NEWS
author ballarin
Tue Oct 28 17:53:46 2008 +0100 (2008-10-28)
changeset 28707 548703affff5
parent 28700 fb92b1d1b285
child 28710 e2064974c114
permissions -rw-r--r--
Revoked workaround (incompatible with HOL/ex/LocaleTest2.thy).
     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 * New classes "top" and "bot" with corresponding operations "top" and "bot"
   108 in theory Orderings;  instantiation of class "complete_lattice" requires
   109 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   110 
   111 * Changed definition lemma "less_fun_def" in order to provide an instance
   112 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   113 
   114 * Unified theorem tables for both code code generators.  Thus
   115 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   116 
   117 * Constants "undefined" and "default" replace "arbitrary".  Usually
   118 "undefined" is the right choice to replace "arbitrary", though logically
   119 there is no difference.  INCOMPATIBILITY.
   120 
   121 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   122 Posix processes.  Avoids potentially expensive forking of the ML
   123 process.  New thread-based implementation also works on non-Unix
   124 platforms (Cygwin).  Provers are no longer hardwired, but defined
   125 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   126 commands are covered in the isar-ref manual
   127 
   128 * Wrapper scripts for remote SystemOnTPTP service allows to use
   129 sledgehammer without local ATP installation (Vampire etc.).  See also
   130 ISABELLE_HOME/contrib/SystemOnTPTP and the VAMPIRE_HOME setting
   131 variable.  Other provers may be included via suitable ML wrappers, see
   132 also src/HOL/ATP_Linkup.thy.
   133 
   134 * Normalization by evaluation now allows non-leftlinear equations.
   135 Declare with attribute [code nbe].
   136 
   137 * Command "value" now integrates different evaluation
   138 mechanisms.  The result of the first successful evaluation mechanism
   139 is printed.  In square brackets a particular named evaluation
   140 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   141 further src/HOL/ex/Eval_Examples.thy.
   142 
   143 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   144 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   145 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   146 
   147 * HOL/Orderings: added class "preorder" as superclass of "order".
   148 INCOMPATIBILITY: Instantiation proofs for order, linorder
   149 etc. slightly changed.  Some theorems named order_class.* now named
   150 preorder_class.*.
   151 
   152 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   153 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   154 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   155 of lemmas from Divides has been generalized from nat to class
   156 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   157 renames resulting from duplicate elimination:
   158 
   159     dvd_def_mod ~>          dvd_eq_mod_eq_0
   160     zero_dvd_iff ~>         dvd_0_left_iff
   161     dvd_0 ~>                dvd_0_right
   162     DIVISION_BY_ZERO_DIV ~> div_by_0
   163     DIVISION_BY_ZERO_MOD ~> mod_by_0
   164     mult_div ~>             div_mult_self2_is_id
   165     mult_mod ~>             mod_mult_self2_is_0
   166 
   167 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   168 zlcm (for int); carried together from various gcd/lcm developements in
   169 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   170 corresponding theorems renamed accordingly.  INCOMPATIBILY.  To
   171 recover tupled syntax, use syntax declarations like:
   172 
   173     hide (open) const gcd
   174     abbreviation gcd where
   175       "gcd == (%(a, b). GCD.gcd a b)"
   176     notation (output)
   177       GCD.gcd ("gcd '(_, _')")
   178 
   179 (analogously for lcm, zgcd, zlcm).
   180 
   181 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   182 
   183 * New ML antiquotation @{code}: takes constant as argument, generates
   184 corresponding code in background and inserts name of the corresponding
   185 resulting ML value/function/datatype constructor binding in place.
   186 All occurrences of @{code} with a single ML block are generated
   187 simultaneously.  Provides a generic and safe interface for
   188 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   189 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   190 application.  In future you ought refrain from ad-hoc compiling
   191 generated SML code on the ML toplevel.  Note that (for technical
   192 reasons) @{code} cannot refer to constants for which user-defined
   193 serializations are set.  Refer to the corresponding ML counterpart
   194 directly in that cases.
   195 
   196 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   197 Complex_Main.thy remain as they are.
   198 
   199 * New image HOL-Plain provides a minimal HOL with the most important
   200 tools available (inductive, datatype, primrec, ...).  By convention
   201 the corresponding theory Plain should be ancestor of every further
   202 (library) theory.  Some library theories now have ancestor Plain
   203 (instead of Main), thus theory Main occasionally has to be imported
   204 explicitly.
   205 
   206 * The metis method now fails in the usual manner, rather than raising
   207 an exception, if it determines that it cannot prove the theorem.
   208 
   209 * The metis method no longer fails because the theorem is too trivial
   210 (contains the empty clause).
   211 
   212 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   213 as the structured Isar versions "cases" and "induct", cf. the
   214 corresponding "cases" and "induct" attributes.  Mutual induction rules
   215 are now presented as a list of individual projections
   216 (e.g. foo_bar.inducts for types foo and bar); the old format with
   217 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   218 rare situations a different rule is selected --- notably nested tuple
   219 elimination instead of former prod.exhaust: use explicit (case_tac t
   220 rule: prod.exhaust) here.
   221 
   222 * Attributes "cases", "induct", "coinduct" support "del" option.
   223 
   224 * Removed fact "case_split_thm", which duplicates "case_split".
   225 
   226 * Command 'rep_datatype': instead of theorem names the command now
   227 takes a list of terms denoting the constructors of the type to be
   228 represented as datatype.  The characteristic theorems have to be
   229 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   230 have disappeared in favour of existing ones:
   231 
   232     unit_induct                 ~> unit.induct
   233     prod_induct                 ~> prod.induct
   234     sum_induct                  ~> sum.induct
   235     Suc_Suc_eq                  ~> nat.inject
   236     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   237 
   238 * Library/Nat_Infinity: added addition, numeral syntax and more
   239 instantiations for algebraic structures.  Removed some duplicate
   240 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   241 
   242 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   243 menu.
   244 
   245 
   246 *** HOL-Algebra ***
   247 
   248 * New locales for orders and lattices where the equivalence relation
   249   is not restricted to equality.  INCOMPATIBILITY: all order and
   250   lattice locales use a record structure with field eq for the
   251   equivalence.
   252 
   253 * New theory of factorial domains.
   254 
   255 * Units_l_inv and Units_r_inv are now simprules by default.
   256 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   257 and/or r_inv will now also require deletion of these lemmas.
   258 
   259 * Renamed the following theorems.  INCOMPATIBILITY.
   260 UpperD ~> Upper_memD
   261 LowerD ~> Lower_memD
   262 least_carrier ~> least_closed
   263 greatest_carrier ~> greatest_closed
   264 greatest_Lower_above ~> greatest_Lower_below
   265 one_zero ~> carrier_one_zero
   266 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   267 
   268 
   269 *** HOL-NSA ***
   270 
   271 * Created new image HOL-NSA, containing theories of nonstandard
   272 analysis which were previously part of HOL-Complex.  Entry point
   273 Hyperreal.thy remains valid, but theories formerly using
   274 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   275 
   276 
   277 *** ZF ***
   278 
   279 * Proof of Zorn's Lemma for partial orders.
   280 
   281 
   282 *** ML ***
   283 
   284 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   285 to 'a -> thm, while results are always tagged with an authentic oracle
   286 name.  The Isar command 'oracle' is now polymorphic, no argument type
   287 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   288 accordingly.  Note that extra performance may be gained by producing
   289 the cterm carefully, avoiding slow Thm.cterm_of.
   290 
   291 * ML bindings produced via Isar commands are stored within the Isar
   292 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   293 become thread-safe and work with undo as expected (concerning
   294 top-level bindings, not side-effects on global references).
   295 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   296 compiler at runtime; really global bindings need to be given outside a
   297 theory. [Poly/ML 5.2 or later]
   298 
   299 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   300 context. Top-level ML bindings are stored within the proof context in
   301 a purely sequential fashion, disregarding the nested proof structure.
   302 ML bindings introduced by 'ML_prf' are discarded at the end of the
   303 proof.  [Poly/ML 5.2 or later]
   304 
   305 * Generic Toplevel.add_hook interface allows to analyze the result of
   306 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   307 for theorem dependency output of transactions resulting in a new
   308 theory state.
   309 
   310 * Name bindings in higher specification mechanisms (notably
   311 LocalTheory.define, LocalTheory.note, and derived packages) are now
   312 formalized as type Name.binding, replacing old bstring.
   313 INCOMPATIBILITY, need to wrap strings via Name.binding function, see
   314 also Name.name_of.  Packages should pass name bindings given by the
   315 user to underlying specification mechanisms; this enables precise
   316 tracking of source positions, for example.
   317 
   318 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   319 LocalTheory.note etc.) now refer to the *full* internal name, not the
   320 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   321 
   322 * Rules and tactics that read instantiations (read_instantiate,
   323 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   324 context, which is required for parsing and type-checking.  Moreover,
   325 the variables are specified as plain indexnames, not string encodings
   326 thereof.  INCOMPATIBILITY.
   327 
   328 * Disposed old type and term read functions (Sign.read_def_typ,
   329 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   330 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   331 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   332 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   333 resort for legacy applications.
   334 
   335 * Antiquotations: block-structured compilation context indicated by
   336 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   337 
   338   @{let ?pat = term}                      - term abbreviation (HO matching)
   339   @{note name = fact}                     - fact abbreviation
   340   @{thm fact}                             - singleton fact (with attributes)
   341   @{thms fact}                            - general fact (with attributes)
   342   @{lemma prop by method}                 - singleton goal
   343   @{lemma prop by meth1 meth2}            - singleton goal
   344   @{lemma prop1 ... propN by method}      - general goal
   345   @{lemma prop1 ... propN by meth1 meth2} - general goal
   346   @{lemma (open) ...}                     - open derivation
   347 
   348 
   349 *** System ***
   350 
   351 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   352 Poly/ML 5.2.1 or later.
   353 
   354 * The Isabelle "emacs" tool provides a specific interface to invoke
   355 Proof General / Emacs, with more explicit failure if that is not
   356 installed (the old isabelle-interface script silently falls back on
   357 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   358 installation location of the Proof General distribution.
   359 
   360 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   361 the Isabelle process into a JVM/Scala application.  See
   362 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   363 process wrapper has been discontinued.)
   364 
   365 * Status messages (with exact source position information) are
   366 emitted, if proper markup print mode is enabled.  This allows
   367 user-interface components to provide detailed feedback on internal
   368 prover operations.
   369 
   370 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   371 
   372 
   373 
   374 New in Isabelle2008 (June 2008)
   375 -------------------------------
   376 
   377 *** General ***
   378 
   379 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   380 and updated, with formally checked references as hyperlinks.
   381 
   382 * Theory loader: use_thy (and similar operations) no longer set the
   383 implicit ML context, which was occasionally hard to predict and in
   384 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   385 provides a proper context already.
   386 
   387 * Theory loader: old-style ML proof scripts being *attached* to a thy
   388 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   389 'use' within a theory file will do the job.
   390 
   391 * Name space merge now observes canonical order, i.e. the second space
   392 is inserted into the first one, while existing entries in the first
   393 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   394 swap theory imports.
   395 
   396 * Syntax: symbol \<chi> is now considered a letter.  Potential
   397 INCOMPATIBILITY in identifier syntax etc.
   398 
   399 * Outer syntax: string tokens no longer admit escaped white space,
   400 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   401 white space without escapes.
   402 
   403 * Outer syntax: string tokens may contain arbitrary character codes
   404 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   405 "foo_bar".
   406 
   407 
   408 *** Pure ***
   409 
   410 * Context-dependent token translations.  Default setup reverts locally
   411 fixed variables, and adds hilite markup for undeclared frees.
   412 
   413 * Unused theorems can be found using the new command 'unused_thms'.
   414 There are three ways of invoking it:
   415 
   416 (1) unused_thms
   417      Only finds unused theorems in the current theory.
   418 
   419 (2) unused_thms thy_1 ... thy_n -
   420      Finds unused theorems in the current theory and all of its ancestors,
   421      excluding the theories thy_1 ... thy_n and all of their ancestors.
   422 
   423 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   424      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   425      their ancestors, excluding the theories thy_1 ... thy_n and all of
   426      their ancestors.
   427 
   428 In order to increase the readability of the list produced by
   429 unused_thms, theorems that have been created by a particular instance
   430 of a theory command such as 'inductive' or 'function' are considered
   431 to belong to the same "group", meaning that if at least one theorem in
   432 this group is used, the other theorems in the same group are no longer
   433 reported as unused.  Moreover, if all theorems in the group are
   434 unused, only one theorem in the group is displayed.
   435 
   436 Note that proof objects have to be switched on in order for
   437 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   438 usually the case when using Proof General with the default settings).
   439 
   440 * Authentic naming of facts disallows ad-hoc overwriting of previous
   441 theorems within the same name space.  INCOMPATIBILITY, need to remove
   442 duplicate fact bindings, or even accidental fact duplications.  Note
   443 that tools may maintain dynamically scoped facts systematically, using
   444 PureThy.add_thms_dynamic.
   445 
   446 * Command 'hide' now allows to hide from "fact" name space as well.
   447 
   448 * Eliminated destructive theorem database, simpset, claset, and
   449 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   450 update of theories within ML code.
   451 
   452 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   453 INCOMPATIBILITY, object-logics depending on former Pure require
   454 additional setup PureThy.old_appl_syntax_setup; object-logics
   455 depending on former CPure need to refer to Pure.
   456 
   457 * Commands 'use' and 'ML' are now purely functional, operating on
   458 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   459 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   460 INCOMPATIBILITY.
   461 
   462 * Command 'setup': discontinued implicit version with ML reference.
   463 
   464 * Instantiation target allows for simultaneous specification of class
   465 instance operations together with an instantiation proof.
   466 Type-checking phase allows to refer to class operations uniformly.
   467 See src/HOL/Complex/Complex.thy for an Isar example and
   468 src/HOL/Library/Eval.thy for an ML example.
   469 
   470 * Indexing of literal facts: be more serious about including only
   471 facts from the visible specification/proof context, but not the
   472 background context (locale etc.).  Affects `prop` notation and method
   473 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   474 situations.
   475 
   476 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   477 "(open)" option, which used to expose internal bound variables to the
   478 proof text.
   479 
   480 * Isar statements: removed obsolete case "rule_context".
   481 INCOMPATIBILITY, better use explicit fixes/assumes.
   482 
   483 * Locale proofs: default proof step now includes 'unfold_locales';
   484 hence 'proof' without argument may be used to unfold locale
   485 predicates.
   486 
   487 
   488 *** Document preparation ***
   489 
   490 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   491 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   492 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   493 spot); renamed link color from "darkblue" to "linkcolor" (default
   494 value unchanged, can be redefined via \definecolor); no longer sets
   495 "a4paper" option (unnecessary or even intrusive).
   496 
   497 * Antiquotation @{lemma A method} proves proposition A by the given
   498 method (either a method name or a method name plus (optional) method
   499 arguments in parentheses) and prints A just like @{prop A}.
   500 
   501 
   502 *** HOL ***
   503 
   504 * New primrec package.  Specification syntax conforms in style to
   505 definition/function/....  No separate induction rule is provided.  The
   506 "primrec" command distinguishes old-style and new-style specifications
   507 by syntax.  The former primrec package is now named OldPrimrecPackage.
   508 When adjusting theories, beware: constants stemming from new-style
   509 primrec specifications have authentic syntax.
   510 
   511 * Metis prover is now an order of magnitude faster, and also works
   512 with multithreading.
   513 
   514 * Metis: the maximum number of clauses that can be produced from a
   515 theorem is now given by the attribute max_clauses.  Theorems that
   516 exceed this number are ignored, with a warning printed.
   517 
   518 * Sledgehammer no longer produces structured proofs by default. To
   519 enable, declare [[sledgehammer_full = true]].  Attributes
   520 reconstruction_modulus, reconstruction_sorts renamed
   521 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   522 
   523 * Method "induct_scheme" derives user-specified induction rules
   524 from well-founded induction and completeness of patterns. This factors
   525 out some operations that are done internally by the function package
   526 and makes them available separately.  See
   527 src/HOL/ex/Induction_Scheme.thy for examples.
   528 
   529 * More flexible generation of measure functions for termination
   530 proofs: Measure functions can be declared by proving a rule of the
   531 form "is_measure f" and giving it the [measure_function] attribute.
   532 The "is_measure" predicate is logically meaningless (always true), and
   533 just guides the heuristic.  To find suitable measure functions, the
   534 termination prover sets up the goal "is_measure ?f" of the appropriate
   535 type and generates all solutions by prolog-style backwards proof using
   536 the declared rules.
   537 
   538 This setup also deals with rules like 
   539 
   540   "is_measure f ==> is_measure (list_size f)"
   541 
   542 which accommodates nested datatypes that recurse through lists.
   543 Similar rules are predeclared for products and option types.
   544 
   545 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   546 
   547   INCOMPATIBILITIES:
   548 
   549   - Definitions of overloaded constants on sets have to be replaced by
   550     definitions on => and bool.
   551 
   552   - Some definitions of overloaded operators on sets can now be proved
   553     using the definitions of the operators on => and bool.  Therefore,
   554     the following theorems have been renamed:
   555 
   556       subset_def   -> subset_eq
   557       psubset_def  -> psubset_eq
   558       set_diff_def -> set_diff_eq
   559       Compl_def    -> Compl_eq
   560       Sup_set_def  -> Sup_set_eq
   561       Inf_set_def  -> Inf_set_eq
   562       sup_set_def  -> sup_set_eq
   563       inf_set_def  -> inf_set_eq
   564 
   565   - Due to the incompleteness of the HO unification algorithm, some
   566     rules such as subst may require manual instantiation, if some of
   567     the unknowns in the rule is a set.
   568 
   569   - Higher order unification and forward proofs:
   570     The proof pattern
   571 
   572       have "P (S::'a set)" <...>
   573       then have "EX S. P S" ..
   574 
   575     no longer works (due to the incompleteness of the HO unification
   576     algorithm) and must be replaced by the pattern
   577 
   578       have "EX S. P S"
   579       proof
   580         show "P S" <...>
   581       qed
   582 
   583   - Calculational reasoning with subst (or similar rules):
   584     The proof pattern
   585 
   586       have "P (S::'a set)" <...>
   587       also have "S = T" <...>
   588       finally have "P T" .
   589 
   590     no longer works (for similar reasons as the previous example) and
   591     must be replaced by something like
   592 
   593       have "P (S::'a set)" <...>
   594       moreover have "S = T" <...>
   595       ultimately have "P T" by simp
   596 
   597   - Tactics or packages written in ML code:
   598     Code performing pattern matching on types via
   599 
   600       Type ("set", [T]) => ...
   601 
   602     must be rewritten. Moreover, functions like strip_type or
   603     binder_types no longer return the right value when applied to a
   604     type of the form
   605 
   606       T1 => ... => Tn => U => bool
   607 
   608     rather than
   609 
   610       T1 => ... => Tn => U set
   611 
   612 * Merged theories Wellfounded_Recursion, Accessible_Part and
   613 Wellfounded_Relations to theory Wellfounded.
   614 
   615 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   616 
   617 * Class finite no longer treats UNIV as class parameter.  Use class
   618 enum from theory Library/Enum instead to achieve a similar effect.
   619 INCOMPATIBILITY.
   620 
   621 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   622 and "Cons".  INCOMPATIBILITY.
   623 
   624 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   625 Potential INCOMPATIBILITY.
   626 
   627 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   628 injective_fst_snd removed, use split_eta and prod_eqI instead.
   629 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   630 
   631 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   632 the same name in theory Orderings:
   633 
   634   less_trans
   635   less_linear
   636   le_imp_less_or_eq
   637   le_less_trans
   638   less_le_trans
   639   less_not_sym
   640   less_asym
   641 
   642 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   643 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   644 and different variable names.
   645 
   646 * Library/Option_ord.thy: Canonical order on option type.
   647 
   648 * Library/RBT.thy: Red-black trees, an efficient implementation of
   649 finite maps.
   650 
   651 * Library/Countable.thy: Type class for countable types.
   652 
   653 * Theory Int: The representation of numerals has changed.  The infix
   654 operator BIT and the bit datatype with constructors B0 and B1 have
   655 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   656 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   657 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   658 accordingly.
   659 
   660 * Theory Nat: definition of <= and < on natural numbers no longer
   661 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   662 le_def and less_def have disappeared.  Consider lemmas not_less
   663 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   664 
   665 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   666 (whose purpose mainly is for various fold_set functionals) have been
   667 abandoned in favor of the existing algebraic classes
   668 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   669 lower_semilattice (resp. upper_semilattice) and linorder.
   670 INCOMPATIBILITY.
   671 
   672 * Theory Transitive_Closure: induct and cases rules now declare proper
   673 case_names ("base" and "step").  INCOMPATIBILITY.
   674 
   675 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   676 lattices.  The form set-specific version is available as
   677 Inductive.lfp_ordinal_induct_set.
   678 
   679 * Renamed theorems "power.simps" to "power_int.simps".
   680 INCOMPATIBILITY.
   681 
   682 * Class semiring_div provides basic abstract properties of semirings
   683 with division and modulo operations.  Subsumes former class dvd_mod.
   684 
   685 * Merged theories IntDef, Numeral and IntArith into unified theory
   686 Int.  INCOMPATIBILITY.
   687 
   688 * Theory Library/Code_Index: type "index" now represents natural
   689 numbers rather than integers.  INCOMPATIBILITY.
   690 
   691 * New class "uminus" with operation "uminus" (split of from class
   692 "minus" which now only has operation "minus", binary).
   693 INCOMPATIBILITY.
   694 
   695 * Constants "card", "internal_split", "option_map" now with authentic
   696 syntax.  INCOMPATIBILITY.
   697 
   698 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   699 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   700 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   701 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   702 Sup_set_def, le_def, less_def, option_map_def now with object
   703 equality.  INCOMPATIBILITY.
   704 
   705 * Records. Removed K_record, and replaced it by pure lambda term
   706 %x. c. The simplifier setup is now more robust against eta expansion.
   707 INCOMPATIBILITY: in cases explicitly referring to K_record.
   708 
   709 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   710 
   711 * Library/ListVector: new theory of arithmetic vector operations.
   712 
   713 * Library/Order_Relation: new theory of various orderings as sets of
   714 pairs.  Defines preorders, partial orders, linear orders and
   715 well-orders on sets and on types.
   716 
   717 
   718 *** ZF ***
   719 
   720 * Renamed some theories to allow to loading both ZF and HOL in the
   721 same session:
   722 
   723   Datatype  -> Datatype_ZF
   724   Inductive -> Inductive_ZF
   725   Int       -> Int_ZF
   726   IntDiv    -> IntDiv_ZF
   727   Nat       -> Nat_ZF
   728   List      -> List_ZF
   729   Main      -> Main_ZF
   730 
   731 INCOMPATIBILITY: ZF theories that import individual theories below
   732 Main might need to be adapted.  Regular theory Main is still
   733 available, as trivial extension of Main_ZF.
   734 
   735 
   736 *** ML ***
   737 
   738 * ML within Isar: antiquotation @{const name} or @{const
   739 name(typargs)} produces statically-checked Const term.
   740 
   741 * Functor NamedThmsFun: data is available to the user as dynamic fact
   742 (of the same name).  Removed obsolete print command.
   743 
   744 * Removed obsolete "use_legacy_bindings" function.
   745 
   746 * The ``print mode'' is now a thread-local value derived from a global
   747 template (the former print_mode reference), thus access becomes
   748 non-critical.  The global print_mode reference is for session
   749 management only; user-code should use print_mode_value,
   750 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   751 
   752 * Functions system/system_out provide a robust way to invoke external
   753 shell commands, with propagation of interrupts (requires Poly/ML 5.2).
   754 Do not use OS.Process.system etc. from the basis library!
   755 
   756 
   757 *** System ***
   758 
   759 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   760 in accordance with Proof General 3.7, which prefers GNU emacs.
   761 
   762 * isatool tty runs Isabelle process with plain tty interaction;
   763 optional line editor may be specified via ISABELLE_LINE_EDITOR
   764 setting, the default settings attempt to locate "ledit" and "rlwrap".
   765 
   766 * isatool browser now works with Cygwin as well, using general
   767 "javapath" function defined in Isabelle process environment.
   768 
   769 * YXML notation provides a simple and efficient alternative to
   770 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
   771 isatool yxml as described in the Isabelle system manual.
   772 
   773 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   774 provides general wrapper for managing an Isabelle process in a robust
   775 fashion, with ``cooked'' output from stdin/stderr.
   776 
   777 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   778 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   779 
   780 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
   781 way of changing the user's settings is via
   782 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   783 script.
   784 
   785 * Multithreading.max_threads := 0 refers to the number of actual CPU
   786 cores of the underlying machine, which is a good starting point for
   787 optimal performance tuning.  The corresponding usedir option -M allows
   788 "max" as an alias for "0".  WARNING: does not work on certain versions
   789 of Mac OS (with Poly/ML 5.1).
   790 
   791 * isabelle-process: non-ML sessions are run with "nice", to reduce the
   792 adverse effect of Isabelle flooding interactive front-ends (notably
   793 ProofGeneral / XEmacs).
   794 
   795 
   796 
   797 New in Isabelle2007 (November 2007)
   798 -----------------------------------
   799 
   800 *** General ***
   801 
   802 * More uniform information about legacy features, notably a
   803 warning/error of "Legacy feature: ...", depending on the state of the
   804 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   805 legacy features will disappear eventually.
