NEWS
author berghofe
Tue Oct 21 21:22:02 2008 +0200 (2008-10-21)
changeset 28655 2822c56dd1cf
parent 28633 7b2cb494e11c
child 28676 78688a5fafc2
permissions -rw-r--r--
Example for using the generalized version of nominal_inductive.
     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 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
    51 hypotheses.  Sorts required in the course of reasoning need to be
    52 covered by the constraints in the initial statement, completed by the
    53 type instance information of the background theory.  Non-trivial sort
    54 hypotheses, which rarely occur in practice, may be specified via
    55 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
    56 
    57   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
    58 
    59 The result contains an implicit sort hypotheses as before --
    60 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
    61 normalization.
    62 
    63 * Changed defaults for unify configuration options:
    64 
    65   unify_trace_bound = 50 (formerly 25)
    66   unify_search_bound = 60 (formerly 30)
    67 
    68 * Different bookkeeping for code equations:
    69   a) On theory merge, the last set of code equations for a particular constant
    70      is taken (in accordance with the policy applied by other parts of the
    71      code generator framework).
    72   b) Code equations stemming from explicit declarations (e.g. code attribute)
    73      gain priority over default code equations stemming from definition, primrec,
    74      fun etc.
    75   INCOMPATIBILITY.
    76 
    77 * Global versions of theorems stemming from classes do not carry
    78 a parameter prefix any longer.  INCOMPATIBILITY.
    79 
    80 * Dropped "locale (open)".  INCOMPATBILITY.
    81 
    82 * Interpretation commands no longer attempt to simplify goal.
    83 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
    84 methods intro_locales and unfold_locales to clarify.
    85 
    86 * Interpretation commands no longer accept interpretation attributes.
    87 INCOMPATBILITY.
    88 
    89 * Command 'instance': attached definitions no longer accepted.
    90 INCOMPATIBILITY, use proper 'instantiation' target.
    91 
    92 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
    93 
    94 * The 'axiomatization' command now only works within a global theory
    95 context.  INCOMPATIBILITY.
    96 
    97 
    98 *** Document preparation ***
    99 
   100 * Antiquotation @{lemma} now imitates a regular terminal proof,
   101 demanding keyword 'by' and supporting the full method expression
   102 syntax just like the Isar command 'by'.
   103 
   104 
   105 *** HOL ***
   106 
   107 * Unified theorem tables for both code code generators.  Thus
   108 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   109 
   110 * Constant "undefined" replaces "arbitrary" in most occurences.
   111 
   112 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   113 Posix processes.  Avoids potentially expensive forking of the ML
   114 process.  New thread-based implementation also works on non-Unix
   115 platforms (Cygwin).  Provers are no longer hardwired, but defined
   116 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   117 commands are covered in the isar-ref manual
   118 
   119 * Wrapper scripts for remote SystemOnTPTP service allows to use
   120 sledgehammer without local ATP installation (Vampire etc.).  See also
   121 ISABELLE_HOME/contrib/SystemOnTPTP and the VAMPIRE_HOME setting
   122 variable.  Other provers may be included via suitable ML wrappers, see
   123 also src/HOL/ATP_Linkup.thy.
   124 
   125 * Normalization by evaluation now allows non-leftlinear equations.
   126 Declare with attribute [code nbe].
   127 
   128 * Command "value" now integrates different evaluation
   129 mechanisms.  The result of the first successful evaluation mechanism
   130 is printed.  In square brackets a particular named evaluation
   131 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   132 further src/HOL/ex/Eval_Examples.thy.
   133 
   134 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   135 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   136 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   137 
   138 * HOL/Orderings: added class "preorder" as superclass of "order".
   139 INCOMPATIBILITY: Instantiation proofs for order, linorder
   140 etc. slightly changed.  Some theorems named order_class.* now named
   141 preorder_class.*.
   142 
   143 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   144 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   145 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   146 of lemmas from Divides has been generalized from nat to class
   147 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   148 renames resulting from duplicate elimination:
   149 
   150     dvd_def_mod ~>          dvd_eq_mod_eq_0
   151     zero_dvd_iff ~>         dvd_0_left_iff
   152     dvd_0 ~>                dvd_0_right
   153     DIVISION_BY_ZERO_DIV ~> div_by_0
   154     DIVISION_BY_ZERO_MOD ~> mod_by_0
   155     mult_div ~>             div_mult_self2_is_id
   156     mult_mod ~>             mod_mult_self2_is_0
   157 
   158 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   159 zlcm (for int); carried together from various gcd/lcm developements in
   160 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   161 corresponding theorems renamed accordingly.  INCOMPATIBILY.  To
   162 recover tupled syntax, use syntax declarations like:
   163 
   164     hide (open) const gcd
   165     abbreviation gcd where
   166       "gcd == (%(a, b). GCD.gcd a b)"
   167     notation (output)
   168       GCD.gcd ("gcd '(_, _')")
   169 
   170 (analogously for lcm, zgcd, zlcm).
   171 
   172 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   173 
   174 * New ML antiquotation @{code}: takes constant as argument, generates
   175 corresponding code in background and inserts name of the corresponding
   176 resulting ML value/function/datatype constructor binding in place.
   177 All occurrences of @{code} with a single ML block are generated
   178 simultaneously.  Provides a generic and safe interface for
   179 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   180 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   181 application.  In future you ought refrain from ad-hoc compiling
   182 generated SML code on the ML toplevel.  Note that (for technical
   183 reasons) @{code} cannot refer to constants for which user-defined
   184 serializations are set.  Refer to the corresponding ML counterpart
   185 directly in that cases.
   186 
   187 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   188 Complex_Main.thy remain as they are.
   189 
   190 * New image HOL-Plain provides a minimal HOL with the most important
   191 tools available (inductive, datatype, primrec, ...).  By convention
   192 the corresponding theory Plain should be ancestor of every further
   193 (library) theory.  Some library theories now have ancestor Plain
   194 (instead of Main), thus theory Main occasionally has to be imported
   195 explicitly.
   196 
   197 * The metis method now fails in the usual manner, rather than raising
   198 an exception, if it determines that it cannot prove the theorem.
   199 
   200 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   201 as the structured Isar versions "cases" and "induct", cf. the
   202 corresponding "cases" and "induct" attributes.  Mutual induction rules
   203 are now presented as a list of individual projections
   204 (e.g. foo_bar.inducts for types foo and bar); the old format with
   205 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   206 rare situations a different rule is selected --- notably nested tuple
   207 elimination instead of former prod.exhaust: use explicit (case_tac t
   208 rule: prod.exhaust) here.
   209 
   210 * Attributes "cases", "induct", "coinduct" support "del" option.
   211 
   212 * Removed fact "case_split_thm", which duplicates "case_split".
   213 
   214 * Command 'rep_datatype': instead of theorem names the command now
   215 takes a list of terms denoting the constructors of the type to be
   216 represented as datatype.  The characteristic theorems have to be
   217 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   218 have disappeared in favour of existing ones:
   219 
   220     unit_induct                 ~> unit.induct
   221     prod_induct                 ~> prod.induct
   222     sum_induct                  ~> sum.induct
   223     Suc_Suc_eq                  ~> nat.inject
   224     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   225 
   226 * Library/Nat_Infinity: added addition, numeral syntax and more
   227 instantiations for algebraic structures.  Removed some duplicate
   228 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   229 
   230 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   231 menu.
   232 
   233 
   234 *** HOL-Algebra ***
   235 
   236 * New locales for orders and lattices where the equivalence relation
   237   is not restricted to equality.  INCOMPATIBILITY: all order and
   238   lattice locales use a record structure with field eq for the
   239   equivalence.
   240 
   241 * New theory of factorial domains.
   242 
   243 * Units_l_inv and Units_r_inv are now simprules by default.
   244 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   245 and/or r_inv will now also require deletion of these lemmas.
   246 
   247 * Renamed the following theorems.  INCOMPATIBILITY.
   248 UpperD ~> Upper_memD
   249 LowerD ~> Lower_memD
   250 least_carrier ~> least_closed
   251 greatest_carrier ~> greatest_closed
   252 greatest_Lower_above ~> greatest_Lower_below
   253 one_zero ~> carrier_one_zero
   254 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   255 
   256 
   257 *** HOL-NSA ***
   258 
   259 * Created new image HOL-NSA, containing theories of nonstandard
   260 analysis which were previously part of HOL-Complex.  Entry point
   261 Hyperreal.thy remains valid, but theories formerly using
   262 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   263 
   264 
   265 *** ZF ***
   266 
   267 * Proof of Zorn's Lemma for partial orders.
   268 
   269 
   270 *** ML ***
   271 
   272 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   273 to 'a -> thm, while results are always tagged with an authentic oracle
   274 name.  The Isar command 'oracle' is now polymorphic, no argument type
   275 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   276 accordingly.  Note that extra performance may be gained by producing
   277 the cterm carefully, avoiding slow Thm.cterm_of.
   278 
   279 * ML bindings produced via Isar commands are stored within the Isar
   280 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   281 become thread-safe and work with undo as expected (concerning
   282 top-level bindings, not side-effects on global references).
   283 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   284 compiler at runtime; really global bindings need to be given outside a
   285 theory. [Poly/ML 5.2 or later]
   286 
   287 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   288 context. Top-level ML bindings are stored within the proof context in
   289 a purely sequential fashion, disregarding the nested proof structure.
   290 ML bindings introduced by 'ML_prf' are discarded at the end of the
   291 proof.  [Poly/ML 5.2 or later]
   292 
   293 * Generic Toplevel.add_hook interface allows to analyze the result of
   294 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   295 for theorem dependency output of transactions resulting in a new
   296 theory state.
   297 
   298 * Name bindings in higher specification mechanisms (notably
   299 LocalTheory.define, LocalTheory.note, and derived packages) are now
   300 formalized as type Name.binding, replacing old bstring.
   301 INCOMPATIBILITY, need to wrap strings via Name.binding function, see
   302 also Name.name_of.  Packages should pass name bindings given by the
   303 user to underlying specification mechanisms; this enables precise
   304 tracking of source positions, for example.
   305 
   306 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   307 LocalTheory.note etc.) now refer to the *full* internal name, not the
   308 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   309 
   310 * Rules and tactics that read instantiations (read_instantiate,
   311 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   312 context, which is required for parsing and type-checking.  Moreover,
   313 the variables are specified as plain indexnames, not string encodings
   314 thereof.  INCOMPATIBILITY.
   315 
   316 * Disposed old type and term read functions (Sign.read_def_typ,
   317 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   318 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   319 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   320 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   321 resort for legacy applications.
   322 
   323 * Antiquotations: block-structured compilation context indicated by
   324 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   325 
   326   @{let ?pat = term}                      - term abbreviation (HO matching)
   327   @{note name = fact}                     - fact abbreviation
   328   @{thm fact}                             - singleton fact (with attributes)
   329   @{thms fact}                            - general fact (with attributes)
   330   @{lemma prop by method}                 - singleton goal
   331   @{lemma prop by meth1 meth2}            - singleton goal
   332   @{lemma prop1 ... propN by method}      - general goal
   333   @{lemma prop1 ... propN by meth1 meth2} - general goal
   334   @{lemma (open) ...}                     - open derivation
   335 
   336 
   337 *** System ***
   338 
   339 * Multithreading for Poly/ML 5.1 is no longer supported, only for
   340 Poly/ML 5.2 or later.
   341 
   342 * The Isabelle "emacs" tool provides a specific interface to invoke
   343 Proof General / Emacs, with more explicit failure if that is not
   344 installed (the old isabelle-interface script silently falls back on
   345 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   346 installation location of the Proof General distribution.
   347 
   348 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   349 the Isabelle process into a JVM/Scala application.  See
   350 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   351 process wrapper has been discontinued.)
   352 
   353 * Status messages (with exact source position information) are
   354 emitted, if proper markup print mode is enabled.  This allows
   355 user-interface components to provide detailed feedback on internal
   356 prover operations.
   357 
   358 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   359 
   360 
   361 
   362 New in Isabelle2008 (June 2008)
   363 -------------------------------
   364 
   365 *** General ***
   366 
   367 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   368 and updated, with formally checked references as hyperlinks.
   369 
   370 * Theory loader: use_thy (and similar operations) no longer set the
   371 implicit ML context, which was occasionally hard to predict and in
   372 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   373 provides a proper context already.
   374 
   375 * Theory loader: old-style ML proof scripts being *attached* to a thy
   376 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   377 'use' within a theory file will do the job.
   378 
   379 * Name space merge now observes canonical order, i.e. the second space
   380 is inserted into the first one, while existing entries in the first
   381 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   382 swap theory imports.
   383 
   384 * Syntax: symbol \<chi> is now considered a letter.  Potential
   385 INCOMPATIBILITY in identifier syntax etc.
   386 
   387 * Outer syntax: string tokens no longer admit escaped white space,
   388 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   389 white space without escapes.
   390 
   391 * Outer syntax: string tokens may contain arbitrary character codes
   392 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   393 "foo_bar".
   394 
   395 
   396 *** Pure ***
   397 
   398 * Context-dependent token translations.  Default setup reverts locally
   399 fixed variables, and adds hilite markup for undeclared frees.
   400 
   401 * Unused theorems can be found using the new command 'unused_thms'.
   402 There are three ways of invoking it:
   403 
   404 (1) unused_thms
   405      Only finds unused theorems in the current theory.
   406 
   407 (2) unused_thms thy_1 ... thy_n -
   408      Finds unused theorems in the current theory and all of its ancestors,
   409      excluding the theories thy_1 ... thy_n and all of their ancestors.
   410 
   411 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   412      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   413      their ancestors, excluding the theories thy_1 ... thy_n and all of
   414      their ancestors.
   415 
   416 In order to increase the readability of the list produced by
   417 unused_thms, theorems that have been created by a particular instance
   418 of a theory command such as 'inductive' or 'function' are considered
   419 to belong to the same "group", meaning that if at least one theorem in
   420 this group is used, the other theorems in the same group are no longer
   421 reported as unused.  Moreover, if all theorems in the group are
   422 unused, only one theorem in the group is displayed.
   423 
   424 Note that proof objects have to be switched on in order for
   425 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   426 usually the case when using Proof General with the default settings).
   427 
   428 * Authentic naming of facts disallows ad-hoc overwriting of previous
   429 theorems within the same name space.  INCOMPATIBILITY, need to remove
   430 duplicate fact bindings, or even accidental fact duplications.  Note
   431 that tools may maintain dynamically scoped facts systematically, using
   432 PureThy.add_thms_dynamic.
   433 
   434 * Command 'hide' now allows to hide from "fact" name space as well.
   435 
   436 * Eliminated destructive theorem database, simpset, claset, and
   437 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   438 update of theories within ML code.
   439 
   440 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   441 INCOMPATIBILITY, object-logics depending on former Pure require
   442 additional setup PureThy.old_appl_syntax_setup; object-logics
   443 depending on former CPure need to refer to Pure.
   444 
   445 * Commands 'use' and 'ML' are now purely functional, operating on
   446 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   447 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   448 INCOMPATIBILITY.
   449 
   450 * Command 'setup': discontinued implicit version with ML reference.
   451 
   452 * Instantiation target allows for simultaneous specification of class
   453 instance operations together with an instantiation proof.
   454 Type-checking phase allows to refer to class operations uniformly.
   455 See src/HOL/Complex/Complex.thy for an Isar example and
   456 src/HOL/Library/Eval.thy for an ML example.
   457 
   458 * Indexing of literal facts: be more serious about including only
   459 facts from the visible specification/proof context, but not the
   460 background context (locale etc.).  Affects `prop` notation and method
   461 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   462 situations.
   463 
   464 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   465 "(open)" option, which used to expose internal bound variables to the
   466 proof text.
   467 
   468 * Isar statements: removed obsolete case "rule_context".
   469 INCOMPATIBILITY, better use explicit fixes/assumes.
   470 
   471 * Locale proofs: default proof step now includes 'unfold_locales';
   472 hence 'proof' without argument may be used to unfold locale
   473 predicates.
   474 
   475 
   476 *** Document preparation ***
   477 
   478 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   479 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   480 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   481 spot); renamed link color from "darkblue" to "linkcolor" (default
   482 value unchanged, can be redefined via \definecolor); no longer sets
   483 "a4paper" option (unnecessary or even intrusive).
   484 
   485 * Antiquotation @{lemma A method} proves proposition A by the given
   486 method (either a method name or a method name plus (optional) method
   487 arguments in parentheses) and prints A just like @{prop A}.
   488 
   489 
   490 *** HOL ***
   491 
   492 * New primrec package.  Specification syntax conforms in style to
   493 definition/function/....  No separate induction rule is provided.  The
   494 "primrec" command distinguishes old-style and new-style specifications
   495 by syntax.  The former primrec package is now named OldPrimrecPackage.
   496 When adjusting theories, beware: constants stemming from new-style
   497 primrec specifications have authentic syntax.
   498 
   499 * Metis prover is now an order of magnitude faster, and also works
   500 with multithreading.
   501 
   502 * Metis: the maximum number of clauses that can be produced from a
   503 theorem is now given by the attribute max_clauses.  Theorems that
   504 exceed this number are ignored, with a warning printed.
   505 
   506 * Sledgehammer no longer produces structured proofs by default. To
   507 enable, declare [[sledgehammer_full = true]].  Attributes
   508 reconstruction_modulus, reconstruction_sorts renamed
   509 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   510 
   511 * Method "induct_scheme" derives user-specified induction rules
   512 from well-founded induction and completeness of patterns. This factors
   513 out some operations that are done internally by the function package
   514 and makes them available separately.  See
   515 src/HOL/ex/Induction_Scheme.thy for examples.
   516 
   517 * More flexible generation of measure functions for termination
   518 proofs: Measure functions can be declared by proving a rule of the
   519 form "is_measure f" and giving it the [measure_function] attribute.
   520 The "is_measure" predicate is logically meaningless (always true), and
   521 just guides the heuristic.  To find suitable measure functions, the
   522 termination prover sets up the goal "is_measure ?f" of the appropriate
   523 type and generates all solutions by prolog-style backwards proof using
   524 the declared rules.
   525 
   526 This setup also deals with rules like 
   527 
   528   "is_measure f ==> is_measure (list_size f)"
   529 
   530 which accommodates nested datatypes that recurse through lists.
   531 Similar rules are predeclared for products and option types.
   532 
   533 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   534 
   535   INCOMPATIBILITIES:
   536 
   537   - Definitions of overloaded constants on sets have to be replaced by
   538     definitions on => and bool.
   539 
   540   - Some definitions of overloaded operators on sets can now be proved
   541     using the definitions of the operators on => and bool.  Therefore,
   542     the following theorems have been renamed:
   543 
   544       subset_def   -> subset_eq
   545       psubset_def  -> psubset_eq
   546       set_diff_def -> set_diff_eq
   547       Compl_def    -> Compl_eq
   548       Sup_set_def  -> Sup_set_eq
   549       Inf_set_def  -> Inf_set_eq
   550       sup_set_def  -> sup_set_eq
   551       inf_set_def  -> inf_set_eq
   552 
   553   - Due to the incompleteness of the HO unification algorithm, some
   554     rules such as subst may require manual instantiation, if some of
   555     the unknowns in the rule is a set.
   556 
   557   - Higher order unification and forward proofs:
   558     The proof pattern
   559 
   560       have "P (S::'a set)" <...>
   561       then have "EX S. P S" ..
   562 
   563     no longer works (due to the incompleteness of the HO unification
   564     algorithm) and must be replaced by the pattern
   565 
   566       have "EX S. P S"
   567       proof
   568         show "P S" <...>
   569       qed
   570 
   571   - Calculational reasoning with subst (or similar rules):
   572     The proof pattern
   573 
   574       have "P (S::'a set)" <...>
   575       also have "S = T" <...>
   576       finally have "P T" .
   577 
   578     no longer works (for similar reasons as the previous example) and
   579     must be replaced by something like
   580 
   581       have "P (S::'a set)" <...>
   582       moreover have "S = T" <...>
   583       ultimately have "P T" by simp
   584 
   585   - Tactics or packages written in ML code:
   586     Code performing pattern matching on types via
   587 
   588       Type ("set", [T]) => ...
   589 
   590     must be rewritten. Moreover, functions like strip_type or
   591     binder_types no longer return the right value when applied to a
   592     type of the form
   593 
   594       T1 => ... => Tn => U => bool
   595 
   596     rather than
   597 
   598       T1 => ... => Tn => U set
   599 
   600 * Merged theories Wellfounded_Recursion, Accessible_Part and
   601 Wellfounded_Relations to theory Wellfounded.
   602 
   603 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   604 
   605 * Class finite no longer treats UNIV as class parameter.  Use class
   606 enum from theory Library/Enum instead to achieve a similar effect.
   607 INCOMPATIBILITY.
   608 
   609 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   610 and "Cons".  INCOMPATIBILITY.
   611 
   612 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   613 Potential INCOMPATIBILITY.
   614 
   615 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   616 injective_fst_snd removed, use split_eta and prod_eqI instead.
   617 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   618 
   619 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   620 the same name in theory Orderings:
   621 
   622   less_trans
   623   less_linear
   624   le_imp_less_or_eq
   625   le_less_trans
   626   less_le_trans
   627   less_not_sym
   628   less_asym
   629 
   630 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   631 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   632 and different variable names.
   633 
   634 * Library/Option_ord.thy: Canonical order on option type.
   635 
   636 * Library/RBT.thy: Red-black trees, an efficient implementation of
   637 finite maps.
   638 
   639 * Library/Countable.thy: Type class for countable types.
   640 
   641 * Theory Int: The representation of numerals has changed.  The infix
   642 operator BIT and the bit datatype with constructors B0 and B1 have
   643 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   644 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   645 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   646 accordingly.
   647 
   648 * Theory Nat: definition of <= and < on natural numbers no longer
   649 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   650 le_def and less_def have disappeared.  Consider lemmas not_less
   651 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   652 
   653 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   654 (whose purpose mainly is for various fold_set functionals) have been
   655 abandoned in favor of the existing algebraic classes
   656 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   657 lower_semilattice (resp. upper_semilattice) and linorder.
   658 INCOMPATIBILITY.
   659 
   660 * Theory Transitive_Closure: induct and cases rules now declare proper
   661 case_names ("base" and "step").  INCOMPATIBILITY.
   662 
   663 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   664 lattices.  The form set-specific version is available as
   665 Inductive.lfp_ordinal_induct_set.
   666 
   667 * Renamed theorems "power.simps" to "power_int.simps".
   668 INCOMPATIBILITY.
   669 
   670 * Class semiring_div provides basic abstract properties of semirings
   671 with division and modulo operations.  Subsumes former class dvd_mod.
   672 
   673 * Merged theories IntDef, Numeral and IntArith into unified theory
   674 Int.  INCOMPATIBILITY.
   675 
   676 * Theory Library/Code_Index: type "index" now represents natural
   677 numbers rather than integers.  INCOMPATIBILITY.
   678 
   679 * New class "uminus" with operation "uminus" (split of from class
   680 "minus" which now only has operation "minus", binary).
   681 INCOMPATIBILITY.
   682 
   683 * Constants "card", "internal_split", "option_map" now with authentic
   684 syntax.  INCOMPATIBILITY.
   685 
   686 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   687 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   688 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   689 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   690 Sup_set_def, le_def, less_def, option_map_def now with object
   691 equality.  INCOMPATIBILITY.
   692 
   693 * Records. Removed K_record, and replaced it by pure lambda term
   694 %x. c. The simplifier setup is now more robust against eta expansion.
   695 INCOMPATIBILITY: in cases explicitly referring to K_record.
   696 
   697 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   698 
   699 * Library/ListVector: new theory of arithmetic vector operations.
   700 
   701 * Library/Order_Relation: new theory of various orderings as sets of
   702 pairs.  Defines preorders, partial orders, linear orders and
   703 well-orders on sets and on types.
   704 
   705 
   706 *** ZF ***
   707 
   708 * Renamed some theories to allow to loading both ZF and HOL in the
   709 same session:
   710 
   711   Datatype  -> Datatype_ZF
   712   Inductive -> Inductive_ZF
   713   Int       -> Int_ZF
   714   IntDiv    -> IntDiv_ZF
   715   Nat       -> Nat_ZF
   716   List      -> List_ZF
   717   Main      -> Main_ZF
   718 
   719 INCOMPATIBILITY: ZF theories that import individual theories below
   720 Main might need to be adapted.  Regular theory Main is still
   721 available, as trivial extension of Main_ZF.
   722 
   723 
   724 *** ML ***
   725 
   726 * ML within Isar: antiquotation @{const name} or @{const
   727 name(typargs)} produces statically-checked Const term.
   728 
   729 * Functor NamedThmsFun: data is available to the user as dynamic fact
   730 (of the same name).  Removed obsolete print command.
   731 
   732 * Removed obsolete "use_legacy_bindings" function.
   733 
   734 * The ``print mode'' is now a thread-local value derived from a global
   735 template (the former print_mode reference), thus access becomes
   736 non-critical.  The global print_mode reference is for session
   737 management only; user-code should use print_mode_value,
   738 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   739 
   740 * Functions system/system_out provide a robust way to invoke external
   741 shell commands, with propagation of interrupts (requires Poly/ML 5.2).
   742 Do not use OS.Process.system etc. from the basis library!
   743 
   744 
   745 *** System ***
   746 
   747 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   748 in accordance with Proof General 3.7, which prefers GNU emacs.
