367 
  4368 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4369 
  4370 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4371 "{a,b,c}" instead of {a,b,c};
  4372 
  4373 * Isar/Pure now provides its own version of intro/elim/dest
  4374 attributes; useful for building new logics, but beware of confusion
  4375 with the version in Provers/classical;
  4376 
  4377 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4378 case name 'antecedent';
  4379 
  4380 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4381 to the current context is now done automatically);
  4382 
  4383 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4384 for definining proof methods in ML;
  4385 
  4386 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4387 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4388 most cases, one should have to change intro!! to intro? only);
  4389 replaced "delrule" by "rule del";
  4390 
  4391 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4392 'symmetric' attribute (the latter supercedes [RS sym]);
  4393 
  4394 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4395 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4396 well (including splits);
  4397 
  4398 * Isar/Provers: Simplifier and Classical methods now support all kind
  4399 of modifiers used in the past, including 'cong', 'iff', etc.
  4400 
  4401 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4402 of Simplifier and Classical reasoner);
  4403 
  4404 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4405 now support named cases; major packages (inductive, datatype, primrec,
  4406 recdef) support case names and properly name parameters;
  4407 
  4408 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4409 monotonicity conditions are extracted to be proven at end of
  4410 calculations;
  4411 
  4412 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4413 method anyway;
  4414 
  4415 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4416 split_if split_if_asm; datatype package provides theorems foo.splits =
  4417 foo.split foo.split_asm for each datatype;
  4418 
  4419 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4420 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4421 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4422 use "(cases (simplified))" method in proper proof texts);
  4423 
  4424 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4425 
  4426 * Isar: names of theorems etc. may be natural numbers as well;
  4427 
  4428 * Isar: 'pr' command: optional arguments for goals_limit and
  4429 ProofContext.prems_limit; no longer prints theory contexts, but only
  4430 proof states;
  4431 
  4432 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4433 additional print modes to be specified; e.g. "pr(latex)" will print
  4434 proof state according to the Isabelle LaTeX style;
  4435 
  4436 * Isar: improved support for emulating tactic scripts, including proof
  4437 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4438 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4439 (for HOL datatypes);
  4440 
  4441 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4442 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4443 'proof method scripts' have to be in depth-first order;
  4444 
  4445 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4446 
  4447 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4448 should instead use individual commands for printing items
  4449 (print_commands, print_methods etc.);
  4450 
  4451 * Isar: added 'nothing' --- the empty list of theorems;
  4452 
  4453 
  4454 *** HOL ***
  4455 
  4456 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4457 corresponding virtual machine and a specification of its bytecode
  4458 verifier and a lightweight bytecode verifier, including proofs of
  4459 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4460 Cornelia Pusch (see also the homepage of project Bali at
  4461 http://isabelle.in.tum.de/Bali/);
  4462 
  4463 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4464 Clemens Ballarin;
  4465 
  4466 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4467 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4468 Rasmussen;
  4469 
  4470 * HOL/Lattice: fundamental concepts of lattice theory and order
  4471 structures, including duals, properties of bounds versus algebraic
  4472 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4473 Theorem for complete lattices etc.; may also serve as a demonstration
  4474 for abstract algebraic reasoning using axiomatic type classes, and
  4475 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4476 
  4477 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4478 von Oheimb;
  4479 
  4480 * HOL/IMPP: extension of IMP with local variables and mutually
  4481 recursive procedures, by David von Oheimb;
  4482 
  4483 * HOL/Lambda: converted into new-style theory and document;
  4484 
  4485 * HOL/ex/Multiquote: example of multiple nested quotations and
  4486 anti-quotations -- basically a generalized version of de-Bruijn
  4487 representation; very useful in avoiding lifting of operations;
  4488 
  4489 * HOL/record: added general record equality rule to simpset; fixed
  4490 select-update simplification procedure to handle extended records as
  4491 well; admit "r" as field name;
  4492 
  4493 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4494 other numeric types and also as the identity of groups, rings, etc.;
  4495 
  4496 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4497 Types nat and int belong to this axclass;
  4498 
  4499 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4500    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4501    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4502   two terms #m*u and #n*u are replaced by #(m+n)*u
  4503     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4504   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4505     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4506 
  4507 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4508 powerful prover for predicate logic but knows nothing of clasets; see
  4509 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4510 
  4511 * HOL: new version of "case_tac" subsumes both boolean case split and
  4512 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4513 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4514 
  4515 * HOL: simplification no longer dives into case-expressions: only the
  4516 selector expression is simplified, but not the remaining arms; to
  4517 enable full simplification of case-expressions for datatype t, you may
  4518 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4519 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4520 
  4521 * HOL/recdef: the recursion equations generated by 'recdef' for
  4522 function 'f' are now called f.simps instead of f.rules; if all
  4523 termination conditions are proved automatically, these simplification
  4524 rules are added to the simpset, as in primrec; rules may be named
  4525 individually as well, resulting in a separate list of theorems for
  4526 each equation;
  4527 
  4528 * HOL/While is a new theory that provides a while-combinator. It
  4529 permits the definition of tail-recursive functions without the
  4530 provision of a termination measure. The latter is necessary once the
  4531 invariant proof rule for while is applied.