   806 
   807 * Theory syntax: the header format ``theory A = B + C:'' has been
   808 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   809 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   810 
   811 * Theory syntax: the old non-Isar theory file format has been
   812 discontinued altogether.  Note that ML proof scripts may still be used
   813 with Isar theories; migration is usually quite simple with the ML
   814 function use_legacy_bindings.  INCOMPATIBILITY.
   815 
   816 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   817 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   818 quotes.
   819 
   820 * Theory loader: be more serious about observing the static theory
   821 header specifications (including optional directories), but not the
   822 accidental file locations of previously successful loads.  The strict
   823 update policy of former update_thy is now already performed by
   824 use_thy, so the former has been removed; use_thys updates several
   825 theories simultaneously, just as 'imports' within a theory header
   826 specification, but without merging the results.  Potential
   827 INCOMPATIBILITY: may need to refine theory headers and commands
   828 ROOT.ML which depend on load order.
   829 
   830 * Theory loader: optional support for content-based file
   831 identification, instead of the traditional scheme of full physical
   832 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   833 (cf. the system manual).  The new scheme allows to work with
   834 non-finished theories in persistent session images, such that source
   835 files may be moved later on without requiring reloads.
   836 
   837 * Theory loader: old-style ML proof scripts being *attached* to a thy
   838 file (with the same base name as the theory) are considered a legacy
   839 feature, which will disappear eventually. Even now, the theory loader
   840 no longer maintains dependencies on such files.
   841 
   842 * Syntax: the scope for resolving ambiguities via type-inference is
   843 now limited to individual terms, instead of whole simultaneous
   844 specifications as before. This greatly reduces the complexity of the
   845 syntax module and improves flexibility by separating parsing and
   846 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   847 'fixes' etc.) are required in rare situations.
   848 
   849 * Syntax: constants introduced by new-style packages ('definition',
   850 'abbreviation' etc.) are passed through the syntax module in
   851 ``authentic mode''. This means that associated mixfix annotations
   852 really stick to such constants, independently of potential name space
   853 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   854 trees are represented slightly differently, may need to adapt syntax
   855 translations accordingly. Use CONST marker in 'translations' and
   856 @{const_syntax} antiquotation in 'parse_translation' etc.
   857 
   858 * Legacy goal package: reduced interface to the bare minimum required
   859 to keep existing proof scripts running.  Most other user-level
   860 functions are now part of the OldGoals structure, which is *not* open
   861 by default (consider isatool expandshort before open OldGoals).
   862 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   863 these tend to cause confusion about the actual goal (!) context being
   864 used here, which is not necessarily the same as the_context().
   865 
   866 * Command 'find_theorems': supports "*" wild-card in "name:"
   867 criterion; "with_dups" option.  Certain ProofGeneral versions might
   868 support a specific search form (see ProofGeneral/CHANGES).
   869 
   870 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   871 by default, which means that "prems" (and also "fixed variables") are
   872 suppressed from proof state output.  Note that the ProofGeneral
   873 settings mechanism allows to change and save options persistently, but
   874 older versions of Isabelle will fail to start up if a negative prems
   875 limit is imposed.
   876 
   877 * Local theory targets may be specified by non-nested blocks of
   878 ``context/locale/class ... begin'' followed by ``end''.  The body may
   879 contain definitions, theorems etc., including any derived mechanism
   880 that has been implemented on top of these primitives.  This concept
   881 generalizes the existing ``theorem (in ...)'' towards more versatility
   882 and scalability.
   883 
   884 * Proof General interface: proper undo of final 'end' command;
   885 discontinued Isabelle/classic mode (ML proof scripts).
   886 
   887 
   888 *** Document preparation ***
   889 
   890 * Added antiquotation @{theory name} which prints the given name,
   891 after checking that it refers to a valid ancestor theory in the
   892 current context.
   893 
   894 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   895 check the given source text as ML type/structure, printing verbatim.
   896 
   897 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   898 "c args == rhs" given in the current context.  (Any number of
   899 arguments may be given on the LHS.)
   900 
   901 
   902 *** Pure ***
   903 
   904 * The 'class' package offers a combination of axclass and locale to
   905 achieve Haskell-like type classes in Isabelle.  Definitions and
   906 theorems within a class context produce both relative results (with
   907 implicit parameters according to the locale context), and polymorphic
   908 constants with qualified polymorphism (according to the class
   909 context).  Within the body context of a 'class' target, a separate
   910 syntax layer ("user space type system") takes care of converting
   911 between global polymorphic consts and internal locale representation.
   912 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   913 "isatool doc classes" provides a tutorial.
   914 
   915 * Generic code generator framework allows to generate executable
   916 code for ML and Haskell (including Isabelle classes).  A short usage
   917 sketch:
   918 
   919     internal compilation:
   920         export_code <list of constants (term syntax)> in SML
   921     writing SML code to a file:
   922         export_code <list of constants (term syntax)> in SML <filename>
   923     writing OCaml code to a file:
   924         export_code <list of constants (term syntax)> in OCaml <filename>
   925     writing Haskell code to a bunch of files:
   926         export_code <list of constants (term syntax)> in Haskell <filename>
   927 
   928     evaluating closed propositions to True/False using code generation:
   929         method ``eval''
   930 
   931 Reasonable default setup of framework in HOL.
   932 
   933 Theorem attributs for selecting and transforming function equations theorems:
   934 
   935     [code fun]:        select a theorem as function equation for a specific constant
   936     [code fun del]:    deselect a theorem as function equation for a specific constant
   937     [code inline]:     select an equation theorem for unfolding (inlining) in place
   938     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   939 
   940 User-defined serializations (target in {SML, OCaml, Haskell}):
   941 
   942     code_const <and-list of constants (term syntax)>
   943       {(target) <and-list of const target syntax>}+
   944 
   945     code_type <and-list of type constructors>
   946       {(target) <and-list of type target syntax>}+
   947 
   948     code_instance <and-list of instances>
   949       {(target)}+
   950         where instance ::= <type constructor> :: <class>
   951 
   952     code_class <and_list of classes>
   953       {(target) <and-list of class target syntax>}+
   954         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   955 
   956 code_instance and code_class only are effective to target Haskell.
   957 
   958 For example usage see src/HOL/ex/Codegenerator.thy and
   959 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   960 generation from Isabelle/HOL theories is available via "isatool doc
   961 codegen".
   962 
   963 * Code generator: consts in 'consts_code' Isar commands are now
   964 referred to by usual term syntax (including optional type
   965 annotations).
   966 
   967 * Command 'no_translations' removes translation rules from theory
   968 syntax.
   969 
   970 * Overloaded definitions are now actually checked for acyclic
   971 dependencies.  The overloading scheme is slightly more general than
   972 that of Haskell98, although Isabelle does not demand an exact
   973 correspondence to type class and instance declarations.
   974 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   975 exotic versions of overloading -- at the discretion of the user!
   976 
   977 Polymorphic constants are represented via type arguments, i.e. the
   978 instantiation that matches an instance against the most general
   979 declaration given in the signature.  For example, with the declaration
   980 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   981 as c(nat).  Overloading is essentially simultaneous structural
   982 recursion over such type arguments.  Incomplete specification patterns
   983 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   984 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   985 Command 'print_theory' outputs the normalized system of recursive
   986 equations, see section "definitions".
   987 
   988 * Configuration options are maintained within the theory or proof
   989 context (with name and type bool/int/string), providing a very simple
   990 interface to a poor-man's version of general context data.  Tools may
   991 declare options in ML (e.g. using Attrib.config_int) and then refer to
   992 these values using Config.get etc.  Users may change options via an
   993 associated attribute of the same name.  This form of context
   994 declaration works particularly well with commands 'declare' or
   995 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   996 very easy to avoid global references, which would not observe Isar
   997 toplevel undo/redo and fail to work with multithreading.
   998 
   999 Various global ML references of Pure and HOL have been turned into
  1000 configuration options:
  1001 
  1002   Unify.search_bound		unify_search_bound
  1003   Unify.trace_bound		unify_trace_bound
  1004   Unify.trace_simp		unify_trace_simp
  1005   Unify.trace_types		unify_trace_types
  1006   Simplifier.simp_depth_limit	simp_depth_limit
  1007   Blast.depth_limit		blast_depth_limit
  1008   DatatypeProp.dtK		datatype_distinctness_limit
  1009   fast_arith_neq_limit  	fast_arith_neq_limit
  1010   fast_arith_split_limit	fast_arith_split_limit
  1011 
  1012 * Named collections of theorems may be easily installed as context
  1013 data using the functor NamedThmsFun (see also
  1014 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1015 attributes; there is also a toplevel print command.  This facility is
  1016 just a common case of general context data, which is the preferred way
  1017 for anything more complex than just a list of facts in canonical
  1018 order.
  1019 
  1020 * Isar: command 'declaration' augments a local theory by generic
  1021 declaration functions written in ML.  This enables arbitrary content
  1022 being added to the context, depending on a morphism that tells the
  1023 difference of the original declaration context wrt. the application
  1024 context encountered later on.
  1025 
  1026 * Isar: proper interfaces for simplification procedures.  Command
  1027 'simproc_setup' declares named simprocs (with match patterns, and body
  1028 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1029 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1030 
  1031 * Isar: an extra pair of brackets around attribute declarations
  1032 abbreviates a theorem reference involving an internal dummy fact,
  1033 which will be ignored later --- only the effect of the attribute on
  1034 the background context will persist.  This form of in-place
  1035 declarations is particularly useful with commands like 'declare' and
  1036 'using', for example ``have A using [[simproc a]] by simp''.
  1037 
  1038 * Isar: method "assumption" (and implicit closing of subproofs) now
  1039 takes simple non-atomic goal assumptions into account: after applying
  1040 an assumption as a rule the resulting subgoals are solved by atomic
  1041 assumption steps.  This is particularly useful to finish 'obtain'
  1042 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1043 without referring to the original premise "!!x. P x ==> thesis" in the
  1044 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1045 more permissive.
  1046 
  1047 * Isar: implicit use of prems from the Isar proof context is
  1048 considered a legacy feature.  Common applications like ``have A .''
  1049 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1050 referencing facts explicitly here improves readability and
  1051 maintainability of proof texts.
  1052 
  1053 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1054 the obtained context from the course of reasoning!  For example:
  1055 
  1056   assume "EX x y. A x & B y"   -- "any previous fact"
  1057   then guess x and y by clarify
  1058 
  1059 This technique is potentially adventurous, depending on the facts and
  1060 proof tools being involved here.
  1061 
  1062 * Isar: known facts from the proof context may be specified as literal
  1063 propositions, using ASCII back-quote syntax.  This works wherever
  1064 named facts used to be allowed so far, in proof commands, proof
  1065 methods, attributes etc.  Literal facts are retrieved from the context
  1066 according to unification of type and term parameters.  For example,
  1067 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1068 theorems in the current context, then these are valid literal facts:
  1069 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1070 
  1071 There is also a proof method "fact" which does the same composition
  1072 for explicit goal states, e.g. the following proof texts coincide with
  1073 certain special cases of literal facts:
  1074 
  1075   have "A" by fact                 ==  note `A`
  1076   have "A ==> B" by fact           ==  note `A ==> B`
  1077   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1078   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1079 
  1080 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1081 outer syntax.  Thus symbolic identifiers may be used without
  1082 additional white space in declarations like this: ``assume *: A''.
  1083 
  1084 * Isar: 'print_facts' prints all local facts of the current context,
  1085 both named and unnamed ones.
  1086 
  1087 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1088 
  1089   def x == "t" and y == "u"
  1090 
  1091 * Isar: added command 'unfolding', which is structurally similar to
  1092 'using', but affects both the goal state and facts by unfolding given
  1093 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1094 'unfolded' attribute may be replaced by first-class proof text.
  1095 
  1096 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1097 and command 'unfolding' now all support object-level equalities
  1098 (potentially conditional).  The underlying notion of rewrite rule is
  1099 analogous to the 'rule_format' attribute, but *not* that of the
  1100 Simplifier (which is usually more generous).
  1101 
  1102 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1103 premises of a theorem by n. Useful in conjunction with drule.
  1104 
  1105 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1106 method expression within a sandbox consisting of the first N
  1107 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1108 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1109 simplifies all new goals that emerge from applying rule foo to the
  1110 originally first one.
  1111 
  1112 * Isar: schematic goals are no longer restricted to higher-order
  1113 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1114 expected.
  1115 
  1116 * Isar: the conclusion of a long theorem statement is now either
  1117 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1118 (essentially a disjunction of cases with local parameters and
  1119 assumptions).  The latter allows to express general elimination rules
  1120 adequately; in this notation common elimination rules look like this:
  1121 
  1122   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1123     assumes "EX x. P x"
  1124     obtains x where "P x"
  1125 
  1126   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1127     assumes "A & B"
  1128     obtains A and B
  1129 
  1130   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1131     assumes "A | B"
  1132     obtains
  1133       A
  1134     | B
  1135 
  1136 The subsequent classical rules even refer to the formal "thesis"
  1137 explicitly:
  1138 
  1139   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1140     obtains "~ thesis"
  1141 
  1142   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1143     obtains "thesis ==> something"
  1144 
  1145 The actual proof of an 'obtains' statement is analogous to that of the
  1146 Isar proof element 'obtain', only that there may be several cases.
  1147 Optional case names may be specified in parentheses; these will be
  1148 available both in the present proof and as annotations in the
  1149 resulting rule, for later use with the 'cases' method (cf. attribute
  1150 case_names).
  1151 
  1152 * Isar: the assumptions of a long theorem statement are available as
  1153 "assms" fact in the proof context.  This is more appropriate than the
  1154 (historical) "prems", which refers to all assumptions of the current
  1155 context, including those from the target locale, proof body etc.
  1156 
  1157 * Isar: 'print_statement' prints theorems from the current theory or
  1158 proof context in long statement form, according to the syntax of a
  1159 top-level lemma.
  1160 
  1161 * Isar: 'obtain' takes an optional case name for the local context
  1162 introduction rule (default "that").
  1163 
  1164 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1165 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1166 to occur.
  1167 
  1168 * Pure: syntax "CONST name" produces a fully internalized constant
  1169 according to the current context.  This is particularly useful for
  1170 syntax translations that should refer to internal constant
  1171 representations independently of name spaces.
  1172 
  1173 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1174 instead of "FOO ". This allows multiple binder declarations to coexist
  1175 in the same context.  INCOMPATIBILITY.
  1176 
  1177 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1178 primitive that also works in a locale context (both for constants and
  1179 fixed variables). Type declaration and internal syntactic representation
  1180 of given constants retrieved from the context. Likewise, the
  1181 'no_notation' command allows to remove given syntax annotations from the
  1182 current context.
  1183 
  1184 * Isar/locales: new derived specification elements 'axiomatization',
  1185 'definition', 'abbreviation', which support type-inference, admit
  1186 object-level specifications (equality, equivalence).  See also the
  1187 isar-ref manual.  Examples:
  1188 
  1189   axiomatization
  1190     eq  (infix "===" 50) where
  1191     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1192 
  1193   definition "f x y = x + y + 1"
  1194   definition g where "g x = f x x"
  1195 
  1196   abbreviation
  1197     neq  (infix "=!=" 50) where
  1198     "x =!= y == ~ (x === y)"
  1199 
  1200 These specifications may be also used in a locale context.  Then the
  1201 constants being introduced depend on certain fixed parameters, and the
  1202 constant name is qualified by the locale base name.  An internal
  1203 abbreviation takes care for convenient input and output, making the
  1204 parameters implicit and using the original short name.  See also
  1205 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1206 entities from a monomorphic theory.
  1207 
  1208 Presently, abbreviations are only available 'in' a target locale, but
  1209 not inherited by general import expressions.  Also note that
  1210 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1211 'translations' in common applications.  The "no_abbrevs" print mode
  1212 prevents folding of abbreviations in term output.
  1213 
  1214 Concrete syntax is attached to specified constants in internal form,
  1215 independently of name spaces.  The parse tree representation is
  1216 slightly different -- use 'notation' instead of raw 'syntax', and
  1217 'translations' with explicit "CONST" markup to accommodate this.
  1218 
  1219 * Pure/Isar: unified syntax for new-style specification mechanisms
  1220 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1221 full type inference and dummy patterns ("_").  For example:
  1222 
  1223   definition "K x _ = x"
  1224 
  1225   inductive conj for A B
  1226   where "A ==> B ==> conj A B"
  1227 
  1228 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1229 the current context.  Print mode "no_abbrevs" prevents inversion of
  1230 abbreviations on output.
  1231 
  1232 * Isar/locales: improved parameter handling: use of locales "var" and
  1233 "struct" no longer necessary; - parameter renamings are no longer
  1234 required to be injective.  For example, this allows to define
  1235 endomorphisms as locale endom = homom mult mult h.
  1236 
  1237 * Isar/locales: changed the way locales with predicates are defined.
  1238 Instead of accumulating the specification, the imported expression is
  1239 now an interpretation.  INCOMPATIBILITY: different normal form of
  1240 locale expressions.  In particular, in interpretations of locales with
  1241 predicates, goals repesenting already interpreted fragments are not
  1242 removed automatically.  Use methods `intro_locales' and
  1243 `unfold_locales'; see below.
  1244 
  1245 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1246 provide backward reasoning on locales predicates.  The methods are
  1247 aware of interpretations and discharge corresponding goals.
  1248 `intro_locales' is less aggressive then `unfold_locales' and does not
  1249 unfold predicates to assumptions.
  1250 
  1251 * Isar/locales: the order in which locale fragments are accumulated
  1252 has changed.  This enables to override declarations from fragments due
  1253 to interpretations -- for example, unwanted simp rules.
  1254 
  1255 * Isar/locales: interpretation in theories and proof contexts has been
  1256 extended.  One may now specify (and prove) equations, which are
  1257 unfolded in interpreted theorems.  This is useful for replacing
  1258 defined concepts (constants depending on locale parameters) by
  1259 concepts already existing in the target context.  Example:
  1260 
  1261   interpretation partial_order ["op <= :: [int, int] => bool"]
  1262     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1263 
  1264 Typically, the constant `partial_order.less' is created by a
  1265 definition specification element in the context of locale
  1266 partial_order.
  1267 
  1268 * Method "induct": improved internal context management to support
  1269 local fixes and defines on-the-fly. Thus explicit meta-level
  1270 connectives !!  and ==> are rarely required anymore in inductive goals
  1271 (using object-logic connectives for this purpose has been long
  1272 obsolete anyway). Common proof patterns are explained in
  1273 src/HOL/Induct/Common_Patterns.thy, see also
  1274 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1275 examples.
  1276 
  1277 * Method "induct": improved handling of simultaneous goals. Instead of
  1278 introducing object-level conjunction, the statement is now split into
  1279 several conclusions, while the corresponding symbolic cases are nested
  1280 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1281 see src/HOL/Induct/Common_Patterns.thy, for example.
  1282 
  1283 * Method "induct": mutual induction rules are now specified as a list
  1284 of rule sharing the same induction cases. HOL packages usually provide
  1285 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1286 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1287 mutual induction rules differently, i.e. like this:
  1288 
  1289   (induct rule: foo_bar.inducts)
  1290   (induct set: foo bar)
  1291   (induct pred: foo bar)
  1292   (induct type: foo bar)
  1293 
  1294 The ML function ProjectRule.projections turns old-style rules into the
  1295 new format.
  1296 
  1297 * Method "coinduct": dual of induction, see
  1298 src/HOL/Library/Coinductive_List.thy for various examples.
  1299 
  1300 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1301 considered a legacy feature.
  1302 
  1303 * Attribute "symmetric" produces result with standardized schematic
  1304 variables (index 0).  Potential INCOMPATIBILITY.
  1305 
  1306 * Simplifier: by default the simplifier trace only shows top level
  1307 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1308 default. Thus there is less danger of being flooded by the trace. The
  1309 trace indicates where parts have been suppressed.
  1310   
  1311 * Provers/classical: removed obsolete classical version of elim_format
  1312 attribute; classical elim/dest rules are now treated uniformly when
  1313 manipulating the claset.
  1314 
  1315 * Provers/classical: stricter checks to ensure that supplied intro,
  1316 dest and elim rules are well-formed; dest and elim rules must have at
  1317 least one premise.
  1318 
  1319 * Provers/classical: attributes dest/elim/intro take an optional
  1320 weight argument for the rule (just as the Pure versions).  Weights are
  1321 ignored by automated tools, but determine the search order of single
  1322 rule steps.
  1323 
  1324 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1325 where the body does not mention the bound variable.  Note that dummy
  1326 patterns implicitly depend on their context of bounds, which makes
  1327 "{_. _}" match any set comprehension as expected.  Potential
  1328 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1329 constant "_idtdummy" in the binding position.
  1330 
  1331 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1332 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1333 for example "A -> B" => "Pi A (%_. B)".
  1334 
  1335 * Pure: 'class_deps' command visualizes the subclass relation, using
  1336 the graph browser tool.
  1337 
  1338 * Pure: 'print_theory' now suppresses certain internal declarations by
  1339 default; use '!' option for full details.
  1340 
  1341 
  1342 *** HOL ***
  1343 
  1344 * Method "metis" proves goals by applying the Metis general-purpose
  1345 resolution prover (see also http://gilith.com/software/metis/).
  1346 Examples are in the directory MetisExamples.  WARNING: the
  1347 Isabelle/HOL-Metis integration does not yet work properly with
  1348 multi-threading.
  1349   
  1350 * Command 'sledgehammer' invokes external automatic theorem provers as
  1351 background processes.  It generates calls to the "metis" method if
  1352 successful. These can be pasted into the proof.  Users do not have to
  1353 wait for the automatic provers to return.  WARNING: does not really
  1354 work with multi-threading.
  1355 
  1356 * New "auto_quickcheck" feature tests outermost goal statements for
  1357 potential counter-examples.  Controlled by ML references
  1358 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1359 5000 milliseconds).  Fails silently if statements is outside of
  1360 executable fragment, or any other codgenerator problem occurs.
  1361 
  1362 * New constant "undefined" with axiom "undefined x = undefined".
  1363 
  1364 * Added class "HOL.eq", allowing for code generation with polymorphic
  1365 equality.
  1366 
  1367 * Some renaming of class constants due to canonical name prefixing in
  1368 the new 'class' package:
  1369 
  1370     HOL.abs ~> HOL.abs_class.abs
  1371     HOL.divide ~> HOL.divide_class.divide
  1372     0 ~> HOL.zero_class.zero
  1373     1 ~> HOL.one_class.one
  1374     op + ~> HOL.plus_class.plus
  1375     op - ~> HOL.minus_class.minus
  1376     uminus ~> HOL.minus_class.uminus
  1377     op * ~> HOL.times_class.times
  1378     op < ~> HOL.ord_class.less
  1379     op <= > HOL.ord_class.less_eq
  1380     Nat.power ~> Power.power_class.power
  1381     Nat.size ~> Nat.size_class.size
  1382     Numeral.number_of ~> Numeral.number_class.number_of
  1383     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1384     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1385     Orderings.min ~> Orderings.ord_class.min
  1386     Orderings.max ~> Orderings.ord_class.max
  1387     Divides.op div ~> Divides.div_class.div
  1388     Divides.op mod ~> Divides.div_class.mod
  1389     Divides.op dvd ~> Divides.div_class.dvd
  1390 
  1391 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1392 
  1393 a) User-defined constants using any of the names "plus", "minus",
  1394 "times", "less" or "less_eq". The standard syntax translations for
  1395 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1396 names.
  1397 
  1398 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1399 INCOMPATIBILITY: use more specific names.
  1400 
  1401 c) Permutative equations (e.g. "a + b = b + a")
  1402 Since the change of names also changes the order of terms, permutative
  1403 rewrite rules may get applied in a different order. Experience shows
  1404 that this is rarely the case (only two adaptions in the whole Isabelle
  1405 distribution).  INCOMPATIBILITY: rewrite proofs
  1406 
  1407 d) ML code directly refering to constant names
  1408 This in general only affects hand-written proof tactics, simprocs and
  1409 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1410 Consider using @{const_name} antiquotation.
  1411 
  1412 * New class "default" with associated constant "default".
  1413 
  1414 * Function "sgn" is now overloaded and available on int, real, complex
  1415 (and other numeric types), using class "sgn".  Two possible defs of
  1416 sgn are given as equational assumptions in the classes sgn_if and
  1417 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1418 INCOMPATIBILITY.
  1419 
  1420 * Locale "partial_order" now unified with class "order" (cf. theory
  1421 Orderings), added parameter "less".  INCOMPATIBILITY.
  1422 
  1423 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1424 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1425 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1426 
  1427 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1428 changed order of proof goals in instance proofs.
  1429 
  1430 * The transitivity reasoner for partial and linear orders is set up
  1431 for classes "order" and "linorder".  Instances of the reasoner are available
  1432 in all contexts importing or interpreting the corresponding locales.
  1433 Method "order" invokes the reasoner separately; the reasoner
  1434 is also integrated with the Simplifier as a solver.  Diagnostic
  1435 command 'print_orders' shows the available instances of the reasoner
  1436 in the current context.