   749 
   750 * isatool tty runs Isabelle process with plain tty interaction;
   751 optional line editor may be specified via ISABELLE_LINE_EDITOR
   752 setting, the default settings attempt to locate "ledit" and "rlwrap".
   753 
   754 * isatool browser now works with Cygwin as well, using general
   755 "javapath" function defined in Isabelle process environment.
   756 
   757 * YXML notation provides a simple and efficient alternative to
   758 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
   759 isatool yxml as described in the Isabelle system manual.
   760 
   761 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   762 provides general wrapper for managing an Isabelle process in a robust
   763 fashion, with ``cooked'' output from stdin/stderr.
   764 
   765 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   766 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   767 
   768 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
   769 way of changing the user's settings is via
   770 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   771 script.
   772 
   773 * Multithreading.max_threads := 0 refers to the number of actual CPU
   774 cores of the underlying machine, which is a good starting point for
   775 optimal performance tuning.  The corresponding usedir option -M allows
   776 "max" as an alias for "0".  WARNING: does not work on certain versions
   777 of Mac OS (with Poly/ML 5.1).
   778 
   779 * isabelle-process: non-ML sessions are run with "nice", to reduce the
   780 adverse effect of Isabelle flooding interactive front-ends (notably
   781 ProofGeneral / XEmacs).
   782 
   783 
   784 
   785 New in Isabelle2007 (November 2007)
   786 -----------------------------------
   787 
   788 *** General ***
   789 
   790 * More uniform information about legacy features, notably a
   791 warning/error of "Legacy feature: ...", depending on the state of the
   792 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   793 legacy features will disappear eventually.
   794 
   795 * Theory syntax: the header format ``theory A = B + C:'' has been
   796 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   797 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   798 
   799 * Theory syntax: the old non-Isar theory file format has been
   800 discontinued altogether.  Note that ML proof scripts may still be used
   801 with Isar theories; migration is usually quite simple with the ML
   802 function use_legacy_bindings.  INCOMPATIBILITY.
   803 
   804 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   805 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   806 quotes.
   807 
   808 * Theory loader: be more serious about observing the static theory
   809 header specifications (including optional directories), but not the
   810 accidental file locations of previously successful loads.  The strict
   811 update policy of former update_thy is now already performed by
   812 use_thy, so the former has been removed; use_thys updates several
   813 theories simultaneously, just as 'imports' within a theory header
   814 specification, but without merging the results.  Potential
   815 INCOMPATIBILITY: may need to refine theory headers and commands
   816 ROOT.ML which depend on load order.
   817 
   818 * Theory loader: optional support for content-based file
   819 identification, instead of the traditional scheme of full physical
   820 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   821 (cf. the system manual).  The new scheme allows to work with
   822 non-finished theories in persistent session images, such that source
   823 files may be moved later on without requiring reloads.
   824 
   825 * Theory loader: old-style ML proof scripts being *attached* to a thy
   826 file (with the same base name as the theory) are considered a legacy
   827 feature, which will disappear eventually. Even now, the theory loader
   828 no longer maintains dependencies on such files.
   829 
   830 * Syntax: the scope for resolving ambiguities via type-inference is
   831 now limited to individual terms, instead of whole simultaneous
   832 specifications as before. This greatly reduces the complexity of the
   833 syntax module and improves flexibility by separating parsing and
   834 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   835 'fixes' etc.) are required in rare situations.
   836 
   837 * Syntax: constants introduced by new-style packages ('definition',
   838 'abbreviation' etc.) are passed through the syntax module in
   839 ``authentic mode''. This means that associated mixfix annotations
   840 really stick to such constants, independently of potential name space
   841 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   842 trees are represented slightly differently, may need to adapt syntax
   843 translations accordingly. Use CONST marker in 'translations' and
   844 @{const_syntax} antiquotation in 'parse_translation' etc.
   845 
   846 * Legacy goal package: reduced interface to the bare minimum required
   847 to keep existing proof scripts running.  Most other user-level
   848 functions are now part of the OldGoals structure, which is *not* open
   849 by default (consider isatool expandshort before open OldGoals).
   850 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   851 these tend to cause confusion about the actual goal (!) context being
   852 used here, which is not necessarily the same as the_context().
   853 
   854 * Command 'find_theorems': supports "*" wild-card in "name:"
   855 criterion; "with_dups" option.  Certain ProofGeneral versions might
   856 support a specific search form (see ProofGeneral/CHANGES).
   857 
   858 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   859 by default, which means that "prems" (and also "fixed variables") are
   860 suppressed from proof state output.  Note that the ProofGeneral
   861 settings mechanism allows to change and save options persistently, but
   862 older versions of Isabelle will fail to start up if a negative prems
   863 limit is imposed.
   864 
   865 * Local theory targets may be specified by non-nested blocks of
   866 ``context/locale/class ... begin'' followed by ``end''.  The body may
   867 contain definitions, theorems etc., including any derived mechanism
   868 that has been implemented on top of these primitives.  This concept
   869 generalizes the existing ``theorem (in ...)'' towards more versatility
   870 and scalability.
   871 
   872 * Proof General interface: proper undo of final 'end' command;
   873 discontinued Isabelle/classic mode (ML proof scripts).
   874 
   875 
   876 *** Document preparation ***
   877 
   878 * Added antiquotation @{theory name} which prints the given name,
   879 after checking that it refers to a valid ancestor theory in the
   880 current context.
   881 
   882 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   883 check the given source text as ML type/structure, printing verbatim.
   884 
   885 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   886 "c args == rhs" given in the current context.  (Any number of
   887 arguments may be given on the LHS.)
   888 
   889 
   890 *** Pure ***
   891 
   892 * The 'class' package offers a combination of axclass and locale to
   893 achieve Haskell-like type classes in Isabelle.  Definitions and
   894 theorems within a class context produce both relative results (with
   895 implicit parameters according to the locale context), and polymorphic
   896 constants with qualified polymorphism (according to the class
   897 context).  Within the body context of a 'class' target, a separate
   898 syntax layer ("user space type system") takes care of converting
   899 between global polymorphic consts and internal locale representation.
   900 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   901 "isatool doc classes" provides a tutorial.
   902 
   903 * Generic code generator framework allows to generate executable
   904 code for ML and Haskell (including Isabelle classes).  A short usage
   905 sketch:
   906 
   907     internal compilation:
   908         export_code <list of constants (term syntax)> in SML
   909     writing SML code to a file:
   910         export_code <list of constants (term syntax)> in SML <filename>
   911     writing OCaml code to a file:
   912         export_code <list of constants (term syntax)> in OCaml <filename>
   913     writing Haskell code to a bunch of files:
   914         export_code <list of constants (term syntax)> in Haskell <filename>
   915 
   916     evaluating closed propositions to True/False using code generation:
   917         method ``eval''
   918 
   919 Reasonable default setup of framework in HOL.
   920 
   921 Theorem attributs for selecting and transforming function equations theorems:
   922 
   923     [code fun]:        select a theorem as function equation for a specific constant
   924     [code fun del]:    deselect a theorem as function equation for a specific constant
   925     [code inline]:     select an equation theorem for unfolding (inlining) in place
   926     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   927 
   928 User-defined serializations (target in {SML, OCaml, Haskell}):
   929 
   930     code_const <and-list of constants (term syntax)>
   931       {(target) <and-list of const target syntax>}+
   932 
   933     code_type <and-list of type constructors>
   934       {(target) <and-list of type target syntax>}+
   935 
   936     code_instance <and-list of instances>
   937       {(target)}+
   938         where instance ::= <type constructor> :: <class>
   939 
   940     code_class <and_list of classes>
   941       {(target) <and-list of class target syntax>}+
   942         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   943 
   944 code_instance and code_class only are effective to target Haskell.
   945 
   946 For example usage see src/HOL/ex/Codegenerator.thy and
   947 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   948 generation from Isabelle/HOL theories is available via "isatool doc
   949 codegen".
   950 
   951 * Code generator: consts in 'consts_code' Isar commands are now
   952 referred to by usual term syntax (including optional type
   953 annotations).
   954 
   955 * Command 'no_translations' removes translation rules from theory
   956 syntax.
   957 
   958 * Overloaded definitions are now actually checked for acyclic
   959 dependencies.  The overloading scheme is slightly more general than
   960 that of Haskell98, although Isabelle does not demand an exact
   961 correspondence to type class and instance declarations.
   962 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   963 exotic versions of overloading -- at the discretion of the user!
   964 
   965 Polymorphic constants are represented via type arguments, i.e. the
   966 instantiation that matches an instance against the most general
   967 declaration given in the signature.  For example, with the declaration
   968 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   969 as c(nat).  Overloading is essentially simultaneous structural
   970 recursion over such type arguments.  Incomplete specification patterns
   971 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   972 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   973 Command 'print_theory' outputs the normalized system of recursive
   974 equations, see section "definitions".
   975 
   976 * Configuration options are maintained within the theory or proof
   977 context (with name and type bool/int/string), providing a very simple
   978 interface to a poor-man's version of general context data.  Tools may
   979 declare options in ML (e.g. using Attrib.config_int) and then refer to
   980 these values using Config.get etc.  Users may change options via an
   981 associated attribute of the same name.  This form of context
   982 declaration works particularly well with commands 'declare' or
   983 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   984 very easy to avoid global references, which would not observe Isar
   985 toplevel undo/redo and fail to work with multithreading.
   986 
   987 Various global ML references of Pure and HOL have been turned into
   988 configuration options:
   989 
   990   Unify.search_bound		unify_search_bound
   991   Unify.trace_bound		unify_trace_bound
   992   Unify.trace_simp		unify_trace_simp
   993   Unify.trace_types		unify_trace_types
   994   Simplifier.simp_depth_limit	simp_depth_limit
   995   Blast.depth_limit		blast_depth_limit
   996   DatatypeProp.dtK		datatype_distinctness_limit
   997   fast_arith_neq_limit  	fast_arith_neq_limit
   998   fast_arith_split_limit	fast_arith_split_limit
   999 
  1000 * Named collections of theorems may be easily installed as context
  1001 data using the functor NamedThmsFun (see also
  1002 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1003 attributes; there is also a toplevel print command.  This facility is
  1004 just a common case of general context data, which is the preferred way
  1005 for anything more complex than just a list of facts in canonical
  1006 order.
  1007 
  1008 * Isar: command 'declaration' augments a local theory by generic
  1009 declaration functions written in ML.  This enables arbitrary content
  1010 being added to the context, depending on a morphism that tells the
  1011 difference of the original declaration context wrt. the application
  1012 context encountered later on.
  1013 
  1014 * Isar: proper interfaces for simplification procedures.  Command
  1015 'simproc_setup' declares named simprocs (with match patterns, and body
  1016 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1017 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1018 
  1019 * Isar: an extra pair of brackets around attribute declarations
  1020 abbreviates a theorem reference involving an internal dummy fact,
  1021 which will be ignored later --- only the effect of the attribute on
  1022 the background context will persist.  This form of in-place
  1023 declarations is particularly useful with commands like 'declare' and
  1024 'using', for example ``have A using [[simproc a]] by simp''.
  1025 
  1026 * Isar: method "assumption" (and implicit closing of subproofs) now
  1027 takes simple non-atomic goal assumptions into account: after applying
  1028 an assumption as a rule the resulting subgoals are solved by atomic
  1029 assumption steps.  This is particularly useful to finish 'obtain'
  1030 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1031 without referring to the original premise "!!x. P x ==> thesis" in the
  1032 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1033 more permissive.
  1034 
  1035 * Isar: implicit use of prems from the Isar proof context is
  1036 considered a legacy feature.  Common applications like ``have A .''
  1037 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1038 referencing facts explicitly here improves readability and
  1039 maintainability of proof texts.
  1040 
  1041 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1042 the obtained context from the course of reasoning!  For example:
  1043 
  1044   assume "EX x y. A x & B y"   -- "any previous fact"
  1045   then guess x and y by clarify
  1046 
  1047 This technique is potentially adventurous, depending on the facts and
  1048 proof tools being involved here.
  1049 
  1050 * Isar: known facts from the proof context may be specified as literal
  1051 propositions, using ASCII back-quote syntax.  This works wherever
  1052 named facts used to be allowed so far, in proof commands, proof
  1053 methods, attributes etc.  Literal facts are retrieved from the context
  1054 according to unification of type and term parameters.  For example,
  1055 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1056 theorems in the current context, then these are valid literal facts:
  1057 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1058 
  1059 There is also a proof method "fact" which does the same composition
  1060 for explicit goal states, e.g. the following proof texts coincide with
  1061 certain special cases of literal facts:
  1062 
  1063   have "A" by fact                 ==  note `A`
  1064   have "A ==> B" by fact           ==  note `A ==> B`
  1065   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1066   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1067 
  1068 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1069 outer syntax.  Thus symbolic identifiers may be used without
  1070 additional white space in declarations like this: ``assume *: A''.
  1071 
  1072 * Isar: 'print_facts' prints all local facts of the current context,
  1073 both named and unnamed ones.
  1074 
  1075 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1076 
  1077   def x == "t" and y == "u"
  1078 
  1079 * Isar: added command 'unfolding', which is structurally similar to
  1080 'using', but affects both the goal state and facts by unfolding given
  1081 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1082 'unfolded' attribute may be replaced by first-class proof text.
  1083 
  1084 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1085 and command 'unfolding' now all support object-level equalities
  1086 (potentially conditional).  The underlying notion of rewrite rule is
  1087 analogous to the 'rule_format' attribute, but *not* that of the
  1088 Simplifier (which is usually more generous).
  1089 
  1090 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1091 premises of a theorem by n. Useful in conjunction with drule.
  1092 
  1093 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1094 method expression within a sandbox consisting of the first N
  1095 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1096 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1097 simplifies all new goals that emerge from applying rule foo to the
  1098 originally first one.
  1099 
  1100 * Isar: schematic goals are no longer restricted to higher-order
  1101 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1102 expected.
  1103 
  1104 * Isar: the conclusion of a long theorem statement is now either
  1105 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1106 (essentially a disjunction of cases with local parameters and
  1107 assumptions).  The latter allows to express general elimination rules
  1108 adequately; in this notation common elimination rules look like this:
  1109 
  1110   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1111     assumes "EX x. P x"
  1112     obtains x where "P x"
  1113 
  1114   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1115     assumes "A & B"
  1116     obtains A and B
  1117 
  1118   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1119     assumes "A | B"
  1120     obtains
  1121       A
  1122     | B
  1123 
  1124 The subsequent classical rules even refer to the formal "thesis"
  1125 explicitly:
  1126 
  1127   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1128     obtains "~ thesis"
  1129 
  1130   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1131     obtains "thesis ==> something"
  1132 
  1133 The actual proof of an 'obtains' statement is analogous to that of the
  1134 Isar proof element 'obtain', only that there may be several cases.
  1135 Optional case names may be specified in parentheses; these will be
  1136 available both in the present proof and as annotations in the
  1137 resulting rule, for later use with the 'cases' method (cf. attribute
  1138 case_names).
  1139 
  1140 * Isar: the assumptions of a long theorem statement are available as
  1141 "assms" fact in the proof context.  This is more appropriate than the
  1142 (historical) "prems", which refers to all assumptions of the current
  1143 context, including those from the target locale, proof body etc.
  1144 
  1145 * Isar: 'print_statement' prints theorems from the current theory or
  1146 proof context in long statement form, according to the syntax of a
  1147 top-level lemma.
  1148 
  1149 * Isar: 'obtain' takes an optional case name for the local context
  1150 introduction rule (default "that").
  1151 
  1152 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1153 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1154 to occur.
  1155 
  1156 * Pure: syntax "CONST name" produces a fully internalized constant
  1157 according to the current context.  This is particularly useful for
  1158 syntax translations that should refer to internal constant
  1159 representations independently of name spaces.
  1160 
  1161 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1162 instead of "FOO ". This allows multiple binder declarations to coexist
  1163 in the same context.  INCOMPATIBILITY.
  1164 
  1165 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1166 primitive that also works in a locale context (both for constants and
  1167 fixed variables). Type declaration and internal syntactic representation
  1168 of given constants retrieved from the context. Likewise, the
  1169 'no_notation' command allows to remove given syntax annotations from the
  1170 current context.
  1171 
  1172 * Isar/locales: new derived specification elements 'axiomatization',
  1173 'definition', 'abbreviation', which support type-inference, admit
  1174 object-level specifications (equality, equivalence).  See also the
  1175 isar-ref manual.  Examples:
  1176 
  1177   axiomatization
  1178     eq  (infix "===" 50) where
  1179     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1180 
  1181   definition "f x y = x + y + 1"
  1182   definition g where "g x = f x x"
  1183 
  1184   abbreviation
  1185     neq  (infix "=!=" 50) where
  1186     "x =!= y == ~ (x === y)"
  1187 
  1188 These specifications may be also used in a locale context.  Then the
  1189 constants being introduced depend on certain fixed parameters, and the
  1190 constant name is qualified by the locale base name.  An internal
  1191 abbreviation takes care for convenient input and output, making the
  1192 parameters implicit and using the original short name.  See also
  1193 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1194 entities from a monomorphic theory.
  1195 
  1196 Presently, abbreviations are only available 'in' a target locale, but
  1197 not inherited by general import expressions.  Also note that
  1198 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1199 'translations' in common applications.  The "no_abbrevs" print mode
  1200 prevents folding of abbreviations in term output.
  1201 
  1202 Concrete syntax is attached to specified constants in internal form,
  1203 independently of name spaces.  The parse tree representation is
  1204 slightly different -- use 'notation' instead of raw 'syntax', and
  1205 'translations' with explicit "CONST" markup to accommodate this.
  1206 
  1207 * Pure/Isar: unified syntax for new-style specification mechanisms
  1208 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1209 full type inference and dummy patterns ("_").  For example:
  1210 
  1211   definition "K x _ = x"
  1212 
  1213   inductive conj for A B
  1214   where "A ==> B ==> conj A B"
  1215 
  1216 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1217 the current context.  Print mode "no_abbrevs" prevents inversion of
  1218 abbreviations on output.
  1219 
  1220 * Isar/locales: improved parameter handling: use of locales "var" and
  1221 "struct" no longer necessary; - parameter renamings are no longer
  1222 required to be injective.  For example, this allows to define
  1223 endomorphisms as locale endom = homom mult mult h.
  1224 
  1225 * Isar/locales: changed the way locales with predicates are defined.
  1226 Instead of accumulating the specification, the imported expression is
  1227 now an interpretation.  INCOMPATIBILITY: different normal form of
  1228 locale expressions.  In particular, in interpretations of locales with
  1229 predicates, goals repesenting already interpreted fragments are not
  1230 removed automatically.  Use methods `intro_locales' and
  1231 `unfold_locales'; see below.
  1232 
  1233 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1234 provide backward reasoning on locales predicates.  The methods are
  1235 aware of interpretations and discharge corresponding goals.
  1236 `intro_locales' is less aggressive then `unfold_locales' and does not
  1237 unfold predicates to assumptions.
  1238 
  1239 * Isar/locales: the order in which locale fragments are accumulated
  1240 has changed.  This enables to override declarations from fragments due
  1241 to interpretations -- for example, unwanted simp rules.
  1242 
  1243 * Isar/locales: interpretation in theories and proof contexts has been
  1244 extended.  One may now specify (and prove) equations, which are
  1245 unfolded in interpreted theorems.  This is useful for replacing
  1246 defined concepts (constants depending on locale parameters) by
  1247 concepts already existing in the target context.  Example:
  1248 
  1249   interpretation partial_order ["op <= :: [int, int] => bool"]
  1250     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1251 
  1252 Typically, the constant `partial_order.less' is created by a
  1253 definition specification element in the context of locale
  1254 partial_order.
  1255 
  1256 * Method "induct": improved internal context management to support
  1257 local fixes and defines on-the-fly. Thus explicit meta-level
  1258 connectives !!  and ==> are rarely required anymore in inductive goals
  1259 (using object-logic connectives for this purpose has been long
  1260 obsolete anyway). Common proof patterns are explained in
  1261 src/HOL/Induct/Common_Patterns.thy, see also
  1262 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1263 examples.
  1264 
  1265 * Method "induct": improved handling of simultaneous goals. Instead of
  1266 introducing object-level conjunction, the statement is now split into
  1267 several conclusions, while the corresponding symbolic cases are nested
  1268 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1269 see src/HOL/Induct/Common_Patterns.thy, for example.
  1270 
  1271 * Method "induct": mutual induction rules are now specified as a list
  1272 of rule sharing the same induction cases. HOL packages usually provide
  1273 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1274 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1275 mutual induction rules differently, i.e. like this:
  1276 
  1277   (induct rule: foo_bar.inducts)
  1278   (induct set: foo bar)
  1279   (induct pred: foo bar)
  1280   (induct type: foo bar)
  1281 
  1282 The ML function ProjectRule.projections turns old-style rules into the
  1283 new format.
  1284 
  1285 * Method "coinduct": dual of induction, see
  1286 src/HOL/Library/Coinductive_List.thy for various examples.
  1287 
  1288 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1289 considered a legacy feature.
  1290 
  1291 * Attribute "symmetric" produces result with standardized schematic
  1292 variables (index 0).  Potential INCOMPATIBILITY.
  1293 
  1294 * Simplifier: by default the simplifier trace only shows top level
  1295 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1296 default. Thus there is less danger of being flooded by the trace. The
  1297 trace indicates where parts have been suppressed.
  1298   
  1299 * Provers/classical: removed obsolete classical version of elim_format
  1300 attribute; classical elim/dest rules are now treated uniformly when
  1301 manipulating the claset.
  1302 
  1303 * Provers/classical: stricter checks to ensure that supplied intro,
  1304 dest and elim rules are well-formed; dest and elim rules must have at
  1305 least one premise.
  1306 
  1307 * Provers/classical: attributes dest/elim/intro take an optional
  1308 weight argument for the rule (just as the Pure versions).  Weights are
  1309 ignored by automated tools, but determine the search order of single
  1310 rule steps.
  1311 
  1312 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1313 where the body does not mention the bound variable.  Note that dummy
  1314 patterns implicitly depend on their context of bounds, which makes
  1315 "{_. _}" match any set comprehension as expected.  Potential
  1316 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1317 constant "_idtdummy" in the binding position.
  1318 
  1319 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1320 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1321 for example "A -> B" => "Pi A (%_. B)".
  1322 
  1323 * Pure: 'class_deps' command visualizes the subclass relation, using
  1324 the graph browser tool.
  1325 
  1326 * Pure: 'print_theory' now suppresses certain internal declarations by
  1327 default; use '!' option for full details.
  1328 
  1329 
  1330 *** HOL ***
  1331 
  1332 * Method "metis" proves goals by applying the Metis general-purpose
  1333 resolution prover (see also http://gilith.com/software/metis/).
  1334 Examples are in the directory MetisExamples.  WARNING: the
  1335 Isabelle/HOL-Metis integration does not yet work properly with
  1336 multi-threading.
  1337   
  1338 * Command 'sledgehammer' invokes external automatic theorem provers as
  1339 background processes.  It generates calls to the "metis" method if
  1340 successful. These can be pasted into the proof.  Users do not have to
  1341 wait for the automatic provers to return.  WARNING: does not really
  1342 work with multi-threading.
  1343 
  1344 * New "auto_quickcheck" feature tests outermost goal statements for
  1345 potential counter-examples.  Controlled by ML references
  1346 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1347 5000 milliseconds).  Fails silently if statements is outside of
  1348 executable fragment, or any other codgenerator problem occurs.
  1349 
  1350 * New constant "undefined" with axiom "undefined x = undefined".
  1351 
  1352 * Added class "HOL.eq", allowing for code generation with polymorphic
  1353 equality.
  1354 
  1355 * Some renaming of class constants due to canonical name prefixing in
  1356 the new 'class' package:
  1357 
  1358     HOL.abs ~> HOL.abs_class.abs
  1359     HOL.divide ~> HOL.divide_class.divide
  1360     0 ~> HOL.zero_class.zero
  1361     1 ~> HOL.one_class.one
  1362     op + ~> HOL.plus_class.plus
  1363     op - ~> HOL.minus_class.minus
  1364     uminus ~> HOL.minus_class.uminus
  1365     op * ~> HOL.times_class.times
  1366     op < ~> HOL.ord_class.less
  1367     op <= > HOL.ord_class.less_eq
  1368     Nat.power ~> Power.power_class.power
  1369     Nat.size ~> Nat.size_class.size
  1370     Numeral.number_of ~> Numeral.number_class.number_of
  1371     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1372     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1373     Orderings.min ~> Orderings.ord_class.min
  1374     Orderings.max ~> Orderings.ord_class.max
  1375     Divides.op div ~> Divides.div_class.div
  1376     Divides.op mod ~> Divides.div_class.mod
  1377     Divides.op dvd ~> Divides.div_class.dvd
  1378 
  1379 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1380 
  1381 a) User-defined constants using any of the names "plus", "minus",
  1382 "times", "less" or "less_eq". The standard syntax translations for
  1383 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1384 names.
  1385 
  1386 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1387 INCOMPATIBILITY: use more specific names.
  1388 
  1389 c) Permutative equations (e.g. "a + b = b + a")
  1390 Since the change of names also changes the order of terms, permutative
  1391 rewrite rules may get applied in a different order. Experience shows
  1392 that this is rarely the case (only two adaptions in the whole Isabelle
  1393 distribution).  INCOMPATIBILITY: rewrite proofs
  1394 
  1395 d) ML code directly refering to constant names
  1396 This in general only affects hand-written proof tactics, simprocs and
  1397 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1398 Consider using @{const_name} antiquotation.