  4532 
  4533 * HOL: new (overloaded) notation for the set of elements below/above
  4534 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4535 
  4536 * HOL: theorems impI, allI, ballI bound as "strip";
  4537 
  4538 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4539 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4540 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4541 
  4542 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4543 
  4544 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4545 main HOL, but was unused);
  4546 
  4547 * HOL: fewer consts declared as global (e.g. have to refer to
  4548 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4549 
  4550 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4551 in case of overlap with user translations (e.g. judgements over
  4552 tuples); (note that the underlying logical represenation is still
  4553 bogus);
  4554 
  4555 
  4556 *** ZF ***
  4557 
  4558 * ZF: simplification automatically cancels common terms in arithmetic
  4559 expressions over nat and int;
  4560 
  4561 * ZF: new treatment of nat to minimize type-checking: all operators
  4562 coerce their operands to a natural number using the function natify,
  4563 making the algebraic laws unconditional;
  4564 
  4565 * ZF: as above, for int: operators coerce their operands to an integer
  4566 using the function intify;
  4567 
  4568 * ZF: the integer library now contains many of the usual laws for the
  4569 orderings, including $<=, and monotonicity laws for $+ and $*;
  4570 
  4571 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4572 simplification;
  4573 
  4574 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4575 to the simplifier and classical reasoner simultaneously;
  4576 
  4577 
  4578 *** General ***
  4579 
  4580 * Provers: blast_tac now handles actual object-logic rules as
  4581 assumptions; note that auto_tac uses blast_tac internally as well;
  4582 
  4583 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4584 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4585 
  4586 * Provers: delrules now handles destruct rules as well (no longer need
  4587 explicit make_elim);
  4588 
  4589 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4590   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4591 use instead the strong form,
  4592   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4593 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4594 from destruct-rules;
  4595 
  4596 * Provers: Simplifier.easy_setup provides a fast path to basic
  4597 Simplifier setup for new object-logics;
  4598 
  4599 * Pure: AST translation rules no longer require constant head on LHS;
  4600 
  4601 * Pure: improved name spaces: ambiguous output is qualified; support
  4602 for hiding of names;
  4603 
  4604 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4605 XSYMBOL_HOME; no longer need to do manual configuration in most
  4606 situations;
  4607 
  4608 * system: compression of ML heaps images may now be controlled via -c
  4609 option of isabelle and isatool usedir (currently only observed by
  4610 Poly/ML);
  4611 
  4612 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4613 useful for remote X11);
  4614 
  4615 * system: provide TAGS file for Isabelle sources;
  4616 
  4617 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4618 order;
  4619 
  4620 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4621 timing flag supersedes proof_timing and Toplevel.trace;
  4622 
  4623 * ML: new combinators |>> and |>>> for incremental transformations
  4624 with secondary results (e.g. certain theory extensions):
  4625 
  4626 * ML: PureThy.add_defs gets additional argument to indicate potential
  4627 overloading (usually false);
  4628 
  4629 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4630 results;
  4631 
  4632 
  4633 
  4634 New in Isabelle99 (October 1999)
  4635 --------------------------------
  4636 
  4637 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4638 
  4639 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4640 are no longer simplified.  (This allows the simplifier to unfold recursive
  4641 functional programs.)  To restore the old behaviour, declare
  4642 
  4643     Delcongs [if_weak_cong];
  4644 
  4645 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4646 complement;
  4647 
  4648 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4649 
  4650 * HOL/datatype: mutual_induct_tac no longer exists --
  4651   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4652 
  4653 * HOL/typedef: fixed type inference for representing set; type
  4654 arguments now have to occur explicitly on the rhs as type constraints;
  4655 
  4656 * ZF: The con_defs part of an inductive definition may no longer refer
  4657 to constants declared in the same theory;
  4658 
  4659 * HOL, ZF: the function mk_cases, generated by the inductive
  4660 definition package, has lost an argument.  To simplify its result, it
  4661 uses the default simpset instead of a supplied list of theorems.
  4662 
  4663 * HOL/List: the constructors of type list are now Nil and Cons;
  4664 
  4665 * Simplifier: the type of the infix ML functions
  4666         setSSolver addSSolver setSolver addSolver
  4667 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4668 for packaging solvers. A solver is created via
  4669         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4670 where the string argument is only a comment.
  4671 
  4672 
  4673 *** Proof tools ***
  4674 
  4675 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4676 decision procedure for linear arithmetic. Currently it is used for
  4677 types `nat', `int', and `real' in HOL (see below); it can, should and
  4678 will be instantiated for other types and logics as well.
  4679 
  4680 * The simplifier now accepts rewrite rules with flexible heads, eg
  4681      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4682   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4683   matching.
  4684 
  4685 
  4686 *** General ***
  4687 
  4688 * New Isabelle/Isar subsystem provides an alternative to traditional
  4689 tactical theorem proving; together with the ProofGeneral/isar user
  4690 interface it offers an interactive environment for developing human
  4691 readable proof documents (Isar == Intelligible semi-automated
  4692 reasoning); for further information see isatool doc isar-ref,
  4693 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4694 
  4695 * improved and simplified presentation of theories: better HTML markup
  4696 (including colors), graph views in several sizes; isatool usedir now
  4697 provides a proper interface for user theories (via -P option); actual
  4698 document preparation based on (PDF)LaTeX is available as well (for
  4699 new-style theories only); see isatool doc system for more information;
  4700 
  4701 * native support for Proof General, both for classic Isabelle and
  4702 Isabelle/Isar;
  4703 
  4704 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4705 using the graph browser tool;
  4706 
  4707 * Isabelle manuals now also available as PDF;
  4708 
  4709 * theory loader rewritten from scratch (may not be fully
  4710 bug-compatible); old loadpath variable has been replaced by show_path,
  4711 add_path, del_path, reset_path functions; new operations such as
  4712 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4713 isatool doc ref);
  4714 
  4715 * improved isatool install: option -k creates KDE application icon,
  4716 option -p DIR installs standalone binaries;
  4717 
  4718 * added ML_PLATFORM setting (useful for cross-platform installations);
  4719 more robust handling of platform specific ML images for SML/NJ;
  4720 
  4721 * the settings environment is now statically scoped, i.e. it is never
  4722 created again in sub-processes invoked from isabelle, isatool, or
  4723 Isabelle;
  4724 
  4725 * path element specification '~~' refers to '$ISABELLE_HOME';
  4726 
  4727 * in locales, the "assumes" and "defines" parts may be omitted if
  4728 empty;
  4729 
  4730 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4731 long arrows);
  4732 
  4733 * new print_mode "HTML";
  4734 
  4735 * new flag show_tags controls display of tags of theorems (which are
  4736 basically just comments that may be attached by some tools);
  4737 
  4738 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4739 mode and goal output format:
  4740 
  4741 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4742 244c244
  4743 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4744 ---
  4745 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4746 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4747 181c181
  4748 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4749 ---
  4750 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4751 
  4752 * function bind_thms stores lists of theorems (cf. bind_thm);
  4753 
  4754 * new shorthand tactics ftac, eatac, datac, fatac;
  4755 
  4756 * qed (and friends) now accept "" as result name; in that case the
  4757 theorem is not stored, but proper checks and presentation of the
  4758 result still apply;
  4759 
  4760 * theorem database now also indexes constants "Trueprop", "all",
  4761 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4762 
  4763 
  4764 *** HOL ***
  4765 
  4766 ** HOL arithmetic **
  4767 
  4768 * There are now decision procedures for linear arithmetic over nat and
  4769 int:
  4770 
  4771 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4772 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4773 are treated as atomic; subformulae not involving type `nat' or `int'
  4774 are ignored; quantified subformulae are ignored unless they are
  4775 positive universal or negative existential. The tactic has to be
  4776 invoked by hand and can be a little bit slow. In particular, the
  4777 running time is exponential in the number of occurrences of `min' and
  4778 `max', and `-' on `nat'.