  1437 
  1438 * Localized monotonicity predicate in theory "Orderings"; integrated
  1439 lemmas max_of_mono and min_of_mono with this predicate.
  1440 INCOMPATIBILITY.
  1441 
  1442 * Formulation of theorem "dense" changed slightly due to integration
  1443 with new class dense_linear_order.
  1444 
  1445 * Uniform lattice theory development in HOL.
  1446 
  1447     constants "meet" and "join" now named "inf" and "sup"
  1448     constant "Meet" now named "Inf"
  1449 
  1450     classes "meet_semilorder" and "join_semilorder" now named
  1451       "lower_semilattice" and "upper_semilattice"
  1452     class "lorder" now named "lattice"
  1453     class "comp_lat" now named "complete_lattice"
  1454 
  1455     Instantiation of lattice classes allows explicit definitions
  1456     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1457 
  1458   INCOMPATIBILITY.  Theorem renames:
  1459 
  1460     meet_left_le            ~> inf_le1
  1461     meet_right_le           ~> inf_le2
  1462     join_left_le            ~> sup_ge1
  1463     join_right_le           ~> sup_ge2
  1464     meet_join_le            ~> inf_sup_ord
  1465     le_meetI                ~> le_infI
  1466     join_leI                ~> le_supI
  1467     le_meet                 ~> le_inf_iff
  1468     le_join                 ~> ge_sup_conv
  1469     meet_idempotent         ~> inf_idem
  1470     join_idempotent         ~> sup_idem
  1471     meet_comm               ~> inf_commute
  1472     join_comm               ~> sup_commute
  1473     meet_leI1               ~> le_infI1
  1474     meet_leI2               ~> le_infI2
  1475     le_joinI1               ~> le_supI1
  1476     le_joinI2               ~> le_supI2
  1477     meet_assoc              ~> inf_assoc
  1478     join_assoc              ~> sup_assoc
  1479     meet_left_comm          ~> inf_left_commute
  1480     meet_left_idempotent    ~> inf_left_idem
  1481     join_left_comm          ~> sup_left_commute
  1482     join_left_idempotent    ~> sup_left_idem
  1483     meet_aci                ~> inf_aci
  1484     join_aci                ~> sup_aci
  1485     le_def_meet             ~> le_iff_inf
  1486     le_def_join             ~> le_iff_sup
  1487     join_absorp2            ~> sup_absorb2
  1488     join_absorp1            ~> sup_absorb1
  1489     meet_absorp1            ~> inf_absorb1
  1490     meet_absorp2            ~> inf_absorb2
  1491     meet_join_absorp        ~> inf_sup_absorb
  1492     join_meet_absorp        ~> sup_inf_absorb
  1493     distrib_join_le         ~> distrib_sup_le
  1494     distrib_meet_le         ~> distrib_inf_le
  1495 
  1496     add_meet_distrib_left   ~> add_inf_distrib_left
  1497     add_join_distrib_left   ~> add_sup_distrib_left
  1498     is_join_neg_meet        ~> is_join_neg_inf
  1499     is_meet_neg_join        ~> is_meet_neg_sup
  1500     add_meet_distrib_right  ~> add_inf_distrib_right
  1501     add_join_distrib_right  ~> add_sup_distrib_right
  1502     add_meet_join_distribs  ~> add_sup_inf_distribs
  1503     join_eq_neg_meet        ~> sup_eq_neg_inf
  1504     meet_eq_neg_join        ~> inf_eq_neg_sup
  1505     add_eq_meet_join        ~> add_eq_inf_sup
  1506     meet_0_imp_0            ~> inf_0_imp_0
  1507     join_0_imp_0            ~> sup_0_imp_0
  1508     meet_0_eq_0             ~> inf_0_eq_0
  1509     join_0_eq_0             ~> sup_0_eq_0
  1510     neg_meet_eq_join        ~> neg_inf_eq_sup
  1511     neg_join_eq_meet        ~> neg_sup_eq_inf
  1512     join_eq_if              ~> sup_eq_if
  1513 
  1514     mono_meet               ~> mono_inf
  1515     mono_join               ~> mono_sup
  1516     meet_bool_eq            ~> inf_bool_eq
  1517     join_bool_eq            ~> sup_bool_eq
  1518     meet_fun_eq             ~> inf_fun_eq
  1519     join_fun_eq             ~> sup_fun_eq
  1520     meet_set_eq             ~> inf_set_eq
  1521     join_set_eq             ~> sup_set_eq
  1522     meet1_iff               ~> inf1_iff
  1523     meet2_iff               ~> inf2_iff
  1524     meet1I                  ~> inf1I
  1525     meet2I                  ~> inf2I
  1526     meet1D1                 ~> inf1D1
  1527     meet2D1                 ~> inf2D1
  1528     meet1D2                 ~> inf1D2
  1529     meet2D2                 ~> inf2D2
  1530     meet1E                  ~> inf1E
  1531     meet2E                  ~> inf2E
  1532     join1_iff               ~> sup1_iff
  1533     join2_iff               ~> sup2_iff
  1534     join1I1                 ~> sup1I1
  1535     join2I1                 ~> sup2I1
  1536     join1I1                 ~> sup1I1
  1537     join2I2                 ~> sup1I2
  1538     join1CI                 ~> sup1CI
  1539     join2CI                 ~> sup2CI
  1540     join1E                  ~> sup1E
  1541     join2E                  ~> sup2E
  1542 
  1543     is_meet_Meet            ~> is_meet_Inf
  1544     Meet_bool_def           ~> Inf_bool_def
  1545     Meet_fun_def            ~> Inf_fun_def
  1546     Meet_greatest           ~> Inf_greatest
  1547     Meet_lower              ~> Inf_lower
  1548     Meet_set_def            ~> Inf_set_def
  1549 
  1550     Sup_def                 ~> Sup_Inf
  1551     Sup_bool_eq             ~> Sup_bool_def
  1552     Sup_fun_eq              ~> Sup_fun_def
  1553     Sup_set_eq              ~> Sup_set_def
  1554 
  1555     listsp_meetI            ~> listsp_infI
  1556     listsp_meet_eq          ~> listsp_inf_eq
  1557 
  1558     meet_min                ~> inf_min
  1559     join_max                ~> sup_max
  1560 
  1561 * Added syntactic class "size"; overloaded constant "size" now has
  1562 type "'a::size ==> bool"
  1563 
  1564 * Internal reorganisation of `size' of datatypes: size theorems
  1565 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1566 simplification rules by default!); theorems "prod.size" now named
  1567 "*.size".
  1568 
  1569 * Class "div" now inherits from class "times" rather than "type".
  1570 INCOMPATIBILITY.
  1571 
  1572 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1573 Linorder etc.  have disappeared; operations defined in terms of
  1574 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1575 
  1576 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1577 
  1578 * HOL-Word: New extensive library and type for generic, fixed size
  1579 machine words, with arithemtic, bit-wise, shifting and rotating
  1580 operations, reflection into int, nat, and bool lists, automation for
  1581 linear arithmetic (by automatic reflection into nat or int), including
  1582 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1583 arithmetic type classes, supporting automatic simplification of
  1584 numerals on all operations.
  1585 
  1586 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1587 
  1588 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1589 
  1590 * Code generator library theories:
  1591   - Code_Integer represents HOL integers by big integer literals in target
  1592     languages.
  1593   - Code_Char represents HOL characters by character literals in target
  1594     languages.
  1595   - Code_Char_chr like Code_Char, but also offers treatment of character
  1596     codes; includes Code_Integer.
  1597   - Executable_Set allows to generate code for finite sets using lists.
  1598   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1599     denominator).
  1600   - Executable_Real implements a subset of real numbers, namly those
  1601     representable by rational numbers.
  1602   - Efficient_Nat implements natural numbers by integers, which in general will
  1603     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1604     includes Code_Integer.
  1605   - Code_Index provides an additional datatype index which is mapped to
  1606     target-language built-in integers.
  1607   - Code_Message provides an additional datatype message_string which is isomorphic to
  1608     strings; messages are mapped to target-language strings.
  1609 
  1610 * New package for inductive predicates
  1611 
  1612   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1613 
  1614     inductive
  1615       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1616       for z_1 :: U_1 and ... and z_n :: U_m
  1617     where
  1618       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1619     | ...
  1620 
  1621   with full support for type-inference, rather than
  1622 
  1623     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1624 
  1625     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1626     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1627 
  1628     inductive "s z_1 ... z_m"
  1629     intros
  1630       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1631       ...
  1632 
  1633   For backward compatibility, there is a wrapper allowing inductive
  1634   sets to be defined with the new package via
  1635 
  1636     inductive_set
  1637       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1638       for z_1 :: U_1 and ... and z_n :: U_m
  1639     where
  1640       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1641     | ...
  1642 
  1643   or
  1644 
  1645     inductive_set
  1646       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1647       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1648       for z_1 :: U_1 and ... and z_n :: U_m
  1649     where
  1650       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1651     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1652     | ...
  1653 
  1654   if the additional syntax "p ..." is required.
  1655 
  1656   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1657   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1658 
  1659   INCOMPATIBILITIES:
  1660 
  1661   - Since declaration and definition of inductive sets or predicates
  1662     is no longer separated, abbreviations involving the newly
  1663     introduced sets or predicates must be specified together with the
  1664     introduction rules after the 'where' keyword (see above), rather
  1665     than before the actual inductive definition.
  1666 
  1667   - The variables in induction and elimination rules are now
  1668     quantified in the order of their occurrence in the introduction
  1669     rules, rather than in alphabetical order. Since this may break
  1670     some proofs, these proofs either have to be repaired, e.g. by
  1671     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1672     statements of the form
  1673 
  1674       case (rule_i a_i_1 ... a_i_{k_i})
  1675 
  1676     or the old order of quantification has to be restored by explicitly adding
  1677     meta-level quantifiers in the introduction rules, i.e.
  1678 
  1679       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1680 
  1681   - The format of the elimination rules is now
  1682 
  1683       p z_1 ... z_m x_1 ... x_n ==>
  1684         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1685         ==> ... ==> P
  1686 
  1687     for predicates and
  1688 
  1689       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1690         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1691         ==> ... ==> P
  1692 
  1693     for sets rather than
  1694 
  1695       x : s z_1 ... z_m ==>
  1696         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1697         ==> ... ==> P
  1698 
  1699     This may require terms in goals to be expanded to n-tuples
  1700     (e.g. using case_tac or simplification with the split_paired_all
  1701     rule) before the above elimination rule is applicable.
  1702 
  1703   - The elimination or case analysis rules for (mutually) inductive
  1704     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1705     list of rules "p_1_..._p_k.elims" is no longer available.
  1706 
  1707 * New package "function"/"fun" for general recursive functions,
  1708 supporting mutual and nested recursion, definitions in local contexts,
  1709 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1710 for small examples, and the separate tutorial on the function
  1711 package. The old recdef "package" is still available as before, but
  1712 users are encouraged to use the new package.
  1713 
  1714 * Method "lexicographic_order" automatically synthesizes termination
  1715 relations as lexicographic combinations of size measures. 
  1716 
  1717 * Case-expressions allow arbitrary constructor-patterns (including
  1718 "_") and take their order into account, like in functional
  1719 programming.  Internally, this is translated into nested
  1720 case-expressions; missing cases are added and mapped to the predefined
  1721 constant "undefined". In complicated cases printing may no longer show
  1722 the original input but the internal form. Lambda-abstractions allow
  1723 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1724 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1725 variable.
  1726 
  1727 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1728 is an abbreviation for "of_nat :: nat => int". The simplification
  1729 rules for "of_nat" have been changed to work like "int" did
  1730 previously.  Potential INCOMPATIBILITY:
  1731   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1732   - of_nat_diff and of_nat_mult are no longer default simp rules
  1733 
  1734 * Method "algebra" solves polynomial equations over (semi)rings using
  1735 Groebner bases. The (semi)ring structure is defined by locales and the
  1736 tool setup depends on that generic context. Installing the method for
  1737 a specific type involves instantiating the locale and possibly adding
  1738 declarations for computation on the coefficients.  The method is
  1739 already instantiated for natural numbers and for the axiomatic class
  1740 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1741 CALCULEMUS 2007 for the general principles underlying this
  1742 architecture of context-aware proof-tools.
  1743 
  1744 * Method "ferrack" implements quantifier elimination over
  1745 special-purpose dense linear orders using locales (analogous to
  1746 "algebra"). The method is already installed for class
  1747 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1748 rat, etc.
  1749 
  1750 * Former constant "List.op @" now named "List.append".  Use ML
  1751 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1752 circumvent possible incompatibilities when working on ML level.
  1753 
  1754 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1755 
  1756 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1757 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1758 
  1759 * New syntax for Haskell-like list comprehension (input only), eg.
  1760 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1761 
  1762 * The special syntax for function "filter" has changed from [x :
  1763 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1764 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1765 
  1766 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1767 defined on nat only, as an abbreviation for [a..<Suc b]
  1768 INCOMPATIBILITY.
  1769 
  1770 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1771 
  1772 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1773 
  1774 * New lemma collection field_simps (an extension of ring_simps) for
  1775 manipulating (in)equations involving division. Multiplies with all
  1776 denominators that can be proved to be non-zero (in equations) or
  1777 positive/negative (in inequations).
  1778 
  1779 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1780 have been improved and renamed to ring_simps, group_simps and
  1781 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1782 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1783 
  1784 * Theory Library/Commutative_Ring: switched from recdef to function
  1785 package; constants add, mul, pow now curried.  Infix syntax for
  1786 algebraic operations.
  1787 
  1788 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1789 INCOMPATIBILITY.
  1790 
  1791 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1792 INCOMPATIBILITY.
  1793 
  1794 * HOL/records: generalised field-update to take a function on the
  1795 field rather than the new value: r(|A := x|) is translated to A_update
  1796 (K x) r The K-combinator that is internally used is called K_record.
  1797 INCOMPATIBILITY: Usage of the plain update functions has to be
  1798 adapted.
  1799  
  1800 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1801 * x = 0, which are required for a semiring.  Richer structures do not
  1802 inherit from semiring_0 anymore, because this property is a theorem
  1803 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1804 there is more to prove, but this is mostly trivial.
  1805 
  1806 * Class "recpower" is generalized to arbitrary monoids, not just
  1807 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1808 commutativity or semiring properties additionally.
  1809 
  1810 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1811 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1812 better use 'abbreviation'.
  1813 
  1814 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1815 
  1816 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1817 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1818 significant changes for setting up numeral syntax for types:
  1819   - New constants Numeral.pred and Numeral.succ instead
  1820       of former Numeral.bin_pred and Numeral.bin_succ.
  1821   - Use integer operations instead of bin_add, bin_mult and so on.
  1822   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1823   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1824 
  1825 See src/HOL/Integ/IntArith.thy for an example setup.
  1826 
  1827 * Command 'normal_form' computes the normal form of a term that may
  1828 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1829 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1830 heavy-duty computations because the functions are compiled to ML
  1831 first.  Correspondingly, a method "normalization" is provided.  See
  1832 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1833 
  1834 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1835 25 like -->); output depends on the "iff" print_mode, the default is
  1836 "A = B" (with priority 50).
  1837 
  1838 * Relations less (<) and less_eq (<=) are also available on type bool.
  1839 Modified syntax to disallow nesting without explicit parentheses,
  1840 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1841 INCOMPATIBILITY.
  1842 
  1843 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1844 
  1845 * Relation composition operator "op O" now has precedence 75 and binds
  1846 stronger than union and intersection. INCOMPATIBILITY.
  1847 
  1848 * The old set interval syntax "{m..n(}" (and relatives) has been
  1849 removed.  Use "{m..<n}" (and relatives) instead.
  1850 
  1851 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1852 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1853 ``declare [[simproc del: neq]]''.
  1854 
  1855 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1856 True/False.
  1857 
  1858 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1859 
  1860 * Theorem setsum_mult renamed to setsum_right_distrib.
  1861 
  1862 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1863 ``rule'' method.
  1864 
  1865 * Reimplemented methods "sat" and "satx", with several improvements:
  1866 goals no longer need to be stated as "<prems> ==> False", equivalences
  1867 (i.e. "=" on type bool) are handled, variable names of the form
  1868 "lit_<n>" are no longer reserved, significant speedup.
  1869 
  1870 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1871 zChaff is still supported as well.
  1872 
  1873 * 'inductive' and 'datatype': provide projections of mutual rules,
  1874 bundled as foo_bar.inducts;
  1875 
  1876 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1877 Library.
  1878 
  1879 * Library: moved theory Accessible_Part to main HOL.
  1880 
  1881 * Library: added theory Coinductive_List of potentially infinite lists
  1882 as greatest fixed-point.
  1883 
  1884 * Library: added theory AssocList which implements (finite) maps as
  1885 association lists.
  1886 
  1887 * Method "evaluation" solves goals (i.e. a boolean expression)
  1888 efficiently by compiling it to ML.  The goal is "proved" (via an
  1889 oracle) if it evaluates to True.
  1890 
  1891 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1892 also when invoked by the simplifier.  This results in the Simplifier
  1893 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1894 Configuration option fast_arith_split_limit=0 recovers the old
  1895 behavior.
  1896 
  1897 * Support for hex (0x20) and binary (0b1001) numerals.
  1898 
  1899 * New method: reify eqs (t), where eqs are equations for an
  1900 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1901 parameter, computes a term s::'b and a list xs::'a list and proves the
  1902 theorem I xs s = t. This is also known as reification or quoting. The
  1903 resulting theorem is applied to the subgoal to substitute t with I xs
  1904 s.  If t is omitted, the subgoal itself is reified.
  1905 
  1906 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1907 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1908 where f is supposed to be a computable function (in the sense of code
  1909 generattion). The method uses reify to compute s and xs as above then
  1910 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1911 r and finally gets the theorem t = r, which is again applied to the
  1912 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1913 
  1914 * Reflection: Automatic reification now handels binding, an example is
  1915 available in src/HOL/ex/ReflectionEx.thy
  1916 
  1917 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1918 command 'statespace' that is similar to 'record', but introduces an
  1919 abstract specification based on the locale infrastructure instead of
  1920 HOL types.  This leads to extra flexibility in composing state spaces,
  1921 in particular multiple inheritance and renaming of components.
  1922 
  1923 
  1924 *** HOL-Complex ***
  1925 
  1926 * Hyperreal: Functions root and sqrt are now defined on negative real
  1927 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1928 Nonnegativity side conditions have been removed from many lemmas, so
  1929 that more subgoals may now be solved by simplification; potential
  1930 INCOMPATIBILITY.
  1931 
  1932 * Real: new type classes formalize real normed vector spaces and
  1933 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1934 and norm :: 'a => real.
  1935 
  1936 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1937 reals into other types. The overloaded constant Reals :: 'a set is now
  1938 defined as range of_real; potential INCOMPATIBILITY.
  1939 
  1940 * Real: proper support for ML code generation, including 'quickcheck'.
  1941 Reals are implemented as arbitrary precision rationals.
  1942 
  1943 * Hyperreal: Several constants that previously worked only for the
  1944 reals have been generalized, so they now work over arbitrary vector
  1945 spaces. Type annotations may need to be added in some cases; potential
  1946 INCOMPATIBILITY.
  1947 
  1948   Infinitesimal  :: ('a::real_normed_vector) star set
  1949   HFinite        :: ('a::real_normed_vector) star set
  1950   HInfinite      :: ('a::real_normed_vector) star set
  1951   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1952   monad          :: ('a::real_normed_vector) star => 'a star set
  1953   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1954   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1955   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1956   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1957   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1958   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1959   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1960   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1961   sgn            :: 'a::real_normed_vector => 'a
  1962   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1963 
  1964 * Complex: Some complex-specific constants are now abbreviations for
  1965 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1966 hnorm.  Other constants have been entirely removed in favor of the
  1967 polymorphic versions (INCOMPATIBILITY):
  1968 
  1969   approx        <-- capprox
  1970   HFinite       <-- CFinite
  1971   HInfinite     <-- CInfinite
  1972   Infinitesimal <-- CInfinitesimal
  1973   monad         <-- cmonad
  1974   galaxy        <-- cgalaxy
  1975   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1976   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1977   (ns)deriv     <-- (ns)cderiv
  1978 
  1979 
  1980 *** HOL-Algebra ***
  1981 
  1982 * Formalisation of ideals and the quotient construction over rings.
  1983 
  1984 * Order and lattice theory no longer based on records.
  1985 INCOMPATIBILITY.
  1986 
  1987 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1988 greatest_closed.  INCOMPATIBILITY.
  1989 
  1990 * Method algebra is now set up via an attribute.  For examples see
  1991 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1992 of algebraic structures.
  1993 
  1994 * Renamed theory CRing to Ring.
  1995 
  1996 
  1997 *** HOL-Nominal ***
  1998 
  1999 * Substantial, yet incomplete support for nominal datatypes (binding
  2000 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2001 src/HOL/Nominal/Examples.  Prospective users should consult
  2002 http://isabelle.in.tum.de/nominal/
  2003 
  2004 
  2005 *** ML ***
  2006 
  2007 * ML basics: just one true type int, which coincides with IntInf.int
  2008 (even on SML/NJ).
  2009 
  2010 * ML within Isar: antiquotations allow to embed statically-checked
  2011 formal entities in the source, referring to the context available at
  2012 compile-time.  For example:
  2013 
  2014 ML {* @{sort "{zero,one}"} *}
  2015 ML {* @{typ "'a => 'b"} *}
  2016 ML {* @{term "%x. x"} *}
  2017 ML {* @{prop "x == y"} *}
  2018 ML {* @{ctyp "'a => 'b"} *}
  2019 ML {* @{cterm "%x. x"} *}
  2020 ML {* @{cprop "x == y"} *}
  2021 ML {* @{thm asm_rl} *}
  2022 ML {* @{thms asm_rl} *}
  2023 ML {* @{type_name c} *}
  2024 ML {* @{type_syntax c} *}
  2025 ML {* @{const_name c} *}
  2026 ML {* @{const_syntax c} *}
  2027 ML {* @{context} *}
  2028 ML {* @{theory} *}
  2029 ML {* @{theory Pure} *}
  2030 ML {* @{theory_ref} *}
  2031 ML {* @{theory_ref Pure} *}
  2032 ML {* @{simpset} *}
  2033 ML {* @{claset} *}
  2034 ML {* @{clasimpset} *}
  2035 
  2036 The same works for sources being ``used'' within an Isar context.
  2037 
  2038 * ML in Isar: improved error reporting; extra verbosity with
  2039 ML_Context.trace enabled.
  2040 
  2041 * Pure/General/table.ML: the join operations now works via exceptions
  2042 DUP/SAME instead of type option. This is simpler in simple cases, and
  2043 admits slightly more efficient complex applications.
  2044 
  2045 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2046 use Context.generic instead of just theory.
  2047 
  2048 * Pure: datatype Context.generic joins theory/Proof.context and
  2049 provides some facilities for code that works in either kind of
  2050 context, notably GenericDataFun for uniform theory and proof data.
  2051 
  2052 * Pure: simplified internal attribute type, which is now always
  2053 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2054 local (Proof.context) attributes have been discontinued, while
  2055 minimizing code duplication. Thm.rule_attribute and
  2056 Thm.declaration_attribute build canonical attributes; see also structure
  2057 Context for further operations on Context.generic, notably
  2058 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2059 declarations and definitions.
  2060 
  2061 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2062 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2063 init only required for impure data. INCOMPATIBILITY: empty really need
  2064 to be empty (no dependencies on theory content!)
  2065 
  2066 * Pure/kernel: consts certification ignores sort constraints given in
  2067 signature declarations. (This information is not relevant to the
  2068 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2069 potential INCOMPATIBILITY.
  2070 
  2071 * Pure: axiomatic type classes are now purely definitional, with
  2072 explicit proofs of class axioms and super class relations performed
  2073 internally. See Pure/axclass.ML for the main internal interfaces --
  2074 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2075 AxClass.axiomatize_class/classrel/arity supersede
  2076 Sign.add_classes/classrel/arities.
  2077 
  2078 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2079 global/local versions on theory vs. Proof.context have been
  2080 discontinued; Attrib.syntax and Method.syntax have been adapted
  2081 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2082 attributes, methods, etc.
  2083 
  2084 * Pure: several functions of signature "... -> theory -> theory * ..."
  2085 have been reoriented to "... -> theory -> ... * theory" in order to
  2086 allow natural usage in combination with the ||>, ||>>, |-> and
  2087 fold_map combinators.
  2088 
  2089 * Pure: official theorem names (closed derivations) and additional
  2090 comments (tags) are now strictly separate.  Name hints -- which are
  2091 maintained as tags -- may be attached any time without affecting the
  2092 derivation.
  2093 
  2094 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2095 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2096 achieve the old behaviour.
  2097 
  2098 * Pure: the "Goal" constant is now called "prop", supporting a
  2099 slightly more general idea of ``protecting'' meta-level rule
  2100 statements.
  2101 
  2102 * Pure: Logic.(un)varify only works in a global context, which is now
  2103 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2104 Logic.legacy_(un)varify as temporary workaround.
  2105 
  2106 * Pure: structure Name provides scalable operations for generating
  2107 internal variable names, notably Name.variants etc.  This replaces
  2108 some popular functions from term.ML:
  2109 
  2110   Term.variant		->  Name.variant
  2111   Term.variantlist	->  Name.variant_list
  2112   Term.invent_names	->  Name.invent_list
  2113 
  2114 Note that low-level renaming rarely occurs in new code -- operations
  2115 from structure Variable are used instead (see below).