  1399 
  1400 * New class "default" with associated constant "default".
  1401 
  1402 * Function "sgn" is now overloaded and available on int, real, complex
  1403 (and other numeric types), using class "sgn".  Two possible defs of
  1404 sgn are given as equational assumptions in the classes sgn_if and
  1405 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1406 INCOMPATIBILITY.
  1407 
  1408 * Locale "partial_order" now unified with class "order" (cf. theory
  1409 Orderings), added parameter "less".  INCOMPATIBILITY.
  1410 
  1411 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1412 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1413 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1414 
  1415 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1416 changed order of proof goals in instance proofs.
  1417 
  1418 * The transitivity reasoner for partial and linear orders is set up
  1419 for classes "order" and "linorder".  Instances of the reasoner are available
  1420 in all contexts importing or interpreting the corresponding locales.
  1421 Method "order" invokes the reasoner separately; the reasoner
  1422 is also integrated with the Simplifier as a solver.  Diagnostic
  1423 command 'print_orders' shows the available instances of the reasoner
  1424 in the current context.
  1425 
  1426 * Localized monotonicity predicate in theory "Orderings"; integrated
  1427 lemmas max_of_mono and min_of_mono with this predicate.
  1428 INCOMPATIBILITY.
  1429 
  1430 * Formulation of theorem "dense" changed slightly due to integration
  1431 with new class dense_linear_order.
  1432 
  1433 * Uniform lattice theory development in HOL.
  1434 
  1435     constants "meet" and "join" now named "inf" and "sup"
  1436     constant "Meet" now named "Inf"
  1437 
  1438     classes "meet_semilorder" and "join_semilorder" now named
  1439       "lower_semilattice" and "upper_semilattice"
  1440     class "lorder" now named "lattice"
  1441     class "comp_lat" now named "complete_lattice"
  1442 
  1443     Instantiation of lattice classes allows explicit definitions
  1444     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1445 
  1446   INCOMPATIBILITY.  Theorem renames:
  1447 
  1448     meet_left_le            ~> inf_le1
  1449     meet_right_le           ~> inf_le2
  1450     join_left_le            ~> sup_ge1
  1451     join_right_le           ~> sup_ge2
  1452     meet_join_le            ~> inf_sup_ord
  1453     le_meetI                ~> le_infI
  1454     join_leI                ~> le_supI
  1455     le_meet                 ~> le_inf_iff
  1456     le_join                 ~> ge_sup_conv
  1457     meet_idempotent         ~> inf_idem
  1458     join_idempotent         ~> sup_idem
  1459     meet_comm               ~> inf_commute
  1460     join_comm               ~> sup_commute
  1461     meet_leI1               ~> le_infI1
  1462     meet_leI2               ~> le_infI2
  1463     le_joinI1               ~> le_supI1
  1464     le_joinI2               ~> le_supI2
  1465     meet_assoc              ~> inf_assoc
  1466     join_assoc              ~> sup_assoc
  1467     meet_left_comm          ~> inf_left_commute
  1468     meet_left_idempotent    ~> inf_left_idem
  1469     join_left_comm          ~> sup_left_commute
  1470     join_left_idempotent    ~> sup_left_idem
  1471     meet_aci                ~> inf_aci
  1472     join_aci                ~> sup_aci
  1473     le_def_meet             ~> le_iff_inf
  1474     le_def_join             ~> le_iff_sup
  1475     join_absorp2            ~> sup_absorb2
  1476     join_absorp1            ~> sup_absorb1
  1477     meet_absorp1            ~> inf_absorb1
  1478     meet_absorp2            ~> inf_absorb2
  1479     meet_join_absorp        ~> inf_sup_absorb
  1480     join_meet_absorp        ~> sup_inf_absorb
  1481     distrib_join_le         ~> distrib_sup_le
  1482     distrib_meet_le         ~> distrib_inf_le
  1483 
  1484     add_meet_distrib_left   ~> add_inf_distrib_left
  1485     add_join_distrib_left   ~> add_sup_distrib_left
  1486     is_join_neg_meet        ~> is_join_neg_inf
  1487     is_meet_neg_join        ~> is_meet_neg_sup
  1488     add_meet_distrib_right  ~> add_inf_distrib_right
  1489     add_join_distrib_right  ~> add_sup_distrib_right
  1490     add_meet_join_distribs  ~> add_sup_inf_distribs
  1491     join_eq_neg_meet        ~> sup_eq_neg_inf
  1492     meet_eq_neg_join        ~> inf_eq_neg_sup
  1493     add_eq_meet_join        ~> add_eq_inf_sup
  1494     meet_0_imp_0            ~> inf_0_imp_0
  1495     join_0_imp_0            ~> sup_0_imp_0
  1496     meet_0_eq_0             ~> inf_0_eq_0
  1497     join_0_eq_0             ~> sup_0_eq_0
  1498     neg_meet_eq_join        ~> neg_inf_eq_sup
  1499     neg_join_eq_meet        ~> neg_sup_eq_inf
  1500     join_eq_if              ~> sup_eq_if
  1501 
  1502     mono_meet               ~> mono_inf
  1503     mono_join               ~> mono_sup
  1504     meet_bool_eq            ~> inf_bool_eq
  1505     join_bool_eq            ~> sup_bool_eq
  1506     meet_fun_eq             ~> inf_fun_eq
  1507     join_fun_eq             ~> sup_fun_eq
  1508     meet_set_eq             ~> inf_set_eq
  1509     join_set_eq             ~> sup_set_eq
  1510     meet1_iff               ~> inf1_iff
  1511     meet2_iff               ~> inf2_iff
  1512     meet1I                  ~> inf1I
  1513     meet2I                  ~> inf2I
  1514     meet1D1                 ~> inf1D1
  1515     meet2D1                 ~> inf2D1
  1516     meet1D2                 ~> inf1D2
  1517     meet2D2                 ~> inf2D2
  1518     meet1E                  ~> inf1E
  1519     meet2E                  ~> inf2E
  1520     join1_iff               ~> sup1_iff
  1521     join2_iff               ~> sup2_iff
  1522     join1I1                 ~> sup1I1
  1523     join2I1                 ~> sup2I1
  1524     join1I1                 ~> sup1I1
  1525     join2I2                 ~> sup1I2
  1526     join1CI                 ~> sup1CI
  1527     join2CI                 ~> sup2CI
  1528     join1E                  ~> sup1E
  1529     join2E                  ~> sup2E
  1530 
  1531     is_meet_Meet            ~> is_meet_Inf
  1532     Meet_bool_def           ~> Inf_bool_def
  1533     Meet_fun_def            ~> Inf_fun_def
  1534     Meet_greatest           ~> Inf_greatest
  1535     Meet_lower              ~> Inf_lower
  1536     Meet_set_def            ~> Inf_set_def
  1537 
  1538     Sup_def                 ~> Sup_Inf
  1539     Sup_bool_eq             ~> Sup_bool_def
  1540     Sup_fun_eq              ~> Sup_fun_def
  1541     Sup_set_eq              ~> Sup_set_def
  1542 
  1543     listsp_meetI            ~> listsp_infI
  1544     listsp_meet_eq          ~> listsp_inf_eq
  1545 
  1546     meet_min                ~> inf_min
  1547     join_max                ~> sup_max
  1548 
  1549 * Added syntactic class "size"; overloaded constant "size" now has
  1550 type "'a::size ==> bool"
  1551 
  1552 * Internal reorganisation of `size' of datatypes: size theorems
  1553 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1554 simplification rules by default!); theorems "prod.size" now named
  1555 "*.size".
  1556 
  1557 * Class "div" now inherits from class "times" rather than "type".
  1558 INCOMPATIBILITY.
  1559 
  1560 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1561 Linorder etc.  have disappeared; operations defined in terms of
  1562 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1563 
  1564 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1565 
  1566 * HOL-Word: New extensive library and type for generic, fixed size
  1567 machine words, with arithemtic, bit-wise, shifting and rotating
  1568 operations, reflection into int, nat, and bool lists, automation for
  1569 linear arithmetic (by automatic reflection into nat or int), including
  1570 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1571 arithmetic type classes, supporting automatic simplification of
  1572 numerals on all operations.
  1573 
  1574 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1575 
  1576 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1577 
  1578 * Code generator library theories:
  1579   - Code_Integer represents HOL integers by big integer literals in target
  1580     languages.
  1581   - Code_Char represents HOL characters by character literals in target
  1582     languages.
  1583   - Code_Char_chr like Code_Char, but also offers treatment of character
  1584     codes; includes Code_Integer.
  1585   - Executable_Set allows to generate code for finite sets using lists.
  1586   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1587     denominator).
  1588   - Executable_Real implements a subset of real numbers, namly those
  1589     representable by rational numbers.
  1590   - Efficient_Nat implements natural numbers by integers, which in general will
  1591     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1592     includes Code_Integer.
  1593   - Code_Index provides an additional datatype index which is mapped to
  1594     target-language built-in integers.
  1595   - Code_Message provides an additional datatype message_string which is isomorphic to
  1596     strings; messages are mapped to target-language strings.
  1597 
  1598 * New package for inductive predicates
  1599 
  1600   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1601 
  1602     inductive
  1603       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1604       for z_1 :: U_1 and ... and z_n :: U_m
  1605     where
  1606       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1607     | ...
  1608 
  1609   with full support for type-inference, rather than
  1610 
  1611     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1612 
  1613     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1614     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1615 
  1616     inductive "s z_1 ... z_m"
  1617     intros
  1618       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1619       ...
  1620 
  1621   For backward compatibility, there is a wrapper allowing inductive
  1622   sets to be defined with the new package via
  1623 
  1624     inductive_set
  1625       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1626       for z_1 :: U_1 and ... and z_n :: U_m
  1627     where
  1628       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1629     | ...
  1630 
  1631   or
  1632 
  1633     inductive_set
  1634       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1635       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1636       for z_1 :: U_1 and ... and z_n :: U_m
  1637     where
  1638       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1639     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1640     | ...
  1641 
  1642   if the additional syntax "p ..." is required.
  1643 
  1644   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1645   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1646 
  1647   INCOMPATIBILITIES:
  1648 
  1649   - Since declaration and definition of inductive sets or predicates
  1650     is no longer separated, abbreviations involving the newly
  1651     introduced sets or predicates must be specified together with the
  1652     introduction rules after the 'where' keyword (see above), rather
  1653     than before the actual inductive definition.
  1654 
  1655   - The variables in induction and elimination rules are now
  1656     quantified in the order of their occurrence in the introduction
  1657     rules, rather than in alphabetical order. Since this may break
  1658     some proofs, these proofs either have to be repaired, e.g. by
  1659     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1660     statements of the form
  1661 
  1662       case (rule_i a_i_1 ... a_i_{k_i})
  1663 
  1664     or the old order of quantification has to be restored by explicitly adding
  1665     meta-level quantifiers in the introduction rules, i.e.
  1666 
  1667       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1668 
  1669   - The format of the elimination rules is now
  1670 
  1671       p z_1 ... z_m x_1 ... x_n ==>
  1672         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1673         ==> ... ==> P
  1674 
  1675     for predicates and
  1676 
  1677       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1678         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1679         ==> ... ==> P
  1680 
  1681     for sets rather than
  1682 
  1683       x : s z_1 ... z_m ==>
  1684         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1685         ==> ... ==> P
  1686 
  1687     This may require terms in goals to be expanded to n-tuples
  1688     (e.g. using case_tac or simplification with the split_paired_all
  1689     rule) before the above elimination rule is applicable.
  1690 
  1691   - The elimination or case analysis rules for (mutually) inductive
  1692     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1693     list of rules "p_1_..._p_k.elims" is no longer available.
  1694 
  1695 * New package "function"/"fun" for general recursive functions,
  1696 supporting mutual and nested recursion, definitions in local contexts,
  1697 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1698 for small examples, and the separate tutorial on the function
  1699 package. The old recdef "package" is still available as before, but
  1700 users are encouraged to use the new package.
  1701 
  1702 * Method "lexicographic_order" automatically synthesizes termination
  1703 relations as lexicographic combinations of size measures. 
  1704 
  1705 * Case-expressions allow arbitrary constructor-patterns (including
  1706 "_") and take their order into account, like in functional
  1707 programming.  Internally, this is translated into nested
  1708 case-expressions; missing cases are added and mapped to the predefined
  1709 constant "undefined". In complicated cases printing may no longer show
  1710 the original input but the internal form. Lambda-abstractions allow
  1711 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1712 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1713 variable.
  1714 
  1715 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1716 is an abbreviation for "of_nat :: nat => int". The simplification
  1717 rules for "of_nat" have been changed to work like "int" did
  1718 previously.  Potential INCOMPATIBILITY:
  1719   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1720   - of_nat_diff and of_nat_mult are no longer default simp rules
  1721 
  1722 * Method "algebra" solves polynomial equations over (semi)rings using
  1723 Groebner bases. The (semi)ring structure is defined by locales and the
  1724 tool setup depends on that generic context. Installing the method for
  1725 a specific type involves instantiating the locale and possibly adding
  1726 declarations for computation on the coefficients.  The method is
  1727 already instantiated for natural numbers and for the axiomatic class
  1728 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1729 CALCULEMUS 2007 for the general principles underlying this
  1730 architecture of context-aware proof-tools.
  1731 
  1732 * Method "ferrack" implements quantifier elimination over
  1733 special-purpose dense linear orders using locales (analogous to
  1734 "algebra"). The method is already installed for class
  1735 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1736 rat, etc.
  1737 
  1738 * Former constant "List.op @" now named "List.append".  Use ML
  1739 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1740 circumvent possible incompatibilities when working on ML level.
  1741 
  1742 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1743 
  1744 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1745 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1746 
  1747 * New syntax for Haskell-like list comprehension (input only), eg.
  1748 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1749 
  1750 * The special syntax for function "filter" has changed from [x :
  1751 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1752 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1753 
  1754 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1755 defined on nat only, as an abbreviation for [a..<Suc b]
  1756 INCOMPATIBILITY.
  1757 
  1758 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1759 
  1760 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1761 
  1762 * New lemma collection field_simps (an extension of ring_simps) for
  1763 manipulating (in)equations involving division. Multiplies with all
  1764 denominators that can be proved to be non-zero (in equations) or
  1765 positive/negative (in inequations).
  1766 
  1767 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1768 have been improved and renamed to ring_simps, group_simps and
  1769 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1770 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1771 
  1772 * Theory Library/Commutative_Ring: switched from recdef to function
  1773 package; constants add, mul, pow now curried.  Infix syntax for
  1774 algebraic operations.
  1775 
  1776 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1777 INCOMPATIBILITY.
  1778 
  1779 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1780 INCOMPATIBILITY.
  1781 
  1782 * HOL/records: generalised field-update to take a function on the
  1783 field rather than the new value: r(|A := x|) is translated to A_update
  1784 (K x) r The K-combinator that is internally used is called K_record.
  1785 INCOMPATIBILITY: Usage of the plain update functions has to be
  1786 adapted.
  1787  
  1788 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1789 * x = 0, which are required for a semiring.  Richer structures do not
  1790 inherit from semiring_0 anymore, because this property is a theorem
  1791 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1792 there is more to prove, but this is mostly trivial.
  1793 
  1794 * Class "recpower" is generalized to arbitrary monoids, not just
  1795 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1796 commutativity or semiring properties additionally.
  1797 
  1798 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1799 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1800 better use 'abbreviation'.
  1801 
  1802 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1803 
  1804 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1805 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1806 significant changes for setting up numeral syntax for types:
  1807   - New constants Numeral.pred and Numeral.succ instead
  1808       of former Numeral.bin_pred and Numeral.bin_succ.
  1809   - Use integer operations instead of bin_add, bin_mult and so on.
  1810   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1811   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1812 
  1813 See src/HOL/Integ/IntArith.thy for an example setup.
  1814 
  1815 * Command 'normal_form' computes the normal form of a term that may
  1816 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1817 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1818 heavy-duty computations because the functions are compiled to ML
  1819 first.  Correspondingly, a method "normalization" is provided.  See
  1820 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1821 
  1822 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1823 25 like -->); output depends on the "iff" print_mode, the default is
  1824 "A = B" (with priority 50).
  1825 
  1826 * Relations less (<) and less_eq (<=) are also available on type bool.
  1827 Modified syntax to disallow nesting without explicit parentheses,
  1828 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1829 INCOMPATIBILITY.
  1830 
  1831 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1832 
  1833 * Relation composition operator "op O" now has precedence 75 and binds
  1834 stronger than union and intersection. INCOMPATIBILITY.
  1835 
  1836 * The old set interval syntax "{m..n(}" (and relatives) has been
  1837 removed.  Use "{m..<n}" (and relatives) instead.
  1838 
  1839 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1840 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1841 ``declare [[simproc del: neq]]''.
  1842 
  1843 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1844 True/False.
  1845 
  1846 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1847 
  1848 * Theorem setsum_mult renamed to setsum_right_distrib.
  1849 
  1850 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1851 ``rule'' method.
  1852 
  1853 * Reimplemented methods "sat" and "satx", with several improvements:
  1854 goals no longer need to be stated as "<prems> ==> False", equivalences
  1855 (i.e. "=" on type bool) are handled, variable names of the form
  1856 "lit_<n>" are no longer reserved, significant speedup.
  1857 
  1858 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1859 zChaff is still supported as well.
  1860 
  1861 * 'inductive' and 'datatype': provide projections of mutual rules,
  1862 bundled as foo_bar.inducts;
  1863 
  1864 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1865 Library.
  1866 
  1867 * Library: moved theory Accessible_Part to main HOL.
  1868 
  1869 * Library: added theory Coinductive_List of potentially infinite lists
  1870 as greatest fixed-point.
  1871 
  1872 * Library: added theory AssocList which implements (finite) maps as
  1873 association lists.
  1874 
  1875 * Method "evaluation" solves goals (i.e. a boolean expression)
  1876 efficiently by compiling it to ML.  The goal is "proved" (via an
  1877 oracle) if it evaluates to True.
  1878 
  1879 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1880 also when invoked by the simplifier.  This results in the Simplifier
  1881 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1882 Configuration option fast_arith_split_limit=0 recovers the old
  1883 behavior.
  1884 
  1885 * Support for hex (0x20) and binary (0b1001) numerals.
  1886 
  1887 * New method: reify eqs (t), where eqs are equations for an
  1888 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1889 parameter, computes a term s::'b and a list xs::'a list and proves the
  1890 theorem I xs s = t. This is also known as reification or quoting. The
  1891 resulting theorem is applied to the subgoal to substitute t with I xs
  1892 s.  If t is omitted, the subgoal itself is reified.
  1893 
  1894 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1895 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1896 where f is supposed to be a computable function (in the sense of code
  1897 generattion). The method uses reify to compute s and xs as above then
  1898 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1899 r and finally gets the theorem t = r, which is again applied to the
  1900 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1901 
  1902 * Reflection: Automatic reification now handels binding, an example is
  1903 available in src/HOL/ex/ReflectionEx.thy
  1904 
  1905 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1906 command 'statespace' that is similar to 'record', but introduces an
  1907 abstract specification based on the locale infrastructure instead of
  1908 HOL types.  This leads to extra flexibility in composing state spaces,
  1909 in particular multiple inheritance and renaming of components.
  1910 
  1911 
  1912 *** HOL-Complex ***
  1913 
  1914 * Hyperreal: Functions root and sqrt are now defined on negative real
  1915 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1916 Nonnegativity side conditions have been removed from many lemmas, so
  1917 that more subgoals may now be solved by simplification; potential
  1918 INCOMPATIBILITY.
  1919 
  1920 * Real: new type classes formalize real normed vector spaces and
  1921 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1922 and norm :: 'a => real.
  1923 
  1924 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1925 reals into other types. The overloaded constant Reals :: 'a set is now
  1926 defined as range of_real; potential INCOMPATIBILITY.
  1927 
  1928 * Real: proper support for ML code generation, including 'quickcheck'.
  1929 Reals are implemented as arbitrary precision rationals.
  1930 
  1931 * Hyperreal: Several constants that previously worked only for the
  1932 reals have been generalized, so they now work over arbitrary vector
  1933 spaces. Type annotations may need to be added in some cases; potential
  1934 INCOMPATIBILITY.
  1935 
  1936   Infinitesimal  :: ('a::real_normed_vector) star set
  1937   HFinite        :: ('a::real_normed_vector) star set
  1938   HInfinite      :: ('a::real_normed_vector) star set
  1939   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1940   monad          :: ('a::real_normed_vector) star => 'a star set
  1941   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1942   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1943   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1944   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1945   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1946   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1947   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1948   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1949   sgn            :: 'a::real_normed_vector => 'a
  1950   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1951 
  1952 * Complex: Some complex-specific constants are now abbreviations for
  1953 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1954 hnorm.  Other constants have been entirely removed in favor of the
  1955 polymorphic versions (INCOMPATIBILITY):
  1956 
  1957   approx        <-- capprox
  1958   HFinite       <-- CFinite
  1959   HInfinite     <-- CInfinite
  1960   Infinitesimal <-- CInfinitesimal
  1961   monad         <-- cmonad
  1962   galaxy        <-- cgalaxy
  1963   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1964   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1965   (ns)deriv     <-- (ns)cderiv
  1966 
  1967 
  1968 *** HOL-Algebra ***
  1969 
  1970 * Formalisation of ideals and the quotient construction over rings.
  1971 
  1972 * Order and lattice theory no longer based on records.
  1973 INCOMPATIBILITY.
  1974 
  1975 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1976 greatest_closed.  INCOMPATIBILITY.
  1977 
  1978 * Method algebra is now set up via an attribute.  For examples see
  1979 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1980 of algebraic structures.
  1981 
  1982 * Renamed theory CRing to Ring.
  1983 
  1984 
  1985 *** HOL-Nominal ***
  1986 
  1987 * Substantial, yet incomplete support for nominal datatypes (binding
  1988 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1989 src/HOL/Nominal/Examples.  Prospective users should consult
  1990 http://isabelle.in.tum.de/nominal/
  1991 
  1992 
  1993 *** ML ***
  1994 
  1995 * ML basics: just one true type int, which coincides with IntInf.int
  1996 (even on SML/NJ).
  1997 
  1998 * ML within Isar: antiquotations allow to embed statically-checked
  1999 formal entities in the source, referring to the context available at
  2000 compile-time.  For example:
  2001 
  2002 ML {* @{sort "{zero,one}"} *}
  2003 ML {* @{typ "'a => 'b"} *}
  2004 ML {* @{term "%x. x"} *}
  2005 ML {* @{prop "x == y"} *}
  2006 ML {* @{ctyp "'a => 'b"} *}
  2007 ML {* @{cterm "%x. x"} *}
  2008 ML {* @{cprop "x == y"} *}
  2009 ML {* @{thm asm_rl} *}
  2010 ML {* @{thms asm_rl} *}
  2011 ML {* @{type_name c} *}
  2012 ML {* @{type_syntax c} *}
  2013 ML {* @{const_name c} *}
  2014 ML {* @{const_syntax c} *}
  2015 ML {* @{context} *}
  2016 ML {* @{theory} *}
  2017 ML {* @{theory Pure} *}
  2018 ML {* @{theory_ref} *}
  2019 ML {* @{theory_ref Pure} *}
  2020 ML {* @{simpset} *}
  2021 ML {* @{claset} *}
  2022 ML {* @{clasimpset} *}
  2023 
  2024 The same works for sources being ``used'' within an Isar context.
  2025 
  2026 * ML in Isar: improved error reporting; extra verbosity with
  2027 ML_Context.trace enabled.
  2028 
  2029 * Pure/General/table.ML: the join operations now works via exceptions
  2030 DUP/SAME instead of type option. This is simpler in simple cases, and
  2031 admits slightly more efficient complex applications.
  2032 
  2033 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2034 use Context.generic instead of just theory.
  2035 
  2036 * Pure: datatype Context.generic joins theory/Proof.context and
  2037 provides some facilities for code that works in either kind of
  2038 context, notably GenericDataFun for uniform theory and proof data.
  2039 
  2040 * Pure: simplified internal attribute type, which is now always
  2041 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2042 local (Proof.context) attributes have been discontinued, while
  2043 minimizing code duplication. Thm.rule_attribute and
  2044 Thm.declaration_attribute build canonical attributes; see also structure
  2045 Context for further operations on Context.generic, notably
  2046 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2047 declarations and definitions.
  2048 
  2049 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2050 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2051 init only required for impure data. INCOMPATIBILITY: empty really need
  2052 to be empty (no dependencies on theory content!)
  2053 
  2054 * Pure/kernel: consts certification ignores sort constraints given in
  2055 signature declarations. (This information is not relevant to the
  2056 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2057 potential INCOMPATIBILITY.
  2058 
  2059 * Pure: axiomatic type classes are now purely definitional, with
  2060 explicit proofs of class axioms and super class relations performed
  2061 internally. See Pure/axclass.ML for the main internal interfaces --
  2062 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2063 AxClass.axiomatize_class/classrel/arity supersede
  2064 Sign.add_classes/classrel/arities.
  2065 
  2066 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2067 global/local versions on theory vs. Proof.context have been
  2068 discontinued; Attrib.syntax and Method.syntax have been adapted
  2069 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2070 attributes, methods, etc.
  2071 
  2072 * Pure: several functions of signature "... -> theory -> theory * ..."
  2073 have been reoriented to "... -> theory -> ... * theory" in order to
  2074 allow natural usage in combination with the ||>, ||>>, |-> and
  2075 fold_map combinators.