  4779 
  4780 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4781 (negated) (in)equalities among the premises and the conclusion into
  4782 account (i.e. no compound formulae) and does not know about `min' and
  4783 `max', and `-' on `nat'. It is fast and is used automatically by the
  4784 simplifier.
  4785 
  4786 NB: At the moment, these decision procedures do not cope with mixed
  4787 nat/int formulae where the two parts interact, such as `m < n ==>
  4788 int(m) < int(n)'.
  4789 
  4790 * HOL/Numeral provides a generic theory of numerals (encoded
  4791 efficiently as bit strings); setup for types nat/int/real is in place;
  4792 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4793 int, existing theories and proof scripts may require a few additional
  4794 type constraints;
  4795 
  4796 * integer division and remainder can now be performed on constant
  4797 arguments;
  4798 
  4799 * many properties of integer multiplication, division and remainder
  4800 are now available;
  4801 
  4802 * An interface to the Stanford Validity Checker (SVC) is available through the
  4803 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4804 are proved automatically.  SVC must be installed separately, and its results
  4805 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4806 invocation of the underlying oracle).  For SVC see
  4807   http://verify.stanford.edu/SVC
  4808 
  4809 * IsaMakefile: the HOL-Real target now builds an actual image;
  4810 
  4811 
  4812 ** HOL misc **
  4813 
  4814 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4815 (in Isabelle/Isar) -- by Gertrud Bauer;
  4816 
  4817 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4818 analysis for assembly languages with subtypes;
  4819 
  4820 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4821 -- avoids syntactic ambiguities and treats state, transition, and
  4822 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4823 changed syntax and (many) tactics;
  4824 
  4825 * HOL/inductive: Now also handles more general introduction rules such
  4826   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4827   theorems are now maintained within the theory (maintained via the
  4828   "mono" attribute);
  4829 
  4830 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4831   (using function types) such as
  4832 
  4833   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4834 
  4835 * HOL/record: record_simproc (part of the default simpset) takes care
  4836 of selectors applied to updated records; record_split_tac is no longer
  4837 part of the default claset; update_defs may now be removed from the
  4838 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4839 
  4840   claset_ref () := claset() addSWrapper record_split_wrapper;
  4841   Delsimprocs [record_simproc]
  4842 
  4843 * HOL/typedef: fixed type inference for representing set; type
  4844 arguments now have to occur explicitly on the rhs as type constraints;
  4845 
  4846 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4847 names rather than an ML expression;
  4848 
  4849 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4850 supplied later.  Program schemes can be defined, such as
  4851     "While B C s = (if B s then While B C (C s) else s)"
  4852 where the well-founded relation can be chosen after B and C have been given.
  4853 
  4854 * HOL/List: the constructors of type list are now Nil and Cons;
  4855 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4856 course, ML tools referring to List.list.op # etc. have to be adapted;
  4857 
  4858 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4859 disabled by default; run isabelle with option -m HOL to get back to
  4860 the original Gordon/HOL-style output;
  4861 
  4862 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4863 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4864 
  4865 * HOL basic syntax simplified (more orthogonal): all variants of
  4866 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4867 Eps operator is provided as well: "SOME x. P[x]";
  4868 
  4869 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4870 
  4871 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4872 thus available for user theories;
  4873 
  4874 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4875 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4876 time;
  4877 
  4878 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4879 several times and then mp;
  4880 
  4881 
  4882 *** LK ***
  4883 
  4884 * the notation <<...>> is now available as a notation for sequences of
  4885 formulas;
  4886 
  4887 * the simplifier is now installed
  4888 
  4889 * the axiom system has been generalized (thanks to Soren Heilmann)
  4890 
  4891 * the classical reasoner now has a default rule database
  4892 
  4893 
  4894 *** ZF ***
  4895 
  4896 * new primrec section allows primitive recursive functions to be given
  4897 directly (as in HOL) over datatypes and the natural numbers;
  4898 
  4899 * new tactics induct_tac and exhaust_tac for induction (or case
  4900 analysis) over datatypes and the natural numbers;
  4901 
  4902 * the datatype declaration of type T now defines the recursor T_rec;
  4903 
  4904 * simplification automatically does freeness reasoning for datatype
  4905 constructors;
  4906 
  4907 * automatic type-inference, with AddTCs command to insert new
  4908 type-checking rules;
  4909 
  4910 * datatype introduction rules are now added as Safe Introduction rules
  4911 to the claset;
  4912 
  4913 * the syntax "if P then x else y" is now available in addition to
  4914 if(P,x,y);
  4915 
  4916 
  4917 *** Internal programming interfaces ***
  4918 
  4919 * tuned simplifier trace output; new flag debug_simp;
  4920 
  4921 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4922 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4923 
  4924 * AxClass.axclass_tac lost the theory argument;
  4925 
  4926 * tuned current_goals_markers semantics: begin / end goal avoids
  4927 printing empty lines;
  4928 
  4929 * removed prs and prs_fn hook, which was broken because it did not
  4930 include \n in its semantics, forcing writeln to add one
  4931 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4932 string -> unit if you really want to output text without newline;
  4933 
  4934 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4935 plain output, interface builders may have to enable 'isabelle_font'
  4936 mode to get Isabelle font glyphs as before;
  4937 
  4938 * refined token_translation interface; INCOMPATIBILITY: output length
  4939 now of type real instead of int;
  4940 
  4941 * theory loader actions may be traced via new ThyInfo.add_hook
  4942 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4943 your own database of information attached to *whole* theories -- as
  4944 opposed to intra-theory data slots offered via TheoryDataFun;
  4945 
  4946 * proper handling of dangling sort hypotheses (at last!);
  4947 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4948 extra sort hypotheses that can be witnessed from the type signature;
  4949 the force_strip_shyps flag is gone, any remaining shyps are simply
  4950 left in the theorem (with a warning issued by strip_shyps_warning);
  4951 
  4952 
  4953 
  4954 New in Isabelle98-1 (October 1998)
  4955 ----------------------------------
  4956 
  4957 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4958 
  4959 * several changes of automated proof tools;
  4960 
  4961 * HOL: major changes to the inductive and datatype packages, including
  4962 some minor incompatibilities of theory syntax;
  4963 
  4964 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4965 called `inj_on';
  4966 
  4967 * HOL: removed duplicate thms in Arith:
  4968   less_imp_add_less  should be replaced by  trans_less_add1
  4969   le_imp_add_le      should be replaced by  trans_le_add1
  4970 
  4971 * HOL: unary minus is now overloaded (new type constraints may be
  4972 required);
  4973 
  4974 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4975 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4976 now taken as an integer constant.