  2116 
  2117 * Pure: structure Variable provides fundamental operations for proper
  2118 treatment of fixed/schematic variables in a context.  For example,
  2119 Variable.import introduces fixes for schematics of given facts and
  2120 Variable.export reverses the effect (up to renaming) -- this replaces
  2121 various freeze_thaw operations.
  2122 
  2123 * Pure: structure Goal provides simple interfaces for
  2124 init/conclude/finish and tactical prove operations (replacing former
  2125 Tactic.prove).  Goal.prove is the canonical way to prove results
  2126 within a given context; Goal.prove_global is a degraded version for
  2127 theory level goals, including a global Drule.standard.  Note that
  2128 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2129 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2130 in a locale context).
  2131 
  2132 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2133 and type checking (Syntax.check_term etc.), with common combinations
  2134 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2135 which are considered legacy and await removal.
  2136 
  2137 * Pure/Syntax: generic interfaces for type unchecking
  2138 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2139 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2140 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2141 available for convenience, but refer to the very same operations using
  2142 a mere theory instead of a full context.
  2143 
  2144 * Isar: simplified treatment of user-level errors, using exception
  2145 ERROR of string uniformly.  Function error now merely raises ERROR,
  2146 without any side effect on output channels.  The Isar toplevel takes
  2147 care of proper display of ERROR exceptions.  ML code may use plain
  2148 handle/can/try; cat_error may be used to concatenate errors like this:
  2149 
  2150   ... handle ERROR msg => cat_error msg "..."
  2151 
  2152 Toplevel ML code (run directly or through the Isar toplevel) may be
  2153 embedded into the Isar toplevel with exception display/debug like
  2154 this:
  2155 
  2156   Isar.toplevel (fn () => ...)
  2157 
  2158 INCOMPATIBILITY, removed special transform_error facilities, removed
  2159 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2160 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2161 -- use plain ERROR instead.
  2162 
  2163 * Isar: theory setup now has type (theory -> theory), instead of a
  2164 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2165 
  2166 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2167 ProofContext.debug/verbose flags.
  2168 
  2169 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2170 theory before entering a proof state.  Transactions now always see a
  2171 quasi-functional intermediate checkpoint, both in interactive and
  2172 batch mode.
  2173 
  2174 * Isar: simplified interfaces for outer syntax.  Renamed
  2175 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2176 OuterSyntax.add_parsers -- this functionality is now included in
  2177 OuterSyntax.command etc.  INCOMPATIBILITY.
  2178 
  2179 * Simplifier: the simpset of a running simplification process now
  2180 contains a proof context (cf. Simplifier.the_context), which is the
  2181 very context that the initial simpset has been retrieved from (by
  2182 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2183 (solver, looper etc.) may depend on arbitrary proof data.
  2184 
  2185 * Simplifier.inherit_context inherits the proof context (plus the
  2186 local bounds) of the current simplification process; any simproc
  2187 etc. that calls the Simplifier recursively should do this!  Removed
  2188 former Simplifier.inherit_bounds, which is already included here --
  2189 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2190 specify an explicit context using Simplifier.context/theory_context.
  2191 
  2192 * Simplifier/Classical Reasoner: more abstract interfaces
  2193 change_simpset/claset for modifying the simpset/claset reference of a
  2194 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2195 INCOMPATIBILITY.
  2196 
  2197 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2198 "Trueprop" etc.
  2199 
  2200 
  2201 *** System ***
  2202 
  2203 * settings: the default heap location within ISABELLE_HOME_USER now
  2204 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2205 Isabelle installations.
  2206 
  2207 * isabelle-process: option -S (secure mode) disables some critical
  2208 operations, notably runtime compilation and evaluation of ML source
  2209 code.
  2210 
  2211 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2212 
  2213 * Support for parallel execution, using native multicore support of
  2214 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2215 independent theories, according to the given theory header
  2216 specifications. The maximum number of worker threads is specified via
  2217 usedir option -M or the "max-threads" setting in Proof General. A
  2218 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2219 to 6 on a 8-core machine.  User-code needs to observe certain
  2220 guidelines for thread-safe programming, see appendix A in the Isar
  2221 Implementation manual.
  2222 
  2223 
  2224 
  2225 New in Isabelle2005 (October 2005)
  2226 ----------------------------------
  2227 
  2228 *** General ***
  2229 
  2230 * Theory headers: the new header syntax for Isar theories is
  2231 
  2232   theory <name>
  2233   imports <theory1> ... <theoryN>
  2234   uses <file1> ... <fileM>
  2235   begin
  2236 
  2237 where the 'uses' part is optional.  The previous syntax
  2238 
  2239   theory <name> = <theory1> + ... + <theoryN>:
  2240 
  2241 will disappear in the next release.  Use isatool fixheaders to convert
  2242 existing theory files.  Note that there is no change in ancient
  2243 non-Isar theories now, but these will disappear soon.
  2244 
  2245 * Theory loader: parent theories can now also be referred to via
  2246 relative and absolute paths.
  2247 
  2248 * Command 'find_theorems' searches for a list of criteria instead of a
  2249 list of constants. Known criteria are: intro, elim, dest, name:string,
  2250 simp:term, and any term. Criteria can be preceded by '-' to select
  2251 theorems that do not match. Intro, elim, dest select theorems that
  2252 match the current goal, name:s selects theorems whose fully qualified
  2253 name contain s, and simp:term selects all simplification rules whose
  2254 lhs match term.  Any other term is interpreted as pattern and selects
  2255 all theorems matching the pattern. Available in ProofGeneral under
  2256 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2257 
  2258   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2259 
  2260 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2261 matching the current goal as introduction rule and not having "HOL."
  2262 in their name (i.e. not being defined in theory HOL).
  2263 
  2264 * Command 'thms_containing' has been discontinued in favour of
  2265 'find_theorems'; INCOMPATIBILITY.
  2266 
  2267 * Communication with Proof General is now 8bit clean, which means that
  2268 Unicode text in UTF-8 encoding may be used within theory texts (both
  2269 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2270 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2271 
  2272   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2273   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2274 
  2275 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2276 Classical Reasoner.  Typical big applications run around 2 times
  2277 faster.
  2278 
  2279 
  2280 *** Document preparation ***
  2281 
  2282 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2283 of raw sources.  Only those symbols that do not require additional
  2284 LaTeX packages (depending on comments in isabellesym.sty) are
  2285 displayed properly, everything else is left verbatim.  isatool display
  2286 and isatool print are used as front ends (these are subject to the
  2287 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2288 
  2289 * Command tags control specific markup of certain regions of text,
  2290 notably folding and hiding.  Predefined tags include "theory" (for
  2291 theory begin and end), "proof" for proof commands, and "ML" for
  2292 commands involving ML code; the additional tags "visible" and
  2293 "invisible" are unused by default.  Users may give explicit tag
  2294 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2295 interpretation of tags is determined by the LaTeX job during document
  2296 preparation: see option -V of isatool usedir, or options -n and -t of
  2297 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2298 \isadroptag.
  2299 
  2300 Several document versions may be produced at the same time via isatool
  2301 usedir (the generated index.html will link all of them).  Typical
  2302 specifications include ''-V document=theory,proof,ML'' to present
  2303 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2304 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2305 these parts without any formal replacement text.  The Isabelle site
  2306 default settings produce ''document'' and ''outline'' versions as
  2307 specified above.
  2308 
  2309 * Several new antiquotations:
  2310 
  2311   @{term_type term} prints a term with its type annotated;
  2312 
  2313   @{typeof term} prints the type of a term;
  2314 
  2315   @{const const} is the same as @{term const}, but checks that the
  2316   argument is a known logical constant;
  2317 
  2318   @{term_style style term} and @{thm_style style thm} print a term or
  2319   theorem applying a "style" to it
  2320 
  2321   @{ML text}
  2322 
  2323 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2324 definitions, equations, inequations etc., 'concl' printing only the
  2325 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2326 to print the specified premise.  TermStyle.add_style provides an ML
  2327 interface for introducing further styles.  See also the "LaTeX Sugar"
  2328 document practical applications.  The ML antiquotation prints
  2329 type-checked ML expressions verbatim.
  2330 
  2331 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2332 and 'text' support optional locale specification '(in loc)', which
  2333 specifies the default context for interpreting antiquotations.  For
  2334 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2335 
  2336 * Option 'locale=NAME' of antiquotations specifies an alternative
  2337 context interpreting the subsequent argument.  For example: @{thm
  2338 [locale=lattice] inf_assoc}.
  2339 
  2340 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2341 a proof context.
  2342 
  2343 * Proper output of antiquotations for theory commands involving a
  2344 proof context (such as 'locale' or 'theorem (in loc) ...').
  2345 
  2346 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2347 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2348 
  2349 * isatool usedir: new option -C (default true) controls whether option
  2350 -D should include a copy of the original document directory; -C false
  2351 prevents unwanted effects such as copying of administrative CVS data.
  2352 
  2353 
  2354 *** Pure ***
  2355 
  2356 * Considerably improved version of 'constdefs' command.  Now performs
  2357 automatic type-inference of declared constants; additional support for
  2358 local structure declarations (cf. locales and HOL records), see also
  2359 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2360 sequential dependencies of definitions within a single 'constdefs'
  2361 section; moreover, the declared name needs to be an identifier.  If
  2362 all fails, consider to fall back on 'consts' and 'defs' separately.
  2363 
  2364 * Improved indexed syntax and implicit structures.  First of all,
  2365 indexed syntax provides a notational device for subscripted
  2366 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2367 expressions.  Secondly, in a local context with structure
  2368 declarations, number indexes \<^sub>n or the empty index (default
  2369 number 1) refer to a certain fixed variable implicitly; option
  2370 show_structs controls printing of implicit structures.  Typical
  2371 applications of these concepts involve record types and locales.
  2372 
  2373 * New command 'no_syntax' removes grammar declarations (and
  2374 translations) resulting from the given syntax specification, which is
  2375 interpreted in the same manner as for the 'syntax' command.
  2376 
  2377 * 'Advanced' translation functions (parse_translation etc.) may depend
  2378 on the signature of the theory context being presently used for
  2379 parsing/printing, see also isar-ref manual.
  2380 
  2381 * Improved 'oracle' command provides a type-safe interface to turn an
  2382 ML expression of type theory -> T -> term into a primitive rule of
  2383 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2384 is already included here); see also FOL/ex/IffExample.thy;
  2385 INCOMPATIBILITY.
  2386 
  2387 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2388 before); "cI" is no longer bound, use "c.intro" instead.
  2389 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2390 axclasses vs. locales.
  2391 
  2392 * Improved internal renaming of symbolic identifiers -- attach primes
  2393 instead of base 26 numbers.
  2394 
  2395 * New flag show_question_marks controls printing of leading question
  2396 marks in schematic variable names.
  2397 
  2398 * In schematic variable names, *any* symbol following \<^isub> or
  2399 \<^isup> is now treated as part of the base name.  For example, the
  2400 following works without printing of awkward ".0" indexes:
  2401 
  2402   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2403     by simp
  2404 
  2405 * Inner syntax includes (*(*nested*) comments*).
  2406 
  2407 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2408 annotations as "(00...)".
  2409 
  2410 * Clear separation of logical types and nonterminals, where the latter
  2411 may only occur in 'syntax' specifications or type abbreviations.
  2412 Before that distinction was only partially implemented via type class
  2413 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2414 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2415 exotic syntax specifications may require further adaption
  2416 (e.g. Cube/Cube.thy).
  2417 
  2418 * Removed obsolete type class "logic", use the top sort {} instead.
  2419 Note that non-logical types should be declared as 'nonterminals'
  2420 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2421 specifications.
  2422 
  2423 * Attributes 'induct' and 'cases': type or set names may now be
  2424 locally fixed variables as well.
  2425 
  2426 * Simplifier: can now control the depth to which conditional rewriting
  2427 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2428 Limit.
  2429 
  2430 * Simplifier: simplification procedures may now take the current
  2431 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2432 interface), which is very useful for calling the Simplifier
  2433 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2434 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2435 low-level mk_simproc no longer applies Logic.varify internally, to
  2436 allow for use in a context of fixed variables.
  2437 
  2438 * thin_tac now works even if the assumption being deleted contains !!
  2439 or ==>.  More generally, erule now works even if the major premise of
  2440 the elimination rule contains !! or ==>.
  2441 
  2442 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2443 
  2444 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2445 from Pure, which contains all common declarations already.  Both
  2446 theories are defined via plain Isabelle/Isar .thy files.
  2447 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2448 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2449 use isatool fixcpure to adapt your theory and ML sources.
  2450 
  2451 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2452 selections of theorems in named facts via index ranges.
  2453 
  2454 * 'print_theorems': in theory mode, really print the difference
  2455 wrt. the last state (works for interactive theory development only),
  2456 in proof mode print all local facts (cf. 'print_facts');
  2457 
  2458 * 'hide': option '(open)' hides only base names.
  2459 
  2460 * More efficient treatment of intermediate checkpoints in interactive
  2461 theory development.
  2462 
  2463 * Code generator is now invoked via code_module (incremental code
  2464 generation) and code_library (modular code generation, ML structures
  2465 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2466 must be quoted when used as identifiers.
  2467 
  2468 * New 'value' command for reading, evaluating and printing terms using
  2469 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2470 quoted when used as identifier.
  2471 
  2472 
  2473 *** Locales ***
  2474 
  2475 * New commands for the interpretation of locale expressions in
  2476 theories (1), locales (2) and proof contexts (3).  These generate
  2477 proof obligations from the expression specification.  After the
  2478 obligations have been discharged, theorems of the expression are added
  2479 to the theory, target locale or proof context.  The synopsis of the
  2480 commands is a follows:
  2481 
  2482   (1) interpretation expr inst
  2483   (2) interpretation target < expr
  2484   (3) interpret expr inst
  2485 
  2486 Interpretation in theories and proof contexts require a parameter
  2487 instantiation of terms from the current context.  This is applied to
  2488 specifications and theorems of the interpreted expression.
  2489 Interpretation in locales only permits parameter renaming through the
  2490 locale expression.  Interpretation is smart in that interpretations
  2491 that are active already do not occur in proof obligations, neither are
  2492 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2493 inspect active interpretations of a particular locale.  For details,
  2494 see the Isar Reference manual.  Examples can be found in
  2495 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2496 
  2497 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2498 'interpret' instead.
  2499 
  2500 * New context element 'constrains' for adding type constraints to
  2501 parameters.
  2502 
  2503 * Context expressions: renaming of parameters with syntax
  2504 redeclaration.
  2505 
  2506 * Locale declaration: 'includes' disallowed.
  2507 
  2508 * Proper static binding of attribute syntax -- i.e. types / terms /
  2509 facts mentioned as arguments are always those of the locale definition
  2510 context, independently of the context of later invocations.  Moreover,
  2511 locale operations (renaming and type / term instantiation) are applied
  2512 to attribute arguments as expected.
  2513 
  2514 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2515 actual attributes; rare situations may require Attrib.attribute to
  2516 embed those attributes into Attrib.src that lack concrete syntax.
  2517 Attribute implementations need to cooperate properly with the static
  2518 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2519 Attrib.XXX_thm etc. already do the right thing without further
  2520 intervention.  Only unusual applications -- such as "where" or "of"
  2521 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2522 on the context and the facts involved -- may have to assign parsed
  2523 values to argument tokens explicitly.
  2524 
  2525 * Changed parameter management in theorem generation for long goal
  2526 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2527 theorem statement in rare situations.
  2528 
  2529 * Locale inspection command 'print_locale' omits notes elements.  Use
  2530 'print_locale!' to have them included in the output.
  2531 
  2532 
  2533 *** Provers ***
  2534 
  2535 * Provers/hypsubst.ML: improved version of the subst method, for
  2536 single-step rewriting: it now works in bound variable contexts. New is
  2537 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2538 rewrite a different subterm than the original subst method, which is
  2539 still available as 'simplesubst'.
  2540 
  2541 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2542 and quasi orders.
  2543 
  2544 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2545 reflexive-transitive closure of relations.
  2546 
  2547 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2548 limit (previously hard-coded with a value of 20) user-definable.
  2549 
  2550 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2551 is peformed already.  Object-logics merely need to finish their
  2552 initial simpset configuration as before.  INCOMPATIBILITY.
  2553 
  2554 
  2555 *** HOL ***
  2556 
  2557 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2558 
  2559   syntax (epsilon)
  2560     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2561 
  2562 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2563 and x-symbol; use option '-m epsilon' to get it actually printed.
  2564 Moreover, the mathematically important symbolic identifier \<epsilon>
  2565 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2566 
  2567 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2568 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2569 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2570 support corresponding Isar calculations.
  2571 
  2572 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2573 instead of ":".
  2574 
  2575 * theory SetInterval: changed the syntax for open intervals:
  2576 
  2577   Old       New
  2578   {..n(}    {..<n}
  2579   {)n..}    {n<..}
  2580   {m..n(}   {m..<n}
  2581   {)m..n}   {m<..n}
  2582   {)m..n(}  {m<..<n}
  2583 
  2584 The old syntax is still supported but will disappear in the next
  2585 release.  For conversion use the following Emacs search and replace
  2586 patterns (these are not perfect but work quite well):
  2587 
  2588   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2589   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2590 
  2591 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2592 equalities in commutative rings; method 'algebra' provides a generic
  2593 interface.
  2594 
  2595 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2596 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2597 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2598 be a tuple pattern.
  2599 
  2600 Some new syntax forms are available:
  2601 
  2602   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2603   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2604   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2605   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2606 
  2607 The latter form "\<Sum>x < k. e" used to be based on a separate
  2608 function "Summation", which has been discontinued.
  2609 
  2610 * theory Finite_Set: in structured induction proofs, the insert case
  2611 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2612 (insert F x)'.
  2613 
  2614 * The 'refute' command has been extended to support a much larger
  2615 fragment of HOL, including axiomatic type classes, constdefs and
  2616 typedefs, inductive datatypes and recursion.
  2617 
  2618 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2619 Requires zChaff with proof generation to be installed.  See
  2620 HOL/ex/SAT_Examples.thy for examples.
  2621 
  2622 * Datatype induction via method 'induct' now preserves the name of the
  2623 induction variable. For example, when proving P(xs::'a list) by
  2624 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2625 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2626 in unstructured proof scripts.
  2627 
  2628 * Reworked implementation of records.  Improved scalability for
  2629 records with many fields, avoiding performance problems for type
  2630 inference. Records are no longer composed of nested field types, but
  2631 of nested extension types. Therefore the record type only grows linear
  2632 in the number of extensions and not in the number of fields.  The
  2633 top-level (users) view on records is preserved.  Potential
  2634 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2635 old record representation. The type generated for a record is called
  2636 <record_name>_ext_type.
  2637 
  2638 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2639 proofs triggered by a record definition or a simproc (if
  2640 quick_and_dirty is enabled).  Definitions of large records can take
  2641 quite long.
  2642 
  2643 New simproc record_upd_simproc for simplification of multiple record
  2644 updates enabled by default.  Moreover, trivial updates are also
  2645 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2646 occasionally, since simplification is more powerful by default.
  2647 
  2648 * typedef: proper support for polymorphic sets, which contain extra
  2649 type-variables in the term.
  2650 
  2651 * Simplifier: automatically reasons about transitivity chains
  2652 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2653 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2654 old proofs break occasionally as simplification may now solve more
  2655 goals than previously.
  2656 
  2657 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2658 present.  Works for all partial orders (class "order"), in particular
  2659 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2660 just like y <= x.
  2661 
  2662 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2663 bound variable or a constant then the let is unfolded.  Otherwise
  2664 first a is simplified to b, and then f b is simplified to g. If
  2665 possible we abstract b from g arriving at "let x = b in h x",
  2666 otherwise we unfold the let and arrive at g.  The simproc can be
  2667 enabled/disabled by the reference use_let_simproc.  Potential
  2668 INCOMPATIBILITY since simplification is more powerful by default.
  2669 
  2670 * Classical reasoning: the meson method now accepts theorems as arguments.
  2671 
  2672 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2673 jobs to provide advice on the provability of subgoals.
  2674 
  2675 * Theory OrderedGroup and Ring_and_Field: various additions and
  2676 improvements to faciliate calculations involving equalities and
  2677 inequalities.
  2678 
  2679 The following theorems have been eliminated or modified
  2680 (INCOMPATIBILITY):
  2681 
  2682   abs_eq             now named abs_of_nonneg
  2683   abs_of_ge_0        now named abs_of_nonneg
  2684   abs_minus_eq       now named abs_of_nonpos
  2685   imp_abs_id         now named abs_of_nonneg
  2686   imp_abs_neg_id     now named abs_of_nonpos
  2687   mult_pos           now named mult_pos_pos
  2688   mult_pos_le        now named mult_nonneg_nonneg
  2689   mult_pos_neg_le    now named mult_nonneg_nonpos
  2690   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2691   mult_neg           now named mult_neg_neg
  2692   mult_neg_le        now named mult_nonpos_nonpos
  2693 
  2694 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2695      
  2696      zero_le_square
  2697      not_square_less_zero 
  2698 
  2699   The following lemmas have been deleted from Real/RealPow:
  2700   
  2701      realpow_zero_zero
  2702      realpow_two
  2703      realpow_less
  2704      zero_le_power
  2705      realpow_two_le
  2706      abs_realpow_two
  2707      realpow_two_abs     
  2708 
  2709 * Theory Parity: added rules for simplifying exponents.
  2710 
  2711 * Theory List:
  2712 
  2713 The following theorems have been eliminated or modified
  2714 (INCOMPATIBILITY):
  2715 
  2716   list_all_Nil       now named list_all.simps(1)
  2717   list_all_Cons      now named list_all.simps(2)
  2718   list_all_conv      now named list_all_iff
  2719   set_mem_eq         now named mem_iff
  2720 
  2721 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2722 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2723 
  2724 
  2725 *** HOL-Complex ***
  2726 
  2727 * Theory RealDef: better support for embedding natural numbers and
  2728 integers in the reals.
  2729 
  2730 The following theorems have been eliminated or modified
  2731 (INCOMPATIBILITY):
  2732 
  2733   exp_ge_add_one_self  now requires no hypotheses
  2734   real_of_int_add      reversed direction of equality (use [symmetric])
  2735   real_of_int_minus    reversed direction of equality (use [symmetric])
  2736   real_of_int_diff     reversed direction of equality (use [symmetric])
  2737   real_of_int_mult     reversed direction of equality (use [symmetric])
  2738 
  2739 * Theory RComplete: expanded support for floor and ceiling functions.
  2740 
  2741 * Theory Ln is new, with properties of the natural logarithm
  2742 
  2743 * Hyperreal: There is a new type constructor "star" for making
  2744 nonstandard types.  The old type names are now type synonyms:
  2745 
  2746   hypreal = real star
  2747   hypnat = nat star
  2748   hcomplex = complex star
  2749 
  2750 * Hyperreal: Many groups of similarly-defined constants have been
  2751 replaced by polymorphic versions (INCOMPATIBILITY):
  2752 
  2753   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2754 
  2755   starset      <-- starsetNat, starsetC
  2756   *s*          <-- *sNat*, *sc*
  2757   starset_n    <-- starsetNat_n, starsetC_n
  2758   *sn*         <-- *sNatn*, *scn*
  2759   InternalSets <-- InternalNatSets, InternalCSets
  2760 
  2761   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2762   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2763   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2764   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2765   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2766 
  2767 * Hyperreal: Many type-specific theorems have been removed in favor of
  2768 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2769 
  2770   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2771   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2772   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2773   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2774   right_minus <-- hypreal_add_minus
  2775   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2776   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2777   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2778   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2779   mult_1_right <-- hcomplex_mult_one_right
  2780   mult_zero_left <-- hcomplex_mult_zero_left
  2781   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2782   right_distrib <-- hypnat_add_mult_distrib2
  2783   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2784   right_inverse <-- hypreal_mult_inverse
  2785   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2786   order_refl <-- {hypreal,hypnat}_le_refl
  2787   order_trans <-- {hypreal,hypnat}_le_trans
  2788   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2789   order_less_le <-- {hypreal,hypnat}_less_le
  2790   linorder_linear <-- {hypreal,hypnat}_le_linear
  2791   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2792   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2793   add_nonneg_nonneg <-- hypreal_le_add_order
  2794 
  2795 * Hyperreal: Separate theorems having to do with type-specific
  2796 versions of constants have been merged into theorems that apply to the
  2797 new polymorphic constants (INCOMPATIBILITY):
  2798 
  2799   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2800   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2801   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2802   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2803   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2804   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2805   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2806   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2807   STAR_diff <-- {STAR,STARC}_diff
  2808   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2809     STARC_hcomplex_of_complex}_image_subset
  2810   starset_n_Un <-- starset{Nat,C}_n_Un
  2811   starset_n_Int <-- starset{Nat,C}_n_Int
  2812   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2813   starset_n_diff <-- starset{Nat,C}_n_diff
  2814   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2815   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2816   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2817   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2818   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2819   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2820   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2821   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2822   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2823   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2824   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2825   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2826   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2827   starfun_diff <-- starfun{C,RC,CR}_diff
  2828   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2829   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2830   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2831   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2832   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2833   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2834   starfun_Id <-- starfunC_Id
  2835   starfun_approx <-- starfun{Nat,CR}_approx
  2836   starfun_capprox <-- starfun{C,RC}_capprox
  2837   starfun_abs <-- starfunNat_rabs
  2838   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2839   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2840   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2841   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2842   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2843   starfun_add_approx <-- starfunCR_add_approx
  2844   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2845   starfun_divide <-- starfun{C,CR,RC}_divide
  2846   starfun_n <-- starfun{Nat,C}_n
  2847   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2848   starfun_n_add <-- starfun{Nat,C}_n_add
  2849   starfun_n_add_minus <-- starfunNat_n_add_minus
  2850   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2851   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2852   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2853 
  2854   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2855   star_n_minus <-- {hypreal,hcomplex}_minus
  2856   star_n_diff <-- {hypreal,hcomplex}_diff
  2857   star_n_mult <-- {hypreal,hcomplex}_mult
  2858   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2859   star_n_le <-- {hypreal,hypnat}_le
  2860   star_n_less <-- {hypreal,hypnat}_less
  2861   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2862   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2863   star_n_abs <-- hypreal_hrabs
  2864   star_n_divide <-- hcomplex_divide
  2865 
  2866   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2867   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2868   star_of_diff <-- hypreal_of_real_diff
  2869   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2870   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2871   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2872   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2873   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2874   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2875   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2876   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2877   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2878   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2879   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2880   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2881   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2882   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2883   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2884   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2885   star_of_power <-- hypreal_of_real_power
  2886   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2887 
  2888 * Hyperreal: new method "transfer" that implements the transfer
  2889 principle of nonstandard analysis. With a subgoal that mentions
  2890 nonstandard types like "'a star", the command "apply transfer"
  2891 replaces it with an equivalent one that mentions only standard types.