  2076 
  2077 * Pure: official theorem names (closed derivations) and additional
  2078 comments (tags) are now strictly separate.  Name hints -- which are
  2079 maintained as tags -- may be attached any time without affecting the
  2080 derivation.
  2081 
  2082 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2083 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2084 achieve the old behaviour.
  2085 
  2086 * Pure: the "Goal" constant is now called "prop", supporting a
  2087 slightly more general idea of ``protecting'' meta-level rule
  2088 statements.
  2089 
  2090 * Pure: Logic.(un)varify only works in a global context, which is now
  2091 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2092 Logic.legacy_(un)varify as temporary workaround.
  2093 
  2094 * Pure: structure Name provides scalable operations for generating
  2095 internal variable names, notably Name.variants etc.  This replaces
  2096 some popular functions from term.ML:
  2097 
  2098   Term.variant		->  Name.variant
  2099   Term.variantlist	->  Name.variant_list
  2100   Term.invent_names	->  Name.invent_list
  2101 
  2102 Note that low-level renaming rarely occurs in new code -- operations
  2103 from structure Variable are used instead (see below).
  2104 
  2105 * Pure: structure Variable provides fundamental operations for proper
  2106 treatment of fixed/schematic variables in a context.  For example,
  2107 Variable.import introduces fixes for schematics of given facts and
  2108 Variable.export reverses the effect (up to renaming) -- this replaces
  2109 various freeze_thaw operations.
  2110 
  2111 * Pure: structure Goal provides simple interfaces for
  2112 init/conclude/finish and tactical prove operations (replacing former
  2113 Tactic.prove).  Goal.prove is the canonical way to prove results
  2114 within a given context; Goal.prove_global is a degraded version for
  2115 theory level goals, including a global Drule.standard.  Note that
  2116 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2117 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2118 in a locale context).
  2119 
  2120 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2121 and type checking (Syntax.check_term etc.), with common combinations
  2122 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2123 which are considered legacy and await removal.
  2124 
  2125 * Pure/Syntax: generic interfaces for type unchecking
  2126 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2127 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2128 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2129 available for convenience, but refer to the very same operations using
  2130 a mere theory instead of a full context.
  2131 
  2132 * Isar: simplified treatment of user-level errors, using exception
  2133 ERROR of string uniformly.  Function error now merely raises ERROR,
  2134 without any side effect on output channels.  The Isar toplevel takes
  2135 care of proper display of ERROR exceptions.  ML code may use plain
  2136 handle/can/try; cat_error may be used to concatenate errors like this:
  2137 
  2138   ... handle ERROR msg => cat_error msg "..."
  2139 
  2140 Toplevel ML code (run directly or through the Isar toplevel) may be
  2141 embedded into the Isar toplevel with exception display/debug like
  2142 this:
  2143 
  2144   Isar.toplevel (fn () => ...)
  2145 
  2146 INCOMPATIBILITY, removed special transform_error facilities, removed
  2147 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2148 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2149 -- use plain ERROR instead.
  2150 
  2151 * Isar: theory setup now has type (theory -> theory), instead of a
  2152 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2153 
  2154 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2155 ProofContext.debug/verbose flags.
  2156 
  2157 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2158 theory before entering a proof state.  Transactions now always see a
  2159 quasi-functional intermediate checkpoint, both in interactive and
  2160 batch mode.
  2161 
  2162 * Isar: simplified interfaces for outer syntax.  Renamed
  2163 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2164 OuterSyntax.add_parsers -- this functionality is now included in
  2165 OuterSyntax.command etc.  INCOMPATIBILITY.
  2166 
  2167 * Simplifier: the simpset of a running simplification process now
  2168 contains a proof context (cf. Simplifier.the_context), which is the
  2169 very context that the initial simpset has been retrieved from (by
  2170 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2171 (solver, looper etc.) may depend on arbitrary proof data.
  2172 
  2173 * Simplifier.inherit_context inherits the proof context (plus the
  2174 local bounds) of the current simplification process; any simproc
  2175 etc. that calls the Simplifier recursively should do this!  Removed
  2176 former Simplifier.inherit_bounds, which is already included here --
  2177 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2178 specify an explicit context using Simplifier.context/theory_context.
  2179 
  2180 * Simplifier/Classical Reasoner: more abstract interfaces
  2181 change_simpset/claset for modifying the simpset/claset reference of a
  2182 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2183 INCOMPATIBILITY.
  2184 
  2185 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2186 "Trueprop" etc.
  2187 
  2188 
  2189 *** System ***
  2190 
  2191 * settings: the default heap location within ISABELLE_HOME_USER now
  2192 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2193 Isabelle installations.
  2194 
  2195 * isabelle-process: option -S (secure mode) disables some critical
  2196 operations, notably runtime compilation and evaluation of ML source
  2197 code.
  2198 
  2199 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2200 
  2201 * Support for parallel execution, using native multicore support of
  2202 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2203 independent theories, according to the given theory header
  2204 specifications. The maximum number of worker threads is specified via
  2205 usedir option -M or the "max-threads" setting in Proof General. A
  2206 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2207 to 6 on a 8-core machine.  User-code needs to observe certain
  2208 guidelines for thread-safe programming, see appendix A in the Isar
  2209 Implementation manual.
  2210 
  2211 
  2212 
  2213 New in Isabelle2005 (October 2005)
  2214 ----------------------------------
  2215 
  2216 *** General ***
  2217 
  2218 * Theory headers: the new header syntax for Isar theories is
  2219 
  2220   theory <name>
  2221   imports <theory1> ... <theoryN>
  2222   uses <file1> ... <fileM>
  2223   begin
  2224 
  2225 where the 'uses' part is optional.  The previous syntax
  2226 
  2227   theory <name> = <theory1> + ... + <theoryN>:
  2228 
  2229 will disappear in the next release.  Use isatool fixheaders to convert
  2230 existing theory files.  Note that there is no change in ancient
  2231 non-Isar theories now, but these will disappear soon.
  2232 
  2233 * Theory loader: parent theories can now also be referred to via
  2234 relative and absolute paths.
  2235 
  2236 * Command 'find_theorems' searches for a list of criteria instead of a
  2237 list of constants. Known criteria are: intro, elim, dest, name:string,
  2238 simp:term, and any term. Criteria can be preceded by '-' to select
  2239 theorems that do not match. Intro, elim, dest select theorems that
  2240 match the current goal, name:s selects theorems whose fully qualified
  2241 name contain s, and simp:term selects all simplification rules whose
  2242 lhs match term.  Any other term is interpreted as pattern and selects
  2243 all theorems matching the pattern. Available in ProofGeneral under
  2244 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2245 
  2246   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2247 
  2248 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2249 matching the current goal as introduction rule and not having "HOL."
  2250 in their name (i.e. not being defined in theory HOL).
  2251 
  2252 * Command 'thms_containing' has been discontinued in favour of
  2253 'find_theorems'; INCOMPATIBILITY.
  2254 
  2255 * Communication with Proof General is now 8bit clean, which means that
  2256 Unicode text in UTF-8 encoding may be used within theory texts (both
  2257 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2258 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2259 
  2260   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2261   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2262 
  2263 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2264 Classical Reasoner.  Typical big applications run around 2 times
  2265 faster.
  2266 
  2267 
  2268 *** Document preparation ***
  2269 
  2270 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2271 of raw sources.  Only those symbols that do not require additional
  2272 LaTeX packages (depending on comments in isabellesym.sty) are
  2273 displayed properly, everything else is left verbatim.  isatool display
  2274 and isatool print are used as front ends (these are subject to the
  2275 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2276 
  2277 * Command tags control specific markup of certain regions of text,
  2278 notably folding and hiding.  Predefined tags include "theory" (for
  2279 theory begin and end), "proof" for proof commands, and "ML" for
  2280 commands involving ML code; the additional tags "visible" and
  2281 "invisible" are unused by default.  Users may give explicit tag
  2282 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2283 interpretation of tags is determined by the LaTeX job during document
  2284 preparation: see option -V of isatool usedir, or options -n and -t of
  2285 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2286 \isadroptag.
  2287 
  2288 Several document versions may be produced at the same time via isatool
  2289 usedir (the generated index.html will link all of them).  Typical
  2290 specifications include ''-V document=theory,proof,ML'' to present
  2291 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2292 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2293 these parts without any formal replacement text.  The Isabelle site
  2294 default settings produce ''document'' and ''outline'' versions as
  2295 specified above.
  2296 
  2297 * Several new antiquotations:
  2298 
  2299   @{term_type term} prints a term with its type annotated;
  2300 
  2301   @{typeof term} prints the type of a term;
  2302 
  2303   @{const const} is the same as @{term const}, but checks that the
  2304   argument is a known logical constant;
  2305 
  2306   @{term_style style term} and @{thm_style style thm} print a term or
  2307   theorem applying a "style" to it
  2308 
  2309   @{ML text}
  2310 
  2311 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2312 definitions, equations, inequations etc., 'concl' printing only the
  2313 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2314 to print the specified premise.  TermStyle.add_style provides an ML
  2315 interface for introducing further styles.  See also the "LaTeX Sugar"
  2316 document practical applications.  The ML antiquotation prints
  2317 type-checked ML expressions verbatim.
  2318 
  2319 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2320 and 'text' support optional locale specification '(in loc)', which
  2321 specifies the default context for interpreting antiquotations.  For
  2322 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2323 
  2324 * Option 'locale=NAME' of antiquotations specifies an alternative
  2325 context interpreting the subsequent argument.  For example: @{thm
  2326 [locale=lattice] inf_assoc}.
  2327 
  2328 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2329 a proof context.
  2330 
  2331 * Proper output of antiquotations for theory commands involving a
  2332 proof context (such as 'locale' or 'theorem (in loc) ...').
  2333 
  2334 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2335 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2336 
  2337 * isatool usedir: new option -C (default true) controls whether option
  2338 -D should include a copy of the original document directory; -C false
  2339 prevents unwanted effects such as copying of administrative CVS data.
  2340 
  2341 
  2342 *** Pure ***
  2343 
  2344 * Considerably improved version of 'constdefs' command.  Now performs
  2345 automatic type-inference of declared constants; additional support for
  2346 local structure declarations (cf. locales and HOL records), see also
  2347 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2348 sequential dependencies of definitions within a single 'constdefs'
  2349 section; moreover, the declared name needs to be an identifier.  If
  2350 all fails, consider to fall back on 'consts' and 'defs' separately.
  2351 
  2352 * Improved indexed syntax and implicit structures.  First of all,
  2353 indexed syntax provides a notational device for subscripted
  2354 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2355 expressions.  Secondly, in a local context with structure
  2356 declarations, number indexes \<^sub>n or the empty index (default
  2357 number 1) refer to a certain fixed variable implicitly; option
  2358 show_structs controls printing of implicit structures.  Typical
  2359 applications of these concepts involve record types and locales.
  2360 
  2361 * New command 'no_syntax' removes grammar declarations (and
  2362 translations) resulting from the given syntax specification, which is
  2363 interpreted in the same manner as for the 'syntax' command.
  2364 
  2365 * 'Advanced' translation functions (parse_translation etc.) may depend
  2366 on the signature of the theory context being presently used for
  2367 parsing/printing, see also isar-ref manual.
  2368 
  2369 * Improved 'oracle' command provides a type-safe interface to turn an
  2370 ML expression of type theory -> T -> term into a primitive rule of
  2371 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2372 is already included here); see also FOL/ex/IffExample.thy;
  2373 INCOMPATIBILITY.
  2374 
  2375 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2376 before); "cI" is no longer bound, use "c.intro" instead.
  2377 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2378 axclasses vs. locales.
  2379 
  2380 * Improved internal renaming of symbolic identifiers -- attach primes
  2381 instead of base 26 numbers.
  2382 
  2383 * New flag show_question_marks controls printing of leading question
  2384 marks in schematic variable names.
  2385 
  2386 * In schematic variable names, *any* symbol following \<^isub> or
  2387 \<^isup> is now treated as part of the base name.  For example, the
  2388 following works without printing of awkward ".0" indexes:
  2389 
  2390   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2391     by simp
  2392 
  2393 * Inner syntax includes (*(*nested*) comments*).
  2394 
  2395 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2396 annotations as "(00...)".
  2397 
  2398 * Clear separation of logical types and nonterminals, where the latter
  2399 may only occur in 'syntax' specifications or type abbreviations.
  2400 Before that distinction was only partially implemented via type class
  2401 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2402 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2403 exotic syntax specifications may require further adaption
  2404 (e.g. Cube/Cube.thy).
  2405 
  2406 * Removed obsolete type class "logic", use the top sort {} instead.
  2407 Note that non-logical types should be declared as 'nonterminals'
  2408 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2409 specifications.
  2410 
  2411 * Attributes 'induct' and 'cases': type or set names may now be
  2412 locally fixed variables as well.
  2413 
  2414 * Simplifier: can now control the depth to which conditional rewriting
  2415 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2416 Limit.
  2417 
  2418 * Simplifier: simplification procedures may now take the current
  2419 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2420 interface), which is very useful for calling the Simplifier
  2421 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2422 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2423 low-level mk_simproc no longer applies Logic.varify internally, to
  2424 allow for use in a context of fixed variables.
  2425 
  2426 * thin_tac now works even if the assumption being deleted contains !!
  2427 or ==>.  More generally, erule now works even if the major premise of
  2428 the elimination rule contains !! or ==>.
  2429 
  2430 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2431 
  2432 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2433 from Pure, which contains all common declarations already.  Both
  2434 theories are defined via plain Isabelle/Isar .thy files.
  2435 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2436 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2437 use isatool fixcpure to adapt your theory and ML sources.
  2438 
  2439 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2440 selections of theorems in named facts via index ranges.
  2441 
  2442 * 'print_theorems': in theory mode, really print the difference
  2443 wrt. the last state (works for interactive theory development only),
  2444 in proof mode print all local facts (cf. 'print_facts');
  2445 
  2446 * 'hide': option '(open)' hides only base names.
  2447 
  2448 * More efficient treatment of intermediate checkpoints in interactive
  2449 theory development.
  2450 
  2451 * Code generator is now invoked via code_module (incremental code
  2452 generation) and code_library (modular code generation, ML structures
  2453 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2454 must be quoted when used as identifiers.
  2455 
  2456 * New 'value' command for reading, evaluating and printing terms using
  2457 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2458 quoted when used as identifier.
  2459 
  2460 
  2461 *** Locales ***
  2462 
  2463 * New commands for the interpretation of locale expressions in
  2464 theories (1), locales (2) and proof contexts (3).  These generate
  2465 proof obligations from the expression specification.  After the
  2466 obligations have been discharged, theorems of the expression are added
  2467 to the theory, target locale or proof context.  The synopsis of the
  2468 commands is a follows:
  2469 
  2470   (1) interpretation expr inst
  2471   (2) interpretation target < expr
  2472   (3) interpret expr inst
  2473 
  2474 Interpretation in theories and proof contexts require a parameter
  2475 instantiation of terms from the current context.  This is applied to
  2476 specifications and theorems of the interpreted expression.
  2477 Interpretation in locales only permits parameter renaming through the
  2478 locale expression.  Interpretation is smart in that interpretations
  2479 that are active already do not occur in proof obligations, neither are
  2480 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2481 inspect active interpretations of a particular locale.  For details,
  2482 see the Isar Reference manual.  Examples can be found in
  2483 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2484 
  2485 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2486 'interpret' instead.
  2487 
  2488 * New context element 'constrains' for adding type constraints to
  2489 parameters.
  2490 
  2491 * Context expressions: renaming of parameters with syntax
  2492 redeclaration.
  2493 
  2494 * Locale declaration: 'includes' disallowed.
  2495 
  2496 * Proper static binding of attribute syntax -- i.e. types / terms /
  2497 facts mentioned as arguments are always those of the locale definition
  2498 context, independently of the context of later invocations.  Moreover,
  2499 locale operations (renaming and type / term instantiation) are applied
  2500 to attribute arguments as expected.
  2501 
  2502 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2503 actual attributes; rare situations may require Attrib.attribute to
  2504 embed those attributes into Attrib.src that lack concrete syntax.
  2505 Attribute implementations need to cooperate properly with the static
  2506 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2507 Attrib.XXX_thm etc. already do the right thing without further
  2508 intervention.  Only unusual applications -- such as "where" or "of"
  2509 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2510 on the context and the facts involved -- may have to assign parsed
  2511 values to argument tokens explicitly.
  2512 
  2513 * Changed parameter management in theorem generation for long goal
  2514 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2515 theorem statement in rare situations.
  2516 
  2517 * Locale inspection command 'print_locale' omits notes elements.  Use
  2518 'print_locale!' to have them included in the output.
  2519 
  2520 
  2521 *** Provers ***
  2522 
  2523 * Provers/hypsubst.ML: improved version of the subst method, for
  2524 single-step rewriting: it now works in bound variable contexts. New is
  2525 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2526 rewrite a different subterm than the original subst method, which is
  2527 still available as 'simplesubst'.
  2528 
  2529 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2530 and quasi orders.
  2531 
  2532 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2533 reflexive-transitive closure of relations.
  2534 
  2535 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2536 limit (previously hard-coded with a value of 20) user-definable.
  2537 
  2538 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2539 is peformed already.  Object-logics merely need to finish their
  2540 initial simpset configuration as before.  INCOMPATIBILITY.
  2541 
  2542 
  2543 *** HOL ***
  2544 
  2545 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2546 
  2547   syntax (epsilon)
  2548     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2549 
  2550 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2551 and x-symbol; use option '-m epsilon' to get it actually printed.
  2552 Moreover, the mathematically important symbolic identifier \<epsilon>
  2553 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2554 
  2555 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2556 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2557 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2558 support corresponding Isar calculations.
  2559 
  2560 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2561 instead of ":".
  2562 
  2563 * theory SetInterval: changed the syntax for open intervals:
  2564 
  2565   Old       New
  2566   {..n(}    {..<n}
  2567   {)n..}    {n<..}
  2568   {m..n(}   {m..<n}
  2569   {)m..n}   {m<..n}
  2570   {)m..n(}  {m<..<n}
  2571 
  2572 The old syntax is still supported but will disappear in the next
  2573 release.  For conversion use the following Emacs search and replace
  2574 patterns (these are not perfect but work quite well):
  2575 
  2576   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2577   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2578 
  2579 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2580 equalities in commutative rings; method 'algebra' provides a generic
  2581 interface.
  2582 
  2583 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2584 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2585 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2586 be a tuple pattern.
  2587 
  2588 Some new syntax forms are available:
  2589 
  2590   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2591   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2592   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2593   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2594 
  2595 The latter form "\<Sum>x < k. e" used to be based on a separate
  2596 function "Summation", which has been discontinued.
  2597 
  2598 * theory Finite_Set: in structured induction proofs, the insert case
  2599 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2600 (insert F x)'.
  2601 
  2602 * The 'refute' command has been extended to support a much larger
  2603 fragment of HOL, including axiomatic type classes, constdefs and
  2604 typedefs, inductive datatypes and recursion.
  2605 
  2606 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2607 Requires zChaff with proof generation to be installed.  See
  2608 HOL/ex/SAT_Examples.thy for examples.
  2609 
  2610 * Datatype induction via method 'induct' now preserves the name of the
  2611 induction variable. For example, when proving P(xs::'a list) by
  2612 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2613 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2614 in unstructured proof scripts.
  2615 
  2616 * Reworked implementation of records.  Improved scalability for
  2617 records with many fields, avoiding performance problems for type
  2618 inference. Records are no longer composed of nested field types, but
  2619 of nested extension types. Therefore the record type only grows linear
  2620 in the number of extensions and not in the number of fields.  The
  2621 top-level (users) view on records is preserved.  Potential
  2622 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2623 old record representation. The type generated for a record is called
  2624 <record_name>_ext_type.
  2625 
  2626 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2627 proofs triggered by a record definition or a simproc (if
  2628 quick_and_dirty is enabled).  Definitions of large records can take
  2629 quite long.
  2630 
  2631 New simproc record_upd_simproc for simplification of multiple record
  2632 updates enabled by default.  Moreover, trivial updates are also
  2633 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2634 occasionally, since simplification is more powerful by default.
  2635 
  2636 * typedef: proper support for polymorphic sets, which contain extra
  2637 type-variables in the term.
  2638 
  2639 * Simplifier: automatically reasons about transitivity chains
  2640 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2641 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2642 old proofs break occasionally as simplification may now solve more
  2643 goals than previously.
  2644 
  2645 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2646 present.  Works for all partial orders (class "order"), in particular
  2647 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2648 just like y <= x.
  2649 
  2650 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2651 bound variable or a constant then the let is unfolded.  Otherwise
  2652 first a is simplified to b, and then f b is simplified to g. If
  2653 possible we abstract b from g arriving at "let x = b in h x",
  2654 otherwise we unfold the let and arrive at g.  The simproc can be
  2655 enabled/disabled by the reference use_let_simproc.  Potential
  2656 INCOMPATIBILITY since simplification is more powerful by default.
  2657 
  2658 * Classical reasoning: the meson method now accepts theorems as arguments.
  2659 
  2660 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2661 jobs to provide advice on the provability of subgoals.
  2662 
  2663 * Theory OrderedGroup and Ring_and_Field: various additions and
  2664 improvements to faciliate calculations involving equalities and
  2665 inequalities.
  2666 
  2667 The following theorems have been eliminated or modified
  2668 (INCOMPATIBILITY):
  2669 
  2670   abs_eq             now named abs_of_nonneg
  2671   abs_of_ge_0        now named abs_of_nonneg
  2672   abs_minus_eq       now named abs_of_nonpos
  2673   imp_abs_id         now named abs_of_nonneg
  2674   imp_abs_neg_id     now named abs_of_nonpos
  2675   mult_pos           now named mult_pos_pos
  2676   mult_pos_le        now named mult_nonneg_nonneg
  2677   mult_pos_neg_le    now named mult_nonneg_nonpos
  2678   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2679   mult_neg           now named mult_neg_neg
  2680   mult_neg_le        now named mult_nonpos_nonpos
  2681 
  2682 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2683      
  2684      zero_le_square
  2685      not_square_less_zero 
  2686 
  2687   The following lemmas have been deleted from Real/RealPow:
  2688   
  2689      realpow_zero_zero
  2690      realpow_two
  2691      realpow_less
  2692      zero_le_power
  2693      realpow_two_le
  2694      abs_realpow_two
  2695      realpow_two_abs     
  2696 
  2697 * Theory Parity: added rules for simplifying exponents.
  2698 
  2699 * Theory List:
  2700 
  2701 The following theorems have been eliminated or modified
  2702 (INCOMPATIBILITY):
  2703 
  2704   list_all_Nil       now named list_all.simps(1)
  2705   list_all_Cons      now named list_all.simps(2)
  2706   list_all_conv      now named list_all_iff
  2707   set_mem_eq         now named mem_iff
  2708 
  2709 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2710 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2711 
  2712 
  2713 *** HOL-Complex ***
  2714 
  2715 * Theory RealDef: better support for embedding natural numbers and
  2716 integers in the reals.
  2717 
  2718 The following theorems have been eliminated or modified
  2719 (INCOMPATIBILITY):
  2720 
  2721   exp_ge_add_one_self  now requires no hypotheses
  2722   real_of_int_add      reversed direction of equality (use [symmetric])
  2723   real_of_int_minus    reversed direction of equality (use [symmetric])
  2724   real_of_int_diff     reversed direction of equality (use [symmetric])
  2725   real_of_int_mult     reversed direction of equality (use [symmetric])
  2726 
  2727 * Theory RComplete: expanded support for floor and ceiling functions.