  4977 
  4978 * Pure: ML function 'theory_of' renamed to 'theory';
  4979 
  4980 
  4981 *** Proof tools ***
  4982 
  4983 * Simplifier:
  4984   1. Asm_full_simp_tac is now more aggressive.
  4985      1. It will sometimes reorient premises if that increases their power to
  4986         simplify.
  4987      2. It does no longer proceed strictly from left to right but may also
  4988         rotate premises to achieve further simplification.
  4989      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4990      old Asm_full_simp_tac in that it does not rotate premises.
  4991   2. The simplifier now knows a little bit about nat-arithmetic.
  4992 
  4993 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4994 allows for selected deletion of wrappers, by introduction of names for
  4995 wrapper functionals.  This implies that addbefore, addSbefore,
  4996 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4997 and that adding two tactics with the same name overwrites the first
  4998 one (emitting a warning).
  4999   type wrapper = (int -> tactic) -> (int -> tactic)
  5000   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5001   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5002   delWrapper, delSWrapper: claset *  string            -> claset
  5003   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5004 
  5005 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5006 semantics; addbefore now affects only the unsafe part of step_tac
  5007 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5008 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5009 by Force_tac;
  5010 
  5011 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5012 compWrapper; added safe wrapper (and access functions for it);
  5013 
  5014 * HOL/split_all_tac is now much faster and fails if there is nothing
  5015 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5016 and the names of the automatically generated variables have changed.
  5017 split_all_tac has moved within claset() from unsafe wrappers to safe
  5018 wrappers, which means that !!-bound variables are split much more
  5019 aggressively, and safe_tac and clarify_tac now split such variables.
  5020 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5021 Note: the same holds for record_split_tac, which does the job of
  5022 split_all_tac for record fields.
  5023 
  5024 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5025 permanently to the default simpset using Addsplits just like
  5026 Addsimps. They can be removed via Delsplits just like
  5027 Delsimps. Lower-case versions are also available.
  5028 
  5029 * HOL/Simplifier: The rule split_if is now part of the default
  5030 simpset. This means that the simplifier will eliminate all occurrences
  5031 of if-then-else in the conclusion of a goal. To prevent this, you can
  5032 either remove split_if completely from the default simpset by
  5033 `Delsplits [split_if]' or remove it in a specific call of the
  5034 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5035 other case splitting rules to/from the default simpset: every datatype
  5036 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5037 t is the name of the datatype).
  5038 
  5039 * Classical reasoner / Simplifier combination: new force_tac (and
  5040 derivatives Force_tac, force) combines rewriting and classical
  5041 reasoning (and whatever other tools) similarly to auto_tac, but is
  5042 aimed to solve the given subgoal completely.
  5043 
  5044 
  5045 *** General ***
  5046 
  5047 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5048 and `goalw': the theory is no longer needed as an explicit argument -
  5049 the current theory context is used; assumptions are no longer returned
  5050 at the ML-level unless one of them starts with ==> or !!; it is
  5051 recommended to convert to these new commands using isatool fixgoal
  5052 (backup your sources first!);
  5053 
  5054 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5055 the current theory context, and 'theory' to lookup stored theories;
  5056 
  5057 * new theory section 'locale' for declaring constants, assumptions and
  5058 definitions that have local scope;
  5059 
  5060 * new theory section 'nonterminals' for purely syntactic types;
  5061 
  5062 * new theory section 'setup' for generic ML setup functions
  5063 (e.g. package initialization);
  5064 
  5065 * the distribution now includes Isabelle icons: see
  5066 lib/logo/isabelle-{small,tiny}.xpm;
  5067 
  5068 * isatool install - install binaries with absolute references to
  5069 ISABELLE_HOME/bin;
  5070 
  5071 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5072 
  5073 * print mode 'emacs' reserved for Isamode;
  5074 
  5075 * support multiple print (ast) translations per constant name;
  5076 
  5077 * theorems involving oracles are now printed with a suffixed [!];
  5078 
  5079 
  5080 *** HOL ***
  5081 
  5082 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5083 
  5084 * HOL/inductive package reorganized and improved: now supports mutual
  5085 definitions such as
  5086 
  5087   inductive EVEN ODD
  5088     intrs
  5089       null "0 : EVEN"
  5090       oddI "n : EVEN ==> Suc n : ODD"
  5091       evenI "n : ODD ==> Suc n : EVEN"
  5092 
  5093 new theorem list "elims" contains an elimination rule for each of the
  5094 recursive sets; inductive definitions now handle disjunctive premises
  5095 correctly (also ZF);
  5096 
  5097 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5098 "mutual_induct" no longer exists - the induction rule is always
  5099 contained in "induct";
  5100 
  5101 
  5102 * HOL/datatype package re-implemented and greatly improved: now
  5103 supports mutually recursive datatypes such as
  5104 
  5105   datatype
  5106     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5107             | SUM ('a aexp) ('a aexp)
  5108             | DIFF ('a aexp) ('a aexp)
  5109             | NUM 'a
  5110   and
  5111     'a bexp = LESS ('a aexp) ('a aexp)
  5112             | AND ('a bexp) ('a bexp)
  5113             | OR ('a bexp) ('a bexp)
  5114 
  5115 as well as indirectly recursive datatypes such as
  5116 
  5117   datatype
  5118     ('a, 'b) term = Var 'a
  5119                   | App 'b ((('a, 'b) term) list)
  5120 
  5121 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5122 induction on mutually / indirectly recursive datatypes.