  2892 To be successful, all free variables must have standard types; non-
  2893 standard variables must have explicit universal quantifiers.
  2894 
  2895 * Hyperreal: A theory of Taylor series.
  2896 
  2897 
  2898 *** HOLCF ***
  2899 
  2900 * Discontinued special version of 'constdefs' (which used to support
  2901 continuous functions) in favor of the general Pure one with full
  2902 type-inference.
  2903 
  2904 * New simplification procedure for solving continuity conditions; it
  2905 is much faster on terms with many nested lambda abstractions (cubic
  2906 instead of exponential time).
  2907 
  2908 * New syntax for domain package: selector names are now optional.
  2909 Parentheses should be omitted unless argument is lazy, for example:
  2910 
  2911   domain 'a stream = cons "'a" (lazy "'a stream")
  2912 
  2913 * New command 'fixrec' for defining recursive functions with pattern
  2914 matching; defining multiple functions with mutual recursion is also
  2915 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2916 sinr, or any data constructor defined by the domain package. The given
  2917 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2918 syntax and examples.
  2919 
  2920 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2921 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2922 but the proof obligation additionally includes an admissibility
  2923 requirement. The packages generate instances of class cpo or pcpo,
  2924 with continuity and strictness theorems for Rep and Abs.
  2925 
  2926 * HOLCF: Many theorems have been renamed according to a more standard naming
  2927 scheme (INCOMPATIBILITY):
  2928 
  2929   foo_inject:  "foo$x = foo$y ==> x = y"
  2930   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2931   foo_less:    "(foo$x << foo$y) = (x << y)"
  2932   foo_strict:  "foo$UU = UU"
  2933   foo_defined: "... ==> foo$x ~= UU"
  2934   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2935 
  2936 
  2937 *** ZF ***
  2938 
  2939 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2940 including the First Isomorphism Theorem (on quotienting by the kernel
  2941 of a homomorphism).
  2942 
  2943 * ZF/Simplifier: install second copy of type solver that actually
  2944 makes use of TC rules declared to Isar proof contexts (or locales);
  2945 the old version is still required for ML proof scripts.
  2946 
  2947 
  2948 *** Cube ***
  2949 
  2950 * Converted to Isar theory format; use locales instead of axiomatic
  2951 theories.
  2952 
  2953 
  2954 *** ML ***
  2955 
  2956 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2957 for ||>, ||>>, |>>,
  2958 
  2959 * Pure/library.ML no longer defines its own option datatype, but uses
  2960 that of the SML basis, which has constructors NONE and SOME instead of
  2961 None and Some, as well as exception Option.Option instead of OPTION.
  2962 The functions the, if_none, is_some, is_none have been adapted
  2963 accordingly, while Option.map replaces apsome.
  2964 
  2965 * Pure/library.ML: the exception LIST has been given up in favour of
  2966 the standard exceptions Empty and Subscript, as well as
  2967 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2968 superceded by the standard hd and tl functions etc.
  2969 
  2970 A number of basic list functions are no longer exported to the ML
  2971 toplevel, as they are variants of predefined functions.  The following
  2972 suggests how one can translate existing code:
  2973 
  2974     rev_append xs ys = List.revAppend (xs, ys)
  2975     nth_elem (i, xs) = List.nth (xs, i)
  2976     last_elem xs = List.last xs
  2977     flat xss = List.concat xss
  2978     seq fs = List.app fs
  2979     partition P xs = List.partition P xs
  2980     mapfilter f xs = List.mapPartial f xs
  2981 
  2982 * Pure/library.ML: several combinators for linear functional
  2983 transformations, notably reverse application and composition:
  2984 
  2985   x |> f                f #> g
  2986   (x, y) |-> f          f #-> g
  2987 
  2988 * Pure/library.ML: introduced/changed precedence of infix operators:
  2989 
  2990   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2991   infix 2 ?;
  2992   infix 3 o oo ooo oooo;
  2993   infix 4 ~~ upto downto;
  2994 
  2995 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2996 infix operators.
  2997 
  2998 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2999 fold_map support linear functional transformations and nesting.  For
  3000 example:
  3001 
  3002   fold f [x1, ..., xN] y =
  3003     y |> f x1 |> ... |> f xN
  3004 
  3005   (fold o fold) f [xs1, ..., xsN] y =
  3006     y |> fold f xs1 |> ... |> fold f xsN
  3007 
  3008   fold f [x1, ..., xN] =
  3009     f x1 #> ... #> f xN
  3010 
  3011   (fold o fold) f [xs1, ..., xsN] =
  3012     fold f xs1 #> ... #> fold f xsN
  3013 
  3014 * Pure/library.ML: the following selectors on type 'a option are
  3015 available:
  3016 
  3017   the:               'a option -> 'a  (*partial*)
  3018   these:             'a option -> 'a  where 'a = 'b list
  3019   the_default: 'a -> 'a option -> 'a
  3020   the_list:          'a option -> 'a list
  3021 
  3022 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3023 basic operations for association lists, following natural argument
  3024 order; moreover the explicit equality predicate passed here avoids
  3025 potentially expensive polymorphic runtime equality checks.
  3026 The old functions may be expressed as follows:
  3027 
  3028   assoc = uncurry (AList.lookup (op =))
  3029   assocs = these oo AList.lookup (op =)
  3030   overwrite = uncurry (AList.update (op =)) o swap
  3031 
  3032 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3033 
  3034   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3035   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3036 
  3037 replacing make_keylist and keyfilter (occassionally used)
  3038 Naive rewrites:
  3039 
  3040   make_keylist = AList.make
  3041   keyfilter = AList.find (op =)
  3042 
  3043 * eq_fst and eq_snd now take explicit equality parameter, thus
  3044   avoiding eqtypes. Naive rewrites:
  3045 
  3046     eq_fst = eq_fst (op =)
  3047     eq_snd = eq_snd (op =)
  3048 
  3049 * Removed deprecated apl and apr (rarely used).
  3050   Naive rewrites:
  3051 
  3052     apl (n, op) =>>= curry op n
  3053     apr (op, m) =>>= fn n => op (n, m)
  3054 
  3055 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3056 provides a reasonably efficient light-weight implementation of sets as
  3057 lists.
  3058 
  3059 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3060 few new operations; existing lookup and update are now curried to
  3061 follow natural argument order (for use with fold etc.);
  3062 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3063 
  3064 * Pure/General: output via the Isabelle channels of
  3065 writeln/warning/error etc. is now passed through Output.output, with a
  3066 hook for arbitrary transformations depending on the print_mode
  3067 (cf. Output.add_mode -- the first active mode that provides a output
  3068 function wins).  Already formatted output may be embedded into further
  3069 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3070 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3071 accommodate easy composition of diagnostic messages etc.  Programmers
  3072 rarely need to care about Output.output or Output.raw at all, with
  3073 some notable exceptions: Output.output is required when bypassing the
  3074 standard channels (writeln etc.), or in token translations to produce
  3075 properly formatted results; Output.raw is required when capturing
  3076 already output material that will eventually be presented to the user
  3077 a second time.  For the default print mode, both Output.output and
  3078 Output.raw have no effect.
  3079 
  3080 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3081 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3082 cumulative results are displayed at the end of a batch session.
  3083 
  3084 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3085 replaced by File.platform_path and File.shell_path (with appropriate
  3086 hooks).  This provides a clean interface for unusual systems where the
  3087 internal and external process view of file names are different.
  3088 
  3089 * Pure: more efficient orders for basic syntactic entities: added
  3090 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3091 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3092 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3093 orders now -- potential INCOMPATIBILITY for code that depends on a
  3094 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3095 Library.sort_strings on result).
  3096 
  3097 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3098 fold_types traverse types/terms from left to right, observing natural
  3099 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3100 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3101 
  3102 * Pure: name spaces have been refined, with significant changes of the
  3103 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3104 to extern(_table).  The plain name entry path is superceded by a
  3105 general 'naming' context, which also includes the 'policy' to produce
  3106 a fully qualified name and external accesses of a fully qualified
  3107 name; NameSpace.extend is superceded by context dependent
  3108 Sign.declare_name.  Several theory and proof context operations modify
  3109 the naming context.  Especially note Theory.restore_naming and
  3110 ProofContext.restore_naming to get back to a sane state; note that
  3111 Theory.add_path is no longer sufficient to recover from
  3112 Theory.absolute_path in particular.
  3113 
  3114 * Pure: new flags short_names (default false) and unique_names
  3115 (default true) for controlling output of qualified names.  If
  3116 short_names is set, names are printed unqualified.  If unique_names is
  3117 reset, the name prefix is reduced to the minimum required to achieve
  3118 the original result when interning again, even if there is an overlap
  3119 with earlier declarations.
  3120 
  3121 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3122 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3123 (useful for printing error messages).  INCOMPATIBILITY.
  3124 
  3125 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3126 Theory.theory are now identified, referring to the universal
  3127 Context.theory (see Pure/context.ML).  Actual signature and theory
  3128 content is managed as theory data.  The old code and interfaces were
  3129 spread over many files and structures; the new arrangement introduces
  3130 considerable INCOMPATIBILITY to gain more clarity:
  3131 
  3132   Context -- theory management operations (name, identity, inclusion,
  3133     parents, ancestors, merge, etc.), plus generic theory data;
  3134 
  3135   Sign -- logical signature and syntax operations (declaring consts,
  3136     types, etc.), plus certify/read for common entities;
  3137 
  3138   Theory -- logical theory operations (stating axioms, definitions,
  3139     oracles), plus a copy of logical signature operations (consts,
  3140     types, etc.); also a few basic management operations (Theory.copy,
  3141     Theory.merge, etc.)
  3142 
  3143 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3144 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3145 for convenience -- they merely return the theory.
  3146 
  3147 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3148 
  3149 * Pure: the Isar proof context type is already defined early in Pure
  3150 as Context.proof (note that ProofContext.context and Proof.context are
  3151 aliases, where the latter is the preferred name).  This enables other
  3152 Isabelle components to refer to that type even before Isar is present.
  3153 
  3154 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3155 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3156 any of these kinds.  For example, Sign.intern typeK is now
  3157 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3158 Theory.hide_types.  Also note that former
  3159 Theory.hide_classes/types/consts are now
  3160 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3161 internalize their arguments!  INCOMPATIBILITY.
  3162 
  3163 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3164 datatype thmref (with constructors Name and NameSelection) instead of
  3165 plain string -- INCOMPATIBILITY;
  3166 
  3167 * Pure: cases produced by proof methods specify options, where NONE
  3168 means to remove case bindings -- INCOMPATIBILITY in
  3169 (RAW_)METHOD_CASES.
  3170 
  3171 * Pure: the following operations retrieve axioms or theorems from a
  3172 theory node or theory hierarchy, respectively:
  3173 
  3174   Theory.axioms_of: theory -> (string * term) list
  3175   Theory.all_axioms_of: theory -> (string * term) list
  3176   PureThy.thms_of: theory -> (string * thm) list
  3177   PureThy.all_thms_of: theory -> (string * thm) list
  3178 
  3179 * Pure: print_tac now outputs the goal through the trace channel.
  3180 
  3181 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3182 Reference Toplevel.debug (default false) controls detailed printing
  3183 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3184 controls execution profiling -- set to 1 for time and 2 for space
  3185 (both increase the runtime).
  3186 
  3187 * Isar session: The initial use of ROOT.ML is now always timed,
  3188 i.e. the log will show the actual process times, in contrast to the
  3189 elapsed wall-clock time that the outer shell wrapper produces.
  3190 
  3191 * Simplifier: improved handling of bound variables (nameless
  3192 representation, avoid allocating new strings).  Simprocs that invoke
  3193 the Simplifier recursively should use Simplifier.inherit_bounds to
  3194 avoid local name clashes.  Failure to do so produces warnings
  3195 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3196 for further details.
  3197 
  3198 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3199 bindings for all theorems stored within a given theory; this may help
  3200 in porting non-Isar theories to Isar ones, while keeping ML proof
  3201 scripts for the time being.
  3202 
  3203 * ML operator HTML.with_charset specifies the charset begin used for
  3204 generated HTML files.  For example:
  3205 
  3206   HTML.with_charset "utf-8" use_thy "Hebrew";
  3207   HTML.with_charset "utf-8" use_thy "Chinese";
  3208 
  3209 
  3210 *** System ***
  3211 
  3212 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3213 isabelle, isatool etc.).
  3214 
  3215 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3216 isatool doc, isatool mkdir, display_drafts etc.).
  3217 
  3218 * isatool usedir: option -f allows specification of the ML file to be
  3219 used by Isabelle; default is ROOT.ML.
  3220 
  3221 * New isatool version outputs the version identifier of the Isabelle
  3222 distribution being used.
  3223 
  3224 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3225 (containing Boolean satisfiability problems) into Isabelle/HOL
  3226 theories.
  3227 
  3228 
  3229 
  3230 New in Isabelle2004 (April 2004)
  3231 --------------------------------
  3232 
  3233 *** General ***
  3234 
  3235 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3236   Replaces linorder.ML.
  3237 
  3238 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3239   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3240   (\<a>...\<z>), are now considered normal letters, and can therefore
  3241   be used anywhere where an ASCII letter (a...zA...Z) has until
  3242   now. COMPATIBILITY: This obviously changes the parsing of some
  3243   terms, especially where a symbol has been used as a binder, say
  3244   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3245   as an identifier.  Fix it by inserting a space around former
  3246   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3247   existing theory and ML files.
  3248 
  3249 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3250 
  3251 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3252   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3253   a normal (but invisible) letter. For multiple letter subscripts repeat
  3254   \<^isub> like this: x\<^isub>1\<^isub>2.
  3255 
  3256 * Pure: There are now sub-/superscripts that can span more than one
  3257   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3258   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3259   superscript. The new control characters are not identifier parts.
  3260 
  3261 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3262   content of "..." to the latex file instead of \isacntrl... . The "..."
  3263   may consist of any printable characters excluding the end bracket >.
  3264 
  3265 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3266   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3267   declare constants "final", which prevents their being given a definition
  3268   later.  It is useful for constants whose behaviour is fixed axiomatically
  3269   rather than definitionally, such as the meta-logic connectives.
  3270 
  3271 * Pure: 'instance' now handles general arities with general sorts
  3272   (i.e. intersections of classes),
  3273 
  3274 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3275   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3276   It can be changed to alter the colors/layout of generated pages.
  3277 
  3278 
  3279 *** Isar ***
  3280 
  3281 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3282   cut_tac, subgoal_tac and thin_tac:
  3283   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3284     locales are no longer forced to write Isar proof scripts.
  3285     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3286     emulations.
  3287   - INCOMPATIBILITY: names of variables to be instantiated may no
  3288     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3289     This is consistent with the instantiation attribute "where".
  3290 
  3291 * Attributes "where" and "of":
  3292   - Now take type variables of instantiated theorem into account when reading
  3293     the instantiation string.  This fixes a bug that caused instantiated
  3294     theorems to have too special types in some circumstances.
  3295   - "where" permits explicit instantiations of type variables.
  3296 
  3297 * Calculation commands "moreover" and "also" no longer interfere with
  3298   current facts ("this"), admitting arbitrary combinations with "then"
  3299   and derived forms.
  3300 
  3301 * Locales:
  3302   - Goal statements involving the context element "includes" no longer
  3303     generate theorems with internal delta predicates (those ending on
  3304     "_axioms") in the premise.
  3305     Resolve particular premise with <locale>.intro to obtain old form.
  3306   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3307     specification and "includes" elements in goal statement.
  3308   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3309     [intro?] and [elim?] (respectively) by default.
  3310   - Experimental command for instantiation of locales in proof contexts:
  3311         instantiate <label>[<attrs>]: <loc>
  3312     Instantiates locale <loc> and adds all its theorems to the current context
  3313     taking into account their attributes.  Label and attrs are optional
  3314     modifiers, like in theorem declarations.  If present, names of
  3315     instantiated theorems are qualified with <label>, and the attributes
  3316     <attrs> are applied after any attributes these theorems might have already.
  3317       If the locale has assumptions, a chained fact of the form
  3318     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3319     are derived.  The command does not support old-style locales declared
  3320     with "locale (open)".
  3321       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3322 
  3323 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3324   (Isar) contexts.
  3325 
  3326 
  3327 *** HOL ***
  3328 
  3329 * Proof import: new image HOL4 contains the imported library from
  3330   the HOL4 system with about 2500 theorems. It is imported by
  3331   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3332   can be used like any other Isabelle image.  See
  3333   HOL/Import/HOL/README for more information.
  3334 
  3335 * Simplifier:
  3336   - Much improved handling of linear and partial orders.
  3337     Reasoners for linear and partial orders are set up for type classes
  3338     "linorder" and "order" respectively, and are added to the default simpset
  3339     as solvers.  This means that the simplifier can build transitivity chains
  3340     to solve goals from the assumptions.
  3341   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3342     of blast or auto after simplification become unnecessary because the goal
  3343     is solved by simplification already.
  3344 
  3345 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3346     all proved in axiomatic type classes for semirings, rings and fields.
  3347 
  3348 * Numerics:
  3349   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3350     now formalized using the Ring_and_Field theory mentioned above.
  3351   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3352     than before, because now they are set up once in a generic manner.
  3353   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3354     Look for the general versions in Ring_and_Field (and Power if they concern
  3355     exponentiation).
  3356 
  3357 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3358 
  3359 * Records:
  3360   - Record types are now by default printed with their type abbreviation
  3361     instead of the list of all field types. This can be configured via
  3362     the reference "print_record_type_abbr".
  3363   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3364     (not enabled by default).
  3365   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3366     EX x. x = sel r to True (not enabled by default).
  3367   - Tactic "record_split_simp_tac" to split and simplify records added.
  3368 
  3369 * 'specification' command added, allowing for definition by
  3370   specification.  There is also an 'ax_specification' command that
  3371   introduces the new constants axiomatically.
  3372 
  3373 * arith(_tac) is now able to generate counterexamples for reals as well.
  3374 
  3375 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3376 
  3377 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3378   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3379 
  3380 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3381   matrix theory to linear programming.
  3382 
  3383 * Unions and Intersections:
  3384   The latex output syntax of UN and INT has been changed
  3385   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3386   i.e. the index formulae has become a subscript.
  3387   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3388 
  3389 * Unions and Intersections over Intervals:
  3390   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3391   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3392   like in normal math, and corresponding versions for < and for intersection.
  3393 
  3394 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3395   lexicographic dictonary ordering has been added as "lexord".
  3396 
  3397 * ML: the legacy theory structures Int and List have been removed. They had
  3398   conflicted with ML Basis Library structures having the same names.
  3399 
  3400 * 'refute' command added to search for (finite) countermodels.  Only works
  3401   for a fragment of HOL.  The installation of an external SAT solver is
  3402   highly recommended.  See "HOL/Refute.thy" for details.
  3403 
  3404 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3405   formulae under an assignment of free variables to random values.
  3406   In contrast to 'refute', it can deal with inductive datatypes,
  3407   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3408   for examples.
  3409 
  3410 
  3411 *** HOLCF ***
  3412 
  3413 * Streams now come with concatenation and are part of the HOLCF image
  3414 
  3415 
  3416 
  3417 New in Isabelle2003 (May 2003)
  3418 ------------------------------
  3419 
  3420 *** General ***
  3421 
  3422 * Provers/simplifier:
  3423 
  3424   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3425     Assumptions are now subject to complete mutual simplification,
  3426     not just from left to right. The simplifier now preserves
  3427     the order of assumptions.
  3428 
  3429     Potential INCOMPATIBILITY:
  3430 
  3431     -- simp sometimes diverges where the old version did
  3432        not, e.g. invoking simp on the goal
  3433 
  3434         [| P (f x); y = x; f x = f y |] ==> Q
  3435 
  3436        now gives rise to the infinite reduction sequence
  3437 
  3438         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3439 
  3440        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3441        kind of problem.
  3442 
  3443     -- Tactics combining classical reasoner and simplification (such as auto)
  3444        are also affected by this change, because many of them rely on
  3445        simp. They may sometimes diverge as well or yield a different numbers
  3446        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3447        in case of problems. Sometimes subsequent calls to the classical
  3448        reasoner will fail because a preceeding call to the simplifier too
  3449        eagerly simplified the goal, e.g. deleted redundant premises.
  3450 
  3451   - The simplifier trace now shows the names of the applied rewrite rules
  3452 
  3453   - You can limit the number of recursive invocations of the simplifier
  3454     during conditional rewriting (where the simplifie tries to solve the
  3455     conditions before applying the rewrite rule):
  3456     ML "simp_depth_limit := n"
  3457     where n is an integer. Thus you can force termination where previously
  3458     the simplifier would diverge.
  3459 
  3460   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3461 
  3462   - No longer aborts on failed congruence proof.  Instead, the
  3463     congruence is ignored.
  3464 
  3465 * Pure: New generic framework for extracting programs from constructive
  3466   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3467   as HOL/Extraction for some case studies.
  3468 
  3469 * Pure: The main goal of the proof state is no longer shown by default, only
  3470 the subgoals. This behaviour is controlled by a new flag.
  3471    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3472 (ML: Proof.show_main_goal).
  3473 
  3474 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3475 rules whose conclusion matches subgoal 1:
  3476       PG menu: Isabelle/Isar -> Show me -> matching rules
  3477 The rules are ordered by how closely they match the subgoal.
  3478 In particular, rules that solve a subgoal outright are displayed first
  3479 (or rather last, the way they are printed).
  3480 (ML: ProofGeneral.print_intros())
  3481 
  3482 * Pure: New flag trace_unify_fail causes unification to print
  3483 diagnostic information (PG: in trace buffer) when it fails. This is
  3484 useful for figuring out why single step proofs like rule, erule or
  3485 assumption failed.
  3486 
  3487 * Pure: Locale specifications now produce predicate definitions
  3488 according to the body of text (covering assumptions modulo local
  3489 definitions); predicate "loc_axioms" covers newly introduced text,
  3490 while "loc" is cumulative wrt. all included locale expressions; the
  3491 latter view is presented only on export into the global theory
  3492 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3493 on the old view without predicates;
  3494 
  3495 * Pure: predefined locales "var" and "struct" are useful for sharing
  3496 parameters (as in CASL, for example); just specify something like
  3497 ``var x + var y + struct M'' as import;
  3498 
  3499 * Pure: improved thms_containing: proper indexing of facts instead of
  3500 raw theorems; check validity of results wrt. current name space;
  3501 include local facts of proof configuration (also covers active
  3502 locales), cover fixed variables in index; may use "_" in term
  3503 specification; an optional limit for the number of printed facts may
  3504 be given (the default is 40);
  3505 
  3506 * Pure: disallow duplicate fact bindings within new-style theory files
  3507 (batch-mode only);
  3508 
  3509 * Provers: improved induct method: assumptions introduced by case
  3510 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3511 the goal statement); "foo" still refers to all facts collectively;
  3512 
  3513 * Provers: the function blast.overloaded has been removed: all constants
  3514 are regarded as potentially overloaded, which improves robustness in exchange
  3515 for slight decrease in efficiency;
  3516 
  3517 * Provers/linorder: New generic prover for transitivity reasoning over
  3518 linear orders.  Note: this prover is not efficient!
  3519 
  3520 * Isar: preview of problems to finish 'show' now produce an error
  3521 rather than just a warning (in interactive mode);
  3522 
  3523 
  3524 *** HOL ***
  3525 
  3526 * arith(_tac)
  3527 
  3528  - Produces a counter example if it cannot prove a goal.