  2728 
  2729 * Theory Ln is new, with properties of the natural logarithm
  2730 
  2731 * Hyperreal: There is a new type constructor "star" for making
  2732 nonstandard types.  The old type names are now type synonyms:
  2733 
  2734   hypreal = real star
  2735   hypnat = nat star
  2736   hcomplex = complex star
  2737 
  2738 * Hyperreal: Many groups of similarly-defined constants have been
  2739 replaced by polymorphic versions (INCOMPATIBILITY):
  2740 
  2741   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2742 
  2743   starset      <-- starsetNat, starsetC
  2744   *s*          <-- *sNat*, *sc*
  2745   starset_n    <-- starsetNat_n, starsetC_n
  2746   *sn*         <-- *sNatn*, *scn*
  2747   InternalSets <-- InternalNatSets, InternalCSets
  2748 
  2749   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2750   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2751   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2752   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2753   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2754 
  2755 * Hyperreal: Many type-specific theorems have been removed in favor of
  2756 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2757 
  2758   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2759   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2760   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2761   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2762   right_minus <-- hypreal_add_minus
  2763   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2764   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2765   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2766   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2767   mult_1_right <-- hcomplex_mult_one_right
  2768   mult_zero_left <-- hcomplex_mult_zero_left
  2769   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2770   right_distrib <-- hypnat_add_mult_distrib2
  2771   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2772   right_inverse <-- hypreal_mult_inverse
  2773   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2774   order_refl <-- {hypreal,hypnat}_le_refl
  2775   order_trans <-- {hypreal,hypnat}_le_trans
  2776   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2777   order_less_le <-- {hypreal,hypnat}_less_le
  2778   linorder_linear <-- {hypreal,hypnat}_le_linear
  2779   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2780   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2781   add_nonneg_nonneg <-- hypreal_le_add_order
  2782 
  2783 * Hyperreal: Separate theorems having to do with type-specific
  2784 versions of constants have been merged into theorems that apply to the
  2785 new polymorphic constants (INCOMPATIBILITY):
  2786 
  2787   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2788   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2789   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2790   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2791   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2792   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2793   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2794   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2795   STAR_diff <-- {STAR,STARC}_diff
  2796   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2797     STARC_hcomplex_of_complex}_image_subset
  2798   starset_n_Un <-- starset{Nat,C}_n_Un
  2799   starset_n_Int <-- starset{Nat,C}_n_Int
  2800   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2801   starset_n_diff <-- starset{Nat,C}_n_diff
  2802   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2803   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2804   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2805   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2806   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2807   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2808   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2809   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2810   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2811   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2812   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2813   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2814   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2815   starfun_diff <-- starfun{C,RC,CR}_diff
  2816   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2817   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2818   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2819   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2820   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2821   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2822   starfun_Id <-- starfunC_Id
  2823   starfun_approx <-- starfun{Nat,CR}_approx
  2824   starfun_capprox <-- starfun{C,RC}_capprox
  2825   starfun_abs <-- starfunNat_rabs
  2826   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2827   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2828   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2829   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2830   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2831   starfun_add_approx <-- starfunCR_add_approx
  2832   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2833   starfun_divide <-- starfun{C,CR,RC}_divide
  2834   starfun_n <-- starfun{Nat,C}_n
  2835   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2836   starfun_n_add <-- starfun{Nat,C}_n_add
  2837   starfun_n_add_minus <-- starfunNat_n_add_minus
  2838   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2839   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2840   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2841 
  2842   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2843   star_n_minus <-- {hypreal,hcomplex}_minus
  2844   star_n_diff <-- {hypreal,hcomplex}_diff
  2845   star_n_mult <-- {hypreal,hcomplex}_mult
  2846   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2847   star_n_le <-- {hypreal,hypnat}_le
  2848   star_n_less <-- {hypreal,hypnat}_less
  2849   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2850   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2851   star_n_abs <-- hypreal_hrabs
  2852   star_n_divide <-- hcomplex_divide
  2853 
  2854   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2855   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2856   star_of_diff <-- hypreal_of_real_diff
  2857   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2858   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2859   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2860   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2861   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2862   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2863   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2864   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2865   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2866   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2867   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2868   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2869   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2870   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2871   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2872   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2873   star_of_power <-- hypreal_of_real_power
  2874   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2875 
  2876 * Hyperreal: new method "transfer" that implements the transfer
  2877 principle of nonstandard analysis. With a subgoal that mentions
  2878 nonstandard types like "'a star", the command "apply transfer"
  2879 replaces it with an equivalent one that mentions only standard types.
  2880 To be successful, all free variables must have standard types; non-
  2881 standard variables must have explicit universal quantifiers.
  2882 
  2883 * Hyperreal: A theory of Taylor series.
  2884 
  2885 
  2886 *** HOLCF ***
  2887 
  2888 * Discontinued special version of 'constdefs' (which used to support
  2889 continuous functions) in favor of the general Pure one with full
  2890 type-inference.
  2891 
  2892 * New simplification procedure for solving continuity conditions; it
  2893 is much faster on terms with many nested lambda abstractions (cubic
  2894 instead of exponential time).
  2895 
  2896 * New syntax for domain package: selector names are now optional.
  2897 Parentheses should be omitted unless argument is lazy, for example:
  2898 
  2899   domain 'a stream = cons "'a" (lazy "'a stream")
  2900 
  2901 * New command 'fixrec' for defining recursive functions with pattern
  2902 matching; defining multiple functions with mutual recursion is also
  2903 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2904 sinr, or any data constructor defined by the domain package. The given
  2905 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2906 syntax and examples.
  2907 
  2908 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2909 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2910 but the proof obligation additionally includes an admissibility
  2911 requirement. The packages generate instances of class cpo or pcpo,
  2912 with continuity and strictness theorems for Rep and Abs.
  2913 
  2914 * HOLCF: Many theorems have been renamed according to a more standard naming
  2915 scheme (INCOMPATIBILITY):
  2916 
  2917   foo_inject:  "foo$x = foo$y ==> x = y"
  2918   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2919   foo_less:    "(foo$x << foo$y) = (x << y)"
  2920   foo_strict:  "foo$UU = UU"
  2921   foo_defined: "... ==> foo$x ~= UU"
  2922   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2923 
  2924 
  2925 *** ZF ***
  2926 
  2927 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2928 including the First Isomorphism Theorem (on quotienting by the kernel
  2929 of a homomorphism).
  2930 
  2931 * ZF/Simplifier: install second copy of type solver that actually
  2932 makes use of TC rules declared to Isar proof contexts (or locales);
  2933 the old version is still required for ML proof scripts.
  2934 
  2935 
  2936 *** Cube ***
  2937 
  2938 * Converted to Isar theory format; use locales instead of axiomatic
  2939 theories.
  2940 
  2941 
  2942 *** ML ***
  2943 
  2944 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2945 for ||>, ||>>, |>>,
  2946 
  2947 * Pure/library.ML no longer defines its own option datatype, but uses
  2948 that of the SML basis, which has constructors NONE and SOME instead of
  2949 None and Some, as well as exception Option.Option instead of OPTION.
  2950 The functions the, if_none, is_some, is_none have been adapted
  2951 accordingly, while Option.map replaces apsome.
  2952 
  2953 * Pure/library.ML: the exception LIST has been given up in favour of
  2954 the standard exceptions Empty and Subscript, as well as
  2955 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2956 superceded by the standard hd and tl functions etc.
  2957 
  2958 A number of basic list functions are no longer exported to the ML
  2959 toplevel, as they are variants of predefined functions.  The following
  2960 suggests how one can translate existing code:
  2961 
  2962     rev_append xs ys = List.revAppend (xs, ys)
  2963     nth_elem (i, xs) = List.nth (xs, i)
  2964     last_elem xs = List.last xs
  2965     flat xss = List.concat xss
  2966     seq fs = List.app fs
  2967     partition P xs = List.partition P xs
  2968     mapfilter f xs = List.mapPartial f xs
  2969 
  2970 * Pure/library.ML: several combinators for linear functional
  2971 transformations, notably reverse application and composition:
  2972 
  2973   x |> f                f #> g
  2974   (x, y) |-> f          f #-> g
  2975 
  2976 * Pure/library.ML: introduced/changed precedence of infix operators:
  2977 
  2978   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2979   infix 2 ?;
  2980   infix 3 o oo ooo oooo;
  2981   infix 4 ~~ upto downto;
  2982 
  2983 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2984 infix operators.
  2985 
  2986 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2987 fold_map support linear functional transformations and nesting.  For
  2988 example:
  2989 
  2990   fold f [x1, ..., xN] y =
  2991     y |> f x1 |> ... |> f xN
  2992 
  2993   (fold o fold) f [xs1, ..., xsN] y =
  2994     y |> fold f xs1 |> ... |> fold f xsN
  2995 
  2996   fold f [x1, ..., xN] =
  2997     f x1 #> ... #> f xN
  2998 
  2999   (fold o fold) f [xs1, ..., xsN] =
  3000     fold f xs1 #> ... #> fold f xsN
  3001 
  3002 * Pure/library.ML: the following selectors on type 'a option are
  3003 available:
  3004 
  3005   the:               'a option -> 'a  (*partial*)
  3006   these:             'a option -> 'a  where 'a = 'b list
  3007   the_default: 'a -> 'a option -> 'a
  3008   the_list:          'a option -> 'a list
  3009 
  3010 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3011 basic operations for association lists, following natural argument
  3012 order; moreover the explicit equality predicate passed here avoids
  3013 potentially expensive polymorphic runtime equality checks.
  3014 The old functions may be expressed as follows:
  3015 
  3016   assoc = uncurry (AList.lookup (op =))
  3017   assocs = these oo AList.lookup (op =)
  3018   overwrite = uncurry (AList.update (op =)) o swap
  3019 
  3020 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3021 
  3022   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3023   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3024 
  3025 replacing make_keylist and keyfilter (occassionally used)
  3026 Naive rewrites:
  3027 
  3028   make_keylist = AList.make
  3029   keyfilter = AList.find (op =)
  3030 
  3031 * eq_fst and eq_snd now take explicit equality parameter, thus
  3032   avoiding eqtypes. Naive rewrites:
  3033 
  3034     eq_fst = eq_fst (op =)
  3035     eq_snd = eq_snd (op =)
  3036 
  3037 * Removed deprecated apl and apr (rarely used).
  3038   Naive rewrites:
  3039 
  3040     apl (n, op) =>>= curry op n
  3041     apr (op, m) =>>= fn n => op (n, m)
  3042 
  3043 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3044 provides a reasonably efficient light-weight implementation of sets as
  3045 lists.
  3046 
  3047 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3048 few new operations; existing lookup and update are now curried to
  3049 follow natural argument order (for use with fold etc.);
  3050 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3051 
  3052 * Pure/General: output via the Isabelle channels of
  3053 writeln/warning/error etc. is now passed through Output.output, with a
  3054 hook for arbitrary transformations depending on the print_mode
  3055 (cf. Output.add_mode -- the first active mode that provides a output
  3056 function wins).  Already formatted output may be embedded into further
  3057 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3058 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3059 accommodate easy composition of diagnostic messages etc.  Programmers
  3060 rarely need to care about Output.output or Output.raw at all, with
  3061 some notable exceptions: Output.output is required when bypassing the
  3062 standard channels (writeln etc.), or in token translations to produce
  3063 properly formatted results; Output.raw is required when capturing
  3064 already output material that will eventually be presented to the user
  3065 a second time.  For the default print mode, both Output.output and
  3066 Output.raw have no effect.
  3067 
  3068 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3069 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3070 cumulative results are displayed at the end of a batch session.
  3071 
  3072 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3073 replaced by File.platform_path and File.shell_path (with appropriate
  3074 hooks).  This provides a clean interface for unusual systems where the
  3075 internal and external process view of file names are different.
  3076 
  3077 * Pure: more efficient orders for basic syntactic entities: added
  3078 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3079 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3080 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3081 orders now -- potential INCOMPATIBILITY for code that depends on a
  3082 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3083 Library.sort_strings on result).
  3084 
  3085 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3086 fold_types traverse types/terms from left to right, observing natural
  3087 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3088 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3089 
  3090 * Pure: name spaces have been refined, with significant changes of the
  3091 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3092 to extern(_table).  The plain name entry path is superceded by a
  3093 general 'naming' context, which also includes the 'policy' to produce
  3094 a fully qualified name and external accesses of a fully qualified
  3095 name; NameSpace.extend is superceded by context dependent
  3096 Sign.declare_name.  Several theory and proof context operations modify
  3097 the naming context.  Especially note Theory.restore_naming and
  3098 ProofContext.restore_naming to get back to a sane state; note that
  3099 Theory.add_path is no longer sufficient to recover from
  3100 Theory.absolute_path in particular.
  3101 
  3102 * Pure: new flags short_names (default false) and unique_names
  3103 (default true) for controlling output of qualified names.  If
  3104 short_names is set, names are printed unqualified.  If unique_names is
  3105 reset, the name prefix is reduced to the minimum required to achieve
  3106 the original result when interning again, even if there is an overlap
  3107 with earlier declarations.
  3108 
  3109 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3110 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3111 (useful for printing error messages).  INCOMPATIBILITY.
  3112 
  3113 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3114 Theory.theory are now identified, referring to the universal
  3115 Context.theory (see Pure/context.ML).  Actual signature and theory
  3116 content is managed as theory data.  The old code and interfaces were
  3117 spread over many files and structures; the new arrangement introduces
  3118 considerable INCOMPATIBILITY to gain more clarity:
  3119 
  3120   Context -- theory management operations (name, identity, inclusion,
  3121     parents, ancestors, merge, etc.), plus generic theory data;
  3122 
  3123   Sign -- logical signature and syntax operations (declaring consts,
  3124     types, etc.), plus certify/read for common entities;
  3125 
  3126   Theory -- logical theory operations (stating axioms, definitions,
  3127     oracles), plus a copy of logical signature operations (consts,
  3128     types, etc.); also a few basic management operations (Theory.copy,
  3129     Theory.merge, etc.)
  3130 
  3131 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3132 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3133 for convenience -- they merely return the theory.
  3134 
  3135 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3136 
  3137 * Pure: the Isar proof context type is already defined early in Pure
  3138 as Context.proof (note that ProofContext.context and Proof.context are
  3139 aliases, where the latter is the preferred name).  This enables other
  3140 Isabelle components to refer to that type even before Isar is present.
  3141 
  3142 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3143 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3144 any of these kinds.  For example, Sign.intern typeK is now
  3145 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3146 Theory.hide_types.  Also note that former
  3147 Theory.hide_classes/types/consts are now
  3148 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3149 internalize their arguments!  INCOMPATIBILITY.
  3150 
  3151 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3152 datatype thmref (with constructors Name and NameSelection) instead of
  3153 plain string -- INCOMPATIBILITY;
  3154 
  3155 * Pure: cases produced by proof methods specify options, where NONE
  3156 means to remove case bindings -- INCOMPATIBILITY in
  3157 (RAW_)METHOD_CASES.
  3158 
  3159 * Pure: the following operations retrieve axioms or theorems from a
  3160 theory node or theory hierarchy, respectively:
  3161 
  3162   Theory.axioms_of: theory -> (string * term) list
  3163   Theory.all_axioms_of: theory -> (string * term) list
  3164   PureThy.thms_of: theory -> (string * thm) list
  3165   PureThy.all_thms_of: theory -> (string * thm) list
  3166 
  3167 * Pure: print_tac now outputs the goal through the trace channel.
  3168 
  3169 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3170 Reference Toplevel.debug (default false) controls detailed printing
  3171 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3172 controls execution profiling -- set to 1 for time and 2 for space
  3173 (both increase the runtime).
  3174 
  3175 * Isar session: The initial use of ROOT.ML is now always timed,
  3176 i.e. the log will show the actual process times, in contrast to the
  3177 elapsed wall-clock time that the outer shell wrapper produces.
  3178 
  3179 * Simplifier: improved handling of bound variables (nameless
  3180 representation, avoid allocating new strings).  Simprocs that invoke
  3181 the Simplifier recursively should use Simplifier.inherit_bounds to
  3182 avoid local name clashes.  Failure to do so produces warnings
  3183 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3184 for further details.
  3185 
  3186 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3187 bindings for all theorems stored within a given theory; this may help
  3188 in porting non-Isar theories to Isar ones, while keeping ML proof
  3189 scripts for the time being.
  3190 
  3191 * ML operator HTML.with_charset specifies the charset begin used for
  3192 generated HTML files.  For example:
  3193 
  3194   HTML.with_charset "utf-8" use_thy "Hebrew";
  3195   HTML.with_charset "utf-8" use_thy "Chinese";
  3196 
  3197 
  3198 *** System ***
  3199 
  3200 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3201 isabelle, isatool etc.).
  3202 
  3203 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3204 isatool doc, isatool mkdir, display_drafts etc.).
  3205 
  3206 * isatool usedir: option -f allows specification of the ML file to be
  3207 used by Isabelle; default is ROOT.ML.
  3208 
  3209 * New isatool version outputs the version identifier of the Isabelle
  3210 distribution being used.
  3211 
  3212 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3213 (containing Boolean satisfiability problems) into Isabelle/HOL
  3214 theories.
  3215 
  3216 
  3217 
  3218 New in Isabelle2004 (April 2004)
  3219 --------------------------------
  3220 
  3221 *** General ***
  3222 
  3223 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3224   Replaces linorder.ML.
  3225 
  3226 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3227   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3228   (\<a>...\<z>), are now considered normal letters, and can therefore
  3229   be used anywhere where an ASCII letter (a...zA...Z) has until
  3230   now. COMPATIBILITY: This obviously changes the parsing of some
  3231   terms, especially where a symbol has been used as a binder, say
  3232   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3233   as an identifier.  Fix it by inserting a space around former
  3234   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3235   existing theory and ML files.
  3236 
  3237 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3238 
  3239 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3240   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3241   a normal (but invisible) letter. For multiple letter subscripts repeat
  3242   \<^isub> like this: x\<^isub>1\<^isub>2.
  3243 
  3244 * Pure: There are now sub-/superscripts that can span more than one
  3245   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3246   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3247   superscript. The new control characters are not identifier parts.
  3248 
  3249 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3250   content of "..." to the latex file instead of \isacntrl... . The "..."
  3251   may consist of any printable characters excluding the end bracket >.
  3252 
  3253 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3254   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3255   declare constants "final", which prevents their being given a definition
  3256   later.  It is useful for constants whose behaviour is fixed axiomatically
  3257   rather than definitionally, such as the meta-logic connectives.
  3258 
  3259 * Pure: 'instance' now handles general arities with general sorts
  3260   (i.e. intersections of classes),
  3261 
  3262 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3263   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3264   It can be changed to alter the colors/layout of generated pages.
  3265 
  3266 
  3267 *** Isar ***
  3268 
  3269 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3270   cut_tac, subgoal_tac and thin_tac:
  3271   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3272     locales are no longer forced to write Isar proof scripts.
  3273     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3274     emulations.
  3275   - INCOMPATIBILITY: names of variables to be instantiated may no
  3276     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3277     This is consistent with the instantiation attribute "where".
  3278 
  3279 * Attributes "where" and "of":
  3280   - Now take type variables of instantiated theorem into account when reading
  3281     the instantiation string.  This fixes a bug that caused instantiated
  3282     theorems to have too special types in some circumstances.
  3283   - "where" permits explicit instantiations of type variables.
  3284 
  3285 * Calculation commands "moreover" and "also" no longer interfere with
  3286   current facts ("this"), admitting arbitrary combinations with "then"
  3287   and derived forms.
  3288 
  3289 * Locales:
  3290   - Goal statements involving the context element "includes" no longer
  3291     generate theorems with internal delta predicates (those ending on
  3292     "_axioms") in the premise.
  3293     Resolve particular premise with <locale>.intro to obtain old form.
  3294   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3295     specification and "includes" elements in goal statement.
  3296   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3297     [intro?] and [elim?] (respectively) by default.
  3298   - Experimental command for instantiation of locales in proof contexts:
  3299         instantiate <label>[<attrs>]: <loc>
  3300     Instantiates locale <loc> and adds all its theorems to the current context
  3301     taking into account their attributes.  Label and attrs are optional
  3302     modifiers, like in theorem declarations.  If present, names of
  3303     instantiated theorems are qualified with <label>, and the attributes
  3304     <attrs> are applied after any attributes these theorems might have already.
  3305       If the locale has assumptions, a chained fact of the form
  3306     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3307     are derived.  The command does not support old-style locales declared
  3308     with "locale (open)".
  3309       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3310 
  3311 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3312   (Isar) contexts.
  3313 
  3314 
  3315 *** HOL ***
  3316 
  3317 * Proof import: new image HOL4 contains the imported library from
  3318   the HOL4 system with about 2500 theorems. It is imported by
  3319   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3320   can be used like any other Isabelle image.  See
  3321   HOL/Import/HOL/README for more information.
  3322 
  3323 * Simplifier:
  3324   - Much improved handling of linear and partial orders.
  3325     Reasoners for linear and partial orders are set up for type classes
  3326     "linorder" and "order" respectively, and are added to the default simpset
  3327     as solvers.  This means that the simplifier can build transitivity chains
  3328     to solve goals from the assumptions.
  3329   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3330     of blast or auto after simplification become unnecessary because the goal
  3331     is solved by simplification already.
  3332 
  3333 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3334     all proved in axiomatic type classes for semirings, rings and fields.
  3335 
  3336 * Numerics:
  3337   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3338     now formalized using the Ring_and_Field theory mentioned above.
  3339   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3340     than before, because now they are set up once in a generic manner.
  3341   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3342     Look for the general versions in Ring_and_Field (and Power if they concern
  3343     exponentiation).
  3344 
  3345 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3346 
  3347 * Records:
  3348   - Record types are now by default printed with their type abbreviation
  3349     instead of the list of all field types. This can be configured via
  3350     the reference "print_record_type_abbr".
  3351   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3352     (not enabled by default).
  3353   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3354     EX x. x = sel r to True (not enabled by default).
  3355   - Tactic "record_split_simp_tac" to split and simplify records added.
  3356 
  3357 * 'specification' command added, allowing for definition by
  3358   specification.  There is also an 'ax_specification' command that
  3359   introduces the new constants axiomatically.
  3360 
  3361 * arith(_tac) is now able to generate counterexamples for reals as well.
  3362 
  3363 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3364 
  3365 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3366   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3367 
  3368 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3369   matrix theory to linear programming.
  3370 
  3371 * Unions and Intersections:
  3372   The latex output syntax of UN and INT has been changed
  3373   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3374   i.e. the index formulae has become a subscript.
  3375   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3376 
  3377 * Unions and Intersections over Intervals:
  3378   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3379   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3380   like in normal math, and corresponding versions for < and for intersection.
  3381 
  3382 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3383   lexicographic dictonary ordering has been added as "lexord".
  3384 
  3385 * ML: the legacy theory structures Int and List have been removed. They had
  3386   conflicted with ML Basis Library structures having the same names.
  3387 
  3388 * 'refute' command added to search for (finite) countermodels.  Only works
  3389   for a fragment of HOL.  The installation of an external SAT solver is
  3390   highly recommended.  See "HOL/Refute.thy" for details.
  3391 
  3392 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3393   formulae under an assignment of free variables to random values.
  3394   In contrast to 'refute', it can deal with inductive datatypes,
  3395   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3396   for examples.
  3397 
  3398 
  3399 *** HOLCF ***
  3400 
  3401 * Streams now come with concatenation and are part of the HOLCF image
  3402 
  3403 
  3404 
  3405 New in Isabelle2003 (May 2003)
  3406 ------------------------------
  3407 
  3408 *** General ***
  3409 
  3410 * Provers/simplifier:
  3411 
  3412   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3413     Assumptions are now subject to complete mutual simplification,
  3414     not just from left to right. The simplifier now preserves
  3415     the order of assumptions.
  3416 
  3417     Potential INCOMPATIBILITY:
  3418 
  3419     -- simp sometimes diverges where the old version did
  3420        not, e.g. invoking simp on the goal
  3421 
  3422         [| P (f x); y = x; f x = f y |] ==> Q
  3423 
  3424        now gives rise to the infinite reduction sequence
  3425 
  3426         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3427 
  3428        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3429        kind of problem.
  3430 
  3431     -- Tactics combining classical reasoner and simplification (such as auto)
  3432        are also affected by this change, because many of them rely on
  3433        simp. They may sometimes diverge as well or yield a different numbers
  3434        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3435        in case of problems. Sometimes subsequent calls to the classical
  3436        reasoner will fail because a preceeding call to the simplifier too
  3437        eagerly simplified the goal, e.g. deleted redundant premises.
  3438 
  3439   - The simplifier trace now shows the names of the applied rewrite rules
  3440 
  3441   - You can limit the number of recursive invocations of the simplifier
  3442     during conditional rewriting (where the simplifie tries to solve the
  3443     conditions before applying the rewrite rule):
  3444     ML "simp_depth_limit := n"
  3445     where n is an integer. Thus you can force termination where previously
  3446     the simplifier would diverge.
  3447 
  3448   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3449 
  3450   - No longer aborts on failed congruence proof.  Instead, the
  3451     congruence is ignored.
  3452 
  3453 * Pure: New generic framework for extracting programs from constructive
  3454   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3455   as HOL/Extraction for some case studies.
  3456 
  3457 * Pure: The main goal of the proof state is no longer shown by default, only
  3458 the subgoals. This behaviour is controlled by a new flag.
  3459    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3460 (ML: Proof.show_main_goal).
  3461 
  3462 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3463 rules whose conclusion matches subgoal 1:
  3464       PG menu: Isabelle/Isar -> Show me -> matching rules
  3465 The rules are ordered by how closely they match the subgoal.
  3466 In particular, rules that solve a subgoal outright are displayed first
  3467 (or rather last, the way they are printed).
  3468 (ML: ProofGeneral.print_intros())
  3469 
  3470 * Pure: New flag trace_unify_fail causes unification to print
  3471 diagnostic information (PG: in trace buffer) when it fails. This is
  3472 useful for figuring out why single step proofs like rule, erule or
  3473 assumption failed.
  3474 
  3475 * Pure: Locale specifications now produce predicate definitions
  3476 according to the body of text (covering assumptions modulo local
  3477 definitions); predicate "loc_axioms" covers newly introduced text,
  3478 while "loc" is cumulative wrt. all included locale expressions; the
  3479 latter view is presented only on export into the global theory
  3480 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3481 on the old view without predicates;
  3482 
  3483 * Pure: predefined locales "var" and "struct" are useful for sharing
  3484 parameters (as in CASL, for example); just specify something like
  3485 ``var x + var y + struct M'' as import;
  3486 
  3487 * Pure: improved thms_containing: proper indexing of facts instead of
  3488 raw theorems; check validity of results wrt. current name space;
  3489 include local facts of proof configuration (also covers active
  3490 locales), cover fixed variables in index; may use "_" in term
  3491 specification; an optional limit for the number of printed facts may
  3492 be given (the default is 40);
  3493 
  3494 * Pure: disallow duplicate fact bindings within new-style theory files
  3495 (batch-mode only);
  3496 
  3497 * Provers: improved induct method: assumptions introduced by case
  3498 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3499 the goal statement); "foo" still refers to all facts collectively;
  3500 
  3501 * Provers: the function blast.overloaded has been removed: all constants
  3502 are regarded as potentially overloaded, which improves robustness in exchange
  3503 for slight decrease in efficiency;
  3504 
  3505 * Provers/linorder: New generic prover for transitivity reasoning over
  3506 linear orders.  Note: this prover is not efficient!