  5123 
  5124 Primrec equations are now stored in theory and can be accessed via
  5125 <function_name>.simps.
  5126 
  5127 INCOMPATIBILITIES:
  5128 
  5129   - Theories using datatypes must now have theory Datatype as an
  5130     ancestor.
  5131   - The specific <typename>.induct_tac no longer exists - use the
  5132     generic induct_tac instead.
  5133   - natE has been renamed to nat.exhaust - use exhaust_tac
  5134     instead of res_inst_tac ... natE. Note that the variable
  5135     names in nat.exhaust differ from the names in natE, this
  5136     may cause some "fragile" proofs to fail.
  5137   - The theorems split_<typename>_case and split_<typename>_case_asm
  5138     have been renamed to <typename>.split and <typename>.split_asm.
  5139   - Since default sorts of type variables are now handled correctly,
  5140     some datatype definitions may have to be annotated with explicit
  5141     sort constraints.
  5142   - Primrec definitions no longer require function name and type
  5143     of recursive argument.
  5144 
  5145 Consider using isatool fixdatatype to adapt your theories and proof
  5146 scripts to the new package (backup your sources first!).
  5147 
  5148 
  5149 * HOL/record package: considerably improved implementation; now
  5150 includes concrete syntax for record types, terms, updates; theorems
  5151 for surjective pairing and splitting !!-bound record variables; proof
  5152 support is as follows:
  5153 
  5154   1) standard conversions (selectors or updates applied to record
  5155 constructor terms) are part of the standard simpset;
  5156 
  5157   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5158 made part of standard simpset and claset via addIffs;
  5159 
  5160   3) a tactic for record field splitting (record_split_tac) is part of
  5161 the standard claset (addSWrapper);
  5162 
  5163 To get a better idea about these rules you may retrieve them via
  5164 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5165 the name of your record type.
  5166 
  5167 The split tactic 3) conceptually simplifies by the following rule:
  5168 
  5169   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5170 
  5171 Thus any record variable that is bound by meta-all will automatically
  5172 blow up into some record constructor term, consequently the
  5173 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5174 solve record problems automatically.
  5175 
  5176 
  5177 * reorganized the main HOL image: HOL/Integ and String loaded by
  5178 default; theory Main includes everything;
  5179 
  5180 * automatic simplification of integer sums and comparisons, using cancellation;
  5181 
  5182 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5183 
  5184 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5185 
  5186 * many new identities for unions, intersections, set difference, etc.;
  5187 
  5188 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5189 called split_if, split_split, split_sum_case and split_nat_case (to go
  5190 with add/delsplits);
  5191 
  5192 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5193 (?x::unit) = (); this is made part of the default simpset, which COULD
  5194 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5195 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5196 unit_abs_eta_conv is added in order to counter the effect of
  5197 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5198 %u.f();
  5199 
  5200 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5201 makes more sense);
  5202 
  5203 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5204   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5205   disjointness reasoning but breaking a few old proofs.
  5206 
  5207 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5208 to 'converse' from 'inverse' (for compatibility with ZF and some
  5209 literature);
  5210 
  5211 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5212 the well-founded relation;
  5213 
  5214 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5215     Compl A.  The "Compl" syntax remains available as input syntax for this
  5216     release ONLY.
  5217 
  5218 * HOL/Update: new theory of function updates:
  5219     f(a:=b) == %x. if x=a then b else f x
  5220 may also be iterated as in f(a:=b,c:=d,...);
  5221 
  5222 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5223 
  5224 * HOL/List:
  5225   - new function list_update written xs[i:=v] that updates the i-th
  5226     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5227   - new function `upt' written [i..j(] which generates the list
  5228     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5229     bound write [i..j], which is a shorthand for [i..j+1(].
  5230   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5231 
  5232 * HOL/Arith:
  5233   - removed 'pred' (predecessor) function;
  5234   - generalized some theorems about n-1;
  5235   - many new laws about "div" and "mod";
  5236   - new laws about greatest common divisors (see theory ex/Primes);
  5237 
  5238 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5239 instead of "inverse";
  5240 
  5241 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5242   of the multiset ordering;
  5243 
  5244 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5245   (not included by default);
  5246 
  5247 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5248 
  5249 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5250   programs, i.e. different program variables may have different types.
  5251 
  5252 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5253   [previously, this check worked only if the rewrite rule was unconditional]
  5254   Now rew can involve either definitions or equalities (either == or =).
  5255 
  5256 
  5257 *** ZF ***
  5258 
  5259 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5260   only the theorems proved on ZF.ML;
  5261 
  5262 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5263   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5264   disjointness reasoning but breaking a few old proofs.