  3529    Note that the counter example may be spurious if the goal is not a formula
  3530    of quantifier-free linear arithmetic.
  3531    In ProofGeneral the counter example appears in the trace buffer.
  3532 
  3533  - Knows about div k and mod k where k is a numeral of type nat or int.
  3534 
  3535  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3536    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3537    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3538 
  3539 * simp's arithmetic capabilities have been enhanced a bit: it now
  3540 takes ~= in premises into account (by performing a case split);
  3541 
  3542 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3543 are distributed over a sum of terms;
  3544 
  3545 * New tactic "trans_tac" and method "trans" instantiate
  3546 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3547 "<=", "<" and "=").
  3548 
  3549 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3550 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3551 
  3552 * 'typedef' command has new option "open" to suppress the set
  3553 definition;
  3554 
  3555 * functions Min and Max on finite sets have been introduced (theory
  3556 Finite_Set);
  3557 
  3558 * attribute [symmetric] now works for relations as well; it turns
  3559 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3560 
  3561 * induct over a !!-quantified statement (say !!x1..xn):
  3562   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3563 
  3564 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3565 %x. None. Warning: empty_def now refers to the previously hidden definition
  3566 of the empty set.
  3567 
  3568 * Algebra: formalization of classical algebra.  Intended as base for
  3569 any algebraic development in Isabelle.  Currently covers group theory
  3570 (up to Sylow's theorem) and ring theory (Universal Property of
  3571 Univariate Polynomials).  Contributions welcome;
  3572 
  3573 * GroupTheory: deleted, since its material has been moved to Algebra;
  3574 
  3575 * Complex: new directory of the complex numbers with numeric constants,
  3576 nonstandard complex numbers, and some complex analysis, standard and
  3577 nonstandard (Jacques Fleuriot);
  3578 
  3579 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3580 
  3581 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3582 Fleuriot);
  3583 
  3584 * Real/HahnBanach: updated and adapted to locales;
  3585 
  3586 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3587 Gray and Kramer);
  3588 
  3589 * UNITY: added the Meier-Sanders theory of progress sets;
  3590 
  3591 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3592 as abstract algorithms, instantiated to the JVM;
  3593 
  3594 * Bali: Java source language formalization. Type system, operational
  3595 semantics, axiomatic semantics. Supported language features:
  3596 classes, interfaces, objects,virtual methods, static methods,
  3597 static/instance fields, arrays, access modifiers, definite
  3598 assignment, exceptions.
  3599 
  3600 
  3601 *** ZF ***
  3602 
  3603 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3604 universe, etc.);
  3605 
  3606 * Main ZF: virtually all theories converted to new-style format;
  3607 
  3608 
  3609 *** ML ***
  3610 
  3611 * Pure: Tactic.prove provides sane interface for internal proofs;
  3612 omits the infamous "standard" operation, so this is more appropriate
  3613 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3614 
  3615 * Pure: improved error reporting of simprocs;
  3616 
  3617 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3618 up simprocs;
  3619 
  3620 
  3621 *** Document preparation ***
  3622 
  3623 * uses \par instead of \\ for line breaks in theory text. This may
  3624 shift some page breaks in large documents. To get the old behaviour
  3625 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3626 
  3627 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3628 other packages
  3629 
  3630 * \<euro> now needs package babel/greek instead of marvosym (which
  3631 broke \Rightarrow)
  3632 
  3633 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3634 textcomp package)
  3635 
  3636 
  3637 
  3638 New in Isabelle2002 (March 2002)
  3639 --------------------------------
  3640 
  3641 *** Document preparation ***
  3642 
  3643 * greatly simplified document preparation setup, including more
  3644 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3645 instructive isatool mkdir; users should basically be able to get
  3646 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3647 users may run a separate document processing stage manually like this:
  3648 "isatool usedir -D output HOL Test && isatool document Test/output";
  3649 
  3650 * theory dependency graph may now be incorporated into documents;
  3651 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3652 with \includegraphics of LaTeX;
  3653 
  3654 * proper spacing of consecutive markup elements, especially text
  3655 blocks after section headings;
  3656 
  3657 * support bold style (for single symbols only), input syntax is like
  3658 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3659 
  3660 * \<bullet> is now output as bold \cdot by default, which looks much
  3661 better in printed text;
  3662 
  3663 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3664 note that these symbols are currently unavailable in Proof General /
  3665 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3666 
  3667 * isatool latex no longer depends on changed TEXINPUTS, instead
  3668 isatool document copies the Isabelle style files to the target
  3669 location;
  3670 
  3671 
  3672 *** Isar ***
  3673 
  3674 * Pure/Provers: improved proof by cases and induction;
  3675   - 'case' command admits impromptu naming of parameters (such as
  3676     "case (Suc n)");
  3677   - 'induct' method divinates rule instantiation from the inductive
  3678     claim; no longer requires excessive ?P bindings for proper
  3679     instantiation of cases;
  3680   - 'induct' method properly enumerates all possibilities of set/type
  3681     rules; as a consequence facts may be also passed through *type*
  3682     rules without further ado;
  3683   - 'induct' method now derives symbolic cases from the *rulified*
  3684     rule (before it used to rulify cases stemming from the internal
  3685     atomized version); this means that the context of a non-atomic
  3686     statement becomes is included in the hypothesis, avoiding the
  3687     slightly cumbersome show "PROP ?case" form;
  3688   - 'induct' may now use elim-style induction rules without chaining
  3689     facts, using ``missing'' premises from the goal state; this allows
  3690     rules stemming from inductive sets to be applied in unstructured
  3691     scripts, while still benefitting from proper handling of non-atomic
  3692     statements; NB: major inductive premises need to be put first, all
  3693     the rest of the goal is passed through the induction;
  3694   - 'induct' proper support for mutual induction involving non-atomic
  3695     rule statements (uses the new concept of simultaneous goals, see
  3696     below);
  3697   - append all possible rule selections, but only use the first
  3698     success (no backtracking);
  3699   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3700   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3701   - added 'print_induct_rules' (covered by help item in recent Proof
  3702     General versions);
  3703   - moved induct/cases attributes to Pure, methods to Provers;
  3704   - generic method setup instantiated for FOL and HOL;
  3705 
  3706 * Pure: support multiple simultaneous goal statements, for example
  3707 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3708 meta-level mechanism, this acts as if several individual goals had
  3709 been stated separately; in particular common proof methods need to be
  3710 repeated in order to cover all claims; note that a single elimination
  3711 step is *not* sufficient to establish the two conjunctions, so this
  3712 fails:
  3713 
  3714   assume "A & B" then have A and B ..   (*".." fails*)
  3715 
  3716 better use "obtain" in situations as above; alternative refer to
  3717 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3718 
  3719 * Pure: proper integration with ``locales''; unlike the original
  3720 version by Florian Kammller, Isar locales package high-level proof
  3721 contexts rather than raw logical ones (e.g. we admit to include
  3722 attributes everywhere); operations on locales include merge and
  3723 rename; support for implicit arguments (``structures''); simultaneous
  3724 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3725 some examples;
  3726 
  3727 * Pure: the following commands have been ``localized'', supporting a
  3728 target locale specification "(in name)": 'lemma', 'theorem',
  3729 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3730 stored both within the locale and at the theory level (exported and
  3731 qualified by the locale name);
  3732 
  3733 * Pure: theory goals may now be specified in ``long'' form, with
  3734 ad-hoc contexts consisting of arbitrary locale elements. for example
  3735 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3736 definitions may be given, too); the result is a meta-level rule with
  3737 the context elements being discharged in the obvious way;
  3738 
  3739 * Pure: new proof command 'using' allows to augment currently used
  3740 facts after a goal statement ('using' is syntactically analogous to
  3741 'apply', but acts on the goal's facts only); this allows chained facts
  3742 to be separated into parts given before and after a claim, as in
  3743 ``from a and b have C using d and e <proof>'';
  3744 
  3745 * Pure: renamed "antecedent" case to "rule_context";
  3746 
  3747 * Pure: new 'judgment' command records explicit information about the
  3748 object-logic embedding (used by several tools internally); no longer
  3749 use hard-wired "Trueprop";
  3750 
  3751 * Pure: added 'corollary' command;
  3752 
  3753 * Pure: fixed 'token_translation' command;
  3754 
  3755 * Pure: removed obsolete 'exported' attribute;
  3756 
  3757 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3758 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3759 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3760 
  3761 * Pure: method 'atomize' presents local goal premises as object-level
  3762 statements (atomic meta-level propositions); setup controlled via
  3763 rewrite rules declarations of 'atomize' attribute; example
  3764 application: 'induct' method with proper rule statements in improper
  3765 proof *scripts*;
  3766 
  3767 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3768 now consider the syntactic context of assumptions, giving a better
  3769 chance to get type-inference of the arguments right (this is
  3770 especially important for locales);
  3771 
  3772 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3773 mode;
  3774 
  3775 * Pure/obtain: the formal conclusion "thesis", being marked as
  3776 ``internal'', may no longer be reference directly in the text;
  3777 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3778 situations;
  3779 
  3780 * Pure: generic 'sym' attribute which declares a rule both as pure
  3781 'elim?' and for the 'symmetric' operation;
  3782 
  3783 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3784 text; the fixed correlation with particular command syntax has been
  3785 discontinued;
  3786 
  3787 * Pure: new method 'rules' is particularly well-suited for proof
  3788 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3789 but often produces more compact proof terms with less detours;
  3790 
  3791 * Pure/Provers/classical: simplified integration with pure rule
  3792 attributes and methods; the classical "intro?/elim?/dest?"
  3793 declarations coincide with the pure ones; the "rule" method no longer
  3794 includes classically swapped intros; "intro" and "elim" methods no
  3795 longer pick rules from the context; also got rid of ML declarations
  3796 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3797 INCOMPATIBILITY;
  3798 
  3799 * Provers/classical: attribute 'swapped' produces classical inversions
  3800 of introduction rules;
  3801 
  3802 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3803 rules instead of full simplifier context; 'iff' attribute handles
  3804 conditional rules;
  3805 
  3806 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3807 
  3808 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3809 "(permissive)" option to recover old behavior;
  3810 
  3811 * HOL: 'inductive' no longer features separate (collective) attributes
  3812 for 'intros' (was found too confusing);
  3813 
  3814 * HOL: properly declared induction rules less_induct and
  3815 wf_induct_rule;
  3816 
  3817 
  3818 *** HOL ***
  3819 
  3820 * HOL: moved over to sane numeral syntax; the new policy is as
  3821 follows:
  3822 
  3823   - 0 and 1 are polymorphic constants, which are defined on any
  3824   numeric type (nat, int, real etc.);
  3825 
  3826   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3827   binary representation internally;
  3828 
  3829   - type nat has special constructor Suc, and generally prefers Suc 0
  3830   over 1::nat and Suc (Suc 0) over 2::nat;
  3831 
  3832 This change may cause significant problems of INCOMPATIBILITY; here
  3833 are some hints on converting existing sources:
  3834 
  3835   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3836   entities, so expressions involving "-" (unary or binary minus) need
  3837   to be spaced properly;
  3838 
  3839   - existing occurrences of "1" may need to be constraint "1::nat" or
  3840   even replaced by Suc 0; similar for old "2";
  3841 
  3842   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3843 
  3844   - remove all special provisions on numerals in proofs;
  3845 
  3846 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3847 representation (depends on bin_arith_simps in the default context);
  3848 
  3849 * HOL: symbolic syntax for x^2 (numeral 2);
  3850 
  3851 * HOL: the class of all HOL types is now called "type" rather than
  3852 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3853 in axclass/classes, instance/arities, and (usually rare) occurrences
  3854 in typings (of consts etc.); internally the class is called
  3855 "HOL.type", ML programs should refer to HOLogic.typeS;
  3856 
  3857 * HOL/record package improvements:
  3858   - new derived operations "fields" to build a partial record section,
  3859     "extend" to promote a fixed record to a record scheme, and
  3860     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3861     declared as simp by default;
  3862   - shared operations ("more", "fields", etc.) now need to be always
  3863     qualified) --- potential INCOMPATIBILITY;
  3864   - removed "make_scheme" operations (use "make" with "extend") --
  3865     INCOMPATIBILITY;
  3866   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3867   - provides cases/induct rules for use with corresponding Isar
  3868     methods (for concrete records, record schemes, concrete more
  3869     parts, and schematic more parts -- in that order);
  3870   - internal definitions directly based on a light-weight abstract
  3871     theory of product types over typedef rather than datatype;
  3872 
  3873 * HOL: generic code generator for generating executable ML code from
  3874 specifications; specific support for HOL constructs such as inductive
  3875 datatypes and sets, as well as recursive functions; can be invoked
  3876 via 'generate_code' theory section;
  3877 
  3878 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3879 
  3880 * HOL: consolidated and renamed several theories.  In particular:
  3881         Ord.thy has been absorbed into HOL.thy
  3882         String.thy has been absorbed into List.thy
  3883 
  3884 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3885 (beware of argument permutation!);
  3886 
  3887 * HOL: linorder_less_split superseded by linorder_cases;
  3888 
  3889 * HOL/List: "nodups" renamed to "distinct";
  3890 
  3891 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3892 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3893   - Ex_def has changed, now need to use some_eq_ex
  3894 
  3895 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3896 in this (rare) case use:
  3897 
  3898   delSWrapper "split_all_tac"
  3899   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3900 
  3901 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3902 MAY FAIL;
  3903 
  3904 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3905 Isabelle's type classes, ^ on functions and relations has too general
  3906 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3907 necessary to attach explicit type constraints;
  3908 
  3909 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3910 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3911 renamed accordingly (eg "compI" -> "rel_compI").
  3912 
  3913 * HOL: syntax translations now work properly with numerals and records
  3914 expressions;
  3915 
  3916 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3917 of "lam" -- INCOMPATIBILITY;
  3918 
  3919 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3920 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3921 renamed "Product_Type.unit";
  3922 
  3923 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3924 
  3925 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3926 the "cases" method);
  3927 
  3928 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3929 Florian Kammller);
  3930 
  3931 * HOL/IMP: updated and converted to new-style theory format; several
  3932 parts turned into readable document, with proper Isar proof texts and
  3933 some explanations (by Gerwin Klein);
  3934 
  3935 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3936 
  3937 * HOL-Hyperreal is now a logic image;
  3938 
  3939 
  3940 *** HOLCF ***
  3941 
  3942 * Isar: consts/constdefs supports mixfix syntax for continuous
  3943 operations;
  3944 
  3945 * Isar: domain package adapted to new-style theory format, e.g. see
  3946 HOLCF/ex/Dnat.thy;
  3947 
  3948 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3949 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3950 lift.induct_tac, always use UU instead of Undef;
  3951 
  3952 * HOLCF/IMP: updated and converted to new-style theory;
  3953 
  3954 
  3955 *** ZF ***
  3956 
  3957 * Isar: proper integration of logic-specific tools and packages,
  3958 including theory commands '(co)inductive', '(co)datatype',
  3959 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3960 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3961 
  3962 * theory Main no longer includes AC; for the Axiom of Choice, base
  3963 your theory on Main_ZFC;
  3964 
  3965 * the integer library now covers quotients and remainders, with many
  3966 laws relating division to addition, multiplication, etc.;
  3967 
  3968 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3969 typeless version of the formalism;
  3970 
  3971 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3972 format;
  3973 
  3974 * ZF/Induct: new directory for examples of inductive definitions,
  3975 including theory Multiset for multiset orderings; converted to
  3976 new-style theory format;
  3977 
  3978 * ZF: many new theorems about lists, ordinals, etc.;
  3979 
  3980 
  3981 *** General ***
  3982 
  3983 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3984 variable proof controls level of detail: 0 = no proofs (only oracle
  3985 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3986 also ref manual for further ML interfaces;
  3987 
  3988 * Pure/axclass: removed obsolete ML interface
  3989 goal_subclass/goal_arity;
  3990 
  3991 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3992 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3993 separate tokens, so expressions involving minus need to be spaced
  3994 properly;
  3995 
  3996 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3997 rather than "infixl" or "infixr";
  3998 
  3999 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4000 sort constraint specifications in type inference; e.g. "x::_::foo"
  4001 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4002 type variable);
  4003 
  4004 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4005 control output of nested => (types); the default behavior is
  4006 "type_brackets";
  4007 
  4008 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4009 tokens into AST constants;
  4010 
  4011 * Pure/syntax: prefer later declarations of translations and print
  4012 translation functions; potential INCOMPATIBILITY: need to reverse
  4013 multiple declarations for same syntax element constant;
  4014 
  4015 * Pure/show_hyps reset by default (in accordance to existing Isar
  4016 practice);
  4017 
  4018 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4019 addSafter;
  4020 
  4021 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4022 as well;
  4023 
  4024 * system: tested support for MacOS X; should be able to get Isabelle +
  4025 Proof General to work in a plain Terminal after installing Poly/ML
  4026 (e.g. from the Isabelle distribution area) and GNU bash alone
  4027 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4028 support requires further installations, e.g. from
  4029 http://fink.sourceforge.net/);
  4030 
  4031 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4032 
  4033 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4034 of 40 MB), cf. ML_OPTIONS;
  4035 
  4036 * system: Proof General keywords specification is now part of the
  4037 Isabelle distribution (see etc/isar-keywords.el);
  4038 
  4039 * system: support for persistent Proof General sessions (refrain from
  4040 outdating all loaded theories on startup); user may create writable
  4041 logic images like this: ``isabelle -q HOL Test'';
  4042 
  4043 * system: smart selection of Isabelle process versus Isabelle
  4044 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4045 run both "isabelle" and "Isabelle" even if file names are badly
  4046 damaged (executable inspects the case of the first letter of its own
  4047 name); added separate "isabelle-process" and "isabelle-interface";
  4048 
  4049 * system: refrain from any attempt at filtering input streams; no
  4050 longer support ``8bit'' encoding of old isabelle font, instead proper
  4051 iso-latin characters may now be used; the related isatools
  4052 "symbolinput" and "nonascii" have disappeared as well;
  4053 
  4054 * system: removed old "xterm" interface (the print modes "xterm" and
  4055 "xterm_color" are still available for direct use in a suitable
  4056 terminal);
  4057 
  4058 
  4059 
  4060 New in Isabelle99-2 (February 2001)
  4061 -----------------------------------
  4062 
  4063 *** Overview of INCOMPATIBILITIES ***
  4064 
  4065 * HOL: please note that theories in the Library and elsewhere often use the
  4066 new-style (Isar) format; to refer to their theorems in an ML script you must
  4067 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4068 
  4069 * HOL: inductive package no longer splits induction rule aggressively,
  4070 but only as far as specified by the introductions given; the old
  4071 format may be recovered via ML function complete_split_rule or attribute
  4072 'split_rule (complete)';
  4073 
  4074 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4075 gfp_Tarski to gfp_unfold;
  4076 
  4077 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4078 
  4079 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4080 relation); infix "^^" has been renamed "``"; infix "``" has been
  4081 renamed "`"; "univalent" has been renamed "single_valued";
  4082 
  4083 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4084 operation;
  4085 
  4086 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4087 
  4088 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4089 
  4090 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4091 consequence, it is no longer monotonic wrt. the local goal context
  4092 (which is now passed through the inductive cases);
  4093 
  4094 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4095 \<gg> to \<ggreater>;
  4096 
  4097 
  4098 *** Document preparation ***
  4099 
  4100 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4101 available: are "it" for near math-mode best-style output, "sl" for
  4102 slanted text style, and "tt" for plain type-writer; if no
  4103 \isabellestyle command is given, output is according to slanted
  4104 type-writer);
  4105 
  4106 * support sub/super scripts (for single symbols only), input syntax is
  4107 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4108 
  4109 * some more standard symbols; see Appendix A of the system manual for
  4110 the complete list of symbols defined in isabellesym.sty;
  4111 
  4112 * improved isabelle style files; more abstract symbol implementation
  4113 (should now use \isamath{...} and \isatext{...} in custom symbol
  4114 definitions);
  4115 
  4116 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4117 state; Note that presentation of goal states does not conform to
  4118 actual human-readable proof documents.  Please do not include goal
  4119 states into document output unless you really know what you are doing!
  4120 
  4121 * proper indentation of antiquoted output with proportional LaTeX
  4122 fonts;
  4123 
  4124 * no_document ML operator temporarily disables LaTeX document
  4125 generation;
  4126 
  4127 * isatool unsymbolize tunes sources for plain ASCII communication;
  4128 
  4129 
  4130 *** Isar ***
  4131 
  4132 * Pure: Isar now suffers initial goal statements to contain unbound
  4133 schematic variables (this does not conform to actual readable proof
  4134 documents, due to unpredictable outcome and non-compositional proof
  4135 checking); users who know what they are doing may use schematic goals
  4136 for Prolog-style synthesis of proven results;
  4137 
  4138 * Pure: assumption method (an implicit finishing) now handles actual
  4139 rules as well;
  4140 
  4141 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4142 initial goal, declare "that" only as Pure intro (only for single
  4143 steps); the "that" rule assumption may now be involved in implicit
  4144 finishing, thus ".." becomes a feasible for trivial obtains;
  4145 
  4146 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4147 instance proofs may be performed by "..";
  4148 
  4149 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4150 statements as well;
  4151 
  4152 * Pure: more robust selection of calculational rules;
  4153 
  4154 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4155 rule (as well as the assumption rule);
  4156 
  4157 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4158 lemmas, using the graph browser tool;
  4159 
  4160 * Pure: predict failure of "show" in interactive mode;
  4161 
  4162 * Pure: 'thms_containing' now takes actual terms as arguments;
  4163 
  4164 * HOL: improved method 'induct' --- now handles non-atomic goals
  4165 (potential INCOMPATIBILITY); tuned error handling;
  4166 
  4167 * HOL: cases and induct rules now provide explicit hints about the
  4168 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4169 any remaining facts are inserted into the goal verbatim;
  4170 
  4171 * HOL: local contexts (aka cases) may now contain term bindings as
  4172 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4173 the result to be shown in each case;
  4174 
  4175 * HOL: added 'recdef_tc' command;
  4176 
  4177 * isatool convert assists in eliminating legacy ML scripts;
  4178 
  4179 
  4180 *** HOL ***
  4181 
  4182 * HOL/Library: a collection of generic theories to be used together
  4183 with main HOL; the theory loader path already includes this directory
  4184 by default; the following existing theories have been moved here:
  4185 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4186 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4187 
  4188 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4189 modelling and verification task performed in Isabelle/HOL +
  4190 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4191 
  4192 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4193 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4194 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4195 'domain', this makes the theory consistent with mathematical
  4196 literature;
  4197 
  4198 * HOL basics: added overloaded operations "inverse" and "divide"
  4199 (infix "/"), syntax for generic "abs" operation, generic summation
  4200 operator \<Sum>;
  4201 
  4202 * HOL/typedef: simplified package, provide more useful rules (see also
  4203 HOL/subset.thy);
  4204 
  4205 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4206 now expressed as a proper nested rule (old-style tactic scripts may
  4207 require atomize_strip_tac to cope with non-atomic premises);
  4208 
  4209 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4210 to "split_conv" (old name still available for compatibility);
  4211 
  4212 * HOL: improved concrete syntax for strings (e.g. allows translation
  4213 rules with string literals);
  4214 
  4215 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4216  and Fleuriot's mechanization of analysis, including the transcendental
  4217  functions for the reals;
  4218 
  4219 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4220 
  4221 
  4222 *** CTT ***
  4223 
  4224 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4225 "lam" is displayed as TWO lambda-symbols
  4226 
  4227 * CTT: theory Main now available, containing everything (that is, Bool
  4228 and Arith);
  4229 
  4230 
  4231 *** General ***
  4232 
  4233 * Pure: the Simplifier has been implemented properly as a derived rule
  4234 outside of the actual kernel (at last!); the overall performance
  4235 penalty in practical applications is about 50%, while reliability of
  4236 the Isabelle inference kernel has been greatly improved;
  4237 
  4238 * print modes "brackets" and "no_brackets" control output of nested =>
  4239 (types) and ==> (props); the default behaviour is "brackets";
  4240 
  4241 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4242 as assumptions as well;
  4243 
  4244 * system: support Poly/ML 4.0;
  4245 
  4246 * system: isatool install handles KDE version 1 or 2;
  4247 
  4248 
  4249 
  4250 New in Isabelle99-1 (October 2000)
  4251 ----------------------------------
  4252 
  4253 *** Overview of INCOMPATIBILITIES ***
  4254 
  4255 * HOL: simplification of natural numbers is much changed; to partly
  4256 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4257 issue the following ML commands:
  4258 
  4259   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4260   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4261 
  4262 * HOL: simplification no longer dives into case-expressions; this is
  4263 controlled by "t.weak_case_cong" for each datatype t;
  4264 
  4265 * HOL: nat_less_induct renamed to less_induct;
  4266 
  4267 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4268 fixsome to patch .thy and .ML sources automatically;
  4269 
  4270   select_equality  -> some_equality
  4271   select_eq_Ex     -> some_eq_ex
  4272   selectI2EX       -> someI2_ex
  4273   selectI2         -> someI2
  4274   selectI          -> someI
  4275   select1_equality -> some1_equality
  4276   Eps_sym_eq       -> some_sym_eq_trivial
  4277   Eps_eq           -> some_eq_trivial
  4278 
  4279 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4280 
  4281 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4282 instead);
  4283 
  4284 * HOL: the recursion equations generated by 'recdef' are now called
  4285 f.simps instead of f.rules;
  4286 
  4287 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4288 
  4289 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4290 sometimes be needed;
  4291 
  4292 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4293 
  4294 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4295 
  4296 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4297 product is now "<*>" instead of "Times"; the lexicographic product is
  4298 now "<*lex*>" instead of "**";
  4299 
  4300 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4301 of main HOL, but was unused); better use HOL's datatype package;
  4302 
  4303 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4304 the old syntax may be recovered as follows:
  4305 
  4306   syntax (symbols)
  4307     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4308       (infixl "\\<oplus>" 100)
  4309 
  4310 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4311 
  4312 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4313 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4314 internally;
  4315 
  4316 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4317 changed from A/r to A//r;
  4318 
  4319 * ZF: new treatment of arithmetic (nat & int) may break some old
  4320 proofs;
  4321 
  4322 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4323 rulify -> rule_format, elimify -> elim_format, ...);
  4324 
  4325 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4326 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4327 should have to change intro!! to intro? only); replaced "delrule" by
  4328 "rule del";
  4329 
  4330 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4331 
  4332 * Provers: strengthened force_tac by using new first_best_tac;
  4333 
  4334 * LaTeX document preparation: several changes of isabelle.sty (see
  4335 lib/texinputs);
  4336 
  4337 
  4338 *** Document preparation ***
  4339 
  4340 * formal comments (text blocks etc.) in new-style theories may now
  4341 contain antiquotations of thm/prop/term/typ/text to be presented
  4342 according to latex print mode; concrete syntax is like this:
  4343 @{term[show_types] "f(x) = a + x"};
  4344 
  4345 * isatool mkdir provides easy setup of Isabelle session directories,
  4346 including proper document sources;
  4347 
  4348 * generated LaTeX sources are now deleted after successful run
  4349 (isatool document -c); may retain a copy somewhere else via -D option
  4350 of isatool usedir;
  4351 
  4352 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4353 style files, achieving self-contained LaTeX sources and simplifying
  4354 LaTeX debugging;
  4355 
  4356 * old-style theories now produce (crude) LaTeX output as well;
  4357 
  4358 * browser info session directories are now self-contained (may be put
  4359 on WWW server seperately); improved graphs of nested sessions; removed
  4360 graph for 'all sessions';
  4361 
  4362 * several improvements in isabelle style files; \isabellestyle{it}
  4363 produces fake math mode output; \isamarkupheader is now \section by
  4364 default; see lib/texinputs/isabelle.sty etc.;
  4365 
  4366 
  4367 *** Isar ***
  4368 
  4369 * Isar/Pure: local results and corresponding term bindings are now
  4370 subject to Hindley-Milner polymorphism (similar to ML); this
  4371 accommodates incremental type-inference very nicely;
  4372 
  4373 * Isar/Pure: new derived language element 'obtain' supports
  4374 generalized existence reasoning;
  4375 
  4376 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4377 support accumulation of results, without applying any rules yet;
  4378 useful to collect intermediate results without explicit name
  4379 references, and for use with transitivity rules with more than 2
  4380 premises;
  4381 
  4382 * Isar/Pure: scalable support for case-analysis type proofs: new
  4383 'case' language element refers to local contexts symbolically, as
  4384 produced by certain proof methods; internally, case names are attached
  4385 to theorems as "tags";
  4386 
  4387 * Isar/Pure: theory command 'hide' removes declarations from
  4388 class/type/const name spaces;
  4389 
  4390 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4391 indicate potential overloading;
  4392 
  4393 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4394 
  4395 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4396 "{a,b,c}" instead of {a,b,c};
  4397 
  4398 * Isar/Pure now provides its own version of intro/elim/dest
  4399 attributes; useful for building new logics, but beware of confusion
  4400 with the version in Provers/classical;
  4401 
  4402 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4403 case name 'antecedent';
  4404 
  4405 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4406 to the current context is now done automatically);
  4407 
  4408 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4409 for definining proof methods in ML;
  4410 
  4411 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4412 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4413 most cases, one should have to change intro!! to intro? only);
  4414 replaced "delrule" by "rule del";
  4415 
  4416 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4417 'symmetric' attribute (the latter supercedes [RS sym]);
  4418 
  4419 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4420 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4421 well (including splits);
  4422 
  4423 * Isar/Provers: Simplifier and Classical methods now support all kind
  4424 of modifiers used in the past, including 'cong', 'iff', etc.