  3507 
  3508 * Isar: preview of problems to finish 'show' now produce an error
  3509 rather than just a warning (in interactive mode);
  3510 
  3511 
  3512 *** HOL ***
  3513 
  3514 * arith(_tac)
  3515 
  3516  - Produces a counter example if it cannot prove a goal.
  3517    Note that the counter example may be spurious if the goal is not a formula
  3518    of quantifier-free linear arithmetic.
  3519    In ProofGeneral the counter example appears in the trace buffer.
  3520 
  3521  - Knows about div k and mod k where k is a numeral of type nat or int.
  3522 
  3523  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3524    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3525    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3526 
  3527 * simp's arithmetic capabilities have been enhanced a bit: it now
  3528 takes ~= in premises into account (by performing a case split);
  3529 
  3530 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3531 are distributed over a sum of terms;
  3532 
  3533 * New tactic "trans_tac" and method "trans" instantiate
  3534 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3535 "<=", "<" and "=").
  3536 
  3537 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3538 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3539 
  3540 * 'typedef' command has new option "open" to suppress the set
  3541 definition;
  3542 
  3543 * functions Min and Max on finite sets have been introduced (theory
  3544 Finite_Set);
  3545 
  3546 * attribute [symmetric] now works for relations as well; it turns
  3547 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3548 
  3549 * induct over a !!-quantified statement (say !!x1..xn):
  3550   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3551 
  3552 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3553 %x. None. Warning: empty_def now refers to the previously hidden definition
  3554 of the empty set.
  3555 
  3556 * Algebra: formalization of classical algebra.  Intended as base for
  3557 any algebraic development in Isabelle.  Currently covers group theory
  3558 (up to Sylow's theorem) and ring theory (Universal Property of
  3559 Univariate Polynomials).  Contributions welcome;
  3560 
  3561 * GroupTheory: deleted, since its material has been moved to Algebra;
  3562 
  3563 * Complex: new directory of the complex numbers with numeric constants,
  3564 nonstandard complex numbers, and some complex analysis, standard and
  3565 nonstandard (Jacques Fleuriot);
  3566 
  3567 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3568 
  3569 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3570 Fleuriot);
  3571 
  3572 * Real/HahnBanach: updated and adapted to locales;
  3573 
  3574 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3575 Gray and Kramer);
  3576 
  3577 * UNITY: added the Meier-Sanders theory of progress sets;
  3578 
  3579 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3580 as abstract algorithms, instantiated to the JVM;
  3581 
  3582 * Bali: Java source language formalization. Type system, operational
  3583 semantics, axiomatic semantics. Supported language features:
  3584 classes, interfaces, objects,virtual methods, static methods,
  3585 static/instance fields, arrays, access modifiers, definite
  3586 assignment, exceptions.
  3587 
  3588 
  3589 *** ZF ***
  3590 
  3591 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3592 universe, etc.);
  3593 
  3594 * Main ZF: virtually all theories converted to new-style format;
  3595 
  3596 
  3597 *** ML ***
  3598 
  3599 * Pure: Tactic.prove provides sane interface for internal proofs;
  3600 omits the infamous "standard" operation, so this is more appropriate
  3601 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3602 
  3603 * Pure: improved error reporting of simprocs;
  3604 
  3605 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3606 up simprocs;
  3607 
  3608 
  3609 *** Document preparation ***
  3610 
  3611 * uses \par instead of \\ for line breaks in theory text. This may
  3612 shift some page breaks in large documents. To get the old behaviour
  3613 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3614 
  3615 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3616 other packages
  3617 
  3618 * \<euro> now needs package babel/greek instead of marvosym (which
  3619 broke \Rightarrow)
  3620 
  3621 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3622 textcomp package)
  3623 
  3624 
  3625 
  3626 New in Isabelle2002 (March 2002)
  3627 --------------------------------
  3628 
  3629 *** Document preparation ***
  3630 
  3631 * greatly simplified document preparation setup, including more
  3632 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3633 instructive isatool mkdir; users should basically be able to get
  3634 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3635 users may run a separate document processing stage manually like this:
  3636 "isatool usedir -D output HOL Test && isatool document Test/output";
  3637 
  3638 * theory dependency graph may now be incorporated into documents;
  3639 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3640 with \includegraphics of LaTeX;
  3641 
  3642 * proper spacing of consecutive markup elements, especially text
  3643 blocks after section headings;
  3644 
  3645 * support bold style (for single symbols only), input syntax is like
  3646 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3647 
  3648 * \<bullet> is now output as bold \cdot by default, which looks much
  3649 better in printed text;
  3650 
  3651 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3652 note that these symbols are currently unavailable in Proof General /
  3653 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3654 
  3655 * isatool latex no longer depends on changed TEXINPUTS, instead
  3656 isatool document copies the Isabelle style files to the target
  3657 location;
  3658 
  3659 
  3660 *** Isar ***
  3661 
  3662 * Pure/Provers: improved proof by cases and induction;
  3663   - 'case' command admits impromptu naming of parameters (such as
  3664     "case (Suc n)");
  3665   - 'induct' method divinates rule instantiation from the inductive
  3666     claim; no longer requires excessive ?P bindings for proper
  3667     instantiation of cases;
  3668   - 'induct' method properly enumerates all possibilities of set/type
  3669     rules; as a consequence facts may be also passed through *type*
  3670     rules without further ado;
  3671   - 'induct' method now derives symbolic cases from the *rulified*
  3672     rule (before it used to rulify cases stemming from the internal
  3673     atomized version); this means that the context of a non-atomic
  3674     statement becomes is included in the hypothesis, avoiding the
  3675     slightly cumbersome show "PROP ?case" form;
  3676   - 'induct' may now use elim-style induction rules without chaining
  3677     facts, using ``missing'' premises from the goal state; this allows
  3678     rules stemming from inductive sets to be applied in unstructured
  3679     scripts, while still benefitting from proper handling of non-atomic
  3680     statements; NB: major inductive premises need to be put first, all
  3681     the rest of the goal is passed through the induction;
  3682   - 'induct' proper support for mutual induction involving non-atomic
  3683     rule statements (uses the new concept of simultaneous goals, see
  3684     below);
  3685   - append all possible rule selections, but only use the first
  3686     success (no backtracking);
  3687   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3688   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3689   - added 'print_induct_rules' (covered by help item in recent Proof
  3690     General versions);
  3691   - moved induct/cases attributes to Pure, methods to Provers;
  3692   - generic method setup instantiated for FOL and HOL;
  3693 
  3694 * Pure: support multiple simultaneous goal statements, for example
  3695 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3696 meta-level mechanism, this acts as if several individual goals had
  3697 been stated separately; in particular common proof methods need to be
  3698 repeated in order to cover all claims; note that a single elimination
  3699 step is *not* sufficient to establish the two conjunctions, so this
  3700 fails:
  3701 
  3702   assume "A & B" then have A and B ..   (*".." fails*)
  3703 
  3704 better use "obtain" in situations as above; alternative refer to
  3705 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3706 
  3707 * Pure: proper integration with ``locales''; unlike the original
  3708 version by Florian Kammller, Isar locales package high-level proof
  3709 contexts rather than raw logical ones (e.g. we admit to include
  3710 attributes everywhere); operations on locales include merge and
  3711 rename; support for implicit arguments (``structures''); simultaneous
  3712 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3713 some examples;
  3714 
  3715 * Pure: the following commands have been ``localized'', supporting a
  3716 target locale specification "(in name)": 'lemma', 'theorem',
  3717 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3718 stored both within the locale and at the theory level (exported and
  3719 qualified by the locale name);
  3720 
  3721 * Pure: theory goals may now be specified in ``long'' form, with
  3722 ad-hoc contexts consisting of arbitrary locale elements. for example
  3723 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3724 definitions may be given, too); the result is a meta-level rule with
  3725 the context elements being discharged in the obvious way;
  3726 
  3727 * Pure: new proof command 'using' allows to augment currently used
  3728 facts after a goal statement ('using' is syntactically analogous to
  3729 'apply', but acts on the goal's facts only); this allows chained facts
  3730 to be separated into parts given before and after a claim, as in
  3731 ``from a and b have C using d and e <proof>'';
  3732 
  3733 * Pure: renamed "antecedent" case to "rule_context";
  3734 
  3735 * Pure: new 'judgment' command records explicit information about the
  3736 object-logic embedding (used by several tools internally); no longer
  3737 use hard-wired "Trueprop";
  3738 
  3739 * Pure: added 'corollary' command;
  3740 
  3741 * Pure: fixed 'token_translation' command;
  3742 
  3743 * Pure: removed obsolete 'exported' attribute;
  3744 
  3745 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3746 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3747 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3748 
  3749 * Pure: method 'atomize' presents local goal premises as object-level
  3750 statements (atomic meta-level propositions); setup controlled via
  3751 rewrite rules declarations of 'atomize' attribute; example
  3752 application: 'induct' method with proper rule statements in improper
  3753 proof *scripts*;
  3754 
  3755 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3756 now consider the syntactic context of assumptions, giving a better
  3757 chance to get type-inference of the arguments right (this is
  3758 especially important for locales);
  3759 
  3760 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3761 mode;
  3762 
  3763 * Pure/obtain: the formal conclusion "thesis", being marked as
  3764 ``internal'', may no longer be reference directly in the text;
  3765 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3766 situations;
  3767 
  3768 * Pure: generic 'sym' attribute which declares a rule both as pure
  3769 'elim?' and for the 'symmetric' operation;
  3770 
  3771 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3772 text; the fixed correlation with particular command syntax has been
  3773 discontinued;
  3774 
  3775 * Pure: new method 'rules' is particularly well-suited for proof
  3776 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3777 but often produces more compact proof terms with less detours;
  3778 
  3779 * Pure/Provers/classical: simplified integration with pure rule
  3780 attributes and methods; the classical "intro?/elim?/dest?"
  3781 declarations coincide with the pure ones; the "rule" method no longer
  3782 includes classically swapped intros; "intro" and "elim" methods no
  3783 longer pick rules from the context; also got rid of ML declarations
  3784 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3785 INCOMPATIBILITY;
  3786 
  3787 * Provers/classical: attribute 'swapped' produces classical inversions
  3788 of introduction rules;
  3789 
  3790 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3791 rules instead of full simplifier context; 'iff' attribute handles
  3792 conditional rules;
  3793 
  3794 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3795 
  3796 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3797 "(permissive)" option to recover old behavior;
  3798 
  3799 * HOL: 'inductive' no longer features separate (collective) attributes
  3800 for 'intros' (was found too confusing);
  3801 
  3802 * HOL: properly declared induction rules less_induct and
  3803 wf_induct_rule;
  3804 
  3805 
  3806 *** HOL ***
  3807 
  3808 * HOL: moved over to sane numeral syntax; the new policy is as
  3809 follows:
  3810 
  3811   - 0 and 1 are polymorphic constants, which are defined on any
  3812   numeric type (nat, int, real etc.);
  3813 
  3814   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3815   binary representation internally;
  3816 
  3817   - type nat has special constructor Suc, and generally prefers Suc 0
  3818   over 1::nat and Suc (Suc 0) over 2::nat;
  3819 
  3820 This change may cause significant problems of INCOMPATIBILITY; here
  3821 are some hints on converting existing sources:
  3822 
  3823   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3824   entities, so expressions involving "-" (unary or binary minus) need
  3825   to be spaced properly;
  3826 
  3827   - existing occurrences of "1" may need to be constraint "1::nat" or
  3828   even replaced by Suc 0; similar for old "2";
  3829 
  3830   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3831 
  3832   - remove all special provisions on numerals in proofs;
  3833 
  3834 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3835 representation (depends on bin_arith_simps in the default context);
  3836 
  3837 * HOL: symbolic syntax for x^2 (numeral 2);
  3838 
  3839 * HOL: the class of all HOL types is now called "type" rather than
  3840 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3841 in axclass/classes, instance/arities, and (usually rare) occurrences
  3842 in typings (of consts etc.); internally the class is called
  3843 "HOL.type", ML programs should refer to HOLogic.typeS;
  3844 
  3845 * HOL/record package improvements:
  3846   - new derived operations "fields" to build a partial record section,
  3847     "extend" to promote a fixed record to a record scheme, and
  3848     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3849     declared as simp by default;
  3850   - shared operations ("more", "fields", etc.) now need to be always
  3851     qualified) --- potential INCOMPATIBILITY;
  3852   - removed "make_scheme" operations (use "make" with "extend") --
  3853     INCOMPATIBILITY;
  3854   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3855   - provides cases/induct rules for use with corresponding Isar
  3856     methods (for concrete records, record schemes, concrete more
  3857     parts, and schematic more parts -- in that order);
  3858   - internal definitions directly based on a light-weight abstract
  3859     theory of product types over typedef rather than datatype;
  3860 
  3861 * HOL: generic code generator for generating executable ML code from
  3862 specifications; specific support for HOL constructs such as inductive
  3863 datatypes and sets, as well as recursive functions; can be invoked
  3864 via 'generate_code' theory section;
  3865 
  3866 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3867 
  3868 * HOL: consolidated and renamed several theories.  In particular:
  3869         Ord.thy has been absorbed into HOL.thy
  3870         String.thy has been absorbed into List.thy
  3871 
  3872 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3873 (beware of argument permutation!);
  3874 
  3875 * HOL: linorder_less_split superseded by linorder_cases;
  3876 
  3877 * HOL/List: "nodups" renamed to "distinct";
  3878 
  3879 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3880 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3881   - Ex_def has changed, now need to use some_eq_ex
  3882 
  3883 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3884 in this (rare) case use:
  3885 
  3886   delSWrapper "split_all_tac"
  3887   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3888 
  3889 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3890 MAY FAIL;
  3891 
  3892 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3893 Isabelle's type classes, ^ on functions and relations has too general
  3894 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3895 necessary to attach explicit type constraints;
  3896 
  3897 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3898 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3899 renamed accordingly (eg "compI" -> "rel_compI").
  3900 
  3901 * HOL: syntax translations now work properly with numerals and records
  3902 expressions;
  3903 
  3904 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3905 of "lam" -- INCOMPATIBILITY;
  3906 
  3907 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3908 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3909 renamed "Product_Type.unit";
  3910 
  3911 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3912 
  3913 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3914 the "cases" method);
  3915 
  3916 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3917 Florian Kammller);
  3918 
  3919 * HOL/IMP: updated and converted to new-style theory format; several
  3920 parts turned into readable document, with proper Isar proof texts and
  3921 some explanations (by Gerwin Klein);
  3922 
  3923 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3924 
  3925 * HOL-Hyperreal is now a logic image;
  3926 
  3927 
  3928 *** HOLCF ***
  3929 
  3930 * Isar: consts/constdefs supports mixfix syntax for continuous
  3931 operations;
  3932 
  3933 * Isar: domain package adapted to new-style theory format, e.g. see
  3934 HOLCF/ex/Dnat.thy;
  3935 
  3936 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3937 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3938 lift.induct_tac, always use UU instead of Undef;
  3939 
  3940 * HOLCF/IMP: updated and converted to new-style theory;
  3941 
  3942 
  3943 *** ZF ***
  3944 
  3945 * Isar: proper integration of logic-specific tools and packages,
  3946 including theory commands '(co)inductive', '(co)datatype',
  3947 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3948 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3949 
  3950 * theory Main no longer includes AC; for the Axiom of Choice, base
  3951 your theory on Main_ZFC;
  3952 
  3953 * the integer library now covers quotients and remainders, with many
  3954 laws relating division to addition, multiplication, etc.;
  3955 
  3956 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3957 typeless version of the formalism;
  3958 
  3959 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3960 format;
  3961 
  3962 * ZF/Induct: new directory for examples of inductive definitions,
  3963 including theory Multiset for multiset orderings; converted to
  3964 new-style theory format;
  3965 
  3966 * ZF: many new theorems about lists, ordinals, etc.;
  3967 
  3968 
  3969 *** General ***
  3970 
  3971 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3972 variable proof controls level of detail: 0 = no proofs (only oracle
  3973 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3974 also ref manual for further ML interfaces;
  3975 
  3976 * Pure/axclass: removed obsolete ML interface
  3977 goal_subclass/goal_arity;
  3978 
  3979 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3980 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3981 separate tokens, so expressions involving minus need to be spaced
  3982 properly;
  3983 
  3984 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3985 rather than "infixl" or "infixr";
  3986 
  3987 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3988 sort constraint specifications in type inference; e.g. "x::_::foo"
  3989 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3990 type variable);
  3991 
  3992 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3993 control output of nested => (types); the default behavior is
  3994 "type_brackets";
  3995 
  3996 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3997 tokens into AST constants;
  3998 
  3999 * Pure/syntax: prefer later declarations of translations and print
  4000 translation functions; potential INCOMPATIBILITY: need to reverse
  4001 multiple declarations for same syntax element constant;
  4002 
  4003 * Pure/show_hyps reset by default (in accordance to existing Isar
  4004 practice);
  4005 
  4006 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4007 addSafter;
  4008 
  4009 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4010 as well;
  4011 
  4012 * system: tested support for MacOS X; should be able to get Isabelle +
  4013 Proof General to work in a plain Terminal after installing Poly/ML
  4014 (e.g. from the Isabelle distribution area) and GNU bash alone
  4015 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4016 support requires further installations, e.g. from
  4017 http://fink.sourceforge.net/);
  4018 
  4019 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4020 
  4021 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4022 of 40 MB), cf. ML_OPTIONS;
  4023 
  4024 * system: Proof General keywords specification is now part of the
  4025 Isabelle distribution (see etc/isar-keywords.el);
  4026 
  4027 * system: support for persistent Proof General sessions (refrain from
  4028 outdating all loaded theories on startup); user may create writable
  4029 logic images like this: ``isabelle -q HOL Test'';
  4030 
  4031 * system: smart selection of Isabelle process versus Isabelle
  4032 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4033 run both "isabelle" and "Isabelle" even if file names are badly
  4034 damaged (executable inspects the case of the first letter of its own
  4035 name); added separate "isabelle-process" and "isabelle-interface";
  4036 
  4037 * system: refrain from any attempt at filtering input streams; no
  4038 longer support ``8bit'' encoding of old isabelle font, instead proper
  4039 iso-latin characters may now be used; the related isatools
  4040 "symbolinput" and "nonascii" have disappeared as well;
  4041 
  4042 * system: removed old "xterm" interface (the print modes "xterm" and
  4043 "xterm_color" are still available for direct use in a suitable
  4044 terminal);
  4045 
  4046 
  4047 
  4048 New in Isabelle99-2 (February 2001)
  4049 -----------------------------------
  4050 
  4051 *** Overview of INCOMPATIBILITIES ***
  4052 
  4053 * HOL: please note that theories in the Library and elsewhere often use the
  4054 new-style (Isar) format; to refer to their theorems in an ML script you must
  4055 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4056 
  4057 * HOL: inductive package no longer splits induction rule aggressively,
  4058 but only as far as specified by the introductions given; the old
  4059 format may be recovered via ML function complete_split_rule or attribute
  4060 'split_rule (complete)';
  4061 
  4062 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4063 gfp_Tarski to gfp_unfold;
  4064 
  4065 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4066 
  4067 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4068 relation); infix "^^" has been renamed "``"; infix "``" has been
  4069 renamed "`"; "univalent" has been renamed "single_valued";
  4070 
  4071 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4072 operation;
  4073 
  4074 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4075 
  4076 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4077 
  4078 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4079 consequence, it is no longer monotonic wrt. the local goal context
  4080 (which is now passed through the inductive cases);
  4081 
  4082 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4083 \<gg> to \<ggreater>;
  4084 
  4085 
  4086 *** Document preparation ***
  4087 
  4088 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4089 available: are "it" for near math-mode best-style output, "sl" for
  4090 slanted text style, and "tt" for plain type-writer; if no
  4091 \isabellestyle command is given, output is according to slanted
  4092 type-writer);
  4093 
  4094 * support sub/super scripts (for single symbols only), input syntax is
  4095 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4096 
  4097 * some more standard symbols; see Appendix A of the system manual for
  4098 the complete list of symbols defined in isabellesym.sty;
  4099 
  4100 * improved isabelle style files; more abstract symbol implementation
  4101 (should now use \isamath{...} and \isatext{...} in custom symbol
  4102 definitions);
  4103 
  4104 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4105 state; Note that presentation of goal states does not conform to
  4106 actual human-readable proof documents.  Please do not include goal
  4107 states into document output unless you really know what you are doing!