  5265 
  5266 * ZF/Update: new theory of function updates
  5267     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5268   may also be iterated as in f(a:=b,c:=d,...);
  5269 
  5270 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5271 
  5272 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5273   [previously, this check worked only if the rewrite rule was unconditional]
  5274   Now rew can involve either definitions or equalities (either == or =).
  5275 
  5276 * case_tac provided for compatibility with HOL
  5277     (like the old excluded_middle_tac, but with subgoals swapped)
  5278 
  5279 
  5280 *** Internal programming interfaces ***
  5281 
  5282 * Pure: several new basic modules made available for general use, see
  5283 also src/Pure/README;
  5284 
  5285 * improved the theory data mechanism to support encapsulation (data
  5286 kind name replaced by private Object.kind, acting as authorization
  5287 key); new type-safe user interface via functor TheoryDataFun; generic
  5288 print_data function becomes basically useless;
  5289 
  5290 * removed global_names compatibility flag -- all theory declarations
  5291 are qualified by default;
  5292 
  5293 * module Pure/Syntax now offers quote / antiquote translation
  5294 functions (useful for Hoare logic etc. with implicit dependencies);
  5295 see HOL/ex/Antiquote for an example use;
  5296 
  5297 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5298 cterm -> thm;
  5299 
  5300 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5301 subgoal;
  5302 
  5303 * Display.print_goals function moved to Locale.print_goals;
  5304 
  5305 * standard print function for goals supports current_goals_markers
  5306 variable for marking begin of proof, end of proof, start of goal; the
  5307 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5308 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5309 for example;
  5310 
  5311 
  5312 
  5313 New in Isabelle98 (January 1998)
  5314 --------------------------------
  5315 
  5316 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5317 
  5318 * changed lexical syntax of terms / types: dots made part of long
  5319 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5320 
  5321 * simpset (and claset) reference variable replaced by functions
  5322 simpset / simpset_ref;
  5323 
  5324 * no longer supports theory aliases (via merge) and non-trivial
  5325 implicit merge of thms' signatures;
  5326 
  5327 * most internal names of constants changed due to qualified names;
  5328 
  5329 * changed Pure/Sequence interface (see Pure/seq.ML);
  5330 
  5331 
  5332 *** General Changes ***
  5333 
  5334 * hierachically structured name spaces (for consts, types, axms, thms
  5335 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5336 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5337 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5338 long_names for fully qualified output names; NOTE: ML programs
  5339 (special tactics, packages etc.) referring to internal names may have
  5340 to be adapted to cope with fully qualified names; in case of severe
  5341 backward campatibility problems try setting 'global_names' at compile
  5342 time to have enrything declared within a flat name space; one may also
  5343 fine tune name declarations in theories via the 'global' and 'local'
  5344 section;
  5345 
  5346 * reimplemented the implicit simpset and claset using the new anytype
  5347 data filed in signatures; references simpset:simpset ref etc. are
  5348 replaced by functions simpset:unit->simpset and
  5349 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5350 to patch your ML files accordingly;
  5351 
  5352 * HTML output now includes theory graph data for display with Java
  5353 applet or isatool browser; data generated automatically via isatool
  5354 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5355 
  5356 * defs may now be conditional; improved rewrite_goals_tac to handle
  5357 conditional equations;
  5358 
  5359 * defs now admits additional type arguments, using TYPE('a) syntax;
  5360 
  5361 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5362 creates a new theory node; implicit merge of thms' signatures is
  5363 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5364 transfer:theory->thm->thm in (rare) cases;
  5365 
  5366 * improved handling of draft signatures / theories; draft thms (and
  5367 ctyps, cterms) are automatically promoted to real ones;
  5368 
  5369 * slightly changed interfaces for oracles: admit many per theory, named
  5370 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5371 
  5372 * print_goals: optional output of const types (set show_consts and
  5373 show_types);
  5374 
  5375 * improved output of warnings (###) and errors (***);
  5376 
  5377 * subgoal_tac displays a warning if the new subgoal has type variables;
  5378 
  5379 * removed old README and Makefiles;
  5380 
  5381 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5382 
  5383 * removed obsolete init_pps and init_database;
  5384 
  5385 * deleted the obsolete tactical STATE, which was declared by
  5386     fun STATE tacfun st = tacfun st st;
  5387 
  5388 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5389 (which abbreviates $HOME);
  5390 
  5391 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5392 use isatool fixseq to adapt your ML programs (this works for fully
  5393 qualified references to the Sequence structure only!);
  5394 
  5395 * use_thy no longer requires writable current directory; it always
  5396 reloads .ML *and* .thy file, if either one is out of date;
  5397 
  5398 
  5399 *** Classical Reasoner ***
  5400 
  5401 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5402 tactics that use classical reasoning to simplify a subgoal without
  5403 splitting it into several subgoals;
  5404 
  5405 * Safe_tac: like safe_tac but uses the default claset;
  5406 
  5407 
  5408 *** Simplifier ***
  5409 
  5410 * added simplification meta rules:
  5411     (asm_)(full_)simplify: simpset -> thm -> thm;
  5412 
  5413 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5414 logics (again);
  5415 
  5416 * added prems argument to simplification procedures;
  5417 
  5418 * HOL, FOL, ZF: added infix function `addsplits':
  5419   instead of `<simpset> setloop (split_tac <thms>)'
  5420   you can simply write `<simpset> addsplits <thms>'
  5421 
  5422 
  5423 *** Syntax ***
  5424 
  5425 * TYPE('a) syntax for type reflection terms;
  5426 
  5427 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5428 
  5429 * pretty printer: changed order of mixfix annotation preference (again!);
  5430 
  5431 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5432 
  5433 
  5434 *** HOL ***
  5435 
  5436 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5437   with `addloop' of the simplifier to faciliate case splitting in premises.
  5438 
  5439 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5440 
  5441 * HOL/Auth: new protocol proofs including some for the Internet
  5442   protocol TLS;
  5443 
  5444 * HOL/Map: new theory of `maps' a la VDM;
  5445 
  5446 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5447 cancelling out common nat summands from =, <, <= (in)equalities, or
  5448 differences; simplification procedures nat_cancel_factor for
  5449 cancelling common factor from =, <, <= (in)equalities over natural
  5450 sums; nat_cancel contains both kinds of procedures, it is installed by
  5451 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5452 
  5453 * HOL/simplifier: terms of the form
  5454   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5455   are rewritten to
  5456   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5457   and those of the form
  5458   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5459   are rewritten to
  5460   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5461 
  5462 * HOL/datatype
  5463   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5464 
  5465   P(t_case f1 ... fn x) =
  5466      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5467         ...