  4425 
  4426 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4427 of Simplifier and Classical reasoner);
  4428 
  4429 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4430 now support named cases; major packages (inductive, datatype, primrec,
  4431 recdef) support case names and properly name parameters;
  4432 
  4433 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4434 monotonicity conditions are extracted to be proven at end of
  4435 calculations;
  4436 
  4437 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4438 method anyway;
  4439 
  4440 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4441 split_if split_if_asm; datatype package provides theorems foo.splits =
  4442 foo.split foo.split_asm for each datatype;
  4443 
  4444 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4445 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4446 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4447 use "(cases (simplified))" method in proper proof texts);
  4448 
  4449 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4450 
  4451 * Isar: names of theorems etc. may be natural numbers as well;
  4452 
  4453 * Isar: 'pr' command: optional arguments for goals_limit and
  4454 ProofContext.prems_limit; no longer prints theory contexts, but only
  4455 proof states;
  4456 
  4457 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4458 additional print modes to be specified; e.g. "pr(latex)" will print
  4459 proof state according to the Isabelle LaTeX style;
  4460 
  4461 * Isar: improved support for emulating tactic scripts, including proof
  4462 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4463 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4464 (for HOL datatypes);
  4465 
  4466 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4467 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4468 'proof method scripts' have to be in depth-first order;
  4469 
  4470 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4471 
  4472 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4473 should instead use individual commands for printing items
  4474 (print_commands, print_methods etc.);
  4475 
  4476 * Isar: added 'nothing' --- the empty list of theorems;
  4477 
  4478 
  4479 *** HOL ***
  4480 
  4481 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4482 corresponding virtual machine and a specification of its bytecode
  4483 verifier and a lightweight bytecode verifier, including proofs of
  4484 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4485 Cornelia Pusch (see also the homepage of project Bali at
  4486 http://isabelle.in.tum.de/Bali/);
  4487 
  4488 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4489 Clemens Ballarin;
  4490 
  4491 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4492 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4493 Rasmussen;
  4494 
  4495 * HOL/Lattice: fundamental concepts of lattice theory and order
  4496 structures, including duals, properties of bounds versus algebraic
  4497 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4498 Theorem for complete lattices etc.; may also serve as a demonstration
  4499 for abstract algebraic reasoning using axiomatic type classes, and
  4500 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4501 
  4502 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4503 von Oheimb;
  4504 
  4505 * HOL/IMPP: extension of IMP with local variables and mutually
  4506 recursive procedures, by David von Oheimb;
  4507 
  4508 * HOL/Lambda: converted into new-style theory and document;
  4509 
  4510 * HOL/ex/Multiquote: example of multiple nested quotations and
  4511 anti-quotations -- basically a generalized version of de-Bruijn
  4512 representation; very useful in avoiding lifting of operations;
  4513 
  4514 * HOL/record: added general record equality rule to simpset; fixed
  4515 select-update simplification procedure to handle extended records as
  4516 well; admit "r" as field name;
  4517 
  4518 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4519 other numeric types and also as the identity of groups, rings, etc.;
  4520 
  4521 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4522 Types nat and int belong to this axclass;
  4523 
  4524 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4525    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4526    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4527   two terms #m*u and #n*u are replaced by #(m+n)*u
  4528     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4529   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4530     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4531 
  4532 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4533 powerful prover for predicate logic but knows nothing of clasets; see
  4534 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4535 
  4536 * HOL: new version of "case_tac" subsumes both boolean case split and
  4537 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4538 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4539 
  4540 * HOL: simplification no longer dives into case-expressions: only the
  4541 selector expression is simplified, but not the remaining arms; to
  4542 enable full simplification of case-expressions for datatype t, you may
  4543 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4544 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4545 
  4546 * HOL/recdef: the recursion equations generated by 'recdef' for
  4547 function 'f' are now called f.simps instead of f.rules; if all
  4548 termination conditions are proved automatically, these simplification
  4549 rules are added to the simpset, as in primrec; rules may be named
  4550 individually as well, resulting in a separate list of theorems for
  4551 each equation;
  4552 
  4553 * HOL/While is a new theory that provides a while-combinator. It
  4554 permits the definition of tail-recursive functions without the
  4555 provision of a termination measure. The latter is necessary once the
  4556 invariant proof rule for while is applied.
  4557 
  4558 * HOL: new (overloaded) notation for the set of elements below/above
  4559 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4560 
  4561 * HOL: theorems impI, allI, ballI bound as "strip";
  4562 
  4563 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4564 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4565 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4566 
  4567 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4568 
  4569 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4570 main HOL, but was unused);
  4571 
  4572 * HOL: fewer consts declared as global (e.g. have to refer to
  4573 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4574 
  4575 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4576 in case of overlap with user translations (e.g. judgements over
  4577 tuples); (note that the underlying logical represenation is still
  4578 bogus);
  4579 
  4580 
  4581 *** ZF ***
  4582 
  4583 * ZF: simplification automatically cancels common terms in arithmetic
  4584 expressions over nat and int;
  4585 
  4586 * ZF: new treatment of nat to minimize type-checking: all operators
  4587 coerce their operands to a natural number using the function natify,
  4588 making the algebraic laws unconditional;
  4589 
  4590 * ZF: as above, for int: operators coerce their operands to an integer
  4591 using the function intify;
  4592 
  4593 * ZF: the integer library now contains many of the usual laws for the
  4594 orderings, including $<=, and monotonicity laws for $+ and $*;
  4595 
  4596 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4597 simplification;
  4598 
  4599 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4600 to the simplifier and classical reasoner simultaneously;
  4601 
  4602 
  4603 *** General ***
  4604 
  4605 * Provers: blast_tac now handles actual object-logic rules as
  4606 assumptions; note that auto_tac uses blast_tac internally as well;
  4607 
  4608 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4609 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4610 
  4611 * Provers: delrules now handles destruct rules as well (no longer need
  4612 explicit make_elim);
  4613 
  4614 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4615   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4616 use instead the strong form,
  4617   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4618 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4619 from destruct-rules;
  4620 
  4621 * Provers: Simplifier.easy_setup provides a fast path to basic
  4622 Simplifier setup for new object-logics;
  4623 
  4624 * Pure: AST translation rules no longer require constant head on LHS;
  4625 
  4626 * Pure: improved name spaces: ambiguous output is qualified; support
  4627 for hiding of names;
  4628 
  4629 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4630 XSYMBOL_HOME; no longer need to do manual configuration in most
  4631 situations;
  4632 
  4633 * system: compression of ML heaps images may now be controlled via -c
  4634 option of isabelle and isatool usedir (currently only observed by
  4635 Poly/ML);
  4636 
  4637 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4638 useful for remote X11);
  4639 
  4640 * system: provide TAGS file for Isabelle sources;
  4641 
  4642 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4643 order;
  4644 
  4645 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4646 timing flag supersedes proof_timing and Toplevel.trace;
  4647 
  4648 * ML: new combinators |>> and |>>> for incremental transformations
  4649 with secondary results (e.g. certain theory extensions):
  4650 
  4651 * ML: PureThy.add_defs gets additional argument to indicate potential
  4652 overloading (usually false);
  4653 
  4654 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4655 results;
  4656 
  4657 
  4658 
  4659 New in Isabelle99 (October 1999)
  4660 --------------------------------
  4661 
  4662 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4663 
  4664 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4665 are no longer simplified.  (This allows the simplifier to unfold recursive
  4666 functional programs.)  To restore the old behaviour, declare
  4667 
  4668     Delcongs [if_weak_cong];
  4669 
  4670 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4671 complement;
  4672 
  4673 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4674 
  4675 * HOL/datatype: mutual_induct_tac no longer exists --
  4676   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4677 
  4678 * HOL/typedef: fixed type inference for representing set; type
  4679 arguments now have to occur explicitly on the rhs as type constraints;
  4680 
  4681 * ZF: The con_defs part of an inductive definition may no longer refer
  4682 to constants declared in the same theory;
  4683 
  4684 * HOL, ZF: the function mk_cases, generated by the inductive
  4685 definition package, has lost an argument.  To simplify its result, it
  4686 uses the default simpset instead of a supplied list of theorems.
  4687 
  4688 * HOL/List: the constructors of type list are now Nil and Cons;
  4689 
  4690 * Simplifier: the type of the infix ML functions
  4691         setSSolver addSSolver setSolver addSolver
  4692 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4693 for packaging solvers. A solver is created via
  4694         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4695 where the string argument is only a comment.
  4696 
  4697 
  4698 *** Proof tools ***
  4699 
  4700 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4701 decision procedure for linear arithmetic. Currently it is used for
  4702 types `nat', `int', and `real' in HOL (see below); it can, should and
  4703 will be instantiated for other types and logics as well.
  4704 
  4705 * The simplifier now accepts rewrite rules with flexible heads, eg
  4706      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4707   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4708   matching.
  4709 
  4710 
  4711 *** General ***
  4712 
  4713 * New Isabelle/Isar subsystem provides an alternative to traditional
  4714 tactical theorem proving; together with the ProofGeneral/isar user
  4715 interface it offers an interactive environment for developing human
  4716 readable proof documents (Isar == Intelligible semi-automated
  4717 reasoning); for further information see isatool doc isar-ref,
  4718 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4719 
  4720 * improved and simplified presentation of theories: better HTML markup
  4721 (including colors), graph views in several sizes; isatool usedir now
  4722 provides a proper interface for user theories (via -P option); actual
  4723 document preparation based on (PDF)LaTeX is available as well (for
  4724 new-style theories only); see isatool doc system for more information;
  4725 
  4726 * native support for Proof General, both for classic Isabelle and
  4727 Isabelle/Isar;
  4728 
  4729 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4730 using the graph browser tool;
  4731 
  4732 * Isabelle manuals now also available as PDF;
  4733 
  4734 * theory loader rewritten from scratch (may not be fully
  4735 bug-compatible); old loadpath variable has been replaced by show_path,
  4736 add_path, del_path, reset_path functions; new operations such as
  4737 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4738 isatool doc ref);
  4739 
  4740 * improved isatool install: option -k creates KDE application icon,
  4741 option -p DIR installs standalone binaries;
  4742 
  4743 * added ML_PLATFORM setting (useful for cross-platform installations);
  4744 more robust handling of platform specific ML images for SML/NJ;
  4745 
  4746 * the settings environment is now statically scoped, i.e. it is never
  4747 created again in sub-processes invoked from isabelle, isatool, or
  4748 Isabelle;
  4749 
  4750 * path element specification '~~' refers to '$ISABELLE_HOME';
  4751 
  4752 * in locales, the "assumes" and "defines" parts may be omitted if
  4753 empty;
  4754 
  4755 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4756 long arrows);
  4757 
  4758 * new print_mode "HTML";
  4759 
  4760 * new flag show_tags controls display of tags of theorems (which are
  4761 basically just comments that may be attached by some tools);
  4762 
  4763 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4764 mode and goal output format:
  4765 
  4766 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4767 244c244
  4768 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4769 ---
  4770 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4771 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4772 181c181
  4773 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4774 ---
  4775 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4776 
  4777 * function bind_thms stores lists of theorems (cf. bind_thm);
  4778 
  4779 * new shorthand tactics ftac, eatac, datac, fatac;
  4780 
  4781 * qed (and friends) now accept "" as result name; in that case the
  4782 theorem is not stored, but proper checks and presentation of the
  4783 result still apply;
  4784 
  4785 * theorem database now also indexes constants "Trueprop", "all",
  4786 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4787 
  4788 
  4789 *** HOL ***
  4790 
  4791 ** HOL arithmetic **
  4792 
  4793 * There are now decision procedures for linear arithmetic over nat and
  4794 int:
  4795 
  4796 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4797 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4798 are treated as atomic; subformulae not involving type `nat' or `int'
  4799 are ignored; quantified subformulae are ignored unless they are
  4800 positive universal or negative existential. The tactic has to be
  4801 invoked by hand and can be a little bit slow. In particular, the
  4802 running time is exponential in the number of occurrences of `min' and
  4803 `max', and `-' on `nat'.
  4804 
  4805 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4806 (negated) (in)equalities among the premises and the conclusion into
  4807 account (i.e. no compound formulae) and does not know about `min' and
  4808 `max', and `-' on `nat'. It is fast and is used automatically by the
  4809 simplifier.
  4810 
  4811 NB: At the moment, these decision procedures do not cope with mixed
  4812 nat/int formulae where the two parts interact, such as `m < n ==>
  4813 int(m) < int(n)'.
  4814 
  4815 * HOL/Numeral provides a generic theory of numerals (encoded
  4816 efficiently as bit strings); setup for types nat/int/real is in place;
  4817 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4818 int, existing theories and proof scripts may require a few additional
  4819 type constraints;
  4820 
  4821 * integer division and remainder can now be performed on constant
  4822 arguments;
  4823 
  4824 * many properties of integer multiplication, division and remainder
  4825 are now available;
  4826 
  4827 * An interface to the Stanford Validity Checker (SVC) is available through the
  4828 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4829 are proved automatically.  SVC must be installed separately, and its results
  4830 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4831 invocation of the underlying oracle).  For SVC see
  4832   http://verify.stanford.edu/SVC
  4833 
  4834 * IsaMakefile: the HOL-Real target now builds an actual image;
  4835 
  4836 
  4837 ** HOL misc **
  4838 
  4839 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4840 (in Isabelle/Isar) -- by Gertrud Bauer;
  4841 
  4842 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4843 analysis for assembly languages with subtypes;
  4844 
  4845 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4846 -- avoids syntactic ambiguities and treats state, transition, and
  4847 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4848 changed syntax and (many) tactics;
  4849 
  4850 * HOL/inductive: Now also handles more general introduction rules such
  4851   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4852   theorems are now maintained within the theory (maintained via the
  4853   "mono" attribute);
  4854 
  4855 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4856   (using function types) such as
  4857 
  4858   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4859 
  4860 * HOL/record: record_simproc (part of the default simpset) takes care
  4861 of selectors applied to updated records; record_split_tac is no longer
  4862 part of the default claset; update_defs may now be removed from the
  4863 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4864 
  4865   claset_ref () := claset() addSWrapper record_split_wrapper;
  4866   Delsimprocs [record_simproc]
  4867 
  4868 * HOL/typedef: fixed type inference for representing set; type
  4869 arguments now have to occur explicitly on the rhs as type constraints;
  4870 
  4871 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4872 names rather than an ML expression;
  4873 
  4874 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4875 supplied later.  Program schemes can be defined, such as
  4876     "While B C s = (if B s then While B C (C s) else s)"
  4877 where the well-founded relation can be chosen after B and C have been given.
  4878 
  4879 * HOL/List: the constructors of type list are now Nil and Cons;
  4880 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4881 course, ML tools referring to List.list.op # etc. have to be adapted;
  4882 
  4883 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4884 disabled by default; run isabelle with option -m HOL to get back to
  4885 the original Gordon/HOL-style output;
  4886 
  4887 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4888 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4889 
  4890 * HOL basic syntax simplified (more orthogonal): all variants of
  4891 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4892 Eps operator is provided as well: "SOME x. P[x]";
  4893 
  4894 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4895 
  4896 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4897 thus available for user theories;
  4898 
  4899 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4900 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4901 time;
  4902 
  4903 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4904 several times and then mp;
  4905 
  4906 
  4907 *** LK ***
  4908 
  4909 * the notation <<...>> is now available as a notation for sequences of
  4910 formulas;
  4911 
  4912 * the simplifier is now installed
  4913 
  4914 * the axiom system has been generalized (thanks to Soren Heilmann)
  4915 
  4916 * the classical reasoner now has a default rule database
  4917 
  4918 
  4919 *** ZF ***
  4920 
  4921 * new primrec section allows primitive recursive functions to be given
  4922 directly (as in HOL) over datatypes and the natural numbers;
  4923 
  4924 * new tactics induct_tac and exhaust_tac for induction (or case
  4925 analysis) over datatypes and the natural numbers;
  4926 
  4927 * the datatype declaration of type T now defines the recursor T_rec;
  4928 
  4929 * simplification automatically does freeness reasoning for datatype
  4930 constructors;
  4931 
  4932 * automatic type-inference, with AddTCs command to insert new
  4933 type-checking rules;
  4934 
  4935 * datatype introduction rules are now added as Safe Introduction rules
  4936 to the claset;
  4937 
  4938 * the syntax "if P then x else y" is now available in addition to
  4939 if(P,x,y);
  4940 
  4941 
  4942 *** Internal programming interfaces ***
  4943 
  4944 * tuned simplifier trace output; new flag debug_simp;
  4945 
  4946 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4947 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4948 
  4949 * AxClass.axclass_tac lost the theory argument;
  4950 
  4951 * tuned current_goals_markers semantics: begin / end goal avoids
  4952 printing empty lines;
  4953 
  4954 * removed prs and prs_fn hook, which was broken because it did not
  4955 include \n in its semantics, forcing writeln to add one
  4956 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4957 string -> unit if you really want to output text without newline;
  4958 
  4959 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4960 plain output, interface builders may have to enable 'isabelle_font'
  4961 mode to get Isabelle font glyphs as before;
  4962 
  4963 * refined token_translation interface; INCOMPATIBILITY: output length
  4964 now of type real instead of int;
  4965 
  4966 * theory loader actions may be traced via new ThyInfo.add_hook
  4967 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4968 your own database of information attached to *whole* theories -- as
  4969 opposed to intra-theory data slots offered via TheoryDataFun;
  4970 
  4971 * proper handling of dangling sort hypotheses (at last!);
  4972 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4973 extra sort hypotheses that can be witnessed from the type signature;
  4974 the force_strip_shyps flag is gone, any remaining shyps are simply
  4975 left in the theorem (with a warning issued by strip_shyps_warning);
  4976 
  4977 
  4978 
  4979 New in Isabelle98-1 (October 1998)
  4980 ----------------------------------
  4981 
  4982 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4983 
  4984 * several changes of automated proof tools;
  4985 
  4986 * HOL: major changes to the inductive and datatype packages, including
  4987 some minor incompatibilities of theory syntax;
  4988 
  4989 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4990 called `inj_on';
  4991 
  4992 * HOL: removed duplicate thms in Arith:
  4993   less_imp_add_less  should be replaced by  trans_less_add1
  4994   le_imp_add_le      should be replaced by  trans_le_add1
  4995 
  4996 * HOL: unary minus is now overloaded (new type constraints may be
  4997 required);
  4998 
  4999 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5000 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5001 now taken as an integer constant.
  5002 
  5003 * Pure: ML function 'theory_of' renamed to 'theory';
  5004 
  5005 
  5006 *** Proof tools ***
  5007 
  5008 * Simplifier:
  5009   1. Asm_full_simp_tac is now more aggressive.
  5010      1. It will sometimes reorient premises if that increases their power to
  5011         simplify.
  5012      2. It does no longer proceed strictly from left to right but may also
  5013         rotate premises to achieve further simplification.
  5014      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5015      old Asm_full_simp_tac in that it does not rotate premises.
  5016   2. The simplifier now knows a little bit about nat-arithmetic.
  5017 
  5018 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5019 allows for selected deletion of wrappers, by introduction of names for
  5020 wrapper functionals.  This implies that addbefore, addSbefore,
  5021 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5022 and that adding two tactics with the same name overwrites the first
  5023 one (emitting a warning).
  5024   type wrapper = (int -> tactic) -> (int -> tactic)
  5025   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5026   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5027   delWrapper, delSWrapper: claset *  string            -> claset
  5028   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5029 
  5030 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5031 semantics; addbefore now affects only the unsafe part of step_tac
  5032 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5033 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5034 by Force_tac;
  5035 
  5036 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5037 compWrapper; added safe wrapper (and access functions for it);
  5038 
  5039 * HOL/split_all_tac is now much faster and fails if there is nothing
  5040 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5041 and the names of the automatically generated variables have changed.
  5042 split_all_tac has moved within claset() from unsafe wrappers to safe
  5043 wrappers, which means that !!-bound variables are split much more
  5044 aggressively, and safe_tac and clarify_tac now split such variables.
  5045 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5046 Note: the same holds for record_split_tac, which does the job of
  5047 split_all_tac for record fields.
  5048 
  5049 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5050 permanently to the default simpset using Addsplits just like
  5051 Addsimps. They can be removed via Delsplits just like
  5052 Delsimps. Lower-case versions are also available.
  5053 
  5054 * HOL/Simplifier: The rule split_if is now part of the default
  5055 simpset. This means that the simplifier will eliminate all occurrences
  5056 of if-then-else in the conclusion of a goal. To prevent this, you can
  5057 either remove split_if completely from the default simpset by
  5058 `Delsplits [split_if]' or remove it in a specific call of the
  5059 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5060 other case splitting rules to/from the default simpset: every datatype
  5061 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5062 t is the name of the datatype).