  4108 
  4109 * proper indentation of antiquoted output with proportional LaTeX
  4110 fonts;
  4111 
  4112 * no_document ML operator temporarily disables LaTeX document
  4113 generation;
  4114 
  4115 * isatool unsymbolize tunes sources for plain ASCII communication;
  4116 
  4117 
  4118 *** Isar ***
  4119 
  4120 * Pure: Isar now suffers initial goal statements to contain unbound
  4121 schematic variables (this does not conform to actual readable proof
  4122 documents, due to unpredictable outcome and non-compositional proof
  4123 checking); users who know what they are doing may use schematic goals
  4124 for Prolog-style synthesis of proven results;
  4125 
  4126 * Pure: assumption method (an implicit finishing) now handles actual
  4127 rules as well;
  4128 
  4129 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4130 initial goal, declare "that" only as Pure intro (only for single
  4131 steps); the "that" rule assumption may now be involved in implicit
  4132 finishing, thus ".." becomes a feasible for trivial obtains;
  4133 
  4134 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4135 instance proofs may be performed by "..";
  4136 
  4137 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4138 statements as well;
  4139 
  4140 * Pure: more robust selection of calculational rules;
  4141 
  4142 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4143 rule (as well as the assumption rule);
  4144 
  4145 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4146 lemmas, using the graph browser tool;
  4147 
  4148 * Pure: predict failure of "show" in interactive mode;
  4149 
  4150 * Pure: 'thms_containing' now takes actual terms as arguments;
  4151 
  4152 * HOL: improved method 'induct' --- now handles non-atomic goals
  4153 (potential INCOMPATIBILITY); tuned error handling;
  4154 
  4155 * HOL: cases and induct rules now provide explicit hints about the
  4156 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4157 any remaining facts are inserted into the goal verbatim;
  4158 
  4159 * HOL: local contexts (aka cases) may now contain term bindings as
  4160 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4161 the result to be shown in each case;
  4162 
  4163 * HOL: added 'recdef_tc' command;
  4164 
  4165 * isatool convert assists in eliminating legacy ML scripts;
  4166 
  4167 
  4168 *** HOL ***
  4169 
  4170 * HOL/Library: a collection of generic theories to be used together
  4171 with main HOL; the theory loader path already includes this directory
  4172 by default; the following existing theories have been moved here:
  4173 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4174 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4175 
  4176 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4177 modelling and verification task performed in Isabelle/HOL +
  4178 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4179 
  4180 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4181 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4182 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4183 'domain', this makes the theory consistent with mathematical
  4184 literature;
  4185 
  4186 * HOL basics: added overloaded operations "inverse" and "divide"
  4187 (infix "/"), syntax for generic "abs" operation, generic summation
  4188 operator \<Sum>;
  4189 
  4190 * HOL/typedef: simplified package, provide more useful rules (see also
  4191 HOL/subset.thy);
  4192 
  4193 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4194 now expressed as a proper nested rule (old-style tactic scripts may
  4195 require atomize_strip_tac to cope with non-atomic premises);
  4196 
  4197 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4198 to "split_conv" (old name still available for compatibility);
  4199 
  4200 * HOL: improved concrete syntax for strings (e.g. allows translation
  4201 rules with string literals);
  4202 
  4203 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4204  and Fleuriot's mechanization of analysis, including the transcendental
  4205  functions for the reals;
  4206 
  4207 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4208 
  4209 
  4210 *** CTT ***
  4211 
  4212 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4213 "lam" is displayed as TWO lambda-symbols
  4214 
  4215 * CTT: theory Main now available, containing everything (that is, Bool
  4216 and Arith);
  4217 
  4218 
  4219 *** General ***
  4220 
  4221 * Pure: the Simplifier has been implemented properly as a derived rule
  4222 outside of the actual kernel (at last!); the overall performance
  4223 penalty in practical applications is about 50%, while reliability of
  4224 the Isabelle inference kernel has been greatly improved;
  4225 
  4226 * print modes "brackets" and "no_brackets" control output of nested =>
  4227 (types) and ==> (props); the default behaviour is "brackets";
  4228 
  4229 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4230 as assumptions as well;
  4231 
  4232 * system: support Poly/ML 4.0;
  4233 
  4234 * system: isatool install handles KDE version 1 or 2;
  4235 
  4236 
  4237 
  4238 New in Isabelle99-1 (October 2000)
  4239 ----------------------------------
  4240 
  4241 *** Overview of INCOMPATIBILITIES ***
  4242 
  4243 * HOL: simplification of natural numbers is much changed; to partly
  4244 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4245 issue the following ML commands:
  4246 
  4247   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4248   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4249 
  4250 * HOL: simplification no longer dives into case-expressions; this is
  4251 controlled by "t.weak_case_cong" for each datatype t;
  4252 
  4253 * HOL: nat_less_induct renamed to less_induct;
  4254 
  4255 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4256 fixsome to patch .thy and .ML sources automatically;
  4257 
  4258   select_equality  -> some_equality
  4259   select_eq_Ex     -> some_eq_ex
  4260   selectI2EX       -> someI2_ex
  4261   selectI2         -> someI2
  4262   selectI          -> someI
  4263   select1_equality -> some1_equality
  4264   Eps_sym_eq       -> some_sym_eq_trivial
  4265   Eps_eq           -> some_eq_trivial
  4266 
  4267 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4268 
  4269 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4270 instead);
  4271 
  4272 * HOL: the recursion equations generated by 'recdef' are now called
  4273 f.simps instead of f.rules;
  4274 
  4275 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4276 
  4277 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4278 sometimes be needed;
  4279 
  4280 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4281 
  4282 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4283 
  4284 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4285 product is now "<*>" instead of "Times"; the lexicographic product is
  4286 now "<*lex*>" instead of "**";
  4287 
  4288 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4289 of main HOL, but was unused); better use HOL's datatype package;
  4290 
  4291 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4292 the old syntax may be recovered as follows:
  4293 
  4294   syntax (symbols)
  4295     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4296       (infixl "\\<oplus>" 100)
  4297 
  4298 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4299 
  4300 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4301 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4302 internally;
  4303 
  4304 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4305 changed from A/r to A//r;
  4306 
  4307 * ZF: new treatment of arithmetic (nat & int) may break some old
  4308 proofs;
  4309 
  4310 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4311 rulify -> rule_format, elimify -> elim_format, ...);
  4312 
  4313 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4314 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4315 should have to change intro!! to intro? only); replaced "delrule" by
  4316 "rule del";
  4317 
  4318 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4319 
  4320 * Provers: strengthened force_tac by using new first_best_tac;
  4321 
  4322 * LaTeX document preparation: several changes of isabelle.sty (see
  4323 lib/texinputs);
  4324 
  4325 
  4326 *** Document preparation ***
  4327 
  4328 * formal comments (text blocks etc.) in new-style theories may now
  4329 contain antiquotations of thm/prop/term/typ/text to be presented
  4330 according to latex print mode; concrete syntax is like this:
  4331 @{term[show_types] "f(x) = a + x"};
  4332 
  4333 * isatool mkdir provides easy setup of Isabelle session directories,
  4334 including proper document sources;
  4335 
  4336 * generated LaTeX sources are now deleted after successful run
  4337 (isatool document -c); may retain a copy somewhere else via -D option
  4338 of isatool usedir;
  4339 
  4340 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4341 style files, achieving self-contained LaTeX sources and simplifying
  4342 LaTeX debugging;
  4343 
  4344 * old-style theories now produce (crude) LaTeX output as well;
  4345 
  4346 * browser info session directories are now self-contained (may be put
  4347 on WWW server seperately); improved graphs of nested sessions; removed
  4348 graph for 'all sessions';
  4349 
  4350 * several improvements in isabelle style files; \isabellestyle{it}
  4351 produces fake math mode output; \isamarkupheader is now \section by
  4352 default; see lib/texinputs/isabelle.sty etc.;
  4353 
  4354 
  4355 *** Isar ***
  4356 
  4357 * Isar/Pure: local results and corresponding term bindings are now
  4358 subject to Hindley-Milner polymorphism (similar to ML); this
  4359 accommodates incremental type-inference very nicely;
  4360 
  4361 * Isar/Pure: new derived language element 'obtain' supports
  4362 generalized existence reasoning;
  4363 
  4364 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4365 support accumulation of results, without applying any rules yet;
  4366 useful to collect intermediate results without explicit name
  4367 references, and for use with transitivity rules with more than 2
  4368 premises;
  4369 
  4370 * Isar/Pure: scalable support for case-analysis type proofs: new
  4371 'case' language element refers to local contexts symbolically, as
  4372 produced by certain proof methods; internally, case names are attached
  4373 to theorems as "tags";
  4374 
  4375 * Isar/Pure: theory command 'hide' removes declarations from
  4376 class/type/const name spaces;
  4377 
  4378 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4379 indicate potential overloading;
  4380 
  4381 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4382 
  4383 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4384 "{a,b,c}" instead of {a,b,c};
  4385 
  4386 * Isar/Pure now provides its own version of intro/elim/dest
  4387 attributes; useful for building new logics, but beware of confusion
  4388 with the version in Provers/classical;
  4389 
  4390 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4391 case name 'antecedent';
  4392 
  4393 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4394 to the current context is now done automatically);
  4395 
  4396 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4397 for definining proof methods in ML;
  4398 
  4399 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4400 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4401 most cases, one should have to change intro!! to intro? only);
  4402 replaced "delrule" by "rule del";
  4403 
  4404 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4405 'symmetric' attribute (the latter supercedes [RS sym]);
  4406 
  4407 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4408 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4409 well (including splits);
  4410 
  4411 * Isar/Provers: Simplifier and Classical methods now support all kind
  4412 of modifiers used in the past, including 'cong', 'iff', etc.
  4413 
  4414 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4415 of Simplifier and Classical reasoner);
  4416 
  4417 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4418 now support named cases; major packages (inductive, datatype, primrec,
  4419 recdef) support case names and properly name parameters;
  4420 
  4421 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4422 monotonicity conditions are extracted to be proven at end of
  4423 calculations;
  4424 
  4425 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4426 method anyway;
  4427 
  4428 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4429 split_if split_if_asm; datatype package provides theorems foo.splits =
  4430 foo.split foo.split_asm for each datatype;
  4431 
  4432 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4433 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4434 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4435 use "(cases (simplified))" method in proper proof texts);
  4436 
  4437 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4438 
  4439 * Isar: names of theorems etc. may be natural numbers as well;
  4440 
  4441 * Isar: 'pr' command: optional arguments for goals_limit and
  4442 ProofContext.prems_limit; no longer prints theory contexts, but only
  4443 proof states;
  4444 
  4445 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4446 additional print modes to be specified; e.g. "pr(latex)" will print
  4447 proof state according to the Isabelle LaTeX style;
  4448 
  4449 * Isar: improved support for emulating tactic scripts, including proof
  4450 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4451 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4452 (for HOL datatypes);
  4453 
  4454 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4455 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4456 'proof method scripts' have to be in depth-first order;
  4457 
  4458 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4459 
  4460 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4461 should instead use individual commands for printing items
  4462 (print_commands, print_methods etc.);
  4463 
  4464 * Isar: added 'nothing' --- the empty list of theorems;
  4465 
  4466 
  4467 *** HOL ***
  4468 
  4469 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4470 corresponding virtual machine and a specification of its bytecode
  4471 verifier and a lightweight bytecode verifier, including proofs of
  4472 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4473 Cornelia Pusch (see also the homepage of project Bali at
  4474 http://isabelle.in.tum.de/Bali/);
  4475 
  4476 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4477 Clemens Ballarin;
  4478 
  4479 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4480 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4481 Rasmussen;
  4482 
  4483 * HOL/Lattice: fundamental concepts of lattice theory and order
  4484 structures, including duals, properties of bounds versus algebraic
  4485 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4486 Theorem for complete lattices etc.; may also serve as a demonstration
  4487 for abstract algebraic reasoning using axiomatic type classes, and
  4488 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4489 
  4490 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4491 von Oheimb;
  4492 
  4493 * HOL/IMPP: extension of IMP with local variables and mutually
  4494 recursive procedures, by David von Oheimb;
  4495 
  4496 * HOL/Lambda: converted into new-style theory and document;
  4497 
  4498 * HOL/ex/Multiquote: example of multiple nested quotations and
  4499 anti-quotations -- basically a generalized version of de-Bruijn
  4500 representation; very useful in avoiding lifting of operations;
  4501 
  4502 * HOL/record: added general record equality rule to simpset; fixed
  4503 select-update simplification procedure to handle extended records as
  4504 well; admit "r" as field name;
  4505 
  4506 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4507 other numeric types and also as the identity of groups, rings, etc.;
  4508 
  4509 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4510 Types nat and int belong to this axclass;
  4511 
  4512 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4513    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4514    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4515   two terms #m*u and #n*u are replaced by #(m+n)*u
  4516     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4517   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4518     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4519 
  4520 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4521 powerful prover for predicate logic but knows nothing of clasets; see
  4522 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4523 
  4524 * HOL: new version of "case_tac" subsumes both boolean case split and
  4525 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4526 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4527 
  4528 * HOL: simplification no longer dives into case-expressions: only the
  4529 selector expression is simplified, but not the remaining arms; to
  4530 enable full simplification of case-expressions for datatype t, you may
  4531 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4532 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4533 
  4534 * HOL/recdef: the recursion equations generated by 'recdef' for
  4535 function 'f' are now called f.simps instead of f.rules; if all
  4536 termination conditions are proved automatically, these simplification
  4537 rules are added to the simpset, as in primrec; rules may be named
  4538 individually as well, resulting in a separate list of theorems for
  4539 each equation;
  4540 
  4541 * HOL/While is a new theory that provides a while-combinator. It
  4542 permits the definition of tail-recursive functions without the
  4543 provision of a termination measure. The latter is necessary once the
  4544 invariant proof rule for while is applied.
  4545 
  4546 * HOL: new (overloaded) notation for the set of elements below/above
  4547 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4548 
  4549 * HOL: theorems impI, allI, ballI bound as "strip";
  4550 
  4551 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4552 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4553 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4554 
  4555 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4556 
  4557 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4558 main HOL, but was unused);
  4559 
  4560 * HOL: fewer consts declared as global (e.g. have to refer to
  4561 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4562 
  4563 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4564 in case of overlap with user translations (e.g. judgements over
  4565 tuples); (note that the underlying logical represenation is still
  4566 bogus);
  4567 
  4568 
  4569 *** ZF ***
  4570 
  4571 * ZF: simplification automatically cancels common terms in arithmetic
  4572 expressions over nat and int;
  4573 
  4574 * ZF: new treatment of nat to minimize type-checking: all operators
  4575 coerce their operands to a natural number using the function natify,
  4576 making the algebraic laws unconditional;
  4577 
  4578 * ZF: as above, for int: operators coerce their operands to an integer
  4579 using the function intify;
  4580 
  4581 * ZF: the integer library now contains many of the usual laws for the
  4582 orderings, including $<=, and monotonicity laws for $+ and $*;
  4583 
  4584 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4585 simplification;
  4586 
  4587 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4588 to the simplifier and classical reasoner simultaneously;
  4589 
  4590 
  4591 *** General ***
  4592 
  4593 * Provers: blast_tac now handles actual object-logic rules as
  4594 assumptions; note that auto_tac uses blast_tac internally as well;
  4595 
  4596 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4597 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4598 
  4599 * Provers: delrules now handles destruct rules as well (no longer need
  4600 explicit make_elim);
  4601 
  4602 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4603   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4604 use instead the strong form,
  4605   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4606 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4607 from destruct-rules;
  4608 
  4609 * Provers: Simplifier.easy_setup provides a fast path to basic
  4610 Simplifier setup for new object-logics;
  4611 
  4612 * Pure: AST translation rules no longer require constant head on LHS;
  4613 
  4614 * Pure: improved name spaces: ambiguous output is qualified; support
  4615 for hiding of names;
  4616 
  4617 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4618 XSYMBOL_HOME; no longer need to do manual configuration in most
  4619 situations;
  4620 
  4621 * system: compression of ML heaps images may now be controlled via -c
  4622 option of isabelle and isatool usedir (currently only observed by
  4623 Poly/ML);
  4624 
  4625 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4626 useful for remote X11);
  4627 
  4628 * system: provide TAGS file for Isabelle sources;
  4629 
  4630 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4631 order;
  4632 
  4633 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4634 timing flag supersedes proof_timing and Toplevel.trace;
  4635 
  4636 * ML: new combinators |>> and |>>> for incremental transformations
  4637 with secondary results (e.g. certain theory extensions):
  4638 
  4639 * ML: PureThy.add_defs gets additional argument to indicate potential
  4640 overloading (usually false);
  4641 
  4642 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4643 results;
  4644 
  4645 
  4646 
  4647 New in Isabelle99 (October 1999)
  4648 --------------------------------
  4649 
  4650 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4651 
  4652 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4653 are no longer simplified.  (This allows the simplifier to unfold recursive
  4654 functional programs.)  To restore the old behaviour, declare
  4655 
  4656     Delcongs [if_weak_cong];
  4657 
  4658 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4659 complement;
  4660 
  4661 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4662 
  4663 * HOL/datatype: mutual_induct_tac no longer exists --
  4664   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4665 
  4666 * HOL/typedef: fixed type inference for representing set; type
  4667 arguments now have to occur explicitly on the rhs as type constraints;
  4668 
  4669 * ZF: The con_defs part of an inductive definition may no longer refer
  4670 to constants declared in the same theory;
  4671 
  4672 * HOL, ZF: the function mk_cases, generated by the inductive
  4673 definition package, has lost an argument.  To simplify its result, it
  4674 uses the default simpset instead of a supplied list of theorems.
  4675 
  4676 * HOL/List: the constructors of type list are now Nil and Cons;
  4677 
  4678 * Simplifier: the type of the infix ML functions
  4679         setSSolver addSSolver setSolver addSolver
  4680 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4681 for packaging solvers. A solver is created via
  4682         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4683 where the string argument is only a comment.
  4684 
  4685 
  4686 *** Proof tools ***
  4687 
  4688 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4689 decision procedure for linear arithmetic. Currently it is used for
  4690 types `nat', `int', and `real' in HOL (see below); it can, should and
  4691 will be instantiated for other types and logics as well.
  4692 
  4693 * The simplifier now accepts rewrite rules with flexible heads, eg
  4694      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4695   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4696   matching.
  4697 
  4698 
  4699 *** General ***
  4700 
  4701 * New Isabelle/Isar subsystem provides an alternative to traditional
  4702 tactical theorem proving; together with the ProofGeneral/isar user
  4703 interface it offers an interactive environment for developing human
  4704 readable proof documents (Isar == Intelligible semi-automated
  4705 reasoning); for further information see isatool doc isar-ref,
  4706 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4707 
  4708 * improved and simplified presentation of theories: better HTML markup
  4709 (including colors), graph views in several sizes; isatool usedir now
  4710 provides a proper interface for user theories (via -P option); actual
  4711 document preparation based on (PDF)LaTeX is available as well (for
  4712 new-style theories only); see isatool doc system for more information;
  4713 
  4714 * native support for Proof General, both for classic Isabelle and
  4715 Isabelle/Isar;
  4716 
  4717 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4718 using the graph browser tool;
  4719 
  4720 * Isabelle manuals now also available as PDF;
  4721 
  4722 * theory loader rewritten from scratch (may not be fully
  4723 bug-compatible); old loadpath variable has been replaced by show_path,
  4724 add_path, del_path, reset_path functions; new operations such as
  4725 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4726 isatool doc ref);
  4727 
  4728 * improved isatool install: option -k creates KDE application icon,
  4729 option -p DIR installs standalone binaries;
  4730 
  4731 * added ML_PLATFORM setting (useful for cross-platform installations);
  4732 more robust handling of platform specific ML images for SML/NJ;
  4733 
  4734 * the settings environment is now statically scoped, i.e. it is never
  4735 created again in sub-processes invoked from isabelle, isatool, or
  4736 Isabelle;
  4737 
  4738 * path element specification '~~' refers to '$ISABELLE_HOME';
  4739 
  4740 * in locales, the "assumes" and "defines" parts may be omitted if
  4741 empty;
  4742 
  4743 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4744 long arrows);
  4745 
  4746 * new print_mode "HTML";
  4747 
  4748 * new flag show_tags controls display of tags of theorems (which are
  4749 basically just comments that may be attached by some tools);
  4750 
  4751 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4752 mode and goal output format:
  4753 
  4754 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4755 244c244
  4756 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4757 ---
  4758 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4759 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4760 181c181
  4761 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4762 ---
  4763 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4764 
  4765 * function bind_thms stores lists of theorems (cf. bind_thm);
  4766 
  4767 * new shorthand tactics ftac, eatac, datac, fatac;
  4768 
  4769 * qed (and friends) now accept "" as result name; in that case the
  4770 theorem is not stored, but proper checks and presentation of the
  4771 result still apply;
  4772 
  4773 * theorem database now also indexes constants "Trueprop", "all",
  4774 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4775 
  4776 
  4777 *** HOL ***
  4778 
  4779 ** HOL arithmetic **
  4780 
  4781 * There are now decision procedures for linear arithmetic over nat and
  4782 int:
  4783 
  4784 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4785 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4786 are treated as atomic; subformulae not involving type `nat' or `int'
  4787 are ignored; quantified subformulae are ignored unless they are
  4788 positive universal or negative existential. The tactic has to be
  4789 invoked by hand and can be a little bit slow. In particular, the
  4790 running time is exponential in the number of occurrences of `min' and
  4791 `max', and `-' on `nat'.
  4792 
  4793 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4794 (negated) (in)equalities among the premises and the conclusion into
  4795 account (i.e. no compound formulae) and does not know about `min' and
  4796 `max', and `-' on `nat'. It is fast and is used automatically by the
  4797 simplifier.
  4798 
  4799 NB: At the moment, these decision procedures do not cope with mixed
  4800 nat/int formulae where the two parts interact, such as `m < n ==>
  4801 int(m) < int(n)'.
  4802 
  4803 * HOL/Numeral provides a generic theory of numerals (encoded
  4804 efficiently as bit strings); setup for types nat/int/real is in place;
  4805 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4806 int, existing theories and proof scripts may require a few additional
  4807 type constraints;
  4808 
  4809 * integer division and remainder can now be performed on constant
  4810 arguments;
  4811 
  4812 * many properties of integer multiplication, division and remainder
  4813 are now available;
  4814 
  4815 * An interface to the Stanford Validity Checker (SVC) is available through the
  4816 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4817 are proved automatically.  SVC must be installed separately, and its results
  4818 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4819 invocation of the underlying oracle).  For SVC see
  4820   http://verify.stanford.edu/SVC
  4821 
  4822 * IsaMakefile: the HOL-Real target now builds an actual image;
  4823 
  4824 
  4825 ** HOL misc **
  4826 
  4827 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4828 (in Isabelle/Isar) -- by Gertrud Bauer;
  4829 
  4830 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4831 analysis for assembly languages with subtypes;
  4832 
  4833 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4834 -- avoids syntactic ambiguities and treats state, transition, and
  4835 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4836 changed syntax and (many) tactics;
  4837 
  4838 * HOL/inductive: Now also handles more general introduction rules such
  4839   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4840   theorems are now maintained within the theory (maintained via the
  4841   "mono" attribute);
  4842 
  4843 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4844   (using function types) such as
  4845 
  4846   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4847 
  4848 * HOL/record: record_simproc (part of the default simpset) takes care
  4849 of selectors applied to updated records; record_split_tac is no longer
  4850 part of the default claset; update_defs may now be removed from the
  4851 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4852 
  4853   claset_ref () := claset() addSWrapper record_split_wrapper;
  4854   Delsimprocs [record_simproc]
  4855 
  4856 * HOL/typedef: fixed type inference for representing set; type
  4857 arguments now have to occur explicitly on the rhs as type constraints;
  4858 
  4859 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4860 names rather than an ML expression;
  4861 
  4862 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4863 supplied later.  Program schemes can be defined, such as
  4864     "While B C s = (if B s then While B C (C s) else s)"
  4865 where the well-founded relation can be chosen after B and C have been given.
  4866 
  4867 * HOL/List: the constructors of type list are now Nil and Cons;
  4868 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4869 course, ML tools referring to List.list.op # etc. have to be adapted;
  4870 
  4871 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4872 disabled by default; run isabelle with option -m HOL to get back to
  4873 the original Gordon/HOL-style output;
  4874 
  4875 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4876 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4877 
  4878 * HOL basic syntax simplified (more orthogonal): all variants of
  4879 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4880 Eps operator is provided as well: "SOME x. P[x]";
  4881 
  4882 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4883 
  4884 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4885 thus available for user theories;
  4886 
  4887 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4888 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4889 time;
  4890 
  4891 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4892 several times and then mp;
  4893 
  4894 
  4895 *** LK ***
  4896 
  4897 * the notation <<...>> is now available as a notation for sequences of
  4898 formulas;
  4899 
  4900 * the simplifier is now installed
  4901 
  4902 * the axiom system has been generalized (thanks to Soren Heilmann)
  4903 
  4904 * the classical reasoner now has a default rule database
  4905 
  4906 
  4907 *** ZF ***
  4908 
  4909 * new primrec section allows primitive recursive functions to be given
  4910 directly (as in HOL) over datatypes and the natural numbers;
  4911 
  4912 * new tactics induct_tac and exhaust_tac for induction (or case
  4913 analysis) over datatypes and the natural numbers;
  4914 
  4915 * the datatype declaration of type T now defines the recursor T_rec;
  4916 
  4917 * simplification automatically does freeness reasoning for datatype
  4918 constructors;
  4919 
  4920 * automatic type-inference, with AddTCs command to insert new
  4921 type-checking rules;
  4922 
  4923 * datatype introduction rules are now added as Safe Introduction rules
  4924 to the claset;
  4925 
  4926 * the syntax "if P then x else y" is now available in addition to
  4927 if(P,x,y);
  4928 
  4929 
  4930 *** Internal programming interfaces ***
  4931 
  4932 * tuned simplifier trace output; new flag debug_simp;
  4933 
  4934 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4935 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4936 
  4937 * AxClass.axclass_tac lost the theory argument;
  4938 
  4939 * tuned current_goals_markers semantics: begin / end goal avoids
  4940 printing empty lines;
  4941 
  4942 * removed prs and prs_fn hook, which was broken because it did not
  4943 include \n in its semantics, forcing writeln to add one
  4944 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4945 string -> unit if you really want to output text without newline;
  4946 
  4947 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4948 plain output, interface builders may have to enable 'isabelle_font'
  4949 mode to get Isabelle font glyphs as before;
  4950 
  4951 * refined token_translation interface; INCOMPATIBILITY: output length
  4952 now of type real instead of int;
  4953 
  4954 * theory loader actions may be traced via new ThyInfo.add_hook
  4955 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4956 your own database of information attached to *whole* theories -- as
  4957 opposed to intra-theory data slots offered via TheoryDataFun;
  4958 
  4959 * proper handling of dangling sort hypotheses (at last!);
  4960 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4961 extra sort hypotheses that can be witnessed from the type signature;
  4962 the force_strip_shyps flag is gone, any remaining shyps are simply
  4963 left in the theorem (with a warning issued by strip_shyps_warning);
  4964 
  4965 
  4966 
  4967 New in Isabelle98-1 (October 1998)
  4968 ----------------------------------
  4969 
  4970 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4971 
  4972 * several changes of automated proof tools;
  4973 
  4974 * HOL: major changes to the inductive and datatype packages, including
  4975 some minor incompatibilities of theory syntax;
  4976 
  4977 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4978 called `inj_on';
  4979 
  4980 * HOL: removed duplicate thms in Arith:
  4981   less_imp_add_less  should be replaced by  trans_less_add1
  4982   le_imp_add_le      should be replaced by  trans_le_add1
  4983 
  4984 * HOL: unary minus is now overloaded (new type constraints may be
  4985 required);
  4986 
  4987 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4988 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4989 now taken as an integer constant.
  4990 
  4991 * Pure: ML function 'theory_of' renamed to 'theory';
  4992 
  4993 
  4994 *** Proof tools ***
  4995 
  4996 * Simplifier:
  4997   1. Asm_full_simp_tac is now more aggressive.
  4998      1. It will sometimes reorient premises if that increases their power to
  4999         simplify.
  5000      2. It does no longer proceed strictly from left to right but may also
  5001         rotate premises to achieve further simplification.
  5002      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5003      old Asm_full_simp_tac in that it does not rotate premises.
  5004   2. The simplifier now knows a little bit about nat-arithmetic.
  5005 
  5006 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5007 allows for selected deletion of wrappers, by introduction of names for
  5008 wrapper functionals.  This implies that addbefore, addSbefore,
  5009 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5010 and that adding two tactics with the same name overwrites the first
  5011 one (emitting a warning).
  5012   type wrapper = (int -> tactic) -> (int -> tactic)
  5013   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5014   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5015   delWrapper, delSWrapper: claset *  string            -> claset
  5016   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5017 
  5018 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5019 semantics; addbefore now affects only the unsafe part of step_tac
  5020 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5021 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5022 by Force_tac;
  5023 
  5024 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5025 compWrapper; added safe wrapper (and access functions for it);
  5026 
  5027 * HOL/split_all_tac is now much faster and fails if there is nothing
  5028 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5029 and the names of the automatically generated variables have changed.
  5030 split_all_tac has moved within claset() from unsafe wrappers to safe
  5031 wrappers, which means that !!-bound variables are split much more
  5032 aggressively, and safe_tac and clarify_tac now split such variables.
  5033 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5034 Note: the same holds for record_split_tac, which does the job of
  5035 split_all_tac for record fields.
  5036 
  5037 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5038 permanently to the default simpset using Addsplits just like
  5039 Addsimps. They can be removed via Delsplits just like
  5040 Delsimps. Lower-case versions are also available.
  5041 
  5042 * HOL/Simplifier: The rule split_if is now part of the default
  5043 simpset. This means that the simplifier will eliminate all occurrences
  5044 of if-then-else in the conclusion of a goal. To prevent this, you can
  5045 either remove split_if completely from the default simpset by
  5046 `Delsplits [split_if]' or remove it in a specific call of the
  5047 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5048 other case splitting rules to/from the default simpset: every datatype
  5049 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5050 t is the name of the datatype).