  5468        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5469      )
  5470 
  5471   and a theorem `split_t_case_asm' of the form
  5472 
  5473   P(t_case f1 ... fn x) =
  5474     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5475         ...
  5476        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5477      )
  5478   which can be added to a simpset via `addsplits'. The existing theorems
  5479   expand_list_case and expand_option_case have been renamed to
  5480   split_list_case and split_option_case.
  5481 
  5482 * HOL/Arithmetic:
  5483   - `pred n' is automatically converted to `n-1'.
  5484     Users are strongly encouraged not to use `pred' any longer,
  5485     because it will disappear altogether at some point.
  5486   - Users are strongly encouraged to write "0 < n" rather than
  5487     "n ~= 0". Theorems and proof tools have been modified towards this
  5488     `standard'.
  5489 
  5490 * HOL/Lists:
  5491   the function "set_of_list" has been renamed "set" (and its theorems too);
  5492   the function "nth" now takes its arguments in the reverse order and
  5493   has acquired the infix notation "!" as in "xs!n".
  5494 
  5495 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5496 
  5497 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5498   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5499 
  5500 * HOL/record: extensible records with schematic structural subtyping
  5501 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5502 still lacks various theorems and concrete record syntax;
  5503 
  5504 
  5505 *** HOLCF ***
  5506 
  5507 * removed "axioms" and "generated by" sections;
  5508 
  5509 * replaced "ops" section by extended "consts" section, which is capable of
  5510   handling the continuous function space "->" directly;
  5511 
  5512 * domain package:
  5513   . proves theorems immediately and stores them in the theory,
  5514   . creates hierachical name space,
  5515   . now uses normal mixfix annotations (instead of cinfix...),
  5516   . minor changes to some names and values (for consistency),
  5517   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5518   . separator between mutual domain defs: changed "," to "and",
  5519   . improved handling of sort constraints;  now they have to
  5520     appear on the left-hand side of the equations only;
  5521 
  5522 * fixed LAM <x,y,zs>.b syntax;
  5523 
  5524 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5525 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5526 
  5527 
  5528 *** FOL and ZF ***
  5529 
  5530 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5531   with `addloop' of the simplifier to faciliate case splitting in premises.
  5532 
  5533 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5534 in HOL, they strip ALL and --> from proved theorems;
  5535 
  5536 
  5537 
  5538 New in Isabelle94-8 (May 1997)
  5539 ------------------------------
  5540 
  5541 *** General Changes ***
  5542 
  5543 * new utilities to build / run / maintain Isabelle etc. (in parts
  5544 still somewhat experimental); old Makefiles etc. still functional;
  5545 
  5546 * new 'Isabelle System Manual';
  5547 
  5548 * INSTALL text, together with ./configure and ./build scripts;
  5549 
  5550 * reimplemented type inference for greater efficiency, better error
  5551 messages and clean internal interface;
  5552 
  5553 * prlim command for dealing with lots of subgoals (an easier way of
  5554 setting goals_limit);
  5555 
  5556 
  5557 *** Syntax ***
  5558 
  5559 * supports alternative (named) syntax tables (parser and pretty
  5560 printer); internal interface is provided by add_modesyntax(_i);
  5561 
  5562 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5563 be used in conjunction with the Isabelle symbol font; uses the
  5564 "symbols" syntax table;
  5565 
  5566 * added token_translation interface (may translate name tokens in
  5567 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5568 the current print_mode); IMPORTANT: user print translation functions
  5569 are responsible for marking newly introduced bounds
  5570 (Syntax.mark_boundT);
  5571 
  5572 * token translations for modes "xterm" and "xterm_color" that display
  5573 names in bold, underline etc. or colors (which requires a color
  5574 version of xterm);
  5575 
  5576 * infixes may now be declared with names independent of their syntax;
  5577 
  5578 * added typed_print_translation (like print_translation, but may
  5579 access type of constant);
  5580 
  5581 
  5582 *** Classical Reasoner ***
  5583 
  5584 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5585 some limitations.  Blast_tac...
  5586   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5587   + ignores elimination rules that don't have the correct format
  5588         (the conclusion MUST be a formula variable)
  5589   + ignores types, which can make HOL proofs fail
  5590   + rules must not require higher-order unification, e.g. apply_type in ZF
  5591     [message "Function Var's argument not a bound variable" relates to this]
  5592   + its proof strategy is more general but can actually be slower
  5593 
  5594 * substitution with equality assumptions no longer permutes other
  5595 assumptions;
  5596 
  5597 * minor changes in semantics of addafter (now called addaltern); renamed
  5598 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5599 (and access functions for it);
  5600 
  5601 * improved combination of classical reasoner and simplifier:
  5602   + functions for handling clasimpsets
  5603   + improvement of addss: now the simplifier is called _after_ the
  5604     safe steps.
  5605   + safe variant of addss called addSss: uses safe simplifications
  5606     _during_ the safe steps. It is more complete as it allows multiple
  5607     instantiations of unknowns (e.g. with slow_tac).
  5608 
  5609 *** Simplifier ***
  5610 
  5611 * added interface for simplification procedures (functions that
  5612 produce *proven* rewrite rules on the fly, depending on current
  5613 redex);
  5614 
  5615 * ordering on terms as parameter (used for ordered rewriting);
  5616 
  5617 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5618 
  5619 * the solver is now split into a safe and an unsafe part.