  5063 
  5064 * Classical reasoner / Simplifier combination: new force_tac (and
  5065 derivatives Force_tac, force) combines rewriting and classical
  5066 reasoning (and whatever other tools) similarly to auto_tac, but is
  5067 aimed to solve the given subgoal completely.
  5068 
  5069 
  5070 *** General ***
  5071 
  5072 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5073 and `goalw': the theory is no longer needed as an explicit argument -
  5074 the current theory context is used; assumptions are no longer returned
  5075 at the ML-level unless one of them starts with ==> or !!; it is
  5076 recommended to convert to these new commands using isatool fixgoal
  5077 (backup your sources first!);
  5078 
  5079 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5080 the current theory context, and 'theory' to lookup stored theories;
  5081 
  5082 * new theory section 'locale' for declaring constants, assumptions and
  5083 definitions that have local scope;
  5084 
  5085 * new theory section 'nonterminals' for purely syntactic types;
  5086 
  5087 * new theory section 'setup' for generic ML setup functions
  5088 (e.g. package initialization);
  5089 
  5090 * the distribution now includes Isabelle icons: see
  5091 lib/logo/isabelle-{small,tiny}.xpm;
  5092 
  5093 * isatool install - install binaries with absolute references to
  5094 ISABELLE_HOME/bin;
  5095 
  5096 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5097 
  5098 * print mode 'emacs' reserved for Isamode;
  5099 
  5100 * support multiple print (ast) translations per constant name;
  5101 
  5102 * theorems involving oracles are now printed with a suffixed [!];
  5103 
  5104 
  5105 *** HOL ***
  5106 
  5107 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5108 
  5109 * HOL/inductive package reorganized and improved: now supports mutual
  5110 definitions such as
  5111 
  5112   inductive EVEN ODD
  5113     intrs
  5114       null "0 : EVEN"
  5115       oddI "n : EVEN ==> Suc n : ODD"
  5116       evenI "n : ODD ==> Suc n : EVEN"
  5117 
  5118 new theorem list "elims" contains an elimination rule for each of the
  5119 recursive sets; inductive definitions now handle disjunctive premises
  5120 correctly (also ZF);
  5121 
  5122 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5123 "mutual_induct" no longer exists - the induction rule is always
  5124 contained in "induct";
  5125 
  5126 
  5127 * HOL/datatype package re-implemented and greatly improved: now
  5128 supports mutually recursive datatypes such as
  5129 
  5130   datatype
  5131     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5132             | SUM ('a aexp) ('a aexp)
  5133             | DIFF ('a aexp) ('a aexp)
  5134             | NUM 'a
  5135   and
  5136     'a bexp = LESS ('a aexp) ('a aexp)
  5137             | AND ('a bexp) ('a bexp)
  5138             | OR ('a bexp) ('a bexp)
  5139 
  5140 as well as indirectly recursive datatypes such as
  5141 
  5142   datatype
  5143     ('a, 'b) term = Var 'a
  5144                   | App 'b ((('a, 'b) term) list)
  5145 
  5146 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5147 induction on mutually / indirectly recursive datatypes.
  5148 
  5149 Primrec equations are now stored in theory and can be accessed via
  5150 <function_name>.simps.
  5151 
  5152 INCOMPATIBILITIES:
  5153 
  5154   - Theories using datatypes must now have theory Datatype as an
  5155     ancestor.
  5156   - The specific <typename>.induct_tac no longer exists - use the
  5157     generic induct_tac instead.
  5158   - natE has been renamed to nat.exhaust - use exhaust_tac
  5159     instead of res_inst_tac ... natE. Note that the variable
  5160     names in nat.exhaust differ from the names in natE, this
  5161     may cause some "fragile" proofs to fail.
  5162   - The theorems split_<typename>_case and split_<typename>_case_asm
  5163     have been renamed to <typename>.split and <typename>.split_asm.
  5164   - Since default sorts of type variables are now handled correctly,
  5165     some datatype definitions may have to be annotated with explicit
  5166     sort constraints.
  5167   - Primrec definitions no longer require function name and type
  5168     of recursive argument.
  5169 
  5170 Consider using isatool fixdatatype to adapt your theories and proof
  5171 scripts to the new package (backup your sources first!).
  5172 
  5173 
  5174 * HOL/record package: considerably improved implementation; now
  5175 includes concrete syntax for record types, terms, updates; theorems
  5176 for surjective pairing and splitting !!-bound record variables; proof
  5177 support is as follows:
  5178 
  5179   1) standard conversions (selectors or updates applied to record
  5180 constructor terms) are part of the standard simpset;
  5181 
  5182   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5183 made part of standard simpset and claset via addIffs;
  5184 
  5185   3) a tactic for record field splitting (record_split_tac) is part of
  5186 the standard claset (addSWrapper);
  5187 
  5188 To get a better idea about these rules you may retrieve them via
  5189 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5190 the name of your record type.
  5191 
  5192 The split tactic 3) conceptually simplifies by the following rule:
  5193 
  5194   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5195 
  5196 Thus any record variable that is bound by meta-all will automatically
  5197 blow up into some record constructor term, consequently the
  5198 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5199 solve record problems automatically.
  5200 
  5201 
  5202 * reorganized the main HOL image: HOL/Integ and String loaded by
  5203 default; theory Main includes everything;
  5204 
  5205 * automatic simplification of integer sums and comparisons, using cancellation;
  5206 
  5207 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5208 
  5209 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5210 
  5211 * many new identities for unions, intersections, set difference, etc.;
  5212 
  5213 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5214 called split_if, split_split, split_sum_case and split_nat_case (to go
  5215 with add/delsplits);
  5216 
  5217 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5218 (?x::unit) = (); this is made part of the default simpset, which COULD
  5219 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5220 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5221 unit_abs_eta_conv is added in order to counter the effect of
  5222 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5223 %u.f();
  5224 
  5225 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5226 makes more sense);
  5227 
  5228 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5229   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5230   disjointness reasoning but breaking a few old proofs.
  5231 
  5232 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5233 to 'converse' from 'inverse' (for compatibility with ZF and some
  5234 literature);
  5235 
  5236 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5237 the well-founded relation;
  5238 
  5239 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5240     Compl A.  The "Compl" syntax remains available as input syntax for this
  5241     release ONLY.
  5242 
  5243 * HOL/Update: new theory of function updates:
  5244     f(a:=b) == %x. if x=a then b else f x
  5245 may also be iterated as in f(a:=b,c:=d,...);
  5246 
  5247 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5248 
  5249 * HOL/List:
  5250   - new function list_update written xs[i:=v] that updates the i-th
  5251     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5252   - new function `upt' written [i..j(] which generates the list
  5253     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5254     bound write [i..j], which is a shorthand for [i..j+1(].
  5255   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5256 
  5257 * HOL/Arith:
  5258   - removed 'pred' (predecessor) function;
  5259   - generalized some theorems about n-1;
  5260   - many new laws about "div" and "mod";
  5261   - new laws about greatest common divisors (see theory ex/Primes);
  5262 
  5263 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5264 instead of "inverse";
  5265 
  5266 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5267   of the multiset ordering;
  5268 
  5269 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5270   (not included by default);
  5271 
  5272 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5273 
  5274 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5275   programs, i.e. different program variables may have different types.
  5276 
  5277 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5278   [previously, this check worked only if the rewrite rule was unconditional]
  5279   Now rew can involve either definitions or equalities (either == or =).
  5280 
  5281 
  5282 *** ZF ***
  5283 
  5284 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5285   only the theorems proved on ZF.ML;
  5286 
  5287 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5288   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5289   disjointness reasoning but breaking a few old proofs.
  5290 
  5291 * ZF/Update: new theory of function updates
  5292     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5293   may also be iterated as in f(a:=b,c:=d,...);
  5294 
  5295 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5296 
  5297 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5298   [previously, this check worked only if the rewrite rule was unconditional]
  5299   Now rew can involve either definitions or equalities (either == or =).
  5300 
  5301 * case_tac provided for compatibility with HOL
  5302     (like the old excluded_middle_tac, but with subgoals swapped)
  5303 
  5304 
  5305 *** Internal programming interfaces ***
  5306 
  5307 * Pure: several new basic modules made available for general use, see
  5308 also src/Pure/README;
  5309 
  5310 * improved the theory data mechanism to support encapsulation (data
  5311 kind name replaced by private Object.kind, acting as authorization
  5312 key); new type-safe user interface via functor TheoryDataFun; generic
  5313 print_data function becomes basically useless;
  5314 
  5315 * removed global_names compatibility flag -- all theory declarations
  5316 are qualified by default;
  5317 
  5318 * module Pure/Syntax now offers quote / antiquote translation
  5319 functions (useful for Hoare logic etc. with implicit dependencies);
  5320 see HOL/ex/Antiquote for an example use;
  5321 
  5322 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5323 cterm -> thm;
  5324 
  5325 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5326 subgoal;
  5327 
  5328 * Display.print_goals function moved to Locale.print_goals;
  5329 
  5330 * standard print function for goals supports current_goals_markers
  5331 variable for marking begin of proof, end of proof, start of goal; the
  5332 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5333 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5334 for example;
  5335 
  5336 
  5337 
  5338 New in Isabelle98 (January 1998)
  5339 --------------------------------
  5340 
  5341 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5342 
  5343 * changed lexical syntax of terms / types: dots made part of long
  5344 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5345 
  5346 * simpset (and claset) reference variable replaced by functions
  5347 simpset / simpset_ref;
  5348 
  5349 * no longer supports theory aliases (via merge) and non-trivial
  5350 implicit merge of thms' signatures;
  5351 
  5352 * most internal names of constants changed due to qualified names;
  5353 
  5354 * changed Pure/Sequence interface (see Pure/seq.ML);
  5355 
  5356 
  5357 *** General Changes ***
  5358 
  5359 * hierachically structured name spaces (for consts, types, axms, thms
  5360 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5361 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5362 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5363 long_names for fully qualified output names; NOTE: ML programs
  5364 (special tactics, packages etc.) referring to internal names may have
  5365 to be adapted to cope with fully qualified names; in case of severe
  5366 backward campatibility problems try setting 'global_names' at compile
  5367 time to have enrything declared within a flat name space; one may also
  5368 fine tune name declarations in theories via the 'global' and 'local'
  5369 section;
  5370 
  5371 * reimplemented the implicit simpset and claset using the new anytype
  5372 data filed in signatures; references simpset:simpset ref etc. are
  5373 replaced by functions simpset:unit->simpset and
  5374 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5375 to patch your ML files accordingly;
  5376 
  5377 * HTML output now includes theory graph data for display with Java
  5378 applet or isatool browser; data generated automatically via isatool
  5379 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5380 
  5381 * defs may now be conditional; improved rewrite_goals_tac to handle
  5382 conditional equations;
  5383 
  5384 * defs now admits additional type arguments, using TYPE('a) syntax;
  5385 
  5386 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5387 creates a new theory node; implicit merge of thms' signatures is
  5388 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5389 transfer:theory->thm->thm in (rare) cases;
  5390 
  5391 * improved handling of draft signatures / theories; draft thms (and
  5392 ctyps, cterms) are automatically promoted to real ones;
  5393 
  5394 * slightly changed interfaces for oracles: admit many per theory, named
  5395 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5396 
  5397 * print_goals: optional output of const types (set show_consts and
  5398 show_types);
  5399 
  5400 * improved output of warnings (###) and errors (***);
  5401 
  5402 * subgoal_tac displays a warning if the new subgoal has type variables;
  5403 
  5404 * removed old README and Makefiles;
  5405 
  5406 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5407 
  5408 * removed obsolete init_pps and init_database;
  5409 
  5410 * deleted the obsolete tactical STATE, which was declared by
  5411     fun STATE tacfun st = tacfun st st;
  5412 
  5413 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5414 (which abbreviates $HOME);
  5415 
  5416 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5417 use isatool fixseq to adapt your ML programs (this works for fully
  5418 qualified references to the Sequence structure only!);
  5419 
  5420 * use_thy no longer requires writable current directory; it always
  5421 reloads .ML *and* .thy file, if either one is out of date;
  5422 
  5423 
  5424 *** Classical Reasoner ***
  5425 
  5426 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5427 tactics that use classical reasoning to simplify a subgoal without
  5428 splitting it into several subgoals;
  5429 
  5430 * Safe_tac: like safe_tac but uses the default claset;
  5431 
  5432 
  5433 *** Simplifier ***
  5434 
  5435 * added simplification meta rules:
  5436     (asm_)(full_)simplify: simpset -> thm -> thm;
  5437 
  5438 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5439 logics (again);
  5440 
  5441 * added prems argument to simplification procedures;
  5442 
  5443 * HOL, FOL, ZF: added infix function `addsplits':
  5444   instead of `<simpset> setloop (split_tac <thms>)'
  5445   you can simply write `<simpset> addsplits <thms>'
  5446 
  5447 
  5448 *** Syntax ***
  5449 
  5450 * TYPE('a) syntax for type reflection terms;
  5451 
  5452 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5453 
  5454 * pretty printer: changed order of mixfix annotation preference (again!);
  5455 
  5456 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5457 
  5458 
  5459 *** HOL ***
  5460 
  5461 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5462   with `addloop' of the simplifier to faciliate case splitting in premises.
  5463 
  5464 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5465 
  5466 * HOL/Auth: new protocol proofs including some for the Internet
  5467   protocol TLS;
  5468 
  5469 * HOL/Map: new theory of `maps' a la VDM;
  5470 
  5471 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5472 cancelling out common nat summands from =, <, <= (in)equalities, or
  5473 differences; simplification procedures nat_cancel_factor for
  5474 cancelling common factor from =, <, <= (in)equalities over natural
  5475 sums; nat_cancel contains both kinds of procedures, it is installed by
  5476 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5477 
  5478 * HOL/simplifier: terms of the form
  5479   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5480   are rewritten to
  5481   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5482   and those of the form
  5483   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5484   are rewritten to
  5485   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5486 
  5487 * HOL/datatype
  5488   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5489 
  5490   P(t_case f1 ... fn x) =
  5491      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5492         ...
  5493        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5494      )
  5495 
  5496   and a theorem `split_t_case_asm' of the form
  5497 
  5498   P(t_case f1 ... fn x) =
  5499     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5500         ...
  5501        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5502      )
  5503   which can be added to a simpset via `addsplits'. The existing theorems
  5504   expand_list_case and expand_option_case have been renamed to
  5505   split_list_case and split_option_case.
  5506 
  5507 * HOL/Arithmetic:
  5508   - `pred n' is automatically converted to `n-1'.
  5509     Users are strongly encouraged not to use `pred' any longer,
  5510     because it will disappear altogether at some point.
  5511   - Users are strongly encouraged to write "0 < n" rather than
  5512     "n ~= 0". Theorems and proof tools have been modified towards this
  5513     `standard'.
  5514 
  5515 * HOL/Lists:
  5516   the function "set_of_list" has been renamed "set" (and its theorems too);
  5517   the function "nth" now takes its arguments in the reverse order and
  5518   has acquired the infix notation "!" as in "xs!n".
  5519 
  5520 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5521 
  5522 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5523   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5524 
  5525 * HOL/record: extensible records with schematic structural subtyping
  5526 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5527 still lacks various theorems and concrete record syntax;
  5528 
  5529 
  5530 *** HOLCF ***
  5531 
  5532 * removed "axioms" and "generated by" sections;
  5533 
  5534 * replaced "ops" section by extended "consts" section, which is capable of
  5535   handling the continuous function space "->" directly;
  5536 
  5537 * domain package:
  5538   . proves theorems immediately and stores them in the theory,
  5539   . creates hierachical name space,
  5540   . now uses normal mixfix annotations (instead of cinfix...),
  5541   . minor changes to some names and values (for consistency),
  5542   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5543   . separator between mutual domain defs: changed "," to "and",
  5544   . improved handling of sort constraints;  now they have to
  5545     appear on the left-hand side of the equations only;
  5546 
  5547 * fixed LAM <x,y,zs>.b syntax;
  5548 
  5549 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5550 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5551 
  5552 
  5553 *** FOL and ZF ***
  5554 
  5555 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5556   with `addloop' of the simplifier to faciliate case splitting in premises.
  5557 
  5558 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5559 in HOL, they strip ALL and --> from proved theorems;
  5560 
  5561 
  5562 
  5563 New in Isabelle94-8 (May 1997)
  5564 ------------------------------
  5565 
  5566 *** General Changes ***
  5567 
  5568 * new utilities to build / run / maintain Isabelle etc. (in parts
  5569 still somewhat experimental); old Makefiles etc. still functional;
  5570 
  5571 * new 'Isabelle System Manual';
  5572 
  5573 * INSTALL text, together with ./configure and ./build scripts;
  5574 
  5575 * reimplemented type inference for greater efficiency, better error
  5576 messages and clean internal interface;
  5577 
  5578 * prlim command for dealing with lots of subgoals (an easier way of
  5579 setting goals_limit);
  5580 
  5581 
  5582 *** Syntax ***
  5583 
  5584 * supports alternative (named) syntax tables (parser and pretty
  5585 printer); internal interface is provided by add_modesyntax(_i);
  5586 
  5587 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5588 be used in conjunction with the Isabelle symbol font; uses the
  5589 "symbols" syntax table;
  5590 
  5591 * added token_translation interface (may translate name tokens in
  5592 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5593 the current print_mode); IMPORTANT: user print translation functions
  5594 are responsible for marking newly introduced bounds
  5595 (Syntax.mark_boundT);
  5596 
  5597 * token translations for modes "xterm" and "xterm_color" that display
  5598 names in bold, underline etc. or colors (which requires a color
  5599 version of xterm);
  5600 
  5601 * infixes may now be declared with names independent of their syntax;
  5602 
  5603 * added typed_print_translation (like print_translation, but may
  5604 access type of constant);
  5605 
  5606 
  5607 *** Classical Reasoner ***
  5608 
  5609 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5610 some limitations.  Blast_tac...
  5611   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5612   + ignores elimination rules that don't have the correct format
  5613         (the conclusion MUST be a formula variable)
  5614   + ignores types, which can make HOL proofs fail
  5615   + rules must not require higher-order unification, e.g. apply_type in ZF
  5616     [message "Function Var's argument not a bound variable" relates to this]
  5617   + its proof strategy is more general but can actually be slower
  5618 
  5619 * substitution with equality assumptions no longer permutes other
  5620 assumptions;
  5621 
  5622 * minor changes in semantics of addafter (now called addaltern); renamed
  5623 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5624 (and access functions for it);
  5625 
  5626 * improved combination of classical reasoner and simplifier:
  5627   + functions for handling clasimpsets
  5628   + improvement of addss: now the simplifier is called _after_ the
  5629     safe steps.
  5630   + safe variant of addss called addSss: uses safe simplifications
  5631     _during_ the safe steps. It is more complete as it allows multiple
  5632     instantiations of unknowns (e.g. with slow_tac).
  5633 
  5634 *** Simplifier ***
  5635 
  5636 * added interface for simplification procedures (functions that
  5637 produce *proven* rewrite rules on the fly, depending on current
  5638 redex);
  5639 
  5640 * ordering on terms as parameter (used for ordered rewriting);
  5641 
  5642 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5643 
  5644 * the solver is now split into a safe and an unsafe part.
  5645 This should be invisible for the normal user, except that the
  5646 functions setsolver and addsolver have been renamed to setSolver and
  5647 addSolver; added safe_asm_full_simp_tac;
  5648 
  5649 
  5650 *** HOL ***
  5651 
  5652 * a generic induction tactic `induct_tac' which works for all datatypes and
  5653 also for type `nat';
  5654 
  5655 * a generic case distinction tactic `exhaust_tac' which works for all
  5656 datatypes and also for type `nat';
  5657 
  5658 * each datatype comes with a function `size';
  5659 
  5660 * patterns in case expressions allow tuple patterns as arguments to
  5661 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5662 
  5663 * primrec now also works with type nat;
  5664 
  5665 * recdef: a new declaration form, allows general recursive functions to be
  5666 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5667 
  5668 * the constant for negation has been renamed from "not" to "Not" to
  5669 harmonize with FOL, ZF, LK, etc.;
  5670 
  5671 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5672 infinite lists;
  5673 
  5674 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5675 
  5676 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5677 problems in commutative rings, using axiomatic type classes for + and *;
  5678 
  5679 * more examples in HOL/MiniML and HOL/Auth;
  5680 
  5681 * more default rewrite rules for quantifiers, union/intersection;
  5682 
  5683 * a new constant `arbitrary == @x.False';
  5684 
  5685 * HOLCF/IOA replaces old HOL/IOA;
  5686 
  5687 * HOLCF changes: derived all rules and arities
  5688   + axiomatic type classes instead of classes
  5689   + typedef instead of faking type definitions
  5690   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5691   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5692   + eliminated the types void, one, tr
  5693   + use unit lift and bool lift (with translations) instead of one and tr
  5694   + eliminated blift from Lift3.thy (use Def instead of blift)
  5695   all eliminated rules are derived as theorems --> no visible changes ;
  5696 
  5697 
  5698 *** ZF ***
  5699 
  5700 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5701 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5702 as ZF_cs addSIs [equalityI];
  5703 
  5704 
  5705 
  5706 New in Isabelle94-7 (November 96)
  5707 ---------------------------------
  5708 
  5709 * allowing negative levels (as offsets) in prlev and choplev;
  5710 
  5711 * super-linear speedup for large simplifications;
  5712 
  5713 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5714 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5715 FAIL); can suppress it using the command Delsimps (ex_simps @
  5716 all_simps); De Morgan laws are also now included, by default;
  5717 
  5718 * improved printing of ==>  :  ~:
  5719 
  5720 * new object-logic "Sequents" adds linear logic, while replacing LK
  5721 and Modal (thanks to Sara Kalvala);
  5722 
  5723 * HOL/Auth: correctness proofs for authentication protocols;
  5724 
  5725 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5726 examples on HOL/Auth);
  5727 
  5728 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5729 the rewriter and classical reasoner simultaneously;
  5730 
  5731 * function uresult no longer returns theorems in "standard" format;
  5732 regain previous version by: val uresult = standard o uresult;
  5733 
  5734 
  5735 
  5736 New in Isabelle94-6
  5737 -------------------
  5738 
  5739 * oracles -- these establish an interface between Isabelle and trusted
  5740 external reasoners, which may deliver results as theorems;
  5741 
  5742 * proof objects (in particular record all uses of oracles);
  5743 
  5744 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5745 
  5746 * "constdefs" section in theory files;
  5747 
  5748 * "primrec" section (HOL) no longer requires names;
  5749 
  5750 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5751 
  5752 
  5753 
  5754 New in Isabelle94-5
  5755 -------------------
  5756 
  5757 * reduced space requirements;
  5758 
  5759 * automatic HTML generation from theories;
  5760 
  5761 * theory files no longer require "..." (quotes) around most types;
  5762 
  5763 * new examples, including two proofs of the Church-Rosser theorem;
  5764 
  5765 * non-curried (1994) version of HOL is no longer distributed;
  5766 
  5767 
  5768 
  5769 New in Isabelle94-4
  5770 -------------------
  5771 
  5772 * greatly reduced space requirements;
  5773 
  5774 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5775 
  5776 * searchable theorem database (see the section "Retrieving theorems" on
  5777 page 8 of the Reference Manual);
  5778 
  5779 * new examples, including Grabczewski's monumental case study of the
  5780 Axiom of Choice;
  5781 
  5782 * The previous version of HOL renamed to Old_HOL;
  5783 
  5784 * The new version of HOL (previously called CHOL) uses a curried syntax
  5785 for functions.  Application looks like f a b instead of f(a,b);
  5786 
  5787 * Mutually recursive inductive definitions finally work in HOL;
  5788 
  5789 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5790 translates to the operator "split";
  5791 
  5792 
  5793 
  5794 New in Isabelle94-3
  5795 -------------------
  5796 
  5797 * new infix operator, addss, allowing the classical reasoner to
  5798 perform simplification at each step of its search.  Example:
  5799         fast_tac (cs addss ss)
  5800 
  5801 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5802 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5803 look like (a,b) instead of <a,b>;
  5804 
  5805 * PLEASE NOTE: CHOL will eventually replace HOL!
  5806 
  5807 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5808 It translates to the operator "split".  A new theory of integers is available;
  5809 
  5810 * In ZF, integer numerals now denote two's-complement binary integers.
  5811 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5812 
  5813 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5814 of the Axiom of Choice;
  5815 
  5816 
  5817 
  5818 New in Isabelle94-2
  5819 -------------------
  5820 
  5821 * Significantly faster resolution;
  5822 
  5823 * the different sections in a .thy file can now be mixed and repeated
  5824 freely;
  5825 
  5826 * Database of theorems for FOL, HOL and ZF.  New
  5827 commands including qed, qed_goal and bind_thm store theorems in the database.
  5828 
  5829 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5830 a given theory (thms_of), or find out what theory a theorem was proved in
  5831 (theory_of_thm);
  5832 
  5833 * Bugs fixed in the inductive definition and datatype packages;
  5834 
  5835 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5836 and HOL_dup_cs obsolete;
  5837 
  5838 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5839 have been removed;
  5840 
  5841 * Simpler definition of function space in ZF;
  5842 
  5843 * new results about cardinal and ordinal arithmetic in ZF;
  5844 
  5845 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5846 types;
  5847 
  5848 :mode=text:wrap=hard:maxLineLen=72:
  5849 
  5850 
  5851 $Id$