  5051 
  5052 * Classical reasoner / Simplifier combination: new force_tac (and
  5053 derivatives Force_tac, force) combines rewriting and classical
  5054 reasoning (and whatever other tools) similarly to auto_tac, but is
  5055 aimed to solve the given subgoal completely.
  5056 
  5057 
  5058 *** General ***
  5059 
  5060 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5061 and `goalw': the theory is no longer needed as an explicit argument -
  5062 the current theory context is used; assumptions are no longer returned
  5063 at the ML-level unless one of them starts with ==> or !!; it is
  5064 recommended to convert to these new commands using isatool fixgoal
  5065 (backup your sources first!);
  5066 
  5067 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5068 the current theory context, and 'theory' to lookup stored theories;
  5069 
  5070 * new theory section 'locale' for declaring constants, assumptions and
  5071 definitions that have local scope;
  5072 
  5073 * new theory section 'nonterminals' for purely syntactic types;
  5074 
  5075 * new theory section 'setup' for generic ML setup functions
  5076 (e.g. package initialization);
  5077 
  5078 * the distribution now includes Isabelle icons: see
  5079 lib/logo/isabelle-{small,tiny}.xpm;
  5080 
  5081 * isatool install - install binaries with absolute references to
  5082 ISABELLE_HOME/bin;
  5083 
  5084 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5085 
  5086 * print mode 'emacs' reserved for Isamode;
  5087 
  5088 * support multiple print (ast) translations per constant name;
  5089 
  5090 * theorems involving oracles are now printed with a suffixed [!];
  5091 
  5092 
  5093 *** HOL ***
  5094 
  5095 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5096 
  5097 * HOL/inductive package reorganized and improved: now supports mutual
  5098 definitions such as
  5099 
  5100   inductive EVEN ODD
  5101     intrs
  5102       null "0 : EVEN"
  5103       oddI "n : EVEN ==> Suc n : ODD"
  5104       evenI "n : ODD ==> Suc n : EVEN"
  5105 
  5106 new theorem list "elims" contains an elimination rule for each of the
  5107 recursive sets; inductive definitions now handle disjunctive premises
  5108 correctly (also ZF);
  5109 
  5110 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5111 "mutual_induct" no longer exists - the induction rule is always
  5112 contained in "induct";
  5113 
  5114 
  5115 * HOL/datatype package re-implemented and greatly improved: now
  5116 supports mutually recursive datatypes such as
  5117 
  5118   datatype
  5119     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5120             | SUM ('a aexp) ('a aexp)
  5121             | DIFF ('a aexp) ('a aexp)
  5122             | NUM 'a
  5123   and
  5124     'a bexp = LESS ('a aexp) ('a aexp)
  5125             | AND ('a bexp) ('a bexp)
  5126             | OR ('a bexp) ('a bexp)
  5127 
  5128 as well as indirectly recursive datatypes such as
  5129 
  5130   datatype
  5131     ('a, 'b) term = Var 'a
  5132                   | App 'b ((('a, 'b) term) list)
  5133 
  5134 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5135 induction on mutually / indirectly recursive datatypes.
  5136 
  5137 Primrec equations are now stored in theory and can be accessed via
  5138 <function_name>.simps.
  5139 
  5140 INCOMPATIBILITIES:
  5141 
  5142   - Theories using datatypes must now have theory Datatype as an
  5143     ancestor.
  5144   - The specific <typename>.induct_tac no longer exists - use the
  5145     generic induct_tac instead.
  5146   - natE has been renamed to nat.exhaust - use exhaust_tac
  5147     instead of res_inst_tac ... natE. Note that the variable
  5148     names in nat.exhaust differ from the names in natE, this
  5149     may cause some "fragile" proofs to fail.
  5150   - The theorems split_<typename>_case and split_<typename>_case_asm
  5151     have been renamed to <typename>.split and <typename>.split_asm.
  5152   - Since default sorts of type variables are now handled correctly,
  5153     some datatype definitions may have to be annotated with explicit
  5154     sort constraints.
  5155   - Primrec definitions no longer require function name and type
  5156     of recursive argument.
  5157 
  5158 Consider using isatool fixdatatype to adapt your theories and proof
  5159 scripts to the new package (backup your sources first!).
  5160 
  5161 
  5162 * HOL/record package: considerably improved implementation; now
  5163 includes concrete syntax for record types, terms, updates; theorems
  5164 for surjective pairing and splitting !!-bound record variables; proof
  5165 support is as follows:
  5166 
  5167   1) standard conversions (selectors or updates applied to record
  5168 constructor terms) are part of the standard simpset;
  5169 
  5170   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5171 made part of standard simpset and claset via addIffs;
  5172 
  5173   3) a tactic for record field splitting (record_split_tac) is part of
  5174 the standard claset (addSWrapper);
  5175 
  5176 To get a better idea about these rules you may retrieve them via
  5177 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5178 the name of your record type.
  5179 
  5180 The split tactic 3) conceptually simplifies by the following rule:
  5181 
  5182   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5183 
  5184 Thus any record variable that is bound by meta-all will automatically
  5185 blow up into some record constructor term, consequently the
  5186 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5187 solve record problems automatically.
  5188 
  5189 
  5190 * reorganized the main HOL image: HOL/Integ and String loaded by
  5191 default; theory Main includes everything;
  5192 
  5193 * automatic simplification of integer sums and comparisons, using cancellation;
  5194 
  5195 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5196 
  5197 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5198 
  5199 * many new identities for unions, intersections, set difference, etc.;
  5200 
  5201 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5202 called split_if, split_split, split_sum_case and split_nat_case (to go
  5203 with add/delsplits);
  5204 
  5205 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5206 (?x::unit) = (); this is made part of the default simpset, which COULD
  5207 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5208 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5209 unit_abs_eta_conv is added in order to counter the effect of
  5210 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5211 %u.f();
  5212 
  5213 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5214 makes more sense);
  5215 
  5216 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5217   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5218   disjointness reasoning but breaking a few old proofs.
  5219 
  5220 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5221 to 'converse' from 'inverse' (for compatibility with ZF and some
  5222 literature);
  5223 
  5224 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5225 the well-founded relation;
  5226 
  5227 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5228     Compl A.  The "Compl" syntax remains available as input syntax for this
  5229     release ONLY.
  5230 
  5231 * HOL/Update: new theory of function updates:
  5232     f(a:=b) == %x. if x=a then b else f x
  5233 may also be iterated as in f(a:=b,c:=d,...);
  5234 
  5235 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5236 
  5237 * HOL/List:
  5238   - new function list_update written xs[i:=v] that updates the i-th
  5239     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5240   - new function `upt' written [i..j(] which generates the list
  5241     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5242     bound write [i..j], which is a shorthand for [i..j+1(].
  5243   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5244 
  5245 * HOL/Arith:
  5246   - removed 'pred' (predecessor) function;
  5247   - generalized some theorems about n-1;
  5248   - many new laws about "div" and "mod";
  5249   - new laws about greatest common divisors (see theory ex/Primes);
  5250 
  5251 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5252 instead of "inverse";
  5253 
  5254 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5255   of the multiset ordering;
  5256 
  5257 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5258   (not included by default);
  5259 
  5260 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5261 
  5262 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5263   programs, i.e. different program variables may have different types.
  5264 
  5265 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5266   [previously, this check worked only if the rewrite rule was unconditional]
  5267   Now rew can involve either definitions or equalities (either == or =).
  5268 
  5269 
  5270 *** ZF ***
  5271 
  5272 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5273   only the theorems proved on ZF.ML;
  5274 
  5275 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5276   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5277   disjointness reasoning but breaking a few old proofs.
  5278 
  5279 * ZF/Update: new theory of function updates
  5280     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5281   may also be iterated as in f(a:=b,c:=d,...);
  5282 
  5283 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5284 
  5285 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5286   [previously, this check worked only if the rewrite rule was unconditional]
  5287   Now rew can involve either definitions or equalities (either == or =).
  5288 
  5289 * case_tac provided for compatibility with HOL
  5290     (like the old excluded_middle_tac, but with subgoals swapped)
  5291 
  5292 
  5293 *** Internal programming interfaces ***
  5294 
  5295 * Pure: several new basic modules made available for general use, see
  5296 also src/Pure/README;
  5297 
  5298 * improved the theory data mechanism to support encapsulation (data
  5299 kind name replaced by private Object.kind, acting as authorization
  5300 key); new type-safe user interface via functor TheoryDataFun; generic
  5301 print_data function becomes basically useless;
  5302 
  5303 * removed global_names compatibility flag -- all theory declarations
  5304 are qualified by default;
  5305 
  5306 * module Pure/Syntax now offers quote / antiquote translation
  5307 functions (useful for Hoare logic etc. with implicit dependencies);
  5308 see HOL/ex/Antiquote for an example use;
  5309 
  5310 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5311 cterm -> thm;
  5312 
  5313 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5314 subgoal;
  5315 
  5316 * Display.print_goals function moved to Locale.print_goals;
  5317 
  5318 * standard print function for goals supports current_goals_markers
  5319 variable for marking begin of proof, end of proof, start of goal; the
  5320 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5321 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5322 for example;
  5323 
  5324 
  5325 
  5326 New in Isabelle98 (January 1998)
  5327 --------------------------------
  5328 
  5329 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5330 
  5331 * changed lexical syntax of terms / types: dots made part of long
  5332 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5333 
  5334 * simpset (and claset) reference variable replaced by functions
  5335 simpset / simpset_ref;
  5336 
  5337 * no longer supports theory aliases (via merge) and non-trivial
  5338 implicit merge of thms' signatures;
  5339 
  5340 * most internal names of constants changed due to qualified names;
  5341 
  5342 * changed Pure/Sequence interface (see Pure/seq.ML);
  5343 
  5344 
  5345 *** General Changes ***
  5346 
  5347 * hierachically structured name spaces (for consts, types, axms, thms
  5348 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5349 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5350 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5351 long_names for fully qualified output names; NOTE: ML programs
  5352 (special tactics, packages etc.) referring to internal names may have
  5353 to be adapted to cope with fully qualified names; in case of severe
  5354 backward campatibility problems try setting 'global_names' at compile
  5355 time to have enrything declared within a flat name space; one may also
  5356 fine tune name declarations in theories via the 'global' and 'local'
  5357 section;
  5358 
  5359 * reimplemented the implicit simpset and claset using the new anytype
  5360 data filed in signatures; references simpset:simpset ref etc. are
  5361 replaced by functions simpset:unit->simpset and
  5362 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5363 to patch your ML files accordingly;
  5364 
  5365 * HTML output now includes theory graph data for display with Java
  5366 applet or isatool browser; data generated automatically via isatool
  5367 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5368 
  5369 * defs may now be conditional; improved rewrite_goals_tac to handle
  5370 conditional equations;
  5371 
  5372 * defs now admits additional type arguments, using TYPE('a) syntax;
  5373 
  5374 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5375 creates a new theory node; implicit merge of thms' signatures is
  5376 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5377 transfer:theory->thm->thm in (rare) cases;
  5378 
  5379 * improved handling of draft signatures / theories; draft thms (and
  5380 ctyps, cterms) are automatically promoted to real ones;
  5381 
  5382 * slightly changed interfaces for oracles: admit many per theory, named
  5383 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5384 
  5385 * print_goals: optional output of const types (set show_consts and
  5386 show_types);
  5387 
  5388 * improved output of warnings (###) and errors (***);
  5389 
  5390 * subgoal_tac displays a warning if the new subgoal has type variables;
  5391 
  5392 * removed old README and Makefiles;
  5393 
  5394 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5395 
  5396 * removed obsolete init_pps and init_database;
  5397 
  5398 * deleted the obsolete tactical STATE, which was declared by
  5399     fun STATE tacfun st = tacfun st st;
  5400 
  5401 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5402 (which abbreviates $HOME);
  5403 
  5404 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5405 use isatool fixseq to adapt your ML programs (this works for fully
  5406 qualified references to the Sequence structure only!);
  5407 
  5408 * use_thy no longer requires writable current directory; it always
  5409 reloads .ML *and* .thy file, if either one is out of date;
  5410 
  5411 
  5412 *** Classical Reasoner ***
  5413 
  5414 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5415 tactics that use classical reasoning to simplify a subgoal without
  5416 splitting it into several subgoals;
  5417 
  5418 * Safe_tac: like safe_tac but uses the default claset;
  5419 
  5420 
  5421 *** Simplifier ***
  5422 
  5423 * added simplification meta rules:
  5424     (asm_)(full_)simplify: simpset -> thm -> thm;
  5425 
  5426 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5427 logics (again);
  5428 
  5429 * added prems argument to simplification procedures;
  5430 
  5431 * HOL, FOL, ZF: added infix function `addsplits':
  5432   instead of `<simpset> setloop (split_tac <thms>)'
  5433   you can simply write `<simpset> addsplits <thms>'
  5434 
  5435 
  5436 *** Syntax ***
  5437 
  5438 * TYPE('a) syntax for type reflection terms;
  5439 
  5440 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5441 
  5442 * pretty printer: changed order of mixfix annotation preference (again!);
  5443 
  5444 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5445 
  5446 
  5447 *** HOL ***
  5448 
  5449 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5450   with `addloop' of the simplifier to faciliate case splitting in premises.
  5451 
  5452 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5453 
  5454 * HOL/Auth: new protocol proofs including some for the Internet
  5455   protocol TLS;
  5456 
  5457 * HOL/Map: new theory of `maps' a la VDM;
  5458 
  5459 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5460 cancelling out common nat summands from =, <, <= (in)equalities, or
  5461 differences; simplification procedures nat_cancel_factor for
  5462 cancelling common factor from =, <, <= (in)equalities over natural
  5463 sums; nat_cancel contains both kinds of procedures, it is installed by
  5464 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5465 
  5466 * HOL/simplifier: terms of the form
  5467   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5468   are rewritten to
  5469   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5470   and those of the form
  5471   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5472   are rewritten to
  5473   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5474 
  5475 * HOL/datatype
  5476   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5477 
  5478   P(t_case f1 ... fn x) =
  5479      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5480         ...
  5481        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5482      )
  5483 
  5484   and a theorem `split_t_case_asm' of the form
  5485 
  5486   P(t_case f1 ... fn x) =
  5487     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5488         ...
  5489        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5490      )
  5491   which can be added to a simpset via `addsplits'. The existing theorems
  5492   expand_list_case and expand_option_case have been renamed to
  5493   split_list_case and split_option_case.
  5494 
  5495 * HOL/Arithmetic:
  5496   - `pred n' is automatically converted to `n-1'.
  5497     Users are strongly encouraged not to use `pred' any longer,
  5498     because it will disappear altogether at some point.
  5499   - Users are strongly encouraged to write "0 < n" rather than
  5500     "n ~= 0". Theorems and proof tools have been modified towards this
  5501     `standard'.
  5502 
  5503 * HOL/Lists:
  5504   the function "set_of_list" has been renamed "set" (and its theorems too);
  5505   the function "nth" now takes its arguments in the reverse order and
  5506   has acquired the infix notation "!" as in "xs!n".
  5507 
  5508 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5509 
  5510 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5511   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5512 
  5513 * HOL/record: extensible records with schematic structural subtyping
  5514 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5515 still lacks various theorems and concrete record syntax;
  5516 
  5517 
  5518 *** HOLCF ***
  5519 
  5520 * removed "axioms" and "generated by" sections;
  5521 
  5522 * replaced "ops" section by extended "consts" section, which is capable of
  5523   handling the continuous function space "->" directly;
  5524 
  5525 * domain package:
  5526   . proves theorems immediately and stores them in the theory,
  5527   . creates hierachical name space,
  5528   . now uses normal mixfix annotations (instead of cinfix...),
  5529   . minor changes to some names and values (for consistency),
  5530   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5531   . separator between mutual domain defs: changed "," to "and",
  5532   . improved handling of sort constraints;  now they have to
  5533     appear on the left-hand side of the equations only;
  5534 
  5535 * fixed LAM <x,y,zs>.b syntax;
  5536 
  5537 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5538 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5539 
  5540 
  5541 *** FOL and ZF ***
  5542 
  5543 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5544   with `addloop' of the simplifier to faciliate case splitting in premises.
  5545 
  5546 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5547 in HOL, they strip ALL and --> from proved theorems;
  5548 
  5549 
  5550 
  5551 New in Isabelle94-8 (May 1997)
  5552 ------------------------------
  5553 
  5554 *** General Changes ***
  5555 
  5556 * new utilities to build / run / maintain Isabelle etc. (in parts
  5557 still somewhat experimental); old Makefiles etc. still functional;
  5558 
  5559 * new 'Isabelle System Manual';
  5560 
  5561 * INSTALL text, together with ./configure and ./build scripts;
  5562 
  5563 * reimplemented type inference for greater efficiency, better error
  5564 messages and clean internal interface;
  5565 
  5566 * prlim command for dealing with lots of subgoals (an easier way of
  5567 setting goals_limit);
  5568 
  5569 
  5570 *** Syntax ***
  5571 
  5572 * supports alternative (named) syntax tables (parser and pretty
  5573 printer); internal interface is provided by add_modesyntax(_i);
  5574 
  5575 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5576 be used in conjunction with the Isabelle symbol font; uses the
  5577 "symbols" syntax table;
  5578 
  5579 * added token_translation interface (may translate name tokens in
  5580 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5581 the current print_mode); IMPORTANT: user print translation functions
  5582 are responsible for marking newly introduced bounds
  5583 (Syntax.mark_boundT);
  5584 
  5585 * token translations for modes "xterm" and "xterm_color" that display
  5586 names in bold, underline etc. or colors (which requires a color
  5587 version of xterm);
  5588 
  5589 * infixes may now be declared with names independent of their syntax;
  5590 
  5591 * added typed_print_translation (like print_translation, but may
  5592 access type of constant);
  5593 
  5594 
  5595 *** Classical Reasoner ***
  5596 
  5597 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5598 some limitations.  Blast_tac...
  5599   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5600   + ignores elimination rules that don't have the correct format
  5601         (the conclusion MUST be a formula variable)
  5602   + ignores types, which can make HOL proofs fail
  5603   + rules must not require higher-order unification, e.g. apply_type in ZF
  5604     [message "Function Var's argument not a bound variable" relates to this]
  5605   + its proof strategy is more general but can actually be slower
  5606 
  5607 * substitution with equality assumptions no longer permutes other
  5608 assumptions;
  5609 
  5610 * minor changes in semantics of addafter (now called addaltern); renamed
  5611 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5612 (and access functions for it);
  5613 
  5614 * improved combination of classical reasoner and simplifier:
  5615   + functions for handling clasimpsets
  5616   + improvement of addss: now the simplifier is called _after_ the
  5617     safe steps.
  5618   + safe variant of addss called addSss: uses safe simplifications
  5619     _during_ the safe steps. It is more complete as it allows multiple
  5620     instantiations of unknowns (e.g. with slow_tac).
  5621 
  5622 *** Simplifier ***
  5623 
  5624 * added interface for simplification procedures (functions that
  5625 produce *proven* rewrite rules on the fly, depending on current
  5626 redex);
  5627 
  5628 * ordering on terms as parameter (used for ordered rewriting);
  5629 
  5630 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5631 
  5632 * the solver is now split into a safe and an unsafe part.
  5633 This should be invisible for the normal user, except that the
  5634 functions setsolver and addsolver have been renamed to setSolver and
  5635 addSolver; added safe_asm_full_simp_tac;
  5636 
  5637 
  5638 *** HOL ***
  5639 
  5640 * a generic induction tactic `induct_tac' which works for all datatypes and
  5641 also for type `nat';
  5642 
  5643 * a generic case distinction tactic `exhaust_tac' which works for all
  5644 datatypes and also for type `nat';
  5645 
  5646 * each datatype comes with a function `size';
  5647 
  5648 * patterns in case expressions allow tuple patterns as arguments to
  5649 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5650 
  5651 * primrec now also works with type nat;
  5652 
  5653 * recdef: a new declaration form, allows general recursive functions to be
  5654 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5655 
  5656 * the constant for negation has been renamed from "not" to "Not" to
  5657 harmonize with FOL, ZF, LK, etc.;
  5658 
  5659 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5660 infinite lists;
  5661 
  5662 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5663 
  5664 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5665 problems in commutative rings, using axiomatic type classes for + and *;
  5666 
  5667 * more examples in HOL/MiniML and HOL/Auth;
  5668 
  5669 * more default rewrite rules for quantifiers, union/intersection;
  5670 
  5671 * a new constant `arbitrary == @x.False';
  5672 
  5673 * HOLCF/IOA replaces old HOL/IOA;
  5674 
  5675 * HOLCF changes: derived all rules and arities
  5676   + axiomatic type classes instead of classes
  5677   + typedef instead of faking type definitions
  5678   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5679   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5680   + eliminated the types void, one, tr
  5681   + use unit lift and bool lift (with translations) instead of one and tr
  5682   + eliminated blift from Lift3.thy (use Def instead of blift)
  5683   all eliminated rules are derived as theorems --> no visible changes ;
  5684 
  5685 
  5686 *** ZF ***
  5687 
  5688 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5689 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5690 as ZF_cs addSIs [equalityI];
  5691 
  5692 
  5693 
  5694 New in Isabelle94-7 (November 96)
  5695 ---------------------------------
  5696 
  5697 * allowing negative levels (as offsets) in prlev and choplev;
  5698 
  5699 * super-linear speedup for large simplifications;
  5700 
  5701 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5702 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5703 FAIL); can suppress it using the command Delsimps (ex_simps @
  5704 all_simps); De Morgan laws are also now included, by default;
  5705 
  5706 * improved printing of ==>  :  ~:
  5707 
  5708 * new object-logic "Sequents" adds linear logic, while replacing LK
  5709 and Modal (thanks to Sara Kalvala);
  5710 
  5711 * HOL/Auth: correctness proofs for authentication protocols;
  5712 
  5713 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5714 examples on HOL/Auth);
  5715 
  5716 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5717 the rewriter and classical reasoner simultaneously;
  5718 
  5719 * function uresult no longer returns theorems in "standard" format;
  5720 regain previous version by: val uresult = standard o uresult;
  5721 
  5722 
  5723 
  5724 New in Isabelle94-6
  5725 -------------------
  5726 
  5727 * oracles -- these establish an interface between Isabelle and trusted
  5728 external reasoners, which may deliver results as theorems;
  5729 
  5730 * proof objects (in particular record all uses of oracles);
  5731 
  5732 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5733 
  5734 * "constdefs" section in theory files;
  5735 
  5736 * "primrec" section (HOL) no longer requires names;
  5737 
  5738 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5739 
  5740 
  5741 
  5742 New in Isabelle94-5
  5743 -------------------
  5744 
  5745 * reduced space requirements;
  5746 
  5747 * automatic HTML generation from theories;
  5748 
  5749 * theory files no longer require "..." (quotes) around most types;
  5750 
  5751 * new examples, including two proofs of the Church-Rosser theorem;
  5752 
  5753 * non-curried (1994) version of HOL is no longer distributed;
  5754 
  5755 
  5756 
  5757 New in Isabelle94-4
  5758 -------------------
  5759 
  5760 * greatly reduced space requirements;
  5761 
  5762 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5763 
  5764 * searchable theorem database (see the section "Retrieving theorems" on
  5765 page 8 of the Reference Manual);
  5766 
  5767 * new examples, including Grabczewski's monumental case study of the
  5768 Axiom of Choice;
  5769 
  5770 * The previous version of HOL renamed to Old_HOL;
  5771 
  5772 * The new version of HOL (previously called CHOL) uses a curried syntax
  5773 for functions.  Application looks like f a b instead of f(a,b);
  5774 
  5775 * Mutually recursive inductive definitions finally work in HOL;
  5776 
  5777 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5778 translates to the operator "split";
  5779 
  5780 
  5781 
  5782 New in Isabelle94-3
  5783 -------------------
  5784 
  5785 * new infix operator, addss, allowing the classical reasoner to
  5786 perform simplification at each step of its search.  Example:
  5787         fast_tac (cs addss ss)
  5788 
  5789 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5790 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5791 look like (a,b) instead of <a,b>;
  5792 
  5793 * PLEASE NOTE: CHOL will eventually replace HOL!
  5794 
  5795 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5796 It translates to the operator "split".  A new theory of integers is available;
  5797 
  5798 * In ZF, integer numerals now denote two's-complement binary integers.
  5799 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5800 
  5801 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5802 of the Axiom of Choice;
  5803 
  5804 
  5805 
  5806 New in Isabelle94-2
  5807 -------------------
  5808 
  5809 * Significantly faster resolution;
  5810 
  5811 * the different sections in a .thy file can now be mixed and repeated
  5812 freely;
  5813 
  5814 * Database of theorems for FOL, HOL and ZF.  New
  5815 commands including qed, qed_goal and bind_thm store theorems in the database.
  5816 
  5817 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5818 a given theory (thms_of), or find out what theory a theorem was proved in
  5819 (theory_of_thm);
  5820 
  5821 * Bugs fixed in the inductive definition and datatype packages;
  5822 
  5823 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5824 and HOL_dup_cs obsolete;
  5825 
  5826 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5827 have been removed;
  5828 
  5829 * Simpler definition of function space in ZF;
  5830 
  5831 * new results about cardinal and ordinal arithmetic in ZF;
  5832 
  5833 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5834 types;
  5835 
  5836 :mode=text:wrap=hard:maxLineLen=72:
  5837 
  5838 
  5839 $Id$