  5620 This should be invisible for the normal user, except that the
  5621 functions setsolver and addsolver have been renamed to setSolver and
  5622 addSolver; added safe_asm_full_simp_tac;
  5623 
  5624 
  5625 *** HOL ***
  5626 
  5627 * a generic induction tactic `induct_tac' which works for all datatypes and
  5628 also for type `nat';
  5629 
  5630 * a generic case distinction tactic `exhaust_tac' which works for all
  5631 datatypes and also for type `nat';
  5632 
  5633 * each datatype comes with a function `size';
  5634 
  5635 * patterns in case expressions allow tuple patterns as arguments to
  5636 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5637 
  5638 * primrec now also works with type nat;
  5639 
  5640 * recdef: a new declaration form, allows general recursive functions to be
  5641 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5642 
  5643 * the constant for negation has been renamed from "not" to "Not" to
  5644 harmonize with FOL, ZF, LK, etc.;
  5645 
  5646 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5647 infinite lists;
  5648 
  5649 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5650 
  5651 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5652 problems in commutative rings, using axiomatic type classes for + and *;
  5653 
  5654 * more examples in HOL/MiniML and HOL/Auth;
  5655 
  5656 * more default rewrite rules for quantifiers, union/intersection;
  5657 
  5658 * a new constant `arbitrary == @x.False';
  5659 
  5660 * HOLCF/IOA replaces old HOL/IOA;
  5661 
  5662 * HOLCF changes: derived all rules and arities
  5663   + axiomatic type classes instead of classes
  5664   + typedef instead of faking type definitions
  5665   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5666   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5667   + eliminated the types void, one, tr
  5668   + use unit lift and bool lift (with translations) instead of one and tr
  5669   + eliminated blift from Lift3.thy (use Def instead of blift)
  5670   all eliminated rules are derived as theorems --> no visible changes ;
  5671 
  5672 
  5673 *** ZF ***
  5674 
  5675 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5676 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5677 as ZF_cs addSIs [equalityI];
  5678 
  5679 
  5680 
  5681 New in Isabelle94-7 (November 96)
  5682 ---------------------------------
  5683 
  5684 * allowing negative levels (as offsets) in prlev and choplev;
  5685 
  5686 * super-linear speedup for large simplifications;
  5687 
  5688 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5689 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5690 FAIL); can suppress it using the command Delsimps (ex_simps @
  5691 all_simps); De Morgan laws are also now included, by default;
  5692 
  5693 * improved printing of ==>  :  ~:
  5694 
  5695 * new object-logic "Sequents" adds linear logic, while replacing LK
  5696 and Modal (thanks to Sara Kalvala);
  5697 
  5698 * HOL/Auth: correctness proofs for authentication protocols;
  5699 
  5700 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5701 examples on HOL/Auth);
  5702 
  5703 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5704 the rewriter and classical reasoner simultaneously;
  5705 
  5706 * function uresult no longer returns theorems in "standard" format;
  5707 regain previous version by: val uresult = standard o uresult;
  5708 
  5709 
  5710 
  5711 New in Isabelle94-6
  5712 -------------------
  5713 
  5714 * oracles -- these establish an interface between Isabelle and trusted
  5715 external reasoners, which may deliver results as theorems;
  5716 
  5717 * proof objects (in particular record all uses of oracles);
  5718 
  5719 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5720 
  5721 * "constdefs" section in theory files;
  5722 
  5723 * "primrec" section (HOL) no longer requires names;
  5724 
  5725 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5726 
  5727 
  5728 
  5729 New in Isabelle94-5
  5730 -------------------
  5731 
  5732 * reduced space requirements;
  5733 
  5734 * automatic HTML generation from theories;
  5735 
  5736 * theory files no longer require "..." (quotes) around most types;
  5737 
  5738 * new examples, including two proofs of the Church-Rosser theorem;
  5739 
  5740 * non-curried (1994) version of HOL is no longer distributed;
  5741 
  5742 
  5743 
  5744 New in Isabelle94-4
  5745 -------------------
  5746 
  5747 * greatly reduced space requirements;
  5748 
  5749 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5750 
  5751 * searchable theorem database (see the section "Retrieving theorems" on
  5752 page 8 of the Reference Manual);
  5753 
  5754 * new examples, including Grabczewski's monumental case study of the
  5755 Axiom of Choice;
  5756 
  5757 * The previous version of HOL renamed to Old_HOL;
  5758 
  5759 * The new version of HOL (previously called CHOL) uses a curried syntax
  5760 for functions.  Application looks like f a b instead of f(a,b);
  5761 
  5762 * Mutually recursive inductive definitions finally work in HOL;
  5763 
  5764 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5765 translates to the operator "split";
  5766 
  5767 
  5768 
  5769 New in Isabelle94-3
  5770 -------------------
  5771 
  5772 * new infix operator, addss, allowing the classical reasoner to
  5773 perform simplification at each step of its search.  Example:
  5774         fast_tac (cs addss ss)
  5775 
  5776 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5777 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5778 look like (a,b) instead of <a,b>;
  5779 
  5780 * PLEASE NOTE: CHOL will eventually replace HOL!
  5781 
  5782 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5783 It translates to the operator "split".  A new theory of integers is available;
  5784 
  5785 * In ZF, integer numerals now denote two's-complement binary integers.
  5786 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5787 
  5788 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5789 of the Axiom of Choice;
  5790 
  5791 
  5792 
  5793 New in Isabelle94-2
  5794 -------------------
  5795 
  5796 * Significantly faster resolution;
  5797 
  5798 * the different sections in a .thy file can now be mixed and repeated
  5799 freely;
  5800 
  5801 * Database of theorems for FOL, HOL and ZF.  New
  5802 commands including qed, qed_goal and bind_thm store theorems in the database.
  5803 
  5804 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5805 a given theory (thms_of), or find out what theory a theorem was proved in
  5806 (theory_of_thm);
  5807 
  5808 * Bugs fixed in the inductive definition and datatype packages;
  5809 
  5810 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5811 and HOL_dup_cs obsolete;
  5812 
  5813 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5814 have been removed;
  5815 
  5816 * Simpler definition of function space in ZF;
  5817 
  5818 * new results about cardinal and ordinal arithmetic in ZF;
  5819 
  5820 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5821 types;
  5822 
  5823 :mode=text:wrap=hard:maxLineLen=72:
  5824 
  5825 
  5826 $Id$